MR fluid clutches, MR fluid clutch systems, MR fluid brakes, MR fluid brake systems, and pumping equipment

Abstract

The present invention provides an MR fluid clutch and an MR fluid brake that can suppress the temperature rise of the MR fluid and prevent leakage and deterioration of the MR fluid. [Solution] The MR fluid clutch 150 comprises a first rotating shaft 3, a second rotating shaft 4, a first rotating plate 5 connected to the first rotating shaft 3, a second rotating plate 6 connected to the second rotating shaft 4, an MR fluid chamber 20 containing MR fluid F that fills the gap between the first rotating plate 5 and the second rotating plate 6, a stationary housing 12 that houses the MR fluid chamber 20, an inlet 13 communicating with the MR fluid chamber 20 and allowing the medium L of the MR fluid F to flow into the MR fluid clutch from outside the MR fluid clutch, an outlet 14 communicating with the MR fluid chamber 20 and allowing the medium L inside the MR fluid clutch to flow out to the outside of the MR fluid clutch, and an electromagnet 28 that generates a magnetic field applied to the MR fluid F.

Description

Technical Field

[0001] The present invention relates to a clutch and an MR fluid clutch system using an MR fluid (magnetorheological fluid), and a brake and an MR fluid brake system using an MR fluid. The present invention also relates to a pump facility provided with a pump device incorporating an MR fluid clutch system.

Background Art

[0002] In a rotating machine such as a liquid pump device, a clutch has been conventionally used as a device for transmitting the rotation of a drive shaft to a driven shaft. The clutch connects the drive shaft and the driven shaft as needed, and rotates a load connected to the driven shaft by transmitting the rotation (or torque) of the drive shaft to the driven shaft. Further, by disengaging the clutch, the drive shaft can stop the rotation of the driven shaft while rotating.

[0003] As a means for transmitting the rotation of a drive shaft to a driven shaft, there is an MR fluid clutch (magnetorheological fluid clutch) using an MR fluid (magnetorheological fluid). The MR fluid is a fluid in which magnetic particles such as iron are dispersed in a fluid medium such as oil. The MR fluid has a property that its viscosity increases when a magnetic field is applied and returns to its original viscosity when the application of the magnetic field is stopped. The MR fluid clutch utilizes this property of the MR fluid to transmit the torque of the drive shaft to the driven shaft by applying a magnetic field to the MR fluid with an electromagnet, and blocks the transmission of torque to the driven shaft by stopping the application of the magnetic field. Further, the torque transmitted from the drive shaft to the driven shaft can be adjusted by the strength of the magnetic field applied to the MR fluid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] However, a major problem with conventional MR fluid clutches is that the temperature of the MR fluid rises due to friction between the MR fluid and the rotating plate, and friction between magnetic particles in the fluid medium. If the temperature of the MR fluid rises excessively, the thermal expansion of the MR fluid increases the pressure inside the housing filled with the MR fluid, causing the MR fluid to leak from the seal area or magnetic particles to migrate to the seal area, leading to premature wear of the seal material. In addition, when the MR fluid is hot, the medium in the MR fluid vaporizes, affecting torque transmission performance, and the magnetic particles may oxidize and deteriorate more easily. Similar problems can occur in MR fluid brakes (magnetorheological fluid brakes) that use MR fluid.

[0006] Therefore, the present invention provides an MR fluid clutch, an MR fluid clutch system, an MR fluid brake, and an MR fluid brake system that can suppress the temperature rise of the MR fluid and prevent leakage and deterioration of the MR fluid. The present invention also provides a pumping system equipped with a pump device incorporating such an MR fluid clutch system. [Means for solving the problem]

[0007] In one embodiment, an MR fluid clutch is provided, comprising: a first rotating shaft; a second rotating shaft; a first rotating plate connected to the first rotating shaft and rotatable integrally with the first rotating shaft; a second rotating plate connected to the second rotating shaft and rotatable integrally with the second rotating shaft; an MR fluid chamber containing MR fluid that fills the gap between the first rotating plate and the second rotating plate; a stationary housing housing the MR fluid chamber; an inlet communicating with the MR fluid chamber for allowing the medium of the MR fluid to flow into the MR fluid clutch from outside the MR fluid clutch; an outlet communicating with the MR fluid chamber for allowing the medium in the MR fluid clutch to flow out to the outside of the MR fluid clutch; and an electromagnet for generating a magnetic field applied to the MR fluid. In one embodiment, the MR fluid clutch further comprises a filter device that communicates with the MR fluid chamber and allows the passage of the medium without allowing magnetic particles in the MR fluid to pass through. In one embodiment, the filter device is a magnetic seal device having a filter channel that allows the medium to pass through, and a magnet arranged around the filter channel, wherein the magnetic field generated by the magnet prevents the magnetic particles from passing through the filter channel. In one embodiment, the filter device has a filtration accuracy smaller than the particle size of the magnetic particles.

[0008] In one embodiment, the MR fluid chamber is formed by a first axial structure having the first rotating shaft and the first rotating plate, a second axial structure having the second rotating shaft and the second rotating plate, and a sealing device that seals the gap between the first axial structure and the second axial structure. In one embodiment, the MR fluid clutch further comprises a medium chamber filled with the medium, which is in communication with the MR fluid chamber, the inlet, and the outlet, the medium chamber being formed by the stationary housing, the inlet and the outlet being provided in the stationary housing, and the filter device being positioned between the MR fluid chamber and the medium chamber. In one embodiment, the filter device is attached to the wall surface of the first axial structure that forms the MR fluid chamber. In one embodiment, the MR fluid clutch further comprises a first internal shaft passage formed inside the first rotating shaft and a second internal shaft passage formed inside the second rotating shaft, the first internal shaft passage and the second internal shaft passage communicating with the MR fluid chamber.

[0009] In one embodiment, an MR fluid clutch system is provided, comprising the MR fluid clutch, a medium tank storing the medium of the MR fluid, a medium circulation line for circulating the medium between the medium tank and the MR fluid chamber, and a pump located on the medium circulation line, the inlet and outlet of which are connected to the medium circulation line. In one embodiment, the MR fluid clutch is further provided with a filter device positioned between the medium circulation line and the MR fluid chamber, which allows the medium to pass through without allowing magnetic particles in the MR fluid to pass through. In one embodiment, the MR fluid clutch system further comprises a cooling device for cooling the medium flowing through the medium circulation line. In one embodiment, the MR fluid clutch system further includes a torque transmission mechanism that transmits the torque of a prime mover connected to the first rotating shaft to the pump.

[0010] In one embodiment, an MR fluid clutch system is provided, comprising: an MR fluid clutch; a medium tank storing the medium of the MR fluid; a medium circulation line for circulating the medium between the medium tank and the MR fluid chamber; and a pump disposed on the medium circulation line, wherein the MR fluid clutch further comprises a filter device disposed between the medium circulation line and the MR fluid chamber, which allows the medium to pass through without allowing magnetic particles in the MR fluid to pass through; the medium circulation line comprises a medium supply line for supplying the medium from the medium tank to the MR fluid chamber and a medium return line for returning the medium from the MR fluid chamber to the medium tank; the filter device comprises a first filter device connected to the medium supply line and a second filter device connected to the medium return line, the inlet being connected to the medium supply line via the first filter device and the outlet being connected to the medium return line via the second filter device. In one embodiment, the MR fluid clutch system further comprises a cooling device for cooling the medium flowing through the medium circulation line.

[0011] In one embodiment, a pumping system is provided that includes a pump device incorporating the above-mentioned MR fluid clutch system and a prime mover for driving the pump device.

[0012] In one embodiment, an MR fluid brake is provided, comprising a fixed shaft, a rotating shaft, a stationary plate connected to the fixed shaft, a rotating plate connected to the rotating shaft and rotatable integrally with the rotating shaft, an MR fluid chamber containing MR fluid that fills the gap between the stationary plate and the rotating plate, a stationary housing that houses the MR fluid chamber, an inlet communicating with the MR fluid chamber for introducing the medium of the MR fluid from outside the MR fluid brake, an outlet communicating with the MR fluid chamber for discharging the medium to the outside of the MR fluid brake, and an electromagnet for generating a magnetic field applied to the MR fluid. In one aspect, the MR fluid brake further includes a filter device that communicates with the MR fluid chamber and allows the medium to pass through while preventing magnetic particles in the MR fluid from passing through.

[0013] In one aspect, there is provided an MR fluid brake system including the above MR fluid brake, a medium tank in which the medium of the MR fluid is stored, a medium circulation line that circulates the medium between the medium tank and the MR fluid chamber, and a pump disposed in the medium circulation line. In one aspect, the MR fluid brake is disposed between the medium circulation line and the MR fluid chamber, and further includes a filter device that allows the medium to pass through while preventing magnetic particles in the MR fluid from passing through.

Advantages of the Invention

[0014] According to the present invention, by allowing the medium of the MR fluid to flow into the MR fluid chamber from the inlet communicating with the MR fluid chamber and allowing the medium of the MR fluid to flow out of the MR fluid chamber through the outlet communicating with the MR fluid chamber, it is possible to suppress the temperature rise of the MR fluid in the MR fluid chamber and prevent leakage and deterioration of the MR fluid.

Brief Description of the Drawings

[0015] [Figure 1] It is a cross-sectional view showing an embodiment of an MR fluid clutch system. [Figure 2] FIG. 2(a) is an enlarged cross-sectional view showing an embodiment of the filter device shown in FIG. 1, and FIG. 2(b) is a view seen from the direction indicated by arrow A in FIG. 2(a). [Figure 3] It is a flowchart for explaining an embodiment of the operation of the MR fluid clutch system shown in FIG. 1. [Figure 4] It is a cross-sectional view showing another embodiment of the MR fluid clutch system. [Figure 5] It is a cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 6] It is a cross-sectional view taken along line B-B of FIG. 5. [Figure 7]Cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 8] Cross-sectional view taken along line C-C in FIG. 7. [Figure 9] Cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 10] Cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 11] Cross-sectional view taken along line D-D in FIG. 10. [Figure 12] Cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 13] Cross-sectional view showing still another embodiment of the MR fluid clutch system. [Figure 14] Cross-sectional view showing an embodiment of the MR fluid brake system. [Figure 15] Schematic view showing an embodiment of pump equipment provided with a vertical shaft pump device incorporating an MR fluid clutch system.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of an MR fluid clutch system 100. As shown in FIG. 1, the MR fluid clutch system (magnetorheological fluid clutch system) 100 includes an MR fluid clutch 150 (magnetorheological fluid clutch), a medium circulation line 52 connected to the MR fluid clutch 150, a medium tank 50 in which a fluid medium (hereinafter referred to as "medium L") of the MR fluid (magnetorheological fluid) F is stored, and a pump 56 disposed in the medium circulation line 52.

[0017] The MR fluid clutch 150 includes a first shaft structure 1, a second shaft structure 2, and a stationary housing 12. The first shaft structure 1 and the second shaft structure 2 are surrounded by the stationary housing 12. In the present embodiment, the stationary housing 12 is made of a non-magnetic material.

[0018] The first shaft structure 1 includes a first rotating shaft 3, a first rotating plate 5, and a first connecting member 8. The first rotating shaft 3 is a rotatable shaft. The first rotating plate 5 is connected to the first rotating shaft 3 via the first connecting member 8. The first connecting member 8 is fixed to the first rotating shaft 3. The first rotating plate 5 has a radially expanding plane and is fixed to the inner circumference side of the first connecting member 8. The first rotating shaft 3, the first rotating plate 5, and the first connecting member 8 rotate together as the first rotating shaft 3 rotates.

[0019] The second axis structure 2 includes a second rotation axis 4, a second rotation plate 6, and a second connecting member 9. The second rotation axis 4 is a rotation axis that can rotate independently of the first rotation axis 3. The second rotation plate 6 is connected to the second rotation axis 4 via the second connecting member 9. The second connecting member 9 is fixed to the second rotation axis 4. The second rotation plate 6 has a radially extending plane and is fixed to the outer circumference of the second connecting member 9. The second rotation axis 4, the second rotation plate 6, and the second connecting member 9 rotate together as the second rotation axis 4 rotates. In this embodiment, the first rotation plate 5 and the second rotation plate 6 are made of a magnetic material (for example, a metal such as electromagnetic steel) with high permeability and low coercivity, while the first connecting member 8 and the second connecting member 9 are made of a non-magnetic material.

[0020] The first rotating shaft 3 and the second rotating shaft 4 are arranged in a straight line and are each rotatable independently. In this embodiment, the first rotating shaft 3 is a drive shaft (input shaft) connected to a prime mover 60 (e.g., an electric motor, gasoline engine, diesel engine, gas turbine engine, etc.), and the second rotating shaft 4 is a driven shaft (output shaft) connected to a load such as an impeller. In one embodiment, the second rotating shaft 4 may be a drive shaft (input shaft) connected to a prime mover, and the first rotating shaft 3 may be a driven shaft (output shaft) connected to a load. In this embodiment, the first rotating shaft 3 and the second rotating shaft 4 are made of a non-magnetic metallic material.

[0021] The MR fluid clutch 150 further comprises a first bearing 15 that rotatably supports a first rotating shaft 3, a second bearing 16 that rotatably supports a second rotating shaft 4, and an intermediate bearing 17 that rotatably supports a first connecting member 8. The first bearing 15, the second bearing 16, and the intermediate bearing 17 are held in a stationary housing 12. The first rotating shaft 3 is rotatably supported by the intermediate bearing 17 via the first connecting member 8.

[0022] The first bearing 15, the second bearing 16, and the intermediate bearing 17 are angular contact ball bearings capable of withstanding both radial and axial loads. However, the first bearing 15, the second bearing 16, and the intermediate bearing 17 may be of other types.

[0023] The MR fluid clutch 150 includes an MR fluid chamber 20 containing MR fluid F that fills the gap between the first rotating plate 5 and the second rotating plate 6, and an electromagnet 28 held in a stationary housing 12 that generates a magnetic field applied to the MR fluid F in the MR fluid chamber 20. The electromagnet 28 is supplied with current from a current supply device 30. The first rotating plate 5 and the second rotating plate 6 are arranged parallel to each other at a predetermined distance apart so that their planes face each other. The gap between the first rotating plate 5 and the second rotating plate 6 is located within the MR fluid chamber 20. The first connecting member 8 surrounds the second connecting member 9, and the MR fluid chamber 20 is formed by the first connecting member 8 and the second connecting member 9. The MR fluid chamber 20 is filled with MR fluid F. The MR fluid chamber 20 is housed inside the stationary housing 12.

[0024] MR fluid F is a fluid in which magnetic particles are dispersed in a medium L. Examples of materials for the magnetic particles include iron, carbonyl iron, iron nitride, iron carbide, low-carbon steel, nickel, and cobalt. Alternatively, it may be an iron alloy containing elements such as aluminum, silicon, cobalt, and nickel. It may also be paramagnetic, superparamagnetic, or ferromagnetic compound particles made of gadolinium, gadolinium organic derivatives, or mixtures thereof. The material for the magnetic particles is preferably carbonyl iron. The particle size of the magnetic particles is preferably several μm to several tens of μm as an average particle size.

[0025] Examples of the medium L include liquid fluids such as mineral oil, silicone oil, fluorine oil, paraffin, and water. The medium L is preferably low viscosity and has a viscosity such that the magnetic particles do not settle or aggregate. Furthermore, it is preferable that the medium L has a high boiling point. This is because the temperature of the MR fluid F rises due to friction between the MR fluid F and the first rotating plate 5 and the second rotating plate 6, and friction between the magnetic particles in the medium L. If the medium L boils at a low temperature, it can cause problems such as affecting the torque transmission performance of the MR fluid F. The medium L may contain thixotropic agents and antioxidants. The volume ratio of the medium L to the MR fluid F is preferably 15 to 45%, and more preferably 20 to 40%.

[0026] When a magnetic field is applied to the MR fluid F, the magnetic particles contained in the MR fluid F link together in a chain-like manner, increasing the viscosity of the MR fluid F (the MR fluid F solidifies). The high-viscosity MR fluid F connects the first rotating plate 5 and the second rotating plate 6. When the first rotating plate 5 and the second rotating plate 6 are connected, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate. On the other hand, when the application of the magnetic field to the MR fluid F is stopped, the MR fluid F returns to its original viscosity (liquefies), and the connection between the first rotating plate 5 and the second rotating plate 6 is released. When the connection between the first rotating plate 5 and the second rotating plate 6 is released, the transmission of the rotation (torque) of the first rotating shaft 3 to the second rotating shaft 4 stops, and the rotation of the load connected to the second rotating shaft 4 stops.

[0027] The electromagnet 28 is positioned within the stationary housing 12 so as to surround the first rotating plate 5 and the second rotating plate 6. The electromagnet 28 is located radially outward from the first rotating plate 5 and the second rotating plate 6. However, the position of the electromagnet 28 is not particularly limited, as long as the magnetic field generated by the electromagnet 28 acts on the MR fluid F between the first rotating plate 5 and the second rotating plate 6. In one embodiment, the electromagnet 28 may be located outward in the axial direction from the first rotating plate 5 and the second rotating plate 6. The electromagnet 28 is composed of a coil in which electric wires are wound around a core made of a magnetic material (for example, a metal such as electromagnetic steel) which has high permeability and low coercivity.

[0028] The current supply to the electromagnet 28 is started and stopped by the current supply device 30. The current supply device 30 is configured to control the magnitude and temporal change of the current supplied to the electromagnet 28. When the current supply device 30 supplies current to the electromagnet 28, the electromagnet 28 generates a magnetic field, and the MR fluid F present in the gap between the first rotating plate 5 and the second rotating plate 6 is placed within the magnetic field.

[0029] In this embodiment, the current supply device 30 is configured to supply current to the electromagnet 28 according to a preset current supply pattern. For example, the current supply device 30 can instantaneously connect the first rotating shaft 3 and the second rotating shaft 4 (the first rotating plate 5 and the second rotating plate 6) by instantaneously supplying the rated current to the electromagnet 28. In another example, the current supply device 30 can achieve a soft start by gradually increasing the current from zero to the rated current over a preset time. In yet another example, the current supply device 30 can create a semi-clutch state in which the rotational speed of the second rotating shaft 4 is lower than the rotational speed of the first rotating shaft 3 by supplying a current smaller than the rated current to the electromagnet 28.

[0030] In the embodiment shown in Figure 1, the MR fluid clutch 150 is formed by a stationary housing 12 and further comprises a medium chamber 25 filled with a medium L constituting the MR fluid F, and a filter device 40 positioned between the MR fluid chamber 20 and the medium chamber 25. Specifically, the filter device 40 is provided on a first connecting member 8 that separates the MR fluid chamber 20 and the medium chamber 25. The filter device 40 communicates with the MR fluid chamber 20 and the medium chamber 25, and the medium chamber 25 communicates with the MR fluid chamber 20 via the filter device 40. The filter device 40 is configured to allow the passage of the medium L without allowing magnetic particles in the MR fluid F to pass through. The medium L of the MR fluid F in the MR fluid chamber 20 flows into the medium chamber 25 through the filter device 40, and the medium L in the medium chamber 25 flows into the MR fluid chamber 20 through the filter device 40.

[0031] The MR fluid clutch 150 has an inlet 13 that communicates with the MR fluid chamber 20 and allows the medium L of the MR fluid F to flow in from outside the MR fluid clutch 150, and an outlet 14 that communicates with the MR fluid chamber 20 and allows the medium L of the MR fluid F to flow out to the outside of the MR fluid clutch 150. The medium chamber 25 communicates with the inlet 13 and the outlet 14. In this embodiment, the inlet 13 and the outlet 14 are provided in the stationary housing 12.

[0032] The MR fluid clutch system 100 comprises an MR fluid clutch 150, a medium tank 50 in which the medium L of the MR fluid F is stored, a medium circulation line 52 for circulating the medium L of the MR fluid F between the medium tank 50 and the MR fluid chamber 20 of the MR fluid clutch 150, and a pump 56 located in the medium circulation line 52. The medium circulation line 52 is piping that communicates with the medium chamber 25 through the inlet 13 and outlet 14 of the MR fluid clutch 150. The inlet 13 and outlet 14 are connected to the medium circulation line 52.

[0033] In this embodiment, two inlets 13 are provided along the axial direction, and two outlets 14 are provided along the axial direction. However, the number and position of the inlets 13 and outlets 14 are not particularly limited, as long as the medium L of the MR fluid F flows from the medium circulation line 52 into the medium chamber 25 through the inlets 13, and the medium L of the MR fluid F flows out from the medium chamber 25 into the medium circulation line 52 through the outlets 14.

[0034] Pump 56 is configured to send the medium L of the MR fluid F in the medium tank 50 to the medium chamber 25 through the medium circulation line 52. The specific configuration of pump 56 is not particularly limited, as long as it can circulate the medium L of the MR fluid F between the medium chamber 25 and the medium tank 50. In one embodiment, examples of pump 56 include reciprocating pumps, positive displacement pumps such as gear pumps, viscous pumps, centrifugal pumps, etc. Pump 56 is preferably a reciprocating pump using a piston, plunger, or diaphragm, and such a reciprocating pump can circulate a medium L with low viscosity even if some magnetic particles are present. Pump 56 may be a manual pump or an electric pump.

[0035] When the pump 56 is activated, the medium L circulates between the medium tank 50 and the medium chamber 25 through the medium circulation line 52. The medium L in the medium chamber 25 flows into the MR fluid chamber 20 through the filter device 40, and the medium L contained in the MR fluid F in the MR fluid chamber 20 flows out into the medium chamber 25 through the filter device 40 and is returned to the medium tank 50 through the medium circulation line 52. The movement of the medium L between the MR fluid chamber 20 and the medium chamber 25 is mainly caused by the expansion and contraction of the MR fluid F due to temperature changes. In this way, the medium L constituting the MR fluid F circulates between the MR fluid chamber 20 and the medium tank 50, while the magnetic particles contained in the MR fluid F remain in the MR fluid chamber 20. In one embodiment, the medium tank 50 may be configured to allow new medium L to be replenished in the medium tank 50.

[0036] In the MR fluid clutch 150 embodiment shown in Figure 1, the first rotating shaft 3, first rotating plate 5, and first connecting member 8 of the first shaft structure 1 are not in contact with the second rotating shaft 4, second rotating plate 6, and second connecting member 9 of the second shaft structure 2, and the first rotating shaft 3 can rotate independently of the second rotating shaft 4. Furthermore, the rotating elements, namely the first rotating shaft 3, first rotating plate 5, first connecting member 8, second rotating shaft 4, second rotating plate 6, and second connecting member 9, are not in contact with the stationary elements, namely the stationary housing 12 and electromagnet 28.

[0037] When the first rotating plate 5 and the second rotating plate 6 are rotating, the stationary housing 12 and the electromagnet 28 do not rotate. In other words, the rotating body, including the first rotating shaft 3, the first rotating plate 5, the first connecting member 8, the second rotating shaft 4, the second rotating plate 6, and the second connecting member 9, is rotatable relative to the stationary housing 12 and the electromagnet 28.

[0038] In the embodiment shown in Figure 1, the first rotating plate 5 and the second rotating plate 6 are located within the first connecting member 8. The first connecting member 8 has a circular axial connecting wall 8a extending radially outward from the first rotating shaft 3, a cylindrical outer peripheral wall 8b extending axially from the outer peripheral portion of the axial connecting wall 8a, a plate cover wall 8c extending radially inward from the outer peripheral wall 8b, and a cylindrical axial cover wall 8d extending from the inner peripheral portion of the plate cover wall 8c to surround the second rotating shaft 4. The first rotating plate 5 is fixed inside the outer peripheral wall 8b. The second connecting member 9 is a circular block fixed to the second rotating shaft 4. The second rotating plate 6 is fixed to the outer peripheral portion of the second connecting member 9.

[0039] The first bearing 15 is located between the first rotating shaft 3 and the stationary housing 12 and supports the first rotating shaft 3. The second bearing 16 is located between the second rotating shaft 4 and the stationary housing 12 and supports the second rotating shaft 4. The intermediate bearing 17 is located between the shaft cover wall 8d and the stationary housing 12 and supports the shaft cover wall 8d.

[0040] In the embodiment shown in Figure 1, a plurality of first rotating plates 5 and a plurality of second rotating plates 6 are provided, and the first rotating plates 5 and the second rotating plates 6 are arranged alternately along the axial direction. The gap between the first rotating plates 5 and the second rotating plates 6 is filled with MR fluid F. In one embodiment, one first rotating plate 5 and one second rotating plate 6 may be provided.

[0041] The MR fluid clutch 150 further includes a first sealing device 35 that seals the gap between the first shaft structure 1 and the second shaft structure 2, and a second sealing device 36 and a third sealing device 37 that seal the gap between the first shaft structure 1 and the stationary housing 12. More specifically, the first sealing device 35 is located between the shaft cover wall 8d of the first connecting member 8 and the second rotating shaft 4. The second sealing device 36 is located between the first rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the shaft cover wall 8d of the first connecting member 8 and the stationary housing 12. The specific configurations of the first sealing device 35, the second sealing device 36, and the third sealing device 37 are not particularly limited, but examples include oil seals (V-seals), mechanical seals, O-rings, gland packings, etc.

[0042] In the embodiment shown in Figure 1, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by a first connecting member 8, a second connecting member 9, a second rotating shaft 4, and a first sealing device 35. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0043] In the embodiment shown in Figure 1, the media chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second seal device 36, and a third seal device 37. More specifically, the media chamber 25 is formed by a stationary housing 12, a first rotating shaft 3, a first connecting member 8, a second seal device 36, and a third seal device 37. The first bearing 15 is positioned outside the second seal device 36 relative to the media chamber 25, and the intermediate bearing 17 is positioned outside the third seal device 37 relative to the media chamber 25.

[0044] The media circulation line 52 includes a media supply line 53 for supplying media L of MR fluid F from the media tank 50 to the MR fluid chamber 20 of the MR fluid clutch 150 via the media chamber 25, and a media return line 54 for returning media L of MR fluid F from the MR fluid chamber 20 of the MR fluid clutch 150 to the media tank 50 via the media chamber 25. One end of the media supply line 53 is connected to the media tank 50, and the other end is connected to the inlet 13 of the MR fluid clutch 150. One end of the media return line 54 is connected to the outlet 14 of the MR fluid clutch 150, and the other end is connected to the media tank 50. A pump 56 is located in the media supply line 53. In one embodiment, the media circulation line 52 may include a media discharge line (not shown) branching off from the media return line 54, and be configured to discharge old media L from the media discharge line.

[0045] The MR fluid clutch system 100 further includes a cooling device 58 for cooling the medium L of the MR fluid F flowing through the medium circulation line 52. The specific configuration of the cooling device 58 is not particularly limited, but in the embodiment shown in Figure 1, the cooling device 58 is a circulating cooling device connected to the medium tank 50. The cooling device 58 is configured to cool the medium L of the MR fluid F flowing through the medium circulation line 52 by lowering the temperature of the medium L in the medium tank 50. In one embodiment, the cooling device 58 may be connected to the medium circulation line 52.

[0046] In the MR fluid clutch 150 of this embodiment, the filter devices 40 are attached to the wall surface of the first connecting member 8 that forms the MR fluid chamber 20. More specifically, two filter devices 40 are attached to the shaft connecting wall 8a, and two filter devices 40 are attached to the plate cover wall 8c. The filter devices 40 are located near the first rotating plate 5 and the second rotating plate 6. However, the number and position of the filter devices 40 are not particularly limited, as long as the medium L of the MR fluid F in the MR fluid chamber 20 can flow into the medium chamber 25 through the filter devices 40, and the medium L in the medium chamber 25 can flow into the MR fluid chamber 20 through the filter devices 40.

[0047] Furthermore, considering maintenance and initial setup such as replacing the MR fluid F in the MR fluid chamber 20 or replacing the filter device 40, the position and opening diameter of the inlet 13 (or outlet 14) may be designed to allow for attachment and detachment of the filter device 40 from the wall surface of the first connecting member 8. The hole in the first connecting member 8 after the filter device 40 has been removed can be used as an outlet for the MR fluid F.

[0048] Figure 2(a) is an enlarged cross-sectional view showing one embodiment of the filter device 40 shown in Figure 1, and Figure 2(b) is a view from the direction indicated by arrow A in Figure 2(a). The filter device 40 shown in Figures 2(a) and 2(b) is a magnetic seal device configured to prevent the passage of magnetic particles by a magnetic field. The filter device 40 of this embodiment has a filter channel 42 that allows the passage of the medium L of the MR fluid F, two magnets 43 arranged around the filter channel 42, two spacers 44 arranged between the two magnets 43, and a filter casing 45 that surrounds the two magnets 43 and the two spacers 44.

[0049] The two magnets 43 are permanent magnets. Each of the two magnets 43 has a first pole 43a and a second pole 43b with different polarities. The second pole 43b is located on the opposite side from the plane on which the first pole 43a is located. In this embodiment, the first pole 43a is the north pole and the second pole 43b is the south pole. In one embodiment, the first pole 43a may be the south pole and the second pole 43b may be the north pole. The two magnets 43 facing each other in the filter casing 45 are arranged so that the first pole 43a and the second pole 43b face each other. The distance between the two magnets 43 is fixed by a spacer 44.

[0050] The two spacers 44 and the filter casing 45 are made of a non-magnetic material. The two magnets 43 and the two spacers 44 are mounted on the inner surface of the filter casing 45. The filter channel 42 is formed by the two magnets 43 and the two spacers 44. The dashed arrows in Figure 2(b) represent the magnetic field lines of the magnetic field generated by the two magnets 43. Due to the action of the magnetic field generated by the two magnets 43, magnetic particles contained in the MR fluid F in the MR fluid chamber 20 do not flow into the filter channel 42. On the other hand, the medium L of the MR fluid F in the MR fluid chamber 20 and the medium L in the medium chamber 25 can pass through the filter channel 42 and move back and forth between the MR fluid chamber 20 and the medium chamber 25.

[0051] In another embodiment of the filter device 40 shown in Figure 1, the filter device 40 has a filtration accuracy smaller than the particle size of the magnetic particles contained in the MR fluid F. "Filtration accuracy" refers to the size of the mesh (aperture) of the filter device. The filter device 40, having a filtration accuracy smaller than the particle size of the magnetic particles, allows the medium L to pass through without allowing the magnetic particles in the MR fluid F to pass through.

[0052] Although the first and second rotation axes 3 and 4 of the MR fluid clutch 150 shown in Figure 1 extend in the vertical direction, the orientation of the MR fluid clutch 150 is not limited to the vertical arrangement shown in Figure 1. For example, the MR fluid clutch 150 may be arranged horizontally or diagonally.

[0053] Figure 3 is a flowchart illustrating one embodiment of the operation of the MR fluid clutch system 100 shown in Figure 1. In step S101, the pump 56 is activated to circulate the medium L of the MR fluid F between the medium tank 50 and the medium chamber 25 through the medium circulation line 52. More specifically, when the pump 56 is activated, the medium L of the MR fluid F flows from the medium tank 50 into the medium chamber 25 through the medium supply line 53. The medium L in the medium chamber 25 flows into the MR fluid chamber 20 through the filter device 40. The medium L in the MR fluid chamber 20 flows into the medium chamber 25 through the filter device 40. The movement of the medium L between the MR fluid chamber 20 and the medium chamber 25 is mainly caused by the expansion and contraction due to temperature changes of the MR fluid F. The medium L in the medium chamber 25 is returned to the medium tank 50 through the medium return line 54. Thus, the medium L of the MR fluid F circulates between the medium tank 50 and the MR fluid chamber 20.

[0054] In step S102, the prime mover 60 is started to rotate the first rotating shaft 3. In one embodiment, step S102 may be performed after a sufficient flow of the medium L of the MR fluid F circulating between the medium tank 50 and the MR fluid chamber 20 has been established (after a predetermined time has elapsed since step S101).

[0055] In step S103, the current supply device 30 supplies current to the electromagnet 28, generating a magnetic field in the electromagnet 28. In one embodiment, the current supply device 30 supplies current to the electromagnet 28 according to a preset current supply pattern. The magnetic field increases the viscosity of the MR fluid F present between the first rotating plate 5 and the second rotating plate 6 (solidifying the MR fluid F). The increased viscosity of the MR fluid F connects the first rotating plate 5 and the second rotating plate 6. As a result, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate (step S104).

[0056] The operation from step S105 onward is the stopping operation of the MR fluid clutch system 100. In step S105, the operation of the prime mover 60 is stopped, and the rotation of the first rotating shaft 3 is stopped. This also stops the rotation of the load connected to the second rotating shaft 4. In step S106, the current supply to the electromagnet 28 by the current supply device 30 is stopped. The MR fluid F present between the first rotating plate 5 and the second rotating plate 6 returns to its original viscosity (liquefies), thereby releasing the connection between the first rotating plate 5 and the second rotating plate 6, and releasing the connection between the first rotating shaft 3 and the second rotating shaft 4. In one embodiment, steps S105 and S106 may be performed simultaneously, or step S105 may be performed after step S106.

[0057] In step S107, the pump 56 is stopped to cease the circulation of the medium L of the MR fluid F between the medium tank 50 and the medium chamber 25. In one embodiment, step S107 may be performed after the temperature of the medium L of the MR fluid F in the MR fluid chamber 20 has sufficiently decreased (after a predetermined time has elapsed since step S106).

[0058] According to this embodiment, by circulating the medium L of the MR fluid F between the MR fluid chamber 20 and the medium tank 50, the temperature rise of the MR fluid F in the MR fluid chamber 20 can be suppressed, and the thermal expansion of the MR fluid F can be absorbed. Furthermore, since the medium L of the MR fluid F is supplied to the MR fluid chamber 20 from the medium tank 50 through the medium circulation line 52, vaporization of the medium L of the MR fluid F in the MR fluid chamber 20 can be suppressed. As a result, the torque transmission performance of the MR fluid F can be stabilized, and leakage and deterioration of the MR fluid F can be prevented.

[0059] Furthermore, according to this embodiment, the cooling device 58 cools the medium L of the MR fluid F flowing through the medium circulation line 52, thereby suppressing the temperature rise of the MR fluid F.

[0060] Figure 4 is a cross-sectional view showing another embodiment of the MR fluid clutch system 100. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment shown in Figure 1, and therefore redundant descriptions are omitted. As shown in Figure 4, the MR fluid clutch system 100 of this embodiment further includes a torque transmission mechanism 63 that transmits the torque of the prime mover 60 to the pump 56. The torque transmission mechanism 63 is connected to the first rotating shaft 3 and the pump 56.

[0061] The torque transmission mechanism 63 of this embodiment includes a pulley 65 attached to the first rotating shaft 3, a pulley 66 attached to the pump rotating shaft 56a of the pump 56, and a belt 67 stretched over these pulleys 65 and 66. When the prime mover 60 is driven, the pump rotating shaft 56a of the pump 56 rotates via the pulleys 65 and 66 and the belt 67. However, the specific configuration of the torque transmission mechanism 63 is not particularly limited, as long as it can transmit the torque of the prime mover 60 to the pump 56. For example, the torque transmission mechanism 63 may be composed of multiple gears.

[0062] According to this embodiment, the pump 56 is operated in conjunction with the drive of the prime mover 60. Therefore, while the prime mover 60 is driven and the first rotating shaft 3 is rotating, the medium L of the MR fluid F can be circulated between the medium tank 50 and the MR fluid chamber 20 through the medium circulation line 52.

[0063] Figure 5 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100, and Figure 6 is a cross-sectional view taken along line BB of Figure 5. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment shown in Figure 1, so their redundant explanations are omitted. As shown in Figure 5, the first shaft structure 1 of this embodiment includes a first rotating shaft 3, first rotating plates 5A and 5B, and a first connecting member 8. The first rotating plate 5A extends radially outward from the first rotating shaft 3 and has a circular shape. The first connecting member 8 extends axially from the outer circumference of the first rotating plate 5A and has a cylindrical shape. The first rotating plate 5B extends radially inward from the first connecting member 8.

[0064] The first rotating plate 5A is fixed to the first rotating shaft 3, and the first rotating plate 5B is connected to the first rotating shaft 3 via the first connecting member 8 and the first rotating plate 5A. The first connecting member 8 is fixed to the first rotating plate 5A and the first rotating plate 5B. The first rotating shaft 3, the first rotating plates 5A and 5B, and the first connecting member 8 rotate together as the first rotating shaft 3 rotates. The filter device 40 is attached to the wall surface of the first connecting member 8 that forms the MR fluid chamber 20. As shown in Figure 6, in this embodiment, eight filter devices 40 are provided along the circumferential direction of the first connecting member 8.

[0065] The second axis structure 2 of this embodiment has a second rotating shaft 4 and a second rotating plate 6. The second rotating plate 6 is fixed to the second rotating shaft 4 and has a circular shape. The second rotating shaft 4 and the second rotating plate 6 rotate together as the second rotating shaft 4 rotates. In this embodiment, the first rotating plates 5A, 5B and the second rotating plate 6 are made of a magnetic material (for example, a metal such as electromagnetic steel), and the first connecting member 8 is made of a non-magnetic material.

[0066] In this embodiment, two first rotating plates 5A and 5B and one second rotating plate 6 are provided. The first rotating plates 5A and 5B are arranged in the order of first rotating plate 5A, first rotating plate 5B, from the side closer to the first rotation axis 3 in the axial direction. The second rotating plate 6 is positioned between the first rotating plate 5A and the first rotating plate 5B in the axial direction. The gaps between the first rotating plate 5A and the second rotating plate 6, and the gaps between the first rotating plate 5B and the second rotating plate 6 are filled with MR fluid F.

[0067] The first bearing 15 is located between the first rotating shaft 3 and the stationary housing 12 and supports the first rotating shaft 3. The second bearing 16 is located between the second rotating shaft 4 and the stationary housing 12 and supports the second rotating shaft 4. In this embodiment, an intermediate bearing 17 is not provided.

[0068] In this embodiment, the first sealing device 35 is located between the first rotating plate 5B and the second rotating shaft 4. The second sealing device 36 is located between the first rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the second rotating shaft 4 and the stationary housing 12.

[0069] In this embodiment, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by first rotating plates 5A, 5B, a first connecting member 8, a second rotating plate 6, a second rotating shaft 4, and a first sealing device 35. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0070] In this embodiment, the media chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second shaft structure 2, a first seal device 35, a second seal device 36, and a third seal device 37. More specifically, the media chamber 25 is formed by a stationary housing 12, a first rotating shaft 3, first rotating plates 5A, 5B, a first connecting member 8, a second rotating shaft 4, a first seal device 35, a second seal device 36, and a third seal device 37. The first bearing 15 is positioned outside the media chamber 25 beyond the second seal device 36, and the second bearing 16 is positioned outside the media chamber 25 beyond the third seal device 37.

[0071] In this embodiment, the MR fluid clutch 150 comprises four electromagnets 28 arranged in a medium chamber 25. Each of the four electromagnets 28 comprises a coil 70 and a magnetic member 71 around which the coil 70 is wound. The electromagnets 28 in this embodiment are U-shaped electromagnets. The magnetic member 71 is made of a magnetic material. The magnetic member 71 has a coil holding portion 71a located radially outward from the first rotating plates 5A, 5B and the second rotating plate 6, and a first wall portion 71b and a second wall portion 71c extending radially inward from the coil holding portion 71a. The coil 70 is wound around the coil holding portion 71a. The first wall portion 71b and the second wall portion 71c are arranged parallel to each other. The first rotating plates 5A, 5B and the second rotating plate 6 are arranged between the first wall portion 71b and the second wall portion 71c in the axial direction of the first rotating shaft 3 and the second rotating shaft 4. When current flows through the coil 70, a magnetic field is generated between the first wall portion 71b and the second wall portion 71c of the magnetic member 71.

[0072] In Figure 5, only two electromagnets 28 are depicted. As shown in Figure 6, four electromagnets 28 are arranged around the first rotating plates 5A, 5B and the second rotating plate 6. The electromagnets 28 are located radially outward from the first rotating plates 5A, 5B and the second rotating plate 6. However, the number and position of the electromagnets 28 are not particularly limited, as long as the magnetic field generated by the electromagnets 28 acts on the MR fluid F between the first rotating plates 5A, 5B and the second rotating plate 6. In one embodiment, the electromagnets 28 may be located outward in the axial direction from the first rotating plates 5A, 5B and the second rotating plate 6.

[0073] The four electromagnets 28 (four magnetic members 71) are each fixed to the stationary housing 12 via four fixing members 72. The electromagnets 28 (coils 70 and magnetic members 71) are not in contact with the first axial structure 1 and the second axial structure 2. In one embodiment, the magnetic members 71 and the fixing members 72 may be formed integrally.

[0074] When the current supply device 30 supplies current to the electromagnet 28 and a magnetic field is applied to the MR fluid F, the viscosity of the MR fluid F increases (the MR fluid F solidifies), and the first rotating plates 5A, 5B and the second rotating plate 6 are connected. When the first rotating plates 5A, 5B and the second rotating plate 6 are connected, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate. When the current supply device 30 stops supplying current to the electromagnet 28 and the application of a magnetic field to the MR fluid F stops, the MR fluid F returns to its original viscosity (liquefies), and the connection between the first rotating plates 5A, 5B and the second rotating plate 6 is released. When the connection between the first rotating plates 5A, 5B and the second rotating plate 6 is released, the transmission of the rotation (torque) of the first rotating shaft 3 to the second rotating shaft 4 stops, and the rotation of the load connected to the second rotating shaft 4 stops.

[0075] Figure 7 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100, and Figure 8 is a cross-sectional view taken along line CC of Figure 7. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiments shown in Figures 5 and 6, so their redundant descriptions are omitted. As shown in Figure 7, the first shaft structure 1 of this embodiment has a first rotating shaft 3, a first rotating plate 5, and a first connecting member 8. The first connecting member 8 has a circular shaft connecting wall 8a extending radially outward from the first rotating shaft 3, and a cylindrical outer peripheral wall 8b extending axially from the outer periphery of the shaft connecting wall 8a. The first rotating plate 5 is fixed to the first connecting member 8 and extends radially inward from the outer peripheral wall 8b. The first rotating shaft 3, the first rotating plate 5, and the first connecting member 8 rotate together with the rotation of the first rotating shaft 3. In this embodiment, the filter device 40 is attached to the wall surface of the first connecting member 8 that forms the MR fluid chamber 20. More specifically, the filter device 40 is attached to the axial connecting wall 8a. In one embodiment, the filter device 40 may be attached to the outer peripheral wall 8b.

[0076] The second axis structure 2 of this embodiment has a second rotating shaft 4 and second rotating plates 6A and 6B. The second rotating plates 6A and 6B are fixed to the second rotating shaft 4 and extend radially outward from the second rotating shaft 4. The second rotating shaft 4 and the second rotating plates 6A and 6B rotate together as the second rotating shaft 4 rotates. In this embodiment, the first rotating plate 5 and the second rotating plates 6A and 6B are made of a magnetic material (for example, a metal such as electromagnetic steel), and the first connecting member 8 is made of a non-magnetic material.

[0077] In this embodiment, one first rotating plate 5 and two second rotating plates 6A and 6B are provided. The second rotating plates 6A and 6B are arranged in the order of second rotating plate 6A, second rotating plate 6B, from the side closer to the first rotating axis 3 in the axial direction. The first rotating plate 5 is positioned between the second rotating plates 6A and 6B in the axial direction. The gaps between the second rotating plate 6A and the first rotating plate 5, and the gaps between the second rotating plate 6B and the first rotating plate 5 are filled with MR fluid F.

[0078] In this embodiment, the first sealing device 35 is located between the first rotating plate 5 and the second rotating plate 6B. The second sealing device 36 is located between the first rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the second rotating shaft 4 and the stationary housing 12.

[0079] The electromagnet 28 in this embodiment has an annular shape and is arranged to surround the second rotation axis 4. The electromagnet 28 is positioned between the second rotation plate 6A and the second rotation plate 6B and is located radially inward of the first rotation plate 5. The electromagnet 28 is supported by an annular electromagnet support member 73 and is fixed to the second rotation axis 4 via the electromagnet support member 73. The electromagnet 28 rotates integrally with the second axis structure 2 as the second rotation axis 4 rotates. The electromagnet 28 is non-contact with the first axis structure 1. In this embodiment, the electromagnet support member 73 is made of a magnetic material. The electromagnet 28 in this embodiment is connected to the current supply device 30 by a brush electrode 75. In one embodiment, the second rotation plates 6A, 6B and the electromagnet support member 73 are formed integrally, and the electromagnet support member 73 may be included in the second axis structure 2.

[0080] In this embodiment, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, an electromagnet 28, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by a first rotating plate 5, a first connecting member 8, second rotating plates 6A, 6B, an electromagnet 28, and a first sealing device 35. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0081] In this embodiment, the medium chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second shaft structure 2, a first sealing device 35, a second sealing device 36, and a third sealing device 37. More specifically, the medium chamber 25 is formed by a stationary housing 12, a first rotating shaft 3, a first connecting member 8, a first rotating plate 5, a second rotating shaft 4, a second rotating plate 6B, a first sealing device 35, a second sealing device 36, and a third sealing device 37.

[0082] When the current supply device 30 supplies current to the electromagnet 28 and a magnetic field is applied to the MR fluid F, the viscosity of the MR fluid F increases (the MR fluid F solidifies), and the first rotating plate 5 and the second rotating plates 6A and 6B are connected. When the first rotating plate 5 and the second rotating plates 6A and 6B are connected, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate. When the current supply device 30 stops supplying current to the electromagnet 28 and the application of the magnetic field to the MR fluid F stops, the MR fluid F returns to its original viscosity (liquefies), and the connection between the first rotating plate 5 and the second rotating plates 6A and 6B is released. When the connection between the first rotating plate 5 and the second rotating plates 6A and 6B is released, the transmission of the rotation (torque) of the first rotating shaft 3 to the second rotating shaft 4 stops, and the rotation of the load connected to the second rotating shaft 4 stops.

[0083] Figure 9 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiments shown in Figures 5 and 6, and therefore the redundant description is omitted. As shown in Figure 9, the first shaft structure 1 of this embodiment has a first rotating shaft 3, first rotating plates 5A, 5B, 5C, 5D, 5E, and a first connecting member 8. The first rotating plate 5A extends radially outward from the first rotating shaft 3 and has a circular shape. The first connecting member 8 extends axially from the outer circumference of the first rotating plate 5A and has a cylindrical shape. The first rotating plates 5B, 5C, 5D, 5E extend radially inward from the first connecting member 8.

[0084] The first rotating plate 5A is fixed to the first rotating shaft 3, and the first rotating plates 5B, 5C, 5D, and 5E are connected to the first rotating shaft 3 via the first connecting member 8 and the first rotating plate 5A. The first connecting member 8 is fixed to the first rotating plates 5A to 5E. The first rotating shaft 3, the first rotating plates 5A to 5E, and the first connecting member 8 rotate together as the first rotating shaft 3 rotates. The filter device 40 is attached to the wall surface of the first connecting member 8 which forms the MR fluid chamber 20.

[0085] The second axis structure 2 of this embodiment has a second rotating shaft 4 and second rotating plates 6A, 6B, 6C, and 6D. The second rotating plate 6A is connected to the end of the second rotating shaft 4 and has a circular shape. The second rotating plates 6B to 6D extend radially outward from the second rotating shaft 4. The second rotating plates 6A to 6D are fixed to the second rotating shaft 4, and the second rotating shaft 4 and the second rotating plates 6A to 6D rotate together as the second rotating shaft 4 rotates. In this embodiment, the first rotating plates 5A to 5E and the second rotating plates 6A to 6D are made of a magnetic material (for example, a metal such as electromagnetic steel), and the first connecting member 8 is made of a non-magnetic material.

[0086] In this embodiment, five first rotating plates 5A to 5E and four second rotating plates 6A to 6D are provided. The five first rotating plates 5A to 5E are arranged in the order of 5A, 5B, 5C, 5D, and 5E from the side closest to the first rotation axis 3 in the axial direction. The four second rotating plates 6A to 6D are arranged in the order of 6A, 6B, 6C, and 6D from the side closest to the first rotation axis 3 in the axial direction. Second rotating plate 6A is positioned between first rotating plate 5A and first rotating plate 5B in the axial direction. Second rotating plate 6B is positioned between first rotating plate 5B and first rotating plate 5C in the axial direction. Second rotating plate 6C is positioned between first rotating plate 5C and first rotating plate 5D in the axial direction. Second rotating plate 6D is positioned between first rotating plate 5D and first rotating plate 5E in the axial direction.

[0087] The gaps between the first rotating plate 5A and the second rotating plate 6A, the gaps between the first rotating plate 5B and the second rotating plates 6A and 6B, the gaps between the first rotating plate 5C and the second rotating plates 6B and 6C, the gaps between the first rotating plate 5D and the second rotating plates 6C and 6D, and the gaps between the first rotating plate 5E and the second rotating plate 6D are filled with MR fluid F.

[0088] In this embodiment, the first sealing device 35 is located between the first rotating plate 5E and the second rotating shaft 4. The second sealing device 36 is located between the first rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the second rotating shaft 4 and the stationary housing 12.

[0089] In this embodiment, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by first rotating plates 5A to 5E, a first connecting member 8, second rotating plates 6A to 6D, a second rotating shaft 4, and a first sealing device 35. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0090] In this embodiment, the media chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second shaft structure 2, a first sealing device 35, a second sealing device 36, and a third sealing device 37. More specifically, the media chamber 25 is formed by a stationary housing 12, a first rotating shaft 3, first rotating plates 5A, 5E, a first connecting member 8, a second rotating shaft 4, a first sealing device 35, a second sealing device 36, and a third sealing device 37.

[0091] In this embodiment, four electromagnets (U-shaped electromagnets) 28 are arranged around the first rotating plates 5A-5E and the second rotating plates 6A-6D. These electromagnets 28 are located radially outward from the first rotating plates 5A-5E and the second rotating plates 6A-6D. The first rotating plates 5A-5E and the second rotating plates 6A-6D are positioned between the first wall portion 71b and the second wall portion 71c in the axial direction of the first rotation axis 3 and the second rotation axis 4. However, the number and position of the electromagnets 28 are not particularly limited, as long as the magnetic field generated by the electromagnets 28 acts on the MR fluid F between the first rotating plates 5A-5E and the second rotating plates 6A-6D. In one embodiment, the electromagnets 28 may be located outward in the axial direction from the first rotating plates 5A-5E and the second rotating plates 6A-6D.

[0092] When the current supply device 30 supplies current to the electromagnet 28 and a magnetic field is applied to the MR fluid F, the viscosity of the MR fluid F increases (the MR fluid F solidifies), and the first rotating plates 5A-5E and the second rotating plates 6A-6D are connected. When the first rotating plates 5A-5E and the second rotating plates 6A-6D are connected, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate. When the current supply device 30 stops supplying current to the electromagnet 28 and the application of a magnetic field to the MR fluid F stops, the MR fluid F returns to its original viscosity (liquefies), and the connection between the first rotating plates 5A-5E and the second rotating plates 6A-6D is released. When the connection between the first rotating plates 5A-5E and the second rotating plates 6A-6D is released, the transmission of rotation (torque) from the first rotating shaft 3 to the second rotating shaft 4 is stopped, and the rotation of the load connected to the second rotating shaft 4 stops.

[0093] Figure 10 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100, and Figure 11 is a cross-sectional view of Figure 10 along the line DD. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiments shown in Figures 5 and 6, and therefore their redundant descriptions are omitted. As shown in Figure 10, the first shaft structure 1 of this embodiment includes a first rotating shaft 3, first rotating plates 5A, 5B, and first connecting members 8E, 8F, 8G. The first connecting member 8E extends radially outward from the first rotating shaft 3 and has a circular shape. The first rotating plate 5A extends axially from the outer circumference of the first connecting member 8E and has a cylindrical shape. The first connecting member 8F extends radially inward from the first rotating plate 5A. The first rotating plate 5B extends axially from the inner circumference of the first connecting member 8F and has a cylindrical shape. The first connecting member 8G extends radially inward from the first rotating plate 5B.

[0094] The first rotating plate 5A is connected to the first rotating shaft 3 via the first connecting member 8E, and the first rotating plate 5B is connected to the first rotating shaft 3 via the first connecting member 8F, the first rotating plate 5A, and the first connecting member 8E. The first connecting member 8E is fixed to the first rotating plate 5A, the first connecting member 8F is fixed to the first rotating plates 5A and 5B, and the first connecting member 8G is fixed to the first rotating plate 5B. The first rotating shaft 3, the first rotating plates 5A and 5B, and the first connecting members 8E to 8G rotate together as the first rotating shaft 3 rotates. In this embodiment, the filter device 40 is attached to the walls of the first connecting members 8E and 8F that form the MR fluid chamber 20. In one embodiment, the filter device 40 may be attached to the first connecting member 8G.

[0095] The second axis structure 2 of this embodiment includes a second rotation shaft 4, a second rotation plate 6, and a second connecting member 9. The second connecting member 9 is fixed to the second rotation shaft 4 and has a circular shape. The second rotation plate 6 extends axially from the outer circumference of the second connecting member 9 and has a cylindrical shape. The second rotation plate 6 is connected to the second rotation shaft 4 via the second connecting member 9. The second connecting member 9 is fixed to the second rotation plate 6. The second rotation shaft 4, the second rotation plate 6, and the second connecting member 9 rotate together as the second rotation shaft 4 rotates. In this embodiment, the first rotation plates 5A, 5B and the second rotation plate 6 are made of a magnetic material (for example, a metal such as electromagnetic steel), and the first connecting members 8E to 8G and the second connecting member 9 are made of a non-magnetic material.

[0096] In this embodiment, two first rotating plates 5A and 5B and one second rotating plate 6 are provided. The MR fluid clutch 150 of this embodiment is a cylindrical type MR fluid clutch equipped with cylindrical first rotating plates 5A and 5B and a second rotating plate 6. The first rotating plates 5A and 5B are arranged in the order of first rotating plate 5B, first rotating plate 5A, from the side closer to the first rotating shaft 3 and second rotating shaft 4 in the radial direction. The second rotating plate 6 is positioned radially between the first rotating plate 5A and the first rotating plate 5B. The gaps between the first rotating plate 5A and the second rotating plate 6, and the gaps between the first rotating plate 5B and the second rotating plate 6 are filled with MR fluid F.

[0097] In this embodiment, the first sealing device 35 is located between the first connecting member 8G and the second rotating shaft 4. The second sealing device 36 is located between the first rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the second rotating shaft 4 and the stationary housing 12.

[0098] In this embodiment, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by first rotating plates 5A, 5B, first connecting members 8E~8G, a second rotating plate 6, a second connecting member 9, a second rotating shaft 4, and a first sealing device 35. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0099] In this embodiment, the media chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second shaft structure 2, a first sealing device 35, a second sealing device 36, and a third sealing device 37. More specifically, the media chamber 25 is formed by a stationary housing 12, a first rotating shaft 3, first rotating plates 5A, 5B, first connecting members 8E to 8G, a second rotating shaft 4, a first sealing device 35, a second sealing device 36, and a third sealing device 37.

[0100] In this embodiment, four electromagnets (U-shaped electromagnets) 28 are arranged around the first rotating plates 5A, 5B and the second rotating plate 6. These electromagnets 28 are located in the axial direction between the first rotating plates 5A, 5B and the second rotating plate 6 and the stationary housing 12. Each of the four electromagnets 28 comprises a coil 70 and a magnetic member 71 around which the coil 70 is wound. The first rotating plates 5A, 5B and the second rotating plate 6 are positioned between the first wall portion 71b and the second wall portion 71c of the magnetic member 71 in the radial direction of the first rotation axis 3 and the second rotation axis 4. However, the number and position of the electromagnets 28 are not particularly limited, as long as the magnetic field generated by the electromagnets 28 acts on the MR fluid F between the first rotating plates 5A, 5B and the second rotating plate 6. In one embodiment, the electromagnets 28 may be located in the radial direction between the first rotating plates 5A, 5B and the second rotating plate 6 and the stationary housing 12.

[0101] The four electromagnets 28 (four magnetic members 71) are each fixed to the stationary housing 12 via four fixing members 72. The electromagnets 28 (coils 70 and magnetic members 71) are not in contact with the first axial structure 1 and the second axial structure 2. In one embodiment, the magnetic members 71 and the fixing members 72 may be formed integrally.

[0102] When the current supply device 30 supplies current to the electromagnet 28 and a magnetic field is applied to the MR fluid F, the viscosity of the MR fluid F increases (the MR fluid F solidifies), and the first rotating plates 5A, 5B and the second rotating plate 6 are connected. When the first rotating plates 5A, 5B and the second rotating plate 6 are connected, the rotation (torque) of the first rotating shaft 3 is transmitted to the second rotating shaft 4, causing the load connected to the second rotating shaft 4 to rotate. When the current supply device 30 stops supplying current to the electromagnet 28 and the application of a magnetic field to the MR fluid F stops, the MR fluid F returns to its original viscosity (liquefies), and the connection between the first rotating plates 5A, 5B and the second rotating plate 6 is released. When the connection between the first rotating plates 5A, 5B and the second rotating plate 6 is released, the transmission of the rotation (torque) of the first rotating shaft 3 to the second rotating shaft 4 stops, and the rotation of the load connected to the second rotating shaft 4 stops.

[0103] Each embodiment shown in Figures 5 to 11 can be combined with the embodiment shown in Figure 4. For example, the configuration of the torque transmission mechanism 63 shown in Figure 4 may be applied to the MR fluid clutch system 100 shown in Figure 5.

[0104] Figure 12 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment shown in Figure 1, so a redundant explanation is omitted. As shown in Figure 12, in this embodiment, a first internal shaft flow path 80 is formed inside the first rotating shaft 3, and a second internal shaft flow path 82 is formed inside the second rotating shaft 4.

[0105] The MR fluid clutch 150 of this embodiment includes a first filter device 40A connected to a medium supply line 53 and a second filter device 40B connected to a medium return line 54, instead of the filter device 40. The first filter device 40A covers the outer end of the first internal shaft flow path 80, and the second filter device 40B covers the outer end of the second internal shaft flow path 82. The configuration of the first filter device 40A and the second filter device 40B is the same as that of the filter device 40 in the embodiment shown in Figure 1. That is, in one embodiment, the first filter device 40A and the second filter device 40B are filter devices (magnetic seal devices) described with reference to Figures 2(a) and 2(b). In another embodiment, the first filter device 40A and the second filter device 40B have a filtration accuracy smaller than the particle size of the magnetic particles contained in the MR fluid F.

[0106] The first internal shaft channel 80 extends through the first rotating shaft 3 in the axial direction. The first internal shaft channel 80 communicates with the MR fluid chamber 20 at one end of the first rotating shaft 3, and further communicates with the medium supply line 53 through the first filter device 40A located at the other end of the first rotating shaft 3. In this embodiment, the inlet 13 is formed by the end of the first internal shaft channel 80 to which the first filter device 40A is connected. The inlet 13 communicates with the MR fluid chamber 20 via the first internal shaft channel 80. The second internal shaft channel 82 extends through the second rotating shaft 4 in the axial direction. The second internal shaft channel 82 communicates with the MR fluid chamber 20 at one end of the second rotating shaft 4, and further communicates with the medium return line 54 through the second filter device 40B located at the other end of the second rotating shaft 4. In this embodiment, the outlet 14 is formed by the end of the second internal shaft channel 82 to which the second filter device 40B is connected. The outlet 14 is in communication with the MR fluid chamber 20 via the second axial internal flow path 82.

[0107] The MR fluid clutch 150 of this embodiment does not include a medium chamber 25, a second sealing device 36, and a third sealing device 37.

[0108] When the pump 56 is activated, the medium L of the MR fluid F flows from the medium tank 50 through the medium supply line 53 and the first filter device 40A into the first in-shaft channel 80 from the inlet 13. The MR fluid F in the first in-shaft channel 80 flows into the MR fluid chamber 20. The medium L of the MR fluid F that flows from the MR fluid chamber 20 into the second in-shaft channel 82 is returned to the medium tank 50 from the outlet 14 through the second filter device 40B and the medium return line 54. In this way, the medium L of the MR fluid F circulates between the medium tank 50 and the MR fluid chamber 20.

[0109] In this embodiment, the connection between the first shaft internal flow path 80 and the medium supply line 53 is located at the end of the first rotating shaft 3; therefore, the prime mover 60 is not connected to the end of the first rotating shaft 3. The MR fluid clutch system 100 of this embodiment includes a prime mover 60 and a first rotating mechanism 85 connected to the first rotating shaft 3. The first rotating mechanism 85 includes a pulley 87 attached to the first rotating shaft 3, a pulley 88 attached to the prime mover rotating shaft 60a of the prime mover 60, and a belt 89 stretched over these pulleys 87 and 88. When the prime mover 60 is driven, the first rotating shaft 3 rotates via the pulleys 87 and 88 and the belt 89. The specific configuration of the first rotating mechanism 85 is not particularly limited, as long as the prime mover 60 can rotate the first rotating shaft 3 via the first rotating mechanism 85.

[0110] Similarly, since the connection between the second shaft internal flow path 82 and the medium return line 54 is located at the end of the second rotating shaft 4, loads such as impellers are not connected to the end of the second rotating shaft 4. The MR fluid clutch system 100 of this embodiment includes an impeller 110 as an example of a load and a second rotating mechanism 90 connected to the second rotating shaft 4. The second rotating mechanism 90 includes a pulley 92 attached to the second rotating shaft 4, a pulley 93 attached to a rotating shaft 105 fixed to the impeller 110, and a belt 94 stretched over these pulleys 92 and 93. When the second rotating shaft 4 rotates, the rotating shaft 105 and the impeller 110 rotate via the pulleys 92 and 93 and the belt 94. The specific configuration of the second rotating mechanism 90 is not particularly limited, as long as the second rotating shaft 4 can rotate the rotating shaft 105 and the impeller 110 via the second rotating mechanism 90.

[0111] The embodiment shown in Figure 12 can be combined with the embodiments shown in Figures 5 to 11. For example, the MR fluid clutch 150 shown in Figure 5 may be configured with the first rotating shaft 3 having the first internal flow path 80, the second rotating shaft 4 having the second internal flow path 82, the first rotating mechanism 85, and the second rotating mechanism 90 shown in Figure 12.

[0112] Figure 13 is a cross-sectional view showing yet another embodiment of the MR fluid clutch system 100. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment shown in Figure 12, and therefore redundant descriptions are omitted. As shown in Figure 13, in this embodiment, the prime mover 60 is connected to the end of the first rotating shaft 3, and loads such as the impeller 110 are connected to the end of the second rotating shaft 4.

[0113] The MR fluid clutch 150 of this embodiment includes a first seal case 96 surrounding the outer circumference of the first rotating shaft 3 and a second seal case 97 surrounding the outer circumference of the second rotating shaft 4. In this embodiment, the first internal shaft passage 80 does not penetrate the first rotating shaft 3, and the end of the first internal shaft passage 80 on the prime mover 60 side is closed. The second internal shaft passage 82 does not penetrate the second rotating shaft 4, and the end of the second internal shaft passage 82 on the impeller 110 side is closed. The first internal shaft passage 80 communicates with the seal chamber 96a in the first seal case 96 through an opening 3a formed on the outer circumferential surface of the first rotating shaft 3. The second internal shaft passage 82 communicates with the seal chamber 97a in the second seal case 97 through an opening 4a formed on the outer circumferential surface of the second rotating shaft 4. The seal chamber 96a in the first seal case 96 and the seal chamber 97a in the second seal case 97 are filled with MR fluid F.

[0114] The seal chamber 96a in the first seal case 96 is formed by the inner surface of the first seal case 96 and the outer surface of the first rotating shaft 3. In this embodiment, the inlet 13 is provided in the first seal case 96. The inlet 13 is formed in the outer peripheral wall of the first seal case 96. The first seal case 96 is connected to the medium supply line 53 through the inlet 13. The inlet 13 communicates with the MR fluid chamber 20 via the seal chamber 96a and the first internal shaft flow path 80. The seal chamber 97a in the second seal case 97 is formed by the inner surface of the second seal case 97 and the outer surface of the second rotating shaft 4. In this embodiment, the outlet 14 is provided in the second seal case 97. The outlet 14 is formed in the outer peripheral wall of the second seal case 97. The second seal case 97 is connected to the medium return line 54 through the outlet 14. The outlet 14 communicates with the MR fluid chamber 20 via the seal chamber 97a and the second internal shaft flow path 82. The first filter device 40A covers the inlet 13, and the second filter device 40B covers the outlet 14.

[0115] The MR fluid clutch 150 of this embodiment further includes a case seal device 99A that seals the gap between the first rotating shaft 3 and the first seal case 96, and a case seal device 99B that seals the gap between the second rotating shaft 4 and the second seal case 97. The specific configurations of the case seal devices 99A and 99B are not particularly limited, but examples include oil seals (V-seals), mechanical seals, O-rings, gland packings, etc.

[0116] The first seal case 96 is a fixed-side element that does not rotate even when the first axial structure 1 (first rotation axis 3) rotates. The second seal case 97 is a fixed-side element that does not rotate even when the second axial structure 2 (second rotation axis 4) rotates.

[0117] When the pump 56 is activated, the medium L of the MR fluid F flows from the medium tank 50 through the medium supply line 53 and the first filter device 40A into the seal chamber 96a in the first seal case 96 via the inlet 13. The MR fluid F in the first seal case 96 flows into the first internal shaft flow path 80 via the opening 3a. The MR fluid F in the first internal shaft flow path 80 flows into the MR fluid chamber 20 and then into the second internal shaft flow path 82. The MR fluid F in the second internal shaft flow path 82 flows into the seal chamber 97a in the second seal case 97 via the opening 4a. The medium L of the MR fluid F in the second seal case 97 is returned to the medium tank 50 via the outlet 14 through the second filter device 40B and the medium return line 54. Thus, the medium L of the MR fluid F circulates between the medium tank 50 and the MR fluid chamber 20.

[0118] The embodiment shown in Figure 13 can be combined with the embodiments shown in Figures 5 to 11. For example, the MR fluid clutch 150 shown in Figure 5 may be fitted with the configuration of the first rotating shaft 3 having the first internal flow path 80, the second rotating shaft 4 having the second internal flow path 82, the first seal case 96, and the second seal case 97 shown in Figure 13.

[0119] Figure 14 is a cross-sectional view showing one embodiment of the MR fluid brake system 200. The MR fluid brake (magnetorheological fluid brake) system 200 of this embodiment includes an MR fluid brake 250 (magnetorheological fluid brake), a media circulation line 52 connected to the MR fluid clutch 250, a media tank 50 storing the media L of the MR fluid F, and a pump 56 located in the media circulation line 52. The MR fluid brake 250 of this embodiment differs from the MR fluid clutch 150 shown in Figure 1 in the configuration of the second shaft structure 2. The configuration and operation of the MR fluid brake system 200 of this embodiment, which will not be specifically described, are the same as those of the MR fluid clutch system 100 shown in Figure 1, so a redundant explanation will be omitted.

[0120] The second shaft structure 2 of this embodiment includes a fixed shaft 201, a stationary plate 203, and a second connecting member 9. The end of the fixed shaft 201 is fixed to the stationary housing 12. The second shaft structure 2 of this embodiment is a fixed-side element. In this embodiment, the first rotating shaft 3 and the first rotating plate 5 of the first shaft structure 1 are simply referred to as the rotating shaft 3 and the rotating plate 5. In this embodiment, the second bearing 16 is not provided.

[0121] The rotating shaft 3 and the stationary shaft 201 are aligned in a straight line. In the embodiment shown in Figure 14, the rotating shaft 3, rotating plate 5, and first connecting member 8 of the first axial structure 1 are not in contact with the stationary shaft 201, stationary plate 203, and second connecting member 9 of the second axial structure 2. When the rotating plate 5 is rotating, the stationary shaft 201, stationary plate 203, stationary housing 12, and electromagnet 28 do not rotate. In other words, the rotating body including the rotating shaft 3, rotating plate 5, and first connecting member 8 is rotatable relative to the stationary shaft 201, stationary plate 203, stationary housing 12, and electromagnet 28. In this embodiment, the rotating plate 5 and stationary plate 203 are made of a magnetic material (e.g., a metal such as electromagnetic steel). In this embodiment, the rotating shaft 3 and the stationary shaft 201 are made of a non-magnetic metallic material.

[0122] The rotating plate 5 and the stationary plate 203 are located within the first connecting member 8. The second connecting member 9 is fixed to the fixed shaft 201. The stationary plate 203 is fixed to the outer circumference of the second connecting member 9. In this embodiment, a plurality of rotating plates 5 and a plurality of stationary plates 203 are provided, and the rotating plates 5 and stationary plates 203 are arranged alternately along the axial direction. The gap between the rotating plates 5 and the stationary plates 203 is filled with MR fluid F. In one embodiment, one rotating plate 5 and one stationary plate 203 may be provided.

[0123] In this embodiment, the first sealing device 35 is located between the shaft cover wall 8d of the first connecting member 8 and the fixed shaft 201. The second sealing device 36 is located between the rotating shaft 3 and the stationary housing 12. The third sealing device 37 is located between the shaft cover wall 8d of the first connecting member 8 and the stationary housing 12.

[0124] In this embodiment, the MR fluid chamber 20 is formed by a first shaft structure 1, a second shaft structure 2, and a first sealing device 35. More specifically, the MR fluid chamber 20 is formed by a first connecting member 8, a second connecting member 9, a fixed shaft 201, and a first sealing device 35. The gap between the rotating plate 5 and the stationary plate 203 is located within the MR fluid chamber 20. The MR fluid chamber 20 is sealed by the first sealing device 35 to prevent the MR fluid F from leaking out of the MR fluid chamber 20.

[0125] In this embodiment, the medium chamber 25 is formed by a stationary housing 12, a first shaft structure 1, a second sealing device 36, and a third sealing device 37. More specifically, the medium chamber 25 is formed by a stationary housing 12, a rotating shaft 3, a first connecting member 8, a second sealing device 36, and a third sealing device 37.

[0126] The electromagnet 28 is positioned within the stationary housing 12 so as to surround the rotating plate 5 and the stationary plate 203. When the current supply device 30 supplies current to the electromagnet 28 and a magnetic field is applied to the MR fluid F, the viscosity of the MR fluid F increases (the MR fluid F solidifies), and the rotating plate 5 and the stationary plate 203 become connected. When the rotating plate 5 and the stationary plate 203 are connected, a braking force is applied to the rotating plate 5, and the rotation of the rotating shaft 3 stops. When the current supply device 30 stops supplying current to the electromagnet 28 and the application of a magnetic field to the MR fluid F stops, the MR fluid F returns to its original viscosity (liquefies), and the connection between the rotating plate 5 and the stationary plate 203 is released. When the connection between the rotating plate 5 and the stationary plate 203 is released, the braking force applied to the rotating plate 5 is released, and the rotating shaft 3 becomes rotatable.

[0127] In the MR fluid brake system 200 shown in Figure 14, the temperature rise of the MR fluid F can be suppressed by circulating the MR fluid F between the MR fluid chamber 20 and the medium tank 50. Specifically, even if the temperature of the MR fluid F in the MR fluid chamber 20 of the MR fluid brake 250 rises, the medium L of the MR fluid F circulates through the MR fluid chamber 20, the medium chamber 25, the medium circulation line 52, and the medium tank 50, thereby suppressing the temperature rise of the MR fluid F in the MR fluid chamber 20 and absorbing the thermal expansion of the MR fluid F. Furthermore, since the medium L of the MR fluid F in the medium tank 50 is supplied to the MR fluid chamber 20 through the medium circulation line 52, vaporization of the medium L of the MR fluid F in the MR fluid chamber 20 can be suppressed. As a result, the torque transmission performance of the MR fluid F can be stabilized, and leakage and deterioration of the MR fluid F can be prevented.

[0128] Furthermore, according to this embodiment, the cooling device 58 cools the medium L of the MR fluid F flowing through the medium circulation line 52, thereby suppressing the temperature rise of the MR fluid F.

[0129] The embodiment shown in Figure 14 can be combined with the embodiments shown in Figures 4 to 13. For example, the configuration of the torque transmission mechanism 63 shown in Figure 4 may be applied to the MR fluid brake system 200 shown in Figure 14. In another example, the configuration of the MR fluid brake 250 shown in Figure 14 may be applied to the MR fluid brake 250 shown in Figure 14, which includes a first rotating shaft 3 having a first internal flow path 80, a second rotating shaft 4 having a second internal flow path 82, and a first rotating mechanism 85. In this case, the first internal flow path 80 is provided on the rotating shaft 3, the second internal flow path 82 is provided on the fixed shaft 201, and the first rotating mechanism 85 is connected to the rotating shaft 3. In yet another example, the configuration of the MR fluid brake 250 shown in Figure 14 may be applied to the MR fluid brake 250, which includes a first rotating shaft 3 having a first internal flow path 80, a second rotating shaft 4 having a second internal flow path 82, and a first seal case 96. In this case, the first internal shaft passage 80 is provided on the rotating shaft 3, the second internal shaft passage 82 is provided on the fixed shaft 201, and the first seal case 96 is provided so as to surround the outer circumference of the rotating shaft 3.

[0130] The MR fluid clutch system 100 and the MR fluid brake system 200, as described with reference to Figures 1 to 13 and 14 respectively, are suitably used in rotating machinery such as liquid pump devices. For example, the MR fluid clutch system 100 can be incorporated into vertical shaft pump devices installed in rivers, descaling pump devices used in steel mills, and so on. Descaling pump devices are configured to instantaneously switch between high-pressure liquid injection and injection stoppage, and the MR fluid clutch system 100 is suitably used for such operations. Furthermore, the MR fluid clutch system 100 can also be used as a reverse rotation prevention clutch for large pumps.

[0131] Figure 15 is a schematic diagram showing a pumping system comprising a vertical shaft pump device 300 incorporating one of the MR fluid clutch systems 100 described with reference to Figures 1 to 13. As shown in Figure 15, the pumping system comprises a vertical shaft pump device 300 incorporating one of the MR fluid clutch systems 100 described with reference to Figures 1 to 13, and a prime mover 60 for driving the vertical shaft pump device 300. The vertical shaft pump device 300 of this embodiment comprises a rotating shaft 105 extending vertically, an impeller 110 fixed to the rotating shaft 105, a pump casing 301 housing the impeller 110, a water lifting pipe 303 connected to the upper end of the pump casing 301, a discharge bend pipe 305 connected to the upper end of the water lifting pipe 303, a discharge pipe 308 connected to the discharge end of the discharge bend pipe 305, a discharge valve 331 attached to the discharge pipe 308, and a backflow prevention valve 332 attached to the discharge port of the discharge pipe 308.

[0132] The rotating shaft 105 is connected to the motor rotating shaft 60a of the prime mover 60 by an MR fluid clutch 150. One of the first rotating shaft 3 and the second rotating shaft 4 (see Figure 1) of the MR fluid clutch 150 is connected to the prime mover rotating shaft 60a, and the other of the first rotating shaft 3 and the second rotating shaft 4 is connected to the rotating shaft 105. Examples of prime movers 60 include electric motors, diesel engines, and gas turbine engines. The stationary housing 12 of the prime mover 60 and the MR fluid clutch 150 is fixed to a bracket 310. The prime mover rotating shaft 60a and the first rotating shaft 3 or the second rotating shaft 4 connected to the prime mover rotating shaft 60a may be configured as a single unit. The rotating shaft 105 and the first rotating shaft 3 or the second rotating shaft 4 connected to the rotating shaft 105 may be configured as a single unit. In one embodiment, a reduction gear may be provided between the MR fluid clutch 150 and the rotating shaft 105.

[0133] The pump casing 301 is suspended in the suction tank 350 by a water lifting pipe 303. The pump casing 301 comprises a suction bell mouth 312 and a discharge bowl 314. The upper end of the discharge bowl 314 is connected to the lower end of the water lifting pipe 303. The suction bell mouth 312 has a downward-opening suction port 312a, and the upper end of the suction bell mouth 312 is connected to the lower end of the discharge bowl 314. The suction port 312a is formed at the lower end of the pump casing 301. The impeller 110 is housed inside the pump casing 301.

[0134] The water lifting pipe 303 extends downward through an opening 355 formed in the pump mounting floor 352, which constitutes the upper wall of the suction tank 350. A mounting flange 318 is fixed to the upper end of the water lifting pipe 303. The mounting flange 318 is fixed to the pump mounting floor 352 by foundation bolts (not shown). The rotating shaft 105 extends vertically through the discharge bend pipe 305 and the water lifting pipe 303, and the lower end of the rotating shaft 105 is located inside the pump casing 301. The rotating shaft 105 is rotatably supported by an external bearing 324 and a sliding bearing 321.

[0135] The rotating shaft 105 protrudes upward from the discharge bend 305 and is connected to the motor rotating shaft 60a of the prime mover 60 via the MR fluid clutch 150. The external bearing 324 is located outside the discharge bend 305 and rotatably supports the portion of the rotating shaft 105 that protrudes from the discharge bend 305. A sliding bearing supporting the rotating shaft 105 may be further located inside the pumping pipe 303. The external bearing 324 is fixed to the upper part of the discharge bend 305 and supports the upper part of the rotating shaft 105. The sliding bearing 321 is located inside the discharge bowl 314 and supports the lower part of the rotating shaft 105. The sliding bearing 321 is immersed in the liquid during operation of the vertical shaft pump device 300.

[0136] An inner bowl 315 is located inside the discharge bowl 314, and the inner bowl 315 is connected to the discharge bowl 314 by a plurality of guide vanes 327. The plurality of guide vanes 327 are located above (on the discharge side of) the impeller 110. A liquid flow path is formed between the inner surface of the discharge bowl 314 and the outer surface of the inner bowl 315.

[0137] The torque of the prime mover 60 is transmitted to the rotating shaft 105 via the MR fluid clutch 150, causing the impeller 110 to rotate together with the rotating shaft 105. As the impeller 110 rotates, the liquid in the suction tank 350 is drawn in through the suction port 312a of the pump casing 301. The rotation of the impeller 110 causes the liquid to pass through the pump casing 301, the lifting pipe 303, and the discharge bend 305, and is then discharged from the discharge piping 308 to the discharge tank 360.

[0138] The MR fluid clutch 150 can reduce the rotation of the impeller 110 or stop the rotation of the impeller 110 while maintaining the rotation of the prime mover 60. In particular, a vertical shaft pump device 300 that handles liquids places a large load on the prime mover 60 when it starts up. The MR fluid clutch 150 can prevent overloading of the prime mover 60 by performing a soft start on the vertical shaft pump device 300. Furthermore, if a malfunction occurs in the rotation of the impeller 110, the current supply device 30 can momentarily stop the current flowing to the electromagnet 28, thereby disconnecting it from the prime mover 60 and preventing further damage to the pump device.

[0139] Furthermore, in flood control systems such as river drainage, if the discharge river reaches a dangerously high water level, the operation of the pump system for draining tributaries may be stopped to prevent the main river's levee from collapsing. Conventional standby pump systems require the prime mover to be stopped, but the vertical shaft pump system 300 incorporating the MR fluid clutch 150 allows the system to wait for the main river's water level to drop to a level where it can be drained without stopping the prime mover 60. When the water level reaches a level where it can be drained, the rotation of the impeller 110 is reduced by the MR fluid clutch 150, thereby suppressing rapid fluctuations in the river's water level and enabling safe drainage.

[0140] As described above with reference to Figures 1 to 13, any one of the embodiments of the MR fluid clutch system 100 can suppress the temperature rise of the MR fluid F in the MR fluid chamber 20 and prevent leakage and deterioration of the MR fluid F by circulating the medium L of the MR fluid F between the MR fluid chamber 20 and the medium tank 50. Furthermore, since the medium L of the MR fluid F is supplied to the MR fluid chamber 20 from the medium tank 50 through the medium circulation line 52, vaporization of the medium L of the MR fluid F in the MR fluid chamber 20 can be suppressed. As a result, stabilization of the torque transmission performance of the MR fluid F and prevention of leakage and deterioration of the MR fluid F can be achieved. Therefore, a pump facility equipped with a vertical shaft pump device 300 incorporating such an MR fluid clutch system 100 can perform stable pump operation.

[0141] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of Symbols]

[0142] 1 First axis structure 2 Second axis structure 3. First rotation axis 3a opening 4. Second rotation axis 4a opening 5, 5A, 5B, 5C, 5D, 5E First Rotating Plate 6, 6A, 6B, 6C, 6D Second Rotating Plate 8. First connecting member 8a Axial connection wall 8b Peripheral wall 8c Plate Cover Wall 8d axis cover wall 8E, 8F, 8G First connecting member 9. Second connecting member 12 Static Housing 13 Inlet 14 Outlet 15. First bearing 16. Second bearing 17 Intermediate bearing 20 MR fluid chamber (magneto-rheological fluid chamber) 25 Media room 28 Electromagnet 30 Current supply device 35 First sealing device 36. Second sealing device 37 Third sealing device 40, 40A, 40B filter device 42 Filter channel 43 Magnets 43a 1st pole 43b 2nd pole 44 Spacers 45 Filter casing 50 media tanks 52 Media circulation line 53 Media supply lines 54 Media return line 56 pumps 56a Pump rotating shaft 58 Cooling device 60 Engine 60a Motor rotating shaft 63 Torque transmission mechanism 65, 66 Pulley 67 belt 70 coils 71 Magnetic material 72 Fixing member 73 Electromagnet support member 75 Brush electrodes 80 1st shaft internal flow path 82 2nd shaft internal flow path 85 First Rotation Mechanism 87, 88 Pulley 89 belt 90 Second Rotation Mechanism 92, 93 Pulley 94 belt 96 First Seal Case 97 Second sealed case 99A, 99B Case sealing device 100 MR Fluid Clutch System (Magnetic Viscous Fluid Clutch System) 105 Rotation axis 110 Impeller 150 MR Fluid Clutch (Magnetic Viscous Fluid Clutch) 200 MR Fluid Brake System (Magnetic Viscous Fluid Brake System) 201 Fixed axis 203 Stationary Plate 250 MR fluid brake (magnetorheological fluid brake) 300 Vertical shaft pump device 301 Pump Casing 303 Water pumping pipe 305 Discharge bent pipe 308 Discharge piping 310 Bracket 312 Intake Bell Mouth 312a Inlet 314 Discharge bowl 315 Inner bowl 318 Mounting flange 321 Plain bearing 324 Outer bearing 327 Guide vanes 331 Discharge valve 332 Check valve 350 Suction Tank 352 Pump installation floor 355 Aperture 360 Discharge Tank F MR fluid (magnetoviscous fluid) L medium

Claims

1. The first axis of rotation and The second axis of rotation and A first rotating plate connected to the first rotating shaft and capable of rotating integrally with the first rotating shaft, A second rotating plate connected to the second rotating shaft and capable of rotating integrally with the second rotating shaft, An MR fluid chamber containing MR fluid that fills the gap between the first rotating plate and the second rotating plate, A stationary housing that houses the aforementioned MR fluid chamber inside, An inlet that communicates with the MR fluid chamber and allows the medium of the MR fluid to flow into the MR fluid clutch from outside the MR fluid clutch, An outlet that communicates with the MR fluid chamber and allows the medium in the MR fluid clutch to flow out of the MR fluid clutch, An MR fluid clutch comprising an electromagnet that generates a magnetic field applied to the aforementioned MR fluid.

2. The MR fluid clutch according to claim 1, further comprising a filter device that communicates with the MR fluid chamber and allows the passage of the medium without allowing magnetic particles in the MR fluid to pass through.

3. The MR fluid clutch according to claim 2, wherein the filter device is a magnetic seal device having a filter channel that allows the passage of the medium and a magnet arranged around the filter channel, and the magnetic field generated by the magnet prevents the magnetic particles from passing through the filter channel.

4. The MR fluid clutch according to claim 2, wherein the filter device has a filtration accuracy smaller than the particle size of the magnetic particles.

5. The MR fluid clutch according to claim 1, wherein the MR fluid chamber is formed by a first shaft structure having the first rotating shaft and the first rotating plate, a second shaft structure having the second rotating shaft and the second rotating plate, and a sealing device that seals the gap between the first shaft structure and the second shaft structure.

6. The MR fluid chamber, the inlet, and the outlet are further connected to a medium chamber filled with the medium, The media chamber is formed by the stationary housing, The inlet and outlet are provided in the stationary housing, The MR fluid clutch according to claim 2, wherein the filter device is disposed between the MR fluid chamber and the medium chamber.

7. The MR fluid clutch according to claim 6, wherein the filter device is attached to the wall surface of the first axial structure forming the MR fluid chamber.

8. A first internal shaft channel formed inside the first rotating shaft, The second internal shaft channel is further formed inside the second rotating shaft, The MR fluid clutch according to any one of claims 1 to 5, wherein the first internal shaft passage and the second internal shaft passage are in communication with the MR fluid chamber.

9. An MR fluid clutch according to any one of claims 1 to 7, A medium tank in which the medium of the MR fluid is stored, A media circulation line for circulating the media between the media tank and the MR fluid chamber, The aforementioned medium circulation line includes a pump, The inlet and outlet are connected to the medium circulation line in an MR fluid clutch system.

10. The MR fluid clutch system according to claim 9, further comprising a filter device disposed between the medium circulation line and the MR fluid chamber, which allows the medium to pass through without allowing magnetic particles in the MR fluid to pass through.

11. The MR fluid clutch system according to claim 9, further comprising a cooling device for cooling the medium flowing through the medium circulation line.

12. The MR fluid clutch system according to claim 9, further comprising a torque transmission mechanism for transmitting the torque of a prime mover connected to the first rotating shaft to the pump.

13. The MR fluid clutch according to claim 8, A medium tank in which the medium of the MR fluid is stored, A media circulation line for circulating the media between the media tank and the MR fluid chamber, The aforementioned medium circulation line includes a pump, The MR fluid clutch is further equipped with a filter device positioned between the medium circulation line and the MR fluid chamber, which allows the medium to pass through without allowing magnetic particles in the MR fluid to pass through. The aforementioned media circulation line is A medium supply line for supplying the medium from the medium tank to the MR fluid chamber, The system includes a medium return line for returning the medium from the MR fluid chamber to the medium tank. The filter device comprises a first filter device connected to the medium supply line and a second filter device connected to the medium return line. The inlet is connected to the medium supply line via the first filter device. The outlet is connected to the medium return line via the second filter device, in an MR fluid clutch system.

14. The MR fluid clutch system according to claim 13, further comprising a cooling device for cooling the medium flowing through the medium circulation line.

15. A pump device incorporating the MR fluid clutch system described in claim 9, A pumping system comprising a prime mover for driving the aforementioned pumping device.

16. A pump device incorporating the MR fluid clutch system described in claim 13, A pumping system comprising a prime mover for driving the aforementioned pumping device.

17. Fixed axis and The axis of rotation and A stationary plate connected to the aforementioned fixed shaft, A rotating plate connected to the aforementioned rotating shaft and capable of rotating integrally with the aforementioned rotating shaft, An MR fluid chamber containing MR fluid that fills the gap between the stationary plate and the rotating plate, A stationary housing that houses the aforementioned MR fluid chamber inside, An inlet that communicates with the aforementioned MR fluid chamber and allows the medium of the MR fluid to flow in from outside the MR fluid brake, An outlet that communicates with the MR fluid chamber and allows the medium to flow out of the MR fluid brake, An MR fluid brake, comprising an electromagnet that generates a magnetic field applied to the aforementioned MR fluid.

18. The MR fluid brake according to claim 17, further comprising a filter device that communicates with the MR fluid chamber and allows the passage of the medium without allowing magnetic particles in the MR fluid to pass through.

19. The MR fluid brake according to claim 17, A medium tank in which the medium of the MR fluid is stored, A media circulation line for circulating the media between the media tank and the MR fluid chamber, An MR fluid brake system comprising a pump located in the aforementioned fluid circulation line.

20. The MR fluid brake system according to claim 19, further comprising a filter device disposed between the medium circulation line and the MR fluid chamber, which allows the medium to pass through without allowing magnetic particles in the MR fluid to pass through.

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