Torque generation device

Abstract

To fill an entire gap between two yokes with magnetic viscous fluid in a short period of time.SOLUTION: A torque generation device includes: a rotational shaft; a magnetic disk that is provided at a tip of the rotational shaft and that can rotate integrally with the rotational shaft; a first yoke facing a first face on an opposite side of the rotational shaft side of the magnetic disk; a coil and a second yoke provided on a second face side of the rotational shaft side of the magnetic disk; and a magnetic viscous fluid provided in a gap between the first yoke and the second yoke. The magnetic disk includes one or more first through holes, and the first yoke includes one or more second through holes. The first through holes of the magnetic disk are provided on a circumference about the rotational shaft, and the second through holes of the first yoke are provided on a circumference about the rotational shaft.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a torque generating device. [Background technology]

[0002] Conventionally, a torque generating device has been known in which a magnetic disk is placed between two yokes, filled with a magnetorheological fluid, and the viscosity of the magnetorheological fluid is increased by the magnetic field generated by an excitation coil, thereby changing the rotational resistance of the rotating shaft.

[0003] Furthermore, in the past, in such torque generating devices, a technology has been devised in which a magnetorheological fluid is filled between two yokes through a through hole formed in the center of the yoke provided on the tip side of the rotating shaft (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 220771 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology of Patent Document 1, it was difficult for the magnetorheological fluid to flow into the gaps on both sides of the magnetic disk (especially the side opposite the through-hole side), making it difficult to fill the entire gap between the two yokes with the magnetorheological fluid in a short period of time. [Means for solving the problem]

[0006] A torque generating device according to one embodiment comprises a rotating shaft, a magnetic disk provided at the tip of the rotating shaft and rotatable integrally with the rotating shaft, a first yoke provided opposite a first surface of the magnetic disk opposite the rotating shaft side, a coil and a second yoke provided on a second surface of the magnetic disk on the rotating shaft side, and a magnetorheological fluid filled between the first yoke and the second yoke, wherein the magnetic disk has one or more first through holes, the first yoke has one or more second through holes, the first through holes of the magnetic disk are arranged on a circumference centered on the rotating shaft, and the second through holes of the first yoke are arranged on a circumference centered on the rotating shaft. [Effects of the Invention]

[0007] According to the torque generating device of one embodiment, the magnetorheological fluid can be filled into the entire gap between the two yokes in a short time. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an external perspective view of a torque generating device according to an embodiment, as viewed from above; [Figure 2] FIG. 1 is a perspective view of a torque generating device according to an embodiment, viewed from below; [Figure 3] 1 is a cross-sectional perspective view of a torque generating device according to an embodiment; [Figure 4] FIG. 1 is an exploded perspective view of a torque generating device according to an embodiment, viewed from above; [Figure 5] 1 is an exploded perspective view of a torque generating device according to an embodiment, viewed from below; FIG. [Figure 6] 1 is a bottom view of a torque generating device according to an embodiment; [Figure 7] 1 is a cross-sectional view illustrating a method for filling a magnetorheological fluid in a torque generating device according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment will be described below with reference to the drawings. For convenience, in the following description, the Z-axis direction in the drawings is the up-down direction, the X-axis direction in the drawings is the left-right direction, and the Y-axis direction in the drawings is the front-rear direction. However, the positive Z-axis direction is the up direction, the positive X-axis direction is the right direction, and the positive Y-axis direction is the front.

[0010] (Overview of Torque Generator 100) Fig. 1 is a perspective view of the appearance of a torque generator 100 according to one embodiment, as viewed from above. Fig. 2 is a perspective view of the appearance of a torque generator 100 according to one embodiment, as viewed from below.

[0011] As shown in Figures 1 and 2, the torque generating device 100 comprises a container-shaped first yoke 110 having an accommodation space 110A (see Figures 3 and 4), a flat second yoke 120 attached to the top of the first yoke 110, and a round bar-shaped rotating shaft 130 extending upward (in the positive direction of the Z axis) from the accommodation space of the first yoke 110 through a through hole 121 provided in the center of the second yoke 120.

[0012] The rotating shaft 130 is rotatable around its own axis. Inside the first yoke 110, a magnetic disk 140 that rotates integrally with the rotating shaft 130 and a coil 150 are provided, and further, the first yoke 110 is filled with a magnetorheological fluid 160 (see FIGS. 3 to 5).

[0013] As shown in FIG. 1, two external connection terminals 153 are provided on the upper surface of second yoke 120 so as to protrude upward (in the positive direction of the Z axis).

[0014] The torque generating device 100 generates magnetism inside the first yoke 110 by supplying current to the coil 150 via two external connection terminals 153, and the magnetism increases the viscosity of the magnetorheological fluid 160, thereby increasing the rotational resistance of the magnetic disk 140 and braking the rotation of the magnetic disk 140 and the rotating shaft 130.

[0015] (Configuration of torque generating device 100) Fig. 3 is a cross-sectional perspective view of the torque generator 100 according to one embodiment. Fig. 4 is an exploded perspective view of the torque generator 100 according to one embodiment, as viewed from above. Fig. 5 is an exploded perspective view of the torque generator 100 according to one embodiment, as viewed from below.

[0016] As shown in FIGS. 3 to 5, the torque generator 100 includes a first yoke 110, a second yoke 120, a third yoke 151, a rotating shaft 130, a magnetic disk 140, a coil 150, a magnetorheological fluid 160, and a sealing member 170.

[0017] The first yoke 110 is a container-shaped member made of a magnetic material. The first yoke 110 has a storage space 110A that is open at the top. When viewed from above (positive Z-axis direction), the storage space 110A has a circular shape with a diameter larger than that of the magnetic disk 140 and a certain depth in the vertical direction (Z-axis direction). Two second through-holes 111 that penetrate the bottom surface 110B of the first yoke 110 in the vertical direction (Z-axis direction) are formed in the bottom surface 110B of the first yoke 110. As shown in FIG. 3, the magnetic disk 140, the third yoke 151, and the coil 150 are disposed in the storage space 110A. This creates gaps around the magnetic disk 140 (on the outer diameter side, upper side (positive Z-axis side), and lower side (negative Z-axis side)). A magnetorheological fluid 160 is filled in these gaps.

[0018] The second yoke 120 is a flat plate-shaped member made of a magnetic material. The second yoke 120 is attached to the top of the first yoke 110, thereby closing the top opening of the accommodation space 110A of the first yoke 110. The second yoke 120 is fixed to the first yoke 110 by a plurality of screws 122 that pass through the second yoke 120. A through hole 121 that passes through the second yoke 120 in the up-down direction (Z-axis direction) is formed in the center of the second yoke 120. A bearing 123 is provided in the through hole 121 of the second yoke 120 to smooth the rotation of the rotation shaft 130.

[0019] The rotating shaft 130 is a metallic round bar-shaped member that extends in the vertical direction (Z-axis direction). The rotating shaft 130 passes through a bearing 123 provided in a through-hole 121 of the second yoke 120 and is provided rotatably around its own axis.

[0020] The magnetic disk 140 is a disk-shaped member made of a magnetic material. The magnetic disk 140 is arranged in a horizontal position in the accommodation space 110A of the first yoke 110. The magnetic disk 140 is fixed at its center to the lower end 130A of the rotation shaft 130 located in the accommodation space 110A by a bolt 131. This allows the magnetic disk 140 to rotate integrally with the rotation shaft 130 around the axis of the rotation shaft 130. A first surface 140A on the lower side (negative side of the Z axis) of the magnetic disk 140 faces a bottom surface 110B of the first yoke 110 across a gap. A second surface 140B on the upper side (positive side of the Z axis) of the magnetic disk 140 faces a lower surface of the third yoke 151 across a gap. Four first through-holes 141 are formed in the magnetic disk 140, penetrating the magnetic disk 140 in the up-down direction (Z-axis direction).

[0021] The coil 150 is disposed in the housing space 110A of the first yoke 110, facing the second surface 140B on the upper side (positive side of the Z axis) of the magnetic disk 140. The coil 150 is configured by multiple windings of a conductive wire 152 around the outer circumferential surface of a cylindrical bobbin 154. External connection terminals 153 are provided at both ends of the conductive wire 152. A through-hole 150A is formed in the center of the coil 150, penetrating the coil 150 in the vertical direction. The rotation shaft 130 is inserted through the through-hole 150A. When a current is supplied to the conductive wire 152 via the two external connection terminals 153, the coil 150 generates a magnetic field around the coil 150. The two external connection terminals 153 penetrate the second yoke 120 and protrude upward (positive direction of the Z axis) from the second yoke 120. The third yoke 151 is fixed to the lower surface of the second yoke 120 by a plurality of screws 124 .

[0022] The magnetorheological fluid 160 is filled in the accommodation space 110A of the first yoke 110 (i.e., between the first yoke 110 and the second yoke 120). Specifically, the magnetorheological fluid 160 is filled in the gap around the magnetic disk 140 sandwiched between the first yoke 110 and the third yoke 151 in the accommodation space 110A of the first yoke 110. The magnetorheological fluid 160 is a fluid containing ferromagnetic particles (e.g., ferrite particles), and its viscosity increases due to the magnetism generated by the coil 150. Note that in this embodiment, the magnetorheological fluid 160 may have any viscosity. For example, the magnetorheological fluid 160 may have a relatively low viscosity with a relatively small content of ferromagnetic particles, or may have a relatively high viscosity with a relatively large content of ferromagnetic particles.

[0023] The sealing member 170 is a flat plate-shaped member made of an elastic material. After the magnetorheological fluid 160 is filled into the accommodation space 110A of the first yoke 110, the sealing member 170 is attached to the lower surface of the bottom surface portion 110B of the first yoke 110 by an adhesive means (double-sided tape, adhesive, sealant, etc.). The sealing member 170 covers the two second through holes 111 formed in the bottom surface portion 110B of the first yoke 110, thereby preventing the magnetorheological fluid 160 from leaking from the two second through holes 111.

[0024] The torque generating device 100 configured as described above generates magnetism around the coil 150 by supplying current to the conductor 152 of the coil 150 via the external connection terminal 153, and this magnetism increases the viscosity of the magnetorheological fluid 160, thereby increasing the rotational resistance of the magnetic disk 140 and braking the rotation of the magnetic disk 140 and the rotating shaft 130.

[0025] (Configuration for filling magnetorheological fluid 160) FIG. 6 is a bottom view of the torque generating device 100 according to one embodiment.

[0026] As shown in Fig. 6, two second through holes 111 are formed in the bottom surface portion 110B of the first yoke 110, penetrating the bottom surface portion 110B in the up-down direction (Z-axis direction). As shown in Fig. 6, the two second through holes 111 are provided on the same circumference as a circumference c0 having a predetermined radius r, and have curved shapes that follow the circumference c0. The two second through holes 111 also have the same shape. The two second through holes 111 are also provided point-symmetrically, i.e., are provided at equal intervals (180° apart) on the circumference c0.

[0027] 6, the magnetic disk 140 is formed with four first through holes 141 that penetrate the magnetic disk 140 in the up-down direction (Z-axis direction). As shown in FIG. 6, the four first through holes 141, like the two second through holes 111, are provided on the same circumference as a circumference c0 having a predetermined radius r, and have curved shapes that follow the circumference c0. The four first through holes 141 have the same shape as each other. The four first through holes 141 are provided point-symmetrically, i.e., are provided at equal intervals (90° intervals) on the circumference c0.

[0028] In this way, in one embodiment of the torque generating device 100, the first through hole 141 of the magnetic disk 140 and the second through hole 111 of the first yoke 110 are each arranged on a circumference centered on the rotation axis 130.

[0029] As a result, the torque generating device 100 of one embodiment can make it easier for the magnetorheological fluid 160 injected from the second through-hole 111 to flow to the back side (positive Z-axis side) of the magnetic disk 140 via the first through-hole 141, and therefore the magnetorheological fluid 160 can fill the entire gap on both the top and bottom sides of the magnetic disk 140 (i.e., the entire gap between the two yokes 110, 151) in a short period of time.

[0030] Furthermore, in the torque generator 100 according to one embodiment, the first through-hole 141 of the magnetic disk 140 and the second through-hole 111 of the first yoke 110 are provided on the same circumference.

[0031] As a result, when the torque generating device 100 of one embodiment is viewed in a plan view from below (negative Z-axis direction) as shown in Figure 6, the first through hole 141 and the second through hole 111 overlap, making it easier for the magnetorheological fluid 160 injected from the second through hole 111 to flow into the back side (positive Z-axis side) of the magnetic disk 140 via the first through hole 141.Therefore, the magnetorheological fluid 160 can be filled in the entire gap on both the upper and lower sides of the magnetic disk 140 (i.e., the entire gap between the two yokes 110, 120) in a short period of time.

[0032] It should be noted that the first through hole 141 and the second through hole 111 do not need to be perfectly aligned. If the first through hole 141 and the second through hole 111 partially overlap, the magnetorheological fluid 160 can be more easily flowed through the first through hole 141 to the back side (positive Z-axis side) of the magnetic disk 140. In other words, it is sufficient that the first through hole 141 and the second through hole 111 partially overlap the circumference c0, and the centers of the first through hole 141 and the second through hole 111 do not need to be on the circumference c0. However, it is preferable that the maximum width and length of the overlap between the first through hole 141 and the second through hole 111 be greater than 0.5 mm. When the magnetorheological fluid is injected into the first through-hole 141 and the second through-hole 111 with an overlapping dimension of more than 0.5 mm in length and width, the magnetorheological fluid 160 can easily flow into the back side (positive Z-axis side) of the magnetic disk 140 as well.

[0033] Furthermore, in one embodiment of the torque generating device 100, as shown in FIG. 6, a plurality of first through holes 141 are provided on the same circumference in the magnetic disk 140, and the distance between two adjacent first through holes 141 in the circumferential direction in the magnetic disk 140 (i.e., the circumferential length of the portion where no first through holes 141 are provided) is shorter than the circumferential length of the second through hole 111 in the first yoke 110.

[0034] As a result, the torque generating device 100 of one embodiment can ensure that the first through hole 141 and the second through hole 111 always overlap, and therefore, regardless of the rotation angle of the magnetic disk 140, the magnetic rheological fluid 160 injected from the second through hole 111 can easily flow into the gap on the back side (positive side of the Z axis) of the magnetic disk 140 via the first through hole 141.

[0035] In addition, in one embodiment of the torque generating device 100, as shown in FIG. 6, the first through hole 141 of the magnetic disk 140 and the second through hole 111 of the first yoke 110 are both located inside a circumference c1 having a radius that is 1 / 2 of the radius of the magnetic disk 140.

[0036] As a result, in the torque generating device 100 according to one embodiment, by rotating the magnetic disk 140, the magnetorheological fluid 160 injected from the second through-hole 111 can be filled from the inner diameter side to the outer diameter side of the magnetic disk 140 by centrifugal force, thereby making it difficult for voids to occur. Furthermore, if the first through-hole 141 is provided on the outer diameter side of the circumference c1, the effect on the shear stress of the magnetic disk 140 becomes greater. If the first through-hole 141 is provided inside the circumference c1, a decrease in shear stress can be suppressed even in a small device.

[0037] Furthermore, in the torque generating device 100 according to one embodiment, the first yoke 110 has two second through holes 111 provided point-symmetrically, as shown in FIG.

[0038] As a result, in one embodiment of the torque generating device 100, by injecting the magnetorheological fluid 160 from one of the second through holes 111, air can be released from the other second through hole 111, and therefore the magnetorheological fluid 160 can be filled in a short time.

[0039] Furthermore, this allows the torque generating device 100 of one embodiment to increase the circumferential length of the second through hole 111, thereby increasing the amount of magnetorheological fluid 160 injected from the second through hole 111.

[0040] In addition, in one embodiment of the torque generating device 100, as shown in FIG. 6, the circumferential length of the second through hole 111 of the first yoke 110 is longer than the circumferential length of the first through hole 141 of the magnetic disk 140.

[0041] When the magnetic disk 140 is rotated, the magnetorheological fluid 160 can be injected from the outside by centrifugal force, making it difficult for air bubbles to remain in the magnetorheological fluid 160. In particular, if the magnetorheological fluid 160 can be injected while the magnetic disk 140 is rotating, the magnetorheological fluid 160 can be injected in a short time. For example, if the magnetorheological fluid 160 is injected from the counterclockwise end of the second through-hole 111 on the right side of FIG. 6 while the magnetic disk 140 is rotated clockwise, the magnetorheological fluid 160 gradually flows from the second through-hole 111 into the gap around the magnetic disk 140 (between the first yoke 110 and the third yoke 151). The first yoke 110 has a thickness of several millimeters to several centimeters, and can temporarily store the magnetorheological fluid 160 by the volume of the second through-hole 111. This makes it difficult for the magnetorheological fluid 160 to overflow from the second through-hole 111.

[0042] Furthermore, in one embodiment of the torque generating device 100, as shown in FIG. 6, the radial width of the first through hole 141 of the magnetic disk 140 is greater than the radial width of the second through hole 111 of the first yoke 110.

[0043] As a result, the torque generating device 100 of one embodiment can make it easier for the magnetorheological fluid 160 injected from the second through hole 111 to pass through the first through hole 141, and therefore can make it easier for the magnetorheological fluid 160 injected from the second through hole 111 to flow into the gap on the back side (positive side of the Z axis) of the magnetic disk 140 via the first through hole 141.

[0044] (Method of filling magnetorheological fluid 160) FIG. 7 is a cross-sectional view illustrating a method of filling the torque generating device 100 according to one embodiment with the magnetorheological fluid 160. In FIG.

[0045] As shown in FIG. 7, the torque generating device 100 according to one embodiment can be turned upside down (i.e., the direction of gravity is above the torque generating device 100 (positive Z-axis direction)), and the magnetorheological fluid 160 can be filled into the storage space 110A of the first yoke 110 (i.e., the gap around the magnetic disk 140) through one of the two second through holes 111 formed in the bottom surface portion 110B of the first yoke 110 by using a nozzle 10 provided in a filling device.

[0046] Here, as shown in FIG. 7, in the torque generating device 100 according to one embodiment, the first through hole 141 of the magnetic disk 140 is provided at a position overlapping with the second through hole 111 of the first yoke 110. This allows the magnetorheological fluid 160 injected from the second through hole 111 to easily flow into the gap on the back side (positive side of the Z axis) of the magnetic disk 140 via the first through hole 141. Therefore, the magnetorheological fluid 160 can be filled in the entire gap on both the upper and lower sides of the magnetic disk 140 (i.e., the entire gap between the two yokes 110, 120) in a short time.

[0047] At this time, the magnetic disk 140 may be rotated or vibration may be applied to the torque generator 100 to promote filling of the magnetorheological fluid 160 into the entire gap around the magnetic disk 140 .

[0048] In addition, in the torque generating device 100 according to one embodiment, after the magnetorheological fluid 160 is filled, a sealing member 170 made of an elastic material is attached to the lower surface (the surface on the negative side of the X-axis) of the bottom surface portion 110B of the first yoke 110 to cover the two second through holes 111 (see FIG. 2), thereby preventing leakage of the magnetorheological fluid 160 from the two second through holes 111.

[0049] As a result, the torque generating device 100 according to one embodiment does not need to provide a sealing member such as an O-ring inside the second through-hole 111, and therefore the effective size of the second through-hole 111 for injecting the magnetorheological fluid 160 can be increased. Furthermore, by using an elastic material for the sealing member 170, stress due to thermal expansion of the magnetorheological fluid 160 can be released by the sealing member 170 elastically deforming (the central portion expanding in the negative Z-axis direction). Therefore, it is preferable that only the outer peripheral portion of the sealing member 170 be attached to the lower surface of the bottom portion 110B of the first yoke 110.

[0050] 6 and 7, no through-hole is formed in the center of the bottom surface portion 110B of the first yoke 110. Therefore, in the torque generator 100 according to one embodiment, the lower end portion 130A of the rotating shaft 130 can be brought into contact with the center of the surface on the positive side of the Z axis of the bottom surface portion 110B. This allows the rotating shaft 130 and the magnetic disk 140 to be positioned in the up-down direction (Z axis direction) with high precision, and also prevents wobbling of the rotating shaft 130 and the magnetic disk 140 in the up-down direction (Z axis direction). Therefore, the torque generator 100 according to one embodiment can maintain a constant gap between the top and bottom of the magnetic disk 140.

[0051] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0052] For example, the number of second through holes 111 in first yoke 110 is not limited to two, but may be one or three or more. Also, for example, the number of first through holes 141 in magnetic disk 140 is not limited to four, but may be three or less or five or more.

[0053] Also, for example, in the above embodiment, the first through hole 141 of the magnetic disk 140 and the second through hole 111 of the first yoke 110 are provided on the inner diameter side of the circumference c1, but this is not limited thereto, and they may be provided, for example, on the circumference c1 or on the outer diameter side of the circumference c1.

[0054] Furthermore, the torque generating device 100 may include a structure for rotating the rotary shaft 130 by, for example, an electric motor or the like. [Explanation of symbols]

[0055] 100 Torque Generator 110 First York 110A Storage Space 110B Bottom part 111 Second through hole 120 Second York 121 Through hole 122 screws 123 Bearing 124 screws 130 Rotational Axis 131 volts 140 Magnetic Disk 140A First Side 140B Second Side 141 First through hole 150 coils 150A through hole 151 The Third York 152 Conductor 153 External connection terminal 154 Bobbin 160 Magnetorheological fluid 170 Sealing material r radius c0,c1 circumference

Claims

1. A rotation axis; a magnetic disk provided at the tip of the rotary shaft and rotatable integrally with the rotary shaft; a first yoke provided opposite to a first surface of the magnetic disk opposite to the rotation shaft; a coil and a second yoke provided on a second surface of the magnetic disk that faces the rotation shaft; a magnetorheological fluid filled between the first yoke and the second yoke; Equipped with the magnetic disk has one or more first through holes; the first yoke has one or more second through holes; the first through-hole of the magnetic disk is provided on a circumference centered on the rotation axis, The second through-hole of the first yoke is provided on a circumference centered on the rotation axis. A torque generating device characterized by:

2. The first through hole and the second through hole are provided on the same circumference.

2. The torque generating device according to claim 1.

3. In the magnetic disk, a plurality of the first through holes are provided on the same circumference, In the magnetic disk, the distance between two adjacent first through holes in the circumferential direction is shorter than the length in the circumferential direction of the second through hole of the first yoke.

3. The torque generating device according to claim 2.

4. The first through-hole of the magnetic disk and the second through-hole of the first yoke are both provided inside a circumference having a radius that is half that of the magnetic disk.

4. The torque generating device according to claim 3.

5. The first yoke has two second through holes provided point-symmetrically.

5. The torque generating device according to claim 4.

6. The length of the second through hole in the first yoke in the circumferential direction is longer than the length of the first through hole in the magnetic disk in the circumferential direction.

6. The torque generating device according to claim 5.

7. The radial width of the first through hole of the magnetic disk is greater than the radial width of the second through hole of the first yoke.

7. The torque generating device according to claim 6.

8. a sealing member made of an elastic material and attached to the first yoke so as to cover the second through-hole of the first yoke; 8. A torque generating device according to claim 1.

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