Rotary braking device

Abstract

Provided is a rotary braking device capable of improving braking force by increasing shearing resistance of viscous fluid. A rotary brake device 10 has a first rotary member 20 and a second rotary member 50. The first rotary member 20 has a base part 21, an inner cylinder part 23, an outer cylinder part 25, an intermediate cylinder part 27, annular spaces 29, 30, and an opening part 31. The second rotary member 50 has a closing part 51 and a plurality of cylinder parts 53, 55. A slit 40 extending in an axial direction is formed in the intermediate cylinder part 27. At a position in the intermediate cylinder part 27 where the intermediate cylinder part 27 is aligned with the slit 40 in the circumferential direction, there is formed a slit-shortening part 45 that reduces the axial length of the slit 40 from the base part 21 toward the opening part 31.

Description

Rotational braking device

[0001] The present invention relates to a rotary braking device used, for example, for braking the opening and closing of a console box of an automobile.

[0002] For example, a rotational braking device is sometimes used in a console box or glove box of an automobile to prevent the lid from suddenly closing or opening, and to allow the lid to close or open gradually.

[0003] For example, Patent Document 1 listed below describes a rotary damper that comprises a driven rotating member having an integral gear, a fixed support member that rotatably holds the driven rotating member, and a viscous fluid interposed between the two members, wherein the fixed support member is circular and has a dish-shaped portion inside which the viscous fluid is placed, and the driven rotating member has a circular inverted dish-shaped portion that is rotatably held on the inner periphery of the cylindrical wall of the dish-shaped portion, and the underside of the upper wall of the inverted dish-shaped portion is provided with wing pieces that protrude into the viscous fluid inside the dish-shaped member.

[0004] The dish-shaped portion of the fixed support member has a bottom wall, and a plurality of arc-shaped walls are provided at equal intervals in the circumferential direction on a circle of a predetermined diameter about the center of the bottom wall (see Figure 5 of Patent Document 1). A plurality of wing pieces of the inverted dish-shaped portion of the driven rotating member are rotatably arranged inside these arc-shaped walls.

[0005] Japanese Utility Model Application Laid-Open Publication No. 5-14689

[0006] In the rotary damper of Patent Document 1, there is a gap between the circumferentially adjacent arc-shaped walls provided on the fixed support member, and a viscous fluid can flow through this gap. Therefore, when the driven rotating member rotates relative to the fixed support member and the blade piece attempts to rotate by shearing the viscous fluid between the arc-shaped walls, the viscous fluid escapes from the gap, making it difficult to generate shear resistance and obtain a high braking force.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotary braking device that can increase the shear resistance of a viscous fluid and improve braking force.

[0008] In order to achieve the above object, the present invention provides a rotary braking device that is disposed between a pair of members that rotate relative to each other and that applies a braking force during the relative rotation, the rotary braking device having a first rotary member and a second rotary member that is assembled to the first rotary member so as to be rotatable relative to the first rotary member, the first rotary member having a base portion, an inner cylindrical portion that extends from the inside of the base portion, an outer cylindrical portion that extends from the outside of the base portion concentrically with the inner cylindrical portion, at least one intermediate cylindrical portion that extends from between the inner cylindrical portion and the outer cylindrical portion of the base portion concentrically with the inner cylindrical portion and the outer cylindrical portion, and a viscous fluid that is concentrically defined between each of the cylindrical portions that are adjacent in the radial direction. The second rotating member has a plurality of annular spaces filled with fluid and an opening arranged opposite the base, and the second rotating member has a closing portion that closes the opening and a plurality of tubular portions that extend concentrically from the closing portion and are inserted into the plurality of annular spaces, and the intermediate tubular portion has a slit that extends axially from the opening toward the base and allows the viscous fluid to flow through, and a slit shortening portion is formed in the intermediate tubular portion at a position that is circumferentially aligned with the slit, from the base toward the opening, that shortens the axial length of the slit.

[0009] In the present invention, a slit shortening portion that shortens the axial length of the slit is formed in the intermediate tubular portion of the first rotating member, and the slit shortening portion is positioned opposite the tubular portion of the second rotating member.Therefore, the area of ​​the intermediate tubular portion that axially overlaps with the tubular portion of the second rotating member at a position that is circumferentially aligned with the slit can be increased, thereby increasing the shear resistance of the viscous fluid and improving the braking force.

[0010] 1 is an exploded perspective view showing one embodiment of a rotary braking device according to the present invention. FIG. 1 is a perspective view of the rotary braking device. FIG. 2 is a plan view of a first rotating member constituting the rotary braking device. FIG. 3 is a cross-sectional view taken along the arrows A-A in FIG. 3. FIG. 4 is an explanatory view of a first process of manufacturing the rotary braking device. FIG. 5 is an explanatory view of a second process of the rotary braking device. FIG. 6 is an explanatory view of a third process of the rotary braking device. FIG. 7 is an explanatory view of a fourth process of the rotary braking device. FIG. 8 is a cross-sectional view taken along the arrows E-E in FIG. 2, showing an initial state in which a braking force is generated in the rotary braking device. FIG. 11 is a cross-sectional view taken along the arrows E-E in FIG. 2, showing a state in which the other member has rotated in a predetermined direction relative to one member after the generation of a braking force (a state rotated from FIG. 12). FIG. 12 is a cross-sectional view taken along the arrows E-E in FIG. 2, showing a state in which the braking force is not applied in the rotary braking device from the state in FIG. 13. 14 is a cross-sectional view taken along the line E-E of the arrows in FIG. 2 in a state in which the other member has rotated relative to the one member in the direction opposite to the predetermined direction after the other member has entered a state in which braking is not applied (a state rotated from FIG. 14). A perspective view and an exploded perspective view are shown of a pair of members to which the rotational braking device can be applied, showing the assembled state. A cross-sectional view showing another embodiment of the rotational braking device according to the present invention.

[0011] (One embodiment of a rotational braking device) Hereinafter, one embodiment of a rotational braking device according to the present invention will be described with reference to the drawings.

[0012] As shown in Figure 16, this rotational braking device 10 is attached between a pair of members 1 and 6 that rotate relative to each other, and applies a braking force during the relative rotation. In particular, in this embodiment, a braking force is applied when one member, a first member 1, rotates in a predetermined direction relative to the other member, a second member 6.

[0013] This rotary braking device 10 can be used, for example, for braking a lid that is openably and closably attached to the opening of a console box of an automobile, as shown in Fig. 16. Note that the rotary braking device 10 is not particularly limited and may also be used for braking a glove box or lid that is openably and closably attached to the opening of a storage section provided in the instrument panel of an automobile, or for braking an assist grip that is openably and closably installed at a predetermined location inside the automobile.

[0014] In the following embodiments, one of the members is a fixed body such as a console box, which will be described as a first member 1. Furthermore, the other member is an opening / closing body such as a lid that is attached to an opening of the fixed body in an openable / closable manner, which will be described as a second member 6.

[0015] As shown in Figure 16, one of the members, the first member 1, is composed of a pair of side walls 2, 2 extending like a long plate and arranged parallel to each other, and connecting walls 3, 3 connecting both ends of the pair of side walls 2, 2 in the extension direction, and is in the shape of a long rectangular box with an opening 4 at the top.

[0016] A pair of notches 3a, 3a are formed on both sides in the width direction above one of the connecting walls 3. Furthermore, a braking device placement recess 3b is formed above one of the connecting walls 3 and between the pair of notches 3a, 3a.

[0017] Furthermore, a plurality of shaft insertion holes 3c are formed coaxially in the pair of cutouts 3a, 3a and the brake device mounting recess 3b. Furthermore, a protruding connected portion 5 protrudes from one inner surface of the brake device mounting recess 3b. This connected portion 5 is clamped between a pair of connecting protrusions 56, 56 of the second rotating member 50, which will be described later (see FIG. 16).

[0018] On the other hand, the second member 6, which is the other member, is formed in a generally long plate shape that fits into the opening 4 of the first member 1, and a pair of protrusions 7, 7 protrude from the base end in the longitudinal direction. A shaft insertion hole 7a is formed in each of the protrusions 7, 7. The pair of protrusions 7, 7 are inserted into the pair of cutouts 3a, 3a of the first member 1, respectively.

[0019] Then, by inserting a support shaft 9 into the shaft insertion hole 3c on the first member 1 side and the shaft insertion hole 7a on the second member 6 side, the second member 6 can be rotatably attached to the first member 1 via the support shaft 9.

[0020] A pair of connected portions 8, 8 protrude from the base end portion in the longitudinal direction of the second member 6, between the pair of protruding pieces 7, 7. A connecting protrusion 83 of an oscillating rotation member 80, which will be described later, is adapted to be inserted between the pair of connected portions 8, 8 (see FIG. 16).

[0021] 1 and 2, the rotary braking device 10 of this embodiment has a first rotating member 20 and a second rotating member 50 that is fixed to the first member 20 and assembled to be rotatable relative to the first rotating member 20, and is configured to apply a braking force when the first rotating member 20 and the second rotating member 50 rotate relative to each other. The first rotating member 20 and the second rotating member 50 are referred to as braking members 11.

[0022] First, the first rotating member 20 constituting the braking member 11 will be described with reference to FIGS. 1, 3, 4, etc.

[0023] The first rotating member 20 has a base 21 having a substantially annular plate shape, an inner cylindrical portion 23 extending a predetermined length from the inside (here, the inner peripheral edge) of the base 21, an outer cylindrical portion 25 extending a predetermined length from the outside (here, the outer peripheral edge) of the base 21 concentrically with the inner cylindrical portion 23, and an intermediate cylindrical portion 27 extending from between the inner cylindrical portion 23 and the outer cylindrical portion 25 of the base 21 concentrically with the inner cylindrical portion 23 and the outer cylindrical portion 25. In other words, the first rotating member 20 has a multiple cylindrical structure in which the cylindrical portions 23, 25, 27 are arranged concentrically and coaxially. The base does not have to be annular plate-shaped, and may be plate-shaped without holes.

[0024] In the following description, the extending direction of each of the cylindrical portions 23, 25, 27 will be described as the axial direction of the braking member 11. The extending direction of each of the cylindrical portions 53, 55 of the second rotating member 50 constituting the braking member 11 has the same meaning.

[0025] The first rotating member 20 has a first annular space 29 defined by the base portion 21, the intermediate cylindrical portion 27, and the inner cylindrical portion 23 disposed radially inward of the intermediate cylindrical portion 27, and also has a second annular space 30 defined by the base portion 21, the intermediate cylindrical portion 27, and the outer cylindrical portion 25 disposed radially outward of the intermediate cylindrical portion 27. The two annular spaces 29, 30 are arranged concentrically, and each annular space 29, 30 is filled with a viscous fluid N (see FIG. 5).

[0026] As shown in FIG. 4 , the inner cylindrical portion 23 and the intermediate cylindrical portion 27 have the same extending length, while the outer cylindrical portion 25 extends longer than the inner cylindrical portion 23 and the intermediate cylindrical portion 27 .

[0027] Furthermore, a tip end 23a in the extending direction of the inner cylindrical portion 23 has a stepped portion 23b that reduces the diameter of the tip end 23a compared to the remaining portion. A first seal ring S1 is fitted to this reduced-diameter tip end 23a, and the outer periphery of this first seal ring S1 is disposed in contact with the inner periphery of the inner cylindrical portion 53 of the second rotating member 50 to seal the viscous fluid filled in the braking member 11 (see FIG. 9).

[0028] Furthermore, the tip portion 25a in the extension direction of the outer tube portion 25 has a larger diameter than the portion other than the tip portion 25a via a stepped portion 25b, and the inner portion of this tip portion 25a forms an opening 31 arranged opposite the base portion 21.

[0029] Furthermore, a plurality of locking projections 33 (four locking projections 33 are provided in this example) are provided at equal intervals in the circumferential direction from the outer periphery of the most distal end portion of the tip end portion 25a of the outer tubular portion 25. As shown in Fig. 2, each locking projection 33 is locked to a locking step 71a on a peripheral wall portion 71 of a second case 70 constituting the third rotating member 15, thereby holding the second case 70 against separation from the first case 60.

[0030] Furthermore, a first engagement portion 35 is provided on the outer periphery of the outer tubular portion 25 closer to the base end than the tip end 25a. This first engagement portion 35 is made up of a plurality of first engagement teeth 36 provided around the entire outer periphery of the outer tubular portion 25 at the above-mentioned location.

[0031] 1 and 4, a plurality of retaining portions 38, each of which forms a circumferentially extending protrusion, are formed at equal intervals in the circumferential direction on the inner periphery of the tip end portion 25a of the outer tubular portion 25. Here, the four retaining portions 38 are provided so as to be positioned between the retaining protrusions 33, 33 that are arranged adjacent to each other in the circumferential direction, out of the four retaining protrusions 33 described above.

[0032] These multiple anti-slip portions 38 engage with the annular protrusion 55c (see Figure 1) of the second rotating member 50, thereby preventing the second rotating member 50 from slipping out in the axial direction relative to the first rotating member 20, and allowing the two rotating members 20, 50 to be assembled so as to allow relative rotation.

[0033] The intermediate cylindrical portion 27 is formed with a slit 40 that extends in the axial direction from the opening 31 toward the base portion 21 and allows the viscous fluid N to flow therethrough.

[0034] In this embodiment, a slit 40 is formed at one location around the circumference of the outer tube portion 25, that is, as shown in Figure 3, when the first rotating member 20 is viewed from the axial direction, at a position that passes through a line L connecting a predetermined pair of locking protrusions 33, 33 arranged opposite each other around the circumference of the outer tube portion 25 and the axis C of the first rotating member 20 (the center of rotation of the first rotating member 20).

[0035] 4, the slit 40 is formed by cutting out a predetermined length from the tip of the intermediate cylindrical portion 27 toward the base 21 along (parallel to) the axis C of the first rotating member 20. Furthermore, the slit 40 has a constant width from one end (the upper end in FIG. 4) to the other end (the lower end in FIG. 4), and is formed perpendicular to the surface direction of the base 21.

[0036] As shown in FIG. 3 , a slit shortening portion 45 is formed in the intermediate tubular portion 27 at a position that is aligned circumferentially with the slit 40, and that shortens the axial length of the slit 40 from the base 21 toward the opening 31.

[0037] That is, by forming the slit shortening portion 45, one end of the slit 40 coincides with the most distal end of the intermediate tubular portion 27, but the other end of the slit 40 has an axial length that stops at a point halfway along the axial direction without extending all the way to the very base end of the intermediate tubular portion 27. As a result, the slit 40 is shorter than a slit that is formed to extend from the very tip to the very base end of the intermediate tubular portion 27.

[0038] The slit shortening portion can also be defined as "a position of the intermediate tubular portion that is aligned circumferentially with the slit, and extends from the base toward the opening, and the slit shortening portion forms the axial length of the slit from the tip end of the slit shortening portion in the extension direction to the opening to be shorter than the extension length of the intermediate tubular portion."

[0039] That is, as will be described later, the slit shortening portion may be arranged so that both circumferential sides or one circumferential side thereof are spaced apart from the intermediate tubular portion to form a gap, but in such a case, the slits will consist of a wide slit formed in the range from the tip of the slit shortening portion in the extension direction to the opening, and a narrow slit narrower (shorter in circumferential length) than the wide slit formed in the range from the base to the tip of the slit shortening portion in the extension direction, which are connected in the extension direction of the intermediate tubular portion. In this case, the axial length of the slit means the axial length of the wide slit, of the wide slit and narrow slit that make up the slit.

[0040] The apex 46 of the slit shortening portion 45 has an axial height H that coincides with the other end of the slit 40. Furthermore, as shown in Fig. 4, both end edges 46a, 46a of the apex 46 of the slit shortening portion 45 in the thickness direction (the direction along the arrangement direction of the radially adjacent annular spaces 29, 30 in the axial cross section) have a rounded R-shape. The axial height H of the slit shortening portion 45 means the height of the slit shortening portion 45 from the inner surface of the base 21 (the surface facing the tip surfaces of the cylindrical portions 53, 55 of the second rotating member 50) to the apex 46.

[0041] 3, both circumferential side portions 47, 47 of the slit shortening portion 45 are connected to the intermediate tubular portion 27. That is, in this embodiment, both circumferential side portions 47, 47 of the slit shortening portion 45 (a direction along the circumferential direction of the intermediate tubular portion 27 of the slit shortening portion 45; this can also be said to be the width direction) are configured so that there is no gap between them and the intermediate tubular portion 27 at the location where the slit shortening portion 45 is formed.

[0042] Furthermore, the height of the slit shortening portion 45 from the base 21, i.e., the axial height H of the slit shortening portion 45, is set so as to be higher than the liquid level (which can also be said to be the surface or upper surface of the viscous fluid N) of the viscous fluid N filled in the annular spaces 29, 30 before the corresponding tubular portions 53, 55 of the second rotating member 50 are inserted into each annular space 29, 30 of the first rotating member 20.

[0043] In this embodiment, in the above state, the axial height H of the slit shortening portion 45 is higher than the liquid level of the viscous fluid N with the larger amount filled between the annular spaces 29, 30 defined on both radial sides of the intermediate cylindrical portion 27 in which the slit shortening portion 45 is formed (here, the liquid level of the viscous fluid N filled in the second annular space 30).

[0044] When assembling the first rotating member 20 and the second rotating member 50, the corresponding cylindrical portions 53, 55 of the second rotating member 50 are inserted into the annular spaces 29, 30 of the first rotating member 20 (see Figures 5 to 7), but at this time, the annular spaces 29, 30 of the first rotating member 20 are filled with a viscous fluid N beforehand (see Figure 5).

[0045] 5 , the second annular space 30 is filled with a larger amount of viscous fluid N than the first annular space 29 (assuming that the viscous fluid N is filled in the two annular spaces 29, 30 in the same amount, the liquid level of the viscous fluid N in the first annular space 29 is higher than the liquid level of the viscous fluid N in the second annular space 30). In this case, the axial height H of the slit shortening portion 45 is set so that the liquid level of the viscous fluid N filled in the second annular space 30 does not exceed the top 46 of the slit shortening portion 45.

[0046] As a result, the viscous fluid N filled in the second annular space 30 is prevented from flowing over the top 46 of the slit shortening portion 45 into the first annular space 29. Similarly, the viscous fluid N filled in the first annular space 29 is prevented from flowing over the top 46 of the slit shortening portion 45 into the second annular space 30.

[0047] Next, the second rotating member 50 constituting the braking member 11 will be described with reference to FIGS. 1, 2, 5, etc.

[0048] The second rotating member 50 has a substantially annular plate-shaped closing portion 51 that closes the opening 31 of the first rotating member 20, an inner cylindrical portion 53 that extends a predetermined length from the inner peripheral edge of the closing portion 51 in a direction toward and away from the first rotating member 20, and an outer cylindrical portion 55 that extends a predetermined length from the outer peripheral edge of the closing portion 51 concentrically with the corresponding inner cylindrical portion 53 in a direction toward and away from the first rotating member 20. In other words, the second rotating member 50 has a double cylindrical structure in which the cylindrical portions 53, 55, 27 are concentrically and coaxially arranged.

[0049] In addition, the inner tube portion 53 and the outer tube portion 55 are formed so that the extension amount in the direction from the blocking portion 51 toward the first rotating member 20 is greater than the extension amount in the direction from the blocking portion 51 away from the first rotating member 20.

[0050] A stepped ring arrangement portion 53a (see FIG. 5) is formed on the inner periphery of the inner cylindrical portion 53 near the blocking portion 51. A first seal ring S1 is interposed near this ring arrangement portion 53a.

[0051] Furthermore, a base end 55a of the outer tubular portion 55 in the extending direction (a portion spaced from the base portion 21 of the first rotating member 20 and near the blocking portion 51) has a larger diameter than the remaining portions, and an annular ring mounting groove 55b is formed in the outer peripheral surface of the base end 55a. A second seal ring S2 is mounted in this ring mounting groove 55b. The outer periphery of this second seal ring S2 abuts against the inner periphery of the outer tubular portion 25 of the first rotating member 20 to seal the viscous fluid filled inside the braking member 11 (see FIG. 8).

[0052] 1 and 5, an annular projection 55c is provided on the outer periphery of the base end 55a of the outer cylindrical portion 55, closer to the base end than the ring mounting groove 55b. This annular projection 55c engages with the retaining portion 38 of the first rotating member 20, thereby preventing the second rotating member 50 from coming off the first rotating member 20 in the axial direction.

[0053] Furthermore, a pair of connecting projections 56, 56 protrude in the axial direction of the braking member 11 from the base end side of the inner cylindrical portion 53 (the side away from the base portion 21 of the first rotating member 20) and the base end portion 55a side of the outer cylindrical portion 55, at locations that face each other in the radial direction of the first rotating member 20. The pair of connecting projections 56, 56 clamp the connected portion 5 of the first member 1 (see FIG. 16 ), thereby connecting the second rotating member 50 to the first member 1 so that it does not rotate relative to the first member 1.

[0054] As shown in Fig. 12, communicating holes 57, 57 are formed in opposing circumferential positions of the inner cylindrical portion 53. Communicating holes 57, 57 are also formed in opposing circumferential positions of the outer cylindrical portion 55. Furthermore, the communicating holes 57 formed in both cylindrical portions 53, 55 are aligned in the circumferential direction of both cylindrical portions 53, 55. Furthermore, as shown in Fig. 5, a plurality of communicating holes 57 are formed in both cylindrical portions 53, 55 at predetermined intervals in the axial direction of the second rotating member 50.

[0055] Each communication hole 57 allows the viscous fluid N filled in the braking member 11, air bubbles generated in the viscous fluid N due to the rotational movement of the braking member 11, or air bubbles that have become contained in the viscous fluid N due to air remaining in the annular spaces 29, 30 to circulate.

[0056] 5 and 12, a plurality of axial grooves 58a (four in this example) extending in the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface of the inner cylindrical portion 53 (the surface facing the outer cylindrical portion 55) and the outer peripheral surface of the outer cylindrical portion 55 (the surface opposite the surface facing the inner cylindrical portion 53), at positions that align in the circumferential direction of both cylindrical portions 53, 55. Of the four axial grooves 58a formed in both cylindrical portions 53, 55, a pair of axial grooves 58a, 58a that face each other in the radial direction are provided at positions that align with the communicating holes 57.

[0057] 12, a plurality of axial grooves 58b (four in this example) extending in the axial direction are formed at equal intervals in the circumferential direction on the inner circumferential surface of the inner cylindrical portion 53 (the surface opposite to the surface facing the outer cylindrical portion 55) and the inner circumferential surface of the outer cylindrical portion 55 (the surface facing the inner cylindrical portion 53), at positions that align in the circumferential direction of both cylindrical portions 53, 55. The axial grooves 58b formed in both cylindrical portions 53, 55 are arranged so as to be located between the axial grooves 58a, 58a that are adjacent in the circumferential direction.

[0058] The axial grooves 58a and 58b are primarily intended to capture the air bubbles.

[0059] Furthermore, as shown in Figure 5, a notched groove-shaped communicating groove 59 is formed at the most distal end of the inner cylindrical portion 53 in the extension direction (the end closest to the base 21 of the first rotating member 20) to allow the viscous fluid N, etc., filled inside the braking member 11 to circulate.

[0060] Next, a method for manufacturing a rotary braking device according to the invention will be described, which is manufactured by assembling the first rotary member 20 and the second rotary member 50 having the above-described configuration.

[0061] That is, the invention of the method for manufacturing a rotary braking device includes: (1) a first filling step of filling the viscous fluid into the annular space with a larger volume or the annular space with a smaller volume among the annular spaces defined on both radial sides of the intermediate cylindrical portion in which the slit shortening portion is formed; (2) a second filling step of filling the annular space with a smaller volume among the annular spaces defined on both radial sides of the intermediate cylindrical portion in which the slit shortening portion is formed with a smaller amount of viscous fluid than in the first filling step, or filling the annular space with a larger volume than in the first filling step; and (3) a cylindrical portion insertion step of inserting the corresponding cylindrical portion of the second rotating member into each annular space of the first rotating member.

[0062] 5, the second annular space 30 having a larger volume V2 is filled with the viscous fluid N (first filling step), and the first annular space 29 having a smaller volume V1 is filled with a smaller amount of the viscous fluid N than in the first filling step (second filling step). Alternatively, the first annular space 29 having a smaller volume V1 is filled with the viscous fluid N (first filling step), and the second annular space 30 having a larger volume V2 is filled with a larger amount of the viscous fluid N than in the first filling step (second filling step). The first and second filling steps may be performed simultaneously.

[0063] Then, seal rings S1 and S2 are attached to the inner cylinder portion 23 of the first rotating member 20 and the outer cylinder portion 55 of the second rotating member 50, respectively, and as shown in the upper part of Figure 5, the inner cylinder portion 53 of the second rotating member 50 is aligned with the first annular space 29 of the first rotating member 20, and the outer cylinder portion 55 of the second rotating member 50 is aligned with the second annular space 30 of the first rotating member 20.

[0064] Next, as shown by the arrows in Figure 5, the second rotating member 50 is pushed against the first rotating member 20, and the corresponding cylindrical portions 53, 55 of the second rotating member 50 are inserted into the annular spaces 29, 30 of the first rotating member 20 from the opening 31 of the first rotating member 20 (see Figure 6).

[0065] Thereafter, when the second rotating member 50 is further pressed against the first rotating member 20, the viscous fluid N filled in the annular spaces 29, 30 is pushed by the cylindrical portions 53, 55 of the second rotating member 50 and gradually rises within the annular spaces 29, 30, and the viscous fluid N passes over the top 46 of the slit shortening portion 45 and flows through the slit 40 or the communicating hole 57 (see Figure 7).

[0066] When the second rotating member 50 is further pushed in and the annular protrusion 55c of the second rotating member 50 overcomes the multiple anti-slip portions 38 of the first rotating member 20, the multiple anti-slip portions 38 engage with the annular protrusion 55c and press down on the annular protrusion 55c, thereby assembling the second rotating member 50 to the first rotating member 20 in a state where it is prevented from coming off in the axial direction (this is the end of the tubular portion insertion process).

[0067] 9 and 10 , when the two rotating members 20, 50 are assembled as described above, the inner cylindrical portion 53 of the second rotating member 50 is rotatably inserted into the first annular space 29 between the inner cylindrical portion 23 and the intermediate cylindrical portion 27 of the first rotating member 20, and the outer cylindrical portion 55 of the second rotating member 50 is rotatably inserted into the second annular space 30 between the outer cylindrical portion 25 and the intermediate cylindrical portion 27 of the first rotating member 20. As a result, the first rotating member 20 and the second rotating member 50 are supported so as to be rotatable relative to each other.

[0068] Furthermore, as described above, when the first rotating member 20 and the second rotating member 50 are assembled, the viscous fluid N fills the entire first annular space 29 and the second annular space 30, and is sealed by the first seal ring S1 and the second seal ring S2, as shown in Figure 8.

[0069] More specifically, the viscous fluid N is filled into the gaps between radially adjacent cylindrical portions, namely, (1) the gap between the inner cylindrical portion 23 of the first rotating member 20 and the inner cylindrical portion 53 of the second rotating member 50, (2) the gap between the inner cylindrical portion 53 of the second rotating member 50 and the intermediate cylindrical portion 27 of the first rotating member 20, (3) the gap between the intermediate cylindrical portion 27 of the first rotating member 20 and the outer cylindrical portion 55 of the second rotating member 50, (4) the gap between the outer cylindrical portion 55 of the second rotating member 50 and the outer cylindrical portion 25 of the first rotating member 20, (5) the gap between the base portion 21 of the first rotating member 20 and the tip ends of both cylindrical portions 53, 55 of the second rotating member 50, and (6) the slits 40, the communicating holes 57, the axial grooves 58a, 58b, the communicating grooves 59, etc.

[0070] In this embodiment, the radial dimensions of the gaps (1) to (4) are all the same, as shown in Fig. 10. For convenience, the viscous fluid N is omitted from Figs. 9 and 10.

[0071] When the two rotating members 20, 50 rotate relative to each other, that is, when the second rotating member 50 rotates relative to the first rotating member 20 in a predetermined direction or the opposite direction, or when the first rotating member 20 rotates relative to the second rotating member 50 in a predetermined direction or the opposite direction, the viscous fluid N filled in each gap as described above (mainly the viscous fluid N filled in the gaps (1) to (4)) is sheared at each location, and the shear resistance causes the braking member 11 to exert a braking force.

[0072] Furthermore, as shown in Figures 1, 2, 12 to 15, etc., the rotary braking device 10 in this embodiment has a third rotating member 15 that is rotatably mounted coaxially to the braking member 11 via a rotation support portion, and an oscillating rotating member 80 that is connected to the second member 6 and supported oscillatingly relative to the third rotating member 15 via a swing support portion described below, and is arranged on the outer periphery of the second rotating member 50.

[0073] The third rotating member 15 is made up of a first case 60 and a second case 70 arranged opposite the first case 60 (see FIG. 1). The oscillating rotating member 80 has a second engaging portion 90 (see FIG. 11) that is movably engaged with the first engaging portion 35 formed on the first rotating member 20.

[0074] In addition, the rotary braking device 10 of this embodiment is configured so that the oscillating direction of the oscillating rotating member 80 changes (or the oscillating direction switches) depending on the rotation direction of the other member (second member 6) (see arrow Y1 in Figure 15 and arrow Y2 in Figure 13).

[0075] That is, when the other member (second member 6) rotates in a predetermined direction (see arrow R1 in Figure 15) relative to one member (first member 1), the oscillating rotation member 80 oscillates (see arrow Y1 in Figure 15) in the direction in which the second engagement portion 90 engages with the first engagement portion 35 (see Figure 12), and the first rotation member 20 and the oscillating rotation member 80 rotate together (see Figures 12 and 13).

[0076] The predetermined rotation direction of the second member 6 relative to the first member 1 is referred to as the "rotation direction R1" or "R1 direction" (see FIG. 15). Also, the direction in which the oscillating rotation member 80 oscillates relative to the third rotation member 15 in the direction in which the second engagement portion 90 engages with the first engagement portion 35 is referred to as the "oscillating direction Y1" or "Y1 direction" (see FIG. 15).

[0077] On the other hand, when the other member (second member 6) rotates in the opposite direction to the predetermined direction relative to one member (first member 1) (see arrow R2 in Figure 13), the oscillating rotation member 80 oscillates (see arrow Y2 in Figure 13) in the direction in which the second engagement portion 90 moves away from the first engagement portion 35 (see Figure 14), and the oscillating rotation member 80 rotates freely relative to the first rotation member 20 (see Figures 14 and 15).

[0078] The direction opposite to the predetermined direction of the second member 6 relative to the first member 1 is referred to as the "rotation direction R2" or "R2 direction" (see FIG. 13). Also, the direction in which the oscillating rotation member 80 oscillates relative to the third rotation member 15 in the direction in which the second engagement portion 90 moves away from the first engagement portion 35 is referred to as the "oscillating direction Y2" or "Y2 direction" (see FIG. 13).

[0079] The first case 60 has a bottom 61 having an approximately annular plate shape, a peripheral wall 62 having an approximately annular shape standing upright from the outer peripheral edge of the bottom 61, and a rotating shaft 63 having an approximately cylindrical shape extending a predetermined length from the inner peripheral edge of the bottom 61.

[0080] The rotating shaft 63 has a substantially cylindrical base 63a, a pair of bifurcated flexible pieces 63b extending from the tip of the base 63a, and claws 63c projecting from the outer surface of the tip of each flexible piece 63b. A support shaft 9 (see FIG. 16) for rotatably supporting the pair of members 1 and 6 is inserted into the inner periphery of the rotating shaft 63.

[0081] Then, the rotating shaft portion 63 is inserted into the inner tube portion 23 of the first rotating member 20 that constitutes the braking member 11, while bending and deforming the flexible piece 63b, and the claw portions 63c, 63c that come out from the tip opening of the inner tube portion 23 engage with the tip surface of the tip portion 23a of the inner tube portion 23 (see Figure 10), thereby holding the first case 60 in place relative to the braking member 11, and ultimately the entire third rotating member 15 in place relative to the braking member 11, and rotatably attaching the third rotating member 15 to the first rotating member 20.

[0082] That is, in this embodiment, the first rotating member 20 and the third rotating member 15 are supported so as to be rotatable relative to each other by the inner tube portion 23 of the first rotating member 20 and the rotating shaft portion 63 provided on the first case 60 that constitutes the third rotating member 15.

[0083] As described above, the first rotating member 20 and the second rotating member 50 are supported for relative rotation by the cylindrical portions 23, 25, and 27 of the first rotating member 20 and the cylindrical portions 53 and 55 of the second rotating member 50, and these cylindrical portions 23, 25, 27, 53, and 55 are arranged coaxially (have the same rotation axis) with the rotating shaft portion 63. The rotation axis of each of these portions is also the same as the rotation axis of the support shaft 9 that rotatably supports the pair of members 1 and 6.

[0084] That is, in this embodiment, the cylindrical portions 23, 25, 27 of the first rotating member 20, the cylindrical portions 53, 55, 37 of the second rotating member 50, and the rotating shaft portion 63 of the first case 60 constitute the above-mentioned "rotation support portion."

[0085] Furthermore, a bulging portion 65 that bulges out from the outer periphery of the peripheral wall portion 62 is provided at a predetermined location in the circumferential direction of the peripheral wall portion 62. An eccentric shaft support portion 66 in the form of a circular hole is formed at a corresponding location of the bulging portion 65 and the peripheral wall portion 62.

[0086] Furthermore, elastically deformable elastic contact portions 67 are provided on the bottom portion 61 via a pair of slits 67a, 67a at locations that face each other in the radial direction of the bottom portion 61. These elastic contact portions 67 elastically contact the outer surface (the surface facing the first case 60) of the base portion 21 of the first rotating member 20 (see FIG. 10 ), thereby applying rotational resistance to the first case 60.

[0087] On the other hand, the second case 70 has a generally annular peripheral wall 71 that fits into the peripheral wall 62 of the first case 60, and a bulge 72 that bulges out from the outer periphery of the peripheral wall 71 is provided at a predetermined circumferential location on the peripheral wall 71. A circular hole-shaped eccentric shaft support portion 73 is formed in the bulge 72 (see FIG. 9 ). Furthermore, a stepped locking step 71a is formed on the inner periphery of the axial tip of the peripheral wall 71, with which the multiple locking protrusions 33 of the first rotating member 20 lock.

[0088] Next, the oscillating rotation member 80 will be described with reference to FIGS.

[0089] This oscillating rotation member 80 oscillates in a predetermined direction relative to the third rotation member 15 via the swing support portion. Furthermore, when the other member (second member 6) rotates relative to one member (first member 1), the oscillating rotation member 80 rotates and oscillates in response to the rotation of the second member 6 via the pair of connected portions 8, 8 and the connecting protrusion 83.

[0090] In this embodiment, the oscillating rotating member 80 has an annular wall portion 81 having a substantially circular ring shape, a connecting protrusion 83 protruding from the outer periphery of the annular wall portion 81 at a predetermined circumferential position, a bulge portion 85 that bulges from the outer periphery of the annular wall portion 81 at a circumferential position on the annular wall portion 81 opposite the connecting protrusion 83, and a pair of eccentric shafts 86, 87 (see Figure 9) that protrude coaxially from both thickness-wise end faces of the bulge portion 85.

[0091] The above-mentioned connecting protrusion 83 is inserted between the pair of connected portions 8, 8 of the second member 6, so that the oscillating rotation member 80 is connected to the second member 6, which is the other member.

[0092] Then, as shown in Figure 9, by inserting the eccentric shaft 86 into the eccentric shaft support portion 66 of the first case 60 and inserting the eccentric shaft 87 into the eccentric shaft support portion 73 of the second case 70, the oscillating rotating member 80 is supported so as to be able to oscillate relative to the third rotating member 15 while being sandwiched between the first case 60 and the second case 70.

[0093] That is, the eccentric shaft support portions 66, 73 of the third rotating member 15 and the eccentric shafts 86, 87 of the oscillating rotating member 80 constitute the "swing support portion" in this embodiment. Furthermore, the axis of the swing support portion does not coincide with the rotation axis of the rotation support portion, but is displaced (eccentric) radially outward from the first rotating member 20 and the third rotating member 15. Furthermore, the swing support portion is disposed outside the first rotating member 20.

[0094] Also, as shown in Figure 11, the inner circumference of the oscillating rotating member 80 is provided with a second engaging portion 90 consisting of a plurality of second engaging teeth 91 that can be engaged with and separated from a plurality of first engaging teeth 36 that constitute the first engaging portion 35 provided on the first rotating member 20.

[0095] Next, the operation of the rotation braking device 10 having the above structure will be described.

[0096] Figure 15 shows the state when the second member 6 rotates in the direction R2 relative to the first member 1, that is, when the second member 6 is grasped and lifted by hand, the second member 6 opens from the opening 4 of the first member 1 and is positioned perpendicular to the surface direction of the first member 1.

[0097] In this state, a predetermined portion of the tip end 25a of the outer tube portion 25 of the first rotating member 20 abuts against the inner circumference of the oscillating rotating member 80 (the inner circumference of the annular wall portion 81), thereby restricting the first engaging portion 35 from abutting against the inner circumference of the oscillating rotating member 80 and maintaining the first engaging portion 35 and the second engaging portion 90 in a spaced-apart state (see Figure 15).

[0098] When the second member 6 is released in the above state, the second member 6 rotates due to its own weight or the like in a direction that moves closer to the first member 1 and closes the opening 4, i.e., in the R1 direction. Following the rotation of the second member 6, the oscillating rotation member 80 then oscillates in the Y1 direction relative to the third rotation member 15 via the swing support portion. As a result, the second engagement portion 90 of the oscillating rotation member 80 engages with the first engagement portion 35 of the first rotation member 20, as shown in FIG.

[0099] 13 , when the second engaging portion 90 and the first engaging portion 35 engage with each other, the first rotating member 20 and the oscillating rotating member 80 rotate integrally in the same rotational direction R1 as the rotational direction R1 of the second member 6. As a result, the first rotating member 20 rotates in the same direction as the rotational direction R1 of the second member 6 relative to the second rotating member 50 that is connected and fixed to the first member 1, and a braking force is generated in the braking member 11, making it possible to brake the second member 6.

[0100] Next, the opening 4 of the first member 1 is blocked by the second member 6, and the surface direction of the second member 6 is horizontal. Then, the second member 6 is grasped and lifted, and rotated in the R2 direction, which is opposite to the R1 direction, relative to the first member 1, as shown in Figure 13.

[0101] Then, following the rotation of the second member 6, the oscillating rotation member 80 oscillates in the Y2 direction relative to the third rotation member 15 via the swing support portion. That is, the swing direction of the oscillating rotation member 80 relative to the third rotation member 15 changes from the Y1 direction to the Y2 direction (the swing direction is switched).

[0102] As a result, as shown in Figure 14, the multiple second engagement teeth 91 of the second engagement portion 90 of the oscillating rotating member 80 move away from the multiple first engagement teeth 36 of the first engagement portion 35 of the first rotating member 20, and the engagement between the first engagement portion 35 and the second engagement portion 90 is released.

[0103] In addition, a predetermined portion of the tip end 25a of the outer tube portion 25 of the first rotating member 20 abuts against the inner circumference of the annular wall portion 81 of the oscillating rotating member 80, thereby restricting the first engaging portion 35 from abutting against the inner circumference of the oscillating rotating member 80 and maintaining the first engaging portion 35 and the second engaging portion 90 in a spaced-apart state (see Figure 14).

[0104] Therefore, when the second member 6 is further lifted upward and rotated relative to the first member 1, the oscillating rotation member 80 rotates freely (spins idly) relative to the first rotation member 20. Therefore, as shown in Fig. 15, even if the second member 6 is rotated relative to the first member 1 until the second member 6 is disposed perpendicular to the surface direction of the first member 1, it is possible to rotate the second member 6 without the braking force of the braking member 11 acting on it.

[0105] If the hand is released from the second member 6 in this state, the second member 6 rotates in the R1 direction, and the swingable rotation member 80 swings in the Y1 direction relative to the third rotation member 15 via the swing support portion, as explained in paragraph 0095, and the swing direction of the swingable rotation member 80 relative to the third rotation member 15 changes (switches) again from the Y2 direction to the Y1 direction. The subsequent operation is the same as that explained in paragraph 0095 and thereafter.

[0106] (Variant example) The shapes, structures, layouts, etc. of the braking members (first rotating member and second rotating member), third rotating member, oscillating rotating member, seal ring, etc. that constitute the rotary braking device of the present invention are not limited to the above-mentioned embodiments.

[0107] In the case of the rotary braking device 10 of this embodiment, in addition to the first rotating member 20 and the second rotating member 50, it is configured to have a third rotating member 15 and an oscillating rotating member 80, but the rotary braking device may not have the third rotating member 15 and the oscillating rotating member 80 as described above, and may instead have only the first rotating member and the second rotating member, for example, by being directly incorporated inside both ends of the assist grip.

[0108] Furthermore, the rotational braking device 10 of this embodiment is a so-called one-way rotational braking device (also called a one-way rotational braking device) in which, for a pair of members 1, 6 that rotate relative to one another, a braking force is applied when the second member 6 rotates in a predetermined R1 direction relative to the first member 1, but no braking force is applied when the second member 6 rotates in the R2 direction opposite to the R1 direction relative to the first member 1, but it may also be configured to apply a braking force when rotating in both the R1 and R2 directions.

[0109] Furthermore, in the case of the rotational braking device 10 of this embodiment, when the second member 6 approaches the first member 1 (when closing the opening 4 of the first member 1), a braking force is applied to the second member 6 to slowly approach it (close it slowly), but it may also be used in a rotational structure of a so-called free-stop hinge in which a braking force is applied when both members rotate so that the second member can be maintained in a stationary (stopped) state at a predetermined angle relative to the horizontal direction.

[0110] In addition, although only one intermediate cylindrical portion 27 is provided on the first rotating member 20 in this embodiment, two or more intermediate cylindrical portions may be provided on the first rotating member.

[0111] Furthermore, although the slit 40 in this embodiment is formed at one location in the circumferential direction of the intermediate cylindrical portion 27, the slit may be formed at two or more locations in the intermediate cylindrical portion. Note that when two or more intermediate cylindrical portions are provided, it is sufficient that a slit is formed in at least one intermediate cylindrical portion, but a slit may be formed in each of the multiple intermediate cylindrical portions, or a slit may be formed in only a specific intermediate cylindrical portion (for example, when three intermediate cylindrical portions are provided, a slit may be formed in two of the intermediate cylindrical portions).

[0112] Furthermore, although the slits 40 in this embodiment are formed parallel to the axis C of the first rotating member 20, the slits may be formed inclined at a predetermined angle relative to the axis of the first rotating member.

[0113] Furthermore, in this embodiment, both widthwise sides of the slit shortening portion 45 are connected to the intermediate tubular portion 27, but both widthwise sides or one widthwise side of the slit shortening portion may be arranged so as to be spaced apart from the intermediate tubular portion to form a gap (which may also be called a narrow slit).

[0114] In addition, in this embodiment, the two seal rings S1 and S2 seal the viscous fluid N within the brake member 11, i.e., prevent leakage of the viscous fluid N from the two annular spaces 29 and 30, but it is also possible to use a configuration in which the viscous fluid N is sealed with only one seal ring (this will be described in the embodiment described later).

[0115] (Operation and Effect) Next, the operation and effect of the rotation braking device 10 configured as described above will be described.

[0116] That is, a slit 40 is formed in the intermediate cylindrical portion 27 of the first rotating member 20, but a slit shortening portion 45 that shortens the slit 40 is formed at a position that is aligned circumferentially with this slit 40.

[0117] As described above, by forming a slit shortening portion 45 in the intermediate tubular portion 27 of the first rotating member 20 that shortens the axial length of the slit 40, the slit shortening portion 45 is positioned opposite a specified tubular portion of the second rotating member 50, so that the area of ​​the portion of the intermediate tubular portion 27 that axially overlaps with the specified tubular portion of the second rotating member 50 can be increased at a position that is circumferentially aligned with the slit 40.

[0118] Specifically, since the slit shortening portion 45 is positioned opposite both tubular portions 53, 55 of the second rotating member 50, the area of ​​the axial overlapping portion of the intermediate tubular portion 27 of the first rotating member 20 with both tubular portions 53, 55 of the second rotating member 50 can be increased.

[0119] As a result, when the first rotating member 20 and the second rotating member 50 rotate relative to each other, the viscous fluid N does not escape from the slit 40 to the extent that the slit shortening portion 45 is provided, and the viscous fluid N remains in the slit shortening portion 45.

[0120] This mainly increases the shear resistance caused by shearing of the viscous fluid N in the gap between the intermediate cylindrical portion 27 of the first rotating member 20 and the inner cylindrical portion 53 of the second rotating member 50, and the viscous fluid N in the gap between the intermediate cylindrical portion 27 of the first rotating member 20 and the outer cylindrical portion 55 of the second rotating member 50, thereby improving the braking force of the rotary braking device 10.

[0121] Furthermore, while the slit 40 is shortened by the slit shortening portion 45, the slit 40 itself is maintained, so that the flow of viscous fluid N and the flow of air bubbles between the radially adjacent annular spaces 29, 30 are not hindered.

[0122] However, when assembling the first rotating member 20 and the second rotating member 50 by inserting the corresponding tubular portions 53, 55 of the second rotating member 50 into the annular spaces 29, 30 of the first rotating member 20, there have been cases where the amount of viscous fluid N filled into each annular space 29, 30 became uneven due to leakage of the viscous fluid N from a predetermined annular space through the slits 40 before the second rotating member 50 was inserted into the first rotating member 20. In this case, there is a risk that insertion resistance will increase when the corresponding tubular portions 53, 55 of the second rotating member 50 are inserted into the annular spaces 29, 30 of the first rotating member 20.

[0123] In contrast to this, in this rotational braking device 10, by forming the slit shortening portion 45 in the intermediate cylindrical portion 27 of the first rotating member 20 as described above, when the viscous fluid N is filled in a predetermined annular space of the first rotating member 20, it is possible to make it difficult for the viscous fluid N to flow into other annular spaces. In other words, it is possible to suppress the inflow of the viscous fluid N from the first annular space 29 to the second annular space 30, and the inflow of the viscous fluid N from the second annular space 30 to the first annular space 29.

[0124] Therefore, it becomes easier to fill a specified annular space with the desired amount of viscous fluid N, and the amount of viscous fluid N filled in each annular space 29, 30 can be adjusted appropriately, so that the increase in insertion resistance when assembling the two rotating members 20, 50 as described above can be suppressed, and the ease of assembly of the first rotating member 20 and the second rotating member 50 can be improved.

[0125] In this embodiment, both circumferential side portions 47 , 47 of the slit shortening portion 45 are connected to the intermediate cylindrical portion 27 of the first rotating member 20 .

[0126] According to the above aspect, since both circumferential side portions 47, 47 of the slit shortening portion 45 are connected to the intermediate tubular portion 27, a configuration can be achieved in which there are no gaps between the both circumferential side portions 47, 47 of the slit shortening portion 45.

[0127] As a result, the area of ​​the overlapping portion of the intermediate tubular portion 27 of the first rotating member 20 with both tubular portions 53, 55 of the second rotating member 50 can be increased in the width direction (which can also be said to be the direction along the circumferential direction), thereby further increasing the shear resistance of the viscous fluid N and further improving the braking force of the rotary braking device 10.

[0128] Furthermore, since the amount of viscous fluid N filled into a specified annular space can be reliably adjusted, the increase in insertion resistance when inserting the corresponding tubular portions 53, 55 of the second rotating member 50 into each annular space 29, 30 of the first rotating member 20 can be further suppressed, thereby further improving the ease of assembly of the first rotating member 20 and the second rotating member 50.

[0129] Furthermore, in this embodiment, the height (axial height H) of the slit shortening portion 45 from the base 21 is set to be higher than the liquid level of the viscous fluid N filled in the annular spaces 29, 30 before the corresponding cylindrical portions 53, 55 of the second rotating member 50 are inserted into each annular space 29, 30 of the first rotating member 20.

[0130] According to the above aspect, the height of the slit shortening portion 45 from the base 21 is set as described above, so that when the corresponding cylindrical portions 53, 55 of the second rotating member 50 are inserted into each annular space 29, 30 of the first rotating member 20, the viscous fluid N filled in a specified annular space can be reliably retained within the annular space 29, 30 and prevented from overflowing.

[0131] As a result, the increase in insertion resistance when inserting the corresponding tubular portions 53, 55 of the second rotating member 50 into each annular space 29, 30 of the first rotating member 20 can be further suppressed, and the ease of assembly of the first rotating member 20 and the second rotating member 50 can be further improved.

[0132] (Second embodiment of the rotary braking device) Another embodiment of the rotary braking device according to the present invention is shown in Fig. 17. Note that parts that are substantially the same as those in the above embodiment are given the same reference numerals and their description will be omitted.

[0133] The rotary braking device 10A of this embodiment basically has the same structure as the above-mentioned embodiment, but differs from the above-mentioned embodiment in that it has only one seal ring.

[0134] 17, the tip of the inner cylindrical portion 23 of the first rotating member 20A in the extending direction is closed by an annular closing plate 48. On the other hand, a closing plate 52 is provided in the closing portion 51 of the second rotating member 50A at a position opposite to the closing plate 48 of the first rotating member 20A.

[0135] Therefore, when the first rotating member 20A and the second rotating member 50A are assembled, the viscous fluid N is also filled into the gap between the closure plate 48 of the first rotating member 20A and the closure plate 52 of the second rotating member 50A (for convenience, the viscous fluid N is omitted in Figure 17).

[0136] As a result, in this rotary braking device 10A, the first seal ring S1 interposed on the inner cylindrical portion 23 of the first rotating member 20, which was necessary in the rotary braking device 10 of the above embodiment, is not necessary, and only the second seal ring S2 is sufficient, so the number of seal rings can be reduced, which has the effect of reducing the effort required for parts management and reducing the manufacturing cost of the rotary braking device 10A.

[0137] Furthermore, the present invention is not limited to the above-described embodiments, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention.

[0138] REFERENCE SIGNS LIST 10, 10A Rotation braking device 11 Braking member 15 Third rotating member 20, 20A First rotating member 21 Base portion 23 Inner cylindrical portion 25 Outer cylindrical portion 27 Intermediate cylindrical portion 29 First annular space 30 Second annular space 31 Opening portion 40 Slit 45 Slit shortening portion 50, 50A Second rotating member 51 Closure portion 53 Inner cylindrical portion 55 Outer cylindrical portion 60 First case 70 Second case 80 Oscillating rotating member

Claims

1. A rotary braking device disposed between a pair of members that rotate relative to each other and that applies a braking force during the relative rotation, the rotary braking device comprising: a first rotating member; and a second rotating member rotatably assembled to the first rotating member, wherein the first rotating member includes a base portion, an inner cylindrical portion extending from inside the base portion, an outer cylindrical portion extending concentrically with respect to the inner cylindrical portion from outside the base portion, at least one intermediate cylindrical portion extending concentrically with respect to the inner cylindrical portion and the outer cylindrical portion between the inner cylindrical portion and the outer cylindrical portion of the base portion, a plurality of annular spaces defined concentrically between adjacent cylindrical portions in the radial direction and filled with a viscous fluid, and an opening disposed opposite to the base portion; the second rotating member includes a closing portion that closes the opening, and a plurality of cylindrical portions extending concentrically from the closing portion and inserted into the plurality of annular spaces; a slit is formed in the intermediate cylindrical portion and extends axially from the opening toward the base portion to allow the viscous fluid to flow through; and a slit shortening portion is formed in the intermediate cylindrical portion at a position circumferentially aligned with the slit and shortens the axial length of the slit from the base portion toward the opening.

2. The rotary braking device according to claim 1, wherein both circumferential side portions of the slit shortening portion are connected to the intermediate cylindrical portion.

3. The rotary braking device according to claim 1 or 2, wherein the height of the slit shortening portion from the base portion is provided to be higher than the liquid level of the viscous fluid filled in the annular space in a state before inserting the corresponding cylindrical portion of the second rotating member into each annular space of the first rotating member.

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