JP2024101162A - Rotary damper and combination of rotary damper and link mechanism - Google Patents

Abstract

To provide a novel rotary damper which (1) can make necessary resistance torque act on a rotating body 8 even immediately after a start of the rotation of the rotating body 8, and (2) can suppress a rotational speed of the rotating body 8 even if rotation torque acting on the rotating body 8 of the rotary damper is gradually increased.SOLUTION: (1) When a rotating body 8 rotates, a hook part 28 is relatively pressed in a direction in which the fastening of a spring member 10 is strengthened by a holding member 12. (2) A link mechanism 6 is combined to a rotary damper 4, a single-side movable section P1 for connecting a single-side link piece 54 and an intermediate link piece 58 approaches a rotating shaft o1 while turning around an eccentric shaft o2, and the other side link piece 56 is rotated.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotary damper and a combination of a rotary damper and a link mechanism.

Rotary dampers that apply a required resistance torque to a rotor to suppress the rotation speed of the rotor are already widely used. For example, rotary dampers are incorporated in the winding mechanism of blinds installed near a window in a room, and suppress the falling speed when the bottom rail connected to the winding mechanism falls freely in the vertical direction. In this case, the rotor of the rotary damper is rotated continuously in one direction, and the magnitude of the rotation torque applied to the rotor is constant. Rotary dampers are also connected to external equipment (rotating members) that can rotate between open and closed positions, such as the toilet lid and valve seat of a Western-style toilet or the cover of a copying machine, and may suppress the rotation speed when the device rotates and closes due to gravity from the open position to the closed position. In this case, the rotor of the rotary damper is rotated only within a relatively narrow required angle range, and the magnitude of the rotation torque applied to the rotor changes depending on the rotation angle position of the external device. Rotary dampers used in the latter way are sometimes called swing dampers.

The mainstream rotary damper is the so-called oil damper, which uses the viscous resistance of a relatively viscous fluid such as silicon oil sealed inside the housing. However, oil dampers have problems in that the sealed fluid can leak to the outside, and the viscous resistance of the fluid is easily affected by temperature, so performance can vary depending on the operating temperature.

To solve the above problem, the applicant of the present application has devised a rotary damper that uses a spring member formed by winding a wire rod without using the viscous resistance of a fluid. This rotary damper was filed by the applicant of the present application prior to the present application and has already been patented (Patent Document 1 below). Patent Document 1 below shows a rotary damper that includes a rotating body with a mounting part having a circular cross section, a spring member formed by winding a wire rod in a spiral shape multiple times and mounted on the outer circumferential surface of the mounting part of the rotating body, and a fixed holding member, the spring member has a hook portion, the hook portion is held by the holding member so that the spring member cannot rotate relative to the holding member, and when the rotating body rotates, the hook portion is pushed by the holding member relatively in a direction in which the tightening of the spring member is weakened, causing the rotating body to slide against the spring member, and the rotating body is formed of a synthetic resin material that has the property that the frictional force between the rotating body and the spring member increases as the rotation speed relative to the spring member increases.

Patent No. 7088993

The rotary damper shown in the above-mentioned Patent Document 1 has the following problems to be solved. That is, (1) Immediately after the rotation of the rotor starts, the hook portion bends excessively in the loosening direction due to inertia, causing the inner diameter of the spring member to expand excessively, resulting in a time delay before the rotor rotates under the required resistance torque. Also, (2) For example, when incorporated into a blind winding mechanism, the falling speed of the bottom rail when it falls freely in the vertical direction can be sufficiently suppressed, but when connected to an external device that swings and closes from the open position to the closed position due to gravity, the swing speed of the external device cannot be sufficiently suppressed. This is because in the former case, a constant force due to gravity acts on the bottom rail that falls freely in the vertical direction, so the magnitude of the rotation torque acting on the rotor of the rotary damper is constant, but in the latter case, the rotation torque acting on the rotor of the rotary damper gradually increases as the external device swings and closes from the open position to the closed position. This will be mentioned in more detail later.

The present invention was made in consideration of the above facts, and its first objective is to provide a new and improved rotary damper that can apply the required resistance torque to a rotating body even immediately after the rotating body starts to rotate.

The second object of the present invention is to suppress the rotational speed of the rotor even when the rotational torque acting on the rotor of the rotary damper gradually increases.

After extensive research, the inventors have found that the first problem can be solved by making the hook portion relatively pushed by the retaining member in a direction that strengthens the tightening of the spring member when the rotating body rotates. They have also found that the second problem can be solved by combining a link mechanism with the rotary damper to reduce the magnitude of the rotational torque acting on the rotating body of the rotary damper.

That is, according to the present invention, a rotary damper that solves the first problem described above includes a rotor having a mounting portion having a circular cross section, a spring member formed by winding a wire in a spiral shape and mounted on the mounting portion of the rotor, and a fixed holding member,
the spring member has a hook portion, and the hook portion is held by the holding member, so that the spring member cannot rotate with respect to the holding member;
When the rotating body rotates, the hook portion is relatively pressed by the holding member, and the rotating body slides against the spring member,
The rotary damper is formed of a synthetic resin material having a characteristic that a frictional force between the rotating body and the spring member increases as the rotational speed relative to the spring member increases,
There is provided a rotary damper characterized in that, when the rotating body rotates, the hook portion is relatively pressed by the retaining member in a direction in which the tightening of the spring member is increased.

Preferably, the number of turns of the wire forming the spring member is one. The hook portion preferably extends in the normal direction. The spring member is preferably coated with fluorine-based grease. The spring member is conveniently attached to the outer circumferential surface of the attachment portion. Preferably, a plurality of the spring members are arranged in the axial direction. The rotating body preferably rotates within a required angular range. In this case, the rotating body is preferably equipped with a one-way clutch.

Further, according to the present invention, there is provided a combination that solves the second problem described above, which is a combination of the rotary damper in which at least the rotating body rotates within a required angle range, and a link mechanism, wherein the link mechanism includes a one-side link piece that is rotatable about an eccentric shaft that is eccentric with respect to the rotation shaft of the rotating body and rotates integrally with an external device, an other-side link piece that is rotatable about the rotation shaft and rotates integrally with the rotating body, and an intermediate link piece that connects the one-side link piece and the other-side link piece,
When the external device rotates, a one-side movable joint connecting the one-side link piece and the intermediate link piece approaches the rotation axis while rotating around the eccentric shaft, causing the other-side link piece to rotate.

Preferably, each of the one-side link piece and the other-side link piece is formed with a rotation prevention means that abuts against the holding member to prevent the external device from rotating.

In the rotary damper of the present invention, when the rotor rotates, the hook portion is pushed by the retaining member in a direction that tightens the spring member, so the hook portion does not bend excessively due to inertia immediately after the rotor starts to rotate. Therefore, the rotor can rotate under the required resistance torque immediately after it starts to rotate, that is, without any time delay.

In the combination of the present invention, when the external device rotates, the one-side movable joint connecting the one-side link piece and the intermediate link piece rotates around the eccentric shaft and approaches the rotation axis, causing the other-side link piece to rotate. Since the one-side link piece rotates integrally with the external device, the rotation torque generated by the external device rotating is transmitted to the intermediate link piece by the one-side movable joint. Also, since the one-side movable joint approaches the rotation axis, the above rotation torque is reduced accordingly and transmitted to the other-side link piece. This is because, as viewed from the other-side link piece, the length of the arm from the rotation axis, which is the center of rotation, that is, the distance to the one-side movable joint, is gradually reduced. Therefore, even if the external device is rotated from the open position to the closed position by gravity and the rotation torque gradually increases, such rotation torque is gradually reduced by the link mechanism, so that even the above-mentioned rotary damper can sufficiently suppress the rotation speed of the external device.

FIG. 1 is a diagram showing the configuration of a preferred embodiment of a combination of a rotary damper and a link mechanism configured according to the present invention. FIG. 2 is a diagram showing a rotor of the rotary damper alone in the combination shown in FIG. 1 . FIG. 2 is a view showing a spring member of the rotary damper alone in the combination shown in FIG. 1 . FIG. 2 is a view showing a rotary damper holding member alone in the combination shown in FIG. 1 . 2 is a view showing one link piece of the link mechanism in the combination shown in FIG. 1 . FIG. 6 is a view showing a drive shaft connected to the one-side link piece shown in FIG. 5 alone; FIG. 2 is a view showing the other link piece of the link mechanism in the combination shown in FIG. 1 alone; FIG. 8 is a view showing a driven shaft connected to the other link piece shown in FIG. 7 alone; FIG. 2 is a view showing a single intermediate link piece of the link mechanism in the combination shown in FIG. 1 . 2 is a cross-sectional view taken along the line CC when the external device is turned to close in the combination shown in FIG. 1 .

The rotary damper constructed according to the present invention and the combination of this rotary damper with a link mechanism will be described in more detail below with reference to the attached drawings.

In Figure 1, a preferred embodiment of a combination of a rotary damper and a link mechanism constructed according to the present invention is indicated by the number 2, with the rotary damper indicated by the number 4 and the link mechanism indicated by the number 6. This combination 2 is connected to a rotating member X, which is an external device such as the lid and valve seat of a Western-style toilet or the cover of a copier, and supports it so that it can rotate between an open position and a closed position. Figure 1 shows the state in which the rotating member X is in the open position, and the rotating member X rotates and closes due to gravity to the closed position shown in Figure 10(b).

The rotary damper 4 comprises a rotating body 8, a spring member 10, and a retaining member 12. Referring to FIG. 1 and FIG. 2, the rotating body 8 is rotatable around a rotation axis o1 and is made of a synthetic resin material having a predetermined property described later. The rotating body 8 comprises a mounting portion 14 having a circular cross section. In the illustrated embodiment, the mounting portion 14 is cylindrical, that is, the cross section of the outer circumferential surface of the mounting portion 14 is circular. A ring-shaped flange portion 16 extending radially outward is provided at one axial end of the outer circumferential surface of the mounting portion 14. The inside of the rotating body 8 penetrates in the axial direction, and a circular cross-sectional insertion hole 18 is arranged on one axial side and a support hole 20 is arranged on the other axial side, each coaxially with the rotating axis o1. The diameter of the support hole 20 is larger than the diameter of the insertion hole 18, and three support protrusions 22 extending linearly in the axial direction are formed at equal angular intervals in the circumferential direction on the inner circumferential surface of the rotating body 8 that defines the support hole 20. As shown in the A-A and B-B cross-sectional views of FIG. 1, a one-way clutch 24 is disposed in the support hole 20. The one-way clutch 24 is not hatched for easy understanding. The one-way clutch 24 cannot rotate relative to the rotating body 8 because the support protrusion 22 engages with a groove 25 formed on the outer circumferential surface of the one-way clutch 24. The one-way clutch 24 may be a well-known one, for example, the one described in Japanese Patent No. 3501352, which was filed by the applicant of the present application prior to the present application and has already been patented, and a detailed description thereof will be omitted. A driven shaft 90, which will be described later, is inserted inside the one-way clutch 24, and when the driven shaft 90 rotates counterclockwise in the A-A cross-sectional view of FIG. 1, the one-way clutch 24 rotates together with the driven shaft 90, and when the driven shaft 90 rotates clockwise, the one-way clutch 24 rotates relative to the driven shaft 90, i.e., rotates idly.

Explaining with reference to FIG. 1 and FIG. 3, the spring member 10 is formed by winding a metal wire having a circular cross section in a spiral shape, and is attached to the mounting part 14 of the rotating body 8 (in the illustrated embodiment, the outer circumferential surface thereof). In the illustrated embodiment, two spring members 10 are arranged on the mounting part 14, and each spring member 10 is coated with fluorine-based grease. The spring member 10 has a winding part 26 around which the wire is wound, and hook parts 28 and 30 from which the wire extends linearly. When viewed in the axial direction, the winding part 26 is circular, and the number of turns of the wire is one. The inner diameter of the winding part 26 in the free state is smaller than the outer diameter of the mounting part 14 of the rotating body 8, and the spring member 10 is attached to the outer circumferential surface of the mounting part 14 of the rotating body 8 with the winding part 26 expanded in diameter. In the illustrated embodiment, the hook portions 28 and 30 are provided at both ends of the wire that forms the spring member 10, with the hook portion 28 extending in the normal direction and the hook portion 30 extending in the tangential direction.

Explaining with reference to FIG. 1 and FIG. 4, the holding member 12 is made of an appropriate hard synthetic resin and is fixed to a wall or the like (not shown) by a fastening means such as a bolt. In the illustrated embodiment, the holding member 12 is cup-shaped with a rectangular end plate 32 and a square cylindrical outer wall 34 extending axially from the outer periphery of the end plate 32, and the open end of the outer wall 34 is closed by a shield plate 36 of the same shape as the end plate 32. In the A-A cross-sectional view of FIG. 1, the shield plate 36 is not hatched for easy understanding. The end plate 32 is relatively thick, and a storage recess 38 is formed on its bottom surface to store the rotating body 8 to which the spring member 10 is attached. The storage recess 38 is provided with a circular support portion 40 into which the axial end of the mounting portion 14 of the rotating body 8 is fitted and which rotatably supports it. A driven-side communicating hole 42 having a circular cross section is provided at the center of the support portion 40, which axially penetrates the end plate 32 and rotatably supports the other side portion 96 of the driven shaft 90 (described later). The accommodation recess 38 also has a hook groove 44 into which the hook portion 28 is fitted and a hook relief space 46 into which the hook portion 30 is fitted. The hook groove 44 extends linearly in the radial direction, and its groove width is the same as or slightly wider than the wire diameter of the wire material forming the spring member 10, and the hook portion 28 is held by the holding member 12 at the hook groove 44. This makes it impossible for the spring member 10 to rotate relative to the holding member 12. On the other hand, the hook relief space 46 is substantially fan-shaped, and although the hook portion 30 is fitted into the hook relief space 46, it does not come into contact with the holding member 12 at the hook relief space 46, and therefore the hook portion 30 is not held by the holding member 12. The accommodation recess 38 also has a circular flange receiving portion 48 into which the flange portion 16 of the rotor 8 is fitted to rotatably support it. The bottom surface of the end plate 32 is also formed with a bearing recess 50 that supports the middle portion 70 of the drive shaft 68 (described later). The bearing recess 50 has a circular cross section and is formed away from the accommodation recess 38. A drive side communication hole 52 with a circular cross section is connected to the center of the bearing recess 50, axially penetrating the end plate 32 and rotatably supporting the base end portion of the other side portion 74 of the drive shaft 68 (described later).

In the rotary damper of the present invention, it is important that when the rotating body 8 rotates, the hook portion 28 is relatively pushed by the retaining member 12 in the direction in which the tightening of the spring member 10 is strengthened, and the rotating body 8 slides against the spring member 10. In the illustrated embodiment, the rotating body 8 rotates counterclockwise in the A-A cross section of FIG. 1, so that the hook portion 28 is relatively pushed by the retaining member 12 in the hook groove 44 in the direction in which the tightening of the spring member 10 is strengthened. Here, referring to the material of the rotating body 8, the rotating body 8 is formed of a synthetic resin material having a characteristic that the frictional force between the rotating body 8 and the spring member 10 increases as the rotational speed relative to the spring member 10 increases. Therefore, for example, when the rotating body 8 is connected to the bottom rail of a blind and falls freely in the vertical direction, the rotational speed of the rotating body 8 tries to accelerate under a constant acceleration due to gravity, but as the rotational speed of the rotating body 8 accelerates, the frictional force that the rotating body 8 receives from the spring member 10 increases accordingly, so that the rotational speed of the rotating body 8 is suppressed. Examples of synthetic resin materials having the above characteristics include PPS (polyphenylene sulfide) and PA (polyamide). In order to increase the rigidity of the rotor 8 and improve the speed dependency while suppressing costs, it is preferable to appropriately add glass fiber and calcium carbide to the synthetic resin materials. In the illustrated embodiment, the hook portion 28 extends in the normal direction, so that the entire hook portion 28 is relatively pressed by the holding member 12, thereby preventing the hook portion 28 from bending as much as possible.

In the rotary damper of the present invention, when the rotating body 8 rotates, the hook portion 28 is pushed by the retaining member 12 in a direction that tightens the spring member 10, so the hook portion 28 does not bend excessively due to inertia immediately after the rotating body 8 starts to rotate. Therefore, the rotating body 8 can rotate under the required resistance torque immediately after the start of rotation, that is, without any time delay. In the illustrated embodiment, the number of turns of the wire that forms the spring member 10 is 1, so even if the hook portion 28 is pushed by the retaining member 12 in a direction that tightens the spring member 10 when the rotating body 8 rotates, the rotating body 8 can slide reliably against the spring member 10 without being locked.

Even if the rotating body 8 is made of a material having the above-mentioned characteristics, if the rotary damper 4 is directly connected to the rotating member X without the link mechanism 6, the rotary damper 4 cannot sufficiently suppress the rotation speed of the rotating member X. When the rotating body 8 is connected to the bottom rail of a blind, the bottom rail falls freely in the vertical direction, so a constant rotational torque based on gravity acts on the rotating body 8. However, when the rotating body 8 is connected to the rotating member X, the rotating member X rotates due to gravity, so the magnitude of the rotational torque acting on the rotating body 8 changes depending on the rotation angle position of the rotating member. This will be mentioned further later. Below, the explanation of the link mechanism 6 will continue.

With reference to FIG. 1, the link mechanism 6 includes a one-side link piece 54, an other-side link piece 56, and an intermediate link piece 58. With reference to FIG. 1 and FIG. 5, the one-side link piece 54 has a flat main portion 60. A blocking protrusion 61 protruding outward is provided at a required portion of the side surface of the main portion 60. The main portion 60 further has a cylindrical protrusion 62 formed on one side surface and a connecting hole portion 64 penetrating from one side surface to the other side surface. The cross section of the connecting hole portion 64 is generally circular, but six protrusions 66 extending linearly in the axial direction are formed on the inner peripheral surface at equal angular intervals in the circumferential direction. The one-side link piece 54 is connected to the drive shaft 68 through the connecting hole portion 64. With reference to FIG. 6, the drive shaft 68 is solid and is divided into an intermediate portion 70, a one-side portion 72 located on one axial side of the intermediate portion 70, and an other-side portion 74 located on the other axial side of the intermediate portion 70. The intermediate portion 70 is cylindrical and is disposed in the bearing recess 50 formed in the end plate 32 of the holding member 12, whereby it is supported in a rotatable manner. The one side portion 72 is generally cylindrical and has a smaller diameter than the intermediate portion 70, but has six axially linearly extending protrusions 76 formed at equiangular intervals in the circumferential direction on the outer circumferential surface of its base end. The one side portion 72 is inserted into the connecting hole 64 of the one side link piece 54, and the protrusions 76 engage with the protrusions 66 in the circumferential direction, whereby the one side link piece 54 is connected to the drive shaft 68. The tip of the one side portion 72 on which the protrusions 76 are not formed is supported in a rotatable manner by a circular through hole 78 formed in the shield plate 36. The other side portion 74 is generally cylindrical and has a smaller diameter than the intermediate portion 70, but has six axially linearly extending grooves 80 formed at equiangular intervals in the circumferential direction on the outer circumferential surface of its tip. The base end of the other side portion 74, where the groove 80 is not formed, is inserted into the drive side communication hole 52 formed in the end plate 32 of the holding member 12, and is thereby supported in a rotatable state. The tip end of the other side portion 74 is connected to the rotating member X via the groove 80. As a result, the one-side link piece 54 rotates integrally with the rotating member X around an eccentric axis o2 that is eccentric with respect to the rotation axis o1 of the rotating body 8.

Explaining with reference to FIG. 1 and FIG. 7, the other side link piece 56 has a flat plate-shaped main portion 82. A blocking protrusion 83 protruding outward is provided at a required portion of the side surface of the main portion 82. The main portion 82 further has a cylindrical protrusion 84 formed on one side surface and a connecting hole portion 86 penetrating from one side surface to the other side surface. The cross section of the connecting hole portion 86 is generally circular, but six protrusions 88 extending linearly in the axial direction are formed on the inner peripheral surface at equal angular intervals in the circumferential direction. The other side link piece 56 is connected to the driven shaft 90 through the connecting hole portion 86. Continuing the explanation with reference to FIG. 8, the driven shaft 90 is solid and is divided into an intermediate portion 92, a side portion 94 located on one axial side of the intermediate portion 92, and a side portion 96 located on the other axial side of the intermediate portion 92. The intermediate portion 92 is cylindrical and is inserted inside the rotor 8 of the rotary damper 4. At this time, one axial side of the intermediate portion 92 is disposed in the insertion hole 18 of the rotor 8, and the other axial side is disposed inside the one-way clutch 24. The one side portion 94 is generally cylindrical and has a smaller diameter than the intermediate portion 92, and six axially extending ridges 98 are formed on the outer circumferential surface of the base end portion at equal angular intervals in the circumferential direction. The one side portion 94 is inserted into the connecting hole portion 86 of the other side link piece 56, and the ridges 98 engage with the ridges 88 in the circumferential direction, thereby connecting the other side link piece 56 to the driven shaft 90. The tip end of the one side portion 94 on which the ridges 98 are not formed is rotatably supported by a circular through hole 100 formed in the shield plate 36. The other side portion 96 is cylindrical and has a smaller diameter than the intermediate portion 92, and is inserted into the driven side communicating hole 42 formed in the end plate 32 of the holding member 12, and is rotatably supported by this. As a result, the other side link piece 56 can rotate integrally with the rotating body 8 of the rotary damper 4 around the rotation axis o1.

Explaining with reference to FIG. 1 and FIG. 9, the intermediate link piece 58 is flat, and has a circular one-side hole 102 and other-side hole 104 that penetrate from one side to the other side. The protrusion 62 formed on the one-side link piece 54 fits into the one-side hole 102, and the protrusion 84 formed on the other-side link piece 56 fits into the other-side hole 104. Thus, the one-side link piece 54 and the other-side link piece 56 are connected via the intermediate link piece 58, and these links form a link mechanism. The protrusion 62 and the one-side hole 102 that connect the one-side link piece 54 and the intermediate link piece 58 form the one-side movable joint P1, and the protrusion 84 and the other-side hole 104 that connect the other-side link piece 56 and the intermediate link piece 58 form the other-side movable joint P2.

Next, the operation of combination 2 will be described with reference to FIG. 10 together with FIG. 1. As mentioned above, FIG. 1 shows the state when the swivel member X is in the open position. In the illustrated embodiment, the swivel member X is in the open position when it is raised 80 degrees from the horizontal. When the swivel member X is in the open position, the blocking protrusion 61 provided on the one-side link piece 54 abuts against the inner surface of the outer peripheral wall 34 of the retaining member 12, preventing the one-side link piece 54 from rotating counterclockwise around the eccentric shaft o2 in the CC cross-sectional view of FIG. 1. This prevents the swivel member X from further rotating open from the open position.

Figure 10(a) shows the C-C section when the rotating member X is rotated from the open position by gravity to the closed position and tilted 45 degrees from the horizontal direction as shown in Figure 1. As can be understood by comparing the C-C section of Figure 1 with Figure 10(a), when the rotating member X rotates clockwise in the figure, the one-side link piece 54, which rotates together with the rotating member X via the drive shaft 68, rotates clockwise around the eccentric shaft o2. Then, due to the operation of the link mechanism 6, that is, the one-side link piece 54, the other-side link piece 56, and the intermediate link piece 58, the one-side movable joint P1 approaches the rotation axis o1 while rotating clockwise around the eccentric shaft o2, and the other-side link piece 56 rotates counterclockwise around the rotation axis o1. Since the driven shaft 90 is connected to the other-side link piece 56, the driven shaft 90 also rotates counterclockwise. Here, when the driven shaft 90 rotates counterclockwise, the one-way clutch 24 connects the driven shaft 90 and the rotating body 8 so that they cannot rotate relative to each other, and so the rotating body 8 rotates counterclockwise together with the driven shaft 90 (the direction of rotation of the rotating body 8 is shown by the arrow in the A-A cross-sectional view of Figure 1). As a result, the hook portion 28 of the spring member 10 is pressed relatively in the hook groove 44 of the holding member 12 in a direction that tightens the spring member 10, and a braking torque acts on the rotating body 8.

Here, if the mass of the rotating member X is m, the gravitational acceleration is g, and the rotation angle of the rotating member X with respect to the horizontal direction is θ, then when the rotating member X is rotated closed by gravity, the component force F that the rotating member X receives in the rotation direction due to gravity is mgcosθ. This component force F gradually increases as the rotation angle θ of the rotating member X becomes smaller, that is, as the rotating member X rotates closed toward the closed position. Since torque is proportional to force, the rotation torque when the rotating member X rotates around the eccentric shaft o2 also gradually increases. The component force F and the resulting rotation torque are maximum at the closed position (θ=0°). Therefore, when the rotating member X is directly connected to the rotary damper 4 without the link mechanism 6, even if the braking torque is applied to the rotating body 8 by the spring member 10, it is not sufficient, and the rotation speed of the rotating body 8, i.e., the rotation speed of the rotating member X, cannot be sufficiently suppressed. However, in the illustrated embodiment, the rotary damper 4 is connected to the rotating member X via the link mechanism 6. Therefore, when the rotating member X rotates, the one-side movable joint P1 connecting the one-side link piece 54 and the intermediate link piece 58 approaches the rotation axis o1 while rotating around the eccentric axis o2, causing the other-side link piece 56 to rotate. Since the one-side link piece 54 rotates integrally with the rotating member X, the rotation torque generated by the rotation of the rotating member X is transmitted to the intermediate link piece 58 by the one-side movable joint P1. Moreover, since the one-side movable joint P1 approaches the rotation axis o1, the above rotation torque is reduced accordingly and transmitted to the other-side link piece 56. This is because, as viewed from the other-side link piece 56, the length of the arm from the rotation axis o1, which is the center of rotation, i.e., the distance to the one-side movable joint P1, is gradually reduced. Therefore, even if the rotating member X is rotated from the open position to the closed position by gravity, causing the rotational torque to gradually increase, the link mechanism 6 gradually reduces the rotational torque, so that even the rotary damper 4 described above can sufficiently suppress the rotational speed of the rotating member X.

In the rotary damper of the present invention, when the rotating body 8 rotates, the hook portion 28 is relatively pushed by the retaining member 12 in a direction in which the tightening of the spring member 10 is strengthened, and therefore wear on the outer circumferential surface of the rotating body 8 tends to be accelerated and the service life tends to be shorter than when the hook portion 28 is relatively pushed in a direction in which the tightening of the spring member 10 is weakened (the generated torque is the same because the generated torque comparison is the same). However, since the rotating body 8 rotates only within a predetermined angle range in which the rotating member X rotates, the number of rotations of the rotating body 8 relative to the spring member 10 is reduced compared to when the rotating body 8 rotates continuously in one direction. Therefore, when the rotary damper of the present invention is used as in the illustrated embodiment, the service life of the rotary damper 4 itself is unlikely to be an issue.

When the rotating member X rotates further and is rotated to the closed position (θ = 0°) shown in FIG. 10(b), the blocking protrusion 83 on the other link piece 56 abuts against the inner surface of the outer peripheral wall 34 of the retaining member 12, preventing the other link piece 56 from rotating counterclockwise in FIG. 10(b) about the rotation axis o1. This prevents the rotating member X from rotating beyond the closed position.

When the rotating member X is rotated from the state shown in FIG. 10(b) to the state shown in FIG. 1, that is, when it is rotated from the closed position to the open position, it operates in the opposite direction to the above-mentioned rotating and closing movement. In other words, since the driven shaft 90 is rotated clockwise in FIG. 10(b), the driven shaft 90 rotates freely relative to the one-way clutch 24 (rotating body 8), and the rotating member X can rotate and open without receiving any resistance torque.

The rotary damper and the combination of the rotary damper and the link mechanism constructed according to the present invention have been described in detail above with reference to the attached drawings, but the present invention is not limited to the above-mentioned embodiment, and appropriate modifications and changes are possible within the scope of the present invention. For example, in the illustrated embodiment, the spring member 10 is attached to the outer circumferential surface of the mounting portion 14 of the rotating body 8, but it can also be attached to the inner circumferential surface of the mounting portion. In that case, the hook portion of the spring member is held by a shaft-shaped holding member inserted inside the rotating body, and the one-way clutch is fitted to the outer circumferential surface of the mounting portion. In the illustrated embodiment, the spring member 10 has two hook portions 28 and 30, but the hook portion 30 may be omitted. In addition, the hook portion 28 does not necessarily have to extend in the normal direction, and may be of any shape as long as it is held by the holding member 12.

2: Combination 4: Rotary damper 6: Link mechanism 8: Rotating body 10: Spring member 12: Holding member 14: Mounting part

Claims (10)

The rotating device includes a rotating body having a mounting portion having a circular cross section, a spring member formed by winding a wire in a spiral shape and mounted on the mounting portion of the rotating body, and a fixed holding member,
the spring member has a hook portion, and the hook portion is held by the holding member, so that the spring member cannot rotate with respect to the holding member;
When the rotating body rotates, the hook portion is relatively pressed by the holding member, and the rotating body slides against the spring member,
The rotary damper is formed of a synthetic resin material having a characteristic that a frictional force between the rotating body and the spring member increases as the rotational speed relative to the spring member increases,
A rotary damper, characterized in that, when the rotating body rotates, the hook portion is relatively pressed by the retaining member in a direction in which the tightening of the spring member is increased. The rotary damper according to claim 1, wherein the number of turns of the wire forming the spring member is 1. The rotary damper of claim 1, wherein the hook portion extends in the normal direction. The rotary damper according to claim 1, wherein the spring member is coated with fluorine-based grease. The rotary damper according to claim 1, wherein the spring member is attached to the outer peripheral surface of the mounting portion. The rotary damper according to claim 1, wherein a plurality of the spring members are arranged in the axial direction. The rotary damper of claim 1, wherein the rotating body rotates within a required angular range. The rotary damper according to claim 7, wherein the rotating body is equipped with a one-way clutch. A combination of the rotary damper and the link mechanism according to claim 7 or 8,
the link mechanism includes a one-side link piece that is rotatable about an eccentric shaft that is eccentric with respect to the rotation shaft of the rotating body and rotates integrally with an external device, an other-side link piece that is rotatable about the rotation shaft and rotates integrally with the rotating body, and an intermediate link piece that connects the one-side link piece and the other-side link piece,
When the external device rotates, the one-side movable joint connecting the one-side link piece and the intermediate link piece approaches the rotation axis while rotating around the eccentric shaft, causing the other-side link piece to rotate. 10. The combination according to claim 9, wherein said one-side link piece and said other-side link piece are each formed with a rotation preventing means for abutting against said holding member to prevent rotation of said external device.

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