Damper device

Abstract

To provide a rotary damper using a viscous oil with improved durability. [Solution] The rotary damper includes a housing 2, a rotator 3, a packing, and a packing to prevent oil leakage by sealing viscous oil in the space between the housing 2 and the rotator 3. A Y-shaped packing 16 is applied to the rotating shaft of the rotator 3 to ensure a reliable seal and improve durability.

Description

Technical Field

[0001] The present invention relates to a rotary or pivoting damper device (rotary damper), and more particularly to a packing for preventing viscous oil leakage from a damper and the structure of the edge portion thereof.

Background Art

[0002] Rotary dampers include those with a relatively small diameter as disclosed, for example, in Patent Document 1. Such rotary dampers are used in hinges of opening / closing doors, hinges of table trays, opening / closing hinges of lids, and storage sections of drawers, particularly in locations requiring safety and quality such as slow operation and absorption of impact force, for example, for glass, mirrors, and tableware.

[0003] When the rotary damper used for such a door hinge is disposed at the top and bottom ends of the door, the rotating parts are used to face each other in the vertical direction, so the mounting directions are different, making it necessary to prepare two types of rotary dampers. The same applies to double doors: different upper and lower hinges are required for right-opening and left-opening doors, which is complicated for manufacturers and installers due to the risk of mounting errors, ordering errors, and the like.

[0004] In recent years, consideration has been given to concealing rotary dampers in places visible and touchable by people, such as on furniture and appliances. Furthermore, from the viewpoints of expanding storage space and improving operability, rotary dampers are required to be miniaturized not only for achieving higher precision, higher strength, higher torque, and higher durability, but also from the perspectives of resource saving, production, and logistics cost reduction.

[0005] On the other hand, there is an arrangement in which a packing is used as a means for preventing seal leakage in rotary oil dampers. As one such arrangement, it is known to inject a high-viscosity fluid such as silicone oil between a housing and a rotator, and prevent oil leakage by fitting an O-ring to the seal packing for sealing.

[0006] In the rotary damper disclosed in Patent Document 1, when a packing is used to prevent oil leakage, commercially available JIS standard products (JIS 2401-1:2012, O-rings) exist. Since these O-rings are available in a range of inner diameters starting from 2.8 mm, they are widely used as packings for small-diameter oil dampers.

[0007] Furthermore, sealing devices (seals) used to prevent oil leaks, etc., are classified into moving seals (packings) and static seals (gaskets). Moving seals (packings) are further classified into rotating shaft seals and reciprocating seals (rod seals, piston seals). Rotating shaft seals are further classified into contact seals and non-contact seals. Contact seals include oil seals, mechanical seals, and gland packings. On the other hand, reciprocating seals (rod seals, piston seals) include lip packings and squeeze packings. Lip packings include U-packings, V-packings, Y-type packings, L-packings, etc. Squeeze packings include O-rings, X-rings, D-rings, etc.

[0008] Since the rotary damper disclosed in Patent Document 1 involves rotational motion, it is preferable to use an oil seal, which is a contact-type seal for the rotating shaft seal. On the other hand, commercially available JIS standard oil seals (JIS2402 oil seals) have a minimum nominal inner diameter of 7mm and an outer diameter of 18mm, which are quite large.

[0009] Here, we will explain why it is not possible to further miniaturize the oil seal itself. Figure 6 is a cross-sectional view showing a typical ring-shaped JIS standard oil seal, where Figure 6(A) shows the oil seal alone and Figure 6(B) shows the assembled and installed state.

[0010] In the figure, the oil seal 8 has a metal ring 9 integrally formed inside an NBR (rubber material), with a fitting portion 8a formed on the circular outer surface. The end of the metal ring extends to the nose 8b, ensuring that it does not deform even when lightly press-fitted. Furthermore, the metal ring 9 extends in the inner diameter direction to form a back face 8f, which allows it to abut against the mating surface (not shown) for positioning and support during assembly.

[0011] A dust lip 8e is provided on the inner diameter side of the back face 8f. Additionally, a lip tip 8d is provided on the inner diameter side of the seal lip 8c. A spring 10 is attached to the seal lip 8c, applying a biasing force to the lip tip 8d in the inner diameter direction.

[0012] Figure 7(A) is a schematic diagram of the O-ring 17 when it is installed on a rotating part, in which the O-ring 17 is sealed between the guide 26 and the sliding surface 19 with a deformation deflection of approximately 20% to 30%. The outside of the O-ring forms an outer nip surface 20 and an inner nip surface 21. At this time, the rubber reaction force and load distribution of the O-ring are as shown in the nip pressure distribution 22, and it is supported by surface pressure.

[0013] Figure 7(B) is a schematic diagram showing the lip tip 8d of the oil seal 8 shown in Figure 6. When the lip tip of the oil seal lip 23, which consists of an inner side surface 23a and an outer diameter side surface 23b, is biased against the rotating sliding surface 19, a nip surface 24 is formed in a narrow area. Since the nip surface 24 is pressurized for cleaning in a narrow area, the surface pressure increases, making it possible to obtain a strong tightening force as shown in the nip pressure distribution 25. In addition, since the contact surface is small, the effect of frictional resistance is reduced, making it suitable for rotating shafts.

[0014] Figure 6(A) shows the oil seal 8 assembled, with the mating portion 8a being held and fixed to the inner diameter of the retainer 11 by light press-fitting. The rotating shaft 12S is in contact with the dust lip 8e, preventing dust from entering from the outside air section 13. The tip of the lip 8d is in contact with the rotating shaft 12 by the biasing force of the outer surface and the spring 10, forming a nip portion 14 of a predetermined length. The tensioning force created by the biasing force provides a seal between the lip and the rotating shaft 12. This prevents oil leakage from the oil chamber 15.

[0015] Thus, the oil seal includes a metal ring 9 and a spring 10, and is structurally complex in order to satisfy the necessary functions of a robust oil seal. Therefore, miniaturization to the extent that it can replace the oil seal has not been achieved, and there is no lineup of small diameters in terms of dimensions. However, in order to further reduce the outer diameter of the rotary damper, it had become common practice to use an O-ring in the rotating seal section.

[0016] On the other hand, it is necessary to consider the conditions for using O-rings. There is a regulation on the amount of compression the O-ring must undergo when it is installed in the sealing area, and if it is not compressed by a certain amount, it will leak and the sealing force cannot be obtained. The compression reaction force of the nip portion, which is the amount of compression of the rubber material of the O-ring, becomes the resistance force to the rotation of the sealing area. As a result, the frictional force adds a load to the damper's rotational torque, which is the original damper performance using a kinematic viscous fluid, and there is a problem that this reduces the smooth damping characteristics of the basic performance and has an adverse effect.

[0017] Furthermore, during prolonged use, the O-ring rubber at the nip section wears down and deteriorates. This wear and deterioration leads to a decrease in torque, which is a variable factor. As durability continues to advance, the compression set elasticity decreases due to the aging of the rubber, leading to problems such as oil leakage. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] Japanese Unexamined Patent Publication No. 7-158665 [Overview of the project] [Problems that the invention aims to solve]

[0019] The problem to be solved in this invention is to ensure stability of rotational torque in a confined space and durability by improving sealing performance, while maintaining the rotational torque of a rotary damper and making it slimmer in diameter. Specifically, the objective is to reduce the resistance force of conventional packing while performing degassing due to the high kinematic viscosity of viscous fluids, air removal when installing packing, and maintaining the sealing force of the packing.

[0020] For example, O-rings made of NBR (Acrylonitrile Butadiene Rubber) are known to shrink and harden by about 3-7% when immersed in silicone oil in a high-temperature environment (100°C). If used for a long period of time at relatively high temperatures, not only will there be permanent deformation due to the applied pressure and wear due to durable rotation, but the properties of the rubber may also change, potentially leading to accelerated wear and a decrease in sealing performance. Other commonly known problems include decreased sealing performance due to "twisting" during installation, "galling" caused by being pressed into a gap, "tearing" where the O-ring is cut off only to the extent of its compression, "protrusion" where part of it becomes curved, and furthermore, "ozone degradation" due to aging, and "peeling" where the sliding surface peels off in a scale-like pattern.

[0021] On the other hand, using an oil seal provides excellent sealing performance for rotating parts because the lip portion is flexible. However, conventional oil seals for rotating shafts have a complex internal structure, resulting in an outer hole size that is larger than the inner diameter of the shaft they can be installed on. Consequently, small oil dampers using O-rings lack sufficient durability, leading to oil leakage from the damper's seal. Therefore, there has been a demand from the market and customers for highly durable rotary dampers.

[0022] The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a rotary damper for a hinge that achieves size reduction while dramatically improving durability and ensuring sealing performance by minimizing torque fluctuation after long-term use with respect to damper torque. [Means for Solving the Problems]

[0023] In order to achieve the above object, the present invention provides a rotary damper comprising: a cylinder having a closed end; and a columnar rotating rotator mounted with a gap between the cylinder and an inner wall of the cylinder, the rotator having an anti-rotation mounting shape on a shaft portion protruding outward from an opening end of the cylinder, wherein a packing for sealing viscous oil filled in the gap between the cylinder and the rotator is provided, the packing is ring-shaped and has a Y-shaped cross-sectional shape including an inner lip portion and an outer lip portion, one end of the inner diameter side lip portion seals between the shaft portion, one end of the outer diameter side lip portion seals the gap between the packing and the cylinder, and a holding surface that auxiliary supports a radially inner side surface, an outer side surface, or either of them is provided near a rear end portion of the packing. [Effect of the Invention]

[0024] In the present invention, by using a Y-shaped packing or U-shaped packing conventionally used for reciprocating motion, and providing a receiving surface for preventing the packing from falling near the support portion of the Y-shaped packing to stabilize the position and angle of the nip, which is the sliding position of the lips on the inner and outer peripheral surfaces, sealing performance equivalent to that of an oil seal can be ensured despite the small diameter. [Brief Description of the Drawings]

[0025] [Figure 1] It is a perspective view showing the external shape of a rotary damper, (A) is a perspective view showing the first embodiment, and (B) is a diagram showing a conventional configuration. [Figure 2] It shows the rotary damper shown in Fig. 1 (A), where (A) is a front view, (B) is a left side view, (C) is a cross-sectional view taken along line A-A of Fig. (A), and (D) is a cross-sectional view taken along line B-B of Fig. (A). [Figure 3] Figure 1(A) shows the rotary damper in a disassembled state, with (A) being an external view and (B) being a cross-sectional view along line CC in Figure (A). [Figure 4] Figure 1(A) is a perspective view showing the rotary damper in a disassembled state. [Figure 5] This figure shows another example of a rotary damper configuration, where (A) is a front view, (B) is a cross-sectional view along line DD in figure (A), and (C) is a cross-sectional view along line EE in figure (A). [Figure 6] This diagram shows a conventional oil seal used in the rotational direction, with (A) being a cross-sectional view and (B) being a cross-sectional view in use. [Figure 7] (A) and (b) are schematic cross-sectional diagrams illustrating the characteristics of the nip pressure distribution of the packing. [Figure 8] (A) is an exploded perspective view showing a second embodiment of the rotary damper, and (B) is a diagram showing the packing configuration. [Figure 9] (A) is a cross-sectional view of a damper with a Y-shaped packing for the piston rod, and (B) is an enlarged view of the main part. [Figure 10] This is a cross-sectional view of a rotary damper that uses a Y-shaped packing for both the piston and rod in a pneumatic system. [Figure 11] Figure 10 is a magnified view of a rotary damper with the Y-shaped packing installed in the packing mounting groove. [Figure 12] Figure 11 is a magnified view of a rotary damper showing the Y-shaped packing in a tilted state. [Figure 13] Figure 10 is a magnified view of a rotary damper with a support surface provided on the Y-shaped packing. [Figure 14] (A) is a diagram showing the configuration of a Y-shaped packing, and (B) is a partial cross-sectional view showing the Y-shaped packing for the piston rod assembled into a rotary damper. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the drawings. The rotary damper of this embodiment comprises a housing, a rotator, a packing, and viscous oil sealed in the space between the housing and the rotator. The packing to prevent oil leakage is a Y-shaped packing. A Y-shaped packing is applied to the rotating shaft (a U-shaped packing may also be used) as a sealing means to reliably achieve sealing performance and improve durability. In other words, by sealing the inside of the oil damper with viscous oil and increasing the packing pressure on the inner and outer wall surfaces, improved sealing performance, improved durability, and improved ease of assembly are achieved.

[0027] [First Embodiment] Figures 1 to 5 are explanatory diagrams of the first embodiment of the present invention. In the perspective view of Figure 1(A), the rotary damper 1 is assembled from a cylindrical housing (a cylinder with closed ends) 2, a rotator 3 protruding from inside the housing 2, and a cap 4 that holds and guides the rotator 3 (Figure 1(B) is a perspective view of a conventional rotary damper).

[0028] The rotary damper 1 is molded by resin molding. The housing 2 has a flange 2c that extends in a roughly rectangular shape from the side, and is provided with through holes 2a and 2b, where screws can be attached to the hinges of furniture or doors. Since the rotary damper 1 is a resin part, it has a reinforcing rib shape 2d while also being hollowed out to reinforce the holes and remaining surface.

[0029] Figure 1(B) is a perspective view showing a typical rotary damper for a conventional hinge. In this figure, the flange 2p extending from the housing 2 extends in a plate-like manner from the lower side of the center of the rotator 3. Through holes 2n and 2r for screw fastening are provided here, and triangular ribs 2k and 2m are provided to prevent damage to the flange when it is attached to a door or the like for opening and closing. Therefore, even if one attempts to screw it in the upper direction, the flange position will be different, and furthermore, the triangular ribs 2k and 2m will get in the way, resulting in the problem that they cannot be placed at the same center position when used as a set of upper and lower hinges for the same door.

[0030] The housing 2 and rotator 3 shown in Figures 1(A) and 2 are cylindrical and share the same center, and the flange 2c forms parallel planes S1 and S2 from the center line 2j, as shown in the BB cross section. S1 and S2 are of the same dimensions with a central distribution, and the through holes 2a and 2b in the front view can be screwed in from either direction on either side. As described above, in this embodiment, since the flange is symmetrical, only one type of rotary damper 1 for the hinge is sufficient, without having to worry about the mounting orientation.

[0031] The internal structure of the rotary damper will be explained using the cross-sectional view in Figure 2(C), as well as Figures 3 and 4. The housing 2 is cylindrical with one side being bag-shaped and the other side open, and a cylindrical housing shaft 2e is provided in the center of the inside. A cylindrical rib 2f is provided around it, all centered. Near the opening, a circular stepped guide sliding surface 2i is provided to allow the rotator 3 to slide and rotate.

[0032] The rotator 3 has a cylindrical portion 3b and a shaft portion 3e extending from the guide rib 3k, and is sized to form a narrow gap necessary for the damper between them and the cylindrical rib 2f inside the housing 2. It is positioned by fitting and sliding with the housing shaft 2e. As shown in Figures 4 and 5, the cylindrical portion 3b has a passage 3d for viscous oil and an oil reservoir outer groove 3g on the outer circumferential surface opposite the inner diameter of the housing. An oil reservoir inner groove 3h is also provided on the inner circumferential surface of the cylindrical portion 3b. When the rotator 3 rotates, the high-viscosity oil sealed inside accumulates in this reservoir and then flows back into the narrow surface. In other words, it acts as a scraper for the high-viscosity oil, ensuring that a uniform amount of high-viscosity oil is supplied uniformly over a wide area. This creates a labyrinth configuration, and by adjusting the kinematic viscosity and surface area of ​​the oil, it is possible to provide a damper with high torque and high drag even if the outer diameter of the housing 2 is reduced.

[0033] Similarly, as shown in Figure 5, high-viscosity oil (viscous oil 6) is injected into the gap 7a between the housing 2 and the cylindrical portion 3b of the rotator 3, the gap 7b between the cylindrical rib 2f and the shaft portion of the rotator 3, the gap 7c between the edge of the cylindrical rib 2f and the base end edge of the shaft portion of the rotator 3, the gap 7d between the bottom surface of the cylindrical rib 2f and the tip end edge of the shaft portion of the rotator 3, and the gap 7e between the outer circumferential surface of the cylindrical rib 2f and the inner surface of the shaft portion of the rotator 3. This viscous oil 6 is, for example, silicone oil, i.e., an organosilicon compound polymer (synthetic polymer) with a basic framework of siloxane bonds (-Si-O-) in which silicon (Si) and oxygen (O) are alternately linked, and is composed of a liquid substance with a chain-like polymer structure. This silicone oil has a kinematic viscosity of 100,000 CS to 1,000,000 CS (centistokes), and generates a damper force through the shear force of the oil and Couette flow.

[0034] An annularly recessed packing mounting groove 3m is formed on the outer circumferential surface of the rotator 3, and guide ribs 3c and 3k are provided coaxially on both sides thereof. An elastic rubber packing 5, specifically a ring-shaped rubber packing with a rubber hardness of 60 to 80 degrees (durometer type Shore A), is fitted into this packing mounting groove 3m to seal and prevent leakage of the viscous oil sealed inside.

[0035] Furthermore, a rotating shaft 3n is provided coaxially from the guide rib 3c, and two-sided beveled surfaces 3i and 3j are arranged to form parallel surfaces with their center distribution, so that it is fitted into the rotating body (not shown) and rotates. A weight-reducing cutout 3a is provided at the center of the rotating shaft 3n as needed. As for the ring-shaped rubber packing 5, it is preferable to use a Y-shaped packing (U-packing) as will be described later.

[0036] The cap 4 is fitted onto the rotating shaft 3n and is rotatable. The outer circumference can be pressed into place up to the abutment portion 4b using the rotator 3 and snap-fit, and can also be integrally formed by means of ultrasonic welding (ultrasonic welder) or adhesive to maintain airtightness. Furthermore, in the rotary damper described above, conventional users had to prepare two types of asymmetrical flange hinges, but by making the flange shape symmetrical and attachable from both sides, there is an advantage in preventing incorrect assembly.

[0037] [Second Example] Figures 8(A)(B) and 9(A)(B) show a second embodiment. In this embodiment as well, the flange 2c formed on the housing 2 is configured in the same way as in the first embodiment.

[0038] In the figure, a ventilation slot 2s is provided on the inner diameter guide sliding surface 2i of the opening of the plastic housing 2, which has sliding properties and an integrally molded flange 2c. The inner side of this ventilation slot 2s is provided with a slope 2t such that the groove gradually becomes shallower. The packing 5 fitted into the packing mounting groove 3m of the rotator 3 has a Y-shaped cross-sectional structure with an outer lip portion 5b and an inner lip portion 5c. Therefore, when inserting and assembling the packing 5, the outer lip portion 5b does not get caught but is naturally pushed back to reach the surface of the guide sliding surface 2i and conform to the same plane. Furthermore, when attaching the rotator 3 to the housing 2, the rotator 3 is inserted up to the abutment step 2w, and the locking claw 2x of the housing 2 is further engaged with the rotating rib 3u, and the assembly is completed when it rotates while preventing it from coming loose.

[0039] Similarly, the ventilation opening 9m is also provided on the outer surface of the rotator's rotating rib 3u. Air inside the housing passes through holes in the passage 3d formed on the shaft of the rotator 3, through the gaps in the guide rib 3k, and reaches the packing mounting groove 3m. In this case, when the outer lip portion 5b is positioned near the ventilation slot 2s during insertion, air escapes from the ventilation slot 2s and is discharged to the outside through the ventilation opening 9m. Subsequently, as the rotator 3 is further inserted, the outer lip portion 5b passes over the slope 2t. This increases airtightness and raises the internal pressure containing the viscous oil. Consequently, the oil seal is pressed against the end face side 5a by this reaction force, and the inner lip portion 5c and outer lip portion 5b are pushed apart, increasing the pressure on the guide sliding surface 2i and packing mounting groove 3m with greater force, thereby improving the sealing performance. At the same time, because it is made of elastic rubber, the packing 5 is pushed out towards the end face side 5a and expands.

[0040] To concentrate the pressurizing force on the lip, a sloped relief 3t is provided in the packing mounting groove 3m of the rotator 3, allowing for some leeway even if the rubber lip expands. In other words, it is common knowledge that Y-shaped packings, which are originally used in reciprocating motions such as pistons, cannot be used in the rotational direction. This is because it is not possible to apply an appropriate biasing force to the lip, and the packing tends to collapse. In this embodiment, this point is taken into consideration, and a support surface 3r is provided to support the inner surface of the base end of the packing 5 to prevent the packing 5 from collapsing. Furthermore, by using a ventilation slot 2s to stop the air venting midway and then applying pressure, the internal pressure of the lip is increased using Pascal's principle, increasing the biasing force and enhancing the sealing force, making it possible to install a Y-shaped packing even in the rotational direction.

[0041] On the other hand, in this embodiment, in order to reduce the number of parts, the same effect is achieved without using the cap 4. As described above, a locking claw 2x is provided at the opening of the housing 2. By providing this locking claw 2x, the inner undercut portion that cannot be removed with the molding die of a normal resin mold cavity and core can be molded with an inner slide mold configuration.

[0042] Furthermore, in order to reduce the load on the locking claws 2x and allow for smooth rotation, it is necessary to suppress the tilting of the rotator 3. In this embodiment, a guide sliding groove 2u is provided near the tip of the cylindrical portion 3b, or a guide sliding surface 2i is provided to prevent wobbling by making it an intermediate fitting sliding surface, so as to prevent the claws from coming off or being damaged due to a large load being applied to the rotation axis 3n of the rotator 3.

[0043] In this way, not only is the outer diameter of the housing 2 reduced, but the surface area of ​​the viscous oil filling section is also increased, making it possible to select a lower viscosity, easier-to-handle viscous oil. Furthermore, by adopting the Y-shaped packing 5, it is possible to make the rotary damper smaller while also providing high durability.

[0044] [Third Embodiment] Figures 10 and 11 illustrate a third embodiment. Figure 10 is a cross-sectional view showing an example of a rotary damper configuration using a more flexible packing (Y-shaped packing) that can be used for both the pneumatic piston and rod. Figure 11 is a partially enlarged view of the rotary damper with the Y-shaped packing shown in Figure 10 installed in the packing mounting groove.

[0045] The Y-shaped packing 16, which is more flexible and has a larger deflection range and can be used for both the piston and rod of a pneumatic system, has a longer distance from the branching point 16b to the lip portion, outer lip portion 16c, and inner lip portion 16d. This allows it to function as an accumulator, better absorbing volume changes due to temperature changes in the oil chamber 15. As a result, fluctuations in the biasing force applied to the nip portion are easily suppressed. Consequently, a rotary damper with less variation in damper force can be provided.

[0046] Figures 10 and 11 show the state in which the Y-shaped packing 16 is installed in the packing mounting groove 3m of the rotator 3, the housing 2 is mounted, and the cap 4 is press-fitted and fixed in place. The Y-shaped packing 16 has a body 16a that branches into two at a branching point 16b, forming an outer lip portion 16c and an inner lip portion 16d. The body 16a is a ring-shaped rubber packing consisting of an inner surface 16e, an outer surface 16f, and a back face 16g. This Y-shaped packing 16 is housed in the packing mounting groove 3m of the rotator 3.

[0047] Figure 12 is a cross-sectional view showing the Y-shaped packing 16 tilted at an angle during actual use of the rotary damper 1. When the rotator 3 rotates or turns repeatedly with the Y-shaped packing 16 installed, the outer lip portion 16c and inner lip portion 16d of the Y-shaped packing 16 are subjected to pressure from the viscous oil sealed inside the oil chamber 15 inside the housing 2, at the sliding surface of the packing mounting groove 3m and the inner circumferential surface of the cap 4. Due to the effects of changes in the pressing pressure, frictional force, and dynamic frictional force of these lip portions, it becomes impossible to maintain the same nip position on the circumference, and a portion of the edge region 13b, near the inner lip portion 16d, begins to shift significantly laterally, as shown in the figure. This phenomenon is one reason why Y-shaped packings are generally unsuitable and cannot be selected as sealing packings in the rotational direction.

[0048] In other words, as shown in Figure 12, once the seal is tilted, it is difficult for it to return to its original position on its own, and as a result, the oil inside seeps out from the outer circumference (nip) of the rotation axis 3n of the rotator 3 of the rotary damper 1. Therefore, if this rotary damper is applied to wooden furniture, the seeping silicone oil has high permeability and will spread into the wood of the furniture, causing wet-looking stains to spread, which is undesirable. For this reason, measures are needed to prevent oil leakage even during high-durability testing.

[0049] In this embodiment, as shown in Figure 13, the rear end of the Y-shaped packing 16 shown in Figure 10 is supported by auxiliary support surfaces (holding surfaces) 4c and 3r, addressing the problems that arise in Figure 12. With the packing holding configuration shown in Figure 13, the packing is stably fixed like an oil seal, and measures are taken to ensure that the lip does not shift position or fall over, and instead traces a constant trajectory around the circumference. The following will explain its structure in detail.

[0050] It was found that when the inner surface 16e and outer surface 16f (see Figure 12), which are the sides of the body 16a of the Y-shaped packing 16, are held, the position of the branch portion 16b is located approximately in the center, and its movement is restricted. As a result, the Y-shaped packing 16 is supported at three points: the outer lip portion 16c, the inner lip portion 16d, and the branch portion 16b. This reduces lateral movement in the longitudinal direction of the axis, enabling a stable seal through the sliding of the ribs.

[0051] As a method of supporting the body 16a described above, a support surface (holding surface) 3r is provided in the packing mounting groove 3m of the rotator 3, and a slope 3s is provided at the stepped portion. The inner surface 16e of the Y-shaped packing 16 is in contact with this surface.

[0052] On the other hand, the inner diameter sliding surface 4a of the cap 4 is provided with a support surface (holding surface) 4c and an inclined surface 4d, so that the outer surface 16f of the body comes into contact with them. Each contact surface is not clamped with strong force, but is assembled with so-called intermediate fitting dimensions so as not to affect rotational sliding. Therefore, it is possible to prevent lateral displacement of the nip position. As a result, even if the nip of the oil seal is long, it is possible to seal the pressure from the oil chamber 15 and increase the amount of nip deflection. In other words, it has the effect of suppressing the expansion of the nip width due to wear for a long period of time, and a configuration that minimizes wear and pressure changes has been achieved, so that sealing performance can be maintained for a long period of time even in high-durability rotation, which contributes to extending the life of the oil damper.

[0053] The support surfaces described above may be provided on both the radially inner and outer surfaces of the Y-shaped packing, or on only one side.

[0054] Figure 14 is an explanatory diagram showing the application of a shallow groove Y-shaped packing 18 for the piston rod to a rotary damper 1, where (A) is a diagram showing the configuration of the Y-shaped packing, and (B) is a partial cross-sectional view showing the Y-shaped packing for the piston rod assembled into the rotary damper. The shallow groove Y-shaped packing 18, with a Y-shaped cross-section as shown in Figure 14(A), is suitable for reciprocating motion around a circular shaft, and the rigidity of the packing is increased by increasing the distance from the body 18a to the branching portion 18b.

[0055] The inner lip portion 18d extending inward from the branched portion 18b and the outer lip portion 18c extending outward form an edge, but the length of the inner lip portion 18d is short, and the tip shape of the inner lip portion 18d is mountain-shaped to ensure reliable sealing during reciprocating motion in the longitudinal direction of the axis. In addition, one side of the outer lip portion 18c has a surface that is substantially parallel to the body back face 18e, and the lip tip has an edge shape. This suppresses fluttering when fixed and ensures sealing performance.

[0056] Furthermore, as shown in Figure 14(B), in this embodiment, measures have been taken to ensure that the O-ring can be used to compensate for the shortcomings of the O-ring despite its small size. In the same figure, the rotary damper 1 is designed to handle high torque and high rotational speeds. When the oil chamber 15 is filled with silicone oil ranging from a kinematic viscosity of 500,000 CS (centistokes) to its maximum kinematic viscosity of 1,000,000 CS, and the rotational speed is increased to approximately 400 rpm compared to the usual 20 rpm, the pressure caused by the shear force of the silicone oil, which is sealed within the oil chamber, is applied to the shallow groove Y-shaped packing 18.

[0057] To withstand this, the shallow groove Y-shaped packing 18 also needs to be strong. The inner side, where the body 18a is large and the lip portion beyond the branching part 18b is small, has a higher pressure resistance because the amount of deflection of the rubber material is suppressed. As the body is longer than the support surfaces 4c and 3r shown in Figure 13, it can support a larger area, so the expansion of the rubber due to pressure can be supported over a wider area.

[0058] As described above, since the Y-shaped packings 16 and 18 can be selected and used according to the application, the rotary damper, despite its small diameter and compact size, has exceeded the durability performance of conventional products, allowing for a wide range of applications and compatibility with various uses. Furthermore, when the rotator with the packing attached is mounted to the housing, the groove, which serves as a ventilation passage, is extended to a position just before the mounting position. Then, as it is inserted to the predetermined position while being sealed by the packing, the inside is compressed, and a biasing force acts in the direction that expands the lip portion of the packing. This increases the sealing force and achieves sealing performance equivalent to that of the spring in the lip portion of an oil seal.

[0059] [Industrial applicability] The rotary damper according to the present invention is applicable to hinges on furniture doors and bathroom mirror doors, but can also be widely used in other applications besides furniture, such as kitchen drawers, folding tables on trains and airplanes, car console lids, audio equipment, and washing machine lids. [Explanation of symbols]

[0060] 1 Rotary damper 2 Housing 3 Rotators 3r support surface 4 caps 4c support side 5. Packing 6. Viscous oil 7a~7e Oil injection gap 8 Oil seals 9 Metal ring 10 springs 11 Holding body 12 Rotation axes 13. Outdoor air section 15 Oil chamber 16 Y-shaped packing 17 O-rings 18 Shallow groove Y-shaped packing 26 Guide

Claims

1. A rotary damper comprising a cylinder with a closed end, a cylindrical rotating rotator fitted with a gap between it and the inner wall of the cylinder, and having a rotation-stopping mounting shape on the shaft portion that protrudes outward from the open end of the cylinder, wherein a packing is provided to seal the viscous oil filled in the gap between the cylinder and the rotator, The packing is ring-shaped and has a Y-shaped or U-shaped cross-section comprising an inner lip portion and an outer lip portion. One end of the inner diameter lip portion seals the gap between it and the shaft portion, and the other end of the outer diameter lip portion seals the gap with the cylinder. A rotary damper characterized in that a retaining surface is provided near the rear end of the packing to auxiliaryly support the radial inner surface and the outer surface, or either of them.

2. The rotary damper according to claim 1, characterized in that, on the inner surface of the cylinder or the outer surface of the rotator, one or more air vent grooves are provided around the circumference near the lip portion of the packing that abuts against each other, and the mounting end has a groove that extends to a position just before the lip contact sliding region, and when the ring-shaped packing mounted on the rotator and outer surface is pressed in, the internal pressure rises from the position where the groove portion is interrupted, and that amount is converted into applied pressure on the lip portion of the Y-shaped packing, causing the sealing pressure to rise above atmospheric pressure and pressing the lip strongly against the circumferential sliding surface.

3. The rotary damper according to claim 1 or 2, characterized in that a retaining flange extending and protruding from the side surface of the housing has a seating surface that is substantially parallel to the center of the rotation axis at an equal distance from the center of the rotation axis, and the seating surface is provided with a substantially circular through hole that is provided in a direction perpendicular to the seating surface.

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