Damper device

Abstract

Provided is a damper device that can reduce a piston operation force when the piston is moving in a return direction opposite the damper braking direction. This damper device 10 is provided with a cylinder 20, a rod 30, a piston 40 with an annular groove 50, and a sealing ring 60, wherein: in the bottom portion of the annular groove 50, a deep bottom portion 51 and a shallow bottom portion 52 are provided; the sealing ring 60 has an outer peripheral surface provided with a cylinder contact portion that makes contact with the inner peripheral surface of the cylinder 20 and an inner peripheral surface provided with a shallow bottom portion contact portion that makes contact with the shallow bottom portion 52; the center of the cylinder contact portion and the center of the shallow bottom portion contact portion are shifted in the axial direction; and when the piston 40 moves in the damper braking direction F1, the inner peripheral surface of the sealing ring 60 does not contact the deep bottom portion 51.

Description

Technical Field

[0001] The present invention relates to a damper device used for braking, such as the opening and closing operation of a glove box in an automobile.

Background Art

[0002] For example, a damper device may be used in a glove box of an automobile to suppress the sudden opening of the lid and cause it to open gently.

[0003] As such a damper device, Patent Document 1 below describes an air damper having a cylinder member, a piston member movably provided inside the cylinder member and having an air passage, a seal member disposed in a recess formed on the outer periphery of the piston member for sealing the inner peripheral surface of the piston member and the cylinder member, a rod member, a pushing portion provided on the rod member for moving the piston member when the rod member is pushed into the bottom plate of the cylinder member, and a suction cup member for opening and closing the air passage. The seal member is an O-ring having a circular cross-section, and the seal member is adapted to contact the inner peripheral surface of the cylinder member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of the air damper of Patent Document 1 above, since the seal member is an O-ring, when the piston moves in the return direction in which the braking force of the damper does not act, the frictional resistance of the seal member against the inner peripheral surface of the cylinder member is high, and it is difficult to reduce the operating force of the piston.

[0006] Accordingly, an object of the present invention is to provide a damper device capable of reducing the operating force of a piston when the piston moves in a return direction opposite to the damper braking direction.

Means for Solving the Problems

[0007] To achieve the above object, the present invention is a damper device attached between a pair of members approaching and separating from each other, and applying a braking force when the pair of members approach or separate, comprising a cylinder having an opening at one end, a rod movably inserted into the cylinder through the opening, a piston connected to the rod and having an annular groove formed on the outer periphery, and a seal ring attached to the annular groove and pressed against the inner peripheral surface of the cylinder. At the bottom of the annular groove, a deep bottom portion disposed on the damper braking direction side and a shallow bottom portion disposed on the side opposite to the damper braking direction and having a shallower bottom than the deep bottom portion are provided. The seal ring is provided with a cylinder contact portion on the outer peripheral surface that contacts the inner peripheral surface of the cylinder and a shallow bottom contact portion on the inner peripheral surface that contacts the shallow bottom portion. The center of the cylinder contact portion and the center of the shallow bottom contact portion are displaced in the axial direction, and the inner peripheral surface of the seal ring is configured not to contact the deep bottom portion when the piston moves in the damper braking direction.

Effects of the Invention

[0008] In the present invention, when the piston moves in the return direction opposite to the damper braking direction, the seal ring deforms toward the deep bottom portion side of the annular groove due to the frictional force from the inner peripheral surface of the cylinder acting on the cylinder contact portion with the shallow bottom contact portion contacting the shallow bottom portion as a fulcrum. As a result, the pressing force of the cylinder contact portion against the inner peripheral surface of the cylinder decreases, so that the frictional resistance between the inner peripheral surface of the cylinder and the cylinder contact portion can be reduced, and the operating force of the piston when the piston moves in the return direction can be reduced.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying out the Invention

[0010] (One Embodiment of the Damper Device) Hereinafter, with reference to the drawings, one embodiment of the damper device according to the present invention will be described.

[0011] The damper device 10 shown in FIG. 1 is attached to a pair of members that approach and separate from each other, and applies a braking force when the pair of members approach or separate. For example, it can be used for braking, such as a glove box or a lid that is openably attached to an opening of a storage portion provided in an instrument panel of an automobile. In the following embodiments, one member will be described as a fixed body such as a storage portion of an instrument panel, and the other member will be described as an opening / closing body such as a glove box or a lid that is openably attached to an opening of the fixed body.

[0012] As shown in FIG. 1, the damper device 10 of this embodiment mainly includes a cylinder 20 provided with an opening 23 at one end, a rod 30 movably inserted into the cylinder 20, a piston 40 connected to the rod 30 and having an annular groove 50 formed on the outer periphery, a seal ring 60 attached to the annular groove 50 of the piston 40, a seal cap 70 attached to the other end side of the cylinder 20, and a detachment prevention cap 80 attached to the opening 23 on the one end side of the cylinder 20. Further, as shown in FIG. 8, when the piston 40 is inserted into the cylinder 20, the seal ring 60 is pressed against the inner peripheral surface of the cylinder 20. With this seal ring 60 as a boundary, a first chamber R1 (air chamber) is formed on the insertion direction side of the rod 30 in the cylinder 20, and a second chamber R2 is formed on the opening 23 side of the cylinder 20.

[0013] In the following description, the "one end portion" or "one end" means one end portion or one end on the damper braking direction side of the damper device 10, and the "other end portion" or "other end" means the other end portion or the other end on the return direction side opposite to the damper braking direction. Further, the "damper braking direction" in this embodiment means the direction in which the piston 40 moves away from the end wall 25 (see FIG. 8) of the cylinder 20 and the drawing amount of the rod 30 from the opening 23 of the cylinder 20 increases (see the arrow F1 in FIG. 8). Furthermore, the "return direction opposite to the damper braking direction" (hereinafter, also simply referred to as the "damper return direction") in this embodiment means the direction in which the piston 40 approaches the end wall 25 of the cylinder 20 and the pushing amount of the rod 30 into the cylinder 20 increases (see the arrow F2 in FIG. 8).

[0014] As shown in FIG. 1, the cylinder 20 has a substantially cylindrical wall portion 21 extending in a predetermined length, and one end portion side in the axial direction is open and an opening 23 is provided. At the periphery of this opening 23, at positions facing each other in the radial direction, a pair of locking holes 23a, 23a are formed. Further, as shown in FIG. 8, an end wall 25 is disposed at the other end portion of the wall portion 21 (it can also be said that the end wall 25 is disposed on the side opposite to the opening 23 of the wall portion 21), and a through hole (not shown) is formed in this end wall 25. Further, a cap mounting wall 25a projects from the outer surface of the end wall 25, and a seal cap 70 is mounted on the cap mounting wall 25a.

[0015] This seal cap 70 is formed of an elastic resin material such as rubber or elastomer, and is attached to the cap mounting wall 25a. An orifice 71 is formed to penetrate a predetermined portion of this seal cap 70 (see FIG. 8). And when the damper is braked, the seal cap 70 abuts against the periphery of a through hole (not shown) in the end wall 25 of the cylinder 20 to seal the first chamber R1 of the cylinder 20, and when the damper braking force is released, it separates from the periphery of the through hole (not shown) to enable the air in the first chamber R1 of the cylinder 20 to be exhausted. Note that the damper braking force is adjusted by the flow resistance of the air passing through the orifice 71.

[0016] Also, on the outer periphery of the wall portion 21 and at both axial ends, rotation support pieces 27 forming rotation holes 27a project respectively. A rotation shaft (not shown) of one of the aforementioned members is rotatably inserted into a predetermined rotation hole 27a so that the outer periphery of the cylinder 20 is rotatably connected to one of the members.

[0017] As shown in FIG. 1, the anti - detachment cap 80 has a rod insertion port 81 formed to penetrate at its central portion, having a shape conforming to the shape of the rod 30, and can be inserted into the cylinder 20 while restricting the rotation of the rod 30. Also, a plurality of locking protrusions 82 project from a predetermined portion of the outer periphery of the anti - detachment cap 80. By locking each locking protrusion 82 to each corresponding locking hole 23a of the cylinder 20 (see FIG. 2), the anti - detachment cap 80 is attached to the opening 23 of the cylinder 20 (see FIG. 8). This anti - detachment cap 80 abuts against the piston 40 when the rod 30 is pulled out to the maximum from the opening 23 of the cylinder 20, preventing the rod 30 and the piston 40 from detaching from the cylinder 20.

[0018] Next, the rod 30 will be described.

[0019] This rod 30 is movably inserted into the cylinder 20 through the opening 23 of the cylinder 20 and slides in the axial direction of the cylinder 20 within the cylinder 20.

[0020] As shown in FIGS. 1 and 4, the rod 30 of this embodiment has a shaft portion 31 that is substantially long plate-shaped and extends in one direction. A connecting piece 33 provided with a connecting hole 33a is provided at one longitudinal end of the shaft portion 31. A connecting shaft (not shown) of the other member described above is inserted into the connecting hole 33a so that the rod 30 is rotatably connected to the other member. Further, as shown in FIG. 4, on both sides of the shaft portion 31, a pair of side walls 35, 35 that are long plate-shaped and extend parallel to each other via a plurality of ribs 35a are disposed. Each side wall 35 is disposed opposite to the inner surface of the rod insertion port 81 of the detachment prevention cap 80 to restrict the rotation of the rod 30.

[0021] Next, the piston 40 will be described.

[0022] As shown in FIGS. 3 and 4, the piston 40 of this embodiment is connected to the other longitudinal end of the rod 30, and an annular groove 50 is formed on its outer periphery, and it is integrally formed with the rod 30.

[0023] Referring also to FIG. 8, the piston 40 has a substantially cylindrical peripheral wall portion 41 that extends a predetermined length along the axial direction of the rod 30, and a first annular wall portion 42 and a second annular wall portion 43 that are connected to one axial end and the other axial end of the peripheral wall portion 41 and project annularly outward in the radial direction from the outer peripheral surface of the peripheral wall portion 41. The first annular wall portion 42 and the second annular wall portion 43 project orthogonally to the axis P of the piston 40 and are parallel to each other. Further, the axial base end portion of the rod 30 is connected to the outer surface of the first annular wall portion 42 (the surface opposite to the surface facing the second annular wall portion 43), and the piston 40 and the rod 30 are integrated.

[0024] Note that, the surface of the first annular wall portion 42 facing the second annular wall portion 43 is defined as the inner surface 42a of the first annular wall portion 42, and the surface of the second annular wall portion 43 facing the first annular wall portion 42 is defined as the inner surface 43a of the second annular wall portion 43. Also, the protruding amount (radial length) of the first annular wall portion 42 from the axis P of the piston 40 is the same as that of the second annular wall portion 43 from the axis P of the piston 40. Further, as shown in FIG. 3, in the inner surface 42a of the first annular wall portion 42, in a predetermined circumferential range, a recess 45 that is recessed at a predetermined depth with respect to the thickness direction of the first annular wall portion 42 is formed. Also, as shown in FIG. 8, at the tip end portion of the first annular wall portion 42 in the protruding direction, a chamfered portion 42b chamfered at a predetermined angle is formed on the inner surface 42a side thereof.

[0025] Also, as shown in FIG. 3, inside the peripheral wall portion 41 of the piston 40, a plurality of cylindrical walls 46, 47, 48 are provided concentrically with respect to the axis P of the piston 40.

[0026] And, the space surrounded by the peripheral wall portion 41, the first annular wall portion 42, and the second annular wall portion 43 forms an annular groove 50.

[0027] Referring also to FIG. 8, at the bottom of the annular groove 50 (which can also be said to be the outer peripheral portion of the peripheral wall portion 41), a deep bottom portion 51 arranged on the damper braking direction F1 side and a shallow bottom portion 52 arranged on the side opposite to the damper braking direction F1 and shallower than the deep bottom portion 51 are provided.

[0028] In the case of this embodiment, the deep bottom portion 51 is the bottom of the annular groove 50 and is arranged on the first annular wall portion 42 side, and is formed to be parallel to the axial direction of the piston 40 (the direction along the axis P of the piston 40). Also, the depth of the deep bottom portion 51, that is, the radial length of the deep bottom portion 51 from the outer peripheral surface of the piston (the radial length from the tops of both annular wall portions 42, 43) is denoted as "H1".

[0029] On one hand, the shallow bottom portion 52 in this embodiment is the bottom of the annular groove 50, is disposed on the side of the second annular wall portion 43, and is formed to be parallel to the axial direction of the piston 40. Also, let the depth of the shallow bottom portion 52, that is, the radial length of the shallow bottom portion 52 from the outer peripheral surface of the piston be "H2". The depth H2 of this shallow bottom portion 52 is smaller than the depth H1 of the deep bottom portion 51, and the shallow bottom portion 52 is shallower than the deep bottom portion 51. That is, the "shallow bottom" in the present invention means that the depth (radial length) from the outer peripheral surface of the piston is smaller than the depth from the outer peripheral surface of the piston of the deep bottom portion.

[0030] Further, between the deep bottom portion 51 and the shallow bottom portion 52, a portion that inclines at a larger angle with respect to the angle of the deep bottom portion 51 with respect to the axial direction of the piston 40 and the angle of the shallow bottom portion 52 with respect to the axial direction of the piston 40 is provided.

[0031] In the case of this embodiment, as shown in FIG. 8, between the deep bottom portion 51 and the shallow bottom portion 52, that is, on the surface of the deep bottom portion 51 opposite to the inner surface 42a of the first annular wall portion 42 and on the surface of the shallow bottom portion 52 opposite to the inner surface 43a of the second annular wall portion 43, an inclined portion 53 is provided in which the inclination angle θ (the angle with respect to the line segment P' parallel to the axis P of the piston 40) with respect to the axial direction of the piston 40 is 90° (it can be said that the inclination angle is perpendicular). In other words, between the deep bottom portion 51 and the shallow bottom portion 52, a stepped portion is provided by the inclined portion 53.

[0032] Also, as shown in FIG. 3, the deep bottom portion 51 has a shallow portion 55 and a deep portion 56 in the circumferential direction of the annular groove 50. Similarly, the shallow bottom portion 52 also has a shallow portion 57 and a deep portion 58 in the circumferential direction of the annular groove 50.

[0033] The shallow portion 55 of the deep bottom portion 51 is formed such that its depth from the outer peripheral surface of the piston is smaller than that of the deep portion 56, and the shallow portion 57 of the shallow bottom portion 52 is also formed such that its depth from the outer peripheral surface of the piston is smaller than that of the deep portion 58. Also, the deep portion 58 of the shallow bottom portion 52 is formed such that its depth from the outer peripheral surface of the piston is smaller than that of the shallow portion 55 of the deep bottom portion 51. Further, as shown in FIGS. 4 and 5, the shallow portions 55 and 57 of the deep bottom portion 51 and the shallow bottom portion 52 are shorter in width along the circumferential direction than the recess 45 formed on the inner surface 42a of the first annular wall portion 42, and are provided so as to be located at the circumferential intermediate portion of the recess 45.

[0034] Next, the seal ring 60 will be described.

[0035] As shown in FIGS. 6 and 7, this seal ring 60 is made of an elastic material such as rubber or elastomer, and has a substantially annular base portion 61. The inner diameter D of this base portion 61 is larger than the outer diameters of the deep bottom portion 51 and the shallow bottom portion 52 which are the bottoms of the annular groove 50, and the axial length L thereof is formed smaller than the axial width of the annular groove 50 (the length between the first annular wall portion 42 and the second annular wall portion 43), and as shown in FIG. 8, it is arranged on the outer periphery of the annular groove 50. Note that since the axial length L of the base portion 61 is formed smaller than the axial width of the annular groove 50, the seal ring 60 can move axially within the annular groove 50.

[0036] Also, the seal ring 60 is provided with a cylinder contact portion that contacts the inner peripheral surface of the cylinder 20 on its outer peripheral surface, and a shallow bottom contact portion that contacts the shallow bottom portion 52 on its inner peripheral surface. Note that the inner peripheral surface of the cylinder 20 means the inner peripheral surface of the wall portion 21 that constitutes the cylinder 20 in this embodiment, and the same applies in the following description.

[0037] Specifically, at the axial center of the base 61, a first annular protrusion 63 projects from its outer peripheral surface (the surface on the outer diameter side). Further, at both axial ends of the base 61, a second annular protrusion 65 and a third annular protrusion 67 project from its inner peripheral surface (the surface on the inner diameter side). Each of the annular protrusions 63, 65, and 67 projects continuously in the circumferential direction so as to form an annular shape outward in the radial direction of the base 61 from the outer peripheral surface or the inner peripheral surface of the base 61. Also, the second annular protrusion 65 is disposed on one axial end side of the base 61, that is, on the damper braking direction F1 side, and the third annular protrusion 67 is disposed on the other axial end side of the base 61, that is, on the damper return direction F2 side opposite to the damper braking direction F1.

[0038] Each of the annular protrusions 63, 65, and 67 has a substantially mountain-shaped (or flared shape) cross-sectional shape with side surfaces 63b, 63b, 65b, 65b, 67b, 67b that gradually widen from the top portions 63a, 65a, 67a at the tip in the protruding direction toward the base end side in the protruding direction. Also, the top portions 63a, 65a, 67a of each of the annular protrusions 63, 65, and 67 have a rounded shape. Further, the top portion 63a of the first annular protrusion 63 is located at the axial center of the seal ring 60. As shown in FIG. 7, the entire seal ring 60 has a cross-sectional shape that is line-symmetric with respect to an axis center line S passing through the center in the axial direction (a line orthogonal to the axial direction of the seal ring 60 and passing through the top portion 63a of the first annular protrusion 63).

[0039] Also, the thickness dimension in the radial direction of the seal ring 60, that is, the length from the top portion 63a of the first annular protrusion 63 to the top portions 65a of the second annular protrusion 65 and 67a of the third annular protrusion 67, is larger than the length from the inner peripheral surface of the cylinder 20 to the shallow bottom portion 52 of the annular groove 50. As a result, when the piston 40 is inserted into the cylinder 20 with the seal ring 60 mounted in the annular groove 50, the top portion 63a of the first annular protrusion 63 is pressed against the inner peripheral surface of the cylinder 20.

[0040] That is, the top 63a of the first annular protrusion 63 is always in contact with the inner peripheral surface of the cylinder 20 (see FIG. 8), and this first annular protrusion 63 forms the "cylinder contact portion" in the present invention. Note that the above "always" means all the states that the piston 40 can take in the cylinder 20, including the state where the piston 40 is stationary, the state where the piston 40 moves in the damper braking direction F1, and the state where the piston 40 moves in the damper return direction F2 (the same applies in the following description).

[0041] Also, the top 67a of the third annular protrusion 67 is always in contact with the shallow bottom portion 52 (see FIG. 8), and this third annular protrusion 67 forms the "shallow bottom contact portion" in the present invention.

[0042] And in this seal ring 60, the center C1 of the cylinder contact portion (the first annular protrusion 63) and the center C2 of the shallow bottom contact portion (the third annular protrusion 67) are displaced in the axial direction of the seal ring 60, and the inner peripheral surface of the seal ring 60 is configured not to contact the deep bottom portion 51 when the piston 40 moves in the damper braking direction F1. Further, when the piston 40 moves in the damper return direction F2 opposite to the damper braking direction F1, a part of the inner peripheral surface of the seal ring 60 is configured to deform toward the deep bottom portion 51 side.

[0043] In the case of this embodiment, the center C1 of the cylinder contact portion passes through the axial center of the first annular protrusion 63 (the location where the top 63a of the first annular protrusion 63 is located) and means a position orthogonal to the axial direction of the seal ring 60 (the same position as the axial center line S). Also, the center C2 of the shallow bottom contact portion passes through the axial center of the third annular protrusion 67 (the location where the top 67a of the third annular protrusion 67 is located) and means a position orthogonal to the axial direction of the seal ring 60.

[0044] Furthermore, the annular protrusion (second annular protrusion 65) located on the damper braking direction F1 side is positioned at the bottom portion 51, and is configured not to contact the bottom portion 51 when the piston 40 moves in the damper braking direction F1. That is, the second annular protrusion 65 is configured such that even when the piston 40 moves in the damper braking direction F1, the top portion 65a thereof does not contact the bottom portion 51.

[0045] Here, the operation of the seal ring 60 in the annular groove 50 when the piston 40 moves in the damper braking direction F1 and when the piston 40 moves in the damper return direction F2 will be described.

[0046] In a state where the piston 40 is stationary, the seal ring 60 is disposed in the annular groove 50 in a state where the top portion 63a of the first annular protrusion 63 is in contact with (pressed against) the inner peripheral surface of the cylinder 20 and the top portion 67a of the third annular protrusion 67 is in contact with the shallow bottom portion 52.

[0047] From this state, when the piston 40 moves in the damper braking direction F1, a frictional force F1' opposite to the damper braking direction F1 acts on the first annular protrusion 63 from the inner peripheral surface of the cylinder 20.

[0048] Then, since the seal ring 60 is pushed in the direction of the frictional force F1' in the annular groove 50, the other end in the axial direction of the base portion 61 of the seal ring 60 abuts against the inner surface 43a of the second annular wall portion 43 of the annular groove 50, and the posture of the seal ring 60 is maintained by the strut of the third annular protrusion 67 in contact with the shallow bottom portion 52.

[0049] In the above state, the gap between the inner surface 43a of the second annular wall portion 43 and the other end in the axial direction of the base portion 61 is sealed, and the gap between the inner peripheral surface of the cylinder 20 and the outer peripheral surface of the seal ring 60 is also sealed. As a result, the first chamber R1 in the cylinder 20 is depressurized, and as a result, the damper braking force is exerted.

[0050] On the one hand, when the piston 40 moves in the damper return direction F2, a frictional force F2' opposite to the damper return direction F2 acts on the first annular protrusion 63 from the inner peripheral surface of the cylinder 20.

[0051] Then, with the third annular protrusion 67 in contact with the shallow bottom portion 52 as a fulcrum, one axial end portion side of the seal ring 60 deforms toward the deep bottom portion 51 as shown by the arrow F3 in FIG. 8. In this embodiment, the seal ring 60 deforms (tilts) so as to roll with the third annular protrusion 67 as a fulcrum, and the second annular protrusion 65 deeply enters into the deep bottom portion 51, and its top portion 65a approaches or abuts against the deep bottom portion 51. As a result, the pressing contact force of the first annular protrusion 63 against the inner peripheral surface of the cylinder 20 decreases, and the frictional resistance between the inner peripheral surface of the cylinder 20 and the first annular protrusion 63 decreases.

[0052] Further, the seal ring 60 is configured to always contact the shallow portion 57 and the deep portion 58 of the shallow bottom portion 52.

[0053] That is, as shown by the two-dot chain line in FIG. 5, in a state where the seal ring 60 is mounted in the annular groove 50, the inner peripheral portion of the seal ring 60 (here, although not shown in the figure, the top portion 67a at a predetermined circumferential position of the third annular protrusion 67) contacts the shallow portion 57 of the shallow bottom portion 52, and the portion other than the inner peripheral portion of the seal ring 60 that contacts the shallow portion 57 abuts against the deep portion 58 of the shallow bottom portion 52.

[0054] Also, in this embodiment, when the piston 40 moves in the damper return direction F2, as shown in FIG. 9, a predetermined circumferential portion on one axial end portion side of the seal ring 60 deforms so as to enter into the recess 45 provided on the inner surface 42a of the first annular wall portion 42 of the annular groove 50, and the circumferential corresponding portion on the other axial end portion side of the seal ring 60 (the portion corresponding to the portion that enters and deforms into the recess 45) separates from the inner surface 43a of the second annular wall portion 43 of the annular groove 50 to create a gap.

[0055] As a result, as shown by the arrow in Fig. 9, the air in the first chamber R1 within the cylinder 20 sequentially passes through the following clearances and flows out toward the second chamber R2 side of the cylinder 20: (1) the clearance between a circumferentially predetermined portion on the axially other end side of the seal ring 60 and the inner surface 43a of the second annular wall portion 43; (2) the clearance between the third annular protrusion 67 of the seal ring 60 and the deep portion 58 of the shallow bottom portion 52; (3) the clearance between the seal ring 60 and the deep bottom portion 51 (particularly the clearance between the seal ring 60 and the deep portion 56 of the deep bottom portion 51); and (4) the clearances between both side portions of the portion of the seal ring 60 that has entered the recess 45 on the axially one end side and the inner surface 42a of the first annular wall portion 42. Thereby, the damper braking force is released. That is, an exhaust passage is formed for exhausting the air in the first chamber R1 to the second chamber R2 side when the piston 40 moves in the damper return direction F2.

[0056] (Modification example) The shapes and structures of the cylinder, rod, piston, seal ring, etc. that constitute the damper device in the present invention are not limited to the above-described aspects.

[0057] The wall portion 21 of the cylinder 20 in this embodiment has a substantially cylindrical shape. However, as the wall portion of the cylinder, for example, it may be made into a substantially square tube shape or a thin tube shape (a tube shape presenting a thin box shape). In this case, it is preferable that the rod, piston, seal ring, seal cap, detachment prevention cap, etc. also have shapes corresponding to the wall portion of the cylinder.

[0058] Also, in this embodiment, the cylinder 20 has an end wall 25 disposed on the axially other end side, and the through hole of this end wall 25 is configured to be opened and closed by the seal cap 70. However, for example, an end wall that closes the other end of the cylinder may be provided.

[0059] Furthermore, the rod 30 in this embodiment is composed of a shaft portion 31 and a pair of side walls 35, 35 disposed on both sides thereof via a plurality of ribs 35a. However, as the rod, for example, a structure composed only of a shaft portion having a long plate shape, a cylindrical shape, etc. may be sufficient as long as the piston can be continuously provided.

[0060] Further, the pair of annular wall portions 42 and 43 in the piston 40 of this embodiment project orthogonally to the axis P of the piston 40 and at the same height. However, these annular wall portions may be inclined at an angle other than 90° with respect to the axis of the piston, for example, or one or both of them may have different protruding amounts.

[0061] Furthermore, the deep bottom portion 51 and the shallow bottom portion 52 of the annular groove 50 are parallel to the axial direction of the piston 40. However, as the shallow bottom portion and the deep bottom portion, for example, they may be tapered and inclined at a predetermined angle with respect to the axial direction of the piston, or may be curved or stepped.

[0062] Also, the inclined portion 53 provided between the deep bottom portion 51 and the shallow bottom portion 52 has an inclination angle of 90° (perpendicular) with respect to the axial direction of the piston 40. However, as this inclined portion, for example, it may be inclined at an angle other than 90° with respect to the axial direction of the piston.

[0063] Also, in this embodiment, by providing a deep portion 58 or the like in the shallow bottom portion 52, an exhaust flow path for the air in the first chamber R1 when the piston 40 moves in the damper return direction F2 is configured (see paragraph 0055). However, as such an exhaust flow path, for example, it may be configured by providing a concave groove extending in the axial direction in the shallow bottom portion.

[0064] Furthermore, as the seal ring, for example, it may have a shape as shown in FIG. 10.

[0065] That is, the seal ring 60A shown in FIG. 10 does not have the first annular protrusion 63 like the seal ring 60 shown in FIG. 7, and has the same shape as the seal ring 60 except that the outer peripheral surface of the base portion 61 is slightly curved. And the top portion 61a (the portion located at the center in the axial direction) of the outer peripheral surface of the base portion 61 is the cylinder contact portion. Note that, similar to the seal ring 60, for this seal ring 60A as well, the center C1 of the cylinder contact portion and the center C2 of the shallow bottom contact portion (the third annular protrusion 67) are displaced in the axial direction of the seal ring 60.

[0066] Also, in this embodiment, when the piston 40 moves in a direction away from the end wall 25 of the cylinder 20 (when the piston 40 moves in the damper braking direction F1), the braking force due to the decompression of the first chamber R1 acts, and when the piston 40 moves in a direction approaching the end wall 25 of the cylinder 20 (when the piston 40 moves in the damper return direction F2), the braking force is configured to be released. However, conversely, it may be configured such that the damper braking force acts when the piston 40 moves in a direction approaching the end wall 25 of the cylinder 20, and the damper braking force is released when the piston 40 moves in a direction away from the end wall 25 of the cylinder 20. This will be described in another embodiment shown in FIG. 11.

[0067] Also, in this embodiment, one member is a fixed body such as a housing portion of an instrument panel, and the other member is an opening / closing body such as a glove box or a lid. However, the pair of members is not particularly limited as long as they can approach and separate from each other.

[0068] Furthermore, in this embodiment, an air chamber (first chamber R1) is formed in the cylinder 20 on the side of the rod 30 insertion direction from the seal ring 60. However, an air chamber may be provided on the side opposite to the rod insertion direction within the cylinder. For example, an exhaust hole is formed in the end wall of the cylinder, and a seal cap that can open and close the exhaust hole is attached to the periphery of the exhaust hole. Furthermore, the cap attached to the opening at one end of the cylinder has a structure capable of sealing the periphery of the opening and a structure capable of sealing the gap between the rod insertion hole and the rod inserted through the rod insertion hole, and a sealed air chamber is provided on the side opposite to the rod insertion direction within the cylinder. Then, when the piston moves in the direction away from the end wall of the cylinder (when it moves in the direction opposite to the rod insertion direction), the air chamber is pressurized, and thus the damper braking force is exerted. When the piston moves close to the end wall of the cylinder (when it moves toward the rod insertion direction side), the seal cap opens the exhaust hole, the air in the air chamber is exhausted, and the damper braking force is released.

[0069] (Function and Effect) Next, the function and effect of the damper device 10 having the above configuration will be described.

[0070] In this damper device 10, when one member (such as a fixed body) and the other member (such as an opening / closing body) are in a state of approaching each other, the piston 40 is stationary within the cylinder 20. In this state, the top 63a of the first annular protrusion 63 contacts the inner peripheral surface of the cylinder 20, and the top 67a of the third annular protrusion 67 contacts the shallow bottom portion 52, and the seal ring 60 is disposed within the annular groove 50.

[0071] From the above state, when one member moves in a direction away from the other member (when the opening / closing body opens from the fixed body), the piston 40 moves in the damper braking direction F1 within the cylinder 20, and the rod 30 is pulled out from the opening 23 side of the cylinder 20. Then, as described in paragraph 0049 above, since the first chamber R1 within the cylinder 20 is depressurized, a damper braking force is applied to the piston 40, and the other member can be slowly moved with respect to one member (the opening / closing body can be slowly opened from the fixed body).

[0072] Also, when one member is moved in a direction approaching the other member (when the opening / closing body is closed with respect to the fixed body), the piston 40 moves in the damper return direction F2 within the cylinder 20, and the rod 30 is pushed into the cylinder 20.

[0073] Then, a frictional force F2' opposite to the damper return direction F2 acts on the first annular protrusion 63, which is the cylinder contact portion, from the inner peripheral surface of the cylinder 20. Therefore, with the third annular protrusion 67, which is the shallow bottom contact portion in contact with the shallow bottom portion 52, as a fulcrum, one axial end portion side of the seal ring 60 deforms toward the deep bottom portion 51 side as shown by the arrow F3 in FIG. 8. Here, the seal ring 60 deforms so as to roll with the third annular protrusion 67 as a fulcrum. As a result, the pressure contact force of the first annular protrusion 63 against the inner peripheral surface of the cylinder 20 becomes low, so that the frictional resistance between the inner peripheral surface of the cylinder 20 and the first annular protrusion 63 can be reduced, and the operating force of the piston 40 when the piston 40 moves in the damper return direction F2 can be reduced. Further, when the piston 40 moves in the damper return direction F2, as described in paragraphs 0054 and 0055, a part of the seal ring 60 enters the concave portion 45 of the annular groove 50, and the air in the first chamber R1 flows out to the second chamber R2 side (see FIG. 9), so that the damper braking force is released. Note that the damper device having the seal ring 60A shown in FIG. 10 also exhibits the same effect.

[0074] Further, in this embodiment, as shown in FIG. 8, between the deep bottom portion 51 and the shallow bottom portion 52, there is provided a portion (inclined portion 53) that inclines at a larger angle with respect to the angle of the deep bottom portion 51 with respect to the axial direction of the piston 40 and the angle of the shallow bottom portion 52 with respect to the axial direction of the piston 40.

[0075] According to the above aspect, by providing the inclined portion 53 that inclines at a larger angle with respect to the axial direction of the piston 40 between the deep bottom portion 51 and the shallow bottom portion 52, a portion that becomes deeper in a stepped manner can be provided between the deep bottom portion 51 and the shallow bottom portion 52. When the piston 40 moves in the damper return direction F2, the seal ring 60 can be more easily deformed by the deep bottom portion 51 side, and the operating force in the damper return direction F2 can be more effectively reduced.

[0076] Also, since the angle of the shallow bottom portion 52 with respect to the axial direction of the piston 40 can be made small, a shallow bottom contact portion (here, the third annular protrusion 67) can be stably brought into contact with the shallow bottom portion 52, and a stable damper braking force can be obtained.

[0077] Furthermore, in this embodiment, the seal ring 60 has annular protrusions 65 and 67 protruding from the inner circumferences of both axial ends. The annular protrusion (third annular protrusion 67) located on the side opposite to the damper braking direction F1 forms a shallow bottom contact portion, and the third annular protrusion 67 is always located at the shallow bottom portion 52 and is in contact with the shallow bottom portion 52. The annular protrusion (second annular protrusion 65) located on the damper braking direction F1 side is located at the deep bottom portion 51 and is configured not to contact the deep bottom portion 51 when the piston 40 moves in the damper braking direction F1.

[0078] According to the above aspect, the third annular protrusion 67 located on the side opposite to the damper braking direction F1 can ensure the wall thickness of the portion of the seal ring 60 on the side opposite to the damper braking direction F1. When the piston 40 moves in the damper braking direction F1, the seal ring 60 can be maintained in a stable posture, and it is easy to maintain the sealing performance between the inner circumferential surface of the cylinder 20 and the outer circumferential surface of the piston 40 by the seal ring 60.

[0079] Further, since the annular protrusions 65 and 67 are provided on the inner circumferences of both axial ends of the seal ring 60, when the piston 40 moves in the damper return direction F2 and the seal ring 60 tends to deform toward the deep bottom portion 51, the inner circumferential portion 61b (see FIG. 7) of the intermediate portion in the axial direction of the seal ring 60 can be made less likely to contact between the deep bottom portion 51 and the shallow bottom portion 52. As a result, the second annular protrusion 65 located on the damper braking direction F1 side can be made more likely to enter the deep bottom portion 51, so that the seal ring 60 can be easily deformed and excessive deformation of the seal ring 60 can be suppressed.

[0080] Also, in this embodiment, the shallow bottom portion 52 has a shallow portion 57 and a deep portion 58 in the circumferential direction of the annular groove 50, and the seal ring 60 is configured to always contact the shallow portion 57 and the deep portion 58 of the shallow bottom portion 52 (see FIGS. 3 and 5).

[0081] According to the above aspect, since the seal ring 60 is configured to always contact the shallow portion 57 and the deep portion 58 of the shallow bottom portion 52, the shallow portion 57 maintains the frictional force between the inner circumferential surface of the cylinder 20 and the seal ring 60, and a predetermined damper braking force can be ensured. Further, the deep portion 58 of the shallow bottom portion 52 can reduce the crushing margin of the seal ring 60 when the piston 40 moves in the damper return direction F2, so that excessive crushing deformation of the seal ring 60 can be suppressed. As a result, when the piston 40 changes from a stationary state or a state of moving in the damper braking direction F1 to moving in the damper return direction F2, the responsiveness is enhanced, the frictional force between the inner circumferential surface of the cylinder 20 and the seal ring 60 can be smoothly reduced, and the operating force of the piston 40 can be quickly reduced. Therefore, the balance between the damper braking force when the piston 40 moves in the damper braking direction F1 and the operating force when the piston 40 moves in the damper return direction F2 can be achieved.

[0082] (Other Embodiments of the Damper Device) FIG. 11 shows another embodiment of the damper device according to the present invention. The same reference numerals are given to substantially the same parts as those in the above embodiment, and the description thereof is omitted.

[0083] In the damper device 10A of this embodiment, contrary to the damper device 10 shown in FIGS. 1 to 10, when the piston 40 moves in a direction approaching the end wall 25 of the cylinder 20, a braking force acts, and when the piston 40 moves in a direction away from the end wall 25 of the cylinder 20, the braking force is released.

[0084] That is, in the case of this embodiment, the arrangement of the deep bottom portion 51 and the shallow bottom portion 52 provided at the bottom of the annular groove 50 is opposite to the arrangement of the deep bottom portion 51 and the shallow bottom portion 52 in the damper device 10 shown in FIGS. 1 to 10.

[0085] Specifically, as shown in FIG. 11, at the bottom of the annular groove 50, the deep bottom portion 51 is arranged on the damper braking direction F1 side, and the shallow bottom portion 52 is arranged on the damper return direction F2 side. Further, the other end of the cylinder 20 is closed by the end wall 25. Furthermore, an orifice 49 that communicates the first chamber R1 and the second chamber R2 with each other is formed at a predetermined position of the piston 40.

[0086] When one member moves in a direction approaching the other member and the piston 40 moves in the damper braking direction F1, the first chamber R1 in the cylinder 20 is pressurized, and a damper braking force is applied to the piston 40. Also, when one member moves in a direction away from the other member and the piston 40 moves in the damper return direction F2, the axially other end portion of the seal ring 60 deforms toward the deep bottom portion 51 side, so that the frictional resistance between the inner peripheral surface of the cylinder 20 and the first annular protrusion 63 decreases, and the operating force of the piston 40 can be reduced.

[0087] (Still Another Embodiment of the Damper Device) Figures 12 to 18 show still other embodiments of the damper device according to the present invention. In addition, the same reference numerals are given to substantially the same parts as those in the above embodiment, and the description thereof is omitted.

[0088] In the damper device 10B of this embodiment, mainly, the shape of the cylinder 20B, the shape of the piston 40B, and the shape of the annular groove 50B are different from those in the above embodiment.

[0089] As shown in FIG. 12, the cylinder 20B has a wall portion 21 extending in a cylindrical shape, and a cross section of the wall portion 21 orthogonal to the axial direction has a cross-sectional shape having a major axis X and a minor axis Y, and is a thin cylindrical shape (a cylindrical shape presenting a thin box shape) in which the major axis X side is wide and the minor axis Y side is narrow.

[0090] In addition, as shown in FIGS. 12 and 17, in the wall portion 21 of the cylinder 20B, the direction along the major axis X is defined as the "major axis direction", and the direction along the minor axis Y is defined as the "minor axis direction". The same applies to the components of the piston 40B described later.

[0091] Specifically, the wall portion 21 has a pair of major axis side wall portions 21a, 21a extending linearly in the major axis direction and arranged to face each other in parallel, and a pair of minor axis side wall portions 21b, 21b arranged in the minor axis direction and connecting both ends of the pair of major axis side wall portions 21a, 21a to each other and having an arcuate bent shape.

[0092] In addition, one end portion side in the axial direction of the wall portion 21 is open, and an opening 23 is provided. Further, locking holes 23a, 23a are respectively formed in the major axis side wall portions 21a, 21a that are opposed to each other at the periphery of the opening 23.

[0093] An end wall (not shown) is arranged at the other end portion in the axial direction of the wall portion 21, and the other end portion of the wall portion 21 is closed.

[0094] Also, as shown in FIG. 12, the anti-removal cap 80B attached to the opening 23 of the cylinder 20B has a peripheral wall portion 81a that conforms to the wall portion 21 of the cylinder 20B.

[0095] Next, the piston 40B will be described.

[0096] The piston 40B of this embodiment has a cross-sectional shape having a major axis and a minor axis that conform to the wall portion 21 of the cylinder 20B.

[0097] That is, as shown in FIG. 17, the peripheral wall portion 41 of the piston 40B in this embodiment linearly extends in the major axis direction and has a pair of major axis side wall portions 41a, 41a that are arranged to face each other in parallel, and is arranged in the minor axis direction, and connects both ends of the pair of major axis side wall portions 41a, 41a to each other and has a pair of minor axis side wall portions 41b, 41b that form an arcuate bent shape.

[0098] Also, as shown in FIG. 17, the deep bottom portion 51, which is the bottom portion of the annular groove 50 (the outer peripheral portion of the peripheral wall portion 41) and is arranged on the damper braking direction F1 side, has a pair of major axis side deep bottom portions 51a, 51a formed on the pair of major axis side wall portions 41a, 41a side and a pair of minor axis side deep bottom portions 51b, 51b formed on the pair of minor axis side wall portions 41b, 41b side.

[0099] Furthermore, on the outer periphery of the piston 40B, at least one of the both side portions located in the major axis direction has a concave groove shape formed deeper than the deep bottom portion 51 and extending in the axial direction, and an air circulation groove 54 through which air flows is formed when the piston 40B moves in the return direction opposite to the damper braking direction.

[0100] In the case of this embodiment, as shown in FIG. 15, the air circulation groove 54 is formed at a position offset toward one of the minor axis side wall portions 41b from the central portion in the major axis direction of one of the pair of major axis side wall portions 41a, 41a of the peripheral wall portion 41.

[0101] Further, as shown in Fig. 18, the depth of the air flow groove 54 (the radial length of the air flow groove 54 from the outer peripheral surface of the piston) is formed deeper than the depth H1 of the deep bottom portion 51 (the radial length of the deep bottom portion 51 from the outer peripheral surface of the piston), and is in the shape of a concave groove extending along the axial direction of the piston 40B.

[0102] When the piston 40B moves in the damper return direction F2 (see Fig. 18), which is opposite to the damper braking direction F1, a predetermined circumferential portion on the axial one - end side of the seal ring 60 deforms so as to enter the recess 45 of the first annular wall portion 42 of the annular groove 50B, and the corresponding circumferential portion on the axial other - end side of the seal ring 60 separates from the inner surface 43a of the second annular wall portion 43 of the annular groove 50, creating a gap.

[0103] Then, as shown by the arrow K in Fig. 18, the air in the first chamber R1 in the cylinder 20B flows into the air flow groove 54 from the gap between the predetermined circumferential portion on the axial other - end side of the seal ring 60 and the inner surface 43a of the second annular wall portion 43, and then flows out to the second chamber R2 side of the cylinder 20B through the air flow groove 54, so that the damper braking force is released.

[0104] Also, as shown in Figs. 14 to 18, from the bottom surface of the long - axis - side deep bottom portion 51a, protrusions 59 are provided so as to be able to contact the inner peripheral surface of the seal ring 60 when the piston 40B moves at least in the damper return direction F2 (see Fig. 18).

[0105] Furthermore, a plurality of protrusions 59 are provided at a predetermined interval in the long - axis direction of the piston 40B from the bottom surface of the long - axis - side deep bottom portion 51a. Also, the protrusions 59 are provided at least on both sides of the air flow groove 54 in the long - axis direction of the piston 40B.

[0106] More specifically, each protrusion 59 in this embodiment has a thin-walled protrusion shape protruding from the bottom surface of the long-axis side deep bottom portion 51a at a predetermined height and has a rectangular shape (here, a substantially square shape) (see FIG. 14). Further, the ceiling surface of each protrusion 59 (the surface that protrudes highest from the bottom surface of the long-axis side deep bottom portion 51a) has a flat surface shape without irregularities.

[0107] In addition, the protruding height (the height of the ceiling surface) of each protrusion 59 from the bottom surface of the long-axis side deep bottom portion 51a is set to be below the bottom surface of the shallow bottom portion 52. In this embodiment, as shown in FIG. 18, the height of the ceiling surface of each protrusion 59 is lower than the bottom surface of the shallow bottom portion 52.

[0108] Furthermore, in the case of this embodiment, as shown in FIGS. 14, 15, and 17, on the bottom surface of one long-axis side deep bottom portion 51a, a pair of protrusions 59, 59 protrude from both side edges in the long-axis direction of the air flow groove 54, and among these pair of protrusions 59, 59, the other protrusion 59 protrudes from a position spaced apart in the long-axis direction with respect to one protrusion 59 (the protrusion 59 located below the paper surface in FIGS. 14 and 15), and a total of three protrusions 59 protrude.

[0109] On the other hand, as shown in FIGS. 16 and 17, three protrusions 59 protrude from the bottom surface of the other long-axis side deep bottom portion 51a at predetermined intervals in the long-axis direction.

[0110] That is, in this embodiment, a total of six protrusions 59 protrude, three from each long-axis side deep bottom portion 51a.

[0111] As shown in FIG. 18, in the seal ring 60 in this embodiment, the top 67a of the third annular protrusion 67 located on the damper return direction F2 side is always in contact with the shallow bottom portion 52 of the annular groove 50, and the top 65a of the second annular protrusion 65 located on the damper braking direction F1 side is always in contact with the ceiling surface of the protrusion 59. That is, the protrusion 59 is always in contact with the second annular protrusion 65 (including when the piston 40B moves in the damper return direction F2).

[0112] Further, as described above, the second annular protrusion 65 and the protrusion 59 are configured to be in contact with each other, but the second annular protrusion 65 is not configured to contact the deep bottom portion 51 itself.

[0113] Note that the number and layout of the protrusions are not particularly limited, but it is preferable that at least one protrusion is provided on each major-axis-side deep bottom portion 51a. Further, the shape of the protrusion may be, for example, a circular protrusion, an elliptical protrusion, a narrow rib shape, etc., as long as it can contact the inner peripheral surface of the seal ring when the piston moves in the damper return direction.

[0114] Also, in this embodiment, annular protrusions 65 and 67 project from the inner peripheral surfaces at both axial ends of the seal ring 60, and the annular protrusion (third annular protrusion 67) located on the side opposite to the damper braking direction F1 forms a shallow bottom contact portion, and the third annular protrusion 67 is always located at the shallow bottom portion 52 and contacts the shallow bottom portion 52. The second annular protrusion 65 located on the damper braking direction F1 side is located at the deep bottom portion 51 and is configured not to contact the deep bottom portion 51 when the piston 40B moves in the damper braking direction F1. The protruding amounts of the third annular protrusion 67 located on the side opposite to the damper braking direction F1 and the second annular protrusion 65 located on the damper braking direction F1 side from the inner peripheral surface at the axial middle portion of the seal ring 60 are the same, and the protrusion 59 is configured to be able to contact the second annular protrusion 65 located on the damper braking direction F1 side.

[0115] Next, the operation and effects of the damper device 10B having the above configuration will be described.

[0116] That is, in the damper device 10B of this embodiment, a protrusion 59 that can contact the inner peripheral surface of the seal ring 60 when the piston 40B moves in the damper return direction F2 projects from the bottom surface of the major-axis-side deep bottom portion 51a.

[0117] According to the above aspect, when the piston 40B moves in the damper return direction F2, while reducing the operating load (pushing load) of the piston 40B, it is possible to prevent the portion of the seal ring 60 located in the major axis direction, which is originally difficult to maintain a stable posture, from rolling or tilting, and it becomes easier to maintain the seal ring 60 in a stable posture. Therefore, when the piston 40B stops after moving in the damper return direction F2 and then moves again in the damper braking direction F1, a stable braking force can be exerted.

[0118] Also, in this embodiment, a plurality of protrusions 59 project from the bottom surface of the major axis side deep bottom portion 51a at a predetermined interval in the major axis direction of the piston 40B.

[0119] According to the above aspect, since a plurality of protrusions 59 project as described above, the portion of the seal ring 60 located in the major axis direction of the piston 40B is stably supported over a wide range, and the frictional force of the cylinder contact portion (first annular protrusion 63) that contacts the inner peripheral surface of the cylinder 20B is appropriately adjusted, so that while reducing the operating load when the piston 40B moves in the damper return direction F2, it becomes easier to maintain the seal ring 60 in a more stable posture.

[0120] Furthermore, in this embodiment, on the outer periphery of the piston 40B, in at least one of the both side portions located in the major axis direction, an air flow groove 54 is formed which is formed deeper than the deep bottom portion 51 and has a concave groove shape extending in the axial direction, and the protrusions 59 are provided at least on both side portions of the piston 40B in the major axis direction in the air flow groove 54.

[0121] According to the above aspect, both side portions of the air flow groove 54 are locations where the posture of the seal ring 60 is particularly difficult to stabilize. However, since the protrusions 59, 59 are provided at such locations, it becomes easier to maintain the seal ring 60 in a more stable posture.

[0122] Moreover, by adopting the configuration described in paragraph 0114, the same effects as those described in paragraph 0078 (maintaining the sealing performance between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston) and paragraph 0079 (facilitating the deformation of the seal ring 60 and suppressing excessive deformation) can be obtained.

[0123] Furthermore, there is no directionality when mounting the seal ring 60 in the annular groove 50, the seal ring 60 can be easily mounted in the annular groove 50, and when the piston 40B moves in the damper return direction F2, it becomes easier to suppress the rolling and tilting deformation of the seal ring 60.

[0124] In addition, 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.

Explanation of Reference Numerals

[0125] 10, 10A, 10B Damper device 20, 20B Cylinder 23 Opening 30 Rod 40, 40B Piston 50 Annular groove 51 Deep bottom 52 Shallow bottom 53 Inclined portion 54 Air flow groove 57 Shallow portion 58 Deep portion 59 Protrusion 60, 60A Seal ring 63 First annular protrusion 65 Second annular protrusion 67 Third annular protrusion 70 Seal cap 80, 80B Anti-disengagement cap

Claims

1. A damper device attached between a pair of members that approach and separate from each other, and that applies a braking force when the pair of members approach or separate, comprising: a cylinder having an opening at one end; a rod movably inserted into the cylinder through the opening; a piston connected to the rod and having an annular groove formed on the outer periphery; a seal ring mounted in the annular groove and pressed against the inner peripheral surface of the cylinder; at the bottom of the annular groove, a deep bottom portion disposed on the damper braking direction side and a shallow bottom portion disposed on the side opposite to the damper braking direction and having a shallower bottom than the deep bottom portion are provided; the seal ring is provided with a cylinder contact portion on the outer peripheral surface that contacts the inner peripheral surface of the cylinder and a shallow bottom contact portion on the inner peripheral surface that contacts the shallow bottom portion, and the center of the cylinder contact portion and the center of the shallow bottom contact portion are displaced in the axial direction; the inner peripheral surface of the seal ring is configured not to contact the deep bottom portion when the piston moves in the damper braking direction and to contact the shallow bottom portion when the piston moves in the return direction opposite to the damper braking direction. A damper device characterized by this.

2. Between the deep bottom portion and the shallow bottom portion, a portion that inclines at a larger angle with respect to the angle of the deep bottom portion with respect to the axial direction of the piston and the angle of the shallow bottom portion with respect to the axial direction of the piston is provided. The damper device according to Claim 1.

3. The seal ring has annular protrusions projecting from the inner peripheral surfaces at both axial ends; the annular protrusion located on the side opposite to the damper braking direction forms the shallow bottom contact portion, and the annular protrusion is always located at the shallow bottom portion and contacts the shallow bottom portion; The annular protrusion located on the damper braking direction side is located at the deep bottom portion, and is configured not to contact the deep bottom portion when the piston moves in the damper braking direction. The damper device according to Claim 1 or 2.

4. The shallow bottom portion has a shallow portion and a deep portion in the circumferential direction of the annular groove; The seal ring is configured to always contact the shallow portion and the deep portion of the shallow bottom portion. The damper device according to Claim 1 or 2.

5. The cylinder has a wall portion extending in a cylindrical shape, and a cross section of the wall portion perpendicular to the axial direction has a cross-sectional shape having a major axis and a minor axis. The piston has a cross-sectional shape having a major axis and a minor axis that fit the wall portion of the cylinder. The bottom portion has a major-axis side bottom portion formed at least in the major axis direction of the piston. The damper device according to claim 1, wherein a protrusion is provided on the bottom surface of the major-axis side bottom portion so as to be able to contact the inner peripheral surface of the seal ring when the piston moves at least in a return direction opposite to the damper braking direction. **Claim 6** The damper device according to claim 5, wherein a plurality of the protrusions are provided at a predetermined interval in the major axis direction of the piston from the bottom surface of the major-axis side bottom portion. **Claim 7** An air flow groove having a concave groove shape formed deeper than the bottom portion and extending in the axial direction is formed in at least one of both side portions located in the major axis direction on the outer periphery of the piston. The damper device according to claim 6, wherein the protrusions are provided at least on both side portions in the major axis direction of the piston in the air flow groove.

Images