Shock absorbing device and suspension device

Abstract

This shock absorbing device 2 comprises a rod guide 60 and a seal member 80 that includes: a seal lip part 91 that is provided so as to form a contact part with the rod guide 60 further toward an opening side than the rod guide 60 in the axial direction of the rod; and an outer peripheral seal part 93 that seals a gap between the seal member and the inner surface of an outer cylinder. The rod guide 60 includes: an inclined surface 724 which is provided at an end section on the opening side in an outer peripheral part and against which an inside portion of the portion in contact with the inner surface of the outer cylinder in the outer peripheral seal part 93 is pressed; and an outer peripheral recessed part 723 that is recessed from the outer peripheral surface and forms an outer peripheral flow passage for returning working fluid to a reservoir chamber between the outer peripheral recessed part and the inner surface of the outer cylinder. A notch 931 is formed in a portion pressed against the inclined surface 724 in the outer peripheral seal part 93, to form a relay flow passage through which the working fluid that has flowed through a gap between the seal lip part 91 and the rod and reached the opening part side, flows toward the outer peripheral flow passage.

Description

shock absorbers, suspension devices

[0001] The present invention relates to shock absorbers and suspension systems.

[0002] For example, the shock absorber disclosed in Patent Document 1 includes a cylinder, an outer cylinder disposed outside the cylinder and covering the cylinder, and a rod guide that closes the open ends of the cylinder and the outer cylinder and supports a rod movably inserted into the cylinder. A piston connected to the lower end of the rod is slidably inserted below the cylinder, and the piston divides the cylinder into a rod-side chamber and a piston-side chamber filled with hydraulic oil. A reservoir filled with gas and hydraulic oil is formed between the cylinder and the outer cylinder. A seal member is stacked above the rod guide, and includes an annular insert metal, an inner seal held on the inner periphery of the insert metal and in sliding contact with the outer periphery of the rod, and an outer seal held on the outer periphery of the insert metal and in close contact with the outer periphery of the rod guide and the outer cylinder. A cylindrical slide bearing is attached to the inner periphery of the guide portion of the rod guide, and the rod is slidably inserted within the slide bearing. Furthermore, the rod guide has a recess on its inner periphery and a communication hole that connects this recess to the surface of the flange facing the reservoir, allowing hydraulic oil that has passed between the rod and the slide bearing to be returned to the reservoir via the communication hole.

[0003] Patent No. 6080257

[0004] In the shock absorber of Patent Document 1, the rod guide has a communication hole that connects the reservoir to a recessed portion provided on the inner periphery thereof, which is formed as a hole that penetrates a portion of the rod guide. However, there is room for improvement in terms of easily molding the rod guide. For example, if the through hole is molded using a mold, the mold structure becomes complex and the mold cost becomes high. Furthermore, if the through hole is molded by cutting, a cutting process is required. The present invention aims to provide a shock absorber or the like that allows for easily manufacturing a rod guide.

[0005] The present invention, which has been completed with the above object in mind, comprises an inner cylinder in which a working fluid is sealed, an outer cylinder provided outside the outer periphery of the inner cylinder and forming a reservoir chamber for storing the working fluid between the inner cylinder and the outer cylinder, a piston portion that partitions a space formed within the inner cylinder, a rod having one end that holds the piston portion and the other end that protrudes from an opening of the outer cylinder, a rod guide that slidably supports the rod and has an outer periphery that contacts the inner surface of the outer cylinder, a first seal portion that is provided on the opening side of the rod guide in the axial direction of the rod to form a contact portion with the rod guide, and that seals between the rod and the outer cylinder, and and a seal member having a second seal portion that seals between the rod guide and the inner surface of the outer cylinder. The rod guide has a pressed portion provided at an end of its outer periphery on the opening side and against which an inner portion of the second seal portion that contacts the inner surface of the outer cylinder is pressed, and an outer periphery recess that is recessed from the outer periphery and forms an outer periphery flow path between the rod guide and the inner surface of the outer cylinder for returning the working fluid to the reservoir chamber. The portion of the second seal portion that is pressed against the pressed portion has a notch that forms a relay flow path for directing the working fluid that has passed through a gap between the first seal portion and the rod and reached the opening side toward the outer periphery flow path. Here, the rod guide may have a groove that communicates between the inside and outside of the contact portion. Alternatively, the rod guide may have a plurality of grooves that communicate between the inside and outside of the contact portion, and the number of notches may be greater than the number of grooves. Alternatively, either the number of grooves or the number of notches may be an even number, and the other may be an odd number. Furthermore, four or more of the notches may communicate with a plurality of the grooves. Furthermore, the rod guide may communicate with the grooves and form a circumferential flow path between the rod guide and the seal member, through which the working fluid moves in a circumferential direction. Furthermore, the seal member may have a third seal portion between the first seal portion and the second seal portion, which allows the working fluid to flow from the first seal portion to the second seal portion and prevents the working fluid from flowing from the second seal portion to the first seal portion.Furthermore, the axial tip end of the second seal portion may not be pressed against the rod guide. Furthermore, the notch may have a rectangular shape when viewed in the axial direction. Furthermore, the notch may be provided with a protrusion that protrudes from a bottom surface toward the rod guide. From another perspective, the present invention is a suspension device including the shock absorber described above and a spring disposed around the shock absorber.

[0006] According to the present invention, it is possible to provide a shock absorber or the like in which the rod guide can be easily manufactured.

[0007] FIG. 1 is a diagram showing an example of a schematic configuration of a suspension device according to a first embodiment; FIG. 2 is an enlarged view of part II of FIG. 1; FIG. 3 is a diagram showing an example of a perspective view of a rod guide and a seal member; FIG. 4 is a diagram showing an example of a flow path; FIG. 5 is a diagram showing an example of a modified cutout; FIG. 6 is a diagram showing an example of a cross section of a rod guide and a seal member according to a second embodiment; FIG. 7 is a diagram showing an example of a schematic configuration of a seal member according to a fourth embodiment; FIG. 8 is a diagram showing an example of a perspective view of a rod guide according to a fifth embodiment as seen from a second side, and an example of a perspective view of a seal member according to a fifth embodiment as seen from a first side; FIG. 9 is a diagram showing an example of a cross section of a rod guide and a seal member according to a fifth embodiment;

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <First Embodiment> Fig. 1 is a diagram showing an example of a schematic configuration of a suspension system 1 according to a first embodiment. Fig. 2 is an enlarged view of a portion II in Fig. 1 . Fig. 3 is a diagram showing an example of a perspective view of a rod guide 60 and a seal member 80. The suspension system 1 is a suspension used in a four-wheeled vehicle such as a passenger automobile, and as shown in Fig. 1 , includes a hydraulic shock absorber 2 and a coil spring 3 disposed outside the shock absorber 2. The suspension system 1 also includes a lower spring seat 4 that supports an end of the coil spring 3 on a first axial side (lower side in Fig. 1 ) of a rod 20 (described later), and an upper spring seat 5 that supports an end of the coil spring 3 on a second axial side (upper side in Fig. 1 ) of the rod 20.

[0009] The suspension 1 also includes a vehicle-side bracket 6 that is attached to the second axial end of the rod 20 to attach the suspension 1 to a vehicle, and a wheel-side bracket 7 that is fixed to a first axial end of the rod 20 in a cylinder portion 10 (described later) to attach the suspension 1 to a wheel. The suspension 1 also includes a dust cover 8 that covers at least a portion of the cylinder portion 10 and the rod 20.

[0010] Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." The axial direction is also the direction of the center line of the cylindrical inner tube 11, which will be described later. The first axial side (the lower side in FIG. 1 ) and the second axial side (the upper side in FIG. 1 ) may be simply referred to as the "first side" and the "second side," respectively. The direction intersecting the axial direction (for example, the perpendicular direction) may be referred to as the "radial direction." In the radial direction, the side of the center line of the inner tube 11 may be simply referred to as the "inner side," and the side away from the center line may be simply referred to as the "outer side."

[0011] The shock absorber 2 will be described in detail below. The shock absorber 2 includes a cylinder portion 10 that stores oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at the first end of the rod 20, and a bottom portion 40 that is provided at the first end of the cylinder portion 10. The shock absorber 2 also includes a rebound seat 50 that is fixed to the rod 20, and a rebound rubber 51 that is an annular elastic member that is arranged on the second side of the rebound seat 50, in order to absorb the impact when the rod 20 extends.

[0012] The cylinder portion 10 includes a thin-walled cylindrical inner tube 11, a thin-walled cylindrical outer tube 12 provided on the outside of the inner tube 11, and a bottom cover 13 that closes a first end of the outer tube 12. The inner tube 11 and the outer tube 12 are arranged so that the center line direction of the cylinders coincides with the axial direction. The cylinder portion 10 forms a reservoir chamber R between the outer peripheral surface of the inner tube 11 and the inner peripheral surface of the outer tube 12. The reservoir chamber R is filled with oil on the first side and gas on the second side.

[0013] The cylinder section 10 also includes a rod guide 60 that movably supports the rod 20, a bump stopper cap 15 attached to the second end of the outer cylinder 12, and a seal member 80 that prevents oil from leaking from the cylinder section 10 and prevents foreign matter from entering the cylinder section 10. The rod guide 60 and the seal member 80 will be described in detail later.

[0014] The rod 20 is a rod-shaped member extending in the axial direction. The rod 20 holds the piston portion 30 on a first side. The rod 20 is connected to, for example, the vehicle body via the vehicle-side bracket 6 on a second side.

[0015] The piston section 30 includes a piston 31, a valve group 32 that closes first ends of some of the oil passages formed in the piston 31, and a valve group 33 that closes second ends of some of the oil passages formed in the piston 31. The piston 31 contacts the inner peripheral surface of the inner cylinder 11 via a seal member provided on its outer peripheral surface, and divides the space in the inner cylinder 11 filled with oil into a first oil chamber Y1 on the first side of the piston 31 and a second oil chamber Y2 on the second side of the piston 31.

[0016] 1, the bottom portion 40 includes a valve body 41 having a plurality of oil passages passing through in the axial direction, a valve 42 provided on a first side of the valve body 41, and a valve 43 provided on a second side of the valve body 41. The valve body 41 of the bottom portion 40 separates a first oil chamber Y1 from a reservoir chamber R.

[0017] [Rod Guide 60] The rod guide 60 includes a thin-walled cylindrical guide 61 disposed inside, and a guide case 70 that holds the guide 61 inside.

[0018] The inner diameter of the guide 61 is set slightly larger than the outer diameter of the rod 20 inserted inside. For example, the inner diameter of the guide 61 is 0.1 mm to 1 mm larger than the outer diameter of the rod 20. Because the inner peripheral surface of the guide 61 comes into contact with the outer peripheral surface of the rod 20, the guide 61 is formed from a material that is more wear-resistant than the guide case 70.

[0019] The guide case 70 has a cylindrical inner cylindrical portion 71 provided on the inside, and a cylindrical outer cylindrical portion 72 provided on the outside of the inner cylindrical portion 71. The inner cylindrical portion 71 and the outer cylindrical portion 72 are integrally molded such that the outer peripheral surface of the second side portion of the inner cylindrical portion 71 and the inner peripheral surface of the first side portion of the outer cylindrical portion 72 are joined together.

[0020] The guide 61 is fitted inside the inner cylindrical portion 71. The outer diameter of the inner cylindrical portion 71 is formed to be equal to the inner diameter of the inner tube 11. The inner cylindrical portion 71 is disposed inside the inner tube 11 with its outer peripheral surface in contact with the inner peripheral surface of the inner tube 11.

[0021] The outer diameter of the outer cylindrical portion 72 is formed to be equal to the inner diameter of the second end of the outer cylinder 12. The outer cylindrical portion 72 is disposed on the second side of the inner cylinder 11 between the rod 20 and the outer cylinder 12 with its outer peripheral surface in contact with the inner peripheral surface of the outer cylinder 12.

[0022] The outer cylindrical portion 72 has an inner recess 721 formed at the second side end on the inside and recessed from a second side end face 720, which is the end face of the second side, an outer recess 722 formed at the second side end on the outside and recessed from the second side end face 720, and an outer peripheral recess 723 recessed from the outer peripheral surface.

[0023] The opening on the second side of inner recess 721 is chamfered. Outer recess 722 is recessed in a substantially cylindrical shape and has an inclined surface 724 formed so that the outer diameter of the second side end of outer cylindrical portion 72 gradually decreases toward the second side. Outer recess 722 also has a parallel surface 725 that is substantially parallel to the axial direction and extends from the second side end of inclined surface 724 toward the second side, and an orthogonal surface 726 that is perpendicular to the axial direction and extends outward from the first side end of inclined surface 724.

[0024] The outer peripheral recess 723 is formed by molding a portion of the outer peripheral surface of the outer cylindrical portion 72 into a flat surface parallel to the axial direction. The outer peripheral recess 723 is recessed over the entire axial direction. The outer peripheral recess 723 connects the outer recess 722 to a reservoir chamber R formed on the first side of the outer cylindrical portion 72. A plurality of outer peripheral recesses 723 (for example, four) are formed at equal intervals in the circumferential direction. Note that the shape of the outer peripheral recess 723 is not limited as long as the outer recess 722 and the reservoir chamber R are connected to each other. For example, the outer peripheral recess 723 may be recessed from the outer peripheral surface. Furthermore, the number of outer peripheral recesses 723 may be one.

[0025] Furthermore, a groove 727 is formed in the outer cylindrical portion 72 at the second end portion thereof. The groove 727 is recessed from the second end surface 720 and connects the inner recess 721 and the outer recess 722. The groove 727 is formed linearly extending in the radial direction. A plurality of grooves 727 are formed at equal intervals in the circumferential direction. For example, the same number of grooves 727 as the outer peripheral recesses 723 are formed, and the grooves 727 are formed so that their circumferential positions are the same as those of the outer peripheral recesses 723.

[0026] For example, the circumferential size of groove 727 is 1 / 15 to 1 / 25 of the circumferential size of second side end face 720. For example, guide case 70 configured as described above may be formed from a metal such as steel or a non-metallic material such as polytetrafluoroethylene.

[0027] [Sealing member 80] The sealing member 80 has an annular ring 81 made of a metal such as steel, and an elastic portion 90 made of a material with a low elastic modulus such as synthetic rubber. The sealing member 80 is formed by, for example, baking and bonding the elastic portion 90 to the ring 81, and the ring 81 holds the elastic portion 90.

[0028] The ring 81 is annular, and has an inner diameter larger than the outer diameter of the rod 20 and slightly smaller than the inner diameter of the second end of the outer cylinder 12. For example, the outer diameter of the ring 81 is 0.5 mm to 3 mm smaller than the inner diameter of the second end of the outer cylinder 12.

[0029] The elastic portion 90 is provided on the first side of the ring 81, has a wedge-shaped cross section, and has a seal lip portion 91 that is pressed by an annular spring to come into close contact with the entire outer circumferential surface of the rod 20. The elastic portion 90 also has a dust lip 92 that is provided on the second side of the ring 81 and comes into close contact with the entire outer circumferential surface of the rod 20 to prevent dust from entering from outside. The seal lip portion 91 and the dust lip 92 are integrally molded so as to be joined at a location inside the ring 81.

[0030] The elastic portion 90 also has an outer circumferential seal portion 93 that protrudes from the outer circumferential portion of the ring 81 all the way around to the first side. Before the seal member 80 is assembled into the outer tube 12, the outer circumferential seal portion 93 is cylindrical and has an outer diameter larger than the outer diameter of the ring 81. The inner diameter of the outer circumferential seal portion 93 is equal to or larger than the diameter of the end of the inclined surface 724 on the first side and smaller than the outer diameter of the ring 81. The outer circumferential seal portion 93 is positioned to fit into the outer recess 722 of the guide case 70 of the rod guide 60 and comes into contact with the inner circumferential surface of the outer tube 12, thereby preventing oil from leaking from a gap between the outer circumferential surface of the guide case 70 and the inner circumferential surface of the outer tube 12.

[0031] The outer seal portion 93 has a plurality of (e.g., eight) notches 931 recessed outward from the inner peripheral surface and formed at equal intervals in the circumferential direction. When viewed in the axial direction, the notches 931 are arc-shaped with a bottom 932 as an apex. The notches 931 are formed such that the bottoms 932 are positioned gradually outward from the second side to the first side, and the cross-sectional area of ​​the notches 931 cut at a plane perpendicular to the axial direction gradually increases from the second side to the first side.

[0032] The size of the notch 931 in the circumferential direction can be, for example, 1 / 60 to 1 / 100 of the size of the outer peripheral seal portion 93 in the circumferential direction.

[0033] The elastic portion 90 also has a central seal portion 94 that protrudes from the inner circumferential portion of the ring 81 around the entire circumference in a direction inclined axially outward toward the first side. The central seal portion 94 contacts the inner recess 721 of the outer cylindrical portion 72 of the guide case 70, thereby preventing oil and gas filled in the reservoir chamber R from moving inward via the flow path 75 (see FIG. 4). The central seal portion 94 and the seal lip portion 91 are integrally molded so as to be joined at a location closer to the first side than the ring 81.

[0034] The elastic portion 90 also has a connecting portion 95 that connects the outer seal portion 93 and the central seal portion 94 on the first side of the ring 81. The connecting portion 95 is molded around the entire circumference. The connecting portion 95 protrudes from the first side end surface 811 of the ring 81 by, for example, 1 mm to 5 mm.

[0035] In the seal member 80 according to this embodiment, a first side end surface 811 of the ring 81 is covered by the seal lip portion 91, the central seal portion 94, the connection portion 95, and the outer circumferential seal portion 93. On the other hand, an inner portion of a second side end surface 812 of the ring 81 is covered by the dust lip 92, and an outer portion thereof is exposed and not covered by the elastic portion 90.

[0036] When assembling the shock absorber 2, after inserting the rod guide 60 into the outer tube 12, the seal member 80 is inserted into the outer tube 12 until the elastic portion 90 covering the first side end surface 811 of the ring 81 contacts the second side end surface 720 of the guide case 70. The seal member 80 is then held to the outer tube 12 by bending the second side end of the outer tube 12 inward, a process known as roll crimping. In other words, the axial movement of the seal member 80 is restricted by the connection portion 95 of the elastic portion 90 contacting the second side end surface 720 of the outer cylindrical portion 72 of the guide case 70 and the outer periphery of the second side end surface 812 of the ring 81 contacting the inwardly bent outer tube 12. In this way, the seal member 80 is provided in the second side opening of the outer tube 12 and blocks the opening.

[0037] When the rod guide 60 and the seal member 80 are assembled, the tip end of the central seal portion 94 of the seal member 80 contacts the inner recess 721 of the guide case 70. Furthermore, the outer peripheral surface 934 of the outer peripheral seal portion 93 of the seal member 80 contacts the inner peripheral surface of the outer tube 12, and the inner peripheral surface 935 contacts the inclined surface 724 of the guide case 70. However, the tip end 933 of the outer peripheral seal portion 93 of the seal member 80 does not contact the orthogonal surface 726 of the guide case 70, and a gap is formed between the tip end 933 and the orthogonal surface 726.

[0038] 4 is a diagram showing an example of the flow path 75. The rod guide 60 and seal member 80 configured as described above form a flow path 75 that returns oil that has passed through the gap between the rod 20 and the guide 61 and reached the second side of the inner cylindrical portion 71 of the guide case 70 to the reservoir chamber R. The flow path 75 is formed by the gap between the rod guide 60 and the seal member 80 and the gap between the rod guide 60 and the outer cylinder 12. The flow path 75 has a first flow path 751 formed by the groove 727 of the outer cylindrical portion 72 and the seal member 80, and a second flow path 752 formed by the gap between the parallel surface 725 of the outer cylindrical portion 72 and the outer peripheral seal portion 93. In addition, the flow path 75 has a third flow path 753 formed by the inclined surface 724 and a notch 931 formed in the outer peripheral seal portion 93, a fourth flow path 754 formed by the tip portion 933 of the outer peripheral seal portion 93 and the orthogonal surface 726, and a fifth flow path 755 formed by the outer peripheral recess 723 and the outer tube 12.

[0039] The first flow path 751 is a flow path that moves radially from the inner recess 721. The second flow path 752 is a flow path that moves circumferentially between the parallel surface 725 of the guide case 70 and the seal member 80. The third flow path 753 is a flow path that moves in a direction inclined with respect to the axial direction between the inclined surface 724 of the guide case 70 and the seal member 80. The fourth flow path 754 is a flow path that moves circumferentially between the orthogonal surface 726 of the guide case 70 and the seal member 80 and the outer tube 12. The fifth flow path 755 is a flow path that moves axially between the outer peripheral recess 723 of the guide case 70 and the outer tube 12.

[0040] When the rod guide 60 and the seal member 80 are assembled, if the circumferential positions of the groove 727 and the outer peripheral recess 723 of the guide case 70 coincide with the circumferential position of the notch 931 formed in the outer peripheral seal portion 93 of the seal member 80, the oil may move through the first flow path 751 and then flow into the third flow path 753 without moving circumferentially through the second flow path 752. Furthermore, after moving through the third flow path 753, the oil may flow into the fifth flow path 755 without moving circumferentially through the fourth flow path 754.

[0041] As described above, the shock absorber 2 includes the inner cylinder 11 in which oil as an example of a working fluid is sealed, the outer cylinder 12 provided outside the outer periphery of the inner cylinder 11 and forming a reservoir chamber R for storing oil between the inner cylinder 11 and the outer cylinder 12, and the piston portion 30 that partitions a space formed within the inner cylinder 11. The shock absorber 2 also includes the rod 20 that holds the piston portion 30 at a first end as an example of one end and has a second end as an example of the other end that protrudes from an opening of the outer cylinder 12, and the rod guide 60 that slidably supports the rod 20 and has an outer periphery that contacts the inner surface of the outer cylinder 12. The shock absorber 2 also includes the seal member 80 that is provided on a side closer to the opening than the rod guide 60 in the axial direction of the rod 20 to form a contact portion 100 with the rod guide 60, and that has: a seal lip portion 91 as an example of a first seal portion that seals between the rod 20 and the outer periphery seal portion 93 as an example of a second seal portion that seals between the rod 20 and the inner surface of the outer cylinder 12. A contact portion 100 is formed between the second side end surface 720 of the outer cylindrical portion 72 of the rod guide 60 and the connecting portion 95 of the elastic portion 90 of the seal member 80 (see FIG. 2 ). The rod guide 60 has an inclined surface 724 as an example of a pressed portion, which is provided at the end of the outer periphery on the opening side and against which an inner portion (e.g., inner periphery surface 935) of a portion (e.g., outer periphery surface 934) of the outer periphery seal portion 93 that contacts the inner surface of the outer tube 12 is pressed. The rod guide 60 also has an outer periphery recess 723 that forms a fifth flow path 755 as an example of an outer periphery flow path that returns oil to the reservoir chamber R between the outer periphery surface and the inner surface of the outer tube 12. The inner periphery surface 935 that is pressed against the inclined surface 724 of the outer periphery seal portion 93 has a notch 931 that forms a third flow path 753 as an example of a relay flow path that directs oil that has passed through a gap between the seal lip portion 91 and the rod 20 and reached the opening side toward the fifth flow path 755.

[0042] In the shock absorber 2 configured as described above, the gap between the rod guide 60 and the seal member 80 forms a flow path 75 that returns the hydraulic oil that has passed through the gap between the rod 20 and the guide 61 and reached the second side of the inner cylindrical portion 71 of the guide case 70 to the reservoir chamber R. Furthermore, in the guide case 70 of the rod guide 60, the communication path connecting the inner recess 721 and the reservoir chamber R is not formed by, for example, a hole penetrating the guide case 70 in the axial direction. This allows the guide case 70 to be easily molded. For example, if the axially penetrating hole is molded using a die, a protrusion for molding the hole is required on at least one of the first and second molds that divide the guide case 70 in the axial direction. Alternatively, if the axially penetrating hole is molded by cutting, a cutting process is required. In contrast, in the guide case 70, the communication path connecting the inner recess 721 and the reservoir chamber R is not formed by a hole penetrating the interior of the guide case 70, allowing the guide case 70 to be easily molded.

[0043] Furthermore, since the rod guide 60 has an inclined surface 724 against which the inner peripheral surface 935 of the outer peripheral seal portion 93 is pressed, the outer peripheral seal portion 93 is less likely to deform inward, and therefore the contact pressure between the outer peripheral surface 934 of the outer peripheral seal portion 93 and the inner peripheral surface of the outer tube 12 is high. This prevents oil from leaking from the gap between the outer peripheral seal portion 93 and the inner peripheral surface of the outer tube 12.

[0044] Here, a groove 727 that connects the inside and outside of the contact portion 100 is formed in the rod guide 60. This makes it possible to form a flow path 75 by the gap between the rod guide 60 and the seal member 80. Furthermore, a plurality of grooves 727 that connect the inside and outside of the contact portion 100 are formed in the rod guide 60, and the number of notches 931 is greater than the number of grooves 727. This allows the oil that has passed through the grooves 727 to be quickly returned to the reservoir chamber R.

[0045] Furthermore, the rod guide 60 communicates with the groove 727 and forms a second flow path 752, which is an example of a circumferential flow path through which oil moves circumferentially, between the rod guide 60 and the seal member 80. This allows the oil that has passed through the groove 727 to be returned to the reservoir chamber R even if the circumferential position of the groove 727 does not match the circumferential position of the notch 931.

[0046] Furthermore, the axial tip 933 of the outer circumferential seal portion 93 is not pressed against the rod guide 60. As a result, a gap is formed between the tip 933 and the rod guide 60, so that even if the circumferential position of the notch 931 does not match the circumferential position of the outer circumferential recess 723 of the guide case 70, the oil that has passed through the groove 727 can be returned to the reservoir chamber R.

[0047] Furthermore, the seal member 80 has a central seal portion 94 as an example of a third seal portion between the seal lip portion 91 and the outer circumferential seal portion 93, which allows oil to flow from the seal lip portion 91 toward the outer circumferential seal portion 93, while suppressing oil from flowing from the outer circumferential seal portion 93 toward the seal lip portion 91. This makes it possible to suppress oil from flowing into the inner cylinder 11 from the reservoir chamber R through the gap between the rod guide 60 and the seal member 80.

[0048] (Modification of the cutout 931) The shape of the cutout 931 formed in the outer circumferential seal portion 93, when cut along a plane perpendicular to the axial direction, is an arc shape with the bottom 932 as the apex, but is not particularly limited to this shape. Figure 5 is a diagram showing an example of a modification of the cutout 931. The shape of the cutout 931, when cut along a plane perpendicular to the axial direction, may be a rectangle. Because connection portions 936 between both circumferential ends of the cutout 931 and the inner circumferential surface 935 are approximately right angles, the cutout 931 is unlikely to be crushed even if the inner circumferential surface 935 is pressed against the inclined surface 724 of the guide case 70, and the third flow path 753 is therefore formed with high accuracy.

[0049] Furthermore, a protrusion 938 protruding inward from the bottom surface 937 may be provided in the circumferential center of the notch 931. Even if the shape of the notch 931 when cut along a plane perpendicular to the axial direction is rectangular and the circumferential size of the notch 931 is large, the protrusion 938 is pressed against the inclined surface 724 of the guide case 70, making the notch 931 less likely to be crushed. As a result, the third flow path 753 is formed with high reliability.

[0050] Second Embodiment Fig. 6 is a diagram showing an example of a cross section of a rod guide 260 and a seal member 280 according to the second embodiment. The rod guide 260 according to the second embodiment differs from the rod guide 60 according to the first embodiment in that it has a guide case 270 that corresponds to the guide case 70. Furthermore, the seal member 280 according to the second embodiment differs from the seal member 80 according to the first embodiment in that it has an elastic portion 290 that corresponds to the elastic portion 90. Differences from the first embodiment will be described below. The same components in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0051] In the first embodiment, depending on the position of the seal member 80 relative to the guide case 70, there may not be any location where the circumferential position of the groove 727 of the outer cylindrical portion 72 coincides with the circumferential position of the notch 931 of the outer peripheral seal portion 93. In contrast, the guide case 270 and the seal member 280 according to the second embodiment are configured so that there are always four or more locations where the circumferential position of the groove 727 of the outer cylindrical portion 72 that constitutes the first flow path 751 coincides with the circumferential position of the notch 931 of the outer peripheral seal portion 93.

[0052] That is, guide case 270 differs from guide case 70 according to the first embodiment in that seven grooves 727 are formed at equal intervals in the circumferential direction. Furthermore, seal member 280 differs from seal member 80 according to the first embodiment in that twelve notches 931 are formed at equal intervals in the circumferential direction. As a result, there are always four or more locations where the circumferential position of groove 727 coincides with the circumferential position of notch 931. Figure 6 shows an embodiment in which there are five locations (circled in the figure) where the circumferential position of groove 727 coincides with the circumferential position of notch 931.

[0053] According to the rod guide 260 and sealing member 280 of the second embodiment configured as described above, oil that has moved to the second side through the gap between the rod 20 and the guide 61 can be quickly returned to the reservoir chamber R.

[0054] 6, seven grooves 727 are formed in the guide case 270, and twelve notches 931 are formed in the seal member 280, but these numbers are not particularly limited. It is preferable that either the number of grooves 727 or the number of notches 931 is an even number, and the other is an odd number. This makes it easier for the circumferential positions of the grooves 727 and the circumferential positions of the notches 931 to coincide. However, it is desirable that the number of notches 931 is greater than the number of grooves 727. This is because oil that has moved to the second side through the gap between the rod 20 and the guide 61 can be quickly returned to the reservoir chamber R.

[0055] <Third embodiment> Figure 7 is a perspective view showing an example of the schematic configuration of a rod guide 360 ​​and a seal member 380 according to a third embodiment. The rod guide 360 ​​according to the third embodiment differs from the rod guide 60 according to the first embodiment in that it has a guide case 370 that corresponds to the guide case 70. Furthermore, the seal member 380 according to the third embodiment differs from the seal member 80 according to the first embodiment in that it has an elastic portion 390 that corresponds to the elastic portion 90. Differences from the first embodiment will be described below. The same components in the first and third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0056] In the guide case 370 and elastic portion 390 of the third embodiment, the circumferential position of the groove 727 of the outer cylindrical portion 72 that constitutes the first flow path 751 and the circumferential position of the notch 931 of the outer sealing portion 93 are configured to coincide with a high degree of accuracy.

[0057] That is, in the guide case 370, a fitting recess 371 is formed between the groove 727 and the outer circumferential recess 723, recessed from the parallel surface 725, the inclined surface 724, and the orthogonal surface 726. The circumferential size of the fitting recess 371 is larger than the circumferential size of the groove 727 and smaller than the circumferential size of the outer circumferential recess 723.

[0058] Furthermore, the elastic portion 390 is provided with protrusions 394 that protrude inward from the inner peripheral surface 935 at both circumferential ends of the notch 931 in the outer peripheral seal portion 393 that corresponds to the outer peripheral seal portion 93. The circumferential size between the protrusions 394 provided at both circumferential ends of the notch 931 is smaller than the circumferential size of the fitting recess 371 of the guide case 370.

[0059] When the seal member 380 is disposed on the second side of the rod guide 360, the protrusions 394 provided on both circumferential ends of the notch 931 are fitted into the fitting recess 371 of the guide case 370. This ensures that the circumferential position of the groove 727 of the outer cylindrical portion 72 that constitutes the first flow path 751 matches with the circumferential position of the notch 931 of the outer peripheral seal portion 393. As a result, oil that has passed through the groove 727 can be quickly returned to the reservoir chamber R via the notch 931 and the outer peripheral recess 723 without being moved circumferentially.

[0060] In the guide case 370 and the elastic portion 390 according to the third embodiment, the circumferential positions of the grooves 727 and the cutouts 931 coincide with each other with a high degree of accuracy, and therefore the number of cutouts 931 may be the same as the number of grooves 727. Furthermore, the number of grooves 727 and cutouts 931 may be fewer than the number in the first embodiment. For example, the number of grooves 727 and cutouts 931 may be two each.

[0061] <Fourth embodiment> Fig. 8 is a diagram showing an example of a schematic configuration of a seal member 480 according to a fourth embodiment. The seal member 480 according to the fourth embodiment differs from the seal member 80 according to the first embodiment in that a ring 481 corresponding to the ring 81 and an elastic portion 490 corresponding to the elastic portion 90 are provided. Differences from the first embodiment will be described below. The same reference numerals are used for the same components in the first and fourth embodiments, and detailed description thereof will be omitted.

[0062] The ring 481 differs from the ring 81 according to the first embodiment in that the first side end surface 811 is configured to contact the second side end surface 720 of the guide case 70. In other words, the ring 481 has a plurality of (eight, for example) recesses 482 formed at the radial center thereof, recessed from the first side end surface 811 toward the second side, and spaced at equal intervals in the circumferential direction.

[0063] The elastic portion 490 differs from the elastic portion 90 according to the first embodiment in that the connecting portion 495 corresponds to the connecting portion 95 that connects the outer periphery seal portion 93 and the central seal portion 94. The connecting portion 495 is provided only in the area where the recess 482 is formed in the ring 481, and connects the outer periphery seal portion 93 and the central seal portion 94 only in the area where the recess 482 is formed.

[0064] That is, in the seal member 480 according to the fourth embodiment, the first side end surface 811, where the recess 482 is not formed, is exposed without being covered by the elastic portion 490. Then, when the rod guide 60 and the seal member 480 are assembled, the first side end surface 811 contacts the second side end surface 720 of the guide case 70. This prevents a decrease in the axial holding force of the second side end portion of the outer tube 12, which is bent inward, due to the presence of an elastic body between the ring 481 of the seal member 480 and the guide case 70.

[0065] Fifth Embodiment FIG. 9 is a perspective view of a rod guide 560 according to a fifth embodiment, as viewed from the second side, and an example of a perspective view of a seal member 580 according to the fifth embodiment, as viewed from the first side. FIG. 10 is a view showing an example of a cross section of the rod guide 560 and the seal member 580 according to the fifth embodiment. The rod guide 560 according to the fifth embodiment differs from the rod guide 60 according to the first embodiment in that it has a guide case 570 corresponding to the guide case 70. Furthermore, the seal member 580 according to the fifth embodiment differs from the seal member 80 according to the first embodiment in that it has an elastic portion 590 corresponding to the elastic portion 90. Differences from the first embodiment will be described below. The same components in the first and fifth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0066] The guide case 570 differs from the guide case 70 according to the first embodiment in that it does not have a groove 727. The elastic portion 590 differs from the elastic portion 90 according to the first embodiment in that it has a connection portion 595 that corresponds to the connection portion 95. The connection portion 595 has a recess 596 recessed from the end face on the first side, at a location where the cutout 931 is formed in the outer circumferential seal portion 93. The recess 596 is formed to be continuous with the cutout 931.

[0067] In the guide case 570 and elastic portion 590 according to the fifth embodiment, when the elastic portion 590 is assembled so that the first end surface of the connecting portion 595 contacts the second end surface 720 of the outer cylindrical portion 72 of the guide case 70, oil that passes through the gap between the rod 20 and the guide 61 and reaches the second side of the inner cylindrical portion 71 of the guide case 570 flows through the recess 596 of the connecting portion 595 into the notch 931 and returns to the reservoir chamber R. In other words, the first flow path 751 is formed by the recess 596 of the connecting portion 595.

[0068] According to the rod guide 560 and seal member 580 of the fifth embodiment, it is not necessary to form the groove 727 in the guide case 570, and therefore it is possible to simplify the configuration of the mold used to mold the guide case 570. Furthermore, oil that has passed through the recess 596 of the connection portion 595 can be quickly returned to the reservoir chamber R via the notch 931 and the outer peripheral recess 723 without being moved in the circumferential direction.

[0069] 1...Suspension device, 2...Shock absorber, 3...Coil spring (an example of a spring), 10...Cylinder portion, 11...Inner cylinder, 12...Outer cylinder, 20...Rod, 30...Piston portion, 60...Rod guide, 75...Flow path, 80...Sealing member, 91...Seal lip portion (an example of a first sealing portion), 93...Outer peripheral sealing portion (an example of a second sealing portion), 94...Central sealing portion, 95...Connection portion, 100...Contact portion, 722...Outer recess, 723...Outer peripheral recess, 724...Inclined surface (an example of a pressed portion), 726...Orthogonal surface, 727...Groove, 751...First flow path, 752...Second flow path, 753...Third flow path, 754...Fourth flow path, 755...Fifth flow path, 931...Notch, 933...Tip portion, 938...Protrusion, R...Reservoir chamber

Claims

1. an inner cylinder in which a working fluid is sealed; an outer cylinder provided outside the outer periphery of the inner cylinder and defining a reservoir chamber for storing the working fluid between the outer cylinder and the inner cylinder; a piston portion that defines a space formed in the inner cylinder; a rod having one end that holds the piston portion and the other end that protrudes from the opening of the outer cylinder; a rod guide that slidably supports the rod and whose outer periphery contacts the inner surface of the outer cylinder; a seal member provided on the opening side of the rod guide in the axial direction of the rod so as to form a contact portion with the rod guide, the seal member having a first seal portion for sealing against the rod and a second seal portion for sealing against the inner surface of the outer cylinder; Equipped with the rod guide has a pressed portion provided at an end of the outer circumferential portion on the opening side, against which an inner portion of a portion of the second seal portion that contacts the inner surface of the outer cylinder is pressed, and an outer circumferential recess that is recessed from the outer circumferential surface and forms an outer circumferential flow path between the outer circumferential surface and the inner surface of the outer cylinder, for returning the working fluid to the reservoir chamber; A notch is formed in a portion of the second seal portion that is pressed against the pressed portion, forming a relay flow path that allows the working fluid that has passed through a gap between the rod guide and the rod and reached the opening side to flow toward the outer circumferential flow path. Buffer device.

2. The rod guide has a groove formed therein that communicates the inside and outside of the contact portion. The shock absorber according to claim 1 .

3. The rod guide has a plurality of grooves formed therein, the grooves communicating with the inside and outside of the contact portion, The number of the notches is greater than the number of the grooves. The shock absorber according to claim 1 .

4. One of the number of the grooves and the number of the notches is an even number, and the other is an odd number. The shock absorber according to claim 3.

5. Four or more of the notches communicate with the plurality of grooves. The shock absorber according to claim 4.

6. The rod guide communicates with the groove and forms a circumferential flow path between the rod guide and the seal member, through which the working fluid moves in a circumferential direction. The shock absorber according to claim 2 .

7. The seal member has a third seal portion between the first seal portion and the second seal portion, which allows the working fluid to flow from the first seal portion toward the second seal portion and prevents the working fluid from flowing from the second seal portion toward the first seal portion. The shock absorber according to claim 1 .

8. The axial tip end portion of the second seal portion is not pressed against the rod guide. The shock absorber according to claim 1 .

9. The notch has a rectangular shape when viewed in the axial direction. The shock absorber according to claim 1 .

10. The notch is provided with a protruding portion that protrudes from a bottom surface toward the rod guide. The shock absorber according to claim 9.

11. A shock absorber according to any one of claims 1 to 10; a spring disposed around the shock absorber; A suspension device comprising: