Buffer device, 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

Technical Field

[0001] The present invention relates to a shock absorber and a suspension device.

Background Art

[0002] For example, the shock absorber of 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 pivotally supports a rod that is movably inserted into the cylinder. Below the cylinder, a piston connected to the lower end of the rod is slidably inserted, and this piston partitions a rod-side chamber filled with hydraulic oil and a piston-side chamber in the cylinder. Further, a reservoir filled with gas and hydraulic oil is formed between the cylinder and the outer cylinder. Above this rod guide, a seal member including an annular insert metal, an inner peripheral seal held on the inner periphery of the insert metal and slidably contacting the outer periphery of the rod, and an outer peripheral seal held on the outer periphery of the insert metal and closely contacting the outer peripheries of the rod guide and the outer cylinder is laminated. A cylindrical slide bearing is attached to the inner periphery of the guide portion of the rod guide, and the rod is slidably inserted into this slide bearing. Further, the rod guide includes a recess provided on the inner peripheral side and a communication hole that communicates from this recess to a desired surface of the flange reservoir, and hydraulic oil that has passed between the rod and the slide bearing can be returned to the reservoir through the communication hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the shock absorber described in Patent Document 1, the rod guide has a communication hole that connects a recess on the inner circumference to the reservoir, which is formed by a hole that penetrates a part of the rod guide. Therefore, there was room for improvement in terms of easily forming the rod guide. For example, if the through hole is formed using a mold, the structure of the mold becomes complex, and the cost of the mold becomes high. Also, if the through hole is formed by cutting, a cutting process is required. The present invention aims to provide a shock absorber and the like that can be used to easily manufacture rod guides. [Means for solving the problem]

[0005] The present invention, completed with this objective in mind, comprises an inner cylinder in which a working fluid is sealed; an outer cylinder provided on the outer side of the outer circumference of the inner cylinder and forming a reservoir chamber for storing the working fluid between itself and the inner cylinder; a piston portion that partitions the 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 circumference contacts the inner surface of the outer cylinder; a first seal portion 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 and seals the space between itself and the rod; and The rod guide is a buffer device comprising a sealing member having a second sealing portion that seals the space between the rod and the inner surface of the outer cylinder, the rod guide having a pressing portion provided at the end of the outer circumference on the opening side, against which the inner portion of the portion of the second sealing portion that contacts the inner surface of the outer cylinder is pressed, and an outer recess recess recessed from the outer surface that forms an outer channel for returning the working fluid to the reservoir chamber between itself and the inner surface of the outer cylinder, and a notch formed in the portion of the second sealing portion that is pressed against the pressing portion, which forms a relay channel for flowing the working fluid that has passed through the gap between the first sealing portion and the rod to the opening side toward the outer channel. In this case, the rod guide may have a groove formed therein that connects the inner and outer sides of the contact portion. Furthermore, the rod guide has a plurality of grooves that connect the inside and outside of the contact portion, and the number of notches may be greater than the number of grooves. Furthermore, either the number of grooves or the number of notches may be even, while the other is odd. Furthermore, four or more of the notches may be connected to multiple grooves. Furthermore, the rod guide may communicate with the groove and form a circumferential flow path between itself and the sealing member through which the working fluid moves in the circumferential direction. Furthermore, the sealing member may have a third sealing portion between the first sealing portion and the second sealing portion that allows the working fluid to flow from the first sealing portion to the second sealing portion, while suppressing the flow of the working fluid from the second sealing portion to the first sealing portion. Furthermore, the axial tip of the second seal portion does not need to 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 projection that extends from the bottom surface toward the rod guide. From another perspective, the present invention is a suspension system comprising the above-described shock absorber and a spring arranged around the shock absorber. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a shock absorber and the like that can be used to easily manufacture rod guides. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a schematic configuration of a suspension system according to the first embodiment. [Figure 2] This is an enlarged view of part II of Figure 1. [Figure 3] This figure shows an example of a perspective view of a rod guide and sealing member. [Figure 4]This is a diagram showing an example of a flow path. [Figure 5] This figure shows an example of a modified notch. [Figure 6] This figure shows an example of a cross-section of a rod guide and sealing member according to the second embodiment. [Figure 7] This is a perspective view showing an example of the schematic configuration of a rod guide and sealing member according to the third embodiment. [Figure 8] This figure shows an example of a general configuration of a sealing member according to the fourth embodiment. [Figure 9] This figure shows an example of a perspective view of the rod guide according to the fifth embodiment as seen from the second side, and an example of a perspective view of the sealing member according to the fifth embodiment as seen from the first side. [Figure 10] This figure shows an example of a cross-section of a rod guide and sealing member according to the fifth embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings. <First Embodiment> Figure 1 is a diagram showing an example of a schematic configuration of the suspension device 1 according to the first embodiment. Figure 2 is an enlarged view of part II of Figure 1. Figure 3 shows an example of a perspective view of the rod guide 60 and the sealing member 80. The suspension system 1 is a suspension used in four-wheeled vehicles such as passenger cars, and as shown in Figure 1, it comprises a hydraulic shock absorber 2 and a coil spring 3 positioned outside the shock absorber 2. The suspension system 1 also comprises a lower spring seat 4 that supports the first axial end (lower side in Figure 1) of the rod 20, which will be described later, and an upper spring seat 5 that supports the second axial end (upper side in Figure 1) of the rod 20.

[0009] The suspension device 1 also includes a vehicle body side bracket 6 that is attached to the second side end in the axial direction of the rod 20 for attaching the suspension device 1 to the vehicle, and a wheel side bracket 7 that is fixed to the first side end in the axial direction of the rod 20 in the cylinder part 10 described later for attaching the suspension device 1 to the wheel. The suspension device 1 also includes a dust cover 8 that covers at least a part of the cylinder part 10 and the rod 20.

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

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

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

[0013] Further, the cylinder part 10 includes a rod guide 60 that supports the rod 20 movably, a bump stopper cap 15 attached to the end on the second side of the outer cylinder 12, and a seal member 80 that prevents oil leakage in the cylinder part 10 and entry of foreign matter into the cylinder part 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 part 30 on the first side. Also, the rod 20 is connected to, for example, a vehicle body via a vehicle body side bracket 6 on the second side.

[0015] The piston part 30 includes a piston 31, a valve group 32 that closes the end on the first side in a part of the plurality of oil passages formed in the piston 31, and a valve group 33 that closes the end on the second side in a part 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 filled with oil in the inner cylinder 11 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] As shown in FIG. 1, the bottom part 40 includes a valve body 41 having a plurality of oil passages penetrating in the axial direction, a valve 42 provided on the first side of the valve body 41, and a valve 43 provided on the second side of the valve body 41. The valve body 41 of the bottom part 40 divides the first oil chamber Y1 and the 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 to be slightly larger than the outer diameter of the rod 20 inserted inside it. 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. Since the inner surface of the guide 61 contacts the outer surface of the rod 20, it is molded from a material with better wear resistance than the guide case 70.

[0019] The guide case 70 has an inner cylindrical portion 71 provided on the inside and an 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 so that the outer circumferential surface of the second side portion of the inner cylindrical portion 71 and the inner circumferential surface of the first side portion of the outer cylindrical portion 72 are joined together.

[0020] A guide 61 is fitted inside the inner cylindrical portion 71. The outer diameter of the inner cylindrical portion 71 is molded to be equal to the inner diameter of the inner cylinder 11. The inner cylindrical portion 71 is positioned inside the inner cylinder 11 with its outer circumferential surface in contact with the inner circumferential surface of the inner cylinder 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 positioned between the rod 20 and the outer cylinder 12 on the second side of the inner cylinder 11, with its outer circumferential surface in contact with the inner circumferential surface of the outer cylinder 12.

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

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

[0024] The outer peripheral recess 723 is formed by shaping a portion of the outer peripheral surface of the outer cylindrical portion 72 into a plane parallel to the axial direction. The outer peripheral recess 723 is recessed over its entire axial length. The outer peripheral recess 723 connects the outer recess 722 to the reservoir chamber R formed on the first side of the outer cylindrical portion 72. Multiple outer peripheral recesses 723 are formed at equal intervals in the circumferential direction (for example, four). The shape of the outer peripheral recess 723 is not limited as long as the outer recess 722 and the reservoir chamber R are in communication. For example, the outer peripheral recess 723 may be recessed in a concave shape from the outer peripheral surface. Also, there may be only one outer peripheral recess 723.

[0025] Furthermore, the outer cylindrical portion 72 has a groove 727 formed at the second end, recessed from the second end face 720, connecting the inner recess 721 and the outer recess 722. The groove 727 is formed in a linear shape extending in the radial direction. Multiple grooves 727 are formed at equal intervals in the circumferential direction. For example, the same number of grooves 727 are formed as the outer circumferential recesses 723, and their circumferential positions are the same as those of the outer circumferential recesses 723.

[0026] For example, the circumferential size of the groove 727 can be exemplified as being 1 / 15 to 1 / 25 of the circumferential size of the second side end face 720. As described above, the guide case 70 can be exemplified by being molded from metals such as steel or non-metallic materials such as polytetrafluoroethylene.

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

[0028] The ring 81 is annular in shape, with an inner diameter larger than the outer diameter of the rod 20 and an outer diameter 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 includes a seal lip portion 91 that is pressed by an annular spring and adheres tightly to the entire circumference of the outer surface of the rod 20. The elastic portion 90 is also provided on the second side of the ring 81 and includes a dust lip portion 92 that adheres tightly to the entire circumference of the outer surface of the rod 20 to suppress the intrusion of dust from the outside. The seal lip portion 91 and the dust lip portion 92 are integrally molded so as to be joined in the portion inside the ring 81.

[0030] Furthermore, the elastic portion 90 has an outer peripheral sealing portion 93 that protrudes to the first side from the outer circumference of the ring 81 over its entire circumference. Before the sealing member 80 is assembled into the outer cylinder 12, the outer peripheral sealing portion 93 is cylindrical and its outer diameter is larger than the outer diameter of the ring 81. The inner diameter of the outer peripheral sealing portion 93 is greater than or equal to the diameter of the first end on the inclined surface 724 and smaller than the outer diameter of the ring 81. The outer peripheral sealing portion 93 is positioned to fit into the outer recess 722 of the guide case 70 of the rod guide 60 and contacts the inner circumferential surface of the outer cylinder 12, thereby suppressing oil leakage from the gap between the outer circumferential surface of the guide case 70 and the inner circumferential surface of the outer cylinder 12.

[0031] The outer circumferential sealing portion 93 has multiple (for example, 8) notches 931 formed at equal intervals in the circumferential direction, recessed outward from the inner circumferential surface. When viewed in the axial direction, the notches 931 are arc-shaped with the bottom portion 932 as the apex. Furthermore, the notches 931 are formed such that the bottom portion 932 gradually moves outward from the second side to the first side, and the cross-sectional area when the notch 931 is cut by a plane perpendicular to the axial direction gradually increases from the second side to the first side.

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

[0033] Furthermore, the elastic portion 90 has a central seal portion 94 that protrudes from the inner circumference of the ring 81 in a direction that is axially inclined to the first side and outward over its entire circumference. The central seal portion 94 contacts the inner recess 721 of the outer cylindrical portion 72 of the guide case 70, thereby preventing oil or gas filled in the reservoir chamber R from moving inward via the flow path 75 (see Figure 4). The central seal portion 94 and the seal lip portion 91 are integrally molded to be joined at a point on the first side of the ring 81.

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

[0035] In the sealing member 80 according to this embodiment, the first side end face 811 of the ring 81 is covered by the sealing lip portion 91, the central sealing portion 94, the connecting portion 95, and the outer peripheral sealing portion 93. On the other hand, the second side end face 812 of the ring 81 has its inner portion covered by the dust lip 92, while its outer portion 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 cylinder 12, the sealing member 80 is inserted into the outer cylinder 12 until the elastic portion 90 covering the first end face 811 of the ring 81 contacts the second end face 720 of the guide case 70. The sealing member 80 is then held in place by a so-called roll crimp, in which the second end of the outer cylinder 12 is bent inward. In other words, the axial movement of the sealing member 80 is restricted because the connecting portion 95 of the elastic portion 90 contacts the second end face 720 of the outer cylindrical portion 72 of the guide case 70, and the outer circumference of the second end face 812 of the ring 81 contacts the inwardly bent outer cylinder 12. In this way, the sealing member 80 is provided at the second opening in the outer cylinder 12 and closes the opening.

[0037] With the rod guide 60 and the sealing member 80 assembled, the tip of the central sealing portion 94 of the sealing member 80 contacts the inner recess 721 of the guide case 70. The outer peripheral sealing portion 93 of the sealing member 80 has its outer peripheral surface 934 in contact with the inner peripheral surface of the outer cylinder 12, and its inner peripheral surface 935 in contact with the inclined surface 724 of the guide case 70. However, the tip 933 of the outer peripheral sealing portion 93 of the sealing member 80 does not contact the orthogonal surface 726 of the guide case 70, and a gap is formed between the tip 933 and the orthogonal surface 726.

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

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

[0040] Furthermore, 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 flow into the third passage 753 after moving through the first passage 751, without moving circumferentially through the second passage 752. Also, after moving through the third passage 753, the oil may flow into the fifth passage 755 without moving circumferentially through the fourth passage 754.

[0041] As described above, the shock absorber 2 comprises an inner cylinder 11 in which oil, as an example of a working fluid, is sealed; an outer cylinder 12 provided on the outer circumference of the inner cylinder 11 and forming a reservoir chamber R for storing oil between itself and the inner cylinder 11; and a piston portion 30 that partitions the space formed inside the inner cylinder 11. The shock absorber 2 also comprises a rod 20, with a first end (as an example of one end) holding the piston portion 30 and a second end (as an example of the other end) protruding from the opening of the outer cylinder 12; and a rod guide 60 that slidably supports the rod 20 and whose outer circumference contacts the inner surface of the outer cylinder 12. The shock absorber 2 also comprises a sealing member 80 provided on the opening side of the rod guide 60 in the axial direction of the rod 20 so as to form a contact portion 100 with the rod guide 60, and having a sealing lip portion 91 as an example of a first sealing portion that seals the space between itself and the rod 20, and an outer peripheral sealing portion 93 as an example of a second sealing portion that seals the space between itself and the inner surface of the outer cylinder 12. A contact portion 100 is formed by the second side end face 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 Figure 2). The rod guide 60 has an inclined surface 724 at the end on the opening side of the outer circumference, which is an example of a pressed portion against which the inner portion (e.g., inner circumference 935) of the portion (e.g., outer circumference 934) of the outer circumference seal portion 93 that contacts the inner surface of the outer cylinder 12 is pressed. The rod guide 60 also has an outer circumference recess 723 between the outer circumference and the inner surface of the recessed outer cylinder 12, which forms a fifth flow path 755 as an example of an outer circumference flow path that returns oil to the reservoir chamber R. The inner circumference 935 of the outer circumference seal portion 93, which is pressed against the inclined surface 724, has a notch 931 formed therein, which forms a third flow path 753 as an example of a relay flow path that directs oil that has passed through the gap between the seal lip portion 91 and the rod 20 to the opening side toward the fifth flow path 755.

[0042] In the buffer device 2 configured as described above, a passage 75 is formed by the gap between the rod guide 60 and the sealing member 80, which returns the hydraulic fluid that has passed through the gap between the rod 20 and the guide 61 to the second side of the inner cylindrical portion 71 of the guide case 70 back to the reservoir chamber R. Furthermore, the guide case 70 of the rod guide 60 does not have a connecting passage between the inner recess 721 and the reservoir chamber R, which is formed by a hole that penetrates the guide case 70, for example, in the axial direction. Therefore, the guide case 70 can be easily molded. In other words, for example, when forming a hole that penetrates in the axial direction using a mold, a projection for forming the through-hole is required in at least one of the first side mold and the second side mold that divides the mold in the axial direction. Alternatively, when forming a hole that penetrates in the axial direction by cutting, a cutting process is required. In contrast, in the guide case 70, since the connecting passage between the inner recess 721 and the reservoir chamber R is not formed by a hole that penetrates the inside of the guide case 70, the guide case 70 can be easily molded.

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

[0044] Here, the rod guide 60 has a groove 727 that connects the inside and outside of the contact portion 100. This makes it possible to form a flow path 75 in the gap between the rod guide 60 and the sealing member 80. Furthermore, the rod guide 60 has multiple grooves 727 that connect the inside and outside of the contact portion 100, 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 between itself and the sealing member 80, which is an example of a circumferential flow path through which oil moves in the circumferential direction. This allows the oil that has passed through the groove 727 to be returned to the reservoir chamber R, even if the circumferential position in the groove 727 and the circumferential position in the notch 931 do not coincide.

[0046] Furthermore, the axial tip 933 of the outer peripheral 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 and the circumferential position of the outer peripheral recess 723 of the guide case 70 do not coincide, the oil that has passed through the groove 727 can be returned to the reservoir chamber R.

[0047] Furthermore, the sealing member 80 has a central sealing portion 94, which is an example of a third sealing portion, between the sealing lip portion 91 and the outer peripheral sealing portion 93. This allows oil to flow from the sealing lip portion 91 to the outer peripheral sealing portion 93, while suppressing the flow of oil from the outer peripheral sealing portion 93 to the sealing lip portion 91. This prevents oil from flowing from the reservoir chamber R into the inner cylinder 11 through the gap between the rod guide 60 and the sealing member 80.

[0048] (Variation of notch 931) The shape of the notch 931 formed in the outer peripheral seal portion 93, when cut by a plane perpendicular to the axial direction, is an arc shape with the bottom portion 932 as its apex, but is not limited to this shape. Figure 5 shows an example of a modified notch 931. The notch 931 may have a rectangular shape when cut by a plane perpendicular to the axial direction. Because the connection points 936 between the circumferential ends of the notch 931 and the inner circumferential surface 935 are nearly right angles, the notch 931 is less likely to collapse even when the inner circumferential surface 935 is pressed against the inclined surface 724 of the guide case 70, thus the third flow channel 753 is formed with high accuracy.

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

[0050] <Second Embodiment> Figure 6 shows an example of a cross-section of the rod guide 260 and sealing 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 different guide case 270, which corresponds to the guide case 70. Also, the sealing member 280 according to the second embodiment differs from the sealing member 80 according to the first embodiment in that it has an elastic part 290, which corresponds to the elastic part 90. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and second embodiments, and their detailed descriptions will be omitted.

[0051] In the first embodiment, depending on the position of the sealing member 80 relative to the guide case 70, there may be no location where the circumferential position in the groove 727 of the outer cylindrical portion 72 coincides with the circumferential position in the notch 931 of the outer sealing portion 93. In contrast, the guide case 270 and sealing member 280 according to the second embodiment are configured such that there are always four or more locations where the circumferential position in the groove 727 of the outer cylindrical portion 72 constituting the first flow path 751 coincides with the circumferential position in the notch 931 of the outer sealing portion 93.

[0052] In other words, the guide case 270 differs from the guide case 70 according to the first embodiment in that it has seven grooves 727 formed at equal intervals in the circumferential direction. Also, the sealing member 280 differs from the sealing member 80 according to the first embodiment in that it has twelve notches 931 formed at equal intervals in the circumferential direction. As a result, there are always at least four locations where the circumferential position of the grooves 727 coincides with the circumferential position of the notches 931. Figure 6 shows an embodiment in which there are five locations (circled in the figure) where the circumferential position of the grooves 727 coincides with the circumferential position of the notches 931.

[0053] With the rod guide 260 and sealing member 280 configured as described above according to the second embodiment, the 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] In the example shown in Figure 6, the guide case 270 has 7 grooves 727 and the seal member 280 has 12 notches 931, but the number is not limited to these. It is preferable that one of the number of grooves 727 and the number of notches 931 be even and the other odd. 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 be greater than the number of grooves 727. This is because the 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 the rod guide 360 ​​and sealing member 380 according to the 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 different guide case 370, which corresponds to the guide case 70. Also, the sealing member 380 according to the third embodiment differs from the sealing member 80 according to the first embodiment in that it has a different elastic part 390, which corresponds to the elastic part 90. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and third embodiments, and their detailed descriptions will be omitted.

[0056] In the guide case 370 and elastic portion 390 according to the third embodiment, the circumferential position of the groove 727 of the outer cylindrical portion 72 constituting 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] In other words, the guide case 370 has a fitting recess 371 formed between the groove 727 and the outer peripheral 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 peripheral recess 723.

[0058] Furthermore, the elastic portion 390 is provided with protrusions 394 that project inward from the inner circumferential surface 935 at both circumferential ends of the notch 931 in the outer peripheral seal portion 393, which 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] Then, when positioning the sealing member 380 on the second side of the rod guide 360, the protrusions 394 provided at both circumferential ends of the notch 931 are fitted into the fitting recess 371 of the guide case 370. As a result, the circumferential position of the groove 727 of the outer cylindrical portion 72 constituting the first flow path 751 and the circumferential position of the notch 931 of the outer peripheral sealing portion 393 coincide with a high degree of accuracy. Consequently, the 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 moving circumferentially.

[0060] In the guide case 370 and elastic portion 390 according to the third embodiment, the circumferential position of the groove 727 and the circumferential position of the notch 931 coincide with a high degree of accuracy, so the number of notches 931 may be the same as the number of grooves 727. Also, the number of grooves 727 and notches 931 may be less than the number in the first embodiment. For example, the number of grooves 727 and notches 931 may each be two.

[0061] <Fourth Embodiment> Figure 8 shows an example of a schematic configuration of the sealing member 480 according to the fourth embodiment. The sealing member 480 according to the fourth embodiment differs from the sealing member 80 according to the first embodiment in that it has a ring 481 corresponding to the ring 81 and an elastic part 490 corresponding to the elastic part 90. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and fourth embodiments, and their detailed descriptions will be omitted.

[0062] Ring 481 differs from ring 81 according to the first embodiment in that its first end face 811 is configured to contact the second end face 720 of the guide case 70. In other words, ring 481 has multiple (for example, 8) recesses 482 formed at equal intervals in the circumferential direction, recessed from the first end face 811 toward the second side in the radial center.

[0063] The elastic portion 490 differs from the elastic portion 90 in the first embodiment in that it has a connecting portion 495 that connects the outer peripheral sealing portion 93 and the central sealing portion 94. The connecting portion 495 is provided only in the portion of the ring 481 where the recess 482 is formed, and connects the outer peripheral sealing portion 93 and the central sealing portion 94 only in the portion where the recess 482 is formed.

[0064] In other words, in the sealing member 480 according to the fourth embodiment, the first side end face 811, which does not have a recess 482 formed thereon, is exposed without being covered by the elastic portion 490. When the rod guide 60 and the sealing member 480 are assembled, the first side end face 811 contacts the second side end face 720 of the guide case 70. As a result, the reduction in axial holding force by the second side end of the inwardly bent outer cylinder 12 due to the interposition of an elastic body between the ring 481 of the sealing member 480 and the guide case 70 is suppressed.

[0065] <Fifth Embodiment> Figure 9 shows an example of a perspective view of the rod guide 560 according to the fifth embodiment as seen from the second side, and an example of a perspective view of the sealing member 580 according to the fifth embodiment as seen from the first side. Figure 10 shows an example of a cross-section of the rod guide 560 and sealing 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 different guide case 570, which corresponds to the guide case 70. Also, the sealing member 580 according to the fifth embodiment differs from the sealing member 80 according to the first embodiment in that it has an elastic part 590, which corresponds to the elastic part 90. The differences from the first embodiment will be described below. The same reference numerals are used for the same parts in the first and fifth embodiments, and their detailed descriptions 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 formed thereon. The elastic portion 590 differs from the elastic portion 90 in the first embodiment in that the connecting portion 595 corresponds to the connecting portion 95. In the connecting portion 595, a recess 596 is formed in the outer peripheral sealing portion 93 where a notch 931 is formed, extending from the first end face. The recess 596 is formed to be continuous with the notch 931.

[0067] In the guide case 570 and elastic part 590 according to the fifth embodiment, with the first end face of the connecting part 595 of the elastic part 590 in contact with the second end face 720 of the outer cylindrical part 72 of the guide case 70, oil that has passed through the gap between the rod 20 and the guide 61 to the second side of the inner cylindrical part 71 of the guide case 570 flows through the recess 596 of the connecting part 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 part 595.

[0068] According to the rod guide 560 and sealing member 580 of the fifth embodiment, there is no need to form a groove 727 in the guide case 570, so the mold used to form the guide case 570 can be made simpler. In addition, the oil that has passed through the recess 596 of the connecting portion 595 can be quickly returned to the reservoir chamber R via the notch 931 and the outer peripheral recess 723 without moving in the circumferential direction. [Explanation of symbols]

[0069] 1...Suspension device, 2...Buffing device, 3...Coil spring (example of a spring), 10...Cylinder section, 11...Inner cylinder, 12...Outer cylinder, 20...Rod, 30...Piston section, 60...Rod guide, 75...Flow path, 80...Seal member, 91...Seal lip section (example of the first seal section), 93...Outer circumference seal section (example of the second seal section), 94...Central seal section, 95...Connection section, 100...Contact section, 722...Outer recess, 723...Outer circumference recess, 724...Inclined surface (example of the pressed section), 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 section, 938...Protruding section, R...Reservoir chamber

Claims

1. An inner cylinder in which the working fluid is sealed, An outer cylinder provided on the outer circumference of the inner cylinder, forming a reservoir chamber between itself and the inner cylinder for storing the working fluid, A piston portion that partitions the space formed inside the inner cylinder, A rod having one end holding the piston portion and the other end protruding from the opening of the outer cylinder, A rod guide is provided to slidably support the rod, and whose outer circumference contacts the inner surface of the outer cylinder, A sealing member having a first sealing portion that seals the space between the rod and the rod, and a second sealing portion that seals the space between the rod and the inner surface of the outer cylinder, provided on the opening side of the rod guide in the axial direction of the rod, Equipped with, The rod guide has a pressing portion provided at the end of the outer circumference on the opening side, against which the inner portion of the portion of the second sealing portion that contacts the inner surface of the outer cylinder is pressed, and an outer recess recess recessed from the outer surface, forming an outer channel that returns the working fluid to the reservoir chamber between itself and the inner surface of the outer cylinder. The portion of the second seal portion that is pressed against the object to be pressed has a notch formed in it that creates a relay channel for the working fluid that has passed through the gap between the rod guide and the rod to the opening side to flow towards the outer peripheral channel. Buffer device.

2. The rod guide has a groove formed therein that connects the inner and outer sides of the contact portion. The shock absorber according to claim 1.

3. The rod guide has a plurality of grooves that connect the inner and outer sides of the contact portion. The number of notches is greater than the number of grooves. The shock absorber according to claim 1.

4. Either the number of grooves or the number of notches is even, and the other is odd. The buffer device according to claim 3.

5. Four or more of the notches communicate with each other in relation to the multiple grooves. The shock absorber according to claim 4.

6. The rod guide communicates with the groove and forms a circumferential flow path between itself and the sealing member through which the working fluid moves in the circumferential direction. The buffer device according to claim 2.

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

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

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

10. The aforementioned notch is provided with a projection that extends from the bottom surface toward the rod guide. The shock absorber according to claim 9.

11. A buffer device according to any one of claims 1 to 10, A spring arranged around the aforementioned shock absorber, A suspension system equipped with [a specific feature].

Images