Buffer device, suspension device

Abstract

A shock absorbing device 2 comprises: a cylinder 11; an outer cylinder 12 that is disposed on the outside of the cylinder 11 and that covers the cylinder 11; a piston part that partitions a hydraulic oil chamber formed inside the cylinder 11; a reservoir chamber that is formed between the cylinder 11 and the outer cylinder 12, a bottom side of the reservoir chamber being filled with hydraulic oil and an opening side of the cylinder 11 being filled with gas; a rod guide part 60 that is disposed at the opening, that slidably supports a rod holding the piston part at one end, and that has a flow path 75 for returning hydraulic oil, which has passed through a gap between the rod guide part and the rod and reached the opening side, to the reservoir chamber; and a guide member 100 that is disposed in the reservoir chamber, that is contacted multiple times by outflow oil, which is hydraulic oil flowing out from the flow path 75 rather than the hydraulic oil in the reservoir chamber, and that guides the outflow oil to the outer cylinder 12.

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 end of the cylinder and the open end of 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. The 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 the 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.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the temperature of the hydraulic oil rises, the life of the hydraulic oil may be shortened or the seal of the seal member may deteriorate. Therefore, it is desirable to prevent the temperature of the hydraulic oil from rising too high. An object of the present invention is to provide a shock absorber and the like that can prevent the temperature of the hydraulic oil from rising too high.

Means for Solving the Problems

[0005] The present invention, completed with this objective in mind, is a buffer device comprising: a cylinder; an outer cylinder body disposed outside the cylinder and covering the cylinder; a piston portion that partitions an oil chamber for hydraulic fluid formed inside the cylinder; a reservoir chamber formed between the cylinder and the outer cylinder body, with the hydraulic fluid filling the bottom side and gas filling the opening side of the cylinder; a support member disposed at the opening, slidably supporting a rod that holds the piston portion at one end, and having a passage formed therein that returns the hydraulic fluid that has reached the opening side through the gap with the rod back to the reservoir chamber; and a guide member disposed in the reservoir chamber, which comes into contact more with spilled hydraulic fluid that has flowed out from the passage than with the hydraulic fluid inside the reservoir chamber, and guides the spilled hydraulic fluid to the outer cylinder body. Here, the guide member may be positioned in a location that does not come into contact with the hydraulic fluid in the reservoir chamber. Furthermore, the guide member may have a protruding portion that extends from the outer circumference of the cylinder toward the outer cylinder. Furthermore, the guide member may be fitted into the cylinder. Furthermore, the guide member may be fitted into the support member. Furthermore, the guide member may be sandwiched between the support member and the cylinder. Furthermore, the guide member may be provided integrally with the cylinder. Furthermore, the guide member may be provided integrally with the support member. Furthermore, the guide member may have a cylindrical portion positioned between the cylinder and the outer cylinder, and a connecting portion connecting the cylindrical portion and the cylinder, and may be capable of storing the spilled oil in the space formed by the cylindrical portion, the connecting portion and the cylinder. 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 buffer device, etc., that can prevent the temperature of the hydraulic fluid from becoming too high. [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 figure shows an example of a partial cross-section of a shock absorber according to the first embodiment. [Figure 3] This figure shows an example of how a shock absorber works. [Figure 4] This figure shows an example of how a shock absorber works. [Figure 5] This figure shows an example of how a shock absorber works. [Figure 6] This figure shows an example of a cross-section of a guide member according to the second embodiment. [Figure 7] This figure shows an example of a cross-section of a guide member according to the third embodiment. [Figure 8] This figure shows an example of a cross-section of a guide member according to the fourth embodiment. [Figure 9] This figure shows an example of a cross-section of a guide member according to the fifth embodiment. [Figure 10] This figure shows an example of a cross-section of a guide member according to the sixth embodiment. [Figure 11] This figure shows an example of a cross-section of a guide member according to the seventh embodiment. [Figure 12] This figure shows an example of a view of the guide member according to the seventh embodiment from the outside. [Figure 13] This figure shows an example of a cross-section of a buffer device to which the modified outer cylinder is applied. [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. FIG. 2 is a diagram showing an example of a partial cross-section of the shock absorber 2 according to the first embodiment. FIG. 2 is an enlarged view of the II-II section in FIG. 1. The suspension device 1 is a strut-type suspension used for a four-wheeled vehicle such as a passenger car. As shown in FIG. 1, it includes a hydraulic shock absorber 2 and a coil spring 3 disposed outside the shock absorber 2. The suspension device 1 also includes a lower spring seat 4 that supports the end of the coil spring 3 on the first side (the lower side in FIG. 1) in the axial direction of a rod 20 described later, and an upper spring seat 5 that supports the end of the coil spring 3 on the second side (the upper side in FIG. 1) in the axial direction of the rod 20.

[0009] The suspension device 1 further includes a vehicle body side bracket 6 attached to the end of the rod 20 on the second side in the axial direction for attaching the suspension device 1 to the vehicle, and a wheel side bracket 7 fixed to the end of the rod 20 on the first side in the axial direction in a cylinder portion 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 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 center line direction of a cylindrical cylinder 11 described later. Also, the first side (the lower side in FIG. 1) and the second side (the upper side in FIG. 1) in the axial direction may be simply 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 cylinder 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] Hereinafter, the shock absorber 2 will be described in detail. The buffer device 2 includes a cylinder part 10 that houses hydraulic 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. Further, the buffer device 2 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. Also, the buffer device 2 includes a rebound seat 50 fixed to the rod 20 and a rebound rubber 51, which is an annular elastic member disposed on the second side of the rebound seat 50, in order to mitigate the impact when the rod 20 extends.

[0012] The cylinder part 10 includes a thin-walled cylindrical cylinder 11, a thin-walled cylindrical outer cylinder body 12 provided outside the cylinder 11, and a bottom cover 13 that closes the first-side end of the outer cylinder body 12. The cylinder 11 and the outer cylinder body 12 are arranged such that the central axis 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 cylinder 11 and the inner peripheral surface of the outer cylinder body 12. The reservoir chamber R is filled with hydraulic oil on the first side and gas on the second side.

[0013] Also, the cylinder part 10 includes a rod guide part 60 that supports the rod 20 movably, a bump stopper cap 15 attached to the second-side end of the outer cylinder body 12, and a seal member 80 that prevents leakage of the hydraulic oil in the cylinder part 10 and entry of foreign matter into the cylinder part 10.

[0014] Also, the cylinder part 10 includes a guide member 100 that is disposed in the reservoir chamber R and guides the hydraulic oil flowing out from a flow path 75, which will be described later, formed in the rod guide part 60, to the outer cylinder body 12. The rod guide part 60, the seal member 80, and the guide member 100 will be described in detail later.

[0015] The rod 20 is a rod-shaped member that extends 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.

[0016] The piston section 30 includes a piston 31, a valve group 32 that closes the first end of some of the oil passages among the plurality of oil passages formed in the piston 31, and a valve group 33 that closes the second end of some of the oil passages formed in the piston 31. The piston 31 contacts the inner surface of the cylinder 11 via a sealing member provided on its outer surface, dividing the space inside the cylinder 11, which is filled with hydraulic fluid, into a first oil chamber Y1 located first to the piston 31 and a second oil chamber Y2 located second to the piston 31.

[0017] As shown in Figure 1, the bottom portion 40 includes a valve body 41 having a plurality of oil passages that penetrate 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 section 40 separates the first oil chamber Y1 and the reservoir chamber R.

[0018] [Rod guide section 60] The rod guide section 60 comprises a thin-walled cylindrical guide 61 positioned on the inside and a guide case 70 that holds the guide 61 on the inside.

[0019] 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.

[0020] 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.

[0021] A guide 61 is fitted inside the inner cylindrical portion 71. The outer diameter of the inner cylindrical portion 71 is molded to be smaller than the inner diameter of the cylinder 11, and it is positioned inside the cylinder 11. The outer cylindrical portion 72 is positioned between the rod 20 and the outer cylinder 12 on the second side of the cylinder 11. The outer diameter of the outer cylindrical portion 72 is smaller than the inner diameter of the second end of the outer cylinder 12.

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

[0023] The second opening in the inner recess 721 is chamfered. The outer recess 722 is cylindrical, and the outer diameter of the second end of the outer cylindrical portion 72 gradually decreases as it moves towards the second side. The outer peripheral recess 723 is cylindrical. However, the outer peripheral recess 723 is formed such that the outer diameter of the first end of the outer cylindrical portion 72 is larger than the outer diameter of the cylinder 11. In addition, a sloping surface 724 is formed on the second side of the outer peripheral recess 723, where the outer diameter of the outer cylindrical portion 72 gradually decreases towards the first side.

[0024] Furthermore, a flow path 75 is formed in the outer cylindrical portion 72 that returns the hydraulic fluid, which has passed through the gap between the rod 20 and the guide 61 to the second side of the guide case 70, back to the reservoir chamber R. For example, the opening on the second side of the flow path 75 is located outside the central seal portion 824 of the seal member 80, which will be described later, in the inner recess 721, but inside the outer recess 722. For example, the opening on the first side of the flow path 75 is formed on the inclined surface 724.

[0025] Furthermore, at least one channel 75 is formed in the circumferential direction of the guide case 70. If multiple channels 75 are formed in the circumferential direction, they may be formed, for example, every 90 degrees or every 180 degrees. 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.

[0026] [Sealing component 80] The sealing member 80 has an annular ring 81 formed from a metal such as steel, and an elastic portion 82 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 82 to the ring 81 by heat, and the ring 81 holds the elastic portion 82.

[0027] The ring 81 is annular in shape, and its inner diameter is larger than the outer diameter of the rod 20, its outer diameter is smaller than the inner diameter of the second end of the outer cylinder 12, and is greater than or equal to the outer diameter of the outer cylindrical portion 72 of the guide case 70.

[0028] The elastic portion 82 is provided on the first side of the ring 81, has a wedge-shaped cross-section, and includes a seal lip portion 821 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 82 is also provided on the second side of the ring 81 and includes a dust lip portion 822 that adheres tightly to the entire circumference of the outer surface of the rod 20 to suppress the intrusion of dust from the outside.

[0029] Furthermore, the elastic portion 82 has an outer peripheral sealing portion 823 that protrudes over its entire circumference from the outer circumference of the ring 81 in a direction that is axially inclined toward the first side and outward. The outer peripheral sealing portion 823 is located in the outer recess 722 of the guide case 70 of the rod guide portion 60 and contacts the inner circumferential surface of the outer cylinder 12, thereby suppressing leakage of hydraulic fluid from the gap between the outer circumferential surface of the guide case 70 and the inner circumferential surface of the outer cylinder 12.

[0030] Furthermore, the elastic portion 82 has a central seal portion 824 that protrudes from the inner circumference of the ring 81 in a direction that is axially inclined toward the first side and outward over its entire circumference. The central seal portion 824 contacts the inner recess 721 of the outer cylindrical portion 72 of the guide case 70, thereby suppressing the flow of hydraulic fluid or gas filled in the reservoir chamber R through the flow path 75 inward.

[0031] When assembling the shock absorber 2, the sealing member 80 is inserted into the outer cylinder 12 after the rod guide portion 60 has been inserted into the outer cylinder 12, until the first end face 810 of the ring 81 contacts the second end face of the outer cylindrical portion 72 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.

[0032] [Guidance member 100] The guide member 100 has a cylindrical portion 110 positioned between the cylinder 11 and the outer cylinder 12, and a connecting portion 120 that connects the cylindrical portion 110 and the cylinder 11. An example of the guide member 100 being formed is that it is made by drawing a thin metal sheet.

[0033] The cylindrical portion 110 is positioned closer to the outer cylinder 12 than to the cylinder 11. For example, the gap G1 between the cylindrical portion 110 and the outer cylinder 12 may be 0.5 mm to 1 mm, and the gap G2 between the cylindrical portion 110 and the cylinder 11 may be 2 mm or more. The connecting portion 120 has a cylindrical fitting portion 121 that fits onto the outer circumferential surface of the cylinder 11, and an inclined portion 122 that is inclined axially to the second side and outward from the second end of the fitting portion 121. The second end of the inclined portion 122 connects to the first end of the cylindrical portion 110.

[0034] The guide member 100 is held in place by the cylinder 11, with the fitting portion 121 being fitted onto the outer circumferential surface of the cylinder 11. For example, the fitting portion 121 may be press-fitted onto the outer circumferential surface of the cylinder 11. Alternatively, the fitting portion 121 may be joined to the outer circumferential surface of the cylinder 11, for example, by welding or adhesive.

[0035] The guide member 100, configured as described above, is positioned at the second end of the cylinder 11 so as not to come into contact with the hydraulic fluid (hereinafter sometimes referred to as "retained oil Os") located on the first side of the reservoir chamber R. In other words, even if the surface of the hydraulic fluid (retained oil Os) in the reservoir chamber R becomes turbulent due to the high-speed movement of the piston portion 30, the guide member 100 is positioned so that the hydraulic fluid in the reservoir chamber R does not come into contact with the guide member 100.

[0036] As described above, the shock absorber 2 comprises a cylinder 11, an outer cylinder 12 positioned outside the cylinder 11 and covering the cylinder 11, and a piston portion 30 that partitions the hydraulic fluid chambers (e.g., first oil chamber Y1, second oil chamber Y2) formed inside the cylinder 11. The shock absorber 2 also includes a reservoir chamber R formed between the cylinder 11 and the outer cylinder 12, with hydraulic fluid filled on the bottom side (e.g., first side, bottom cover 13 side) and gas filled on the opening side of the cylinder 11 (e.g., second side). The shock absorber 2 also includes a rod guide portion 60, which is positioned at the opening of the cylinder 11 and slidably supports a rod 20 that holds the piston portion 30 at one end (e.g., first side), and has a passage 75 formed therein that returns the hydraulic fluid that has passed through the gap with the rod 20 to the opening side (e.g., second side) back to the reservoir chamber R. Furthermore, the buffer device 2 is positioned in the reservoir chamber R and includes a guide member 100 that contacts the spilled oil Of (see Figure 3), which is the hydraulic fluid that has leaked out from the flow path 75, more often than the stored oil Os, which is an example of the hydraulic fluid in the reservoir chamber R, and guides the spilled oil Of to the outer cylinder 12.

[0037] Figure 3 shows an example of the operation of the buffer device 2. Figure 4 shows an example of the operation of the buffer device 2. In the buffer device 2 configured as described above, the leaked oil Of, which is the hydraulic fluid that flows out from the flow path 75, accumulates in the space S1 formed between the inside of the cylindrical portion 110 and the connecting portion 120 of the guide member 100 and the outer circumferential surface of the cylinder 11. Then, as shown in Figure 4, the leaked oil Of that overflows from the space S1 falls to the first side through the gap between the cylindrical portion 110 of the guide member 100 and the outer cylinder 12. Since the gap G1 between the cylindrical portion 110 and the outer cylinder 12 is narrow, the leaked oil Of that overflows from the space S1 falls while contacting the inner circumferential surface of the outer cylinder 12. Since the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the leaked oil Of is cooled by contacting the outer cylinder 12. Then, the cooled leaked oil Of mixes with the hydraulic fluid in the reservoir chamber R, lowering the temperature of the hydraulic fluid in the cylinder portion 10. As a result, the temperature of the hydraulic fluid in the cylinder portion 10 can be prevented from becoming too high and can not exceed a predetermined temperature. The predetermined temperature is determined considering the lifespan of the hydraulic fluid and the temperature at which the elastic portion 82 of the seal member 80 deteriorates.

[0038] Figure 5 shows an example of the operation of the buffer device 2. As shown in Figure 5, depending on the type of four-wheeled vehicle, when the four-wheeled vehicle is placed on a horizontal plane, the suspension system 1 may be mounted on the four-wheeled vehicle at an inclination with respect to the direction perpendicular to the horizontal plane (inclination at an angle θ (e.g., 30 degrees)).

[0039] Thus, even when the suspension device 1 is mounted on a four-wheeled vehicle in an inclined state, the shock absorber 2 can reliably store the hydraulic fluid that flows out from the flow path 75 in the space S1, and reliably bring the hydraulic fluid that overflows from the space S1 into contact with the outer cylinder 12.

[0040] <Second Embodiment> Figure 6 shows an example of a cross-section of the guide member 200 according to the second embodiment. The guide member 200 according to the second embodiment differs from the guide member 100 according to the first embodiment in that the cylindrical portion 210 corresponds to the cylindrical portion 110. 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.

[0041] The cylindrical portion 210 has a cylindrical body 211 and a projection 212 provided at the second end of the body 211 that protrudes from the inside to the outside along its entire circumference. For example, the gap G3 between the outer end of the projection 212 and the outer cylinder 12 is 0.5 mm to 1 mm, and the gap G4 between the body 211 and the cylinder 11 is 1 mm or more. The protruding portion 212 may be formed perpendicular to the axial direction, or it may be formed in an arc shape with the second side being convex.

[0042] In the guide member 200 configured as described above, the hydraulic fluid that flows out from the flow path 75 (in other words, the flowing fluid Of (see, for example, Figure 3)) falls onto the protruding portion 212 of the guide member 200, and some of it moves outward along the protruding portion 212 and falls through the space between the protruding portion 212 and the outer cylinder 12. Also, some of the hydraulic fluid that flows out from the flow path 75 and falls onto the protruding portion 212 of the guide member 200 moves inward along the protruding portion 212 and accumulates in the space S2 formed between the inside of the cylindrical portion 210 and the connecting portion 120 of the guide member 200 and the outer circumferential surface of the cylinder 11. Then, the hydraulic fluid that overflows from space S2 falls through the space between the protruding portion 212 of the guide member 200 and the outer cylinder 12. Since the gap G3 between the protruding portion 212 and the outer cylinder 12 is narrow, the hydraulic fluid that overflows from space S2 easily falls while in contact with the inner circumferential surface of the outer cylinder 12. Furthermore, since the outer surface of the outer cylinder 12 is exposed to the outside air, the hydraulic fluid is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 200, it is possible to prevent the temperature of the hydraulic fluid inside the cylinder section 10 from becoming too high.

[0043] <Third Embodiment> Figure 7 shows an example of a cross-section of the guide member 300 according to the third embodiment. The guide member 300 according to the third embodiment differs from the guide member 100 according to the first embodiment in that it does not have a space S1 for storing the hydraulic fluid that has flowed out from the flow path 75. 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.

[0044] The guide member 300 has a cylindrical fitting portion 310 that is fitted onto the outer circumferential surface of the cylinder 11, and a protruding portion 320 that protrudes from the first end of the fitting portion 310 along its entire circumference in a direction inclined axially toward the first side and outward. Furthermore, the gap G5 between the outer end of the protrusion 320 and the outer cylinder 12 can be exemplified as being, for example, 0.5 mm to 1 mm.

[0045] In the guide member 300 configured as described above, the hydraulic fluid that flows out from the flow path 75 (in other words, the flowing fluid Of (see, for example, Figure 3)) falls onto the protrusion 320 of the guide member 300, then moves along the protrusion 320 to the first side and outward, and falls through the gap between the protrusion 320 and the outer cylinder 12. In this way, the guide member 300 guides more of the hydraulic fluid that flows out from the flow path 75 to the outer cylinder 12 than to the cylinder 11. Furthermore, since the gap G5 between the protrusion 320 and the outer cylinder 12 is narrow, the hydraulic fluid that falls through the gap between the protrusion 320 and the outer cylinder 12 tends to fall while in contact with the inner circumferential surface of the outer cylinder 12. Furthermore, since the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic fluid is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 300, it is possible to prevent the temperature of the hydraulic fluid inside the cylinder 10 from becoming too high.

[0046] Furthermore, multiple notches recessed inward from the outer circumference may be formed in the circumferential direction at the outer end of the protruding portion 320 of the guide member 300. This helps to prevent the temperature of the hydraulic fluid inside the cylinder portion 10 from becoming too low due to an increase in the amount of spilled oil Of that comes into contact with the inner circumferential surface of the outer cylinder 12.

[0047] <Fourth Embodiment> Figure 8 shows an example of a cross-section of the guide member 400 according to the fourth embodiment. The guide member 400 according to the fourth embodiment differs from the guide member 100 according to the first embodiment in that it does not have a space S1 for storing the hydraulic fluid that has flowed out from the flow path 75. 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.

[0048] The guide member 400 has a cylindrical fitting portion 410 that fits onto the outer circumferential surface of the cylinder 11, and a projection portion 420 that protrudes outward from the second end of the fitting portion 410 along its entire circumference. The projection portion 420 may be formed to be perpendicular to the axial direction, or it may be formed to be inclined axially toward the first side and outward. Furthermore, the gap G6 between the outer end of the protrusion 420 and the outer cylinder 12 can be exemplified as, for example, 0.5 mm to 1 mm.

[0049] In the guide member 400 configured as described above, the hydraulic fluid that flows out from the flow path 75 falls onto the protrusion 420 of the guide member 400, then moves outward along the protrusion 420, and falls through the gap between the protrusion 420 and the outer cylinder 12. Since the gap G6 between the protrusion 420 and the outer cylinder 12 is narrow, the hydraulic fluid falling through the gap between the protrusion 420 and the outer cylinder 12 tends to fall while in contact with the inner circumferential surface of the outer cylinder 12. Furthermore, since the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic fluid is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 400, it is possible to prevent the temperature of the hydraulic fluid from becoming too high.

[0050] The guide member 400 is molded separately from the cylinder 11 and then integrated with the cylinder 11 by being fitted into or joined to the cylinder 11. However, the invention is not limited to this configuration. For example, the guide member 400 and the cylinder 11 may be molded integrally. When the guide member 400 and the cylinder 11 are molded integrally, the fitting portion 410 is not necessarily required, and only the protruding portion 420 may be provided. In other words, the protruding portion 420 may protrude outward from the second end of the cylinder 11.

[0051] <Fifth Embodiment> Figure 9 shows an example of a cross-section of the guide member 500 according to the fifth embodiment. The guide member 500 according to the fifth embodiment differs from the guide member 400 according to the fourth embodiment in that it is integrated with the guide case 70 of the rod guide portion 60. The differences from the fourth embodiment will be described below. The same reference numerals are used for the same parts in the fourth and fifth embodiments, and their detailed descriptions will be omitted.

[0052] The guide member 500 has a cylindrical fitting portion 510 that fits onto the first end of the outer cylindrical portion 72 of the guide case 70, and a projection portion 520 that protrudes outward around the entire circumference from the second end of the fitting portion 510. The projection portion 520 may be formed to be perpendicular to the axial direction, or it may be formed to be inclined with respect to the axial direction on the first side and outward. Furthermore, the gap G7 between the outer end of the protrusion 520 and the outer cylinder 12 can be exemplified as being, for example, 0.5 mm to 1 mm.

[0053] The guide member 500 is held in the guide case 70 by the fitting portion 510 being fitted onto the outer circumferential surface of the outer cylindrical portion 72 of the guide case 70. For example, the fitting portion 510 may be press-fitted onto the outer circumferential surface of the guide case 70. Alternatively, the fitting portion 510 may be joined to the outer circumferential surface of the guide case 70, for example, by welding or adhesive.

[0054] In the guide member 500 configured as described above, the hydraulic fluid that flows out from the flow path 75 falls onto the protrusion 520 of the guide member 500, then moves outward along the protrusion 520, and falls through the gap between the protrusion 520 and the outer cylinder 12. Since the gap G7 between the protrusion 520 and the outer cylinder 12 is narrow, the hydraulic fluid that falls through the gap between the protrusion 520 and the outer cylinder 12 tends to fall while in contact with the inner circumferential surface of the outer cylinder 12. Furthermore, since the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic fluid is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 500, it is possible to prevent the temperature of the hydraulic fluid from becoming too high.

[0055] The guide member 500 is molded separately from the guide case 70, and then integrated with the guide case 70 by being fitted into or joined to the guide case 70. However, the invention is not limited to this configuration. For example, the guide member 500 and the guide case 70 may be molded integrally. If the guide member 500 and the guide case 70 are molded integrally, the fitting portion 510 is not necessarily required, and only the protruding portion 520 may be provided.

[0056] Furthermore, the guide member 500 according to the fifth embodiment may be provided together with the guide member 400 according to the fourth embodiment.

[0057] <Sixth Embodiment> Figure 10 shows an example of a cross-section of the guide member 600 according to the sixth embodiment. The guide member 600 according to the sixth embodiment differs from the guide member 400 according to the fourth embodiment in that it is not integrated with the cylinder 11, but is sandwiched between the cylinder 11 and the guide case 70 of the rod guide portion 60. The differences from the fourth embodiment will be described below. The same reference numerals are used for the same parts in the fourth and sixth embodiments, and their detailed descriptions will be omitted.

[0058] The guide member 600 is an annular member formed from a thin plate. The guide member 600 may be formed to be perpendicular to the axial direction, or the outer portion may be formed to be inclined with respect to the axial direction toward the first side and outward.

[0059] As shown in Figure 10, the guide member 600 is held in place by being sandwiched between the second end of the cylinder 11 and the first end of the guide case 70. Furthermore, the gap G8 between the outer end of the guide member 600 and the outer cylinder 12 can be exemplified as, for example, 0.5 mm to 1 mm.

[0060] In the guide member 600 configured as described above, the hydraulic fluid that flows out from the flow path 75 falls onto the guide member 600, then moves outward along the guide member 600, and falls through the gap between the guide member 600 and the outer cylinder 12. Since the gap G8 between the guide member 600 and the outer cylinder 12 is narrow, the hydraulic fluid falling through the gap between the guide member 600 and the outer cylinder 12 tends to fall while in contact with the inner circumferential surface of the outer cylinder 12. Furthermore, since the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic fluid is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 600, it is possible to prevent the temperature of the hydraulic fluid from becoming too high.

[0061] <Seventh Embodiment> Figure 11 shows an example of a cross-section of the guide member 700 according to the seventh embodiment. Figure 12 shows an example of a perspective view of the guide member 700 according to the seventh embodiment, as seen from the second side. The guide member 700 according to the seventh embodiment differs from the guide member 400 according to the fourth embodiment in that the protrusion 720 corresponding to the protrusion 420 is not formed around the entire circumference, but rather multiple protrusions are formed in the circumferential and axial directions. The differences from the fourth embodiment will be described below. The same reference numerals are used for the same parts in the fourth and seventh embodiments, and their detailed descriptions will be omitted.

[0062] The guide member 700 has a fitting portion 710 that fits onto the outer circumferential surface of the cylinder 11, and a projection portion 720 that protrudes outward from the outer circumferential surface of the fitting portion 710. The projection portion 720 can be exemplified as being rectangular in shape and formed perpendicular to the axial direction. Multiple projection portions 720 are provided in the circumferential and axial directions. In the example shown in Figure 12, eight projection portions 720 are formed in the circumferential direction (at 45-degree intervals) and four stages in the axial direction, and the circumferential phase of the eight projection portions 720 provided in adjacent stages is shifted by 22.5 degrees. When viewed in the axial direction, at the first side of both ends in the circumferential direction of a single projection portion 720, projection portions 720 of stages located first to the stage on which the single projection portion 720 is provided are arranged. For example, the projection portion 720 can be exemplified as being formed over approximately 30 degrees in the circumferential direction.

[0063] In the guide member 700 configured as described above, after the hydraulic fluid (in other words, the leaked oil Of (see, for example, Figure 3)) that flows out from the flow path 75 falls onto the protrusion 720, a portion of the hydraulic fluid moves circumferentially on the protrusion 720 and falls onto the protrusion 720 of a step located first to the step on which the hydraulic fluid that flowed out from the flow path 75 fell. Subsequently, a portion of the hydraulic fluid that fell onto the protrusion 720 falls onto the protrusion 720 of a step located first to the step on which the protrusion 720 is located. In this way, the hydraulic fluid that flows out from the flow path 75 falls while moving circumferentially from the protrusion 720 of the step located second to the protrusion 720 of the step located first. Furthermore, the speed at which the hydraulic fluid flowing out of the flow path 75 reaches the hydraulic fluid stored on the first side of the reservoir chamber R is smaller when it falls while moving over the multiple protrusions 720 than when it falls through the space between the protrusions 720 and the outer cylinder 12. In other words, the hydraulic fluid flowing out of the flow path 75 falls slowly while moving over the multiple protrusions 720. As a result, the hydraulic fluid falling while moving over the multiple protrusions 720 is cooled more than the hydraulic fluid falling through the space between the protrusions 720 and the outer cylinder 12. Therefore, the guide member 700 can reliably prevent the temperature of the hydraulic fluid from becoming too high.

[0064] <Modified form of the outer cylinder 12> Figure 13 shows an example of a cross-section of the buffer device 2 to which the modified outer cylinder 912 is applied. As shown in Figure 13, the modified outer cylinder 912 has an inner projection 913 at the second end that protrudes inward from the inner circumferential surface over its entire circumference. The inner projection 913 is provided at a location where the hydraulic fluid flowing out from the flow path 75 (in other words, the flowing fluid Of (see, for example, Figure 3)) comes into contact with the hydraulic fluid stored in the reservoir chamber R before mixing with it. As a result, the hydraulic fluid flowing out from the flow path 75 comes into contact with the outer cylinder 912 in greater quantity and for a longer period, making it possible to further lower the temperature of the hydraulic fluid in the cylinder section 10. Consequently, the temperature of the hydraulic fluid in the cylinder section 10 can be prevented from exceeding a predetermined temperature.

[0065] The inner protrusion 913 can be exemplified by forming it by bulging the cylindrical member, but it may also be formed by other methods. Furthermore, the modified outer cylinder 912 can be applied regardless of which guide member is used, from the guide member 100 according to the first embodiment to the guide member 700 according to the seventh embodiment. [Explanation of Symbols]

[0066] 1...Suspension device, 2...Buffing device, 3...Coil spring (example of a spring), 10...Cylinder section, 11...Cylinder, 12...Outer cylinder, 20...Rod, 30...Piston section, 100, 200, 300, 400, 500, 600, 700...Guide member, 60...Rod guide section (example of a support member), 75...Flow path, 80...Seal member, 110...Cylindrical section, 120...Connection section, 212, 320, 420, 520, 720...Protruding section, Of...Outflow oil, Os...Reservoir oil, R...Reservoir chamber, S1...Space

Claims

1. Cylinder and An outer cylinder body positioned outside the cylinder and covering the cylinder, A piston portion that partitions the oil chamber for the hydraulic fluid formed in the cylinder, A reservoir chamber is formed between the cylinder and the outer cylinder, with the hydraulic fluid filling the bottom side and the gas filling the opening side of the cylinder. A support member is positioned in the opening and slidably supports a rod that holds the piston portion at one end, and has a passage formed therein that returns the hydraulic fluid that has reached the opening side through the gap with the rod back to the reservoir chamber. A guide member is provided which is arranged in the reservoir chamber and positioned between the cylinder and the outer cylinder, has a cylindrical portion connecting the cylindrical portion and the cylinder, a space formed by the cylindrical portion, the connection portion and the cylinder, capable of storing the spilled oil which is the hydraulic fluid that has flowed out from the flow path, and guides the spilled oil that overflows from the space to fall while contacting the inner circumferential surface of the outer cylinder, A shock absorber equipped with a shock absorber.

2. A cylinder and An outer cylinder body positioned outside the cylinder and covering the cylinder, A piston portion that partitions the oil chamber for the hydraulic fluid formed in the cylinder, A reservoir chamber formed between the cylinder and the outer cylinder, with the hydraulic fluid filling the bottom side and the gas filling the opening side of the cylinder; a support member positioned at the opening, slidably supporting a rod that holds the piston at one end, and having a passage formed therein that returns the hydraulic fluid that has reached the opening side through the gap with the rod to the reservoir chamber; A guide member is provided, which is arranged in the reservoir chamber and has a cylindrical fitting portion that fits onto the outer circumferential surface of the cylinder, and a protruding portion that extends from the piston-side end of the fitting portion in a direction inclined axially toward the piston and outward, and which guides the spilled oil, which is the hydraulic fluid that has flowed out from the passage, to fall while contacting the inner circumferential surface of the outer cylinder, A shock absorber equipped with a shock absorber.

3. The guide member is positioned in a location within the reservoir chamber that does not come into contact with the hydraulic fluid. The shock absorber according to claim 1.

4. The cylindrical portion of the guide member has a projection that extends from the outer circumference of the cylinder toward the outer cylinder. The shock absorber according to claim 1.

5. The guide member is fitted into the cylinder. The shock absorber according to claim 1.

6. The guide member is positioned in a location in the reservoir chamber that does not come into contact with the hydraulic fluid. The shock absorber according to claim 2.

7. The guide member is fitted into the cylinder, The shock absorber according to claim 2.

8. A buffer device according to any one of claims 1 to 7, A spring arranged around the aforementioned shock absorber, A suspension system equipped with [a specific feature].

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