Shock absorbing device, and 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

shock absorbers, suspension devices

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

[0002] For example, the shock absorber disclosed in Patent Document 1 includes a cylinder, an outer cylinder disposed outside the cylinder and covering the cylinder, and a rod guide that closes the open ends of the cylinder and the outer cylinder and supports a rod that is movably inserted into the cylinder. A piston connected to the lower end of the rod is slidably inserted below the cylinder, and the piston defines a rod-side chamber and a piston-side chamber that are filled with hydraulic oil within the cylinder. Furthermore, a reservoir filled with gas and hydraulic oil is formed between the cylinder and the outer cylinder. A seal member is stacked above the rod guide, and includes an annular insert metal, an inner seal that is held on the inner periphery of the insert metal and in sliding contact with the outer periphery of the rod, and an outer seal that is held on the outer periphery of the insert metal and in close contact with the outer periphery of the rod guide and the outer cylinder.

[0003] Patent No. 6080257

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

[0005] The present invention, which was completed with this object in mind, provides a shock absorber comprising: a cylinder; an outer cylindrical body disposed outside the cylinder and covering the cylinder; a piston portion defining an oil chamber for hydraulic oil formed within the cylinder; a reservoir chamber formed between the cylinder and the outer cylindrical body, the reservoir chamber being filled with hydraulic oil at its bottom side and gas at its opening side; a support member disposed at the opening, slidably supporting a rod holding the piston portion at one end thereof and having a flow path formed therein for returning the hydraulic oil that has passed through a gap between the rod and the support member and reaching the opening side to the reservoir chamber; and a guide member disposed in the reservoir chamber, the guide member being in contact with outflow oil (i.e., hydraulic oil flowing out of the flow path) more than the hydraulic oil in the reservoir chamber, and guiding the outflow oil to the outer cylindrical body. The guide member may be positioned so as not to come into contact with the hydraulic oil in the reservoir chamber. The guide member may also have a protrusion protruding from the outer periphery of the cylinder toward the outer cylindrical body. The guide member may also be fitted into the cylinder. The guide member may be fitted into the support member. The guide member may be sandwiched between the support member and the cylinder. The guide member may be provided integrally with the cylinder. The guide member may be provided integrally with the support member. The guide member may have a cylindrical portion disposed between the cylinder and the outer tubular body, and a connecting portion connecting the cylindrical portion to the cylinder, and may be capable of storing the spilled oil in a space formed by the cylindrical portion, the connecting portion, and the cylinder. From another perspective, the present invention is a suspension device including the above-described shock absorber and a spring disposed around the shock absorber.

[0006] According to the present invention, it is possible to provide a shock absorber or the like that can prevent the temperature of the hydraulic oil from becoming too high.

[0007] FIG. 1 is a diagram showing an example of a schematic configuration of a suspension device according to the first embodiment; FIG. 2 is a diagram showing an example of a partial cross section of a shock absorber according to the first embodiment; FIG. 3 is a diagram showing an example of the operation of a shock absorber; FIG. 4 is a diagram showing an example of the operation of a shock absorber; FIG. 5 is a diagram showing an example of a cross section of a guide member according to the second embodiment; FIG. 6 is a diagram showing an example of a cross section of a guide member according to the third embodiment; FIG. 7 is a diagram showing an example of a cross section of a guide member according to the fourth embodiment; FIG. 8 is a diagram showing an example of a cross section of a guide member according to the fifth embodiment; FIG. 9 is a diagram showing an example of a cross section of a guide member according to the sixth embodiment; FIG. 10 is a diagram showing an example of a cross section of a guide member according to the seventh embodiment; FIG. 11 is a diagram showing an example of a view of a guide member according to the seventh embodiment as seen from the outside; FIG. 12 is a diagram showing an example of a cross section of a shock absorber to which an outer cylinder according to a modified example is applied.

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

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

[0010] Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." The axial direction is also the direction of the center line of a cylindrical cylinder 11, which will be described later. Furthermore, the first axial side (the lower side in FIG. 1 ) and the second axial side (the upper side in FIG. 1 ) may be simply referred to as the "first side" and the "second side," respectively. Furthermore, a direction intersecting the axial direction (for example, a perpendicular direction) may be referred to as the "radial direction." In the radial direction, the side of 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] The shock absorber 2 will be described in detail below. The shock absorber 2 includes a cylinder portion 10 that contains hydraulic oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at the first end of the rod 20, and a bottom portion 40 that is provided at the first end of the cylinder portion 10. The shock absorber 2 also includes a rebound seat 50 that is fixed to the rod 20, and a rebound rubber 51 that is an annular elastic member that is arranged on the second side of the rebound seat 50, in order to absorb the impact when the rod 20 extends.

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

[0013] The cylinder portion 10 also includes a rod guide portion 60 that movably supports the rod 20, a bump stopper cap 15 attached to the second end of the outer cylinder body 12, and a sealing member 80 that prevents leakage of hydraulic oil within the cylinder portion 10 and the intrusion of foreign matter into the cylinder portion 10.

[0014] The cylinder portion 10 is also provided with a guide member 100 that is disposed in the reservoir chamber R and that guides the hydraulic oil that flows out from a flow path 75 (described later) formed in the rod guide portion 60 to the outer cylinder body 12. The rod guide portion 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 extending in the axial direction. The rod 20 holds the piston portion 30 on a first side. The rod 20 is connected to, for example, the vehicle body via the vehicle-side bracket 6 on a second side.

[0016] The piston section 30 includes a piston 31, a valve group 32 that closes first ends of some of the oil passages formed in the piston 31, and a valve group 33 that closes second ends of some of the oil passages formed in the piston 31. The piston 31 contacts the inner peripheral surface of the cylinder 11 via a seal member provided on its outer peripheral surface, and divides the space in the cylinder 11 in which the hydraulic oil is sealed 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.

[0017] 1, the bottom portion 40 includes a valve body 41 having a plurality of oil passages passing through in the axial direction, a valve 42 provided on a first side of the valve body 41, and a valve 43 provided on a second side of the valve body 41. The valve body 41 of the bottom portion 40 separates a first oil chamber Y1 from a reservoir chamber R.

[0018] [Rod Guide Section 60] The rod guide section 60 includes a thin-walled cylindrical guide 61 disposed inside, and a guide case 70 that holds the guide 61 inside.

[0019] The inner diameter of the guide 61 is set slightly larger than the outer diameter of the rod 20 inserted inside. For example, the inner diameter of the guide 61 is 0.1 mm to 1 mm larger than the outer diameter of the rod 20. Because the inner peripheral surface of the guide 61 comes into contact with the outer peripheral surface of the rod 20, the guide 61 is formed from a material that is more wear-resistant than the guide case 70.

[0020] The guide case 70 has a cylindrical inner cylindrical portion 71 provided on the inside, and a cylindrical outer cylindrical portion 72 provided on the outside of the inner cylindrical portion 71. The inner cylindrical portion 71 and the outer cylindrical portion 72 are integrally molded such that the outer peripheral surface of the second side portion of the inner cylindrical portion 71 and the inner peripheral surface of the first side portion of the outer cylindrical portion 72 are joined together.

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

[0022] The outer cylindrical portion 72 has an inner recess 721 formed at the inner end of the second side and recessed from the end face of the second side, an outer recess 722 formed at the outer end of the second side and recessed from the end face of the second side, and an outer peripheral recess 723 formed from the end of the first side to the center and recessed from the outer peripheral surface.

[0023] The opening on the second side of the inner recess 721 is chamfered. The outer recess 722 is cylindrically recessed, and is formed so that the outer diameter of the second-side end of the outer cylindrical portion 72 gradually decreases toward the second side. The outer peripheral recess 723 is cylindrically recessed. However, the outer peripheral recess 723 is formed so that the outer diameter of the first-side end of the outer cylindrical portion 72 is larger than the outer diameter of the cylinder 11. Furthermore, the second-side portion of the outer peripheral recess 723 is formed with an inclined surface 724, so that the outer diameter of the outer cylindrical portion 72 gradually decreases toward the first side.

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

[0025] The flow path 75 is formed in at least one location in the circumferential direction of the guide case 70. When a plurality of flow paths 75 are formed in the circumferential direction, they may be formed, for example, every 90 degrees or every 180 degrees. The guide case 70 configured as described above may be formed, for example, from a metal such as steel or a non-metallic material such as polytetrafluoroethylene.

[0026] [Sealing member 80] The sealing member 80 has an annular ring 81 made of a metal such as steel, and an elastic portion 82 made of a material with a low elastic modulus such as synthetic rubber. The sealing member 80 is formed by, for example, baking and bonding the elastic portion 82 to the ring 81, and the ring 81 holds the elastic portion 82.

[0027] The ring 81 is annular, and has an inner diameter larger than the outer diameter of the rod 20, an outer diameter smaller than the inner diameter of the second end of the outer cylinder body 12, and an outer diameter equal to or larger than 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 comes into close contact with the entire outer circumferential surface of the rod 20. The elastic portion 82 also includes a dust lip 822 that is provided on the second side of the ring 81 and comes into close contact with the entire outer circumferential surface of the rod 20, thereby preventing dust from entering from outside.

[0029] The elastic portion 82 also has an outer circumferential seal portion 823 that protrudes from the outer circumferential portion of the ring 81 around the entire circumference in a direction inclined axially outward toward the first side. The outer circumferential seal 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 cylindrical body 12, thereby preventing hydraulic oil from leaking from a gap between the outer circumferential surface of the guide case 70 and the inner circumferential surface of the outer cylindrical body 12.

[0030] The elastic portion 82 also has a central seal portion 824 that protrudes from the inner circumferential portion of the ring 81 around the entire circumference in a direction inclined axially outward toward the first side. The central seal portion 824 comes into contact with the inner recess 721 of the outer cylindrical portion 72 of the guide case 70, thereby preventing the hydraulic oil or gas filled in the reservoir chamber R from moving inward via the flow path 75.

[0031] When assembling the shock absorber 2, after inserting the rod guide portion 60 into the outer cylindrical body 12, the seal member 80 is inserted into the outer cylindrical body 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 seal member 80 is held to the outer cylindrical body 12 by bending the second end of the outer cylindrical body 12 inward, a process known as roll crimping.

[0032] [Guide member 100] The guide member 100 has a cylindrical portion 110 disposed between the cylinder 11 and the outer cylinder body 12, and a connecting portion 120 connecting the cylindrical portion 110 and the cylinder 11. The guide member 100 can be formed, for example, by drawing a thin metal plate.

[0033] The cylindrical portion 110 is disposed closer to the outer cylindrical body 12 than the cylinder 11. For example, the gap G1 between the cylindrical portion 110 and the outer cylindrical body 12 can be 0.5 mm to 1 mm, and the gap G2 between the cylindrical portion 110 and the cylinder 11 can be 2 mm or more. The connecting portion 120 has a cylindrical fitting portion 121 that is fitted into the outer peripheral surface of the cylinder 11, and an inclined portion 122 that is inclined from a second end of the fitting portion 121 toward the second side and outward in the axial direction. 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 by the cylinder 11 by fitting the fitting portion 121 into the outer peripheral surface of the cylinder 11. For example, the fitting portion 121 can be press-fitted into the outer peripheral surface of the cylinder 11. Alternatively, the fitting portion 121 may be joined to the outer peripheral surface of the cylinder 11 by, for example, welding or adhesive.

[0035] The guide member 100 configured as described above is disposed at the end of the second side of the cylinder 11 so as not to come into contact with the hydraulic oil (hereinafter, sometimes referred to as "reserved oil Os") on the first side in the reservoir chamber R. In other words, even if the liquid surface of the hydraulic oil (reserved oil Os) in the reservoir chamber R becomes wavy due to, for example, the piston portion 30 moving at high speed, the guide member 100 is disposed at a position where the hydraulic oil in the reservoir chamber R will not come into contact with the guide member 100.

[0036] As described above, the shock absorber 2 includes the cylinder 11, the outer cylindrical body 12 that is disposed outside the cylinder 11 and covers the cylinder 11, and the piston portion 30 that defines hydraulic oil chambers (e.g., first oil chamber Y1, second oil chamber Y2) formed within the cylinder 11. The shock absorber 2 also includes a reservoir chamber R that is formed between the cylinder 11 and the outer cylindrical body 12 and is filled with hydraulic oil on the bottom side (e.g., first side, bottom cover 13 side) and with gas on the opening side (e.g., second side) of the cylinder 11. The shock absorber 2 also includes a rod guide portion 60 as an example of a support member that is disposed at the opening of the cylinder 11 and slidably supports the rod 20 that holds the piston portion 30 on one end side (e.g., first side), and that has a flow path 75 formed therein that returns hydraulic oil that has passed through a gap with the rod 20 and reached the opening side (e.g., second side) to the reservoir chamber R. The shock absorber 2 is also provided with a guide member 100 that is arranged in the reservoir chamber R and that comes into more contact with the outflow oil Of (see Figure 3), which is the hydraulic oil that has flowed out from the flow path 75, than with the stored oil Os, which is an example of the hydraulic oil in the reservoir chamber R, and that guides the outflow oil Of to the outer cylinder body 12.

[0037] FIG. 3 is a diagram illustrating an example of the operation of the shock absorber 2. FIG. 4 is a diagram illustrating an example of the operation of the shock absorber 2. In the shock absorber 2 configured as described above, outflow oil Of, which is hydraulic oil flowing out of the flow path 75, accumulates in a space S1 formed between the inside of the cylindrical portion 110 and the connecting portion 120 of the guide member 100 and the outer peripheral surface of the cylinder 11. Then, as shown in FIG. 4 , the outflow oil Of overflowing from the space S1 passes between the cylindrical portion 110 of the guide member 100 and the outer cylindrical body 12 and falls to the first side. Because the gap G1 between the cylindrical portion 110 and the outer cylindrical body 12 is narrow, the outflow oil Of overflowing from the space S1 falls while contacting the inner peripheral surface of the outer cylindrical body 12. Because the outer peripheral surface of the outer cylindrical body 12 is exposed to the outside air, the outflow oil Of is cooled by contact with the outer cylindrical body 12. The cooled outflow oil Of mixes with the hydraulic oil in the reservoir chamber R, thereby lowering the temperature of the hydraulic oil in the cylinder portion 10. As a result, it is possible to prevent the temperature of the hydraulic oil in the cylinder portion 10 from becoming too high and from exceeding a predetermined temperature. The predetermined temperature is determined taking into consideration the lifespan of the hydraulic oil and the temperature at which deterioration of the elastic portion 82 of the seal member 80 progresses.

[0038] Fig. 5 is a diagram showing an example of the operation of the shock absorber 2. As shown in Fig. 5, depending on the type of four-wheeled vehicle, when the four-wheeled vehicle is placed on a horizontal plane, the suspension device 1 may be attached to the four-wheeled vehicle in a state in which it is inclined with respect to a direction perpendicular to the horizontal plane (in a state in which it is inclined at an inclination angle θ (e.g., 30 degrees)).

[0039] In this way, 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 oil that flows out of the flow path 75 in the space S1, and can reliably bring the hydraulic oil that overflows from the space S1 into contact with the outer cylinder body 12.

[0040] Second Embodiment Fig. 6 is a diagram showing an example of a cross section of a guide member 200 according to a second embodiment. The guide member 200 according to the second embodiment differs from the guide member 100 according to the first embodiment in that it has a cylindrical portion 210 that corresponds to the cylindrical portion 110. Differences from the first embodiment will be described below. The same components in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0041] The cylindrical portion 210 has a cylindrical main body 211 and a protruding portion 212 that is provided at the second side end of the main body 211 and protrudes from the inside to the outside around the entire circumference. The gap G3 between the outer end of the protruding portion 212 and the outer cylinder body 12 is, for example, 0.5 mm to 1 mm, and the gap G4 between the main body 211 and the cylinder 11 is, for example, 1 mm or more. The protruding portion 212 may be formed so as to be perpendicular to the axial direction, or 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 oil flowing out from the flow path 75 (in other words, the outflow oil Of (see, for example, FIG. 3 )) falls onto the protruding portion 212 of the guide member 200, and then a portion of the hydraulic oil moves outward on the protruding portion 212 and falls between the protruding portion 212 and the outer cylinder body 12. Furthermore, a portion of the hydraulic oil that flows out from the flow path 75 and falls onto the protruding portion 212 of the guide member 200 moves inward on the protruding portion 212 and accumulates in a space S2 formed between the inside of the cylindrical portion 210 and the connecting portion 120 of the guide member 200 and the outer peripheral surface of the cylinder 11. The hydraulic oil that overflows from the space S2 then falls between the protruding portion 212 of the guide member 200 and the outer cylinder body 12. Because the gap G3 between the protruding portion 212 and the outer cylinder body 12 is narrow, the hydraulic oil that overflows from the space S2 tends to fall while coming into contact with the inner peripheral surface of the outer cylinder body 12. Since the outer peripheral surface of the outer cylinder 12 is exposed to the outside air, the hydraulic oil is cooled by contact with the outer cylinder 12. Therefore, by providing the guide member 200, the temperature of the hydraulic oil in the cylinder portion 10 can be prevented from becoming too high.

[0043] <Third embodiment> Figure 7 is a diagram showing an example of a cross section of a guide member 300 according to a 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 include a space S1 for storing hydraulic oil that has flowed out from the flow path 75. Differences from the first embodiment will be described below. The same components in the first and third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0044] The guide member 300 has a cylindrical fitting portion 310 that is fitted onto the outer peripheral surface of the cylinder 11, and a protruding portion 320 that protrudes from a first end of the fitting portion 310 toward the first side and outward along the entire circumference in a direction inclined with respect to the axial direction. A gap G5 between the outer end of the protruding portion 320 and the outer cylinder body 12 can be, for example, 0.5 mm to 1 mm.

[0045] In the guide member 300 configured as described above, hydraulic oil flowing out of the flow passage 75 (in other words, outflow oil Of (see, for example, FIG. 3 )) falls onto the protruding portion 320 of the guide member 300, moves along the protruding portion 320 to the first side and outward, and then falls through the gap between the protruding portion 320 and the outer cylinder 12. In this manner, the guide member 300 guides more hydraulic oil flowing out of the flow passage 75 to the outer cylinder 12 than to the cylinder 11. Furthermore, because the gap G5 between the protruding portion 320 and the outer cylinder 12 is narrow, hydraulic oil that falls through the gap between the protruding portion 320 and the outer cylinder 12 tends to fall while contacting the inner circumferential surface of the outer cylinder 12. Furthermore, because the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic oil is cooled by contact with the outer cylinder 12. Therefore, providing the guide member 300 can prevent the temperature of the hydraulic oil in the cylinder 10 from becoming too high.

[0046] Note that a plurality of notches recessed inward from the outer periphery may be formed in the circumferential direction at the outer end of the protruding portion 320 of the guide member 300. This makes it possible to prevent the temperature of the hydraulic oil in the cylinder portion 10 from becoming too low due to an increase in the amount of outflow oil Of contacting the inner circumferential surface of the outer cylinder body 12.

[0047] <Fourth embodiment> Figure 8 is a diagram showing an example of a cross section of a guide member 400 according to a 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 include a space S1 for storing hydraulic oil that has flowed out from the flow path 75. Differences from the first embodiment will be described below. The same components in the first and fourth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0048] The guide member 400 has a cylindrical fitting portion 410 that fits into the outer peripheral surface of the cylinder 11, and a protruding portion 420 that protrudes outward from the second-side end of the fitting portion 410 around the entire circumference. The protruding portion 420 may be formed so as to be perpendicular to the axial direction, or may be formed so as to be inclined axially toward the first side and outward. The gap G6 between the outer end of the protruding portion 420 and the outer cylinder body 12 can be, for example, 0.5 mm to 1 mm.

[0049] In the guide member 400 configured as described above, hydraulic oil flowing out of the flow path 75 falls onto the protruding portion 420 of the guide member 400, moves outward on the protruding portion 420, and falls between the protruding portion 420 and the outer cylindrical body 12. Because the gap G6 between the protruding portion 420 and the outer cylindrical body 12 is narrow, the hydraulic oil that falls between the protruding portion 420 and the outer cylindrical body 12 tends to fall while contacting the inner circumferential surface of the outer cylindrical body 12. Furthermore, because the outer circumferential surface of the outer cylindrical body 12 is exposed to the outside air, the hydraulic oil is cooled by contacting the outer cylindrical body 12. Therefore, providing the guide member 400 can prevent the temperature of the hydraulic oil from becoming too high.

[0050] The guide member 400 is molded separately from the cylinder 11, and then fitted or joined to the cylinder 11 to be integrated with the cylinder 11. However, this is not particularly limited to such an embodiment. 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 Fig. 9 is a diagram showing an example of a cross section of a guide member 500 according to a fifth embodiment. The guide member 500 according to the fifth embodiment differs from the guide member 400 according to the fourth embodiment in that the guide member 500 is integrated with the guide case 70 of the rod guide portion 60. Differences from the fourth embodiment will be described below. The same components in the fourth and fifth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

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

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

[0054] In the guide member 500 configured as described above, hydraulic oil flowing out of the flow path 75 falls onto the protruding portion 520 of the guide member 500, moves outward on the protruding portion 520, and falls between the protruding portion 520 and the outer cylindrical body 12. Because the gap G7 between the protruding portion 520 and the outer cylindrical body 12 is narrow, the hydraulic oil falling between the protruding portion 520 and the outer cylindrical body 12 tends to fall while contacting the inner circumferential surface of the outer cylindrical body 12. Furthermore, because the outer circumferential surface of the outer cylindrical body 12 is exposed to the outside air, the hydraulic oil is cooled by contacting the outer cylindrical body 12. Therefore, providing the guide member 500 can prevent the temperature of the hydraulic oil from becoming too high.

[0055] The guide member 500 is molded separately from the guide case 70, and then fitted into or joined to the guide case 70 to be integrated with the guide case 70. However, this is not particularly limited to such an embodiment. For example, the guide member 500 and the guide case 70 may be molded integrally. When the guide member 500 and the guide case 70 are molded integrally, the fitting portion 510 is not necessarily required, and only the protrusion 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 is a diagram showing an example of a cross section of a guide member 600 according to a 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. Differences from the fourth embodiment will be described below. The same reference numerals are used for the same components in the fourth and sixth embodiments, and detailed descriptions thereof will be omitted.

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

[0059] 10, the guide member 600 is held by being sandwiched between the second end of the cylinder 11 and the first end of the guide case 70. A gap G8 between the outer end of the guide member 600 and the outer cylinder body 12 can be, for example, 0.5 mm to 1 mm.

[0060] In the guide member 600 configured as described above, the hydraulic oil flowing out of the flow path 75 falls onto the guide member 600, moves outward on the guide member 600, and falls between the guide member 600 and the outer cylinder 12. Because the gap G8 between the guide member 600 and the outer cylinder 12 is narrow, the hydraulic oil falling between the guide member 600 and the outer cylinder 12 tends to fall while contacting the inner circumferential surface of the outer cylinder 12. Furthermore, because the outer circumferential surface of the outer cylinder 12 is exposed to the outside air, the hydraulic oil is cooled by contacting the outer cylinder 12. Therefore, providing the guide member 600 can prevent the temperature of the hydraulic oil from becoming too high.

[0061] Seventh Embodiment Fig. 11 is a diagram showing an example of a cross section of a guide member 700 according to a seventh embodiment. Fig. 12 is a diagram showing an example of a perspective view of the guide member 700 according to the seventh embodiment, as viewed 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 is formed in multiple circumferential and axial directions. Differences from the fourth embodiment will be described below. The same reference numerals are used for the same components in the fourth and seventh embodiments, and detailed description thereof will be omitted.

[0062] The guide member 700 has a fitting portion 710 that fits into the outer peripheral surface of the cylinder 11 and a protruding portion 720 that protrudes outward from the outer peripheral surface of the fitting portion 710. The protruding portion 720 may be, for example, rectangular and formed perpendicular to the axial direction. A plurality of protruding portions 720 are provided in the circumferential and axial directions. In the example shown in FIG. 12 , eight protruding portions 720 are formed in the circumferential direction (every 45 degrees) and in four axial stages. The eight protruding portions 720 provided in adjacent stages are shifted 22.5 degrees in the circumferential direction. When viewed in the axial direction, a protruding portion 720 of a stage provided on the first side of both circumferential ends of one protruding portion 720 is provided. The protruding portions 720 may be formed, for example, over an approximately 30-degree circumferential range.

[0063] In the guide member 700 configured as described above, the hydraulic oil flowing out of the flow passage 75 (in other words, the outflow oil Of (see FIG. 3 , for example)) falls onto the protruding portion 720, and then a portion of the hydraulic oil moves circumferentially on the protruding portion 720 and falls onto the protruding portion 720 of the step that is provided on the first side of the step on which the protruding portion 720 onto which the hydraulic oil flowed out of the flow passage 75 fell. Thereafter, the portion of the hydraulic oil that fell onto the protruding portion 720 falls onto the protruding portion 720 of the step that is provided on the first side of the step on which the protruding portion 720 is provided. In this way, the hydraulic oil flowing out of the flow passage 75 falls while moving circumferentially from the protruding portion 720 of the step that is provided on the second side to the protruding portion 720 of the step that is provided on the first side. Furthermore, the speed at which the hydraulic oil flowing out of the flow path 75 falls while moving over the multiple protrusions 720 is slower than the speed at which the hydraulic oil falls between the protrusions 720 and the outer cylinder body 12. In other words, the hydraulic oil flowing out of the flow path 75 falls slowly while moving over the multiple protrusions 720. As a result, the hydraulic oil falling while moving over the multiple protrusions 720 is cooled more than the hydraulic oil falling between the protrusions 720 and the outer cylinder body 12. Therefore, the guide member 700 can reliably prevent the temperature of the hydraulic oil from becoming too high.

[0064] <Modification of the Outer Cylinder Body 12> FIG. 13 is a diagram showing an example of a cross section of a shock absorber 2 employing an outer cylinder body 912 according to a modification. As shown in FIG. 13 , the outer cylinder body 912 according to the modification has an inner protrusion 913 at the second end that protrudes inward from the inner circumferential surface around the entire circumference. The inner protrusion 913 is provided at a location where the hydraulic oil flowing out of the flow path 75 (in other words, the outflow oil Of (see FIG. 3 , for example)) comes into contact with the hydraulic oil stored in the reservoir chamber R before mixing with the hydraulic oil. This allows a larger amount of hydraulic oil flowing out of the flow path 75 to come into contact with the outer cylinder body 912 for a longer period of time, thereby further reducing the temperature of the hydraulic oil in the cylinder portion 10. As a result, the temperature of the hydraulic oil in the cylinder portion 10 can be prevented from exceeding a predetermined temperature.

[0065] The inner protrusion 913 can be formed by, for example, bulging a cylindrical member, but may be formed by other methods. The outer cylinder 912 according to the modified example can be applied to any of the guide members 100 according to the first embodiment to the guide member 700 according to the seventh embodiment.

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

Claims

1. A cylinder; an outer cylinder body disposed outside the cylinder and covering the cylinder; a piston portion defining an oil chamber for hydraulic oil formed in the cylinder; a reservoir chamber formed between the cylinder and the outer cylindrical body, the reservoir chamber being filled with the hydraulic oil on the bottom side and with gas on the opening side of the cylinder; a support member that is disposed in the opening, slidably supports a rod that holds the piston portion at one end thereof, and has a flow path formed therein that returns the hydraulic oil that has passed through a gap with the rod and reached the opening side to the reservoir chamber; a guide member that is disposed in the reservoir chamber and has a cylindrical portion disposed between the cylinder and the outer cylindrical body, a connecting portion that connects the cylindrical portion and the cylinder, and a space that is formed by the cylindrical portion, the connecting portion, and the cylinder and that is capable of storing outflow oil that is the hydraulic oil that has flowed out of the flow path, and that guides the outflow oil that has overflowed from the space so that it falls while contacting the inner peripheral surface of the outer cylindrical body; A shock absorber comprising:

2. A cylinder, an outer cylinder body disposed outside the cylinder and covering the cylinder; a piston portion defining an oil chamber for hydraulic oil formed in the cylinder; a reservoir chamber formed between the cylinder and the outer cylindrical body, the bottom side of which is filled with hydraulic oil and the opening side of the cylinder with gas; a support member disposed at the opening, which slidably supports a rod that holds the piston portion at one end thereof, and which has a flow path formed therein that returns the hydraulic oil that has passed through a gap with the rod and reached the opening side to the reservoir chamber; a guide member that is disposed in the reservoir chamber and has a cylindrical fitting portion that is fitted onto the outer peripheral surface of the cylinder, and a protruding portion that protrudes from the piston-side end of the fitting portion toward the piston and outward in a direction inclined with respect to the axial direction, and that guides the outflowing oil, which is the hydraulic oil that has flowed out of the flow path, so that it falls while contacting the inner peripheral surface of the outer cylindrical body; A shock absorber comprising:

3. The guide member is disposed at a position where it does not come into contact with the hydraulic oil in the reservoir chamber. The shock absorber according to claim 1 .

4. The cylindrical portion of the guide member has a protrusion that protrudes from the outer periphery of the cylinder toward the outer cylindrical body. 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 arranged in a position where it does not come into contact with the hydraulic oil in the reservoir chamber. 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 shock absorber according to any one of claims 1 to 7; a spring disposed around the shock absorber; A suspension device comprising: