shock absorbers

Abstract

Shock absorber (1), comprising: a cylinder (2) containing a hydraulic fluid densely packed therein; a piston (18) which is inserted smoothly and precisely into the cylinder (2) and defines a rod-side chamber (19) and a bottom-side chamber (20) in the cylinder (2); a piston rod (21) comprising an end face section which is fixed to the piston (18) in the cylinder (2) and an opposite end face section which extends out of the cylinder (2) via a rod guide (22); a damping force generation mechanism (41, 42, 197) designed to generate a damping force by moving the piston (18); a cylindrical housing (131, 131A, 131C) with a base; a separating disc (134, 134A, 134C) which is movable relative to the housing (131, 131A, 131C) and forms an inner housing chamber (171, 171A, 171C) between a bottom section (141, 141A) of the housing (131, 131A, 131C) and the separating disc (134, 134A, 134C); and a ring-shaped opposing element (139, 139A, 139C) which is provided on a side of the cutting disc (134, 134A, 134C) opposite the bottom section (141, 141A), opposite the cutting disc (134, 134A, 134C), wherein the inner circumferences of the housing (131, 131A, 131C) and the opposite element (139, 139A, 139C) are fixed by a pin element (194A, 194B, 194C) passing through them, wherein a projecting section (143, 252, 252C) is formed on the bottom section (141, 141A) of the housing (131, 131A, 131C) or the opposite element (139, 139A, 139C), wherein the projecting section (143, 252, 252C) projects towards the cutting disc (134, 134A, 134C) and is designed to restrict movement of the cutting disc (134, 134A, 134C), and wherein a sealing section (158, 158A) is provided on a projecting section (143, 252, 252C) of the cutting disc (134, 134A, 134C), wherein the sealing section (158, 158A) is designed to seal between an outer circumference of the cutting disc (134, 134A, 134C) and the inner circumference of the housing (131, 131A, 131C), wherein an elastic section (159, 159A) is provided between a surface of the separating disc (134, 134A, 134C) which is opposite a surface of the separating disc (134, 134A, 134C) on which the sealing section (158, 158A) is provided and the opposite element (139, 139A, 139C) or the bottom section (141, 141A) of the housing (131, 131A, 131C).

Description

Technical field

[0001] The present invention relates to a shock absorber. Current state of the art

[0002] Some shock absorbers are fitted with a rod acceleration reduction mechanism on a bottom valve to prevent or reduce the formation of abnormal noise (see, for example, JP 2011 - 247 371 A).

[0003] DE 10 2014 205 302 B4 describes a shock absorber that generates a damping force by controlling a hydraulic fluid flow during compression of a piston rod.

[0004] DE 10 2011 090 032 A1 describes shock absorbers with damping force control, which are suitable, for example, for damping vibrations of vehicles. Description of the invention: Technical problem

[0005] Then it is necessary to reduce the size of the shock absorbers.

[0006] Therefore, one object of the present invention, as defined by the attached claims, is to provide a shock absorber whose size can be reduced. Solution to the problem

[0007] To solve the problem described above, the present invention comprises a cylindrical housing with a base, a disk rotatably mounted relative to the housing and forming an inner chamber between a base section of the housing and the disk, and an annular opposing element located on a side of the disk opposite the base section. The inner circumferential surfaces of the housing and the opposing element are fixed by a pin element passing through them. A projecting section is formed on the base section of the housing or on the opposing element. The projecting section extends toward the disk and is designed to restrict movement of the disk. A sealing section is provided on the side of the disk where the projecting section is located.The sealing section is designed to seal between an outer circumference of the disc and an inner circumference of the housing.

[0008] In a first aspect of the invention, it is provided that an elastic section is provided between a surface of the disc that is opposite a surface of the disc on which the sealing section is provided and the opposite element or the bottom section of the housing.

[0009] In a first aspect of the invention, it is provided that an annular space is formed between the disc and the housing and that the sealing section is provided in such a way that it is firmly attached to both surfaces of the disc over the space. Advantageous effects of the invention

[0010] According to the present invention, the size of the shock absorber can be reduced. Brief description of the drawings Fig. Figure 1 is a cross-sectional view illustrating a shock absorber according to a first embodiment of the present invention. Fig. Figure 2 is a partial cross-sectional view of a close vicinity of a piston in the shock absorber according to the first embodiment of the present invention. Fig. Figure 3 is a partial cross-sectional view of a near environment of the piston, a damping force generation mechanism and a damping force adjustment mechanism, illustrating the shock absorber according to the first embodiment of the present invention. Fig. Figure 4 illustrates a characteristic curve that conceptually indicates a relationship between a damping force and a piston speed of the shock absorber according to the first embodiment of the present invention. Fig. Figure 5 is a partial cross-sectional view of a close vicinity of a bottom valve and a damping force adjustment mechanism illustrating a shock absorber according to a second embodiment of the present invention. Fig. Figure 6 is a partial cross-sectional view of a close environment of the damping force adjustment mechanism, illustrating the shock absorber according to the second embodiment of the present invention. Fig. Figure 7 illustrates a characteristic curve that conceptually indicates a relationship between the damping force and the piston speed of the shock absorber according to the second embodiment of the present invention. Fig. Figure 8 is a partial cross-sectional view of a close environment of a damping force adjustment mechanism illustrating a shock absorber according to a third embodiment of the present invention. Fig. Figure 9 is a partial cross-sectional view of a close environment of a damping force adjustment mechanism illustrating a shock absorber according to a fourth embodiment of the present invention. Description of embodiments [First embodiment]

[0011] A first embodiment of the present invention is described with reference to Fig. 1, Fig. 2, Fig. 3 to Fig. 4 described. In the following description of the first embodiment, an upper side of the drawing is referred to as an upper side and a lower side of the drawing is referred to as a lower side, to simplify the description.

[0012] As in Fig. As illustrated in Figure 1, a shock absorber 1 according to the first embodiment is a so-called twin-tube hydraulic shock absorber and includes a cylinder 2 containing a densely packed hydraulic fluid. The cylinder 2 comprises a cylindrical inner tube 3, a cylindrical outer tube with a base 4, and a cover 5. The outer tube 4 has a larger diameter than the inner tube 3 and is arranged concentrically on one outer circumferential side so that it covers the inner tube 3. The cover 5 covers an upper opening of the outer tube 4. A reservoir chamber 6 is formed between the inner tube 3 and the outer tube 4.

[0013] The outer tube 4 includes a cylindrical drum element 11 and a bottom element 12. The bottom element 12 is precisely fixed to one side of a lower section of the drum element 11 and closes off a lower section of the drum element 11. A mounting eye 13 is fixed to the bottom element 12 on an outer side opposite the drum element 11.

[0014] The cover 5 comprises a tubular section 15 and an inner flanged section 16. The inner flanged section 16 extends radially inward from an upper end face of the tubular section 15. The cover 5 is positioned over the drum element 11 such that the inner flanged section 16 covers an opening at the upper end of the drum element 11, and the tubular section 15 covers an outer circumferential surface of the drum element 11. In this position, the cover 5 is fixed to the drum element 11 by a radially inwardly compressed portion of the tubular section 15.

[0015] A piston 18 is inserted into the inner tube 3 of the cylinder 2 in a sliding manner, fitting precisely into place. The piston 18 defines an upper chamber 19 and a lower chamber 20 within the inner tube 3. The oil fluid, as the hydraulic fluid, is tightly contained in the upper chamber 19 and the lower chamber 20 within the inner tube 3, and the oil fluid, as the hydraulic fluid, and gas are tightly contained in the reservoir chamber 6 between the inner tube 3 and the outer tube 4.

[0016] One end face of a piston rod 21 is inserted into the cylinder 2, and the piston 18 is coupled to this end face. In other words, this end face of the piston rod 21 is fixed to the piston 18 within the cylinder 2. The piston 18 and the piston rod 21 move integrally. During an expansion stroke, in which the piston rod 21 increases the amount protruding from the cylinder 2, the piston 18 moves toward one side of the upper chamber 19. During a compression stroke, in which the piston rod 21 decreases the amount protruding from the cylinder 2, the piston 18 moves toward one side of the lower chamber 20. The upper chamber 19 is a rod-side chamber located on one side of the piston rod 21 of the piston 18, and the lower chamber 20 is a bottom-side chamber located on one side of a bottom element 12, i.e., the bottom of the piston 18.

[0017] A rod guide 22 is attached to the opening sides at the upper end of the inner tube 3 and the outer tube 4, and a sealing element 23 is attached to the outer tube 4 on an upper side which is an outer surface of the cylinder 2 with respect to the rod guide 22. A friction element 24 is provided between the rod guide 22 and the sealing element 23. The rod guide 22, the sealing element 23, and the friction element 24 are all annular, and the piston rod 21 is slidably inserted into the respective inner surfaces of this rod guide 22, the friction element 24, and the sealing element 23, so that it extends from the cylinder 2. In other words, one end face of the piston rod 21 is fixed to the piston 18 in the cylinder 2, and the other end face projects out of the cylinder 2 over the rod guide 22 and the sealing element 23.

[0018] The rod guide 22 supports the piston rod 21 axially, while restricting its radial movement, and guides the movement of the piston rod 21. The sealing element 23 is in close contact with the outer tube 4 at its outer circumferential section and is in sliding contact with an outer circumferential section of the axially movable piston rod 21 at its inner circumferential section, thereby preventing the oil fluid in the inner tube 3 and the high-pressure gas and oil fluid in the reservoir chamber 6 from escaping into the outer tube 4. The friction element 24 is in sliding contact with the outer circumferential section of the piston rod 21 at its inner circumferential section, thereby generating frictional resistance on the piston rod 21. The friction element 24 is not intended for sealing purposes.

[0019] An outer circumferential section of the rod guide 22 has a stepped shape with a lower section and an upper section, the diameter of which is larger than that of the lower section. Its lower section, with its smaller diameter, is attached to an inner circumferential section of the upper end of the inner tube 3, and its upper section, with its larger diameter, is attached to an inner circumferential section of the upper section of the outer tube 4. A bottom valve 25, which defines the lower chamber 20 and the reservoir chamber 6, is mounted on the bottom element 12 of the outer tube 4, and an inner circumferential section of a lower end of the inner tube 3 is attached to the bottom valve 25. The upper end section of the outer tube 4 is radially compressed inwards at a portion not shown, and the compressed section and the rod guide 22 sandwich the sealing element 23 between them.

[0020] The piston rod 21 comprises a main shaft section 27 and a mounting shaft section 28 of a smaller diameter than the main shaft section 27. The mounting shaft section 28 is arranged in the cylinder 2, and the piston 18 and the like are attached to it. An end section of the main shaft section 27 on the side of the mounting shaft section 28 forms a shaft step section 29, which extends in a direction orthogonal to an axis. An axially extending through groove 30 is formed at an intermediate axial position on an outer circumferential section of the mounting shaft section 28, and a threaded bolt 31 is formed at a distal end position, which is axially opposite the main shaft section 27.The through groove 30 is formed such that it has a rectangular shape, a square shape and a D-shaped shape in a cross-section along a plane orthogonal to a central axis line of the piston rod 21.

[0021] A stop element 32 and a buffer 33, both annular, are provided on the piston rod 21 at a section of the main shaft section 27 between the piston 18 and the rod guide 22. The piston rod 21 passes through an inner circumferential face of the stop element 32, and the stop element 32 is fixed by upsetting in a radially inwardly recessed fixing groove 34 of the main shaft section 27. The piston rod 21 also passes through the interior of the buffer 33, and the buffer 33 is arranged between the stop element 32 and the rod guide 22.

[0022] The shock absorber 1 is mounted, for example, such that the section of the piston rod 21 protruding from the cylinder 2 is located at the top and supported by a vehicle body, and the mounting eye 13 is located on the side of the cylinder 2 at the bottom and connected to a wheel side. Conversely, the shock absorber 1 can be mounted such that the side of the cylinder 2 is supported by the vehicle body and the piston rod 21 is connected to the wheel side. When the wheel vibrates during driving, the positions of the cylinder 2 and the piston rod 21 change relative to each other in accordance with this vibration; however, this change is eliminated or reduced by fluid resistance in a fluid passage formed in the piston 18 and / or the piston rod 21.As described in detail below, the fluid passage formed in the piston 18 and / or the piston rod 21 is designed such that the fluid resistance within it varies depending on the speed and amplitude of the vibration, and ride comfort can be improved by damping the vibration. In addition to the vibration generated by the wheel, an inertial force and a centrifugal force are also applied between the cylinder 2 and the piston rod 21 described above. These forces are generated on the vehicle body according to the vehicle's direction of travel. For example, the centrifugal force on the vehicle body is generated by changing the direction of travel through steering wheel input, and a force based on this centrifugal force is applied between the cylinder 2 and the piston rod 21 described above.As described below, the shock absorber 1 has excellent characteristics against vibration based on the force generated on the vehicle body according to the vehicle's movement, and can achieve high stability during the vehicle's movement.

[0023] As in Fig. As illustrated in Figure 2, the piston 18 comprises a metallic piston body 35 and an annular sliding element 36 made of synthetic resin. The piston body 35 is supported by the piston rod 21. The sliding element 36 is integrally formed on an outer circumferential surface of the piston body 35 and slides within the inner tube 3.

[0024] A plurality of through holes 38 (only one hole 38 is in Fig. 2 shown, since Fig. 2 is presented as a cross-sectional view) and a plurality of through holes 39 (only one hole 39 is in Fig. 2 shown, since Fig. 2 (presented as a cross-sectional view) are provided in the piston main body 35. The majority of through-holes 38 form passages in their interior, which establish a connection between the upper chamber 19 and the lower chamber 20 and allow the oil fluid to flow from the upper chamber 19 towards the lower chamber 20 during the movement of the piston 18 towards the side of the upper chamber 19, i.e., the expansion stroke.

[0025] The plurality of through-holes 39 form passages within them that allow the oil fluid to flow from the lower chamber 20 towards the upper chamber 19 during the movement of the piston 18 towards the side of the lower chamber 20, i.e., the compression stroke. In other words, the passages in the plurality of through-holes 38 and the passages in the plurality of through-holes 39 establish the connection such that they allow the oil fluid, which is the hydraulic fluid, to flow between the upper chamber 19 and the lower chamber 20 due to the movement of the piston 18. The through-holes 38 are formed at equal intervals and sandwich a through-hole 39 between them in the circumferential direction, with one axial side (an upper side) facing the other. Fig. 2) and the other axial side (a lower side in Fig. 2) of the piston 18 are open on a radially outer side or a radially inner side.

[0026] As in Fig. As shown in Figure 3, a damping force generation mechanism 41 is provided with respect to these through-holes 38, which are half the size of the through-holes. The damping force generation mechanism 41 generates a damping force through the movement of the piston 18. The damping force generation mechanism 41 is arranged on the side of the lower chamber 20, which is an axial end face of the piston 18, and is attached to the piston rod 21. The through-holes 38 form expansion-side passages in their interior, through which the oil fluid passes when the piston rod 21 and the piston 18 move towards the expansion side (an upper side in Fig. 3) move, and the damping force generation mechanism 41 provided for this purpose serves as an expansion-side damping force generation mechanism, which generates a damping force by preventing or reducing the flow of oil fluid in the passages in the expansion-side through-holes 38. A damping force adjustment mechanism 43 is attached to the mounting shaft section 28 of the piston rod 21 adjacent to a side of the damping force generation mechanism 41 opposite the piston 18. The damping force adjustment mechanism 43 makes the damping force variable depending on a frequency of a reciprocating movement of the piston 18 (hereinafter referred to as a piston frequency) during the expansion stroke.

[0027] Furthermore, as in Fig. As shown in Figure 2, the through holes 39, which constitute the remaining half of the through holes, are formed at equal intervals and sandwich a through hole 38 between them in the circumferential direction, and the other axial side (the lower side in Fig. 2) and one axial side (the upper side in Fig. 2) of the piston 18 are open on the radially outer side or the radially inner side.

[0028] Furthermore, with respect to these through-holes 39, which constitute the remaining half of the through-holes, a damping force generation mechanism 42 is provided, which generates a damping force. The damping force generation mechanism 42 is arranged on the side of the upper chamber 19 in the axial direction, which is the other axial end face of the piston 18, and is attached to the piston rod 21. The through-holes 39 form compression-side passages in their interior, through which the oil fluid passes when the piston rod 21 and the piston 18 move towards the compression side (the lower side in Fig. 2) move, and the damping force generation mechanism 42 provided for this purpose serves as a compression-side damping force generation mechanism which generates a damping force by preventing or reducing the flow of the oil fluid in the passages in the compression-side through-holes 39.

[0029] The piston body 35 generally has a disc-shaped form, and a fitting hole 45 is formed in its radial center. The fitting hole 45 extends axially through the piston body and serves to insert the mounting shaft section 28 of the piston rod 21. An axial end section of the piston body 35 on the side of the lower chamber 20 supports an inner circumferential side of the damping force generation mechanism 41 at its section between the fitting hole 45 and the through holes 38. An axial end section of the piston body 35 on the side of the upper chamber 19 supports an inner circumferential side of the damping force generation mechanism 42 at its section between the fitting hole 45 and the through holes 39.

[0030] An annular valve seat section 47, which is part of the damping force generation mechanism 41, is formed on the axial end section of the piston main body 35 on the side of the lower chamber 20, on a radially outer side relative to the openings of the through holes 38 on the side of the lower chamber 20. Furthermore, an annular valve seat section 49, which is part of the damping force generation mechanism 42, is formed on the axial end section of the piston main body 35 on the side of the upper chamber 19, on a radially outer side relative to the openings of the through holes 39 on the side of the upper chamber 19. The locating hole 45 of the piston main body 35 includes a small-diameter hole section 301 and a large-diameter hole section 302. The small-diameter hole section 301 serves for the insertion of the mounting shaft section 28 of the piston rod 21 and is located on one side of the valve seat section 49 in the axial direction.The large-diameter hole section 302 is located on one side of the valve seat section 47 in the axial direction with respect to the small-diameter hole section 301. The large-diameter hole section 302 of the piston main body 35 is formed on one side of the seat element 55, opposite the piston rod 21.

[0031] A side of the piston main body 35 opposite the locating hole 45 of the valve seat section 47 has a stepped shape located at a lower axial height than the valve seat section 47, and openings of the compression-side through-holes 39 on the side of the lower chamber 20 are arranged on this stepped section. Similarly, a side of the piston main body 35 opposite the locating hole 45 of the valve seat section 49 has a stepped shape located at a lower axial height than the valve seat section 49, and openings of the expansion-side through-holes 38 on the side of the upper chamber 19 are arranged on this stepped section.

[0032] As in Fig. As illustrated in Figure 3, the expansion-side damping force generation mechanism 41 is a pressure-control type valve mechanism and comprises a single disk 51, a single main valve 52, a single disk 53, a single disk 54, a single seat element 55, a single disk 56, a single disk 57, a single disk 58, a single disk 59, a single disk 60, a single disk 61, and a single disk 62 in that order, starting from the side of the piston 18 in the axial direction. The disks 51, 53, 54, and 56 to 62, as well as the seat element 55, are made of metal. All disks 51, 53, 54, and 56 to 62 have a perforated, circular plate-like shape with a constant thickness into which the mounting shaft section 28 of the piston rod 21 can be inserted.Both the main valve 52 and the seat element 55 have an annular shape into which the mounting shaft section 28 of the piston rod 21 can be inserted.

[0033] The seat element 55 comprises a perforated, disc-shaped base section 71, a cylindrical inner section 72, and a cylindrical outer section 73. The base section 71 extends along the direction orthogonal to the axis. The inner cylindrical section 72 is formed on an inner circumferential side of the base section 71 and extends along the axial direction. The outer cylindrical section 73 is formed on an outer circumferential side of the base section 71 and extends along the axial direction. The base section 71 is offset from the inner cylindrical section 72 and the outer cylindrical section 73 in the direction of an axial side. An axially extending through-hole 74 is formed through the base section 71.In the inner cylindrical section 72, a small-diameter hole section 75 is formed on one side of the bottom section 71 in the axial direction, and a large-diameter hole section 76 is formed on the opposite side of the bottom section 71 in the axial direction. The small-diameter hole section 75 allows the mounting shaft section 28 of the piston rod 21 to be attached to it. The large-diameter hole section 76 has a larger diameter than the small-diameter hole section 75.

[0034] An end section of the inner cylindrical section 72 of the seat element 55, on the side of the base section 71 in the axial direction, supports an inner circumferential side of the disk 56, and an end section of the inner cylindrical section 72, on the side opposite the base section 71 in the axial direction, supports an inner circumferential side of the disk 54. An end section of the outer cylindrical section 73 of the seat element 55, on the side of the base section 71 in the axial direction, forms an annular valve seat section 79. The interior of the seat element 55, including the through-hole 74, forms a pilot chamber 80. The pilot chamber 80 applies pressure to the main valve 52 in one direction towards the piston 18.

[0035] The disc 51 has an outer diameter that is smaller than the inner diameter of the valve seat section 47. The main valve 52 includes a metallic disc 85 and a rubber sealing element 86, which is fixedly attached to the disc 85. The disc 85 has a perforated, circular plate-like shape of constant thickness into which the mounting shaft section 28 of the piston rod 21 can be inserted, and has an outer diameter that is slightly larger than the outer diameter of the valve seat section 47. The sealing element 86 is fixedly attached to an outer circumferential side of the disc 85 opposite the piston 18 and has an annular shape.

[0036] An axially extending through-bore 87 is formed through the disk 51 on a radially outer side of the piston main body 35 with respect to the through-holes 38. The disk 85 can rest on the valve seat section 47 of the piston 18. The main valve 52 is located between the passages in the through-holes 38 provided in the piston 18 and the pilot chamber 80 provided in the seat element 55, and generates a damping force by preventing or reducing the flow of oil fluid towards the expansion side caused by the sliding movement of the piston 18. This main valve 52 is a disc valve.

[0037] The sealing element 86 seals a space between the main valve 52 and the outer cylindrical section 73 by contacting an inner circumferential surface of the outer cylindrical section 73 of the seat element 55 over its entire circumference. Therefore, the pilot chamber 80 described above, located between the main valve 52 and the seat element 55, exerts an internal pressure on the main valve 52 in the direction towards the piston 18, i.e., in a valve closing direction, to cause the disk 85 to rest on the valve seat section 47. The through-bore 87 of the disk 51, the large-diameter hole section 302 of the piston 18, the through-groove 30 of the piston rod 21, and a recess 91 of the disk 54 serve as passages for introducing the oil fluid from the upper chamber 19 in the cylinder 2, via the passages in the through-holes 38, into the pilot chamber 80.The main valve 52 is a pilot-type damping valve incorporating the pilot chamber 80. When the disk 85 is separated from the valve seat section 47 of the piston 18 and opened, the oil fluid flows from the passages in the through-holes 38 through a passage 88, which extends radially between the piston 18 and the outer cylindrical section 73 of the seat element 55, towards the lower chamber 20. In other words, the expansion-side damping force generation mechanism 41 directs a portion of the oil fluid flow through a passage in the through-hole 87 of the disk 51, the large-diameter hole section 302 of the piston 18, the through-groove 30 of the piston rod 21, and the recess 91 of the disk 54 into the pilot chamber 80 and controls the opening of the main valve 52 based on the pressure in the pilot chamber 80.

[0038] The disk 53 has an outer diameter that is smaller than the outer diameter of the inner cylindrical section 72 and larger than the inner diameter of the large-diameter hole section 76. The disk 54 is an ordinary component made of the same material and with the same shape as the disk 51, and includes the recess 91 formed on one of its inner circumferential faces. The recess 91 extends radially over a section of the inner cylindrical section 72 that contacts the disk 54, and the passage in the large-diameter hole section 76 of the seat element 55 and the pilot chamber 80 are in constant communication with each other via a passage in the recess 91.

[0039] The disc 56 has an outer diameter that is smaller than the inner diameter of the valve seat section 79 of the seat element 55. The disc 57 has an outer diameter that is slightly larger than the outer diameter of the valve seat section 79 and is designed to rest on the valve seat section 79. The disc 57 includes a recess 93 on one of its outer circumferential sides, and the recess 93 extends radially over the valve seat section 79.

[0040] Disc 58, disc 59, and disc 60 have outer diameters equal to the outer diameter of disc 57. Disc 61 has an outer diameter smaller than the outer diameter of disc 60. Disc 62 has an outer diameter larger than the outer diameter of disc 61 but smaller than the outer diameter of disc 60.

[0041] The discs 57 to 60 form a disc valve 99, which rests on and can be separated from the valve seat section 79. This valve prevents or reduces the flow of oil fluid between the pilot chamber 80 and the lower chamber 20, while simultaneously establishing a connection between them by separating from the valve seat section 79. The pilot chamber 80 is formed by being surrounded by the main valve 52, the seat element 55, and the disc valve 99. The recess 93 of the disc 57 forms a fixed opening 100, which maintains a connection between the pilot chamber 80 and the lower chamber 20 even when the disc 57 is in contact with the valve seat section 79. The disc 62 prevents or reduces deformation of the disc valve 99 by bearing against the disc 60 in an opening direction at the moment of deformation of the disc valve 99.

[0042] An expansion-side first passage 101, through which the oil fluid flows out of the upper chamber 19 towards the lower chamber 20 due to the movement of the piston 18 during the expansion stroke, is formed by the passages in the expansion-side through-holes 38 provided in the piston 18, the space between the main valve 52 and the valve seat section 47 when the valve is open, the passage 88 extending radially between the piston 18 and the outer cylindrical section 73, the through-bore 87 provided by the disk 51, the large-diameter hole section 302 of the piston 18, the large-diameter hole section 76 of the seat element 55 and the recess 91 of the disk 54, the pilot chamber 80, the fixed opening 100 and the space between the disk valve 99 and the valve seat section 79 when the valve is open.The expansion-side damping force generation mechanism 41 is arranged in this expansion-side first passage 101 and generates the damping force.

[0043] As in Fig. As illustrated in Figure 2, the compression-side damping force generation mechanism 42 comprises a single disk 111, a single disk 112, a plurality of disks 113, a plurality of disks 114, a single disk 115, a single disk 116, and a single annular element 117 in that order, starting from the side of the piston 18 in the axial direction. The disks 111 to 116 and the annular element 117 are made of metal, and they all have a perforated, circular plate-like shape with a constant thickness into which the mounting shaft section 28 of the piston rod 21 can be inserted.

[0044] The disc 111 has an outer diameter that is smaller than the inner diameter of the valve seat section 49 of the piston 18. The disc 112 has an outer diameter that is slightly larger than the outer diameter of the valve seat section 49 of the piston 18 and is designed to bear on the valve seat section 49. The disc 112 includes a recess 121 formed on one of its outer circumferential faces, and the recess 121 extends radially over the valve seat section 49.

[0045] The majority of disks 113 are ordinary components made of the same material and have the same shape, and their outer diameter is equal to the outer diameter of disk 112. The majority of disks 114 are ordinary components made of the same material and have the same shape, and their outer diameter is smaller than the outer diameter of disks 113. Disk 115 has an outer diameter that is smaller than the outer diameter of disks 114. Disk 116 has an outer diameter that is larger than the diameter of disks 114 and smaller than the outer diameter of disks 113. The annular element 117 has an outer diameter that is smaller than the outer diameter of disk 116 and is thicker and stiffer than disks 111 to 116. This annular element 117 is located in contact with the shaft step section 29 of the piston rod 21.

[0046] The discs 112 to 114 form a disc valve 122, which rests on and can be separated from the valve seat section 49. This valve prevents or reduces the flow of oil fluid between the upper chamber 19 and the lower chamber 20, while simultaneously opening the passages in the through-holes 39 to the upper chamber 19 by separating it from the valve seat section 49. The recess 121 of the disc 112 forms a fixed opening 123, which maintains communication between the upper chamber 19 and the lower chamber 20 even when the disc 112 is in contact with the valve seat section 49. The annular element 117 limits deformation of the disc valve 122 in an opening direction that is greater than or equal to a predetermined amount.

[0047] A compression-side first passage 102, through which the oil fluid flows from the lower chamber 20 towards the upper chamber 19 due to the movement of the piston 18 during the compression stroke, is formed by the passages in the compression-side through-holes 39 provided in the piston 18, the fixed opening 23, and the space between the disc valve 122 and the valve seat section 49 when the valve is open. The compression-side damping force generation mechanism 42 is provided in this compression-side first passage 102 and generates the damping force.

[0048] In the present embodiment, the expansion-side disc valve 99 and the compression-side disc valve 122, which are located in Fig. Figure 3 is shown, described with reference to the example in which they are both disc valves clamped at their inner circumference, but they are not limited to this and can be any mechanism capable of generating the damping force. For example, these valves can be poppet valves, where a disc valve is preloaded using a coil spring, or they can be poppet valves.

[0049] The damping force adjustment mechanism 43 comprises a single cylindrical housing with a base 131, a single disk 132, a single disk 133, a single separating disk 134, a plurality of disks 135, and an annular opposing element 139 opposite the separating disk 134, in that order starting from the side of the damping force generation mechanism 41 in the axial direction. The housing 131, the disks 132, 133, and 135, and the opposing element 139 are made of metal. The disks 132, 133, and 135 all have a perforated, circular plate-like shape with a constant thickness into which the mounting shaft section 28 of the piston rod 21 can be inserted. Both the housing 131 and the opposing element 139 have an annular shape into which the mounting shaft section 28 of the piston rod 21 can be inserted.

[0050] The opposing element 139 is annular and, together with the housing 131, forms a tubular housing element 140 by being attached to the housing 131. The housing 131 includes a perforated, disc-like bottom section 141, a cylindrical inner section 142, and a cylindrical projecting section 143. The bottom section 141 extends along the direction orthogonal to the axis. The inner cylindrical section 142 is formed on an inner circumferential side of the bottom section 141 and extends along the axial direction. The projecting section 143 is formed on an outer circumferential side of the bottom section 141 with respect to the inner cylindrical section 142 and extends along the axial direction.The inner cylindrical section 142 projects from the base section 141 in both axial directions, and the projecting section 143 projects from the base section 141 only in one axial direction. Within the inner cylindrical section 142, a small-diameter hole section 145 is formed on one side opposite the axial direction in which the projecting section 143 projects, and a large-diameter hole section 146 is formed on one side of the projecting section 143 in the axial direction. The small-diameter hole section 145 allows the mounting shaft section 28 of the piston rod 21 to be attached to it. The large-diameter hole section 146 has a larger diameter than the small-diameter hole section 145.Furthermore, a cylindrical tubular section 166 is formed on an outer circumferential side of the bottom section 141 with respect to the projecting section 143.

[0051] The inner cylindrical section 142 of the housing 131 supports an inner circumferential side of the disk 62 with one end section on one side of the small-diameter hole section 145 in the axial direction, and supports an inner circumferential side of the disk 132 with its other end section on one side of the large-diameter hole section 146 in the axial direction. The projecting section 143 of the housing 131 extends towards the cutting disk 134 and restricts movement of the cutting disk 134 beyond that in the direction of one side of the base section 141 by bearing against the cutting disk 134. The projecting section 143 supports an outer circumferential side of the cutting disk 134 with one end section on a projecting distal side.Furthermore, the projecting section 143 includes a circumferentially partially formed recess 303, and a radially inner side and a radially outer side of the projecting section 143 in the housing 131 are in constant communication with each other.

[0052] The disk 132 has an outer diameter that is larger than the portion of the inner cylindrical section 142 in contact with the disk 132 and smaller than the inner diameter of the projecting section 143. The disk 132 includes a recess 151 formed on one of its inner circumferential faces. The recess 151 extends radially over the portion of the inner cylindrical section 142 that is in contact with the disk 132. The disk 133 has an outer diameter that is smaller than the outer diameter of the disk 132.

[0053] The separating disc 134 comprises a metallic disc 155 and a rubber sealing element 156, which is fixedly attached to an outer circumferential side of the disc 155 and is designed to be elastically deformable. The disc 155 has a perforated, circular plate-like shape with a constant thickness, which can be spaced apart from the inner disc 133 and is thinner than the disc 133. The disc 155 has an outer diameter that is larger than the outer diameter of the projecting section 143 of the housing 131.

[0054] The sealing element 156 has an annular shape and is fixedly attached to the outer circumferential side of the disc 155. The sealing element 156 comprises an annular sealing section 158 and an annular elastic section 159. The sealing section 158 projects axially from the disc 155 towards a side opposite the opposing element 139. The elastic section 159 projects axially from the disc 155 towards a side of the opposing element 139. Furthermore, an annular space is created between the disc 155 and the housing 131, and the sealing element 156 secures the sealing section 158 and the elastic section 159 to both surfaces of the disc 155 via this space. The use of such a design makes it possible to easily and securely attach the sealing element 156 to the disc 155.The inner diameter of the sealing section 158 is minimized at one end section on one side of the disc 155, and this inner diameter is slightly larger than the outer diameter of the projecting section 143. This design allows the disc 155 of the cutting disc 134 to abut the projecting section 143 of the housing 131. A radial groove 161 is formed on the elastic section 159. The radial groove 161 is open on one side opposite the disc 155 and extends radially. Due to this radial groove 161, the disc 155 of the cutting disc 134 abuts the projecting section 143 when the pressure in the lower chamber 20 exceeds a pressure in a variable chamber 171 described below.Since the recess 303 is provided on the projecting section 143, pressure-bearing areas on one side of the disk 155, on which the sealing section 158 is provided, and on the other side of the disk 155, on which the elastic section 159 is provided, are approximately identical.

[0055] The disc 135 has an outer diameter that is larger than the inner diameter of the disc 155 of the cutting disc 134. Due to this design, an inner circumferential side of the cutting disc 134 is movably supported between the disc 132 and the disc 135 within a region corresponding to the axial length of the disc 133. In other words, the cutting disc 134 is movably positioned relative to the housing element 140, which includes the housing 131 and the opposing element 139, which moves integrally with the discs 132, 133, and 135, and the like. Furthermore, the annular sealing section 158 is provided on the outer circumferential side of the cutting disc 134, which is an unsupported side. The sealing section 158 seals between an outer circumference of the cutting disc 134 and an inner circumference of the housing 131 of the housing element 140.The sealing element 156, which includes the sealing section 158, is arranged centrally relative to the housing element 140 by contacting it. In other words, the inner circumferential side of the cutting disc 134 is supported by a simple support structure, which is supported by the disc 135 only on one surface side, without being clamped from both surfaces. The sealing section 158 is located on the side of the projecting section 143 of the cutting disc 134 in the axial direction and overlaps this projecting section 143 in the axial direction.

[0056] The opposing element 139 is provided on a side of the separating disc 134 opposite the bottom section 141. The opposing element 139 has a perforated, circular plate-like shape with a constant thickness, into which the mounting shaft section 28 of the piston rod 21 can be inserted, and is inserted into the cylindrical section 166 of the housing 131. The elastic section 159 is provided on a side of the separating disc 134 that faces the surface on which the sealing section 158 is provided. Therefore, the elastic section 159 is located between the side of the separating disc 134 opposite the surface on which the sealing section 158 is provided and the opposing element 139. A through-hole 167 is formed through the opposing element 139.The through-hole 167 penetrates a radial intermediate section of the opposing element 139 in an axial direction. The through-hole 167 is formed on a radially outer side of the opposing element 139 with respect to the disk 135 and is formed on a radially inner side with respect to the sealing element 156, which is brought into contact with the opposing element 139 due to a deflection of the disk 155.

[0057] The sealing section 158 of the separating disc 134 seals a space between the separating disc 134 and the cylindrical section 166 by contacting an inner circumferential surface of the cylindrical section 166 of the housing 131 over its entire circumference. In other words, the separating disc 134 is a sealing valve. The sealing section 158 continuously seals the space between the separating disc 134 and the cylindrical section 166, even if the separating disc 134 is deformed within a permissible range in the housing element 140. Because its sealing section 158 is in contact with the cylindrical section 166 over its entire circumference, the separating disc 134 is positioned centrally relative to the housing element 140, as described above.The separating disc 134 divides the interior of the housing element 140 into the variable chamber 171 (an internal housing chamber), which is located on one side of the bottom section 141 in the housing 131 and has a variable volume, and a variable chamber 172, which is located on one side of the opposite element 139 in the housing 131 and also has a variable volume. In other words, the separating disc 134 forms the variable chamber 171 between the separating disc 134 and the bottom section 141 of the housing 131. The variable chamber 171 is connected via a passage in the recess 151 of the disc 132 to a passage in the large-diameter hole section 146 of the housing 131, and the variable chamber 172 is connected via a passage in the through-bore 167 of the opposite element 139 to the lower chamber 20.

[0058] The piston rod 21 penetrates the annular element 117, the disc 116, the disc 115, the plurality of discs 114, the plurality of discs 113, the disc 112, the disc 111, the piston 18, the disc 51, the main valve 52, the disc 53, the disc 54, the seat element 55, the disc 56, the disc 57, the disc 58, the disc 59, the disc 60, the disc 61, the disc 62, the housing 131, the disc 132, and the disc 133, which are stacked in this order on the shaft step section 29, with the mounting shaft section 28 inserted therein in each case. The seat element 55 causes the sealing element 86 of the main valve 52 to be attached to the outer cylindrical section 73.

[0059] Furthermore, the cutting disc 134, with the disc 133 inserted therein, is placed on the projecting section 143 of the housing 131. The majority of discs 135 and the opposing element 139, each with its respective mounting shaft section 28 inserted therein, are stacked on the disc 133 in this order. The opposing element 139 is attached to the cylindrical section 166 of the housing 131. In addition, an annular element 175, which is a standard component made of the same material and having the same shape as the annular element 117, is placed on the opposing element 139 with its mounting shaft section 28 inserted therein.

[0060] A nut 176 engages thread-wise with the threaded bolt 31 of the fastening shaft section 28, which protrudes beyond the annular element 175 with the parts arranged in this manner. In this state, the stem section 29 of the piston rod 21 and the nut 176 sandwich between them the inner circumferential side or the entirety of each of the annular element 117, the disc 116, the disc 115, the plurality of discs 114, the plurality of discs 113, the discs 112 and 111, the piston 18, the disc 51, the main valve 52, the discs 53 and 54, the seat element 55, the discs 56 to 62, the housing 131, the discs 132 and 133, the plurality of discs 135, the opposing element 139, and the annular element 175, thereby clamping them axially. The inner circumferential side of the separating disc 134 is not axially clamped. The nut 176 is a universally applicable hexagonal nut.In the present embodiment, the nut 176 is indeed the universally applicable hexagonal nut, but it can have a surface other than six sides and / or can be designed using a special nut. Furthermore, the housing 131 and the annular element 175 can be fixed to the piston rod 21 by upsetting instead of being fastened using the nut 176.

[0061] In other words, the compression-side damping force generation mechanism 42, the piston 18, the expansion-side damping force generation mechanism 41, and the expansion-side damping force adjustment mechanism 43 are attached to the piston rod 21 using the nut 176, with the piston rod 21 being inserted at their respective inner circumferential sides. This means that the piston 18 and the housing 131, which forms the damping force adjustment mechanism 43, the disks 132 and 133, the plurality of disks 135, and the opposing element 139 are attached to the piston rod 21 using the nut 176, with the piston rod 21 being inserted at their respective inner circumferential sides. The piston rod 21 serves as a pin element that is inserted into the inner circumferential sides of the housing 131 and the opposite element 139 to fix the inner circumferential sides of the housing 131 and the opposite element 139.The housing element 140, which includes the housing 131 and the opposing element 139, the disks 132 and 133, the majority of disks 135 are provided on the piston 18.

[0062] The present embodiment provides a connection between the passage in the through-bore 87 of the disk 51, the passage in the large-diameter hole section 302 of the piston 18, the passage in the through-groove 30 of the piston rod 21, the passage in the large-diameter hole section 76 of the seat element 55 of the expansion-side damping force generation mechanism 41, and the passage in the large-diameter hole section 146 of the housing 131 of the damping force adjustment mechanism 43, wherein these are attached to the piston rod 21 in this manner.This results in a permanent connection between the pilot chamber 80 and the variable chamber 171 of the damping force adjustment mechanism 43 via the passage in the recess 91 of the disk 54, the passage in the large-diameter hole section 76 of the seat element 55, the passage in the through-groove 30 of the piston rod 21, the passage in the large-diameter hole section 146 of the housing 131, and the passage in the recess 151 of the disk 132. Furthermore, the present embodiment results in a permanent connection between the variable chamber 172 of the damping force adjustment mechanism 43 and the lower chamber 20 via the through-bore 167 of the opposite element 139.The passage in the recess 91, the passage in the large-diameter hole section 76, the passage in the through-groove 30, the passage in the large-diameter hole section 146, the passage in the recess 151 of the disk 132, the variable chambers 171 and 172, and the passage in the through-bore 167 branch off from the expansion-side first passage 101 described above and form an expansion-side second passage 181, which is provided parallel to the first passage 101 after the branching. Therefore, the two variable chambers 171 and 172, which are at least part of the second passage 181, are provided such that they are defined by the separating disk 134 inside the housing element 140.

[0063] The cutting disc 134 is designed to be deformable within a range in which its inner circumferential side moves between the disc 132 and the disc 135, and its outer circumferential side moves between the projecting section 143 and the opposing element 139. The shortest axial distance between the projecting section 143, which supports the outer circumferential side of the disc 155 of the cutting disc 134 from one axial side, and the disc 135, which supports the inner circumferential side of the disc 155 from the other axial side, is shorter than the axial thickness of the disc 155. Therefore, when the pressures in the variable chambers 171 and 172 are equal, the disc 155 is in a slightly deformed state over its entire circumference, due to a spring force acting on the disc 155, and is in contact with the projecting section 143 and the disc 135.The separating disc 134, with its inner circumferential surface in contact with the disc 135 over its entire circumference, blocks the flow of oil fluid between the variable chambers 171 and 172 of the second passage 181. The separating disc 134 is designed such that, regardless of the pressure conditions of the variable chambers 171 and 172, it remains in constant contact with the disc 135 over its entire circumference and therefore continuously blocks the flow between the variable chambers 171 and 172 of the second passage 181. The separating disc 134 can be configured as a check valve that blocks the flow during the expansion stroke but allows the flow during the compression stroke.

[0064] As in Fig. As illustrated in Figure 1, the bottom valve 25 described above is provided between the bottom element 12 of the outer tube 4 and the inner tube 3. This bottom valve 25 comprises a bottom valve element 191, a plurality of discs 192, a single disc 193, and a pin element 194. The bottom valve element 191 separates the lower chamber 20 and the reservoir chamber 6 from each other. The plurality of discs 192 are provided on a lower side, i.e., a side of the reservoir chamber 6, of this bottom valve element 191. The disc 193 is provided on an upper side, i.e., a side of the lower chamber 20, of the bottom valve element 191. The pin element 194 fastens the plurality of discs 192 and the disc 193 to the bottom valve element 191.

[0065] The bottom valve element 191 has an annular shape, with the pin element 194 inserted through its radial center. A plurality of through-holes 195 and a plurality of through-holes 196 are formed through the bottom valve element 191. The through-holes 195 allow the oil fluid to flow between the lower chamber 20 and the reservoir chamber 6. The through-holes 196 allow the oil fluid to flow between the lower chamber 20 and the reservoir chamber 6 on a radially outer side of these through-holes 195. The plurality of disks 192 on the reservoir chamber 6 side prevents or reduces the flow of oil fluid from the reservoir chamber 6 toward the lower chamber 20 through the through-holes 195, while allowing the flow of oil fluid from the lower chamber 20 toward the reservoir chamber 6 through the through-holes 195.The disk 193 prevents or reduces the flow of oil fluid from the lower chamber 20 towards the reservoir chamber 6 via the through holes 196, while allowing the flow of oil fluid from the reservoir chamber 6 towards the lower chamber 20 via the through holes 196.

[0066] The majority of discs 192, together with the bottom valve element 191, form a compression-side damping force generation mechanism 197. The compression-side damping force generation mechanism 197 causes the oil fluid to flow from the lower chamber 20 towards the reservoir chamber 6 and generates a damping force by opening during the compression stroke of the shock absorber 1. The disc 193, together with the bottom valve element 191, forms a suction valve 198. The suction valve 198 causes the oil fluid to flow from the reservoir chamber 6 towards the lower chamber 20 by opening during the expansion stroke of the shock absorber 1. The suction valve 198 fulfills the function of allowing the fluid to flow from the reservoir chamber 6 towards the lower chamber 20, essentially without generating damping force, thus compensating for a lack of fluid caused mainly by the extension and protrusion of the piston rod 21 from the cylinder 2.

[0067] If only the expansion-side damping force generation mechanism 41 is in operation during the expansion stroke, in which the piston rod 21 moves towards the expansion side while the piston 18's movement speed (hereinafter referred to as a piston speed) is slow, then the oil fluid flows from the upper chamber 19 through the passages in the through holes 38, the passage in the through bore 87 of the disk 51, the passage in the large-diameter hole section 302 of the piston 18, the passage in the through groove 30 of the piston rod 21, the passage in the large-diameter hole section 76 of the seat element 55 of the expansion-side damping force generation mechanism 41, the passage in the recess 91 of the disk 54, the pilot chamber 80, and the fixed opening 100 of the disk valve 99, which Fig. The first pass, illustrated in 3, 101, flows into the lower chamber 20, thereby generating a damping force according to a muzzle characteristic (the damping force is approximately proportional to the square of the piston speed). Therefore, the damping force has such a characteristic with respect to the piston speed that the damping force increases at a relatively high rate with respect to an increase in piston speed, as in a low-speed range on the left side of a solid line X11 in Fig. 4 indicated. Furthermore, as the piston speed increases, the oil flows from the upper chamber 19 through the passages in the through holes 38, the passage in the through bore 87, the passage in the large-diameter hole section 302 of the piston 18, the passage in the through groove 30 of the piston rod 21, the passage in the large-diameter hole section 76 of the seat element 55 of the expansion-side damping force generation mechanism 41, the passage in the recess 91 of the disk 54, and the pilot chamber 80, which form the first passage 101, into the lower chamber 20 by passing between the disk valve 99 and the valve seat section 79 while opening the disk valve 99, thereby generating a damping force according to a valve characteristic (the damping force is approximately proportional to the piston speed). At this point, the main valve 52 is closed.Therefore, the damping force has such a characteristic with respect to the piston speed that the damping force increases at a slightly lower rate with respect to the increase in piston speed, as starting from an intermediate speed range in the middle of the solid line X11 in a horizontal direction in . Fig. 4 up to a high-speed range.

[0068] In the present embodiment, the shock absorber 1 was described based on the example in which the main valve 52 is not opened even when the piston speed is in the high-speed range, in order to increase the damping force when the piston speed is in the intermediate to high-speed range. However, it can be configured to open the main valve 52 by adjusting the thickness of the main valve 52 plate, the pressure in the pilot chamber 80, and / or the like. In this case, there is a relationship between the forces (hydraulic pressures) applied to the main valve 52 such that a force applied by the passages in the through-holes 38 in an opening direction exceeds a force applied by the pilot chamber 80 in a closing direction.This relationship means that, according to the increase in piston speed, the main valve 52 is separated and opened from the valve seat section 47 of the piston 18, thereby allowing the oil fluid to flow into the lower chamber 20 via the passage 88 between the piston 18 and the outer cylindrical section 73 of the seat element 55, which forms the first passage 101. This is in addition to the flow into the lower chamber 20 from the passages in the through holes 38, the passage in the bore 87, and the pilot chamber 80, which also form the first passage 101, between the disc valve 99 and the valve seat section 79. This prevents or slows the increase in damping force. With this arrangement, the damping force can have such a characteristic with respect to piston speed that the damping force in the high-speed range lies on the right side of the solid line X11. Fig. 4 increases at a lower rate. The piston speed is defined as low if, for example, the piston speed is approximately 0 to 0.1 m / s, and the intermediate piston speed range and the high piston speed range are defined as a speed range of approximately 0.1 to 0.6 m / s and a speed range above 0.6 m / s, respectively.

[0069] During the compression stroke, in which the piston rod 21 moves towards the compression side, the oil fluid flows from the lower chamber 20 through the passages in the through-holes 39 and the fixed opening 123 of the disc valve 122, which in the Fig. The compression-side first passage 102, as illustrated in Figure 2, forms the upper chamber 19, which leads to the generation of the damping force according to the muzzle characteristic (the damping force is approximately proportional to the square of the piston speed). Therefore, the damping force has such a characteristic with respect to the piston speed that the damping force increases at a relatively high rate with respect to the increase in piston force, as in a low-speed range on the left side of a solid line X12 in Fig. 4 indicated. Furthermore, as the piston speed increases, the oil fluid introduced from the lower chamber 20 into the passages in the through-holes 39, which form the compression-side first passage 102, flows into the upper chamber 19, essentially passing between the disc valve 122 and the valve seat section 49, while opening the disc valve 122 and thereby generating the damping force according to the valve characteristic (the damping force is approximately proportional to the piston speed). Therefore, the damping force has such a characteristic with respect to the piston speed that the damping force increases at a slightly lower rate with respect to the increase in piston speed, as in intermediate and high-speed ranges from a center to a right side of the solid line X12 in the horizontal direction. Fig. 4 indicated.

[0070] The shock absorber 1 operates in the manner described above when only the damping force generation mechanisms 41 and 42 are in operation, but in the first embodiment, the damping force adjustment mechanism 43 makes the damping force variable according to the piston frequency even when the piston speed is unchanged.

[0071] More precisely, during the expansion stroke, when the piston frequency is high, the pressure in the upper chamber 19 increases, causing the oil fluid from the upper chamber 19 to flow through the passages into the Fig. The oil is introduced into the variable chamber 171 of the damping force adjustment mechanism 43 via the three illustrated through-holes 38, the through-hole 87 of the disk 51, the through-hole 302 of the piston 18, the through-hole 30 of the piston rod 21, and a section of the second through-hole 181 on one side of the pilot chamber 80 relative to the variable chamber 171. Accordingly, the oil fluid from the variable chamber 172 of the damping force adjustment mechanism 43, which is part of the second through-hole 181 on the side of the lower chamber 20, is discharged into the lower chamber 20 via the through-hole 167 of the opposite element 139. Accordingly, the separating disc 134, which until then was in contact with the projecting section 143 and the disc 135, is deformed in such a way that it displaces the elastic section 159 in the direction of the opposite element 139.

[0072] The deformation of the separating disc 134 in this manner leads to the introduction of the oil fluid from the upper chamber 19 into the variable chamber 171, resulting in a reduction of the flow rate of the oil fluid passing through the first passage 101 from the upper chamber 19 into the lower chamber 20. Due to this reduction, the pressure in the pilot chamber 80 does not increase, and the main valve 52 opens, generating a soft expansion-side damping force, as shown by a broken line X13 in Fig. 4 indicated. The inner circumferential side of the separating disc 134 is separated from the disc 132 and is only supported on one surface side by the disc 135 and is therefore slightly deformed so that it approaches the disc 132, and is therefore slightly deformed such that the elastic section 159 on the outer circumferential side approaches the opposite element 139.

[0073] Conversely, during the expansion stroke, in which the piston frequency is low, the frequency of deformation of the separating disk 134 also decreases accordingly. Thus, at the beginning of the expansion stroke, the oil fluid flows from the upper chamber 19 into the variable chamber 171. However, the separating disk 134 then comes into contact with the opposite element 139 and stops, thereby preventing the oil fluid from flowing from the upper chamber 19 to the variable chamber 171. This results in a state such that the amount of oil fluid flowing from the upper chamber 19 to the lower chamber 20, by being introduced into the first passage 101 (which includes the passages in the through-holes 38) and flowing through the damping force generation mechanism 41, is not reduced. This generates a strong expansion-side damping force, as shown by the solid line X11 in [Figure 1]. Fig. 4 indicated.

[0074] During the compression stroke, the pressure in the lower chamber 20 increases, but the separating disk 134 of the damping force adjustment mechanism 43 prevents or reduces the expansion of the variable chamber 172 by bearing against the projecting section 143 of the housing 131. This results in a reduction or elimination of the amount of oil fluid that is introduced from the lower chamber 20 into the variable chamber 172 via the passage in the through-hole 167 of the opposite element 139. Consequently, the amount of oil fluid flowing from the lower chamber 20 to the upper chamber 19 by entering the passages in the through-holes 39 and passing through the damping force generation mechanism 42 is not reduced, thus generating a hard damping force, as shown by the solid line X12 in Figure 1. Fig. Figure 4 illustrates this. Furthermore, the inner circumferential side of the cutting disc 134 is separated from the disc 135 and therefore no differential pressure is generated, so that the cutting disc 134 is not deflected.

[0075] The device discussed in JP 2011-247371A described above is equipped with a rod acceleration reduction mechanism on the bottom valve to prevent or reduce the generation of abnormal noise. In cases where the mechanism for achieving a predetermined characteristic is provided in the shock absorber in this way, the axial length of the shock absorber undesirably increases. The same applies to an embodiment in which a chamber is formed to compensate for a volume, such as a frequency-dependent shock absorber and a vibration damping mechanism. In such cases, it is desirable to reduce the axial length.

[0076] The damping force adjustment mechanism 43 according to the first embodiment is designed such that the variable chamber 171 in the housing 131 is defined by the annular, elastically deformable separating disc 134, which is provided with the annular sealing section 158 that seals between the separating disc 134 and the housing 131. Therefore, the present embodiment can reduce the axial length and thus reduce the basic length as well as the overall size of the shock absorber 1.

[0077] Furthermore, the sealing section 158 of the cutting disc 134, which seals between the outer circumference of the cutting disc 134 and the inner circumference of the housing 131, is provided on the side of the projecting section 143, which projects from the bottom section 141 of the housing 131 towards the cutting disc 134 and restricts the movement of the cutting disc 134. Therefore, the present embodiment can further reduce the axial length and thus further reduce the basic length and the overall size of the shock absorber 1.

[0078] The damping force adjustment mechanism 43, which includes the housing 131, is integrally movable with the piston 18. Therefore, the present embodiment can reduce the axial length of an integrally mounted assembly that includes the piston 18 and the piston rod 21.

[0079] The elastic section 159 is provided between the side of the cutting disc 134 facing the surface on which the sealing section 158 is provided and the opposing element 139. Therefore, the present embodiment can prevent or reduce noise generated by the contact of the cutting disc 134 with the opposing element 139. Furthermore, the present embodiment can mitigate the deformation of the cutting disc 134 due to the elastic deformation of the elastic section 159 and thereby smooth out a frequency-variable characteristic.

[0080] Furthermore, the present embodiment can reduce the axial length of the damping force adjustment mechanism 43 and thereby allow the respective inner circumferential sides of the piston 18 and the housing 131 of the damping force adjustment mechanism 43 to be attached to the piston rod 21 using the universally applicable nut 176 with the inserted piston rod 21. Therefore, the present embodiment allows for simple attachment of the piston 18 and the damping force adjustment mechanism 43 to the piston rod 21 and thus significantly improves ease of assembly.

[0081] Furthermore, the inner circumferential side of the cutting disc 134 is supported only on one surface side, without being clamped from both surfaces, and can therefore be easily deformed and the volume of the variable chambers 171 and 172 can be easily changed. Therefore, the present embodiment can improve the response of the damping force adjustment mechanism 43.

[0082] Furthermore, the expansion-side damping force generation mechanism 41 is a pressure-control type mechanism with the main valve 52, which generates the damping force by suppressing or reducing the flow of oil fluid generated by the sliding movement of the piston 18, and the pilot chamber 80, which causes the pressure to be applied to the main valve 52 in the valve opening direction, and is configured to introduce part of the flow of oil fluid into the pilot chamber 80 and to control the opening of the main valve 52 based on the pressure in the pilot chamber 80, in order to be able to generate the damping force as shown by the solid line X11 and the dashed line X13 in Fig. As indicated in Figure 4, the damping force adjustment mechanism 43 can be varied from the low-speed range of the piston 18, in which the oil fluid flows in a small quantity from the upper chamber 19 to the lower chamber 20, to the high-speed range of the piston 18, in which the oil fluid flows in a large quantity from the upper chamber 19 to the lower chamber 20, even if the volume of the damping force adjustment mechanism 43 can only be varied within a narrow range. Therefore, the present embodiment can, for example, improve vibration into a smooth ride when the piston speed is high and the frequency is high.

[0083] Furthermore, the portion of the second passage 181 formed on the piston rod 21 is formed by the through groove 30, which is formed on the outer circumferential section of the mounting shaft section 28 of the piston rod 21. Therefore, the processing of the present embodiment is facilitated.

[0084] Furthermore, the shock absorber 1 is provided with the damping force adjustment mechanism 43, which operates during the expansion stroke, and is not provided with a damping force adjustment mechanism that operates during the compression stroke. Therefore, the present embodiment can, for example, improve the driving feel and simultaneously prevent or reduce cost increases when the road surface is suitable for varying the damping force depending on the piston frequency during the expansion stroke.Furthermore, the present invention is preferably usable for a vehicle whose road handling is difficult to control with a shock absorber having a damping force adjustment mechanism that makes the damping force variable depending on the piston frequency during the compression stroke, and is able to effectively control its road handling by means of the shock absorber with the damping force adjustment mechanism 43, which makes the damping force variable depending on the piston frequency during the expansion stroke. [Second embodiment]

[0085] Next, a second embodiment will be described, primarily with reference to Fig. 5, Fig. 6 to Fig. 7 described, with the main focus being on differences from the first embodiment. Parts corresponding to those of the first embodiment are identified by the same designations and the same reference numerals.

[0086] As in Fig. As illustrated in Figure 5, in the second embodiment a damping force adjustment mechanism 43A is provided on a bottom valve 25A, which differs partially from the bottom valve 25. The bottom valve 25A includes the bottom valve element 191, the plurality of disks 192 and the single disk 193, which are similar to those of the first embodiment, as well as a pin element 194A, which differs partially from the pin element 194. The plurality of disks 192 together with the bottom valve element 191 form the damping force generation mechanism 197, and the single disk 193 together with the bottom valve element 191 forms the suction valve 198.

[0087] The bottom valve 25A includes a spacer 211 and a limiting disc 212. The spacer 211 is arranged on a side of the plurality of discs 192 opposite the bottom valve element 191 and has an outer diameter that is smaller than the outer diameter of the discs 192. The limiting disc 212 is arranged on a side of the spacer 211 opposite the discs 192 and has an outer diameter that is larger than the outer diameter of the spacer 211 and slightly smaller than the outer diameter of the discs 192. Furthermore, the bottom valve 25A includes a spacer 214, a spring element 215, a limiting disc 216, and a spacer 217. The spacer 214 is arranged on a side of the disc 193 opposite the bottom valve element 191 and has an outer diameter that is smaller than the outer diameter of the disc 193.The spring element 215 is arranged on the side of the spacer 214 opposite the disk 193. The limiting disk 216 is arranged on the side of the spring element 215 opposite the spacer 214 and has an outer diameter that is larger than the outer diameter of the spacer 211 and slightly smaller than the outer diameter of the disk 193. The spacer 217 is arranged on the side of the limiting disk 126 opposite the spring element 215 and has an outer diameter that is smaller than the outer diameter of the limiting disk 216.

[0088] The disc 193, which forms the suction valve 198, closes the through-hole 196 by bearing against the bottom valve element 191 and opens the through-hole 196 by separating from the bottom valve element 191. The spring element 215 comprises a plurality of spring sections 218 that extend radially outward and are inclined such that they approach the disc 193 more closely on its radially outer side. This plurality of spring sections 218 presses the disc 193 against the bottom valve element 191 with a slight preload force. A through-bore 221 is formed by the suction valve 198. The through-bore 221 establishes a permanent connection between the through-holes 195 of the bottom valve element 191 and the lower chamber 20.

[0089] The majority of discs 192, which form the damping force generation mechanism 197, close the through holes 195 by coming into contact with the bottom valve element 191, and open the through holes 195 by separating from the bottom valve element 191.

[0090] The pin element 194A comprises a mounting shaft section 225 and a flange section 226. The flange section 226 extends radially outward from an axial side of the mounting shaft section 225. A threaded stud 227 is formed on an outer circumferential section of the mounting shaft section 225 on a side axially opposite the flange section 226. A through-hole 231 and a through-hole 232 are formed at the radial center of the mounting shaft section 225. The through-hole 231 extends axially from an end section on one side of the flange section 226 to a position on the way to the side of the other end. The through-hole 232 penetrates the mounting shaft section 225 radially, intersecting the through-hole 231.

[0091] The damping force adjustment mechanism 43A comprises a single cylindrical housing with a base 131A, a single passage-forming element 241, a single disc 242, a plurality of discs 243, and a single separating disc 134A (one disc), as well as an opposing element 139A opposite the separating disc 134A, in that order starting from one side of the base valve 25A in the axial direction. The housing 131A, the passage-forming element 241, the discs 242 and 243, and the opposing element 139A are made of metal. Both discs 242 and 243 have a perforated, circular plate-like shape with a constant thickness, into which the mounting shaft section 225 of the pin element 194A can be inserted. The through-forming element 241, the housing 131A and the opposing element 139A all have a ring-shaped form into which the fastening shaft section 225 of the pin element 194A can be inserted.

[0092] The opposing element 139A comprises a perforated, disc-like base section 251 and an annular projecting section 252. The projecting section 252 extends from an outer circumferential section of the base section 251 in the direction of an axial side. A plurality of recesses 253 are formed partially circumferentially on the projecting section 252, and these recesses 253 penetrate the projecting section 252 in a radial direction.

[0093] The housing 131A comprises a perforated disc-shaped base section 141A and a cylindrical tubular section 166A. The base section 141A extends along the direction orthogonal to the axis. The tubular section 166A extends axially from an outer circumferential edge section of the base section 141A.

[0094] The through-flow element 241 is positioned on the base section 141A of the housing 131A. A plurality of radially extending grooves 246 are formed on the through-flow element 241 on one side of the base section 141A. The disk 242 has an outer diameter that is smaller than the outer diameter of the through-flow element 241. The plurality of disks 243 have outer diameters that are smaller than the outer diameter of the disk 242.

[0095] The separating disc 134A comprises a metallic disc 155A and a rubber sealing element 156A, which is fixedly attached to an outer circumferential side of the disc 155A and is elastically deformable. The disc 155A has a perforated, circular plate-like shape with a constant thickness, which can be spaced apart from the plurality of discs 243 arranged inside the disc 155A and has a thickness that is thinner than the sum of the thicknesses of the plurality of discs 243. The disc 155A has an outer diameter that is larger than the outer diameter of the projecting section 252 of the opposing element 139A and smaller than the inner diameter of the tubular section 166A of the housing 131A.

[0096] The projecting section 252 of the opposing element 139A extends towards the disc 155A of the cutting disc 134A and restricts any movement of the disc 155A beyond that in the direction of one side of the opposing element 139A by bearing against the disc 155A. The projecting section 252 supports an outer circumferential side of the cutting disc 134A by means of its end section on a projecting distal side. Furthermore, a radially inner side and a radially outer side of the projecting section 252 are in constant communication with each other via the recesses 253.

[0097] The sealing element 156A is fixedly attached in an annular form to an outer circumferential side of the disc 155A. The sealing element 156A comprises an annular sealing section 158A and an annular elastic section 159A. The sealing section 158A projects axially from the disc 155A toward one side of the opposing element 139A. The elastic section 159A projects axially from the disc 155A toward a side opposite the opposing element 139A. The sealing section 158A has its smallest inner diameter at one end section on one side of the disc 155A, and this inner diameter is larger than the outer diameter of the projecting section 252. Due to this design, the separating disc 134A allows its disc 155A to abut the projecting section 252 of the opposing element 139A.A radial groove 161A is formed by the elastic section 159A. The radial groove 161A is open on one side opposite the disk 155A and extends in a radial direction.

[0098] The disc 242 has an outer diameter that is larger than the inner diameter of the disc 155A of the cutting disc 134A. Due to this design, an inner circumferential side of the cutting disc 134A is movably supported over an axial length corresponding to the majority of discs 243 between the disc 242 and the opposing element 139A. In other words, the cutting disc 134A is movably positioned relative to the housing 131A and the opposing element 139A, which move integrally with the passage-forming element 241 and the discs 242 and 243. Furthermore, the annular sealing section 158A is provided on the outer circumferential side of the cutting disc 134A, which is an unsupported side. The sealing section 158A seals between an outer circumference of the cutting disc 134A and an inner circumference of the housing 131A.The sealing element 156A, which includes the sealing section 158A, is positioned centrally relative to the housing 131A by contacting it. In other words, the inner circumferential side of the cutting disc 134A has a simple support structure that is supported by the disc 242 on only one surface side, without being clamped from both surface sides. The sealing section 158A is provided on one side of the projecting section 252 of the cutting disc 134A in the axial direction and overlaps this projecting section 252 axially.

[0099] The opposing element 139A is positioned such that it faces the separating disc 134A on a side of the separating disc 134A opposite the bottom section 141A. The opposing element 139A has a perforated, circular plate-like shape into which the mounting shaft section 225 of the pin element 194A can be inserted. The elastic section 159A is located on the surface of the separating disc 134A opposite the surface on which the sealing section 158A is located, and is thus situated between the surface of the separating disc 134A opposite the surface on which the sealing section 158A is located and the bottom section 141A of the housing 131A.

[0100] The sealing section 158A of the cutting disc 134A is in contact with an inner circumferential surface of the tubular section 166A of the housing 131A over its entire circumference, thereby sealing a space between the cutting disc 134A and the tubular section 166A. The sealing section 158A continuously seals the space between the cutting disc 134A and the tubular section 166A, even if the cutting disc 134A is deformed relative to the housing 131A within a permissible range. Due to the contact of its sealing section 158A with the tubular section 166A over its entire circumference, the cutting disc 134A is positioned centrally relative to the housing 131A, as described above. The separating disc 134A, together with the housing 131A on one side of the bottom section 141A, defines a variable chamber 171A (a housing inner chamber) with a variable volume within the housing 131A.One surface of the separating disc 134A, opposite the variable chamber 171A, lies opposite the lower chamber 20. The separating disc 134A forms the variable chamber 171A between the housing 131A and the bottom section 141A. The variable chamber 171A is in constant communication with the reservoir chamber 6 via passages in the radial grooves 246 of the passage-forming element 241, a passage in the through-hole 232 of the pin element 194A, and a passage in the through-hole 231.

[0101] The pin element 194A penetrates the limiting disc 212, the spacer 211, the plurality of discs 192, the bottom valve element 191, the disc 193, the spacer 214, the spring element 215, the limiting disc 216, the spacer 217, the housing 131A, the passage-forming element 241, the disc 242, the plurality of discs 243, and the opposing element 139A, which are mounted on the flange section 226 in this order with the mounting shaft section 225 inserted therein. The separating disc 134A is inserted into the housing 131A and arranged between the disc 242 and the opposing element 139A. In this state, the through hole 232 of the pin element 194A is connected to the majority of radial grooves 246 of the through-forming element 241.

[0102] A nut 176A engages thread-wise with the threaded bolt 227 of the fastening shaft section 225, which, with the parts arranged in this way, protrudes beyond the opposite element 139A of the pin element 194A. In this state, the flange section 226 of the pin element 194A and the nut 176A sandwich between them the inner circumferential side or the entirety of the limiting washer 212, the spacer 211, the plurality of washers 192, the bottom valve element 191, the washer 193, the spacer 214, the spring element 215, the limiting washer 216, the spacer 217, the housing 131A, the passage-forming element 241, the washer 242, the plurality of washers 243, and the opposing element 139A, thereby clamping them axially. The inner circumferential side of the separating washer 134A is not axially clamped. The nut 176A is a universally applicable hexagonal nut.The pin element 194A is inserted into and secures the inner circumferential sides of the housing 131A and the opposing element 139A. In the present embodiment, the nut 176A is a universally applicable hexagonal nut, but it may have a surface other than six sides and / or may be designed using a special nut. Furthermore, the fastening shaft section 225, which projects beyond the opposing element 139A of the pin element 194A, may be secured by upsetting instead of being fastened using the nut 176.

[0103] In the second embodiment, the damping force adjustment mechanism 43A, which is formed by the housing 131A, the passage forming element 241, the discs 242 and 243, the opposing element 139A and the separating disc 134A, is provided on the bottom valve 25A in the manner described above.

[0104] The cutting disc 134A is designed to be movable within a range in which its inner circumferential side moves between the disc 242 and the base section 251 of the opposing element 139A, and its outer circumferential side moves between the projecting section 252 and the bottom section 141A of the housing 131A. The shortest axial distance between the projecting section 252, which supports the outer circumferential side of the disc 155A of the cutting disc 134A from one axial side, and the disc 242, which supports the inner circumferential side of the disc 155A from the other axial side, is shorter than one axial thickness of the disc 155A. Therefore, if the pressures in the variable chamber 171A and the lower chamber 20 are equal, then the disk 155A is in a slightly deformed state over its entire circumference due to a spring force of the disk 155A, in contact with the projecting section 252 and the disk 242.The separating disc 134A, with its inner circumferential side which is in contact with the disc 242 over its entire circumference, blocks the flow of oil fluid between the variable chamber 171A and the lower chamber 20. Furthermore, the separating disc 134A, with its inner circumferential side separated from the disc 242, allows the flow of oil fluid between the variable chamber 171A and the lower chamber 20.

[0105] Therefore, the inner circumferential surface of the separating disc 134A and the disc 242 form a check valve 255, which restricts the flow of oil fluid from the lower chamber 20 to the variable chamber 171A, while allowing the flow of oil fluid from the variable chamber 171A to the lower chamber 20. The check valve 255 is a free valve in which the entire separating disc 134A, which serves as its valve body, is axially movable.

[0106] When the pressure in the lower chamber 20 falls below the pressure in the reservoir chamber 6 (atmospheric pressure) during the expansion stroke, this pressure is applied to the separating disk 134A. The inner circumferential side of disk 155A of separating disk 134A then separates from disk 242, and the check valve 255 opens. As a result, the oil fluid in the reservoir chamber 6 flows into the lower chamber 20 through a passage in the through-hole 231, a passage in the through-hole 232, passages in the radial grooves 246, the variable chamber 171A, a passage between disk 155A of the open check valve 255 and disk 242, a passage between the base section 251 of the opposite element 139A and disk 155A, and a passage in the recess 253 (see dashed arrows in the figure). Fig. 6(a)).

[0107] There, as in Fig. Figure 5 illustrates that the variable chamber 171A and the reservoir chamber 6 are connected to each other via the passages in the radial grooves 246, the passage in the through-hole 232, and the passage in the through-hole 231. When, during the compression stroke at a high frequency, such as during vibration, the pressure in the lower chamber 20 exceeds the pressure in the reservoir chamber 6, the separating disc 134A is deformed towards the side of the bottom section 141A to reduce the volume of the variable chamber 171A and simultaneously cause the oil fluid in the variable chamber 171A to flow into the reservoir chamber 6 (see dashed arrows in Figure 5). Fig. 6(b)). Then, accordingly, the volume of the lower chamber 20 increases. As a result, compared to the first embodiment, indicated by a solid line X12, a soft damping force is generated, as shown in Fig. 7 indicated by a broken line X21.

[0108] According to the second embodiment, the damping force adjustment mechanism 43A, which includes the housing 131A, is provided as a single piece on the bottom valve 25A.

[0109] Therefore, the second embodiment allows a shorter axial length of the shock absorber 1 compared to the design disclosed in the document of the conventional prior art.

[0110] The elastic section 159A is located between the side of the cutting disc 134A opposite the surface on which the sealing section 158A is provided and the bottom section 141A of the housing 131A. Therefore, the second embodiment can prevent or reduce noise generated by contact between the cutting disc 134A and the bottom section 141A of the housing 131A. Furthermore, the elastic section 159A is elastically deformable, so that the second embodiment mitigates the deformation of the cutting disc 134A and thus smooths out the frequency-variable characteristic. [Third embodiment]

[0111] Next, a third embodiment will be described, primarily with reference to Fig. 8 described, with the main focus being on differences from the second embodiment. Parts corresponding to those of the second embodiment are identified by the same designations and the same reference numerals.

[0112] In the third embodiment, the shock absorber 1 includes a bottom valve 25B, which differs from the bottom valve 25 in that it includes a pin element 194B that is partially different from the pin element 194A. The damping force adjustment mechanism 43A is attached to the bottom valve 25B in a position reversed compared to the second embodiment. The pin element 194B includes a through-hole 231B formed by the mounting shaft section 225. The through-hole 231B has a greater depth than the through-hole 231. Furthermore, a through-hole 232B is formed at a position that is further away from the flange section 226 than the through-hole 232 and intersects the through-hole 231B.

[0113] The pin element 194B penetrates the limiting disc 212, the spacer 211, the plurality of discs 192, the bottom valve element 191, the disc 193, the spacer 214, the spring element 215, the limiting disc 216, the spacer 217, the opposing element 139A, the plurality of discs 243, the disc 242, the passage-forming element 241, the housing 131A, and a washer 261, which are stacked in this order on the flange section 226 with the mounting shaft section 225 inserted therein. The separating disc 134A is inserted into the housing 131A and arranged between the disc 242 and the opposing element 139A. In this state, the through-hole 232B is connected to the majority of radial grooves 246 of the through-forming element 241.

[0114] The nut 176A engages thread-wise with the threaded bolt 227 of the fastening shaft section 225, which, with the parts arranged in this way, protrudes beyond the washer 261 of the pin element 139A. In this state, the flange section 226 of the pin element 194B and the nut 176A sandwich between them the inner circumferential side or the entirety of the limiting washer 212, the spacer 211, the plurality of washers 192, the bottom valve element 191, the washer 193, the spacer 214, the spring element 215, the limiting washer 216, the spacer 217, the opposing element 139A, the plurality of washers 243, the washer 242, the passage-forming element 241, the housing 131A, and the diaphragm washer 261, thereby clamping them axially. The inner circumferential side of the separating washer 134A is not axially clamped.The pin element 194B is also inserted into the inner circumferential sides of the housing 131A and the opposing element 139A and secures the inner circumferential sides of the housing 131A and the opposing element 139A, analogous to the second embodiment. The passage in the through-hole 231B, the passage in the through-hole 232B, and the passages in the radial grooves 246 establish a permanent connection between the reservoir chamber 6 and the variable chamber 171A.

[0115] The third embodiment also functions in a similar way to the second embodiment. [Fourth embodiment]

[0116] Next, a fourth embodiment will be described, primarily with reference to Fig.9 is described, with the main focus being on differences from the second embodiment. Parts corresponding to those of the second embodiment are identified by the same designations and the same reference numerals.

[0117] In the fourth embodiment, the shock absorber 1 includes a bottom valve 25C, which differs from the bottom valve 25A in that it includes a pin element 194C that is partially different from the pin element 194A. The pin element 194C includes a mounting shaft section 225C that is axially longer than the pin element 194A.

[0118] Furthermore, in the fourth embodiment, the shock absorber 1 includes a damping force adjustment mechanism 43C, which differs partially from the damping force adjustment mechanism 43A. The damping force adjustment mechanism 43C includes a housing 131C, which contains a cylindrical tubular section 166C. The cylindrical tubular section 166C extends axially with a greater length from an outer circumferential edge section of the bottom section 141A, which is similar to that of the second embodiment, than the tubular section 166A. The damping force adjustment mechanism 43C also includes the passage-forming element 241, the disc 242, the plurality of discs 243, and the separating disc 134A, each similar to those of the second embodiment, and includes an opposing element 139C, which differs partially from the opposing element 139A.

[0119] The opposing element 139C comprises a perforated, disc-shaped base section 251C, an annular projecting section 252 similar to that of the second embodiment, and an annular projecting section 252C. The projecting section 252 projects from an outer circumferential section of the base section 251C in the direction of one axial side. The projecting section 252C projects from the outer circumferential section of the base section 251C in the direction of the other axial side. The plurality of recesses 253, which resemble those of the second embodiment, are formed on the projecting section 252. A plurality of recesses 253C are also formed partially circumferentially on the projecting section 252C. These recesses 253C penetrate the projecting section 252C in the radial direction.A plurality of axially extending through-holes 271 are formed by the base section 251C on a radially inner side relative to the projecting sections 252 and 252C. A projection section 272 is provided on a radially inner side of the base section 251C relative to the through-holes 271. The projection section 272 extends from the base section 251C in the same direction as the projecting section 252C.

[0120] The damping force adjustment mechanism 43C comprises a plurality of discs 242C, a cover element 275, and a cutting disc 134C similar to the cutting disc 134A. The cover element 275 includes a perforated, disc-like base section 276 and an annular extension section 277. The extension section 277 projects from an inner circumferential section of the base section 276 toward an axial side. A plurality of axially extending through-holes 278 are formed through the base section 276. The cover element 275 is integrated with the housing 131C by being attached to the tubular section 166C, with the extension section 277 projecting beyond the base section 276 toward the side of the bottom section 141A.

[0121] The projecting section 252 of the opposite element 139C projects towards the disk 155A of the cutting disk 134A and restricts a movement of the disk 155A that goes beyond that in the direction of one side of the opposite element 139C by bearing against the disk 155A.

[0122] The projecting section 252C of the opposing element 139C extends towards the disc 155A of the cutting disc 134C and restricts any movement of the disc 155A beyond that towards the side of the opposing element 139C by bearing against the disc 155A. The projecting section 252C supports an outer circumferential side of the cutting disc 134C by means of an end section of its projecting distal side. Furthermore, a radially inner side and a radially outer side of the projecting section 252C are in constant communication with each other via the recesses 253C.

[0123] The sealing section 158A of the sealing element 156A of the cutting disc 134C has its smallest inner diameter at its end section on one side of the disc 155A, and this inner diameter is slightly larger than the outer diameter of the projecting section 252C. Due to this design, the cutting disc 134C allows its disc 155A to abut the projecting section 252C of the opposite element 139C.

[0124] The disc 242C has an outer diameter that is larger than the inner diameter of the disc 155A of the cutting disc 134C. Due to this design, an inner circumferential side of the cutting disc 134C is movably supported in a region spanning the axial length of the extension section 272 between the disc 242C and the base section 251C of the opposing element 139C. In other words, the cutting disc 134C is movably positioned relative to the housing 131C and the cover element 275, which move integrally with the passage element 241, the discs 242C and 243, and the opposing element 139C. Furthermore, the annular sealing section 158A is provided on an outer circumferential side of the cutting disc 134C, which is an unsupported side. The sealing section 158A seals between an outer circumference of the cutting disc 134C and the inner circumference of the housing 131C.The sealing element 156A, which includes the sealing section 158A, is positioned centrally relative to the housing 131C by contacting it. In other words, the inner circumferential side of the cutting disc 134C has a simple support structure that is supported by the disc 242C on only one surface side, without being clamped from both surface sides. The sealing section 158A of the cutting disc 134C is located on one side of the projecting section 252C of the cutting disc 134C in the axial direction and overlaps this projecting section 252C axially.

[0125] The sealing section 158A of the separating disc 134A is in contact with the inner circumferential surface of the tubular section 166C of the housing 131C over its entire circumference, thereby sealing the space between the separating disc 134A and the tubular section 166C. The sealing section 158A of the separating disc 134C is also in contact with the inner circumferential surface of the tubular section 166C of the housing 131C over its entire circumference, thereby sealing a space between the separating disc 134C and the tubular section 166C. Together with the housing 131C, the separating disc 134A defines a variable chamber 171C (an inner chamber of the housing) with a variable volume on one side of the bottom section 141A within the housing 131C.The variable chamber 171C is in constant communication with the reservoir chamber 6 via the passages in the radial grooves 246 of the passage forming element 241, the passage in the through hole 232 of the pin element 194C and the passage in the through hole 231.

[0126] The cutting discs 134A and 134C, together with the housing 131C, define a variable chamber 281 with a variable volume between them. The cutting disc 134C and the cover element 275, together with the housing 131C, define a variable chamber 282 with a variable volume between them. This variable chamber 282 is in constant communication with the lower chamber 20 via the through-holes 278.

[0127] The pin element 194C penetrates the limiting washer 212, the spacer 211, the plurality of washers 192, the bottom valve element 191, the washer 193, the spacer 214, the spring element 215, the limiting washer 216, the spacer 217, the housing 131C, the passage forming element 241, the washer 242, the plurality of washers 243, the opposing element 139C, the plurality of washers 242C and the cover element 275, which are stacked in this order on the flange section 226, with the fastening shaft section 225C inserted therein in each case. The cutting disc 134A is inserted into the housing 131C and arranged between the disc 242 and the opposite element 139C, and the cutting disc 134C is inserted into the housing 131C and arranged between the opposite element 139C and the disc 242C.In this state, the through-hole 232 is in contact with the majority of radial grooves 246 of the through-forming element 241. The cover element 275 is attached to the tubular section 166C of the housing 131C.

[0128] The nut 176A engages thread-wise with the threaded bolt 227 of the fastening shaft section 225C, which, with the parts arranged in this way, protrudes beyond the cover element 275 of the pin element 194C. In this state, the flange section 226 of the pin element 194C and the nut 176A sandwich between them the inner circumferential side or the entirety of each of the limiting washer 212, the spacer 211, the plurality of washers 192, the bottom valve element 191, the washer 193, the spacer 214, the spring element 215, the limiting washer 216, the spacer 217, the housing 131C, the passage-forming element 241, the washer 242, the plurality of washers 243, the opposing element 139C, the plurality of washers 242C, and the cover element 275, thereby clamping them axially. The inner circumferential sides of the separating washers 134A and 134C are not axially clamped.The pin element 194C is inserted into the inner circumferential sides of the housing 131C and the opposite element 139C and secures the inner circumferential sides of the housing 131C and the opposite element 139C.

[0129] In the fourth embodiment, the damping force adjustment mechanism 43C, which is formed by the housing 131C, the opposing element 139C, the cover element 275, the passage forming element 241, the discs 242, 242C and 243, the opposing element 139C and the separating discs 134A and 134C, is provided on the bottom valve 25C in the manner described above.

[0130] The cutting disc 134A is designed to be deformable within the area in which its inner circumferential side moves between the disc 242 and the opposing element 139C, and its outer circumferential side moves between the projecting section 252 and the bottom section 141A of the housing 131C. The shortest axial distance between the projecting section 252, which supports the outer circumferential side of the disc 155A of the cutting disc 134A from one axial side, and the disc 242, which supports the inner circumferential side of the disc 155A of the cutting disc 134A from the other axial side, is shorter than the axial thickness of the disc 155A of the cutting disc 134A.Therefore, if the pressures in the variable chamber 171C and the variable chamber 281 are equal, then the disk 155A of the cutting disk 134A is in a slightly deformed state over its entire circumference due to the spring force of the disk 155A and is in pressure contact with the projecting section 252 and the disk 242.

[0131] The separating disc 134, with its inner circumferential surface in contact with disc 242 over its entire circumference, blocks the flow of oil fluid between variable chamber 171C and variable chamber 281. Furthermore, the separating disc 134A, with its inner circumferential surface separated from disc 242, allows the flow of oil fluid between variable chamber 171C and variable chamber 281. Therefore, the inner circumferential surface of separating disc 134A and disc 242 form the check valve 255, which restricts the flow of oil fluid from variable chamber 281 to variable chamber 171C, while allowing the flow of oil fluid from variable chamber 171C to variable chamber 281.

[0132] The cutting disc 134C is designed to be deformable within a range in which its inner circumferential side moves between the disc 242C and the base section 251C of the opposing element 139C, and its outer circumferential side moves between the projecting section 252C and the base section 276 of the cover element 275. The shortest axial distance between the projecting section 252C, which supports the outer circumferential side of the disc 155A of the cutting disc 134C from one axial side, and the disc 242C, which supports the inner circumferential side of the disc 155A of the cutting disc 134C from the other axial side, is shorter than the axial thickness of the disc 155A of the cutting disc 134C.Therefore, if the pressures in the variable chamber 281 and the variable chamber 282 are equal, then the disk 155A of the cutting disk 134C is in a slightly deformed state over its entire circumference due to a spring force of the disk 155A, in contact with the projecting section 252C and the disk 242C.

[0133] The separating disc 134C, with its inner circumferential surface in contact with the disc 242C over its entire circumference, blocks the flow of oil fluid between the variable chamber 281 and the variable chamber 282. Furthermore, the inner circumferential surface of the separating disc 134C, which is separate from the disc 242C, allows the flow of oil fluid between the variable chamber 281 and the variable chamber 282. Therefore, the inner circumferential surface of the separating disc 134C and the disc 242C form a check valve 255C, which restricts the flow of oil fluid from the variable chamber 281 through the variable chamber 282 to the lower chamber 20, while allowing the flow of oil fluid from the lower chamber 20 through the variable chamber 282 to the variable chamber 281.

[0134] When the pressure in the variable chamber 281 falls below the pressure in the variable chamber 171C, the inner circumferential side of the disc 155A of the separating disc 134A, which forms the check valve 255, is separated from the disc 242, and the oil fluid in the reservoir chamber 6 flows into the variable chamber 281 by passing through the passage in the through-hole 231, the passage in the through-hole 232, the passages in the radial groove 246, the variable chamber 171C, the passage between the disc 155A of the check valve 255 in the open state and the disc 242, the passage between the opposite element 139C and the disc 155A of the separating disc 134A, and the passages in the recesses 253.When the pressure in the lower chamber 20 decreases during the expansion stroke, the pressure in the variable chamber 282, which is connected to the lower chamber 20 via the through-holes 278 of the cover element 275, also decreases, and this pressure is applied to the separating disc 134C. The separating disc 134C is then deformed towards one side of the cover element 275, simultaneously causing the oil fluid in the reservoir chamber 6 to flow into the variable chamber 281 according to the flow pattern described above. This, in turn, causes the oil fluid in the variable chamber 282 to flow into the lower chamber 20. As a result, a soft damping force is generated.

[0135] During the compression stroke, the pressure in the lower chamber 20 increases, and the pressure in the variable chamber 282, which is connected to the lower chamber 20 via the through-holes 278 of the cover element 275, also increases. When the pressure in the variable chamber 282 exceeds the pressure in the variable chamber 281, the inner circumferential side of the disc 155A, which forms the check valve 255C, separates from the disc 242C, causing the oil fluid in the variable chamber 282 to flow into the variable chamber 281, resulting in an increase in the pressure in the variable chamber 281.Since the variable chamber 171C is connected to the reservoir chamber 6, the separating disc 134A is deformed towards the side of the bottom section 141A, while the oil fluid in the variable chamber 171C is caused to flow into the reservoir chamber 6 due to the pressure increase in the variable chamber 281, thereby increasing the volume of the variable chamber 282. As a result of this process, the volume of the variable chamber 171C decreases, and the volume of the variable chamber 281, which is connected to the side of the lower chamber 20, increases accordingly. Consequently, a soft damping force is generated.

[0136] In the first embodiment, the shock absorber 1 can be configured to support the outer circumferential side of the cutting disc 134 by means of the housing 131 integrated with the piston rod 21, and can include an annular sealing element that seals a space with the side of the piston rod 21 on the inner circumferential side of the cutting disc 134, which is the unsupported side. Similarly, in the second and / or third embodiment, the shock absorber 1 can be configured to support the outer circumferential side of the cutting disc 134A by means of the housing 131A integrated with the pin element 194A or 194B, and can include an annular sealing element that seals a space with the side of the pin element 194A or 194B on the inner circumferential side of the cutting disc 134A, which is the unsupported side.Similarly, in the fourth embodiment, the shock absorber 1 can be designed to support the outer circumferential side(s) of the cutting disc(s) 134A and / or 134C through the housing 131C integrated with the pin element 194C, and can include an annular sealing element that seals a space with the side of the pin element 194C on the inner circumferential side(s) of the cutting disc(s) 134A and / or 134C, which is the unsupported side.

[0137] The embodiments described above were based on the example in which the present invention is used for a twin-tube hydraulic shock absorber. However, the applicability of the present invention is not limited thereto, and the present invention is applicable to a single-tube hydraulic shock absorber in which the outer tube is omitted and a gas chamber is formed in the cylinder 2 by means of a sliding separating element on the side of the lower chamber 20 that is opposite the upper chamber 19, and is applicable to any type of shock absorber. Furthermore, the present invention is also applicable if an oil passage communicating with the interior of the cylinder 2 is provided outside the cylinder 2 and the damping force generation mechanism is provided in this oil passage.

[0138] The embodiments described above were based on the example in which the shock absorber is designed to include the elastic section between the side of the disc opposite the surface on which the sealing section is provided and the opposing element or the bottom section of the housing, and the elastic section is integrally formed with the disc. However, the present invention is not limited to this, and the elastic section can, for example, be attached to the opposing element. Alternatively, the elastic section can be omitted.

[0139] In the embodiments described above, the shock absorber includes the cylinder, which contains the hydraulic fluid in a densely packed manner; the piston, which is slidably and precisely inserted into the cylinder and defines the rod-side chamber and the bottom-side chamber in the cylinder; the piston rod, one end of which is fixed to the piston in the cylinder and the other end of which projects out of the cylinder via the rod guide; the damping force generation mechanism, which is designed to generate the damping force by the movement of the piston; the cylindrical housing with a bottom; the disk, which is movably arranged relative to the housing and forms the inner chamber of the housing between the bottom section of the housing and the disk; and the opposing element, which is arranged on the side of the disk opposite the bottom section, opposite the disk.The inner circumferential sides of the housing and the opposing element are fixed by the pin element passing through them. The projecting section is formed on the bottom section of the housing or the opposing element. The projecting section extends toward the disc and is designed to restrict the disc's movement. The sealing section is located on the side of the projecting section of the disc. The sealing section is designed to seal between the outer circumference of the disc and the inner circumference of the housing. The sealing section of the disc, which seals between the outer and inner circumferences of the disc, is located on the side of the projecting section that extends from the bottom section of the housing toward the disc and restricts the disc's movement. Therefore, this design allows for a shorter axial length and a smaller size of the shock absorber.

[0140] Furthermore, the housing is mounted on the piston. Therefore, this design of the shock absorber allows for a shorter overall axial length of those parts that move integrally with the piston and piston rod.

[0141] Furthermore, the cylinder includes the inner tube and the outer tube on the outer circumferential side of the inner tube. The bottom valve is located between the inner and outer tubes, and the housing is positioned on top of the bottom valve. Therefore, this design of the shock absorber allows for an even shorter overall axial length of those parts that move integrally with the piston and piston rod.

[0142] The elastic section is located between the side of the disc opposite the surface where the sealing section is provided and the opposing element or the bottom section of the housing. This design can therefore prevent or reduce noise generated by the disc contacting the opposing element or the bottom section of the housing. Furthermore, the pin element forms one end face of the piston rod. Additionally, the annular space is formed between the disc and the housing, and the sealing section is designed to be firmly attached to both surfaces of the disc across this space.

[0143] A first aspect of the shock absorber includes a cylinder containing a densely packed hydraulic fluid, a piston that is slidably and precisely inserted into the cylinder and defines a rod-side chamber and a bottom-side chamber in the cylinder, a piston rod whose one end face is fixed to the piston in the cylinder and whose other end face protrudes from the cylinder via a rod guide, a damping force generation mechanism designed to generate a damping force by movement of the piston, a cylindrical housing with a bottom, a disk that is movably arranged relative to the housing and forms an inner housing chamber between a bottom section of the housing and the disk, and an opposing element that is arranged on a side of the disk opposite the bottom section and opposite the disk.The inner perimeter sides of the housing and the opposing element are fixed by a pin element passing through them. A projecting section is formed on the bottom section of the housing or the opposing element. The projecting section extends toward the disk and is designed to restrict disk movement. A sealing section is provided on the side of the disk where the projecting section is located. The sealing section is designed to seal between an outer circumference of the disk and an inner circumference of the housing.

[0144] According to a second aspect of the shock absorber, the housing is provided on the piston in the first aspect.

[0145] According to a third aspect of the shock absorber, the cylinder in the first or second aspect includes an inner tube and an outer tube on an outer circumferential side of the inner tube. A bottom valve is provided between the inner tube and the outer tube, and the housing is provided on the bottom valve.

[0146] According to a fourth aspect of the shock absorber, in one of the first to third aspects, an elastic section is provided between a side of the disc that faces a surface of the disc on which the sealing section is provided and the opposite element or the bottom section of the housing.

[0147] According to a fifth aspect of the shock absorber, the pin element in the first aspect is one end face of the piston rod.

[0148] According to a sixth aspect of the shock absorber, in the first to fifth aspects an annular space is formed between the disc and the housing, and the sealing section is provided in such a way that it is firmly attached to the two surfaces of the disc over the space. REFERENCE MARK LIST 1 shock absorber 2 cylinders 3 inner tube 4 outer pipe 18 pistons 19 upper chamber (rod-side chamber) 20 lower chamber (bottom chamber) 21 Piston rod (pin element) 25A, 25B, 25C Bottom valve 41, 42, 197 Damping force generation mechanism 131, 131A, 131C Housing 134, 134A, 134C Cutting disc (disc) 139, 139A, 139C opposite element 143, 252, 252C projecting section 158, 158A Sealing element 159, 159A elastic section 171, 171A, 171C variable chamber (inner chamber of the casing) 194A, 194B, 194C pin element

Claims

[1] Shock absorber (1), comprising: a cylinder (2) containing a hydraulic fluid densely packed therein; a piston (18) which is inserted smoothly and precisely into the cylinder (2) and defines a rod-side chamber (19) and a bottom-side chamber (20) in the cylinder (2); a piston rod (21) comprising an end face section which is fixed to the piston (18) in the cylinder (2) and an opposite end face section which extends out of the cylinder (2) via a rod guide (22); a damping force generation mechanism (41, 42, 197) designed to generate a damping force by moving the piston (18); a cylindrical housing (131, 131A, 131C) with a base; a separating disc (134, 134A, 134C) which is movable relative to the housing (131, 131A, 131C) and forms an inner housing chamber (171, 171A, 171C) between a bottom section (141, 141A) of the housing (131, 131A, 131C) and the separating disc (134, 134A, 134C); and a ring-shaped opposing element (139, 139A, 139C) which is provided on a side of the cutting disc (134, 134A, 134C) opposite the bottom section (141, 141A), opposite the cutting disc (134, 134A, 134C), wherein the inner circumferences of the housing (131, 131A, 131C) and the opposite element (139, 139A, 139C) are fixed by a pin element (194A, 194B, 194C) passing through them, wherein a projecting section (143, 252, 252C) is formed on the bottom section (141, 141A) of the housing (131, 131A, 131C) or the opposite element (139, 139A, 139C), wherein the projecting section (143, 252, 252C) projects towards the cutting disc (134, 134A, 134C) and is designed to restrict movement of the cutting disc (134, 134A, 134C), and wherein a sealing section (158, 158A) is provided on a projecting section (143, 252, 252C) of the cutting disc (134, 134A, 134C), wherein the sealing section (158, 158A) is designed to seal between an outer circumference of the cutting disc (134, 134A, 134C) and the inner circumference of the housing (131, 131A, 131C), wherein an elastic section (159, 159A) is provided between a surface of the separating disc (134, 134A, 134C) which is opposite a surface of the separating disc (134, 134A, 134C) on which the sealing section (158, 158A) is provided and the opposite element (139, 139A, 139C) or the bottom section (141, 141A) of the housing (131, 131A, 131C). [2] Shock absorber (1), comprising: a cylinder (2) containing a hydraulic fluid densely packed therein; a piston (18) which is inserted smoothly and precisely into the cylinder (2) and defines a rod-side chamber (19) and a bottom-side chamber (20) in the cylinder (2); a piston rod (21) comprising an end face section which is fixed to the piston (18) in the cylinder (2) and an opposite end face section which extends out of the cylinder (2) via a rod guide (22); a damping force generation mechanism (41, 42, 197) designed to generate a damping force by moving the piston (18); a cylindrical housing (131, 131A, 131C) with a base; a separating disc (134, 134A, 134C) which is movable relative to the housing (131, 131A, 131C) and forms an inner housing chamber (171, 171A, 171C) between a bottom section (141, 141A) of the housing (131, 131A, 131C) and the separating disc (134, 134A, 134C); and a ring-shaped opposing element (139, 139A, 139C) which is provided on a side of the cutting disc (134, 134A, 134C) opposite the bottom section (141, 141A), opposite the cutting disc (134, 134A, 134C), wherein the inner circumferences of the housing (131, 131A, 131C) and the opposite element (139, 139A, 139C) are fixed by a pin element (194A, 194B, 194C) passing through them, wherein a projecting section (143, 252, 252C) is formed on the bottom section (141, 141A) of the housing (131, 131A, 131C) or the opposite element (139, 139A, 139C), wherein the projecting section (143, 252, 252C) projects towards the cutting disc (134, 134A, 134C) and is designed to restrict movement of the cutting disc (134, 134A, 134C), and wherein a sealing section (158, 158A) is provided on a projecting section (143, 252, 252C) of the cutting disc (134, 134A, 134C), wherein the sealing section (158, 158A) is designed to seal between an outer circumference of the cutting disc (134, 134A, 134C) and the inner circumference of the housing (131, 131A, 131C), wherein an annular space is formed between the separating disc (134, 134A, 134C) and the housing (131, 131A, 131C) and the sealing section (158, 158A) is provided such that it is firmly attached over the space to the two surfaces of the separating disc (134, 134A, 134C). [3] Shock absorber (1) according to claim 1 or 2, wherein the housing (131, 131A, 131C) is provided on the piston (18). [4] Shock absorber (1) according to claim 1 or 2, wherein the cylinder (2) includes an inner tube (3) and an outer tube (4) on an outer circumferential side of the inner tube (3), and wherein a bottom valve (25A, 25B, 25C) is provided between the inner tube (3) and the outer tube (4) and the housing (131, 131A, 131C) is provided on the bottom valve (25A, 25B, 25C). [5] Shock absorber (1) according to claim 1 or 2, wherein the pin element (194A, 194B, 194C) is one end face section of the piston rod (21).

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