Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details

Definitions

• the present invention relates to a shock absorber that can be installed sideways.
• Patent Document 1 discloses a shock absorber that is mounted sideways and uses a pin to position the base cap and the valve body in the circumferential direction (the direction of rotation around the center line of the shock absorber) (hereinafter referred to as a "conventional shock absorber").
• An object of the present invention is to shorten the overall length of a shock absorber that is installed laterally.
• the shock absorber of the present invention is characterized by comprising a convex portion formed in the second cylinder bottom member and protruding radially outward, and a concave portion formed in the first cylinder bottom member and accommodating the convex portion.
• the shock absorber of the present invention is characterized in that it comprises a groove portion formed on the sealing surface of the second cylinder bottom member with the first cylinder bottom member, communicating the reservoir chamber with the third chamber, and a protrusion formed in the first cylinder bottom member, protruding inwardly from the groove portion.
• the overall length of the shock absorber that is installed sideways can be shortened.
• FIG. 2 is a cross-sectional view of a cylinder body of the shock absorber according to the first embodiment.
• FIG. 2 is an explanatory diagram of the first embodiment, showing a state in which a valve body is assembled to a base cap.
• FIG. 2 is an explanatory diagram of the first embodiment, and is a perspective view of a base cap.
• FIG. 2 is an explanatory diagram of the first embodiment, and is a perspective view of a valve body.
• FIG. 11 is an explanatory diagram of a second embodiment, showing a state in which a valve body is assembled to a base cap.
• FIG. 13 is an explanatory diagram of the second embodiment, and is a perspective view of a base cap.
• FIG. 11 is an explanatory diagram of a second embodiment, and is a perspective view of a valve body.
• FIG. 13 is an explanatory diagram of a third embodiment, showing a state in which a valve body is assembled to a base cap.
• FIG. 13 is an explanatory diagram of the third embodiment, and is a perspective view of a base cap.
• FIG. 13 is an explanatory diagram of a third embodiment, and is a perspective view of a valve body.
• 13 is a perspective view of a base cap having a protrusion formed thereon to serve as a marker for the installation direction of the shock absorber.
• shock absorber 1 a twin-tube horizontal bi-flow hydraulic shock absorber 1 (hereinafter referred to as "shock absorber 1”) that is mounted horizontally ("horizontally” in the first embodiment) between the body and bogie of a railway vehicle (not shown) will be described as an example.
• the right side in Fig. 1 will be referred to as “one end side”
• the left side in Fig. 1 as “the other end side”
• the left-right direction in Fig. 1 as "the axial direction of shock absorber 1”
• the up-down direction in Fig. 1 as "the up-down direction”.
• the shock absorber 1 has a cylindrical base shell 3 (first cylinder), a cylinder 2 (second cylinder) concentrically arranged within the base shell 3, and an annular reservoir chamber 4 formed between the cylinder 2 and the base shell 3.
• the shock absorber 1 has a base cap 31 (first cylinder bottom) formed at one end 5 of the base shell 3.
• the base cap 31 is formed in a cylindrical shape with a bottom, and a cylindrical portion 32 is fitted into a cap fitting portion 7 formed on the inner circumference of the end 5 of the base shell 3.
• the end 5 of the base shell 3 and the bottom 32 of the base cap 31 are joined by a full-circumference weld 8.
• An attachment member 23 to be connected to the vehicle body is joined to one end of the bottom 33 of the base cap 31.
• the shock absorber 1 has a piston 9 slidably inserted into the cylinder 2.
• the piston 9 divides the inside of the cylinder 2 into a first chamber 2A at the other end side and a second chamber 2B at one end side.
• the piston 9 has an extension side relief valve 16 that opens when the hydraulic pressure in the first chamber 2A reaches a set pressure during the extension stroke of the piston rod 10, and releases the pressure (hydraulic fluid) of the first chamber 2A to the second chamber 2B.
• the piston 9 has an extension side orifice passage 18 that generates a damping force with orifice characteristics during the extension stroke of the piston rod 10.
• the piston 9 has a compression side relief valve 17 that opens when the hydraulic pressure in the second chamber 2B reaches a set pressure during the compression stroke of the piston rod 10, and releases the pressure (hydraulic fluid) of the second chamber 2B to the first chamber 2A.
• the piston 9 has a compression side orifice passage 19 that generates a damping force with orifice characteristics during the compression stroke of the piston rod 10.
• the shock absorber 1 has a piston rod 10 with one end 11 (first end) connected to the piston 9.
• the other end 12 (second end) of the piston rod 10 is inserted into a rod guide 13 attached to the other end of the cylinder 2 and the base shell 3, and extends outside the cylinder 2.
• An attachment member 22 connected to the bogie side is joined to the end 12 of the piston rod 10.
• a cylindrical cover 26 (partially shown in Figure 1) is attached to the end 12 of the piston rod 10 to cover the piston rod 10 protruding outside from the cylinder body 25.
• the base shell 3 has a female thread (reference number omitted) formed on the inner circumference of the end portion 6 on the other end side.
• a disk-shaped lock ring 14 with a male thread (reference number omitted) formed on the outer circumference is attached to the female thread of the base shell 3.
• the shock absorber 1 generates an axial force in the cylinder 2 by tightening the lock ring 14 attached to the base shell 3 and pressing the washer 15 and rod guide 13 towards one end.
• the shock absorber 1 has a base valve 45 that controls the flow of hydraulic fluid between the second chamber 2B and the reservoir chamber 4.
• the base valve 45 has a valve body 51 (second cylinder bottom member) that divides the second chamber 2B from the reservoir chamber 4 and forms the third chamber 21 between the base cap 31 and the valve body 51.
• the valve body 51 has passages 46, 47 that communicate the second chamber 2B and the third chamber 21.
• the passage 46 is provided with a check valve 48 that allows the hydraulic fluid to flow from the third chamber 21 to the second chamber 2B.
• the passage 47 is provided with a relief valve 49 that opens when the hydraulic pressure in the second chamber 2B reaches a set pressure and releases the pressure (hydraulic fluid) of the second chamber 2B to the reservoir chamber 4 via the third chamber 21. Note that hydraulic fluid is sealed in the cylinder 2, and hydraulic fluid and gas are sealed in the reservoir chamber 4 as the hydraulic fluid.
• the valve body 51 has a fitting portion 52 that fits into the inner circumference of the end portion 20 on one end side of the cylinder 2, and a cylindrical portion 53 formed on one end side of the fitting portion 52.
• the cylindrical portion 53 has an outer diameter larger than the fitting portion 52, and a third chamber 21 is formed inside.
• annular abutment surface 54 (see FIG. 1) against which the end face on one end side of the cylinder 2 abuts.
• the end face 55 (sealing surface) on one end side of the cylindrical portion 53 of the valve body 51 abuts against the annular sealing surface 34 (see FIG. 3) formed on the bottom 33 of the base cap 31.
• the sealing surface 34 of the base cap 31 and the end face 55 of the valve body 51 are arranged on a plane perpendicular to the center line of the shock absorber 1 (hereinafter referred to as the "axis-perpendicular plane of the shock absorber 1").
• the end 20 on one end side of the cylinder 2 is positioned coaxially with the center line of the shock absorber 1 by the end on one end side of the cylindrical portion 53 of the valve body 51 being guided to the center by the inner cylindrical surface 36 formed on the outer periphery of the sealing surface 34 of the bottom 33 of the base cap 31.
• the valve body 51 has a groove 56 that extends radially (the "up-down direction" in Figure 2) on the end face 55 of the cylindrical portion 53.
• the groove 56 forms a flow passage 57 with a rectangular cross section between the end face 55 (sealing surface) of the cylindrical portion 53 and the sealing surface 34 of the base cap 31, connecting the third chamber 21 to the reservoir chamber 4.
• the groove 56 is located at the lower end of the cylindrical portion 53, and is formed symmetrically with respect to a vertical plane that includes the center line of the shock absorber 1.
• the valve body 51 has a notch 58 formed on the inner periphery of the end face 55 of the cylindrical portion 53.
• the outer periphery of the notch 58 on the end face 55 of the cylindrical portion 53 abuts against the sealing surface 34 of the base cap 31.
• the notch 58 is disposed at the upper end of the cylindrical portion 53 (diametrically opposite to the groove 56) and is formed symmetrically with respect to a vertical plane including the center line of the shock absorber 1.
• the notch 58 has a radial length equal to the width of the groove 56 (the length in the left-right direction in FIG. 2) and an axial length equal to the depth of the groove 56 (the length in the left-right direction in FIG. 1).
• the valve body 51 has a protrusion 59 that protrudes diagonally downward and radially outward.
• the protrusion 59 is disposed in a position close to a side surface 60 on one side (the "left side” in FIG. 2) of the groove 56.
• the end face (reference numeral omitted) of the protrusion 59 on one end side is disposed on the same plane as the end face 55 of the cylindrical portion 53.
• the base cap 31 has a recess 35 into which the protrusion 59 of the valve body 51 is fitted.
• the groove 56 and the protrusion 59 of the valve body 51 are disposed in a position lower than the liquid level S1 (see FIG. 2) of the hydraulic fluid sealed in the reservoir chamber 4 when the shock absorber 1 is attached sideways.
• the groove 56 and the protrusion 59 are disposed in a position lower than a horizontal plane L0 including the center line of the shock absorber 1.
• the volume of hydraulic fluid that the piston rod 10 has withdrawn from the cylinder 2 flows from the reservoir chamber 4 to the second chamber 2B via the groove 56 (flow path 57) formed in the valve body 51, the third chamber 21, the passage 46 formed in the valve body 51, and the check valve 48.
• the volume of hydraulic fluid that the piston rod 10 has entered into the cylinder 2 flows from the second chamber 2B to the reservoir chamber 4 via the passage 47 formed in the valve body 51, the relief valve 49, the third chamber 21, and the groove 56 (flow path 57) formed in the valve body 51.
• a convex portion 59 that protrudes radially outward is formed at one end of the valve body 51 (second cylinder bottom member), and the convex portion 59 is fitted into a recess 35 formed in the bottom portion 33 of the base cap 31 (first cylinder bottom portion).
• the convex portion 59 that protrudes radially outward from the valve body 51 is accommodated in the recess 35 formed in the base cap 31, thereby positioning the valve body 51 in the circumferential direction (the direction of rotation about the center line of the shock absorber 1) relative to the base cap 31.
• a pin for circumferentially positioning the valve body 51 relative to the base cap 31 is not required, so there is no need to ensure a wall thickness (axial length) for machining a fitting hole for the pin in the base cap 31 and the valve body 51, and in particular, it is possible to reduce the wall thickness of the bottom 33 of the base cap 31. Therefore, in the first embodiment, the overall length (basic length) can be shortened compared to conventional shock absorbers. Also, the effort and time required to machine a positioning pin in the base cap 31 can be reduced, reducing manufacturing costs.
• the positioning structure between the valve body 51 and the base cap 31 and the seal structure between the valve body 51 and the base cap 31 are integrated.
• the convex portion 59 (positioning structure) and the end face 55 (seal structure) of the cylindrical portion 53 can be formed on the valve body 51 by press molding, and the concave portion 35 (positioning structure) and the seal surface 34 (seal structure) can be formed on the base cap 31 by press molding. This makes it possible to further reduce manufacturing costs.
• a notch 58 of the same width as the groove 56 is formed on the end face 55 of the valve body 51.
• the notch 58 has an opening area on the end face 55 (sealing surface) of the valve body 51 that is approximately equal to the opening area of the groove 56, and the notch 58 is positioned radially opposite the groove 56. This makes it possible to equalize the pressure acting on the end face 55 (sealing surface) of the valve body 51, improves the sealing performance between the base cap 31 and the valve body 51, and stabilizes the axial force acting on the cylinder 2.
• the groove 56 (flow path 57) and protrusion 59 (positioning mechanism in the direction of rotation) of the valve body 51 are positioned lower than the liquid level S1 of the hydraulic fluid sealed in the reservoir chamber 4 (on the ground side when the shock absorber 1 is attached to the railway vehicle), so air can be prevented from entering the cylinder 2 from the reservoir chamber 4 through the gap between the groove 56 and protrusion 59 and the recess 35.
• the valve body 51 has a convex portion 59 that protrudes radially outward and vertically downward.
• the base cap 31 has a concave portion 35 (see FIG. 6) into which the convex portion 59 of the valve body 51 fits.
• the valve body 51 has groove portions 65, 66 that extend radially on the end face 55 of the cylindrical portion 53.
• the groove portions 65, 66 are arranged on both circumferential sides of the end face 55 of the cylindrical portion 53, sandwiching the convex portion 59 therebetween.
• the groove portions 65, 66 are formed symmetrically with respect to a vertical plane that includes the center line of the shock absorber 1.
• the grooves 65, 66 form flow paths 67, 68 having a rectangular cross section that communicate the third chamber 21 with the reservoir chamber 4 between the end face 55 (sealing surface) of the cylindrical portion 53 and the sealing surface 34 of the base cap 31.
• the grooves 65, 66 and the protrusion 59 of the valve body 51 are disposed at a position lower than the liquid level S1 (see FIG. 5 ) of the working fluid sealed in the reservoir chamber 4 when the shock absorber 1 is attached sideways.
• the grooves 65, 66 and the protrusion 59 are disposed at a position lower than a horizontal plane L0 including the center line of the shock absorber 1. In the second embodiment, it is possible to obtain the same effects as those of the first embodiment described above.
• the valve body 51 is formed with a convex portion 59 that protrudes radially outward, and the base cap 31 is formed with a concave portion into which the convex portion 59 fits, so that the valve body 51 is positioned in the circumferential direction (the direction of rotation about the center line of the shock absorber 1) relative to the base cap 31.
• a protrusion 71 that abuts against a side surface 60 of a groove 56 formed in the valve body 51 (second cylinder bottom member) and a protrusion 72 that abuts against a side surface 61 of the groove 56 formed in the valve body 51 are formed on the sealing surface 34 of the bottom 33 of the base cap 31 (first cylinder bottom), thereby positioning the valve body 51 in the circumferential direction (the direction of rotation about the center line of the shock absorber 1).
• the protrusion 71 has a rectangular cross section in a horizontal plane, and extends upward from the inner cylindrical surface 36 of the base cap 31 parallel to a vertical plane including the center line of the shock absorber 1.
• the protrusion 72 is formed symmetrically with respect to the protrusion 71, with the vertical plane including the center line of the shock absorber 1 as the plane of symmetry.
• the protrusions 71, 72 are arranged in a pair within the groove 56 of the valve body 51, spaced apart in the groove width direction of the groove 56 (the "left-right direction" in Figure 8).
• the protrusion 59 formed on the valve body 51 in the first embodiment can be eliminated. This eliminates the need to form the recess 35 extending radially outward on the other end (inner) surface of the bottom 33 of the base cap 31. This makes it possible to reduce the inner diameter of the cylindrical portion 32 of the base cap 31, and therefore the outer diameter of the base shell 3, and thus the shock absorber 1 can be made smaller.
• a protrusion 41 formed by press molding on the outer side of the bottom 33 of the base cap 31 (first cylinder bottom) may be used as a guide when mounting the shock absorber 1 sideways on a railway vehicle. This makes it possible to prevent the shock absorber 1 from being mounted in the wrong direction, i.e., to prevent the flow paths 57, 67, 68 from being positioned higher than the liquid level S1 (see FIG. 2) of the hydraulic fluid sealed in the reservoir chamber 4.
• the present invention is not limited to the above-described embodiments, but includes various modified examples.
• the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.
• 1 shock absorber 2 cylinder (second cylinder), 2A first chamber, 2B second chamber, 3 base shell (bottom of first cylinder), 4 reservoir chamber, 5 end portion on one end side (first end portion), 10 piston rod, 11 end portion on one end side (first end portion), 12 end portion on the other end side (second end portion), 21 third chamber, 35 recessed portion, 59 protruding portion

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fluid-Damping Devices (AREA)

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Citations (6)

• 2024
  • 2024-03-12 WO PCT/JP2024/009456 patent/WO2024262104A1/ja not_active Ceased
  • 2024-03-12 JP JP2025527466A patent/JPWO2024262104A1/ja active Pending
  • 2024-03-12 CN CN202480014645.2A patent/CN120693469A/zh active Pending

Patent Citations (6)

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