# US 2017/0284497 A1 · Shock absorber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0284497 A1 - Document ID: US20170284497A1 - Status: Published application - Kind: A1 - Application number: 15/434,633 - Filed: 2017-02-16 - Published: 2017-10-05 - Earliest claimed: 2016-03-30 - Assignees: Showa Corporation - Applicants: Showa Corporation - Inventors: Tadashi UOTANI; Koji TOKUNAGA - Web page: https://patentgrep.com/patent/US20170284497A1 ## CPC - F16F 9/34: Special valve constructions ({F16F9/44, F16F9/50 take precedence; filtering details F16F9/3285} ; valves in general F16K); Shape or construction of throttling passages - B62K 25/283: {for cycles without a pedal crank, e.g. motorcycles} - F16F 9/185: {Bitubular units (where compression of gas leads to a clear spring action F16F9/062)} - F16F 9/3257: {in twin-tube type devices} - B62K 2201/04: Helical springs - F16F 9/062: {Bi-tubular units} - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - B62K: CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE ## Abstract One embodiment provides a shock absorber. The shock absorber includes a reservoir communication path through which a damping force generator and a reservoir communicate with each other, a compression-side communication path through which a piston-side oil chamber and the damping force generator communicate with each other, and a compression-side inlet port which is provided in the damping force generator and into which oil flows from the compression-side communication path and which has a compression-side valve that generates damping force. The cross-sectional area of the reservoir communication path is smaller than the cross-sectional area of the compression-side inlet port. ## Claims ### Claim 1 A shock absorber comprising: a cylinder which has an outer tube and an inner tube provided on an inner side of the outer tube in a radial direction at an interval from the outer tube, and in which oil is sealed; a piston rod of which one end is inserted into the cylinder and the other end is extended outside the cylinder; a piston which is connected to the one end of the piston rod and is provided in the inner tube so as to be slidable along a central axis direction of the inner tube, and which partitions an inner space of the inner tube into a rod-side oil chamber closer to the piston rod and a piston-side oil chamber on an opposite side to the piston rod; a damping force generating unit which controls flow of the oil occurring when the piston slides in the inner tube according to a displacement of the piston rod, to generate damping force; a reservoir that compensates the oil according to a change in advancement volume of the piston rod into the cylinder; a reservoir communication path through which the damping force generating unit and the reservoir communicate with each other; a compression-side communication path through which the piston-side oil chamber and the damping force generating unit communicate with each other; and a compression-side port which is provided in the damping force generating unit, into which the oil flows from the compression-side communication path, and which has a compression-side valve that generates the damping force, wherein a cross-sectional area of the reservoir communication path is smaller than a cross-sectional area of the compression-side port. ### Claim 2 (depends on 1) The shock absorber according to claim 1, wherein a cross-sectional area of the compression-side communication path is equal to or larger than the cross-sectional area of the compression-side port. ### Claim 3 (depends on 1) The shock absorber according to claim 1 wherein the damping force generating unit includes: a compression-side piston having the compression-side port; and a damper cylinder that accommodates the compression-side side piston, and wherein a cross-sectional area between the compression-side side piston and the damper cylinder into which the oil flows from the compression-side communication path is equal to or larger than the cross-sectional area of the compression-side port and is equal to or smaller than the cross-sectional area of the compression-side communication path. ### Claim 4 (depends on 3) The shock absorber according to claim 3, wherein a compression-side port inlet portion is formed in the compression-side side piston on an inlet side of the compression-side port so as to be open to an outer circumferential surface of the compression-side side piston, and wherein an opening area of the compression-side port inlet portion is larger than the cross-sectional area of the compression-side port. ### Claim 5 (depends on 1) The shock absorber according to claim 1, further comprising: an extension-side communication path through which the damping force generating unit and an annular passage formed between the outer tube and the inner tube communicate with each other, wherein a cross-sectional area of the extension-side communication path is larger than the cross-sectional area of the reservoir communication path. ### Claim 6 (depends on 5) The shock absorber according to claim 5, wherein the cross-sectional area of the annular passage is equal to or larger than the cross-sectional area of the extension-side communication path. ### Claim 7 (depends on 5) The shock absorber according to claim 5, further comprising: an oil hole which is formed in the inner tube so as to allow communication between the annular passage and the rod-side oil chamber, wherein a cross-sectional area of the oil hole is equal to or larger than the cross-sectional area of the annular passage. ### Claim 8 (depends on 5) The shock absorber according to any one of claim 5, wherein the damping force generating unit further includes: an extension-side piston having an extension-side port into which the oil having flowed from the extension-side communication path into the damping force generating unit flows; and a compression-side outlet port into which the oil having passed through the compression-side port of the compression-side side piston flows, wherein a cross-sectional area between the damper cylinder and the extension-side piston is larger than the cross-sectional area of the reservoir communication path. ### Claim 9 (depends on 8) The shock absorber according to claim 8, wherein the cross-sectional area of the compression-side outlet port is equal to or larger than the cross-sectional area between the damper cylinder and the extension-side piston. ### Claim 10 (depends on 8) The shock absorber according to claim 8, wherein a compression-side outlet port inlet portion is formed in the extension-side piston on an inlet side of the compression-side outlet port so as to be open to an outer circumferential surface of the extension-side piston, and wherein an opening area of the compression-side outlet port inlet portion is larger than a cross-sectional area of the compression-side outlet port.