US 9,810,281 B2
Damping force control type shock absorber
Shunsuke Mori, Yokohama (JP); Fumiyuki Yamaoka, Sagamihara (JP); and Mikio Yamashita, Yokohama (JP)
Assigned to HITACHI AUTOMOTIVE SYSTEMS, LTD., Ibaraki (JP)
Appl. No. 14/910,823
Filed by HITACHI AUTOMOTIVE SYSTEMS, LTD., Ibaraki (JP)
PCT Filed Aug. 11, 2014, PCT No. PCT/JP2014/071204
§ 371(c)(1), (2) Date Feb. 8, 2016,
PCT Pub. No. WO2015/020227, PCT Pub. Date Feb. 12, 2015.
Claims priority of application No. 2013/166592 (JP), filed on Aug. 9, 2013.
Prior Publication US 2016/0195152 A1, Jul. 7, 2016
Int. Cl. F16F 9/46 (2006.01)
CPC F16F 9/465 (2013.01) 4 Claims
OG exemplary drawing
 
1. A damping force control type shock absorber comprising a cylinder having a hydraulic fluid sealed therein, a piston slidably fitted in the cylinder, a piston rod connected to the piston and extended to an outside of the cylinder, and a damping force generating mechanism generating a damping force by controlling a flow of hydraulic fluid induced by sliding movement of the piston in the cylinder;
the damping force generating mechanism including a normally-open solenoid valve operated by energization of a coil to control the flow of hydraulic fluid, and a fail-safe valve provided upstream or downstream of the solenoid valve, the fail-safe valve being movable independently of the solenoid valve;
the fail-safe valve having a valving element movable between a normal position where the valving element opens a flow path of the hydraulic fluid and a fail-safe position where the valving element controls the flow of hydraulic fluid to generate a damping force, the fail-safe valve further having a seat part with respect to which the valving element selectively seats and unseats, a guide part movably guiding the valving element, an urging member urging the valving element toward the fail-safe position, and a magnetic attraction part magnetically attracting the valving element through a magnetic field of the coil to move the valving element to the normal position;
the seat part and the guide part being made of a non-magnetic material not forming a magnetic path through the magnetic field of the coil, and the valving element and the magnetic attraction part being made of a magnetic material forming a magnetic path through the magnetic field of the coil,
the entire portion of the seat part and the entire portion of the guide part being disposed outside an area defined by the magnetic path through the magnetic field of the coil.