Abstract: A hydraulic shock absorber which includes a piston which is slidably fitted into a cylinder and partitions the cylinder into first and second fluid chambers; and a piston rod which is connected to the piston and slidably penetrates through an end wall of the cylinder, wherein the piston rod penetrates through the piston and includes on the outer circumferential surface of the piston rod at least one groove which communicates between the first and second fluid chambers, and the first and second fluid chambers are communicated with each other through the at least one groove.

Abstract: A damper unit includes: a cylinder, connected to a reservoir; a piston dividing an interior of the cylinder into two chambers; a piston rod which is connected to the piston at one end; an inner sleeve adapted to be accommodated within a hollow recess portion in the piston rod; a pump rod; a pump unit which performs pumping for generating a force with which the piston is pushed out of the cylinder or the piston is drawn into the cylinder; a hydraulic fluid releasing unit configured to release the a hydraulic fluid within the inner sleeve and the pump rod to the reservoir or the two chambers when the piston reaches a predetermined position relative to the cylinder within a sliding range thereof by pumping of the pump unit; and a control unit configured to control the predetermined position where the hydraulic fluid is released.

Abstract: A variable damping-force damper includes a cylinder tube filled with magnetic particles (MRF), a piston that is slidably disposed within the cylinder tube, a piston rod connected with the piston and is disposed so as to protrude out of one end of the cylinder tube and a rod guide that closes one end of the cylinder tube and slidably supports the piston rod. The cylinder tube has a Ni plating film whose Vickers hardness is 800 VHN or more on its inner peripheral surface and the piston slides relative to the Ni plating film. The rod guide has a structure having a predetermined base material portion and a fluorine resin contained Ni plating film that is treated by heat and is provided on the surface of the base material portion. The piston rod slides relative to the fluorine resin contained Ni plating film.

Abstract: In a magneto-rheological variable damper (6), the piston (16) comprises an inner yoke (32), an outer yoke (31) concentrically surrounding the inner yoke and held in position by pair of end plates (33, 34) made of non-magnetic material and disposed on either axial end surfaces of the piston. The piston may be circumferentially surrounded by a piston cover (30) that may be made of non-magnetic material and serves a slide member that engages the inner circumferential surface of a cylinder (12). Alternatively, the end plates may serve as the slide member. In either case, the durability of the damper can be improved by using a wear resistant material for the slide member. In particular, the outer yoke may be made of material such as Permendur which has a high saturation magnetic flux density but a poor mechanical property. Thereby, the range of the damping force can be expanded.

Abstract: In a variable damper using magneto-rheological fluid that comprises a cylinder (12) filled with the fluid, a piston (16) slidably received in the cylinder and including an inner yoke (32; 62; 126), an outer yoke (31; 64, 65; 140) and a coil (34; 130), a piston rod (13) having an inner end attached to the piston and an outer end extending out of the cylinder and a magnetic valve formed in a gap between the inner and outer yokes, at least one of the outer yoke and inner yoke consisting of at least two parts that are joined to each other in an axial direction. The two piece arrangement of the inner yoke or outer yoke allows the end plates to be omitted because the gap spacer can be installed without requiring end plates, and this contributes to a compact design and a favorable damping property. Also, the manufacturing and servicing of the damper can be simplified. When end plates (134) are used, the freedom in the positioning of the coil is increased.

Abstract: A damper unit includes: a cylinder, connected to a reservoir; a piston dividing an interior of the cylinder into two chambers; a piston rod which is connected to the piston at one end; an inner sleeve adapted to be accommodated within a hollow recess portion in the piston rod; a pump rod; a pump unit which performs pumping for generating a force with which the piston is pushed out of the cylinder or the piston is drawn into the cylinder; a hydraulic fluid releasing unit configured to release the a hydraulic fluid within the inner sleeve and the pump rod to the reservoir or the two chambers when the piston reaches a predetermined position relative to the cylinder within a sliding range thereof by pumping of the pump unit; and a control unit configured to control the predetermined position where the hydraulic fluid is released.

Abstract: A hydraulic shock absorber which includes a piston which is slidably fitted into a cylinder and partitions the cylinder into first and second fluid chambers; and a piston rod which is connected to the piston and slidably penetrates through an end wall of the cylinder, wherein the piston rod penetrates through the piston and includes on the outer circumferential surface of the piston rod at least one groove which communicates between the first and second fluid chambers, and the first and second fluid chambers are communicated with each other through the at least one groove.

Abstract: A reduction gear includes a rotatable carrier, a ring gear rotatably fitted in an offset supporting hole in the carrier, and first and second sun gears having first and second outer teeth meshed with first and second inner teeth of the ring gear, respectively. The rotation of the carrier is reduced in speed and outputted as relative rotation of the first and second sun gears. Thus, it is possible to secure a large reduction ratio although in a small structure having a small number of components. Also, it is possible to change the reduction ratio by a slight design change of the number of teeth in one or both of the outer teeth of the first and second sun gears, thereby improving the versatility.

Abstract: A variable damping-force damper includes a cylinder tube filled with magnetic particles (MRF), a piston that is slidably disposed within the cylinder tube, a piston rod connected with the piston and is disposed so as to protrude out of one end of the cylinder tube and a rod guide that closes one end of the cylinder tube and slidably supports the piston rod. The cylinder tube has a Ni plating film whose Vickers hardness is 800 VHN or more on its inner peripheral surface and the piston slides relative to the Ni plating film. The rod guide has a structure having a predetermined base material portion and a fluorine resin contained Ni plating film that is treated by heat and is provided on the surface of the base material portion. The piston rod slides relative to the fluorine resin contained Ni plating film.

Abstract: In a magneto-rheological variable damper (6), the piston (16) comprises an inner yoke (32), an outer yoke (31) concentrically surrounding the inner yoke and held in position by pair of end plates (33, 34) made of non-magnetic material and disposed on either axial end surfaces of the piston. The piston may be circumferentially surrounded by a piston cover (30) that may be made of non-magnetic material and serves a slide member that engages the inner circumferential surface of a cylinder (12). Alternatively, the end plates may serve as the slide member. In either case, the durability of the damper can be improved by using a wear resistant material for the slide member. In particular, the outer yoke may be made of material such as Permendur which has a high saturation magnetic flux density but a poor mechanical property. Thereby, the range of the damping force can be expanded.

Abstract: In a variable damper using magneto-rheological fluid that comprises a cylinder (12) filled with the fluid, a piston (16) slidably received in the cylinder and including an inner yoke (32; 62; 126), an outer yoke (31; 64, 65; 140) and a coil (34; 130), a piston rod (13) having an inner end attached to the piston and an outer end extending out of the cylinder and a magnetic valve formed in a gap between the inner and outer yokes, at least one of the outer yoke and inner yoke consisting of at least two parts that are joined to each other in an axial direction. The two piece arrangement of the inner yoke or outer yoke allows the end plates to be omitted because the gap spacer can be installed without requiring end plates, and this contributes to a compact design and a favorable damping property. Also, the manufacturing and servicing of the damper can be simplified. When end plates (134) are used, the freedom in the positioning of the coil is increased.

Abstract: A reduction gear includes a rotatable carrier, a ring gear rotatably fitted in an offset supporting hole in the carrier, and first and second sun gears having first and second outer teeth meshed with first and second inner teeth of the ring gear, respectively. The rotation of the carrier is reduced in speed and outputted as relative rotation of the first and second sun gears. Thus, it is possible to secure a large reduction ratio although in a small structure having a small number of components. Also, it is possible to change the reduction ratio by a slight design change of the number of teeth in one or both of the outer teeth of the first and second sun gears, thereby improving the versatility.