Shock absorber
A shock absorber includes a tubular outer tube, a tubular inner tube, a rod, a piston, an urging member, and a guide bush. The guide bush is a ring-shaped member arranged along an inner periphery of the outer tube, abuts against a front surface and a rear surface of the inner tube to movably hold the inner tube, and is separated from left and right side surfaces of the inner tube.
1. A shock absorber comprising:
a tubular outer tube that is connectable to either a vehicle wheel or a vehicle body;
a tubular inner tube that includes a distal end provided inside the outer tube and a terminal end being connectable to either the vehicle wheel or the vehicle body to which the outer tube is not connected, is provided so as to be movable relative to the outer tube, and is filled with oil therein;
a rod that is provided inside the inner tube and is supported by the outer tube or the inner tube;
a piston that is fixed to the rod and is configured to generate a damping force when the inner tube moves relative to the outer tube;
an urging member that is configured to urge the outer tube and the inner tube in a direction in which the outer tube and the inner tube are separated from each other; and
a guide bush that is a ring-shaped member arranged along an inner peripheral surface of the outer tube, abuts against a front surface and a rear surface of the inner tube to movably hold the inner tube, and is separated from left and right side surfaces of the inner tube,
wherein an inner peripheral surface of the guide bush has a cross-sectional shape with an axis of the inner tube as the normal direction, said cross-sectional shape being longer in a left-right direction than in a front-rear direction.
2. The shock absorber according to claim 1 ,
wherein at least when a load in a direction intersecting the axis of the inner tube is not applied, an inner peripheral surface and an outer peripheral surface of the inner tube have a circular cross-sectional shape with the axis as a normal direction, and
wherein the inner peripheral surface of the outer tube has a shape along an outer peripheral surface of the guide bush at least at a portion where the outer tube comes into contact with the guide bush fixed in the outer tube.
3. The shock absorber according to claim 2 ,
wherein as for a wall thickness of the guide bush, a thickness of portions thereof that abut against the front and rear surfaces of the inner tube is thickest, and a thickness of portions thereof that face the left and right side surfaces of the inner tube is thinnest.
4. The shock absorber according to claim 3 ,
wherein as for a wall thickness of the outer tube, a thickness of a portion thereof that faces the thickest portion of the guide bush is thickest, and a thickness of a portion thereof that faces the thinnest portion of the guide bush is thinnest.
5. The shock absorber according to claim 2 ,
wherein a material of the guide bush has a Young's modulus lower than that of a material of the inner tube.
6. The shock absorber according to claim 2 ,
wherein an inner peripheral length of the guide bush is shortest at an upper end and is longest at a lower end.
7. The shock absorber according to claim 6 ,
wherein the inner peripheral length of the guide bush continuously increases from the upper end to the lower end.
8. The shock absorber according to claim 6 ,
wherein an outer peripheral length of the guide bush is the same from the upper end to the lower end, and
wherein the wall thickness of the guide bush is the thickest at the upper end and the thinnest at the lower end.
9. The shock absorber according to claim 2 ,
wherein the vehicle wheel is a front wheel.
10. The shock absorber according to claim 1 ,
wherein as for a wall thickness of the guide bush, a thickness of portions thereof that abut against the front and rear surfaces of the inner tube is thickest, and a thickness of portions thereof that face the left and right side surfaces of the inner tube is thinnest.
11. The shock absorber according to claim 10 ,
wherein as for a wall thickness of the outer tube, a thickness of a portion thereof that faces the thickest portion of the guide bush is thickest, and a thickness of a portion thereof that faces the thinnest portion of the guide bush is thinnest.
12. The shock absorber according to claim 10 ,
wherein a material of the guide bush has a Young's modulus lower than that of a material of the inner tube.
13. The shock absorber according to claim 10 ,
wherein an inner peripheral length of the guide bush is shortest at an upper end and is longest at a lower end.
14. The shock absorber according to claim 13 ,
wherein the inner peripheral length of the guide bush continuously increases from the upper end to the lower end.
15. The shock absorber according to claim 1 ,
wherein a material of the guide bush has a Young's modulus lower than that of a material of the inner tube.
16. The shock absorber according to claim 1 ,
wherein an inner peripheral length of the guide bush is shortest at an upper end and is longest at a lower end.
17. The shock absorber according to claim 16 ,
wherein the inner peripheral length of the guide bush continuously increases from the upper end to the lower end.
18. The shock absorber according to claim 16 ,
wherein an outer peripheral length of the guide bush is the same from the upper end to the lower end, and
wherein the wall thickness of the guide bush is the thickest at the upper end and the thinnest at the lower end.
19. The shock absorber according to claim 1 ,
wherein the vehicle wheel is a front wheel.
20. A shock absorber comprising:
a tubular outer tube that is connectable to a vehicle body;
a cylindrical inner tube that is a member made of steel in which a distal end is provided inside the outer tube, is provided so as to be movable relative to the outer tube, is filled with oil and includes a terminal end being connectable to a vehicle wheel;
a rod that is provided inside the inner tube and is supported by the outer tube or the inner tube;
a piston that is fixed to the rod and is configured to generate a damping force when the inner tube moves relative to the outer tube;
an urging member that is configured to urge the outer tube and the inner tube in a direction in which the outer tube and the inner tube are separated from each other; and
a guide bush made of an aluminum-based alloy that is an elliptical ring-shaped member arranged along an inner peripheral surface of the outer tube, abuts against a front surface and a rear surface of the inner tube to movably hold the inner tube, and is separated from left and right side surfaces of the inner tube,
wherein as for a wall thickness of the guide bush, a thickness of portions thereof that abut against the front and rear surfaces of the inner tube is thickest, and a thickness of portions thereof that face the left and right side surfaces of the inner tube is thinnest, and the wall thickness of the guide bush is the thickest at an upper end, and is the thinnest at a lower end,
wherein an inner peripheral surface of the guide bush has a tapered shape, in which an inner peripheral length is shortest at the upper end, and is longest at the lower end, and
wherein an outer peripheral length of the guide bush is the same from the upper end to the lower end.