Chain tensioning device

A chain tensioning device comprising:

• a main body configured to be mounted to a bicycle;
• a chain guide pivotally coupled to the main body to rotate around a rotational axis with respect to the main body;
• a rotary fluid damper unit operatively connected between the main body and the chain guide to provide rotational resistance to the chain guide around the rotational axis, the rotary fluid damper unit being a separate unit from the main body, the rotary fluid damper unit including an outer member that is detachably fixed to the main body and an inner member that is detachably fixed to the chain guide, the inner member being rotatably disposed inside of the outer member to define a fluid cavity that is filled with a fluid;
• and
• at least one fluid flow limiting valve configured to form a flow path between the fluid flow limiting valve and one of the outer member and the inner member, the at least one fluid flow limiting valve being configured to move radially as the inner member rotates relative to the outer member about the rotational axis,
• the at least one fluid flow limiting valve including a first slanted surface facing in a first circumferential direction and a second slanted surface facing in a second circumferential direction, which is opposite to the first circumferential direction with respect to the rotational axis,
• the first slanted surface being arranged to be forced radially inward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in a first rotational direction, and the second slanted surface being arranged to be forced radially outward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in a second rotational direction, which is opposite to the first rotational direction.

A chain tensioning device comprising:

• a main body configured to be mounted to a bicycle;
• a chain guide pivotally coupled to the main body to rotate around a rotational axis with respect to the main body;
• a rotary fluid damper unit operatively connected between the main body and the chain guide to provide rotational resistance to the chain guide around the rotational axis, the rotary fluid damper unit being a separate unit from the main body, the rotary fluid damper unit including an outer member that is detachably fixed to the main body and an inner member that is detachably fixed to the chain guide, the inner member being rotatably disposed inside of the outer member to define a fluid cavity that is filled with a fluid;
• and
• at least one fluid flow limiting valve configured to form a flow path between the fluid flow limiting valve and one of the outer member and the inner member, the at least one fluid flow limiting valve including a first fluid flow limiting valve and a second fluid flow limiting valve, the first fluid flow limiting valve being configured to form a first flow path between the first fluid flow limiting valve and the outer member, and the second fluid flow limiting valve being configured to form a second flow path between the second fluid flow limiting valve and the inner member,
• each of the first and second fluid flow limiting valves including a first slanted surface facing in a first circumferential direction and a second slanted surface facing in a second circumferential direction, which is opposite to the first circumferential direction with respect to the rotational axis,
• the first slanted surface of the first fluid flow limiting valve being arranged to be forced radially inward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in a first rotational direction, and the second slanted surface of the first fluid flow limiting valve being arranged to be forced radially outward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in a second rotational direction, which is opposite to the first rotational direction, and
• the first slanted surface of the second fluid flow limiting valve being arranged to be forced radially inward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in the second rotational direction, and the second slanted surface of the second fluid flow limiting valve being arranged to be forced radially outward by the fluid in the cavity as the inner member rotates relative to the outer member about the rotational axis in the first rotational direction.