Patent ID: 8292836

Claim:
A walking assistance comprising: a load transmit portion which transmits load for supporting a part of the weight of a user to a body trunk of the user; a foot-worn portion to be attached to a foot of the user, a leg link which connects the foot-worn portion to the load transmit portion, the leg link including an upper link member extended from the load transmit portion through the intermediary of a first joint, a lower link member extended from the foot-worn portion through the intermediary of a second joint, and a third joint bendably connecting the upper link member and the lower link member; and a drive mechanism which includes an actuator and transmits the motive power output from the actuator to the third joint so as to drive the third joint, wherein the leg link is provided with an elastic member which imparts, to the third joint, an urging torque for restraining a flexion degree of the leg link from changing from a first flexion degree due to gravity acting on the walking assistance device in a reference state wherein at least the foot-worn portion is in contact with a ground and the flexion degree of the leg link at the third joint is a predetermined first flexion degree, wherein the flexion degree of the leg link can be changed in a predetermined variable range including the flexion degree in a state wherein the user is in an upright posture, and the first flexion degree is a flexion degree which is closer to the flexion degree in the state wherein the user is in the upright posture than a maximum flexion degree in the variable range, and wherein the urging torque to be imparted to the third joint by the elastic member is set such that the resultant torque of a torque which acts on the third joint due to the gravity acting on the walking assistance device in a state wherein at least the flexion degree of the leg link becomes the maximum flexion degree in the variable range and the urging torque becomes a torque in the flexing direction of the leg link.