Valve opening-closing timing control apparatus

A valve opening-closing timing control apparatus comprising:

• a driving-side rotor that rotates around a rotation axis in synchronization with a crankshaft of an internal combustion engine;
• a driven-side rotor that is arranged coaxially with the rotation axis and on an inner side of the driving-side rotor and rotates integrally with a camshaft for opening and closing a valve of the internal combustion engine;
• and
• a phase adjustment mechanism that sets a relative rotation phase between the driving-side rotor and the driven-side rotor, wherein
• the phase adjustment mechanism includes:
• an output gear that is provided at the driven-side rotor in such a way as to be coaxial with the rotation axis;
• an input gear that rotates around an eccentric axis in an orientation parallel to the rotation axis and is connected to the driving-side rotor;
• a tubular eccentric member that supports the input gear from an inner circumferential side and allows the input gear to rotate;
• a first bearing that is arranged between an inner circumference of the driven-side rotor and an outer circumference of the eccentric member;
• a second bearing that is arranged between an inner circumference of the input gear and an outer circumference of the eccentric member and on a side farther from the camshaft than the first bearing in a direction along the rotation axis;
• and
• an elastic member that is arranged between an outer circumferential side of the eccentric member and an inner circumferential side of the second bearing and along a circumferential direction of the eccentric member and applies biasing force to the input gear in such a way as to cause a part of the input gear to mesh with a part of the output gear,
• rotation of the eccentric member causes the eccentric axis to revolve and thereby changes a position where the output gear meshes with the input gear,
• the eccentric member includes one first concave portion formed on an outer circumferential surface along the circumferential direction,
• the elastic member includes:
• a supported portion that is supported by a bottom surface of the first concave portion;
• an elastically deformable portion that is supported by the supported portion and generates the biasing force;
• and
• a biasing portion that is supported by the elastically deformable portion and applies the biasing force to the input gear,
• the elastic member is accommodated in the first concave portion, and is supported by the first concave portion at two different locations in the circumferential direction,
• the elastic member is constituted of a pair of spring members accommodated in the first concave portion, and
• the pair of spring members each include the supported portion, the elastically deformable portion, and the biasing portion.