Patent ID: 7426882

Claim:
A gear-shifting device for a manual transmission, comprising a shift arm and a shift piece, said shift arm being mounted over a shift selector shaft and being rotatable with respect to said shift selector shaft rotatable in correspondence to a shift operation of a change-lever, and said shift piece being in contact with an arm portion of said shift arm and being pushed to shift by said arm portion in correspondence to a rotation of said shift arm, said shift of said shift piece transmitting an operational force applied in said shift operation to a synchro-sleeve for a gear shift; wherein: said gear-shifting device further comprises an attenuating mechanism, which is provided in a system that transmits said operational force between said shift selector shaft and said synchro-sleeve, said attenuating mechanism attenuating a load transmitted through said shift arm to said shift selector shaft; wherein: said shift arm comprises a first shift arm, which rotates together with said shift selector shaft as a one-piece body, and a second shift arm, rotatable with respect to said shift selector shaft; said second shift arm is rotated with respect to said shift selector shaft through said attenuating mechanism, which is provided on a rotational side of said second shift arm, to attenuate said load, and wherein: said attenuating mechanism comprises an engaging groove, which is provided extending axially on a peripheral surface of said shift selector shaft, a fitting room, which is provided at part of the second shift arm that fits rotatably over said shift selector shaft and which has an opening that faces said engaging groove, a spherical body, which is placed in said fitting room to meet and engage with said engaging groove, and a resilient body, which is also placed in said fitting room to bias said spherical body toward said engaging groove; when said shift selector shaft and said second shift arm rotate with respect to each other within a predetermined angle, said spherical body being pushed against the bias of said resilient body shifts in a direction coming out of said engaging groove, allowing said second shift arm to rotate with respect to said shift selector shaft; and when said shift selector shaft and said second shift arm rotate with respect to each other beyond said predetermined angle, said spherical body shifting in said direction out of said engaging groove compresses said resilient body substantially completely, engaging said shift selector shaft and said second shift arm through said compressed spherical body for said shift selector shaft and said second shift arm to rotate together as a one-piece body.