Gear transmission device and robot arm using the same

A robot arm, comprising:

• a first arm,
• a second arm movably connected to the first arm;
• a gear transmission device mounted on a sidewall of the first arm, comprising a transmission mechanism, the transmission mechanism comprising a first adjusting gear and a second adjusting gear meshed with the first adjusting gear;
• and
• a gear backlash adjusting mechanism engaged with the transmission mechanism, the gear backlash adjusting mechanism comprising a fixing plate fixed on the transmission mechanism, and a first adjusting member sleeved on the first adjusting gear;
• and
• a driving mechanism mounted on the sidewall of the first arm, and driving the second arm to rotate via the transmission mechanism;
• wherein the first adjusting gear connected to the driving mechanism;
• the first adjusting gear drives the second adjusting gear to rotate;
• the fixing plate defines a first limiting hole;
• the first adjusting member comprises a flange, and the flange is received in the first limiting hole;
• a maximum distance from an edge of the flange near the second adjusting gear to a rotation shaft of the first adjusting gear is greater than a minimum distance from an end of the flange away from the second adjusting gear to the rotation shaft of the first adjusting gear;
• when rotate the first adjusting member, the first adjusting member is capable of driving the rotation shaft of the first adjusting gear to move towards a rotation shaft of the second adjusting gear.