Patent ID: 8840510

Claim:
A speed reduction mechanism, comprising: a speed reduction unit that includes an input member formed of an external gear that makes circular motion about a rotation axis with a predetermined eccentric amount, and a rotation force applying member formed of an internal gear that has teeth the number of which is larger than the number of teeth of the input member and that is in mesh with the input member; and a lubricating oil supply unit that supplies lubricating oil to a bearing of the speed reduction unit, wherein the bearing of the speed reduction unit is radially inward of the input member, and wherein the lubricating oil supply unit includes an oil tank arranged outside of the rotation force applying member, an oil delivery passage that delivers the lubricating oil from a space formed between the input member and the rotation force applying member to the oil tank, and a first oil introduction passage that introduces the lubricating oil from the oil tank to the bearing, and the lubricating oil is delivered from the space to the oil delivery passage through pumping action of the input member based on the circular motion.