To provide an automatic tensioner capable of increasing a movement speed of a rod when absorbing the looseness of a chain so as to effectively prevent the rattling of the chain.
The automatic tensioner is constituted in such a manner that a nut member 19 is arranged in a bottomed cylinder 9 keeping one end open, the rod 10 has on its outer periphery a male thread 18 engaging with a female thread 20 formed on the inner periphery of the nut member 19, a rolling bearing 15 is mounted on a portion of the rod 10 that projects from the cylinder 9, a spring seat 16 rotatably supported by the rolling bearing 15 is urged by a return spring 17 surrounding the outer circumference of the cylinder 9 in such a direction that the rod 10 projects from the cylinder 9, and the chain 6 or belt is pressed by the spring seat 16.
ONIMARU KOICHI
Torii Kazuhisa
Takayoshi Tagawa
Yaichiro Nakatani