Carrier 1 rotates about fixed axis A and is connected by a turning pair to planet gear 2 which meshes with internal gear 4 and with fixed external gear 3. When carrier 1 rotates, gear 2 rolls around gear 3, rotating gear 4 about axis A. For gears 3 and 4 to be coaxial, the numbers of teeth of gears 2, 3 and 4 should satisfy the condition z₄=z₃+2z₂. The speeds n₁ and n₄ of carrier 1 and gear 4 (in rpm) satisfy the condition n₄=n₁(z₃+z₄)/z₄ where z₃ and z₄ are the numbers of teeth of gears 3 and 4. Carrier 1 and gear 4 rotate in the same direction.
$2882$CxG,PR$