Gears and Gear Ratios bowlesphysics（齿轮和齿轮比率bowlesphysics）.pdf

Gears and Gear Ratios Introduction to Robotics Gears – What are they? Gears are wheels with teeth. Gears mesh together and make things turn. Gears are used to transfer used to transfer motionmotion or or powerpower from from one moving part to another. Gears – The Purpose Gears are generally used for one of four different reasons: • To reverse the direction of rotation •• To increase or decrease the speed of rotation To increase or decrease the speed of rotation • To move rotational motion to a different axis • To keep the rotation of two axis synchronized Gears – The Purpose Sports cars go fast (have speed) but cannot pull any weight. Big trucks can pull heavy loads (have power), but cannot (have power), but cannot go fast. Gears cause this. Gears increase or decrease the power or speed, but you cannot generally speaking. Types of Gears Spur gears are gears in the same plane that move opposite of each other because they are meshed together. Gear ‘A’ is called the ‘driver’ because this is turned by a motor. As gear ‘A’ turns it meshes with gear ‘B’ and it begins to turn as well. Gear ‘B’ isgear ‘B’ and it begins to turn as well. Gear ‘B’ is called called the ‘driven’ gear. Gear Details(Spur) The circle marked in red shows the outer limit of the teeth whilst the green circles are known as the pitch circles. The pitch circle of a gear is very important as it is used by engineers to determine the shape of the determine the shape of the teeth and the ratio between