齿条是一种齿分布于条形体上的特殊齿轮。齿条也分直齿齿条和斜齿齿条，分别与直齿圆柱齿轮和斜齿圆柱齿轮配对使用； 齿条的齿廓为直线而非渐开线（对齿面而言则为平面），相当于分度圆半径为无穷大圆柱齿轮(The rack is a special gear in which the tooth is distributed on the bar. Rack is also divided into straight teeth rack and helical rack, which are paired with spur gear and helical cylindrical gear respectively. Rack profile is straight line instead of involute (for tooth face is plane), equivalent to cylindrical gear with infinite radius of indexing circle.)