Gears(齿轮)

Types of gears(齿轮的种类)

Gears are widely known as transmission components, being used to transfer power and change the value and direction of rotation. There are different types of gears and they can be classified into three categories according to their transmission:

齿轮是机械传动中广泛应用的传动零件,用于传递动力、改变转速和方向。齿轮的种类繁多,根据其传动情况可分为三类:

(1) Cylindrical gears(Spur gears,helical gears and herringbone gearsUsed to transmit the turning force and rotational velocity between two parallel axes (Fig. 7-23a,b andc).

(2) Bevel gears Used to transmit the turning force and rotary motion between two perpendicular axes (Fig. 7-23d).

(3) Worm and worm gears  Used to transmit the turning force and rotary motion between two perpendicular axes (Fig. 7-23e).

1)圆柱齿轮(直齿轮、斜齿轮、人字齿轮)  用于传递两平行轴间的动力和转速(图7-23 a、b、c)。

2)锥齿轮   用于传递两垂直相交轴间的动力和转速(图7-23d)。

(3)蜗杆和蜗轮   用于传递两垂直交叉轴间的动力和转速(图7-23e)。

The major component of a gear is a toothed wheel. There are related national standards for both the structure and dimension of various gears. Gears following national standards are called standard gears. Those modified on the basis of standards are called profile shifted gears. When the teeth of a pair of cylindrical mating gears are produced on cylindrical surfaces, they are called spur gears.According to their directions, gear teeth are divided into straight, skew andso on. The present chapter focuses on the main features and the drawing methods of standard spur gears.

轮齿是齿轮的主要结构,它的结构和尺寸都有国家标准。凡轮齿符合标准规定的齿轮,称为标准齿轮。在标准齿轮的基础上,对轮齿作了某些改动的齿轮,称为变位齿轮。轮齿加工在圆柱外表面上的齿轮,称为圆柱齿轮。圆柱齿轮按轮齿的方向,可分为直齿、斜齿等。本节主要介绍标准直齿圆柱齿轮的基本知识及其规定画法。