圈上泽文通大华 Helical Gears(斜齿轮) Advantages: >Quieter running >Greater strength for the same size gear. ▣ Disadvantages: >Greater cost than spur gears >Introduction of axial component of force Requires thrust bearings on the shaft. Parallel-axis helical gears used extensively in vehicle transmission Both manual and automatic-shifting >Principally because of their quiet running. 圈上泽夫道大学 Bevel Gears(锥齿轮) Bevel gears have teeth formed on conical surfaces and are used mostly to transmit motion and power between intersecting shafts. >Straight Bevel(直齿圆锥齿轮) >Spiral(螺旋锥齿轮) >Hypoid(准双曲面伞齿轮) 66  Advantages:  Quieter running  Greater strength for the same size gear.  Disadvantages:  Greater cost than spur gears  Introduction of axial component of force Requires thrust bearings on the shaft.  Parallel-axis helical gears used extensively in vehicle transmission  Both manual and automatic-shifting  Principally because of their quiet running. Helical Gears（斜齿轮）  Bevel gears have teeth formed on conical surfaces and are used mostly to transmit motion and power between intersecting shafts.  Straight Bevel（直齿圆锥齿轮）  Spiral （螺旋锥齿轮）  Hypoid （准双曲面伞齿轮） Bevel Gears （锥齿轮）