speed changer的用法和样例：
例句
- Step Speed Changer and Magnetic Clutch to adjust the belt speed for stable feeding and spacing between blanks.
采用变速器和磁性离合器调整送纸皮带速度，确保送纸及输纸步距的稳定。 - A combination countershaft and planetary gear set transmission is provided that achieves at least nine forward speed ratios and two reverse speed ratios.
提供了组合副轴和行星齿轮组变速器，它实现了至少九个前进速比和两个后退速比。
