Why did Yong Zhengdi change his brother's name?

This was changed after the new emperor ascended the throne to avoid his anonymity. Yong Zhengdi's name is, so all his brothers should avoid the word "Yin". The Qing dynasty since Kangxi was like this:

Kangxi's name was Michelle Ye, and his brother Xuangaiyuan.

Yongzheng was created, and his younger brother Yin changed his mind.

Gan Long is famous for its great calendar. Brother Hong changed to Hong.

Jiaqing's name is parallel lines, and brothers' parallel lines will change forever.

Daoguang's real name, brother Min changed it to encourage.

However, later generations of Yi, Zai and Pu don't know why, but only avoid the latter word, not the former word.