如何格式化Pandas / Matplotlib图形，使x轴刻度仅为小时和分钟？

import pandas as pd
import matplotlib.pyplot as plt

data = {'时间': ['2022-01-01 09:00:00', '2022-01-01 09:15:00', '2022-01-01 09:30:00', '2022-01-01 09:45:00'],
        '数值': [10, 20, 15, 25]}
df = pd.DataFrame(data)

df['时间'] = pd.to_datetime(df['时间'])

fig, ax = plt.subplots()
ax.plot(df['时间'], df['数值'])

ax.xaxis.set_major_locator(plt.MaxNLocator(6))  # 设置最大刻度数量为6
ax.xaxis.set_major_formatter(plt.DateFormatter('%H:%M'))  # 设置刻度格式为小时和分钟

plt.show()