The two ends of the central shaft which serve as the rotation center of the caster wheel are mounted loosely, so as to letdown the noise of caster wheel rotation.

发明作为脚轮的旋转中心的中心轴的两端松弛的安装，以降低脚轮旋转时产生的噪音。

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The two ends of the central shaft which serve as the rotation center of the caster wheel are mounted loosely, so as to letdown the noise of caster wheel rotation.

发明作为脚轮的旋转中心的中心轴的两端松弛的安装，以降低脚轮旋转时产生的噪音。

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