noun
sash roller; door roller; sliding door roller
A small wheel or roller attached to the bottom of a sliding door, window sash, or screen to allow smooth movement along a track.
古い戸車が摩耗して、障子の開け閉めが重くなった。
The old sash rollers wore out, making the sliding screen door hard to open and close.
ホームセンターで戸車を買ってきて、自分で交換した。
I bought a door roller at the hardware store and replaced it myself.