| 摘要 |
PROBLEM TO BE SOLVED: To provide a needle-driving device of a dewing machine which device can prevent the pressure fluctuation of the inside of the upper needle-bar- supporting part caused by driving the needle bar. SOLUTION: The needle-driving device (10) of a sewing machine has a needle bar (30), an upper needle-bar-supporting part (21), which is supporting the needle bar slidably in an opening (21a) placed in a sawing machine frame (1) an formed in the longitudinal direction, a needle-driving axis (40) rocked around the axis, a needle-driving arm (50), which is jointed with the needle-driving axis at one end and with the needle bar at the other and a box body (23) covering the opening. The needle bat has a connecting hole (31) which is connecting a space (a cylinder room 32) formed by the box body and the needle bar in the opening and the inside of the frame of the sewing machine. Therefore, when the needle bar is driven, the air in the opening and the air in the frame of the sawing machine move through the connecting hole. Accordingly the pressure fluctuation of the inside of the upper needle-bar-supporting part can be prevented.
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