To improve muffling performance and suction efficiency, by adding to a lead valve one or both of acoustic resonance energy determined by sizes of a suction hole and a reflecting plate and acoustic resonance energy determined by size of a branch pipe, and by controlling vibration amplitude.
In a compressing process when a piston 12 lifts up, a lead valve 15 closes, the suction gas in a duct 17 is blocked rapidly, the internal pressure increases, and the refrigerant gas flows from an opening 19' into a refrigerant passing branch pipe 19. In a next suction process, the pressure in a cylinder becomes negative, immediately the refrigerant gas is supplied from the refrigerant passing branch pipe 19 and is charged into the cylinder effectively. In addition, using energy generated at an acoustic resonance frequency determined by the length of a branch pipe 19, vibration amplitude of the lead valve 15 is controlled. When opening/closing timing of the lead valve is suitable in relation to the rotational angle of a crankshaft 9, vibration amplitude of the lead valve becomes larger cause by acoustic energy, the amount of the charged gas increases, and therefore, muffling performance is improved.
UMEOKA IKUTOMO
KITA ICHIRO
ODA MASATAKA
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