| 摘要 |
<p>A variable geometry turbocharger comprises a slide mechanism which includes a converter to change rotary movement of a driveshaft 21 into advancing and retreating movement of an exhaust inlet wall, the driveshaft is connected to a servo piston 31 of a hydraulic servo drive device 30 via a second converter which has a slider 29 located in a groove 32 on an outer circumference of the servo piston. The hydraulic drive device has a housing 33 in which a servo piston is slidably located, a pilot spool 36 housed in a centre hole 34 of the servo piston slides due to a change in pressure of pilot pressure oil. A first hydraulic chamber 47 and a second hydraulic chamber 48 to and from which pressure oil flows are provided in the housing. The servo piston separately includes a pressure port 51 for introducing pressure oil from an outside, a first piston port 53 for intercommunicating the centre hole and the first hydraulic chamber, a second piston port 54 for intercommunicating the centre hole and the second hydraulic chamber, and a return port 52 for exiting pressure oil.</p> |
