| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that, since a conventional EGR control valve employs an expensive PTFE seal as condensed-water intrusion prevention means for a bearing, the number of part items and man-hours become large, thus causing a cost increase.SOLUTION: An EGR control valve has at least one or more radial holes 71 for leveling a pressure difference between an A-point and a B-point around an output shaft 5 at a first protrusive shaft part 41 of the output shaft 5 which forms a clearance part 62 between a throttle wall 65 of a hosing 4 and itself, or at a large-diameter shaft part 43. By this constitution, the pressure difference in a shaft circumferential direction at the clearance part 62 formed between an internal peripheral of the throttle wall 65 of the housing 4 and an external periphery of the first protrusive shaft part 41 of the output shaft 5 is eliminated. As a result, even if the expensive PTFE seal is abolished, condensed water does not intruded into a bearing hole 61 from passage holes 22, 23 of the housing 4. |
