| 摘要 |
<p>PURPOSE:To prevent foreign matter in oil from being bitten in an oil pressure control valve in a variable valve timing device driven by switching an oil pressure path by the oil pressure control valve. CONSTITUTION:A variable valve timing mechanism 3 is operated by adjusting oil pressure, to oil pressure chambers 28 and 29 on both the sides of a ring gear 27 interposed between a cam shaft 1 and a pulley 2, by an oil pressure control valve (OCV) 4. An introduction port 39, discharge ports 40 and 41, and drain ports 42 and 43 are formed on the sleeve 36 of the OCV 4. A ring gear 27 is retained in the intermediate position against the drive reaction force of the cam shaft 1 by applying some hydraulic pressures to the oil pressure chamber 28 while retaining the spool 37 in neutral position. When a spool 37 is located at a neutral position, a first closing allowance S1 formed between the spool 37 and the sleeve 36 corresponding to the discharge port 41 is set relatively small to a degree where the leak flow of oil becomes much.</p> |
