Abstract: A valve timing adjusting device includes a housing, a vane rotor, a sleeve, and a spool. The housing includes a timing pulley connected to a crank shaft through a dry belt, and rotates in association with the crank shaft. The sleeve includes a supply port, a drain port, a first control port, a second control port, and a first drain oil channel. The spool includes an oil connection channel that is arranged at an axial center portion of the spool and controls the supply port to be connected with the first control port or the second control port depending on an axial-direction position. The drain port is connected with a first drain space through a second drain oil channel. A second drain space is connected with the first drain space through a third drain oil channel that is provided to span the vane rotor and the cam shaft.

Abstract: A spool has a connection passage that connects a supply port and a discharge port with each other according to a position of the spool in an axial direction. A valve seat is arranged in the connection passage. The connection passage has a supply hole passing through the spool in a radial direction, and a discharge hole passing through the spool in the radial direction. The spool has a guide surface that guides a valve object to move in the axial direction while restricting a position of the valve object in the radial direction. The discharge hole is opened on the guide surface.

Abstract: A valve timing adjusting device includes a housing, a vane rotor, a sleeve, and a spool. The housing includes a timing pulley connected to a crank shaft through a dry belt, and rotates in association with the crank shaft. The sleeve includes a supply port, a drain port, a first control port, a second control port, and a first drain oil channel. The spool includes an oil connection channel that is arranged at an axial center portion of the spool and controls the supply port to be connected with the first control port or the second control port depending on an axial-direction position. The drain port is connected with a first drain space through a second drain oil channel. A second drain space is connected with the first drain space through a third drain oil channel that is provided to span the vane rotor and the cam shaft.

Abstract: A spool has a connection passage that connects a supply port and a discharge port with each other according to a position of the spool in an axial direction. A valve seat is arranged in the connection passage. The connection passage has a supply hole passing through the spool in a radial direction, and a discharge hole passing through the spool in the radial direction. The spool has a guide surface that guides a valve object to move in the axial direction while restricting a position of the valve object in the radial direction. The discharge hole is opened on the guide surface.

Abstract: A main locking mechanism locks a phase at a main locking phase, at which an intake valve is closed at timing later than a bottom dead center, by inserting a main locking member into a main locking hole. A sub locking mechanism locks a phase at a sub locking phase advanced more than the main locking phase by inserting a sub locking member into a sub locking hole. A movable body disposed in the main locking hole reciprocates between an open position and a blocking position of the main locking hole. During a warm start of an engine, a driving source maintains the movable body at the open position at which the inserting of the main locking member into the main locking hole is maintained. In contrast, during a cold start of the engine, the driving source drives the movable body to the blocking position at which the main locking member is removed from the main locking hole.