US 6,460,496 B2 · Valve timing control device

Abstract

A valve timing control device includes a purge path communicating between a hydraulic chamber allowing the entry of hydraulic pressure on starting an engine and a backward pressurized section in an accommodation hole. When the hydraulic chamber allowing the entry of hydraulic pressure on starting the engine is the retardation side hydraulic chamber, a hydraulic pressure derived from an oil pump is supplied to the retardation side hydraulic chamber on starting the engine. On the way, air-mixed oil is discharged to outside of the device by way of a purge path, a backward pressurized section in the accommodation hole and the discharge hole. When the air is discharged, a residual pressure is produced in the backward pressurized section due to oil supplied thereto. The residual pressure results in the increase of an unlocking hydraulic pressure to prevent a locking member from being unlocked. When the application of a retardation side hydraulic pressure is switched to that of an advance side hydraulic pressure, the pressure presses a front end of a locking member against only a biasing force of a biasing means to unlock a locking relation. The valve timing control device allows the use of any kinds of locking pins, and prevents the occurrence of beat noise (abnormal noise) when air-mixed oil unlocks a locking relation on starting the engine.

Claims19

Dependent claims

A valve timing control device, comprising:

a first rotor rotatable in synchronization with a crankshaft of an internal-combustion engine and having a plurality of shoes formed at an inner periphery of the first rotor;
a second rotor fixed at an end of an intake or exhaust camshaft of the internal-combustion engine, arranged in the first rotor, rotatable relative to the first rotor, and having a plurality of vanes formed at an outer periphery of the second rotor;
an advance side hydraulic chamber and a retardation side hydraulic chamber formed between the vanes of the second rotor and the shoes of the first rotor;
a locking member locking either of the first and second rotors with respect to the remainder at a required angle;
an accommodation hole arranged at either of the first and second rotors, accommodating the locking member and a biasing means biasing the locking member, and having a discharge hole discharging a backward pressure exerted on a back section of the locking member to outside;
and
an engagement hole arranged at the remainder, allowing the insertion of the locking member;
an unlocking hydraulic chamber;
and
an unlocking hydraulic pressure supply path supplying a hydraulic pressure to the unlocking hydraulic chamber;
wherein at least one of the advance and retardation side hydraulic chambers is equipped with a purge path communicating to the atmosphere.

8 more elements

Dependencies are inferred from the claim text.

Valve timing control device

Life of this patent

Valve timing control device

Life of this patent

Abstract

Claims19