US 5,724,929 AGranted

Engine variable valve timing mechanism

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsKazuhisa Mikame, Ken Asakura, Tatsuo Iida

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Abstract

A variable valve timing mechanism is provided at the distal end of a camshaft for changing a valve timing of an engine valve. A rotor is fixed to the distal end face of the camshaft, and the rotor has four vanes protruding radially outward. A housing is disposed to surround the rotor to be rotatable relative to the rotor and the camshaft, and the housing has recesses on the inner circumference. Each recess is divided by the vane into a first pressure chamber and a second pressure chamber. A first passage is defined in the camshaft, for supplying a hydraulic fluid pressure to the first pressure chamber so as to change the rotational phase of the second rotor with respect to the camshaft, and the first passage has an opening at the distal end face of the camshaft. A second passage is defined in the camshaft, for supplying a fluid pressure to the second pressure chamber so as to change the rotational phase of the second rotor with respect to the camshaft, and the second passage has an opening at outer circumference of the camshaft.

Claims20

Dependent claims

An apparatus for adjusting valve timing of a valve of an engine, the valve being actuated by a cam, the apparatus comprising:

a camshaft for driving the cam, the camshaft having a circumferential surface and a first end, wherein the first end has an end face;
a first rotor fixed to the end face of the camshaft, the first rotor having radially extending vanes;
a second rotor arranged to surround the first rotor and to be rotatable relative to the first rotor, the second rotor having a recess formed therein, the recess being divided by the vane into a first pressure chamber and a second pressure chamber;
a first passage defined in the camshaft, for supplying hydraulic fluid to the first pressure chamber to change the rotational phase of the second rotor with respect to the camshaft, the first passage having an upstream end and a downstream end with respect to the direction of fluid flow during filling of the first hydraulic chamber, the first passage having a downstream opening in the end face;
and
a second passage defined in the camshaft for supplying hydraulic fluid to the second pressure chamber to change the rotational phase of the second rotor with respect to the camshaft, the second passage having an upstream end and a downstream end with respect to the direction of fluid flow during filling of the second hydraulic chamber, the second passage having a downstream opening in a surface of the camshaft other than the end face.

3 more elements

An apparatus for adjusting the valve timing of an engine valve with respect to a crankshaft, the valve being actuated by a cam, the apparatus comprising:

a rotatable shaft, the rotatable shaft having a circumferential surface and a first end, wherein the first end has an end face;
a first rotor rotatably mounted to the first end such that the first rotor is coaxial to the rotatable shaft;
a second rotor mounted coaxially to the first end of the rotatable shaft such that the second rotor is rotatable relative to the first rotor, wherein one of the first and second rotors is fixed in locked synchronism with the crankshaft and the other is fixed to rotate in locked synchronism with the cam such that relative rotation between the two rotors changes the timing of the valve with respect to the crankshaft;
hydraulic actuation means for causing relative movement between the rotors, wherein a vane is formed on one of the rotors, and a recess is formed in the other of the rotors, such that the vane divides the recess into first and second hydraulic chambers;
a first passage formed in the rotatable shaft for supplying hydraulic fluid to the first hydraulic chamber for rotating the first rotor in a first direction with respect to the second rotor, the first passage having an upstream end and a downstream end with respect to the direction of fluid flow during filling of the first hydraulic chamber, wherein the first passage has a downstream opening in the end face;
a second passage formed in the rotatable shaft for supplying hydraulic fluid to the second hydraulic chamber for rotating the first rotor in a second direction with respect to the second rotor, the second passage having an upstream end and a downstream end with respect to the direction of fluid flow during filling of the second hydraulic chamber, wherein the second passage has downstream opening in a surface of the rotatable shaft other than the end face, and wherein the downstream opening of the second passage is radially further from the axis of the rotatable shaft than the downstream opening of the first passage.

3 more elements

Dependencies are inferred from the claim text.