Patent ID: 7540266
Filing Date: 2009-06-02
Classification: F01L,F16H

Abstract:
1. A variable valve actuation mechanism comprising a valve actuation mechanism main body and a rotary-to-linear actuator, wherein the valve actuation mechanism main body changes a valve parameter of an engine valve, which is either an intake valve or an exhaust valve, through linear motion of a drive shaft along an axial direction, and wherein the rotary-to-linear actuator causes the drive shaft to move linearly, wherein the valve actuation mechanism main body includes a control shaft functioning as the drive shaft, a slider gear that is displaced while being interlocked with the control shaft, an input gear, and an output gear, the input gear rotating the slide gear by torque transmitted from a camshaft of the engine valve, and the output gear causing the engine valve to move linearly along an axial direction through the rotation of the slider gear, wherein the slider gear has an input helical spline and an output helical spline, the input helical spline being engaged with a helical spline formed on the input gear, and the output helical spline being engaged with a helical spline formed on the output gear, wherein the helix direction of the tooth trace of the input helical spline is opposite to the helix direction of the tooth trace of the output helical spline, wherein the input gear includes a gear main body having the helical spline and an input arm that moves integrally with the gear main body when receiving torque of the camshaft, wherein the output gear includes a gear main body having the helical spline and an output arm that moves integrally with the gear main body by rotation of the slider gear, thereby causing the engine valve to move linearly, wherein the actuator includes an output shaft for transmitting linear motion to the control shaft, and a conversion mechanism that converts rotational motion of a motor to linear motion and causes the output shaft to move linearly along the axial direction, wherein the variable valve actuation mechanism: changes the valve parameter in accordance with a difference of relative rotational phase between the input arm and the output arm about the control shaft; changes the difference of relative rotational phase between the input arm and the output arm by changing relative positions of the slider gear and the input and output gears in the axial direction; and changes relative positions of the slider gear and the input and output gears in the axial direction through linear motion of the control shaft, wherein one of the input helical spline and the output helical spline is formed as a gear of left hand helix, and the other is formed as a gear of right hand helix, and wherein, when a moving direction of the control shaft in which relative rotation of the input gear and the output gear increases the difference of relative rotational phase between the input arm and the output arm is defined as a reference direction, a front end of the control shaft in the reference direction is connected to the output shaft of the actuator.