Patent ID: 8387575

Claim:
A variable valve apparatus for switching a lift amount of a valve between a time of low speed and a time of high speed, the variable valve apparatus comprising: a cam shaft supported rotatably and including, arranged around an axis thereof, a low speed cam and a high speed cam; a rocker shaft spaced from the cam shaft and extending parallel or substantially parallel to the cam shaft; a low speed rocker arm mounted on the rocker shaft to be rockable about an axis thereof, and which rocks in response to the low speed cam and pushes a stem end surface of the valve; a through-hole formed in the low speed rocker arm and arranged to be parallel or substantially parallel to the rocker shaft; a connecting pin slidably disposed in the through-hole; an actuator arranged to move the connecting pin back and forth within the through-hole; a high speed rocker arm mounted on the rocker shaft to be rockable about the axis thereof, and which rocks in response to the high speed cam; and an engaging portion arranged on the high speed rocker arm to engage the connecting pin projecting from the through-hole; wherein the low speed rocker arm includes: a first cam receiver including a slipper surface slidable on the low speed cam, and a first side surface arranged in a direction depending from an end of the slipper surface; and a first connector including a second side surface located closer to the valve than is the first side surface and arranged perpendicular or substantially perpendicular to the rocker shaft, the first connector including the through-hole; the high speed rocker arm includes: a second cam receiver including a slipper surface slidable on the high speed cam, and a third side surface arranged in a direction depending from an end of the slipper surface; and a second connector integral with the second cam receiver and including a fourth side surface in a position opposed to the second side surface of the first connector, the second connector including the engaging portion; the engaging portion includes a cylindrical engaging hole including a central axis extending axially of the rocker shaft; and the second connector includes a fifth side surface located below the fourth side surface to be further remote from the second side surface than is the fourth side surface, such that a width of the cylindrical engaging hole in a direction of the rocker shaft is narrower in a lower portion adjacent the valve than in an upper portion of the cylindrical engaging hole adjacent the slipper surface, and a guide surface located in a lower portion of the fourth side surface that defines an arc that is shorter than a semicircle and is coaxial and equal in radius with the engaging hole.