JPH01193009A - Rocker arm device for 4-cycle engine - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a rocker arm device by setting a lateral hole in a rocker shaft which supports one side rocker arm, therein inserting a hydraulic tappet provided with a pivot on its top for making the pivot to support the base end of the other side rocker arm. CONSTITUTION:The central part of a rocker arm 9 which is designed to open and close exhaust valves of an internal combustion engine is pivotally mounted to the rocker shaft 10 supported on a cylinder head 1. The base end of rocker arm 9 is brought in contact with the cam 12 of a cam shaft 11 and its tip, in contact with the upper edge of the valve 7 respectively. A lateral hole 16 is formed in addition to an oil supply hole 14 and an air vent hole 15 in the axial direction along the rocker shaft 10. A hydraulic tappet 18 provided with a pivot 17 on its top is inserted in this lateral hole 16. Then the base end of the other rocker arm 19 in an intake valve 5 is supported on the pivot 17, and the upper face of the rocker arm 19 is brought in contact with the cam 12 beside its top end is brought in contact with the upper end of the intake valve 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a rocker arm device for a four-stroke engine.

[Conventional technology and its problems]

A four-cycle engine uses a cam on a camshaft that rotates in conjunction with the crankshaft to swing a rocker arm, which opens umbrella-shaped intake and exhaust valves by pushing them down against a spring. There is. There are two types of rocker arms: an end-pivot type in which the base end is supported on a pivot, and a seesaw type in which the middle part is supported on a rocker shaft. In addition, the rocker arm is equipped with an adjuster that screws in an adjustment screw and adjusts its position to adjust the gap between the valve and the valve, but since it takes time to adjust, the rocker arm is supported on the hydraulic tappet. Some valves use hydraulic tappets to automatically adjust the valve clearance using hydraulic pressure. For example, see Utility Model Publication No. 60-162204 and Japanese Patent Publication No. 49-15162. When using a hydraulic tappet, it is necessary to provide a hole in the cylinder head to insert the hydraulic tappet, and to communicate the oil supply hole and air vent hole drilled in the cylinder head with this hole.
The shape of the cylinder head is complicated, and there are structural limitations due to the provision of oil supply holes and air vent holes.
This has the disadvantage that the shape and cutting of the cylinder head become complicated, which significantly increases manufacturing costs.

[Purpose of the invention]

In this invention, a rocker shaft that pivotally supports one rocker arm is provided with an oil supply hole and an air vent hole, as well as a horizontal hole, and a hydraulic tappet with a pivot at the upper end is inserted into the horizontal hole, and the other rocker arm is attached to the rocker shaft. The four-wheeled J Renningin 0 has its end supported on a pivot, and by not installing a hydraulic tappet on the cylinder head or providing an oil supply hole, the shape of the cylinder head can be easily cut and manufacturing costs can be reduced. The purpose is to obtain a Tsuka-arm device.

(Structure of the invention) Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

The cylinder head 1 is provided with an intake hole 3 and an exhaust hole 4 that communicate with the combustion chamber 2, and at the end of the intake hole 3, a medium-sized intake valve 5 is movable and is pressed by a spring 6. Similarly, an exhaust valve 7 is provided at the end of the exhaust hole 4 so as to be slid open against a spring 8.

One of the rocker arms 9 on the pulp 7 side is of a seesaw type, and its middle part is pivoted on a rocker shaft 10 that is mounted on the cylinder head 1, its base end is in contact with the cam 12 of the camshaft 11, and its tip is in contact with the upper end of the valve 7. It is designed to apply to
A hydraulic tappet 13 is provided at the corresponding part. The rocker shaft 10 is provided with an oil supply hole 14 and an air vent hole 15 in the axial direction. A horizontal hole 16 is also provided, into which a hydraulic tappet 18 having a pivot 17 at its upper end is inserted. The pivot 17 supports the base end of the other rocker arm 19 of the intake valve 5. The tip of the rocker arm 19 is placed on the upper end of the intake valve 5, and its upper surface is in contact with the cam 12 of the camshaft 11.

[Action of the invention]

Cam 1 of camshaft 11 is linked to the crankshaft.
2 rotates, the rocker arm 19 is swung around the pivot 17, and the intake valve 5 is pushed down and opened.

Also, a rocker arm 9 pivotally supported on the rocker shaft 10
, and push down the exhaust valve 7 to open it. Oil from an oil pump linked to the crankshaft is pumped into the oil supply hole 14 of the rocker shaft 10, pushing up the hydraulic tappet 18 and reducing the gap between the rocker arm 19 and the valve 5 to zero! Section IIWJ. Since the horizontal hole 16 into which the hydraulic tappet 18 is inserted, the oil supply hole 14 and the air vent hole 15 are provided on the shaft 10, the cylinder head 1
The number of built-up parts for oil holes provided in the cylinder head 1 is reduced, the shape of the cylinder head 1 is simplified, casting work and cutting work are simplified, and costs can be significantly reduced.

(Effects of the Invention) As explained above, the present invention provides a rocker shaft that pivotally supports one rocker arm with an oil supply hole and an air vent hole drilled in the axial direction, a horizontal hole in the rocker shaft, and an oil supply hole. and the air vent hole; a hydraulic tappet with a pivot at its upper end was inserted into the horizontal hole, and the base end of the other rocker arm was supported by the pivot, so the hydraulic tappet could be attached to the rocker shaft. The shape of the cylinder head can be made simple, the casting work and cutting work can be simplified, and a large cost reduction can be achieved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1. 9... Rocker arm, 10... Rocker shaft, 14... Oil supply hole, 15... Air vent hole, 16
...Horizontal hole, 17... Pivot, 18... Hydraulic tappet, 19... Rocker arm.

Claims (1)

[Claims] An oil supply hole and an air vent hole are drilled in the axial direction on the rocker shaft that pivotally supports one rocker arm, a horizontal hole is provided on the rocker shaft to communicate with the oil supply hole and the air vent hole, and the upper end of the rocker shaft is provided with a horizontal hole that communicates with the oil supply hole and the air vent hole. 1. A rocker arm device for a four-cycle engine, characterized in that a hydraulic tappet with a hydraulic tappet is inserted, and the base end of the other rocker arm is supported by the pivot.