JPH0422005Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an overhead camshaft type valve train, and more specifically, the invention relates to an overhead camshaft type valve train. This invention relates to a valve train that allows easy gap adjustment.

[Prior art]

Conventionally, an overhead camshaft type valve train employing a finger type rocker arm has one end of the rocker arm connected to the cylinder head via a rotation shaft, as disclosed in, for example, Japanese Utility Model Application Publication No. 57-191807. At the same time, an adjusting screw is provided at the other operating end, and the valve stem of the intake/exhaust valve is It was configured so that it could freely come into contact with the end.

However, in the case of such a conventional valve train, the tip of the adjuster screw is formed into a spherical surface and engages with the valve stem end, resulting in high contact stress and significant wear. There was a problem with the lack of reliability.

In order to solve the above problems, conventionally, as disclosed in Japanese Utility Model Application Publication No. 59-68105,
It has also been proposed that a cylindrical cap member is provided at the tip of the adjusting screw so as to be able to make surface contact with the valve stem end of the intake/exhaust valve. However, when a cap member such as the one described above is provided, there is a problem that the intake/exhaust valves bounce during exhaust braking, and at this time the adjustment screw is tilted and the corners are chipped, and the cap member is cylindrical. Therefore, the valve gap can only be adjusted every half turn of the adjustment screw, and only every 1/2 of the screw pitch, making it extremely difficult to adjust the valve gap.

[Purpose of invention]

This invention was devised by focusing on the conventional problems, and its purpose is to effectively prevent wear and breakage of the tips of the adjusting screws that come into contact with the valve stem ends of intake and exhaust valves. It is an object of the present invention to provide a valve train which prevents the above problems and also makes it possible to easily adjust the valve gap.

[Structure of the idea]

In order to achieve the above object, this invention forms the insertion part of the locker arm of the adjusting screw having a rectangular cross section, and has a contact member that can make line contact with the valve stem end, and also forms the insertion part of the locker arm with a rectangular cross section. The gist is that a snap spring shim is interposed in the gap.

[Example of idea]

Embodiments of this invention will be described below based on the accompanying drawings.

FIG. 1 shows a cross-sectional view of the essential parts of an overhead camshaft type valve train employing a finger-type rocker arm in which this invention has been implemented. It is rotatably supported via a moving shaft 3, and the operating end 4 on the other end side is connected to an intake/exhaust valve 7 via a contact member 6 fitted to the tip of an adjusting screw 5. The valve stem end 8 is configured to freely come into contact with the valve stem end 8 of the valve stem end 8.

Locker arm 1 of the adjustment screw 5
The shaft portion 5a inserted through one end is formed to have a square or rectangular cross section to facilitate positioning, as shown in FIG. 5b is formed in a cylindrical shape into which a snap spring shim 9 as shown in FIG. 3 can be easily inserted. Then, the shaft portion 5a of the adjuster screw 5 is inserted into the penetration portion (not shown) of the locker arm 1, and then one end of the locker arm 1 and the abutting member 6 are inserted.
After inserting the snap spring shim 9 into the portion 5b between the
This allows you to easily adjust the valve gap.

The rocker arm 1 also includes a camshaft 14 and a cam 1 provided on the upper part thereof with a roller 13 rotatably supported via a shaft 12 in the center thereof.
When the camshaft 14 rotates, it swings about the rotation shaft 3 as a fulcrum via the cam 15 and the roller 13, thereby opening the intake/exhaust valve 7.

Note that 16 is a valve stem, 17 is a valve guide, 18 is a valve head, and 19 is an intake/exhaust port.

By configuring the device as described above, this invention reduces wear on the tip of the valve stem end 8 and the tip of the adjuster screw 5, significantly improving reliability, and the adjustment of the valve gap described above is possible. Once measured with a thickness gauge, it is only necessary to insert the snap spring shim 9, making it easy to adjust the valve gap.

In addition to the embodiments described above, it is also possible to apply the present invention to an overhead camshaft type valve operating system in which the valve gap is adjusted by the rocker arm 1 and the upper end of the push rod.

[Effect of idea]

This invention forms the insertion part of the locker arm of the adjuster screw having a rectangular cross section, which is provided with the abutting member capable of making line contact with the valve stem end as described above, and the gap between the locker arm and the abutting member. In addition, a snap spring shim is installed to effectively prevent wear and breakage of the tips of the adjusting screws that come into contact with the valve stem ends of the intake and exhaust valves, as well as to facilitate valve gap adjustment. There is a possible effect.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the main parts of an overhead camshaft type valve train that employs a finger-type rocker arm based on this invention, Figure 2 is an overall perspective view of the adjuster screw, and Figure 3 is a perspective view of the adjusting screw. It is a top view of a pulling shim. 1... Rotsuka arm, 4... Operating end, 5...
Adjustable screw, 5a...Shaft part, 6
...Abutting member, 7...Intake/exhaust valve, 8...Valve stem end, 9...Snat spring shim.

Claims (1)

[Scope of utility model registration request] The insertion portion of the locker arm of the adjuster screw, which is equipped with a contact member capable of making line contact with the valve stem end, is formed to have a rectangular cross section, and a snap spring shim is interposed in the gap between the locker arm and the contact member. A valve train characterized by: