JPS6329124Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fixing device for a rocker arm shaft in a valve operating mechanism that opens and closes intake and exhaust poppet valves of a reciprocating internal combustion engine.

Conventionally, the rocker arm shaft that swingably supports the rocker arm of the valve mechanism is screwed and fixed to the engine case, so that the rocker arm is rotated due to repeated violent rocking movements of the rocker arm caused by the operation of the valve mechanism. The rocker arm shaft may be rotated to some extent, which may cause wear and deformation of the rocker arm shaft, or the screwing of the rocker arm shaft may become loose, causing oil leakage.

The main object of the present invention is to provide a fixing device for a rocker arm shaft in a valve mechanism for a reciprocating internal combustion engine, which has a simple structure and eliminates the above-mentioned disadvantages.

In order to achieve the above object, the present invention provides a shaft fitting hole with a locking step on one side of the opposing support walls of the engine case, and a shaft insertion hole on the other side on the same axis. A rocker arm shaft that swingably supports a rocker arm is fitted and inserted between the shaft fitting hole and the shaft insertion hole, and a set screw that closes the open end of the hole is screwed into the shaft insertion hole. In addition, a resilient spring is interposed between the opposing surfaces of the set screw and the base end of the rocker arm shaft to resiliently force the rocker arm shaft so that the end surface of the distal end of the shaft is pressed against the locking step. It is characterized by

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a cylinder head 1 that constitutes a part of an engine case C has a valve port 3 that communicates with a combustion chamber 2, and a poppet valve 4 (intake valve or exhaust valve) that opens and closes this valve port 3. It is fitted and inserted via a guide 5 so as to be slidable up and down.

A valve mechanism A for opening and closing the poppet valve 4 is provided on the cylinder head 1. Next, to explain the structure of this valve mechanism A, there is a gap between a valve seat surface 6 formed on the cylinder head 1 and a valve seat body 8 fitted to the upper end of the poppet valve 4 via a bolt 7. , valve springs 9, 10 are compressed, and the resilient force of these valve springs 9, 10 biases the poppet valve 4 in the valve closing direction. Support walls 11, 1 integrally formed with the cylinder head 1 on one side of the poppet valve 4
2 includes a rocker arm shaft 13 as will be detailed later.
is fixed approximately horizontally, and this rocker arm shaft 13
The base end of the rocker arm 14 is rotatably supported, and the rocker arm 14 is supported on the rocker arm shaft 13.
It can swing up and down around the center. An adjustment screw 15 is attached to the nut 1 at the tip of the rocker arm 14.
6, the adjusting screw 15
The lower end of the poppet valve 4 is brought into contact with the upper end of the poppet valve 4.
On the rocker arm 14, the cylinder head 1
A camshaft 17 is rotatably supported on the camshaft 17, and a cam surface of a valve drive cam 18, which is integrated with the camshaft 17, is attached to the receiving surface 14a on the rocker arm 14 and the valve springs 9, 1.
When the valve operating cam 18 rotates, the rocker arm 14 swings downward against the spring force of the valve springs 9 and 10, and the poppet valve 4 is opened.

Next, the fixing device for the rocker arm shaft 13 according to the present invention will be explained mainly with reference to FIG. The support wall 11 is provided with a dead-end shaft fitting hole 20, and the other support wall 12 is provided with a shaft insertion hole 21 with a larger diameter on the same axis L-L. A locking step portion 20a is formed in the hole 20, and the shaft insertion hole 21
A female thread 21a is cut into the outer half of the holder.
A distal end portion 13a and a head or base end portion 13b of a rocker arm shaft 13 that swingably supports the rocker arm 14 are fitted and supported in the shaft fitting hole 20 and the shaft insertion hole 21, and the locking step portion The end face of the distal end portion 13a of the rocker arm shaft 13 is engaged with the rocker arm shaft 13 to regulate its axial position. Further, the base end portion of the rocker arm shaft 13, that is, the head portion 13b is recessed into the shaft insertion hole 21, and the shaft insertion hole 21 is further recessed.
A resilient spring, such as a disc spring 22, is inserted into the rocker arm shaft 13, and the disc spring 22 is seated on the end surface of the base end 13b of the rocker arm shaft 13. A set screw 23 is screwed into the female thread 21a from the open end of the shaft insertion hole 21, and the inner end surface of the set screw 23 is pressed against the disc spring 22, compressing the disc spring 22, and tightening the rocker arm shaft 13. The shaft 13 is fixed by being biased in one direction in the axial direction.

An O-ring 24 is interposed between the outer surface of one of the support walls 12 and the setscrew 23 to seal the space between the support wall 12 and the setscrew 23 oil-tightly.

Next, the operation of one embodiment of the present invention will be explained.

Rotation of the valve train cam 18 due to operation of the internal combustion engine;
In cooperation with the elastic force of the valve springs 9 and 10, the rocker arm 14 swings up and down around the rocker arm shaft 13 to open and close the poppet valve 4. At this time, the rocker arm 14 swings violently up and down. Repeating this, the rocker arm shaft 13 that supports this
is biased to one side (to the right in FIG. 2) by the elastic force of the disc spring 22 supported by the set screw 23, and the end surface of its tip 13a is engaged and crimped to the locking stepped portion 20a, so that the locking arm 14 The rocker arm shaft 13 does not rotate unduly even when subjected to a rocking torque, and as a result, almost no wear of the bearing portion of the rocker arm shaft 13 due to the rotation occurs.

As described above, according to the present invention, a shaft fitting hole having a locking step is formed on one side of the opposing support walls of the engine case, and a shaft insertion hole is formed on the other side on the same axis. A rocker arm shaft that swingably supports a rocker arm is fitted between the shaft fitting hole and the shaft insertion hole, and a set screw that closes the open end of the hole is screwed into the shaft insertion hole, A resilient spring is interposed between the opposing surfaces of the set screw and the base end of the rocker arm shaft, and the resilient spring springs the rocker arm shaft so that the end face of the distal end of the shaft is pressed against the locking step. The tip of the rocker arm shaft can be crimped and fixed to the locking step of the shaft fitting hole by the elastic force of the elastic spring, and the rocker arm shaft will not rotate unnaturally even if the rocker arm repeatedly swings violently. As a result, it is effective to prevent wear and deformation of the bearing portion of the rocker arm shaft, and the rocker arm shaft can always be fixed at a predetermined proper position, so that the rocker arm can always be accurately oscillated. In addition, the elastic force of the elastic spring absorbs even the slightest abrasion that occurs between the end face of the locking arm shaft and the locking step, and also acts to prevent the set screw from loosening. This can contribute to the simplification of the structure since the locking means can be omitted. In addition, the set screw, which is prevented from loosening by the elastic force, always effectively seals the open end of the shaft insertion hole, and does not cause oil leakage in the engine case.

[Brief explanation of the drawing]

FIG. 1 is a side view of a valve mechanism of an internal combustion engine equipped with the device of the present invention, and FIG. 2 is a cross-sectional view taken along the line shown in FIG. 1. C...Engine case, L-L...Same axis line, 1
1, 12...Support wall, 13...Rocker arm shaft, 13
a... Tip portion, 13b... Base end portion, 14... Locker arm, 20... Shaft fitting hole, 20a... Locking step portion, 21...
Shaft insertion hole.

Claims (1)

[Scope of utility model registration request] Opposing support walls 11, 1 of engine case C
A shaft fitting hole 2 having a locking step portion 20a on one side of the shaft fitting hole 2.
0 and the other side with the shaft insertion hole 21 on the same axis line L.
A rocker arm shaft 13 is drilled on L and swingably supports a rocker arm 14 across the shaft fitting hole 20 and the shaft insertion hole 21, and the rocker arm shaft 13 is inserted into the shaft insertion hole 21. A set screw 23 that closes the open end of the locker arm shaft 13 is screwed in, and the locker arm shaft 13 is connected to the distal end 13a of the shaft 13 between the opposing surfaces of the set screw 23 and the base end 13b of the rocker arm shaft 13. A fixing device for a rocker arm shaft in a valve operating mechanism of a reciprocating internal combustion engine, characterized in that a resilient spring 22 is interposed so that the end face is resiliently pressed against the locking step portion 20a.