JPH0223766Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a poppet valve device used for intake and exhaust valves in internal combustion engines.

In order to prevent uneven wear of the valve seat in a valve train, it is necessary to rotate the poppet valve, but when the poppet valve rotates when seated, wear due to friction between the poppet valve and the valve seat is accelerated. Furthermore, if the impact force is large when the valve is seated, the poppet valve and valve seat may be worn out or damaged. When the valve seat or poppet valve wears out, there is no gap between the poppet valve and the cam or rocker arm, and the valve remains pressed down, resulting in a reduction in engine output.

Therefore, in view of the above-mentioned problems, the purpose of the present invention is to restrict the rotation of the poppet valve when the poppet valve is seated, and to alleviate the impact force, and to allow the poppet valve to rotate freely except when the poppet valve is seated. An object of the present invention is to provide a poppet valve device for an internal combustion engine that works to prevent uneven wear of a seat.

For this reason, the configuration of the present invention is such that a buffer member is supported on one of the valve stem of the poppet valve and a valve guide that guides the valve stem, and the buffer member supports the valve stem and the valve immediately before the poppet valve is closed. It is designed so that it collides with the other of the guides.

To explain the present invention based on an embodiment, as shown in FIG. 1, a poppet valve 4 supported by a cylinder head 2 is given reciprocating motion by a valve mechanism such as a cam or rocker arm driven by an engine. . A cylindrical valve guide 3 is press-fitted into the cylinder head 2, and a valve seal 15 is secured to the upper end of the valve guide 3 by a retaining ring 16. A valve stem 5 of a poppet valve 4 is slidably inserted into this valve guide 3, and a split type kotatsu 13 that engages with a groove 17 is held in the upper part of the valve stem 5 from both sides, and a retainer 12 having a tapered hole is removed. be fitted.

A spring 10 is interposed between the retainer 12 and the wall of the cylinder head 2. A tappet 14 that contacts the cam is supported at the upper end of the valve stem 5 via a shim 21. A valve seat 9 is provided at the intake/exhaust port of the cylinder head 2, on which the poppet valve 4 is seated by the force of the spring 10 described above.

According to the invention, the poppet valve 4 is provided with a spring 10.
In order to reduce the impact force on the valve seat 9, a buffer member 6 is fitted to the valve stem 5, and the valve stem 5
It is fixedly supported by a step portion 18 formed in . As shown in FIG. 2, the buffer member 6 is made up of a cylindrical portion 7 and a large number of spring pieces 8 that are divided so as to expand upward and radially outward from the cylindrical portion 7. The cylindrical portion 7 of the buffer member 6 is fitted and fixed to the valve stem 5. on the other hand,
A groove similar to a serration is formed in the conical lower end of the valve guide 3 to abut against the spring piece 8 and prevent the poppet valve 4 from rotating.

Next, the operation of the device of the present invention will be explained. In the state shown in FIG. 1 in which the poppet valve 4 is pushed down by a cam or the like against the force of the spring 10, the buffer member 6 is separated from the lower end of the valve guide 3.
The poppet valve 4 can freely rotate about the axis of the valve stem 5.

When the poppet valve 4 is pushed up by the force of the spring 10, before the poppet valve 4 is seated on the valve seat 9,
The spring piece 8 of the buffer member 6 engages with a groove provided in the lower end of the valve guide 3, and rotation of the poppet valve 4 is prevented. As the poppet valve 4 rises, the spring piece 8 of the buffer member bends against the wall 19 of the cylinder head, thereby alleviating the impact when the poppet valve 4 is seated on the valve seat 9.

In the embodiment shown in FIG. 3, the buffer member 6 is press-fitted to the lower end of the valve guide 3, and a ring 2 whose upper half has a conical shape is placed above the step 18 of the valve stem 4.
0 is fitted and fixed. In this embodiment, before the poppet valve 4 is seated on the valve seat 9, the ring 20
is engaged with the spring piece 8 of the buffer member 6, and the poppet valve 4
rotation is prevented. Next, the spring pieces 8 of the buffer member 6 are expanded and bent by the ring 20, thereby alleviating the impact force when the poppet valve 4 is seated on the valve seat 9.

In this embodiment, the conical surface of the ring 20 is provided with a large number of grooves extending in the axial direction, or instead of having a conical surface, the ring 20 is tapered as a whole and has a polygonal horizontal cross section. It is preferable.

According to the present invention, as described above, when the poppet valve 4 is pushed open by the valve mechanism, the buffer member 6 provided on one of the valve guide and the valve stem and the engaging portion provided on the other Since the lower ends of the valve guide 3 or the ring 20 are separated from each other, the poppet valve 4 can freely rotate around the axis of the valve stem 5, so that the relationship between the poppet valve 4 and the valve seat 9 is The contact position changes, and uneven wear of the valve seat 9 can be prevented. Also, just before the poppet valve 4 closes, due to the collision between the buffer member 6 and the engaging portion,
The rotation of the poppet valve 4 is regulated, and the impact when the poppet valve 4 is seated on the valve seat 9 can be alleviated, resulting in excellent effects such as being able to suppress the settling of the poppet valve 4. It will be done.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a poppet valve device for an internal combustion engine according to a first embodiment of the present invention, FIG. FIG. 3 is a side cross-sectional view of a poppet valve device of such an internal combustion engine. 2: Cylinder head, 3: Valve guide, 5: Valve stem, 6: Buffer member, 8: Spring piece, 9: Valve seat, 1
0: Spring, 20: Ring.

Claims (1)

[Scope of utility model registration request] A buffer member is supported on one of the valve stem of the poppet valve and a valve guide that guides the valve stem, and the buffer member is applied to the other of the valve stem and the valve guide immediately before the poppet valve is closed. 1. A poppet valve device for an internal combustion engine, characterized in that the poppet valve device is configured to fit together.