JP2528603Y2 - valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve constituting a valve train of an internal combustion engine.

2. Description of the Related Art In recent years, internal combustion engines have become increasingly sophisticated and maintenance-free due to high rotation speed and high output, and with the adoption of EGR (exhaust gas recirculation system), the lubrication conditions have become severe, while the wear resistance in the high rotation range has been increased. Is required. In response to this demand, there has been disclosed a sliding component in which ceramic having excellent wear resistance is fixed to a sliding surface of a metallic main member via a metallic joining member (Japanese Patent Application Laid-Open No. 3-46053).

[0002]

However, a valve having a sliding surface having the same structure as the sliding component disclosed in the above publication has the following problems. It is a metallic main member (valve body)
Since the protruding portion of the metallic joining member is fixed to the fitting hole by fitting, the pressure received from the outside from the cotter and the protruding portion of the metallic joining member from the inside into the groove for fixing the cotter on the valve stem. Stress concentrates due to the pressure received from it. Referring to FIG. 5, since the valve stem, which is the shaft portion, slides with the stem guide, the surface of the valve is usually carburized, nitrided, or the like, and the surface thereof is extremely hard and brittle. The cotter groove is thin and easily deformed by a pressing pressure from the inside, and stress is concentrated. An object of the present invention is to provide a valve in which stress is not concentrated on a groove for fixing a cotter that holds a retainer that is in pressure contact with a valve spring.

[0003]

The first means is that a projecting portion on the back surface of a joining member whose one end has a mushroom shape and the other end of which is brazed with a ceramic chip sliding on another surface on another component is fitted. A valve having an engagement hole formed therein and having a groove for fixing a cotter on a valve stem on the outer periphery between both ends, wherein the protrusion corresponding to the inside of the groove is provided with the fitting. A valve characterized by having at least a clearance between the hole and the hole is used. here,
Having at least a clearance between the protrusion corresponding to the inside of the groove and the fitting hole means that the protrusion of the joining member does not contact the side wall of the fitting hole corresponding to the inside of the groove. And it is good to provide a clearance mainly by providing a hollow in a joining member. It may be press-fitted regardless of whether or not the protrusion of the joining member is in contact with the side wall of the fitting hole that does not correspond to the inside of the groove.

The second means is a mushroom-shaped end,
The other end has a fitting hole on the front surface where the protrusion on the back surface of the joining member brazed with a ceramic chip that slides with other components is fitted, and the cotter is fixed on the valve stem on the outer periphery between both ends A valve, which is an on-off valve of an internal combustion engine having a groove formed therein, characterized in that a protrusion on the back surface of the joining member corresponding to the inside of the groove is fitted with a loose fit.

[0005]

The effect is that stress is not concentrated on the groove for fixing the cotter of the valve. That is, since the groove has no pressure from the fitting hole side, the stress is not concentrated only by the pressure from the cotter side, and the durability is excellent. In particular, in the second means, since the joining member is fitted with a loose fit, the joining member brazed with the ceramic chip can be set after the valve is assembled to the engine. For this reason, in the interference fit, when the outer diameter of the ceramic chip is increased, assembling is impossible because the outer diameter of the ceramic chip is caught by the stem guide at the time of mounting. However, in the loose fit, the outer diameter of the ceramic chip can be made larger than the outer diameter of the stem. Also, since it does not contact the stem guide during mounting, tight tolerances such as press-fitting are not required, the tolerance of the ceramic chip outer diameter is rough (no polishing), the sliding area that the rocker arm hits is saved, and the valve has a high lift Can respond to.

[0006]

1 to 5 show the structure of a valve according to the present invention.
This will be described with reference to FIG. The bulb 1 of the present invention has a mushroom shape 1a at one end, and a projection 1d1 on the back surface of a joining member 1d on the other end 1b of which a ceramic chip 1e slidable to another component is brazed on the surface. This is a valve of an internal combustion engine having a hole 1g and a groove 1f for fixing the cotter 2 on a valve stem 1c on the outer periphery between both ends. The valve can have the structure shown in the following embodiment so that stress is not concentrated on the groove 1f.

(First Embodiment) In the first embodiment, a clearance A is provided between the fitting hole 1g and the protrusion 1d1 by providing a recess in the protrusion 1d1 of the joining member 1d corresponding to the inside of the groove. (FIG. 1). Therefore, since the groove 1f has the clearance A, the fitting hole 1g
No pressure is applied from the side. (Second embodiment) A clearance fit is provided between the protrusion 1d1 of the joining member 1d and the fitting hole 1g (FIG. 2). Therefore, no pressure is applied to the groove 1f from the fitting hole 1g side due to the loose fit. (Third Embodiment) The structure is such that the tip of the protrusion 1d1 of the joining member 1d does not reach the inside of the groove 1f for fixing the cotter 2 (FIG. 3). Therefore, no pressure is applied to the groove 1f from the fitting hole 1g side. (Fourth Embodiment) The tip of the projection 1d1 of the joining member 1d reaches the inside of the groove 1f for fixing the cotter 2, but the tip of the projection 1d1 is tapered and corresponds to the groove 1f. 1d1
Does not touch the fitting hole 1g. Therefore, the fitting hole 1 is formed in the groove 1f.
No pressure is applied from the g side.

Next, a method of using the valve of the present invention will be described with reference to FIG. Generally, the valve mainly exists in the cylinder head 10 as an on-off valve for a combustion chamber (not shown) in the cylinder block of the engine. One end 1a of the valve 1 constitutes a part of the combustion chamber, and the valve 1 follows the cam 5 and the valve springs (4a, 4b) while sliding the valve stem 1c against the stem guide 7. Specifically, the valve 1 is pushed down by the cam 5 via the valve lifter 9, and the combustion chamber is opened. Then, the valve 1 pushed down via the cotter 2 and the retainer 3 by the valve springs (4a, 4b) is pulled up, and the combustion chamber is closed. Here, the cam 5 and the valve lifter 9
Is preferably adjusted by shims 6 having different thicknesses. The cotter 2 is fixed to the groove 1f of the valve 1, and the retainer 3 is supported on the cotter 2 by making both contact surfaces tapered.

(Experimental Example) Next, the embodiment of the above-described valve according to the present invention (1, 2)
2, 3, 4) and the valve of the comparative example were manufactured, respectively. First, an Al2O3-Y2O3-based sintering aid is added to 90% of Si3N4, a forming binder is added, and a forming binder is added. After forming by a die press, sintering is performed in a N2 atmosphere, and a Si3N4 chip having a diameter of 7.8 mm and a thickness of 1.7 mm is obtained. Was lap-polished on both sides to produce a ceramic chip having a diameter of 7.8 mm and a thickness of 1.5 mm. Next, a JISSNCM630 material was formed by forging and then processed to produce a joining member having a diameter of 7.8 mm, a thickness of 2.5 mm, and a projection of 3 mm in diameter and 5 mm in length. Then, the ceramic chip and the joining member are replaced with In.
79 in vacuum through the Cu-Ag-Ti-based active brazing material 8
Bonding was carried out at 0 ° C. for 15 minutes. The joining member to which the ceramic chip was brazed was fitted into a stem end fitting hole of a valve body (stem diameter: 8 mm) formed by forging JIS SUH3 material. The fitting allowance of the examples (1, 3, 4) was 5 to 20 μm. The valve of the comparative example has a protrusion 1d1 of the joining member 1d corresponding to the inside of the groove and a fitting hole 1g.
(Fig. 6). The fitting margin was 5 to 20 μm.

The valves having the structures of Examples and Comparative Examples were subjected to a durability test for 100 hours at a rated speed of 150% at a rated speed of 150% by using a motoring device to double the valve clearance. As a result, Example: No abnormality after 100 hours of durability. Comparative Example: Breaking from the cotter groove after 4 hours of durability. In the comparative example, the cotter is tightened on the thinner groove portion and the tensile stress due to the press-fitting is generated in the inner diameter of the press-fit portion on the valve side.

[0011]

Effect of the Invention The valve of the present invention is a valve which is excellent in durability and extremely industrially extremely useful, in particular, in which stress is not concentrated on the groove for fixing the cotter.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a valve showing a main part of the valve according to a first embodiment of the present invention.

FIG. 2 is an axial sectional view showing a main part of another embodiment of the valve according to the second embodiment of the present invention.

FIG. 3 is an axial sectional view showing a main part of another embodiment of the valve according to the third embodiment of the present invention.

FIG. 4 is an axial sectional view showing a main part of another embodiment of the valve according to the fourth embodiment of the present invention.

FIG. 5 is an axial sectional view showing a state where the valve according to the embodiment of the present invention is assembled to an engine.

FIG. 6 is an axial sectional view showing a main part of a valve of a comparative example.

[Explanation of symbols]

 1, 1 'Valve 1c Valve Stem 1d, 1d' Joint Member 1d1, 1d1 'Projection of Joint Member 1e Ceramic Chip 1f Groove 1g Fitting Hole 2 Cotta 3 Retainer 4a, 4b Spring 5 Cam 6 Shim 7 Stem Guide 8 Low Material 9 Valve lifter 10 Cylinder head A Clearance

Claims (2)

(57) [Scope of request for utility model registration] 1. One end is mushroom-shaped, and the other end has a fitting hole into which a projection on the back surface of a joining member to which a ceramic chip sliding with another component is brazed is fitted. An on-off valve for an internal combustion engine having a groove for fixing a cotter on a valve stem on an outer periphery thereof, wherein at least a clearance is provided between the protrusion and the fitting hole corresponding to the inside of the groove. Characteristic valve 2. One end has a mushroom shape, the other end has a fitting hole into which a projection on the back surface of a joining member brazed with a ceramic chip sliding on another component on the surface is fitted. In a valve which is an on-off valve of an internal combustion engine having a groove for fixing a cotter on a valve stem on the outer periphery, a protrusion on the back surface of the joining member corresponding to the inside of the groove is loosely fitted. Valve characterized by