JPH057444Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rocker arm that constitutes a valve mechanism of an engine.

Traditionally, the locking arm that makes up the engine valve mechanism has been made of metal, and because it operates under high surface pressure, it is prone to abnormal wear as the engine operates, which tends to cause engine malfunction. It was big. Moreover, with the aim of saving fuel, the viscosity of the engine oil used is becoming lower and the quality of the fuel is becoming lower, and with the shift to higher compression ratios, the valve train is subjected to even harsher operating conditions. Therefore, the first
As shown in the figure, a shaft pin P is inserted into a roller R at the part where a cam (not shown) acts on one end side of the arm member A, and both ends of the shaft pin P are connected to the arm so that the roller R can freely rotate. Fit the member A so that the cam comes into contact with the surface of the roller R.
Since the cam rotates, there are some types that prevent uneven wear on the cam contact surface and increase durability. However, since a high load is applied to the roller R of such a roller-type arm, the amount of wear, especially on the shaft pin P, becomes large.Therefore, it is necessary to use a needle bearing, etc., but the structure is complicated and expensive. . Further, since the roller R is made of metal, wear of the outer circumferential surface with which the cam comes into contact is unavoidable, and as a result, there is a great possibility that the engine may malfunction.

The present invention was developed in view of the above circumstances, and the sliding surface on which the cam comes into contact is mounted by rotatably supporting both ends of a cylindrical body made of a large ceramic material with wear resistance and heat resistance. The aim is to provide a rotary arm that is durable and durable, and to provide an engine with high performance and high reliability.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

FIG. 2A shows a side view of the locker arm 1 according to the present invention, and the locker arm 1 is provided with an insertion hole 2 for a fixed shaft that rotatably supports the locker arm 1 approximately in the center, and one side is shown in the figure. A ceramic cylindrical body 4 is formed with a recess 5 in the rocker arm 1 as shown in FIG. After being inserted through the mounting holes 6a, 7a formed in the pair of convex walls 6, 7, the snap springs 8, 9 are fitted. In this case, since the diameter of the ceramic cylindrical body 4 is slightly smaller than the diameter of the mounting holes 6a and 7a, the ceramic cylindrical body 4 is rotatably supported at both ends, and rotates with the contact operation of the cam. can do. As the ceramic material constituting the ceramic columnar body 4, sintered bodies such as alumina, zirconia, silicon carbide, silicon nitride, and sialon are preferably used, and the outer circumferential surface that the cam comes into contact with is designed to avoid wear of the cam surface. It has been mirror polished.

As described above, according to the present invention, a ceramic cylindrical body is rotatably supported from both ends at the part where the cam comes into contact, and the surface of the ceramic cylindrical body is used as the cam's abutting surface. This structure provides a rocker arm with high wear resistance and mechanical strength, which reduces wear not only on the contact surface but also on the corresponding cam surface, and provides excellent sliding characteristics. This results in an engine with less mechanical loss, higher efficiency, and greater durability.

[Brief explanation of the drawing]

Figure 1A is a side view showing an example of a conventional rocker arm, Figure 1B is a sectional view taken along line X-X in Figure 1A,
FIG. 2A is a side view of the rocker arm according to the embodiment of the present invention, and FIG. 2B is a sectional view taken along the line Y--Y in FIG. 1... Locker arm, 4... Ceramic cylindrical body, 6, 7... Convex wall, 8, 9... Snap spring.

Claims (1)

[Scope of utility model registration request] A ceramic cylindrical body with a mirror-finished outer circumferential surface is inserted into a recess formed at the part of the arm member that the cam comes into contact with and a mounting hole drilled in the convex walls on both sides of the recess, and a snap ring is fitted into the mounting hole. A rocker arm for an engine, characterized in that both ends of the ceramic cylinder body are rotatably supported.