JPH0727362Y2 - Rocker arm adjustment mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a rocker arm for driving intake / exhaust valves and the like, and more particularly to a rocker arm adjustment mechanism for finely adjusting the drive amount of the rocker arm.

[Prior Art] As a proposal for suitably operating a rocker arm that drives an intake / exhaust valve, there is a previous proposal of the present applicant, "a rocker arm adjustment mechanism" (Japanese Patent Application No. 63-72293).

In this proposal, as shown in FIG. 3, a cap c that abuts the stem end of the intake / exhaust valve is swingably fitted to the tip of an adjustment screw b for fine adjustment attached to a rocker arm a, and the adjustment is performed. The tip end d of the screw b is formed as a curved surface that rolls on the smooth inner bottom e of the cap c, and constitutes a "rocker arm adjustment mechanism".

According to this structure, when the inner bottom of the cap is formed into a smooth surface, the rocking fulcrum of the spherical head and the cap when the rocker arm is driven comes to be positioned on the upper side of the cap, and as a result, it is smooth. The tip of the spherical head moves relative to the surface in trochoidal curve motion.

When the inner bottom of the cap is formed as a smooth surface and the cap and the spherical surface of the spherical head are formed as curved surfaces, relative movement between the cap and the spherical head becomes smoother, and wear of the spherical head ( Fretting wear) can be suppressed.

[Problems to be Solved by the Invention] However, in order to further reduce the surface fatigue of the spherical head to reduce the load capacity of the spherical head, the spherical head having a large radius of curvature must be formed, This is not preferable because it causes the cap to become larger.

[Means for Solving the Problems] The present invention is intended to solve the above problems, and a spherical head for swingably fitting a cap that abuts against the rear end of a valve rod is formed at the tip of an adjusting screw of a rocker arm. Then
A rocker arm adjusting mechanism is configured by interposing a curved sheet member having a smooth spherical head side and a cap side rolling on the inner bottom between the head and the smooth inner bottom of the cap. .

[Operation] When the adjusting screw is swung relative to the cap, the seat member rolls on the inner bottom of the insert member in accordance with the swing. That is, at the same time that the sheet member makes a curvilinear motion of rolling on a smooth surface, the spherical portion also makes a curvilinear motion on the smooth surface of the sheet member. As a result, the swing angle of the adjusting screw is the sum of the swing angle of the seat member and the swing angle of the spherical portion.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

Reference numeral 1 shown in FIG. 1 denotes a rocker arm that is driven by a cam or tappet or the like, and an adjusting screw 5 having a spherical head portion 4 integrally at the tip is screwed onto an arm 2 that is the point of action of the rocker arm 1. Is provided. A cap 8 that abuts a rear end 7 of a valve rod 6 such as an intake or exhaust valve is swingably fitted to the spherical head 4.

In the embodiment, the cap 8 has an inner peripheral surface in order to slidably fit the distal end side of the peripheral spherical surface portion 9 of the spherical head 4 as shown in FIGS. 1 and 2. Inside of the cap body 15, an insert member 11 formed in a tubular shape with a predetermined curvature in 10, a cup-shaped cap body 15 that integrally fits the insert member 11 to form a smooth inner bottom 14, And a seat member 16 that is housed in the cap body 15 to substantially increase the swing angle of the cap body 15. However, the spherical part at the tip
13 is formed with a large radius of curvature with respect to the spherical surface portion 9 on the circumferential side. On the other hand, the cap 8 has an inner peripheral surface.
10 is formed by a curved surface formed by a circumferential continuation of a trochoidal curve in the Z-axis direction with respect to the triaxial directions of X, Y and Z, and the circumferential side spherical surface portion 9 of the spherical head portion 4 that slides on the curved surface. Is also formed by a curved surface consisting of a series of trochoidal curves in the Z-axis direction.

The sheet member 16 is formed in a substantially convex lens shape in the embodiment, and rolls on the smooth inner bottom 14 formed by the cap body 15 as shown in FIGS. 1 and 2. A smooth surface 18 that relatively rolls the curved surface 17 and the spherical portion 13 is formed. The sheet member 16 has the spherical portion 13
And the inner bottom 14 of the insert member 11 are provided.
However, in the embodiment, the radius of curvature of the curved surface 17 of the seat member 16 is set to be approximately the same as the radius of curvature of the spherical portion 13, and in terms of wear resistance, the seat member 16 relative to the insert member 11 is used.
Also, a certain hardness difference is provided between the sheet member 11 and the spherical surface portion 13.

By the way, on the outer peripheral side of the upper portion of the cap body 15, a bent portion 19 for crimping the upper portion of the cap body 15 and integrating the insert member 11 with the cap body 15 is integrally formed along the circumferential direction. A lip portion 21 that defines the swing limit of the cap 8 is formed on the upper portion of the peripheral spherical surface portion 9 of the insert member 11.

The relative movement of the adjusting screw 5 with respect to the cap 8 will be described below.

As shown in FIG. 1, when the adjusting screw 5 is swung relative to the cap 8, the seat member
11 rolls on the inner bottom 14 of the cap body 15. That is, as shown in FIG. 2, the sheet member 11 performs a trochoidal curve motion in which the sheet member 11 rolls on the smooth surface 14. On the other hand, spherical part 13
Also moves trochoidally on the smooth surface 18 of the seat member 16 so as to roll on the seat member 16. Therefore, the swing angle α as the adjusting screw 5 is the swing angle β of the seat member 16 and the spherical surface portion 13. And the swing angle γ of.

In the description of this embodiment, one sheet member 16 is provided, but as long as the limit height of the cap 8 is satisfied, one or more sheet members 16 may be provided in series. Naturally, it is possible to increase the swing angle of the adjusting screw 5. However, in this case, it is natural that the heights of the spherical portion 4 and the sheet member are made as small as possible.

[Effect of the Invention] As is clear from the above description, the present invention exhibits the following excellent effects.

A spherical head for swingably fitting a cap that abuts the rear end of the valve rod is formed at the tip of the adjuster screw of the rocker arm, and contacts the spherical head between the spherical head and the smooth inner bottom of the cap. Since the curved surface-shaped seat member with the smooth surface and the cap side rolling on the inner bottom is interposed, it is possible to smoothly perform the trochoidal movement of the cap with respect to the spherical head that performs the trochoidal movement, while the adjustment screw swings. The dynamic angle can be increased.

[Brief description of drawings]

FIG. 1 is a schematic view showing a preferred embodiment of the present invention, FIG. 2 is a detailed view of essential parts of FIG. 1, and FIG. 3 is a schematic view showing a rocker arm adjusting mechanism as a conventional example. In the figure, 1 is a rocker arm, 5 is an adjusting screw,
Reference numeral 8 is a cap, 11 is an insert member, 15 is a cap body, and 16 is a sheet member.

Claims (1)

[Scope of utility model registration request] 1. A spherical head for swingably fitting a cap in contact with the rear end of a valve rod is formed at the tip of an adjusting screw of a rocker arm, and the head is provided between the head and a smooth inner bottom of the cap. An adjusting mechanism for a rocker arm, characterized in that a surface contacting with a spherical head is smooth, and a cap-shaped seat member having a curved surface rolling on the inner bottom is provided.