JPS6121527Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve train for an internal combustion engine.

The rocker arm and cam in an overhead cam type engine are usually engaged with each other by welding a butt to the rocker arm and bringing the cam and pad into sliding contact. However, when this type of rocker arm is used, the cam and pads are subject to severe wear, resulting in problems with durability and reliability.

This problem is due to the fact that the contact between the conventional cam and the rocker arm is a sliding contact.To avoid this problem, a roller is attached to the rocker arm and the contact is changed from the conventional sliding contact to a rolling contact. It is considered effective to change to In this case, it is important to lubricate the rolling contact surface between the roller and the cam, but it is also important to lubricate the sliding contact surface between the roller and the shaft that supports it. One key point in realizing a roller-type rocker arm is whether or not it can be carried out smoothly.

The present invention is designed to ensure good lubrication of the contact surface when the cam and rocker arm are in rolling contact, especially the sliding contact surface between the roller and its support shaft when a roller is used. The purpose of the present invention is to provide a roller-type rocker arm.

The roller-type rocker arm of the present invention, which meets this purpose, supports the roller attached to the rocker arm with a hollow pin, and this hollow pin is provided with radial oil holes to remove oil mist that has entered the inside of the hollow pin. Oil is introduced to the contact portion between the roller and the hollow pin to lubricate the contact portion.

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

1 to 3 show a valve train according to this embodiment. In the figures, 1 is a cam, 2 is a rocker arm that swings around a rocker shaft 3, and 4 is an intake valve or an exhaust valve.

The end of the Rotsuker arm 2 on the cam 1 side is formed into forks 5, 5, and a roller 6 is inserted between the forks 5, 5, and the roller 6 is inserted around the hollow pin 7 passed between the forks 5, 5. It is rotatably supported. The hollow pin 7 extends to the outer surface of the forks 5, 5, and the hollow part 8 inside the hollow pin 7 is
Both ends of the hollow pin 7 are open and communicated with the atmosphere.

The hollow pin 7 itself is fixed to the rocker arm 2. The outer peripheral surface of the hollow pin 7 slides on the roller 6, and the sliding portion 9 and the hollow portion 8 are communicated with each other through an oil hole 10 provided in the roller 6 and extending in the radial direction. Although the illustrated example shows a case where two oil holes 10 are provided, the number of oil holes 10 is not limited to two.

On the other hand, the rocker shaft 3 itself is also hollow, and oil holes 11 are also provided in the wall of the rocker shaft 3. A separate oil hole 12 is provided in the rocker arm 2 from the outer peripheral surface of the rocker shaft 3 to a position facing the roller 6, and as the rocker arm 2 swings, the oil hole 11 and the oil hole 12 match.
They are starting to move away from each other.

Lubrication in the roller type rocker arm having the above configuration is achieved as follows.

That is, first, the sliding part 9 between the hollow pin 7 and the roller 6 is exposed to the atmosphere of oil mist around the rocker arm 2 during engine operation.
The mist enters the hollow part 8 and reaches the sliding part 9 through an oil hole 10 extending in the radial direction, and is well lubricated by the oil contained in this mist.

In addition, when the oil hole 11 and the oil hole 12 are aligned with each other as the rocker arm 2 swings, the rolling contact surface between the cam 1 and the roller 6 is caused by the pressure oil in the hollow part of the rocker shaft 3 gushing out and causing the roller to roll. 6 and roller 6
As the roller 6 rotates, the oil adhering to the surface of the roller 6 reaches the contact surface with the cam 1, and intermittently lubricates the contact portion.

Since the roller-type rocker arm of the present invention has the above-mentioned structure and function, when the roller is attached to the rocker arm, the sliding surface of the roller, especially the sliding surface with the hollow pin, can be smoothed. It can be lubricated, making it possible to use a roller-type rocker arm, and by using a roller-type rocker arm, wear on the cam and rocker arm can be suppressed, greatly improving durability.

[Brief explanation of the drawing]

1 is a front view of a roller type rocker arm and its vicinity according to an embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1, and FIG. 3 is a plan view of FIG. 1. 1...Cam, 2...Rotsuka arm, 3...Rotsuka shaft, 6...Roller, 7...Hollow pin,
8...Hollow part, 9...Sliding part, 10, 11, 12
...Oil hole.

Claims (1)

[Scope of utility model registration request] In the rocker arm of the valve train of an overhead cam engine, the roller that contacts the cam is attached to the rocker arm with a hollow pin, and the contact area between the roller and the hollow pin is coated with oil mist through the hollow part inside the hollow pin. A roller-type rocker arm characterized by forming oil holes extending in the radial direction that communicate with the atmosphere.