JPH05179919A - Valve system - Google Patents

Abstract

PURPOSE:To reduce any wear due to an oil shortage in a pivot part by inducting oil at the side of a camshaft into a pivot support part of a rocker shaft even in time of low engine speed in particular and thereby lubricating the pivot part positively in a sufficient manner. CONSTITUTION:An oil passage 60 extending in the axial direction is installed in a camshaft 32. Likewise, an oil through passage 62 extending in the radial direction to pierce through an external part of the camshaft from this oil passage 60 is also installed. Then, in order to induct oil scattering out of the oil through passage into a pivot support part 48, an oil inlet passage 64 pointing to the camshaft direction as tilting a little in the upper direction from the pivot support part 48 is installed in a rocker arm 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating system, and more particularly to a valve operating system in which a rocker arm swung by a cam of a cam shaft rotated by an engine is supported by a pivot part which engages with a pivot supporting part of the rocker arm. Regarding the device.

[0002]

2. Description of the Related Art An engine, particularly a four-cycle engine, is provided with an intake valve and an exhaust valve in order to intake air into a combustion chamber and exhaust gas from the combustion chamber. These valves include side valve type and overhead valve type.
Some valve operating mechanisms for driving these valves, for example, valve operating mechanisms for overhead valve type valves are provided with a seesaw type or swing type rocker arm in order to transmit the operation of the cam of the cam shaft to the valve. .

The seesaw type rocker arm has an intermediate portion pivotally supported by a rocker shaft, one end of which is slidably contacted by a cam of a cam shaft and the other end of which is abutted by a valve stem.

Further, one end of the swing type rocker arm is pivotally supported by the pivot part, the middle part is slidably contacted with the cam of the cam shaft, and the other end side is contacted with the valve stem.

There is a direct drive type valve operating mechanism for an overhead valve type valve in which a valve stem is directly driven by a cam of a camshaft.

As an overhead valve type valve operating mechanism, as disclosed in Japanese Patent Laid-Open No. 58-88412, an engine provided with an overhead valve type valve operating mechanism and a head cover surrounding the valve operating mechanism is used as a cylinder. In some cases, a portion is formed on a head cover, a rocker arm of a valve mechanism is pivotally supported, and a hydraulic rocker arm support shaft device for automatically adjusting a clearance is inserted into and retracted from a cylinder portion of the head cover.

[0007]

By the way, in the conventional valve gear, there is a rocker arm other than the rocker shaft, for example, a pivot part for supporting the rocker arm in order to reduce the weight of the valve gear.

In such a case, the load on the pivot portion, which is the fulcrum of the rocking motion of the rocker shaft, is larger than that when the rocker shaft is used, so that the pivot portion must be sufficiently lubricated. There is.

However, in the conventional valve train, since the pivot portion is lubricated by the spraying method, the pivot portion cannot be sufficiently lubricated especially at a low engine speed, and seizure wear of the pivot portion occurs. There is a fear of inviting,
Oil deposits will stick around the pivot,
There was an inconvenience that it was a disadvantage in practice.

[0010]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a cam shaft rotated by an engine and a rocker arm swingable by a cam of the cam shaft. In a valve gear supported by a pivot portion that engages with a pivot support portion provided on a rocker arm, an oil passage extending in the axial direction is provided in the camshaft, and a radial direction is provided to penetrate from the oil passage to the outside of the camshaft. An oil introduction passage extending toward the cam shaft is provided in the rocker arm in order to introduce oil splashing from the oil passage into the pivot support portion while being inclined slightly upward from the pivot support portion. It is characterized by being provided.

[0011]

According to the invention as described above, when the camshaft is rotated by driving the engine, the rocker arm is swung by the cam of the camshaft and the oil in the oil passage formed in the camshaft penetrates the oil. Oil is scattered from the road and oil is introduced to the pivot portion from an oil introduction passage provided in the rocker arm.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the present invention. In FIG. 1, 2 is an engine and 4 is a cylinder head. The cylinder head 4 of the engine 2 is provided with a combustion chamber 6 formed by a cylinder block and a piston (not shown), and an intake port 8 and an exhaust port 10 communicating with the combustion chamber 6.

The intake valve stem 20 and the exhaust valve stem 22 of the intake valve 12 and the exhaust valve 14 for opening and closing the intake port 8 and the exhaust port 10 are provided with an intake valve spring 20 and an exhaust valve spring 22, respectively. A contact portion 24 and an exhaust valve stem contact portion 26 are provided respectively.

The valve operating mechanism 30 provided in the valve operating chamber 28 of the cylinder head 4 is provided with a cam shaft 32 rotated by the engine 2 pivotally supported on the cylinder head 4 by a cam cap 34. An intake cam 36 and an exhaust cam 38 provided on the shaft 32 drive a seesaw type intake rocker arm 40 and a swing type exhaust rocker arm 42, respectively.

The intake rocker arm 40 is provided with a first cam contact portion 44 at one end side, a first pivot support portion 48 for engaging a later-described first pivot portion 46 at an intermediate portion, and the other end side. Is provided with a first contact portion 50 that contacts the intake valve stem contact portion 24.

The exhaust rocker arm 42 has a second pivot support portion 52 formed on the cylinder head 4 at one end thereof.
Is provided with a second cam contact portion 56 at an intermediate portion, and a second contact portion 58 contacted with the exhaust valve stem contact portion 26 is provided at the other end side. ing.

The valve operating mechanism 30 of the engine 2 includes an intake cam 36 of a cam shaft 32 rotated by the engine 2.
The intake cam rocker arm 40 and the exhaust rocker arm 42 are driven by the exhaust cam 38 to swing.

Further, the intake rocker arm 40 is swung by the intake cam 36 of the cam shaft 32 about the first pivot portion 46 engaging with the first pivot support portion 52 at the intermediate portion as the swing center, and at the other end side. The first contact portion 50 moves the intake valve stem 16 in the axial direction to open / close the intake valve 12 provided in the intake port 8.

Furthermore, the exhaust rocker arm 42 is swung by the exhaust cam 38 of the cam shaft 32 about the second pivot portion 54 on one end side that engages with the second pivot support portion 56 of the cylinder head 4, The second contact portion 58 on the other end side moves the exhaust valve stem 18 in the axial direction to open / close the exhaust valve 14 provided in the exhaust port 10.

Furthermore, an oil passage 60 extending in the axial direction is provided in the cam shaft 32, and an oil passage 62 extending in the radial direction is provided so as to penetrate from the oil passage 60 to the outside of the cam shaft 32. Intake rocker arm 40 absorbs oil splashing from through passage 62.
In order to introduce the intake rocker arm 40 into the first pivot support portion 48, an oil introduction passage 64 that is directed toward the camshaft 32 while being inclined slightly upward from the first pivot support portion 48 is provided.

More specifically, the camshaft 32 is provided with one oil passage 60 extending in the axial direction of the camshaft 32, and the oil passage 60 extends in the radial direction of the camshaft 32 to extend from the camshaft 32. The same number of oil passages 62 that penetrate the outside as the intake rocker arms 40 are provided.

Further, as shown in FIG. 1, the intake rocker arm 40 penetrates from the first pivot portion 48 formed on the intake rocker arm 40 to the camshaft 32 side (right side in FIG. 1) and gradually moves upward. An oil introduction passage 64 that is inclined to the bottom is provided.

Further, the second pivot support portion 56 that engages with the second pivot portion 54 of the exhaust rocker arm is provided with an oil distribution passage 66 through which the oil supply passage 6 of the cylinder head 4 is provided.
8 has been contacted.

Next, the operation will be described.

The camshaft 32 is driven by the drive of the engine 2.
The intake cam 3 of the camshaft 32 when the
6 rocks the intake rocker arm 40,
The exhaust rocker arm 42 is swung by the exhaust cam 38.

At this time, the oil in the oil passage 60 formed in the camshaft 32 is scattered outward from the oil passage 62 by the rotational force of the camshaft 32,
The scattered oil flows into the oil introduction passage 64 provided in the intake rocker arm 40, and the oil is introduced into the first pivot portion 46 by the inclined oil introduction passage 64.

As a result, the oil on the camshaft 32 side is introduced into the first pivot support portion 52 of the intake rocker shaft 40 to ensure sufficient lubrication of the first pivot portion 46 even when the engine 2 is running at low speed. Can be the first
Wear due to lack of oil in the pivot part 46 can be avoided,
It is practically advantageous.

[0029]

As described in detail above, according to the present invention, the camshaft is provided with the oil passage extending in the axial direction,
An oil passage extending in the radial direction from the oil passage to the outside of the camshaft is provided, and the rocker arm is inclined slightly upward from the pivot support to introduce oil splashing from the oil passage to the pivot support. Since the oil introduction passage oriented in the camshaft direction is provided, the oil on the camshaft side can be introduced to the pivot support part of the rocker shaft to ensure sufficient lubrication of the pivot part, and the oil in the pivot part is insufficient. It is possible to reduce wear, which is practically advantageous. Further, by introducing the oil on the camshaft side to the pivot support portion of the rocker shaft, it is possible to introduce a sufficient amount of oil to the pivot portion even when the engine is running at low speed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a valve operating system showing an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a pivot part.

FIG. 3 is a plan view of a valve train.

FIG. 4 is a schematic sectional view of a rocker arm.

[Explanation of symbols]

 2 engine 4 cylinder head 30 valve mechanism 32 camshaft 40 intake rocker arm 42 exhaust rocker arm 46 first pivot part 48 first pivot support part 52 second pivot support part 54 second pivot 60 oil passage 62 oil through passage 64 oil introduction passage 66 oil distribution passage 68 oil supply passage

Claims (1)

[Claims] 1. A camshaft that is rotated by an engine and a rocker arm that is swung by a cam of the camshaft are provided, and the rocker arm is supported by a pivot portion that engages with a pivot support portion provided on the rocker arm. In the valve gear, an oil passage extending in the axial direction is provided in the camshaft, an oil passage extending in the radial direction is provided so as to penetrate from the oil passage to the outside of the camshaft, and oil scattered from the oil passage is A valve train, wherein the rocker arm is provided with an oil introduction passage that is directed toward the camshaft while being inclined slightly upward from the pivot support portion so as to be introduced into the pivot support portion.