JPH0811933B2 - Valve train of internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a valve mechanism for an internal combustion engine in which lubricity of an engaging portion between a push rod and a valve lifter is improved.

[Prior art]

The valve mechanism of an internal combustion engine is a so-called push rod type in which a rocker arm above the cylinder head is swung by a cam shaft arranged in a crank chamber via a valve lifter and a push rod to drive intake and exhaust valves. There is.

In such a push rod type valve operating mechanism, there is a problem that a portion where the valve lifter and the push rod engage with each other is easily worn due to friction between metals. Conventionally, normal lubrication of this engaging portion has been performed mainly by adhering the fog-drop oil generated when the stored oil in the crank chamber is scraped up by the scraper of the crankshaft, but this is not always sufficient. I couldn't say.

Also, in the case where the oil ejected from the oil passage in the rocker arm is allowed to naturally flow into the cylinder block from the drop hole in the lower part of the cylinder head, weirs are projected on both sides of the drop hole so that a part of the oil flows through the rocker arm. Some internal combustion engines are designed to shunt to the engaging portion of the swinging push rod and valve lifter, but in the past, this type of engine was designed to reduce the amount of oil flowing down immediately after the start of the engine, which tends to run short of oil. It is not possible to supply the entire amount to the engagement part, and because the distribution ratio of the oil supplied to the intake valve side and the exhaust valve side cannot be set appropriately,
There is a problem that it is not possible to supply an appropriate amount of oil to each of the intake valve side and the exhaust valve side.

[Object of the Invention]

An object of the present invention is to improve the lubrication of the engaging portion between the push rod and the valve lifter in the push rod type valve mechanism even immediately after the start of the engine, and further, to improve the intake valve. The present invention relates to a valve operating mechanism of an internal combustion engine capable of arbitrarily setting an oil distribution ratio between a side pushing rod and an exhaust valve side pushing rod.

[Structure of Invention]

According to the present invention to achieve the above object, a rocker arm above a cylinder head is swung by a cam shaft arranged in a crank chamber via a pair of valve lifters and a push rod that are arranged in parallel in the crank shaft direction to suck and exhaust air. In an internal combustion engine that has a push rod type valve operating mechanism that drives a valve and is configured to guide the mist droplet oil in the crank chamber from the crank chamber to the upper part of the cylinder head, the axial direction of the cylinder is inclined around the crankshaft. In addition, a common single in-cylinder passage, through which both push rods penetrate to the upper part of the cylinder head, is formed along the lower side wall of the inclined cylinder, and the intake rod is provided on the inner wall surface on the push rod lower side of the in-cylinder passage. It is installed between the valve-side push rod and the exhaust valve-side push rod, and the upper part serves as a flow dividing part and the lower part extends near the engaging part between the valve lifter and the push rod. In which characterized in that a weir of appropriate height with the exhaust valve-side inclined surface and the intake valve inclined surface.

〔Example〕

 Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings.

The figure shows an engine provided with a valve mechanism according to the present invention.

In the figure, 1 is a cylinder, 2 is a cylinder head, 3
Is the crankcase. A piston 4 is fitted in the cylinder 1, and the piston 4 is adapted to drive a crankshaft 6 to rotate via a connecting rod 5. Cylinder head 2
A combustion chamber 7 is formed at the upper end of the cylinder 1.

A space 9 surrounded by the cylinder head cover 8 is formed in the upper portion of the cylinder head 2, and a rocker arm 11 for driving an exhaust valve 10 is provided therein.
The rocker arm 11 has one end in contact with the upper end of the valve shaft of the exhaust valve 10 and the other end in engagement with the upper end of the push rod 12. The push rod 12 extends downward in a passage 15 provided so as to extend the side portion of the cylinder 1 from the space 9 to the crank chamber 3a side, and a lower end of the push rod 12 is supported by a valve lifter 13 slidably supported. Engaged. The valve lifter 13 has a lower end protruding into the crank chamber 3a and is in contact with the cam shaft 14. Such a push rod type valve operating mechanism is also provided on the intake valve side as shown in FIG. 2 in which the push rod 12 'and the valve lifter 13' are partially illustrated.

On the other hand, oil O is stored in the crank chamber 3a in the crankcase 3. This oil O attaches the droplets, which are scraped up by the scraper 6a attached to the crankshaft 6, to the places where lubrication is required, and partly becomes fine mist-drop oil and floats. This oil in the form of mist is pressurized when the piston 4 descends in the explosive stroke or the intake stroke, is pushed into the passage 16, is forcibly sent to the upper space 9, and adheres to the rocker arm 11 of the valve mechanism. Then
It is designed to lubricate them. The fog-dropped oil sent to the space 9 then flows down in the form of a film on the wall surface of the passage 15, and then flows back into the crank chamber 3a through the lower through hole 17 (see FIG. 2).

A weir 18 is provided on the inner wall surface of the passage 15 through which the push rods 12, 12 'pass, and the upper edge of the weir 18 is a mountain-shaped inclined surface 18a, 18a.
formed in b. Therefore, a part of the oil flowing down from the upper space 9 of the cylinder head 2 along the inner wall surface of the passage 15 is divided into the left and right by the inclined surfaces 18a, 18b, and the push rods 12, 12 'and the valve lifter 13, 13 'engaging part 19,1
It is forced to flow toward 9 '. This oil is used in the engagement part 1 where the two members are in metal contact with each other.
The lubrication is 9,19 'to compensate for the lack of lubrication that was conventionally done only by depositing oil in the form of mist. The oil abundantly supplied to the engaging portions 19 and 19 'also serves to buffer the collision between the metals.

In the above embodiment, the inclined surface 18a has a gentler inclination than the inclined surface 18b, thereby increasing the amount of oil flowing to the engaging portion 19 on the exhaust valve 10 side. This can be arbitrarily changed according to the required characteristics of the engine, and the inclination may be changed so as to flow more to the opposite intake valve side engaging portion 19 ', or both engaging portions 19 and 19'.
The slopes may be equal so that they flow evenly.

〔The invention's effect〕

As described above, according to the present invention, the intake / exhaust valve is rocked by the rocker arm above the cylinder head by the cam shaft arranged in the crank chamber via the pair of valve lifters and the push rod that are arranged in parallel in the crank axis direction. In an internal combustion engine having a push rod type valve operating mechanism for driving the cylinder, and configured to guide the mist droplet oil in the crank chamber from the crank chamber to the upper part of the cylinder head, the axial direction of the cylinder is inclined around the crankshaft. In addition, a common single cylinder passage through which both push rods penetrate to the upper part of the cylinder head is formed along the lower side wall portion of the inclined cylinder, and an intake valve is provided on the inner wall surface of the cylinder passage on the lower side of the push rod. It is installed between the side push rod and the exhaust valve side push rod, and the upper part serves as a flow dividing part and the lower part extends to the vicinity of the engaging part between the valve lifter and the push rod. Since the weir having an appropriate height having the valve inclined surface and the exhaust valve side inclined surface is provided, the oil flowing down the inner wall surface of the passage is forced to flow to the engaging portion between the push rod and the valve lifter by the inclined surface of the weir. Therefore, the conventional lack of lubrication can be supplemented.

In addition, especially immediately after the start of the engine, sufficient oil is not yet supplied to the engaging portion between the valve lifter and the push rod, and a small amount of mist adhering to the inner wall surface of the penetration through which the push rod penetrates. It is necessary to supply as much dripping oil to the engaging portion as possible, but according to the present invention, the cylinder axial direction is tilted around the crankshaft, and both push rods pass through a common single head. Through the passage in the cylinder
Formed along the lower side wall of the inclined cylinder,
Since the weir is provided on the inner wall surface on the lower side of the push rod of the in-cylinder passage, a small amount of fog droplet oil adhering to the inner wall surface of the passage is collected on the inner wall surface on the lower side of the push rod to engage the entire amount. Therefore, it is possible to supply sufficient oil immediately after the start of the engine that tends to run short of oil.

Further, since the weir is provided on the inner wall surface on the lower side of the push rod between the push rod on the intake valve side and the push rod on the exhaust valve side, even if the height of the weir is increased, the weir does not interfere with the push rod and The degree of freedom in height design can be increased.

In addition, a weir of appropriate height having an intake valve-side inclined surface and an exhaust valve-side inclined surface whose upper portion serves as a flow-dividing portion and whose lower portion extends to the vicinity of the engaging portion between the valve lifter and the push rod is installed on the intake valve-side pushing surface. Since it is arranged between the rod and the push valve on the exhaust valve side, it is possible to increase or decrease the oil supply amount on either the intake or exhaust valve side simply by setting the flow dividing positions on both inclined surfaces appropriately. Since it can be easily set, the distribution ratio of oil to the intake valve side and the exhaust valve side can be set arbitrarily.

In addition, since it is configured to guide the fog-drop oil in the crank chamber from the crank chamber to the upper part of the cylinder head, it is difficult for sufficient oil to flow to the passage through which the push rod penetrates, especially immediately after the engine is started. The axial direction of is inclined about the crankshaft so that the oil is collected on the inner wall surface of the lower side of the push rod of the passage through which the push rod penetrates to the upper part of the cylinder head, and the weir is provided at that portion.
Can collect and supply enough oil.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an engine provided with a valve operating mechanism of the present invention, and FIG. 2 is a view taken along the line II-II of FIG. 1 ... Cylinder, 2 ... Cylinder head, 3 ... Crank case, 3a ... Crank chamber, 9 ... Space, 10 ... Exhaust valve, 11 ... Rocker arm, 12, 12 '... Push rod, 13, 1
3 '... Valve lifter, 14 ... Cam shaft, 15,16 ... Passage, 18 ...
… Weir, 18a, 18b …… Sloping surface, 19,19 ′ …… Engagement part.

Claims (1)

[Claims] 1. A suction / exhaust valve is driven by rocking a rocker arm above a cylinder head via a pair of valve lifters and a push rod arranged in parallel in the crankshaft direction by a cam shaft arranged in a crank chamber. In an internal combustion engine having a push rod type valve operating mechanism, configured to guide the mist droplet oil in the crank chamber from the crank chamber to the upper part of the cylinder head,
The cylinder axial direction is inclined around the crank axis, and a common single cylinder passage through which both push rods penetrate to the upper part of the cylinder head is formed along the inclined lower wall portion of the cylinder. Is disposed between the intake valve side push rod and the exhaust valve side push rod on the inner wall surface of the push rod lower side of
A valve mechanism for an internal combustion engine, characterized in that a weir of an appropriate height having an inclined surface on the intake valve side and an inclined surface on the exhaust valve side, the lower part of which extends to the vicinity of the engaging portion between the valve lifter and the push rod, is provided. .