JP2007263023A - Rocker arm for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure lubricity and inhibit wear of a roller and a support shaft by inhibiting drop of rotation speed of the roller at a time of valve closure of an intake valve or an exhaust valve. <P>SOLUTION: The rocker arm for an engine abutting on a cam 4 for driving the intake valve by the roller 8, and is constructed with including a main body of the rocker arm and the support shaft 7 provided on the main body and having the roller 8 loosely fitted on an outer circumference thereof with a gap 22. The support shaft7 is provided with a first hole 32 forming an opening 24 communicating to the gap 22 for introducing lubrication oil to the gap 22. The first hole 32 is formed with a center axis Lc thereof crossing with a radial direction Dr of the support shaft 7 in a section perpendicular to the support shaft 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine rocker arm, and more particularly to a rocker arm that abuts a cam for driving an intake valve or an exhaust valve with a roller.

2. Description of the Related Art As a rocker arm that transmits power from a cam to an intake valve or an exhaust valve, there is known a rocker arm that has a roller at a portion that contacts the cam. (Patent Document 1) In this, the roller is loosely fitted to a support shaft fixed to the main body of the rocker arm with a gap, and is supported rotatably with respect to the main body by this support shaft. Further, a thin tube for introducing lubricating oil into the gap between the roller and the support shaft is formed on the support shaft in order to reduce friction with the roller.
Japanese Patent Application Laid-Open No. 08-093418 (paragraph number 0005)

In such a rocker arm, the thin tube is extended in the radial direction from the center of the support shaft toward the outer peripheral surface, and the opening of the thin tube is formed on the outer peripheral surface, so that the lubricating oil is supplied from the opening to the gap. Thus, the lubricating oil can be supplied to the entire outer peripheral surface of the support shaft so as to be involved in the rotation of the roller.
However, in this case, since the narrow tube extends in the radial direction, the lubricating oil flows so as to be orthogonal to the flow of the lubricating oil in the gap, so that the flow of the lubricating oil in the gap is obstructed by replenishment. Will be.

  Here, in an engine provided with a rocker arm, a clearance is generally set between a cam and a roller in order to form a valve clearance. In this case, the cam and the roller come into contact with each other when the intake valve or the exhaust valve is opened. On the other hand, when the valve is closed, the cam and the roller are separated from each other, and the rotational driving force is not transmitted from the cam to the roller. Under such circumstances, if the flow of the lubricating oil in the gap is obstructed by replenishing the lubricating oil from the opening, the reduction in the rotation speed of the roller is promoted, and the lubricating oil is applied to the entire outer peripheral surface of the support shaft. Therefore, there is a risk that the lubricity is impaired and the roller and the support shaft are worn by friction.

  Accordingly, an object of the present invention is to ensure lubricity and suppress wear of the roller and the support shaft by suppressing a decrease in the rotation speed of the roller when the intake valve or the exhaust valve is closed. .

  For this reason, the invention according to claim 1 is an engine rocker arm that abuts with a roller to a cam for driving an intake valve or an exhaust valve, and is provided on the body of the rocker arm and the body, and is provided on the outer periphery of the rocker arm. And a support shaft that is loosely fitted with a gap, and the support shaft has a first introduction path that forms an opening communicating with the gap for introducing the lubricating oil into the gap. The first introduction path is formed such that the central axis intersects the radial direction of the support shaft in a cross section perpendicular to the support shaft.

The invention according to claim 2 is characterized in that the opening is formed in the upper part of the support shaft.
In the invention according to claim 3, the rocker arm body is supported by the rocker shaft with respect to the engine, the rocker shaft is provided with a flow passage through which the lubricating oil flows, and the rocker arm body has a first introduction path. And a second introduction path communicating with the flow passage.

  According to the first aspect of the present invention, since the central axis of the first introduction path intersects the radial direction of the support shaft, the lubricating oil is allowed to flow smoothly along the flow of the lubricating oil in the gap, Lubricating oil is smoothly supplied without obstructing the flow of the lubricating oil in the gap. Therefore, since the decrease in the rotation speed of the roller when the intake valve or the exhaust valve is closed is suppressed, the lubricating oil is sufficiently supplied to the entire outer peripheral surface of the support shaft to ensure lubricity, and the roller and the support shaft Abrasion can be suppressed.

According to the second aspect of the invention, since the lubricating oil is supplied to the gap at the upper part of the support shaft, the lubricating oil moves downward in the gap along the support shaft. Therefore, the supply of the lubricating oil to the entire outer peripheral surface of the support shaft can be promoted.
According to invention of Claim 3, lubricating oil can be supplied to the 1st introduction path from the flow path provided in the rocker shaft.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a structural diagram of an engine 2 that employs a rocker arm 1 according to an embodiment of the present invention.
A rocker arm 1 according to this embodiment is driven by a cam 4 provided on a camshaft 3 to open and close an intake valve 5 of an engine 2. The rocker arm 1 includes a main body portion 6, a main body portion, 6 includes a columnar support shaft 7 fixed to one end 6 a of the cylinder 6 and a cylindrical roller 8.

  A rocker shaft 10 is fixed to the cylinder head 9 of the engine 2, and the main body 6 is supported by the rocker shaft 10 so as to be swingable in the vertical direction at the center thereof. The rocker arm 1 contacts the cam 4 with a roller 8 at one end 6a. The other end 6 b of the main body 6 abuts on the upper end of the intake valve 5. In the present embodiment, the shaft portion upper end 5 a of the intake valve 5 is connected by the member 11, and the two intake valves 5 are driven by the single rocker arm 1. Furthermore, in this embodiment, a clearance is provided between the cam 4 and the roller 8 as a valve clearance. The cam 4 and the roller 8 are in contact with each other when the intake valve 5 is opened, but are separated when the valve is closed. To do.

FIG. 2 is a structural diagram of the rocker arm 1 of the present embodiment.
One end 6a of the main body 6 branches into a bifurcated shape, and a shaft support hole 21 is coaxially formed in the branched portion. The end portions 7 a of the support shaft 7 are respectively inserted into the shaft support holes 21, and the support shaft 7 is fixed to the main body portion 6. A roller 8 is loosely fitted to the support shaft 7 in a freely rotatable manner, and a gap 22 is formed between the roller 8 and the support shaft 7.

  Inside the support shaft 7, an introduction path 23 for introducing the lubricating oil of the engine 2 into the gap 22 is formed. The introduction path 23 opens at the upper portion of the outer peripheral surface of the support shaft 7 facing the gap 22 in the opening 24. Further, the introduction path 23 opens at one end 7 a of the support shaft 7 at the opening 25. The rocker shaft 10 is formed with a flow passage 27 for the lubricating oil of the engine 4 along the axis thereof, and the opening 25 is distributed through the body portion introduction passage 26 formed in the body portion 6. It communicates with the road 27. The introduction path 23 that connects the opening 25 and the opening 24 corresponds to the first introduction path of the present invention. The main body introduction path 26 corresponds to a second introduction path of the present invention.

FIG. 3 is a cross-sectional view of the roller 8 and the support shaft 7.
The introduction path 23 has a first hole 31 extending in the axial direction inside the support shaft 7 and a second hole 32 extending in the cross section of the support shaft 7. The first hole 31 communicates with the opening 25 at one end thereof. The second hole 32 communicates the other end of the first hole 31 with the opening 24, and its axis Lc intersects with the radial direction Dr of the support shaft 7. The roller 8 is inclined in the rotation direction Dt. In other words, the second hole 32 is formed such that the axis Lc intersects the radial direction Dr, and on this line, the rotation direction Dt side of the roller 8 extends from the intersection position P as a boundary, and the opening 24 is formed. And is connected to the gap 22.

  With the configuration described above, lubricating oil is supplied from the flow passage 27 to the introduction passage 23 via the main body introduction passage 26. The lubricating oil supplied to the introduction path 23 is introduced from the opening 24 into the gap 22 between the roller 8 and the support shaft 7. Since the second hole 32 is inclined in the rotational direction Dt of the roller 8 with respect to the radial direction Dr of the support shaft 7 and connected to the gap 22, the lubricating oil is introduced into the gap 22 in the inclined direction. The As a result, the lubricating oil smoothly flows along the flow of the lubricating oil in the gap 22 and is smoothly replenished without obstructing the flow of the lubricating oil in the gap. Accordingly, when the intake valve 5 is closed, the flow of the lubricating oil in the gap 22 is maintained, and a decrease in the rotation speed of the roller is suppressed, so that the lubricating oil spreads over the entire outer peripheral surface of the support shaft 7 and lubrication is performed. Sex is secured. Thereby, abrasion of the roller 8 and the support shaft 7 can be suppressed.

Further, since the opening 24 of the first hole 31 is formed at the upper part of the support shaft 7, the lubricating oil is supplied to the gap 22 at the upper part of the support shaft 7. It moves downward in the gap 22 along the outer peripheral surface. Therefore, the supply of the lubricating oil to the entire outer peripheral surface of the support shaft 7 can be promoted.
The second hole 32 may be provided on the side opposite to the cam 4 with the center of the support shaft 7 as a boundary. Thereby, when the cam 4 and the roller 8 contact | abut at the time of valve opening of the intake valve 5, the support shaft 7 can be made to contact with an inner surface with respect to the roller 8, and can be lubricated favorably.

In the present embodiment, one opening 24 is provided for one support shaft 7. However, a plurality of openings 24 may be formed side by side in the axial direction of the support shaft 7, or the circumference of the support shaft 7 may be formed. A plurality may be formed side by side in the direction.
Further, the present invention may be adopted in a rocker arm that drives the exhaust valve of the engine 2.

Structural diagram of an engine according to an embodiment of the present invention Structure diagram of rocker arm according to an embodiment of the present invention Cross section of roller and support shaft

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rocker arm 2 Engine 3 Cam shaft 4 Cam 6 Main part 7 Support shaft 8 Roller 22 Gap 23 Introduction path 26 Main part introduction path 27 Flow path

Claims (3)

An engine rocker arm that abuts with a roller on a cam for driving an intake valve or an exhaust valve,
The body of the rocker arm,
A support shaft provided in the main body and loosely fitted with a gap on the outer periphery, and configured to include,
The support shaft includes a first introduction path that forms an opening communicating with the gap for introducing lubricating oil into the gap;
The first introduction path is an engine rocker arm formed such that a central axis thereof intersects with a radial direction of the support shaft in a cross section perpendicular to the support shaft.   2. The engine rocker arm according to claim 1, wherein the opening is formed in an upper portion of the support shaft. The rocker arm body is supported by the rocker shaft against the engine;
The rocker shaft is provided with a flow passage through which the lubricating oil flows,
3. The engine rocker arm according to claim 1, wherein a second introduction path is provided in the main body of the rocker arm to communicate the first introduction path and the flow path. 4.

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