JPH07197802A - Timing chain lubricating device of engine - Google Patents

Abstract

PURPOSE:To improve the durability of an idller sprocket and a timing chain of a valve driving system, and to reduce the noise. CONSTITUTION:In an engine where a timing chain is stretched between a crank sprocket provided on a crankshaft, a cam sprocket provided on a cam shaft, and an idller sprocket, and a chain guide 30 to prevent the swaying is provided on the side of this timing chain, a rib 32 is formed on the ceiling part of the chain guide 30, and a flow passage 34 of the lubricating oil is formed between this rib 32 and a chain cover 33 to cover the whole timing chain. This constitution enables the lubrication oil splashed by the timing chain to flow in this flow passage 34, and the oil is guided into a meshing part of the idler sprocket with the timing chain 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timing chain lubrication device for an engine in which a chain guide of a timing chain used in a valve drive system has lubricity.

[0002]

2. Description of the Related Art The structure of an engine valve drive system will be described with reference to FIG. In the figure, two cylinder heads, namely, a right cylinder head 3 and a left cylinder head 4 are provided above the cylinder block 2 of the engine 1.
Are provided, and cylinder head covers 5 and 6 are attached to the upper portions of the cylinder heads 3 and 4, respectively.

A crankshaft 7 is rotatably provided on the cylinder block 2, and a crank sprocket 8 is fixed to an end of the crankshaft 7. The crank sprocket 8 drives the idler sprocket 10 provided on the right cylinder head 3 and the cam sprocket 12 provided on the cam shaft 11 of the left cylinder head 4 by the timing chain 9. The rotation is right rotation.

A small diameter idler sprocket is provided above the crank sprocket 8 of the crankshaft 7 and between the idler sprocket 10 and the cam sprocket 12.
13 is rotatably provided.

The idler sprocket 10 of the right cylinder head 3 drives the cam sprockets 15 and 16 by the cam chain 14, and the cam sprocket 12 of the left cylinder head 4 drives the cam sprockets 18 and 19 by the cam chain 17. It is driving.

The tensioner 20 and the adjuster 21 constantly apply a constant tension to the timing chain 9, and the chain guide 22 and the cylinder head 4 on the left side.
The chain guide 23 prevents the swinging.

A chain jet 24 is provided above the crank sprocket 8 to eject the lubricating oil pumped from the engine 1 toward the meshing portion between the crank sprocket 8 and the timing chain 9.

This is to prevent the generation of noise by suppressing the wear of the engaging portion between the crank sprocket 8 and the timing chain 9. Arrow A indicates the direction of jetting of lubricating oil.

In FIG. 4, the idler sprocket 10, the cam sprocket 12, the idler sprocket 13 and the crank sprocket 8 provided in the middle of the cylinder block 2, the timing chain 9 engaged with these sprockets, and the like have a chain cover on the outside. (Not shown)
Is installed.

An oil pan 25 is provided below the cylinder block 2. Inside the oil pan 25, an oil pump 26 for pumping lubricating oil to each part of the engine 1 is provided.
Is provided.

A chain 28 is engaged with the oil pump sprocket 27 of the oil pump 26 and the crank sprocket 8 of the crankshaft 7, and the crankshaft 7 has this chain.
The oil pump 26 is rotating via 28.

As a lubricating device for the cam chain guide, there is one disclosed in Japanese Patent Laid-Open No. 4-159408. What is disclosed in this publication is that a cylinder block is provided with an oil hole for communicating a chain guide of a chain engaged with a cam shaft and a crank shaft with a cam chamber.

As a chain guide lubricating device, there is one disclosed in Japanese Utility Model Publication No. 64-3764. What is disclosed in this publication is that a chain guide having two grooves is arranged along the chain so that oil is supplied to the chain from above.

As a lubricating device for a timing chain, there is one disclosed in Japanese Utility Model Laid-Open No. 63-40510. In the one disclosed in this publication, a guide is arranged so that the oil returned from the cylinder head side to the oil pan side is directly guided to the sliding contact portion of the guide stopper for preventing the shake of the timing chain. It was set up.

Further, as a lubrication device, a guide part is provided to supply oil to the engagement part of the chain and the sprocket (Japanese Utility Model Laid-Open No. 60-159810), and a saucer-shaped protrusion is provided at the bottom of the crank sprocket Tamono (Shinkai Sho 63-1
74513), an oil guide protrusion provided on the back side of the chain cover inserted into a hollow part provided at the shaft end of the idler sprocket (Actual Publication No. 3-47408), and
As an oil supply device, there is a device that collects oil and supplies it to the biting portion (Japanese Utility Model Laid-Open No. 1-166708).

[0016]

In the prior art described above, both the crank sprocket and the idler sprocket with which the timing chain engages have a small diameter in order to make the entire drive system compact and reduce weight. Since the driving load is large, the chain and the sprocket are easily worn, and when worn, the noise due to the biting noise becomes large.

Therefore, although a chain jet is provided above the crank sprocket to eject the lubricating oil to the engaging portion between the crank sprocket and the timing chain, the chain jet is provided at the engaging portion between the idler sprocket and the chain. Since the space could not be taken, the same problem as above occurred. Further, even if the chain jet is provided, it is necessary to provide a passage for supplying lubricating oil from the engine, which may lead to problems such as a complicated lubrication path, an increase in the number of parts and an increase in weight.

In the lubrication device for a cam chain guide disclosed in Japanese Patent Laid-Open No. 4-159408, an oil hole communicating with the cam chamber is provided in the chain guide, but an oil hole is formed in the cylinder block. Therefore, the structure may be complicated.

The lubrication device for a chain guide disclosed in Japanese Utility Model Publication No. 64-3764 is designed to supply oil to the chain from the upper part of the chain guide along the chain. There is a problem in that the cam sprocket and the chain are supplied to the downstream side of the biting portion.

Further, since the timing chain lubrication device disclosed in Japanese Utility Model Laid-Open No. 63-40510 has a guide provided on a guide stopper which has been conventionally provided, a member corresponding to the guide is required. There is a problem.

In addition, Japanese Utility Model Publication No. 60-159810 and Japanese Utility Model Publication 63.
The structure of the lubrication device of Japanese Utility Model Publication No. 174513 and Japanese Utility Model Publication No. 3-47408 and the oil supply device of Japanese Utility Model Application Publication No. 1-166708 are more complicated than those of the present invention.

The present invention has been made in order to solve the above-mentioned conventional problems. In the conventional space, lubricating oil is supplied to the engagement portion between the idler sprocket and the timing chain so that the idler sprocket and the timing chain are connected to each other. An object of the present invention is to provide a lubrication device for a timing chain that has improved durability and reduced noise.

[0023]

As a means for solving the above problems, the present invention engages a timing chain on a crank sprocket provided on a crankshaft, a cam sprocket and an idler sprocket provided on a camshaft, and the timing chain is engaged. In an engine in which a swing-preventing chain guide is provided on a side portion of a chain, a rib is formed on a ceiling portion of the chain guide, and a flow passage of lubricating oil is formed between the rib and a chain cover that covers the entire timing chain. It is characterized by being formed.

Further, the present invention is characterized in that the rib formed on the ceiling portion of the chain guide is extended to the engaging portion between the idler sprocket and the timing chain.

[0025]

As described above, according to the present invention, since the lubricating oil flow passage is formed between the rib formed on the ceiling portion of the chain guide and the chain cover covering the entire timing chain, the lubricating oil splashed by the timing chain is formed. Allows the flow passage to flow along the timing chain.

Further, since the rib provided on the chain guide is extended to the engaging portion between the idler sprocket and the timing chain, the flow passage formed by the rib and the chain cover is extended to the engaging portion. Therefore, it becomes possible to guide the lubricating oil splashed by the timing chain to the biting part.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, the outline of the main part of this embodiment will be described with reference to FIG. FIG. 3 shows a portion of the left cylinder head 4 provided above the cylinder block 2 of the engine 1 (see FIG. 4). A cylinder head cover 6 is provided above the left cylinder head 4.

A cam sprocket 12 attached to a cam shaft 11 is provided on the upper part of the left cylinder head 4, and a cylinder block intermediate between the left cylinder head 4 and the right cylinder head 3 (see FIG. 4). A small diameter idler sprocket 13 is rotatably provided on the second portion by a bolt 29.

The cam sprocket 12, the small diameter idler sprocket 13, the idler sprocket 10 (see FIG. 4) and the crankshaft 7 of the right cylinder head 3.
A timing chain 9 is hung on the crank sprocket 8 (see FIG. 4), and the crankshaft 7 drives the cam sprocket 12 and the small-diameter idler sprocket 13 via the timing chain 9.

As a result, a small diameter idler sprocket 13
Rotates counterclockwise as indicated by arrow B, and the timing chain 9 is pulled toward the idler sprocket 13 side. Further, the cam sprocket 12 drives two cam sprockets 18 and 19 by a cam chain 17.

A chain guide 30 for preventing the timing chain 9 from swinging is provided on the side of the timing chain 9.
Is provided. The chain guide 30 is fixed to the left cylinder head 4 with bolts 31. The chain guide 30 is provided from the vicinity of the cam sprocket 12 to the vicinity of the small diameter idler sprocket 13.

The cross section of the chain guide 30 is U-shaped as shown in FIG. 1, and a rib 32 parallel to the surface of the left cylinder head 4 is provided on the ceiling of the chain guide 30 so as to project therefrom. There is.

The rib 32 is provided over the entire length of the chain guide 30. That is, from the end 30a of the chain guide 30 on the cam sprocket 12 side to the idler sprocket 13
It is formed up to the side end 30b.

The entire timing chain 9 of the engine 1 is covered with a chain cover 33 (see FIG. 1). When the outside of the chain guide 30 is covered with the chain cover 33 in this way, the rib 32 and the wall portion of the chain cover 33 are covered.
A space is formed with 33a. This space serves as a lubricating oil flow passage 34.

In this embodiment, as described above, the ribs 32 formed on the ceiling of the chain guide 30 and the wall portion 33 of the chain cover 33 that covers the entire timing chain 9 of the engine 1 are used.
A space is formed between a and the flow passage of the lubricating oil in this space.
Since 34 is formed, the lubricating oil splashed by the timing chain 9 flows through the flow passage 34 in the timing chain 9
Will flow along.

Since the flow passage 34 formed by the rib 32 and the chain cover 33 is extended to the engaging portion of the small diameter idler sprocket 13 and the timing chain 9, the lubricating oil splashed by the timing chain 9 is The flow passage 34 can be guided to the biting portion. As a result, the bite portion can be lubricated.

[0037]

Since the present invention is a timing chain lubricating device for an engine configured as described above, wear of the meshing portions of the idler sprocket and the timing chain is reduced and durability is improved. Therefore, the biting noise is reduced and the noise is reduced.

Further, since the present invention can be realized only by forming the ribs on the chain guide, it can be carried out in the conventional space and can be carried out with the conventional number of parts.
The problem of weight increase can also be avoided.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, which is taken along line CC of FIG.
It is sectional drawing which follows the line.

FIG. 2 is a sectional view taken along the line DD of FIG.

FIG. 3 is a view showing a mounting portion of a timing chain lubricating device for an engine according to the present invention.

FIG. 4 is a front view showing a valve operating system by a conventional timing chain.

[Explanation of symbols]

 1 engine 7 crankshaft 8 crank sprocket 9 timing chain 11 camshaft 12 cam sprocket 13 idler sprocket 30 chain guide 32 rib 33 chain cover 34 flow passage

Claims (2)

[Claims] 1. An engine in which a timing chain is engaged with a crank sprocket provided on a crankshaft, a cam sprocket and an idler sprocket provided on a camshaft, and a swing guide chain guide is provided on a side portion of the timing chain, A timing chain lubricating device for an engine, characterized in that a rib is formed on a ceiling portion of the chain guide, and a lubricating oil flow passage is formed between the rib and a chain cover that covers the entire timing chain. 2. A timing chain lubricating device for an engine according to claim 1, wherein a rib formed on a ceiling portion of the chain guide is extended to a biting portion between the idler sprocket and the timing chain.