JPH06264979A - Chain drive device - Google Patents

Abstract

PURPOSE:To simplify a lubricating structure furnished on a chain drive device of an internal combustion engine. CONSTITUTION:In a chain drive device of an internal combustion engine furnished with a first chain 11 and a second chain 12 and to transmit torque of a crankshaft to a camshaft, a sliding surface 25 of a first shoe 24 of a first tensioner device 21 is formed in a curved surface where tangential velocity of the first chain 11 is directed toward a lube oil supply part 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication structure for a chain drive device provided in an internal combustion engine.

[0002]

2. Description of the Related Art In a chain drive system for transmitting a rotational force of a crankshaft of an internal combustion engine to a camshaft on a cylinder head, sufficient lubricating oil is supplied to a shoe or a sprocket of a chain tensioner device. As a result, it is possible to reduce the wear of each part and also reduce the noise generated from the chain (Japanese Patent Laid-Open No. HEI 2-
57750, gazette).

As a conventional chain drive device for an internal combustion engine, there is one shown in FIG. 4, for example.

To explain this, a crank sprocket 1 connected to a crankshaft, a first intake cam sprocket 2 and a second intake cam sprocket 3 connected to an intake camshaft are provided at the front of the internal combustion engine.
Exhaust cam sprocket 4 connected to the exhaust camshaft
And a first chain 11 hung around the crank sprocket 1 and the first intake cam sprocket 2;
Second intake cam sprocket 3 and exhaust cam sprocket 4
It is provided with a second chain 12 which is wound around the crankshaft so as to transmit the rotational force of the crankshaft to each camshaft.

Each sprocket 1, 2, 3, 4 rotates in the direction shown by the arrow in the drawing, and the tension of each chain 11, 12 is adjusted hydraulically on the loose side of the first chain 11 and the second chain 12. First and second chain tensioner device 2
1, 22 are provided respectively.

[0006] As the lubricating oil supply portion that needs to supply the lubricating oil to the first and second chains 11 and 12, the first and second shoes 24 and 23 of the first and second chain tensioner devices 21 and 22 are used. Entry side lubricating oil supply parts 11a, 12a
There are two oil jets 33 and 32 for injecting the lubricating oil toward the respective lubricating oil supply portions 11a and 12a as indicated by arrows in the figure.

[0007]

However, in such a conventional chain drive device for an internal combustion engine, two oil jets 33 and 32 are provided for the first and second shoes 24 and 23, respectively. Therefore, not only the number of parts provided in the chain chamber of the engine increases, but also the structure of the oil passage for guiding the lubricating oil pumped from the oil pump of the engine to the oil jets 33, 32 becomes complicated, and the oil pump There is a problem that it is necessary to increase the capacity of the.

The present invention has been made in view of the above problems, and an object thereof is to simplify a lubricating structure provided in a chain drive system of an internal combustion engine.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a crank sprocket connected to a crankshaft, a first chain wound around the crank sprocket, a cam sprocket connected to the camshaft, and a cam sprocket wound around the cam sprocket. In a chain drive of an internal combustion engine that transmits the rotational force of a crankshaft to a camshaft with a second chain, a chain tensioner device that presses the shoe against one chain is provided, and the slip surface of the shoe is tangential to the chain. Form a curved surface that faces the lubricating oil supply portion of the other chain.

According to a second aspect of the present invention, the first chain tensioner device for pressing the first shoe against the first chain is provided, and the second chain tensioner device for pressing the second shoe against the second chain is provided. The sliding surface is arranged so as to face the crank sprocket, the first chain is circulated so as to face the sliding surface of the second shoe, and the sliding surface of the first shoe has a tangential speed of the first chain that is equal to that of the second chain. It is formed in a curved surface that faces the entry side lubricating oil supply part for the two shoes.

[0011]

[Operation] The chain slides on the sliding surface of the curved shoe,
Lubricating oil scattered from the chain is scattered in the tangential velocity direction of the chain due to its inertial force. By forming the sliding surface of the shoe on the curved surface where the tangential velocity of the chain is directed to the lubricating oil supply part of the other chain, most of the lubricating oil splashed from the chain sliding the shoe lubricates the other chain. The oil supplied to the oil supply unit can reduce the wear of each unit and reduce the noise generated from the chain.

According to the second aspect of the present invention, the lubricating oil scattered from the first chain sliding on the sliding surface of the first shoe is the lubricant of the second chain located in the tangential velocity direction of the first chain due to its inertial force. Towards the approach side lubricating oil supply section for the second shoe. Thereby, the sliding portion of the second chain and the second shoe is lubricated by the lubricating oil that is splashed up from the first chain that slides on the first shoe.

[0013]

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

A crank sprocket 1 connected to a crankshaft, a first intake cam sprocket 2 and a second intake cam sprocket 3 connected to an intake camshaft, and an exhaust camshaft are connected to the front of the internal combustion engine. An exhaust cam sprocket 4 which is wound around a crank sprocket 1 and a first intake cam sprocket 2 and a first chain 11 which is wound around a second intake cam sprocket 3 and an exhaust cam sprocket 4. The two chains 12 are provided, and the rotational force of the crankshaft is transmitted to each camshaft.

Each sprocket 1, 2, 3, 4 rotates in the direction shown by the arrow in the figure, and the first chain 11 and the second chain 12 are provided on the loose side to adjust the tension of each chain 11, 12. A tensioner device 21 and a second chain tensioner device 22 are provided respectively.

The first chain tensioner device 21 includes a first shoe 24 having a sliding surface 25 that is in sliding contact with the first chain 11, and a tubular sleeve 1 to which the first shoe 24 is connected.
7, a body 16 accommodating the sleeve 17, a hydraulic chamber defined between the two, and a spring interposed between the two. The sleeve 17 is pushed out from the body 16 by the hydraulic pressure guided to the hydraulic chamber and the urging force of the spring, and the first shoe 24 is pressed against the first chain 11,
A predetermined tension is applied to the first chain 11.

The second chain tensioner device 22 has a similar structure, and the second shoe 23 is pressed against the second chain 12 to apply a predetermined tension to the second chain 12.

The second chain tensioner device 22 is arranged between the second intake cam sprocket 3 and the exhaust cam sprocket 4 and has a sliding surface 26 on the crank sprocket 1 for slidingly contacting the second chain 12 of the second shoe 23. The sliding surfaces 26 are arranged so as to face each other, and
The cam sprocket 3, 4 is pressed against the loose side located below.

The first chain tensioner device 21 is arranged so that the first shoe 24 is located below the second shoe 23. The first chain 11 sliding on the first shoe 24
Is crank sprocket 1 to first intake sprocket 2
And goes up against the sliding surface 26 of the second shoe 23 to circulate.

As the lubricating oil supply portion that needs to supply the lubricating oil to the first chain 11, there is the entry side lubricating oil supply portion 11a for the first shoe 24, and the lubricating oil is indicated by the arrow in the figure. Is provided with an oil jet 33 that injects toward each lubricating oil supply unit 11a.

As the lubricating oil supply portion that needs to supply the lubricating oil to the second chain 12, there is an entry side lubricating oil supply portion 12a for the second shoe 23.

As the gist of the present invention, the sliding surface 25 of the first shoe 24 is formed into a curved surface whose tangential velocity of the first chain 11 is directed to the lubricating oil supply portion 12a of the second chain 12. Here, the tangential velocity is the instantaneous linear velocity of an object moving on a non-linear trajectory.

In the front view of FIG. 1, the first shoe 24
The sliding surface 25 is formed into a curved surface that is symmetrically curved with respect to the center line O of the sleeve 17. Accordingly, since there is a vector of the tangential velocity of the first chain 11 sliding on the sliding surface 25 on the line segment C that intersects the center line O and the first chain 11 and is orthogonal to the center line O, the line segment C is Second chain 12
Of the lubricating oil supply unit 12a. That is, the shape of the sliding surface 25 of the first shoe 24, which is the track of the first chain 11, has a tangent line (a line segment extending in a direction perpendicular to the radius of the curvature circle) near the lubricating oil supply portion 12a of the second chain 12. To pass through.

Next, the operation will be described.

The first chain 11 is the curved first shoe 2
The lubricating oil that slides on the sliding surface 25 of No. 4 and is scattered from the first chain 11 is scattered in the tangential velocity direction of the first chain by its inertial force. By forming the sliding surface 25 of the first shoe 24 into a curved surface in which the tangential velocity of the first chain 11 is directed to the lubricating oil supply portion 12a of the second chain 12, the sliding surface 25 scatters from the sliding first chain 11. The lubricating oil is directed toward the lubricating oil supply portion 12a of the second chain 12.

The first chain 11 and the second chain 12 are provided offset from each other in the longitudinal direction of the engine,
The lubricating oil scattered from the first chain 12 is the first chain 1
The air flow generated in the chain chamber with the circulation of 1 diffuses and reaches the second chain 11 located behind the first chain 11 in the engine.

As a result, most of the lubricating oil splashed up from the first chain 11 sliding on the sliding surface 25 is supplied to the lubricating oil supply portion 12a of the second chain 12 and the second chain 12 and the second chain tensioner device. The wear of the second shoe 23 of 22 is reduced, and the noise generated from the second chain 12 is reduced.

As a result, the oil jet for injecting the lubricating oil toward the entry side lubricating oil supply portion 12a for the second shoe 23 of the second chain 12 can be eliminated, and the number of parts provided in the chain chamber can be reduced. In addition, the structure of the oil passage for supplying the lubricating oil to the chains 11 and 12 can be simplified and the capacity of the oil pump can be reduced.

Next, another embodiment shown in FIG. 2 will be described.

A crankshaft 9 is provided at the front of the V-type engine.
A first intake cam sprocket 2 and a second intake cam sprocket 3 connected to the intake camshafts of the left and right banks, and an exhaust cam sprocket 4 connected to the exhaust camshaft. The first chain 11 is hung around the crank sprocket 1 and each first intake cam sprocket 2, and the second chain 12 is hung around the second intake cam sprocket 3 and exhaust cam sprocket 4 in the left and right banks, respectively.
And the rotational force of the crankshaft 9 is transmitted to each camshaft.

Each sprocket 1, 2 rotates in the direction shown by the arrow in the figure, and a first chain tensioner device 21 for adjusting the tension of the first chain 11 is provided on the loose side of the first chain 11 located in the right bank. To be In the first chain tensioner device 21, a first shoe 24 having a sliding surface 25 that is in sliding contact with the first chain 11 is rotatably supported by an engine block via a shaft 18. In the figure, 14 is an idler sprocket, and 15, 16 and 17 are chain guides.

The sprocket wheels 3, 4 of the left and right banks rotate in the directions shown by the arrows in the figure, and a second chain tensioner device 22 for adjusting the tension of the second chain 12 is provided on the loose side of the second chain 12.

As a lubricating oil supply portion that needs to be supplied with lubricating oil for the first chain 11, there is an entry side lubricating oil supply portion 11a for the first shoe 24 of the first chain tensioner device 21. The oil jets 3 that inject toward the respective lubricating oil supply parts 11a as indicated by the arrows in the figure.
3 is provided.

As the lubricating oil supply portion of the second chain 12, the second shoe 23 of the second chain tensioner device 22 is used.
There is an entrance side lubricating oil supply part 12a for the.

As shown in FIG. 2, the tangential velocity of the first chain 11 is set on the sliding surface 25 of the first shoe 24 by the second chain 1.
The lubricant oil that is formed on the curved surface facing the second lubricant oil supply portion 12a and is splashed up from the first chain 11 that circulates through the first shoe 24 is indicated by the arrow B in the figure.
2a is reached.

As a result, most of the lubricating oil splashed up from the first chain 11 sliding on the sliding surface 25 is supplied to the lubricating oil supply portion 12a of the second chain 12 and the second chain 12 and the second chain tensioner device. The wear of the second shoe 23 of 22 is reduced, and the noise generated from the second chain 12 is reduced.

[0037]

As described above, according to the present invention, the crank sprocket connected to the crankshaft, the first chain wound around the crank sprocket, the cam sprocket connected to the camshaft, and the cam sprocket. In a chain drive of an internal combustion engine equipped with a rotating second chain to transmit the rotational force of a crankshaft to a camshaft, a chain tensioner device that presses a shoe against one chain is provided, and the sliding surface of the shoe is tangential to the chain. Since the speed is formed on the curved surface that is directed to the lubricating oil supply section of the other chain, most of the lubricating oil that is scattered from the chain is supplied to the lubricating oil supply section of the chain. By reducing the oil passages and simplifying the chain lubrication structure, , It is possible to reduce the capacity of the oil pump.

In the second aspect of the invention, the first chain tensioner device for pressing the first shoe on the first chain and the second chain tensioner device for pressing the second shoe on the second chain are provided, and the second shoe is provided. The first sliding surface of the first shoe is circulated so that the sliding surface of the first shoe faces the sliding surface of the second shoe and the tangential speed of the first shoe is equal to that of the second chain. Since it is formed on the curved surface facing the entry side lubricating oil supply part for the second shoe, the sliding part of the second chain and the second shoe is lubricated by the lubricating oil splashed from the first chain sliding on the first shoe. It

[Brief description of drawings]

FIG. 1 is an overall front view of a chain drive device showing an embodiment of the present invention.

FIG. 2 is an overall front view of a chain drive device showing another embodiment.

FIG. 3 is an enlarged front view of a part of the chain drive device.

FIG. 4 is an overall front view of a chain drive device showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crank sprocket 2 1st intake cam sprocket 3 2nd intake cam sprocket 4 Exhaust cam sprocket 11 1st chain 12 2nd chain 12a Lubricating oil supply part 21 1st chain tensioner device 22 2nd chain tensioner device 23 2nd shoe 24 24th One shoe 25 sliding surface

Claims (2)

[Claims] 1. A crank sprocket connected to a crank shaft, a first chain wound around the crank sprocket, a cam sprocket connected to the cam shaft, and a second chain wound around the cam sprocket. In a chain drive system of an internal combustion engine that transmits the rotational force of the crankshaft to the camshaft by installing a chain tensioner device that presses the shoe on one chain, the sliding surface of the shoe makes the tangential speed of the chain supply the lubricating oil of the other chain. A chain drive device, characterized in that it is formed into a curved surface that faces the portion. 2. A first chain tensioner device for pressing the first shoe on the first chain and a second chain tensioner device for pressing the second shoe on the second chain, and the sliding surface of the second shoe on the crank sprocket. The first chain is circulated facing the sliding surface of the second shoe while facing each other, and the sliding surface of the first shoe has a tangential velocity of the first chain with respect to the lubricating oil on the entry side of the second shoe of the second chain. The chain drive device according to claim 1, wherein the chain drive device is formed in a curved surface facing the supply portion.