JP2002242638A - Lubricating device of ohc type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating device for a general-purpose OHC type engine whose timing adjusted valve system is lubricated certainly without resulting in an increase of the number of component parts. SOLUTION: The OHC type engine in inclined form includes timing adjusted valve system which is lubricated by scraping up the oil stored in the lower part of a crank case using a scraper 38 installed at the major end 26 of a connecting rod 24. The scraper 38 is composed of an arm 69 extending from a lower located member 39 in the radial direction of a crank shaft and a dip piece 70 installed upright at the tip of the arm 69 and assumes an L-shape as a whole. The dip piece 70 is located on that side of the arm 69 confronting the timing adjusted valve system. The scraper 38 makes swinging motions following an elliptical track in association with the rotation of the crank shaft, and the oil is splashed up by the dip piece 70 to lubricate the timing adjusted valve system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for an OHC type engine, and more particularly to a technique which is effective when applied to an OHC type general-purpose engine in which a cylinder axis is inclined with respect to a vertical direction. is there.

[0002]

2. Description of the Related Art Conventionally, general-purpose engines of the OHV (overhead valve) type and the OHC (overhead camshaft) type have been widely used as power sources for mowing machines, power sprayers, generators and the like. For example, Japanese Patent Application Laid-Open No. 10-280932 discloses an OHV type engine in which the cylinder axis is inclined to reduce the size of the device. Also, Japanese Patent Application Laid-Open No. 8-1774
No. 41 discloses an OHC that improves lubrication of a valve train by using an oil dipper that rotates together with a crankshaft.
A type engine is disclosed.

[0003] In such a general-purpose engine, a so-called splash system (splashing system) is used as a lubrication system for a timing valve operating system such as a chain, a sprocket, and a valve operating cam from the viewpoint of cost and size. There are many. In this splash method, an oil pump is not used, and oil in an oil pan is scraped up by a paddle-shaped (JP-A-10-280932) or water-wheel-shaped (JP-A-8-177441) oil dipper, and the oil droplets are sprayed. Lubrication of the valve train.

[0004]

However, in the case of a lubrication system as disclosed in Japanese Patent Application Laid-Open No. 8-177441, an oil dipper is arranged on a shaft separate from the crankshaft, so that the number of parts increases and the structure of the device is complicated. And there is a problem that the cost increases. Further, since the oil is scraped up by the water wheel-shaped member, there is a problem that not only the stirring resistance is large and the load is increased, but also the oil temperature is increased. Further, there is a disadvantage that the height of the engine is increased by the amount of the oil dipper.

On the other hand, in the apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 10-280932, oil is scraped up by a dipper provided at the large end of the connecting rod, so that the valve train can be lubricated without increasing the number of parts. . In addition, since the paddle-shaped dipper moves so as to cut off the oil, the stirring resistance is small and the oil temperature rise is small. However, in such a dipper, although oil can be scattered and diffused in the circumferential direction of the connecting rod, the oil cannot be scattered to a distant position in the side direction. Therefore, the valve train is offset with respect to the connecting rod (displaced in the longitudinal direction of the crankshaft).
In the case of an arranged OHC type engine, such a dipper cannot sufficiently lubricate the valve train.

That is, in an OHV type engine as disclosed in Japanese Patent Application Laid-Open No. 10-280932, a valve operating cam can be arranged near an oil dipper, so that a valve operating system can be lubricated by a paddle-shaped dipper. However, O
In the HC type engine, since the chain for the timing valve and the cog belt are arranged offset from the connecting rod, there is a problem that the paddle-shaped dipper cannot scatter oil to the position of the chain or the like. .
In particular, in engines with large displacement, lubrication on the chain side tends to be insufficient, and a lubrication structure with higher efficiency has been demanded in consideration of lubrication of the valve operating cam surface.

An object of the present invention is to reliably lubricate a timing valve operating system without increasing the number of components in an OHC type general-purpose engine.

[0008]

A lubricating device for an OHC type engine according to the present invention drives a valve operating cam arranged on a cylinder head side of the engine in synchronization with a crankshaft by a timing valve operating system, and drives the engine. An OHC type engine lubricating device for lubricating the timing valve system by scraping up oil stored in a lower portion of a crankcase of the engine by a scraper provided on a large end portion of the connecting rod, wherein the scraper comprises: It is characterized in that the arm is formed in an L-shape having an arm extending in the radial direction of the crankshaft and a dip piece erected at the tip of the arm and extending in the axial direction of the crankshaft.

According to the present invention, the L-shaped scraper can efficiently splash oil splashes upward, and can reliably supply oil to the timing valve system even when the engine is inclined. Can be. Therefore,
Lubricating oil can be reliably supplied to the timing valve system of the OHC engine without increasing the number of parts.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view showing a configuration of an OHC engine using a lubricating device according to an embodiment of the present invention, and FIG. 2 is a sectional view of the engine of FIG. 1 in a cylinder axis direction.

The engine shown in FIG. 1 is a single-cylinder four-cycle gasoline engine, and is a so-called inclined OHC engine in which the cylinder axis CL is inclined by an angle θ with respect to the vertical direction. In this engine, the engine body 1 is
The crankcase 3 is formed integrally with the lower side of the cylinder 2 and is formed of iron or a light alloy such as an aluminum alloy. A cylinder head 4 made of an aluminum alloy is attached to the upper side of the cylinder 2.
A rocker cover 5 made of sheet metal or synthetic resin is placed above the cylinder head 4.

The right side surface of the crankcase 3 in FIG. 1 is largely open and serves as a main bearing case mounting surface 6. A main bearing case 7 made of an aluminum alloy is mounted on the main bearing case mounting surface 6. Thereby, a crank chamber 8 is formed in the crankcase 3 and an oil pan 10 in which lubricating oil (hereinafter, abbreviated as oil) 9 is stored is formed below the crank chamber 8.

A main bearing 11a is press-fitted and fixed in the bearing case 7, and one end of the crankshaft 12 is supported there. Also, the main bearing 11a
An oil seal 13a is press-fitted and fixed to the outside.

A main bearing 11b is press-fitted and fixed to a wall surface 14 of the crankcase 3 opposite to the main bearing case mounting surface 6. The other end of the crankshaft 12 is supported by the main bearing 11b. An oil seal 13b is also provided outside the main bearing 11b.
The oil 9 stored in the oil pan 10 is removed from the crankshaft 12 by the 3a and 13b.
It does not leak outside.

A flywheel 15 and a cooling fan 16 are attached to an end of the crankshaft 12 extending from the wall surface 14 to the outside of the crankcase 3. The cooling fan 16 is provided outside the crankcase 3 and the housing 5.
7 and rotates with the crankshaft 12 to introduce cooling air from outside the housing 57. Then, the engine body 1, the cylinder head 4, and the like are cooled by the introduced cooling air. Further, a recoil device 17 is provided outside the housing 57, and the recoil lever 17a is provided.
Is manually pulled to rotate the crankshaft 12 and start the engine.

A cylinder bore 18 is formed inside the cylinder 2. The piston 1 is located in the cylinder bore 18.
9 are slidably fitted. The upper end side of the cylinder bore 18 is closed by the cylinder head 4, and a combustion chamber 21 is formed by the top surface of the piston 19 and the bottom wall surface 20 of the cylinder head 4. Note that an intake valve 22, a spark plug 68, an exhaust valve (not shown), and the like are exposed above the combustion chamber 21.

A small end 25 of a connecting rod 24 is rotatably connected to the piston 19 via a piston pin 23. A crank pin 27 of the crankshaft 12 is rotatably connected to the large end 26 of the connecting rod 24. Thus, the crankshaft 12 rotates with the vertical movement of the piston 19.

On the other hand, a camshaft 28 is arranged in the cylinder head 4 on the cylinder axis CL in parallel with the crankshaft 12. The camshaft 28 has a structure in which the valve cam 29 and the sprocket 31 are integrally formed. The valve operating cam 29 is driven by the timing valve operating system 30 in synchronization with the crankshaft 12.

On the other hand, a sprocket 32 is fixed to the crankshaft 12. Further, a chain chamber 50, 51 is formed in the cylinder 2 and the cylinder head 4, and the two sprockets 31, 32 are connected by a chain 33 provided in the chain chambers 50, 51. ing. And these sprockets 31,
The timing valve train 30 is formed by the chain 32 and the chain 33. The number of teeth of the sprocket 31 is twice the number of teeth of the sprocket 32, and
Is rotated twice, the valve cam 29 rotates once. Further, the chain 33 includes a chain tensioner 55
The tension is appropriately given by

A cam surface 29a is formed on the valve cam 29, and a slipper 35 formed at one end of a rocker arm 34 is in sliding contact with the cam surface 29a. The rocker arm 34 is provided with two rocking arms for intake and exhaust. These rocker arms 34 are attached so as to be swingable about a rocker shaft 36 supported by a rocker support 59, respectively. The other end of the rocker arm 34 is connected to the distal end of the intake valve 22 or an exhaust valve (not shown) via an adjusting screw 56. When the rocker arm 34 swings by the valve cam 29, the intake valve 22 and the exhaust valve are driven. Further, the intake valve 22 and the exhaust valve are urged in the valve closing direction by a valve spring 37, whereby the intake valve 22 and the like move the valve operating cam 29.
It is opened and closed with the rotation of.

On the other hand, the timing valve system 30 includes the connecting rod 24
Is lubricated by a scraper 38 provided at the large end 26 of the main body. 3A and 3B are explanatory views showing the configuration of the connecting rod 24, wherein FIG. 3A is a side view and FIG. 3B is a front view. Also,
FIG. 4 is a perspective view of a tip portion of the scraper 38.

As shown in FIG. 2, the scraper 38 extends downward from the lower member 39 of the large end portion 26, that is, extends in the radial direction of the crankshaft 12, and has a trajectory as shown by a one-dot chain line in FIG. While drawing the crankshaft 12
Swings with the rotation of. As a result, the oil 9 accumulated in the oil pan 10 is scraped up, and when the scraper 38 comes out of the oil level 40, the oil 9 is
The lubrication of the timing valve system 30 is performed.

In the present invention, the scraper 38 comprises an arm 69 extending from the lower member 39 in the radial direction of the crankshaft 12 and a dip piece 70 erected at the tip of the arm 69, as shown in FIG. ), The whole is L
It is formed in a character shape. Here, the dip piece 70
As shown in FIG. 1, the arm 69 is formed on the side facing the timing valve train 30, and extends in the axial direction of the crankshaft 12. Also, the dip piece 70 is shown in FIG.
As shown in FIG. 4, the inclined surface is formed so that the rear side in the moving direction rises, and the upper surface side is concave.

As shown in FIG. 2, the scraper 38 swings while drawing an elliptical orbit as the crankshaft 12 rotates. Thereby, the dip piece 7
The oil 9 is scraped up by 0 and is jumped up above the dip piece 70 as shown in FIGS. In this case, in the scraper 38, the oil 9
By the function of the inclination of 0 and the concave surface, it is efficiently jumped up above the scraper 38 and is made to fly in the direction of the chain 33.

That is, as shown in FIG. 2, when the dip piece 70 comes out of the oil surface 40, it travels at a relatively small angle. In other words, the upper surface of the dip piece 70 comes close to being parallel to the oil surface 40 and comes out of the oil reservoir. Therefore, the oil 9 can be efficiently scooped by the upper surface of the dip piece 70, and a larger amount of oil can be jumped up. The dip piece 70 is shown in FIG.
Since the oil surface 40 comes out with the right side slightly lowered in the above, the oil 9 scooped up on the upper surface is blown diagonally upward. Therefore, the oil 9 can be effectively jumped up in the direction of the chain 33 that is obliquely above the scraper 38.

The scraper 38 advances at a relatively large angle when the dip piece 70 enters the oil surface 40 as shown in FIG. That is, the vehicle enters the oil reservoir at a steep angle from the right side in FIG. Therefore, the resistance received by the scraper 38 when entering the oil level can be reduced, and the load on the engine can be reduced.

On the other hand, in the scraper 38, the dip pieces 7
The reference numeral 0 extends from the arm 69 toward the timing valve operating system 30. For this reason, even when the engine is tilted and the oil level 40 is tilted as shown by the dashed line in FIG. 1, the dip pieces 70 can hit the oil level 40 and splash oil droplets. Therefore, even when the engine is tilted, it is possible to sufficiently supply the oil to the timing valve operating system 30, and it is possible to prevent problems caused by running out of oil.

As described above, with the L-shaped scraper 38 according to the present invention, the splash of the oil 9 can be efficiently scattered upward, and the oil 9 can be applied to the chain 33 even when the engine is inclined. It is possible to reliably supply. Therefore, it is possible to reliably lubricate the timing valve system 30 of the OHC engine without increasing the number of parts. In particular, even in an engine having a large displacement, lubricating oil can be sufficiently supplied to the timing valve train 30 and the performance of the engine can be improved.

The oil 9 splashed on the chain 33 in this manner is carried to the cylinder head 4 side along with the movement of the chain 33, and the sprocket 31 and the cam surface 29 are moved.
The lubrication of a is also performed. The sprocket 32 is also lubricated by the oil 9 attached to the chain 33.

A part of the oil 9 attached to the chain 33 is shaken off by the centrifugal force on the cylinder head 4 side. That is, when the chain 33 is wound around the sprocket 31, a part thereof is
And is separated from the chain 33 in the circumferential direction. In the engine, the rocker cover 5 is disposed above the sprocket 31, and the splash of the oil 9 hits the ceiling surface 53 of the rocker cover 5. Then, the oil 9 attached to the ceiling surface 53 flows downward along the ceiling surface 53 and returns to the oil pan 10 along the chain chambers 51 and 50.

As shown in FIG. 1, a convex portion 54 is formed on a part of the ceiling surface 53 of the rocker cover 5, and the oil 9 adhered to the ceiling surface 53 drops from the convex portion 54. It is like that. The convex portion 54 is located above a sliding contact portion between the valve cam 29 and the slipper 35, and the sliding contact portion is lubricated by the oil 9 dropped from the sliding contact portion.

A gas-liquid separation chamber 43 is provided inside the cylinder head 4 separately from the chain chamber 51.
In the rocker cover 5, a gas-liquid separation chamber 45 communicating with the gas-liquid separation chamber 43 via a reed valve 44 is formed. Further, the gas-liquid separation chamber 45 is connected to an air cleaner 47 via a blow-by passage 46.
The air cleaner 47 is connected to an intake port 49 in the cylinder head 4 via a carburetor 48.

The gas-liquid separation chambers 43 and 45 supply blow-by gas stored in the crank chamber 8 to the air cleaner 4.
When the gas is refluxed to the mist 7, the mist of the oil 9 contained in the blow-by gas is separated. In the engine, the gas-liquid separation chamber 43 is open to a chain chamber 50 formed separately from the cylinder bore 18. That is, a gas inlet 52 is provided at the upper end of the chain chamber 50 of the cylinder 2, and blow-by gas flowing into the chain chamber 50 is supplied to the gas-liquid separation chamber 4 through the gas inlet 52.
3 flows into. Then, by flowing through the inside of the gas-liquid separation chamber 43, the oil mist therein is removed.
Adheres to the wall surface and separates the blow-by gas and oil mist. At this time, the oil separated in the gas-liquid separation chamber 43 is returned to the oil pan 10 along the wall surfaces of the gas-liquid separation chamber 43 and the chain chamber 50.

The blow-by gas flowing into the rocker cover 5 via the reed valve 44 is further separated into oil mist in the gas-liquid separation chamber 45. That is, the oil mist in the blow-by gas that has entered the gas-liquid separation chamber 45 adheres to the wall surface of the gas-liquid separation chamber 45, and further performs gas-liquid separation. An oil return hole (not shown) is provided on the lower surface side of the rocker cover 5, and the oil adhering to the wall surface of the gas-liquid separation chamber 45 flows out of the oil return hole into the chain chambers 51 and 50, and the chain chamber 51 , 50 and returned to the oil pan 10.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. Needless to say,

For example, in the above-described embodiment, an example in which the dip piece 70 has a curved shape having a concave upper surface is used, but a flat dip piece 70 having no unevenness may be used. is there. Further, although the configuration in which one dip piece 70 is provided on the arm 69 is shown, a plurality of such dip pieces 70 may be provided, for example, and the supply oil amount may be adjusted.

In the above-described embodiment, an example in which the present invention is applied to a single-cylinder air-cooled engine is described. However, the present invention is applied to a multi-cylinder air-cooled engine or a single-cylinder or multi-cylinder water-cooled engine. It is also possible. Further, the example in which the cylinder 2 and the crankcase 3 are formed integrally has been described. However, these may be formed separately, and the cylinder head 4 and the cylinder 2 may be formed integrally.

In addition, the example in which the timing valve system 30 is constituted by the sprockets 31, 32 and the chain 33 has been described.
It is also possible to apply other known timing valve operating systems, such as a cog pulley and a cog belt or a timing pulley and a timing belt. In the present invention, “rotation” is a concept including circular motion in both forward and reverse directions, and does not mean only circular motion in one direction.

[0039]

According to the lubricating device for an OHC type engine of the present invention, the scraper provided at the large end of the connecting rod is formed in an L-shape including an arm and a dip piece.
Oil droplets can be efficiently scattered upward. In addition, since the dip pieces are extended in the axial direction of the crankshaft, even when the engine is inclined, the dip pieces hit the oil surface, and the oil can be reliably supplied to the chain. Therefore, it is possible to reliably lubricate the timing valve train of the OHC engine without increasing the number of parts.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of an OHC engine using a lubrication device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the engine of FIG. 1 in the cylinder axis direction.

3A and 3B are diagrams showing a configuration of a connecting rod, wherein FIG. 3A is a side view and FIG. 3B is a front view.

FIG. 4 is a perspective view of a scraper tip.

[Explanation of symbols]

 Reference Signs List 3 Crank case 4 Cylinder head 9 Lubricating oil 12 Crankshaft 24 Connecting rod 26 Large end 29 Valve operating cam 30 Timing valve operating system 38 Scraper 69 Arm 70 Dip piece

Claims (1)

[Claims] 1. A valve operating cam arranged on a cylinder head side of an engine is driven by a timing valve operating system in synchronization with a crankshaft, and a crank of the engine is driven by a scraper provided on a large end portion of a connecting rod of the engine. A lubricating device for an OHC type engine for lubricating the timing valve system by scraping oil stored in a lower portion of a case, wherein the scraper includes an arm extending in a radial direction of the crankshaft; Characterized by being formed in an L-shape having a dip piece standing upright at a tip end thereof and extending toward the crankshaft axial direction.
HC type engine lubrication system.