JPH1037942A - Lubricating device for four-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure oil pressure of a lubricating oil to crank journals to which a large load is applied higher than that of the other crank journals. SOLUTION: This four-cycle engine 21 is constituted so that a flywheel magneto 43 is arranged on one end of a crankshaft 26, and a cam chain drive sprocket 45 is arranged on the other end of the crankshaft 26, respectively, and crank journals 27a to 27e of the crankshaft 26 are rotatably supported by plural bearing parts 40a and 40b arranged on the mating face side of a divided type crankcase 25. In this case, among contact surfaces of the bearing parts 40a and 40b and the crank journals 27a to 27e, the quantity of a lubricating oil supplied to the crank journals 27a and 27e adjacent to the flywheel magneto 43 and the cam chain drive sprocket 45, is increased more than the quantity of a lubricating oil supplied to the other crank journals 27b to 27d.

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 a four-stroke engine.

[0002]

2. Description of the Related Art As shown in FIG. 4, for example, a crankshaft 2 of a four-cycle engine 1 mainly includes a crank journal 3, a crank web 4, and a crank pin 5. The crankshaft 2 is held by a portion of the crank journal 3 supported by a crankcase 7 via a bearing 6. Crankshaft 2 of a multi-cylinder engine, for example, a four-cylinder engine
Is generally supported at five points.

Since the crankshaft 2 rotates at a high speed and receives a large load, it is necessary to always lubricate the crank journal 3. Therefore, for example, the lubricating oil stored in the oil pan 8 is pumped up by the oil pump 9, filtered by the filter 10, and then disposed on the contact surface between the crank journal 3 and the bearing 12 of the crankcase 7 via the main gallery 11. The bearing 6 is guided to the bearing 6.

A communication passage 13 communicating with the main gallery 11 and the contact surface of the bearing 12 is formed inside the bearing 12 of the crankcase 7.
Is provided with an oil supply passage 14 connected to the communication passage 13 so as to guide lubricating oil not only to the crank journal 3 but also to the crank pin 5. Then, the lubricating oil is uniformly distributed to each crank journal 3 (for example, in Japanese Utility Model Laid-Open No. 59-1914).
No. 13).

On the other hand, a four-cycle multi-cylinder engine 1 has a flywheel magneto 15
And a drive sprocket 18 to which a cam chain 17 for driving a camshaft 16 is connected at the opposite end.

[0006]

When a flywheel magneto or a drive sprocket is provided at the end of a crankshaft, the load applied to the adjacent crank journal tends to be larger than that of other crank journals.

However, since the amount (oil pressure) of the lubricating oil supplied to each of the crank journals is uniform, there is a possibility that "galling" or "scuffing" may occur in the crank journal under a large load.

The present invention has been made in view of the above circumstances, and provides a lubricating device for a four-stroke engine capable of securing a higher oil pressure of lubricating oil to a crank journal on which a large load is applied than that of other crank journals. The purpose is to do.

[0009]

According to a first aspect of the present invention, there is provided a lubricating apparatus for a four-stroke engine, wherein a flywheel magneto is provided at one end of a crankshaft. In a four-cycle engine in which a cam chain drive sprocket is provided at the other end of the crankshaft, and a crank journal of the crankshaft is rotatably supported by a plurality of bearings provided inside the mating surface of the split crankcase, Of the contact surface between the bearing portion and the crank journal, the amount of lubricating oil supplied to the crank journal adjacent to the flywheel magnet and the cam chain drive sprocket is determined by the amount of lubricating oil supplied to the other crank journals. That's more.

In order to solve the above-mentioned problem, a main gallery is provided on the downstream side of the oil pump, and the main gallery is divided into two sections to form a first gallery and a second gallery. While connecting the first gallery and the second gallery to a pair of oil passages branched from the outlet of the oil filter, while lubricating oil from the first gallery to the flywheel magnet side crank journal, Further, the lubricating oil from the second gallery is guided to the crank journal on the cam chain drive sprocket side.

[0011]

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

FIG. 1 is a longitudinal sectional view showing a first embodiment of a water-cooled four-cycle parallel four-cylinder engine for a motorcycle to which the present invention is applied. FIG. 2 is a sectional view taken along the line II-I of FIG.
It is sectional drawing which follows the I line. As shown in FIGS. 1 and 2, the outer shape of the engine 21 mainly includes a cylinder head cover 22, a cylinder head 23, a cylinder block 24, and a crankcase 25.

A crankshaft 26 is arranged in the crankcase 25. The crankshaft 26 mainly includes a crank journal 27, a crank web 28, and a crank pin 29. A balance weight 30 is provided on one side of the crank web 28, and a crank pin 28 is provided on the other side of the crank web 28. 29 is connected integrally with another crank web 28. The large end 31 a of the connecting rod 31 is connected to the crank pin 29, and the piston 33 is connected to the small end 31 b of the connecting rod 31 via the piston pin 32. Note that, for convenience, the crank journals 27 of the present embodiment are first crank journals 2 from the left in FIG.
7a, a second crank journal 27b,... A fifth crank journal 27e.

A piston 33 is provided in the cylinder block 24.
Are slidably accommodated in the vertical direction in the figure. A combustion chamber 34 is formed in a space between the cylinder head 23 and the piston 33, and a spark plug 35 is screwed to the center of the combustion chamber 34 from outside.

The reciprocating stroke of the piston 33 is converted into a rotational motion by the crankshaft 26, and a primary drive gear 36 provided on the right side of the crankshaft 26 in FIG. The power is transmitted to drive wheels (not shown) via the shaft 38 and the drive shaft 39.

The crankcase 25 is of a split type, for example, is divided into three parts in the vertical direction in the figure, and is composed of an upper crankcase 25a, a center crankcase 25b, and a lower crankcase 25c. Upper crankcase 25a and center crankcase 25b
The bearing portion 40 of the crankshaft 26
a and b are formed by being divided into upper and lower parts, respectively. For example, metal bearings 41 are provided on these bearing portions 40a and 40b.
Are arranged to rotatably support the crank journals 27a to 27e of the crankshaft 26 from above and below.

A charging device 42 is provided at one end of the crankshaft 26. The charging device 42 includes a flywheel magneto 43 and a stator coil 44,
A flywheel magneto 43 fixed to one end of the crankshaft 26 is configured to generate power by rotating around a stator coil 44.

On the other hand, a cam chain drive sprocket 45 is provided at the other end of the crankshaft 26. The cam chain drive sprocket 45 is provided with a camshaft 47 of a valve train 46 provided in the cylinder head 23.
The cam chain 4 is attached to the cam sprocket 48 provided at the end.
9 is operatively connected. Then, the rotation of the crankshaft 26 is transmitted to the camshaft 4 via the cam chain 49.
7, the valve train 46 is actuated,
The intake and exhaust valves 50, 50 are opened and closed. The upper part of the cylinder head 23 is closed by the cylinder head cover 22.

The engine 21 is provided with an engine lubrication device 51, and the lower crankcase 25
Lubricating oil stored in an oil pan 52 provided at a lower portion is pumped by an oil pump 53 to various parts of the engine 21 such as the crankshaft 26, the valve gear 46, the transmission mechanism 37, and the like via an oil filter 54. Reference numeral 55 denotes a strainer for removing relatively large foreign matter in the lubricating oil. The lubricating oil that has lubricated each part of the engine 21 falls naturally in the crankcase 25, or is returned to the oil pan 52 via an oil return hole, an oil return passage, and the like (not shown), and is recirculated.

For example, a main gallery 56 is arranged on the upper part of the lower crankcase 25c in parallel with the crankshaft 26 and coaxially. Main gallery 56
Is divided into two, the first gallery 56a and the second gallery 56
b, and are respectively connected to a pair of oil passages 57a and 57b branched from the outlet of the oil filter 54.

A contact surface with the metal bearing 41 and a main gallery 56 are provided inside each bearing portion 40b (supporting the lower half of the crankshaft 26) of the crankshaft 26 formed in the center crankcase 25b.
Are formed respectively. Further, an oil supply passage 59 connected to these communication passages 58a to 58e is provided inside the crankshaft 26, and each bearing portion 40a (the upper half of the crankshaft 26) of the crankshaft 26 formed in the upper crankcase 25a is provided. The lubricating oil is also guided to the crankpin 29.

Incidentally, one main gallery 56, for example, the first gallery 56a is connected to communication paths 58a to 58c to the first to third crank journals 27a to 27c, and the other main gallery 56, for example, the second gallery 56b is the fourth and fifth crank journal 27
d, 27e are connected to communication paths 58d, 58e. Also, one oil passage 57a from the oil filter 54
Is connected to the first gallery 56a at a position closest to the crank journal 27 closest to one end of the crankshaft 26, for example, the communication path 58a to the first crank journal 27a, and the other oil path 57b from the oil filter 54 is connected to the first gallery 56a. The portion of the crank journal 27 closest to the other end of the crankshaft 26, for example, a portion closest to a communication path 58e to the fifth crank journal 27e, is connected to the second gallery 56b.

FIG. 3 shows a second embodiment of the present invention, in which only the crankshaft 26, its bearing portion 40, and a part of the lubricating device 51 are enlarged. The same components as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 3, in the second embodiment, a first gallery 156a and a second gallery 156b are provided on an upper portion of a lower crankcase 25c in a direction parallel to and coaxial with the crankshaft 26. Main gallery 156 is arranged.

One of the main gallery, for example, the first gallery 156a is connected to the communication paths 58b to 58d to the second to fourth crank journals 27b to 27d, and the other main gallery, for example, the second gallery 1
56b is the first and fifth crank journals 27a, 2
7e are connected to communication paths 58a and 58e. One oil passage 57a from the oil filter 54 is connected to the first gallery 156a, and the other oil passage 57b from the oil filter 54 is connected to the second gallery 15a.
6b.

Next, the operation of the present embodiment will be described.

When the flywheel magnet 43 and the cam chain drive sprocket 45 are provided at the end of the crankshaft 26, the crank journals 27 adjacent to them, that is, the first and fifth crank journals 27 are provided.
a, 27e is applied to the other crank journal 2
7, that is, the second to fourth crank journals 27b to 27
It tends to be larger than 7d.

Then, each of the crank journals 27a-2
If the amount (oil pressure) of the lubricating oil supplied to 7e is made uniform, the first and fifth crank journals 27a and 27e, which are subject to a large load, will have "galling" and "scuffing".
May occur.

Therefore, as shown in the first embodiment of the present invention, the main gallery 56 is divided into two parts.
a and the second gallery 56b, and the oil filter 5
4 and a pair of oil passages 57a, 57b branched from the outlet
The first gallery 56a is connected to the second gallery 56b, and the first gallery 56a is connected to the first to third crank journals 27a to 27c.
c and, for example, the second gallery 56b is connected to the fourth and fifth crank journals 27d and 27e.
d, 58e, and one oil passage 57a from the oil filter 54 is connected to the first gallery 56a at a position closest to the communication passage 58a to the first crank journal 27a. If the other oil passage 57b is connected to the second gallery 56 at a position closest to the communication passage 58e to the fifth crank journal 27e, the second and fifth crank journals 27a and 27e, which are subjected to a large load, are connected to the second to fifth crank journals 27a and 27e. Lubricating oil is supplied in a larger amount (high pressure) than the fourth crank journals 27b to 27d. Therefore,
The risk of "galling" and "scuffing" can be reduced.

Further, as shown in a second embodiment of the present invention, the main gallery 156 is divided into
56a and a second gallery 156b, and a pair of oil passages 57a,
57b, a first gallery 156a and a second gallery 156b
For example, the first gallery 156a is connected to the communication paths 58b to 58d to the second to fourth crank journals 27b to 27d, and the second gallery 156b
Are connected to the communication passages 58a, 58e to the first and fifth crank journals 27a, 27e, respectively, similarly to the first embodiment, the second to fifth crank journals 27a, 27e to which a large load is applied are connected to the second to fifth crank journals 27a, 27e. Lubricating oil is supplied in a larger amount (high pressure) than the fourth crank journals 27b to 27d. Therefore, "gnawing"
Or "scuff" can be reduced.

In the above-described two embodiments, an example in which the present invention is applied to lubrication of the crankshaft 26 is shown. For example, the camshaft 47 is provided with a cam sprocket 48 at one end similarly to the crankshaft 26. Therefore, there is a possibility that a "snag" or "scuff" may occur in a journal portion (not shown) adjacent to the cam sprocket 48. Therefore, if the present invention is applied to lubrication of the camshaft 47, the same effect as that of the crankshaft 26 can be obtained.

[0032]

As described above, according to the lubricating device for a four-stroke engine according to the present invention, the flywheel magneto is provided at one end of the crankshaft, and the cam chain drive sprocket is provided at the other end of the crankshaft. In addition, in a four-cycle engine in which the crank journal of the crankshaft is rotatably supported by a plurality of bearing portions provided inside the mating surface of the split crankcase, the contact surface between the bearing portion and the crank journal includes: Since the amount of lubricating oil supplied to the crank journal adjacent to the flywheel magneto and the cam chain drive sprocket is larger than the amount of lubricating oil supplied to the other crank journals, the crank journal to which a large load is applied, Other cranks An amount greater than Naru (higher pressure)
Can supply lubricating oil and reduce the occurrence of "galling" and "scuff".

A main gallery is provided on the downstream side of the oil pump. The main gallery is divided into two to form a first gallery and a second gallery, and a pair of oil passages branching from an outlet of the oil filter are provided. While connecting the first gallery and the second gallery, the lubricating oil from the first gallery is applied to the crank journal on the flywheel magneto side, and the lubricating oil from the second gallery is applied to the cam chain drive sprocket side. The lubricating oil is supplied to the crank journal that receives a large load in a larger amount (higher pressure) than the other crank journals, because it is configured to guide each to the crank journal, reducing the occurrence of "galling" and "scuff" it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a water-cooled four-cycle parallel four-cylinder engine for a motorcycle showing a first embodiment of a lubrication device for a four-cycle engine according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a longitudinal sectional view of an engine in which only a part of a crankshaft, a bearing thereof, and a lubricating device according to a second embodiment of the present invention are enlarged.

FIG. 4 is a longitudinal sectional view of a conventional 4-cycle parallel 4-cylinder engine.

[Explanation of symbols]

 Reference Signs List 21 engine 25 crankcase 26 crankshaft 27a first crank journal 27b second crank journal 27c third crank journal 27d fourth crank journal 27e fifth crank journal 40a, 40b bearing part 41 metal bearing 43 flywheel magneto 45 cam chain drive sprocket 46 Valve operating device 51 Lubricating device 53 Oil pump 54 Oil filter 56, 156 Main gallery 56a, 156a First gallery 56b, 156b Second gallery 57a, 57b Oil passage 58a-58e Communication passage

Claims (2)

[Claims] A flywheel magneto is provided at one end of a crankshaft, a cam chain drive sprocket is provided at the other end of the crankshaft, and a plurality of bearings provided inside a mating surface of a split crankcase. In a four-stroke engine that rotatably supports the crank journal of the crankshaft,
The bearings 40a and 40b and the crank journal 2
7a to 27e, the flywheel magneto 43 and the cam chain drive sprocket 4
5, the amount of lubricating oil supplied to the crank journals 27a and 27e adjacent to the other crank journals 27a and 27e is reduced.
A lubricating device for a four-stroke engine, wherein the lubricating oil is supplied in an amount larger than b to 27d. 2. A main gallery 56 is provided downstream of the oil pump 53. The main gallery 56 is divided into two to form a first gallery 56a and a second gallery 56b, and branch from an outlet of the oil filter 54. The first gallery 56a and the second gallery 56b are connected to the pair of oil passages 57a and 57b, and the lubricating oil from the first gallery 56a is supplied to the crank journals 27a to 27c on the flywheel magnet side 43, and The lubricating device according to claim 1, wherein the lubricating oil from the second gallery (56b) is guided to the crank journals (27d, 27e) of the cam chain drive sprocket (45).