JPS6285107A - Cam shaft supporting mechanism of dohc engine for motorcycle - Google Patents

Abstract

PURPOSE:To shorten the length of a cam shaft with the provision of an modified lubricating structure for symplifying the lubricating structure by supporting a cam shaft with bearing pedestals located between cam surfaces at least in one end cylinder in a supporting mechanism. CONSTITUTION:The titled engine 10 has more than two intake valves and more than one exhaust valve for each of the plural number of cylinders which is arranged to the direction of the width of a car, and an intake and an exhaust cam shaft 14 which effect the closing motion of each of the valves, are provided to the direction of cylinder arrangement. In this case, an oil passage 14a is formed in each of the cam shafts along the shaft axis, and the cam shafts are supported by both a bearing section 12a between cylinders, and a bearing section 12b between cam surfaces. And an oil inlet port 12d is formed in a head bolt hole 12c which is arranged at the right side of a cam chain chamber 11d, and the head bolt hole 12c is provided so as to be communicated with a tool accessing hole 15c which is formed on a bearing section 15b of a cam cap 15 by way of a tool accessing hole 14c which penetrates through the cam shaft 14.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a camshaft for a DOHC engine for a motorcycle, in which the width of a portion of the head cover of the engine can be narrowed without complicating the lubrication structure of the camshaft. Regarding the support mechanism.

[Conventional technology]

Recently, in so-called DOHC engines that have separate camshafts for intake valves and camshafts for exhaust valves, there is a tendency to reduce the valve angle, that is, the intersection angle of the axes of both valves. ;? In some cases, the camshaft that drives the cylinder to close is located substantially directly above the cylinder lock for tightening the cylinder lock. In such an engine, the camshaft is provided with a tool insertion tool 7L that passes through the camshaft in a direction perpendicular to the shaft, and the head bolt is tightened by inserting the tightening tool into the IIp manhole.

The camshaft support mechanism for a DOHC engine has a tool insertion hole for tightening the head bolt on the camshaft.
Conventionally, there have been two examples described below, for example.

The first conventional example shown in FIG.
It is arranged outside the cylinder part 2 between and at both ends. A bearing portion 1d is formed above the head bolt 3, and the bearing portion 1d is formed above the head bolt 3.
Attach the cam cap 6 to the hollow part 4a.
The head cover 5 supports a camshaft 4 having a camshaft 4, and is further provided with a head cover 5 that covers the camshaft 4. Further, a tool insertion hole 4b for tightening the head bolt 3 is formed in the camshaft 4 so as to be able to communicate with the head bolt hole lb, and an oil supply port IC is provided to supply lubricating oil to the one head bolt hole 1b.
is formed.

In this first conventional example, the oil supplied from the oil supply port 1e to the head bolt hole 1b is transferred to the hollow portion 4a of the camshaft 4.
The lubricating oil is supplied to each bearing portion 1d through the lubricant, thereby lubricating each bearing portion 1d.

A second conventional example shown in FIG. 6 is a bearing portion IR that supports a camshaft 4 between cam surfaces 4c, 4c formed corresponding to intake valves or exhaust valves for each cylinder.

1f... are formed, oil supply holes 1g, 1g... are formed in each of the bearing parts if, if..., and oil is supplied to each oil supply hole tg, tg... has been done.

[Problem that the invention seeks to solve]

In the first conventional example, since the bearing portions 1d of the camshaft 4 are also formed outside the cylinder portions 2 at both ends, the camshaft 4 is
becomes longer, and the width of the head cover 5 becomes larger. When this engine is mounted on a motorcycle, the protruding portion of the head cover 5 tends to interfere with the rider's legs, and the degree of freedom in riding is restricted. Furthermore, depending on the type of frame, the main pipe may be located outside of the head cover 5, and in such frames, the frame width becomes wider, which limits the riding position, and the engine is mounted in a forward-leaning position. In this case, the down tube will be located outside of this head cover, resulting in a problem that the frame width will become wider by the amount of the above-mentioned overhang.

In addition, in the second conventional example, since the camshaft 4 is supported between the cam surfaces 4C, the bearing part 1f does not protrude outside the two cylinders, and the frame width increases. problem can be solved. However, in this second conventional example, there is a problem in that it is necessary to adopt a structure in which oil is supplied separately to each bearing part 1f, which complicates the camshaft lubrication structure accordingly. The reason for this separate supply of oil is that in the second conventional example, the hollow portion 4 of the camshaft 4
a is open to the cam chamber 1h, so this hollow part 4a
This is because it cannot be used as an oil passage.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional device, to reduce the width of a part of the head cover without complicating the camshaft lubrication structure, and to improve the degree of freedom of the riding position. The present invention provides a camshaft support mechanism for a DOHC engine for two-wheeled vehicles.

[Means for solving problems]

The present invention provides a motorcycle Ichikawa DOHC engine in which a head bolt is disposed approximately directly below the camshaft and a tool insertion hole for tightening the head bolt is formed in the camshaft, and the present invention provides at least a bearing portion that supports each of the camshafts. An oil supply is formed between the two cam surfaces corresponding to the cylinder at one end to supply lubricating oil to one head bolt hole that communicates with the tool insertion hole. This is a camshaft support mechanism in which an oil hole is formed between the cam surfaces to communicate an oil passage with a bearing between the cam surfaces.

Here, in a so-called three-valve engine having two intake valves and one exhaust valve, the bearing portion between the cam surfaces may be provided only for the intake valve camshaft.

[Effect]

In the camshaft support mechanism according to the present invention, in at least one end of the cylinder, the camshaft is supported between the cam surfaces, so the camshaft becomes shorter and the width of a portion of the cylinder becomes narrower. Also, since the one head bolt hole that communicates with the tool insertion hole communicates with the oil supply port from the outside,
The oil from this oil supply port passes through the oil path of the camshaft and the adjacent tool insertion hole to lubricate the bearings between each cylinder, and also passes through the oil passage and oil hole to the bearings between the cam surfaces. Therefore, the lubrication structure does not become complicated.

(Example〕 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 4 show one embodiment of the present invention, and in the figures, 30 is a DOHC having a camshaft support i side according to the present embodiment.
This is a motorcycle equipped with an engine 10. A front fork 23 that supports a front wheel 22 is pivotally supported at the front end of a frame 21 of the motorcycle 30, and a rear fork 25 that supports a rear end 24 is pivotally supported at the rear end. The engine IO is mounted approximately in the middle of the frame 21.

The engine 10 is a DOHC 4-cylinder 4-pulp engine, and the lower surface of the cylinder head 11 of the engine 10 has four combustion recesses 11a, 11a, etc. corresponding to the four cylinders of the cylinder block (not shown). Arranged in the width direction. Further, 11d is a cam chain chamber, in which a cam chain that transmits power from the crankshaft to a camshaft, which will be described later, is disposed.

Further, cam chambers 12 extending in the vehicle width direction are formed at the front and rear sides of the upper part of the cylinder 11, and each cam chamber 1
Exhaust camshafts 13.2 each drive the fJF air valves. An intake camshaft 14 that drives the intake valve is provided. Each of the camshafts 13 and 14 is hollow, and the hollow portions serve as oil passages L3a and 14a. 1-
A cam surface 14b protrudes from a portion of the cam shaft 13 and 14 corresponding to each of the valves, and the cam surface 14b is connected to each valve.
A valve lifter is provided between the valve lifter and the valve lifter.

Between each cylinder of each cam chamber 12, that is, each combustion recess 11a
An inter-cylinder bearing portion 12.1+ and an inter-cam surface bearing portion 12b are formed at positions corresponding to the cam surfaces of the cylinders at both ends. The camshaft 13.14 has bearing portions 12a, 12b.
and a cam cap 1 that is removably attached on top of these.
It is rotatably supported by respective bearing portions 15a and 15b of No.5.

The bearing portion 15a and the bearing portion 12b are connected to the oil passages 13a, 14 through the oil 7L13d, 14d.
It communicates with a. Note that 16 is a head cover disposed above each of the cam chambers 12.

The cylinder head 11 is fixed to the lower cylinder block by head bolts 17, and the bolts 17 are arranged below each camshaft 13 and 14 between each cylinder and outside the cylinders on both sides. It is set up. In addition, the bearing portion 15b of the cam cap 15 has the above! A tool insertion hole 15C is formed through which a tool for tightening the nut 11a of the bolt 17 is inserted.
It can communicate with the head bolt hole 12c via the hole 4c. Further, an oil supply port 12d is formed in the head bolt hole 12c on the right side of the cam chain chamber lid in FIG. . Further, an oil supply passage 20 is connected to the supply port 12d. In addition, 18 is the sprocket that drives the camshaft 1.3.14, and 191.19b is the sprocket that drives the camshaft 13.1.
4 and the tool insertion hole 15c of the cam cap 15.

Next, the effects of this embodiment will be explained.

First, in the engine 10 of this embodiment, the Dokahar 16
To explain the narrowing of the width, the camshafts 13.14 are supported between the cam surfaces in the cylinder sections at both ends, so the camshafts 13.14 are supported between the left and right outermost cam surfaces. There is no need to extend it further outward, and for that reason, Dokahar 16
Both sides of the rim are recessed inward from both sides of the nindahenod 11.

Next, if we explain the 2゛4 sliding of the camshafts 13 and 14,
Lubricating oil is supplied from the oil supply port 12d to the head port hole 12c at the center of the υF air side. This oil is applied to the central inter-cylinder bearing section 12 in which the acid head bolt hole 12C is formed.
The oil is supplied to the adjacent bearing part 12-a through the oil passage 13a while lubricating the oil hole], 3 d
through the cam surface bearings 12b to lubricate these bearings 123.12b. Also, the camshaft 1 on the intake side
4 is supplied with the oil through the communication passage 12e, and is lubricated similarly to the camshaft 13 on the exhaust side.

In this way, in this embodiment, all the bearing parts are lubricated by simply supplying oil to one of the head port holes 12C formed in the bearing part, and the lubrication structure is not complicated. The head cover 16 is supported between both ends of the cam shaft 13 and 14, and the head cover 16 is shortened by the length of the cam shaft 13 and 14.
The head cover 16 also has a short length, and as a result, the head cover 16 hardly hits the occupant's legs, improving the degree of freedom of the lighting position. Also the frame format.

Even when the main pipe and down tube are located outside the head cover 16 due to vehicle installation, an increase in frame width can be suppressed.

Although the above embodiment describes a 4-valve engine, the present invention can also be applied to a 3-valve engine with two intake valves and one exhaust valve. In this case, only the camshaft on the intake valve side is connected to the outermost cylinder. In the above example, the camshaft is supported between two cam surfaces at both the left and right end cylinders, but it does not necessarily have to be supported between the cam surfaces at both ends. Even if only one end is supported between the cam surfaces, the width of the head cover can be reduced accordingly. Furthermore, although the above embodiments have been described using an example of a four-cylinder engine, the present invention can be applied to any engine having two or more cylinders.

〔Effect of the invention〕

As described below, according to the camshaft support mechanism for a DOHC engine for a motorcycle according to the present invention, a camshaft having an oil passage is supported between the cam surfaces in at least one end of the cylinder, and the camshaft is supported between the cam surfaces in the other cylinder. Support between the cylinders,
An oil supply port is provided in one of the bearings between the cylinders, and the bearing between the cam surfaces and the oil passage are communicated with each other, so the width of the part of the head cover can be narrowed without complicating the camshaft lubrication structure, making it easier to ride. This has the effect of increasing the degree of freedom in positioning.

[Brief explanation of drawings]

FIG. 1 is a half-sectional front view of a Norinda head to which a camshaft support mechanism according to an embodiment of the present invention is applied, and FIGS. 2 and 3 are sectional views taken along line nn in FIG. 4 is a side view of a motorcycle equipped with the engine of the above embodiment, and FIGS. 5 and 6 are a sectional view taken along line In, and FIGS. FIG. 7 is a half-sectional front view showing a second conventional example. In the figure, 10 is the engine, 11 is the throat to the cylinder,
lla is the combustion recess (cylinder>, 12a is the inter-cylinder bearing part, 1
2b is a bearing between cam surfaces, 13.14 is a camshaft, 13a,
14a is an oil passage, 13c and 14c are tool insertions! death,
13d, 14dL; i oil hole, 17 is a head bolt. Figure 4

Claims (1)

[Claims] (1) Multiple cylinders are arranged in the vehicle width direction, and each cylinder has two
providing one or more intake valves and one or more exhaust valves;
An intake valve camshaft and an exhaust valve camshaft are arranged in the direction in which the cylinders are arranged, and among the head bolts for fixing the cylinder head to the cylinder block, at least the head bolt between each cylinder is arranged substantially directly below each camshaft. In addition to establishing
In a DOHC engine for a motorcycle in which a tool insertion hole for tightening a head bolt substantially directly below is formed through each camshaft, an oil passage is formed along the axis of each camshaft to support each camshaft. A bearing portion is provided between at least two cam surfaces corresponding to the cylinder at one end, and the oil supply port is formed to communicate with one head bolt hole opening in the tool insertion hole portion, and the bearing portion between the cam surfaces A camshaft support mechanism for a DOHC engine for a motorcycle, characterized in that each of the camshafts is provided with an oil hole that communicates with the oil passage.