JPH09250354A - 4-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the width of an engine narrow and to position a right and left driving side sprockets at one time when the engine is assembled in a 4-cycle engine of V-type or horizontal opposed type. SOLUTION: This V-type, 4-cycle engine has valve systems which transmit the rotation of a crank shaft 4 to the sprockets of a driven side of a cylinder head side from driving side sprockets 7F, 7R of an engine case 1b side via chains 8F, 8R on each right and left cylinder 2F, 2R. A first idle shaft 6 driven by the crank shaft 4 is disposed in the engine case 1b in parallel to the crank shaft 6 and the driving side sprocket 7R for driving the driven side sprocket of right cylinder 2R is mounted to the left end of the first idle shaft 6 and the driving side sprocket 7F for driving the driven side sprocket of left cylinder 2F is mounted to the right end of the first idle shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead camshaft type V-type engine having a plurality of cylinders, which can be applied to all engines mounted on automobiles, motorcycles, outboard motors and the like. The present invention relates to a horizontally opposed four-cycle engine.

[0002]

2. Description of the Related Art Generally, in a 4-cycle engine, a crankshaft (crankshaft) and a camshaft (camshaft) are linked by a chain, a belt or a cam gear train so that the rotation of the camshaft is constant with the rotation of the crankshaft. It has a valve drive system drive device that makes a relationship (the crankshaft rotates twice to rotate the camshaft once), and the drive device opens and closes the valve at the timing set in the engine.

FIG. 5 shows an example of a conventional valve train drive device. This device is applied to a V-type engine, and drive side sprockets b and c are provided at both left and right end portions of a crankshaft a, and the left and right drive side sprockets b and c respectively The driven side sprockets f and g of the camshafts d and e are driven via the chain h.

Further, in Japanese Patent Laid-Open No. 1-163423, in a V-type engine, a pair of left and right drive side sprockets are fixed to one side shaft end of a crankshaft, and a pair of left and right drive side sprockets are provided to the left and right cylinders. The driven side sprockets provided on the respective camshafts can be driven via belts.

In Japanese Patent Laid-Open No. 59-85405, a V-type engine is provided with an idle gear at the center of the engine and a gear train including the idle gear is formed in the center of the engine. The gear train drives the left and right cylinder camshafts.

Further, in Japanese Laid-Open Patent Publication No. 54-50718, in a V-type engine, idle shafts are arranged on both left and right sides of the engine, and drive sprockets are provided on the left and right idle shafts. Disclosed is a valve train drive device that drives driven sprockets of left and right cylinders via a chain by independent driving sprockets.

[0007]

However, each of the conventional valve train drive devices described above has the following problems.
That is, in the valve drive device shown in FIG. 5,
Since the drive side sprockets b and c are provided at both left and right ends of the crankshaft a, there is a problem that the engine width becomes wide. In addition, even those disclosed in JP-A-1-163423 and JP-A-59-85405 have the disadvantage that the engine width cannot be narrowed. In that case, the left and right balance of the valve drive device is bad,
In addition, there may be a difference in cooling performance between the left and right sides of the engine.

Further, in the valve drive system disclosed in Japanese Patent Laid-Open No. 54-50718, since the left and right idle shafts are independent of each other, the drive related to the valve opening / closing timing during engine assembly is performed. This causes a problem that the side sprockets need to be individually aligned on the left and right sides of the engine.

The present invention has been made in order to solve the above-mentioned conventional problems. In a four-cycle engine having a plurality of valve train driving devices such as a V-type engine or a horizontally opposed engine, the engine width is reduced. An object of the present invention is to provide a four-cycle engine which can be set narrowly and requires only one alignment of the left and right drive side sprockets during engine assembly.

[0010]

The present invention has the following constitution in order to solve the above problems. According to a first aspect of the present invention, the motion of transmitting the rotation of the crankshaft of the overhead camshaft type engine from the drive side sprocket on the engine case side to the driven side sprocket for rotating the camshaft on the cylinder head side through the endless continuum. In a V-type or horizontally opposed four-cycle engine having a valve system drive device in each of the left and right cylinders, an idle shaft driven by the crankshaft is installed in the engine case substantially parallel to the crankshaft, and the left and right of the idle shaft are installed. A drive-side sprocket that drives the driven-side sprockets of the left and right cylinders is provided at each end of both shafts.
In the four-cycle engine, the valve train drive devices are arranged on both left and right sides of the engine.

According to a second aspect of the present invention, each of the left and right drive side sprockets is located at substantially the same position as the left and right journal portions of the crankshaft in the engine width direction. Is.

According to the present invention, since the drive side sprockets for driving the driven side sprockets of the left and right cylinders are provided at both left and right shaft ends of the idle shaft, the distance between the left and right drive side sprockets is reduced. Therefore, the engine width can be narrowed.

Further, since the left and right drive side sprockets are provided at both left and right end portions of one common idle shaft, the position adjustment of the left and right drive side sprockets related to the valve opening / closing timing is performed once at the time of engine assembly. You can decide with.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the fourth embodiment.
2 is a side view of the cycle engine, FIG. 2 is an explanatory view in which a part of the engine is cross-sectionally viewed, FIG. 3 is a vertical cross-sectional view taken along the crankshaft of the engine taken along the line III-III of FIG. 2, and FIG.
It is a figure explaining the camshaft which saw the cylinder head in a cross section along the line I-III.

The engine 1 is of the overhead camshaft type and is mounted on a V-type two-cylinder motorcycle, as shown in FIGS. Engine 1
In the front side cylinder (left side cylinder) 2F and the rear side cylinder (right side cylinder) 2R, two valve train drive devices 3F and 3R are provided separately. Reference numeral 1a1 is a chain chamber, 1a2 is a cylinder head cover, and 1b is an engine case. Further, in the present embodiment, the left side / right side means the left side / right side in the vehicle body width direction when facing the front of the vehicle.

In the valve train drive devices 3F and 3R, as shown in FIG. 3, the gear 4a attached to the right shaft end of the crankshaft 4 meshes with the first idle gear 5, and the first idle gear 5 is engaged. Of the idle gear 5 transmits the rotation of the crankshaft 4 to the first idle shaft (corresponding to the idle shaft according to the present invention) 6. As shown in FIGS. 2 and 3, the first idle shaft 6 is positioned parallel to and above the crankshaft 4 whose axis extends in the vehicle width direction, and together with this, the base of the V bank sandwiched between the cylinders 2F and 2R. Located near the edge. Also, the first idle shaft 6 is
It is rotatably supported by a pair of left and right bearings 15, 15 attached to the engine case 1b.

At the right and left ends of the first idle shaft 6, as shown in FIG. 3, a valve train drive device 3F,
3R drive-side sprockets 7F and 7R are provided, and the drive-side sprockets 7F and 7R are arranged at substantially the same position as the journal portion 4b of the crankshaft 4 in the width direction of the engine 1. The drive side sprocket 7F of the front side cylinder 2F is located inside the first idle gear 5 and is integrally formed with the first idle gear 5. This first idle gear 5 and drive side sprocket 7
The product integrated with F is the key 16 on the first idle shaft 6.
It is fixed in the rotation direction via the nut and is fixed in the axial direction by the nut 17 with the left side surface in contact with the right bearing 15. On the other hand, the drive side sprocket 7R of the rear cylinder 2R is located near the left side of the left bearing 15 and is integrally formed at the left shaft end of the crankshaft 4.
In this way, the drive side sprocket 7F located on the right side
Corresponds to the front side cylinder 2F located on the left side, and the drive side sprocket 7R located on the left side corresponds to the rear side cylinder 2R located on the right side.

Further, the drive side sprocket 7F on the right side
Drives the driven side sprocket 10F (see FIG. 4) via the chain 8F passing through the cam chain chamber 1a1 on the right side wall of the left cylinder 2F, as shown in FIG. As shown in FIG. 4, the driven side sprocket 10F is integrated with the second idle gear 11F in the rotational direction and is pivotally supported by the second idle shaft 12F. The camshaft 13F is rotationally driven by meshing with a drive gear 14F of the camshaft 13F. The left drive side sprocket 7R is, as shown in FIG. 3, a driven side sprocket (not shown) of the right cylinder 2R via a chain 8R passing through a cam chain chamber 1a1 passing through the left side wall of the right cylinder 2R. This driven-side sprocket is also driven by the camshaft 13R (using a second idle gear, a second idle shaft, and a drive gear (not shown) as transmission means, as in the case of the front cylinder 2F. (See Fig. 2)
In this case, the second idle gear of the rear cylinder 2R and the like are arranged on the left side of the rear cylinder 2R.

According to the present embodiment having the above-mentioned structure, since the drive side sprockets 7R and 7F are provided at both left and right ends of the first idle shaft 6, the space between the left and right drive side sprockets 7R and 7F is set. It is possible to reduce the distance.

Further, in this embodiment, the cam chain chamber 1a1 is provided on the right side wall for the left cylinder 2F and on the left side wall for the right cylinder 2R, so that the left and right drive side sprockets 7R, 7F are provided. Since the driven side sprockets of the cylinders on the opposite side to the respective installation sides are made to correspond to each other, the driving side sprockets 7R and 7F are provided at the same positions as the journal portion 4b of the crankshaft 4 and the left and right driving side sprockets 7R and 7F are provided. The distance between them can be made even narrower, and the engine width can be made as narrow as possible.

Further, the left and right drive side sprockets 7R, 7
Since F is provided at both left and right ends of the common first idle shaft 6, it is possible to determine the position alignment of the drive side sprockets 7R, 7F related to the valve opening / closing timing at once. .

The present embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment. For example, in the present embodiment, the chain drive valve system drive device using the drive-side and driven-side sprockets and the chain has been described, but the present invention is not limited to this, and a drive employing an endless continuous body such as a belt is used. It can also be applied to an engine having a valve system driving device. Also, the present invention
Not only the V-type engine but also the horizontally opposed engine can obtain the same effects as those of the V-type engine described in the embodiment.

[0023]

As described above, according to the present invention, in a four-cycle engine having a plurality of valve train driving devices such as a V-type engine or a horizontally opposed engine, the engine width can be set narrow, and Positioning of the left and right drive side sprockets can be determined at once when the engine is assembled.

[Brief description of drawings]

FIG. 1 is a side view of a 4-cycle engine according to the present embodiment.

FIG. 2 is an explanatory view showing a cross-section of a part of the engine.

3 is a vertical cross-sectional view taken along the crankshaft of the engine taken along the line III-III in FIG.

FIG. 4 is a view for explaining a camshaft, which is a sectional view of a cylinder head, taken along the line III-III in FIG.

FIG. 5 is a perspective view of a valve train drive device in a conventional 4-cycle engine.

[Explanation of symbols]

1 engine 1b engine case 2F, 2R front side (left side) cylinder, rear side (right side) cylinder 3F, 3R front side cylinder, rear side valve operating system drive device 4 crankshaft 4b journal part 6 first idle Shaft (corresponding to idle shaft) 7F, 7R Drive side sprockets of front side cylinder and rear side cylinder 8F, 8R Chain (an example of an endless continuous body) 10F Driven side sprockets of front side cylinder 11F Second side of front side cylinder Idle gear 13F Camshaft of front cylinder 13R Camshaft of rear cylinder 14F Drive gear of front cylinder

Claims (2)

[Claims] 1. A valve train drive for transmitting rotation of a crankshaft of an overhead camshaft type engine from a drive side sprocket on an engine case side to a driven side sprocket for rotating a camshaft on a cylinder head side through an endless continuous body. In a V-type or horizontally opposed four-cycle engine having a device for each of left and right cylinders, an idle shaft driven by the crankshaft is installed in the engine case substantially parallel to the crankshaft, and left and right shaft ends of the idle shaft are installed. A four-cycle engine characterized in that a drive side sprocket for driving the driven side sprockets of the left and right cylinders is provided in the part, and the valve train drive device is arranged on both left and right sides of the engine. 2. The four-cycle engine according to claim 1, wherein each of the left and right drive side sprockets is located at substantially the same position as the left and right journal portions of the crankshaft in the engine width direction.