JPS58150010A - Cam shaft support mechanism of dohc engine for motorcycle - Google Patents

Abstract

PURPOSE:To prevent projection of a cam shaft and heighten freedom of the driving posture of a crew by supporting a cam shaft, equipped with a cam to drive intake and exhaust valves, by means of a bearing interposed between two cams corresponding to two each intake and exhaust valves provided per cylinder. CONSTITUTION:Cam chambers 5 are formed respectively on both front and rear sides of the upper face of a cylinder head 4, and a cam chain chamber 6 is formed in the central part, while the upper part of each chamber 5, 6 is covered by means of a head cover 7. Four cylinders 8 in total are provided each on the left and the right interposing the cam chain chamber 6 between two cylinders, further each cylinder 8 is equipped with two intake valves 9 and exhaust valves 10. A cam shaft 14 is rotatably supported by means of a bearing 15, interposed between a pair of cams 13 provided in opposition to each other for each cylinder, and powered from a crankshaft through a sprocket 16 fixed in the cam chain chamber 6. Because of the above, lateral projection of the end of the cam shaft 14 from the outermost side cam 13 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camshaft support mechanism in a DOHC engine for a motorcycle.

The problem when mounting a DOHC 4-valve 4-cylinder engine on a motorcycle is that the part of the engine head that corresponds to the head cover protrudes laterally to the direction of travel, and that protruding part interferes with the rider's legs, making it difficult to adjust the riding position. This means that the degree of freedom will be restricted.

In other words, in the conventional DOHC 4-valve engine of a motorcycle, the bearing supporting the camshaft is placed at the position corresponding to the darkness of each cylinder and at the outside position of the outermost cylinder, so the outermost cylinder is located at the outermost position. This resulted in the camshaft extending in the horizontal direction by the distance of one of the receivers, which caused problems such as this extended portion interfering with the rider's legs.

An object of the present invention is to improve the performance of the conventional device as described above by one liter.
DOH for motorcycles that uses iliPI to increase the freedom of the rider's riding position.
The object of the present invention is to provide a support mechanism for a camshaft in a C engine.

A motorcycle according to the present invention that achieves the above object.

The camshaft support method in an HC engine consists of arranging multiple cylinders in a straight line in the lateral direction of the heavy body, and arranging two intake valves and two exhaust valves in each gem in the row direction. Or.

In the HC engine, the camshaft provided with the cam that drives the @air valve and the exhaust valve is attached to the @*W strawberry.
2 corresponding to the ＠蒐 valve and exhaust valve installed unevenly
It is characterized by being supported by a bearing interposed between the two cams.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments shown in the drawings.

! 1! Figures 1 and 2 are DOH according to an embodiment of the present invention.
This shows a motorcycle equipped with a C4 valve 4-cylinder engine. 1 is a DOHC 4-valve engine mounted in the center of the aircraft, and 2.3 are the front and rear wheels, respectively. Since the four cylinders in this engine 1 are arranged in series in the transverse direction with respect to the traveling direction, the second WJ
As shown in the figure, the side of the engine 1 protrudes considerably from the side of the fuselage, preventing it from interfering with rider M's legs.

FIG. 3 is a plan view showing only the right half of the DOHC 4-valve four-cylinder engine 1 with the upper head cover removed, with respect to the center line in the traveling direction indicated by arrow A. Since the left half has a symmetrical structure, it has approximately the same configuration as the right half. No. 4 Wj is a longitudinal sectional view of the cam chamber portion of the same engine.

In FIGS. 3 and 4, 4 is a cylinder head, and this cylinder head 4 is fixed to the lower cylinder block by a cylinder holding port 12. Cam chambers 5 are formed on both the front and rear sides of the upper surface of the cylinder head 4, and a cam chain chamber 6 is formed in the center. These cam chambers 5 and cam chien wealth 6
A head cover 7 is detachably attached to the upper part of the head cover 7. Reference numeral 8 denotes cylinders provided in the cylinder block below the cylinder head 4, and a total of four cylinders, two cylinders on each side, are provided on the left and right sides of the central cam chain chamber 6. Each cylinder 8 is provided with two intake valves 9.9 and one exhaust valve XO, and a large dot plug 11 is provided in the center of the cylinder.

The cam chambers 5.5 on both front and rear sides correspond to 8-ki 13H,
Valve tappets connected to the above-mentioned air valve 9.9 and exhaust valve 10.10 respectively face the valve tappet, and a cam 13 fixed to the camshaft 14 faces so as to correspond to each valve tappet. This camshaft 14 has a bearing 1 interposed between a pair of cams 13 and 13 installed opposite to each other on an 8-cylinder cylinder.
5, and is rotated by receiving power from the crankshaft via a sprocket 16 fixed to the cam chain chamber 6. F is a positioning projection fixed on the camshaft 14 and acts to stop the thrust of the camshaft.

In the above-mentioned NTS DOHC engine, the camshaft 14 is supported by an 8-inch intake valve 9.9 and an exhaust valve 1.
Since this is done by a bearing 15 interposed between a pair of cams 13 and 13 arranged oppositely at 0 and 10, respectively, the end of the cam shaft 14 is made to protrude further laterally outward than the outermost cam 13. This is no longer necessary, and the lateral protrusion of the cam chamber 5 is shortened accordingly. That is, in the conventional DOHC engine, the bearings supporting the camshaft 14 are each fixed at a 15° position indicated by a chain line.
ll, the camshaft became longer in the lateral direction, and the cam chamber 5 also extended to the side.
In the DOHC engine according to the present invention, such an overhang is eliminated and the lateral dimension is shortened overall.

Therefore, according to the DOHC engine of the present invention, the second
As shown in the figure, the lateral protrusion of the head cover 7 of the engine 1n portion is moved back toward the center from the conventional 7° position. As a result, as shown in Fig. 1, even if the rider M leans forward as indicated by 11!9, his feet will not interfere with the head cover 7, increasing the degree of freedom in his riding position. It begins to grow.

In addition, as mentioned above, in the conventional Do)Ic engine,
Since the camshaft bearings 15'' were provided corresponding to the outer positions between the adjacent eight cylinders and the outermost pages, these bearings 15' were arranged adjacent to the cylinder holding port 12, but For space reasons, the cylinder holding port 12
is housed inside the cam chamber 5 together with the bearing 15'. Therefore, when retightening the cylinder holding bolts 12, the head cover 7 must be removed each time, which is a hassle and reduces maintainability.

However, according to the DOHC engine of the above embodiment, since the bearing 15 and the cylinder holding bolt 12 are arranged at a position that is not adjacent to each other, it is easy to position the cylinder holding bolt 12 outside the head cover 7. As a result, the additional work can be carried out without removing the head cover 7.

As described above, the camshaft support mechanism in the DOHC engine for motorcycles according to the present invention has a plurality of holes linearly arranged in the lateral direction of the vehicle body, and a relaxation valve and an exhaustion valve for every eight cylinders. In a DOHC engine, two intake valves are arranged in each row in the direction of the rows of certificates, and two camshafts are provided for each @yIL111, and two camshafts are provided with cams for driving the intake valve and the exhaust valve. Since the two cams corresponding to the IIF air valves are supported by bearings interposed between the two cams, one end of the camshaft does not protrude further laterally than the outermost cam, which prevents the engine head. As a result, the rider's riding position is further increased in flexibility. .

[Brief explanation of drawings]

Fig. 1 is a side view of a motorcycle equipped with the DOHC engine of the present invention, Fig. 2 is a front view, and Fig. 3 is a plan view showing only the right half of the DOHC engine of the present invention with the head cover removed. 4 are four cross-sectional views of the same essential parts. 1. Engine, 5. Cam chamber, 8. Cylinder, 9. Intake valve, 1011.li
air valve, 13... cam 114... cam shaft, 15...
·bearing. Agent Patent Attorney No. 11 (Mi - Patent Attorney Ken Noguchi Teru Patent Attorney Kazuhiko Saishita Figure 2 Figure 4

Claims (1)

[Claims] In a DOHC engine, in which a plurality of cylinders are arranged linearly in the lateral direction of the vehicle body, and two intake valves and two exhaust valves are arranged in the cylinder row direction for every eight cylinders, the intake valves and the iI The camshaft with the cam that drives the valve is connected to the a-F! A camshaft support mt in a DOHC engine for a motorcycle, characterized in that it is supported by bearings interposed between two cams corresponding to the @air valves and the exhaust valves provided on two sides of the strawberry.
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