JPS59180017A - Cam bearing structure of overhead valve type internal-combustion engine - Google Patents

Abstract

PURPOSE:To make a cylinder head small-sized and lightweight, by arranging cam shafts for driving suction and exhaust valves at positions more inside than bolt attaching holes for securing a cylinder head and in upper part of the cylinder head, and journaling the cam shafts by a half splitted bearing. CONSTITUTION:The cam shafts 12, 13 for opening and closing the suction and exhaust valves 10, 11 are arranged on the upper ends of valve levers 10a, 11a of the valves 10, 11. The cam shafts 12, 13 are situated in upper part of the cylinder head 2 and inside more than the bolt attaching holes 6 and are arranged in parallel with the arrangement of the cylinders 4. The shafts 12, 13 are journaled by the half splitted bearing 14 at a position between the shafts 12, 13 and the opposite ends of the cylinders 4, 4. The lower bearing section 14b of the bearing 14 is arranged integrally with the cylinder head 2 while the upper bearing section 14a thereof is fixed by using opposite bolts 15 positioned inside more than the bolt attaching holes 6 and to be offset to the arrangement of the cylinders 4 and a center bolt 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam bearing structure for an overhead valve type internal combustion engine.

Some overhead valve type internal combustion engines have multi-valve intake and exhaust valves, and two (1) camshafts, one for driving the intake valves and the other for driving the exhaust valves, are arranged above the cylinder head. However, in this type of overhead valve type internal combustion engine, there is a problem in that the shape of the cylinder head becomes large because two camshafts are accommodated in the cylinder head.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a cam bearing structure for an overhead valve type internal combustion engine that allows the cylinder head to be made smaller and the weight to be reduced due to the smaller size.

The present invention achieves the above object in an overhead valve type internal combustion engine in which a plurality of cylinders are arranged in a row and each cylinder is provided with three or more intake and exhaust valves. A camshaft is arranged above the cylinder head inside the bolt mounting hole for fixing the cylinder head,
Pivotally supported by half-split bearings at positions corresponding between adjacent cylinders, with both ends of the upper bearing portions of the half-split bearings being offset inward from the bolt mounting holes and in the cylinder arrangement direction. There are patents that are characterized in that they are fixed using fixed fixtures.

The present invention will be explained below with reference to embodiments shown in the drawings.

1 to 3 show an embodiment of the present invention applied to a diesel engine, in which 1 is a cylinder body, 2 is a cylinder part 01 fixed to the upper part of the cylinder body 1, and 3 is a cylinder head part 2. It is a head cover fixed in two parts. Four cylinders 4 are provided in a row in the cylinder body 1, and a piston 5 is fitted into each cylinder 4 so as to be able to reciprocate. On both sides of the cylinder head 2, both ends in the elongated direction,
At a position corresponding to between the adjacent cylinders 4, 4,
A plurality of bolt mounting holes 6 are provided, each penetrating in the vertical direction. The cylinder nffol+2 is fixed to the cylinder body 1 with a bolt 7 through the bolt mounting hole 6.

Further, on both sides of the cylinder marking portion 2, an intake pipe 8.8 and an exhaust pipe 9, which are branched into two for each cylinder 4, are provided. The combustion chamber 4a in the upper part of the cylinder 4 has the above-mentioned intake pipe 8.
An intake (3) valve 10, 10 is provided corresponding to 8, and an exhaust valve 11 is provided corresponding to the exhaust pipe 9 shown in -1-. Valve rod 1 of intake valve 10
0a and the valve lever lea of the exhaust valve 11 are parallel to the axial direction of the cylinder 4 and are provided to slide vertically in the cylinder mark portion 2. 20 is a fuel injection nozzle, and 21 is a preheating plug.

The upper end of the valve rod 10a of the intake valve 10 and the valve rod 1 of the exhaust valve 11
A camshaft 12 for driving the intake valve 10 to open and close, and a camshaft 3 for driving the exhaust valve II to open and close are provided at the upper end of the camshaft 1a.

The two camshafts 12 and 13 are arranged above the cylinder head 2, inside the bolt mounting holes 6, and parallel to the arrangement direction of the plurality of cylinders 4. Bearings 14 each having a half-split configuration are located at positions corresponding to both ends thereof and between the cylinders 4, 4 adjacent to each other.
It is pivoted by.

The half-split bearing 14 is the upper bearing! Jli I 4 a
and the bearing part +4b on the lower side, respectively. The lower bearing part 14b is integrated with the cylinder head 2, and the camshaft 12゜13 is placed on it, and the upper bearing part 14a is covered with the upper bearing part 14a.
at both ends and the center, respectively, with bolts 15.
They are fixed together by 15 and 16. Bolts 15.15 at both ends connect the cylinder bent portion 2 to the cylinder body 1.
The position is located inside the bolt mounting hole 6 for the bolt 7 to be fixed to the cylinder, and is offset in the direction in which the plurality of cylinders are arranged.With this configuration, the entire half-split bearing 14 can be mounted with bolts on both sides in the width direction. It is housed inside the holes 6, 6.

On one shaft end of the camshaft 12.13 which is supported as described above, there are gears 17, 18 that mesh with each other.
, 18a, and a pulley IJ 19 is fixed to the other shaft end of the camshaft 12.
Power is input from a crankshaft (not shown) via the crankshaft.

FIG. 4 shows another embodiment.

(5) In this embodiment, the − side bearing portion 14 of the half-split bearing 14 is
A is fixed by two bolts 15 and 15 at each end, and a total of five bolts including the center pole 1-16. Further, gears 17.18 provided at the shaft ends of the camshafts 12.13 respectively
is formed integrally with.

In this embodiment as well, the pole 1-15.15 is located inside the bolt hole 6 for fixing the cylinder head, and is offset in the direction in which the plurality of cylinders are arranged.

The devices of each of the embodiments described above are overhead valve type internal combustion engines in which the intake and exhaust valves have a multi-valve configuration.
la is provided to be substantially perpendicular to the cylinder head 2, and in this configuration, the two camshafts 12, 13 are arranged above the cylinder head and inside the port I/mounting hole 6. There is. With this arrangement, protrusion outward from the bolt mounting hole 6 is suppressed, and the cylinder head 2 is made narrower and smaller 6). Also, connect the camshafts 12 and 1.3 like this]
- Even if they are arranged inside the mounting hole 6, if the half-split bearing 14 that pivotally supports them is wide, it will not be possible to make the entire cylinder head narrow; however, with the above-mentioned device, This can be achieved by fixing both ends of the one-part side bearing portion 14a of the half-split bearing 14 with bolts 15 located inside the bolt mounting hole 6 and offset in the direction in which the cylinders are arranged. ing.

Therefore, with the two-unit device, the cylinder head 2 can be made narrower and smaller, and the weight of the whole can be reduced accordingly.

Incidentally, although the above-mentioned embodiments have been described in the case of a diesel engine, the present invention is also applicable to the case of a gasoline engine. Although a three-valve type with two intake valves and 1111 exhaust valves per cylinder has been described, the present invention is also applicable to a four-valve type with two intake valves and two or more exhaust valves each, or a four-valve type with two or more intake valves and two or more exhaust valves. It is also applicable to the above cases.

(7) As described above, the present invention provides an overhead valve type internal combustion engine in which a plurality of cylinders are arranged in a row and each cylinder is provided with three or more intake and exhaust valves. The camshaft that drives the exhaust valve is arranged on the cylinder head side, which is inside the port I mounting hole for fixing the cylinder head, and a half-split type is installed at the corresponding position between the adjacent cylinders. The shaft is supported by a bearing, and both ends of the upper bearing part of the half-split bearing are fixed by a fixture that is located inside the port I/mounting hole and offset in the cylinder arrangement direction. , the two camshafts and their bearings are arranged inside the bolt mounting hole, so there is no protrusion, and the cylinder head is made narrower and more compact. Moreover, along with the size reduction, the weight is also reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a diesel engine according to an embodiment of the present invention with the head cover removed. FIG.
-B sectional view, FIG. 3 is a sectional view taken along line AA in FIG. 1, and FIG. 4 is a plan view showing the engine (8) according to another embodiment with the head cover removed. 1...Cylinder body, 2...Cylinder head, 4...
Cylinder, 6...Bolt mounting hole, 7.15...Bolt, 10...Intake valve, 11...Exhaust valve, 12.13
...Camshaft, 14..Half-split bearing, 14a..Upper side bearing part. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Teru Patent Attorney Kazuhiko Saishita (9) Figure 2 Section 3

Claims (1)

[Claims] In an overhead valve type internal f/A engine in which a plurality of cylinders are arranged in a row and each cylinder is provided with three or more intake and exhaust valves, a camshaft that drives the intake valves and a camshaft that drives the exhaust valves are It is arranged above the cylinder head inside the bolt mounting hole for fixing the cylinder head, and is supported by a half-split bearing at a position corresponding to between adjacent cylinders, and the upper side of the half-split bearing A cam bearing structure for an overhead valve type internal combustion engine, in which both ends of the bearing part are fixed by fixtures that are located inside the bolt mounting hole and offset in the cylinder arrangement direction.