JPH0217128Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a camshaft mounting structure for an internal combustion engine, and especially for an overhead camshaft type engine, a single camshaft can be used to install two intake valves and an exhaust valve.
The present invention relates to a camshaft mounting structure in a valve operating mechanism of a multi-valve internal combustion engine that operates more than one valve.

In general, a valve mechanism consists of a camshaft that is held on a cylinder head by a cam holder and is rotatably mounted and supported by two mounting bolts placed on both sides of the cylinder head, and fixed with a locking bolt. It consists of a locking shaft, a locking arm fitted into the locking shaft, and the like.

By the way, the multi-valve type valve mechanism described above has many driven valves, and since these are driven by a single camshaft, the load on the camshaft journal increases, and furthermore, the directionality of the load is opposite to the mounting direction of the cam holder. Particularly when the structure is such that force is applied, it is necessary to strengthen the support of the camshaft journal as a countermeasure. This requirement is also made more necessary in multi-cylinder internal combustion engines.

In addition to the above structure, a valve train generally has a cam holder mounting bolt, a locking shaft rotation locking bolt, a cylinder head mounting bolt, etc., which requires a large number of parts and assembly man-hours, and also requires sufficient space for each installation. However, there are problems with the overall size, complexity, and weight increase.

The present invention was devised in view of the above circumstances, and its purpose is to strengthen and support the installation of the camshaft in order to cope with the increase in load, while tightening one of the mounting bolts of the cam holder to the shaft. To provide a camshaft mounting structure for a multi-valve internal combustion engine, which can be used also as a locking bolt, simplify assembly, and also enable small assembly of the camshaft and cam holder to improve assembly work efficiency.

In order to solve the above problems and achieve the object, the present invention provides a camshaft mounting structure for a multi-valve internal combustion engine in which a camshaft 12 is rotatably mounted and supported on a cylinder head 4 via a cam case 11 and a cam holder 13. A mounting bolt 24 at one end of the tightening portion of the cam holder 13, a mounting bolt 23 penetrating through at least a portion of the rocker shaft 14 at the other end of the tightening portion, and a mounting bolt 23 at the other end of the cam holder 13.
Mounting bolt 25 closer to the camshaft 12
and the mounting bolt 25 is attached to the cam case 1.
1, and both mounting bolts 23,
24 is screwed onto the cylinder head 4 through the cam case 11 to attach the camshaft 12.

A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

1 is a plan view of the cam case and cylinder head with the head cover removed, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line -- in FIG.

1 is a cylinder block, 2 is a cylinder, 3 is a piston, and 4 is a cylinder head.A spark plug 5 is attached to the cylinder head 4, and on one side of the axis of the spark plug 5 is an intake passage 6 and an intake air between the combustion chamber. An intake valve 7 that opens and closes the valve port is provided, and an exhaust passage 8 and an exhaust valve 9 that opens and closes the exhaust valve port of the combustion chamber are provided on the other side.In the embodiment, each cylinder has two intake valves 7, 7 and two Exhaust valves 9, 9 are provided.

A cam case 11 is mounted on the cylinder head 4, and a camshaft 12 is disposed obliquely above the intake valve 7, with its camshaft journal being supported by being sandwiched between a cam holder 13 and a journal receiving surface of the cam case 11. Ru.

Rocker shafts 14 and 15 are inserted and supported in the cam case 11 parallel to the camshaft 13 on the intake valve 7 side and the exhaust valve 9 side, respectively.

A cam follower 16 is rotatably attached to the rocker shaft 14 on the intake valve 7 side, and a rocker arm 17 is rotatably attached to the rocker shaft 15 on the exhaust valve side.
A push rod 18 is provided with both ends engaged with the push rod 7.

The intake valve 7 is provided with a cam follower 1 whose one end is pivoted to the cylinder head 4 side below the camshaft 12.
The exhaust valve 9 follows the cam portion 12a of the camshaft 12 via the cam follower 16, the push rod 18, and the rocker arm 17 to open and close the exhaust valve 9.
Follow b to open and close.

A plurality of cam holders 13 are provided at intervals in the length direction of the camshaft 12.
The cam holder 130 disposed at the end of the camshaft 12 has two mounting bolts 2 which are inserted through the cam case 11 on both sides of the camshaft 12 and screwed into the cylinder head 4.
1 and 21 are tightened and fixed to the cylinder head 4 together with the cam case 11.

A cam holder 131 disposed in the middle of the camshaft 12 has one side attached to the rocker shaft 14.
A mounting bolt 23 extends upward 22, inserts the cam case 11 from the extending portion 22, and screws it onto the cylinder head 4;
The cylinder head 4 is attached to the cam case 11 with the mounting bolt 24, which is inserted through the cam case 11 and screwed onto the cylinder head 4.
Tighten and secure.

A mounting bolt 23 attached to the extending portion 22 passes through the rocker shaft 14, and prevents the rocker shaft 14 from rotating.

Furthermore, a mounting bolt 23 is attached to the extension portion 22.
A mounting bolt 25 is inserted between the camshaft 12 and the cam case 11, and the mounting bolt 25 connects the cam holder 131 and the cam case 1.
Tighten and secure 1.

A portion of the cam case 11 opposite to the camshaft 12 is tightened and fixed to the cylinder head 4 by mounting bolts 26 and 27, and the mounting bolt 26 passes through the rocker shaft 15 to prevent the rocker shaft 15 from rotating.

A head cover 28 is attached on the cam case 11, and the cam holder 13, camshaft 12, and rocker shaft 1 are secured by the head cover 28.
4, 15, cam follower 16, rock arm 17
Cover etc.

This embodiment is constructed as described above, and the mounting bolts 2
Since the mounting bolt 25 for tightening the cam holder 13 and the cam case 11 is provided between the camshaft 12 and the camshaft 12, the mounting strength of the cam holder 13 can be further increased. The camshaft 12 can be stably supported against an increase in load and its direction.

In addition, since the mounting bolt 23 of the cam holder 13 prevents the locking shaft 14 from rotating, the locking shaft 14 can be stopped from rotating at the same time as the cam holder 13 is installed, which simplifies the assembly of the engine valve mechanism. Production efficiency can be increased.

Furthermore, the number of parts can be reduced by the above-mentioned commonality, and there is no need to separately secure a mounting space for the rotation prevention member of the rocker shaft 14 on the cylinder head 4, thereby increasing space efficiency on the cylinder head 4. Can be done.

Also, the rocker shaft 1 is placed on the cylinder head 4.
Since the cam case 11 supporting the cylinder head 4, 15, etc. is provided, and the cam holder 13 is attached to the cam case 11, if the cam holder 13 is attached to the cam case 11 with the mounting bolt 25, it can be separated from the cylinder head 4, i.e. Mounting bolt 2
3, 24, 26, and 27 before installing the cam case 11 to the cylinder head 4, the camshaft 12,
Lotsuka shaft 14, 15, cam follower 16,
The main parts of the valve mechanism, such as the rocker arm 17, can be assembled on the cam case 11 in advance, and the efficiency of the assembly work can be greatly improved.

As is clear from the above explanation, according to the present invention,
In addition to strengthening and supporting the installation of the camshaft,
The cam holder's mounting bolt can also be used as a rotation prevention member for the rocker shaft, simplifying assembly work and increasing space efficiency on the cylinder head. Since the camshaft is assembled into small parts using the cam holder and then attached to the cylinder head, the assembly work efficiency can be greatly improved.

[Brief explanation of the drawing]

1 is a plan view of the cam case and cylinder head portion with the head cover removed, FIG. 2 is a schematic cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along the line -- in FIG. In the drawing, 1 is a cylinder block, 4 is a cylinder head, 7 is an intake valve, 9 is an exhaust valve, 11 is a cam case, 12 is a camshaft, 13 is a cam holder, 14, 15 is a rocker shaft, 23, 24,
25 is a mounting bolt.

Claims (1)

[Claims for Utility Model Registration] A camshaft mounting structure for a multi-valve internal combustion engine in which a camshaft 12 is rotatably mounted and supported on a cylinder head 4 via a cam case 11 and a cam holder 13, which provides for tightening the cam holder 13. A mounting bolt 24 at one end of the tightening section, a mounting bolt 23 passing through at least a part of the locking shaft 14 at the other end of the tightening section, and a mounting bolt 23 extending from the mounting bolt 23 at the other end of the tightening section to the camshaft 12.
A mounting bolt 25 is provided at the offset portion, and the mounting bolt 25 is screwed onto the cam case 11, and both mounting bolts 23 and 24 are screwed onto the cylinder head 4 via the cam case 11.
A camshaft mounting structure for a multi-valve internal combustion engine, characterized in that a camshaft 12 is mounted.