JPH06272613A - Cylinder fastening structure for engine - Google Patents

Abstract

PURPOSE:To miniaturize the shape of a cam cap, reduce its weight, and improve the freedom degree of arrangement of a part in relation to space between a cylinder head and a cylinder head cover for covering the cylinder head. CONSTITUTION:A cylinder head 4 is detachably fastened with a cylinder block 2 by a first bolt 9. The inserting hole 24 of a screw tool 25 for the first bolt 9 is provided on a cam cap 15 installed on a cylinder head 4. A cylinder head cover 26 for covering the cylinder head 4 is detachably fastened by a second bolt 29. A female screw 24a for allowing screwing of the second bolt 29 on the cam cap 15 is formed on the inner circumferential surface of the inserting hole 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder fastening structure in which an engine cylinder includes a cylinder block, a cylinder head, a cam cap attached to the cylinder head, and a cylinder head cover, which are fastened together.

[0002]

2. Description of the Related Art A cylinder of an engine mounted on a motorcycle or the like has hitherto been, for example, Japanese Patent Application No. 59-169905.
There is one disclosed in the publication.

According to this, the cylinder head is detachably fastened to the cylinder block by the first bolt, and the insertion hole for the screwdriver tool of the first bolt is formed through the cam cap attached to the cylinder head. Is
A cylinder head cover that covers the cylinder head is detachably fastened to the cam cap by the second bolt.

Then, after loosening the second bolt and removing the cylinder head cover from the cylinder head, inserting the tool into the insertion hole and loosening the first bolt, the cam cap is attached to the cylinder head. These can be detached from the cylinder block in an attachable and detachable manner, that is, with the cam shaft attached to the cylinder head.

[0005]

By the way, in the above-mentioned conventional structure, the insertion hole for the screwdriver of the first bolt and the female screw hole for screwing the second bolt are individually provided. Since the hole and the female screw hole are provided side by side on the cam cap, there is a problem that the cam cap becomes large and heavy.

The cam cap is housed in the space between the cylinder head and the cylinder head cover.
Since this space is narrow, if the cam cap is large as described above, there is also a problem that the space is greatly narrowed by that much, and the degree of freedom in disposing other components is reduced.

[0007]

SUMMARY OF THE INVENTION The present invention has been made paying attention to the above circumstances, and the cam cap has a small shape and
An object of the present invention is to reduce the weight and improve the degree of freedom in arranging components in the space between the cylinder head and the cylinder head cover that covers the cylinder head.

[0008]

To achieve the above object, the present invention is characterized in that a cylinder head is detachably fastened to a cylinder block by a first bolt and a cam cap attached to the cylinder head. In the case where a cylinder head cover that penetrates the insertion hole of the screwdriver tool for the first bolt and covers the same cylinder head is detachably fastened to the same cam cap by the second bolt, The point is that a female screw into which the second bolt is screwed is formed on the inner peripheral surface of the insertion hole.

[0009]

[Operation] The operation of the above configuration is as follows.

The cylinder head 4 is detachably fastened to the cylinder block 2 with the first bolt 9, and the cam cap 15 attached to the cylinder head 4 has a through hole 24 for a screwdriver tool 25 for the first bolt 9. And a cylinder head cover 26 that covers the cylinder head 4 of the same as above.
A female screw 24a for screwing the second bolt 29 into the cam cap 15 when it is detachably fastened is formed on the inner peripheral surface of the insertion hole 24.

For this reason, the insertion hole 24 of the screwdriver tool 25 for the first bolt 9 and the female screw hole conventionally provided for screwing the second bolt 29 into the cam cap 15 are combined into one hole. Will be done.

Moreover, the cam cap 15 is provided in the space 27 between the cylinder head 4 and the cylinder head cover 26 covering the cylinder head 4, and the space 27 is narrow, but as described above, the cam cap 15 is provided. The space 27 can be enlarged as much as the size can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral E in the drawing denotes a four-cycle engine mounted on a motorcycle or the like, and this engine E has four cylinders 1. Each of the cylinders 1 has the same shape and size, and has a cylinder hole 3 formed in the cylinder block 2, and the axis 3a of the cylinder hole 3 is oriented vertically. A cylinder head 4 is placed on the upper surface of the cylinder block 2, and the cylinder head 4 closes the upper end of the cylinder hole 3. 5 is a spark plug.

The cylinder head 4 is in the shape of a box that opens upward, and a bolt hole 8 is formed in the bottom plate 7 of the cylinder head 4 in parallel with the axis 3a. The cylinder head 4 is detachably fastened to the cylinder block 2 by a first bolt 9 which is inserted into the bolt hole 8 and screwed into the cylinder block 2.

A valve mechanism 10 is provided in the cylinder head 4.
Is provided. The valve mechanism 10 includes a cam shaft 11 whose shaft center is oriented laterally, and an oil passage 11a is formed in the cam shaft 11. Left and right ends of the cam shaft 11 (which means the direction toward FIG. 1) are supported by bearings 12, respectively, and are rotatable about their axes.

The bearing 12 has a cam receiving member 13 integrally formed on the inner wall of the cylinder head 4. On the upper surface of the cam receiving member 13, a semicircular groove 14 that opens upward
Is formed, and the lower half of the end portion of the cam shaft 11 is fitted into the semicircular groove 14.

The bearing 12 has a cam cap 15 which is fitted on the upper half of the cam shaft 11. The cam cap 15 is detachably attached to the cam receiving member 13 by a pair of front and rear fastening bolts 16, 16. It has been concluded.

A cam nose 18 of the cam shaft 11 is sucked through a tappet 19 and an exhaust valve is engaged with the cam. Further, the respective cam shafts 11, 11 of the cylinders 1, 1 located on the left and right are coaxially integrated, and the connecting portion of these left and right cam shafts 11, 11 is connected to the crank shaft of the engine E by the chain winding device 20. Is linked to.

The camshaft 11 rotates in conjunction with the crankshaft, and the intake and exhaust valves are opened and closed at a predetermined crank angle in conjunction with this.

The shaft center 9a of the first bolt 9 is a cam shaft 11.
The shaft center 9a of the first bolt 9 intersects with the cam cap 15 at substantially the center between the front and rear fastening bolts 16, 16. As above, insertion holes 23 and 24 are formed in the cam shaft 11 and the cam cap 15, respectively, on the shaft center 9a of the first bolt 9, and these insertion holes 23 and 24 are provided in the screwdriver tool 25 of the first bolt 9 described above. It is supposed to be inserted. In the above case, the cam shaft 11
Rotates around its axis 11b, so that when inserting the tool 25 into the insertion hole 23, the insertion hole 23 may be positioned on the axis 9a of the first bolt 9.

A cylinder head cover 26 is provided to cover the cylinder head 4 from above, and the valve operating mechanism 10 is provided.
Is the cylinder head 4 and the cylinder head cover 26.
It is stored in a space 27 surrounded by.

A bolt hole 28 is formed in the cylinder head cover 26 on the axis 9a of the first bolt 9. On the other hand, a female screw 24a is formed on the inner peripheral surface of the insertion hole 24.
Are formed. Then, the male screw 29a of the second bolt 29 inserted into the bolt hole 28 is replaced with the female screw 24a.
The cylinder head cover 26 is detachably fastened to the cam cap 15 by being screwed into
That is, it is fastened to the cylinder head 4 side.

In the above case, the tool 25 can also be inserted into the bolt hole 28. Further, the first bolt 9 includes the insertion holes 23, 24 and the bolt hole 28 including the head portion thereof.
Can pass through.

With the above structure, the insertion hole 24 and the female screw hole conventionally provided for screwing the male screw 29a of the second bolt 29 into the cam cap 15 are combined into one hole.

In this way, the cam cap 15 is miniaturized, and from this, the cam cap 1 is the same as above.
5 is made lighter.

The cam cap 15 is the cylinder head 4
Is provided in a space 27 between the cylinder head cover 26 and the cylinder head cover 26, which is narrow, and the space 27 is narrow.
The space 27 is enlarged.

In this way, the degree of freedom in arranging parts such as the cylinder discrimination sensor 31 in the space 27 is improved.

The cylinder discrimination sensor 31 is for detecting the state of the cylinder, and the detection signal determines the injection timing of the fuel injection valve, for example.

[0030]

According to the present invention, the cylinder head is detachably fastened to the cylinder block with the first bolt, and the cam cap attached to the cylinder head is provided with the insertion hole for the screwdriver tool of the first bolt. And a cylinder head cover for covering the cylinder head is detachably fastened to the cam cap with the second bolt, the female screw for screwing the second bolt into the cam cap is inserted into the insertion hole. It is formed on the peripheral surface.

Therefore, the insertion hole of the screwdriver for the first bolt and the female screw hole conventionally provided for screwing the second bolt into the cam cap are combined into one hole. .

Therefore, the cam cap can be made smaller than in the conventional case where the insertion hole and the female screw hole are provided side by side with respect to the cam cap, and from this, the cam cap can be lightened.

Moreover, the cam cap is provided in the space between the cylinder head and the cylinder head cover that covers it, and this space is narrow, but as described above, the cam cap can be made small, The space can be enlarged.

Therefore, there is an advantage that the degree of freedom in arranging parts such as the cylinder discrimination sensor in the space is improved.

[Brief description of drawings]

1 is a cross-sectional view taken along the line 1-1 of FIG.

FIG. 2 is a partially cutaway view of the entire plane of the engine.

3 is a sectional view taken along the line 3-3 of FIG.

[Explanation of symbols]

 1 Cylinder 2 Cylinder Block 4 Cylinder Head 9 First Bolt 10 Valve Mechanism 11 Cam Shaft 15 Cam Cap 23 Insertion Hole 24 Insertion Hole 24a Female Screw 25 Tool 26 Cylinder Head Cover 27 Space 29 Second Bolt 29a Male Screw E Engine

Claims (1)

[Claims] 1. A cylinder head is detachably fastened to a cylinder block with a first bolt, and a cam cap attached to the cylinder head is provided with a through hole for a screwdriver tool of the first bolt. In the cylinder fastening structure of the engine in which the cylinder head cover covering the same cylinder head is detachably fastened to the cam cap by the second bolt, the female screw for screwing the second bolt into the cam cap is provided on the inner peripheral surface of the insertion hole. Cylinder fastening structure of engine formed in.