JP2000097103A - Oil removing structure of cylinder head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil removing structure of cylinder head in which the setting of a washer to a head bolt hole at the foremost end can be carried out simply, while realizing the reduction of the full length of an engine. SOLUTION: In an oil removing structure of a cylinder head 1, in which oil removing holes 8 from a valve system chamber 5 to the inside of a timing chain case are formed at the front side wall 2 of the cylinder head 1 in an internal combustion engine in which the timing chain case of a different body is connected to the front end surface of the cylinder head 1, oil removing holes 8 with the width allowable to insert the washer of a head bolt are formed fitting to head bolt holes 6 to insert the head bolts at the foremost end which fastens and fixes the cylinder head 1 to a cylinder block.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil dropping structure for discharging oil from a valve mechanism chamber of a cylinder head into a timing chain case, and more particularly to a structure in which a separate timing chain case is joined to a front end surface of a cylinder head. The present invention relates to a structure for removing oil from a cylinder head of an internal combustion engine.

[0002]

2. Description of the Related Art Generally, oil discharged into a valve mechanism chamber of a cylinder head in an internal combustion engine passes through an oil drop passage formed through a cylinder head and a cylinder block at a central portion and a rear portion of the cylinder head. At the front part, the oil is returned to the oil pan through the oil drop hole formed in the front wall of the cylinder head through the inside of the timing chain case.

[0003] In a conventional oil dropping structure at the front of a cylinder head, as shown in FIG. 3, substantially the entire width of a valve mechanism chamber 13 of a front wall 12 of a cylinder head 11 is focused on smooth oil outflow. In this range, three to five relatively narrow oil pits 14 are arranged so as to be substantially evenly distributed. Also, the bottom surface 13a of the valve mechanism chamber 13
Is a substantially flat surface, and each oil drop hole 14 is formed so that the lower edge thereof faces the bottom surface 13a.

[0004] In FIG. 3, reference numeral 15 denotes a cylinder head 11.
The head bolt holes 16, 17 at the forefront end for fastening and fixing to a cylinder block (not shown), and first and second bearing portions of camshafts on the intake and exhaust sides.

Japanese Patent Laid-Open Publication No. Hei 7-286508 discloses an internal combustion engine in which an upper portion of a timing chain case 22 is formed integrally with a cylinder head 21 as shown in FIG. Oil drop holes 2 are formed in the valve mechanism chamber 23 and the partition wall 24 of the timing chain case 22 by the projections formed in the core.
5 and the oil drop hole 25 is arranged at a position corresponding to the head bolt hole 26 so that the casting of the oil drop hole 25 is removed when the counterbore portion 27 of the head bolt hole 26 is processed. It has been disclosed.

[0006]

By the way, as shown in FIG. 3, three to five oil drop holes 14 having a relatively small width are used.
When the oil drop hole 14 is disposed at a position corresponding to the head bolt hole 15, the washer disposed in the counterbore portion 18 of the head bolt hole 15 at the foremost end is disposed from the upper opening of the cylinder head 11. There is a need to.
At this time, in order to reduce the overall length of the engine, the space between the first bearings 16 and 17 of the camshaft provided at the upper end of the front wall 12 of the cylinder head 11 and the valve shaft mounting cylinder of the first cylinder. If is made as small as possible, there is no space for placing the washer 18 with the washer pinched, so it is necessary to drop the washer from above. There is a problem that it is troublesome to dispose it, and it is necessary to start over many times, which is troublesome and deteriorates the assembling efficiency.

The above publication does not disclose any problems in the work of arranging the washers and means for solving the problems.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a cylinder head oil draining structure in which the washer can be easily arranged in a head bolt hole at the forefront end while shortening the entire engine length. And

[0009]

SUMMARY OF THE INVENTION The present invention relates to an internal combustion engine in which a separate timing chain case is joined to a front end face of a cylinder head. In the oil drop structure of the cylinder head with the oil drop hole formed in the cylinder head, the width of the head bolt washer can be inserted to fit the position of the head bolt hole for inserting the front end head bolt that fastens and fixes the cylinder head to the cylinder block. An oil drop hole is formed, and a washer is inserted through the oil drop hole formed in the front wall even if the space between the front wall and the valve shaft mounting cylinder portion of the first cylinder is narrow in order to reduce the overall length of the engine. As a result, the washer can be easily arranged in the counterbore part of the head bolt hole at the forefront end, and It can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cylinder head oil draining structure according to the present invention will be described below with reference to FIGS.

1 is a cylinder head, 2 is a front wall thereof, and a separate timing chain case (not shown) is joined to the front surface thereof. In the cylinder head 1, the space between the front wall 2 and the valve shaft mounting cylinder of the first cylinder is narrowed in order to reduce the overall length of the engine. Reference numerals 3 and 4 denote first bearing portions of the camshafts on the intake side and the exhaust side provided at the upper end of the front wall 2. 5 is a valve operating mechanism chamber formed at the top of the cylinder head 1 and having an open top surface, 5a is its bottom surface,
The bottom surface 5a is formed so that the central part is high in the width direction and the both sides are low, so that the oil discharged into the valve mechanism chamber 5 is collected on both sides. Reference numeral 6 denotes a head bolt hole at the forefront end formed to penetrate downward on both sides of the front end of the valve mechanism chamber 5. A plurality of similar head bolt holes are formed at appropriate intervals between the rear end of the cylinder head 1 and the cylinder head 1 is connected to the cylinder block (not shown) by head bolts (not shown) inserted into these head bolt holes. (Not shown). Reference numeral 7 denotes a counterbore formed at the upper end of the head bolt hole 6.

Reference numeral 8 denotes a pair of oil drop holes for discharging oil from a front portion of the valve mechanism chamber 5 into a timing chain case (not shown). The oil drop holes 8 face the head bolt holes 6 at the frontmost end of the front wall 2. Formed at the location. The oil drop hole 8 is formed with a width substantially equal to or larger than the diameter of the counterbore portion 7 so that a washer 9 of a head bolt can be inserted.

In FIG. 2, reference numeral 10 denotes a timing chain, and 10a denotes a cam shaft drive sprocket.

In the above construction, the oil discharged from the valve mechanism into the valve mechanism chamber 5 above the cylinder head 1 accumulates on the bottom surface 5a of the valve mechanism chamber 5 and is collected on both sides thereof. The oil at the center and the rear is returned to the oil pan through an oil drop passage (not shown) penetrating the cylinder head and the cylinder block, and the oil collected at both sides of the front is passed through the oil drop hole 8 to the timing chain. It is discharged into a case (not shown) and returned to the oil pan.

When assembling the cylinder head 1 on the cylinder block, the counterbore 7 at the upper end of the head bolt hole 6 at the forefront is passed through an oil drop hole 8 as shown by an arrow in FIG. A washer 9 is arranged, a washer is arranged in a counterbore of the other head bolt hole from the upper opening of the cylinder head 1, and a head bolt is inserted into each head bolt hole from the upper opening of the cylinder head 1 to form a cylinder block. And fixed.

As described above, in this embodiment, the washer 9 is inserted into the counterbore portion 7 of the head bolt hole 6 at the forefront end through the oil drop hole 8 formed in the front wall 2, so that the entire engine length is obtained. Even if the space between the front wall 2 and the valve shaft mounting cylinder portion of the first cylinder is narrowed to shorten the length, the washer can be easily arranged in the counterbore portion 7 of the head bolt hole 6 at the forefront end. As a result, assembly efficiency can be improved.

Since the front wall 2 is eliminated by the oil drop hole 8 in the machining range of the counterbore portion 7 of the head bolt hole 6 at the forefront end, the machining tool of the counterbore hole 7 is used in the valve mechanism chamber 5. It is sufficient to machine only the bottom surface 5a, and it is not necessary to machine the wall surface, so that the tool is not damaged and the machining cost can be reduced.

[0018]

According to the cylinder head oil draining structure of the present invention, the head bolt hole for inserting the frontmost head bolt for fastening and fixing the cylinder head to the cylinder block as described above is adjusted. An oil drop hole with a width that allows the washer to be inserted is formed, so even if the space between the front wall and the valve shaft mounting cylinder portion of the first cylinder is narrow in order to reduce the overall length of the engine, the oil drop hole formed in the front wall can be inserted through the oil drop hole. By inserting the washer, it is possible to easily arrange the washer in the counterbore portion of the head bolt hole at the forefront end, and it is possible to improve the assembly efficiency while shortening the overall engine length. In addition, since the front wall is eliminated by the oil drop hole when the counterbore portion is machined, no chipping or the like due to wall machining does not occur, and the machining cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a cylinder head in an embodiment of a cylinder head oil removing structure according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a front view of a cylinder head in a conventional cylinder head oil removing structure.

FIG. 4 is a partial vertical sectional side view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Front wall 5 Valve mechanism room 6 Head bolt hole 8 Oil drop hole 9 Washer

Claims (1)

[Claims] 1. An internal combustion engine in which a separate timing chain case is joined to a front end surface of a cylinder head. A cylinder having an oil drop hole formed in a front wall of the cylinder head from a valve mechanism chamber into the timing chain case. The head has an oil draining structure, and the oil draining hole has a width that allows the washer of the head bolt to be inserted in accordance with the position of the head bolt hole in which the frontmost head bolt for fastening and fixing the cylinder head to the cylinder block is inserted. The oil drain structure of the cylinder head.