JP5310643B2 - cylinder head - Google Patents

Description

  The present invention relates to a cylinder head having a support structure close to a head bolt boss.

 An example of an engine cylinder head structure is shown in Patent Document 1. In Patent Document 1, a head bolt for assembling a cinder head to a cylinder block is disposed at a substantially intermediate position between adjacent cylinders in order to receive the explosion stress of the cylinder evenly and stably fix the cylinder head to the cylinder block. In order to facilitate the tightening operation of the head bolt, a gap is provided in the camshaft support wall (lateral wall portion), and the cam journal is disposed obliquely above and outside the head bolt (paragraph [0048]). The cam journal was not arranged on the axis of the head bolt.

JP 2004-204706 A

The present invention has been made in view of the above Patent Document 1, and an object thereof is to provide a compact cylinder head by arranging a cam journal on the axis of a head bolt.
Another object of the present invention is to provide a column supporting a camshaft support (lateral wall) at a position close to a head bolt boss through which the head bolt penetrates, and to supply oil to the cam journal to the column. The object is to provide a cylinder head which is provided with a path to achieve further compactness.

A cylinder head according to claim 1 of the present invention for solving the above-mentioned problems forms a base portion attached to a cylinder block by a head bolt, and a drive space for valve operating means extending from an edge of the base portion to the opposite side of the cylinder block. A peripheral wall portion, a vertical wall portion that divides the drive space into an intake side and an exhaust side and is connected to the peripheral wall portion, and a cam journal of a camshaft is positioned on an axis of the head bolt, and is separated from the base portion A horizontal wall portion spanned between the peripheral wall portion and the vertical wall portion, a support column connecting the base portion and the horizontal wall portion in the vicinity of the bolt, and an oil gallery formed on the base portion to the cam journal through the support column and a fluid passage for supplying the oil, the oil passage, the formed parallel to the axis of the head bolt, wherein the lateral wall portion before in cooperation with the lateral wall across the camshaft It is formed bolt boss for mounting the cam cap which forms a cam journal, the oil passage from the line connecting the said head bolt bolt boss, characterized by axial displacement of the camshaft.

 The cylinder head according to claim 1 of the present invention is a cylinder head in which the head bolt and the cam journal are arranged at overlapping positions to make the cylinder head compact, and supports the horizontal wall portion on which the cam journal is formed. Since an oil passage for supplying oil to the cam journal is formed, further downsizing can be achieved.

 According to the cylinder head of the present invention, the oil passage can be brought close to the head bolt, that is, the cam journal on the bolt axis by making the oil passage parallel to the bolt axis.

 According to the cylinder head of the present invention, the rigidity is increased by securing the distance between the bolt and the oil passage.

It is a perspective view of a cylinder head concerning Example 1 of the present invention. It is a top view of the cylinder head concerning Example 1 of the present invention. FIG. 3A is a plan view showing an arrangement example 2 in which the column is offset from the center line between the intake side head bolt boss and the exhaust side head bolt boss, and FIG. 3B is an intake side head bolt boss. And the top view which shows the example 1 of arrangement | positioning which has arrange | positioned the support | pillar on the centerline between exhaust side head bolt bosses, FIG.3 (c) is the sectional view on the AA line in FIG.3 (b). 4A is a perspective view showing an arrangement example 2 in which a support column is offset from the center line between the intake side head bolt boss and the exhaust side head bolt boss, and FIG. 4B is an intake side head bolt boss. It is a perspective view which shows the example 1 of arrangement | positioning which has arrange | positioned the support | pillar on the centerline between the exhaust side head bolt bosses.

 Hereinafter, modes for carrying out the present invention will be described based on examples.

 A cylinder head according to an embodiment of the present invention is shown in FIGS.

 As shown in FIG. 1, a cylinder head 20 is disposed on the cylinder block 10 via a seal member (not shown) such as a gasket.

 The cylinder head 20 has a bottom wall (base) 21 attached to the cylinder block 10 by a head bolt 30 and extends from the edge of the bottom wall 21 to the side opposite to the cylinder block 10 (upper side in the drawing). And a vertical wall portion 23 that divides the drive space into an intake side and an exhaust side and continues to the peripheral wall portion 22.

 A plurality of head bolt bosses 31 for inserting the head bolts 30 are formed on the bottom wall portion 21.

 The peripheral wall portion 22 includes a vertical peripheral wall portion 221 that is substantially along the direction in which the combustion chambers are lined up (hereinafter referred to as the front-rear direction), and a horizontal peripheral wall portion 222 that is generally along the direction across the direction in which the combustion chambers are lined up (hereinafter referred to as the width direction). And have.

 The vertical wall portion 23 is disposed substantially at the center in the width direction of the cylinder head 20 and extends along the front-rear direction. The vertical wall portion 23 is integrally formed with the bottom wall portion 21 and rises in the vertical direction, and both ends in the front-rear direction are integrally formed with the horizontal peripheral wall portion 222. That is, the bottom wall portion 21, the peripheral wall portion 22, and the vertical wall portion 23 are integrally formed.

 The cylinder head 20 is assembled with an intake camshaft 40 and an exhaust camshaft 50 that constitute a valve operating mechanism for opening and closing an intake valve (not shown) and an exhaust valve (not shown).

 The intake camshaft 40 is disposed on the intake side (left side in the figure) with the vertical wall portion 23 interposed therebetween, and the exhaust camshaft 50 is disposed on the exhaust side (right side in the figure).

 First, a structure for supporting the exhaust camshaft 50 will be described. On the exhaust side of the cylinder head 20, a plurality of exhaust side lateral walls 24 that support the exhaust camshaft 50 are arranged at equal intervals. The exhaust side lateral wall portion 24 is formed to extend over the vertical wall portion 23 and the longitudinal peripheral wall portion 221 disposed on the exhaust side, and extends in the width direction.

 The vicinity of both end portions of the exhaust side lateral wall portion 24 is formed integrally with the bottom wall portion 21, and other portions are separated from the bottom wall portion 21. That is, in the exhaust side lateral wall portion 24, a gap is formed between a portion other than both end portions and the upper end surface of the bottom wall portion 21.

 An exhaust camshaft support 24 a that supports the exhaust camshaft 50 is formed on the exhaust side lateral wall 24. The exhaust camshaft support 24a has a concave shape with a semicircular cross section. The exhaust camshaft support 24a is attached with a cam cap (not shown) having a semicircular cross section with the intake camshaft 40 interposed therebetween to form a cam journal. Two bolt holes 24 b and 24 b for attaching the cam cap are formed on the upper surface of the exhaust side lateral wall portion 24. The direction connecting these two bolt holes 24b, 24b and the head bolt boss 31 is parallel to the direction connecting the head bolt bosses 31, that is, the width direction.

Next, a support structure for the intake camshaft 40 will be described. On the intake side of the cylinder head 20, intake side lateral wall portions 25 that extend linearly along the width direction are arranged at equal intervals.
The intake side lateral wall portion 25 is formed to extend over the vertical wall portion 23 and the vertical peripheral wall portion 221 disposed on the intake side, and extends linearly in the width direction.

 The intake side lateral wall portion 25 has an intake camshaft support portion 25 a that supports the intake camshaft 40. The intake camshaft support 25a has a concave shape with a semicircular cross section. The intake camshaft support 25a is provided with a cam cap (not shown) having a semicircular cross section cut across the intake camshaft 50 to form a cam journal. Two bolt holes 25 b and 25 b for attaching the cam cap are formed on the upper surface of the intake side lateral wall portion 25. The direction connecting these two bolt holes 25b, 25b and the head bolt boss 31 is parallel to the direction connecting the head bolt bosses 31, that is, the width direction.

 A rocker arm mechanism is disposed between the vertical wall portion 23 and the vertical peripheral wall portion 221 on the intake side, but the rocker arm mechanism is omitted in the drawing.

 Next, a fixing structure between the cylinder block 10 and the cylinder head 20 will be specifically described. The cylinder head 20 is fixed to the cylinder block 10 with a head bolt 30. A plurality of head bolt bosses 31 through which the head bolt 30 penetrates are formed in the bottom wall portion 21.

 The head bolt bosses 31 arranged on the exhaust side are arranged one by one between the exhaust side lateral walls 24 adjacent in the front-rear direction. Therefore, a sufficient work space is ensured around the head bolt boss 31 such as inserting the head bolt 30 into the head bolt boss 31.

 The head bolt boss 31 disposed on the intake side is disposed directly below the intake camshaft support portion 25 a formed on the intake side lateral wall portion 25. That is, the intake camshaft support 25 a is positioned on the axis of the head bolt 30. Therefore, the head bolt 30 and the cam journal can be arranged at the overlapping position, and the cylinder head can be made compact as compared with Patent Document 1 in which the cam journal is arranged obliquely above and outside the head bolt.

 The intake camshaft support 25a formed on the intake side lateral wall 25 is formed wider in the front-rear direction than the portion other than the intake camshaft support 25a in the intake side lateral wall 25 when viewed from above. Yes. Further, an insertion hole 25c reaching the head bolt boss 31 is formed between both edge portions in the front-rear direction of the intake camshaft support portion 25a. Therefore, the head bolt boss 31 on the intake side is exposed so as to be accessible from above through the insertion hole 25c.

 The insertion hole 25c has such a size that a head bolt 30 and a tool used when assembling the head bolt 30 can enter. For this reason, a space for assembling the head bolt 30 is secured around the head bolt boss 31 on the intake side.

 The exhaust side lateral wall portion 24 and the intake side lateral wall portion 25 are formed together when the cylinder head 20 is formed by casting or the like. Therefore, the bottom wall portion 21, the vertical wall portion 23, and the peripheral wall portion are formed. 22 is integrated.

 Further, in the vicinity of the head bolt boss 31 disposed below the intake side lateral wall portion 25, although not hidden by the intake side lateral wall portion 25 and the like in FIGS. 1 and 2, the bottom wall portion 21 and the intake side lateral wall portion are not visible. 25 is erected. The support column 26 is a reinforcing material that supports the intake side lateral wall portion 25. The space between the support column 26 and the head bolt boss 31 is narrow due to restrictions due to the position of the intake camshaft 40. The cross section of the column 26 is oval.

An oil passage 27 for supplying oil (lubricating oil) from the oil gallery formed in the bottom wall portion 21 to the intake camshaft support portion 25 a is formed in the support column 26. The oil passage 27 is parallel to the axis of the head bolt 30. Accordingly, the oil passage 27 can be brought close to the intake camshaft support portion 25 a on the axis of the head bolt 30.
FIG. 3 and FIG. 4 show the positional relationship between the column 26 and the head bolt boss 31. In FIGS. 3 and 4, structures other than the column 26 and the head bolt boss 31 are drawn out.

FIG. 3B shows an arrangement example 1 in which the column 26 is arranged on the center line between the intake side head bolt boss 31 and the exhaust side head bolt boss 31. FIG.3 (c) is the sectional view on the AA line in FIG.3 (b).
On the other hand, FIG. 3A shows an arrangement example 2 in which the support columns 26 are arranged offset by an angle φ from the center line between the intake-side head bolt boss 31 and the exhaust-side head bolt boss 31.

However, in the arrangement example 2 shown in FIG. 3A, the column 26 needs to connect the bottom wall portion 21 and the intake side lateral wall portion 25, so that the intake side head bolt boss 31 and the exhaust side head bolt boss 31 It was rotated so that a part remained on the center line between.
Further, the distance C in the width direction between the center of the intake-side head bolt boss 31 and the oil passage 27 in the column 26 is set to be equal to or less than the oil line installation limit. The oil line installation limit means a limit at which the oil passage 27 can be connected to the oil gallery provided on the bottom wall portion 21.

 The distance C cannot be made too long in order to make it less than the oil line installation limit. However, as the distance between the head bolt boss 31 and the column 26 becomes shorter, the distance between the head bolt boss 31 and the base of the column 26 becomes smaller. The curved surface has a problem that the radius of curvature is small and stress concentration is likely to occur.

Here, in the arrangement example 1 shown in FIG. 3B, the distance between the center of the intake-side head bolt boss 31 and the outer surface of the column 26 is a, whereas the arrangement example shown in FIG. 2, the distance b between the center of the intake-side head bolt boss 31 and the outer surface of the column 26 is as shown in the following equation.
b = a / cosφ
b−a = a (1 / cosφ−1)
That is, in the arrangement example 2 shown in FIG. 3A, compared to the arrangement example 1 shown in FIG. 3B, the distance between the center of the intake-side head bolt boss 31 and the outer surface of the column 26 is a (1 / It can be increased by cosφ-1).

 In general, a curved surface (so-called R is attached) is provided between the head bolt boss 31 and the base of the support column 26 in order to avoid stress concentration, but the center of the head bolt boss 31 and the support column 26 are provided. When the distance between the outer surfaces is small, the curved surface between the head bolt boss 31 and the base of the column 26 has a small radius of curvature, as shown in FIG. When the distance between the outer surfaces of the columns 26 is large, as shown in FIG. 4A, the curved surface between the head bolt boss 31 and the base of the column 26 has an advantage that the radius of curvature is large and stress concentration is less likely to occur. There is.

In addition, the generation of the axial force of the head bolt 30 causes the head bolt boss 31 to fall outward while sinking as shown by a one-dot chain gland in FIG. When the tensile stress is generated at the base of the column 26, the head bolt boss 31 on the opposite side also falls down in the same manner.
Therefore, in the arrangement example 1 shown in FIG. 3B, the column 26 on the center line between the head bolt bosses 31 is pulled between the two bosses 31 and the tensile stress becomes larger, whereas in FIG. In the arrangement example 2 shown in (a), the effect of pulling by the boss on the opposite side can be reduced by displacing (offset) the closest part of the column 26 in the axial direction of the camshaft by a × tanφ. .

As described above, in the arrangement example 1 shown in FIG. 3B and the arrangement example 2 shown in FIG. 3A, the oil passage 27 is formed in the support column 26 that supports the intake side lateral wall portion 25. Further downsizing can be achieved as compared with the case where a separate structure having a path is provided.
Further, because of the restriction due to the position of the intake camshaft 40, the column 26 must be provided close to the head bolt boss 31, so the distance between the column 26 and the head bolt boss 31 could not be set wide. In the arrangement example 2 shown in FIG. 3 (a), the column 26 adjacent to the head bolt boss 31 is offset from the center line between the head bolts.
(1) Reduction of stress concentration at the base of the column (2) High cycle fatigue (metal fatigue due to high-frequency vibration caused by explosion in the cylinder) and improved life, and the effect of durability reliability can be obtained.

 The present invention can be widely used industrially as a cylinder head having a support structure close to a head bolt boss.

DESCRIPTION OF SYMBOLS 10 Cylinder block 20 Cylinder head 21 Bottom wall part 22 Peripheral wall part 221 Vertical peripheral wall part 222 Horizontal peripheral wall part 23 Vertical wall part 24 Exhaust horizontal wall part 25 Intake side wall part 26 Support | pillar 27 Oil path 30 Head bolt 31 Head bolt boss 40 Intake Camshaft 50 Exhaust camshaft

Claims (1)

A base attached to the cylinder block with a head bolt;
A peripheral wall portion extending from the edge of the base portion to the opposite side of the cylinder block to form a drive space of the valve operating means;
A vertical wall section that divides the drive space into an intake side and an exhaust side and is connected to the peripheral wall section;
A cam journal of a camshaft is located on the axis of the head bolt, and is spaced apart from the base, and a lateral wall portion spanned between the peripheral wall portion and the vertical wall portion;
A strut connecting the base and the lateral wall near the bolt;
An oil passage that supplies oil to the cam journal from the oil gallery formed in the base through the support column ;
The oil passage is formed in parallel with the axis of the head bolt,
A bolt boss for attaching a cam cap that forms the cam journal in cooperation with the lateral wall portion across the cam shaft is formed on the lateral wall portion,
The cylinder head according to claim 1, wherein the oil passage is displaced in an axial direction of the camshaft from a line connecting the head bolt and the bolt boss .

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