JP6148103B2 - Cylinder head cover for internal combustion engine - Google Patents

Description

  The present invention relates to a cylinder head cover of an internal combustion engine made of synthetic resin, and more particularly to a seal of a cylinder head cover having an arch portion at one end in a longitudinal direction.

  As can be seen in Patent Document 1, a cylinder head cover of an internal combustion engine having an arch portion that rises upward at one end in a longitudinal direction is known. This arch is for avoiding interference between the front end of the cam shaft and the seal line of the cylinder head cover, for example, and has a shape along the upper edge of the metal front cover attached to the front end of the cylinder head. I am doing. The gasket that seals between the cylinder head cover and the cylinder head is formed continuously including the arch part described above. By tightening the cylinder head cover to the cylinder head side with the surrounding bolts, the seal between the two is sealed. Is going.

JP 2006-322481 A

  In the above arch part, the gasket is arranged in a curved shape, and a seal reaction force is generated in the direction perpendicular to the gasket at each part. In the case of a cylinder head cover made of synthetic resin, deformation around the arch part becomes large. It is easy and it is difficult to ensure sealing performance.

  In particular, in recent years, there has been a tendency to require a larger arch portion in relation to the actuator for the variable valve mechanism provided at the end of the camshaft. However, when such a large arch portion is provided, it is necessary for sealing. In order to ensure sufficient rigidity, the cylinder head cover must be made of metal, and it has been difficult to provide a large arch portion in the cylinder head cover made of synthetic resin.

The present invention has an arch portion that rises with respect to a reference seal surface at one end portion in the longitudinal direction, and a gasket is continuously attached to the arch portion from a side edge flange portion along the reference seal surface. In the cylinder head cover of an internal combustion engine made of synthetic resin that seals with the counterpart member by
In the arch portion, first and second bolt boss portions serving as fixing points with respect to the mating member are respectively provided on the arch root portion where the arch portion rises from the reference seal surface, and the first and second bolt boss portions are provided in the width direction. A third bolt boss portion serving as a fixing point for the counterpart member is provided at a position intermediate the second bolt boss portion,
The third bolt boss portion having a cylindrical shape is connected to the outside of the gasket support wall on which the gasket is attached to the lower edge,
The ceiling wall is extended outward in the longitudinal direction from the gasket support wall,
From the ceiling wall to the inner peripheral side of the arch portion so as to linearly connect the first bolt boss portion and the third bolt boss portion in a front view of the arch portion at a position outside the gasket support wall in the longitudinal direction. With reinforcing ribs projecting toward
The reinforcing rib extends linearly in a plan view of the arch portion, and is connected to an outer portion of the third bolt boss portion having a cylindrical shape.

  In the above configuration, the box is formed by the gasket support wall, the reinforcing rib positioned on the outer side in the longitudinal direction (longitudinal direction of the cylinder head cover) and the ceiling wall between the first bolt boss portion and the third bolt boss portion. A shaped structure is formed. And the reinforcement rib which protruded to the inner peripheral side of the arch part has connected the 1st bolt boss part and the 3rd bolt boss part linearly in the front view of the arch part. Therefore, the rigidity with respect to the seal reaction force of the gasket is increased between the first bolt boss portion and the third bolt boss portion, and good sealing performance can be obtained.

  In a preferred aspect, the reinforcing rib is configured such that, in a plan view of the arch portion, an end portion on the first bolt boss portion side is connected to the gasket support wall, and the third bolt boss portion side is on the outside in the longitudinal direction. It extends diagonally. Thereby, a box-like structure having a substantially triangular shape in a plan view is formed.

  In the present invention, the reinforcing rib is provided at least between the first bolt boss portion and the third bolt boss portion, but a similar reinforcing rib may be provided between the second bolt boss portion and the third bolt boss portion. Is possible.

  In a preferred aspect, the second reinforcing rib extending from the second bolt boss portion to the third bolt boss portion projects from the ceiling wall toward the inner peripheral side of the arch portion, and from the second bolt boss portion, A third reinforcing rib reaching the third bolt boss portion projects from the ceiling wall toward the outer peripheral side of the arch portion.

  That is, in this case, the rigidity against the seal reaction force is ensured between the second bolt boss portion and the third bolt boss portion by combining the second reinforcing rib and the third reinforcing rib with a relatively small amount of protrusion. The Thereby, the rigidity of the whole arch part can be secured without excessively narrowing the size of the substantial opening when the arch part is viewed from the front.

  In a preferred embodiment, the second reinforcing rib extends linearly in a plan view of the arch portion, and is connected to an outer portion of the third bolt boss portion having a cylindrical shape. Thereby, similarly to the reinforcing rib on the first bolt boss part side, a box-like structure is formed by the second reinforcing rib, the gasket support wall, and the ceiling wall.

  In one aspect, the third bolt boss portion is positioned substantially at the center between the first bolt boss portion and the second bolt boss portion in the width direction.

  According to this invention, the rigidity with respect to the sealing reaction force of the gasket in the arch part which is a problem in the synthetic resin cylinder head cover is improved, and the sealing performance of the arch part is improved.

The side view which showed roughly the relationship between a cylinder head and a front cover, and a cylinder head cover. The top view of the cylinder head cover of one Example. The bottom view of the cylinder head cover. The front view of the front-end part of the cylinder head cover. The perspective view of the gasket used for this cylinder head cover. The top view which expands and shows an arch part. The bottom view which expands and similarly shows an arch part. Explanatory drawing which showed the positional relationship of an arch part and the actuator for variable valve mechanisms.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows the positional relationship between a cylinder head cover 1 according to an embodiment and a cylinder head 2 and a front cover 3 of an internal combustion engine. The cylinder head 2 is fixed to the upper surface of a cylinder block 4. A metal front cover 3 is attached to the front end face across both the cylinder head 2 and the cylinder block 4. The front cover 3 projects upward from the upper surface of the cylinder head 2 so as to cover the disk-shaped variable valve mechanism actuator 5 at the front end of the camshaft from the front, and the front cover 3 allows a timing chain (not shown) to be formed. A traveling space, that is, a chain chamber is formed. The cylinder head cover 1 is attached so as to cover the upper surface of the cylinder head 2, but the front end portion extends to above the front cover 3 and is attached to the upper edge of the front cover 3.

  2 to 4 show the cylinder head cover 1. The cylinder head cover 1 is integrally molded using a hard synthetic resin such as polyamide, and has a generally rectangular dish shape as a whole. A plurality of bolt bosses 12 (individually indicated as 12a, 12b, etc.) are provided adjacent to the mounting groove 11, and four spark plug insertion holes 13 are arranged in a row at the center. Is arranged. That is, the cylinder head cover 1 of this embodiment is for an in-line four-cylinder internal combustion engine, and the direction along the cylinder row direction (the X direction in FIG. 2) corresponds to the “longitudinal direction”. The orthogonal direction (Y direction in FIG. 2) corresponds to the “width direction”. In this specification, “front” basically means the left side in the X direction in FIG. 2, and “rear” basically means the right side in the X direction in FIG. An oil inlet 14 to which an oil filler cap (not shown) is attached is provided at a position near the front end of the cylinder head cover 1.

  2 and 3, a portion on the right side of the drawing from the oil injection port 14 is a portion covering the upper surface of the cylinder head 2, and a portion on the left side of the oil injection port 14 (that is, the front end portion of the cylinder head cover 1). Is a portion located above the front cover 3. As shown in FIG. 4, the front end portion of the cylinder head cover 1 is an arch portion 15 cut out in a U shape or a trapezoidal shape corresponding to the upper edge shape of the front cover 3.

  That is, the side edge flange portions 21, 21 on both sides in the width direction of the cylinder head cover 1 are along a reference seal surface P (see FIG. 4) consisting of one plane corresponding to the upper surface of the cylinder head 2, and the arch portion 15 is The shape rises upward from the reference seal surface P into a U shape or a trapezoidal shape. Bolts (not shown) are respectively inserted into a total of 10 bolt boss portions 12 around and are fastened to the cylinder head 2 or the front cover 3. The three bolts 12d, 12e, and 12f shown in FIGS. The bolt boss portion 12 and the three bolt boss portions 12 indicated by reference numerals 12g, 12h, and 12i are provided on the side edge flange portions 21 and 21, respectively, and are fastened to the cylinder head 2 side. On the other hand, the bolt boss part 12 indicated by reference numeral 12a corresponding to the “first bolt boss part”, the bolt boss part 12 indicated by reference numeral 12b corresponding to the “second bolt boss part”, and the code corresponding to “third bolt boss part” A bolt boss portion 12 indicated by 12c is fastened to the front cover 3 side.

  As shown in FIG. 5, a gasket 16 made of an elastic material such as rubber is formed in the gasket mounting groove 11. 4 shows the arch portion 15 with the gasket 16 attached, but the gasket 16 is not attached in FIGS. The gasket 16 is tightly pressed between the cylinder head 2 and the front cover 3 and the cylinder head cover 1 by fastening bolts disposed on the respective bolt boss portions 12, thereby sealing the entire circumference of the cylinder head cover 1.

  As can be seen from FIGS. 4 and 5, in this embodiment, the rear end portion of the cylinder head cover 1 is also provided with a relatively gentle arch portion 17, but this rear end portion is the subject of the present invention. Since there is no description, the detailed explanation is omitted. As shown in FIG. 5, the gasket 16 is formed in a predetermined shape in advance, and an arch portion 16 a corresponding to the arch portion 15 at the front end of the cylinder head cover 1 and an arch portion 16 b corresponding to the arch portion 17 at the rear end of the cylinder head cover 1. It has.

  6 and 7 are enlarged views of the front end portion of the cylinder head cover 1. Hereinafter, the configuration of the arch portion 15 at the front end will be described in more detail with reference to FIG. 6, FIG. 7, and FIG. To do.

  As shown in FIG. 7, at the front end portion of the cylinder head cover 1 serving as the arch portion 15, a gasket support wall 23 having a gasket mounting groove 11 on the lower edge extends in the width direction of the cylinder head cover 1, and the side edge flange portion 21. , 21 is formed as a gasket mounting groove 11. The upper end of the gasket support wall 23 is connected to the ceiling wall 24 of the cylinder head cover 1, and the gasket support wall 23 protrudes from the ceiling wall 24 along a direction orthogonal to the reference seal surface P. In this embodiment, the lower edge of the gasket support wall 23 (in other words, the gasket mounting groove 11) that defines the U-shaped or trapezoidal cutout shape of the arch portion 15 is a front view of the arch portion 15 (FIG. 4). , Along the curved shape of the ceiling wall 24 at the front end of the cylinder head cover 1, that is, the amount of protrusion of the gasket support wall 23 from the ceiling wall 24 is substantially constant at each part of the arch portion 15. In other words, the arch portion 15 is set to the maximum size allowed from the shape of the ceiling wall 24 at the front end of the cylinder head cover 1. In order to avoid interference with the variable valve mechanism actuator 5 (see FIG. 8) housed inside, the gasket support wall 23 (gasket mounting groove 11) is shown in a plan view of FIG. However, this is not essential in the present invention, and it may be configured to extend in a straight line along the width direction. A grid-like rib 25 is provided on the ceiling wall 24 behind the gasket support wall 23 (backward in the longitudinal direction of the cylinder head cover 1). The ribs 25 are formed by intersecting the longitudinal ribs and the lateral ribs.

  As is clear from FIG. 4, the bolt boss portion 12 a (first bolt boss portion) and the bolt boss portion 12 b (second bolt boss portion) are respectively arranged at the arch root portion where the arch portion 15 rises. These bolt boss portions 12 a and 12 b are at a height position along the reference seal surface P. On the other hand, the bolt boss portion 12c (third bolt boss portion) is provided at an intermediate portion of the arch portion 15, that is, at a position that is intermediate between both the bolt boss portions 12a and 12b in the width direction, and is located near the highest top portion of the arch portion 15. Is fixed to the front cover 3.

  Here, the center bolt boss portion 12c has a cylindrical shape and is connected to the outer side surface of the gasket support wall 23 (the front side in the longitudinal direction of the cylinder head cover 1) as is apparent from FIG.

  A plate-like first reinforcing rib 27 is positioned in front of the gasket support wall 23 between the one bolt boss portion 12a and the central bolt boss portion 12c. A ceiling wall 24 is extended forward in the longitudinal direction of the cylinder head cover 1 so as to cover the space between the walls 23. The first reinforcing rib 27 extends from the front end edge of the ceiling wall 24 extending in the longitudinal direction of the cylinder head cover 1 to the inner peripheral side of the arch portion 15 along the direction orthogonal to the reference seal surface P, as shown in FIG. Thus, when the arch portion 15 is viewed from the front, the lower bolt boss portion 12a and the upper bolt boss portion 12c are linearly connected so as to project in a substantially triangular shape. That is, the lower edge 27 a of the first reinforcing rib 27 is linear in a front view of the arch portion 15, and projects from the gasket mounting groove 11 toward the inner peripheral side of the arch portion 15.

  Furthermore, in the plan view shown in FIG. 7, the first reinforcing rib 27 extends along a straight line slightly inclined with respect to the width direction of the cylinder head cover 1 (the arrow Y direction in FIG. 2), and the lower bolt boss portion. The end portion 27b near 12a substantially joins with the gasket support wall 23 and is connected to the bolt boss portion 12a. An end portion 27c near the upper bolt boss portion 12c is connected to an outer portion of the cylindrical bolt boss portion 12c (a portion on the front side in the longitudinal direction of the cylinder head cover 1). That is, the gasket support wall 23 and the first reinforcing rib 27 are connected to the cylindrical bolt boss portion 12c at a position 180 ° apart.

  Thus, a box-like structure is constituted by the three members of the gasket support wall 23, the first reinforcing rib 27, and the ceiling wall 24 between the two bolt boss portions 12a and 12c. This box-like structure has a substantially triangular shape in the plan view of FIG.

  On the other hand, between the bolt boss portion 12b on the opposite side and the central bolt boss portion 12c, a second reinforcing rib 28 is also positioned in front of the gasket supporting wall 23. The second reinforcing rib 28 and the gasket supporting wall A ceiling wall 24 is extended forward in the longitudinal direction of the cylinder head cover 1 so as to cover the space between the head 23 and the cylinder 23. The second reinforcing rib 28 protrudes from the front end edge of the ceiling wall 24 extended in the longitudinal direction of the cylinder head cover 1 toward the inner peripheral side of the arch portion 15 along the direction orthogonal to the reference seal surface P, and is below the bolt boss portion. 12b and the upper bolt boss part 12c are connected. However, the protruding amount (projecting amount) of the second reinforcing rib 28 is relatively small, and the lower edge 28a substantially coincides with the lower edge of the gasket support wall 23 in the front view of FIG. That is, the second reinforcing rib 28 protrudes from the curved ceiling wall 24 with a substantially constant protruding amount.

  In the plan view shown in FIG. 7, the second reinforcing rib 28 extends along a straight line that is slightly inclined with respect to the width direction of the cylinder head cover 1 (the arrow Y direction in FIG. 2), like the first reinforcing rib 27. The lower end 28b near the bolt boss portion 12b substantially joins with the gasket support wall 23 and is connected to the bolt boss portion 12b. An end portion 28c near the upper bolt boss portion 12c is connected to an outer portion of the cylindrical bolt boss portion 12c (a portion on the front side in the longitudinal direction of the cylinder head cover 1). That is, the end portion 28c of the second reinforcing rib 28 is continuous with the end portion 28c of the first reinforcing rib 27 via the central bolt boss portion 12c.

  As described above, the protruding amount of the second reinforcing rib 28 is relatively small between the bolt boss portions 12 b and 12 c, but the box shape is formed by the three members of the gasket supporting wall 23, the second reinforcing rib 28 and the ceiling wall 24. The structure is configured. This box-like structure is also substantially triangular in the plan view of FIG.

  Furthermore, between the bolt boss portions 12 b and 12 c where the second reinforcing rib 28 is located, a third reinforcing rib 29 is provided on the upper surface of the ceiling wall 24 so as to project toward the outer peripheral side of the arch portion 15. The third reinforcing rib 29 protrudes from the ceiling wall 24 along the direction orthogonal to the reference seal surface P with a substantially constant protrusion amount. In the plan view shown in FIG. 6, the center of the bolt boss portion 12b and the bolt boss It extends along a straight line passing through the center of the portion 12c. Therefore, if it sees through in planar view, the 3rd reinforcement rib 29 is provided in the position which follows the bisector of the gasket support wall 23 and the 2nd reinforcement rib 28 substantially.

  Here, in this embodiment, the bolt boss portion 12c located at the center of the arch portion 15 is located substantially at the center between the two bolt boss portions 12a and 12b. That is, as the span of the fixed point in the width direction of the cylinder head cover 1, the span between the bolt boss portions 12a and 12c and the span between the bolt boss portions 12b and 12c are substantially equal. For example, the difference between the two spans is less than 10% of the total span between the bolt boss portions 12a and 12b, and is less than 1% in the embodiment.

  In the configuration of the above embodiment, in addition to the two points on both sides of the arch portion 15 being fixed at the bolt boss portions 12a and 12b, the intermediate portion of the arch portion 15 is fixed at the bolt boss portion 12c. The seal reaction force of the gasket 16 acts almost radially on the arch portion 15, but between the bolt boss portions 12 a and 12 c, the above-described box-like structure is formed by the first reinforcing rib 27, the ceiling wall 24, and the gasket support wall 23. High rigidity as a beam can be obtained, and the seal reaction force can be reliably countered. Between the bolt bosses 12b and 12c, the second reinforcing rib 28, the ceiling wall 24, and the gasket supporting wall 23 serve as a beam by the cooperation of the box-shaped structure described above and the third reinforcing rib 29 on the outer peripheral side of the ceiling wall 24. High rigidity can be obtained, and the seal reaction force can be reliably countered. Therefore, high sealing performance is maintained over a long period of time around the entire circumference of the arch portion 15.

  Here, as described above, the span between the bolt boss portions 12a and 12c and the span between the bolt boss portions 12b and 12c in the width direction of the cylinder head cover 1 are substantially equal. Thus, in the above embodiment, between the bolt boss portions 12a and 12c occupying half of the total span, the first reinforcing rib 27 linearly connects both the bolt boss portions 12a and 12c on the inner peripheral side of the arch portion 15, Since the deformation at the intermediate portion is effectively prevented, the necessary rigidity with respect to the seal reaction force can be reliably obtained. On the other hand, between the bolt bosses 12b and 12c occupying the remaining half of the total span, the second reinforcing rib 28 protruding toward the inner peripheral side of the arch portion 15 is relatively small, and the first reinforcing rib 27 side In comparison, a substantial opening surface as the arch portion 15 is secured. Therefore, for example, as shown in FIG. 8, the relatively large variable valve mechanism actuator 5 is disposed slightly offset toward the bolt boss portion 12 b to accommodate the relatively large variable valve mechanism actuator 5. It becomes possible. In other words, in the above embodiment, the total span is divided into two, one side is securely secured by the first reinforcing rib 27, and the other side is combined with the third reinforcing rib 29 so that the inner circumference of the arch portion 15 is increased. By making the second reinforcing rib 28 on the side small, it is possible to achieve both the size of the opening surface required for the variable valve mechanism actuator 5 and the securing of rigidity.

  Further, as shown in FIG. 7, the first reinforcing rib 27 and the second reinforcing rib 28 and the gasket support wall 23 are connected to the central cylindrical bolt boss portion 12c at a position different by 180 °. Accordingly, the bolt axial force acts in a distributed manner on both sides, and both the first and second reinforcing ribs 27 and 28 and the gasket support wall 23 can be more reliably fixed as fixing points.

  As mentioned above, although one Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible. For example, in the above-described embodiment, the combination of the cylinder head 2 and the front cover 3 becomes the counterpart member, and the cylinder head cover 1 is attached on these members, but the member to which the arch portion 15 is attached is other than the front cover 3. It may be a member or a part of the cylinder head 2.

1 ... Cylinder head cover 1
DESCRIPTION OF SYMBOLS 15 ... Arch part 12a ... 1st bolt boss part 12b ... 2nd bolt boss part 12c ... 3rd bolt boss part 21 ... Side edge flange part 23 ... Gasket support wall 24 ... Ceiling wall 27 ... 1st reinforcement rib 28 ... 2nd reinforcement rib 29 ... Third reinforcing rib

Claims (5)

An end portion in the longitudinal direction has an arch portion rising from the reference seal surface, and a gasket is continuously attached from the side edge flange portion along the reference seal surface to the arch portion. In the cylinder head cover of an internal combustion engine made of synthetic resin that seals between
In the arch portion, first and second bolt boss portions serving as fixing points with respect to the mating member are respectively provided on the arch root portion where the arch portion rises from the reference seal surface, and the first and second bolt boss portions are provided in the width direction. A third bolt boss portion serving as a fixing point for the counterpart member is provided at a position intermediate the second bolt boss portion,
The third bolt boss portion having a cylindrical shape is connected to the outside of the gasket support wall on which the gasket is attached to the lower edge,
The ceiling wall is extended outward in the longitudinal direction from the gasket support wall,
From the ceiling wall to the inner peripheral side of the arch portion so as to linearly connect the first bolt boss portion and the third bolt boss portion in a front view of the arch portion at a position outside the gasket support wall in the longitudinal direction. With reinforcing ribs projecting toward
The cylinder head cover for an internal combustion engine, wherein the reinforcing rib extends linearly in a plan view of the arch portion and is connected to an outer portion of the third bolt boss portion having a cylindrical shape.   In the plan view of the arch portion, the reinforcing rib extends obliquely so that the end portion on the first bolt boss portion side is connected to the gasket support wall and the third bolt boss portion side is on the outside in the longitudinal direction. The cylinder head cover for an internal combustion engine according to claim 1, wherein A second reinforcing rib extending from the second bolt boss to the third bolt boss extends from the ceiling wall toward the inner periphery of the arch,
3. The internal combustion engine according to claim 1, wherein a third reinforcing rib extending from the second bolt boss portion to the third bolt boss portion projects from the ceiling wall toward the outer peripheral side of the arch portion. Cylinder head cover.   4. The cylinder head cover for an internal combustion engine according to claim 3, wherein the third bolt boss portion is positioned substantially at the center between the first bolt boss portion and the second bolt boss portion in the width direction. 5.   The said 2nd reinforcement rib is extended linearly in planar view of the arch part, and is connected to the outer side part of the said 3rd volt | bolt boss part which makes | forms cylindrical shape, The Claim 3 or 4 characterized by the above-mentioned. Cylinder head cover of internal combustion engine.

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