JP2013124598A - Head cover of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new head cover easily manufacturable and excelling in rigidity.SOLUTION: A baffle plate 22 constituting undersurfaces of oil mist separator chambers 11, 12 is formed integrally with a plastic cover body 21 jointed to an upper surface peripheral part of a cylinder head 1 at a lower surface peripheral part. A separator upper part structure 23 of a separate body is jointed to the upper surface of the cover body 21, and the oil mist separator chambers 11, 12 are composed of the separator upper part structure 23 and the baffle plate 22.

Description

  The present invention relates to an improvement of a head cover of an internal combustion engine attached to an upper portion of a cylinder head.

  An oil mist separator chamber for separating and removing oil mist in blow-by gas blown into the crankcase from the gap between the cylinder and the piston is formed in the head cover attached to the upper part of the cylinder head of the internal combustion engine for automobiles. Yes.

  Such a head cover is generally provided with an oil mist separator chamber on the lower surface side of the cover body joined to the upper surface of the cylinder head at the lower peripheral edge as described in Patent Document 1 and Patent Document 2. The baffle plate which comprises the lower surface of this is joined, The oil mist separator chamber is comprised by this baffle plate and the cover main body.

JP 2003-293853 A JP 2011-122478 A

  However, the head cover having a structure in which a separate baffle plate is joined to the lower surface opening of the cover body as described above has the following problems. First, since the baffle plate is joined to the lower surface side of the cover body that is joined to the cylinder head on the lower surface side, the baffle plate is disposed on the inner side of the peripheral edge of the cover body. Therefore, for example, when a blow-by gas introduction port is provided in the peripheral portion of the head cover, it is necessary to provide the blow-by gas introduction port only in the cover body made of synthetic resin, and the cover body is complicated to cause an undercut that cannot be released. Therefore, it is necessary to use a jig such as a slide at the time of molding, so that the manufacturing process becomes complicated and the productivity is lowered.

  Secondly, in the case of a structure in which a plug hole into which a spark plug is inserted is formed only in the cover body between two rows of oil mist separator chambers arranged side by side in the engine width direction, there is a waste in the middle of the plug hole. The resulting shape increases product weight. Third, in a head cover in which two rows of oil mist separator chambers are arranged side by side in the engine width direction, deformation tends to occur such that both side portions in the engine width direction warp inward during molding. However, in the case of a structure in which a separate baffle plate is joined to the lower surface side of the cover body, the ribs for reinforcement cannot be provided in the lower part of the baffle plate on the cover body. Is difficult.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a novel internal combustion engine head cover that can suppress or eliminate at least one of the above-described problems.

  Accordingly, the present invention provides an internal combustion engine head cover which is attached to an upper portion of a cylinder head of an internal combustion engine and is provided with an oil mist separator chamber for separating oil mist in gas. A baffle plate constituting the lower surface of the oil mist separator chamber is integrally formed on a cover body made of synthetic resin to be joined to the portion, and the oil mist separator chamber is formed on the upper surface of the cover body together with the baffle plate. The separator upper structure which comprises is joined, It is characterized by the above-mentioned.

  Preferably, two rows of the oil mist separator chambers are juxtaposed in the engine width direction, and a plug hole into which a spark plug is inserted is provided between the two rows of oil mist separator chambers. A recessed portion that is formed through both of the upper structure and is partially recessed radially outward in the center of the plug hole in the plug axial direction across the mating surface of the cover body and the separator upper structure. Is formed.

  Preferably, ribs are provided under the baffle plate so as to span the side walls on both sides in the engine width direction of the cover body.

  More preferably, two rows of the oil mist separator chambers are juxtaposed in the engine width direction, and at the center of the cover between the two rows of oil mist separator chambers, the cover main body and the separator upper component are The mating surface portion to be joined has a closed cross-sectional structure having a hollow portion.

  Further, when there is a possibility that rainwater or the like may enter the hollow portion from the opening hole formed in the separator upper structure, preferably a drain groove for discharging the intruded rainwater or the like to the outside is provided in the cover body. Is formed.

  According to the present invention, a baffle plate is integrally formed on the cover body joined to the cylinder head on the lower surface side, and a separate separator upper structure is joined to the upper surface side of the cover body. The degree of freedom of the shape and layout of the cover main body and the separator upper structure is increased, and at least one of the above-described problems can be suppressed or eliminated.

Sectional drawing which follows the AA line of FIG. 3 which shows the head cover of the internal combustion engine which concerns on one Example of this invention. Sectional drawing which follows the BB line of FIG. 3 which shows the vicinity of the blowby gas inlet of the head cover of a present Example. The top view which shows the said head cover. The top view which shows the separator upper part structure of the said head cover alone. The top view which shows the cover main body of the said head cover independently. The bottom view which shows the said head cover. Sectional drawing which shows the head cover of the internal combustion engine which concerns on a comparative example. Sectional drawing which shows the vicinity of the blowby gas inlet of the head cover of a comparative example. Sectional drawing which shows the other joining example of the head cover which concerns on this invention.

  Hereinafter, an embodiment in which a head cover according to the present invention is applied to an in-line three-cylinder internal combustion engine will be described in detail with reference to the drawings. 1 to 6, the head cover 10 is attached to the upper portion of the cylinder head 1 and has two rows of first and second oil mist separator chambers 11 for separating oil mist in blow-by gas. , 12 are juxtaposed in the engine width direction. As shown in FIG. 3, an ignition plug (not shown) and an ignition coil (not shown) for generating a voltage necessary for discharging the spark plug are provided at the center of the head between the oil mist separator chambers 11 and 12. A plurality of (three in this example) plug holes 13 are inserted in the plug axial direction (vertical direction in FIG. 1), and an ignition coil fixing mounting hole 18 is provided in the vicinity of each plug hole 13. An opening hole 19 is formed through which a bolt for fixing the head cover 10 to the cylinder head 1 is inserted.

  As indicated by the arrows in FIG. 3, fresh air introduced from the upstream side of the throttle valve in the intake passage into the first oil mist separator chamber 11 through the fresh air inlet 14 is supplied to the fresh air outlet 15 (FIGS. 5 and 6). To the cylinder head 1 and the cylinder block side. The blow-by gas blown into the crankcase from the combustion chamber by ventilation inside the engine due to the fresh air is introduced into the second oil mist separator chamber 12 through the blow-by gas inlet 16 and is introduced into the second oil mist separator chamber 12. The oil mist is separated by an oil mist separation part such as a provided shielding plate, and the separated gas is supplied to the downstream side of the throttle valve in the intake passage via the gas outlet 17 and a PCV valve (not shown). The oil thus returned is returned to the inside of the cylinder head via a drain pipe (not shown). Further, when the load is high, the gas in the cylinder head 1 is introduced into the first oil mist separator chamber 11 from the fresh air outlet 15, and an oil mist separator such as a shielding plate provided in the first oil mist separator chamber 11. The oil mist is separated by (not shown), the separated gas is supplied to the intake passage through the fresh air inlet 14, and the separated oil is returned to the inside of the cylinder head.

  In the head cover 10 of the present embodiment, the baffle plate 22 constituting the lower surface of the oil mist separator chambers 11 and 12 is attached to the synthetic resin cover body 21 joined to the upper surface peripheral portion of the cylinder head 1 at the lower surface peripheral portion. A synthetic resin separator upper structure 23 that constitutes the oil mist separator chambers 11 and 12 together with the baffle plate 22 is joined to the upper surface side of the cover main body 21 by vibration welding.

  The cover body 21 has a shallow plate shape in which four side walls 24 project downward from the baffle plate 22, and a lower portion of the plug hole 13 is formed through the center in the engine width direction. The separator upper structure 23 is joined to the peripheral portion on the upper surface side of the cover main body 21 by vibration welding, and the upper portions of the oil mist separator chambers 11 and 12 are provided on both sides in the engine width direction, and the center in the engine width direction. An upper portion of the plug hole 13 is formed through the portion.

  7 and 8 show a head cover 10H according to a comparative example. It should be noted that “H” is appended to the constituent elements of the comparative example after the corresponding constituent elements of the present embodiment. In the head cover 10H of this comparative example, a separate baffle constituting the lower surface of the oil mist separator chambers 11H and 12H is formed in the lower surface opening of the synthetic resin cover body 21H joined to the upper surface of the cylinder head 1 at the lower surface peripheral edge. A plate 22H is joined, and the baffle plate 22H and the cover body 21H constitute oil mist separator chambers 11H and 12H. With reference to this comparative example, the characteristic configuration and operational effects of the present embodiment are listed below.

  [1] As shown in FIG. 8, the blow-by gas inlet 16H communicates the blow-by gas passage 2 provided in the side wall of the cylinder head 1 with the second oil mist separator chamber 12H. A longitudinal passage 25H communicating with the passage 2 and a lateral passage 26H having one end facing the inside of the oil mist separator chamber 12H form a substantially L-shaped passage shape. In the structure of the comparative example of FIG. 8, since the separate baffle plate 22H is joined to the lower surface side of the cover main body 21H joined to the cylinder head 1 at the peripheral edge of the lower surface, the baffle plate 22H is connected to the blow-by gas inlet. The blow-by gas introduction port 16H having a substantially L-shaped passage shape needs to be formed only by the cover main body 21H because it is positioned inside the 16H vertical passage 25H. For this reason, the cover main body 21H has a complicated shape that causes an undercut that cannot be released in the mold drawing direction (vertical direction in FIG. 8), and a jig 27 such as a slide for forming the lateral passage 26H is used during molding. This necessitates complicated manufacturing processes and reduced productivity.

  On the other hand, in the present embodiment, as shown in FIG. 2, the structure is such that a separate separator upper component 23 is joined to the upper surface side of the cover body 21 joined to the cylinder head 1 on the lower surface side. The degree of freedom of the shape and layout of the separator upper structure 23 to be joined to the upper surface side of the cover main body 21 is increased, and the joining position of both is set outside the vertical passage 25 of the blow-by gas inlet 16 of the head cover 10. It can be set at the periphery. Therefore, the blow-by gas inlet 16 can be constituted by two parts of the cover main body 21 and the separator upper structure 23. As shown in FIG. 2, the vertical passage 25 is formed in the cover main body 21, while the horizontal passage 26 is formed. By forming the cover body 21 and the separator upper structure 23 in a divided manner, both the cover body 21 and the separator upper structure 23 can have a simple shape without causing an undercut. As a result, it is possible to mold the cover main body 21 and the separator upper structure 23 without using a jig 27 such as a slide (see FIG. 8), which facilitates manufacture and improves productivity.

  [2] As shown in FIG. 7, in the comparative example, the plug hole 13H into which the spark plug is inserted between the two rows of oil mist separator chambers 11H and 12H arranged in parallel in the engine width direction is formed only in the cover body 21H. It penetrates. Here, the plug hole 13H is joined to the upper end portion where the seal portion 28H is formed and the upper surface of the cylinder head 1 so that the plug hole 13H fits at least at the upper end portion and the lower end portion with substantially no gap. The lower end portion is set to a prescribed inner diameter dimension. A seal groove 29H into which the seal member is fitted is formed at the lower end of the plug hole 13. Therefore, the plug hole 13H has the same inner diameter over almost the entire length in the plug axial direction so as not to cause an undercut, resulting in a thick shape in which sagging occurs midway, increasing the product weight.

  On the other hand, in this embodiment, as shown in FIG. 1, the plug hole 13 is formed through the two parts of the cover main body 21 and the separator upper structure 23 in the axial direction, that is, the plug hole is divided into two parts. 13 is formed. A recess 31 that is partially recessed radially outward is formed at the center in the plug axial direction of the plug hole 13 that crosses the mating surface 30 between the cover body 21 and the separator upper structure 23. Accordingly, it is possible to reduce the weight of the recess 31 by omitting the sagging of the recess 31 while ensuring the prescribed radial dimension at the upper end and the lower end of the plug hole 13. Further, by providing the mating surface 30 in the portion of the recess 31, both the cover main body 21 and the separator upper structure 23 are formed in a shape that does not cause an undercut despite the recess 31 being provided. It is easy to mold and has excellent productivity.

  [3] As shown in FIG. 1, in the head cover 10 in which two rows of oil mist separator chambers 11 and 12 are arranged in parallel in the engine width direction with the plug hole 13 interposed therebetween, as shown by an arrow Y1, It is easy to cause deformation such that both side portions in the engine width direction warp inward during mold forming. However, as shown in FIG. 7, in the case of the structure of the comparative example in which a separate baffle plate 22H is joined to the lower surface side of the cover main body 21H, reinforcing ribs are integrated into the lower portion of the baffle plate 22H on the cover main body 21H side. Therefore, it is difficult to prevent the deformation at the time of molding described above.

  On the other hand, in this embodiment, as shown in FIGS. 1 and 6, a plurality of ribs 32 are provided below the baffle plate 22 so as to span the side walls 24 on both sides in the engine width direction of the cover body 21. . The ribs 32 are integrally formed when the cover body 21 is molded. The ribs 32 are integrally connected to the lower surface side of the cover body 21 including the baffle plate 22 and cross the plug hole 13 in the engine width direction. The both side edges thereof are integrally connected to the inner surfaces of both side walls 24 of the cover body 21 in the engine width direction. By providing such ribs 32, the rigidity of the cover body 21 can be improved, and in particular, the occurrence of inward warping during cover molding can be effectively suppressed and avoided. Moreover, as shown in FIGS. 1 and 6, the rigidity around the plug hole 13 can be improved by integrally connecting the rib 32 to the portion around the plug hole 13.

  [4] By providing the above-described recess 31 in the plug hole 13, the rigidity of the plug hole 13 may be reduced. Therefore, in the present embodiment, as shown in FIG. 1, in the center portion of the cover between the two rows of oil mist separator chambers 11 and 12, the mating surface portion where the cover main body 21 and the separator upper structure 23 are joined, As a closed cross-sectional structure having the hollow portion 33, the rigidity is improved. Specifically, a plurality of belt-shaped auxiliary ribs 34 (see FIG. 5) are erected on the upper surface side of the cover body 21 and the lower surface side of the separator upper structure 23 so as to form the hollow portion 33. .

  [5] As described above, the separator upper structure 23 is formed with an opening hole 19 through which a bolt for fixing the head cover 10 to the cylinder head 1 is inserted. There is a risk of rainwater entering the door. Therefore, in this embodiment, as shown in FIG. 5, a drain groove 36 for discharging rainwater and the like that has entered the hollow portion 33 in which the opening hole 19 is formed is formed on the cover body 21 side. One end of the drainage groove 36 communicates with the hollow portion 33 where the opening hole 19 (see FIGS. 3 and 4) is formed, and the other end is exposed to the outside of the separator upper structure 23. The cover body 21 is formed so as to extend along the upper surface side, and rain water or the like accumulated in the hollow portion 33 is discharged to the outside through the drain groove 36.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes. For example, the method of joining the separator upper structure 23 and the cover main body 21 is not limited to vibration welding as in the above embodiment, but may be joining using a tapping screw 40 as shown in FIG. Alternatively, it may be joined by bolts / nuts or snap fit.

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 2 ... Blow-by gas passage 10 ... Head cover 11, 12 ... Oil mist separator chamber 13 ... Plug hole 16 ... Blow-by gas introduction port 21 ... Cover main body 22 ... Baffle plate 23 ... Separator upper structure 30 ... Matching surface 31 ... Recess 35 ... Open hole 36 ... Drain groove

Claims (5)

In the head cover of the internal combustion engine, which is attached to the upper part of the cylinder head of the internal combustion engine and provided with an oil mist separator chamber for separating oil mist in the gas,
A baffle plate that forms the lower surface of the oil mist separator chamber is integrally formed on the synthetic resin cover body that is joined to the upper surface of the cylinder head at the lower peripheral edge, and
A head cover for an internal combustion engine, wherein a separator upper structure constituting the oil mist separator chamber together with the baffle plate is joined to an upper surface of the cover body. Two rows of the oil mist separator chambers are juxtaposed in the engine width direction, and a plug hole into which a spark plug is inserted is provided between the two rows of oil mist separator chambers. Are formed through both sides,
The concave portion partially recessed radially outward is formed in a central portion in the plug axial direction of the plug hole that crosses a mating surface between the cover main body and the separator upper structure. 2. A head cover of the internal combustion engine according to 1.   The head cover for an internal combustion engine according to claim 1 or 2, wherein ribs are provided under the baffle plate so as to extend over side walls on both sides of the cover body in the engine width direction. Two rows of the oil mist separator chambers are juxtaposed in the engine width direction,
In the central portion of the cover between these two rows of oil mist separator chambers, the mating surface portion where the cover body and the separator upper structure are joined has a closed cross-sectional structure having a hollow portion. The head cover of the internal combustion engine according to any one of claims 1 to 3.   5. A drainage groove for discharging rainwater or the like that has entered the hollow portion from an opening hole formed in the separator upper structure to the outside is formed in the cover body. The head cover of the internal combustion engine according to any one of the above.

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