JP2000170604A - Synthetic resin-made cylinder head cover for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a metallic collar from being loosened and slipping off even if the effect reaches a flange when a synthetic resin-made cylinder head cover is thermally contracted by receiving heat from an engine. SOLUTION: Metallic collars 17 slightly higher than the thickness of flanges 11c, having collar-shaped protrusions 17a on upper and lower ends, and having irregularities in the longitudinal direction of the front surfaces are insert-molded and embedded in the flanges 1c projecting outward from the lower ends of the peripheral walls 11b of a synthetic resin-made cylinder head cover 11 formed of a ceiling wall 11a and the peripheral walls 11b into such a box shape that the lower end is opened. The peripheries of the lower ends of the metallic collars 17 are surrounded with a synthetic resin, bolts are inserted into the metallic collars 17 of respective flanges 11c, and a cover 11 is clamped on a cylinder head H. Therefore, even if the cylinder head cover 11 is thermally contracted by receiving heat from an engine and that affects the flanges 11c, the metallic collars 17 are not loosened and does not slip off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a synthetic resin cylinder head cover for an engine.

[0002]

2. Description of the Related Art A cylinder head cover for an engine is mounted on a cylinder head H as shown in FIGS.
The valve mechanism M including the rocker arm a, the valve rod b, and the camshaft c disposed on the cylinder head H is prevented from being contaminated by dust and water droplets. It is made of a synthetic resin such as polyamide, polyethylene, polybutylene, and terephthalate, and a partition chamber 2 made of a synthetic resin or an iron plate is attached to the inside of the cylinder head cover 1 along the ceiling wall 1a to form a separation chamber 3. In the separation chamber 3, a plurality of downward or upward collision plates 4a, 4b are provided alternately at intervals on the ceiling wall 1a and the hollow partition plate 2, and the middle partition plate 2 has blow-by gas on one side. And an oil drain 2b on the other side. The blow-by gas generated during operation of the engine is introduced into the separation chamber 3 and the oil contained in the gas is introduced. While separating Le, gas is removed of the oil is from the outlet pipe 5 provided on the other side of the ceiling wall 1a so as to return to the intake pipe side.

As shown in FIGS. 7 and 8, a recess 1d having a predetermined width and depth is provided annularly on the lower surface of the peripheral wall 1b of the cylinder head cover 1, and acrylic rubber, acrylonitrile pig is provided in the groove 1d. A band-shaped elastic packing 6 made of a flexible rubber material such as a rubber or urethane rubber is press-fitted with its lower end protruding from the lower surface of the cover.
A plurality of flanges 1 projecting outward at the lower end of the peripheral wall 1b.
c are provided at intervals, and the screw holes 1e formed in the flanges 1c are provided with a metal collar 7 made of a hard metal such as a steel pipe, which is slightly longer than the thickness of the flange 1c portion. The cylinder head cover 1 is press-fitted so that the lower end protrudes from the lower surface of the flange. The peripheral flanges 1c of the cylinder head cover 1 are superimposed on the flange portion of the cylinder head H. Screw 6 into the packing 6
The lower end of the metal collar 7 is pressed against the upper surface of the cylinder head H while compressing and deforming the cylinder head H to form a slight gap between the cover 1 and the cylinder H, thereby preventing engine vibration from being transmitted to the cylinder head cover 1 and covering the cover. Flange 1
A creep deformation does not occur in the portion c, and the two are air-tightly connected.

[0004]

In the conventional means for mounting a cylinder head cover, the metal collars 7 are press-fitted into screw holes 1e provided in the flanges 1c at the lower end of the cover. The bolt 8 is screwed into the cylinder head H with intervention to prevent creep deformation of the flange 1c of the cover made of synthetic resin.
At the beginning of use when the cylinder head H is mounted on the cylinder head H, the synthetic resin forming the cylinder head cover 1 undergoes thermal contraction due to heat (100 ° C. to 150 ° C.) transmitted from the engine, and as a result, as shown in FIG. 1c
When the cylinder head cover 1 is removed from the engine at the time of subsequent maintenance, the through hole 1e for screw insertion provided at the inner part is deformed so that the inner half is separated from the metal collar 7 as shown by a dotted line, and the metal collar 7 is loosened. In some cases, the metal collar 7 may fall off.

Therefore, according to the present invention, even when the cylinder head cover made of synthetic resin receives heat from the engine and the influence is exerted on the flange portion, the mounting portion of the metal collar is hardly loosened. An object is to prevent the metal collar from falling off.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a cylinder head cover made of synthetic resin for an engine having a rectangular box shape with a lower end opened by a ceiling wall and a peripheral wall. Is attached with a strip-shaped elastic packing with its lower part protruding, and a flange is provided at the lower end of the peripheral wall to protrude outward.This flange is slightly higher than the thickness of the flange and has irregularities in the vertical direction on the surface The metal collar is insert-molded and buried, and the periphery of the lower end of the metal collar is annularly surrounded by a synthetic resin, and a bolt is inserted through the metal collar and fastened to the cylinder head, and A metal collar with ribs protruding outward at the upper and lower ends to form irregularities in the vertical direction on the surface is insert-molded and embedded in a flange that protrudes from the lower end of the peripheral wall. It is characterized in that there was Unishi.

[0007]

1 is a cross-sectional view of a mounting state of a cylinder head cover and a cylinder head according to the present invention viewed from a lateral direction (XX line in FIG. 2). FIG. FIG. 3 shows an enlarged cross section of one flange portion, and a rectangular box-shaped cylinder head cover 11 having an open lower end is made of a synthetic material such as polyamide, polypropylene, polybutylene, or terephthalate. A valve mechanism M made of resin and mounted on a light alloy cylinder head H of the engine as described later and including a rocker arm a, a valve rod b, a camshaft c, and the like disposed on the cylinder head H. To prevent it from being contaminated by dust, water droplets, etc., and inside the cylinder head cover 11 along the ceiling wall 11a. A separation chamber 13 is formed by erection of a partition plate 12 such as a synthetic resin plate, an aluminum plate, or an iron plate. In the separation chamber 13, a plurality of downward or upward collision plates 14 a are formed on the ceiling wall 11 a and the partition plate 12. 14b
Are alternately provided at intervals, and the partition 12 has a blow-by gas inlet 12a on one side in the longitudinal direction and an oil drain 12b (not shown in FIG. 2) on the other side. The blow-by gas generated inside the engine during operation of the engine is guided to the separation chamber 13 to separate oil contained in the gas, and the oil-free gas is provided on the other side of the cover 11. The outlet pipe 15 is returned to the intake pipe side.

On the other hand, the peripheral wall 1 of the cylinder head cover 11
A groove 11d having a predetermined width and depth is annularly formed on the lower surface of 1b, and a band-like elastic packing 16 made of a flexible rubber material such as acrylic rubber, acrylobutadiene rubber, urethane rubber, etc. is formed in the groove 11d. The lower end is press-fitted so as to protrude from the lower surface of the cover, and the peripheral wall 11b is mounted.
A plurality of flanges 11c projecting outward are provided at predetermined intervals at the lower end of the.

In the center of each flange 11c,
The height is slightly larger than the thickness of the flange 11c (0.5 to 1
The metal collar 17 made of a hard metal such as a steel pipe provided with a brim-like projection 17a protruding outward at the upper and lower ends is buried by insert molding so that the upper surface thereof matches the flange surface. The portion around which the metal collars 17 protrude from the lower surface of the flange 11c (the lower protruding portion in the illustrated example) is surrounded by a synthetic resin forming the cover 11 in an annular shape.

FIG. 4 (a) schematically shows a part of a mold for insert-molding the metal collar 17, and the cylinder head cover 11 is attached to a fixed mold Da of an injection molding machine.
A cavity Dc for forming a ceiling wall 11a, a peripheral wall 11b, a flange, and the like is provided. In a peripheral flange forming portion, a pin Dp for holding a color having the same height as the metal collar 17 and a magnet for fixing the collar are provided. m is implanted into the mold by the block body B, and is attached to the back of the mold by a screw punch g.

On the other hand, a movable mold D6 has a core De for forming a ceiling wall 11a having a collision plate 14a and a peripheral wall 11b corresponding to the cavity Dc of the fixed mold Da.
And a projection Df for forming a groove 11d for packing is provided at a peripheral portion near the groove, and a position corresponding to the pin Dp of the fixed mold Da is provided at a portion where the outer flange 11c is formed. Are provided with shallow circular recesses Dg for receiving a collar having an inner diameter larger than the outer diameter of the tip of the metal collar 17.

Then, the metal collars 17 are fitted into the respective pins Dp of the fixed mold Da, and are attracted and fixed by the magnets m at the respective base ends. In this state, the movable mold Db is fixed as shown in FIG. By injecting molten resin from a nozzle n provided on the fixed platen P into a cavity formed between the cavity Dc of the fixed mold Da and the core De of the movable mold Db. As shown in FIG. 3, the cylinder head cover 11 is formed by embedding the metal collar 17 in the center of the flange 11c and surrounding the periphery of the metal collar 17 with a synthetic resin.

In this case, assuming that the inner diameter of the circular concave portion Dg for receiving the collar of the movable mold Db is equal to the outer diameter of the tip of the metal collar 17, when the two dies Da and Db abut against each other, the tip of the collar is closed. Therefore, the inner edge of the circular recess Dg is made larger than the outer diameter of the tip of the collar because there is a possibility that the mold may be damaged due to galling of the edge of the recess Dg. 4 (a) and 4 (b) show a case in which the fixed mold Da and the movable mold Db are arranged vertically, but generally both molds are arranged laterally left and right.

In the cylinder head cover 11 formed as described above, as shown in FIGS. 1 and 3, each flange 11c at the lower end of the peripheral wall is overlapped with a flange portion at the peripheral edge of the cylinder head H, and a bolt 18 for coupling is provided with a washer 19 interposed therebetween. The packing 16 mounted on the lower surface of the peripheral wall 11b is compressed and deformed (as indicated by the dotted line to the solid line in FIG. 3) by the screwing into the cylinder head H through the metal collar 17 and the surroundings are made of synthetic resin. The lower ends of the enclosed metal collars 17 are pressed against the upper surface of the cylinder head H, and the cylinder head cover 11 is airtightly attached to the cylinder head H with a slight gap.

Thus, when the cylinder head cover 11 is used immediately after molding, the ambient temperature around the engine 10
Even if the heat of about 0 ° C. to 150 ° C. is transmitted, the synthetic resin forming the cover undergoes thermal contraction, and even if the influence reaches the flange 11c, the metal collar 17 is inserted into each flange 11c. The metal collar 17 is formed and embedded, and the upper and lower ends of the metal collar 17 are provided with flange-shaped projections 17a that protrude outward. The collar surface is formed with vertical irregularities (jagging). Compared to a metal collar with a uniform outer diameter attached to the flange by post-processing,
The attachment portion is unlikely to be loosened due to detachment of the resin, and there is no risk of falling off from the flange 11c.

If the metal collar 17 is provided with rib-like projections 17a at the upper and lower ends as shown in the figure to form irregularities in the vertical direction of its surface, the bolt 18 can be fastened when the metal surfaces contact each other. It is preferable because a wide surface can be secured and creep deformation of the synthetic resin can be more reliably prevented. However, as a means for forming irregularities on the surface of the metal collar, the projection 17a is provided at one of the upper and lower ends at an intermediate height position. May be provided, or a recess may be formed instead of the projection 17a, or both may be mixed. Further, the projection or the recess may be intermittent rather than all around. It may be provided.

In the illustrated example, the cylinder head cover 1
A partitioning plate 12 is provided inside 1 to form a separation chamber 13,
The blow-by gas generated in the engine is introduced there,
Although the one that separates from the gas is shown, it is not always necessary to do so, and in the example shown in the figure, the one in which a plurality of flanges 11c project from the lower end of the cover peripheral wall 11b is shown. The metal collar 17 may be provided all around and the metal collar 17 may be embedded at a predetermined position.

[0018]

According to the present invention, there is provided a cylinder head cover made of synthetic resin for an engine.
Since it is configured as follows, it receives heat from the engine during use immediately after molding of the cylinder head cover,
Even if the synthetic resin that forms the cover is thermally shrunk and the effect is exerted on the flange, the metal collar mounting portion will not loosen as in the past, and the metal collar will It won't fall off. In addition, there is no possibility of breakage due to galling of the fixed mold and the movable mold during molding of the cover. Further, according to the second aspect of the present invention, it is possible to secure a wide metal contact surface between the bolt head and the metal collar and between the metal collar and the cylinder head cover at the time of fastening the bolt, thereby further reducing creep deformation of the synthetic resin. It can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a use state of a cylinder head cover according to the present invention.

FIG. 2 is a bottom view of a longitudinal half of the cylinder head cover according to the present invention.

FIG. 3 is an enlarged sectional view of a flange portion.

FIG. 4A is a partial schematic side view of a state in which a molding die of a cylinder head cover is separated, and FIG. 4B is a schematic side view of a part of a butted state.

FIG. 5 shows a conventional cylinder head cover;
Sectional drawing along the -Y line.

FIG. 6 is a transverse sectional view taken along the line ZZ in FIG. 7;

FIG. 7 is a bottom view of a conventional cylinder head cover.

FIG. 8 is an enlarged sectional view of the flange portion.

FIG. 9 is a plan view showing a deformed state of a conventional metal collar mounting portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Cylinder head cover 11a Ceiling wall 11b Peripheral wall 11c Flange 12 Middle partition plate 13 Separation chamber 14a Impact plate 14b Impact plate 15 Outlet pipe 16 Packing 17 Metal collar 17a Projection 18 Bolt H Cylinder head

Claims (2)

[Claims] 1. A rectangular box-shaped box made of synthetic resin and having a ceiling wall and a peripheral wall open at the lower end, and a belt-shaped elastic packing is attached to the lower surface of the peripheral wall with the lower part protruding, and attached to the lower end of the peripheral wall. Is provided with a flange that protrudes outward, inserts a metal collar that is slightly higher than the thickness of the flange and has unevenness in the vertical direction on the surface by insert molding and embeds the periphery of the lower end of the metal collar A cylinder head cover made of a synthetic resin for an engine, wherein the cylinder head is made to be annularly surrounded by a resin, and a bolt is inserted through the metal collar and fastened to the cylinder head. 2. A metal collar having a rib-like projection projecting outward at upper and lower ends and having irregularities formed in a longitudinal direction of a surface thereof is insert-molded into a flange projecting from a lower end of a peripheral wall and embedded. The cylinder head cover made of synthetic resin for the engine according to claim 1, wherein: