JP2977813B1 - Cap structure - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To improve the yield by improving the casting quality of a cap for closing an opening hermetically using an O-ring.
Further, a cap structure which is advantageous for use in a breather device of an engine is provided. An annular projection (3) fitted to an opening (2) is provided on a cap surface, and a peripheral portion (4a) of a contact plate (4) fixed to the cap (1).
Is projected horizontally from the tip of the projection to form an O-ring fitting groove 7 having a U-shaped cross section around the projection. A space covered by the contact plate inside the projection is formed in the breather chamber 20 of the breather device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an O.D.
-This is related to a cap structure that closes an opening by pressing a ring tightly.More specifically, in a vehicle engine, etc., the opening of the camshaft installation space opened on the side of the cylinder head is sealed. The present invention relates to a cap structure suitable for a cap that closes at a distance.

[0002]

2. Description of the Related Art Conventionally, when an opening is closed in a closed state with a cap, an O-ring is often interposed between the cap and the opening to close the opening. For example, in an overhead camshaft type engine mounted on a vehicle or the like, an intake valve and an exhaust valve are mounted on a cylinder head, and these valves are opened and closed at a predetermined timing by a cam formed on a camshaft. The opening of the camshaft installation space provided on the side of the head is closed tightly with a cap,
By removing the cap, maintenance and inspection of each part and the like in the camshaft installation space can be performed.

Here, the cap used is generally
A ring-shaped projection is provided on the cap surface so as to fit into the opening, and an O-ring fitting groove having a U-shaped cross section provided around the projection is provided with an O-ring.
A ring is inserted and the O-ring is pressed against the inner wall surface of the opening to oppose the opening to hermetically close the opening.

In a four-stroke engine, gas in the combustion chamber blows into the crank chamber through the sliding surface of the piston, that is, blow-by gas may be generated, and the pressure in the crank chamber increases. It is common practice to equip a breather device that discharges from the chamber. In this case, the engine oil is mixed with the blow-by gas in the form of a mist (close to oil droplets). Therefore, in order to separate the oil contained in the gas, the inside of the cap attached to the side of the cylinder head is separated. A configuration in which the space is a breather chamber has also been proposed. As the prior art, for example, Japanese Patent Application Laid-Open No. 61-1388
No. 11 publication.

In this publication, the inner space of the cap is covered with an inner wall member, the inner wall member surface is used as an inner wall, the cap surface is used as an outer wall, and ribs are alternately projected from both wall surfaces so as to oppose the inner wall and the outer wall. A gas passage for meandering the flow of the blow-by gas is defined therebetween, and an oil component contained in the gas is separated while the blow-by gas is introduced from a gas inlet provided in the center portion of the inner wall member and flows through the gas passage. The separated oil (breather drain) is returned to the oil pan of the crankcase from the oil return hole provided in the lower part of the breather chamber, and only the gas part after the oil is separated is passed through the gas outlet provided in the upper part of the breather chamber. The air is sent to the air cleaner via a breather tube or the like.

[0006]

As described above, in a conventional die-casting cap that hermetically closes the opening of the camshaft installation space provided in the cylinder head of the engine, it is necessary to cast the cap at the stage of casting the cap. Generally, an O-ring insertion groove is provided around a protrusion as a material shape. However, depending on the shape of a cap, the O-ring insertion groove may not be directly castable around a protrusion. In such a case, since the O-ring insertion groove is machined in the thick portion of the die-cast material, the machining allowance increases, and the possibility that the cavity is exposed on the finished surface and becomes defective is increased. . In this case, the yield is deteriorated, and a cavity is found after processing, so that the number of processing steps up to that point is wasted.

[0007] Further, as a breather device for an engine, the one described in the above-mentioned publication in which the internal space of the cap is used for a breather chamber, the cap surface (outer wall) and the inner wall member surface (inner wall).
The cap and the inner wall member to be combined with the cap are both made of die-casting because of the configuration in which the ribs are alternately projected from the cap.

Therefore, an object of the present invention is to combine a die-casting cap and a plate made of a plate material to improve the yield by improving the casting quality, and is also advantageous for use in a breather device of a 4-stroke engine. It is intended to provide a cap structure.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, an annular projection is provided on a cap surface so as to fit into an opening closed by the cap. A disk-shaped contact plate was fixed to the cap, and the peripheral edge of the plate was projected horizontally from the tip of the protrusion to form an O-ring insertion groove having a U-shaped cross section with the protrusion outer peripheral surface as the bottom surface around the protrusion. In the cap structure, the plate is pressed
To provide an annular step between the peripheral part of the plate and the main part of the plate,
The tip of the projection is brought into contact with the step, and the main part of the plate is fixed with a fixing screw
It is characterized by being fixed to a cap .

[0010] With this configuration, when the abutment plate is fixed to the cap, simply inserting the main part of the abutment into the space inside the projection makes the tip of the abutment abut on the outer side of the step and is naturally positioned. Can be firmly fixed in place.
In addition, since a ring-shaped step is present on the surface of the plate, the rigidity of the plate is increased, and the flatness of the peripheral portion of the plate, which is one wall surface of the O-ring insertion groove, is maintained. Stabilizes the morphological accuracy of the ring fitting groove.

In a four-stroke engine, in the case of a cap attached to the opening of the camshaft installation space,
As in the second aspect of the present invention, the inner space of the projection covered by this plate can be a breather chamber. In this case, in order to improve the oil separation in the breather chamber,
As in the third aspect of the present invention, it is preferable that the cap surface is provided with an arc-shaped partition wall defining a gas passage in the space inside the projection and a fixing screw mounting seat for fixing the plate.

Here, a plurality of arc-shaped partitions having different diameters and a plurality of fixing screw mounting seats having different diameters in a divided configuration are appropriately arranged, and the plate is brought into contact with the tips of these partition walls and the fixing screw mounting seats so as to be arranged in the circumferential direction. To define a meandering gas passage.

[0013] With this configuration, the gas introduction port communicating with the start end of the gas passage and the oil return hole for discharging oil from the breather chamber can be easily formed in the plate by punching. Further, since no special processing is required for defining the gas passage for the plate, the plate can be formed by punching from a plate material and simple pressing.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a cap structure showing an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of a cap showing an embodiment of the present invention, and FIG. 3 shows an embodiment of the present invention. It is a partially expanded sectional view of this contact board shown.

In FIG. 1, a cap 1 is made of die-casting, and a ring-shaped projection 3 fitted on an opening 2 closed by the cap 1 is provided on a cap surface 1a and obtained by punching from a plate material. A disk-shaped contact plate 4 is fixed to a fixing screw mounting seat 5 provided on the cap 1 using a fixing screw 6, and a peripheral portion 4a of the contact plate is projected horizontally from the tip of the projection to form a periphery of the projection. O having a U-shaped cross section with 7a as the bottom surface
-Ring insertion groove 7 is formed, and O-ring insertion groove 7
-The ring 8 is inserted.

At the stage of finishing the cap 1, the cap outer surface 7a which comes into contact with the projection outer peripheral surface 7a and the opening end surface 2b of the cylinder head is finished, and as shown in FIG. Insert groove wall 1b,
A step t is provided so as to be slightly higher than the cap surface 1a, so that the O-ring insertion groove wall surface 1b and the peripheral edge portion 4a of the O-ring fitting groove are substantially the same in diameter. Thus, the cap surface 1
When the O-ring 8 moves in and out of the opening 2 together with the projection 3, the O-ring 8 elastically slides against the inner wall surface 2 a of the opening. The O-ring 8 makes it easy to move
Is pressed against the inner wall surface 2a of the opening (see FIG. 1) at a position deeper than the edge of the opening to stabilize the airtightness.

As shown in FIG. 3, the contact plate 4 is provided with an annular step 4c between the contact plate peripheral portion 4a and the contact plate main portion 4b by press working. Thus, when the main plate 4b is inserted inside the projection 3 to fix the main plate 4 to the cap 1, the front end of the projection abuts on the outer side of the step portion 4c, and the main plate 4 is naturally positioned, and the position is maintained as it is. Can be firmly fixed in place. In addition, since the contact plate 4 has the stepped portion 4c, the rigidity of the contact plate 4 is increased, the flatness of the contact plate peripheral portion 4a is maintained, and the morphological accuracy of the O-ring insertion groove 7 is improved. Stabilize.

FIG. 4 is a cross-sectional view of an essential part of an engine in which the present invention is applied to an engine, FIG. 5 is a front view of a cap showing an embodiment in which the present invention is applied to an engine, and FIG. It is a front view of this board showing an embodiment to which it is applied.

FIG. 4 shows a four-stroke engine to which the present invention is applied. In the engine, a cylinder 10 is connected to a crankcase 9 and this cylinder 1
The piston 11 slidably fitted in the cylinder 0 is connected via a connecting rod 12 to a crankshaft 13 which is pivotally supported by a crank chamber 9 a of the crankcase 9. In the figure, reference numeral 9b denotes an oil pan formed at the bottom of the crankcase 9.

Cylinder head 1 connected to cylinder 10
4, a camshaft installation space 15 is formed, and a camshaft 16 is pivotally supported in this space 15.
6 is connected to the crankshaft 13 via a chain sprocket transmission mechanism 17. The chain 17a constituting the chain sprocket transmission mechanism 17 is passed through a chain tunnel 18 formed in the cylinder 10 and the cylinder head 14. Further, the camshaft installation space 15 and the crank chamber 9a are communicated by the chain tunnel 18.

An opening 15a of the camshaft installation space 15 is provided on one side surface of the cylinder head 14, and a cap 19 is attached to the opening 15a so as to be hermetically closed. In this embodiment, a breather chamber 20 of a breather device is formed in the cap 19. This breather room 2
0 is a ring-shaped projection 2 provided on the cap surface of the cap 19.
1 is formed by covering the inner space with a contact plate 22.

The present embodiment, that is, the embodiment in which the present invention is applied to an engine, is also described in FIGS.
In the embodiment shown in FIG. 3, a die plate cap 1 is combined with a plate 4 made of a plate material, the plate 4 is fixed to the cap 1 using fixing screws 6, and an O-ring fitting groove 7 is formed around the projection. Is formed, and the O-ring 8 fitted in the O-ring fitting groove 7 is pressed against the inner wall surface of the opening, so that the opening is hermetically closed.

In this embodiment, as shown in FIG. 5, in addition to projecting a plurality of arc-shaped partition walls 23 having different diameters in an appropriately arranged divided configuration on the cap surface inside the projection 21,
A plurality of fixing screw mounting seats 24 and the like for fixing the fixing plate 22 are integrally provided, and the fixing plate 22 is brought into air-tight contact with these arc-shaped partition walls 23 and the upper ends of the fixing screw mounting seats 24 (see FIG. 4). A gas passage 25 meandering in the circumferential direction, communicating with the end of the gas passage 25, penetrating the upper portion of the cap, and discharging the gas separated from the oil to the outside.
6 are provided.

As shown in FIG. 6, a gas inlet 27 for introducing blow-by gas into the breather chamber 20 has a
2, an oil return hole 28 for discharging the oil separated in the breather chamber 20 to the outside is provided at a lower portion of the plate 22.

In the above configuration, when the blow-by gas from the crank chamber 9a in FIG. 4 is introduced into the breather chamber 20 from the gas inlet 27 (see FIG. 6) at the upper part of the plate via the chain tunnel 18, the gas passage 25 ( During the meandering flow in FIG. 5, the oil component is separated, adheres to the respective surfaces constituting the breather chamber 20, flows down naturally, reaches the lower part of the plate, and returns to the oil return hole 28 (FIG. 6). ) And returned to the oil pan 9a. The gas from which the oil has been separated reaches the end of the gas passage and reaches the gas outlet 2
6 (see FIG. 5) to an air cleaner (not shown) through a breather tube and the like.

[0027]

The present invention is embodied in the form described above. According to the present invention, an annular projection is provided on the cap surface.
Attach a disk-shaped plate to the girder cap, and
The O-ring around the protrusion
In a cap structure with a fitting groove,
To fix the plate, use the ring-shaped step provided on the periphery of the plate.
The tip of the ring-shaped projection abuts on the outside, and the
The plate is fixed so that the plate is fixed to the cap.
I can fix it completely. Also, there is a ring-shaped step on the plate surface.
The rigidity of the plate increases,
While maintaining the flatness of the peripheral edge of the plate, which is one of the walls, O-
Stabilizes the morphological accuracy of the ring fitting groove.

In a vehicle engine or the like, as a cap for closing an opening of a camshaft installation space of a cylinder head, a breather chamber is formed by effectively utilizing an inner space of a projection forming an O-ring insertion groove. Therefore, the breather device can be made compact.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cap structure showing an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the cap according to the embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view of this plate showing the embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of an essential part of an engine in which the present invention is applied to an engine.

FIG. 5 is a front view of a cap showing an embodiment in which the present invention is applied to an engine.

FIG. 6 is a front view of the plate showing an embodiment in which the present invention is applied to an engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 1a Cap surface 1b O-ring fitting groove wall surface 2 Opening 2a Opening inner wall surface 2b Opening end surface 3 Circular projection 4 Applicable plate 4a Applicable plate peripheral edge 4b Applicable plate main part 4c Circular annular step 5 Mounting seat 6 Fixing screw 7 O-ring insertion groove 7a Projection outer peripheral surface 8 O-ring 9 Crank case 9a Crank chamber 9b Oil pan 10 Cylinder 11 Piston 12 Connecting rod 13 Crank shaft 14 Cylinder head 15 Cam shaft installation space 15a Opening 16 Cam shaft 17 Chain sprocket transmission mechanism 17a Chain 18 Chain tunnel 19 Cap 20 Breather chamber 21 Projection 22 Applicable plate 23 Arc-shaped partition wall 24 Fixed screw mounting seat 25 Gas passage 26 Gas outlet 27 Gas inlet 28 Oil return hole

Claims (3)

(57) [Claims] An annular projection is provided on the cap surface to fit into an opening closed by the cap, a disk-shaped plate is fixed to the cap, and the peripheral edge of the plate is projected horizontally from the tip of the projection. Around the protrusion, in a cap structure having an O-ring fitting groove having a U-shaped cross section with the protrusion outer peripheral surface as a bottom surface ,
Pressing the said plate, between the periphery of the plate and the main part of the plate
Is provided with a ring-shaped step portion, and the tip of the projection is brought into contact with the step portion.
And a cap structure in which the main portion of the plate is fixed to the cap with a fixing screw . 2. The cap structure according to claim 1, wherein a space inside the projection covered by the plate is a breather chamber. 3. The cap structure according to claim 1, wherein a partition wall defining a gas passage in the space inside the projection and a fixing screw mounting seat for fixing the plate are provided on the cap surface.