JP2015105628A - Oil drain structure for oil mist separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress posture change of a check valve 10 that repeats open/close operations and prevent breakage and falling of the check valve 10 due to collision with other parts in a pre-assembly phase.SOLUTION: An oil drain structure includes: a drain pipe 5 extending downward from a bottom surface of an oil mist separator; and the check valve 10 for opening and closing an oil discharging hole 8 thereof from the outer side. The drain pipe 5 includes a cylindrical guide member 21 to encircle an outer periphery of a movement space of a valve body 11 of the check valve 10, thereby restricting inclination of the check valve 10 and protecting against collision with the other parts.

Description

  The present invention relates to an oil drain structure of an oil mist separator that processes blow-by gas of an internal combustion engine.

  As is well known, the head cover of an internal combustion engine is provided with an oil mist separator that separates and removes oil mist in blow-by gas blown from the combustion chamber into the crankcase. This oil mist separator separates oil mist from blow-by gas using a collision plate or the like, supplies the separated gas to the intake system, and returns the separated oil to the inside of the internal combustion engine through a drain pipe. Yes.

  Here, when the pressure difference between the inside of the oil mist separator and the inside of the engine where the intake negative pressure acts becomes large, the oil flows backward from the inside of the engine through the drain pipe to the inside of the oil mist separator, or to the intake system by blow-by gas. Oil may be taken out or blown out.

  As a countermeasure, Patent Document 1 discloses an oil separator in which a check valve is provided in an oil discharge hole at a lower end of a drain pipe. The check valve connects a valve body that opens and closes an oil discharge hole from the lower surface side, a valve head that is fitted in a drain pipe through a minute gap that becomes an orifice, and the valve body and the valve head. The shaft portion penetrates the oil discharge hole.

  In this case, when blow-by gas flows through the oil discharge hole due to the pressure difference between the pressure inside the engine and the negative pressure inside the oil mist separator, the valve head is attached upward by the flow through the minute gap that becomes the orifice. The force acts, and the valve body connected through the shaft portion closes the oil discharge hole from the lower surface side. On the other hand, when oil accumulates in the drain pipe and the oil level rises, the gravity of the oil acts downward on the check valve and eventually the check valve moves downward and the valve body discharges the oil. Open the hole.

  By repeating such an operation, the check valve can be maintained in a substantially closed state without excessive accumulation of oil in the drain pipe, and the flow of blow-by gas and the back flow of oil are suppressed.

International publication WO2013 / 094452A1

  However, in the configuration of Patent Document 1, the valve body positioned below the oil discharge hole is not restricted in the radial direction, and a substantial oil flow path is provided between the shaft portion and the inner periphery of the oil discharge hole. Therefore, the check valve posture tends to be unstable due to vibrations of the internal combustion engine, acceleration during traveling of the vehicle, and the like. For example, there is a concern that as a result of the check valve moving up and down in a posture inclined with respect to the oil discharge hole, the shaft portion is caught by the opening edge of the oil discharge hole, and the desired opening / closing operation cannot be obtained.

  Moreover, in the structure of patent document 1, since the non-return valve (especially valve body part) protrudes further downward from the lower end of the drain pipe which protruded elongate downward, it is in a state before assembling to the internal combustion engine. It may easily collide with parts, and the check valve may be damaged or fall out of the oil discharge hole.

The present invention relates to an oil drain structure of an oil mist separator that separates oil mist from blow-by gas of an internal combustion engine, supplies the separated gas to an intake system, and discharges the separated oil into the internal combustion engine through a drain pipe. ,
An oil discharge hole is formed at the lower end of the drain pipe along the axial direction of the drain pipe, and has a check valve for opening and closing the oil discharge hole,
This check valve
A valve body located below the oil discharge hole and opening and closing the oil discharge hole from the lower surface side;
A valve head that is fitted in the drain pipe through a micro gap serving as an orifice and is movable in the axial direction of the drain pipe;
A shaft portion extending through the oil discharge hole and connecting the valve body and the valve head;
With
Furthermore, a guide member is provided at the lower end of the drain pipe to surround the outer periphery of the moving space of the valve body.

  In a preferred embodiment, the valve head has a spherical shape so that a minute gap serving as an orifice can be stably obtained, and sits swingably on a seat at the upper end of the oil discharge hole.

  In the check valve of the present invention, for example, the negative pressure of the intake system during operation of the engine is reduced by the oil mist separator while the valve body is spaced below the lower end opening of the oil discharge hole and the oil discharge hole is open. As the valve head located in the drain pipe through a minute gap that is an orifice is sucked upward by the negative intake pressure, the check valve rises, that is, moves in the valve closing direction. The body closes the oil discharge hole. On the other hand, when oil accumulates in the drain pipe in this closed state and the oil level rises, the gravity of the oil acts downward on the check valve and eventually the check valve moves downward. The valve body opens the oil discharge hole. Thereby, the oil in the drain pipe is discharged. After the oil is discharged, the check valve is closed again by the intake negative pressure. Therefore, during the operation of the internal combustion engine, the operation is repeated such that when the check valve is closed and a sufficient amount of oil is accumulated, the check valve is opened and the oil is discharged. Inflow of blow-by gas is suppressed without accumulating excessively.

  And in this invention, the guide member surrounds the outer periphery of the movement space of the valve body which moves up and down. Therefore, the excessive inclination of the check valve is limited, and the posture of the check valve during operation becomes stable.

  Further, since the valve body is surrounded by the guide member, the check valve is protected from contact with the outside, and the check valve is prevented from being damaged or dropped before being assembled to the internal combustion engine.

  In a preferred embodiment, the guide member has a cylindrical shape having an inner diameter larger than the diameter of the valve body. Such a cylindrical guide member may be further provided with a plurality of slits extending in the vertical direction.

  In another preferred embodiment, the guide member is composed of a plurality of bar-shaped members extending in the vertical direction, and these bar-shaped members are arranged so as to surround the outer periphery of the moving space.

  According to this invention, the posture of the check valve that repeats opening and closing operations by the flow of blow-by gas in the drain pipe and the dead weight of the oil becomes stable. The characteristics of the period can be obtained more stably.

  Further, the check valve can be protected from damage or the like before being assembled to the internal combustion engine.

The schematic block diagram which shows the oil mist separator with which the oil drain structure of this invention is applied. Sectional drawing which shows the drain pipe lower end part in 1st Example. Sectional drawing along the AA line of FIG. 2 which shows a seating surface. The front view which shows the drain pipe lower end part in 2nd Example. Sectional drawing of this 2nd Example. The front view which shows the drain pipe lower end part in 3rd Example. The bottom view of the drain pipe lower end in this 3rd Example. Sectional drawing which shows the drain pipe lower end part in 4th Example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the oil mist separator 1 is provided inside a cylinder head cover that is attached so as to cover the upper surface of the cylinder head of the internal combustion engine, and includes a gas introduction unit 2 that introduces blow-by gas from the crank chamber. , An oil mist separation part 3 for separating the oil mist from the introduced blow-by gas, a gas outlet part 4 for supplying the gas after oil mist separation to the intake system, and the separated oil to the inside of the cylinder head of the internal combustion engine And a drain pipe 5 for discharging. In the oil mist separation unit 3, gas-liquid separation is performed, for example, by causing blow-by gas to collide with the collision plate. The drain pipe 5 extends substantially vertically downward from the lower wall portion of the oil mist separator 1 in a vehicle-mounted state, and its lower end opens to the inside of the cylinder head, and the oil in the oil mist separator 1 is dropped into the cylinder head. Is configured to do. A check valve 10 is attached to the lower end of the drain pipe 5. The drain pipe 5 is integrally provided with a cylindrical guide member 21 which is a main part of the present invention. An oil drain structure is configured with these drain pipe 5, check valve 10 and guide member 21 as main components.

  2 and 3 show a first embodiment of the oil drain structure. The drain pipe 5 is formed integrally with at least a part of the oil mist separator 1 from a synthetic resin material, and mainly includes a cylindrical tube portion 6 extending downward from the bottom wall portion of the oil mist separator 1. A seat portion 7 having a substantially conical surface protruding downward is provided inside the lower end portion of the drain pipe 5, and an oil discharge hole having a smaller diameter than the inner diameter of the cylinder portion 6 is provided at the center of the seat portion 7. 8 is formed penetrating along the axial direction of the drain pipe 5.

  In addition, three auxiliary oil discharge passages 9 extending in the radial direction are formed at equal intervals in the circumferential direction in the seating portion 7 positioned around the oil discharge hole 8. Each auxiliary oil discharge passage 9 is formed in a slit shape extending in the radial direction, and thus the seat portion 7 is substantially divided into three arc-shaped portions (see FIG. 3). Therefore, even when the valve head 12 of the check valve 10 described later is seated on the seat 7, the oil accumulated in the drain pipe 5 can be discharged from the oil discharge hole 8 through the auxiliary oil discharge passage 9. .

  The check valve 10 is fitted with a triangular pyramid-shaped valve body 11 disposed below the oil discharge hole 8 of the drain pipe 5 and a minute gap 14 serving as an orifice in the cylindrical portion 6 of the drain pipe 5. The valve head 12 and a shaft portion 13 having a rod-like shape that connects the two together are formed. The valve head 12 accommodated in the cylinder portion 6 can move in the axial direction of the drain pipe 5 due to the presence of the minute gap 14, and the shaft portion 13 has a smaller diameter than the oil discharge hole 8. Similarly, the oil discharge hole 8 is penetrated while being movable in the axial direction of the drain pipe 5. Accordingly, the check valve 10 can move by a predetermined amount in the axial direction of the drain pipe 5, that is, in the vertical direction as a whole. The valve body 11 located at the lower end of the check valve 10 closes the lower end opening of the oil discharge hole 8 when the check valve 10 is located at the uppermost position, and the oil discharge is performed at the position where the check valve 10 is lowered. Hole 8 is opened.

  The valve head 12 has a spherical shape with a predetermined radius. Specifically, the radius of the valve head 12 is shorter by the minute gap 14 than the radius of the inner peripheral surface of the cylindrical portion 6. Since the valve head 12 has a spherical shape in this way, the size of the minute gap 14 does not change even when the check valve 10 is tilted. As shown in FIG. 2, the valve head 12 is seated on a seating portion 7 provided at the upper peripheral edge of the oil discharge hole 8 when the check valve 10 is in the open state where the check valve 10 is located at the lowest position. Since the valve head 12 is spherical, the check valve 10 can swing even when the valve head 12 is seated. In this valve open state, the oil accumulated in the drain pipe 5 is discharged into the engine below via the minute gap 14 between the valve head 12 and the cylinder portion 6 and the auxiliary oil discharge passage 9. . The inner peripheral surface of the cylindrical portion 6 is formed in a simple cylindrical shape having a constant passage cross section at least in a range in which the valve head 12 moves.

  The valve body 11 is a triangular pyramid composed of a flat seal surface 11a that closes the lower end opening of the oil discharge hole 8 when the check valve 10 is located at the uppermost position, and a conical surface 11b at an appropriate angle on the lower surface side. Form.

  In the present embodiment, the check valve 10 is integrally formed by using a rubber material by three members of the valve body 11, the valve head portion 12, and the shaft portion 13. The check valve 10 is assembled to the oil discharge hole 8 by utilizing elastic deformation of rubber. For example, the check valve 10 is inserted into the inside of the cylindrical portion 6 from above and a pressure difference is applied using air pressure, so that the triangular pyramid-shaped valve body 11 passes through the oil discharge hole 8 while being elastically deformed. Therefore, a complicated process such as making the distal end portion of the cylindrical portion 6 into a half structure or joining the valve body 11 and the valve head portion 12 integrally after the shaft portion 13 is inserted is unnecessary.

  The check valve 10 is opened and closed depending on the relationship between the flow of blow-by gas that is about to flow into the oil mist separator 1 from the internal space of the cylinder head through the oil discharge hole 8 and the weight of the oil accumulated in the drain pipe 5. Repeat the operation. Thus, the oil accumulated in the drain pipe 5 can be reliably discharged into the cylinder head while preventing the flow of blow-by gas through the oil discharge hole 8 and the back flow of oil.

  On the other hand, a guide member 21 that protects and guides the check valve 10 is provided so as to extend further downward from the lower end of the drain pipe 5. In the first embodiment, the guide member 21 is formed of a synthetic resin material integrally with the drain pipe 5 and has a simple cylindrical shape having an outer diameter equal to the outer diameter of the drain pipe 5. Therefore, in terms of appearance, the drain pipe 5 and the guide member 21 form one continuous cylindrical shape.

  As shown in FIG. 2, when the check valve 10 is at the lower end position, the guide member 21 extends below the lower end vertex of the valve body 11. That is, the cylindrical guide member 21 is provided so as to surround the outer periphery of the movement space over the entire length of the movement space of the valve body 11 accompanying the vertical movement of the check valve 10. The inner peripheral surface 21 a of the guide member 21 has a simple cylindrical surface, and has an inner diameter slightly larger than the diameter of the valve body 11 so that an appropriate gap 22 is formed between the outer peripheral edge of the valve body 11. doing. Here, the gap 22 in the guide member 21 is set to be larger than the minute gap 14 between the valve head 12 and the inner peripheral surface of the cylindrical portion 6, and the characteristic change due to the flow of blow-by gas passing through the gap 22 can be as much as possible. It does not occur. On the contrary, if the gap 22 is excessively large, the change in the posture of the check valve 10 is allowed, so that the shaft portion 13 contacts the opening edge of the oil discharge hole 8 even if the check valve 10 is tilted to the maximum. It is desirable to set the size of the gap 22 to such an extent that it does not occur.

  According to the oil drain structure provided with the guide member 21 as described above, when the check valve 10 is about to tilt due to vibration of the internal combustion engine, acceleration during traveling of the vehicle, or the like, the valve body 11 can be Since it contacts the surface 21a, the inclination of the check valve 10 is limited. Therefore, the posture of the check valve 10 that repeats the opening and closing operation becomes stable, and for example, the shaft portion 13 is not caught by the opening edge of the oil discharge hole 8 and temporarily does not malfunction.

  Further, since the check valve 10 is surrounded by the guide member 21 having rigidity made of synthetic resin, the check valve 10 is protected without being exposed to the outside. For example, when the cylinder head cover provided with the oil mist separator 1 is transported as a part or attached to the cylinder head, the check valve 10 may collide with other parts and be damaged, or may fall off from the oil discharge hole 8. There is no end.

  Next, FIGS. 4 and 5 show a second embodiment of the oil drain structure of the present invention. The guide member 21 of this embodiment has a cylindrical basic shape similar to that of the guide member 21 of the first embodiment, but further includes a plurality of slits 23 extending along the vertical direction. The slit 23 forms a straight line extending in parallel with the cylindrical portion 6 and the central axis of the guide member 21, and reaches the lower end of the guide member 21.

  According to such a configuration, a guide function and a protection function for the check valve 10 can be obtained by the guide member 21 as in the first embodiment, and in particular, a space generated between the valve body 11 and the oil discharge hole 8. Is open to the outside through the slit 23, so blow-by gas and oil can flow through the slit 23. Therefore, for example, the occurrence of a pressure difference between the upper and lower portions of the valve body 11 in the guide member 21 due to the flow of blow-by gas is suppressed, and the intended operating characteristics of the check valve 10 are not impaired.

  Next, FIGS. 6 and 7 show a third embodiment of the oil drain structure of the present invention. The guide member 21 of this embodiment is composed of a plurality of (for example, six) rod-like members 25 extending along the vertical direction. These rod-shaped members 25 are made of, for example, a synthetic resin that is integrally formed with the drain pipe 5, each of which has an elongated rod shape with a circular cross section, and extends from the lower end of the drain pipe 5 to the central axis of the drain pipe 5. It extends in parallel, and its lower end reaches below the lower end vertex of the valve body 11 when the check valve 10 is in the lower end position. As shown in FIG. 7, the plurality of rod-like members 25 are arranged along a circle surrounding the outside of the valve body 11, and surround the outer periphery of the movement space of the valve body 11 as a whole.

  In the third embodiment, the check valve 10 is guided and protected by the guide member 21 as in the first and second embodiments. In particular, in this embodiment, as in the second embodiment, the inside of the guide member 21 does not become a closed space, so that the operating characteristics of the check valve 10 are not affected.

  The number of the rod-like members 25 is not limited to the illustrated embodiment, and the number of the rod-like members 25 is arbitrary as long as the position of the valve body 11 and the protection from the collision with the outside can be achieved. Further, it may be a rod-shaped member 25 having a non-circular cross section.

  Next, FIG. 8 shows a fourth embodiment of the oil drain structure of the present invention. This embodiment is a configuration suitable for a larger oil drain structure compared to the first to third embodiments, and the valve head 12 of the check valve 10 functions as a float in oil. It is formed in a hollow shape with a synthetic resin material. Therefore, when oil accumulates in the drain pipe 5, a force that urges the check valve 10 upward by buoyancy is generated, and the valve acts more reliably until the oil reaches a predetermined level.

  In this embodiment, the valve body 11 and the shaft portion 13 are also made of synthetic resin, and the valve body 11 has a simple disk shape. The seat portion 7 is divided into four arc-shaped portions.

  The guide member 21 surrounding the outer periphery of the moving space of the valve body 11 has the same configuration as that of the second embodiment, and has a cylindrical basic shape and includes a plurality of slits 23 extending in the vertical direction. Yes. The guide member 21 is also formed integrally with the drain pipe 5.

DESCRIPTION OF SYMBOLS 5 ... Drain pipe 6 ... Cylindrical part 7 ... Seating part 8 ... Oil discharge hole 10 ... Check valve 11 ... Valve body 12 ... Valve head 13 ... Shaft part 21 ... Guide member 23 ... Slit

Claims (5)

In the oil drain structure of the oil mist separator that separates the oil mist from the blow-by gas of the internal combustion engine, supplies the separated gas to the intake system, and discharges the separated oil into the internal combustion engine through the drain pipe,
An oil discharge hole is formed at the lower end of the drain pipe along the axial direction of the drain pipe, and has a check valve for opening and closing the oil discharge hole,
This check valve
A valve body located below the oil discharge hole and opening and closing the oil discharge hole from the lower surface side;
A valve head that is fitted in the drain pipe through a micro gap serving as an orifice and is movable in the axial direction of the drain pipe;
A shaft portion extending through the oil discharge hole and connecting the valve body and the valve head;
With
An oil drain structure for an oil mist separator, wherein a guide member is provided at the lower end of the drain pipe to surround the outer periphery of the moving space of the valve body.   2. The oil drain structure for an oil mist separator according to claim 1, wherein the valve head has a spherical shape and is swingably seated on a seat at the upper end of the oil discharge hole.   The oil drain structure for an oil mist separator according to claim 1 or 2, wherein the guide member has a cylindrical shape having an inner diameter larger than a diameter of the valve body.   The oil drain structure for an oil mist separator according to claim 3, wherein the guide member includes a plurality of slits extending in the vertical direction.   The said guide member consists of a some rod-shaped member extended along the up-down direction, These rod-shaped members are arrange | positioned so that the outer periphery of the said movement space may be enclosed, The Claim 1 or 2 characterized by the above-mentioned. Oil drain structure of oil mist separator.

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