JP2021120539A - Attachment structure for oil mist separator - Google Patents

Abstract

To attach an oil mist separator to an internal combustion engine without using a separate member.SOLUTION: An oil mist separator 30 includes: a separation part 31 separating oil mist from blow-by gas G1; an inflow part 36 causing the blow-by gas G1 including oil mist to flow into the separation part 31; an outflow part 40 causing blow-by gas G2 from which oil mist has been separated to flow out from the separation part 31; and a discharge part 41 discharging oil O separated from the blow-by gas from the separation part 31. The discharge part 41 serves as an attachment part of the oil mist separator 30 to a cylinder head cover 18. An attachment hole 24 communicating recirculation passages formed outside and inside of the cylinder head cover is formed in the cylinder head cover 18. The discharge part 41 of the oil mist separator 30 in which the separation part 31 is disposed outside the cylinder head cover 18 is in snap-fit connection with the cylinder head cover 18 while inserted into the attachment hole 24.SELECTED DRAWING: Figure 4

Description

The present invention relates to an assembly structure of an oil mist separator for assembling an oil mist separator for separating oil mist contained in blow-by gas to an internal combustion engine.

As an oil mist separator for separating oil mist contained in blow-by gas of an internal combustion engine, a type provided separately from the internal combustion engine is known (see, for example, Patent Document 1). The oil mist separator is provided with a separator that separates the oil mist from the blow-by gas. The oil mist separator further includes an inflow portion, an outflow portion, and a discharge portion that protrude from the separation portion to the outside of the separation portion, respectively. Each of these inflow part, outflow part, and discharge part has a tubular shape, and is connected to the internal combustion engine via a pipe made of a flexible hose or the like.

The inflow section allows blow-by gas from the internal combustion engine to flow into the separation section. The outflow section causes the blow-by gas from which the oil mist has been separated to flow out from the separation section. This blow-by gas is returned to the intake passage of the internal combustion engine via piping. The discharge unit discharges the separated oil from the separation unit. This oil is returned to the cylinder head cover, crankcase, etc. of the internal combustion engine via piping.

JP-A-2015-4330

However, as described above, the posture of the oil mist separator is not stable only when it is attached to the internal combustion engine by the pipes connected to the inflow portion, the outflow portion and the discharge portion, respectively. Therefore, in Patent Document 1, the oil mist separator is assembled to the internal combustion engine by gripping the oil mist separator with a clamp attached to the internal combustion engine. In addition, it is also conceivable to form a flange on the oil mist separator and assemble this flange to the internal combustion engine by fastening members such as bolts and nuts. In any case, a member separate from the oil mist separator is required for assembling to the internal combustion engine.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an assembly structure of an oil mist separator capable of assembling an oil mist separator to an internal combustion engine without using a separate member. There is.

The assembly structure of the oil mist separator that solves the above problems includes a separation part that separates the oil mist from the blow-by gas and an inflow part that is generated in the internal combustion engine and allows the blow-by gas containing the oil mist to flow into the separation part. An oil mist separator including an outflow portion for discharging the blow-by gas from which the oil mist has been separated from the separation portion and an discharge portion for discharging the oil separated from the blow-by gas from the separation portion is used as a return path for the blow-by gas. In the structure for assembling the oil mist separator to be assembled to the internal combustion engine provided with, at least one of the inflow portion, the outflow portion and the discharge portion is an assembly portion of the oil mist separator to the internal combustion engine. The internal combustion engine is formed with an assembly hole for communicating the external and internal recirculation paths of the internal combustion engine, and the separation portion is arranged outside the internal combustion engine. The assembly portion of the above is snap-fitted to the internal combustion engine in a state of being inserted into the assembly hole.

According to the above configuration, when assembling the oil mist separator to the internal combustion engine, at least one of the inflow part, the outflow part and the discharge part is used as an assembling part, and the assembling hole provided in the internal combustion engine is assembled. It is said to be an attachment part. Then, the oil mist separator assembly portion whose separation portion is arranged outside the internal combustion engine is snap-fitted to the internal combustion engine in a state of being inserted into the assembly hole. With this connection, the oil mist separator is assembled to the internal combustion engine in a stable posture.

As described above, in the oil mist separator assembled to the internal combustion engine, the blow-by gas generated in the internal combustion engine and containing the oil mist passes through the inflow portion and flows into the separation portion. The blow-by gas separated from the oil mist at the separation section passes through the outflow section and is returned to the reflux path of the internal combustion engine. The oil separated from the blow-by gas at the separation section passes through the discharge section and is returned to the reflux path of the internal combustion engine. Regardless of which of the inflow part, the outflow part and the discharge part is the assembling part, the fluid related to the reflux of the blow-by gas passes through the assembling part and the assembling hole.

In this way, the inflow part, the outflow part, and the discharge part, which are the assembly parts, and the assembly hole formed in the internal combustion engine and into which the assembly part is inserted and snap-fitted, are fluids, respectively. In addition to functioning as a passage for the oil mist separator, it also functions as a part for assembling the oil mist separator to the internal combustion engine.

According to the above-mentioned oil mist separator assembly structure, the oil mist separator can be assembled to the internal combustion engine without using a separate member.

In one embodiment, a plan view of a cylinder head cover to which an oil mist separator is assembled. The partial plan view which shows the assembly hole in FIG. 1 enlarged. FIG. 4 is a sectional view taken along line 3-3 of FIG. The schematic cross-sectional view which shows the oil mist separator in one Embodiment together with the assembly hole of a cylinder head cover. The schematic diagram which shows the connection relationship between an oil mist separator and an internal combustion engine in one Embodiment. The schematic diagram which shows the modification of the connection relation between an oil mist separator and an internal combustion engine. The schematic diagram which shows the modification of the connection relation between an oil mist separator and an internal combustion engine. The schematic diagram which shows the modification of the connection relation between an oil mist separator and an internal combustion engine.

Hereinafter, an embodiment of the assembly structure of the oil mist separator will be described with reference to FIGS. 1 to 5.
As shown in FIG. 5, in a reciprocating internal combustion engine 10 such as a gasoline engine or a diesel engine mounted on a vehicle such as an automobile, an unburned air-fuel mixture is passed through a gap between a piston 11 and a cylinder 12 during its operation. Blow-by gas, which is composed of combustion gas and combustion gas, leaks from the combustion chamber 13 into the crankcase 14. Therefore, the internal combustion engine 10 is provided with a device for processing blow-by gas.

In this device, the intake negative pressure generated downstream of the throttle valve 17 of the intake passage 16 acts on the crankcase 14 through the blow-by gas passage 15. The negative pressure means a pressure lower than the atmospheric pressure as a reference. The blow-by gas leaking from the combustion chamber 13 is sucked into the crankcase 14 by the intake negative pressure, then returned to the intake passage 16 through the blow-by gas passage 15, and reburned in the combustion chamber 13. These blow-by gas passages 15 and intake passages 16 form a blow-by gas return path.

By the way, when the blow-by gas passes through the crankcase 14, the oil O of the internal combustion engine 10 becomes mist and is mixed with the blow-by gas. When the blow-by gas G1 containing the mist-like oil (oil mist) is returned to the intake passage 16, not only the oil O is consumed, but also the oil mist adheres to the intake system parts such as the intake valve (not shown). , May accumulate.

Therefore, in order to prevent the oil mist contained in the blow-by gas G1 from being taken away to the intake passage 16 by the flow of the blow-by gas G1, the oil mist separator 30 that separates the oil mist from the blow-by gas G1 is used. It is provided.

As shown in FIGS. 4 and 5, the oil mist separator 30 includes a separating portion 31 that separates the oil mist from the blow-by gas G1. The separation portion 31 includes an upstream half-split body 32 arranged on the upstream side (left side in FIG. 4) in the flow direction of the blow-by gas G1 and a downstream side (right side in FIG. 4) of the upstream half-split body 32 in the flow direction. ), And a non-breathable plate 51 as a collision wall arranged between the upstream half-split body 32 and the downstream half-split body 37.

The separation unit 31 is arranged above the cylinder head cover 18 of the internal combustion engine 10. In the plate 51, flow passages 52 through which the separated blow-by gas G2 and oil O flow are formed at locations that do not face the nozzle holes 34, which will be described later, and at the upper and lower portions in FIG.

The upstream half-split body 32 includes a bottom wall portion 33 and a tubular peripheral wall portion 35 extending from the peripheral edge portion of the bottom wall portion 33 to the downstream side in the flow direction. The bottom wall portion 33 is formed with a tubular inflow portion 36 extending upstream in the flow direction. The inflow portion 36 and the tubular gas outlet portion 19 provided on the cylinder head cover 18 are connected by a pipe 21. The pipe 21 is formed of a flexible hose or the like. The blow-by gas G1 generated in the internal combustion engine 10 and containing the oil mist flows in the inside of the cylinder head cover 18, the gas outlet portion 19, the pipe 21, and the inflow portion 36 in this order. The inflow unit 36 has a function of allowing the blow-by gas G1 to flow into the separation unit 31.

The bottom wall portion 33 is formed with a nozzle hole 34 having a flow path area smaller than that of the inflow portion 36 and functioning as an orifice. The oil mist is separated by the blow-by gas G1 passing through the nozzle hole 34 colliding with the plate 51. As described above, the separation method for separating the oil mist by collision is called the collision separation method.

The downstream half-split body 37 includes a bottom wall portion 38 arranged to face the bottom wall portion 33 and a tubular peripheral wall portion 39 extending from the peripheral edge portion of the bottom wall portion 38 to the upstream side in the flow direction. I have.
The bottom wall portion 38 is formed with a tubular outflow portion 40 extending downstream in the flow direction. The outflow portion 40 and the tubular gas introduction portion 22 provided on the downstream side of the throttle valve 17 of the intake passage 16 are connected by a pipe 23. Like the pipe 21, the pipe 23 is formed of a flexible hose or the like. The outflow section 40 has a function of causing the blow-by gas G2 from which the oil mist has been separated to flow out from the separation section 31.

A discharge portion 41 extending downward is formed in the lower portion of the peripheral wall portion 39. The discharge unit 41 has a function of discharging the oil O separated from the blow-by gas G1 from the separation unit 31. In the present embodiment, the discharge portion 41 is an assembly portion of the oil mist separator 30 to the internal combustion engine 10.

The following configuration is adopted for assembling the discharge unit 41 to the cylinder head cover 18.
As shown in FIGS. 1 and 2, the cylinder head cover 18 has an assembly hole extending in the vertical direction to communicate the external and internal reflux paths (blow-by gas passage 15, see FIG. 4) of the cylinder head cover 18. 24 is formed. The assembly hole 24 is an assembly portion to which the oil mist separator 30 is assembled in the internal combustion engine 10. As shown in FIGS. 2 and 4, a recess 26 recessed outward in the radial direction of the assembly hole 24 is formed at the boundary portion between the inner wall surface 25 of the assembly hole 24 and the upper surface 18a of the cylinder head cover 18. ing. The recess 26 is also recessed downward from the upper surface 18a.

As shown in FIGS. 3 and 4, the upper portion of the discharge portion 41 is composed of a cylindrical portion 42 having a cylindrical shape with both upper and lower ends open. The tubular portion 42 has an outer diameter smaller than the inner diameter of the assembly hole 24. By inserting the tubular portion 42 into the assembly hole 24, the inside of the separation portion 31 and the return path (blow-by gas passage 15) inside the cylinder head cover 18 are communicated with each other.

A protrusion 44 that protrudes outward in the radial direction from the outer wall surface 43 of the tubular portion 42 is formed on the upper portion of the tubular portion 42. The protrusion 44 has a shape and size capable of engaging with the recess 26 (see FIG. 2).

An annular groove 45 is formed on the outer wall surface 43 of the tubular portion 42, and below the protrusion 44, over the entire circumference thereof. The O-ring 46 is attached to the tubular portion 42 in the annular groove 45 as a sealing material.

A plurality of locations in the circumferential direction of the lower end portion, which is the end portion of the tubular portion 42 on the reflux path (blow-by gas passage 15) side, and four locations in the present embodiment, downward along the axis L1 of the tubular portion 42. An extending elastic engaging portion 47 is formed. The adjacent elastic engaging portions 47 are separated from each other in the circumferential direction of the tubular portion 42. Each elastic engaging portion 47 can be elastically deformed in the radial direction of the tubular portion 42 with the boundary portion with the tubular portion 42 as a base point.

At the lower end of each elastic engaging portion 47, a claw portion 48 projecting outward in the radial direction of the tubular portion 42 is formed. The amount of protrusion of each claw portion 48 from the elastic engaging portion 47 increases toward the upper side. Then, the tubular portion 42 and the portion of each elastic engaging portion 47 above the claw portion 48 are inserted into the assembly hole 24, and the protruding portion 44 is engaged with the recess 26. In this state, the upper end portion of the claw portion 48 for each elastic engaging portion 47 is located outside the lower opening of the assembly hole 24 in the radial direction. The discharge portion 41 is snap-fit-connected to the cylinder head cover 18 by hooking each claw portion 48 on the peripheral portion of the lower opening of the assembly hole 24. The O-ring 46 mounted on the tubular portion 42 is in contact with the inner wall surface 25 of the assembly hole 24, which is below the recess 26.

The protrusion 44 and the recess 26 constitute a rotation regulation mechanism A1 that regulates the discharge portion 41 from rotating in the circumferential direction of the assembly hole 24 with respect to the assembly hole 24.
Next, the operation of the present embodiment configured as described above will be described. In addition, the effects caused by the action will also be described.

When assembling the oil mist separator 30 to the cylinder head cover 18, as shown in FIGS. 4 and 5, the oil mist separator 30 is lowered from above the assembling hole 24 in the cylinder head cover 18. Along with this, each part of the discharge part 41 (cylindrical part 42, protrusion 44, elastic engaging part 47, claw part 48) and the O-ring 46 also descend.

The discharge portion 41 begins to be inserted into the assembly hole 24 from above. At the time of this insertion, the claw portion 48 at the lower end of each elastic engaging portion 47 comes into contact with the peripheral portion of the upper opening of the assembly hole 24. This contact acts as a resistance to the insertion of the discharge unit 41 into the assembly hole 24. When the oil mist separator 30 is lowered against this resistance and the discharge portion 41 is further inserted into the assembly hole 24, each elastic engaging portion 47 has a cylinder with the boundary portion with the tubular portion 42 as a base point. The shape portion 42 elastically deforms inward in the radial direction. Along with this, the claw portion 48 of each elastic engaging portion 47 moves inward in the radial direction, and the claw portion 48 can pass through the assembly hole 24.

When the oil mist separator 30 is further lowered, the discharge portion 41 is further inserted into the assembly hole 24 while elastically deforming each elastic engaging portion 47 inward in the radial direction. In the middle of lowering the oil mist separator 30, in addition to each elastic engaging portion 47, the tubular portion 42 enters the assembly hole 24 together with the O-ring 46.

When the lower surface of the protrusion 44 in the discharge portion 41 is lowered to the same height as the upper surface 18a of the cylinder head cover 18, if the protrusion 44 is located above the recess 26, the oil mist separator 30 is further lowered. As a result, the protrusion 44 enters the recess 26 from above.

On the other hand, if the protrusion 44 is not located above the recess 26, the lower surface of the protrusion 44 hits the peripheral portion of the upper opening of the assembly hole 24 in the upper surface 18a, and the oil mist separator is further increased. It becomes difficult to lower the 30 to insert the discharge portion 41 into the assembly hole 24. For this reason, the worker assembling the oil mist separator 30 erroneously oriented (angles) the oil mist separator 30 in the circumferential direction of the assembling hole 24 because the protrusion 44 is not located above the recess 26. You can notice that you are.

In this case, the oil mist separator 30 is rotated about the portion of the tubular portion 42 below the protrusion 44 while bringing the lower surface of the protrusion 44 into contact with the upper surface 18a. When the protrusion 44 is located above the recess 26, the lower surface of the protrusion 44 does not come into contact with the upper surface 18a, and the sliding resistance between the protrusion 44 and the cylinder head cover 18 becomes smaller. Therefore, the operator can know that the protrusion 44 has moved to the upper part of the recess 26.

The rotation about the discharge portion 41 is stopped, and the oil mist separator 30 is lowered again, so that the protrusion 44 enters the recess 26 from above. Then, immediately before the lower surface of the protrusion 44 contacts the bottom surface of the recess 26, or substantially at the same time as the contact, the upper end of the claw portion 48 for each elastic engaging portion 47 passes through the assembly hole 24. Each elastic engaging portion 47 elastically deforms outward in the radial direction of the tubular portion 42 due to its own elastic restoring force, and returns to the form before being inserted into the assembly hole 24. The claw portion 48 of each elastic engaging portion 47 is the lower surface 18b of the cylinder head cover 18 and is in a state of being caught in the peripheral portion of the opening on the lower side of the assembly hole 24.

The claw portion 48 for each elastic engaging portion 47 regulates the discharge portion 41 from coming out of the assembly hole 24 upward. Further, it is also regulated that the oil mist separator 30 is further lowered by contacting the lower surface of the protrusion 44 with the bottom surface of the recess 26.

In this way, the discharge portion 41 snaps to the cylinder head cover 18 with the tubular portion 42 and the portion of each elastic engaging portion 47 above the claw portion 48 inserted into the assembly hole 24. Fit connected. By this connection, the oil mist separator 30 is assembled to the cylinder head cover 18 in a stable posture.

Further, by engaging the protrusion 44 with the recess 26, the direction (angle) of the oil mist separator 30 in the circumferential direction of the assembly hole 24 can be determined, and the snap-fit connection can be performed in this state. Further, it is possible to prevent the oil mist separator 30 from being assembled to the cylinder head cover 18 in the wrong direction (angle).

As described above, the discharge portion 41 as the assembly portion and the assembly hole 24 formed in the cylinder head cover 18 each function as a passage for the oil O separated from the blow-by gas G1, and the oil mist separator 30 Functions as a portion to be assembled to the cylinder head cover 18. Therefore, in order to assemble the oil mist separator 30 to the internal combustion engine 10, it is not necessary to use separate members such as clamps, bolts, and nuts, unlike the conventional case.

Further, the oil mist separator 30 can be assembled to the cylinder head cover 18 simply by inserting the discharge portion 41 into the assembling hole 24, and the assembling workability can be improved as compared with the conventional technique. Can be done.

Further, as described above, since the protrusion 44 is engaged with the recess 26, the discharge portion 41 rotates in the circumferential direction with respect to the assembly hole 24. In other words, the oil mist separator 30 discharges. It is possible to regulate the rotation about the portion 41 as an axis.

By the way, when the internal combustion engine 10 in which the oil mist separator 30 is assembled to the cylinder head cover 18 is operated as described above, blow-by gas passes through the gap between the piston 11 and the cylinder 12 as shown in FIG. Leaks from.

On the other hand, the intake negative pressure generated downstream of the throttle valve 17 of the intake passage 16 is the pipe 23, the outflow part 40 of the oil mist separator 30, the separation part 31, the inflow part 36, the pipe 21, the gas lead-out part 19, and the internal combustion engine. It acts in the crankcase 14 via the return path (blow-by gas passage 15) in 10. Due to this intake negative pressure, the blow-by gas leaked from the combustion chamber 13 is sucked into the crankcase 14, and then sucked into the blow-by gas passage 15 from the inside of the crankcase 14. When the blow-by gas passes through the crankcase 14, oil mist flows into the blow-by gas. The blow-by gas G1 containing the oil mist flows through the blow-by gas passage 15, the gas outlet portion 19, and the pipe 21 in this order, and flows into the separation portion 31 from the inflow portion 36. As shown in FIGS. 4 and 5, the oil mist is separated from the blow-by gas G1 in the separation unit 31. That is, the blow-by gas G1 passes through the nozzle hole 34 to increase the flow velocity and inertially collides with the plate 51. Due to this collision, the oil mist in the blow-by gas G1 adheres to the plate 51 and is captured. The captured oil mist aggregates and becomes oil droplets. The oil O that has been made into oil droplets flows down along the plate 51 due to its own weight, and then mainly flows through the lower flow passage 52. The oil O is returned to the reflux path (blow-by gas passage 15) in the cylinder head cover 18 after passing through the lower portion of the peripheral wall portion 39, the discharge portion 41, and the assembly hole 24.

Further, the blow-by gas G2 after the oil mist is captured flows mainly through the upper flow passage 52 of the plate 51. The blow-by gas G2 passes through the outflow section 40, the pipe 23, and the gas introduction section 22 and is returned to the intake passage 16.

Further, an O-ring 46 is interposed between the outer wall surface 43 of the tubular portion 42 and the inner wall surface 25 of the assembly hole 24. The O-ring 46 seals between the outer wall surface 43 and the inner wall surface 25. Therefore, it is possible to prevent the oil O that has passed through the discharge portion 41 and the blow-by gas G1 inside the cylinder head cover 18 from leaking to the outside of the cylinder head cover 18 from between the outer wall surface 43 and the inner wall surface 25.

The above embodiment can also be implemented as a modified example in which the above is modified as follows. The above embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

As the collision separation type separation unit 31, in addition to the one described in the above embodiment, instead of the non-breathable plate 51, for example, a filter having air permeability and allowing blow-by gas to pass through. May be used as a collision wall. Examples of the material of the filter include a fiber structure such as non-woven fabric, paper, woven fabric, and knitted fabric, a resin foam body such as urethane, and a resin porous film. In the case of a filter made of a fiber structure, when blow-by gas passes through the filter, the oil mist adheres to the fiber surface and aggregates into oil droplets. The oil droplets flow down along the fiber surface due to their own weight.

Further, a non-breathable plate fixed to the breathable filter on the downstream side in the flow direction by an adhesive, a fixing structure or the like may be used as a collision wall.

-In the separation unit 31, as a separation method for separating the oil mist from the blow-by gas G1, a separation method different from the above-mentioned collision separation type, for example, a filtration separation type, a maze separation type (labyrinth type), a centrifugal separation type, etc. is adopted. May be done.

Contrary to the above embodiment, the protrusion 44 in the rotation regulation mechanism A1 may be formed on the inner wall surface 25 of the assembly hole 24, and the recess 26 may be formed on the tubular portion 42. Also in this case, by engaging the recess 26 with the protrusion 44 at the time of snap-fit connection, it is possible to restrict the discharge portion 41 from rotating in the circumferential direction of the assembly hole 24.

A plurality of protrusions 44 and a plurality of recesses 26 in the rotation regulation mechanism A1 may be provided. In this case, the protrusions 44 are formed at a plurality of positions on the tubular portion 42 that are separated from each other in the circumferential direction of the outer wall surface 43. The recesses 26 are formed at a plurality of positions separated from each other in the circumferential direction of the assembly hole 24. Then, in the snap-fit connected state, each protrusion 44 is engaged with the corresponding recess 26.

As shown in FIG. 6, the discharge unit 41 may be assembled to the crankcase 14 instead of the cylinder head cover 18. In this case, the crankcase 14 is formed with an assembly hole 24 for communicating the external and internal reflux paths (blow-by gas passage 15). Then, the discharge portion 41 is snap-fitted to the crankcase 14 in a state of being inserted into the assembly hole 24.

Even in this way, the oil mist separator 30 can be assembled to the internal combustion engine 10 without using a separate member as in the above embodiment.
The outflow portion 40 may be used as an assembly portion of the oil mist separator 30 for the internal combustion engine 10 instead of the discharge portion 41. In this case, for example, as shown in FIG. 7, an assembly hole 24 that communicates the external and internal recirculation paths (intake passage 16) downstream of the throttle valve 17 of the member having the intake passage 16. Is formed. Similar to the discharge portion 41 in the above embodiment, the tubular portion 42, the protrusion 44, the elastic engaging portion 47, the claw portion 48, and the O-ring 46 are provided in the outflow portion 40. The configuration of the discharge portion 41 is changed to a tubular configuration similar to the inflow portion 36 and the outflow portion 40 in the above embodiment. Then, the outflow portion 40 of the oil mist separator 30 in which the separation portion 31 is arranged outside the member is snap-fitted to the member in a state of being inserted into the assembly hole 24. Further, in this case, for example, a tubular oil introduction portion 27 that communicates inside and outside the crankcase 14 is formed. Then, the discharge portion 41 and the oil introduction portion 27 are connected by a pipe 53 made of a flexible hose or the like. Further, similarly to the above embodiment, the gas outlet portion 19 and the inflow portion 36 of the cylinder head cover 18 are connected by the pipe 21. Even in this way, although the object of the assembling portion is different, the oil mist separator 30 can be assembled to the internal combustion engine 10 without using a separate member as in the above embodiment.

The inflow section 36 may be used as the assembly section of the oil mist separator 30 for the internal combustion engine 10 instead of the discharge section 41. In this case, for example, as shown in FIG. 8, the cylinder block 29 is formed with an assembly hole 24 for communicating the external and internal reflux paths (blow-by gas passage 15). Similar to the discharge portion 41 in the above embodiment, the tubular portion 42, the protrusion 44, the elastic engaging portion 47, the claw portion 48, and the O-ring 46 are provided in the inflow portion 36. Then, the inflow portion 36 of the oil mist separator 30 in which the separation portion 31 is arranged outside the cylinder block 29 is snap-fitted to the cylinder block 29 in a state of being inserted into the assembly hole 24.

Further, in this case, the oil introduction portion 27 is formed in the crankcase 14 as in the modified example of FIG. 7. The discharge unit 41 is changed to a tubular structure as in the modified example of FIG. 7. The outflow portion 40 is changed to a tubular structure as in the above embodiment.

Then, the discharge unit 41 and the oil introduction unit 27 are connected by the pipe 53 as in the modified example of FIG. 7. Further, as in the above embodiment, the outflow section 40 and the gas introduction section 22 are connected by the pipe 23. Even in this way, although the object of the assembling portion is different, the oil mist separator 30 can be assembled to the internal combustion engine 10 without using a separate member as in the above embodiment.

-Whether the outflow portion 40 is used as an assembly portion (see FIG. 7) or the inflow portion 36 is used as an assembly portion (see FIG. 8), it is assembled with the outer wall surface 43 of the tubular portion 42. It is desirable that a sealing material such as an O-ring 46 is interposed between the inner wall surface 25 of the hole 24. This is to prevent the fluid flowing through the assembly portion and the fluid flowing through the reflux path (blow-by gas passage 15, intake passage 16) facing the assembly hole 24 from leaking from between the outer wall surface 43 and the inner wall surface 25. be.

-Two of the inflow part 36, the outflow part 40, and the discharge part 41 may be used as an assembly part of the oil mist separator 30 for the internal combustion engine 10.
In this case, assembling holes 24 for communicating the outside and the internal reflux path are formed at two locations of the internal combustion engine 10. Then, the two assembling portions are snap-fit connected to the internal combustion engine 10 in a state of being inserted into the corresponding assembling holes 24.

Further, all of the inflow part 36, the outflow part 40, and the discharge part 41 may be used as an assembly part of the oil mist separator 30 for the internal combustion engine 10.
In this case, assembling holes 24 for communicating the outside and the internal reflux path are formed at the three locations of the internal combustion engine 10. Then, the three assembling portions are snap-fit connected to the internal combustion engine 10 in a state of being inserted into the corresponding assembling holes 24.

By inserting a plurality of assembling portions into the corresponding assembling holes 24 regardless of whether the assembling portions are two or three, the orientation (angle) of the oil mist separator 30 with respect to the circumferential direction of the assembling holes 24. ) Can be decided. Further, after the oil mist separator 30 is assembled to the internal combustion engine 10, it is possible to regulate the rotation of the oil mist separator 30 about the assembled portion. Therefore, in this case, the protrusion 44 and the recess 26 may be omitted.

10 ... Internal combustion engine 24 ... Assembly hole 25 ... Inner wall surface 26 ... Recessed part 30 ... Oil mist separator 31 ... Separation part 36 ... Inflow part 40 ... Outflow part 41 ... Discharge part 42 ... Cylindrical part 44 ... Protrusion part 46 ... O-ring (Seal material)
47 ... Elastic engagement part 48 ... Claw part A1 ... Rotation regulation mechanism G1, G2 ... Blow-by gas L1 ... Axis line O ... Oil

Claims (5)

A separation unit that separates the oil mist from the blow-by gas, an inflow unit that causes the blow-by gas that is generated in the internal combustion engine and contains the oil mist to flow into the separation unit, and a blow-by gas that separates the oil mist from the separation unit. An oil mist separator for assembling an oil mist separator having an outflow portion for flowing out from the blow-by gas and a discharge portion for discharging the oil separated from the blow-by gas from the separation portion to the internal combustion engine provided with a blow-by gas recirculation path. It is an assembly structure
At least one of the inflow part, the outflow part, and the discharge part is an assembly part of the oil mist separator to the internal combustion engine.
The internal combustion engine is formed with an assembly hole for communicating the external and internal reflux paths of the internal combustion engine.
The assembly portion of the oil mist separator whose separation portion is arranged outside the internal combustion engine is a set of oil mist separators that are snap-fit connected to the internal combustion engine in a state of being inserted into the assembly hole. Attached structure. The assembly portion has a tubular portion with both ends open.
In the assembling portion and the internal combustion engine, with the tubular portion inserted into the assembling hole, the assembling portion rotates with respect to the assembling hole in the circumferential direction of the assembling hole. The assembly structure of the oil mist separator according to claim 1, wherein a rotation regulation mechanism for regulating is provided. The rotation regulating mechanism has a protrusion protruding in the radial direction of the tubular portion and one of the assembly holes, and a concave portion in the radial direction of the other of the tubular portion and the assembly hole. The oil mist separator assembly structure according to claim 2, further comprising a recess that engages with the protrusion. The oil mist separator assembling structure according to claim 2 or 3, wherein an annular sealing material is interposed between the tubular portion and the inner wall surface of the assembling hole. The assembly portion has a tubular portion with both ends open.
At a plurality of locations in the circumferential direction of the end portion of the tubular portion on the reflux path side, elastic engaging portions extending toward the reflux path side along the axis of the tubular portion are provided in the radial direction of the tubular portion. Formed to be elastically deformable,
Each elastic engaging portion is formed with a claw portion that projects outward in the radial direction.
With the tubular portion and the elastic engaging portion inserted into the assembly hole, the claw portion is hooked on the peripheral portion of the opening on the reflux path side of the assembly hole, whereby the assembly portion is formed. The assembly structure of the oil mist separator according to any one of claims 1 to 4, which is connected by snap fit.

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