JP2017082631A - Oil separator for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator for an engine which can improve oil mist separating performance from blow-by gas containing the oil mist, compared to conventional technique.SOLUTION: An oil separator for an engine includes a blow-by gas inlet 51, a separation chamber, a blow-by gas outlet 52, and an oil outlet 53. The separation chamber separates oil mist from blow-by gas containing the oil mist flowing in through the blow-by gas inlet 51. The separation chamber includes a protrusion 555 with which the blow-by gas containing the oil mist collides, a labyrinth structured passage 60 having a plurality of bent portions through which the blow-by gas after colliding with the protrusion 555 passes, and a third space 562 into which the blow-by gas after passing through the labyrinth structured passage 60 flows. The blow-by gas in the third space 562 flows out of the blow-by gas outlet 52.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an engine oil separator that separates oil mist from blow-by gas containing oil mist.

  Patent Document 1 describes an example of a lubrication structure of an engine (4-cycle engine) mounted on a portable work machine. In this engine lubrication structure, the oil in the oil tank is sucked into the crank chamber and is misted in the crank chamber, and the misted oil (that is, the oil mist generated in the crank chamber) is the oil tank. Is supplied to the valve operating mechanism. The blow-by gas containing the oil mist is sent from the valve operating chamber to the air cleaner, and the oil mist is separated by an oil separator provided in the air cleaner. The separated oil mist is liquefied and sent to the crank chamber, and the blow-by gas after the oil mist separation is burned in the combustion chamber and then discharged to the outside.

JP 2012-57554 A

  In the prior art, a part of the oil mist generated in the crank chamber is liquefied when passing through the oil tank, and the mist concentration is lowered. For this reason, normally, supply of excessively concentrated oil mist to the valve mechanism is suppressed.

  However, the above prior art does not actively control the concentration of oil mist supplied to the valve mechanism. Therefore, depending on the usage state of the portable work machine, etc., excessively concentrated oil mist may be temporarily supplied to the valve mechanism, and as a result, the oil mist may not be sufficiently separated by the oil separator. There is.

  Therefore, even if the excessively concentrated oil mist is supplied to the valve operating mechanism, the performance of the oil separator is improved so that the oil mist can be sufficiently separated from the blow-by gas containing the oil mist. It is hoped that. This is common to all engine oil separators that separate oil mist from blow-by gas containing oil mist.

  Then, an object of this invention is to provide the oil separator for engines which improved the isolation | separation performance of the oil mist from the blowby gas containing an oil mist compared with the past.

  According to one aspect of the present invention, an oil separator for an engine is provided. The oil separator for an engine includes a blow-by gas inlet portion into which blow-by gas containing oil mist flows, a separation chamber for separating the oil mist from the blow-by gas containing oil mist flowing in through the blow-by gas inlet portion, and an oil A blow-by gas outlet part from which blow-by gas after mist separation flows out and an oil outlet part from which liquid oil flows out are included. The separation chamber has a collision portion where blow-by gas including the oil mist that has flowed in through the blow-by gas inlet portion collides, and a plurality of bent portions through which blow-by gas after colliding with the collision portion passes. A passage portion having a labyrinth structure and a space portion into which blow-by gas after passing through the passage portion of the labyrinth structure flows. And the blowby gas in the said space part flows out from the said blowby gas exit part.

  In the engine oil separator, the blow-by gas including the oil mist that has flowed into the separation chamber collides with the collision portion, and then flows through the passage portion of the labyrinth structure into the space portion. And the blowby gas in the said space part flows out from the said blowby gas exit part. For this reason, the oil separator for engines can flow out the oil mist after sufficiently separating the oil mist from blowby gas even when the blowby gas contains a lot of oil mist. Separation performance is improved.

1 is a schematic cross-sectional view of an engine to which an oil separator according to an embodiment of the present invention is applied. It is a figure which shows the component of the valve operating mechanism of the said engine. It is the schematic which shows the lubrication structure for lubricating the crankshaft of the said engine and the said valve mechanism, and the blowby gas processing apparatus which introduces into the intake system the blowby gas which leaked from the combustion chamber of the said engine. FIG. 4A is a plan view of the oil separator, FIG. 4B is a front view of the oil separator, and FIG. 4C is a side view of the oil separator. is there. It is a disassembled perspective view of the said oil separator. Similarly, it is an exploded perspective view of the oil separator. FIG. 5 is an AA cross-sectional enlarged view of FIG. It is a BB cross-sectional enlarged view of Drawing 4 (A). It is CC cross-section enlarged equivalent view of FIG. 4 (A). FIG. 5 is a DD cross-sectional enlarged view of FIG. It is EE sectional drawing of FIG. It is a disassembled perspective view of the oil separator by other embodiment. It is a disassembled perspective view of the oil separator by the said other embodiment similarly. It is a plane sectional view of an oil separator by the other embodiment. It is an enlarged view of FIG. 14, and is a figure which shows the flow of blow-by gas in the oil separator inside by the said other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of an engine in which an engine oil separator according to an embodiment of the present invention is used. This engine is a four-stroke engine, and is mainly used as a drive source (prime mover) of a portable work machine such as a brush cutter.

  As shown in FIG. 1, the engine 1 forms a crank chamber 5 together with a cylinder block 4 in which a cylinder 3 that accommodates a piston 2 so as to reciprocate is formed, and is attached to a lower portion of the cylinder block 4. It includes a crankcase 6, a cylinder head 8 that is attached to the upper part of the cylinder block 4 and forms a combustion chamber 7 together with the cylinder block 4, and an oil tank 9 that is disposed below the crankcase 6 and stores oil. .

  A crankshaft 10 is rotatably supported at a connecting portion between the cylinder block 4 and the crankcase 6. The crankshaft 10 is connected to the piston 2 via a connecting rod 11, whereby the reciprocating motion of the piston 2 is converted into the rotational motion of the crankshaft 10. And the work tool part is driven by transmitting the rotational motion of the crankshaft 10 to the work tool part (for example, the cutting blade in the brush cutter) of the portable work machine.

  The cylinder head 8 is formed with an intake port 12 for introducing a mixture of fuel and air to the combustion chamber 7 and an exhaust port 13 for discharging combustion gas from the combustion chamber 7. An intake valve 14 is disposed in the intake port 12, and an exhaust valve 15 is disposed in the exhaust port 13. The intake valve 14 and the exhaust valve 15 are driven to open and close by a valve mechanism 20 described below.

  FIG. 2 is a diagram for explaining the components of the valve mechanism 20. As shown in FIGS. 1 and 2, the valve mechanism 20 includes a drive gear 21, a cam gear 22, a cam follower member (first cam follower member 23, second cam follower member 24), and a push rod (first push rod 25). , Second push rod 26) and rocker arms (first rocker arm 27, second rocker arm 28).

  The drive gear 21 is attached to the crankshaft 10 and rotates together with the crankshaft 10. The cam gear 22 has a gear portion 22a in which gear teeth meshing with the drive gear 21 are formed at the periphery, and a cam portion 22b fixed to a side surface of the gear portion 22a. The cam gear 22 is rotatably supported by the first support shaft S1, and rotates around the first support shaft S1 in conjunction with the rotation of the crankshaft 10.

  The first cam follower member 23 and the second cam follower member 24 are supported by a second support shaft S2 disposed above the first support shaft S1 so as to be able to swing (turn). The first cam follower member 23 and the second cam follower member 24 are in contact with the outer peripheral surface (cam surface) of the cam portion 22b of the cam gear 22, and are linked to the rotation of the cam gear 22 (cam portion 22b). Swing (rotate) around S2.

  The first push rod 25 has one end connected to the first cam follower member 23 and the other end connected to one end of the first rocker arm 27, and transmits the swing motion of the first cam follower member 23 to the first rocker arm 27. The second push rod 26 has one end connected to the second cam follower member 24 and the other end connected to one end of the second rocker arm 28, and transmits the swing motion of the second cam follower member 24 to the second rocker arm 28. To do. The other end of the first rocker arm 27 is connected to the intake valve 14, and the other end of the second rocker arm 28 is connected to the exhaust valve 15.

  When the crankshaft 10 rotates, the cam gear 22 is rotationally driven via the drive gear 21. When the cam gear 22 rotates, the first cam follower member 23 and the second cam follower member 24 that are in contact with the outer peripheral surface of the cam portion 22b swing around the second support shaft S2, whereby the first push rod 25 and the second cam follower member 24 are swung. Each push rod 26 moves in the axial direction. As the first push rod 25 moves in the axial direction, the first rocker arm 27 opens and closes the intake valve 14, and as the second push rod 26 moves in the axial direction, the second rocker arm 28 opens and closes the exhaust valve 15. To do. In this manner, the valve mechanism 20 opens and closes the intake valve 14 and the exhaust valve 15.

  Here, the first rocker arm 27 and the second rocker arm 28 are accommodated in a valve operating chamber 17 formed by the cylinder head 8 and the head cover 16 (see FIG. 1). The drive gear 21, the cam gear 22, the first cam follower member 23, and the second cam follower member 24 are accommodated in a valve drive chamber 18 (shown in phantom) provided on the side of the cylinder block 4 (see FIG. 2). ). The valve drive chamber 18 can be formed by, for example, a recess (not shown) formed on the outer surface of the cylinder block 4 and a cover member (not shown) that covers the recess. The 1st push rod 25 and the 2nd push rod 26 are each arrange | positioned in a pair of rod storage chambers 19 and 19 (it shows with an imaginary line). The pair of rod storage chambers 19, 19 also has a function as a communication path that connects the valve operating chamber 17 and the valve drive chamber 18.

  Next, a lubricating structure for lubricating the crankshaft 10 and the valve operating mechanism 20 will be described with reference to FIG. The lubrication structure 30 in the present embodiment includes a first oil passage 31, a second oil passage 32, a communication passage 33 that communicates the oil tank 9 and the valve drive chamber 18, and the pair of rod housing chambers 19 and 19 described above. A suction passage 34 provided in the valve operating chamber 17, a third oil passage 35, a fourth oil passage 36 communicating the valve drive chamber 18 and the crank chamber 5, and a flow rate adjusting passage 37. .

  The first oil passage 31 is a passage for sending the oil in the oil tank 9 to the crank chamber 5. One end (tank side end) of the first oil passage 31 is immersed in the oil stored in the oil tank 9. The other end (end portion on the crank chamber side) of the first oil passage 31 opens into the crank chamber 5 and is opened and closed by the piston 2. Specifically, the crank chamber side end portion of the first oil passage 31 is located below the skirt portion 2a of the piston 2 at the top dead center and below the upper surface of the piston 2 at the bottom dead center. It is arranged (set) to be located. That is, the crank chamber side end portion of the first oil passage 31 is provided at a position that opens while the piston 2 moves from the bottom dead center toward the top dead center. A check valve 31 a for preventing the flow of oil from the crank chamber 5 to the oil tank 9 is provided in the middle of the first oil passage 31. The check valve 31a is configured to open when the pressure in the crank chamber 5 is lower than that in the oil tank 9, in other words, when the crank chamber 5 is in a negative pressure state. That is, the first oil passage 31 sucks up the oil in the oil tank 9 when the piston 2 moves from the bottom dead center toward the top dead center and the inside of the crank chamber 5 becomes a negative pressure state. It is configured to be supplied into the chamber 5. The oil supplied into the crank chamber 5 is mainly agitated by the crankshaft 10 to be misted (oil mist is generated), and thereby the periphery of the crankshaft 10 is lubricated.

  The second oil passage 32 is a passage for sending oil mist generated in the crank chamber 5 and oil staying in the crank chamber 5 to the oil tank 9. One end (crank chamber side end) of the second oil passage 32 is connected to the opening of the bottom of the crank chamber 5, and the other end (tank side end) of the second oil passage 32 is disposed in the oil tank 9. Has been. A reed valve 32 a is provided in the opening at the bottom of the crank chamber 5. The reed valve 32a is configured to open when the pressure in the crank chamber 5 becomes higher than the oil tank 9, in other words, when the crank chamber 5 is in a positive pressure state. That is, the second oil passage 32 is configured so that the oil mist generated in the crank chamber 5 when the piston 2 moves from the top dead center toward the bottom dead center and the crank chamber 5 is in a positive pressure state. The oil staying in the crank chamber 5 is sent to the oil tank 9. Here, the tank side end portion of the second oil passage 32 is set to be positioned above the oil level of the oil stored in the oil tank 9. For this reason, the oil mist generated in the crank chamber 5 is not released into the oil stored in the oil tank 9 but is released toward the oil surface of the oil stored in the oil tank 9. (In other words, it is sprayed on the oil surface). Thereby, it is suppressed that oil bubbles in the oil tank 9, and a part of the released oil mist is liquefied in the oil tank 9.

  The communication path 33 is a path for supplying oil mist in the oil tank 9 to the valve drive chamber 18. One end (tank side end) of the communication path 33 is disposed in the oil tank 9, and the other end (valve drive chamber side end) of the communication path 33 is open to the bottom of the valve drive chamber 18. The tank side end portion of the communication passage 33 is located above the tank side end portion of the second oil passage 32 in the oil tank 9. For this reason, the oil mist discharged from the tank side end of the second oil passage 32 is prevented from flowing directly into the communication passage 33. Further, as described above, a part of the oil mist discharged from the tank side end portion of the second oil passage 32 is liquefied in the oil tank 9, so that it has a lower concentration than the oil mist in the crank chamber 5. Oil mist flows into the communication path 33. The oil mist flowing into the communication path 33 is supplied to the valve drive chamber 18 and further supplied to the valve operating chamber 17 via the rod accommodating chambers 19 and 19. Thereby, each element which comprises the valve operating mechanism 20 is lubricated.

  The suction passage 34 is a passage for sucking oil staying in the valve operating chamber 17. At least one suction hole 34 a is formed in the suction passage 34, and at least one suction pipe 34 b that opens near the inner bottom surface of the valve operating chamber 17 is connected to the suction passage 34.

  The third oil passage 35 is a passage for sending the oil sucked into the suction passage 34 into the crank chamber 5. One end (suction passage side end) of the third oil passage 35 is connected to the suction passage 34, and the other end (crank chamber side end) of the third oil passage 35 opens into the crank chamber 5. The crank chamber side end portion of the third oil passage 35 is located below the skirt portion 2a of the piston 2 at the top dead center and is bottom dead like the crank chamber side end portion of the first oil passage 31. It is arranged (set) so as to be positioned below the upper surface of the piston 2 at the point.

  Therefore, when the piston 2 moves from the bottom dead center toward the top dead center and the inside of the crank chamber 5 is in a negative pressure state, the oil staying in the valve operating chamber 17 is sucked into the suction holes 34a and / or sucked. The air is sucked into the suction passage 34 via the pipe 34 b and then sent to the crank chamber 5 via the third oil passage 35. The oil sent to the crank chamber 5 is misted in the crank chamber 5 or stays in the crank chamber 5 and is sent to the oil tank 9 through the second oil passage 32.

  The fourth oil passage 36 is a passage for returning the oil staying in the valve drive chamber 18 into the crank chamber 5. One end (valve drive chamber side end) of the fourth oil passage 36 is open near the bottom of the valve drive chamber 18, and the other end (crank chamber side end) of the fourth oil passage 36 is the first oil passage 31. Like the crank chamber side end portion and the third oil passage 35 of the crank chamber side end portion, the crank chamber side end portion is open in the crank chamber 5. That is, the fourth oil passage 36 is configured to send the oil staying in the valve drive chamber 18 to the crank chamber 5 when the crank chamber 5 is in a negative pressure state. Note that the passage cross-sectional area of the fourth oil passage 36 is very small compared to the passage cross-sectional area of the second oil passage 32, and when the crank chamber 5 is in a positive pressure state, the crank oil chamber 5 extends to the fourth oil passage 36. The oil is hardly sent to the valve drive chamber 18 via.

  The flow rate adjusting passage 37 connects the valve drive chamber 18 and the first oil passage 31, and is supplied into the crank chamber 5 through the first oil passage 31 by sucking air in the valve drive chamber 18. Adjust the oil flow. The flow rate adjusting passage 37 is provided with a flow restrictor 37 a, and the amount of air sucked from the valve drive chamber 18 by the flow restrictor 37 a, and consequently, is supplied into the crank chamber 5 through the first oil passage 31. The oil flow is adjusted. The flow restrictor 37 a may be configured separately from the flow rate adjusting passage 37 or may be configured as a part of the flow rate adjusting passage 37.

  Next, a blow-by gas processing apparatus for introducing blow-by gas leaking from the combustion chamber 7 into the intake system of the engine 1 will be described with reference to FIG. In the present embodiment, the blow-by gas processing device 40 separates the oil mist from the blow-by gas extracted from the valve operating chamber 17 (that is, the blow-by gas including the oil mist), and the blow-by gas after the oil mist separation is taken into the intake system. It is configured to return to The blow-by gas processing device 40 includes an extraction passage 41, an oil separator 50, a blow-by gas passage 42, and an oil return passage 43.

  The extraction passage 41 is a passage for extracting blow-by gas including the oil mist from the valve operating chamber 17 and guiding it to the oil separator 50. One end of the extraction passage 41 opens into the valve operating chamber 17, and the other end of the extraction passage 41 is connected to the blow-by gas inlet 51 of the oil separator 50.

  The oil separator 50 is a device that separates oil mist from blow-by gas containing the oil mist that has flowed in through the blow-by gas inlet 51. The blow-by gas after the oil mist separation flows out from the blow-by gas outlet 52, and the separated oil mist is liquefied and stored as liquid oil in the oil separator 50, and then flows out from the oil outlet 53. To do. Although illustration is omitted here, the oil separator 50 may be provided integrally with an air cleaner that removes foreign matter from the air sucked into the engine 1 or an insulator that blocks heat from the cylinder. Further, the state shown in FIG. 3 is a state when the oil separator 50 is upright.

  The blow-by gas passage 42 is a passage for guiding the blow-by gas after the oil mist separation to the intake system. One end of the blowby gas passage 42 is connected to a blowby gas outlet 52 of the oil separator 50, and the other end of the blowby gas passage 42 is connected to an intake passage (not shown) of the engine 1. When the oil separator 50 is provided integrally with the air cleaner, the blow-by gas passage 42 is also provided integrally with the air cleaner.

  The oil return passage 43 is a passage for guiding (returning) the liquid oil stored in the oil separator 50 to the crank chamber 5. In the present embodiment, one end of the oil return passage 43 is connected to the oil outlet 53 of the oil separator 50, and the other end of the oil return passage 43 is closer to the crank chamber 5 than the check valve 31 a of the first oil passage 31. It is connected to the part. However, the present invention is not limited to this, and the oil return passage 43 may not be connected to the first oil passage 31.

  Next, the configuration of the oil separator 50 will be specifically described with reference to FIGS. FIG. 4 shows the oil separator 50 in the upright state. 4A is a plan view of the oil separator 50, FIG. 4B is a front view of the oil separator 50, and FIG. 4C is a side view of the oil separator 50. 5 and 6 are exploded perspective views of the oil separator 50. FIG. 7 is an AA cross-sectional enlarged view of FIG. 4A, FIG. 8 is a BB cross-sectional enlarged view of FIG. 4A, and FIG. 9 is a CC cross-sectional enlarged view of FIG. 4A. FIG. FIG. 10 is a DD cross-sectional enlarged view of FIG. 11 is a cross-sectional view taken along line EE in FIG. In the following description, “up and down or height” refers to the top and bottom or height of the oil separator 50 in an upright state.

  In the present embodiment, the oil separator 50 includes a housing 54, an inner case 55 accommodated in the housing 54, and a cover 56 attached to the upper part of the housing 54.

  The housing 54 is formed in a rectangular box shape with an upper opening, and the oil outlet 53 described above is provided on the bottom surface. The oil outlet portion 53 is formed as a tubular body that protrudes downward from a substantially central portion of the bottom surface of the housing 54, and has a large-diameter pipe portion 53 a that opens to the inner bottom surface of the housing 54, and the other end of the large-diameter pipe portion 53 a. And a small-diameter pipe portion 53b continuous on the side. The one end of the oil return passage 43 is connected to the small diameter pipe portion 53 b of the oil outlet portion 53.

  A check valve 57 for preventing the backflow of the liquid oil is mounted in the conduit of the large-diameter pipe 53a of the oil outlet 53 (see FIGS. 5 to 8). The check valve 57 is configured to open when the pressure in the crank chamber 5 is lower than that in the housing 54, that is, when the crank chamber 5 is in a negative pressure state. In the present embodiment, the inner bottom surface of the housing 54 is formed as a substantially flat surface, but the present invention is not limited to this. For example, the inner bottom surface of the housing 54 may be formed so as to be gradually lowered toward the one end (that is, the opening) of the large-diameter pipe portion 53a of the oil outlet portion 53 (for example, in a “mortar shape”). Good.

  The inner case 55 is formed in a rectangular box shape having an upper opening and is accommodated in the housing 54. The inside of the inner case 55 constitutes a separation chamber that separates the oil mist from the blowby gas containing the oil mist. The bottom surface of the inner case 55 has a shape corresponding to the inner bottom surface of the housing 54. Further, the inner case 55 is formed so that the upper end surface thereof is substantially flush with the upper end surface of the housing 54 when accommodated in the housing 54 (see FIGS. 7 and 8). The four corners (including the vicinity thereof) of the upper end surface of the inner case 55 are provided with recesses 551 lower than the other parts (see FIGS. 6 and 9).

  The inside of the inner case 55 is partitioned into a first space 553 and a second space 554 wider than the first space 553 by a first wall portion 552 standing on the inner bottom surface of the inner case 55 (FIG. 6). reference). The first wall portion 552 is formed in a substantially L shape (or a substantially inverted L shape) in plan view (see FIG. 9). The front end surface (upper end surface) of the first wall portion 552 is located at a position slightly lower than the upper end surface of the inner case 55, and both ends of the first wall portion 552 are respectively adjacent to the inner case 55. Connected to the side. Further, a truncated cone-shaped convex portion 555 is provided at a bottom portion of the first space 553, that is, a portion located in the first space 553 on the inner bottom surface of the inner case 55 (see FIG. 7).

  An X-shaped groove 556 corresponding to the diagonal line is formed on the bottom surface of the inner case 55 (see FIG. 5). The X-shaped groove portion 556 cooperates with the inner bottom surface of the housing 54 when the inner case 55 is accommodated in the housing 54, and has a substantially X-shaped first portion on the inner bottom surface of the housing 54. A passage-like space 58 is formed (see FIGS. 7, 8, and 11). In addition, a plurality of through holes 557 having a relatively small diameter communicating with the inside and outside of the inner case 55 are formed at the bottom of the groove portion 556. In the present embodiment, four through holes 557 are formed, and each through hole 557 is located in the vicinity of one of the four corners of the inner bottom surface of the inner case 55 (see FIG. 9).

  In the inner case 55, each corner (side ridge) formed by two adjacent outer side surfaces is chamfered, and ribs 558 extending in the vertical direction are formed on both sides of each chamfer. (See FIGS. 5 and 6). When the inner case 55 is accommodated in the housing 54, the leading end portion of each rib 558 abuts on the corresponding inner side surface of the housing 54, and thus, between the housing 54 and the inner case 55, specifically, A second passage-like space that extends in the vertical direction and communicates with the above-described substantially X-shaped first passage-like space 58 at a position corresponding to each side ridge portion of the inner case 55 and outside the inner case 55. 59 is formed (see FIG. 9).

  The cover 56 is formed so as to cover the upper portion of the housing 54. When the cover 56 is attached to the housing 54, the inner surface of the cover 56 comes into contact with the upper end surface of the housing 54 and the upper end surface of the inner case 55, whereby the upper surface opening of the housing main body 541 and the upper surface opening of the inner case 55 are formed. Blocked. However, the inside of the inner case 55 communicates with each of the above-described four second passage-like spaces 59 located outside the inner case 55 by four concave portions 551 provided on the upper end surface of the inner case 55. (See FIG. 11). Further, a gap G1 is formed between the inner surface of the cover 56 and the front end surface (upper end surface) of the first wall portion 552 of the inner case 55 (see FIGS. 7 and 8).

  Further, the cover 56 integrally includes the blow-by gas inlet 51 and the blow-by gas outlet 52 described above. The blow-by gas inlet portion 51 and the blow-by gas outlet portion 52 are formed as mutually parallel tubular bodies extending in the vertical direction, and communicate the outside with the inside of the inner case 55 as the separation chamber.

  The blow-by gas inlet 51 includes an outer tube 51 a that protrudes from the outer surface of the cover 56 and an inner tube 51 b that protrudes from the inner surface of the cover 56. In the middle of the pipe line of the inner pipe part 51b, a throttle part 51c for reducing the pipe line area toward the tip side is provided, and the pipe line area on the tip side of the inner pipe part 51b is equal to that of the inner pipe part 51b. It is smaller than the pipe area of the portion on the inner surface side of the cover 56 and the pipe area of the outer pipe portion 51a. The blow-by gas outlet portion 52 also has an outer tube portion 52a protruding from the outer surface of the cover 56 and an inner tube portion 52b protruding from the inner surface of the cover 56 (see FIG. 7).

  When the cover 56 is attached to the housing 54, the inner pipe portion 51 b of the blow-by gas inlet 51 is accommodated in the first space 553 of the inner case 55, and the inner pipe portion 52 b of the blow-by gas outlet 52 is connected to the inner case 55. It is accommodated in the second space 554. The tip of the inner tube portion 51 b of the blow-by gas inlet portion 51 is disposed immediately above the truncated cone-shaped convex portion 555 provided at the bottom portion of the first space 553. That is, the inner pipe portion 51 b of the blow-by gas inlet portion 51 extends toward the convex portion 555 inside the inner case 55. The tip of the inner tube portion 52 b of the blowby gas outlet portion 52 is disposed at a position higher than the tip of the inner tube portion 51 b of the blowby gas inlet portion 51.

  A second wall portion 561 is erected on the inner surface of the cover 56 (see FIGS. 5 and 7). When the cover 56 is attached to the housing 54, the second wall portion 561 cooperates with the inner side surface of the inner case 55 to enter the inner space of the blow-by gas outlet portion 52 in the second space 554 of the inner case 55. A third space 562 that accommodates the portion 52b is formed (see FIG. 9). The third space 562 corresponds to a “space part” in the present invention. In the present embodiment, the second wall portion 561 has a substantially point-symmetric shape in plan view with respect to the first wall portion 552 formed in the inner case 55. Then, both ends of the second wall portion 561 come into contact with adjacent inner side surfaces of the inner case 55 where both ends of the first wall portion 552 are not connected when the cover 56 is attached to the housing 54 (see FIG. 9). Further, a gap G2 is formed between the front end surface (lower end surface) of the second wall portion 561 and the inner bottom surface of the inner case 55 (see FIGS. 7 and 11).

  Here, in the inner case 55, that is, in the separation chamber of the oil separator 50, the first space 553 that houses the inner pipe part 51 b of the blow-by gas inlet part 51 and the inner pipe part 52 b of the blow-by gas outlet part 52 are housed. The third space 562 communicates with the gap G1, the inter-wall space between the first wall portion 552 and the second wall portion 561 (= second space 554-third space 562), and the gap G2. (See FIG. 7). In addition, the separation chamber of the oil separator 50 communicates with the oil outlet portion 53 through the four through holes 557 and the first passage-like space 58, and the four recesses 551 and the four second passage-like spaces 59. In addition, the oil outlet portion 53 communicates with the first passage-shaped space 58.

  Next, the operation of the oil separator 50 having the above configuration will be described. In the valve operating chamber 17, there are blow-by gas leaking from the combustion chamber 7 and supplied oil mist. The separation chamber of the oil separator 50 communicates with the intake passage of the engine 1 via a blowby gas passage 42 connected to the blowby gas outlet portion 52. Therefore, the negative pressure generated in the intake passage acts on the separation chamber, whereby blow-by gas and oil mist in the valve operating chamber 17, that is, blow-by gas containing the oil mist, passes through the extraction passage 41. Then, it flows into the blow-by gas inlet 51 (see FIG. 7).

  The blow-by gas containing the oil mist flowing into the blow-by gas inlet 51 collides with the convex portion 555 in the first space 553 of the separation chamber. The oil mist is separated from the blow-by gas containing the oil mist by the collision with the convex portion 555. That is, oil mist adheres to the convex portion 555, liquefies, and is stored in the separation chamber. Here, in this embodiment, the throttle part 51c is provided in the inner pipe part 51b of the blow-by gas inlet part 51, and the blow-by gas containing the oil mist is accelerated and momentum when passing through the throttle part 51c. It often collides with the convex portion 555. For this reason, the oil mist is more effectively separated from the blow-by gas including the oil mist due to the collision with the convex portion 555.

  The blow-by gas after colliding with the convex portion 555 rises in the first space 553 and flows out of the first space 553 through the gap G1. The blow-by gas that has flowed out of the first space 553 passes while descending the inter-wall space between the first wall portion 552 and the second wall portion 561, and flows into the third space 562 through the gap G2. In other words, the blow-by gas after colliding with the convex portion 555 flows into the third space 562 after passing through the labyrinth structure passage portion 60 having a plurality of bent portions and formed in a labyrinth shape (FIG. 7). reference). In the present embodiment, the labyrinth structure passage portion 60 is formed by a first wall portion 552 provided in the inner case 55 and a second wall portion 561 provided in the cover 56, and is formed in an upper portion of the separation chamber. And a bent portion positioned at a lower portion of the separation chamber.

  The blow-by gas after colliding with the convex portion 555 passes through the passage portion 60 of the labyrinth structure while changing its traveling direction. At this time, oil mist contained in the blow-by gas after colliding with the convex portion 555 is separated mainly by inertia. That is, the oil mist adheres to the wall surface of the passage portion 60 having the labyrinth structure, is liquefied, and is stored in the separation chamber. Here, in this embodiment, the passage part 60 of the labyrinth structure is formed so that the blow-by gas after colliding with the convex part 555 is raised and then lowered so that the oil mist can be separated more effectively. Done.

  In this way, most of the oil mist contained in the blow-by gas including the oil mist flowing from the blow-by gas inlet 51 is separated and flows into the third space 562 almost as a blow-by gas. The blow-by gas in the third space 562 flows out from the blow-by gas outlet 52 and is guided to the intake passage through the blow-by gas passage 42. Here, in the present embodiment, the blowby gas that has passed through the passage portion 60 of the labyrinth structure flows into the lower portion of the third space 562 through the narrow gap G2 of the passage area, and the blowby gas outlet portion 52 The distal end portion of the inner tube portion 52b is provided at a position higher than the gap G2 (that is, the inflow portion) (see FIG. 7). For this reason, even if the oil mist is contained in the blow-by gas flowing into the third space 562, the oil mist is prevented from flowing out from the blow-by gas outlet 52.

  Further, the separation chamber of the oil separator 50 communicates with the oil outlet portion 53 through the four through holes 557 and the first passage-like space 58, and has four recesses 551 and four second passage-like spaces. 59 and the first outlet space 58 communicate with the oil outlet 53. The oil outlet 53 communicates with the crank chamber 5 via the oil return passage 43 and the first oil passage 31, and the oil outlet 53 is reversely opened when the inside of the crank chamber 5 is in a negative pressure state. A stop valve 57 is provided.

  Therefore, when the oil separator 50 is in the state shown in FIG. 4, the liquid oil stored in the separation chamber has a negative pressure in the crank chamber 5 as the piston 2 moves from the bottom dead center toward the top dead center. When the state is reached, the air is sucked through at least one of the four through holes 557, and then flows out from the oil outlet 53 through the first passage-like space 58, and the oil return passage 43 and the first oil passage 31. To be sent to the crank chamber 5.

  On the other hand, when the oil separator 50 is turned upside down from the state shown in FIG. 4, the liquid oil stored in the separation chamber is at least one of the four recesses 551 when the crank chamber 5 is in a negative pressure state. And then flows out from the oil outlet 53 through at least one of the four second passage-like spaces 59 and the first passage-like space 58, and passes through the oil return passage 43 and the first oil passage 31. To the crank chamber 5.

  Here, in the present embodiment, through holes 557 are provided in the vicinity of each of the four corners of the inner bottom surface of the inner case 55 (that is, the bottom portion in the separation chamber). In addition, a recess 551 is provided in each of the four corners of the upper end surface of the inner case 55 (that is, the upper part in the separation chamber). Therefore, even when the oil separator 50 changes from the upright state to various postures according to the usage state of the portable work machine, at least one liquid oil stored in the separation chamber is present. Suction can be performed through the through hole 557 and / or at least one recess 551. In other words, an oil separator capable of sucking the liquid oil stored in the separation chamber in a multi-position and sending it to the crank chamber 5 can be realized.

  Further, in the present embodiment, a substantially X-shaped first passage-like space 58 is formed on the inner bottom surface of the housing 54, and the oil outlet portion 53 corresponds to the intersection of the first passage-like space 58. In the position. Therefore, a plurality of liquid oils stored in the separation chamber by one oil outlet 53, specifically, four through holes 557 in the bottom of the separation chamber and four recesses 551 in the upper portion of the separation chamber. And the sucked liquid oil is collected and flows out from one oil outlet 53. Therefore, only one oil return passage 43 is required, and the installation space for the oil separator 50 is reduced, and the cost increase associated with the installation of the oil separator 50 is suppressed.

  Here, the threaded portion is formed on the outer peripheral surface of the small diameter pipe portion 53b of the oil outlet portion 53, and the corresponding threaded portion is formed on the cylinder block 4 or the like, thereby directly fixing the oil separator 50 to the cylinder block 4 or the like. It is also possible to do. In this case, since the oil return passage 43 can be omitted, the installation space for the oil separator 50 is further reduced, and the cost increase associated with the installation of the oil separator 50 is further suppressed.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, Of course, a further deformation | transformation and change are possible based on the technical idea of this invention. is there.

  For example, instead of the oil separator 50 described above, an oil separator 500 as shown in FIGS. 12 to 14 may be used. 12 and 13 are exploded perspective views of oil separator 500 (corresponding to FIGS. 5 and 6 described above), and FIG. 14 is a plan sectional view of oil separator 500 (corresponding to FIG. 10 described above). ). 12-14, the same code | symbol is attached | subjected about the component which is common in the oil separator 50, and the description is abbreviate | omitted.

  The oil separator 500 includes a housing 54, an inner case 501 accommodated in the housing 54, and a cover 502 attached to the upper part of the housing 54. The basic configuration of the oil separator 500 is substantially the same as that of the oil separator 50, but mainly differs in the following points.

  That is, as described above, in the oil separator 50, the first space 553 that accommodates the inner pipe portion 51 b of the blow-by gas inlet portion 51 is formed by the inner wall of the inner case 55 and the first wall portion 552 provided in the inner case 55. A third space 562 that is formed and accommodates the inner pipe portion 52b of the blow-by gas outlet portion 52 is formed by the inner wall of the inner case 55 and the second wall portion 561 provided on the cover 56 (see FIG. 10). The blowby gas after colliding with the convex portion 555 in the first space 553 is formed by the first wall portion 552 provided in the inner case 55 and the second wall portion 561 provided in the cover 56. It passes through the passage portion 60 of the labyrinth structure and flows into the third space 562 (see FIG. 7).

  On the other hand, in the oil separator 500, two wall portions (inner case side wall portions) 503 and 504 are provided inside the inner case 501 with a space therebetween. The first space 505 that accommodates the inner pipe portion 51b of the blow-by gas inlet portion 51 is formed by one inner case side wall portion 503 and the inner wall of the inner case 501, and the inner pipe portion 52b of the blow-by gas outlet portion 52 The third space 506 to be accommodated is formed by the other inner case side wall 504 and the inner wall of the inner case 501. In the oil separator 500, blow-by gas after colliding with a convex portion (not shown) in the first space 505 is transferred to the two inner case side walls 503 and 504 provided in the inner case 501 and the cover 502. It passes through the passage portion of the labyrinth structure formed by the provided wall portion (cover side wall portion) 507 and flows into the third space 506. Here, slits 503 a and 504 a extending in the vertical direction are formed in the two inner case side walls 503 and 504 provided in the inner case 501. The cover side wall portion 507 provided on the cover 502 is disposed between the two inner case side wall portions 503 and 504 provided on the inner case 501 when the cover 502 is attached to the housing 54.

  Specifically, in the oil separator 500, blow-by gas after colliding with the convex portion in the first space 505 is the one inner case as shown by an arrow in FIG. 15 which is an enlarged view of FIG. It flows out of the first space 505 through a slit 503a formed in the side wall portion 503. The blow-by gas flowing out from the first space 505 moves in the space between the one inner case side wall portion 503 and the cover side wall portion 507, and a gap G3 between the end portion of the cover side wall portion 507 and the inner wall of the inner case 501. , G4 to move to a space between the cover side wall portion 507 and the other inner case side wall portion 504, and then the third space via a slit 504a formed in the other inner case side wall portion 504. Flow into 506. Thus, also in the oil separator 500, the blowby gas after colliding with the convex portion in the first space 505 passes through the passage portion of the labyrinth structure having a plurality of bent portions and formed in a labyrinth shape. Then, it flows into the third space 506. For this reason, also in the oil separator 500, when the blow-by gas after colliding with the convex part passes through the passage part of the labyrinth structure, the oil mist contained therein is effectively separated.

  In addition, it is possible to replace a part of the configuration of the oil separator 50 in the above-described embodiment (for example, the separation chamber) with another configuration. For example, since the portable work machine is used in various postures, the oil separator must be compatible with multi-positions. Specifically, the oil mist (liquid oil mist) separated regardless of the posture of the oil separator. ) Can be sent to the crankcase. When paying particular attention to this point, the separation chamber of the oil separator is not necessarily required to have the configuration of the above-described embodiment. That is, the separation chamber of the oil separator is not particularly limited as long as the oil mist can be separated from the blow-by gas containing the oil mist. For example, in the above-described embodiment, the separation chamber of the oil separator 50 flows out from the blow-by gas outlet 52 after the blow-by gas including the oil mist flowing from the blow-by gas inlet 51 passes through a filter (mesh) or the like. It may be configured to. In addition, about structures other than the said separation chamber, it can be set as the structure in the above-mentioned embodiment. The configuration of such an engine oil separator is exemplified below.

  An oil separator for an engine includes a blow-by gas inlet portion into which blow-by gas including oil mist flows, a separation chamber that separates oil mist from the blow-by gas including oil mist flowing in through the blow-by gas inlet portion, and an oil A blow-by gas outlet part from which blow-by gas after mist separation flows out and an oil outlet part from which liquid oil flows out are included. The engine oil separator is configured such that liquid oil in the separation chamber is sucked at a plurality of locations, and the sucked liquid oil is collected and flows out from the oil outlet portion. In this case, it is preferable that the liquid oil in the separation chamber is sucked at a plurality of locations in the upper portion of the separation chamber and a plurality of locations in the bottom (lower portion) of the separation chamber.

  According to such an engine oil separator, the oil mist separated from the blow-by gas containing the oil mist, regardless of the posture of the engine oil separator, etc., by communicating the oil outlet portion into the crank chamber, That is, liquid oil in the separation chamber can be sent to the crank chamber.

  DESCRIPTION OF SYMBOLS 40 ... Blow-by gas processing apparatus, 41 ... Extraction passage, 42 ... Blow-by gas passage, 43 ... Oil return passage, 50, 500 ... Oil separator, 51 ... Blow-by gas inlet part, 51a ... Outer pipe part of blow-by gas inlet part, 51b ... inner pipe part of blow-by gas inlet part, 51c ... throttle part, 52 ... blow-by gas outlet part, 52a ... outer pipe part of blow-by gas outlet part, 52b ... inner pipe part of blow-by gas outlet part, 53 ... oil outlet part, 53a ... Large diameter pipe part of oil outlet part, 53b ... Small diameter pipe part of oil outlet part, 54 ... Housing, 55,501 ... Inner case, 56,502 ... Cover, 57 ... Check valve, 58 ... First passage shape Space, 59 ... second passage-like space, 60 ... passage part of labyrinth structure, 503, 504 ... wall part (inner case side wall part), 507 ... wall part (capacity) -Sidewall portion) 551 ... concave portion, 552 ... first wall portion (inner case side wall portion), 553, 505 ... first space, 554 ... second space, 555 ... convex portion (collision portion), 556 ... X-shaped Groove, 557 ... through hole, 558 ... rib, 561 ... second wall (cover side wall), 562,506 ... third space (space)

Claims (11)

A blow-by gas inlet section into which blow-by gas containing oil mist flows,
A separation chamber for separating oil mist from blow-by gas containing the oil mist flowing in via the blow-by gas inlet;
A blow-by gas outlet from which blow-by gas flows out after oil mist separation;
An oil outlet through which liquid oil flows,
Including
The separation chamber is
A collision part where a blow-by gas containing the oil mist flowing in via the blow-by gas inlet part collides;
A passage part of a labyrinth structure having a plurality of bent parts, through which blow-by gas after colliding with the collision part passes,
A space part into which blow-by gas flows after passing through the passage part of the labyrinth structure;
Have
Blow-by gas in the space flows out from the blow-by gas outlet.
Oil separator for engine.   The blow-by gas inlet has an inner pipe extending in the separation chamber toward the collision part, and the inner pipe of the blow-by gas inlet is provided with a throttle for reducing the pipe area. The oil separator for engines according to claim 1. The blow-by gas outlet part has an inner pipe part located in the space part of the separation chamber,
The tip part of the inner tube part of the blow-by gas outlet part is arranged at a position higher than the inflow part into which the blow-by gas after passing through the passage part of the labyrinth structure flows into the space part. Or the oil separator for engines of 2.   The engine oil separator according to any one of claims 1 to 3, wherein the blow-by gas after the oil mist separation flows out in a direction opposite to an inflow direction of the blow-by gas including the oil mist.   5. The liquid oil in the separation chamber is sucked from a plurality of locations, and the sucked liquid oil is collected and flows out from the oil outlet portion. 6. Oil separator for engines.   The engine oil separator according to claim 5, wherein the liquid oil in the separation chamber is configured to be sucked from a plurality of locations at the top of the separation chamber and a plurality of locations at the bottom of the separation chamber. A housing formed in a box shape with an upper surface opening, and having the oil outlet portion on the bottom surface;
An inner case which is formed in a box shape having an upper surface opening and is housed in the housing and the inside of which forms the separation chamber;
A cover having the blow-by gas inlet portion and the blow-by gas outlet portion, and closing the upper surface opening of the housing and the upper surface opening of the inner case;
The oil separator for engines according to any one of claims 1 to 6 containing.   The engine oil separator according to claim 7, wherein the passage portion of the labyrinth structure is formed by an inner case side wall portion provided in the inner case and a cover side wall portion provided in the cover.   The engine oil separator according to claim 7 or 8, wherein the blow-by gas inlet and the blow-by gas outlet are formed as tubular bodies parallel to each other. The inside of the inner case as the separation chamber communicates with the oil outlet through a plurality of through holes formed in the bottom of the inner case and a first passage-like space formed on the inner bottom surface of the housing. And a plurality of recesses formed in the upper part of the inner case, a plurality of second passage-like spaces formed between the housing and the inner case and extending in the vertical direction, and the first passage-like spaces. Communicating with the oil outlet,
The oil separator for engines according to any one of claims 7 to 9. The housing and the inner case are formed in a rectangular box shape,
Each of the plurality of through holes is disposed in the vicinity of a corner of the inner bottom surface of the inner case,
The first passage-shaped space is formed in a substantially X shape by an X-shaped groove portion formed diagonally on the bottom surface of the inner case and the inner bottom surface of the housing,
Each of the plurality of recesses is disposed in the vicinity of the corner of the upper end surface of the inner case,
Each of the plurality of second passage-like spaces is disposed in the vicinity of a side ridge portion of the inner case,
The oil outlet portion is disposed at a position corresponding to the intersection of the first passage-shaped space formed in a substantially X shape.
The oil separator for engines according to claim 10.