JP4506656B2 - Oil mist separator and cylinder head cover - Google Patents

Description

  The present invention relates to an oil mist separator provided on a blow-by gas passage that communicates an engine crank chamber and an intake passage, and a cylinder head cover including the oil mist separator.

  Conventionally, as this type of oil mist separator, for example, there is one described in Patent Document 1. As shown in FIGS. 9A to 9C, the oil mist separator includes a separation chamber 50 arranged on the blow-by gas passage, and a valve mechanism 51 is provided below the separation chamber 50. It has been. The separation chamber 50 is communicated with the crank chamber side via a gas inlet 50a, and is communicated with an intake manifold via a gas discharge port 50b to which a PCV (Positive Crankcase Ventilation) valve (not shown) is connected. The oil passage of the valve mechanism 51 is communicated with the lower end of the separation chamber 50 via an oil introduction port 52 located at the upper portion thereof, and is communicated with the crank chamber side via an oil discharge port 53 located at the lower portion. . A valve seat 55 is formed in a valve chamber 54 formed between the oil introduction port 52 and the oil discharge port 53, and a valve body 56 that can be brought into contact with and separated from the valve seat 55 is accommodated. The valve body 56 is disposed between the first valve portion 57 disposed between the oil introduction port 52 and the valve seat 55, and between the valve seat 55 and the oil discharge port 53. The second valve portion 59 is connected through a rod 58.

  When the crank chamber pressure becomes higher than the intake manifold pressure in the no-load operation state of the engine, as shown in FIG. 9A, the valve body 56 is urged upward by the differential pressure. For this reason, the first valve portion 57 is separated from the upper surface of the valve seat 55 and the second valve portion 59 is in contact with the lower surface of the valve seat 55. In this state, oil is centrifuged from blow-by gas flowing from the crank chamber into the separation chamber 50 through a blow-by gas passage (not shown), and the centrifuged oil is accumulated in the valve chamber 54.

  When the engine is switched from the no-load operation state to the low load operation state, the intake manifold pressure and the crank chamber pressure become substantially equal, as shown in FIG. Both the two valve portions 59 are held at positions where they do not contact the valve seat 55. In this state, the oil accumulated in the valve chamber 54 is returned from the oil discharge port 53 to the crank chamber side.

Further, when the engine is in a high load operation state and the intake manifold pressure becomes higher than the crank chamber pressure, the valve body 56 is biased downward by the differential pressure, as shown in FIG. Then, the first valve portion 57 is pressed against the upper surface of the valve seat 55 and the second valve portion 59 is separated from the lower surface of the valve seat 55. At this time, the separation chamber 50 communicates with the oil discharge port 53 of the valve chamber 54 through a notch 60 provided on the upper surface of the valve seat 55. In this state, oil is centrifuged from blow-by gas flowing from the crank chamber into the separation chamber, and the centrifuged oil is returned from the valve chamber 54 to the crank chamber side through the notch 60.
JP 2003-13723 A

  By the way, sludge may adhere to the surfaces of the valve seat 55 and the valve body 56. In such a case, the valve body 56 pressed against the valve seat 55 in a high-load operation state of the engine may be stuck to the valve seat 55 by sludge and may not move. Therefore, in this case, even when the intake manifold pressure becomes lower than the crank chamber pressure in the no-load operation state or the low-load operation state of the engine, the valve body 56 does not leave the valve seat 55, and the separation chamber 50 passes only through the notch 60. To communicate with the crank chamber. Therefore, the oil accumulated in the valve chamber 54 is returned to the crank chamber side little by little only from the notch 60, so that the oil centrifuged from the blow-by gas with the operation of the engine overflows from the valve chamber 54. In some cases, the separation chamber 50 may accumulate. Then, there was a problem that the oil in the separation chamber 50 was carried to the intake manifold side by blow-by gas.

  An object of the present invention is to provide an oil mist separator that can more reliably return oil separated from blow-by gas to the engine side, and a cylinder head cover including the oil mist separator.

In order to achieve the above object, an invention according to claim 1 is an oil mist separator provided on a blow-by gas passage that communicates an engine crank chamber and an intake passage, and is a blow-by introduced from the crank chamber. A separation portion that separates oil from the gas; and a check valve that allows oil to be discharged from the separation portion to the crank chamber side and restricts the inflow of gas from the crank chamber side to the separation portion side. The stop valve includes a valve body that is displaced by a differential pressure between the intake side pressure and the crank chamber pressure, and from the crank chamber side in a valve closing state in which the valve body abuts against a valve seat provided between the stop portion and the separation portion. In addition to restricting the flow of blow-by gas to the separation part side, the valve element is configured to discharge oil from the separation part to the crank chamber side when the valve body is open from the valve seat. In Le mist separator, between the valve body and the valve chamber wall in the open state is provided with means for retaining the separated state the valve element against the valve chamber walls, and said valve body, said valve body The oil outlet of the accommodated valve chamber is configured such that a part of the oil outlet is always open, the valve body and the oil outlet are each formed in a star shape having three or more protrusions, and the valve The number of projecting portions of the body is different from the number of projecting portions of the oil outlet .

The invention described in claim 2 is characterized in that, in addition to the invention described in claim 1, the means is a plurality of sharp legs .

The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2 , the abutting portion of the valve body contacting and separating from the valve seat has a hemispherical shape.
According to a fourth aspect of the present invention, in the third aspect of the present invention, the contact portion is hollow.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, oil discharged from the separation portion is disposed between the separation portion and the check valve. It is characterized by having a reservoir for storing.

A sixth aspect of the present invention is a cylinder formed of a synthetic resin, including the oil mist separator according to any one of the first to fifth aspects, and integrally formed with the housing of the separation portion. It is a head cover.

In a seventh aspect of the present invention, in the sixth aspect of the present invention, the separation portion includes a conical separation chamber that swirls blow-by gas introduced from the crank chamber, the axis of which is inclined with respect to the vertical direction. It is characterized by being.

  In the oil mist separator according to the present invention, the check valve is held away from the valve chamber wall when the check valve is open corresponding to the intake manifold pressure being higher than the crank chamber pressure. Is done. For this reason, even if sludge adheres to the valve chamber wall or the valve body, the valve body does not adhere to the valve chamber wall in the valve open state in which oil is discharged from the separation chamber to the crank chamber side. When the crank chamber pressure becomes higher than the intake manifold pressure, the valve body is easily separated from the valve chamber wall to be in a closed state. As a result, the communication between the separation chamber and the check valve is more reliably blocked, so that gas containing blow-by gas is not introduced from the crank chamber side to the separation chamber side via the check valve. Accordingly, oil is not returned from the valve chamber of the check valve to the separation chamber when the engine is in a low load operation state. In addition, an oil passage that communicates the valve chamber and the oil outlet is formed between the valve body and the valve chamber wall in the open state of the check valve. Therefore, oil is more reliably discharged from the check valve to the crank chamber side when the engine is in a low load operation state. Therefore, according to the present invention, the oil separated from the blow-by gas can be more reliably returned to the engine side.

  Further, it is preferable that the valve body and the oil outlet of the valve chamber in which the valve body is accommodated are configured such that a part of the oil outlet is always opened. In this case, in the open state of the check valve, an oil passage that extends linearly in the displacement direction of the valve body is formed by the open portion of the oil outlet. For this reason, the flow path resistance when oil is discharged from the valve chamber to the crank chamber side is reduced. Accordingly, when the engine is in a low load operation state, the oil is more smoothly discharged from the valve chamber of the check valve to the crank chamber side.

  Moreover, it is preferable that the contact part of the valve body which contacts / separates with respect to a valve seat is made hemispherical. In this case, when the crank chamber pressure is higher than the intake manifold pressure, the valve port of the valve seat is more reliably closed by the hemispherical contact portion of the valve body. For this reason, in the low load operation state of the engine, the communication between the separation chamber and the check valve is more reliably blocked, and the oil is more reliably prevented from returning from the valve chamber of the check valve to the separation chamber. . In addition, since the abutting portion comes into contact with the valve seat in a line contact state in the valve-closed state, adhesion of the abutting portion to the valve seat is prevented. Therefore, when the intake manifold pressure becomes higher than the crank chamber pressure, the valve body is more reliably separated from the valve seat and is opened.

  Moreover, it is preferable to make a contact part hollow. In this case, since the mass of the valve body is reduced, the response of the check valve to the change in the differential pressure between the intake manifold pressure and the crank chamber pressure is improved. For this reason, when the intake manifold pressure becomes lower than the crank chamber pressure due to a change in the operating state of the engine, the valve body quickly contacts the valve seat, and the check valve quickly changes from the open state to the closed state. Switch. Therefore, oil can be more reliably recovered from blow-by gas when the engine operating state is switched.

  Moreover, it is preferable to provide the storage part which stores the oil discharged | emitted from the said separation part between a separation part and a non-return valve. In this case, when the check valve is closed, the oil separated in the separation unit is discharged from the separation unit to the storage unit and stored. Then, in the open state of the check valve, oil is introduced from the reservoir to the check valve. Accordingly, since oil does not easily accumulate in the separation part, the oil once separated from the blow-by gas is not easily taken out to the intake passage side by the blow-by gas sucked from the separation chamber to the intake passage side. Therefore, the oil separated from the blow-by gas can be returned more reliably to the engine side.

  In the cylinder head cover of the present invention, an oil mist separator is provided in a state in which the housing of the separating portion is integrated with the cylinder head cover formed of synthetic resin. Therefore, since the occupied space of the oil mist separator can be reduced, the mounting property on the vehicle is improved.

  Moreover, it is preferable that a separation part is provided with the conical separation chamber which turns the blowby gas introduce | transduced from the crank chamber, and the axis line is inclined with respect to the perpendicular direction. In this case, the volume of the portion where the oil mist separator protrudes outside from the main body of the cylinder head cover becomes smaller. Moreover, it is possible to prevent oil from being taken out from the separation chamber to the intake passage side so that the oil does not accumulate in the separation chamber. Therefore, the mounting property on the vehicle is improved and the oil is more reliably returned to the crank chamber side.

Next, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the cylinder head cover 12 provided in each cylinder 11 of the engine 10 is formed of nylon 66. One of the cylinder head covers 12 is provided with an oil mist separator 13 for recovering oil from blow-by gas.

  The oil mist separator 13 includes a housing 14 formed on the cylinder head cover 12, and a separation chamber 15 having a substantially conical shape and having an open conical bottom is formed therein. The separation chamber 15 has a lower end on the tip side, and an axis L thereof is inclined with respect to the vertical direction. The remainder angle of the inclination angle θ1 (0 <1 <90 °; inclination with respect to the vertical direction) of the axis L of the separation chamber 15 with respect to the vertical direction is larger than the inclination angle θ2 with respect to the axis L of the conical surface in the separation chamber 15. Is preferred. In this case, oil does not accumulate in the separation chamber 15.

  The conical bottom opening of the separation chamber 15 is closed by the end plate 16, and the guide cylinder 17 fitted in the central hole of the end plate 16 is disposed in the separation chamber 15. The inside of the guide cylinder 17 is a gas passage 18, and the gas passage 18 communicates with the outside of the housing 14. A disc-shaped partition wall 19 is integrally formed on the outer peripheral surface of the guide cylinder 17, and an annular gap is formed between the outer peripheral surface and the inner peripheral surface of the separation chamber 15. In this embodiment, the separation portion is constituted by the housing 14 forming the separation chamber 15 and the guide cylinder 17.

  The separation chamber 15 communicates with the internal space of the cylinder head cover 12 through a gas inlet 20 provided in the peripheral wall of the housing 14. The internal space of the cylinder head cover 12 communicates with the crank chamber via a blow-by gas passage (not shown) provided in the cylinder block of the engine 10. The gas inlet 20 is opened so as to be tangential to the inner peripheral surface of the separation chamber 15. Further, the separation chamber 15 can communicate with the inside of the cylinder head cover 12 through an oil discharge port 21 provided in the lower portion thereof.

  A connection member 23 that forms a gas flow path 22 communicating with the gas passage 18 is attached to a corresponding portion of the end plate 16 outside the housing 14. The connection member 23 is formed of nylon 66 and is welded to the housing 14. A well-known PCV valve 24 is attached to the gas flow path 22 in the connection member 23. The gas discharge port 24a of the PCV valve 24 is communicated with an intake manifold via a gas pipe (not shown).

  An oil case (reservoir) 26 formed of nylon 66 and having an oil chamber 25 is welded to a corresponding portion of the housing 14 inside the cylinder head cover 12. The oil chamber 25 stores the oil discharged from the oil discharge port 21. A check valve 27 is provided below the oil case 26 to allow the oil to be discharged from the oil chamber 25 and to stop the backflow of gas from the cylinder head cover 12 to the separation chamber 15 side.

  Next, the check valve 27 will be described in detail. As shown in FIGS. 2A, 2B, and 4, the check valve 27 includes a peripheral wall portion 29 having a substantially cylindrical valve chamber 28, and is attached to an end plate 30 fitted to the lower end opening thereof. Is formed with an oil outlet 31 for discharging oil from the valve chamber 28 to the inside of the cylinder head cover 12. The oil outlet 31 has an opening formed in a substantially asterisk shape (a star shape having six protrusions). Between the valve chamber 28 and the oil chamber 25 (shown in FIG. 4), there is a valve port 32 communicating with the valve chamber 28 and the oil chamber 25, and a conical surface positioned below the valve port 32. The valve seat 33 which consists of is formed. The valve chamber 28 accommodates a valve body 34 that can be opened and closed by opening and closing the valve seat 33 by being displaced in the vertical direction in the valve chamber 28.

  As shown in FIGS. 3A to 3C, the valve body 34 includes a substantially star-shaped substrate 36 having four projecting portions 35, and the upper surface thereof can contact and separate from the valve seat 33. A hemispherical contact portion 37 is integrally formed. In addition, the inside of the contact part 37 is hollow, and weight reduction of the valve body 34 is achieved. Further, leg portions (holding means) 38 protruding in the axial direction of the substrate 36 are integrally formed on the lower surface of the distal end portion of each protruding portion 35. Each leg portion 38 has a sharp shape, and the tip thereof can be brought into line contact with the upper surface (valve chamber wall) of the end plate 30. The valve body 34 and the oil outlet 31 are configured such that a part of the oil outlet 31 is opened as shown in FIG. 2A regardless of the displacement position of the valve body 34. This is achieved mainly by the fact that there are four projecting portions 35 of the valve body 34 and six projecting portions of the oil outlet 31.

Next, the operation of the oil mist separator 13 configured as described above will be described.
When the crank chamber pressure becomes higher than the intake manifold pressure in the no-load operation state of the engine 10, an upward biasing force due to the differential pressure is applied to the valve body 34 of the check valve 27. Then, the valve body 34 switches from the valve opening position shown in FIG. 4 to the valve closing position shown in FIG. 5, and the contact portion 37 of the valve body 34 contacts the valve seat 33 to close the valve port 32. At this time, blow-by gas containing oil mist in the crank chamber is introduced into the separation chamber 15 from the gas inlet 20 of the oil mist separator 13. The blow-by gas introduced into the separation chamber 15 from the gas introduction port 20 that opens in the tangential direction with respect to the inner circumferential surface of the separation chamber 15 is formed by the inner circumferential surface of the separation chamber 15 and the outer circumferential surface of the guide tube 17. It moves from the upper part of the separation chamber 15 to the lower part side while turning the substantially cylindrical space. At this time, the oil mist is centrifuged by the centrifugal force from the blow-by gas that moves while swirling, and the separated oil mist adheres to the inner peripheral surface of the separation chamber 15. The oil mist also adheres to the outer peripheral surfaces of the guide cylinder 17 and the partition wall 19. After the oil particles adhering to the inner peripheral surface of the separation chamber 15 and the outer peripheral surfaces of the guide cylinder 17 and the partition wall 19 grow and increase, the oil particles move downward along the inner peripheral surface of the separation chamber 15 by gravity. The oil is discharged from the oil discharge port 21 to the oil chamber 25. As described above, the oil is continuously separated from the blow-by gas, and the separated oil is accumulated in the oil chamber 25. On the other hand, the blow-by gas from which the oil mist is centrifuged moves to the downstream side of the separation chamber 15 through the passage between the inner peripheral surface of the separation chamber 15 and the outer peripheral surface of the partition wall 19, and then the tip of the guide cylinder 17 To the PCV valve 24 through the gas passage 18. The blow-by gas introduced into the PCV valve 24 is further drawn into the intake manifold.

  Further, when the engine 10 is changed from the no-load operation state to the low load operation state, the intake manifold pressure and the crank chamber pressure become substantially equal, the force applied to the valve body 34 of the check valve 27 is lost due to the differential pressure. Then, the valve body 34 switches from the valve closing position shown in FIG. 5 to the valve opening position shown in FIG. 4 due to its own weight, and the contact portion 37 moves away from the valve seat 33 to open the valve port 32. By the engagement between each leg portion 38 and the end plate 30, the leg plate 38 is held in a separated state with respect to the upper surface of the end plate 30. For this reason, the oil in the oil chamber 25 is discharged into the valve chamber 28 through the valve port 32. The oil discharged into the valve chamber 28 is discharged from the oil outlet 31 into the cylinder head cover 12 through an oil passage formed between the base plate 36 and the end plate 30 of the separated valve body 34. At this time, since a part of the oil outlet 31 is always open, the oil moved from the oil chamber 25 to the valve chamber 28 is smoothly returned into the cylinder head cover 12.

  Further, when the intake manifold pressure becomes higher than the crank chamber pressure in the high load operation state of the engine 10, a downward force due to the differential pressure is applied to the valve body 34 of the check valve 27. Then, the valve body 34 is pressed against the valve opening position shown in FIG. Even in this state, the oil in the valve chamber 28 is discharged into the cylinder head cover 12 through the oil passage between the valve body 34 and the end plate 30. For this reason, even in a high-load operation state of the engine 10, the oil in the oil chamber 25 is reliably returned to the cylinder head cover 12. Further, in this state, the valve body 34 comes into contact with the upper surface of the end plate 30 in a line contact state by the tip of each leg portion 38. For this reason, even if sludge adheres to the upper surface of the end plate 30 and the leg portions 38 of the valve body 34, the valve body 34 is difficult to adhere to the upper surface of the end plate 30. When the intake manifold pressure becomes higher than the crank chamber pressure, the valve body 34 is easily separated from the upper surface of the end plate 30 and is opened.

  As described above, according to this embodiment, in the opened state of the check valve 27 corresponding to the intake manifold pressure being higher than the crank chamber pressure, the valve body 34 separated from the valve seat 33 is The valve body 34 abuts against the upper surface of the end plate 30 in a line contact state, and is held in a separated state from the end plate 30. For this reason, even if sludge adheres to the inner wall of the valve chamber 28 or the valve body 34, the valve body 34 adheres to the upper surface of the end plate 30 in the valve open state in which oil is discharged from the separation chamber 15 to the crank chamber side. There is no. When the crank chamber pressure becomes higher than the intake manifold pressure, the valve body 34 is easily separated from the upper surface of the end plate 30 and comes into contact with the valve seat 33. As a result, since the communication between the separation chamber 15 and the check valve 27 is more reliably blocked, no gas is introduced from the crank chamber side to the separation chamber 15 side via the check valve 27. Therefore, oil is not returned from the valve chamber 28 of the check valve 27 to the separation chamber 15 side in the low load operation state of the engine 10. In addition, in the open state of the check valve 27, an oil passage that communicates the valve chamber 28 and the oil outlet 31 is formed between the valve body 34 and the upper surface of the end plate 30 of the valve chamber 28. Therefore, when the engine 10 is in a low load operation state, the oil is more reliably discharged from the check valve 27 to the crank chamber side. Therefore, the oil separated from the blow-by gas can be more reliably returned to the engine side.

  Further, each of the valve body 34 and the oil outlet 31 is formed in a star shape having three or more projecting portions in the displacement direction view of the valve body 34, and the number of projecting portions 35 of the valve body 34 and the projecting portions of the oil outlet 31. Different from the number of. Thereby, a part of the oil outlet 31 is always opened upward. As a result, the oil is discharged more smoothly from the valve chamber 28 of the check valve 27 toward the crank chamber side.

  Further, the contact portion 37 of the valve body 34 that contacts and separates from the valve seat 33 has a hemispherical shape, and the valve seat 33 has a conical surface. In this case, when the crank chamber pressure is higher than the intake manifold pressure, the hemispherical contact portion 37 of the valve body 34 contacts the conical valve seat 33, so that the valve port 32 of the valve seat 33 is Closed more securely. For this reason, when the engine 10 is in a no-load operation state, the communication between the separation chamber 15 and the check valve 27 is more reliably blocked, and the oil is returned from the valve chamber 28 of the check valve 27 to the separation chamber 15 side. More reliably prevented. In addition, since the contact portion 37 contacts the valve seat 33 in a line contact state in the valve-closed state, the contact portion 37 is prevented from closely contacting the valve seat 33. Therefore, when the intake manifold pressure becomes higher than the crank chamber pressure, the valve body 34 is more reliably separated from the valve seat 33 and is opened.

  Further, since the contact portion 37 is hollow, the mass of the valve body 34 is reduced, and the responsiveness of the check valve 27 to the change in the differential pressure between the intake manifold pressure and the crank pressure is improved. For this reason, when the intake manifold pressure becomes lower than the crank pressure due to a change in the operating state of the engine 10, the valve body 34 quickly comes into contact with the valve seat 33, and the check valve 27 changes from the open state to the closed state. Switch to quickly. Therefore, oil can be more reliably recovered from blow-by gas when the operating state of the engine 10 is switched.

  In addition, an oil chamber 25 for storing oil discharged from the separation chamber 15 is provided between the separation chamber 15 and the valve chamber 28. For this reason, when the check valve 27 is closed, the oil separated in the separation chamber 15 is discharged from the separation chamber 15 to the oil chamber 25 and stored. Then, oil is introduced from the oil chamber 25 into the valve chamber 28 of the check valve 27 in the open state of the check valve 27. Therefore, unlike the case where the check valve 27 is provided directly below the oil discharge port 21, oil does not easily accumulate in the separation chamber 15, so that the oil once separated from the blow-by gas is sucked from the separation chamber 15 to the intake manifold side. It is difficult to take out to the intake manifold side by blow-by gas. Therefore, the oil separated from the blowby gas can be returned to the engine 10 side more reliably.

  The cylinder head cover 12 is provided with an oil mist separator 13 in a state where the housing 14 of the separation chamber 15 is integrated. Therefore, since the occupied space of the oil mist separator 13 can be further reduced, the mounting property on the vehicle is improved.

  Further, the oil mist separator 13 is integrated with the cylinder head cover 12 so that the axis L of the conical separation chamber 15 is inclined with respect to the vertical direction. For this reason, the height which protrudes upwards from the main-body part of the cylinder head cover 12 becomes smaller. In addition, since oil does not accumulate in the separation chamber 15, no oil is taken out from the separation chamber 15 to the intake manifold side. Therefore, the mounting property on the vehicle is improved and the oil is more reliably returned to the crank chamber side.

In addition, this embodiment can also be changed and embodied as follows.
The oil chamber 25 is abolished, and a check valve 27 is provided immediately below the oil discharge port 21 of the separation chamber 15.

  -Change the number of protrusions of the valve body 34 and the oil outlet 31 so that the numbers are different from each other. For example, contrary to the above-described embodiment, the base plate 36 of the valve body 34 has a substantially asterisk shape, and the oil outlet 31 has a star shape having four protrusions.

  6 (a) and 6 (b), the lower surface of the base plate 36 of the valve body 34 in which the support piece 40 provided on the upper surface of the end plate 30 of the check valve 27 is not provided with the leg portion 38. It is set as the structure which hold | maintains the valve body 34 in the separation | spacing state with respect to the upper surface of the end plate 30 by making it contact | abut to a line contact state.

  As shown in FIG. 7, the housing 14 of the separation chamber 15 is integrated with the cylinder head cover 12 so that the axis L of the separation chamber 15 is horizontal. In this case, the oil discharge port 21 is provided in the lower part of the peripheral wall of the housing 14. Such a configuration is suitable for an in-line engine.

  As shown in FIG. 8, an oil mist separator 13 configured independently of the cylinder head cover 12 is mounted on the side surface of the cylinder head cover 12 so that the axis L of the separation chamber 15 is vertical. Such a configuration is suitable for an in-line engine.

  This invention is embodied in an oil mist separator that separates oil by rotating a plurality of impellers by the flow pressure of blow-by gas introduced into the separation chamber and attaching oil mist to the surface of each impeller. .

The longitudinal section showing the oil mist separator of one embodiment. (A) is a plane sectional view which shows a check valve, (b) is the sectional view on the aa line in (a). (A) is a front view which shows a valve body, (b) is a side view similarly, (c) is a bottom view similarly. The longitudinal cross-sectional view which shows the non-return valve of a valve closing state. The longitudinal cross-sectional view which shows the non-return valve of a valve opening state. (A) is the plane sectional view which shows the non-return valve in other embodiment, (b) is the bb sectional view taken on the line in (a). The longitudinal cross-sectional view which shows the oil mist separator in other embodiment. The longitudinal cross-sectional view which shows the oil mist separator in other embodiment. (A)-(c) is a longitudinal cross-sectional view which shows the conventional oil mist separator, all.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 12 ... Cylinder head cover, 13 ... Oil mist separator, 14 ... Housing which comprises a separation part, 15 ... Separation chamber, 17 ... Guide cylinder which comprises a separation part, 21 ... Oil discharge port, 25 ... Oil chamber, DESCRIPTION OF SYMBOLS 26 ... Oil case as a storage part, 27 ... Check valve, 28 ... Valve chamber, 31 ... Oil outlet, 33 ... Valve seat, 34 ... Valve body, 35 ... Projection part, 37 ... Contact part, 38 ... Holding means 40 as well as a support piece, L as an axis.

Claims (7)

An oil mist separator provided on a blow-by gas passage that communicates an engine crank chamber with an intake passage, a separation portion that separates oil from blow-by gas introduced from the crank chamber, and the separation portion toward the crank chamber And a check valve that restricts the inflow of gas from the crank chamber side to the separation portion side, and the check valve is displaced by a differential pressure between the intake side pressure and the crank chamber pressure. A valve body that regulates the flow of blow-by gas from the crank chamber side to the separation section side in a closed state in which the valve body abuts against a valve seat provided between the separation section and the valve body In the oil mist separator configured to discharge oil from the separation portion to the crank chamber side in the open state separated from the valve seat,
A holding means is provided between the valve body and the valve chamber wall in the valve open state to hold the valve body in a separated state with respect to the valve chamber wall ,
The valve body and the oil outlet of the valve chamber in which the valve body is accommodated are configured such that a part of the oil outlet is always open, and each of the valve body and the oil outlet has three or more protrusions. An oil mist separator characterized by having a star shape and having a different number of protrusions of the valve body and the number of protrusions of the oil outlet . The oil mist separator according to claim 1, wherein the holding means is a plurality of sharp legs. Oil mist separator according to claim 1 or claim 2 abutment toward and away from said valve body, characterized in that the semi-spherical shape with respect to the valve seat. The oil mist separator according to claim 3 , wherein the contact portion is hollow. Wherein between the separation unit and the check valve, as claimed in any one of claims 1 to 4, characterized in that it comprises a reservoir for reserving the by oil discharged from the separation unit Oil mist separator. A cylinder head cover, which is formed of a synthetic resin, includes the oil mist separator according to any one of claims 1 to 5 , and is formed integrally with a housing of the separation portion. The cylinder head cover according to claim 6 , wherein the separation unit includes a conical separation chamber that swirls blow-by gas introduced from the crank chamber, and an axis thereof is inclined with respect to a vertical direction.

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