Oil separator

Abstract

To provide technique capable of separating a larger amount of mist-like oil from blow-by gas containing the mist-like oil.SOLUTION: An oil separator 10, 100 includes a case 11 which is attached to an engine 40, and an oil trap 82 which is accommodated in the case and separates mist-like oil from gas generated in the engine and containing the mist-like oil. The oil trap includes a plurality of guides 82c, 83c arranged at a prescribed interval W2 and condensing the mist-like oil contained in the gas, and a distal end 82e of the guide comes into contact with a lower end surface 11c1 of the case or is arranged in a hole 11e formed on a lower end surface 11c of the case.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an oil separator.

Background Art

[0002] Patent Document 1 describes an oil separator disposed in a ventilation pipe that communicates from a crankcase to an intake pipe. This oil separator has a collision wall coated with a woven or non-woven fabric.

[0003] The blow-by gas containing mist-like oil collides with the woven or non-woven fabric, and the mist-like oil is adsorbed by the woven or non-woven fabric. Thereby, the mist-like oil is separated from the blow-by gas containing the mist-like oil.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for example, when the flow rate of the blow-by gas containing mist-like oil increases due to an increase in the size of the engine or the like, there is a possibility that the mist-like oil cannot be sufficiently separated by the woven or non-woven fabric.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a technique for separating more mist-like oil from the blow-by gas containing mist-like oil.

Means for Solving the Problems

[0007] To achieve the above object, the oil separator according to the present invention includes a case attached to an engine, and an oil trap accommodated in the case for separating mist-like oil from gas containing the mist-like oil generated by the engine. The oil trap has a plurality of guide portions arranged at a predetermined interval for aggregating the mist-like oil contained in the gas, and the tip of the guide portion contacts the lower end surface of the case or is disposed in a hole formed in the lower end surface of the case.

Effect of the Invention

[0008] According to the present invention, more mist-like oil can be separated from the blow-by gas containing mist-like oil.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7

Figure 8A

Figure 8B

Figure 9

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and duplicate explanations will be omitted as appropriate. In this specification, "down" refers to the mounting direction of the oil separator 10 with respect to the engine 40, and "up" refers to the opposite direction. Also, the circumferential direction is defined around the vertical direction, and the direction perpendicular to the vertical direction is the radial direction.

[0011] FIG. 1 is a view showing a ventilation system 1 and an engine system 1a according to an embodiment. FIG. 2A is a perspective view of an oil separator 10 according to an embodiment. FIG. 2B is a plan view of an oil separator 10 according to an embodiment. FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2B. FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2B. FIG. 5A is a perspective view of a lower case 11a of the oil separator 10 of FIG. 2. FIG. 5B is a plan view of a lower case 11a of the oil separator 10 of FIG. 2. FIG. 6A is a perspective view of an oil trap 82 of the oil separator 10 of FIG. 2. FIG. 6B is a side view of an oil trap 82 of the oil separator 10 of FIG. 2. FIG. 7 is a partially enlarged view showing an enlarged portion A of FIG. 4. FIG. 8A is a view showing the flow of blow-by gases B1, B2 and oil droplets L in the cross-sectional view taken along line A-A of FIG. 2B. FIG. 8B is a view showing the flow of blow-by gases B1, B2 and oil droplets L in the cross-sectional view taken along line B-B of FIG. 2B. In FIGS. 3, 4, 8A, and 8B, the state where the oil separator 10 is attached to the head cover 41 is shown.

[0012] [Engine System] As shown in FIG. 1, the engine system 1a includes an intake pipe 30, an engine 40, an air filter 50, a turbo 60, and an air cooler 70. Note that the engine system 1a may not include the turbo 60 and the air cooler 70.

[0013] The intake pipe 30 is a component that supplies the outside air filtered by the air filter 50 to the combustion chamber of the engine 40. In the present embodiment, a turbo 60 and an air cooler 70 are arranged in the intake pipe 30. The turbo 60 is a component that drives a turbine using the exhaust flow and compresses the outside air in the intake pipe 30. Thereby, the turbo 60 increases the amount of air supplied to the combustion chamber (increases the air density). The air cooler 70 is a component that cools the high-temperature air compressed by the turbo 60 and increases the density of the air supplied to the combustion chamber.

[0014] The engine 40 has a head cover 41, an engine body 42, and an oil pan 43.

[0015] In the present embodiment, the engine body 42 includes a cylinder block and a cylinder head. The cylinder block has cylinders inside. Pistons are accommodated in the cylinders. In the cylinder block, a crankshaft is accommodated in the lower space below the piston (hereinafter referred to as the lower space of the cylinder block). By burning the air-fuel mixture in the combustion chamber in the cylinder, the piston reciprocates. The cylinder head is attached to the upper surface of the cylinder block. The cylinder head houses a valve operating mechanism and the like that supply the air-fuel mixture to the combustion chamber and discharge the combustion gas from the combustion chamber.

[0016] The head cover 41 is a component that covers the upper part of the cylinder head. The head cover 41 according to the present embodiment has a substantially rectangular parallelepiped shape and is open downward. The head cover 41 has a lower opening 41a, mounting holes 41b, an upper opening 41c, and an inner space 41d of the cover (see FIG. 3 and the like).

[0017] The lower opening 41a is a part for attaching the head cover 41 to the upper part of the cylinder head. The lower opening 41a faces the upper part of the cylinder head vertically.

[0018] The mounting hole 41b is provided in the upper surface of the head cover 41 and in the vicinity of the upper opening 41c. The mounting hole 41b penetrates the head cover 41 in the vertical direction. A bolt for fixing the oil separator 10 to the head cover 41 is inserted into the mounting hole 41b. The number of bolts and mounting holes 41b is not particularly limited as long as the oil separator 10 can be fixed to the head cover 41.

[0019] The upper opening 41c is a hole in which the oil separator 10 is mounted. The upper opening 41c is provided in the upper surface of the head cover 41. The upper opening 41c penetrates the head cover 41 in the vertical direction. The number of upper openings 41c is the same as the number of oil separators 10 to be mounted on the head cover 41. In the present embodiment, one example is shown.

[0020] The cover inner space 41d is the inner space of the head cover 41 located above the lower opening 41a. The cover inner space 41d communicates with the upper part of the cylinder head, that is, is spatially connected.

[0021] The oil pan 43 is attached to the lower surface of the cylinder block and stores engine oil used for lubricating the piston and the like. The inner space of the oil pan 43 communicates with the lower space of the cylinder block.

[0022] In the present embodiment, the combustion gas and unburned gas generated in the combustion chamber and blown through the gap between the piston and the cylinder into the lower space of the cylinder block are called blow-by gas. In this blow-by gas, mist-like oil is adsorbed in the lower space of the cylinder block. The blow-by gas B1 (an example of a gas containing mist-like oil) containing mist-like oil flows into the cover inner space 41d through the cylinder block and the cylinder head.

[0023] [Ventilation System] As shown in FIG. 1, the ventilation system 1 includes an oil separator 10 and a breather pipe 20. The ventilation system 1 is attached to the engine system 1a.

[0024] <Breather Pipe> The breather pipe 20 is a component for returning the blow-by gas B2, from which mist-like oil has been separated and which is discharged from the oil separator 10, to the intake pipe 30. One end of the breather pipe 20 is attached to a gas discharge port 3j described later, and the other end is attached to the intake pipe 30.

[0025] <Oil separator> The oil separator 10 separates mist-like oil from the blow-by gas B1. The oil separator 10 includes a case 11, an oil trap 82, a collection structure 12, an oil seal 16, a leaf spring 80, and a check valve 84 (see FIG. 3 etc.).

[0026] <<Case>> The case 11 is a component that constitutes the exterior of the oil separator 10. The case 11 has an internal space in which the oil trap 82, the collection structure 12, the leaf spring 80, the check valve 84, etc. are arranged.

[0027] The case 11 has a lower case 11a and an upper case 11b.

[0028] The lower case 11a is a frustum-shaped cylindrical component with an open upper end. Through the opening, the oil trap 82, the collection structure 12, the leaf spring 80, the check valve 84, etc. are accommodated in the internal space of the lower case 11a.

[0029] The lower end surface 11c of the lower case 11a is formed in a funnel shape. Specifically, the lower end surface 11c is inclined downward toward the center in the radial direction of the lower case 11a. The lower end surface 11c has a surface 11d facing the inside of the lower case 11a. The surface 11d is formed flat.

[0030] The lower end surface 11c has a hole 11e that is recessed downward. In this example, the hole 11e has a rectangular bottom wall surface 11e2 and four side wall surfaces 11e1 that stand upright upward from the four sides of the bottom wall surface 11e2. The internal space of the hole 11e is partitioned by the bottom wall surface 11e2 and the side wall surfaces 11e1. The upper edge of the side wall surface 11e1 is connected to the edge of the surface 11d. In this example, a plurality of holes 11e are arranged at predetermined intervals along the circumferential direction. Note that the shape of the hole 11e is not particularly limited as long as the tip 82e of the guide portion 82c can be arranged therein.

[0031] Further, the lower case 11a has a protrusion 2a, an inflow hole 2b, an oil discharge port 2c, a claw portion 2d, a mounting portion 2e, a stopper portion 2f, and a groove 2g.

[0032] The protrusion 2a is a portion that holds the oil trap 82 from below. The protrusion 2a protrudes from the inner surface of the lower case 11a toward the radial center of the lower case 11a. The number of the protrusions 2a is not particularly limited as long as the oil trap 82 can be held from below.

[0033] The inflow hole 2b is a portion for allowing the blow-by gas B1 to flow from the cover inner space 41d into the interior of the oil separator 10, that is, the internal space of the lower case 11a. The inflow hole 2b according to the present embodiment is an opening provided on the side surface of the lower case 11a. The inflow hole 2b communicates the internal space of the lower case 11a with the external space (that is, the cover inner space 41d). The inflow hole 2b is provided so as not to be radially opposed to the protrusion 2a when viewed from above. In the example of FIG. 5B, the inflow hole 2b is provided between adjacent protrusions 2a in the circumferential direction. The position and number of the inflow holes 2b are not particularly limited as long as the blow-by gas B1 can be made to flow into the interior of the oil separator 10.

[0034] The oil discharge port 2c is a part for allowing the oil droplet-shaped oil L to flow out to the outside of the oil separator 10. The oil discharge port 2c is an opening provided at the center of the lower end surface 11c of the lower case 11a. The oil discharge port 2c communicates the internal space of the lower case 11a with the external space. Specifically, in a state where the oil separator 10 is attached to the head cover 41, the oil discharge port 2c communicates the internal space of the lower case 11a with the inner space 41d of the cover.

[0035] The claw portion 2d is a part that fits with a hook portion 3b described later to attach the upper case 11b to the lower case 11a. The claw portion 2d is provided so as to protrude radially outward on the outer peripheral surface near the upper end of the lower case 11a. The position and number of the claw portions 2d are not particularly limited as long as the upper case 11b can be attached to the lower case 11a.

[0036] The attachment portion 2e is a part for attaching the oil separator 10 to the head cover 41. The attachment portion 2e extends radially outward from the outer side surface of the lower case 11a. In the present embodiment, two attachment portions 2e are provided at opposing positions on the outer side surface of the lower case 11a.

[0037] The attachment portion 2e has an attachment hole 2e1 that penetrates the attachment portion 2e in the vertical direction. The attachment hole 2e1 is a part for attaching the oil separator 10 to the head cover 41 by inserting a bolt. The attachment hole 2e1 is arranged directly above the attachment hole 41b of the head cover 41 when the oil separator 10 is attached to the head cover 41 (Fig. 4). The number of the attachment holes 2e1 is the same as the number of the attachment holes 41b of the head cover 41. In the present embodiment, an example where the number of the attachment holes 2e1 is two is shown.

[0038] The stopper portion 2f is a part that determines the vertical position of the lower case 11a with respect to the upper opening 41c of the head cover 41. The stopper portion 2f is formed in an annular and plate shape. The stopper portion 2f is provided on the outer side surface of the lower case 11a. The outer diameter of the stopper portion 2f is larger than the diameter of the upper opening 41c. The position of the lower surface of the stopper portion 2f is equal to the position of the lower surface of the mounting portion 2e. That is, the lower surface of the stopper portion 2f is flush with the lower surface of the mounting portion 2e. The stopper portion 2f is provided above the inflow hole 2b.

[0039] The groove 2g is a part where the oil seal 16 to be described later is arranged. The groove 2g is provided in the circumferential direction on the outer side surface of the lower case 11a. In the example of FIG. 3, the groove 2g is provided in the vicinity below the stopper portion 2f.

[0040] The lower case 11a is attached to the upper opening 41c of the head cover 41 so as to be embedded from above. At this time, the lower case 11a is attached to the upper opening 41c so that the axes of the mounting hole 41b of the head cover 41 and the mounting hole 2e1 of the lower case 11a coincide. Then, the lower surface of the stopper portion 2f contacts the edge of the upper opening 41c, and the vertical position of the lower case 11a is determined. Then, a bolt is inserted into the mounting hole 41b of the head cover 41 and the mounting hole 2e1 of the lower case 11a, and the bolt is tightened with a nut, so that the lower case 11a is fixed to the head cover 41.

[0041] In a state where the lower case 11a is fixed to the head cover 41, the portion below the stopper portion 2f of the lower case 11a is located below the upper surface of the head cover 41. Also, the portion below the groove 2g, that is, the inflow hole 2b and the oil discharge port 2c, are arranged in the cover inner space 41d. Therefore, the internal space of the lower case 11a communicates with the cover inner space 41d through the inflow hole 2b and the oil discharge port 2c.

[0042] The upper case 11b is a component provided to close the opening located at the upper end of the lower case 11a. The upper case 11b has an outer cylinder 3a, a hook portion 3b, a stopper portion 3c, a large-diameter cylinder 3d, a small-diameter cylinder 3e, a lid portion 3f, an opening portion 3g, a first connection portion 3h, a second connection portion 3i, a gas discharge port 3j, and a PCV valve 3k.

[0043] The outer cylinder 3a is a part that closes the opening located at the upper end of the lower case 11a. The outer cylinder 3a has a substantially cylindrical shape with a closed upper end and an open lower end. The upper case 11b is attached to the lower case 11a such that the opening at the lower end of the outer cylinder 3a faces the opening at the upper end of the lower case 11a.

[0044] The hook portion 3b is a part that engages with the claw portion 2d of the lower case 11a to attach the upper case 11b to the lower case 11a. The hook portion 3b extends radially outward from the outer side surface of the outer cylinder 3a and forms an annular shape that extends downward from the radially outer end. The position and number of the hook portions 3b are not particularly limited as long as the upper case 11b can be attached to the lower case 11a.

[0045] The stopper portion 3c is a part that restricts the movement of the oil seal 88. The stopper portion 3c is an annular portion that protrudes radially outward from the outer side surface of the outer cylinder 3a. The oil seal 88 is disposed on the lower surface of the stopper portion 3c to seal between the lower case 11a and the upper case 11b.

[0046] The large-diameter cylinder 3d is a part that partitions the inside of the upper case 11b. The large-diameter cylinder 3d has a cylindrical shape with a smaller diameter than the outer cylinder 3a. The large-diameter cylinder 3d is disposed radially inside the outer cylinder 3a.

[0047] The small-diameter cylinder 3e is a part that, together with the large-diameter cylinder 3d, partitions the inside of the upper case 11b. The small-diameter cylinder 3e has a cylindrical shape with a smaller diameter than the large-diameter cylinder 3d. The small-diameter cylinder 3e is disposed radially inside the large-diameter cylinder 3d.

[0048] The lid portion 3f closes the opening below the small-diameter cylindrical body 3e and is a part that restricts the movement of the spring 3k2 described later. The lid portion 3f is provided at the lower end of the small-diameter cylindrical body 3e. The lid portion 3f partitions the space inside the upper case 11b together with the small-diameter cylindrical body 3e. Further, the lid portion 3f has a cylindrical shape with a smaller diameter than the small-diameter cylindrical body 3e and has a protrusion 3f1 that protrudes upward. This protrusion 3f1 is inserted into the inner space of the spring 3k2 from below and restricts the radial movement of the spring 3k2.

[0049] The opening 3g is a part for allowing the blow-by gas B2 to flow into the inside of the small-diameter cylindrical body 3e. The opening 3g is the opening at the upper end of the small-diameter cylindrical body 3e.

[0050] The first connection portion 3h is a part that connects the large-diameter cylindrical body 3d and the outer cylinder 3a and prevents the blow-by gas B2 from passing through. The first connection portion 3h is an annular member. In the present embodiment, the first connection portion 3h is provided from the upper end of the large-diameter cylindrical body 3d toward the inner peripheral surface of the outer cylinder 3a.

[0051] The second connection portion 3i is a part that connects the small-diameter cylindrical body 3e and the large-diameter cylindrical body 3d. The second connection portion 3i is, for example, a square member. The position and number of the second connection portions 3i are not particularly limited as long as the small-diameter cylindrical body 3e and the large-diameter cylindrical body 3d can be connected. In the present embodiment, the second connection portion 3i is provided from the inner peripheral surface of the large-diameter cylindrical body 3d toward the outer peripheral surface of the small-diameter cylindrical body 3e, and a plurality (for example, three) are provided at intervals in the circumferential direction. That is, the gap between the second connection portions 3i allows the blow-by gas B2 to pass through.

[0052] The gas discharge port 3j is a part for allowing the blow-by gas B2 to flow out from the inside of the oil separator 10 to the outside. The gas discharge port 3j according to the present embodiment has a cylindrical shape. One gas discharge port 3j is provided so as to penetrate the side surface of the large-diameter cylindrical body 3d and the side surface of the outer cylinder 3a radially outward from the side surface of the small-diameter cylindrical body 3e and extend to the outside of the outer cylinder 3a. The internal space of the gas discharge port 3j communicates with the internal space of the small-diameter cylindrical body 3e. A breather pipe 20 is connected to the gas discharge port 3j.

[0053] The PCV valve 3k is a member for opening and closing the opening 3g of the small-diameter cylinder body 3e. The PCV valve 3k includes a diaphragm valve 3k1 and a spring 3k2.

[0054] The diaphragm valve 3k1 opens and closes the opening 3g. The diaphragm valve 3k1 has a disk shape. The diaphragm valve 3k1 is housed in the internal space of the upper case 11b so as to face the opening 3g.

[0055] The diaphragm valve 3k1 has a valve portion 3kv and a membrane portion 3km. The valve portion 3kv is a part that opens and closes the opening 3g. In the present embodiment, the shape of the valve portion 3kv is disk-shaped. The valve portion 3kv is provided above the opening 3g. The membrane portion 3km is a part that connects the valve portion 3kv and the outer cylinder 3a. Specifically, the membrane portion 3km connects the radially outer end of the valve portion 3kv and the inner peripheral surface of the outer cylinder 3a. The membrane portion 3km is an annular part that elastically deforms.

[0056] The spring 3k2 supports the valve portion 3kv in a state where it can move up and down. The spring 3k2 is a coil spring. The spring 3k2 is sandwiched between the valve portion 3kv and the lid portion 3f inside the small-diameter cylinder body 3e and below the valve portion 3kv, and biases the valve portion 3kv upward.

[0057] The internal space of the upper case 11b is partitioned by the small-diameter cylinder body 3e and the lid portion 3f. In the present embodiment, the space partitioned by the outer surface of the small-diameter cylinder body 3e, the lower surface of the lid portion 3f, and the inner surface of the outer cylinder 3a is described as the upper upstream space S4. Also, the space partitioned by the inner surface of the small-diameter cylinder body 3e and the upper surface of the lid portion 3f is described as the upper downstream space S5.

[0058] When the spring 3k2 contracts, the membrane portion 3km elastically deforms and extends, and only the valve portion 3kv moves downward, and the valve portion 3kv and the upper end of the small-diameter cylinder 3e come into contact. As a result, the opening 3g is closed, and the upper upstream space S4 and the upper downstream space S5 are blocked from each other. On the other hand, when the spring 3k2 extends, the membrane portion 3km elastically deforms and contracts, the valve portion 3kv moves upward, and the valve portion 3kv and the upper end of the small-diameter cylinder 3e separate. As a result, the opening 3g opens, and the upper upstream space S4 and the upper downstream space S5 communicate with each other.

[0059] <<Oil trap>> The oil trap 82 separates mist-like oil from the blow-by gas B1 generated in the engine 40. As shown in FIG. 6A, the oil trap 82 according to the present embodiment is an annular member. The oil trap 82 has an annular surface portion 82a, an inclined surface portion 82b, and a plurality of guide portions 82c.

[0060] The annular surface portion 82a is a plate-like portion having a predetermined width in the radial direction. The inclined surface portion 82b is a plate-like portion having a tapered shape that tapers downward. The inclined surface portion 82b is provided at the inner peripheral edge of the annular surface portion 82a. Note that the inclined surface portion 82b may extend vertically downward or substantially vertically downward from the inner peripheral edge of the annular surface portion 82a.

[0061] The guide portion 82c prevents the mist-like oil from scattering by aggregating the mist-like oil contained in the collided blow-by gas B1. Further, the guide portion 82c guides the aggregated mist-like oil (that is, oil droplet-like oil L) to the surface 11d of the lower end surface 11c. The guide portion 82c is a plate-like portion that extends vertically downward or substantially vertically downward from the lower edge of the inclined surface portion 82b. Note that the guide portion 82c may be formed in a tapered shape that tapers downward from the lower edge of the inclined surface portion 82b, or may be formed in an inverted tapered shape that widens downward from the lower edge of the inclined surface portion 82b.

[0062] A plurality of guide portions 82c are provided. The number of the guide portions 82c is set to be equal to or greater than the number of the inflow holes 2b. The number of the guide portions 82c is not particularly limited as long as it is equal to or greater than the number of the inflow holes 2b. A notch 82d is formed between the guide portions 82c. The notch 82d has a predetermined interval W2. The predetermined interval W2 is the width in the circumferential direction of the notch 82d. In the example of FIG. 6, the width W1 of the guide portion 82c is smaller than the width of the notch 82d, that is, the predetermined interval W2. Preferably, the width W1 of the guide portion 82c is equal to the width of the notch 82d, that is, the predetermined interval W2.

[0063] The oil trap 82 is housed in the lower case 11a (see FIGS. 3, 7, etc.). The annular surface portion 82a of the oil trap 82 is placed on the protrusion 2a provided on the lower case 11a. The oil trap 82 is positioned with respect to the case 11 when the annular surface portion 82a is placed on the protrusion 2a. In a state where the oil trap 82 is positioned with respect to the case 11, at least one of the guide portions 82c is at least partially opposed to the inflow hole 2b. Specifically, the guide portion 82c is opposed to the inflow hole 2b in the radial direction. Further, in a state where the oil trap 82 is positioned with respect to the case 11, the tip 82e of the guide portion 82c is disposed in the hole 11e of the lower case 11a. Specifically, the tip 82e of the guide portion 82c is disposed with a gap between it and the hole 11e (that is, with a gap between the side wall surface 11e1 and the bottom wall surface 11e2). Preferably, the distance between the tip 82e of the guide portion 82c and the bottom wall surface 11e2 is 2 mm or less. In this case, the mist-like oil (that is, oil droplet-like oil) aggregated by the guide portion 82c easily flows along the guide portion 82c to the bottom wall surface 11e2.

[0064] <<Collection Structure>> The collection structure 12 is a structure that is housed in the lower case 11a and separates mist-like oil from the blow-by gas B1 generated by the engine 40. As shown in FIGS. 3 and 4, the collection structure 12 includes a main body portion 12a, a regulating valve 12b, a collection body 12c, and a pressing member 12e (see FIGS. 3 and 4).

[0065] As shown in FIG. 4, the main body portion 12a is a portion that constitutes a cylindrical frame which is the basic part of the collection structure 12. The main body portion 12a has an annular disk portion 12a1, a small-diameter cylindrical portion 12a2, a large-diameter cylindrical portion 12a3, a flange portion 12a4, a wall plate portion 12a5, and a support portion 12a6.

[0066] The annular disk portion 12a1 is a portion that connects the small-diameter cylindrical portion 12a2 and the large-diameter cylindrical portion 12a3. The annular disk portion 12a1 is annular and plate-shaped with a through-hole formed in the central portion. The outer edge portion of the annular disk portion 12a1 is spaced apart from the inner surface of the lower case 11a, thereby forming a predetermined gap 13c.

[0067] The small-diameter cylindrical portion 12a2 is a portion that constitutes the upper inner side of the main body portion 12a. The small-diameter cylindrical portion 12a2 is cylindrical. The small-diameter cylindrical portion 12a2 protrudes upward along the radially inner edge of the annular disk portion 12a1. The ends of the small-diameter cylindrical portion 12a2 are open both at the top and bottom.

[0068] The large-diameter cylindrical portion 12a3 is a portion that constitutes the central portion of the main body portion 12a. The large-diameter cylindrical portion 12a3 is cylindrical. The diameter of the large-diameter cylindrical portion 12a3 is larger than the diameter of the small-diameter cylindrical portion 12a2. The large-diameter cylindrical portion 12a3 protrudes downward from the lower surface of the annular disk portion 12a1.

[0069] The flange portion 12a4 is a portion that constitutes the lower outer side of the main body portion 12a. The flange portion 12a4 is annular. The outer diameter of the flange portion 12a4 is slightly smaller than the inner diameter of the lower case 11a. The flange portion 12a4 is provided at the lower end of the large-diameter cylindrical portion 12a3. Further, a groove that opens radially outward is formed in the circumferential direction in the flange portion 12a4. An oil seal 90 is disposed in the groove to seal between the flange portion 12a4 and the lower case 11a.

[0070] The wall plate part 12a5 is a part that constitutes the lower center of the main body part 12a. The wall plate part 12a5 is provided on the flange part 12a4. The wall plate part 12a5 is disposed inside the flange part 12a4 and forms a plate shape extending in the radial direction. A hole penetrating in the vertical direction is formed at the radial center of the wall plate part 12a5. A check valve 84 is disposed in the hole.

[0071] The support part 12a6 is a part that constitutes the upper outer side of the main body part 12a. The diameter of the support part 12a6 is larger than the diameter of the small-diameter cylinder part 12a2. The support part 12a6 is provided, for example, four in number at predetermined intervals in the circumferential direction on the upper surface of the annular disk part 12a1 on the radially outer side of the small-diameter cylinder part 12a2. The support part 12a6 extends upward from the upper surface of the annular disk part 12a1.

[0072] When the main body part 12a is fitted into the lower case 11a from above, the main body part 12a partitions the internal space of the lower case 11a into a space on the side of the inflow hole 2b (referred to as the lower upstream space S1) and a space on the opening side located at the upper end of the lower case 11a (referred to as the second lower downstream space S3). The lower upstream space S1 is the space on the side of the inflow hole 2b including the internal space of the main body part 12a among the internal space of the lower case 11a partitioned by the main body part 12a. The second lower downstream space S3 is the space between the collection structure 12 and the lower case 11a in the space on the opening side among the internal space of the lower case 11a partitioned by the main body part 12a.

[0073] The regulating valve 12b is a component that regulates the flow rate of the blow-by gas B1 flowing in from the lower upstream space S1. The regulating valve 12b has a valve body 12b1, a valve elastic body 12b2, a cylindrical part 12b3, and a spring 12b4 (see FIGS. 3 and 4).

[0074] The valve body 12b1 is a valve element that opens and closes the upper end opening of the small-diameter cylindrical portion 12a2. The valve body 12b1 has a disc shape. The valve body 12b1 is disposed above the upper end opening of the small-diameter cylindrical portion 12a2. When the valve body 12b1 moves up and down, the upper end opening of the small-diameter cylindrical portion 12a2 opens and closes. Also, when the upper surface of the valve body 12b1 contacts the lower surface of the cylindrical portion 12e1 of the pressing member 12e described later, the upward movement of the valve body 12b1 is restricted.

[0075] The valve elastic body 12b2 alleviates the impact when the valve body 12b1 approaches the upper end opening of the small-diameter cylindrical portion 12a2. The valve elastic body 12b2 is an annular member having elasticity. The valve elastic body 12b2 is provided along the outer peripheral edge of the lower surface of the valve body 12b1. When the valve body 12b1 moves downward, the valve elastic body 12b2 contacts the upper end opening of the small-diameter cylindrical portion 12a2. When the valve body 12b1 moves upward, the valve elastic body 12b2 moves away upward from the upper end opening of the small-diameter cylindrical portion 12a2, and an annular gap is formed between the valve elastic body 12b2 and the upper end of the small-diameter cylindrical portion 12a2. This gap serves as the flow path C1 for the blow-by gas B1 that has flowed into the lower upstream space S1. The size of the flow path C1 for this blow-by gas B1 changes depending on the vertical position of the valve body 12b1. That is, the flow path C1 is a flow path with a changing opening degree. The inlet of the flow path C1 is the internal space (lower upstream space S1) of the small-diameter cylindrical portion 12a2. The outlet of the flow path C1 is outside the small-diameter cylindrical portion 12a2 and outside the valve body 12b1.

[0076] The cylindrical portion 12b3 is a part that lowers the center of gravity position of the control valve 12b and makes it difficult for the control valve 12b to tilt with respect to the main body portion 12a when a non-uniform force acts on the control valve 12b. The cylindrical portion 12b3 is a cylindrical part. The cylindrical portion 12b3 is provided so as to protrude downward from the lower surface of the valve body 12b1. In the present embodiment, the cylindrical portion 12b3 is located within the lower upstream space S1.

[0077] Spring 12b4 supports the valve body 12b1 in a vertically movable state. Spring 12b4 is a coil spring. Spring 12b4 is disposed on the upper surface of the valve body 12b1. Specifically, spring 12b4 is sandwiched between the upper surface of the valve body 12b1 and the lower surface of the disk portion 12e2 of the pressing member 12e described later, and biases the valve body 12b1 downward.

[0078] The collector 12c is a component that has air permeability and collects mist-like oil from the blow-by gas B1. The collector 12c is, for example, a non-woven fabric. The collector 12c faces the outlet of the flow path C1 in the radial direction. Among the internal spaces of the lower case 11a partitioned by the main body portion 12a, the space between the collector 12c and the outside of the regulating valve 12b and the outside of the small-diameter cylinder portion 12a2 in the opening-side space located at the upper end of the lower case 11a is defined as the first lower downstream space S2.

[0079] The collector 12c is held by being sandwiched between the support portion 12a6 from the outer side in the radial direction and the small-diameter cylinder portion 12a2 from the inner side in the radial direction. By being held by the support portion 12a6 and the small-diameter cylinder portion 12a2, the collector 12c is arranged in an annular shape so as to surround the regulating valve 12b with a radial gap on the outer peripheral side. Note that the collector 12c may be held from either the outer side or the inner side in the radial direction.

[0080] The pressing member 12e is a member that presses the spring 12b4 from above. The pressing member 12e has a cylindrical portion 12e1, a disk portion 12e2, and a columnar surface portion 12e3.

[0081] The disk portion 12e2 is a part that presses the spring 12b4 from above. The lower surface of the disk portion 12e2 presses the spring 12b4 from above.

[0082] The cylindrical portion 12e1 is a part that restricts the radial movement of the spring 12b4. The cylindrical portion 12e1 is a cylindrical part with an open lower end. The cylindrical portion 12e1 is provided on the lower surface of the disk portion 12e2. The spring 12b4 is disposed on the outer periphery of the cylindrical portion 12e1. Thus, the radial movement of the spring 12b4 is restricted. Also, when the adjustment valve 12b moves upward, the upper surface of the valve body 12b1 contacts the lower end of the cylindrical portion 12e1. Thereby, the upward movement of the adjustment valve 12b is restricted.

[0083] The columnar surface portion 12e3 is a part that extends downward along the outer edge of the disk portion 12e2 to the height of the upper surface of the trapping body 12c and then extends radially outward from the lower end. The columnar surface portions 12e3 are provided at intervals in the circumferential direction on the outer edge portion of the disk portion 12e2. The columnar surface portion 12e3 may contact the upper surface of the trapping body 12c on the lower surface of the portion extending radially outward and support the trapping body 12c from above.

[0084] The storage chamber 13 is partitioned by the trapping structure 12 and the case 11. The storage chamber 13 is a space for storing the oil droplet-shaped oil L formed by the aggregation of mist-like oil. The storage chamber 13 has a main space 13a and a discharge flow path 13b.

[0085] As shown in FIG. 4, the main space 13a is a space whose outer side in the radial direction is partitioned by the lower case 11a, whose inner side in the radial direction is partitioned by the large-diameter cylindrical portion 12a3, and whose lower side is partitioned by the flange portion 12a4. The main space 13a is formed in an annular shape. The main space 13a has a gap 13c on the upper side. The gap 13c communicates with the second lower downstream space S3.

[0086] As shown in FIG. 3, the discharge flow path 13b is a space that extends radially inward and downward from at least one location on the inner side in the radial direction of the main space 13a. In this embodiment, a case where there are two discharge flow paths 13b is shown. The inner and lower end of the discharge flow path 13b opens downward. Thereby, the oil droplet-shaped oil L in the storage chamber 13 is discharged into the internal space of the engine 40 (i.e., the cover inner space 41d) through the oil discharge port 2c.

[0087] <<Oil seal>> The oil seal 16 is attached to the lower case 11a. Specifically, the oil seal 16 is disposed in a groove 2g provided in the lower case 11a. With the oil seal 16 disposed in the groove 2g, the lower case 11a is fitted into the head cover 41, whereby the oil seal 16 is sandwiched between the head cover 41 and the lower case 11a to seal between the two.

[0088] <<Check valve>> The check valve 84 is a part for discharging the oil droplet-shaped oil L from the storage chamber 13 to the space 41d inside the cover. The check valve 84 is provided at the opening at the radially inner and lower end of the discharge passage 13b. The check valve 84 is a valve for opening and closing the opening at the radially inner and lower end of the discharge passage 13b. The check valve 84 has a valve body 84a, a shaft portion 84b, and a stopper portion 84c.

[0089] The valve body 84a is a part for opening and closing the opening at the radially inner and lower end of the discharge passage 13b. The valve body 84a is a circular plate member. The position and number of the valve body 84a are not particularly limited as long as the opening at the radially inner and lower end of the discharge passage 13b can be opened and closed. In the present embodiment, one valve body 84a is provided so as to cover the opening at the radially inner and lower end of the discharge passage 13b.

[0090] The shaft portion 84b is a part for restricting the moving direction of the valve body 84a. The shaft portion 84b is a rod-shaped part. The shaft portion 84b is provided so as to penetrate the center of the valve body 84a. The shaft portion 84b is inserted into a hole formed at the radial center of the wall plate portion 12a5 constituting the discharge passage 13b. Thereby, the shaft portion 84b can move up and down along the through hole together with the valve body 84a. When the shaft portion 84b moves up and down, the valve body 84a also moves up and down to open and close the opening at the radially inner and lower end of the discharge passage 13b.

[0091] The stopper portion 84c is a part that regulates the amount of vertical movement of the valve body 84a and the shaft portion 84b. The stopper portion 84c is a part where a part of the shaft portion 84b bulges in the radial direction. The stopper portion 84c is provided at a portion of the shaft portion 84b that is separated upward by a predetermined distance from the upper surface of the valve body 84a. Here, the predetermined distance is the length obtained by adding the vertical length of the hole and the amount of vertical movement of the valve body 84a. The diameter of the stopper portion 84c is larger than the diameter of the hole. Therefore, when the shaft portion 84b moves downward, the stopper portion 84c contacts the edge of the through-hole, and the downward movement of the valve body 84a is restricted.

[0092] The pressure of the internal space of the storage chamber 13 acts on the upper surface of the valve body 84a, and the pressure of the lower upstream space S1 acts on the lower surface of the valve body 84a. When the pressure of the internal space of the storage chamber 13 is greater than the pressure of the lower upstream space S1, the valve body 84a moves downward, and the opening at the radially inner and lower end of the discharge flow path 13b is opened. On the other hand, when the flow rate of the blow-by gas B1 flowing into the lower upstream space S1 increases and the pressure of the blow-by gas B1 acting on the lower surface of the valve body 84a increases, the valve body 84a moves upward, and the opening at the radially inner and lower end of the discharge flow path 13b is closed.

[0093] <<Leaf spring>> The leaf spring 80 is a member that generates a repulsive force proportional to the amount of compression. The leaf spring 80 is a metal annular member formed in a wave shape vertically. Therefore, the leaf spring 80 generates a repulsive force when compressed vertically. One leaf spring 80 is arranged on the upper surface of the disc portion 12e2. The leaf spring 80 is sandwiched between the upper surface of the disc portion 12e2 and the lower surface of the lid portion 3f and is compressed vertically. Thereby, the leaf spring 80 generates a repulsive force and acts a downward force on the collection structure 12 through the disc portion 12e2 and the lower case 11a in which the collection structure 12 is fitted. Further, the repulsive force generated by the leaf spring 80 acts an upward force on the upper case 11b through the lid portion 3f, the small-diameter cylindrical body 3e, and the gas discharge port 3j.

[0094] Due to the leaf spring 80, a downward force acts on the lower case 11a, and an upward force acts on the upper case 11b. Here, the upper case 11b is assembled to the lower case 11a by fitting the hook portion 3b into the claw portion 2d of the lower case 11a. However, due to variations in the dimensions of the hook portion 3b and the claw portion 2d, play may occur in the fitting portion. In contrast, according to the present embodiment, due to the leaf spring 80, a downward force acts on the lower case 11a and an upward force acts on the upper case 11b (that is, a repulsive force in the direction of separating the two cases vertically acts), so the upper case 11b is assembled to the lower case 11a without play.

[0095] [Flow of blow-by gases B1, B2, and oil droplet-like oil L2] Referring to FIGS. 8A and 8B, the flow of the blow-by gases will be described. In FIGS. 8A and 8B, the broken line indicates the flow of the blow-by gas B1, the dashed-dotted line indicates the flow of the blow-by gas B2, and the solid line indicates the flow of the oil droplet-like oil L. In FIGS. 8A and 8B, only the reference numerals necessary for the description are shown from the viewpoint of clarity of the drawing. Here, the blow-by gas B1 refers to the blow-by gas in which mist-like oil is adsorbed to the combustion gas and unburned gas generated in the engine 40, and is located in the cover inner space 41d, the lower upstream space S1, and the first lower downstream space S2. The blow-by gas B2 refers to the blow-by gas in which mist-like oil is adsorbed to the combustion gas and unburned gas generated in the engine 40, and is located in the second lower downstream space S3, the upper upstream space S4, and the upper downstream space S5.

[0096] As shown in FIG. 8A, the blow-by gas B1 flows into the lower upstream space S1 from the cover inner space 41d through the inflow hole 2b.

[0097] When flowing into the lower upstream space S1, part of the blow-by gas B1 collides with the inclined surface portion 82b and the guide portion 82c, and the rest passes through the notch 82d. The flow direction of the blow-by gas B1 changes when it collides with the inclined surface portion 82b and the guide portion 82c. At this time, part of the mist-like oil in the blow-by gas B1 aggregates on the surfaces of the inclined surface portion 82b and the guide portion 82c and is separated from the blow-by gas B1. The blow-by gas B1 from which part of the mist-like oil has been separated passes through the notch 82d. Therefore, the amount of mist-like oil contained in the blow-by gas B1 flowing into the lower upstream space S1 is less than the amount of mist-like oil contained in the blow-by gas B1 in the cover inner space 41d.

[0098] The blow-by gas B1 that has passed through the notch 82d rises toward the adjustment valve 12b. At this time, part of the blow-by gas B1 collides with the wall plate portion 12a5. As a result, part of the mist-like oil aggregates on the surface of the wall plate portion 12a5 and is separated from the blow-by gas B1.

[0099] On the other hand, the mist-like oil separated from the blow-by gas B1 is aggregated by the guide portion 82c to become oil droplet-like oil L. This oil droplet-like oil L flows along the surfaces of the inclined surface portion 82b and the guide portion 82c under the action of gravity and flows into the hole 11e in the lower end surface 11c of the case 11. When the amount of the oil droplet-like oil L flowing into the hole 11e exceeds the volume of the hole 11e, the oil droplet-like oil L overflows from the hole 11e. Since the lower end surface 11c is inclined downward toward the oil discharge port 2c, the oil droplet-like oil L flows along the surface 11d of the lower end surface 11c toward the oil discharge port 2c. In this way, the oil droplet-like oil L continues to contact the inclined surface portion 82b, the guide portion 82c, the side wall surface 11e1 and the bottom wall surface 11e2 of the hole 11e, and the surface 11d of the lower end surface 11c. For this reason, the oil droplet-like oil L flows out into the cover inner space 41d through the oil discharge port 2c.

[0100] Here, the flow rate of the blow-by gas B1 flowing into the lower upstream space S1 varies depending on the operating state of the engine 40 and the like. When the gas flow rate flowing into the lower upstream space S1 is small, the gas pressure in the lower upstream space S1 is low. For this reason, the valve elastic body 12b2 adheres to the upper end opening of the small-diameter cylinder portion 12a2 by the spring force of the spring 12b4, and the upper end opening of the small-diameter cylinder portion 12a2 is in a closed state.

[0101] On the other hand, when the flow rate of the blow-by gas B1 flowing into the lower upstream space S1 increases and the gas pressure in the lower upstream space S1 exceeds a certain magnitude, the upward force acting on the valve body 12b1 due to the gas pressure in the lower upstream space S1 becomes greater than the downward force acting on the valve body 12b1 by the spring 12b4. Therefore, the valve body 12b1 moves upward, the valve elastic body 12b2 is separated upward from the upper end of the small-diameter cylinder portion 12a2, and the upper end opening of the small-diameter cylinder portion 12a2 is in an open state. In this case, the blow-by gas B1 containing mist-like oil flows through the flow path C1 to the first lower downstream space S2. Note that the higher the gas pressure in the lower upstream space S1, the greater the upward movement amount of the valve body 12b1 and the greater the opening degree of the flow path C1.

[0102] The blow-by gas B1 that has passed through the flow path C1 collides with the trapping body 12c facing the outlet of the flow path C1. While the blow-by gas B1 passes through the trapping body 12c, the mist-like oil is trapped by the trapping body 12c. Thereby, the mist-like oil is separated from the blow-by gas B1. The blow-by gas B2 after passing through the trapping body 12c and having the mist-like oil separated therefrom flows to the second lower downstream space S3.

[0103] The blow-by gas B2 flows from the second lower downstream space S3 to the upper upstream space S4. Here, if the PCV valve 3k is in a closed state, the blow-by gas B2 stays in the upper upstream space S4. On the other hand, if the PCV valve 3k is in an open state, the blow-by gas B2 flows to the upper downstream space S5. Then, the blow-by gas B2 flows through the gas discharge port 3j to the breather pipe 20.

[0104] Since the upper downstream space S5 is connected to the intake pipe 30 through the gas discharge port 3j and the breather pipe 20, when the intake pressure (negative pressure) of the engine 40 increases and the force pulling the valve part 3kv of the diaphragm valve 3k1 downward becomes greater than the elastic force of the spring 3k2, the opening degree of the PCV valve 3k becomes smaller. Further, when the intake pressure of the engine 40 becomes even higher, the valve part 3kv comes into contact with the opening 3g of the small-diameter cylindrical body 3e, and the PCV valve 3k closes completely. On the other hand, when the intake pressure of the engine 40 decreases and the elastic force of the spring 3k2 becomes greater than the force pulling the valve part 3kv downward, the opening degree of the PCV valve 3k becomes larger.

[0105] The mist-like oil separated from the blow-by gas B1 by the trapping body 12c also aggregates into oil droplet-like oil L. This oil droplet-like oil L flows from the trapping body 12c to the second lower downstream space S3 by gravity. The oil droplet-like oil L that has flowed into the second lower downstream space S3 further flows to the lower storage chamber 13 below through the gap 13c due to the action of gravity.

[0106] The oil droplet-like oil L flows through the discharge passage 13b of the storage chamber 13 to the opening at the radially inner and lower end of the discharge passage 13b. When the pressure in the lower upstream space S1 on the lower surface side of the valve body 84a is higher than the pressure in the discharge passage 13b on the upper surface side of the valve body 84a, the valve body 84a is pushed up and the above opening closes. For this reason, the blow-by gas B1 flowing into the lower upstream space S1 does not flow into the discharge passage 13b. While the engine 40 is operating, the amount of blow-by gas B1 flowing into the lower upstream space S1 increases, so the pressure in the lower upstream space S1 increases. Therefore, usually, while the engine 40 is operating, the opening at the radially inner and lower end of the discharge passage 13b is closed.

[0107] On the one hand, when the pressure in the discharge passage 13b is higher than or the same as the pressure in the lower upstream space S1, the valve body 84a is pushed down, and the opening at the radially inner and lower end of the discharge passage 13b opens. When the engine 40 stops, the amount of blow-by gas B1 flowing into the lower upstream space S1 decreases, so the pressure in the lower upstream space S1 decreases. Therefore, usually, while the engine 40 is stopped, the above opening is open. At this time, the oil droplet-shaped oil L flows into the lower upstream space S1 through the above opening. Then, the oil droplet-shaped oil L flows to the lower end surface 11c of the lower case 11a and flows into the cover inner space 41d through the oil discharge port 2c.

[0108] (Modification example) Next, the oil separator 100 according to the modification example of the embodiment will be described. The oil separator 100 according to the modification example is different from the oil separator 10 according to the above embodiment in that no hole is formed in the lower end surface 11c1 of the lower case 11a1 and the guide portion 83c of the oil trap 83 contacts the lower end surface 11c. Hereinafter, the components having the same or similar functions as those of the oil separator 10 according to the embodiment are denoted by the same reference numerals as those of the oil separator 10, and the description thereof is omitted, and the different parts will be described.

[0109] FIG. 9 is a partially enlarged view of the oil separator 100 according to the modification example. As shown in FIG. 9, with the oil trap 82 positioned with respect to the case 11, the tip 82e of the guide portion 83c contacts the lower end surface 11c1 of the lower case 11a1.

[0110] <Flow of oil droplet-shaped oil L> The mist-like oil that collides with the inclined surface portion 82b and the guide portion 83c and is separated from the blow-by gas B1 is aggregated by the guide portion 82c to become oil-droplet-like oil L. This oil-droplet-like oil L flows along the surfaces of the inclined surface portion 82b and the guide portion 83c by the action of gravity and reaches the surface 11d of the lower end surface 11c1 of the case 11. Since the lower end surface 11c is inclined downward toward the oil discharge port 2c, the oil-droplet-like oil L flows along the surface 11d of the lower end surface 11c1 toward the oil discharge port 2c. In this way, the oil-droplet-like oil L continues to contact the inclined surface portion 82b, the guide portion 83c, and the surface 11d of the lower end surface 11c1. For this reason, the oil-droplet-like oil L flows out into the cover inner space 41d through the oil discharge port 2c.

[0111] In the above-described embodiments and modifications, the following aspects are disclosed.

[0112] (Aspect 1) The oil separators 10, 100 include cases 11, 110 attached to the engine 40, and oil traps 82, 83 housed in the cases 11, 110 for separating mist-like oil from the blow-by gas B1 generated by the engine 40. The oil traps 82, 83 are arranged with a predetermined interval W2 and have a plurality of guide portions 82c, 83c against which the blow-by gas B1 collides. The tips 82e of the guide portions 82c, 83c contact the lower end surface 11c1 of the case 110 or are arranged in holes 11e formed in the lower end surface 11c of the case 11.

[0113] In a conventional oil separator, there was no guide portion, and the lower end of the inclined surface portion of the oil trap was spaced upward from the lower case. For this reason, a gap was formed between the lower end of the inclined surface portion and the lower case. When blow-by gas containing mist-like oil flowed into the lower case, the blow-by gas collided with the inclined surface portion. The mist-like oil separated from the blow-by gas aggregated into oil droplet-like oil. This oil droplet-like oil reached the lower end surface of the lower case from the lower end of the inclined surface portion through the above gap due to the action of gravity. This oil droplet-like oil may have been adsorbed again by the blow-by gas passing through the gap while passing through the gap.

[0114] On the other hand, according to the oil separators 10 and 100 of Embodiment 1, the mist-like oil contained in the blow-by gas that has collided with the inclined surface portion 82b and the guide portion 82c is aggregated by the guide portion 82c to become oil droplet-like oil L. Then, the oil droplet-like oil L continues to contact the inclined surface portion 82b, the guide portion 82c, the side wall surface 11e1 and the bottom wall surface 11e2 of the hole 11e, and the surface 11d of the lower end surface 11c until it is discharged from the oil discharge port 2c. For this reason, the oil droplet-like oil L flows into the oil discharge port 2c without being adsorbed again by the blow-by gas B1 passing through the notch 82d. Therefore, more mist-like oil can be separated from the blow-by gas B1.

[0115] (Embodiment 2) In Embodiment 1, the tip 82e of the guide portion 82c is arranged with a gap between it and the hole 11e.

[0116] According to the oil separator 10 of Embodiment 2, the oil droplet-like oil L can be stored in the hole 11e. Since the oil droplet-like oil L stored in the hole 11e has a mass corresponding to the volume of the hole 11e, it flows into the oil discharge port 2c without being adsorbed again by the blow-by gas B1 passing through the notch 82d. Therefore, more mist-like oil can be separated from the blow-by gas B1.

[0117] (Embodiment 3) In Embodiment 1 or 2, the number of the guide portions 82c and 83c is equal to or greater than the number of the inflow holes 2b formed in the lower cases 11a and 11a1.

[0118] According to the oil separators 10 and 100 of Embodiment 3, it becomes easier to aggregate the mist-like oil contained in the blow-by gas B1 that has passed through the inflow holes 2b. For this reason, the amount of the mist-like oil separated from the blow-by gas B1 can be increased.

[0119] (Embodiment 4) In any one of Embodiments 1 to 3, at least one of the guide portions 82c and 83c is disposed at least partially opposite to the inflow holes 2b formed in the lower cases 11a and 11a1.

[0120] According to the oil separators 10 and 100 of Embodiment 4, it becomes easier to aggregate the mist-like oil contained in the blow-by gas B1 that has passed through the inflow holes 2b. For this reason, the amount of the mist-like oil separated from the blow-by gas B1 can be increased.

[0121] (Embodiment 5) In any one of Embodiments 1 to 4, the width W1 of the guide portions 82c and 83c is equal to the predetermined interval W2.

[0122] If the width W1 of the guide portions 82c and 83c is smaller than the predetermined interval W2, most of the blow-by gas B1 that has passed through the inflow holes 2b passes between the guide portions 82c and 83c (that is, the notch 82). For this reason, the amount of the mist-like oil aggregated by the guide portions 82c and 83c decreases. As a result, the amount of the mist-like oil separated from the blow-by gas B1 decreases.

[0123] On the other hand, if the width W1 of the guide portions 82c and 83c is larger than the predetermined interval W2, the flow velocity of the blow-by gas B1 passing between the guide portions 82c and 83c (that is, the notch 82d) increases. For this reason, the oil droplet-like oil L is likely to be adsorbed again to the blow-by gas B1.

[0124] On the other hand, according to the oil separators 10 and 100 of Embodiment 5, while ensuring the amount of mist-like oil aggregated by the guide portions 82c and 83c, it is possible to suppress the flow rate of the blow-by gas B1 passing between the guide portions 82c and 83c (i.e., the notch 82d) from becoming too high. Therefore, more mist-like oil can be separated from the blow-by gas B1.

[0125] (Embodiment 6) In any one of Embodiments 1 to 5, the lower end surfaces 11c and 11c1 of the cases 11 and 110 are formed to be inclined downward, and the surfaces 11d of the lower end surfaces 11c and 11c1 are formed to be flat.

[0126] For example, when there are protrusions on the surface 11d of the lower end surfaces 11c and 11c1, when the oil droplet-like oil L gets over the protrusions, the oil droplet-like oil L may be separated from the surface 11d. In this case, the oil droplet-like oil L is likely to be adsorbed by the blow-by gas B1 again.

[0127] On the other hand, according to the oil separators 10 and 100 of Embodiment 6, since the surface 11d of the lower end surfaces 11c and 11c1 is flat, the oil droplet-like oil L continues to contact the surface 11d until it is discharged from the oil discharge port 2c. For this reason, the oil droplet-like oil L flows toward the oil discharge port 2c without being adsorbed by the blow-by gas B1 passing through the notch 82d again. Therefore, more mist-like oil can be separated from the blow-by gas B1.

[0128] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the oil separators 10 and 100 according to the above embodiments, and includes all aspects included in the concept and claims of the present invention. Also, in order to achieve the above-described problems and effects, each configuration may be selectively combined as appropriate. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments can be appropriately changed according to the specific aspects of the present invention.

Description of Reference Numerals

[0129] 2b Inlet hole, 11 Case, 11c, 11c1 Lower end surface, 11d Surface, 11e Hole, 40 Engine, 82, 83 Oil trap, 82c, 83c Guide portion, 82e Tip, B1 Blow-by gas containing mist-like oil (gas containing mist-like oil), W1 Width of the guide portion, W2 Predetermined interval,

Claims

1. A case attached to an engine, and an oil trap housed in the case for separating mist-like oil from gas containing the mist-like oil generated by the engine, comprising: the oil trap having a plurality of guide portions arranged at a predetermined interval for aggregating mist-like oil contained in the gas; the tip of the guide portion contacts the lower end surface of the case, or is disposed in a hole formed in the lower end surface of the case, characterized in that it is an oil separator.

2. The tip of the guide portion is disposed with a gap between it and the hole, The oil separator according to Claim 1.

3. The number of the guide portions is equal to or greater than the number of inlet holes formed in the case, The oil separator according to Claim 1.

4. At least one of the guide portions is disposed at least partially opposite to the inlet hole formed in the case, The oil separator according to Claim 1.

5. The width of the guide portion is equal to the predetermined interval, The oil separator according to Claim 1.

6. The lower end surface of the case is formed to be inclined downward, The surface of the lower end surface is formed to be flat, The oil separator according to Claim 1.

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