CN112648044A

CN112648044A - Oil separator

Info

Publication number: CN112648044A
Application number: CN201910964181.2A
Authority: CN
Inventors: 冈本有司; 石田耕作; 伊藤笃志
Original assignee: Tokyo Roki Co Ltd
Current assignee: Tokyo Roki Co Ltd
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2021-04-13
Anticipated expiration: 2039-10-11
Also published as: CN112648044B

Abstract

The present invention makes the emulsified oil easy to flow. An oil separator for separating mist oil from a gas containing the mist oil, the oil separator comprising: a housing (20) having an interior space; a plurality of separation discs (63) stacked in the vertical direction in the internal space and rotating around a vertical axis; a lower holder (72) that holds the separation disk (63) from below, extends outward from the outer peripheral edge of the separation disk (63), and rotates together with the separation disk (63); and a guide portion (72c) which is provided on the lower holder (72) at a position radially outward of the outer peripheral edge of the separation disc (63) and which is inclined downward toward the radially outward side.

Description

Oil separator

Technical Field

The present invention relates to an oil separator for separating mist oil contained in gas from the gas.

Background

Patent documents 1 and 2 disclose oil separators for separating mist oil from blow-by gas. A plurality of separation discs are stacked inside a casing of the oil separator. When blow-by gas is supplied from the engine to the central portion of the separation discs, the blow-by gas passes through the gaps between the separation discs to the outside, and at this time, mist oil in the blow-by gas is captured by the gaps. The trapped oil flies outward from the gap by centrifugal force and collides with the inner circumferential surface of the casing. The oil flows down along the inner peripheral surface of the casing and is discharged to the outside of the casing.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4699668 (JP 4699668B 2)

Patent document 2: specification of U.S. Pat. No. 7338546 (US 7338546B 2)

Disclosure of Invention

Problems to be solved by the invention

However, when the oil separator is used in a cold place, the oil flying out from the gaps of the separation discs is emulsified. If the oil is emulsified, the fluidity of the oil is reduced, and the oil is not discharged.

The present invention has been made in view of such circumstances, and an object thereof is to facilitate the flow of emulsified oil.

Means for solving the problems

In order to solve the above problem, an oil separator for separating mist oil from a gas containing the mist oil includes: a housing having an interior space; a plurality of separation discs stacked in the vertical direction in the internal space and rotating around a vertical axis; a lower holder that holds the separation disk from below, extends radially outward from an outer peripheral edge of the separation disk, and rotates together with the separation disk; and a guide portion provided on the lower holder at a position radially outward of an outer peripheral edge of the separation disk and inclined downward toward the radially outward side.

As described above, a vortex flow flowing in the circumferential direction from the outer edge of the separation disc toward the outside is generated by the rotation of the separation disc. Since the vortex flows along the upper surface of the guide portion in the vicinity of the guide portion, the vortex also contains a downward component. Therefore, the emulsion entering the gap between the inner peripheral surface of the housing and the guide portion is pushed out downward by the wind pressure of the downward component of the vortex. Therefore, the emulsion flows and is discharged easily.

Preferably, an angle formed by an upper surface of the guide portion and an inner circumferential surface of the housing is acute.

In particular, if the angle formed by the upper surface of the guide portion and the inner peripheral surface of the housing is an acute angle, the air pressure that presses the emulsion entering the gap between the inner peripheral surface of the housing and the guide portion downward increases.

Preferably, the oil separator further includes a standing wall portion standing from an outer edge portion of the lower bracket, and the guide portion extends radially outward from an upper end of the standing wall portion.

Preferably, the oil separator includes: a partition member provided in the internal space and partitioning the internal space into an upper separation chamber and a lower injection chamber; a main shaft vertically penetrating the partition member and provided to be rotatable about a vertical axis; and a nozzle that projects from an outer peripheral surface of the main shaft in the injection chamber and injects oil, wherein the separation disk, the lower holder, and the guide portion are disposed in the separation chamber, and the separation disk and the lower holder are attached to the main shaft, and the separation disk, the lower holder, and the guide portion are rotated together with the main shaft by injecting the oil from the nozzle, thereby separating the mist-like oil from the gas, wherein an oil hole that leads from the separation chamber to the injection chamber is formed in the partition wall member, and an oil discharge port that leads from an outer side of the housing to the injection chamber is provided in the housing.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the emulsion entering the gap between the inner peripheral surface of the housing and the guide portion is pushed out downward by the downward wind pressure. Therefore, the emulsion flows and is discharged easily.

Drawings

FIG. 1 is a diagrammatic view illustrating a closed crankcase ventilation system.

Fig. 2 is a perspective view of the oil separator viewed from above.

Fig. 3 is an exploded perspective view of the oil separator exploded and overlooked.

Fig. 4 is a top view of the oil separator.

Fig. 5 is a sectional view of a section of fig. 4 taken along line V-V.

Fig. 6 is an enlarged view of the upper portion of fig. 5.

Fig. 7 is an enlarged view of the middle of fig. 5.

Fig. 8 is an enlarged view of the lower portion of fig. 5.

Fig. 9 is a sectional view showing a section of the cut portion on line IX-IX in fig. 5.

Description of the symbols

2-oil separator, 20-housing, 21 a-oil discharge port, 23 a-exhaust port, 31-lower partition member (partition member), 43-separation chamber, 44-injection chamber, 52-main shaft, 53-nozzle, 63-separation disc, 72-lower holder, 72 b-standing wall, 72 c-guide.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, various technically preferable limitations for carrying out the present invention are added, but the scope of the present invention is not limited to the following embodiments and the illustrated examples.

1. Closed crankcase ventilation system

As shown in fig. 1, a closed crankcase ventilation system 1 includes an oil separator 2, a breather pipe 3, a gas supply pipe 5, and an oil supply pipe 10. The oil separator 2 is mounted on the side of the engine 4. The gas supply pipe 5 is connected to the engine 4 and the oil separator 2, and blow-by gas discharged from a crankcase of the engine 4 is supplied to the oil separator 2 through the gas supply pipe 5. The blow-by gas supplied from the crankcase of the engine 4 to the oil separator 2 contains mist oil. The oil separator 2 separates mist oil from the blow-by gas.

The breather pipe 3 is connected between the upper portion of the oil separator 2 and the intake-side flow passage 6 of the engine 4. The separated blow-by gas discharged from the oil separator 2 flows back to a portion of the intake-side flow passage 6 where the air filter 7 is connected to the turbocharger 8. The returned blow-by gas is mixed with fresh air from the air filter 7. The mixture of the blowby gas and the fresh air is compressed by the turbocharger 8. After that, the mixture gas is cooled by the charge cooler 9 and then supplied to the engine 4.

The oil supply pipe 10 is connected between the lower portion of the oil separator 2 and the engine 4, and the working oil sent from the engine 4 is supplied to the oil separator 2 through the oil supply pipe 10. The flow of the working oil supplied to the oil separator 2 is used as power for the oil separator 2, and the oil separator 2 (particularly, a rotor unit 50 described below) operates using the power. The working oil supplied to the oil separator 2 is lubricating oil used in the engine 4. When the oil separator 2 is operated by the hydraulic oil, the mist oil is separated from the blow-by gas. The separated mist oil is mixed with the working oil in the oil separator 2. The mixed oil is discharged from the oil separator 2 to the engine 4.

In the present embodiment, even if the separated oil is emulsified, the emulsified oil is easily discharged. Before explaining a mechanism for easily discharging emulsified oil, the structure of the oil separator 2 will be described.

2. Outline of oil separator

The oil separator 2 will be described with reference to fig. 2 to 9.

As shown in fig. 2 to 5, the oil separator 2 includes a casing 20, a lower partition member 31, an intermediate partition member 32, an upper partition member 33, a rotor unit 50, and a PCV valve 90. The housing 20 has a lower case 21, an upper case 22, and a top cover 23. The case 20 is assembled by attaching the lower case 21 and the top cover 23 to the upper case 22, and an internal space is formed inside the case 20. The lower partition member 31, the intermediate partition member 32, the partition wall 22a, and the upper partition member 33 are provided inside the housing 20, and the internal space of the housing 20 is partitioned by the lower partition member 31, the intermediate partition member 32, the partition wall 22a, and the upper partition member 33. The rotor unit 50, the PCV valve 90, and the like are assembled to the casing 20 in a state of being housed in the internal space of the casing 20.

Hereinafter, unless otherwise specified, the axial direction indicates a direction parallel to the rotation axis of the rotor unit 50, the circumferential direction indicates a circumferential direction around the rotation axis of the rotor unit 50, and the radial direction indicates a direction perpendicular to the rotation axis of the rotor unit 50. In a state where the oil separator 2 is attached to the engine 4, the rotation axis of the rotor unit 50 extends in the vertical direction.

3. Outer shell and inner side dividing area thereof

The case 20 and the internal space thereof will be described, and the division of the internal space of the case 20 by the lower partition member 31, the middle partition member 32, the partition member 22a, and the upper partition member 33 will be described.

As shown in fig. 3 and 5 to 8, the upper case 22 is formed in a cylindrical shape, and the upper surface and the lower surface of the upper case 22 are open. A partition wall 22a is provided in an upper portion of the inside of the upper case 22, and the hollow portion of the upper case 22 is partitioned into a space above and a space below the partition wall 22a by the partition wall 22 a.

An intake port 24 is provided in a portion of the upper case 22 below the partition wall 22 a. The gas inlet 24 is connected to the gas supply pipe 5 (see fig. 1 and 3). Therefore, the blow-by gas is introduced from the engine 4 through the gas supply pipe 5 and the intake port 24 into a portion (specifically, an introduction passage 41 described below) of the internal space of the housing 20 below the partition wall portion 22 a.

A middle partition wall member 32 is provided inside the upper case 22 at a position spaced downward from the disk-shaped partition wall member 22 a. The peripheral edge of the intermediate partition member 32 is attached to the inner peripheral surface of the upper case 22, and the hollow portion of the upper case 22 is vertically divided by the intermediate partition member 32. A cylindrical fitting portion 32b is provided in a central portion of the lower surface of the intermediate partition member 32 so as to protrude downward. The hollow portion of the fitting portion 32b opens at the upper surface of the intermediate partition member 32, and also opens at the lower end of the fitting portion 32 b. In the opening at the lower end of the fitting portion 32b, a support portion 32d is provided radially from the center of the opening at the lower end of the fitting portion 32b to the inner peripheral surface of the fitting portion 32b, and the support portion 32d is provided. Since the support portions 32d are provided radially, the flow holes 32e are formed in the support portions 32 d. Therefore, the hollow portion of the fitting portion 32b passes downward through the flow hole 32 e. Further, the support portion 32d supports the upper end of the spindle shaft 51 described below.

A partition portion 22c is provided in a protruding state on the lower surface of the partition portion 22a, and the lower end of the partition portion 22c abuts on the upper surface of the intermediate partition member 32. As shown in fig. 9, the partition portion 22c partitions the space between the intermediate partition member 32 and the partition portion 22a into an introduction passage 41 and a first cavity 42 surrounding the introduction passage 41. The air inlet 24 communicates the outside of the upper case 22 with the introduction passage 41. As shown in fig. 5 and 6, the flow hole 32e communicates the introduction passage 41 with the space below the intermediate partition member 32. The blow-by gas is introduced from the engine 4 into the introduction passage 41 through the gas supply pipe 5 and the intake port 24, and the introduced blow-by gas is sent to the lower side of the intermediate partition member 32 through the introduction passage 41 and the fitting portion 32b and through the flow hole 32 e.

The partition 22a is provided with a second communication hole 22d (see fig. 9 in particular), and the second communication hole 22d vertically penetrates the partition 22 a. The second communication hole 22d is located outside the partition 22c, and the second communication hole 22d communicates the first chamber 42 with the hollow portion above the partition 22 a. On the other hand, the upper side of the introduction passage 41 is closed by the partition wall 22a, and the hollow portion above the partition wall 22a is separated from the introduction passage 41 by the partition wall 22 a.

As shown in fig. 5 and 6, the first communication holes 32c penetrate the peripheral edge of the intermediate partition member 32 in the vertical direction. The first communication hole 32c is located outside the partition portion 22c, and the first communication hole 32c communicates the first chamber 42 with the hollow portion below the middle partition member 32.

As shown in fig. 5, 7, and 8, a lower partition member 31 is attached to the lower end of the upper case 22, and the lower opening of the upper case 22 is closed by the lower partition member 31. The lower partition member 31 is spaced downward from the intermediate partition member 32, and a separation chamber 43 is formed between the intermediate partition member 32 and the lower partition member 31. The separation chamber 43 is a part of a hollow portion in the upper housing 22. In the separation chamber 43, the mist oil gas is separated from the blow-by gas by the rotor 60, and the blow-by gas is introduced from the intake port 24 to the rotor 60 of the rotor unit 50 described below through the introduction passage 41, the fitting portion 32b, and the flow hole 32 e.

As shown in fig. 5 and 6, an upper partition member 33 is attached to the upper end of the upper case 22, and the upper opening of the upper case 22 is closed by the upper partition member 33. The upper partition member 33 is spaced upward from the partition wall 22a, and a second chamber 45 is formed between the upper partition member 33 and the partition wall 22 a. An opening 33a is formed in the center of the upper partition member 33, and the opening 33a penetrates the upper partition member 33 in the vertical direction.

A top cover 23 is attached to the upper end of the upper case 22. The top cover 23 covers the upper partition member 33 from above the upper partition member 33, and the peripheral edge of the upper partition member 33 is sandwiched between the lower end of the top cover 23 and the upper end of the upper case 22. The top cover 23 is formed in a dome shape, and a third chamber 46 is formed inside the top cover 23. The third chamber 46 and the second chamber 45 are partitioned by an upper partition member 33, and an opening 33a communicates the second chamber 45 with the third chamber 46.

An exhaust port 23a is provided in the top cover 23, and the exhaust port 23a communicates the outside of the top cover 23 with the third chamber 46. The vent 23a is connected to the breather pipe 3, and the separated blow-by gas in the third chamber 46 is discharged to the intake-side flow path 6 through the third chamber 46 and the breather pipe 3.

As shown in fig. 5, 7 and 8, a lower case 21 is attached to a lower end of the upper case 22. The lower case 21 is covered with the lower partition member 31 from below the lower partition member 31, the upper end of the lower case 21 is fitted into the opening at the lower end of the upper case 22, and the lower case 21 and the upper case 22 are fixed by bolts or the like. The peripheral edge of the lower partition member 31 is sandwiched between the upper end of the lower case 21 and the lower end of the upper case 22. The lower case 21 is formed in a bottomed box shape with an open upper surface. The lower partition member 31 partitions the injection chamber 44 in the lower case 21 and the separation chamber 43 in the upper case 22. A through hole 31a through which the rotor unit 50 passes is formed in the center of the lower partition member 31.

A tubular oil-proof cover 31g hanging downward is provided on the lower surface of the lower partition member 31. The oil-proof cover 31g surrounds the periphery of the through hole 31 a.

A plurality of oil holes 31c are formed in the lower partition member 31 at predetermined intervals in the circumferential direction. The oil hole 31c is disposed around the oil shield 31 g. The oil separated from the blow-by gas flows from the separation chamber 43 into the injection chamber 44 through the oil hole 31 c.

4. Path of leakage

As indicated by arrows in fig. 5, the blow-by gas introduced from the engine 4 to the intake port 24 flows in this order through the introduction passage 41, the fitting portion 32b, the flow hole 32e, the rotor 60, the separation chamber 43, the first communication hole 32c, the first chamber 42, the second communication hole 22d, the second chamber 45, the opening 33a, and the third chamber 46, and is discharged from the exhaust port 23a to the breather pipe 3.

5. Oil introduction passage and oil discharge port

As shown in fig. 5 and 8, the lower case 21 is formed with an oil discharge port 21 a. The oil discharge port 21a is opened in a side surface of the lower housing 21 and communicates with the inside of the injection chamber 44. The oil discharge port 21a is connected to the engine 4, and the oil in the injection chamber 44 is discharged to the engine 4 through the oil discharge port 21 a.

A projection 21b is provided on the bottom surface of the lower case 21. An oil introduction path 21c is formed in the projection 21 b. The oil introduction passage 21c is provided to extend downward from the upper surface of the boss 21b, and is branched in the lateral direction to the side surface of the lower case 21, one end of the oil introduction passage 21c is opened to the side surface of the lower case 21, and the other end of the oil introduction passage 21c is opened to the upper surface of the boss 21 b. The oil introduction passage 21c is connected to the oil supply pipe 10 (see fig. 1 and 3) on the side surface of the lower housing 21. Therefore, the working oil is introduced from the engine 4 into the oil introduction passage 21c through the oil supply pipe 10.

A mesh filter 35 for filtering the working oil is provided in the middle of the oil introduction passage 21 c. By removing the plug 35a from the lower end of the lower case 21, the lower end of the oil introduction passage 21c is opened, and the filter 35 can be removed from the oil introduction passage 21 c.

6. Rotor unit and working oil

As shown in fig. 3, 5, 7, and 8, the rotor unit 50 is a mechanism for separating the mist oil from the blow-by gas. The rotor unit 50 includes a spindle (spindle) 51, a spindle (spindle)52, a rotor 60, a plurality of nozzles 53, and the like.

The spindle shaft 51 extends vertically in the lower case 21 and the upper case 22, and vertically penetrates the through hole 31a of the lower partition member 31. The lower end of the spindle shaft 51 is inserted into the upper end of the oil introduction passage 21 c. The upper end portion of the spindle shaft 51 is supported by the support portion 32 d. A first oil supply passage 51b is formed inside the spindle shaft 51 along the center line of the spindle shaft 51. The lower end of the first oil supply passage 51b opens at the lower end surface of the spindle shaft 51, and the first oil supply passage 51b communicates with the oil introduction passage 21 c. The upper portion of the first oil supply passage 51b is branched into a plurality of parts radially outward at the intermediate portion of the spindle shaft 51, and the end portion of the first oil supply passage 51b opens at the outer peripheral surface of the spindle shaft 51.

The spindle shaft 51 is inserted into a cylindrical spindle 52, and the spindle 52 also vertically penetrates through the through hole 31a of the lower partition member 31. An upper portion of the main shaft 51 protrudes upward from an upper end of the main shaft 52, and a lower portion of the main shaft 51 protrudes downward from a lower end of the main shaft 52. A gap, which is a second oil supply passage 52a, is formed between the outer peripheral surface of the spindle shaft 51 and the inner peripheral surface of the spindle 52. The hydraulic oil introduced into the oil introduction passage 21c is supplied to the second oil supply passage 52a through the first oil supply passage 51 b.

At the lower end portion of the main shaft 52, the main shaft spindle 51 is inserted into a lower bushing 55, and the lower bushing 55 is sandwiched between the outer peripheral surface of the main shaft spindle 51 and the inner peripheral surface of the main shaft 52. At the upper end of the spindle 52, the spindle shaft 51 is inserted into an upper bushing 56, and the upper bushing 56 is sandwiched between the outer peripheral surface of the spindle shaft 51 and the inner peripheral surface of the spindle 52.

The radial load of the main shaft 52 is received by the main shaft spindle 51 via the

bushings

55, 56, and the main shaft 52 is supported by the main shaft spindle 51 in a rotatable state. A nut 58 is screwed to an upper end of the spindle shaft 51, and a lower portion of the spindle shaft 51 is inserted into a bush 54 provided on an upper surface of the boss 21 b. A washer 57, an upper bushing 56, the spindle 52, and a lower bushing 55 are interposed between the nut 58 and the bushing 54, and the thrust load of the spindle 52 is received by the bushing 54 and the nut 58.

A slight gap exists between the lower bushing 55 and the bushing 54, between the upper bushing 56 and the washer 57, and between the washer 57 and the nut 58, so that the main shaft 52 and the

bushings

55, 56 can slightly move in the axial direction. Specifically, when the rotor 60 rotates, the main shaft 52 and the

bushes

55 and 56 are raised in the axial direction, and when the rotor 60 stops, the main shaft 52 and the

bushes

55 and 56 are lowered.

A slight gap is formed between the inner peripheral surface of the main shaft 52 and the upper bushing 56, and a part of the hydraulic oil in the second oil supply passage 52a flows out of the main shaft 52 through the gap. Hereinafter, the effluent working oil is referred to as separation oil.

In a state where the main shaft 52 is supported by the main shaft spindle 51, the main shaft 52 passes through the through hole 31a of the lower partition member 31, and the main shaft 52 extends upward from the through hole 31a and downward from the through hole 31 a.

A plurality of nozzles 53 are provided on the outer peripheral surface of the lower portion of the main shaft 52 so as to protrude at equal intervals (for example, at intervals of 120 °) in the circumferential direction. The nozzle 53 is installed to be inclined downward with respect to the axis of the main shaft 52. An ejection port 53a is formed in the circumferential surface of the nozzle 53 near the tip. The injection ports 53a face in the circumferential direction around the axis of the main shaft 52. At the base end of the nozzle 53, the hollow portion of the nozzle 53 communicates with the second oil supply passage 52 a. The hydraulic oil in the second oil supply passage 52a is supplied into the nozzle 53 and is discharged from the discharge port 53 a. The main shaft 52 is rotated by the injection pressure of the working oil. Therefore, the oil is injected from the nozzle 53, and the power for rotating the main shaft 52 is generated by the injection pressure of the oil.

The nozzle 53 is disposed in the injection chamber 44 and inside the oil-proof cover 31 g. The hydraulic oil injected from the injection port 53a of the nozzle 53 is injected toward the oil-proof cover 31 g. Therefore, the working oil does not scatter to the outside of the oil-proof cover 31g and does not enter the oil hole 31 c.

The working oil sprayed to the oil-proof cover 31g drips from the oil-proof cover 31g toward the bottom of the spray chamber 44. The dropped hydraulic oil flows into the oil discharge port 21a and is discharged to the engine 4. Since the injection chamber 44 communicates with the inside of the engine 4 through the oil discharge port 21a, the gas pressure in the injection chamber 44 and the gas pressure in the engine 4 can be adjusted.

Next, the rotor 60 will be described with reference to fig. 3 and 5 to 8. The rotor 60 is a portion for separating the mist oil from the blow-by gas in the separation chamber 43. The rotor 60 has a cylindrical external shape, a central portion of the rotor 60 is a space 62, the central portion space 62 vertically penetrates the rotor 60, and the central portion space 62 is open vertically. The main shaft 52 is inserted into the center portion space 62, and the main shaft 52 and the rotor 60 are coupled to each other. Therefore, the rotor 60 rotates together with the main shaft 52 by the injection pressure of the oil injected from the nozzle 53.

The rotor 60 includes a separator disk group 61, an upper holder 71, a lower holder 72, and a disk holding portion 73.

The separation disc group 61 is constituted by a plurality of separation discs 63, and the separation discs 63 are stacked in the axial direction of the main shaft 52. The separation disk 63 is formed in a shape in which a vertical inverted V-shape separated radially outward from the axis of the main shaft 52 is rotated around the axis. Therefore, an opening is formed in the central portion of the separation disc 63. The separation discs 63 are stacked to form a central space 62 formed of the above-described openings.

Since the separation disk 63 is a rotating body (body of revolution) having an inverted V-shape, the outer peripheral side portion 64 of the separation disk 63 is formed in a truncated conical shape having an apex above the center of the separation disk 63, and the inner peripheral side portion 65 of the separation disk 63 is formed in a truncated conical shape having an apex below the center of the separation disk 63. The inner peripheral side portion 65 is inclined upward toward the radially outer side, and the outer peripheral side portion 64 is inclined downward from the outer edge of the inner peripheral side portion 65 toward the radially outer side. Since the separation discs 63 meander at the boundary portion between the inner circumferential side portion 65 and the outer circumferential side portion 64, the rigidity of the separation discs 63 is increased. Further, the length from the inner circumferential edge of the separation disk 63 to the outer circumferential edge of the separation disk 63 along the surface of the separation disk 63 can be obtained long, and the surface area of the separation disk 63 can be obtained large.

A plurality of convex portions (for example, ribs, protrusions, etc.) are provided on the upper surface, the lower surface, or both surfaces of the separation disk 63. The convex portion abuts on the adjacent separation disk 63, and a gap having a width determined by the height of the convex portion is formed between the adjacent separation disks 63. In fig. 3 and 5 to 8, the separation of the separation discs 63 is shown with a space left, but the actual space is extremely narrow.

The plurality of separation discs 63 described above are assembled to the upper holder 71, the lower holder 72, and the disc holding portion 73, and the rotor 60 is assembled.

The disk holding portion 73 is fitted into the central opening of the separation disk 63, and the separation disk 63 is supported by the disk holding portion 73. The spindle 52 is inserted into the disk holding portion 73, and the spindle 52 is fixed to the disk holding portion 73. The disk holding portion 73 is provided with a plurality of slits radially extending from the inner periphery to the outer periphery of the disk holding portion 73. Therefore, the cavity 73a inside the disk holding portion 73 communicates with the gaps between the separation disks 63 by the plurality of slits of the disk holding portion 73.

The separation disk 63 is sandwiched between the upper holder 71 and the lower holder 72, and a coupling portion 74 (see fig. 3) couples an outer peripheral portion of the upper holder 71 and an outer peripheral portion of the lower holder 72. Thereby, the lower holder 72 supports the stack of separation discs 63 from below, and the upper holder 71 supports the stack of separation discs 63 from above, so that the separation discs 63 are held between the upper holder 71 and the lower holder 72.

An opening 72a is formed in the center of the lower holder 72. The opening 72a is overlapped below the central opening of the lowermost separation disc 63, and the opening 72a becomes an opening of the lower end of the central portion space 62. The main shaft 52 is fitted into an opening 72a of the lower holder 72, and a peripheral edge portion of the opening 72a is fixed to an outer peripheral surface of a lower portion of the main shaft 52 and a lower end of the disk holding portion 73. Thus, the opening 72a is blocked by the main shaft 52.

The lower holder 72 extends radially outward beyond the outer peripheral edge of the separation plate 63, and a standing wall portion 72b is provided at the outer peripheral edge portion of the lower holder 72. The standing wall portion 72b extends along the outer edge of the lower holder 72 and is formed in an annular shape. The diameter of the separation disk 63 is smaller than the diameter of the lower holder 72, and the lower separation disk 63 in the stack of the separation disks 63 is disposed inside the standing wall portion 72 b.

A guide portion 72c serving as a flange is provided at the upper end of the upright wall portion 72 b. The guide portion 72c extends radially outward from the upper end of the upright wall portion 72b, and is inclined downward toward the radially outer side. The inclination angle of the guide portion 72c is equal to that of the outer peripheral side portion 64 of the separation disc 63, or the inclination angle of the guide portion 72c is larger or slightly smaller than that of the outer peripheral side portion 64 of the separation disc 63. Here, the inclination angles of the outer peripheral portion 64 and the guide portion 72c of the separation disc 63 are angles with respect to a plane defined by the circumferential direction and the radial direction.

Since the guide portion 72c is inclined, an angle formed by the upper surface of the guide portion 72c and the inner peripheral surface of the upper case 22 is acute. The inner peripheral surface of the upper case 22 is not a cylindrical surface, but a conical surface that gradually decreases in diameter upward.

Since the diameter of the separation disk 63 is smaller than the diameter of the lower holder 72, the guide portion 72c and the standing wall portion 72b are located radially outward of the outer peripheral edge of the separation disk 63.

The outer peripheral edge of the guide portion 72c is spaced apart from the inner peripheral surface of the upper case 22, and a gap 43a is formed between the outer peripheral edge of the guide portion 72c and the inner peripheral surface of the upper case 22.

An opening 71a is formed in the center of the upper holder 71. The opening 71a is superposed on the central opening of the uppermost separation disk 63, and the opening 71a is an opening at the upper end of the central portion space 62. The edge of the opening 71a is connected to the upper end of the disk holding portion 73, and the cavity 73a inside the disk holding portion 73 communicates with the opening 71 a. The fitting portion 32b of the middle partition member 32 is inserted into the opening 71a of the upper holder 71 in the upper portion and the opening 71a of the cavity 73a, and the hollow portion of the fitting portion 32b communicates with the cavity 73a through the flow hole 32 e. Therefore, the blow-by gas introduced into the inside of the housing 20 through the inlet port 24 flows into the cavity 73a through the introduction passage 41, the hollow portion of the fitting portion 32b, and the flow hole 32 e.

The blow-by gas flowing into the cavity portion 73a flows radially outward in the plurality of slits of the disk holding portion 73, and flows into the gaps between the separation disks 63. The blow-by gas flowing into the gaps between the separation discs 63 flows radially outward. Here, the pressure from the upstream side acts on the blow-by gas flowing into the gaps between the separation discs 63, and in addition, the centrifugal force generated by the rotation of the rotor 60 acts. Then, a suction pressure for sucking the blow-by gas in the introduction passage 41 into the cavity 73a is generated by a centrifugal force generated by the rotation of the rotor 60, and the flow velocity of the blow-by gas is increased.

On the other hand, the separation oil that flows out into the cavity portion 73a from the minute gap between the inner peripheral surface of the main shaft 52 and the upper bushing 56 flows radially outward in the plurality of slits of the disk holding portion 73 together with the blow-by gas, and flows into the gap between the separation disks 63. The oil present in the gaps between the separation discs 63 diffuses on the surfaces of the separation discs 63 due to centrifugal force, and forms an oil film on the surfaces of the separation discs 63, but the oil film is mainly formed on the upper surfaces of the inner circumferential side portions 65 and the lower surfaces of the outer circumferential side portions 64 of the separation discs 63.

When the blowby gas flows through the gaps between the separation discs 63, the mist oil contained in the blowby gas is absorbed by the oil film on the surfaces of the separation discs 63. Thereby, the mist oil in the blow-by gas is captured by the separation pan 63, and the mist oil is separated from the blow-by gas. As described above, since the surface area of the separation discs 63 is large and the number of stacked separation discs 63 is large, the mist oil is easily separated.

In addition, since not only the oil separated from the blow-by gas but also the separation oil flowing out from the second oil supply passage 52a becomes a component of the oil film on the surface of the separation disk 63, a sufficient oil film is formed on the surface of the separation disk 63. Since the mist oil in the blow-by gas is absorbed by such an oil film, the separation efficiency of the mist oil is high.

The oil adhering to the surfaces of the separation discs 63 flows toward the outer peripheral side along the surfaces of the separation discs 63 due to centrifugal force. At the outer peripheral edge of the separation discs 63, the oil adhering to the surfaces of the separation discs 63 flies outward from the gaps between the separation discs 63 due to centrifugal force.

As shown by the arrows in fig. 8, the flying oil adheres to the inner peripheral surface of the upper case 22. The oil flows down while adhering to the inner circumferential surface of the upper housing 22, and passes downward along the gap 43a between the outer circumferential edge of the guide portion 72c and the inner circumferential surface of the upper housing 22. The oil flows into the injection chamber 44 through the oil hole 31 c. This oil is mixed with the working oil in the injection chamber 44 and flows to the oil discharge port 21a while being mixed.

However, in the case where the oil separator 2 is used in a cold region, the water component contained in the blow-by gas is liquefied. In particular, liquefaction of the water component is likely to occur on the inner peripheral surface of the upper case 22, and the liquefied water is mixed with the oil, so that emulsion is likely to occur on the inner peripheral surface of the upper case 22. Thus, the emulsion may be clogged in the gap 43a between the outer peripheral edge of the guide portion 72c and the inner peripheral surface of the upper housing 22. However, in the present embodiment, the emulsion entering the gap 43a is pushed out downward by wind pressure generated by the rotation of the separation disk 63.

Specifically, a vortex flow that flows in the circumferential direction from the outer edge of the separation disc 63 toward the outside is generated by the rotation of the separation disc 63. In the vicinity of the guide portion 72c, the vortex flows along the upper surface of the guide portion 72c, and thus the vortex also contains a downward component. Therefore, the emulsion entering the gap 43a is pushed out downward by the wind pressure of the downward component of the vortex. In particular, if the angle formed by the upper surface of the guide portion 72c and the inner peripheral surface of the housing 20 is an acute angle, the wind pressure that presses the emulsion entering the gap 43a downward becomes high.

The emulsion pushed out downward from the gap 43a flows into the injection chamber 44 through the oil hole 31c, and flows into the oil discharge port 21a together with the working oil.

7. Drain route for separated blow-by gas and PCV valve

The blowby gas in which the mist oil is separated in the gaps between the separation discs 63 is jetted outward from the gaps between the separation discs 63. As shown in fig. 5, the blow-by gas rises in the separation chamber 43 and flows into the first chamber 42 through the first communication hole 32 c. The blowby gas flows from the first chamber 42 into the second chamber 45 through the second communication hole 22 d. Then, the blow-by gas is discharged from the second chamber 45 to the breather pipe 3 through the opening 33a of the upper partition member 33, the third chamber 46, and the exhaust port 23 a. Thereby, the blow-by gas flows back to the engine 4.

As shown in fig. 5 and 6, the flow rate of the blow-by gas flowing from the second chamber 45 to the third chamber 46 is adjusted by the PCV valve 90. This appropriately adjusts the intake pressure of the engine 4 and the pressure on the crankcase side.

The PCV valve 90 is mounted within the second chamber 45. The PCV valve 90 includes a diaphragm 91, an upper spring 92, and a lower spring 93. The diaphragm 91 is an elastically deformable disk-shaped valve element. The diaphragm 91 is housed in the second chamber 45 and is disposed below the opening 33a of the upper partition member 33. The outer edge of the diaphragm 91 is joined to the upper surface of the partition wall 22 a. Since the second communication holes 22d of the partition portion 22a are disposed outside the outer edge portion of the diaphragm 91, the blow-by gas passing through the second communication holes 22d flows over the diaphragm 91.

The upper spring 92 is sandwiched between the diaphragm 91 and the upper partition member 33 above the central portion of the diaphragm 91. The lower spring 93 is sandwiched between the diaphragm 91 and the partition wall 22a below the central portion of the diaphragm 91. The center portion of the diaphragm 91 is sandwiched between the upper spring 92 and the lower spring 93, and the center portion of the diaphragm 91 is movably supported by the upper spring 92 and the lower spring 93.

The upper case 22 has a pressure regulating hole 22b, and the pressure regulating hole 22b communicates the space below the diaphragm 91 with the outside of the upper case 22. Therefore, the space below the diaphragm 91 is at atmospheric pressure due to the pressure regulating hole 22 b.

The flow rate of the blow-by gas passing through the opening 33a is adjusted as follows. That is, when the intake pressure (negative pressure) of the engine 4 is too high, the central portion of the diaphragm 91 moves upward, and therefore the opening degree of the opening 33a is small, and the flow rate of the blow-by gas decreases. On the other hand, when the pressure on the crankcase side is high, the central portion of the diaphragm 91 moves downward, the opening degree of the opening 33a increases, and the flow rate of the blow-by gas increases. Thereby, the flow rate of the blow-by gas is appropriately adjusted by the diaphragm 91. Also, the pressure of the engine 4, particularly the crankcase, is also appropriately adjusted.

Further, the PCV valve 90 may not be provided.

8. Advantageous effects

Since the guide portion 72c is inclined, the vortex that flows from the outer edge of the separation disc 63 toward the outside and in the circumferential direction due to the rotation of the separation disc 63 also includes a downward component. Therefore, the emulsion entering the gap 43a is pushed out downward by the wind pressure of the downward component of the vortex. Thus, the pushed-out emulsion flows into the injection chamber 44 through the oil hole 31c, and is discharged through the oil discharge port 21a together with the working oil.

Claims

1. An oil separator for separating mist oil from a gas containing the mist oil, the oil separator comprising:

a housing having an interior space;

a plurality of separation discs stacked in the vertical direction in the internal space and rotating around a vertical axis;

a lower holder that holds the separation disk from below, extends radially outward from an outer peripheral edge of the separation disk, and rotates together with the separation disk; and

and a guide portion provided on the lower holder at a position radially outward of an outer peripheral edge of the separation disk and inclined downward toward the radially outward side.

2. The oil separator of claim 1,

an angle formed by the upper surface of the guide portion and the inner circumferential surface of the housing is an acute angle.

3. The oil separator according to claim 1 or 2,

further comprises a standing wall part standing from the outer edge part of the lower bracket,

the guide portion extends radially outward from an upper end of the standing wall portion.

4. The oil separator according to claim 1 or 2, comprising:

a partition member provided in the internal space and partitioning the internal space into an upper separation chamber and a lower injection chamber;

a main shaft vertically penetrating the partition member and provided to be rotatable about a vertical axis; and

a nozzle which is provided in the injection chamber so as to protrude from an outer peripheral surface of the main shaft and injects oil,

the separation disk, the lower holder, and the guide portion are disposed in the separation chamber, and the separation disk and the lower holder are attached to the spindle,

the oil is sprayed from the nozzle to rotate the separation disk, the lower holder, and the guide portion together with the main shaft, thereby separating the atomized oil from the gas,

the partition member is formed with an oil hole leading from the separation chamber to the injection chamber,

the housing is provided with an oil discharge port leading from the outside of the housing to the injection chamber.