oil separator
The oil separator addresses clogging issues by incorporating a collection structure with a valve and breathable collector to manage gas flow and pressure, enhancing the efficiency and durability of oil separation.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOKYO ROKI CO LTD
- Filing Date
- 2022-07-21
- Publication Date
- 2026-07-28
AI Technical Summary
Existing oil separators accumulate dust and become clogged due to the inertia of dust particles colliding with the collection body, leading to inefficiencies in separating mist-like oil from gas.
An oil separator design featuring a collection structure with a main body, valve, and breathable collector, which includes an upstream space, flow path, and downstream space, allowing for controlled gas flow and reduced clogging by utilizing a check valve and elastic components to manage pressure and flow.
The design effectively reduces clogging, ensuring efficient separation of mist-like oil from gas, maintaining the separator's functionality and performance over time.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an oil separator.
Background Art
[0002] An oil separator that separates mist-like oil from gas containing mist-like oil such as blow-by gas of an engine is known. For example, Patent Document 1 discloses an oil separator that employs an impacter method for a collection structure. In this oil separator, gas containing mist-like oil is discharged toward a collision wall covered with a collection body made of a woven fabric or a non-woven fabric. The gas that collides with the collision wall is bent in its traveling direction and flows. On the other hand, the mist-like oil contained in the gas is separated from the gas by being adsorbed by the collection body.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The above-mentioned gas contains dust such as sludge in addition to mist-like oil. When such gas collides with the collision wall, the dust contained in the gas accumulates on the surface of the collection body without being able to turn due to inertia. As a result, the collection body may become clogged.
[0005] Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide an oil separator having a collection structure that is difficult to become clogged.
Means for Solving the Problems
[0006] To solve the above problems, an oil separator is provided, comprising a collection structure for collecting mist-like oil from a gas containing mist-like oil, and a case having an internal space for housing the collection structure, wherein the collection structure comprises a main body that forms an upstream space to which the gas is supplied, a valve that forms a flow path connecting the upstream space and the external space of the main body and increases the opening of the flow path as the gas pressure in the upstream space increases, and a breathable collector positioned opposite the outlet of the flow path, and a downstream space through which the gas that has passed the collector flows is formed between the collection structure and the case. [Effects of the Invention]
[0007] According to the oil separator of the present invention, the collected material is less likely to become clogged. [Brief explanation of the drawing]
[0008] [Figure 1] This is a schematic diagram showing a closed-type crankcase ventilation system 1. [Figure 2] This is a perspective view of oil separator 2. [Figure 3] This is an exploded view of oil separator 2. [Figure 4] This is a top view of the oil separator 2. [Figure 5] This is a cross-sectional view of the oil separator 2. [Figure 6] Figure 5 is a cross-sectional view of BB. [Figure 7] Figure 5 is a cross-sectional view of CC. [Figure 8] Figure 5 is a cross-sectional view of the drive unit (DD). [Figure 9] Figure 5 is a cross-sectional view of the EE. [Figure 10] This is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas. [Figure 11] This is a cross-sectional view of the oil separator 2 showing the flow of the collected oil. [Figure 12]This is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas when valve 70 is closed. [Figure 13] This is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas when valve 70 is open. [Modes for carrying out the invention]
[0009] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are subject to various technically preferred limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.
[0010] ==Overview of Closed Crankcase Ventilation Systems== Figure 1 is a schematic diagram of a closed-type crankcase ventilation system (hereinafter referred to as ventilation system 1). Ventilation system 1 comprises an oil separator 2, a gas supply pipe 3, an oil passage 4, and a breather pipe 5. The oil separator 2 performs a process to separate mist-like oil from blow-by gas (an example of gas containing mist-like oil) discharged into the crankcase of the engine 6. The oil separator 2 is attached to the main body of the engine 6 via a bracket (not shown). The gas supply pipe 3 supplies blow-by gas discharged from the crankcase of the engine 6 to the oil separator 2. The oil passage 4 returns the oil separated by the oil separator 2 to the engine 6. The breather pipe 5 returns the blow-by gas, after oil removal, discharged from the oil separator 2 to the intake-side passage 7 of the engine 6. Specifically, the breather pipe 5 returns the blow-by gas, after oil removal, to the part of the intake-side passage 7 that connects the air filter 8 and the turbocharger 9. The blow-by gas, after the oil has been reduced and removed, is mixed with outside air from the air filter 8 and compressed by the turbocharger 9. The compressed blow-by gas is cooled by the charge air cooler 10 and supplied to the engine 6. The ventilation system 1 may also be an open-type crankcase ventilation system in which the breather pipe 5 is not connected to the intake side passage 7. In this case, the blow-by gas after the oil has been removed, discharged from the oil separator 2, is released into the atmosphere. Furthermore, the oil separator 2 may be fixed to a component other than the engine 6, such as the vehicle frame, via a bracket or the like, rather than to the engine 6 itself.
[0011] ==Oil Separator Structure== The oil separator 2 will be described with reference to Figures 2 to 13. The oil separator 2 comprises a case 20, a collection structure 50, a leaf spring 120 (an example of an assembled elastic body), a check valve holder 130, and a second check valve 150 (see Figures 2 and 3).
[0012] <Case> The case 20 is a member that constitutes the exterior of the oil separator 2. The case 20 has an internal space in which the repair structure 50, the leaf spring 120, and the check valve holder 130 are arranged. The case 20 has a lower case 21 (an example of the first case) and an upper case 22 (an example of the second case). In the following description, "up" and "down" shall mean "up" and "down" in FIGS. 2 and 3.
[0013] (Lower case) The lower case 21 is a frustum-shaped cylindrical member with an open upper end. The lower case 21 has an inflow port 23, an oil discharge port 24, an opening 25, a claw portion 26, and a cylindrical body 27 (see FIGS. 2, 3, and 5).
[0014] The inflow port 23 is a part for allowing blow-by gas to flow into the interior of the oil separator 2. The inflow port 23 according to the present embodiment is cylindrical. One inflow port 23 is provided on the outer peripheral side surface of the lower case 21 so as to protrude radially outward. The internal space of the inflow port 23 communicates with the internal space of the lower case 21. A gas supply pipe 3 is connected to the inflow port 23.
[0015] The oil discharge port 24 is a part for allowing the oil separated from the blow-by gas to flow out of the oil separator 2 to the outside. The oil discharge port 24 according to the present embodiment is cylindrical. One oil discharge port 24 is provided at the lower end of the lower case 21. The internal space of the oil discharge port 24 communicates with the internal space of the lower case 21. An oil flow path 4 is connected to the oil discharge port 24.
[0016] The opening 25 is an opening for inserting a member arranged in the internal space of the case 20. The opening 25 is provided at the upper end of the lower case 21.
[0017] The claw portion 26 is the part that engages with the hook portion 30 (described later) to attach the upper case 22 to the lower case 21. The claw portion 26 is provided on the outer circumferential surface near the upper end of the lower case 21 so as to protrude radially outward. The position and number of claw portions 26 are not particularly limited as long as the upper case 22 can be attached to the lower case 21. In this embodiment, four claw portions 26 are provided, spaced apart in the circumferential direction.
[0018] The cylindrical body 27 is a part for attaching the oil separator 2 to the engine 6. The cylindrical body 27 is a cylindrical part that protrudes from the outer peripheral side of the lower case 21. The position and number of cylindrical bodies 27 are not particularly limited as long as the oil separator 2 can be attached to the engine 6. In this embodiment, a total of six cylindrical bodies 27 are provided: four on the outer peripheral surface near the upper end of the lower case 21 and two on the outer peripheral surface near the lower end.
[0019] A mounting hole 27a is provided at the tip of the cylindrical body 27. The mounting hole 27a is a part for attaching fastening members such as bolts. One mounting hole 27a is provided for each cylindrical body 27. A bracket (not shown) is attached to the mounting hole 27a via a bolt. The oil separator 2 is attached to the engine 6 via the bracket.
[0020] (Upper case) The upper case 22 is provided to close the opening 25 of the lower case 21. The upper case 22 has an outer cylinder 28, a discharge port 29, a hook portion 30, a flange portion 31, a stopper portion 33, a large diameter cylinder 34, a small diameter cylinder 35, a lid portion 36, an opening 37, a first connection portion 38a, a second connection portion 38b, and a PCV valve 40 (see Figures 2-5).
[0021] The outer cylinder 28 is a member that closes the opening 25. The outer cylinder 28 is a substantially cylindrical member with a closed upper end and an open lower end. The upper case 22 is attached to the lower case 21 such that the opening 28a at the lower end of the outer cylinder 28 faces the opening 25 of the lower case 21.
[0022] The flange portion 31 is the part for which the hook portion 30 is positioned. The flange portion 31 is an annular portion that extends radially outward from the side surface of the outer cylinder 28.
[0023] The hook portion 30 is the part that engages with the claw portion 26 of the lower case 21 to attach the upper case 22 to the lower case 21. The hook portion 30 is provided extending downward from the outer edge of the flange portion 31. The position and number of the hook portions 30 are not particularly limited as long as the upper case 22 can be attached to the lower case 21. In this embodiment, four hook portions 30 are provided spaced apart in the circumferential direction.
[0024] The stopper portion 33 is a part that restricts the movement of the O-ring 32. The stopper portion 33 is an annular portion that contacts the lower surface of the flange portion 31 and protrudes radially outward from the outer side surface of the cylindrical portion 28. The O-ring 32 is positioned on the lower surface of the stopper portion 33 to seal the space between the lower case 21 and the upper case 22.
[0025] The large-diameter cylindrical body 34 is a part that partitions the inside of the upper case 22. The large-diameter cylindrical body 34 is a cylindrical part with a smaller diameter than the outer cylinder 28. The large-diameter cylindrical body 34 is positioned inside the outer cylinder 28.
[0026] The small-diameter cylinder 35, together with the large-diameter cylinder 34, is a part that partitions the inside of the upper case 22. The small-diameter cylinder 35 is a cylindrical part with a smaller diameter than the large-diameter cylinder 34. The small-diameter cylinder 35 is positioned inside the large-diameter cylinder 34.
[0027] The lid portion 36 is the part that closes the lower opening of the small-diameter cylindrical body 35. The lid portion 36 is a circular plate. The lid portion 36 is provided at the lower end of the small-diameter cylindrical body 35. Together with the small-diameter cylindrical body 35, the lid portion 36 partitions the space inside the upper case 22.
[0028] The opening 37 is a portion for allowing blow-by gas to flow into the inside of the small-diameter cylindrical body 35. The opening 37 is the opening at the upper end of the small-diameter cylindrical body 35.
[0029] The first connecting portion 38a is a part that joins the large-diameter cylindrical body 34 and the cylindrical body 28 to prevent the passage of blow-by gas. The first connecting portion 38a is an annular plate material. In this embodiment, the first connecting portion 38a is provided from the upper end of the large-diameter cylindrical body 34 toward the inner circumferential surface of the cylindrical body 28.
[0030] The second connecting portion 38b is the part that joins the small-diameter cylinder 35 and the large-diameter cylinder 34. The second connecting portion 38b is a rectangular plate material. The position and number of the second connecting portions 38b are not particularly limited as long as they can join the small-diameter cylinder 35 and the large-diameter cylinder 34. In this embodiment, the second connecting portions 38b are provided from the lower end of the large-diameter cylinder 34 toward the outer circumferential surface of the small-diameter cylinder 35, and three are provided spaced apart in the circumferential direction.
[0031] The discharge port 29 is a part that allows blow-by gas, after oil removal, to flow out from the inside of the oil separator 2 to the outside. In this embodiment, the discharge port 29 is cylindrical. The discharge port 29 is provided as a single port that extends radially outward from the side of the small-diameter cylindrical body 35, passing through the side of the large-diameter cylindrical body 34 and the side of the outer cylinder 28, and extending to the outside of the outer cylinder 28. The internal space of the discharge port 29 is in communication with the internal space of the small-diameter cylindrical body 35. A breather pipe 5 is connected to the discharge port 29.
[0032] The PCV valve 40 is a component for opening and closing the opening 37 of the small-diameter cylindrical body 35. The PCV valve 40 comprises a diaphragm valve 41 and a spring 42 (see Figure 5).
[0033] The diaphragm valve 41 opens and closes the opening 37. The diaphragm valve 41 is a disc-shaped component. The diaphragm valve 41 is housed in the internal space of the upper case 22 so as to face the opening 37. The diaphragm valve 41 has a valve portion 41a and a membrane portion 41b.
[0034] The valve portion 41a is the part that opens and closes the opening 37. In this embodiment, the shape of the valve portion 41a is disc-shaped. The valve portion 41a is provided above the opening 37.
[0035] The membrane portion 41b is the part that connects the valve portion 41a and the outer cylinder 28. The membrane portion 41b is an annular portion that is elastically deformable. The membrane portion 41b connects the radially outer end of the valve portion 41a to the inner circumferential surface of the outer cylinder 28.
[0036] The spring 42 supports the valve portion 41a so that it can move up and down. The spring 42 is a coil spring. The spring 42 is located inside the small diameter cylindrical body 35 and below the valve portion 41a, sandwiched between the valve portion 41a and the cover portion 36, and biases the valve portion 41a upward.
[0037] The inside of the upper case 22 is partitioned by a small-diameter cylindrical body 35 and a lid 36. The space between the lower side of the small-diameter cylindrical body 35 and the lid 36 and the outer cylinder 28 corresponds to the upper upstream space S4, and the internal space between the inside of the small-diameter cylindrical body 35 and the upper side of the lid 36 corresponds to the upper downstream space S5.
[0038] When the spring 42 compresses, the membrane portion 41b elastically deforms and stretches, and only the valve portion 41a moves downward, causing the valve portion 41a to come into contact with the upper end of the small-diameter cylindrical body 35. As a result, the opening 37 is closed, and the upper upstream space S4 and the upper downstream space S5 are separated from each other. On the other hand, when the spring 42 stretches, the membrane portion 41b elastically deforms and compresses, causing the valve portion 41a to move upward, separating the valve portion 41a from the upper end of the small-diameter cylindrical body 35. As a result, the opening 37 opens, and the upper upstream space S4 and the upper downstream space S5 are in communication with each other.
[0039] <Collection structure> The collection structure 50 is a structure for separating mist-like oil from blow-by gas. The repair structure 50 is housed in the internal space of the lower case 21. The collection structure 50 includes a main body 60, a valve 70, a collection body 80, a holding member 90, a retaining member 110, and a first check valve 140 (see Figures 3 and 5).
[0040] (Main body) The main body portion 60 is the part that constitutes the cylindrical frame that forms the basic part of the collection structure 50. The main body portion 60 has an annular disc portion 61, a small diameter cylindrical portion 62, a large diameter cylindrical portion 63, a flange portion 64, a square cylindrical portion 66, and a cylindrical portion 69 (see Figures 3 and 10). Note that in Figure 10, the main body portion 60 has been rotated 45 degrees in the circumferential direction relative to the cross-sectional view in Figure 5 for explanatory purposes, so the second connection portion 38b of the upper case 22 is not shown.
[0041] The annular disc portion 61 is the part that connects the small-diameter cylindrical portion 62 and the large-diameter cylindrical portion 63. The annular disc portion 61 is an annular and plate-shaped part with a through hole formed in its center.
[0042] The small-diameter cylindrical portion 62 is a part that constitutes the upper part of the main body portion 60. The small-diameter cylindrical portion 62 is a cylindrical part. The diameter of the small-diameter cylindrical portion 62 is equal to the inner diameter of the annular disc portion 61. The small-diameter cylindrical portion 62 protrudes upward along the radially inner edge of the annular disc portion 61. The ends of the small-diameter cylindrical portion 62 are open at both the top and bottom.
[0043] The large-diameter cylindrical portion 63 is the central part of the main body portion 60. The large-diameter cylindrical portion 63 is a cylindrical part. The diameter of the large-diameter cylindrical portion 63 is larger than the diameter of the small-diameter cylindrical portion 62. The large-diameter cylindrical portion 63 protrudes downward from the lower surface of the annular disc portion 61.
[0044] The flange portion 64 is a part that constitutes the lower part of the main body portion 60. The flange portion 64 is an annular portion. The outer diameter of the flange portion 64 is slightly smaller than the inner diameter of the lower case 21. The flange portion 64 is provided at the lower end of the large diameter cylindrical portion 63. In addition, a groove 64a is formed in the circumferential direction of the flange portion 64, opening radially outward. An O-ring 65 is placed in the groove 64a to seal the space between the flange portion 64 and the lower case 21.
[0045] The rectangular tube portion 66 is a part that forms a rectangular tube-shaped internal space. The rectangular tube portion 66 is a rectangular tube-shaped part with a substantially square cross-section. The rectangular tube portion 66 is provided between the lower surface of the annular disc portion 61 and the upper surface of the flange portion 64. The rectangular tube portion 66 is provided from the side surface of the large-diameter tube portion 63, through the radial center, to the side surface of the large-diameter tube portion 63 on the radially opposite side. The rectangular tube portion 66 opens at the side surface of the large-diameter tube portion 63 and forms an internal space S6 that communicates with the external space of the main body portion 60. The rectangular tube portion 66 has a central wall portion 66a, a through hole 67, and a hole 68 (see Figures 3, 5, and 9).
[0046] The central wall portion 66a is the part that partitions the internal space of the rectangular tube portion 66. When viewed from above, the central wall portion 66a bulges radially in the center, with the rest being plate-like. The central wall portion 66a is located at the radial center inside the rectangular tube portion 66. This divides the internal space S6 into two.
[0047] The through-hole 67 is a hole into which the first check valve 140 is installed. The through-hole 67 is a hole that penetrates vertically through the central part of the central wall portion 66a where the center bulges radially.
[0048] The hole 68 is a hole that connects the internal space S6 of the rectangular tube portion 66 to the external space. The hole 68 is a hole that penetrates vertically through the lower surface of the rectangular tube portion 66. The hole 68 is provided near the central wall portion 66a.
[0049] The cylindrical portion 69 is the part that comes into contact with the check valve structure 130. The cylindrical portion 69 is a cylindrical part. The cylindrical portion 69 extends downward from the lower surface of the rectangular tube portion 66 (see Figures 5 and 10).
[0050] The main body 60 is fitted into the lower case 21 from above, thereby dividing the internal space of the lower case 21 into the space on the inflow port 23 side and the space on the opening 25 side. As a result, an upstream space S1 and a downstream space S3 are formed. The upstream space S1 is the space on the inflow port 23 side, which includes the internal space of the main body 60, within the internal space of the lower case 21 divided by the main body 60. The downstream space S3 is the space between the collection structure 50 and the lower case 21 in the space on the opening 25 side, within the internal space of the lower case 21 divided by the main body 60.
[0051] Here, the upstream space S1 and the downstream space S3 will be described. The upstream space S1 communicates with the inflow port 23. The downstream space S3 communicates with the upper upstream space S4 of the upper case 22. The downstream space S3 also communicates with the internal space S6 of the rectangular tube portion 66 provided on the radially outer side surface of the collection structure 50 (see Figure 10).
[0052] (First check valve) The first check valve 140 is a valve that opens and closes the hole 68 in the main body 60 (specifically the rectangular tube portion 66). The first check valve 140 has a valve body 141, a shaft portion 142, and a stopper portion 143 (see Figures 5, 9, and 10).
[0053] The valve body 141 is the part that opens and closes the hole 68. The valve body 141 is a circular plate member. The position and number of valve bodies 141 are not particularly limited as long as they can open and close the hole 68. In this embodiment, one valve body 141 is provided on the lower surface of the rectangular tube portion 66 so as to cover the hole 68.
[0054] The shaft portion 142 is a part that restricts the direction of movement of the valve body 141. The shaft portion 142 is a rod-shaped part. The shaft portion 142 is provided so as to pass through the center of the valve body 141. The shaft portion 142 is inserted into the through hole 67 of the rectangular tube portion 66. This allows the shaft portion 142 to move up and down along the through hole 67 together with the valve body 141. As the shaft portion 142 moves up and down, the valve body 141 moves up and down, opening and closing the hole 68.
[0055] The stopper portion 143 is a part that restricts the vertical movement of the valve body 141 and the shaft portion 142. The stopper portion 143 is a part of the shaft portion 142 that bulges radially. The stopper portion 143 is provided on the shaft portion 142 at a specific distance above the upper surface of the valve body 141. Here, the specific distance is the sum of the vertical length of the through hole 67 and the amount by which the valve body 141 moves vertically. The diameter of the stopper portion 143 is larger than the diameter of the through hole 67. Therefore, when the shaft portion 142 moves downward, the stopper portion 143 comes into contact with the edge of the through hole 67, restricting the downward movement of the valve body 141.
[0056] The pressure of the internal space S6 of the rectangular tube portion 66 acts on the upper surface of the valve body 141, and the pressure of the internal space of the cylindrical portion 69 (i.e., the pressure of the upstream space S1) acts on the lower surface of the valve body 141. If the pressure of the internal space S6 is greater than the pressure of the upstream space S1, the valve body 141 moves downward and opens the hole 68. On the other hand, if the flow rate of blow-by gas flowing into the upstream space S1 increases and the pressure of the blow-by gas in the upstream space S1 acting on the lower surface of the valve body 141 increases, the valve body 141 moves upward and closes the hole 68.
[0057] (valve) Valve 70 is a valve that regulates the flow rate of blow-by gas flowing from the upstream space S1. Valve 70 is positioned above the upper end opening of the small-diameter cylindrical portion 62 of the main body 60, facing each other vertically. Valve 70 closes the upper end opening of the small-diameter cylindrical portion 62 by moving downward. Valve 70 opens the upper end opening of the small-diameter cylindrical portion 62 by moving upward, creating a gap between valve 70 and the upper end opening of the small-diameter cylindrical portion 62. Valve 70 has a valve body 71, a cylindrical portion 73, a spring 74, a hole 75, and a stopper portion 76 (see Figures 5, 7, 12, and 13). Note that in Figures 12 and 13, for explanatory purposes, the main body 60 is rotated 45 degrees circumferentially and valve 70 is rotated 90 degrees circumferentially relative to the cross-sectional view in Figure 5.
[0058] The valve body 71 is a valve element that opens and closes the upper end opening of the small-diameter cylindrical portion 62. The valve body 71 is a disc-shaped member. The valve body 71 is positioned above the upper end opening of the small-diameter cylindrical portion 62 of the main body 60. The upper end opening of the small-diameter cylindrical portion 62 opens and closes as the valve body 71 moves up and down. The valve body 71 has a valve elastic body 72.
[0059] The valve elastic body 72 mitigates the impact when the valve body 71 contacts the upper end opening of the small-diameter cylindrical portion 62. The valve elastic body 72 is an elastic annular member. The valve elastic body 72 is provided along the outer peripheral edge of the lower surface of the valve body 71. When the valve body 71 moves downward, the valve elastic body 72 contacts the upper end opening of the small-diameter cylindrical portion 62. When the valve body 71 moves upward, the valve elastic body 72 moves upward away from the upper end opening of the small-diameter cylindrical portion 62, forming an annular gap between the valve elastic body 72 and the upper end of the small-diameter cylindrical portion 62. When blow-by gas flows into the upstream space S1, this gap becomes the blow-by gas flow path C1. The size of this gap changes depending on the vertical position of the valve body 71. In other words, the flow path C1 is a flow path whose opening degree changes.
[0060] The cylindrical portion 73 lowers the center of gravity of the valve 70, making it less likely for the valve 70 to tilt relative to the main body 60 when an uneven force is applied to the valve 70. The cylindrical portion 73 is a cylindrical part. The cylindrical portion 73 is provided so as to protrude downward from the lower surface of the valve body 71. In this embodiment, the cylindrical portion 73 is located in the upstream space S1. Note that the cylindrical portion 73 may not be provided on the valve body 71.
[0061] The hole 75 is a part that allows blow-by gas from the upstream space S1 to flow out regardless of the open or closed state of the valve 70. The hole 75 is a hole that connects the space outside the valve body 71 with the internal space of the cylindrical portion 73 (see Figures 12 and 13). The hole 75 is provided from the side of the valve body 71 to the internal space of the cylindrical portion 73. When blow-by gas flows into the internal space of the cylindrical portion 73, the hole 75 becomes the blow-by gas flow path C2. The size of the hole 75 does not change depending on the flow rate of blow-by gas flowing into the internal space of the cylindrical portion 73. That is, the flow path C2 is a flow path with a constant opening. However, the present invention is not limited to this, and the valve 70 may be configured without the hole 75 (flow path C2).
[0062] The spring 74 supports the valve body 71 in a state where it can move up and down. The spring 74 is a coil spring. The spring 74 is positioned on the upper surface of the valve body 71. Specifically, the spring 74 is sandwiched between the upper surface of the valve body 71 and the lower surface of the disc portion 111 of the retaining member 110, which will be described later, and biases the valve body 71 downward.
[0063] The stopper portion 76 contacts the lower surface of the cylindrical portion 114 of the retaining member 110, which will be described later, and restricts the amount of vertical movement of the valve body 71. The stopper portion 76 in this embodiment is cross-shaped (see Figure 7). The stopper portion 76 protrudes upward from the upper surface of the valve body 71. When the valve body 71 moves upward, the stopper portion 76 contacts the lower surface of the cylindrical portion 114, restricting the valve body 71 from moving any further upward.
[0064] Here, we will describe the flow paths C1 and C2. The inlet of flow path C1 is the internal space (upstream space S1) of the small-diameter cylindrical section 62. The outlet of flow path C1 is the outside of the small-diameter cylindrical section 62 and the outside of the valve 70. The inlet of flow path C2 is the internal space (upstream space S1) of the cylindrical section 73. The outlet of flow path C2 is the outside of the valve 70.
[0065] (collector) The collector 80 is a breathable component that separates mist-like oil from blow-by gas. The collector 80 is made of, for example, nonwoven fabric. The collector 80 is radially opposite the outlets of flow path C1 and flow path C2 (see Figures 3, 5, 8, and 10). The space between the collector 80 and the outside of the valve 70 and the outside of the small-diameter cylindrical portion 62 in the space on the opening 25 side of the internal space of the lower case 21 partitioned by the main body 60 is defined as the downstream space S2.
[0066] (Retaining member) The holding member 90 is a member for holding the collecting body 80. In this embodiment, the holding member 90 holds the collecting body 80 by sandwiching it from the radial outside and inside. Specifically, the holding member 90 has a rod 91 (an example of a holding part), a column member 92 (an example of a holding part), an inner holding member 93, and a lower holding member 100 (see Figures 3, 5, 7, 8, and 10).
[0067] The rod members 91 are members that support the collecting body 80 from the radial outside. The number of rod members 91 is not particularly limited as long as they serve to support the collecting body 80 from the radial outside. In this embodiment, four examples are shown (see Figure 8). The rod members 91 are provided at circumferential intervals on the upper surface of the annular disc portion 61 of the main body portion 60. The rod members 91 extend upward from the upper surface of the annular disc portion 61 (see Figure 3).
[0068] The column members 92 are members that support the collecting body 80 from the radial outside. The column members 92 are also members to which the retaining members 110 are attached. The column members 92 are provided on the upper surface of the annular disc portion 61 of the main body portion 60 at circumferential intervals, and are provided between the two rod members 91 in the circumferential direction. In other words, the column members 92 and rod members 91 are provided alternately in the circumferential direction along the outer circumference of the collecting body 80. The column members 92 extend upward from the upper surface of the annular disc portion 61 (see Figure 3). The number of column members 92 is not particularly limited, as long as they support the collecting body 80 from the radial outside and to which the retaining members 110 are attached. In this embodiment, four examples are shown (see Figure 8).
[0069] The column member 92 has a projection 94. The projection 94 is the part to which the retaining member 110 is attached. The projection 94 is a part that protrudes from the upper surface of the column member 92. The projection 94 is provided on the upper surface of two of the four column members 92 that are radially opposite to each other (see Figures 3 and 7).
[0070] The inner holding member 93 is a member that supports the collecting body 80 from the inside in the radial direction. The inner holding member 93 is a rod-shaped member. The inner holding member 93 is provided on the upper surface of the annular disc portion 61 of the main body portion 60 at circumferential intervals and is positioned so as not to face the rod member 91 and the column member 92 in the radial direction. The inner holding member 93 extends upward from the upper surface of the annular disc portion 61 (see Figure 3). The number of inner holding members 93 is not particularly limited as long as they function to support the collecting body 80 from the inside in the radial direction. In this embodiment, an example of eight members is shown (see Figure 8).
[0071] The lower support member 100 is a member that supports the collection body 80 from below. The lower support member 100 is a rod-shaped member. The lower support member 100 is provided on the upper surface of the annular disc portion 61 of the main body portion 60 at circumferential intervals. The number of lower support members 100 is not particularly limited as long as they serve to support the collection body 80 from below. In this embodiment, an example of 16 members is shown (see Figures 3 and 8). The outer diameter end of the lower support member 100 is joined to the rod member 91 or column member 92, and the inner diameter end is joined to the inner holding member 93.
[0072] The rod 91, column member 92, and inner holding member 93 hold the collecting body 80 by sandwiching it radially. As described above, the rod 91 and column member 92 support the collecting body 80 from the radial outside. The inner holding member 93 supports the collecting body 80 from the radial inside. As a result, the collecting body 80 is arranged to be annular and surround the valve 70 from the outer circumference with a gap. The holding member 90 may be composed of one or two of the rod 91, column member 92, and inner holding member 93, as long as they can support the collecting body 80. For example, the holding member 90 may consist only of the rod 91 provided on the outer circumference of the collecting body 80. Furthermore, the number and shape of the rod 91, column member 92, and inner holding member 93 are not limited to those described above and can be freely changed.
[0073] (Pressing member) The retaining member 110 is a member that presses the spring 74 from above. However, in this embodiment, the retaining member 110 also supports the collector 80 from above. The retaining member 110 has a disc portion 111, a columnar surface portion 112, a flange portion 113, a cylindrical portion 114, and a projection portion 116 (see Figures 3, 5, and 7).
[0074] The disc portion 111 is the part that presses down on the spring 74 from above. The disc portion 111 is a circular plate member with a smaller outer diameter than the annular disc portion 61 of the main body portion 60 (see Figure 5). The lower surface of the disc portion 111 presses down on the spring 74 from above.
[0075] The cylindrical portion 114 is the part that restricts the radial movement of the spring 74. The cylindrical portion 114 is a cylindrical part with an open lower end (see Figure 5). The cylindrical portion 114 is provided on the lower surface of the disc portion 111. The spring 74 is arranged on the outer circumference of the cylindrical portion 114. Therefore, the radial movement of the spring 74 is restricted. In addition, when the valve 70 moves upward, the stopper portion 76 comes into contact with the lower end of the cylindrical portion 114. This limits the amount of upward movement of the valve 70.
[0076] The projection 116 is a part that restricts the radial movement of the leaf spring 120. The projection 116 is a part that protrudes upward from the upper surface of the disc portion 111. The projections 116 are provided at circumferential intervals on the upper surface of the disc portion 111. The number of projections 116 is not particularly limited as long as they have the function of restricting the radial movement of the leaf spring 120. In this embodiment, an example of four projections is shown (see Figure 3).
[0077] The columnar surface portion 112 is the part that joins the disc portion 111 and the flange portion 113 in the vertical direction. The columnar surface portion 112 is a plate-shaped part. The columnar surface portion 112 is provided at circumferential intervals on the outer edge of the disc portion 111. The columnar surface portion 112 extends downward along the outer edge of the disc portion 111 to the height of the upper surface of the collecting body 80. The number of columnar surface portions 112 is not particularly limited as long as they serve to join the disc portion 111 and the flange portion 113 in the vertical direction. In this embodiment, eight examples are shown (see Figure 7).
[0078] The flange portion 113 is a member that supports the collecting body 80 from above. The flange portion 113 is a plate-shaped member. The number of flange portions 113 is not particularly limited as long as they serve to support the collecting body 80 from above. The flange portion 113 is provided radially outward from the lower end of the columnar surface portion 112. For this reason, this embodiment shows an example with eight flange portions 113 (see Figure 7). Since the flange portion 113 is provided from the lower end of the columnar surface portion 112, the lower surface of the flange portion 113 contacts the upper surface of the collecting body 80 and supports the collecting body 80 from above. The flange portion 113 holds the collecting body 80 by sandwiching it vertically together with the lower holding member 100. The flange portion 113 has a groove portion 115.
[0079] The groove 115 is the part that fits with the projection 94 of the column member 92. The groove 115 is a groove provided in each of the two radially opposing flange portions 113. The groove 115 is provided so as to open radially outward in the flange portion 113 and penetrate the flange portion 113 vertically. The groove 115 fits with the projection 94. As a result, the retaining member 110 is assembled to the main body portion 60 via the projection 94 and the column member 92.
[0080] <Leaf spring> The leaf spring 120 is a component that generates a repulsive force proportional to the amount of compression. The leaf spring 120 is a metal, annular component formed in a wave-like shape on its upper and lower sides. Therefore, when the leaf spring 120 is compressed vertically, it generates a repulsive force. One leaf spring 120 is positioned on the upper surface of the disc portion 111 and on the inner diameter side of the multiple protrusions 116. The leaf spring 120 is sandwiched between the upper surface of the disc portion 111 and the lower surface of the lid portion 36 and compressed vertically (see Figures 3 and 5). As a result, the leaf spring 120 generates a repulsive force, which acts a downward force on the collection structure 50 and the lower case 21 into which the collection structure 50 is fitted, through the disc portion 111. The repulsive force generated by the leaf spring 120 also acts an upward force on the upper case 22 through the lid portion 36, the small diameter cylinder 35, and the discharge port 29.
[0081] The leaf spring 120 acts a downward force on the lower case 21 and an upward force on the upper case 22. Here, the upper case 22 is assembled to the lower case 21 by fitting the hook portion 30 onto the claw portion 26 of the lower case 21, but due to variations in the dimensions of the hook portion 30 and the claw portion 26, looseness may occur in the fitting portion. In contrast, according to this embodiment, the leaf spring 120 acts a downward force on the lower case 21 and an upward force on the upper case 22 (that is, a repulsive force acts in the direction that separates the two cases vertically), so the upper case 22 is assembled to the lower case 21 without any looseness.
[0082] <Check valve holder> The check valve holder 130 is a component that prevents oil separated from blow-by gas from flowing from the space on the oil discharge port 24 side into the upstream space S1. The check valve holder 130 is provided in the internal space of the lower case 21 below the cylindrical portion 69 and near the upper end of the oil discharge port 24. The check valve holder 130 has a stepped cylindrical portion 131, a flange portion 132, a column portion 133, and a disc portion 134. (See Figures 3, 5, 10, and 11).
[0083] The stepped cylindrical section 131 is a part that divides the internal space of the lower case 21 into the upstream space S1 and the space on the oil discharge port 24 side. The stepped cylindrical section 131 is a member formed by arranging two cylindrical members of different diameters coaxially and continuously vertically, and joining the ends of the upper and lower cylindrical members with an annular plate. In the stepped cylindrical section 131, the diameter of the lower cylindrical member is smaller than the diameter of the upper cylindrical member. The upper and lower ends of the stepped cylindrical section 131 are open (see Figure 11). An O-ring 135 is placed on the outer circumference of the lower cylindrical member of the stepped cylindrical section 131 to seal the space between the stepped cylindrical section 131 and the lower case 21.
[0084] The flange portion 132 is the part that determines the position of the check valve holder 130 in the internal space of the lower case 21. The flange portion 132 is a plate-shaped portion formed in an annular shape. The flange portion 132 is provided at the upper end of the stepped cylindrical portion 131 and extends outward (see Figure 11). When the check valve holder 130 is fitted into the lower case 21 from above, the flange portion 132 comes into contact with the lower case 21, thereby positioning the check valve holder 130 in the internal space of the lower case 21.
[0085] The disc portion 134 is the part that closes the opening at the lower end of the stepped cylindrical portion 131. The disc portion 134 is provided at the lower end of the stepped cylindrical portion 131. Together with the stepped cylindrical portion 131, the disc portion 134 divides the internal space of the lower case 21 into the upstream space S1 and the space on the oil discharge port 24 side. The disc portion 134 has holes 136 and 137 (see Figure 11).
[0086] Hole 136 is the location where the second check valve 150 is installed. Hole 136 is a hole that penetrates the disc portion 134 vertically. Hole 136 is located at the center of the disc portion 134 (see Figure 11).
[0087] Hole 137 is a part that allows oil separated from blow-by gas to flow from the upstream space S1 to the space on the oil discharge port 24 side. Hole 137 is a hole that penetrates the disc portion 134 vertically. Hole 137 is provided at a position off-center from the center of the disc portion 134. The number of holes 137 is not particularly limited as long as they serve to allow oil separated from blow-by gas to flow from the upstream space S1 to the space on the oil discharge port 24 side. In this embodiment, an example with four holes 137 is shown.
[0088] The columnar portion 133 is the part that connects the check valve holder 130 to the cylindrical portion 69 of the main body portion 60 within the lower case 21. The columnar portion 133 is a columnar part. The position and number of columnar portions 133 are not particularly limited as long as they have the function of connecting the check valve holder 130 to the cylindrical portion 69. In this embodiment, an example with four columnar portions 133 is shown. The columnar portions 133 extend upward from the disc portion 134 inside the stepped cylindrical portion 131. The columnar portions 133 are provided at intervals in the circumferential direction. The upper end of the columnar portion 133 is connected to the lower surface of the cylindrical portion 69 when the check valve holder 130 is positioned inside the lower case 21. As a result, the downward force due to the repulsive force of the leaf spring 120 is transmitted from the cylindrical portion 69 through the column portion 133 to the check valve holder 130, and the check valve holder 130 is pressed downward against the lower case 21 and fixed in place.
[0089] <Second check valve> The second check valve 150 is a valve that opens and closes the hole 137. The second check valve 150 has a valve body 151, a shaft portion 152, and a stopper portion 153 (see Figures 5, 9, and 10).
[0090] The valve body 151 is the part that opens and closes the hole 137 of the check valve holder 130. The valve body 151 is a circular plate member. The position and number of valve bodies 151 are not particularly limited as long as they can open and close the hole 137. In this embodiment, one valve body 151 is provided on the lower surface of the disc portion 134 so as to cover the hole 137.
[0091] The shaft portion 152 is the part that restricts the direction of movement of the valve body 151. The shaft portion 162 is a rod-shaped part. The shaft portion 152 is provided so as to pass through the center of the valve body 151. The shaft portion 152 is inserted into the hole 136 of the check valve holder 130. This allows the shaft portion 152 to move up and down along the hole 136 together with the valve body 151. As the shaft portion 152 moves up and down, the valve body 151 moves up and down, opening and closing the hole 137.
[0092] The stopper portion 153 is a part that restricts the vertical movement of the valve body 151 and the shaft portion 152. The stopper portion 153 is a part of the shaft portion 152 that bulges radially. The stopper portion 153 is provided on the shaft portion 152 at a specific distance above the upper surface of the valve body 151. Here, the specific distance is the sum of the vertical length of the hole 136 and the amount by which the valve body 151 moves vertically. The diameter of the stopper portion 153 is larger than the diameter of the hole 136. Therefore, when the shaft portion 152 moves downward, the stopper portion 153 comes into contact with the edge of the hole 136, restricting the downward movement of the valve body 151.
[0093] The pressure of the upstream space S1 acts on the upper surface of the valve body 151, and the pressure of the space on the oil discharge port 24 side acts on the lower surface of the valve body 151. If the pressure of the upstream space S1 is greater than or equal to the pressure of the space on the oil discharge port 24 side, the valve body 151 moves downward and opens the hole 137. On the other hand, if the pressure of the space on the oil discharge port 24 side is greater than the pressure of the upstream space S1, the valve body 151 moves upward and closes the hole 137.
[0094] ==Blow-by gas flow== Here, we will explain the flow of blow-by gas. The black arrows in Figures 10 to 13 indicate the flow of blow-by gas. The blow-by gas introduced from the engine 6 through the gas supply pipe 3 to the inlet port 23 flows into the upstream space S1 through the inside of the main body 60.
[0095] Here, the flow rate of blow-by gas flowing into the upstream space S1 changes depending on the operating state of the engine 6, etc. As shown in Figure 12, when the flow rate of blow-by gas flowing into the upstream space S1 is small, the valve 70 is closed because the pressure of the blow-by gas in the upstream space S1 is low. Specifically, because the pressure of the blow-by gas in the upstream space S1 is low, the spring force of the spring 74 causes the valve elastic body 72 to tightly seal the upper end opening of the small-diameter cylindrical portion 62, thus closing the upper end opening of the small-diameter cylindrical portion 62. In this case, the blow-by gas flows to the external space S2 only through the passage C2.
[0096] On the other hand, when the flow rate of blow-by gas flowing into the upstream space S1 increases and the pressure of the blow-by gas in the upstream space S1 exceeds a certain magnitude, the valve 70 opens and the flow path C1 is formed, as shown in Figure 13. Specifically, when the pressure of the blow-by gas in the upstream space S1 rises, the upward force acting on the valve body 71 due to the pressure of the blow-by gas in the upstream space S1 becomes greater than the downward force acting on the valve body 71 by the spring 74. Consequently, the valve body 71 moves upward, the valve elastic body 72 moves upward away from the upper end of the small-diameter cylindrical portion 62, and the upper end opening of the small-diameter cylindrical portion 62 opens. In this case, the blow-by gas flows to the external space S2 through both flow paths C1 and C2.
[0097] Furthermore, the higher the pressure of the blow-by gas in the upstream space S1, the greater the upward movement of the valve body 71, and the larger the size of the flow path C1, which is the gap between the valve elastic body 72 and the upper end of the small-diameter cylindrical portion 62. In other words, the opening degree of the blow-by gas flow path C1 increases as the pressure of the blow-by gas in the upstream space S1 increases.
[0098] As described above, the larger the flow rate of blow-by gas flowing into the upstream space S1, the larger the opening of valve 70 (i.e., the opening of passage C1). Therefore, when the flow rate of blow-by gas flowing into the upstream space S1 is large, the opening of valve 70 (i.e., the opening of passage C1) is large, and thus the flow rate of blow-by gas flowing through passage C1 is large. On the other hand, the smaller the flow rate of blow-by gas flowing into the upstream space S1, the smaller the opening of valve 70 (i.e., the opening of passage C1). Therefore, when the flow rate of blow-by gas flowing into the upstream space S1 is small, the opening of valve 70 (i.e., the opening of passage C1) is small, and thus the flow rate of blow-by gas flowing through passage C1 is small. In addition, because the cross-sectional area of passage C1 becomes smaller, the flow velocity of the blow-by gas flowing through passage C1 becomes faster.
[0099] When the valve closes, the valve body collides with the valve seat, generating a knocking sound. When the valve is closed from a wide-open position, the valve body collides forcefully with the valve seat, generating a loud knocking sound. However, because the valve 70 is provided with a passage C2, when blow-by gas flows in at the same flow rate, the opening of the valve 70 is smaller compared to a valve without passage C2, thereby reducing the magnitude of the knocking sound generated when the valve body 71 and the valve seat (the upper end opening of the small-diameter cylindrical section 62) collide.
[0100] When the valve is open, if the flow rate of blow-by gas flowing into the upstream space fluctuates, the force acting on the valve due to the pressure of the blow-by gas becomes uneven. At this time, the valve may tilt relative to the main body, causing turbulence in the flow of blow-by gas passing through the passage formed between the valve and the main body. When the flow of blow-by gas is turbulent, the flow velocity of the blow-by gas slows down, and the performance of the collector (i.e., the performance of collecting mist-like oil from the blow-by gas) deteriorates. However, since the cylindrical portion 73 acts as a weight to lower the center of gravity of the valve body 71, the valve 70 is less likely to tilt relative to the main body 60. As a result, even if the flow rate of blow-by gas flowing into the upstream space S1 fluctuates when the valve 70 is open, the flow of blow-by gas passing through the passage C1 is less likely to be turbulent. Therefore, the performance of the collector 80 is less likely to deteriorate.
[0101] Furthermore, when the valve is open, fluctuations in the flow rate of blow-by gas flowing into the upstream space cause fluctuations in the blow-by gas pressure in the upstream space, resulting in uneven force acting on the valve. However, since a portion of the blow-by gas flows through the passage C2 to the external space S2, the fluctuation in blow-by gas pressure in the upstream space S1 is smaller compared to when the valve 70 does not have a passage C2. As a result, the force acting on the valve 70 due to the blow-by gas pressure is less likely to be uneven. Consequently, the valve 70 becomes less likely to tilt relative to the main body 60, further reducing turbulence in the flow of blow-by gas passing through the passage C1.
[0102] As described above, when valve 70 is closed, blow-by gas does not remain in the upstream space S1 but flows through the passage C2 to the external space S2. Therefore, since blow-by gas is less likely to remain in the upstream space S1, the blow-by gas pressure in the upstream space S1 does not rise as easily as when passage C2 is not provided. In other words, the flow rate of blow-by gas required for the blow-by gas pressure in the upstream space S1 to exceed a certain level and open valve 70 increases, so the frequency of valve 70 being open decreases.
[0103] Next, Figure 11 will be used to explain the flow of blow-by gas after it has passed through passages C1 and C2. For illustrative purposes, Figure 11 shows the main body 60 and the check valve holder 130 rotated 15 degrees circumferentially compared to the cross-sectional view in Figure 5.
[0104] As shown in Figure 11, the blow-by gas flows through passages C1 and C2 to the external space S2 and collides with the collector 80 located opposite the outlets of passages C1 and C2. As the blow-by gas passes through the collector 80, the mist-like oil contained in the blow-by gas is separated by being collected by the collector 80. After the oil has been removed from the blow-by gas that has passed through the collector 80, the blow-by gas flows through the gap between the rod 91 and the column member 92 to the downstream space S3.
[0105] Blow-by gas contains not only mist-like oil but also debris such as sludge. In conventional collection structures, blow-by gas does not pass through the collection body, so it cannot blow away debris attached to the collection body. As a result, debris accumulates on the collection body. However, according to this embodiment, since blow-by gas passes through the collection body 80, the blow-by gas can blow away debris attached to the collection body 80. Furthermore, when the flow rate of blow-by gas flowing into the upstream space S1 is large, the flow velocity of the blow-by gas flowing through the flow path C1 increases. Therefore, debris attached to the collection body 80 is more easily blown away by the blow-by gas. Also, when the flow rate of blow-by gas flowing into the upstream space S1 is small, the opening of the valve 70 decreases, and the flow velocity of the blow-by gas flowing through the flow path C1 increases. Therefore, debris attached to the collection body 80 is blown away by the blow-by gas.
[0106] As shown in Figure 11, the blow-by gas after oil removal flows from the downstream space S3 to the upper upstream space S4. If the PCV valve 40 is closed, the blow-by gas after oil removal remains in the upper upstream space S4. On the other hand, if the PCV valve 40 is open, the blow-by gas after oil removal flows to the upper downstream space S5. Then, the blow-by gas after oil removal flows through the discharge port 29 to the breather pipe 5.
[0107] Since the upper downstream space S5 is connected to the engine 6 through the discharge port 29 and the breather pipe 5, when the intake pressure (negative pressure) of the engine 6 increases and the force pulling the valve portion 41a of the diaphragm valve 41 downward becomes greater than the elastic force of the spring 42, the opening of the PCV valve 40 decreases. Furthermore, when the intake pressure of the engine 6 increases even more, the valve portion 41a comes into contact with the upper end of the small diameter cylinder 35 and the PCV valve 40 closes completely. On the other hand, when the intake pressure of the engine 6 decreases and the elastic force of the spring 42 becomes greater than the force pulling the valve portion 41a downward, the opening of the PCV valve 40 increases.
[0108] As described above, if the intake pressure (negative pressure) of engine 6 is excessively high, the opening of the PCV valve 40 decreases, reducing the flow rate of blow-by gas flowing into the upper downstream space S5. On the other hand, if the pressure on the crankcase side of engine 6 is high, the opening of the PCV valve 40 increases, increasing the flow rate of blow-by gas flowing into the upper downstream space S5. As a result, the flow rate of blow-by gas is appropriately regulated by the PCV valve 40. In addition, the pressure inside the crankcase of engine 6 is also appropriately regulated.
[0109] Furthermore, blow-by gas contains water vapor. Therefore, water vapor also adheres to the collector 80. In low-temperature environments, the water vapor adhering to the collector 80 may freeze, preventing the blow-by gas from passing through the collector 80. On the other hand, in this embodiment, since the lower holding members 100 are provided at intervals in the circumferential direction, a gap is formed between the lower holding members 100 below the collector 80. This gap connects the external space S2 and the downstream space S3. Also, since the flange portions 113 are provided at intervals in the circumferential direction, a gap is formed between the flange portions 113 above the collector 80. This gap connects the external space S2 and the downstream space S3. Therefore, even if the water vapor adhering to the collector 80 freezes and prevents the blow-by gas from passing through the collector 80, the blow-by gas collides with the collector 80, changing its direction of flow vertically, and flows from the external space S2 to the downstream space S3 through the gaps formed above and below the collector 80. Furthermore, when the blow-by gas collides with the collector 80 and changes direction of flow vertically, the mist-like oil contained in the blow-by gas cannot keep up with the change in flow direction and is separated from the blow-by gas by colliding with the collector 80 and being collected.
[0110] ==Oil Flow== Next, Figure 11 will be used to explain the flow of mist-like oil separated from blow-by gas. The white arrows indicate the flow of oil droplets. The mist-like oil separated from blow-by gas by the collector 80 aggregates to form oil droplets. As shown in Figure 11, the oil droplets flow from the collector 80 to the downstream space S3 due to the flow of blow-by gas flowing radially outward and gravity. The oil droplets that have flowed into the downstream space S3 then flow further into the internal space S6 below.
[0111] The oil droplets flow through the internal space S6 to the hole 68. The hole 68 is opened and closed by the first check valve 140. As described above, if the pressure in the upstream space S1, which is on the lower side of the valve body 141, is higher than the pressure in the internal space S6, which is on the upper side of the valve body 141, the valve body 141 is pushed up and the hole 68 closes. Therefore, blow-by gas containing mist-like oil flowing into the upstream space S1 does not flow into the internal space S6. On the other hand, if the pressure in the internal space S6 is higher than or equal to the pressure in the upstream space S1, the valve body 141 is pushed down and the hole 68 opens. At this time, the oil droplets flow through the hole 68 to the upstream space S1. The oil droplets then flow downward along the inside of the cylindrical portion 69 and the column portion 133, and flow into the hole 137.
[0112] The hole 137 is opened and closed by the second check valve 150. As described above, if the pressure in the space on the oil discharge port 24 side, which is on the lower side of the valve body 151, is higher than the pressure in the upstream space S1, which is on the upper side of the valve body 151, the valve body 151 is pushed up and the hole 137 closes. This prevents droplet-like oil from flowing from the space on the oil discharge port 24 side through the hole 137 into the upstream space S1. On the other hand, if the pressure in the upstream space S1 is higher than or equal to the pressure in the space on the oil discharge port 24 side, the valve body 151 is pushed down and the hole 137 opens. At this time, droplet-like oil flows through the hole 137 into the space on the oil discharge port 24 side. Then, the droplet-like oil flows from the oil discharge port 24 through the oil passage 4 to the engine 6.
[0113] <Effects> In this embodiment, the oil separator 2 comprises a collection structure 50 for collecting mist-like oil from blow-by gas and a case 20 having an internal space for housing the collection structure 50. The collection structure 50 comprises a main body 60 that forms an upstream space S1 to which blow-by gas is supplied, a flow path C1 that connects the upstream space S1 and the external space S2 of the main body 60, and a valve 70 that increases the opening of the flow path C1 as the pressure of the blow-by gas in the upstream space S1 increases, and a breathable collector 80 that is positioned opposite the outlet of the flow path C1. A downstream space S3 is formed between the collection structure 50 and the case 20 through which the blow-by gas that has passed through the collector 80 flows.
[0114] With the configuration described above, blow-by gas flows from the upstream space S1 through the flow path C1 and collides with the collector 80 facing the outlet of the flow path C1. The mist-like oil contained in the blow-by gas is separated from the blow-by gas as it passes through the collector 80. The blow-by gas that has passed through the collector 80 flows into the downstream space S3. At this time, debris such as sludge contained in the blow-by gas may adhere to the collector 80. However, the debris adhering to the collector 80 is blown away by the blow-by gas that passes through the collector 80 and flows into the downstream space S3. Thus, with the configuration according to this embodiment, debris adhering to the collector 80 can be removed. Therefore, clogging of the collector 80 can be reduced.
[0115] Furthermore, if the size of the blow-by gas flow path is constant, when the blow-by gas flow rate is small, the flow velocity of the blow-by gas is slow, making it difficult to blow away debris attached to the collector. On the other hand, according to the configuration of this embodiment, when the pressure of the blow-by gas in the upstream space S1 is low, that is, when the flow rate of blow-by gas flowing into the upstream space S1 is small, the opening of the valve 70 (i.e., the opening of the flow path C1) becomes small, so that the flow velocity of the blow-by gas flowing out of the flow path C1 can be increased. As a result, even when the flow rate of blow-by gas flowing into the upstream space S1 is small, the blow-by gas passes through the collector 80 at a high flow velocity. As a result, even when the flow rate of blow-by gas flowing into the upstream space S1 is small, the blow-by gas can blow away debris attached to the collector 80, making the collector 80 less likely to become clogged.
[0116] Furthermore, because the collector 80 is positioned opposite the outlet of the flow path C1, the blow-by gas exiting the flow path C1 collides with the collector 80 while maintaining almost the same flow velocity without changing direction. As a result, the blow-by gas is more effectively able to blow away any debris attached to the collector 80.
[0117] Furthermore, in this embodiment, the oil separator 2 has an annular flow path C1 and an annular collection body 80, and the collection structure 50 further comprises a holding member 90 for holding the collection body 80.
[0118] With this configuration, since the flow path C1 is annular, the blow-by gas can flow in multiple directions. Also, since the collector 80 facing the outlet of the flow path C1 is also annular, the blow-by gas exiting the flow path C1 passes through the collector 80, and the collector 80 can reliably capture the mist-like oil contained in the blow-by gas. As a result, the efficiency of separating the mist-like oil from the blow-by gas by the collector 80 is improved.
[0119] Furthermore, since the holding member 90 holds the collector 80, the position of the collector 80 does not shift even if blow-by gas collides with it. Therefore, the collector 80 can separate mist-like oil from the blow-by gas.
[0120] Furthermore, the holding member 90 of the oil separator 2 according to this embodiment has a plurality of rod members 91 provided around the outer circumference of the collecting body 80 at intervals in the circumferential direction.
[0121] With this configuration, the blow-by gas that has passed through the collector 80 can flow to the downstream space S3 through the gaps between the multiple rod members 91. In other words, the rod members 91 can hold the collector 80 without obstructing the flow of blow-by gas.
[0122] Furthermore, the holding member 90 of the oil separator 2 according to this embodiment has a lower holding member 100 and a flange portion 113, which are provided at both axial ends of the collecting body 80 and have a plurality of holding portions provided at intervals in the circumferential direction on at least one side of the ends.
[0123] With this configuration, since the holding member 90 is not placed on the outer circumference of the collector 80, the blow-by gas that has passed through the collector 80 flows more easily into the downstream space S3.
[0124] Furthermore, the valve 70 of the oil separator 2 according to this embodiment further has a cylindrical portion 73 that protrudes so as to enter the upstream space S1.
[0125] In conventional oil separators, when the flow rate of blow-by gas fluctuates while the valve is open, the force acting on the valve due to the pressure of the blow-by gas becomes uneven, which can cause the valve to tilt relative to the main body. When the valve is tilted relative to the main body, the direction of the blow-by gas flow passing between the valve and the main body is disturbed, reducing the flow velocity of the blow-by gas. As a result, the force with which the blow-by gas strikes the collector weakens, which can reduce the performance of the collector (i.e., its ability to collect mist-like oil from the blow-by gas). In contrast, in this embodiment, the cylindrical portion 73 acts as a weight to lower the center of gravity of the valve body 71, so even if the force acting on the valve 70 is uneven, the valve 70 is less likely to tilt relative to the main body 60. As a result, even if the flow rate of blow-by gas flowing into the oil separator 2 fluctuates, the direction of the blow-by gas flow passing through the flow path C1 is less likely to be disturbed, and the flow velocity of the blow-by gas is less likely to decrease. Therefore, the performance of the collector 80 is less likely to decrease.
[0126] Furthermore, the oil separator 2 according to this embodiment is composed of a lower case 21 and an upper case 22 in which the case 20 engages with each other, and further includes a leaf spring 120 that generates a repulsive force between the lower case 21 and the upper case 22.
[0127] Generally, it is difficult to assemble case components that engage with each other accurately due to variations in dimensions. Therefore, processes such as welding or bonding are required to assemble the case components. In contrast, with the above configuration, even if there are variations in the dimensions of the lower case 21 and the upper case 22, the repulsive force generated by the leaf spring 120 can absorb the variations in dimensions. Therefore, the lower case 21 and the upper case 22 can be assembled accurately without using methods such as welding or bonding.
[0128] Furthermore, welding and bonding methods require jigs that match the shape of the case. Therefore, if the shape of the case changes due to a design change, a new jig that matches the shape of the case will be required. On the other hand, with the above configuration, a jig is not required when assembling the oil separator 2, thus reducing the cost required when changing the shape of the case 20.
[0129] Furthermore, as mentioned above, in conventional oil separators, if the flow rate of blow-by gas fluctuates while the valve is open, the valve may tilt relative to the main body, which can degrade the performance of the collector. However, in the oil separator 2 according to this embodiment, since a flow path C2 (hole 75) is provided in the valve body 71 of the valve 70, when the valve 70 is closed, the blow-by gas does not remain in the upstream space S1 but passes through the flow path C2. Therefore, even if the flow rate of blow-by gas flowing into the upstream space S1 increases, the pressure of the blow-by gas in the upstream space S1 is less likely to rise. As a result, the frequency of the valve 70 opening decreases, and the frequency of the valve 70 tilting relative to the main body 60 due to fluctuations in the flow rate of blow-by gas while the valve 70 is open decreases. In other words, the frequency of degradation of the performance of the collector 80 decreases.
[0130] Furthermore, in this embodiment, even if the flow rate of blow-by gas fluctuates when the valve 70 is open, a portion of the blow-by gas passes through the flow path C2, resulting in smaller fluctuations in the blow-by gas pressure in the upstream space S1 compared to the case where the valve body 71 does not have a flow path C2. Consequently, the force acting on the valve 70 when the flow rate of blow-by gas fluctuates becomes less uniform. As a result, even if the flow rate of blow-by gas fluctuates when the valve 70 is open, the valve 70 is less likely to tilt relative to the main body 60, thus preventing a decrease in the performance of the collector 80.
[0131] When the valve closes, the valve body collides with the valve seat, generating a knocking sound. As the flow rate of blow-by gas flowing into the upstream space increases, the valve opening becomes larger, and when the valve closes from that state, a loud knocking sound is generated. However, in the oil separator 2 according to this embodiment, since the valve body 71 is provided with a flow path C2, when the same flow rate of blow-by gas flows into the upstream space S1, the valve opening becomes smaller compared to a valve that is not provided with a flow path C2. Therefore, the knocking sound generated when the valve 70 closes is reduced.
[0132] <Variation> You may apply a combination of the changes described below.
[0133] (1) Variation 1 In the above embodiment, the collection structure 50 was equipped with a rod 91 and a column member 92 as holding members 90. However, the collection structure 50 may also be equipped with holding members instead of holding members 90, which are provided at both the upper and lower ends of the collection body 80 and have a plurality of holding parts spaced apart in the circumferential direction on at least one side of the ends.
[0134] An example of a retaining member is a modified lower retaining member 100 and flange portion 113. By providing a projection on the upper surface of the lower retaining member 100 that extends upward along the inner and outer circumferences of the collecting body 80, this projection prevents the collecting body 80 from moving radially. In other words, the lower retaining member 100 becomes a retaining member having a retaining portion. Similarly, by providing a projection on the lower surface of the flange portion 113 that extends downward along the inner and outer circumferences of the collecting body 80, this projection prevents the collecting body 80 from moving radially. In other words, the flange portion 113 becomes a retaining member having a retaining portion. Note that the projections provided as retaining portions on the lower retaining member 100 and flange portion 113 only need to be provided on at least one of the two.
[0135] Since both the lower holding member 100 and the flange portion 113 are provided with a gap between them in the circumferential direction, a gap is formed between adjacent lower holding members 100 in the circumferential direction, and a gap is also formed between adjacent flange portions 113 in the circumferential direction.
[0136] (2) Modification example 2 In the above embodiment, the oil separator 2 was equipped with a leaf spring 120 and consisted of a lower case 21 and an upper case 22 that engaged with each other. However, the oil separator 2 may be assembled by bonding or welding without being equipped with a leaf spring 120. [Explanation of Symbols]
[0137] 2… Oil separator 20... cases 21…Lower case (Case 1) 22…Upper case (second case) 50...Collection structure 60...Main body 70…valve 73...Cylindrical part 80…Collector 90…Retaining member 91...Bar material (holding part) 92...Column member (holding part) 120... Leaf spring (assembled elastic body) C1...flow channel S1…upstream space S2…External space S3…downstream space
Claims
1. A collection structure for collecting mist-like oil from a gas containing mist-like oil, A case having an internal space for housing the aforementioned collection structure, An oil separator comprising, The aforementioned collection structure is The main body forms an upstream space to which the aforementioned gas is supplied, A valve is provided that forms a flow path connecting the upstream space and the external space of the main body, and increases the opening degree of the flow path as the gas pressure in the upstream space increases. A collection body having air permeability is positioned opposite the outlet of the aforementioned flow path, Equipped with, A downstream space is formed between the collection structure and the case through which the gas that has passed through the collection body flows. The flow channel and the collecting body are annular, The collection structure further comprises a holding member for holding the collection body, The retaining member is a second retaining member provided at both ends in the axial direction of the collecting body, and having a plurality of retaining portions provided at intervals in the circumferential direction on at least one side of the ends. The radially outer side surface of the collecting body faces the downstream space, Oil separator.
2. The oil separator according to claim 1, wherein the holding member is a first holding member having a plurality of holding portions provided circumferentially at intervals around the outer circumference of the collecting body.
3. The oil separator according to claim 1, wherein the valve further has a cylindrical portion that protrudes so as to enter the upstream space.
4. The aforementioned case is composed of a first case and a second case that engage with each other. The oil separator according to any one of claims 1 to 3, further comprising an assembled elastic body that generates a repulsive force between the first case and the second case.