JP2024014013A - oil separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator capable of suppressing the magnitude of sound generated when a variable valve operates.

SOLUTION: An oil separator 2 includes a trapping structure 50 for trapping mist-like oil from blow-by gas, and a case 20 having an internal space for storing the trapping structure 50, the trapping structure 50 including a body part 60 forming an upstream space S1 into which the blow-by gas is supplied, and a valve 70 for forming a first flow path C1 to communicate the upstream space S1 with an external space S2 of the body part when the pressure of the blow-by gas in the upstream space S1 exceeds a predetermined value, while making the opening of the first flow path C1 larger as the pressure of the blow-by gas in the upstream space S1 is higher, the valve 70 having a second flow path C2 having a constant opening for communicating the upstream space S1 with the external space S2, the trapping structure 50 further including a trapping body 80 for trapping mist-like oil from the blow-by gas passing through the first flow path C1 and the second flow path C2.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an oil separator.

The oil separator separates oil mist from gas containing oil mist, such as engine blow-by gas. For example, Patent Document 1 discloses an oil separator having a variable valve. The variable valve includes a valve body that closes an opening of a flow path through which gas containing mist oil flows, and a spring that presses the valve body against the opening of the flow path that serves as a valve seat. The variable valve changes the size of the gas flow path containing mist-like oil in the variable valve by changing the distance of the valve body to the valve seat. By changing the size of the flow path, the flow velocity of the gas containing mist-like oil passing through the variable valve changes. When the flow rate of gas containing mist oil flowing into the oil separator is low, the pressure acting on the valve body due to the gas containing mist oil is low, so the distance that the valve body is away from the opening of the flow path is short, and the flow The road size is small. On the other hand, when the flow rate of gas containing mist-like oil flowing into the oil separator is high, the pressure acting on the valve body due to the gas containing mist-like oil is high, so the distance of the valve body from the opening of the flow path is long. , the size of the flow path is large. Therefore, when the flow rate of gas containing mist oil flowing into the oil separator changes, the position of the valve body relative to the valve seat changes (that is, the valve body moves relative to the valve seat).

Patent No. 4991850

When the valve body moves relative to the valve seat, pulsations occur in the gas passing through the variable valve. When the frequency of the pulsations generated in the gas matches the resonant frequency of the piping through which the gas flows, the piping resonates and generates loud noise.

Moreover, when the flow rate of gas becomes below a certain level, the valve body comes into contact with the valve seat and becomes closed. At this time, since the valve body collides with the valve seat, a tapping sound is generated from the collision part.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oil separator that can suppress the volume of noise generated when a variable valve operates.

In order to solve the above problems, an oil separator is provided that includes a collection structure that collects the oil mist from the gas containing the oil mist, and a case that has an internal space that accommodates the collection structure. The collection structure includes a main body forming an upstream space to which the gas is supplied, and when the pressure of the gas in the upstream space exceeds a predetermined value, the collection structure a valve that forms a first flow path communicating with the upstream space, and increases the opening degree of the first flow path as the pressure of the gas in the upstream space increases; and a second flow path with a constant opening that communicates with the external space, and the collection structure collects the mist-like oil from the gas that has passed through the first and second flow paths. An oil separator is provided that further includes a collector for collecting oil.

According to the oil separator of the present invention, the volume of noise generated when the variable valve operates can be suppressed.

1 is a schematic diagram showing a closed crankcase ventilation system 1; FIG. FIG. 5 is a perspective view of the head cover 5. FIG. FIG. 2 is a perspective view of an oil separator 2. FIG. FIG. 2 is an exploded view of an oil separator 2. FIG. FIG. 2 is a top view of an oil separator 2. FIG. FIG. 2 is a sectional view of an oil separator 2. FIG. 7 is a sectional view taken along line BB in FIG. 6. FIG. 7 is a sectional view taken along line CC in FIG. 6. FIG. 7 is a sectional view taken along line DD in FIG. 6. FIG. 7 is a sectional view taken along line EE in FIG. 6. FIG. 7 is a sectional view taken along line FF in FIG. 6. FIG. FIG. 2 is a cross-sectional view showing a cross section of a protrusion 21a. FIG. 2 is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas. FIG. 2 is a cross-sectional view of the oil separator 2 showing the flow of collected oil. FIG. 3 is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas when the valve 70 is closed. FIG. 3 is a cross-sectional view of the oil separator 2 showing the flow of blow-by gas when the valve 70 is open. 2 is a schematic diagram showing a closed crankcase ventilation system 201. FIG. 3 is a perspective view of an oil separator 202. FIG.

Embodiments of the present invention will be described below with reference to the drawings. However, although various limitations that are technically preferable for carrying out the present invention are attached to the embodiments described below, the scope of the present invention is not limited to the following embodiments and illustrated examples.

==Overview of closed crankcase ventilation system==
FIG. 1 is a schematic diagram of a closed crankcase ventilation system 1 (hereinafter referred to as ventilation system 1). The ventilation system 1 includes an oil separator 2 and a breather pipe 3. The oil separator 2 performs a process of separating oil mist from blow-by gas (an example of gas containing oil mist) discharged into the crankcase of the engine 4. The oil separator 2 is attached so as to be embedded in the upper part of the head cover 5 (an example of a box) of the engine 4. The oil separator 2 returns the separated oil to the engine 4. The breather pipe 3 returns the blow-by gas discharged from the oil separator 2 after oil removal to the intake side flow path 6 of the engine 4. Specifically, the blow-by gas after treatment is returned to a portion of the intake side flow path 5 that connects the air filter 7 and the turbocharger 8. The reduced blow-by gas after oil removal is mixed with outside air from the air filter 7 and compressed by the turbocharger 8. The compressed blow-by gas is cooled by a charge air cooler 9 and then supplied to the engine 4.

The head cover 5 shown in FIG. 2 is a cover that covers the upper part of the cylinder head of the engine 4. In the following description, "above" and "bottom" mean "above" and "below" in FIGS. 2 to 4, and this direction is defined as an up-down direction. The head cover 5 according to the present embodiment has a rectangular parallelepiped shape and has an open bottom surface. The opening portion of the head cover 5 is attached to the upper part of the cylinder head. The head cover 5 has a lower opening 5a, an upper opening 5b, and a mounting hole 5c (see FIG. 2).

The lower opening 5a is an opening for attaching the head cover 5 to the upper part of the cylinder head. The lower opening 5a is a portion where the lower surface of the head cover 5 opens. The lower opening 5a vertically faces the upper part of the cylinder head.

The upper opening 5b is a hole into which the oil separator 2 is attached. The upper opening 5b is provided on the upper surface of the head cover 5. In this embodiment, the upper opening 5b is a circular hole. The number of upper openings 5b is the same as the number of oil separators 2 attached to the head cover 5. In this embodiment, one example is shown.

The attachment hole 5c is a portion into which a fastening member such as a bolt is fitted. The attachment hole 5c is provided on the upper surface of the head cover 5 and near the upper opening 5b. The number of attachment holes 5c is not particularly limited as long as the oil separator 2 can be fixed with a fastening member. In this embodiment, two examples are shown.

==Structure of oil separator==
The oil separator 2 will be explained with reference to FIGS. 3 to 16.
The oil separator 2 includes a case 20, a collection structure 50, a leaf spring 120 (an example of an assembled elastic body), and an oil trap 130 (see FIGS. 3 and 4).

<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 collection structure 50, the leaf spring 120, and the oil trap 130 are arranged.
The case 20 includes a lower case 21 (an example of a first case) and an upper case 22 (an example of a second case).

(lower case)
The lower case 21 is a cylindrical member in the shape of an inverted truncated cone with an open upper end. The lower end surface of the lower case 21 is inclined downward toward the radial center of the lower case 21. The lower case 21 includes a projection 21a, an inflow port 23 (an example of an opening), an oil discharge port 24, an opening 25, a claw 26, a mounting portion 27, a stopper 39, and a groove 21b. , is provided. The lower case 21 is fitted into the upper opening 5b of the head cover 5 (see FIGS. 3, 4, 6, 11, and 12).

The protrusion 21a is a portion that holds the oil trap 130 from below. The protrusion 21a protrudes from the inside of the lower case 21 toward the radial center of the lower case 21 (see FIG. 12). The number of protrusions 21a is not particularly limited as long as the oil trap 130 can be held from below. In this embodiment, six protrusions 21a are provided at intervals in the circumferential direction (see FIG. 11).

The inflow port 23 is a portion for allowing blow-by gas to flow into the interior of the oil separator 2 . The inflow port 23 according to this embodiment is an opening provided in the side surface of the lower case 21. The inflow port 23 allows the internal space and external space of the lower case 21 to communicate with each other. The position and number of inflow ports 23 are not particularly limited as long as blow-by gas can flow into the oil separator 2. In this embodiment, six inflow ports 23 are provided at intervals in the circumferential direction (see FIGS. 3, 4, 6, and 11). The inflow port 23 is provided so as not to face the protrusion 21a in the radial direction when viewed from above.

The oil discharge port 24 is a part through which oil separated from the blow-by gas flows out of the oil separator 2 . The oil discharge port 24 is an opening provided at the center of the lower end surface of the lower case 21. The oil discharge port 24 communicates the internal space of the lower case 21 with the external space.

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.

The claw portion 26 is a portion that attaches the upper case 22 to the lower case 21 by fitting into a hook portion 30 described later. The claw portion 26 is provided on the outer circumferential surface of the lower case 21 near the upper end so as to protrude outward in the radial direction. The position and number of the 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 at intervals in the circumferential direction.

The attachment portion 27 is a portion for attaching the oil separator 2 to the head cover 5. The mounting portion 27 has a flange portion 27a, a cylindrical body 27b, and a mounting hole 27c.

The flange portion 27a extends radially outward from the side surface of the lower case 21. The number of flange portions 27a is the same as the number of attachment holes 5c of head cover 5. In this embodiment, two examples are shown. The two flange portions 27a are provided at opposing positions on the outer side surface of the lower case 21.

The cylindrical body 27b is provided at the end of the flange portion 27a. The number of cylindrical bodies 27b is the same as the number of attachment holes 5c. In this embodiment, two examples are shown. The cylindrical body 27b is provided so that the column axis is in the vertical direction. The cylindrical body 27b is arranged directly above the attachment hole 5c when the lower case 21 is attached to the head cover 5.

The attachment hole 27c is a portion for attaching the oil separator 2 to the head cover 5 by fitting a fastening member into the attachment hole 27c. The attachment hole 27c is a hole that vertically passes through the center of the cylindrical body 27b. The number of attachment holes 27c is the same as the number of attachment holes 5c of the head cover 5. In this embodiment, two examples are shown.

The stopper portion 39 is a portion that determines the vertical position of the lower case 21 with respect to the upper opening 5b of the head cover 5. The stopper portion 39 is an annular and plate-shaped portion. The stopper portion 39 is provided on the outer side surface of the lower case 21. The outer diameter of the stopper portion 39 is larger than the diameter of the upper opening 5b. The position of the lower surface of the stopper portion 39 is equal to the position of the lower surface of the cylindrical body 27b. The stopper portion 39 is provided above the inflow port 23.

The groove 21b is a portion where an O-ring 32a, which will be described later, is arranged. The groove 21b is provided in the outer side surface of the lower case 21 in the circumferential direction. In the example of FIG. 6, the groove 21b is provided near the bottom of the stopper portion 39. An O-ring 32a is arranged in the groove 21b. By fitting the lower case 21 into the head cover 5 with the O-ring 32a disposed in the groove 21b, the O-ring 32a is sandwiched between the head cover 5 and the lower case 21 to seal the space between them.

The lower case 21 is fitted into the upper opening 5b from above. At this time, the lower case 21 is fitted into the upper opening 5b so that the axes of the attachment hole 5c of the head cover 5 and the attachment hole 27c of the lower case 21 are aligned. Then, the lower surface of the stopper portion 39 comes into contact with the edge of the upper opening 5b, and the vertical position of the lower case 21 is determined. The lower case 21 is fixed to the head cover 5 by attaching the bolts 5d to the attachment holes 5c and 27c.

In a state where the lower case 21 is fixed to the head cover 5 , a portion of the lower case 21 below the stopper portion 39 is arranged in the internal space of the head cover 5 . Therefore, the internal space of the lower case 21 communicates with the internal space of the head cover 5 through the inflow port 23. Further, the internal space of the lower case 21 communicates with the internal space of the head cover 5 through the oil discharge port 24.

(upper case)
The upper case 22 is provided so as to close the opening 25 of the lower case 21. The upper case 22 includes an outer cylinder 28, a discharge port 29, a hook part 30, a flange part 31, a stopper part 33, a large diameter cylinder 34, a small diameter cylinder 35, a lid part 36, and an opening. 37, a first connection part 38a, a second connection part 38b, and a PCV valve 40 (see FIGS. 3 to 6).

The outer cylinder 28 is a member that closes the opening 25. The outer cylinder 28 is a substantially cylindrical member having a closed upper end and an open lower end. Upper case 22 is attached to lower case 21 such that opening 28 a at the lower end of outer cylinder 28 faces opening 25 of lower case 21 .

The flange part 31 is a part for arranging the hook part 30. The flange portion 31 is an annular portion extending radially outward from the side surface of the outer cylinder 28.

The hook portion 30 is a portion that fits into 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 downward from the outer edge of the flange portion 31. The position and number of the hook parts 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 at intervals in the circumferential direction.

The stopper portion 33 is a portion that restricts movement of the O-ring 32b. 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 . An O-ring 32b is arranged on the lower surface of the stopper part 33 to seal between the lower case 21 and the upper case 22.

The large diameter cylindrical body 34 is a part that partitions the inside of the upper case 22. The large diameter cylinder 34 is a cylindrical portion having a smaller diameter than the outer cylinder 28. The large diameter cylinder 34 is arranged inside the outer cylinder 28.

The small diameter cylindrical body 35 is a part that partitions the inside of the upper case 22 together with the large diameter cylindrical body 34 . The small diameter cylinder 35 is a cylindrical portion having a smaller diameter than the large diameter cylinder 34. The small diameter cylinder 35 is arranged inside the large diameter cylinder 34.

The lid portion 36 is a portion 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. The lid portion 36 and the small diameter cylinder 35 partition the space inside the upper case 22 .

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 an opening at the upper end of the small diameter cylindrical body 35.

The first connecting portion 38a is a portion that joins the large-diameter cylindrical body 34 and the cylindrical body 28 to prevent passage of blow-by gas. The first connecting portion 38a is an annular plate member. In this embodiment, the first connecting portion 38a is provided from the upper end of the large-diameter cylinder 34 toward the inner circumferential surface of the cylinder 28.

The second connecting portion 38b is a portion where the small diameter cylindrical body 35 and the large diameter cylindrical body 34 are joined. The second connecting portion 38b is a rectangular plate. The position and number of the second connecting portions 38b are not particularly limited as long as the small diameter cylindrical body 35 and the large diameter cylindrical body 34 can be joined. In this embodiment, the second connecting portions 38b are provided from the lower end of the large-diameter cylindrical body 34 toward the outer circumferential surface of the small-diameter cylindrical body 35, and three second connecting portions 38b are provided at intervals in the circumferential direction.

The discharge port 29 is a part for allowing the blow-by gas after oil removal to flow out from the inside of the oil separator 2 . The discharge port 29 according to this embodiment has a cylindrical shape. One discharge port 29 is provided so as to extend radially outward from the side surface of the small diameter cylinder body 35, passing through the side surface of the large diameter cylinder body 34 and the side surface of the outer cylinder 28, and extending to the outside of the outer cylinder 28. It will be done. The internal space of the discharge port 29 communicates with the internal space of the small diameter cylindrical body 35 . The breather pipe 3 is connected to the discharge port 29.

The PCV valve 40 is a member for opening and closing the opening 37 of the small diameter cylinder 35. The PCV valve 40 includes a diaphragm valve 41 and a spring 42 (see FIG. 6).

Diaphragm valve 41 opens and closes opening 37 . The diaphragm valve 41 is a disc-shaped portion. 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.

The valve portion 41a is a portion that opens and closes the opening portion 37. The shape of the valve portion 41a according to this embodiment is a disc-shaped portion. The valve portion 41a is provided above the opening portion 37.

The membrane portion 41b is a portion that connects the valve portion 41a and the outer cylinder 28. The membrane portion 41b is an annular portion that is elastically deformed. The membrane portion 41b connects the radially outer end of the valve portion 41a and the inner peripheral surface of the outer cylinder 28.

The spring 42 supports the valve portion 41a in a vertically movable manner. The spring 42 is a coiled spring. The spring 42 is sandwiched between the valve part 41a and the lid part 36 inside the small diameter cylinder 35 and below the valve part 41a, and urges the valve part 41a upward.

The inside of the upper case 22 is partitioned by a small diameter cylinder 35 and a lid part 36. The space between the lower side of the small-diameter cylinder 35 and the lid 36 and the outer cylinder 28 corresponds to an upper upstream space S4, and the inner space between the inside of the small-diameter cylinder 35 and the upper side of the lid 36 corresponds to an upper downstream space. Corresponds to S5.

When the spring 42 contracts, the membrane portion 41b is elastically deformed and expanded, and only the valve portion 41a moves downward, so that the valve portion 41a and the upper end of the small diameter cylinder 35 come into contact. As a result, the opening 37 is closed, and the upper upstream space S4 and the upper downstream space S5 are in a state of being cut off from each other. On the other hand, when the spring 42 extends, the membrane portion 41b elastically deforms and contracts, the valve portion 41a moves upward, and the upper end of the small diameter cylinder 35 separates from the valve portion 41a. As a result, the opening 37 is opened, and the upper upstream space S4 and the upper downstream space S5 are brought into communication with each other.

<Collection structure>
The collection structure 50 is a structure for separating mist 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 pressing member 110, and a check valve 140 (see FIGS. 4 and 6).

(Main body)
The main body part 60 is a part that constitutes a cylindrical frame that is the basic part of the collection structure 50. The main body part 60 has an annular disk part 61, a small diameter cylinder part 62, a large diameter cylinder part 63, a flange part 64, a square cylinder part 66, and a cylinder part 69 (see FIGS. 4 and 13). ). Note that in FIG. 13, for the purpose of explanation, the main body portion 60 is rotated by 45 degrees in the circumferential direction with respect to the cross-sectional view of FIG. 6, so the second connecting portion 38b of the upper case 22 is not displayed.

The annular disk portion 61 is a portion that connects the small diameter cylindrical portion 62 and the large diameter cylindrical portion 63. The annular disk portion 61 is an annular and plate-shaped portion with a through hole formed in the center.

The small-diameter cylindrical portion 62 is a portion that constitutes the upper portion of the main body portion 60 . The small diameter cylindrical portion 62 is a cylindrical portion. The diameter of the small diameter cylindrical portion 62 is equal to the inner diameter of the annular disk portion 61. The small diameter cylindrical portion 62 protrudes upward along the radially inner edge of the annular disk portion 61 . Both the upper and lower ends of the small diameter cylindrical portion 62 are open.

The large-diameter cylindrical portion 63 is a portion that constitutes the central portion of the main body portion 60 . The large diameter cylindrical portion 63 is a cylindrical portion. 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 disk portion 61 .

The flange portion 64 is a portion that constitutes the lower portion 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. Furthermore, a groove 64a that opens radially outward is formed in the flange portion 64 in the circumferential direction. An O-ring 65 is disposed in the groove 64a to seal between the flange portion 64 and the lower case 21.

The square tube part 66 is a part that forms a square tube-shaped internal space. The square tube portion 66 is a square tube-shaped portion with a substantially square cross section. The square tube portion 66 is provided between the lower surface of the annular disk portion 61 and the upper surface of the flange portion 64 . The square 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 opposite side in the radial direction. The square 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 square tube portion 66 has a central wall portion 66a, a through hole 67, and a hole 68 (see FIGS. 4, 6, and 10).

The central wall portion 66a is a portion that partitions the internal space of the square tube portion 66. The center wall portion 66a has a central portion that bulges in the radial direction when viewed from above, and the rest is a plate-shaped portion. The center wall portion 66a is provided at the center in the radial direction inside the square tube portion 66. Thereby, the internal space S6 is partitioned into two.

The through hole 67 is a hole into which the check valve 140 is attached. The through hole 67 is a hole that vertically passes through a portion where the center portion of the central wall surface portion 66a bulges in the radial direction.

The hole 68 is a hole that communicates the internal space S6 of the square tube portion 66 with the external space. The hole 68 is a hole that vertically passes through the lower surface of the square tube portion 66. The hole 68 is provided near the center wall portion 66a.

The cylindrical portion 69 is a portion from which droplet-shaped oil, which will be described later, flows downward. The cylindrical portion 69 is a cylindrical portion. The cylindrical portion 69 extends downward from the lower surface of the square cylindrical portion 66 (see FIGS. 6 and 13).

By fitting the main body 60 into the lower case 21 from above, the main body 60 partitions the internal space of the lower case 21 into a space on the inflow port 23 side and a 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 a space on the inflow port 23 side that includes the internal space of the main body 60, of the internal space of the lower case 21 partitioned by the main body 60. The downstream space S3 is a space between the collection structure 50 and the lower case 21 in the space on the opening 25 side of the internal space of the lower case 21 partitioned by the main body 60.

(non-return valve)
The check valve 140 is a valve that opens and closes the hole 68 of the main body portion 60 (specifically, the rectangular tube portion 66). The check valve 140 includes a valve body 141, a shaft portion 142, and a stopper portion 143 (see FIGS. 6, 10, and 13).

The valve body 141 is a part that opens and closes the hole 68. The valve body 141 is a circular plate member. The position and number of the 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 square tube portion 66 so as to cover the hole 68 .

The shaft portion 142 is a portion that restricts the moving direction of the valve body 141. The shaft portion 142 is a rod-shaped portion. 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 square tube portion 66. Thereby, the shaft portion 142 becomes movable 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.

The stopper portion 143 is a portion that restricts the amount of vertical movement of the valve body 141 and the shaft portion 142. The stopper portion 143 is a portion of the shaft portion 142 that bulges in the radial direction. The stopper portion 143 is provided at a portion of the shaft portion 142 that is a specific distance above the upper surface of the valve body 141 . Here, the specific distance is the sum of the length of the through hole 67 in the vertical direction and the amount by which the valve body 141 is moved in the vertical direction. 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, and the downward movement of the valve body 141 is restricted.

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 (that is, the pressure of the upstream space S1) acts on the lower surface of the valve body 141. If the pressure in the internal space S6 is greater than the pressure in the upstream space S1, the valve body 141 moves downward and opens the hole 68. On the other hand, when the flow rate of the 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. .

(valve)
The valve 70 is a valve that adjusts the flow rate of blow-by gas flowing from the upstream space S1. The valve 70 is disposed above the upper end opening of the small diameter cylindrical portion 62 of the main body portion 60 so as to be vertically opposed to each other. By moving downward, the valve 70 contacts the upper end of the small diameter cylindrical portion 62, which is a valve seat, and closes the upper end opening of the small diameter cylindrical portion 62. The valve 70 opens the upper end opening of the small diameter cylindrical portion 62 by moving upward, and a gap is formed between the valve 70 and the upper end opening of the small diameter cylindrical portion 62 . The valve 70 includes a valve body 71, a cylindrical portion 73, a spring 74, a hole 75, and a stopper portion 76 (see FIGS. 6, 8, 15, and 16). 15 and 16, the main body 60 is rotated by 45 degrees in the circumferential direction and the valve 70 is rotated by 90 degrees in the circumferential direction with respect to the cross-sectional view of FIG. 6 for the sake of explanation.

The valve body 71 is a valve body 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 arranged above the upper end opening of the small diameter cylindrical portion 62 of the main body portion 60 . By moving the valve body 71 up and down, the upper end opening of the small diameter cylindrical portion 62 opens and closes. The valve body 71 has a valve elastic body 72 .

The valve elastic body 72 cushions 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 annular member having elasticity. The valve elastic body 72 is provided along the outer peripheral edge of the lower surface of the valve body 71. The valve elastic body 72 comes into contact with the upper end opening of the small diameter cylindrical portion 62 when the valve body 71 moves downward. When the valve body 71 moves upward, the valve elastic body 72 separates upward from the upper end opening of the small diameter cylindrical part 62, and an annular gap is formed between the valve elastic body 72 and the upper end of the small diameter cylindrical part 62. Ru. When the blow-by gas flows into the upstream space S1, this gap becomes the first flow path C1 for the blow-by gas. The size of this gap changes depending on the vertical position of the valve body 71. That is, the first channel C1 is a channel whose opening degree changes.

The cylindrical portion 73 is a portion that lowers the center of gravity of the valve 70 and makes it difficult for the valve 70 to tilt relative to the main body portion 60 when an uneven force is applied to the valve 70. The cylindrical portion 73 is a cylindrical portion. 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 within the upstream space S1. Note that a configuration may be adopted in which the cylindrical portion 73 is not provided in the valve body 71.

The hole 75 is a portion for allowing the blow-by gas in the upstream space S1 to flow out regardless of whether the valve 70 is opened or closed. The hole 75 is a hole that allows communication between the outer space of the valve body 71 and the inner space of the cylindrical portion 73 (see FIGS. 15 and 16). The hole 75 is provided from the side surface of the valve body 71 to the internal space of the cylindrical portion 73 . When the blow-by gas flows into the internal space of the cylindrical portion 73, the hole 75 becomes a second flow path C2 for the blow-by gas. The size of the hole 75 does not change depending on the flow rate of the blow-by gas flowing into the internal space of the cylindrical portion 73 . That is, the second flow path C2 is a flow path with a constant opening degree.

The spring 74 supports the valve body 71 in a vertically movable manner. The spring 74 is a coiled spring. The spring 74 is arranged 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 disk portion 111 of the pressing member 110, which will be described later, and urges the valve body 71 downward.

The stopper portion 76 comes into contact with the lower surface of a cylindrical portion 114 of a pressing member 110, which will be described later, and restricts the amount of vertical movement of the valve body 71. The stopper portion 76 according to this embodiment has a cross shape (see FIG. 8). The stopper portion 76 projects upward from the top surface of the valve body 71. When the valve body 71 moves upward, the stopper part 76 comes into contact with the lower surface of the cylindrical part 114, and prevents the valve body 71 from moving further upward.

Here, the first flow path C1 and the second flow path C2 will be explained. The inlet of the first flow path C1 is the internal space (upstream space S1) of the small diameter cylindrical portion 62. The outlet of the first flow path C1 is outside the small diameter cylindrical portion 62 and outside the valve 70. The entrance of the second flow path C2 is the internal space (upstream space S1) of the cylindrical portion 73. The outlet of the second channel C2 is outside the valve 70.

(collector)
The collector 80 is a member that has air permeability and separates mist-like oil from blow-by gas. The collector 80 is, for example, a nonwoven fabric. The collector 80 faces the outlet of the first channel C1 and the outlet of the second channel C2 in the radial direction (see FIGS. 4, 6, 9, and 13). In the internal space of the lower case 21 partitioned by the main body part 60, the space between the collector 80 and the outside of the valve 70 and the outside of the small diameter cylinder part 62 in the space on the opening 25 side is defined as a downstream space S2.

(Holding member)
The holding member 90 is a member for holding the collector 80. In this embodiment, the holding member 90 holds the collector 80 by sandwiching it from the outside and the inside in the radial direction. Specifically, the holding member 90 includes a bar 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 (FIG. 4, (See FIGS. 6, 8, 9, and 13).

The rod 91 is a member that supports the collector 80 from the outside in the radial direction. The number of rods 91 is not particularly limited as long as it has the effect of supporting the collector 80 from the outside in the radial direction. In this embodiment, four examples are shown (see FIG. 9). The rods 91 are provided on the upper surface of the annular disk portion 61 of the main body portion 60 at intervals in the circumferential direction. The bar 91 extends upward from the upper surface of the annular disk portion 61 (see FIG. 4).

The column member 92 is a member that supports the collector 80 from the outside in the radial direction. Moreover, the pillar member 92 is a member to which the pressing member 110 is attached. The column members 92 are provided on the upper surface of the annular disk portion 61 of the main body portion 60 at intervals in the circumferential direction, and are provided between the two bar members 91 in the circumferential direction. That is, the column members 92 and the bars 91 are provided alternately in the circumferential direction along the outer periphery of the collector 80. The column member 92 extends upward from the upper surface of the annular disk portion 61 (see FIG. 4). The number of pillar members 92 is not particularly limited as long as it supports the collector 80 from the outside in the radial direction and allows the pressing member 110 to be attached. In this embodiment, four examples are shown (see FIG. 9).

The column member 92 has a protrusion 94 . The protruding portion 94 is a portion to which the pressing member 110 is attached. The protruding portion 94 is a portion that protrudes from the upper surface of the column member 92. The protrusions 94 are provided on the upper surfaces of two of the four pillar members 92 that are radially opposed to each other (see FIGS. 4 and 8).

The inner holding member 93 is a member that supports the collector 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 disk portion 61 of the main body portion 60 at intervals in the circumferential direction, and is arranged so as not to face the bar 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 disk portion 61 (see FIG. 4). The number of inner holding members 93 is not particularly limited as long as it has the effect of supporting the collector 80 from the inside in the radial direction. In this embodiment, eight examples are shown (see FIG. 9).

The lower support member 100 is a member that supports the collector 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 disk portion 61 of the main body portion 60 at intervals in the circumferential direction. The number of lower support members 100 is not particularly limited as long as it has the function of supporting the collector 80 from below. In this embodiment, 16 examples are shown (see FIGS. 4 and 9). The outer end of the lower support member 100 is joined to the bar 91 or the column member 92, and the inner end is joined to the inner holding member 93.

The bar 91, the column member 92, and the inner holding member 93 hold the collector 80 by sandwiching it in the radial direction. As described above, the bar 91 and the column member 92 support the collector 80 from the outside in the radial direction. The inner holding member 93 supports the collector 80 from the inside in the radial direction. Thereby, the collecting body 80 is arranged in an annular shape so as to surround the valve 70 at a distance from the outer circumferential side. Note that the holding member 90 may be formed of any one of a bar 91, a column member 92, and an inner holding member 93, or a combination of the two, as long as the holding member 90 can support the collector 80. For example, the holding member 90 may be one in which only the bar 91 is provided on the outer periphery of the collector 80. Further, the number and shape of the bar 91, the column member 92, and the inner holding member 93 are not limited to those described above, and can be freely changed.

(holding member)
The pressing member 110 is a member that presses the spring 74 from above. However, in this embodiment, the pressing member 110 also supports the collector 80 from above. The holding member 110 includes a disk portion 111, a columnar surface portion 112, a flange portion 113, a cylindrical portion 114, and a projection portion 116 (see FIGS. 4, 6, and 8).

The disk portion 111 is a portion that presses the spring 74 from above. The disk portion 111 is a circular plate member having a smaller outer diameter than the annular disk portion 61 of the main body portion 60 (see FIG. 6). The lower surface of the disc portion 111 presses the spring 74 from above.

The cylindrical portion 114 is a portion that restricts movement of the spring 74 in the radial direction. The cylindrical portion 114 is a cylindrical portion with an open bottom end (see FIG. 6). The cylinder portion 114 is provided on the lower surface of the disk portion 111. A spring 74 is arranged around the outer periphery of the cylindrical portion 114. Therefore, the movement of the spring 74 in the radial direction is restricted. Moreover, when the valve 70 moves upward, the stopper part 76 comes into contact with the lower end of the cylindrical part 114. This limits the amount of upward movement of the valve 70.

The protrusion 116 is a portion that restricts movement of the leaf spring 120 in the radial direction. The protruding portion 116 is a portion of the upper surface of the disc portion 111 that protrudes upward. The protrusions 116 are provided on the upper surface of the disc portion 111 at intervals in the circumferential direction. The number of protrusions 116 is not particularly limited as long as the protrusions 116 have the effect of restricting movement of the leaf spring 120 in the radial direction. In this embodiment, four examples are shown (see FIG. 4).

The columnar surface portion 112 is a portion that joins the disk portion 111 and the flange portion 113 in the vertical direction. The columnar surface portion 112 is a plate-shaped portion. The columnar surface portions 112 are provided on the outer edge of the disk portion 111 at intervals in the circumferential direction. The columnar surface portion 112 extends downward along the outer edge of the disk portion 111 to the height of the upper surface of the collector 80 . The number of columnar parts 112 is not particularly limited as long as it has the effect of joining the disc part 111 and flange part 113 in the vertical direction. In this embodiment, eight examples are shown (see FIG. 8).

The flange portion 113 is a member that supports the collector 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 the flange portions 113 have the function of supporting the collector 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 in which the number of flange portions 113 is eight (see FIG. 8). 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 collector 80 and supports the collector 80 from above. The flange portion 113 holds the collector 80 by vertically sandwiching it together with the lower holding member 100. The flange portion 113 has a groove portion 115.

The groove portion 115 is a portion that fits into the protrusion portion 94 of the column member 92. The groove portions 115 are grooves provided in the two radially opposing flange portions 113, respectively. The groove portion 115 is provided to open radially outward in the flange portion 113 and to vertically penetrate through the flange portion 113 . The groove 115 fits into the protrusion 94 . Thereby, the holding member 110 is assembled to the main body portion 60 via the protrusion portion 94 and the column member 92.

<Leaf spring>
The leaf spring 120 is a member that generates a repulsive force proportional to the amount of compression. The leaf spring 120 is an annular member made of metal, and is formed into a corrugated shape at the top and bottom. Therefore, when the leaf spring 120 is compressed vertically, it generates a repulsive force. One leaf spring 120 is disposed on the upper surface of the disc portion 111 and on the inner diameter side of the plurality of projections 116 . The leaf spring 120 is sandwiched between the upper surface of the disk portion 111 and the lower surface of the lid portion 36, and is compressed vertically (see FIGS. 4 and 6). As a result, the leaf spring 120 generates a repulsive force, and applies a downward force through the disc portion 111 to the collection structure 50 and the lower case 21 in which the collection structure 50 is fitted. Further, the repulsive force generated by the leaf spring 120 exerts an upward force on the upper case 22 through the lid portion 36, the small diameter cylindrical body 35, and the discharge port 29.

Due to the leaf spring 120, a downward force acts on the lower case 21, and an upward force acts on the upper case 22. Here, the upper case 22 is assembled to the lower case 21 by fitting the hook part 30 into the claw part 26 of the lower case 21, but due to variations in the dimensions of the hook part 30 and the claw part 26, the fitting part Shaking may occur. In contrast, according to the present embodiment, the leaf spring 120 applies a downward force to the lower case 21 and an upward force to the upper case 22 (that is, a repulsive force in the direction of vertically separating both cases). ), the upper case 22 can be assembled to the lower case 21 without wobbling.

<Oil trap>
The oil trap 130 separates oil mist from the blow-by gas. The oil trap 130 is an annular member (see FIGS. 4, 6, and 12). The oil trap 130 has an annular surface portion 131 and an inclined surface portion 132 (an example of a surface portion).

The annular surface portion 131 determines the position of the oil trap 130. The annular surface portion 131 is a plate-shaped portion formed in an annular shape. The annular surface portion 131 is placed on the protrusion 21a. The oil trap 130 is held by the outer peripheral side of the annular surface portion 131 being sandwiched between the upper surface of the protrusion 21a and the lower surface of the flange portion 64 (see FIG. 12).

The inclined surface portion 132 is a plate-shaped portion formed in an annular shape. The inclined surface portion 132 is tapered downward. The inclined surface portion 132 is provided on the inner peripheral edge of the annular surface portion 131 . The inclined surface portion 132 is arranged to face the inflow port 23 in the radial direction. Note that the inclined surface portion 132 may extend vertically downward from the inner peripheral edge of the annular surface portion 131. The lower end of the inclined surface portion 132 is spaced upward from the lower case 21 to form a gap.

The gap 133 is a gap between the lower end of the inclined surface portion 132 and the lower case 21. Hereinafter, the space from the inflow port 23 to the gap 133 will be referred to as an inlet space S0, and the space downstream of the slope portion 131 will be referred to as an upstream space S1. The gap 133 functions as a flow path C0 through which blow-by gas flows from the inlet space S0 toward the upstream space S1.

==Flow of blow-by gas==
Here, the flow of blow-by gas will be explained. The black arrows in FIGS. 13 to 16 indicate the flow of blow-by gas. The blow-by gas flows from the internal space of the head cover 5 through the inflow port 23 into the inlet space S0.

The blow-by gas flowing into the inlet space S0 collides with the inclined surface portion 132 disposed opposite the inflow port 23, and the direction of flow changes. On the other hand, some of the mist oil contained in the blow-by gas (particularly mist oil with large oil droplets) cannot keep up with the change in the direction of the gas flow and collides with the inclined surface section 132, causing the surface of the inclined surface section 132 to It is separated from the blow-by gas by coagulation at the top. As a result, the concentration of oil mist in the blow-by gas flowing out from the inlet space S0 is lower than the concentration of oil mist in the blow-by gas flowing into the inlet space S0 (that is, the blow-by gas in the internal space of the head cover 5). The blow-by gas with a lower concentration of mist oil flows into the upstream space S1 through the flow path C0 (gap 133).

Here, the flow rate of the blow-by gas flowing into the upstream space S1 changes depending on the operating state of the engine 4 and the like. As shown in FIG. 15, when the flow rate of the blow-by gas flowing into the upstream space S1 is small, the pressure of the blow-by gas in the upstream space S1 is low, so the valve 70 is closed. Specifically, since 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 close and close the upper end opening of the small diameter cylindrical portion 62, thereby closing the upper end opening of the small diameter cylindrical portion 62. is in a closed state. In this case, the blow-by gas flows into the external space S2 only through the second flow path C2.

On the other hand, when the flow rate of the 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 level, as shown in FIG. C1 is formed. Specifically, when the pressure of the blow-by gas in the upstream space S1 increases, the upward force acting on the valve body 71 due to the pressure of the blow-by gas in the upstream space S1 is greater than the downward force acting on the valve body 71 due to the spring 74. also becomes larger. Therefore, the valve body 71 moves upward, and the valve elastic body 72 is separated upward from the upper end of the small diameter cylindrical portion 62, so that the upper end opening of the small diameter cylindrical portion 62 is opened. In this case, the blow-by gas flows into the external space S2 through both the first flow path C1 and the second flow path C2.

Note that the higher the pressure of the blow-by gas in the upstream space S1, the greater the amount of upward movement of the valve body 71, and the larger the amount of upward movement of the valve body 71 becomes. The size of C1 also increases. That is, the opening degree of the first blow-by gas flow path C1 increases as the pressure of the blow-by gas in the upstream space S1 increases.

As described above, the larger the flow rate of the blow-by gas flowing into the upstream space S1, the larger the opening degree of the valve 70 (that is, the opening degree of the first flow path C1). Therefore, when the flow rate of the blow-by gas flowing into the upstream space S1 is large, the opening degree of the valve 70 (that is, the opening degree of the first flow path C1) is large, so that the flow rate of the blow-by gas flowing through the first flow path C1 is becomes larger. On the other hand, the smaller the flow rate of the blow-by gas flowing into the upstream space S1, the smaller the opening degree of the valve 70 (that is, the opening degree of the first flow path C1). Therefore, when the flow rate of the blow-by gas flowing into the upstream space S1 is small, the opening degree of the valve 70 (that is, the opening degree of the first flow path C1) is small, so the flow rate of the blow-by gas flowing through the first flow path C1 is becomes smaller. Furthermore, since the cross-sectional area of the first flow path C1 becomes smaller, the flow rate of the blow-by gas flowing through the first flow path C1 becomes faster.

When the flow rate of the blow-by gas flowing into the upstream space changes, the opening degree of the valve also changes. At this time, since the valve repeats reciprocating motion without stopping, pulsations occur in the blow-by gas due to this reciprocating motion. However, since the second flow path C2 is provided in the valve 70, when the blow-by gas flows into the upstream space at the same flow rate, the valve 70 is The opening becomes smaller. Therefore, the magnitude of the blow-by gas pulsations accompanying the reciprocating movement of the valve 70 becomes smaller.

When the valve closes, the valve body collides with the valve seat, producing a tapping sound. When a valve is closed from a large opening, the valve body collides with the valve seat with force, producing a loud banging sound. However, since the second flow path C2 is provided in the valve 70, when the blow-by gas flows in at the same flow rate, the opening degree of the valve 70 is smaller than that of a valve that is not provided with the second flow path C2. By making the valve smaller, it is possible to reduce the magnitude of the tapping sound generated by the collision between the valve 70 and the valve seat (the upper end opening of the small diameter cylindrical portion 62).

Further, the valve 70 is provided with a valve elastic body 72 at a portion that contacts the main body portion 60 . Therefore, when the valve 70 collides with the main body part 60, the impact of the collision is alleviated by the valve elastic body 72, so that the magnitude of the hitting sound generated when the valve 70 and the main body part 60 collide can be further reduced. .

As described above, when the valve 70 is closed, the blow-by gas does not stay in the upstream space S1 but flows through the second flow path C2 to the external space S2. Therefore, since the blow-by gas is difficult to stay in the upstream space S1, the pressure of the blow-by gas in the upstream space S1 is difficult to rise compared to the case where the second flow path C2 is not provided. In other words, the pressure of the blow-by gas in the upstream space S1 exceeds a certain level, and the flow rate of the blow-by gas necessary for the valve 70 to be in the open state increases, so the frequency in which the valve 70 is in the open state is low. Become.

On the other hand, when the valve is open and the flow rate of the blow-by gas flowing into the upstream space changes, the magnitude of the force acting on the valve changes due to the pressure of the blow-by gas. At this time, if the magnitude of the force acting on the valve becomes uneven depending on the portion of the valve, the valve tends to tilt with respect to the main body. However, since a part of the blow-by gas flows through the second flow path C2 to the external space S2, the blow-by gas flowing into the upstream space S1 is larger than when the valve 70 is not provided with the second flow path C2. Fluctuations in blow-by gas pressure caused by fluctuations in gas flow rate become smaller. In other words, fluctuations in the magnitude of the force acting on the valve 70 due to the pressure of the blow-by gas become smaller.

Next, the flow of the blow-by gas after passing through the first flow path C1 and the second flow path C2 will be explained using FIG. 14. In FIG. 14, the main body portion 60 is rotated by 15 degrees in the circumferential direction with respect to the cross-sectional view of FIG. 6 for explanation.

As shown in FIG. 14, the blow-by gas flows into the external space S2 through the first flow path C1 or the second flow path C2, and faces the outlet of the first flow path C1 and the second flow path C2. collides with the collector 80 that is While the blow-by gas passes through the collector 80, the oil mist contained in the blow-by gas is collected by the collector 80 and separated. The oil-removed blow-by gas from which mist-like oil has been separated by passing through the collector 80 flows into the downstream space S3 through the gap between the rod member 91 and the column member 92.

The blow-by gas contains not only mist oil but also garbage such as sludge. In the conventional collection structure, the blow-by gas does not pass through the collector, so it cannot blow away the dust attached to the collector. As a result, garbage was deposited on the collector. However, according to the present embodiment, since the blow-by gas passes through the collector 80, the blow-by gas can blow away the dust attached to the collector 80. Note that when the flow rate of the blow-by gas flowing into the upstream space S1 is large, the flow rate of the blow-by gas flowing through the first channel C1 becomes high. Therefore, the dust attached to the collector 80 is easily blown away by the blow-by gas. Further, when the flow rate of the blow-by gas flowing into the upstream space S1 is small, the opening degree of the valve 70 becomes small and the flow rate of the blow-by gas flowing through the first channel C1 becomes high. Therefore, the dust attached to the collector 80 is blown away by the blow-by gas.

The blow-by gas after oil removal flows from the downstream space S3 to the upper upstream space S4, as shown in FIG. Here, if the PCV valve 40 is in a closed state, the blow-by gas after oil removal remains in the upper upstream space S4. On the other hand, if the PCV valve 40 is in an open state, the blow-by gas after oil removal flows to the upper downstream space S5. The blow-by gas after oil removal flows into the breather pipe 3 through the exhaust port 29.

Since the upper downstream space S5 is connected to the engine 4 through the exhaust port 29 and the breather pipe 3, the intake pressure (negative pressure) of the engine 4 becomes high and the force that pulls the valve part 41a of the diaphragm valve 41 downward is generated by the spring. When the elastic force becomes larger than the elastic force of 42, the opening degree of the PCV valve 40 becomes smaller. Further, when the intake pressure of the engine 4 becomes even higher, the valve portion 41a comes into contact with the upper end of the small diameter cylinder 35, and the PCV valve 40 is completely closed. On the other hand, when the intake pressure of the engine 4 becomes low and the elastic force of the spring 42 becomes greater than the force that pulls the valve portion 41a downward, the opening degree of the PCV valve 40 increases.

As described above, when the intake pressure (negative pressure) of the engine 4 is excessively high, the opening degree of the PCV valve 40 becomes small, and the flow rate of blow-by gas flowing into the upper downstream space S5 decreases. On the other hand, when the pressure on the crankcase side of the engine 4 is high, the opening degree of the PCV valve 40 increases, and the flow rate of blow-by gas flowing into the upper downstream space S5 increases. Thereby, the flow rate of the blow-by gas is appropriately adjusted by the PCV valve 40. Moreover, the pressure within the crankcase of the engine 4 is also appropriately adjusted.

Note that the blow-by gas includes water vapor. Therefore, water vapor also adheres to the collector 80. In a low-temperature environment, water vapor adhering to the collector 80 may freeze, and the blow-by gas may not be able to pass 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 allows external space S2 and downstream space S3 to communicate with each other. Further, since the flange portions 113 are provided at intervals in the circumferential direction, a gap is formed between the flange portions 113 on the upper side of the collector 80. This gap allows external space S2 and downstream space S3 to communicate with each other. Therefore, even if the water vapor adhering to the collector 80 freezes and the blow-by gas cannot pass through the collector 80, the blow-by gas collides with the collector 80 and changes the flow direction up or down, causing the blow-by gas to pass through the collector 80. It flows from the outer space S2 to the downstream space S3 through the gaps formed above and below. Note that when the blow-by gas collides with the collector 80 and changes its direction of flow up and down, the mist-like oil contained in the blow-by gas cannot keep up with the change in the flow direction and collides with the collector 80 and is collected. It is separated from the blow-by gas.

==Flow of oil==
Next, the flow of the mist-like oil separated from the blow-by gas by the oil trap 130 will be explained using FIG. 13. White arrows indicate the flow of mist-like oil. The mist-like oil separated from the blow-by gas flows downward by gravity to the end surface of the lower case 21 on the oil discharge port 24 side. Since this end face is inclined toward the oil discharge port 24, mist-like oil flows to the oil discharge port 24. Then, the mist-like oil flows from the oil discharge port 24 to the internal space of the head cover 5.

Next, the flow of the mist-like oil separated from the blow-by gas by the collector 80 will be explained using FIG. 14. White arrows indicate the flow of oil droplets. The mist-like oil separated from the blow-by gas by the collector 80 aggregates to become oil droplets. As shown in FIG. 14, the oil droplets flow from the collector 80 to the downstream space S3 due to the flow of blow-by gas flowing radially outward in the collector 80 and by gravity. The droplet-shaped oil that has flowed into the downstream space S3 flows further downward into the internal space S6.

The oil droplets flow through the interior space S6 and into the holes 68. The hole 68 is opened and closed by a check valve 140. As described above, when the pressure in the upstream space S1 on the lower surface side of the valve element 141 is higher than the pressure in the internal space S6 on the upper surface side of the valve element 141, the valve element 141 is pushed up and the hole 68 is closed. Therefore, the 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 is opened. At this time, the droplet-shaped oil flows through the hole 68 to the upstream space S1. The droplet-shaped oil then flows down along the inside of the cylindrical portion 69 and flows to the end surface of the lower case 21 on the oil discharge port 24 side. The droplet-shaped oil then flows to the oil discharge port 24 and flows into the internal space of the head cover 5 through the oil discharge port 24.

As described above, part of the mist-like oil is separated from the blow-by gas that has flowed into the upstream space S1 by the oil trap 130. Therefore, the concentration of the mist oil in the blow-by gas that collides with the collector 80 is lower than the concentration of the mist oil in the blow-by gas in the internal space of the head cover 5 . Therefore, since the amount of mist oil collected by the collector 80 is reduced, the collector 80 can separate the mist oil from the blow-by gas within the range of its collection capacity. Moreover, the mist-like oil collected by the collector 80 aggregates and becomes oil droplets, and then flows to the downstream space S3 and the internal space S6. Since the amount of mist-like oil collected by the collector 80 decreases, the amount of oil droplet-like oil flowing into the downstream space S3 and the internal space S6 also decreases.

<Effect>
In this embodiment, an oil separator 2 includes a collection structure 50 that collects mist-like oil from blow-by gas, and a case 20 having an internal space that accommodates the collection structure 50. The body 50 communicates with a main body 60 forming an upstream space S1 to which blow-by gas is supplied, and an external space S2 of the main body when the pressure of the blow-by gas in the upstream space S1 exceeds a predetermined value. A valve 70 that forms a first flow path C1 and increases the opening degree of the first flow path C1 as the pressure of the blow-by gas in the upstream space S1 is higher; The collection structure 50 has a second flow path C2 with a constant opening degree that communicates with the space S2, and collects mist-like gas from the blow-by gas that has passed through the first flow path C1 and the second flow path C2. It further includes a collector 80 that collects oil.

When the flow rate of the blow-by gas fluctuates while the valve is open, the degree of opening of the valve fluctuates, causing the valve to repeat reciprocating motion. Pulsations occur in the blow-by gas due to the reciprocating movement of the valve. When the frequency of this pulsation matches the resonant frequency of piping such as a breather pipe through which blow-by gas flows, the piping resonates and generates loud noise. However, according to the above configuration, the blow-by gas flows from the upstream space S1 to the external space S2 through the first flow path C1 and the second flow path C2 when the valve is open. Therefore, when the same flow rate of blow-by gas flows into the upstream space S1, the opening degree of the valve 70 (the opening degree of the first passage C1) is smaller than that of a valve that does not have the second passage C2. Become. In other words, the amount of movement of the valve body of the valve 70 is smaller than that of a valve that does not have the second flow path C2. Therefore, the magnitude of the pulsation of the blow-by gas due to the reciprocating movement of the valve 70 is reduced, and the magnitude of the sound generated when the pulsation causes the piping through which the blow-by gas flows to resonate can be suppressed.

In addition, when the valve 70 is open, the distance between the valve body (valve body 71) and the valve seat (the upper end opening of the small diameter cylindrical portion 62) is such that when blow-by gas of the same flow rate flows into the valve, shorter than a valve without. Therefore, the volume of the sound generated when the valve body collides with the valve seat when the valve 70 closes can be reduced.

In addition, in the oil separator 2 of this embodiment, since the valve 70 is provided with the second flow path C2, the pressure of the blow-by gas in the upstream space S1 is reduced depending on the pressure of the blow-by gas in the upstream space S1. It is difficult to rise compared to when there is no such thing. Therefore, the frequency with which the valve 70 opens becomes low. When the valve 70 is closed, no pulsation occurs in the blow-by gas as the valve 70 reciprocates. Therefore, the frequency at which the pulsation of the blow-by gas causes the piping through which the blow-by gas flows to resonate and generate sound becomes low. Further, when the valve 70 is closed, the valve body (valve body 71) does not collide with the valve seat (the upper end opening of the small diameter cylindrical portion 62). Therefore, the frequency at which the valve body collides with the valve seat and generates noise when the valve 70 closes becomes low.

In conventional oil separators, when the flow rate of blow-by gas changes when the valve is open, the force acting on the valve body changes due to the pressure of the blow-by gas, and if the force becomes uneven, , the valve body of the valve may be tilted relative to the main body. When the valve body of the valve is tilted, the direction of the flow of blow-by gas passing between the valve body and the main body of the valve is disturbed, so that the flow rate of the blow-by gas decreases. As a result, the force with which the blow-by gas collides with the collector is weakened, and the performance of the collector (ie, the ability to collect oil mist from the blow-by gas) may be reduced. On the other hand, in the oil separator 2 according to the present embodiment, as described above, since the valve 70 is opened less frequently, when the valve 70 is open, the flow rate of the blow-by gas fluctuates and the valve 70 is tilted. The frequency of occurrence becomes lower. In other words, the frequency with which the performance of the collector 80 deteriorates becomes lower.

Further, in the oil separator 2 according to the present embodiment, the second flow path C2 is provided in the valve 70, as described above. Therefore, even if the flow rate of the blow-by gas fluctuates when the valve 70 is open, a portion of the blow-by gas passes through the second flow path C2, so fluctuations in the pressure of the blow-by gas in the upstream space S1 are reduced. . That is, when the flow rate of the blow-by gas changes, the variation in the magnitude of the force acting on the valve body 71 becomes smaller. As a result, even if the forces acting on the valve body 71 become uneven, the difference in the magnitude of the forces acting on the valve body 71 becomes small, so the flow rate of blow-by gas fluctuates when the valve 70 is open. Even if the valve body 71 is tilted, the valve body 71 becomes difficult to tilt. In other words, the flow of blow-by gas passing through the first flow path C1 is less likely to be disturbed. Therefore, even if the flow rate of the blow-by gas fluctuates when the valve 70 is open, the flow rate of the blow-by gas passing through the first channel C1 is unlikely to decrease, so the performance of the collector 80 is unlikely to decrease.

Furthermore, since the second flow path C2 of this embodiment is provided in the valve 70, parts other than the valve 70 must be changed when changing the size of the second flow path C2 due to a design change. There's no need. Therefore, the size of the second flow path C2 can be easily changed.

Further, the valve 70 of the oil separator 2 according to the present embodiment has a valve elastic body 72 that comes into contact with the main body 60 when the pressure of the blow-by gas in the upstream space S1 is below a predetermined value, and When the pressure exceeds a predetermined value, the valve elastic body 72 and the main body portion 60 are separated to form a first flow path C1.

If the blow-by gas leaks from between the valve body and the valve seat when the valve is closed, the flow rate of the blow-by gas flowing toward the collector through the second flow path C2 will decrease, so the flow rate of the blow-by gas will decrease. descend. As a result, the force with which the blow-by gas collides with the collector is weakened, and the performance of the collector deteriorates. However, according to the above configuration, when the valve 70 closes, the valve elastic body 72 that contacts the upper end of the small diameter cylindrical part 62 of the main body part 60 is deformed along the shape of the upper end of the small diameter cylindrical part 62, and the valve body A gap is unlikely to occur between 71 and the upper end of the small diameter cylindrical portion 62. In other words, since the first flow path C1 is reliably closed, the blow-by gas flowing into the upstream space S1 passes through the second flow path C2 toward the collector 80 without leaking from the first flow path C1. flows. Therefore, when the valve 70 is closed, the flow rate of the blow-by gas flowing toward the collector 80 through the second channel C2 does not decrease, so the performance of the collector 80 does not deteriorate.

In addition, the valve body and the valve seat come into contact with each other with fine dust contained in the blow-by gas adhering to them when the valve is closed, making them susceptible to deformation and wear. However, according to the above configuration, when the valve 70 closes, minute dust contained in the blow-by gas is buried in the valve elastic body 72, so that the valve body (valve body 71) and the valve seat (the upper end of the small diameter cylindrical portion 62) is not deformed. Therefore, the valve body and valve seat are less likely to wear out. As a result, the life of the oil separator 2 is extended.

Furthermore, the valve elastic body 72 collides with the main body portion 60 when the valve 70 closes. At this time, since the valve elastic body 72 deforms to reduce the impact of the collision, the magnitude of the tapping sound generated by the collision between the valve body and the valve seat when the valve 70 closes becomes smaller.

Further, the valve 70 of the oil separator 2 according to the present embodiment further includes a cylindrical portion 73 that projects so as to enter the upstream space S1.

As described above, in conventional oil separators, if the flow rate of blow-by gas fluctuates while the valve is open, the valve body of the valve may become tilted, and the performance of the collector may deteriorate. In contrast, in this embodiment, the cylindrical portion 73 acts as a weight that lowers 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 On the other hand, it becomes difficult to tilt. As a result, even if the flow rate of the blowby gas flowing into the oil separator 2 fluctuates, the flow direction of the blowby gas passing through the first flow path C1 is less likely to be disturbed, so the flow rate of the blowby gas is less likely to decrease. Therefore, the performance of the collector 80 is unlikely to deteriorate.

Further, the oil separator 2 according to the present embodiment includes a lower case 21 and an upper case 22 in which the cases 20 engage with each other, and a plate spring that generates a repulsive force between the lower case 21 and the upper case 22. 120.

In general, case parts that engage with each other are difficult to assemble with high precision due to variations in dimensions. Therefore, processes such as welding and gluing are required to assemble the case parts. In contrast, according to the above configuration, even if the dimensions of the lower case 21 and the upper case 22 vary, the variation in dimensions can be absorbed by the repulsive force generated by the leaf spring 120. Therefore, the lower case 21 and the upper case 22 can be assembled with high accuracy without using construction methods such as welding or adhesion.

Furthermore, construction methods such as welding and gluing require jigs that match the shape of the case. Therefore, when the shape of the case changes due to a design change, a new jig is required to match the shape of the case. On the other hand, according to the above configuration, no jig is required when assembling the oil separator 2, so the cost required when changing the shape of the case 20 can be suppressed.

<Modified example>
You may apply the changes described below in combination.

(1) Modification example 1
In the embodiment described above, the oil separator 2 was attached so as to be embedded in the upper part of the head cover 5 of the engine 4. On the other hand, the oil separator may be attached to the engine body via a bracket or the like. For example, as shown in FIG. 17, the oil separator 202 is attached to the main body of the engine 4 via a bracket (not shown) or the like. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Further, the oil separator 202 may be fixed not to the main body of the engine 4 but to a component other than the engine 4, a vehicle body frame, etc. via a bracket or the like.

Oil separator 202 is a component of ventilation system 201. The ventilation system 201 includes an oil separator 202, a gas supply pipe 203, an oil flow path 204, and a breather pipe 3. Gas supply pipe 203 supplies blow-by gas discharged from the crankcase of engine 4 to oil separator 202 . The oil flow path 204 returns the oil separated by the oil separator 202 to the engine 4.

Oil separator 202 has a case 220 instead of case 20. Case 220 includes a lower case 221 and an upper case 22. The upper case 22 has the same configuration as the oil separator 2, so a description thereof will be omitted.

The lower case 221 is a cylindrical member in the shape of an inverted truncated cone with an open upper end. The lower case 221 has an inflow port 223, an oil discharge port 224, an opening 25, a claw 26, and a cylindrical body 227 (see FIG. 18). Note that the opening portion 25 and the claw portion 26 have the same configuration as the lower case 21, so a description thereof will be omitted.

The inflow port 223 is a portion for allowing blow-by gas to flow into the interior of the oil separator 202. The inflow port 223 according to this modification has a cylindrical shape. One inflow port 223 is provided on the outer peripheral side surface of the lower case 221 so as to protrude radially outward. The internal space of the inflow port 223 communicates with the internal space of the lower case 221. The gas supply pipe 203 is connected to the inflow port 223 .

The oil discharge port 224 is a part for draining the oil separated from the blow-by gas to the outside of the oil separator 202. The oil discharge port 224 according to this modification has a cylindrical shape. One oil discharge port 224 is provided at the lower end of lower case 221. The internal space of the oil discharge port 224 communicates with the internal space of the lower case 221. The oil flow path 204 is connected to the oil discharge port 224 .

The cylindrical body 227 is a part for attaching the oil separator 202 to the engine 4. The cylindrical body 227 is a cylindrical portion that protrudes from the outer peripheral side surface of the lower case 221. The position and number of the cylindrical bodies 227 are not particularly limited as long as the oil separator 202 can be attached to the main body of the engine 4. In this modification, a total of six cylindrical bodies 227 are provided, four on the outer circumferential surface near the upper end of lower case 221 and two on the outer circumferential surface near the lower end.

A mounting hole 227a is provided at the tip of the cylindrical body 227. The attachment hole 227a is a part for attaching a fastening member such as a bolt. One attachment hole 227a is provided for each columnar body 227. A bracket (not shown) is attached to the attachment hole 227a via a bolt.

(2) Modification 2
In the embodiments described above, ventilation system 1 and ventilation system 201 were closed crankcase ventilation systems. However, the ventilation system 1 and the ventilation system 201 may be open crankcase ventilation systems in which the breather pipe 3 is not connected to the intake flow path 6. In this case, the blow-by gas discharged from the oil separator 2 and the oil separator 202 after oil removal is released to the atmosphere.

(3) Modification example 3
In the embodiment described above, the oil separator 2 includes a leaf spring 120 and is composed of a lower case 21 and an upper case 22, in which the cases 20 engage with each other. However, the oil separator 2 may be assembled by bonding or welding without the leaf spring 120.

(4) Modification example 4
In the embodiment described above, the valve body 71 has the valve elastic body 72. However, the valve body 71 may have a structure without the valve elastic body 72.

2,202...Oil separator
20...Case 21, 221...Lower case (first case)
22... Upper case (second case)
50... Collection structure
60...Body part
70...Valve
72...Valve elastic body
73...Cylindrical part
80... Collection body 120... Leaf spring (assembled elastic body)
C1...first flow path
C2...Second flow path
S1...upstream space
S2...External space

Claims (4)

a collection structure that collects the mist-like oil from gas containing the mist-like oil;
a case having an internal space for accommodating the collection structure;
An oil separator comprising:
The collection structure is
a main body portion forming an upstream space to which the gas is supplied;
When the pressure of the gas in the upstream space exceeds a predetermined value, a first flow path is formed that communicates the upstream space with the external space of the main body, and the opening degree of the first flow path is adjusted to a valve that increases as the pressure of the gas in the upstream space increases;
Equipped with
The valve has a second flow path with a constant opening degree that communicates the upstream space and the external space,
The collection structure is an oil separator further including a collection body that collects the mist-like oil from the gas that has passed through the first and second flow paths. The valve includes an elastic body that comes into contact with the main body when the pressure of the gas in the upstream space is below a predetermined value, and when the pressure of the gas in the upstream space exceeds a predetermined value, the elastic body contacts the main body. The oil separator according to claim 1, wherein the first flow path is formed apart from the main body. The oil separator according to claim 1, wherein the valve further has a cylindrical portion that projects so as to enter the upstream space. The 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.

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