WO2020071251A1

WO2020071251A1 - Air breather

Info

Publication number: WO2020071251A1
Application number: PCT/JP2019/037999
Authority: WO
Inventors: 潤一坪田
Original assignee: 株式会社椿本チエイン
Priority date: 2018-10-02
Filing date: 2019-09-26
Publication date: 2020-04-09
Also published as: JP6648796B1; JP2020056460A

Abstract

An air breather (11) is provided with an air flow passage forming portion inside which an air flow passage (28) is formed. The air breather (11) adopts a state of being attached to a housing (13) by a distal end portion of the air flow passage forming portion being inserted into a hole (15) formed in a ceiling wall portion (14) of the housing (13), in such a way as to protrude into the housing (13). The air flow passage (28) includes first opening portions (25) positioned at one end thereof, and a plurality of second opening portions (26) positioned at the other end thereof. In a state in which the air breather (11) is attached to the housing (13), the first opening portions (25) open outside the housing (13). In a state in which the air breather (11) is attached to the housing (13), the plurality of second opening portions (26) open inside the housing (13) in a plurality of locations in a side surface of a distal end portion of the air flow passage forming portion, the plurality of locations being offset in a circumferential direction relative to a central axis (P) of the hole (15), in such a way as to permit the passage of gas and not to permit the passage of liquid.

Description

Air breather

The present disclosure relates to an air breather that is attached to a housing and discharges the internal pressure of the housing to the outside.

エア As a conventional air breather, for example, an air breather described in Patent Document 1 is known. The air breather includes a breather cap and a breather tube having a distal end and a proximal end. The proximal end of the breather tube is connected to the breather cap. When the air breather is attached to the housing, the breather cap is located outside the housing, and the distal end of the breather tube projects into the housing. At the base end of the breather tube, a screw portion is formed which is screwed into a screw hole in a ceiling wall of the housing when the air breather is mounted on the housing. In addition, an air flow path is formed inside the breather cap and the breather tube. The first opening located at one end of the air flow path opens to the surface of the breather cap outside the housing. The second opening located at the other end of the air flow path opens at the side of the distal end of the breather tube in the housing. When the internal pressure of the housing increases in a state where the air breather is attached to the housing, the internal pressure of the housing is released to the outside of the housing through an air flow passage penetrating the breather cap and the breather tube.

JP 2011-179540 A

By the way, when the power mechanism is housed in the housing, a liquid such as lubricating oil may be scattered in the housing as the power mechanism is driven. When the liquid thus scattered falls on the tip of the breather tube projecting into the housing, the splashed liquid flows through the air passage from the second opening opening on the side surface of the tip of the breather tube. There is a possibility that the gas enters the inside and leaks out of the housing through the air flow path. Here, if the direction of the second opening is deviated from the direction in which the liquid is scattered in the housing in a state where the air breather is attached to the housing, the liquid scattered in such a manner is transmitted to the second passage in the air flow path. It is possible to suppress entry into the air flow path from the opening.

However, the threaded state of the threaded portion of the breather tube with respect to the screw hole of the housing is adjusted so that the direction of the second opening, which is open on the side surface of the tip portion of the breather tube, deviates from the direction in which the liquid is scattered in the housing. It is not easy to attach the air breather to the housing while adjusting. Therefore, in the air breather of Patent Document 1, the liquid scattered in the housing may still enter the air flow path from the second opening of the breather pipe, and the liquid leaks out of the housing via the air flow path. It may not be possible to suppress this.

目的 An object of the present disclosure is to provide an air breather that can easily suppress the liquid scattered in a casing from leaking out of the casing.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
An air breather that solves the above-mentioned problem is an air breather including an air flow path forming portion in which an air flow path is formed, and a tip portion of the air flow forming portion is formed in a hole formed in a wall of a housing. By being inserted so as to protrude into the housing, the air breather is attached to the housing, and the air flow path has a first opening located at one end thereof and a plurality of air breathers located at the other end thereof. A state where the air breather is attached to the housing, the first opening is open outside the housing, and the air breather is attached to the housing. In the above, the plurality of second openings are provided at a plurality of locations in the housing, the positions of which are shifted in a circumferential direction with respect to a center axis of the hole on a side surface of the distal end portion of the air flow path forming portion, so that the gas flows therethrough. Passing is allowed Passage of liquid in the way is opened in a manner that does not allow.

According to this configuration, the second opening, which is open on the side surface of the distal end portion of the air flow path forming portion, allows the passage of gas but does not allow the passage of liquid. Therefore, even if the liquid scattered in the housing is applied to the side surface of the distal end of the air flow path forming portion projecting into the housing, it is possible to suppress the liquid from entering the air flow path from the second opening. Therefore, the liquid scattered in the housing does not leak out of the housing via the air flow path. In addition, the liquid scattered from one direction in the housing adheres to the inner surface of the second opening facing the one direction among the plurality of second openings opening on the side surface of the tip of the air flow path forming portion. Even if the air permeability of the second opening may be impaired, no liquid is applied to the second opening facing the other direction. Therefore, the air permeability of the second opening facing in a direction different from the one direction in which the liquid scatters is secured. Therefore, when the internal pressure of the housing increases, the function as an air breather that discharges the internal pressure of the housing to the outside of the housing through the air flow path can be favorably maintained.

In the air breather, the air flow path forming portion has a cylindrical member, the air flow path is formed inside the cylindrical member, and the plurality of second openings are formed in the cylindrical member. Is formed, and at least a portion of the tubular member where the plurality of second openings are formed is covered with a covering member made of a material that allows gas to pass but does not allow liquid to pass. Is preferred.

According to this configuration, the air flow path forming portion having both air permeability and liquid impermeability can be easily configured.
In the air breather, it is preferable that the covering member has liquid repellency.

According to this configuration, when the liquid scattered in the housing is applied to the surface of the covering member, the liquid is more likely to drip along the surface of the covering member than when the covering member does not have liquid repellency. In addition, the liquid can hardly adhere to the surface of the covering member.

In the air breather, it is preferable that a non-arc portion having a non-circular cross section be provided between the second openings adjacent to each other in the circumferential direction.

When the cross-sectional shape of the cylindrical member in which the plurality of second openings are formed in the air flow path forming portion in the circumferential direction is circular, the liquid flows from one direction to the side surface of the tip of the air flow path forming portion in the housing. When scattered, the liquid adhering to the one-way side portion of the side surface of the air flow path forming portion goes around to the portion opposite to the one-way side, and the second opening located at the opposite side portion There is a possibility that the air permeability of the part may be impaired. In this regard, according to the configuration described above, the non-circular portion that can suppress the liquid from flowing around is provided between the second openings adjacent to each other in the circumferential direction on the side surface of the cylindrical member. The liquid adhering to the one-way portion on the side surface of the forming portion may flow to the portion on the opposite side to the one-direction side, and impair the air permeability of the second opening located on the opposite portion. Can be reduced.

In the air breather, the air flow path forming section includes a porous member inserted into the hole such that a tip end protrudes into the housing, and at least a part of the air flow path is formed in the porous member. It is preferable that it is constituted by an infinite number of pores formed so as to allow gas to pass therethrough but not allow liquid to pass therethrough.

According to this configuration, the air flow path forming portion having both air permeability and liquid impermeability can be easily configured by using a porous member having countless pores constituting at least a part of the air flow path. .

According to the present disclosure, it is possible to easily suppress the liquid scattered in the casing from leaking out of the casing.

FIG. 2 is a partially cutaway front view of the housing to which the air breather of one embodiment is attached. FIG. 2 is a front sectional view showing a schematic configuration of the air breather of FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2; FIG. 6 is a cross-sectional plan view of an air breather according to a first modification. FIG. 13 is a plan sectional view of an air breather according to a second modification. FIG. 13 is a plan sectional view of an air breather according to a third modification. The front sectional view of the air breather of a 4th modification.

Hereinafter, an air breather 11 according to an embodiment will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the air breather 11 is attached to a housing 13 that houses a power mechanism 12 therein. Specifically, a female screw hole (hole) 15 is formed in the ceiling wall portion 14 of the housing 13. Then, the air breather 11 is inserted into the female screw hole 15 so that the tip end projects into the housing 13 and is attached to the housing 13. The housing 13 is a structure whose inside is closed. When the internal pressure of the housing 13 increases due to heat generation at the time of driving the power mechanism 12, the internal pressure is released to the outside of the housing 13 via the air breather 11.

The air breather 11 includes a cap member 16, a tubular member 17, a bag-shaped covering member 18, and an O-ring 19 having a sealing function. The cap member 16 has a shaft 21 and a knob 22. On the peripheral surface of the shaft portion 21, a male screw portion 20 that can be screwed into the female screw hole 15 of the housing 13 is formed. The knob 22 is formed at the base end (the upper end in FIG. 2) of the shaft 21 so as to form a flange having a larger diameter than the shaft 21.

The cap member 16 has the knob portion 22 located outside the housing 13 in a state where the male screw portion 20 of the shaft portion 21 is screwed into the female screw hole 15 of the ceiling wall portion 14 of the housing 13. Inside the shaft portion 21, a concave portion 23 extending from the distal end surface of the shaft portion 21 toward the base end of the shaft portion 21 and having a circular cross-sectional shape is formed. Inside the knob 22, an in-cap passage 24 is formed. A first opening 25 located at one end of the in-cap passage 24 is open on the outer peripheral surface of the knob 22. The second opening located at the other end of the in-cap passage 24 is open at the inner bottom surface of the recess 23. That is, the first opening 25 of the in-cap passage 24 opens outside the housing 13 in a state where the male screw portion 20 of the shaft portion 21 is screwed into the female screw hole 15 of the ceiling wall portion 14.

及び As shown in FIGS. 2 and 3, the cylindrical member 17 is a resin member having a cylindrical shape with a bottom, such as a test tube. At least one slit (not shown) is formed at one end (the upper end in FIG. 2) of the cylindrical member 17 so as to extend along the axial direction. That is, the cylindrical member 17 can be inserted into the concave portion 23 of the shaft portion 21 of the cap member 16 in a state where the one end portion where the slit is formed is elastically deformed so as to reduce the inner diameter. Then, as shown in FIG. 2, the cylindrical member 17 has one end inserted into the recess 23 of the shaft 21 of the cap member 16 and the outer peripheral surface of the one end adhered to the inner peripheral surface of the recess 23. Then, it is integrated with the cap member 16.

As shown in FIG. 2, one end of the cylindrical member 17 is inserted into the concave portion 23 of the shaft portion 21 of the cap member 16 in a state where the male screw portion 20 of the shaft portion 21 is screwed into the female screw hole 15 of the ceiling wall portion 14. When the base end, which is the upper end in FIG. 2, is inserted, the other end of the tubular member 17 (the distal end, which is the lower end in FIG. 2) projects into the housing 13. A plurality of rectangular second openings 26 that are long in the axial direction are formed in the portion of the cylindrical member 17 protruding into the housing 13 on the distal end side in the axial direction.

That is, the cylindrical member 17 is aligned in the axial direction with the center axis P of the cylindrical member 17 aligned with the center axis P of the female screw hole 15 into which the male screw portion 20 of the shaft portion 21 of the cap member 16 is screwed. As a result, the portion on the tip end side protrudes into the housing 13. Then, the inside and outside of the tubular member 17 are communicated with each other at a plurality of positions on the side surface on the tip end side of the tubular member 17 which are shifted in the circumferential direction with respect to the central axis P of the tubular member 17. A plurality of rectangular second openings 26 are formed. In the present embodiment, vertically elongated second openings 26 are formed at four positions shifted by 90 degrees in the circumferential direction with respect to the center axis P of the cylindrical member 17.

In this case, a pipe flow path 27 is formed inside the tubular member 17 to allow the gas flowing through the plurality of second openings 26 to flow therethrough. The pipe flow path 27 in the tubular member 17, the cap flow path 24 in the knob 22 of the cap member 16, and the recess 23 in the shaft 21 of the cap member 16 form one end. An air flow path 28 is formed in which the first opening 25 located opens outside the housing 13 and the second opening 26 located at the other end opens inside the housing 13. In the present embodiment, the cap member 16 in which the in-cap passage 24 and the concave portion 23 which form a part of the air flow path 28 are formed, and also a part of the air flow path 28 are formed. An air flow path forming section in which an air flow path 28 is formed is constituted by the tubular member 17 in which the pipe flow path 27 is formed.

As shown in FIG. 2, the covering member 18 covers the entirety of the cylindrical member 17 including the second opening 26 from the distal end side of the cylindrical member 17. It is a bag body. Then, as shown in FIG. 2, the covering member 18 is positioned on the opposite side in the height direction from the bottom portion 29 in a state where the covering member 18 is covered by the tubular member 17 so as to cover the entire tubular member 17 from below. The open end (upper end in FIG. 2) is inserted into the concave portion 23 of the shaft portion 21 of the cap member 16 together with the base end of the tubular member 17.

The cover member 18 is made of, for example, a fluororesin porous film having oil repellency (liquid repellency in a broad sense). The covering member 18 functions as a highly functional membrane having gas permeability and liquid impermeability that allows gas to pass but does not permit liquid to pass. Therefore, gas flows from the inside of the housing 13 into the air flow passage 28 through the second opening 26 formed at the distal end portion of the cylindrical member 17 in the air flow passage 28 and opening into the housing 13. Even if it is present, liquid lubricating oil or water does not flow in.

Next, the operation of the air breather 11 configured as described above will be described.
Now, as shown in FIG. 1, when the power mechanism 12 housed in the housing 13 rotates in the direction indicated by the solid arrow at the time of driving, the lubricating oil of the power mechanism 12 in the direction indicated by the white arrow in the housing 13. Scatters. Then, as shown in FIG. 3, the lubricating oil scattered from one direction indicated by a white arrow is applied to the side surface of the distal end of the cylindrical member 17 protruding into the housing 13 of the air breather 11, and the cylindrical member 17 17 extends over the covering member 18 covering the side surface of the distal end portion 17.

Here, as shown in FIG. 3, the direction of the second opening 26 opening on the side surface of the distal end portion of the cylindrical member 17 protruding into the housing 13 is indicated by a white arrow through which the lubricating oil of the power mechanism 12 scatters. If the second opening 26 of the cylindrical member 17 is not covered with the covering member 18 in the case where the lubricating oil is directed in the direction 28. Then, there is a possibility that the lubricating oil leaks out of the housing 13 through the first opening 25 that opens out of the housing 13 of the air flow path 28.

However, in the present embodiment, the gas permeability and the non-liquid passage not permitting the passage of the liquid while permitting the passage of the gas including the portion where the side surface of the distal end portion of the cylindrical member 17 has the second opening 26 are allowed. It is covered with a covering member 18 which is a highly functional film having a property. That is, the second opening 26 that opens on the side surface of the distal end portion of the cylindrical member 17 is covered with the covering member 18, so that gas is allowed to pass while liquid is not allowed to pass. Therefore, even if the direction of the second opening 26 is oriented in the direction indicated by the outline arrow where the lubricating oil of the power mechanism 12 is scattered, the lubricating oil enters the air flow path 28 through the second opening 26. Penetration is suppressed by the covering member 18.

Further, as shown in FIG. 3, the lubricating oil scattered from one direction indicated by a white arrow adheres to the surface of the covering member 18 covering the side surface of the distal end portion of the cylindrical member 17, and the lubricating oil adheres. When the film 30 is formed, the air permeability of the covering member 18 is hindered by the adhered film 30. However, in this case, the air permeability of the surface of the covering member 18 due to the adhesion film 30 of the lubricating oil is hindered only in a part of the lubricating oil, which is scattered in the direction indicated by the white arrow. In other words, the portion where such an adhesion film 30 is formed is shifted by a predetermined angle or more (for example, 90 degrees or more) in the circumferential direction with respect to the central axis P of the cylindrical member 17 and is indicated by a white arrow. Since the lubricating oil scattered from one direction does not adhere, the air permeability in such a displaced portion is ensured.

In other words, of the plurality of second openings 26 that are opened on the side surface of the distal end portion of the cylindrical member 17, the second opening 26 that faces in a direction different from the one direction indicated by the outlined arrow in which the lubricating oil scatters in the housing 13. In the second opening 26, the portion of the covering member 18 that covers the second opening 26 is not hindered by the lubricating oil adhesion film 30 from impairing air permeability. Therefore, the air breather 11 has a second opening 26 facing in a direction different from the one direction indicated by a white arrow in which the lubricating oil scatters inside the housing 13 and a first opening opening outside the housing 13. The internal pressure of the housing 13 can be released to the outside of the housing 13 through the portion 25 and an air flow path 28 connecting between the first opening 25 and the second opening 26.

Further, since the covering member 18 covering the cylindrical member 17 has oil repellency, even if the lubricating oil scattered in the housing 13 is applied to the surface of the covering member 18, the lubricating oil is applied to the covering member 18. 18 hangs down along the surface. Furthermore, when the air breather 11 is attached to the housing 13, the side surface of the distal end of the cylindrical member 17 protruding into the housing 13 is displaced in the circumferential direction with respect to the center axis P of the cylindrical member 17. Since the second openings 26 are provided at a plurality of locations, it is not necessary to be aware of the direction in which the second openings 26 face when the air breather 11 is attached to the housing 13.

When the existing air breather 11 has deteriorated over time, if the cap member 16 is rotated in a direction in which the screwing state of the male screw portion 20 to the female screw hole 15 is loosened, the mounting state of the air breather 11 to the housing 13 is eliminated. Is done. Then, at least one of the tubular member 17 and the covering member 18 covering the second opening 26 of the tubular member 17 that needs to be replaced is removed, replaced, and then attached to the housing 13 again. Thus, maintenance of the air breather 11 can be easily performed.

According to the above embodiment, the following effects can be obtained.
(1) The second opening 26, which is open on the side surface of the distal end of the cylindrical member 17, is covered with a covering member 18 that allows gas to pass but does not allow liquid to pass. Therefore, even if the lubricating oil (liquid) scattered in the housing 13 is applied to the side surface of the distal end portion of the cylindrical member 17 protruding into the housing 13, the lubricating oil (liquid) is lubricated into the air flow path 28 from the second opening 26. Oil can be prevented from entering. Therefore, the lubricating oil scattered in the casing 13 does not leak out of the casing 13 through the air flow path 28.

(2) The lubricating oil scattered from one direction in the housing 13 is formed on the inner surface of the second opening 26 facing one direction among the plurality of second openings 26 opening on the side surface of the distal end of the tubular member 17. Even if it adheres and impairs the air permeability of the second opening 26, the liquid does not fall on the second opening 26 facing in another direction. Therefore, the air permeability of the second opening 26 facing the direction different from the one direction in which the lubricating oil scatters is secured. Therefore, when the internal pressure of the housing 13 rises, the function of the air breather 11 that discharges the internal pressure of the housing 13 to the outside of the housing 13 through the air flow path 28 can be favorably maintained.

(3) At least a portion of the tubular member 17 where the second opening 26 is formed is covered with a covering member 18 made of a material that allows gas to pass therethrough but does not allow lubricating oil (liquid) to pass therethrough. The air flow path forming part having both the liquid permeability and the liquid impermeability can be easily configured.

(4) The covering member 18 has oil repellency. Therefore, when the lubricating oil scattered in the housing 13 is applied to the surface of the covering member 18, the lubricating oil drips along the surface of the covering member 18 as compared with the case where the covering member 18 does not have oil repellency. The lubricating oil can be easily dropped and the lubricating oil can hardly adhere to the surface of the covering member 18.

The above embodiment may be modified as in the following modification. Further, the configuration included in the embodiment and the configuration included in the following modification may be arbitrarily combined, or the configuration included in the following modification may be arbitrarily combined.

As in the first modified example shown in FIG. 4, the cylindrical member 17 that forms a part of the air flow path forming portion in the air breather 11 has a square cross section orthogonal to the center axis P. It may be 17. That is, in the cylindrical member 17 in this case, the non-circular portion 31 composed of the four corners bent at right angles in the cross-sectional shape is located between the second openings 26 adjacent in the circumferential direction. I have.

Here, if the cross-sectional shape of the cylindrical member 17 in which the plurality of second openings 26 are formed in the circumferential direction is circular, the lubricating oil flows in one direction to the side surface of the distal end portion of the cylindrical member 17 in the housing 13. When scattered from the lubricating oil, the lubricating oil adhering to the one-way side portion of the side surface of the cylindrical member 17 spills to a portion opposite to the one-direction side, and the second opening located at the opposite side portion There is a possibility that air permeability of the portion 26 may be impaired.

In this regard, according to the configuration of the first modified example, the non-circular portion 31 that can suppress the spill of lubricating oil is provided between the second openings 26 that are adjacent in the circumferential direction on the side surface of the cylindrical member 17. Is provided. Therefore, the lubricating oil scattered from one side indicated by a white arrow in FIG. 4 to the side surface of the cylindrical member 17 of the first modified example is indicated by a two-dot chain line at the non-circular portion 31 on the side surface of the cylindrical member 17. It is guided in a direction away from the side surface of the cylindrical member 17 as shown by a white arrow. Therefore, the lubricating oil scattered from the one side with respect to the side surface of the cylindrical member 17 flows around to the part on the opposite side to the one side, and the ventilation of the second opening 26 located on the opposite side is performed. This can reduce the risk of impairing the performance.

As in the second modified example shown in FIG. 5, the cylindrical member 17 that forms a part of the air flow path forming portion in the air breather 11 has an outer shape of a cross section orthogonal to the center axis P other than a square such as a hexagon. The cylindrical member 17 may be a polygon. That is, the cylindrical member 17 is provided between the second openings 26 adjacent to each other in the circumferential direction with the non-circular portions 31 each having a corner portion bent at an angle other than a right angle in the cross-sectional shape. Also in this case, the lubricating oil scattered from the one side indicated by the white arrow in FIG. 5 to the side surface of the cylindrical member 17 of the second modified example is located at the non-arc portion 31 on the side surface of the cylindrical member 17. It is guided in a direction away from the side surface of the cylindrical member 17 as shown by a hollow arrow of a chain line. Therefore, the lubricating oil scattered from the one side with respect to the side surface of the cylindrical member 17 flows around to the part on the opposite side to the one side, and the ventilation of the second opening 26 located on the opposite side is performed. This can reduce the risk of impairing the performance.

-Like the third modification shown in FIG. 6, the outer peripheral surface of the cylindrical member 17 having a circular cross-sectional shape, and protrudes radially between the second openings 26 adjacent in the circumferential direction. A non-circular portion 31 constituted by a convex portion may be provided. Also in this case, the lubricating oil scattered from the one side indicated by the white arrow in FIG. 6 to the side surface of the cylindrical member 17 of the third modified example is such that the non-circular portion 31 on the side surface of the cylindrical member 17 is radially outward. At the portion protruding toward the side, the wraparound to the part on the opposite side to the one direction side is regulated, and the risk of impairing the air permeability of the second opening 26 located at the part on the opposite side can be reduced.

As in the fourth modified example shown in FIG. 7, instead of the cylindrical member 17 and the covering member 18 in the air breather 11 of the above embodiment, the distal end portion is formed in the female screw hole 15 of the ceiling wall portion 14 of the housing 13. The air flow path forming portion may be configured by using a porous member 32 such as a porous ceramic or the like inserted so as to protrude into the inside 13. In this case, the porous member 32 is formed in a column shape, and the base end thereof is inserted into the concave portion 23 of the shaft portion 21 of the cap member 16. The porous member 32 is formed with innumerable fine pores 33 so as to allow passage of gas but not passage of liquid. A part of the air flow path 28 is constituted by the countless minute pores 33. According to the configuration of the fourth modified example, the air flow path forming portion having both air permeability and liquid impermeability is formed by using the porous member 32 through which the innumerable pores 33 functioning as the air flow path 28 are formed. It can be easily configured.

In the fourth modified example, a male screw portion that is screwed into the female screw hole 15 of the housing 13 is provided at the base end of the porous member 32, and when the male screw portion is screwed into the female screw hole 15, the porous member The surface of the base end of the projection 32 may be exposed outside the housing 13. In this case, the internal pressure of the casing 13 is increased through the innumerable pores 33 formed through the porous member 32 so as to form an air flow path 28 from the base end to the tip end of the porous member 32. Released outside.

The cylindrical member 17 in which the non-circular portion 31 is provided between the second openings 26 adjacent to each other in the circumferential direction shown in the first modification to the third modification has a square outer shape in cross section. In addition, if the outer shape is non-circular and the outer peripheral surface is a non-cylindrical surface, for example, the outer shape of the cross section may be a star shape, or it may be configured by alternating irregularities in the circumferential direction. It may have an outer peripheral surface.

The number of the second openings 26 formed on the side surface of the distal end portion of the cylindrical member 17 is arbitrary, and may be a plurality of three or five other than the four shown in the embodiment, or may be one. Good. That is, even if the number of the second openings 26 is one, a covering member made of a material that allows gas to pass through the cylindrical member 17 but does not allow liquid to pass so as to cover the second openings 26. If the cover 18 is covered, it is possible to suppress the lubricating oil (liquid) scattered in the housing 13 from entering the air flow path 28 through the second opening 26.

-The cylindrical member 17 may be a bottomless cylindrical pipe instead of a bottomed cylindrical shape.
The covering member 18 does not necessarily have to have oil repellency (liquid repellency in a broad sense).
If the covering member 18 has gas permeability and liquid impermeability that allows gas to pass but does not allow liquid to pass, a high-functional film forming material made of a material different from the fluororesin porous film, etc. May be configured.

The covering member 18 may be a sheet attached to the tubular member 17 so as to cover only the portion of the tubular member 17 where the second opening 26 is formed.
Next, technical ideas that can be grasped from the above-described embodiment and modified examples will be described together with their operational effects.

(A) An air breather including an air flow path forming portion having an air flow path formed therein, wherein a tip of the air flow path forming portion projects into the housing through a hole formed in a wall of the housing. The air breather is attached to the housing, and the air flow path has a second opening located at one end thereof and a plurality of second openings located at the other end thereof. In the state where the air breather is attached to the case, the first opening is open outside the case, and in the state where the air breather is attached to the case, An air breather having a second opening that is open at a plurality of locations in the housing that are displaced in a circumferential direction with respect to a center axis of the hole on a side surface of the distal end portion of the air flow path forming portion.

According to the technical idea (A), when the air breather is attached to the housing, it is not necessary to be conscious of the direction in which the second opening on the side surface of the distal end of the tubular member faces in the housing. Then, even when the lubricating oil (liquid) scatters from one direction in the housing, the lubricating oil scattered from the one direction does not reach the second openings directed in other directions than the one direction. Therefore, the air permeability of the air flow path can be ensured via the second opening facing in a direction different from the one direction in which the lubricating oil scatters.

(B) An air breather including an air flow path forming portion having an air flow path formed therein, wherein a tip end of the air flow path forming portion projects into the housing through a hole formed in a wall of the housing. The air breather is attached to the housing by being inserted so that the air flow path has a first opening located at one end thereof and a second opening located at the other end thereof. The first opening is open outside the housing when the air breather is attached to the housing, and the second opening is open when the air breather is attached to the housing. Is an air breather that is open in such a manner as to allow gas to pass therethrough but not allow liquid to pass therethrough.

According to this technical idea (B), even if the liquid scattered in the housing hangs on the side surface of the front end of the air flow path forming portion protruding into the housing, the second side opening on the side surface of the front end. Since the two openings allow the passage of gas but not the passage of liquid, it is possible to suppress the liquid from entering the air flow channel from the second opening. Therefore, the liquid scattered in the housing does not leak out of the housing via the air flow path.

11 ... air breather, 13 ... housing, 14 ... ceiling wall as an example of wall, 15 ... female screw hole as an example of hole, 17 ... tubular member constituting air flow path forming part, 18 ... covering member, 25: first opening, 26: second opening, 31: non-arc portion, 32: porous member, 33: pore, P: central axis.

Claims

An air breather including an air flow path forming portion having an air flow path formed therein,
The air breather is attached to the housing by being inserted into a hole formed in the wall of the housing so that the tip of the air flow path forming portion projects into the housing,
The air flow path has a first opening located at one end thereof, and a plurality of second openings located at the other end thereof.
In a state where the air breather is attached to the housing, the first opening is open outside the housing,
In a state where the air breather is attached to the housing, the plurality of second openings are formed in the housing in a circumferential direction with respect to a center axis of the hole at a side surface of the distal end portion of the air flow path forming portion. An air breather is opened at a plurality of locations shifted in position in such a manner as to permit gas passage but not liquid passage.
The air flow path forming portion has a cylindrical member,
The air flow path is formed inside the tubular member,
The plurality of second openings are formed in the tubular member,
2. The cylindrical member according to claim 1, wherein at least a portion where the plurality of second openings are formed is covered with a covering member made of a material that allows gas to pass but does not allow liquid to pass. Air breather.
The air breather according to claim 2, wherein the covering member has liquid repellency.
4. The air breather according to claim 2, wherein the cylindrical member has a non-arc portion having a non-arc shape in a cross-sectional shape provided between adjacent second openings in the circumferential direction. 5.
The air flow path forming section includes a porous member inserted into the hole so that a tip end protrudes into the housing,
2. The air breather according to claim 1, wherein at least a part of the air flow path is formed by an infinite number of pores formed so as to allow gas to pass through the porous member but not allow liquid to pass therethrough. .