Plug for vehicle

A plug for a vehicle includes: a body portion; a plurality of insertion portions configured to be inserted into a through-hole provided in a housing; and a flange portion having a notch formed on an outer periphery so as to restrict a rotation of the body portion around an axial center. The insertion portions are formed at two positions opposed to each other across a straight line passing through the notch and the axial center and are provided with retaining lugs engageable with the through-hole.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2016-188867 filed on Sep. 27, 2016 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a plug for a vehicle, the plug being inserted into a through-hole provided in a housing.

2. Description of Related Art

There has been well known a plug for a vehicle, including: a body portion having a circular-column outer shape and partially inserted into a through-hole provided in a housing; and a plurality of insertion portions formed integrally at intervals around an axial center of the body portion so as to extend from one end of the body portion in a direction parallel to the axial center, the plurality of insertion portions being inserted into the through-hole. An example thereof is a breather plug described in Japanese Patent Application Publication No. 2008-180313 (JP 2008-180313 A). JP 2008-180313 A discloses a breather device including a breather plug inserted into a through-hole provided in a transmission case, a breather hose connected to the breather plug, and a breather chamber communicating with atmosphere through the breather plug and the breather hose. Here, the plug for the vehicle includes a retaining lug provided in an insertion portion to be inserted into the through-hole so as to prevent the plug from falling out of the through-hole. Various structures are known as such a structure for retaining the plug for the vehicle. For example, there is a structure of a plug described in Japanese Patent Application Publication No. 8-218818 (JP 8-218818 A). JP 8-218818 A discloses a plug including a plurality of locking arms (corresponding to insertion portions) formed at intervals in a circumferential direction so as to be inserted into a through-hole, and retaining hook portions (corresponding to retaining lugs) provided in respective tip ends of the locking arms.

SUMMARY

In the meantime, like the breather device disclosed in JP 2008-180313 A, the hose may be connected to the plug. In such a case, the plug may rotate around its axial center due to application of an external force to the hose, or the like reason. In this regard, it is conceivable that a flange portion having a notch for prevention of rotation on its outer periphery is provided in a part of the plug, the part being not inserted into the through-hole, so that the rotation of the plug around the axial center is restricted by the notch and a projecting member provided in the housing at a position adjacent to the plug so as to project outside the housing. Meanwhile, depending on a configuration of the insertion portion provided with the retaining lug, the plug may easily fall out with respect to an external force applied to the plug. Particularly, in a case of the plug provided with the notch for prevention of rotation, when an external force is applied to the plug so as to incline the plug in an opposite direction to the notch, the plug is easily inclined, so that a hook margin of the retaining lug is reduced, which may cause the plug to easily fall out of the through-hole.

The present disclosure provides a plug for a vehicle, the plug being configured to hardly fall out of a through-hole even if the plug is inclined due to an external force, in a case where a flange portion having a notch for restricting rotation around an axial center is provided.

A plug for a vehicle according to an aspect of the present disclosure includes: a body portion having a circular-column shape and configured such that one part of the body portion is inserted into a through-hole provided in a housing; a plurality of insertion portions formed integrally at intervals around an axial center of the body portion so as to extend from one end of the body portion in a direction parallel to the axial center, the plurality of insertion portions being configured to be inserted into the through-hole; and a flange portion formed integrally with the other part of the body portion, the other part being not inserted into the through-hole, the flange portion having a notch formed on an outer periphery so as to restrict a rotation of the body portion around the axial center by being engaged with a projecting member provided in the housing in a projecting manner toward outside the housing at a position adjacent to the body portion. The insertion portions are formed at two positions opposed to each other across a straight line passing through the notch and the axial center and are provided with retaining lugs engageable with the through-hole.

In the above aspect, the insertion portions are formed at the two positions opposed to each other across the straight line passing through the notch and the axial center and are provided with retaining lugs engageable with the through-hole. Accordingly, when the plug for the vehicle is inclined due to an external force in a direction opposite to the notch in which direction the plug for the vehicle is easily inclined, hook margins of the retaining lugs are hardly reduced. That is, by providing the retaining lugs at the positions where the hook margins of the retaining lugs are not reduced at the time when the plug for the vehicle is inclined due to the external force, it is possible to restrain the plug for the vehicle from falling out. Accordingly, in a case where the plug for the vehicle includes the flange portion provided with the notch that restricts the rotation around the axial center, even if the plug for the vehicle is inclined due to the external force, the plug for the vehicle can hardly fall out of the through-hole.

In the above aspect, the insertion portions may be further formed at two positions opposed to each other across the axial center, on the straight line passing through the notch and the axial center; and the insertion portions formed at the two positions opposed to each other across the axial center may not be provided with the retaining lugs.

Further, in the above configuration, the insertion portions are further formed at the two positions opposed to each other across the axial center, on the straight line passing through the notch and the axial center, which allows the plug for the vehicle to be easily inserted straight into the through-hole at the time when the plug for the vehicle is inserted into the through-hole. Further, since the insertion portions formed at the two positions opposed to each other across the axial center are not provided with the retaining lugs, the plug for the vehicle is easily inserted into the through-hole. That is, when the retaining lugs are provided only at the positions where the hook margins of the retaining lugs are not reduced at the time when the plug for the vehicle is inclined due to the external force, it is possible to achieve both restraint of falling-off of the plug for the vehicle and easiness of the insertion thereof.

In the above aspect, the flange portion may have a sector shape with an arc smaller than a semicircle, and the notch may be formed in the arc.

Further, in the above configuration, the flange portion is configured such that an arc where the notch is formed has a sector shape with an arc smaller than a semicircle, and therefore, it is useful to provide the retaining lugs at positions where the hook margins of the retaining lugs are not reduced at the time when the plug for the vehicle is inclined due to an external force in a direction opposite to the notch in which direction the plug is easily inclined.

In the above aspect, the plug may further include a hose joint portion formed integrally with the other part of the body portion and configured to communicate an external space outside the housing with a hole portion inside the body portion, the hole portion being configured to communicate with a breather chamber provided in an upper part inside the housing. The plug may be a breather plug.

Further, in the above configuration, the plug for the vehicle is a breather plug provided with the hose joint portion, and therefore, in a case where the breather plug includes the flange portion having the notch that restricts the rotation around the axial center, which might occur due to application of an external force to the hose, or the like reason, even if the breather plug is inclined due to the external force, the breather plug can hardly fall out of the through-hole.

DETAILED DESCRIPTION OF EMBODIMENTS

An embodiment of the present disclosure will hereinafter be described in detail with reference to the drawings.

FIG. 1is an outside drawing schematically illustrating a housing10to which a plug20for a vehicle (hereinafter just referred to as the plug20) is attached (see a circled part indicated by an alternate long and short dash line inFIG. 1). The present disclosure is applied to the plug20.FIG. 2is an outside drawing schematically illustrating the plug20.FIG. 3is an outside drawing of the plug20illustrated inFIG. 2, when viewed from A.FIG. 4is an outside drawing of the plug20illustrated inFIG. 2, when viewed from B.FIG. 5is an outside drawing of the plug20illustrated inFIG. 2, when viewed from C.FIG. 6is a sectional view taken along a line D-D in the outside drawing viewed from A inFIG. 3.FIG. 7is a view illustrating a state where the plug20is attached to the housing10, together with the outside drawing ofFIG. 2, the outside drawing viewed from B inFIG. 4, and the outside drawing viewed from C inFIG. 5.

InFIGS. 1 to 7, the housing10is a case (more specifically, a transmission case) in which a power transmission device is accommodated, the power transmission device being provided in a power transmission path between a driving force source such as an engine (and/or a rotating machine) and driving wheels. The plug20is a well-known breather plug attached to a through-hole12(seeFIG. 7) provided on a top surface of the housing10, for example, so as to prevent oil leakage by adjusting a pressure in the housing10. Further, the plug20is a plug made of resin, for example.

The housing10includes a breather chamber14(seeFIG. 7) provided in an upper part (a vehicle upper side) inside the housing10. The breather chamber14communicates with an external space outside the housing10through the plug20. Oil (e.g., oil mist) gathered by a rotational member of the power transmission device placed inside the housing10flows into the breather chamber14, for example. In order that the oil mist and the air do not gush out into the external space outside the housing10, for example, the breather chamber14has a structure (that is, a labyrinth structure) in which a passage is provided in a form of labyrinth by ribs (not shown) as a plurality of partition walls in an upper space inside the housing10near the plug20. That is, in the breather chamber14, it is necessary for the oil entering (flowing) through a breather chamber inlet to pass through the labyrinth-shaped passage so as to reach the through-hole12(the same meaning as the plug20herein), and before the oil reaches the through-hole12, the oil is accumulated in some spaces in the passage due to a viscosity or a surface tension of the oil itself. This appropriately prevents so-called breather blow, which discharges the oil inside the housing10to outside the housing10.

The plug20includes: a body portion22having a circular-column outer shape and configured such that one part22athereof to be inserted into the through-hole12and the other part22bthat is not inserted into the through-hole12are formed integrally (that is, the one part22ais inserted into the through-hole12); and a plurality of insertion portions24formed integrally with the one part22aat predetermined intervals around an axial center Cs of the body portion22so as to extend in a direction parallel to the axial center Cs from one end (an end of the one part22aon an opposite side to the other part22b) of the body portion22, the plurality of insertion portions24being inserted into the through-hole12. The other part22bof the body portion22is configured such that a radius of its section perpendicular to the axial center Cs is larger than the through-hole12having a circular section perpendicular to the axial center Cs. The plug20includes, as the insertion portions24, four insertion portions, i.e., an insertion portion24a, an insertion portion24b, an insertion portion24c, and an insertion portion24d. This allows the plug20to be easily inserted straight into the through-hole12at the time when the plug20is inserted into the through-hole12. A groove22cto which an annular sealing member30(seeFIG. 7) is fitted is formed on an outer periphery of the one part22aof the body portion22. A hole portion22d(seeFIG. 6) communicating with the breather chamber14is formed inside the body portion22. Accordingly, the body portion22has a generally cylindrical shape. Note that the axial center Cs corresponds to an axis (a rotating axis) when the body portion22is assumed a circular column.

The plug20further includes a hollowed hose joint portion26formed integrally with the other part22bof the body portion22. Inside the hose joint portion26, a joint hole portion26ais formed so as to communicate with the hole portion22din the body portion22on one end side thereof and communicate with the external space outside the housing10on the other end side thereof. Accordingly, the hose joint portion26communicates the hole portion22dinside the body portion22with the external space outside the housing10. A breather hose (not shown), for example, is attached to the hose joint portion26. The breather hose is placed in the external space around the housing10, and the other end thereof opposite to one end thereof attached to the hose joint portion26is opened to the external space outside the housing10. The breather hose is extended upward from the hose joint portion26, and further, the other end thereof is opened downward, so that water, a foreign matter, or the like does not enter the housing10from the other end, for example.

The plug20further includes a flange portion28formed integrally with the other part22bof the body portion22. The flange portion28includes a notch28aon its outer periphery so as to restrict a rotation of the body portion22around the axial center Cs by being engaged with a projecting member16(seeFIG. 7) provided in the housing10in a projecting manner toward outside the housing10at a position adjacent to the body portion22(the other part22b). The flange portion28has a sector shape with an arc smaller than a semicircle (that is, a sector shape with a minor arc, which is a circular arc smaller than the semicircle). The flange portion28has the notch28aformed in the above sector arc shape. To provide the flange portion28with such a notch28ais useful for the plug20to which the breather hose is connected and which may rotate around the axial center Cs due to application of an external force to the breather hose, or the like reason.

Here, the plug20includes a retaining lug25provided in the insertion portion24to be inserted into the through-hole12so as to prevent the plug20from falling out of the through-hole12. That is, the insertion portion24is provided with the retaining lug25that is engageable with the through-hole12. The retaining lug25will be described below in detail.

In the plug20provided with the notch28afor prevention of rotation, when an external force (see a blank arrow inFIG. 7) is applied to the plug20so as to incline the plug20in an opposite direction to the notch28a, the notch28ais hardly caught on the projecting member16, and therefore, the plug20is easily inclined. On that account, in a case where the plug20is provided with the notch28afor prevention of rotation, the plug20most easily falls out of the through-hole12in terms of the external force applied in a direction indicated by the blank arrow inFIG. 7.

In this regard, the insertion portions24provided with the retaining lugs25are formed at two positions opposed to each other across a straight line passing through the notch28a(e.g., a center of the notch28aor near the center of the notch28a) and the axial center Cs.

More specifically, the insertion portions24a,24bare formed at two positions opposed to each other across the straight line passing through the notch28aand the axial center Cs, and are provided with retaining lugs25a,25b.

In a case where the plug20is provided with the notch28afor prevention of rotation, when the retaining lugs25are provided at positions (see parts a, b circled by an alternate long and short dash line inFIG. 7) where the insertion portions24a,24bare formed in terms of the external force applied in the direction indicated by the blank arrow ofFIG. 7, the retaining lugs25are always caught on the through-hole12, thereby making it difficult for the plug20from falling out. In a case where the plug20is provided with only two retaining lugs25, it is useful to provide the retaining lugs25at the positions of the parts a, b circled by the alternate long and short dash line inFIG. 7. Further, in a case where the plug20is provided with only two retaining lugs25, the plug20is easily inserted into the through-hole12in comparison with a case where all the insertion portions24are provided with respective retaining lugs25.

Meanwhile, the insertion portions24c,24dare formed at two positions opposed to each other across the axial center Cs on the straight line passing through the notch28aand the axial center Cs, and no retaining lug25is provided in the insertion portions24c,24d. In a case where two retaining lugs25are provided only at positions (that is, positions of parts c, d circled by an alternate long and short dash line inFIG. 7) where the insertion portions24c,24dare formed, if an external force is applied in the direction indicated by the blank arrow inFIG. 7, the retaining lug25provided in the insertion portion24dmoves in a direction apart from the through-hole12due to the principle of leverage, so that the plug20easily falls out.

As described above, in the present embodiment, the insertion portions24(the insertion portions24a,24b) are formed at two positions opposed to each other across the straight line passing through the notch28aand the axial center Cs, and are provided with the retaining lugs25(the retaining lugs25a,25b) engageable with the through-hole12. Accordingly, when the plug20is inclined due to the external force in the direction opposite to the notch28a, in which direction the plug20is easily inclined, hook margins of the retaining lugs25a,25bare hardly reduced. That is, by providing the retaining lugs25at the positions where the hook margins of the retaining lugs25are not reduced at the time when the plug20is inclined due to an external force, it is possible to restrain the plug20from falling out. Therefore, in a case where the plug20includes the flange portion28having the notch28athat restricts the rotation around the axial center Cs, even if the plug20is inclined due to an external force, the plug20can hardly fall out of the through-hole12.

Further, in the present embodiment, the insertion portions24c,24dare formed at two positions opposed to each other across the axial center Cs on the straight line passing through the notch28aand the axial center Cs, which allows the plug20to be easily inserted straight into the through-hole12at the time when the plug20is inserted into the through-hole12. Further, since the insertion portions24c,24dformed at two positions opposed to each other across the axial center Cs are not provided with the retaining lugs25, the plug20is easily inserted into the through-hole12. That is, when the retaining lugs25are provided only at the positions where the hook margins of the retaining lugs25are not reduced at the time when the plug20is inclined due to an external force, it is possible to achieve both restraint of falling-off of the plug20and easiness of the insertion.

Further, in the present embodiment, the flange portion28is configured such that an arc where the notch28ais formed has a sector shape with an arc smaller than a semicircle, and therefore, and therefore, it is useful to provide the retaining lugs25at positions where the hook margins of the retaining lugs25are not reduced at the time when the plug20is inclined due to an external force in the direction opposite to the notch28ain which direction the plug20is easily inclined.

Further, in the present embodiment, the plug20is a breather plug provided with the hose joint portion26. Accordingly, in a case where the breather plug includes the flange portion28having the notch28athat restricts the rotation around the axial center Cs which might occur due to application of an external force to the breather hose, or the like reason, even if the breather plug is inclined due to the external force, the breather plug can hardly fall out of the through-hole12.

The embodiment of the present disclosure has been described in detail with reference to the attached drawings, but the present disclosure is applied to the other aspects.

For example, in the above embodiment, the plug20includes, as the insertion portions24, four insertion portions, i.e., the insertion portion24a, the insertion portion24b, the insertion portion24c, and the insertion portion24d. However, the present disclosure is not limited to this aspect. For example, the plug20may include, as the insertion portions24, at least the insertion portions24a,24bformed at two positions opposed to each other across the straight line passing through the notch28aand the axial center Cs and provided with the retaining lugs25a,25b. That is, in the plug20, the insertion portions24provided with the retaining lugs25may be formed at least at two positions opposed to each other across the straight line passing through the notch28aand the axial center Cs.

Further, in the above embodiment, the power transmission device accommodated in the housing10is, for example: a transmission for a vehicle, constituted by a planetary-gear automatic transmission, a synchromesh parallel two-shaft transmission, a DCT (Dual Clutch Transmission), a continuously variable transmission, or the like; a differential gear connected to the transmission for the vehicle; and the like.

Further, the above embodiment exemplifies, as the housing10, a transmission case in which a power transmission device is accommodated, and further exemplifies, as the plug20, a breather plug provided with the hose joint portion26, so as to describe the present disclosure. The present disclosure is not limited to the embodiment like the housing10and the plug20, but is applicable to the other embodiments. For example, the present disclosure can be also applied to a breather plug that does not include the hose joint portion26. Further, the present disclosure can be applied to a housing configured to accommodate members and the like constituting a vehicle, a housing divided into a main body and a cover and configured to accommodate some mechanisms and the like of an engine, and a plug for a vehicle to be inserted into a through-hole of such a housing, as a stopper that just buries the through-hole. Further, the present disclosure can be also applied to a plug for a vehicle to be inserted into a through-hole of a housing, merely as a hose joint.

These are merely one embodiment to the utmost, and the present disclosure can be performed in an embodiment to which various changes and improvements are added based on the knowledge of a person skilled in the art.