JP2021050801A - Breather - Google Patents

Abstract

To inhibit water from penetrating into a case.SOLUTION: A breather 12 includes: a breather body 16 attached to an airtight case 14, the breather body having a ventilation passage 18, allowing communication between the interior and the exterior of the case, at an axis part; a flange part 17 provided at a longitudinal intermediate part of the breather body and protruding to the outer side in a radial direction; a cap 22 which covers a portion of the breather body located at the opposite side of the case with respect to the flange part and forms a gap 25 with the flange part; and a cover 30 which is attached to the cap and covers the cap, the gap, and the flange part from the outer side in the radial direction.SELECTED DRAWING: Figure 1

Description

This disclosure relates to breathers.

The breather is attached to an airtight case such as a transmission, and suppresses the pressure rise inside the case by appropriately releasing the pressure raised due to the temperature rise inside the case to the outside of the case. By suppressing the pressure rise in the case, it is possible to prevent the lubricating oil flowing in the case from being pushed by the excessive pressure in the case and flowing out from the seal portion or the like. Generally, the breather is normally closed to seal the inside of the case, but when excess gas is generated inside the case, it is opened and the pressure inside the case is released to the outside of the case. Suppress the rise.

The breather has a breather body having a ventilation path communicating inside and outside of the case at the axial center, a flange portion provided in the middle portion in the longitudinal direction of the breather body and protruding outward in the radial direction, and a flange portion on the opposite side of the case to the flange portion. It is provided with a cap that covers the part of the breather body that is located.

JP-A-2007-107694

By the way, water may adhere to the gap between the flange portion and the cap in a rainy environment or the like. Then, when the inside of the case becomes negative pressure, the water may be sucked and infiltrate into the case through the ventilation path.

Therefore, this disclosure was devised in view of such circumstances, and its purpose is to provide a breather capable of suppressing the ingress of water into the case.

According to one aspect of the present disclosure
A breather body that is attached to an airtight case and has a ventilation path that communicates with the inside and outside of the case at the axis.
A flange portion provided in the middle portion in the longitudinal direction of the breather body and protruding outward in the radial direction, and a flange portion.
A cap that covers a portion of the breather body located on the opposite side of the case with respect to the flange portion and that forms a gap between the flange portion and the cap.
A cover attached to the cap and covering the cap, the gap, and the flange portion from the outside in the radial direction.
A breather is provided, which is characterized by being equipped with.

Preferably, the breather further comprises a tool engaging portion provided on a portion of the breather body located on the case side with respect to the flange portion and projecting outward in the radial direction.
The cover covers the tool engaging portion from the outside in the radial direction.

According to the present disclosure, it is possible to suppress the infiltration of water into the case.

It is sectional drawing which shows the breather which concerns on this embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

FIG. 1 is a cross-sectional view showing a breather according to the present embodiment. The breather 12 of the present embodiment is attached to the case 14 of the transmission of the vehicle. A plurality of gears and lubricating oil for lubricating them are housed in the case 14. The case 14 is airtightly or oiltightly sealed by an oil seal or the like (not shown) to prevent leakage of lubricating oil.

When the gears rotate in the case 14, the temperature inside the case 14 rises due to frictional heat, and the pressure inside the case 14 rises. When this pressure rises above a predetermined valve opening pressure, the breather 12 is opened and the pressure is released to the outside of the case 14, and the pressure rise inside the case 14 is suppressed.

The breather 12 is fastened and fixed to a female screw hole 13 penetrating the case 14 at one end, that is, the base end, in the direction of the central axis C, that is, in the axial direction. Further, the breather 12 separates from the case 14 toward the other end side in the axial direction, that is, the tip end side. Therefore, the axial base end side is the case 14 side, and the axial tip side is the opposite side of the case 14.

The breather 12 includes a breather main body 16 attached to the case 14, a flange portion 17 provided in the middle portion in the longitudinal direction of the breather main body 16 and projecting outward in the radial direction, and a breather main body located on the tip side in the axial direction with respect to the flange portion 17. It is provided with a cap 22 that covers the portion 16. The breather main body 16 has a ventilation passage 18 communicating with the inside and outside of the case 14 at the axial center portion.

The breather body 16 has a substantially circular tubular shape coaxial with the central axis C. A male screw portion 29 that is fastened and fixed to the female screw hole 13 is provided at the axial base end portion of the breather main body 16. The male screw portion 29 and the female screw hole 13 are formed by a pipe taper screw.

The flange portion 17 has an annular plate shape coaxial with the central axis C. The cap 22 has a bottomed cylindrical shape coaxial with the central axis C, and is attached to the breather main body 16 with its open end 23 facing the axial base end side. The cap 22 is made of resin.

The cap 22 is attached to the breather body 16 by snap fitting. That is, a diameter-expanded portion 15 having a pointed diameter is integrally provided at the axial tip portion of the breather main body 16. Further, a protrusion 21 projecting inward in the radial direction is integrally provided on the inner peripheral surface of the cap 22. When the cap 22 is placed on the breather body 16 from the tip side in the axial direction and moved to the base end side in the axial direction, after the protrusion 21 hits the diameter-expanded portion 15, the cap 22 is elastically expanded and deformed, and the protrusion 21 is deformed. Ride on the enlarged diameter portion 15. When the protrusion 21 completely gets over the diameter-expanded portion 15, the cap 22 returns to its original shape, and the protrusion 21 is located on the axially proximal end side of the diameter-expanded portion 15. As a result, the protrusion 21 engages with the enlarged diameter portion 15 and prevents the cap 22 from coming off.

Further, the breather 12 includes a valve body 20 that opens and closes the ventilation passage 18, and a spring 24 that urges the valve body 20 in the closing direction. The valve body 20 and the spring 24 are fitted in the axial gap between the cap 22 and the breather main body 16 in the cap 22.

The valve body 20 has a disk shape coaxial with the central axis C. The valve body 20 is seated on the tip surface of the enlarged diameter portion 15 of the breather body 16 and opens and closes the tip opening of the ventilation path 18 that opens at the tip surface. The spring 24 is formed by a coil spring arranged coaxially with the central axis C. The spring 24 is arranged in a compressed state between the cap 22 and the valve body 20, and urges the valve body 20 so that the valve body 20 closes the tip opening of the air passage 18.

The base end side end face of the open end 23 of the cap 22 forms a minute axial gap 25 with the tip end side end face of the flange portion 17. However, in the case of the present embodiment, the packing 19 is attached to the end surface on the tip end side of the flange portion 17, and the gap 25 is reduced to a smaller gap 27. In the case of this embodiment, the size of the gaps 25 and 27 is about several millimeters (exaggerated in the figure).

In addition, although not shown, a minute gap is also formed in the contact portion between the protrusion 21 and the enlarged diameter portion 15 and the contact portion between the valve body 20 and the breather main body 16. The sizes of these gaps and the gaps 25 and 27 are such that gas can pass through but dust cannot pass through.

Through these gaps, the inside and outside of the case 14 are always communicated. Therefore, when the internal pressure of the case 14 is less than the predetermined valve opening pressure, the breather 12 is in the closed valve state, but gas moves back and forth inside and outside the case 14 (that is, breathes) through these gaps and according to the pressure difference between the inside and outside of the case 14. ).

On the other hand, when the internal pressure of the case 14 rises above the valve opening pressure, the valve body 20 moves toward the tip end side in the axial direction against the force of the spring 24 to open the tip opening of the ventilation path 18. As a result, the breather 12 is opened, the pressure inside the case 14 is released, and the pressure rise inside the case 14 is suppressed.

In order to attach the breather body 16 to the case 14, a tool engaging portion 28 for engaging a tool such as a spanner is provided on the breather body 16. The tool engaging portion 28 is provided at a portion of the breather main body 16 located on the axially proximal end side with respect to the flange portion 17, and is provided at a position relatively close to the male screw portion 29. The tool engaging portion 28 protrudes outward in the radial direction from the breather main body 16. The cross-sectional shape of the tool engaging portion 28 perpendicular to the axial direction is hexagonal. However, other shapes may be used.

In the breather 12 of the present embodiment, when water due to rainwater or the like adheres to the gap 25 (specifically, the gap 27) between the cap 22 and the flange portion 17, when the inside of the case 14 becomes negative pressure, the pressure is increased. There is a risk that water will be sucked into the case 14. That is, the water in the gap 27 may be sucked through the gap between the protrusion 21 and the enlarged diameter portion 15 and the gap between the valve body 20 and the breather main body 16, and further sucked into the case 14 through the ventilation passage 18.

If water infiltrates into the case 14, the lubricating oil in the case 14 may be mixed with water and deteriorate the lubricating oil.

Therefore, in the present embodiment, the cover 30 is provided in order to suppress the adhesion of water to the gap 27. The cover 30 is attached to the cap 22 and covers the cap 22, the gap 27, and the flange portion 17 from the outside in the radial direction. In particular, the cover 30 of the present embodiment also covers the tool engaging portion 28 from the outside in the radial direction.

The cover 30 is integrally formed of an elastic material such as rubber or a material similar thereto. The cover 30 has a bottomed cylindrical shape coaxial with the central axis C, is press-fitted to the outside of the cap 22 with its open end 32 facing the axial base end side, and is detachably attached. The inner diameter of the cover 30 on the base end side of the fitting portion is increased, and the cover 30 is separated from the cap 22, the flange portion 17, and the tool engaging portion 28 in a non-contact state in the radial direction.

The axial position of the end surface 34 of the open end 32 is at least on the proximal end side of the gap 27, preferably on the proximal end side of the flange portion 17, and more preferably on the proximal end side of the tool engaging portion 28 as in the present embodiment. is there. Further, in order to prevent the cover 30 from interfering with the case 14, it is preferable that the end surface 34 is located closer to the tip side than the case 14. However, in order to prevent water from entering the cover 30, it is preferable that the end face 34 is close to the case 14.

Since the cover 30 is provided in the present embodiment, it is possible to prevent external water from adhering to the gap 27 between the cap 22 and the flange portion 17. Therefore, even if the pressure inside the case 14 becomes negative, it is possible to prevent water from being sucked into the case 14 and infiltrating. Furthermore, deterioration of the lubricating oil in the case 14 can be suppressed.

Further, since the tool engaging portion 28 is covered with the cover 30, even if water enters the cover 30, the tool engaging portion 28 blocks the water and the water adheres to the gap 27 as shown by the arrow W. That can be further suppressed. Therefore, the infiltration of water into the case 14 can be further suppressed.

Although the embodiments of the present disclosure have been described in detail above, various other embodiments and modifications of the present disclosure can be considered.

(1) For example, the packing 19 may be omitted.

(2) The case does not have to be the case of the transmission, and may be, for example, the case of the final reduction gear, the crankcase of the internal combustion engine, or the like.

The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the ideas of the present disclosure defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be construed in a limited manner and may be applied to any other technique belonging within the scope of the ideas of the present disclosure.

12 Breather 14 Case 16 Breather body 17 Flange 18 Vent 22 Cap 25 Gap 28 Tool engagement 30 Cover

Claims (2)

A breather body that is attached to an airtight case and has a ventilation path that communicates with the inside and outside of the case at the axis.
A flange portion provided in the middle portion in the longitudinal direction of the breather body and protruding outward in the radial direction, and a flange portion.
A cap that covers a portion of the breather body located on the opposite side of the case with respect to the flange portion and that forms a gap between the flange portion and the cap.
A cover attached to the cap and covering the cap, the gap, and the flange portion from the outside in the radial direction.
Breather characterized by being equipped with. A tool engaging portion provided on the portion of the breather main body located on the case side with respect to the flange portion and projecting outward in the radial direction is further provided.
The breather according to claim 1, wherein the cover covers the tool engaging portion from the outside in the radial direction.

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