JP2013245752A - Breather structure of transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breather structure of a transfer capable of regulating a pressure in a device chamber while suppressing the outflow of oil content from the device chamber by an inexpensive structure in which the existing portion of a transfer case is diverted without using a breather valve.SOLUTION: A breather structure includes a narrow passage 32 formed of a gap between the outer surface of a bolt member 13 inserted into a bolt insertion hole 18a and the inner surface of the bolt insertion hole 18a, as a breather passage 30 allowing a device chamber 20 to communicate with the outside of a transfer case 5. The device chamber 20 communicates with the outside of the transfer case 5 through the narrow passage 32. By the structure, the narrow passage 32 is formed of a rather small space, so that the air contained in the internal air discharged from the device chamber and the outside air (gas content) are allowed to flow therethrough. However, the oil content (liquid content) contained in the internal air is difficult to flow therethrough. Consequently, the narrow passage 32 functions as a breather valve, and can regulate a pressure in the device chamber 20 while suppressing the outflow of the oil content from the device chamber 20 by an inexpensive structure.

Description

  The present invention relates to a breather structure for a transfer mounted on a vehicle such as an automobile.

  In a vehicle, for example, a 4WD automobile, a structure in which a transfer (power transmission device) is fastened to an output portion of a transmission directly connected to an engine is used. Many transfer units have a boss formed on the outer surface of the transfer case abutted against an installation portion already formed on the outer surface of the transmission case, for example, the tip of the boss, and a bolt inserted in the boss of the transfer case is inserted. A structure is used in which a bolt member is inserted from the hole and is screwed into a screw hole formed in a boss portion of the transmission case to be fastened to the transmission. Through this fastened transfer, the shaft output of the engine output from the transmission is distributed to the front and rear wheels.

In the transfer, it is required to adjust the internal pressure of the interior of the transfer case, specifically, the equipment room containing the power transmission component (because the internal air expands and contracts).
By the way, the equipment room is filled with an oil component, that is, an atmosphere of lubricating oil for lubricating power transmission parts (for example, by scraping the lubricating oil accumulated in the equipment room with gear parts or the like). For this reason, the internal air of the transfer case contains liquid components such as oil.

For this reason, in the transfer, a breather structure, specifically a breather valve such as a one-way valve, is used to discharge the internal air (exhaust gas) containing a liquid such as oil to the outside of the transfer case, and the internal pressure (internal pressure) of the equipment room. ) Is done.
In many cases, as disclosed in Patent Documents 1 and 2, a large-diameter hole for mounting a breather valve is formed on the outer surface of the transfer case, and the hole communicates with the equipment room (directly or indirectly). ) Is used. In other words, while suppressing the outflow of oil from the equipment room through the breather passage that connects the equipment room and the outside of the transformer case (atmosphere), specifically, the breather passage formed by the breather valve, the hole for attaching the valve, etc. The internal pressure (internal pressure) of the equipment room is kept almost atmospheric.

JP 10-138774 A JP 2010-14235 A

However, a breather structure that relies on such a breather valve uses an expensive breather valve, and therefore requires a considerable cost.
Accordingly, an object of the present invention is to provide a transfer breather structure capable of adjusting the pressure in the equipment room while suppressing the oil outflow from the equipment room with an inexpensive structure using the existing part of the transfer case without using a breather valve. It is to provide.

In order to achieve the above object, the breather passage for communicating the equipment room and the outside of the transfer case is a part of a portion for fastening the transfer case to the transmission case, that is, the outer surface of the bolt member and the bolt. The device room is communicated with the outside of the transfer case through a narrow passage formed by a gap between the inner surfaces of the insertion holes.
According to the same configuration, the narrow passage is quite narrow, so among the internal air containing the oil content (liquid content) of the equipment room, air that is a gas component and external air can be distributed, but the oil component that is a liquid component is distributed It is hard to do. Therefore, the narrow passage functions as a breather valve. As a result, the pressure in the equipment chamber can be adjusted while diverting part of the portion where the transfer case is fastened to the transmission case and suppressing the outflow of oil from the equipment room.

According to the second aspect of the present invention, the boss portion where the narrow passage is formed is provided at the uppermost portion of the transfer case so that the outflow of the oil (liquid component) contained in the internal air of the equipment room is effectively suppressed. Use the arranged boss.
In the invention according to claim 3, in order to suppress the outflow of the oil (liquid component) contained in the internal air more effectively, the liquid component contained in the exhaust from the equipment room is reduced in the middle of the route to the narrow passage. The separation chamber has a separation chamber for collecting and separating.

In the invention according to claim 4, the bottom surface of the separation chamber is inclined so that the narrow passage side is higher than the equipment chamber side so that the oil accumulated in the separation chamber does not easily flow out into the narrow passage and is easily returned to the equipment chamber. It was supposed to be
In the invention according to claim 5, the boss portion has an air release portion on the outer peripheral surface of the end portion so that the foreign matter is less likely to enter the narrow passage from the outside.

According to the first aspect of the present invention, since the narrow passage formed by the gap between the inner surface of the bolt insertion hole and the outer surface of the bolt member is quite narrow, the air or the external air that becomes the gas component of the internal air of the equipment room The oil component that is a liquid component becomes a passage that is difficult to distribute.
Therefore, the narrow passage functions as a breather valve, and the pressure of the equipment chamber can be adjusted while suppressing the outflow of oil from the equipment room without using an expensive breather valve.

Therefore, the breather structure can be an inexpensive structure that uses the existing part of the transfer case.
According to the invention of claim 2, the narrow passage is formed by using the uppermost boss portion of the transfer case, so that oil (liquid component) contained in the internal air of the equipment room does not easily enter the narrow passage. Furthermore, it is possible to effectively suppress the outflow of oil in the equipment room.

According to the invention of claim 3, by forming the separation chamber in the middle of the path leading to the narrow passage, exhaust from the equipment chamber, that is, oil (liquid component) contained in the internal air does not easily enter the narrow passage. Thus, the oil outflow can be suppressed more effectively.
According to the fourth aspect of the present invention, the oil accumulated in the separation chamber does not easily flow out into the narrow passage due to the inclination, and the outflow of oil can be further effectively suppressed. In addition, oil easily returns to the equipment room.

  According to the fifth aspect of the present invention, since the atmosphere opening portion opens to the atmosphere from a direction different from the narrow passage, it is difficult for foreign matter to enter the narrow passage from the outside of the transfer case.

The perspective view which shows the breather structure which concerns on one Embodiment of this invention with the transferer, transmission, and engine which incorporated the structure. The perspective view which shows that a transfer case is comprised from a two-part structure. The perspective view which shows the whole transfer with internal power transmission components. The perspective view shown with the breather channel | path similarly formed in a transfer case. The perspective view which shows the structure of the separation chamber formed in a transfer case. Sectional drawing of the relay path along the AA line in FIG. Sectional drawing of the separation chamber which follows the BB line in FIG. Sectional drawing of the narrow channel | path along CC line in FIG. FIG. 5 is a perspective view of the atmosphere opening portion when viewed from an arrow D in FIG. 4.

Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
FIG. 1 shows a power unit P of a vehicle, for example, a 4WD vehicle, FIG. 2 shows a transfer 3 constituting the power unit P, and FIG. 3 shows a power transmission component (illustrated by a broken line) of the transfer 3. . The power unit P is mounted on the front part of the vehicle. Incidentally, “F” in FIG. 1 indicates the front side of the vehicle, and “R” indicates the rear side of the vehicle.

  The power unit P includes an engine 1, a transmission 2 fastened to a crankshaft output portion (not shown) of the engine 1, and a transferer 3 fastened to the transmission 2. Although not shown, the transmission 2 houses a front-side differential gear mechanism that distributes shaft output to the left and right front wheels. The left and right shaft outputs distributed by the differential gear mechanism are transmitted from the distribution output portions (not shown) on both sides in the vehicle width direction of the transmission case 2a that forms the outline of the transmission 2 to the front wheel drive shaft (not shown). Is output and drives the front wheels.

  The transfer 3 is arranged in a direction adjacent to the engine 1 and fastened to one side surface (one side in the vehicle width direction) of the transmission case 2a. As shown in FIG. 3, the transfer 3 includes a transfer case 5 that is bolted to a side surface of the transmission case 2 a, and various power transmission components housed in the transfer case 5. .

Specifically, as shown in FIGS. 1 and 2, the transfer case 5 has a two-part structure having, for example, a cylindrical main body case 5a and a case cover 5b that closes the front end opening of the main body case 5a. It has been. Incidentally, the output shaft 6 has already been rotatably assembled on the rear side of the main body case 5a.
As shown in FIG. 2, the main body case 5a and the case cover 5b are joined together by forming a flange portion 7 on the entire circumference of the front end portion of the main body case 5a and on the entire circumference of the case cover 5b. The structure which joins both by forming the flange part 8 to join is used. Specifically, the main body case 5a and the case cover 5b are formed, for example, by forming boss portions 9 at a plurality of locations of the flange portion 8 of the case cover 5b, forming screw holes 10 on the mating surface 7a of the flange portion 7, and The bolt member 11 having a short overall length is screwed into the screw hole 10 through a bolt insertion hole (not shown) formed in the above.

  Further, for fastening (transfer installation) between the transfer case 5 and the transmission case 2a, a long bolt member 13 is used as shown in FIGS. 2 and 3, and the transfer case 5 is already attached to the outer surface of the transmission case 2a. A structure is used in which a part, that is, a plurality of installation parts projecting outward from around a distribution output part (not shown), for example, a boss part 14 for fastening a transfer is used.

  Specifically, a screw hole 14a is formed in the boss portion 14 for transfer coupling. For example, the flange portion 8 of the case cover 5 b is provided with a boss portion 16 having a dedicated bolt insertion hole 16 a at a point corresponding to the boss portion 14, in addition to the boss portion 9. A dedicated boss portion 18 (which constitutes the boss portion for fastening the transmission of the present application together with the boss portion 16) is also formed at a point on the outer peripheral surface of the main body case 5a corresponding to the boss portion 14. The boss portion 18 extends from one end (flange portion 7) of the main body case 5a to the other end (end of the main body case 5a), and penetrates the bolt from the mating surface 7a of the flange portion 7 to the opposite end surface. A hole 18a is formed. That is, as shown in FIGS. 2 and 3, the transfer 3 is configured such that after the body case 5 a and the case cover 5 b are fastened by the bolt member 11, the boss portion 18 of the transfer 3 is attached to the front end surface of the boss portion 14 of the transmission 2. After the transfer 3 is disposed around the distribution output portion of the transmission 2, the screw portion 13a of the bolt member 13 is screwed into the screw hole 14a of the boss portion 14 through the boss portions 16 and 18, As shown by a two-dot chain line in FIG. 4, the boss portion 14 and the boss portions 16 and 18 are fastened to the transmission 2.

  In the transfer case 5, as shown by broken lines (partially shown) in FIG. 3, an equipment chamber 20 is formed across each part of the main body case 5a and each part of the case cover 5b. In this equipment room 20, various power transmission components, for example, a cylindrical input shaft 22 extending between both sides of the transfer case 5, a relay shaft 24 arranged in parallel with the input shaft 22, and relaying from the input shaft 22 A gear mechanism 25 that transmits rotation to the shaft 24, a bevel gear mechanism 27 that transmits rotation from the relay shaft 24 to the output shaft 6 in a different direction, and the like are housed. The input shaft 22 is connected to a carrier body (not shown) of a differential gear mechanism built in the transmission 2, and rotation from the engine 1 is distributed to the input shaft 22 and transmitted to the output shaft 6 through the relay shaft 24. More specifically, the rotation of the output shaft 6 is transmitted to the rear wheels (neither shown) via the propeller shaft extending to the rear of the vehicle body, the rear differential gear device, and the drive shaft. Incidentally, although not shown, the drive shaft on the front side passes through the input shaft 22 toward the front wheel.

  The equipment chamber 20 of the transfer case 5 is configured to be filled with, for example, an oil component obtained by scraping the lubricating oil accumulated in the transfer case 5 with gear parts, that is, an atmosphere of the lubricating oil. That is, the internal air of the equipment room 20 includes a liquid component such as an oil component. For this reason, the part for which the lubricating oil is required, for example, the meshing portion of the gear is lubricated in the lubricating oil atmosphere.

  Here, when the gear 3 or the like rotates at a high rotation, the air in the transfer case 5 is warmed and expanded, and when the transfer 3 rotates at a low rotation, the air in the transfer case 5 contracts due to a decrease in temperature. Adjustment of the pressure is required. Therefore, the transfer case 5 is provided with a breather structure 29 for adjusting the internal pressure as shown by the broken line in FIG. For the breather structure 29, a structure is used in which a breather passage 30 is provided for communicating between the equipment room 20 and the outside of the transfer case 5. Normally, a breather valve is used. Here, a structure is used in which the internal pressure can be adjusted only by the breather passage 30 without using the breather valve, and the outflow of lubricating oil (liquid component) contained in the internal air is suppressed. ing. More specifically, the breather passage 30 adopts a structure in which an existing portion of the transfer 3, specifically, a portion for fastening the transfer case 5 to the transmission case 2 a is used. The structure of each part of the breather passage 30 is shown in FIGS.

  That is, attention is paid to the gap between the bolt insertion holes 18a through which the shaft portion 13b of the long bolt member 13 is inserted, that is, the gap between the outer surface of the bolt member 13 and the inner surface of the bolt insertion hole 18a. Then, the gap is considerably narrow and further extends in the axial direction (cylindrical shape), so that the air that is the gas contained in the internal air can be circulated, but the oil that is the liquid is difficult to circulate. Recognize.

  Therefore, as shown in FIGS. 4, 7, and 8, the breather passage 30 uses a narrow passage 32 formed by a gap between the outer surface of the bolt member 13 and the inner surface of the bolt insertion hole 18 a, and is narrowed using the relay passage 34. A structure for communicating with the passage 32 and the equipment room 20 is used. For example, a structure in which the air release portion 36 is provided on the outer peripheral surface of the end portion of the boss portion 18 is used as a portion to be opened to the atmosphere. In particular, in the narrow passage 32, a gap between the boss portions 16 and 18 disposed at the uppermost portion of the transfer case 5 is used so that oil (liquid component) from the equipment chamber 20 does not easily enter. Of course, in the case of the boss portions 16 and 18, the narrow passage 32 is secured by a long path from the end blocked by the bolt member 13 to the end where the boss portion end of the transmission case 2a is arranged. This is effective for suppressing the distribution of (liquid component) (FIG. 4).

  In particular, the relay path 34 is formed by a path that gains a distance so that a liquid component contained in the exhaust from the equipment room 20, that is, an oil component (liquid component) contained in the internal air does not easily enter. For example, the relay path 34 is formed by a route that extends in a direction away from the narrow passage 32 and communicates with the device room 20. Here, as shown in FIG. 4, the relay path 34 is, for example, the uppermost part of the flange parts 7, 8 extending in a direction away from the boss parts 16, 18, specifically, the uppermost part of both flange parts 7, 8. The first passage 38a formed between the surfaces and the second passage 38b formed in the side wall portion of the case cover 5b, for example, the rib portion 5c as shown in FIG. Narrow passageway with a route returning from the end of one passage 38a extending along the flange portions 7 and 8 to the central portion of the case cover 5b (the vicinity where the end portion of the relay shaft 24 is disposed) through the side wall portion of the case cover 5b. 32 is in communication with the end side of the equipment room 20.

  Among these, the 1st channel | path 38a is formed in the gas-liquid separation chamber 40 (equivalent to the separation chamber of this application). For example, as shown in FIGS. 4 and 7, the gas-liquid separation chamber 40 is formed of a triangular chamber space whose internal volume decreases as it goes from the second passage 38 b toward the narrow passage 32. Specifically, the triangular chamber space is, for example, a large triangle communicating with the mating surface 8a of the flange portion 8 of the case cover 5b as shown in FIG. 5 between the narrow passage 32 and the second passage 38b. A concave portion 39a having a shape is formed, and a concave portion 39b having a small triangular shape is formed on the mating surface 7a of the flange portion 7 of the main body case 5a. As a result, the gas component of the internal air of the equipment chamber 20, that is, the air is led out to the triangular chamber space through the second passage 38 b and is contained in the internal air (lubricating oil) while reaching the narrow passage 32. The liquid component is separated and collected at the bottom. In particular, as shown in FIG. 7, the bottom surface 40a of the triangular gas-liquid separation chamber 40 is higher on the side of the narrow passage 32 on the opposite side than the end side (equipment room side) where the end of the first passage 38b is arranged. The oil (liquid component) that is inclined and is stored in the gas-liquid separation chamber 40 is difficult to flow out into the narrow passage 32 (it is easy to return to the equipment chamber 20). In FIG. 7, θ represents the inclination angle of the bottom surface 40 a of the gas-liquid separation chamber 40.

  As shown in FIGS. 8 and 9, the atmosphere opening portion 36 has a structure that prevents foreign matter from entering the narrow passage 32 from the outside as much as possible. This is because an extremely shallow groove portion 41 is formed on the end surface of the boss portion 18 installed on the transmission 2 so as to penetrate from the inner surface to the outer surface of the boss portion 18, and an extremely thin opening is formed from a direction different from the narrow passage 32. Open to the atmosphere. In particular, since the boss portion 18 having the groove portion 41 is a boss portion disposed at the uppermost portion of the transfer case 5, the groove portion 41 is opened downward here to further prevent foreign matters from entering. That is, by opening the air release portion 36 to the gap between the transmission case 2a and the transfer case 5, the transmission case 2a itself or the transfer case 5 itself is used as an obstacle, and foreign matter enters the air release portion 36. It is difficult to follow.

  According to the breather structure 29 configured in this way, the internal air expanded in the equipment chamber 20 is introduced from the passage 38b, and the gas component contained in the internal air, that is, the air passes through the gas-liquid separation chamber 40, and the bolt insertion hole. 16a and 18a are led to the narrow passage 32. The air is led to the outside (atmosphere) from the groove portion 41 forming the atmosphere opening portion 36 through the narrow passage 32 having a long distance (FIGS. 6 to 8). At the stage of passing through the gas-liquid separation chamber 40, the liquid component contained in the exhaust from the equipment chamber 20, that is, the oil component (lubricating oil) contained in the internal air is separated and collected at the bottom (FIG. 7).

Here, the narrow passage 32 formed by a slight gap between the outer surface of the bolt member 13 and the inner surface of the boss portion 18 (bolt insertion hole 18a) has a characteristic that air can be sufficiently circulated and the oil component that is a liquid component is difficult to circulate. Therefore, the outflow of oil contained in the internal air (exhaust) to the outside can be suppressed.
Incidentally, when the equipment room 20 contracts as the temperature decreases, external air (atmosphere) is introduced into the equipment room 20 through the groove 41, the narrow passage 32, the gas-liquid separation chamber 40, and the passage 38b.

Such an air flow adjusts the internal pressure of the transfer chamber 3, that is, the internal pressure of the equipment chamber 20 containing the input shaft 22, the relay shaft 24, the gear mechanism 25, and the bevel gear mechanism 27 (all of which are power transmission components).
Thus, it can be seen that the narrow passage 32 formed by a slight gap between the outer surface of the bolt member 13 and the inner surface of the bolt insertion hole 18a can function as a breather valve.

Therefore, the breather passage 30 can adjust the pressure of the equipment chamber 20 while suppressing the outflow of oil from the equipment chamber 20 of the transfer 3 without using an expensive breather valve.
Therefore, the breather structure 29 of the transfer 3 can be an inexpensive breather passage 30 composed of a narrow passage 32 using the existing portion of the transfer case 5. In particular, the narrow passage 32 uses the uppermost boss portions 16, 18 far from the equipment room 20, so that oil from the equipment room 20 does not easily enter the narrow passage 32.

In addition, since the gas-liquid separation chamber 40 is formed in the middle, it becomes difficult for the oil component to enter the narrow passage 32, so that the outflow of the oil component (lubricating oil) can be reliably suppressed. In particular, since the bottom surface 40 a of the gas-liquid separation chamber 40 is inclined, the oil content is more difficult to flow out into the narrow passage 32. Further, the accumulated oil is easily returned to the equipment room 20.
In addition, since the atmosphere opening portion 36 of the boss portion 18 opens to the atmosphere from a direction different from that of the narrow passage, it is difficult for foreign matter to enter the narrow passage 32 from the outside of the transfer case 5. In addition, if it is formed by the extremely shallow groove portion 41, foreign matter is less likely to enter. In particular, when the groove 41 is downward, the transmission case 5a and the transfer case 5 are obstructions, and it is difficult for foreign matter to enter, and the performance of the breather structure 29 is further enhanced.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in one embodiment, the breather passage is formed using the boss portion located at a position close to the engine. However, the present invention is not limited thereto, and the breather passage may be formed using a boss portion located at a position away from the engine.

1 Engine 2 Transmission 2a Transmission case 3 Transfer 5 Transfer case 6, 22, 24, 25, 27 Output shaft, input shaft, relay shaft, gear mechanism, bevel gear mechanism (power transmission component)
11 Bolt member 16, 18 Boss part (Boss part for transmission fastening)
18a Bolt insertion hole 20 Equipment room 29 Breather structure 30 Breather passage 32 Narrow passage 34 Relay passage 40 Gas-liquid separation chamber (separation chamber)
40a Bottom 41 Groove (atmospheric open part)

Claims (5)

It has an equipment room for storing power transmission parts inside, a boss part for fastening the transmission that forms bolt insertion holes on the outside, and is fastened to the transmission case using bolt members that pass through the bolt insertion holes A transfer case comprising: a breather structure configured to provide a breather passage that communicates between the device room and the outside of the transfer case.
The breather passage is
A narrow passage formed by a gap between an outer surface of the bolt member inserted through the bolt insertion hole and an inner surface of the bolt insertion hole;
A breather structure for a transfer, wherein the device room and the outside of the transfer case are communicated with each other through the narrow passage.   2. The breather structure for a transfer according to claim 1, wherein the boss portion is disposed at an uppermost portion of the transfer case.   3. The breather structure for a transfer according to claim 1, further comprising a separation chamber that separates and collects a liquid component contained in the exhaust from the equipment chamber in the middle of the path leading to the narrow passage.   The transfer breather structure according to claim 3, wherein the bottom surface of the separation chamber is inclined so that the narrow passage side is higher than the equipment chamber side.   The transfer breather structure according to any one of claims 1 to 4, wherein the boss portion has an air release portion on an outer peripheral surface of the end portion.

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