JP2009127831A - Breather structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a breather structure which can reliably prevent oil leakage while sufficiently securing a breather passage. <P>SOLUTION: The breather structure 20 includes a case part 11, a cage 22, a breather unit 23, a first space part S1 and a second space part S2. The first space part S1 stored with oil 12 and outside air communicate via the roughly annular peripheral groove 22a or the like formed along the circumferential surface of the roughly cylindrical cage 22 formed on a part of the second space part S2 adjacent to the first space part S1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a breather structure for preventing an increase in pressure in a case part by communicating a space in a case part including a power transmission mechanism such as a transmission with outside air.

2. Description of the Related Art Conventionally, a transmission (transmission) mounted on a vehicle such as a construction machine is housed in a case in which oil for lubricating a gear, a bearing, or the like that connects an input shaft and an output shaft is stored.
For example, Patent Document 1 discloses a breather device in which an outer peripheral annular groove is provided on an outer peripheral portion of a retainer in order to prevent ejection of lubricating oil (oil) from a breather hole and to achieve compactness and simplification of the structure. Is disclosed.
Japanese Patent Laid-Open No. 5-209671 (published on August 20, 1993)

However, the conventional breather structure has the following problems.
That is, although the breather structure disclosed in the above publication employs a structure that performs gas-liquid separation of the atomized oil through the outer peripheral annular groove, the distance between the oil accumulation space and the breather structure is short. Therefore, there is a possibility that oil leakage cannot be prevented sufficiently.
The subject of this invention is providing the breather structure which can prevent an oil leak more reliably, ensuring a breather channel | path sufficiently.

The breather structure according to the first invention includes a case portion, a breather hole portion, a first space portion, a second space portion, a substantially cylindrical support member, and an outer peripheral groove. The case portion accommodates a power transmission mechanism having a plurality of shafts including an input / output shaft. The breather hole is provided in the upper part of the outer peripheral surface of the case part and communicates with the outside air. The first space portion is disposed inside the case portion and stores lubricating oil. The 2nd space part is the inside of a case part, and is arrange | positioned on the outer peripheral side rather than the 1st space part adjacent to the breather hole part. The substantially cylindrical support member supports a bearing that holds the shaft disposed in the second space portion, and covers an opening portion of the case portion formed in the axial direction of the shaft. The outer circumferential groove is formed along a substantially cylindrical outer circumferential surface of the support member, and serves as a breather passage that communicates the breather hole portion with the first space portion.
Here, in the case part containing the power transmission mechanism, the first space part for storing lubricating oil, the second space part adjacent to the breather hole part disposed on the outer peripheral surface, and the shaft axis A substantially cylindrical support member covering the opening portion of the case portion formed in the direction, and forming a peripheral groove along the outer peripheral surface of the substantially cylindrical support member, A breather passage is formed to communicate the outer circumferential groove with the first space.

Here, the breather hole portion is an opening hole formed in the vicinity of the outermost peripheral portion of the case portion so as to communicate with the second space portion. The support member is disposed so that a portion where the breather hole portion communicates with the second space portion is connected to a part of the outer circumferential groove, and the first space portion and the breather hole portion are communicated with each other. Block communication to the breather hole.
Thus, the outer peripheral groove formed along the outer peripheral surface of the support member covering the opening portion of the second space portion is extended from the first space portion where the lubricating oil is stored to the breather hole portion communicating with the outside air. Can be communicated with each other. That is, it is possible to ensure a sufficient distance from the oil storage portion to the breather hole portion communicating with the outside air, and to prevent the oil from directly moving to the breather hole portion via the outer peripheral groove portion. Moreover, even if oil scatters with rotation of the shaft in the second space portion, the second space portion and the breather hole portion are not in direct communication with each other, so that oil leakage from the second space portion is effective. Can be prevented. Therefore, it is possible to reliably avoid oil leakage to the outside of the case part due to the scattering of oil accompanying the rotation of the shaft or the pressure rise in the case part while sufficiently securing the breather passage to suppress the pressure rise in the case part. Can do.

The breather structure according to the second invention is the breather structure according to the first invention, and the outer peripheral groove is formed on the support member side.
Here, a groove (concave portion) formed on the outer peripheral surface side of the support member is used as the outer peripheral groove functioning as a breather passage for communicating the breather hole portion and the first space portion described above.
Thereby, the breather structure which can acquire the effect mentioned above can be comprised only by change of the shape of forming a crevice in the peripheral surface of a support member. In addition, since the thickness on the case portion side can be reduced compared to the configuration in which the concave portion is provided on the case portion side, the entire case can be reduced in size.

The breather structure according to the third invention is the breather structure according to the first or second invention, and the outer circumferential groove is formed on the inner circumferential surface side of the case portion facing the outer circumferential surface of the support member.
Here, a groove (concave portion) formed on the inner peripheral surface side of the case portion facing the outer peripheral surface of the support member as an outer peripheral groove functioning as a breather passage for communicating the breather hole portion and the first space portion described above. Used.
Thereby, the breather structure which can acquire the effect mentioned above can be comprised only by change of the shape of forming a crevice in the inner skin of a case part. Further, since the thickness on the support member side can be reduced compared to the configuration in which the concave portion is provided on the support member side, the entire apparatus can be reduced in size by reducing the thickness of the support member. Furthermore, when the recess formed in both the support member and the case portion is used as the outer peripheral groove, a breather passage having a sufficient cross-sectional area can be formed, so that oil leakage can be prevented more effectively. Can do.
The case part is preferably molded by casting or the like. In this case, it is possible to easily form a case portion including a highly accurate recess at low cost.

A breather structure according to a fourth aspect of the present invention is the breather structure according to any one of the first to third aspects of the present invention, wherein the breather structure is formed in a part of the case portion, and includes the first space portion and the outer peripheral groove. A communication passage for communicating is further provided.
Here, the first space portion in which lubricating oil is stored and the outer peripheral groove formed along the outer peripheral surface of the substantially cylindrical support member are connected to each other through a communication path formed in a part of the case portion. Communicate.
Thereby, it can be avoided that a large amount of oil scattered in the first space where the oil is stored flows into an outer peripheral groove as a breather passage formed along the outer peripheral surface of the support member. As a result, oil leakage from the breather hole through the breather passage can be effectively prevented.

The breather structure which concerns on 5th invention is the breather structure which concerns on 4th invention, Comprising: A communicating path is two holes which make a 1st space part and an outer periphery groove | channel communicate separately.
Here, as the communication path for communicating the first space in which the lubricating oil is stored and the outer circumferential groove formed along the outer circumferential surface of the substantially cylindrical support member, two are respectively communicated separately. Holes are used.
Thus, depending on the rotation direction of the shaft, one of the two holes formed as the communication path can be used as the inflow side and the other can be used as the outflow side. Therefore, the oil flowing into the breather passage in the case portion can be circulated so as to efficiently return to the first space portion, and oil leakage can be more effectively prevented.

  According to the breather structure according to the present invention, the breather passage is sufficiently secured to suppress the pressure rise in the case portion, while the oil splashes due to the rotation of the shaft and the pressure outside the case portion due to the pressure rise in the case portion. Oil leakage can be avoided reliably.

A transmission 10 employing a breather structure according to an embodiment of the present invention will be described below with reference to FIGS.
[Configuration of Transmission 10]
As shown in FIGS. 1 and 2, the transmission 10 according to the present embodiment is a multi-shaft transmission, and includes a case portion 11 that houses a power transmission mechanism, and a first portion formed in the case portion 11. The space portion S1 and the second space portion S2, the oil 12 stored in the first space portion S1, the shafts 13 and 14, the breather structure 20, and the bearings 24 and 25 (see FIG. 3) are provided. Yes.
The case portion 11 is a box-shaped member that houses the transmission 10, a torque converter (not shown), a clutch, and the like, and includes oil 12, shafts 13 and 14, gears 13 a, and bearings 24 and 25. In addition, a first space portion S1 that accommodates the shaft 13 and the bearing 24 and a second space portion S2 that accommodates the shaft 14 and the bearing 25 are formed inside the case portion 11. Further, the case portion 11 has an opening at an end portion in the axial direction of the shaft 13 on the first space portion S1 side. And this opening part is covered so that it may cover with the cage 21 mentioned later.

The first space S <b> 1 is formed near the center of the transmission 10 and stores lubricating oil 12 therein. In addition, the shaft 13, the bearing 24, and the like are accommodated in the first space S1. Further, the first space portion S1 is shielded from the outside air by a cage 21 that covers the opening of the case portion 11 formed at the axial end portion of the shaft 13.
The second space portion S2 is disposed on the outer peripheral side of the transmission 10 and adjacent to the first space portion S1 on the radially outer side of a circle centered on the shaft 13. Further, the shaft 14, the bearing 25, and the like are accommodated in the second space S2. A breather unit 23 including a breather hole that passes through part of the case 11 and communicates with the outside air is attached to the upper portion of the second space S2. Further, the second space portion S2 is sealed on the axial direction side by a cage 22 that covers the opening of the case portion 11 formed at the axial end portion of the shaft 14.

The oil 12 is stored in the first space portion S1 in order to lubricate gears, bearings, and the like housed in the case portion 11. Further, the oil 12 scatters in the case portion 11 as the shafts 13 and 14 and the gear 13a rotate, and moves to every corner in the case portion 11 to lubricate each component.
The end of the shaft 13 is supported by a bearing 24 disposed in the first space S1, and rotates integrally with the gear 13a.
The shaft 14 is supported at its end by a bearing 25 disposed in the second space S2, and is rotated by power input from an engine (not shown).
The breather structure 20 is a structure that forms a breather passage that communicates the first space S1 in which the oil 12 is stored with the breather unit 23 that communicates with the outside air, and separates the oil 12 and the gas from each other. Thereby, even when the temperature of the oil 12 and the like rises with the rotation of the shafts 13 and 14 and the like, the pressure rise in the case portion 11 can be effectively prevented while preventing the oil leakage from the breather unit 23. Can do. The detailed configuration of the breather structure 20 will be described in detail later.

The bearing 24 is a member that supports the end portion of the shaft 13 that serves as the rotation shaft of the gear 13a in the first space S1, and is held on the inner peripheral surface side of the substantially cylindrical cage 21 or the case portion 11. Yes.
The bearing 25 is a member that supports the end portion of the shaft 14 in the second space S <b> 2, and is held on the inner peripheral surface side of the substantially cylindrical cage 22.
[Breaser structure 20]
As shown in FIGS. 3 and 4, the breather structure 20 of the present embodiment includes the case portion 11 and the first and second space portions S <b> 1 and S <b> 2, the cage 21, the cage (support member) 22, and the breather. And a unit (breather hole) 23.
The case portion 11 includes two communication holes (communication passages) 11a, which are a part of the breather passage formed by the breather structure 20, in the portion between the first space portion S1 and the second space portion S2. 11b. The communication holes 11a and 11b function as a breather passage that connects the first space S1 and the second space S2 side. For example, as shown in FIG. 4, when the shaft 13 rotates in the direction of the arrow in the figure, the scattered oil 12 enters the outer peripheral groove 22a from one communication hole 11a. The oil 12 accumulated in the outer circumferential groove 22a is discharged from the other communication hole 11b and returns to the first space S1 again. When the rotation direction of the shaft 13 is reversed, the scattered oil 12 enters the outer peripheral groove 22a from the communication hole 11b and is then discharged from the communication hole 11a. In the breather structure 20 of the present embodiment, by repeating such a cycle, the oil 12 that has entered the outer circumferential groove 22a functioning as a breather passage is effectively circulated and guided again to the first space S1. be able to.

The cage 21 is a substantially cylindrical lid member that covers an opening formed at the axial end of the shaft 13 in the first space S1, and has a bearing 24 that supports the shaft 13 in a rotatable state. Supporting in terms of surface. The cage 21 is bolted to the outer wall surface of the case portion 11.
The cage (support member) 22 is a substantially cylindrical lid member that covers an opening formed at the axial end of the shaft 14 in the second space S2, and is a bearing that supports the shaft 14 in a rotatable state. 25 is supported on the inner peripheral surface side. Further, the cage 22 is bolted to the outer wall surface of the case portion 11 in the same manner as the cage 21. Furthermore, the cage 22 has a substantially annular outer peripheral groove (concave portion) 22a formed along a substantially cylindrical outer peripheral surface. The outer peripheral groove 22a communicates with the breather unit 23 in the vicinity of the upper end portion, and communicates with the two communication holes 11a and 11b formed in the case portion 11 in the vicinity of the lower end portion. Thereby, the first space S1 can be communicated with the outside air by the breather unit 23 through the two communication holes 11a and 11b and the substantially annular outer circumferential groove 22a.

The breather unit (breather hole portion) 23 is attached in the vicinity of the upper end surface of the case portion 11 and is configured to include a breather hole portion formed in a part of the case portion 11. The breather hole included in the breather unit 23 originally communicates with the second space S2, but is closed by the substantially cylindrical body portion when the cage 22 is mounted. As a result, the breather hole that communicates with the outside air is in a state of communicating only with the outer circumferential groove 22 a formed along the outer circumferential surface of the cage 22.
[Features of the breather structure 20]
(1)
As shown in FIG. 3 and the like, the breather structure 20 of the present embodiment includes a case portion 11, a cage 22, a breather unit 23, a first space portion S1, and a second space portion S2. Then, the first space S1 in which the oil 12 is stored and the outside air are moved along the outer peripheral surface of a substantially cylindrical cage 22 provided in a part of the second space S2 adjacent to the first space S1. It communicates via the formed substantially annular outer circumferential groove 22a and the like.

Thereby, even when the oil 12 stored in the first space portion S1 is scattered in the case portion 11 with the rotation of the shafts 13, 14 and the gears 13a, the portion where the oil 12 exists and the outside air A sufficient distance (height difference) from the communicating breather unit 23 can be ensured, and oil leakage from the breather hole can be effectively prevented. Further, since the outer circumferential groove 22a connecting the first space S1 and the breather hole is substantially annular, it is possible to avoid the scattered oil 12 from directly flowing into the breather hole. As a result, the outer peripheral groove 22a formed along the outer peripheral surface of the cage 22 functions sufficiently as a breather passage, and the oil 12 that has moved through the breather passage leaks out of the breather hole. Can be effectively prevented.
(2)
In the breather structure 20 of the present embodiment, as shown in FIG. 3 and the like, an outer peripheral groove 22a that functions as a breather passage that communicates the breather hole of the breather unit 23 with the first space S1 in which a large amount of oil 12 is present. It is formed on the outer peripheral surface side of the substantially cylindrical cage 22.

Thereby, it is possible to obtain the breather structure 20 that achieves the above-described effect by only changing the shape by forming a recess (groove) in a part of the cage 22 that is fitted into a part of the case part 11 and fixed by a bolt. it can.
(3)
In the breather structure 20 of the present embodiment, as shown in FIGS. 3 and 4, a part of the case portion 11 that partitions the first space portion S1 and the second space portion S2 is formed on the outer peripheral surface of the cage 22. Communication holes 11a and 11b for communicating with the outer peripheral groove 22a are provided.
Thereby, it is possible to prevent the oil 12 in the first space portion S1 scattered in the case portion 11 as the shaft 13 rotates from flowing into the outer peripheral groove 22a at a stretch. As a result, the oil 12 is prevented from leaking from the breather hole by avoiding excessive inflow of the oil 12 into the outer circumferential groove 22a serving as the breather passage while appropriately scattering in the case portion 11 to lubricate each component. be able to.

(4)
In the breather structure 20 of the present embodiment, as shown in FIGS. 3 and 4, a communication path formed in a part of the case portion 11 that communicates the first space S <b> 1 and the outer peripheral groove 22 a formed in the cage 22. As an example, two communication holes 11a and 11b are employed.
Thereby, even when the oil 12 scattered in the first space S1 due to the rotation of the shaft 13 or the like enters the outer peripheral groove 22a, for example, the oil 12 that has flowed in from the one communication hole 11a passes through the other communication hole 11b. Can be discharged. As described above, the oil 12 that has entered the outer circumferential groove 22a is effectively circulated so that the oil 12 does not accumulate in the outer circumferential groove 22a. As a result, it is possible to more reliably prevent oil leakage from the breather hole while ensuring sufficient ventilation as the breather passage.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.
(A)
In the embodiment described above, an example in which the outer peripheral groove 22 a formed along the outer peripheral surface of the cage 22 as the breather passage is formed on the outer peripheral surface side of the cage 22 has been described. However, the present invention is not limited to this.
For example, as shown in FIG. 5, a breather structure 120 in which an outer peripheral groove 111 c as a breather passage is provided on the inner peripheral surface side of the case portion 111 that is inserted into the cage 22 and faces the outer peripheral surface thereof may be used.

Also in this case, the breather unit 23 (breather hole portion) and the first space portion S1 are communicated with each other via the substantially annular outer circumferential groove 111c and the two communication holes (communication passages) 111a and 111b. A sufficient distance from the first space S1 in which the oil 12 is stored to the breather hole (breather unit 23) communicating with the outside air can be secured. Therefore, it is possible to obtain the same effect as described above that the pressure increase in the case portion 111 during the rotation of the shafts 13 and 14 can be avoided and the oil leakage can be effectively prevented.
(B)
In the above-described embodiment, an example in which the outer circumferential groove 22a that communicates the first space portion S1 and the breather unit 23 and the first space portion S1 are communicated via the two communication holes 11a and 11b has been described. However, the present invention is not limited to this.

For example, as shown in FIG. 6, the cage 22 can be connected to the cage 22 through one communication hole (communication path) 211 a formed in a part of the case portion 211 that partitions the first space portion S1 and the second space portion S2. A breather structure 220 may be used in which the outer circumferential groove 22a communicates with the first space S1.
Even in this case, oil flows into the outer peripheral groove 22a from the first space S1 through the communication hole 211a to prevent oil leakage, and when the inside of the case becomes hot, the air is released to the outside. be able to.
However, the oil 12 that has flowed into the outer circumferential groove 22a is efficiently circulated and returned to the first space S1 again, so that oil leakage can be effectively avoided as in the above embodiment. It is more preferable to provide two or more communication holes 11a and 11b.

(C)
In the above-described embodiment, the breather structure 20 including the two communication holes 11a and 11b that communicate the outer circumferential groove 22a formed along the outer circumferential surface of the cage 22 and the first space S1 has been described as an example. . However, the present invention is not limited to this.
For example, the first space portion and the outer peripheral groove may be communicated via three or more communication paths.
In this case, it is possible to efficiently circulate the oil that has flowed into the outer peripheral groove and prevent oil leakage more effectively.
(D)
In the above embodiment, the outer circumferential groove 22a that communicates the first space S1 and the breather unit 23 and the first space S1 are connected via one or two communication holes 11a, 11b, 111a, 111b, and 211a. An example of communicating was explained. However, the present invention is not limited to this.

For example, as shown in FIGS. 7 and 8, a breather adopting a configuration in which the outer circumferential groove of the cage (support member) 322 and the first space portion S1 are communicated by casting without providing a communication passage in the case portion 311. Structure 320 may be used.
In this case, an effect similar to that of the above-described breather structure can be obtained by functioning so that the outer peripheral groove of the cage also serves as a communication path.

  The breather structure of the present invention secures the breather passage sufficiently and suppresses the pressure rise in the case portion, while preventing oil leakage to the outside of the case portion due to the scattering of oil accompanying the rotation of the shaft and the pressure rise in the case portion. Since the effect of being able to avoid reliably is produced, the present invention can be widely applied to the breather structure provided in the case portion that accommodates various rotating bodies.

1 is an overall view showing a configuration of a transmission that employs a breather structure according to an embodiment of the present invention. The front view of the transmission of FIG. The enlarged view which shows the structure of the breather structure contained in the X part of FIG. The enlarged front view which shows the movement state of the oil in the breather structure of FIG. The enlarged view which shows the structure of the breather structure which concerns on other embodiment of this invention. The enlarged front view which shows the structure of the breather structure which concerns on other embodiment of this invention. The front view which shows the structure of the transmission containing the breather structure concerning other embodiment of this invention. The enlarged view which shows the structure of the breather structure contained in the transmission of FIG.

Explanation of symbols

10 Transmission 11 Case part 11a, 11b Communication hole (communication path)
12 Oil 13 Shaft 13a Gear 14 Shaft 20 Breather structure 21 Cage 22 Cage (support member)
22a peripheral groove 23 breather unit (breather hole)
24 Bearing 25 Bearing 111 Case part 111a, 111b Communication hole (communication path)
111c outer peripheral groove 120 breather structure 211 case part 211a communication hole (communication path)
220 Breather structure 311 Case part 320 Breather structure 322 Cage (support member)
S1 1st space part S2 2nd space part

Claims (5)

A case portion that houses a power transmission mechanism having a plurality of shafts including an input / output shaft;
A breather hole that is provided on the outer peripheral surface of the case part and communicates with the outside air;
A first space that is disposed inside the case portion and stores lubricating oil;
A second space portion disposed inside the case portion, adjacent to the breather hole portion and disposed on an outer peripheral side of the first space portion;
A substantially cylindrical support member that supports a bearing that holds the shaft disposed in the second space, and covers an opening portion of the case portion formed in the axial direction of the shaft;
An outer circumferential groove that is formed along a substantially cylindrical outer circumferential surface of the support member, and that serves as a breather passage that communicates the breather hole with the first space;
Breather structure with. The outer circumferential groove is formed on the support member side,
The breather structure according to claim 1. The outer peripheral groove is formed on the inner peripheral surface side of the case portion facing the outer peripheral surface of the support member.
The breather structure according to claim 1 or 2. It is formed in a part of the case part, and further includes a communication path that communicates the first space part and the outer peripheral groove,
The breather structure according to any one of claims 1 to 3. The communication path is two holes for separately communicating the first space portion and the outer peripheral groove,
The breather structure according to claim 4.

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