JP2003161362A - Breather apparatus for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an oil blow in a breather apparatus even when a liquid level has risen due to foam produced by agitation. <P>SOLUTION: In the breather apparatus for communicating a space inside a case of an automatic transmission with the atmosphere, a hollow portion 30 of a power transmitting shaft 3 serves as a breather chamber, and a breathing passage 51 is provided so as to open at the hollow portion 30. By this configuration, oil and its bubbles are moved toward the outside of the hollow portion by vapor-liquid separating action due to a centrifugal force caused by the rotation of the power transmitting shaft. Consequently, the suction of oil into the breathing passage opened at the breather chamber is prevented regardless of the rise of the liquid level in the case, and the oil blow following the breathing is eliminated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather device for preventing pressure from being confined in an inner space of a case in an automatic transmission, and more particularly to a technique for preventing oil blowout during breathing of the breather device.

[0002]

2. Description of the Related Art An automatic transmission is constructed in such a manner that the pressure inside a case for accommodating its speed change mechanism and valve body rises or falls to a certain degree or more with respect to the outside air pressure due to heat generated by the operation of the mechanism and changes in the outside air temperature. In addition, a breather device is provided in order to eliminate the difference between the internal and external pressures of the case by breathing. In addition, in the automatic transmission case, for lubrication and cooling of each part of the transmission mechanism,
Circulation of ATF (automatic transmission hydraulic fluid: oil in this specification) is performed. Therefore, the oil for this circulation is held in the case at a constant liquid level.

By the way, since oil has a low viscosity at high temperatures, it may be agitated by high-speed rotation of the rotary member of the speed change mechanism to foam and the liquid level may rise abnormally. In order to achieve both breathing of the air in the case and prevention of discharge of oil in the form of bubbles mixed in the air, conventionally, the transmission case side opening of the breather device is located at a high position of the case, for example, in a horizontal transaxle. In the automatic transmission that takes the form, it is provided on the upper side cover that closes the side portion of the case.

[0004]

However, even with the breather arrangement as described above, with the increase in rotation speed of the transmission mechanism, for example, the differential device in an automatic transmission in the form of the transaxle rotates at high speed and agitates. When the amount of foaming increases due to violent pressure, the liquid level rises extremely due to mixing of bubbles, and in extreme cases, the inside of the case is completely filled with bubbles, and oil is ejected from the breather device. Sometimes. The problem of oil blowing in such a case is a problem that is difficult to solve with the existing concept of simply preventing the intake of oil by the relationship between the position of the transmission case side opening of the breather device and the oil level.

Therefore, according to the present invention, by positively excluding the inflow of foamy oil into the transmission case side opening of the breather device, the oil blowing is prevented without being affected by the rise in the liquid level. A main object of the invention is to provide a breather device for an automatic transmission that can perform the operation.

[0006]

[Means for Solving the Problems] The above-mentioned object is to claim 1.
As described in, in the breather device for communicating the case internal space of the automatic transmission with the outside air, a hollow portion communicating with the case internal space of the rotating member of the transmission mechanism is provided as a breather chamber, and a ventilation path that opens into the breather chamber is provided. This is achieved by the configuration characterized in that

In the above structure, as described in claim 2, it is effective that the ventilation passage is open to the breather chamber at the axial center of the rotary member.

More specifically, in the above structure, as described in claim 3, the ventilation passage is composed of a breather pipe which is separate from the case, and one end of the breather pipe is a hollow member of the rotating member. It is possible to adopt a configuration in which it is inserted into the portion and opened in the breather chamber.

In any one of the above configurations, the rotating member may be a counter shaft of a speed change mechanism.

In any one of the above structures, as described in claim 5, the hollow portion constitutes a part of a lubricating oil passage for circulating oil for lubricating the speed change mechanism in the case, and the hollow portion is connected to the hollow portion. It is effective that the inflow of oil is set by narrowing the oil passage on the supply side that reaches the hollow portion.

In any one of the above configurations, as described in claim 6, the hollow portion may be configured to communicate with the discharge side oil passage.

[0012]

According to the constitution of the above-mentioned claim 1,
The breather chamber is a hollow part that communicates with the space inside the case of the rotating member of the speed change mechanism, so that the area where bubbles do not enter is small, and the breather chamber is a space that constantly rotates during operation of the automatic transmission. Even if there are bubbles or bubbles thereof, the oil or bubbles thereof are removed from the outer peripheral side of the hollow portion by the centrifugal force that acts on them, so that it is possible to prevent the oil from being sucked into the ventilation passage opened in the breather chamber. Therefore,
According to this breather device, the gas-liquid separating action by the rotation of the rotating member can prevent the oil blowing due to the breathing even when there is a lot of foaming due to the stirring of the oil in the case.

Further, according to the second aspect of the invention, since the opening is located at the axial center of the rotating member where the gas-liquid separating action is most remarkable, the oil blow associated with breathing can be prevented more reliably. can do.

Next, in the structure according to the third aspect, the ventilation passage forming the breather device can be formed by the breather pipe including the opening inside the case. Therefore, according to this configuration, it can be applied to a conventional transmission case without significantly changing the structure of the case.

Further, in the structure according to claim 4, since the breather chamber is defined in the counter shaft, the breather chamber can be placed at a higher position on the case than the main shaft and the differential shaft of the transmission mechanism. Therefore, according to this configuration,
Due to the synergistic effect of the gas-liquid separation action and the high level of the opening in the case of the ventilation passage, it is possible to more reliably prevent the oil blowing accompanying breathing.

Further, in the structure according to the fifth aspect, even in a transmission in which the hollow portion of the rotating member serves as an oil circulation path, the inflow of oil into the hollow portion of the rotating member is restricted,
The amount of oil in the breather chamber can be limited, so that the above-mentioned respective effects mainly including the gas-liquid separating action by the rotation of the rotating member can be obtained without any trouble.

Further, in the structure according to the sixth aspect, by restricting the inflow of the oil into the hollow portion of the rotating member and discharging the oil from the hollow portion at all times, the breather chamber defined in the hollow portion is formed. The amount of oil can be regulated. Therefore, the breather chamber is not filled with oil, and the gas-liquid separating action by the rotation of the rotating member is always stable.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows F as an application target of the present invention.
Fig. 3 shows an axially deployed cross section of an automatic transmission in the form of a transversal transaxle for an F (front engine / front drive) vehicle. In this type of automatic transmission, a torque converter T and a main body of a transmission mechanism including a planetary gear set G, each clutch C and a brake B are arranged on a main shaft X coaxial with an engine shaft, and an output from the main shaft X side. Power is transmitted to the differential device D on the side of the differential shaft Z, which is parallel to the main axis X, via the counter shaft on the counter axis Y, which is also parallel to the main axis X. Therefore, the counter shaft, which is between the main shaft X and the differential shaft Z and constitutes the rotating member on the power transmission flow, is
When the vehicle is running, it always rotates because it is a power transmission shaft.
The breather device in this form utilizes the characteristic of constant rotation of the counter shaft as such a rotating member,
It achieves the intended purpose.

As shown in FIG. 3 by enlarging the axial section of the counter shaft Y, the counter shaft 3 is fixed to the end wall of the transmission case 10 and the engine side opening of the transmission case 10. Both ends of the end wall 11 are rotatably supported by roller bearings 31 and 32. Further, a thrust bearing 35 is interposed between the shaft end of the counter shaft 3 and the end wall of the converter housing 11. The counter shaft 3 is integrally formed with a diff drive pinion gear 33 that meshes with a diff ring gear 42 fixed to a diff case 41 of a differential device D (see FIG. 1). A counter driven gear 34 that meshes with the counter drive gear 21 on the spindle X side is arranged. Also, counter driven gear 3
4 and the outer race of the roller bearing 32,
The thrust bearing 36 is interposed.

A cylindrical hollow portion 30 is formed in the counter shaft 3 by a hole penetrating its axis. On the transmission case end wall side of the hollow portion 30, referring also to FIG. 4 showing the support portion of the counter shaft 3 to the case 10, the gap between the shaft end and the case side shaft end housing portion is By communicating with the internal space of the case through the oil passage on the supply side and the oil passage on the discharge side in the constricted state, the internal space of the case is ventilated. That is, the case groove 10a for ventilation which passes along the outer race outer peripheral side of the roller bearing 32 is formed on the upper side of the support portion, and the ventilation case provided on the outer race outer peripheral side of the roller bearing 32 is formed on the lower side of the support portion. A case groove 10b for discharging oil is formed. Through the space between the case grooves 10a and 10b and the bearing rollers and the gap between the counter driven gear 34 and the case wall, the hollow portion 30 is in parallel communication with the inner space of the case in an oil passage narrowed state. In addition, the converter housing end wall side of the hollow portion 30 has an oil passage 1 formed in the housing wall.
1a, through the oil passage of the oil pump cover, it communicates with the oil supply passage of the lubricating pressure leading to the valve body (not shown). A plug 37 having a predetermined orifice opening diameter is fitted into the opening of the oil passage 11a.

The breather device according to the present invention comprises a hollow portion 30 which communicates with the space inside the case 10 of the counter shaft 3 as a breather chamber, and is provided with a ventilation passage which opens into the breather chamber. In this embodiment, the ventilation path is configured by the breather pipe 51 that is separate from the case 10, and one end of the breather pipe 51 has the counter shaft 3
The hollow portion 30 is aligned with the axis and is inserted coaxially, and opens in the breather chamber at the axial center portion of the counter shaft 3. The breather pipe 51 is configured to have a horizontal portion that is inserted into the hollow portion 30 and an upright portion that rises vertically through a bending portion that follows the horizontal portion. The horizontal portion is a portion that passes through a stepped hole in the end wall of the case 10. A bulging portion having an outer diameter corresponding to the inner diameter on the large diameter side of the hole is formed, and the horizontal portion at the tip of the bulging portion is reduced to an outer diameter corresponding to the inner diameter on the small diameter side of the hole. ing. Breather pipe 51 having such a configuration
Fits the seal ring to the horizontal part and inserts it into the stepped hole to press the seal ring between the stepped part of the stepped hole and the bulging part to seal the part passing through the stepped hole. I am trying. The breather pipe 51 is prevented from coming off by bolting a stopper fixed to the breather pipe 51 to the case wall.

Since the hollow portion 30 of the counter shaft 3 constitutes a part of a lubricating oil passage for circulating the oil for lubricating the speed change mechanism in the case 10, the inflow of the oil into the hollow portion 30 is prevented by the supply side oil. The passage, that is, the oil passage 11a on the converter housing 11 side communicates with the output oil passage for the lubricating pressure without being opened into the case 10 on the way, so that the converter housing of the hollow portion 30 corresponding to the discharge portion of the oil passage 11a. The 11 side is closed by a plug 38 fitted in the hollow portion 30. Further, as described above, the opening of the hollow portion 30 on the case wall side has the case grooves 10a, 10b on the outer race outer peripheral side of the roller bearing 32 and the case groove 10a, 10b on the outer race outer side of the roller bearing 32 via the gap between the shaft end and the case side shaft end accommodating portion. The discharge side oil passage is formed by communicating with the space inside the case through the space between the bearing rollers and the gap between the counter driven gear 34 and the case wall.

From the lubricating oil passage structure of the counter shaft Y portion, the hollow portion 30 of the counter shaft 3 has
The oil in the pressurized state of the lubricating pressure is supplied from the oil passage 11a on the converter housing 11 side through the orifice of the plug 37 as shown by the arrow pointing left in FIG. 3, but the flow of this oil is blocked by the plug 38. Then, it does not enter the hollow portion 30 beyond it, but is used for lubrication of the thrust bearing 35 and the roller bearing 31, and is discharged from the gap between these bearings. On the other hand, the oil in the pressure released state flows from the gap between the case 10 and the counter driven gear 34 to the case groove 10a and the shaft end accommodating portion of the case 10 as shown by a downward arrow and a leftward arrow following the downward arrow in FIG. Through the gap between the end wall of the case 10 and the shaft end of the counter shaft 3. Since this oil flow is a flow through the gap, invasion of bubbles is hindered. In addition, oil that comes out of the hollow portion 30 of the counter shaft 3 from the gap between the end wall of the case 10 and the shaft end of the counter shaft 3 is stored in the shaft end housing portion of the case 10, the case groove 10b, the case 10 and the counter driven gear. It is discharged below the inner space of the case through the gap between 34.

When the counter shaft 3 rotates under such a supply / discharge condition of oil (the direction of rotation is indicated by a hatched arrow in FIG. 4), a centrifugal force due to the rotation is applied to the oil in the hollow portion 30. In operation, the oil is pressed toward the wall surface of the hollow portion 30 as indicated by the upward and downward arrows above and below the breather pipe 51 in FIG. By this action, the oil near the axis of the counter shaft 3 is removed to the outside, and the vicinity of the opening of the breather pipe 51 is in a state of only the air with the oil removed, and the air in the hollow portion 30 is discharged through the breather pipe 51. It is possible to prevent the oil from being sucked into the breather pipe 51 when a breathing action occurs.

Further, when the rotation of the counter shaft 3 is stopped, the rotation of all the rotating members of the speed change mechanism including the turbine output shaft of the torque converter is also stopped. Therefore, the oil pump driven by the rotation of the turbine output shaft also stops, and the output of the lubricating pressure using this as a hydraulic pressure source also disappears. Therefore, the oil supply from the oil passage 11a and the case 10 are also suppressed.
The oil does not flow down through the gap between the counter driven gear 34 and the counter driven gear 34. Even in this state, the oil continues to flow due to gravity, so that the oil remaining in the hollow portion 30 is
Shaft end housing of case 10, case groove 10b, and case 1
It is discharged below the space inside the case through the gap between 0 and the counter driven gear 34.

As described above in detail, in the breather device having such a configuration, the hollow portion 30 communicating with the space inside the case of the counter shaft 3 of the speed change mechanism serves as a breather chamber, so that the breather chamber is in operation during operation of the automatic transmission. Is a space that constantly rotates, and even if oil or its bubbles invade the space, the centrifugal force that acts on them causes the oil or its bubbles on the outer peripheral side of the hollow portion 30, as shown by the arrow in FIG. Since it is excluded on the outer peripheral side, it is possible to prevent oil from being sucked into the ventilation passage 51 that opens into the breather chamber. Therefore,
According to this breather device, due to the gas-liquid separation action by the rotation of the counter shaft 3, a lot of bubbles are generated due to the agitation of the oil in the case 10, and even when the space in the case is completely filled with bubbles, breathing is performed. It is possible to prevent the accompanying oil blowing. Moreover, in this embodiment, the opening is located at the axial center portion of the counter shaft 3 where the gas-liquid separating action is most prominent, so that it is possible to more surely prevent the oil blow associated with breathing.

Further, in the case of this embodiment, the breather device constituting the breather device is constituted by the breather pipe 51 including the opening in the case, so that the structure of the case can be greatly improved in the conventional transmission case. It also has the advantage of being applicable without modification. More specifically, referring to FIG. 2, for example, a breather hole is provided above the side cover 12 of the transmission case, and a breather plug P is screwed into the hole to form a breather device as shown by an imaginary line in the figure. If it is assumed that the side cover 12 covers the breather hole, the transmission case 10 may be modified by adding the fixing portion of the breather pipe 51.
Further, when the oil supply to the hollow portion 30 of the counter shaft 3 is forced lubrication, referring to FIG. 3, the amount of the oil supplied from the supply oil passage 11a by the orifice is supplied into the hollow portion 30. It is possible to make a fine change by replacing the plug with an orifice for distributing the bearings and the lubrication of both bearings 35 and 31 with the closing plug 38 as shown in the drawing.

Further, when the breather chamber is defined in the counter shaft 3 as in the present embodiment, as shown in the actual positional relationship in FIG. 2, the main shaft of the transmission mechanism (the center of the generally circular rear cover 13 shown in the drawing is shown). Represents the axial center position) and the differential shaft (which is placed at a lower position than the other shafts due to the connection with the axle), which is higher on the case (usually the highest position among the three axes) The breather chamber can be placed in the breather chamber, and thereby the gas-liquid separating action and the high level of the opening in the case of the breather pipe 51 have a synergistic effect, so that the oil blow associated with breathing can be prevented more reliably.

Also in the transmission in which the hollow portion 30 of the counter shaft 3 is used as the oil circulation path as in this embodiment, the supply oil passage is narrowed to prevent the oil from flowing into the hollow portion 30 in the counter shaft 3. The amount of oil in the breather chamber can be limited by restricting it with a clearance or a plug for this purpose, whereby the above-mentioned respective effects mainly including the gas-liquid separating action by the rotation of the counter shaft 3 can be obtained without any trouble. Further, by restricting the inflow of oil into the hollow portion 30 of the counter shaft 3 and constantly discharging the oil from the hollow portion 30, the amount of oil in the breather chamber defined by the hollow portion 30 can be regulated. Therefore, the breather chamber is not filled with oil, and the gas-liquid separating action by the rotation of the counter shaft 3 is always stable.

Although the present invention has been described with reference to the embodiments for the convenience of understanding of the technical idea, the present invention is not limited to the illustrated embodiments, and each of the claims is not limited thereto. Within the scope of the matters described in the claims, various concrete configurations can be changed and implemented. For example, in the illustrated embodiment, the case where the rotating member is the counter shaft 3 on the counter axis Y has been illustrated, but the gist of the present invention is to make the rotating space a breather chamber in a foamed state where oil is unlikely to enter. Therefore, it is possible to use a rotary member as an input shaft on the main axis X, or to use another rotary shaft on the main axis X to apply the shaft as a rotary member. Are included in the scope of the present invention.

[Brief description of drawings]

FIG. 1 is an axial cross-sectional view showing three axes of a horizontal type automatic transmission as an application target of the present invention developed on the same plane.

FIG. 2 is a front view of an automatic transmission to which the breather device according to the embodiment is applied, as seen in the axial direction from the rear cover side.

FIG. 3 is an enlarged cross-sectional view of a portion AA of FIG.

FIG. 4 is a front view showing a support portion of the counter shaft to the case as viewed from the inside of the case.

[Explanation of symbols]

3 Counter shaft (rotating member) 10 Automatic transmission case 11a Supply side oil passage 11b Discharge side oil passage 30 hollow 51 breather pipe

Continued front page    (72) Inventor Kazunori Takagi             10 Akane, Takane, Fujii-cho, Anjo City, Aichi Prefecture             N AW Co., Ltd. (72) Inventor Kazutaka Otsubo             10 Akane, Takane, Fujii-cho, Anjo City, Aichi Prefecture             N AW Co., Ltd. F term (reference) 3J063 AA01 AC04 BA13 CA01 CB44                       CD69 XG24 XG31 XG53

Claims (6)

[Claims] 1. A breather device for communicating a space inside a case of an automatic transmission to the outside air, wherein a hollow portion communicating with the space inside the case of a rotating member of a speed change mechanism is used as a breather chamber, and an air passage is provided which opens into the breather chamber. A breather device for an automatic transmission, which is characterized in that 2. The breather device for an automatic transmission according to claim 1, wherein the ventilation passage opens at a breather chamber at an axial center portion of the rotating member. 3. The breather passage is configured by a breather pipe that is separate from the case, and one end of the breather pipe is inserted into the hollow portion of the rotating member and opens in the breather chamber. Breather device for automatic transmission. 4. The breather device for an automatic transmission according to claim 1, 2 or 3, wherein the rotating member is a counter shaft of a transmission mechanism. 5. The hollow portion constitutes a part of a lubricating oil passage that circulates oil that lubricates a speed change mechanism in a case, and an inflow of oil into the hollow portion causes a supply-side oil passage to reach the hollow portion. The breather device for an automatic transmission according to any one of claims 1 to 4, wherein the breather device is restricted by the narrowing of the. 6. The hollow portion communicates with a discharge-side oil passage,
A breather device for an automatic transmission according to claim 5.