JP5434995B2 - Power transmission device - Google Patents

Description

  The present invention includes a transmission, a countershaft for transmitting power from the transmission, a differential mechanism for transmitting power from the countershaft to left and right drive wheels, a transmission, a differential mechanism, and a countershaft. The present invention relates to a power transmission device including a housing case.

  Conventionally, as this type of power transmission device, in order to eliminate the pressure difference between the inside and outside of the case due to the volume fluctuation of the hydraulic oil according to the temperature inside the case housing the transmission, the power is differentially transmitted from the output shaft of the transmission. It is known that a hollow portion of a countershaft for transmission to a mechanism is used as a breather chamber and has a ventilation path (breather plug) that opens in the breather chamber (see, for example, Patent Document 1). In this power transmission device, one opening of the breather chamber communicates with the inside of the case through a case groove for ventilation passing through the outer race outer peripheral side of the roller bearing that supports the countershaft, and the other breather chamber has the other opening. The opening is closed by a plug. In this power transmission device, the hydraulic oil is removed to the outer peripheral side of the breather chamber by the gas-liquid separation action by the centrifugal force generated with the rotation of the countershaft, so that the oil level in the case is increased. This prevents oil from being sucked into the air passage that opens into the breather chamber.

JP 2003-161362 A

  However, in the conventional power transmission device, depending on the posture of the power transmission device and the like, the ventilation case groove is blocked by the hydraulic oil scooped up by the counter driven gear fixed to the counter shaft, and the pressure in the case As the pressure rises, the hydraulic oil inside the case may flow into the breather chamber from the gap between the roller bearings. If the rotation of the countershaft decreases in such a state, the hydraulic oil cannot be removed to the outer peripheral side of the breather chamber due to the centrifugal force, and the hydraulic oil may be discharged out of the case through the air passage. There is.

  Therefore, the main purpose of the power transmission device of the present invention is to more reliably suppress oil from being discharged from the breather chamber of the countershaft through the breather plug.

  The power transmission device of the present invention employs the following means in order to achieve the main object.

The power transmission device of the present invention is
A transmission, a counter shaft for transmitting power from the transmission, a differential mechanism for transmitting power from the counter shaft to left and right drive wheels, the transmission, the differential mechanism, and the counter shaft A power transmission device comprising: a case that accommodates a breather plug that passes through the case and is disposed at one end of a breather chamber formed in the countershaft and that regulates the air pressure of the breather chamber;
The other end of the breather chamber is provided with a hydraulic oil inflow suppression wall that suppresses the inflow of hydraulic oil into the breather chamber, and the hydraulic oil inflow suppression wall is provided between the inside and outside of the breather chamber. A communication hole that allows air to flow is formed.

  In this power transmission device, even if the communication between one end of the breather chamber and the inside of the case is cut off by the hydraulic oil, the inside of the case is connected via the communication hole of the hydraulic oil inflow suppression wall provided at the other end of the breather chamber. And the breather chamber. As a result, it is possible to suppress an increase in the pressure inside the case, and to prevent the hydraulic oil from the inside of the case from flowing into the breather chamber.

  The breather chamber may be formed in the countershaft so as to extend coaxially with the countershaft, and may have an opening communicating with the inside of the case on the one end side. May be rotatably supported with respect to the case by a bearing lubricated with hydraulic oil, and the opening on the one end side of the breather chamber may communicate with the inside of the case via a communication path. The hydraulic oil inflow suppressing wall may be formed with a plurality of communication holes that allow air to flow between the inside and the outside of the breather chamber. Thereby, it can suppress that the pressure inside a case raises, and can suppress that the hydraulic fluid from the inside of a case flows in into a breather chamber through the clearance gap of a bearing. In addition, by forming a plurality of communication holes in the hydraulic oil inflow suppression wall, while ensuring the total opening area of the plurality of communication holes, the opening area of each communication hole is reduced, and the plurality of communication holes are interposed. It is possible to suppress the hydraulic oil from the inside of the case from flowing into the breather chamber. Therefore, according to this power transmission device, it is possible to more reliably suppress oil from being discharged from the breather chamber of the countershaft through the breather plug.

  Further, the plurality of communication holes may be formed closer to the axial center of the hydraulic oil inflow suppression wall than the outer periphery of the hydraulic oil inflow suppression wall. As a result, the hydraulic oil in the vicinity of the hydraulic oil inflow suppressing wall is moved away from the plurality of communication holes by the gas-liquid separation action due to the centrifugal force generated with the rotation of the countershaft, and the hydraulic oil from the inside of the case has the plurality of communication holes. The flow into the breather chamber can be suppressed.

  The total opening area of the plurality of communication holes may be greater than or equal to the opening area of the one end of the breather plug. Thereby, the communication between the breather chamber and the inside of the case can be ensured satisfactorily.

  Further, the breather chamber is formed in the inside of the case through the plurality of communication holes of the hydraulic oil inflow suppressing wall and a clearance of a bearing that is disposed on the other end side of the breather chamber and supports the counter shaft. It may be possible to communicate with. As a result, when the hydraulic fluid inside the case is shifted to one opening side of the breather chamber due to the change in posture of the power transmission device, the hydraulic fluid is supplied by the offset when the communication passage for ventilation is blocked. The breather chamber can be communicated with the inside of the case through the clearance gap of the bearing on the other end side where the decrease is made and the plurality of communication holes of the hydraulic oil inflow suppressing wall. As a result, it is possible to suppress an increase in the pressure inside the case, and to prevent the hydraulic oil from the inside of the case from flowing into the breather chamber through a bearing gap disposed on one opening side. It becomes.

  Further, the breather chamber may have an opening on the other end side, and the hydraulic oil inflow suppression wall may be defined by a plug disposed in the opening on the other end side of the breather chamber. In addition, the plurality of communication holes may be formed in the plug. Accordingly, the breather chamber and the inside of the case are communicated with each other through the plurality of communication holes formed in the plug while covering the opening on the other end side of the breather chamber and suppressing the inflow of hydraulic oil into the breather chamber. Can do.

  Furthermore, a through hole extending from the inner peripheral surface of the breather chamber to the outer peripheral surface of the counter shaft may be formed in the counter shaft. As a result, even if the hydraulic oil flows into the breather chamber, the hydraulic fluid that has flowed in is discharged out of the breather chamber through the through-hole due to the gas-liquid separation action caused by the centrifugal force generated with the rotation of the countershaft. Therefore, it is possible to more reliably suppress oil from being discharged from the breather chamber of the countershaft through the breather plug.

It is a schematic block diagram of the vehicle 10 carrying the power transmission device 20 which concerns on the Example of this invention. 3 is an enlarged cross-sectional view showing a main part of the power transmission device 20. FIG. 5 is a plan view showing a plug 57. FIG. 5 is a cross-sectional view showing a plug 57. FIG.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a schematic configuration diagram of a vehicle 10 equipped with a power transmission device 20 according to an embodiment of the present invention. As shown in the figure, the power transmission device 20 is mounted on a front wheel drive type vehicle 10 and transmits power from the engine 12 to the left and right drive wheels DW of the vehicle 10, and is a fluid transmission device (starting device). ) 22, an oil pump 30 as a hydraulic pressure generation source, a stepped automatic transmission (transmission device) 40, a gear mechanism 50 including a differential mechanism 45, and hydraulic fluid (ATF) from the oil pump 30 to adjust the fluid A hydraulic control device 70 supplied to the transmission device 22 and the automatic transmission 40, a transmission electronic control unit (not shown) that controls the hydraulic control device 70, and the like, a transmission case 21 (see FIG. 2) that accommodates these elements, and the like are included.

  The fluid transmission device 22 is configured as a fluid torque converter with a lock-up clutch, and an automatic transmission 40 via a pump impeller 23 connected to the crankshaft 14 of the engine 12 via a front cover and a turbine hub. A turbine runner 24 fixed to the input shaft 41, a stator 25 that rectifies the flow of hydraulic oil (ATF) from the turbine runner 24 to the pump impeller 23, a lockup clutch 26 having a damper mechanism (not shown), and the like.

  The oil pump 30 is configured as a so-called gear pump driven by power from the engine 12, and includes a pump assembly 33 including a pump body 31 and a pump cover 32 fixed to the transmission case 21, and an input shaft of the automatic transmission 40. An external gear 34 that is connected to the pump impeller 23 via a hollow hub 27 that extends coaxially with the shaft 41 and that is rotatably disposed in the pump body 31, and is eccentric to the external gear 34 in the pump body 31. And an internal gear 35 that meshes with the external gear 34. The oil pump 30 is stored in an oil pan (hydraulic oil storage unit) (not shown) via, for example, a suction oil passage formed in the pump body 31, a strainer (not shown), and the like by rotation of the external gear 34 and the internal gear 35. The hydraulic fluid thus drawn is sucked and the pressurized hydraulic fluid is discharged from a discharge port (not shown) and supplied to the hydraulic control device 70 via a discharge oil passage formed in the pump body 31, for example.

  The automatic transmission 40 has a plurality of planetary gear mechanisms and a plurality of friction engagement elements (clutch and brake), and the power transmitted to the input shaft 41 by changing the engagement state of the plurality of friction engagement elements. Can be shifted to a plurality of stages and output to an output shaft 42 extending coaxially with the input shaft 41. Note that hydraulic pressure is supplied from the hydraulic control device 70 to the plurality of friction engagement elements of the automatic transmission 40. Further, the automatic transmission 40 may have any shift speed such as 4th, 6th, or 8th.

  The gear mechanism 50 is fixed to one end side of a counter drive gear 51 fixed to the output shaft 42 of the automatic transmission 40 and a counter shaft 52 arranged parallel to the output shaft 42 and meshes with the counter drive gear 51. A counter-driven gear 53, a differential pinion gear (final drive gear) 54 fixed to the other end of the counter shaft 52, and a differential ring gear (final gear) that meshes with the differential pinion gear 54 and is fixed to the outer periphery of the differential case of the differential mechanism 45. Driven gear) 55. The drive mechanism DW is connected to the differential mechanism 45 via left and right shafts.

  FIG. 2 is an enlarged cross-sectional view showing a main part of the power transmission device 20. As shown in the figure, the counter shaft 52 is rotatably supported with respect to the transmission case 21 via a pair of tapered roller bearings (thrust bearings) 56a and 56b. The bearings 56 a and 56 b are disposed so that the large diameter side of the tapered roller is located on the axially central side of the counter shaft 52. A space 58a is defined between one end 52a (left end in FIG. 2) of the counter shaft 52 and the transmission case 21, and the other end 52b (right end in FIG. 2) of the counter shaft 52 is defined. A space 58b is defined between the transmission case 21 and the transmission case 21. Further, the transmission case 21 is formed with a communication path 21a so as to be positioned in the vicinity of the bearing 56a, that is, on the outer periphery on the upper side of the bearing 56a, and the communication path 21a is formed inside the transmission case 21, that is, in the automatic transmission 40 or the like. The accommodation space 210 in which the gear mechanism 50 and the like are accommodated communicates with the space 58a. However, the communication path 21a is not limited to the one formed in the transmission case 21, and may be formed on the outer periphery of the bearing 56a, for example, and uses a gap between the transmission case 21 and the bearing 56a. There may be.

  As shown in FIG. 2, the counter shaft 52 is formed in a hollow shape, and has a center hole (through hole) having a circular cross section extending coaxially with the counter shaft 52. In the embodiment, the central hole of the countershaft 52 is used as a breather chamber 520 for eliminating a pressure difference between the inside and outside of the case due to the volume fluctuation of the hydraulic oil according to the temperature in the transmission case 21 by so-called breathing action. . The central hole of the counter shaft 52, that is, the breather chamber 520 has an opening 520a on the end 52a side of the counter shaft 52 and an opening 520b on the end 52b side.

  One end of a breather plug (vent pipe) 60 fixed to the transmission case 21 is inserted into the opening 520 a of the breather chamber 520 of the counter shaft 52 so as to penetrate the transmission case 21. In the embodiment, the breather plug 60 is formed in a substantially L shape with resin or the like, and has an inner end 61 and an outer end 62 each having an opening. As shown in FIG. 2, the inner end 61 of the breather plug 60 is formed with a smaller diameter than the inner diameter of the breather chamber 520, and the breather chamber 520 extends so as to extend coaxially with the countershaft 52, that is, the breather chamber 520. It is inserted into the opening 520a. On the other hand, the outer end 62 of the breather plug 60 is connected to the other end of the hose 63 that is open to the atmosphere and fixed to the outer surface of the transmission case 21. Thereby, the breather chamber 520 communicates with the outside of the transmission case 21, that is, the atmosphere via the breather plug 60 and the hose 63, and the opening 520 a on the end 52 a side of the counter shaft 52, the counter shaft 52 and the transmission case 21. It communicates with the accommodation space 210 via the space 58a between them and the communication passage 21a formed in the transmission case 21.

  Further, a plug 57 as a hydraulic oil inflow suppression wall that suppresses the inflow of hydraulic oil into the breather chamber 520 is disposed on the countershaft 52 on the side of the opening 520 b of the breather chamber 520. FIG. 3 is a plan view showing the plug 57, and FIG. 4 is a cross-sectional view showing the plug 57. As shown in FIGS. 3 and 4, the plug 57 is formed as a bottomed cylindrical body made of metal or the like, and has a bottom portion 57a and a cylindrical tubular portion 57b extending from the bottom portion 57a. As shown in FIG. 3, the plug 57 is press-fitted into the opening 520b so that the bottom portion 57a is positioned on the left opening 520a side and the entire tubular portion 57b is accommodated in the breather chamber 520.・ Fixed. Thereby, the inflow of the hydraulic oil from the opening 520b side to the breather chamber 520 is suppressed.

  Further, as shown in FIGS. 3 and 4, a plurality of (two in the embodiment) circular communication holes 57 c are formed in the bottom portion 57 a of the plug 57 so as to be closer to the shaft center than the outer periphery of the plug 57. Yes. In the embodiment, the two circular communication holes 57 c are formed in the bottom portion 57 a so that their centers are separated from the central axis of the plug 57 by the same distance on the same diameter. Further, the opening area of each communication hole 57c is such that the total opening area of the plurality of communication holes 57c is inside the breather plug 60 within a range in which hydraulic oil can be prevented from flowing into the breather chamber 520 through each communication hole 57c. It is determined through experiments and analysis so as to be larger than the opening area of the end 61. By forming the plurality of communication holes 57c in the bottom portion 57a of the plug 57 in this manner, the opening area of each of the communication holes 57c is reduced while ensuring the total opening area of the plurality of communication holes 57c. The hydraulic oil from the inside of the case can be prevented from flowing into the breather chamber 520 through the hole 57c. Note that a single communication hole 57c may be formed at the bottom of the plug 57, or three or more communication holes 57c may be formed.

  Further, as shown in FIG. 2, the counter shaft 52 is formed with a through hole 521 extending from the inner peripheral surface of the breather chamber 520 to the outer peripheral surface of the counter shaft 52. As a result, even if hydraulic fluid flows into the breather chamber 520, the hydraulic fluid that has flowed in by the gas-liquid separation action due to the centrifugal force generated with the rotation of the countershaft 52 flows into the breather chamber 520 through the through hole 521. It can be discharged outside. As a result, it is possible to suppress oil from being discharged from the breather chamber 520 of the counter shaft 52 through the breather plug 60.

  In the vehicle 10 equipped with the power transmission device 20 configured as described above, when the power from the engine is transmitted to the counter shaft 52 and the differential mechanism 45 via the automatic transmission 40, the transmission case 21 The hydraulic oil stored in the bottom is scraped up by the differential ring gear 55 and the counter driven gear 53 and supplied to the bearings 56a and 56b, whereby the bearings 56a and 56b are lubricated and cooled. At this time, the hydraulic oil supplied to the bearings 56a and 56b is drawn into the gap between the bearings 56a and 56b by the rotation of the tapered rollers, and is then discharged again into the housing space 210. Therefore, the gap between the bearings 56a and 56b Basically, a small amount of hydraulic fluid flows into the spaces 58a, 58b, that is, the breather chamber 520 through the gaps between the tapered rollers and the outer and inner rings. Even if the hydraulic oil slightly flows into the breather chamber 520 from the spaces 58a and 58b, the hydraulic oil in the breather chamber 520 is caused to flow through the through-holes by the gas-liquid separation action caused by the centrifugal force generated with the rotation of the counter shaft 52. It can be discharged to the accommodation space 210 (outdoors) via 521.

  Further, the opening 520a on the bearing 56a side of the breather chamber 520 is formed in the accommodating space 210 via the space 58a defined by the countershaft 52 and the transmission case 21 and the communication passage 21a formed in the transmission case 21 as described above. And the outside of the transmission case 21, that is, the atmosphere via the breather plug 60 and the hose 63. As a result, when a pressure difference between the inside and outside of the case arises due to a change in the volume of hydraulic oil in accordance with the temperature inside the transmission case 21, air flows between the inside and outside of the case via the breather chamber 520 by a so-called breathing action. Thus, the pressure difference can be reduced. In the power transmission device 20 of the embodiment, when the working oil is properly supplied to the bearings 56a and 56b, the working oil is filled in the gap between the bearings 56a and 56b by the rotation of the tapered rollers, and the gap Therefore, air hardly flows into the breather chamber 520 from the opening 520b on the bearing 56b side.

  On the other hand, when the turning of the vehicle 10 equipped with the power transmission device 20 of the embodiment continues for a relatively long time, the posture of the power transmission device 20 is tilted, and the hydraulic oil at the bottom of the transmission case 21 is transferred to the counter shaft 52. May be shifted to the end 52a side (left side in FIG. 2). Further, when the posture of the power transmission device 20 is inclined, the suction port of the strainer (not shown) is partially exposed from the liquid level of the oil pan (not shown), and the working oil (including leakage oil) is sucked and discharged by the oil pump 30. As a result, the viscosity of the hydraulic oil (leakage oil) increases. In such a state, when a large amount of hydraulic oil is scooped up near the communication path 21a of the transmission case 21 by the counter driven gear 53, the communication path 21a is blocked by the hydraulic oil, and the opening 520a of the breather chamber 520 is formed. And communication with the inside of the transmission case 21, that is, the accommodation space 210 is cut off. However, when the hydraulic oil in the transmission case 21 is shifted to the end 52a side of the counter shaft 52 in this way, the operation to the bearing 56b disposed on the end 52b side (right side in FIG. 2) of the counter shaft 52 is performed. Since the amount of oil supplied decreases, air can pass through the gap between the bearings 56b. In the power transmission device 20 in the embodiment, a plurality of communication holes 57 c are formed in the plug 57 disposed in the opening 520 b of the breather chamber 520. Accordingly, the breather chamber 520 communicates with the interior of the transmission case 21, that is, the accommodation space 210 through the gaps between the plurality of communication holes 57 c of the plug 57, the space 58 b, and the bearing 56 b, and the breather plug 60 and the hose 63 on the opening 520 a side. It communicates with the outside of the transmission case 21, that is, the atmosphere via

  As a result, even if the communication passage 21a is blocked due to the hydraulic oil at the bottom of the transmission case 21 being shifted to the end 52a side of the countershaft 52 due to the change in posture of the power transmission device 20, the transmission case 21 is closed. When a pressure difference between the inside and outside of the case arises due to the volume fluctuation of the hydraulic oil according to the inside temperature, air flows between the inside and outside of the case through the breather chamber 520 by a so-called breathing action. Can be reduced. As a result, an increase in pressure in the transmission case 21, that is, the accommodation space 210 can be suppressed, so that hydraulic oil from the accommodation space 210 flows into the space 58a, that is, the breather chamber 520 through the gap of the bearing 56a. It is possible to suppress the oil from being discharged from the breather chamber 520 through the breather plug 60. Particularly, as the rotational speed of the counter shaft 52 decreases, the rotational speed of the bearing 56a decreases, the action of discharging the hydraulic oil from the clearance of the bearing 56a to the accommodating space 210 is weakened, and the hydraulic oil flows into the space 58a side. Even if it becomes easy, it becomes possible to satisfactorily suppress the hydraulic oil from flowing into the breather chamber 520 (space 58a), and to prevent the oil from being discharged from the breather chamber 520 through the breather plug 60. .

  When the hydraulic oil at the bottom of the transmission case 21 is shifted to the end 52b side of the countershaft 52 due to a change in the posture of the power transmission device 20, the transmission case 21 (accommodating space 210) basically passes through the communication path 21a. ) And the breather chamber 520 are ensured. Therefore, in such a case, even if a pressure difference between the inside and outside of the case arises due to a change in the volume of the hydraulic oil according to the temperature inside the transmission case 21, the air between the inside and outside of the case via the breather chamber 520 is generated by the so-called breathing action. Circulates, the pressure difference can be reduced. Even if the hydraulic fluid flows into the cylindrical portion 57b of the plug 57 due to the hydraulic fluid at the bottom of the transmission case 21 being offset toward the end 52b of the countershaft 52, the countershaft 52 rotates. The hydraulic fluid near the plug 57 can be moved away from the plurality of communication holes 57c near the shaft center by the gas-liquid separation action caused by the centrifugal force generated in this manner. Therefore, in the power transmission device 20 of the embodiment, the hydraulic oil can be satisfactorily suppressed from flowing into the breather chamber 520 through the plurality of communication holes 57c.

  As described above, in the power transmission device 20 according to the embodiment, one end of the breather chamber 520 of the countershaft 52 (one end portion 52a of the countershaft 52) communicates with the inside of the transmission case 21 (the accommodation space 210). 520a is formed, and a plug 57 that defines a hydraulic oil inflow suppression wall that suppresses the flow of hydraulic oil into the breather chamber 520 is disposed at the other end of the breather chamber 520 (the other end 52b of the countershaft 52). The The plug 57 is formed with a communication hole 57 c that allows air to flow (inflow and outflow) between the accommodation space 210 of the transmission case 21 and the breather chamber 520.

  Thereby, even if the communication between the one opening 520a of the breather chamber 520 and the accommodation space 210 of the transmission case 21 is cut off by the hydraulic oil, the communication hole 57c of the plug 57 disposed at the other end of the breather chamber 520 is used. Thus, air can be exchanged between the accommodation space 210 of the transmission case 21 and the breather chamber 520. As a result, it is possible to suppress the pressure in the accommodation space 210 of the transmission case 21 from increasing, and to prevent the hydraulic oil from the accommodation space 210 of the transmission case 21 from flowing into the breather chamber 520.

  In the above-described embodiment, both end portions 52a and 52b of the counter shaft 52 are rotatably supported with respect to the transmission case 21 by bearings 56a and 56b lubricated with hydraulic oil, and are arranged on one end side of the breather chamber 520. The opening 520a communicates with the accommodation space 210 of the transmission case 21 via a communication passage 21a formed in the transmission case 21, and the plug 57 has air between the accommodation space 210 of the transmission case 21 and the breather chamber 520. A plurality of communication holes 57c that allow the flow (inflow and outflow) are formed. As a result, when the ventilation communication passage 21a that communicates between the breather chamber 520 and the accommodation space 210 of the transmission case 21 is closed by the hydraulic oil, a plurality of plastics 57 provided at the other end of the breather chamber 520 are provided. Air can be exchanged between the accommodation space 210 of the transmission case 21 and the breather chamber 520 through the communication hole 57c. As a result, an increase in pressure in the accommodation space 210 of the transmission case 21 is suppressed, and hydraulic oil from the accommodation space 210 of the transmission case 21 is suppressed from flowing into the breather chamber 520 through the gap of the bearing 56a. It becomes possible. Further, by forming a plurality of communication holes 57c in the plug 57, the total opening area of the plurality of communication holes 57c is ensured, and the opening area of each communication hole 57c is reduced, and the plurality of communication holes 57c are interposed. Thus, it is possible to suppress the hydraulic oil from the accommodation space 210 of the transmission case 21 from flowing into the breather chamber 520. Therefore, according to the power transmission device 20 of the embodiment, it is possible to more reliably suppress oil from being discharged from the breather chamber 520 of the counter shaft 52 through the breather plug 60.

  Further, in the above embodiment, the plurality of communication holes 57 c are formed closer to the axial center of the plug 57 than the outer periphery of the plug 57. As a result, the hydraulic fluid in the vicinity of the plug 57 is moved away from the plurality of communication holes 57c by the gas-liquid separation action due to the centrifugal force generated with the rotation of the counter shaft 52, and a plurality of hydraulic fluids are received from the accommodation space 210 of the transmission case 21. It is possible to suppress the flow into the breather chamber 520 through the communication hole 57c.

  Further, in the above embodiment, the total opening area of each communication hole 57c is the total opening area of the plurality of communication holes 57c within a range in which the hydraulic oil can be prevented from flowing into the breather chamber 520 through each communication hole 57c. Is set to be equal to or larger than the opening area of the inner end 61 of the breather plug 60. Accordingly, the hydraulic oil from the accommodation space 210 of the transmission case 21 can be better suppressed from flowing into the breather chamber 520 through the plurality of communication holes 57c, and the breather chamber 520 and the accommodation space 210 of the transmission case 21 Can be secured satisfactorily.

  Further, in the above-described embodiment, the breather chamber 520 can communicate with the inside of the transmission case 21 through a plurality of communication holes 57c of the plug 57 and the clearance of the bearing 56b disposed on the other opening 520b side of the breather chamber 520. It is. That is, the attitude of the power transmission device 20 is tilted due to turning of the vehicle and the working oil in the accommodation space 210 of the transmission case 21 is shifted to the one opening 520a side of the breather chamber 520, thereby causing the communication passage 21a for ventilation. Is closed, the breather chamber 520 is accommodated in the transmission case 21 via the clearance of the bearing 56b disposed on the other opening 520b side where the supply of hydraulic oil is reduced due to the deviation, the plurality of communication holes 57c of the plug 57, and the like. Communication with the space 210 is possible. Thereby, the rise in the pressure of the accommodation space 210 of the transmission case 21 is suppressed, and the hydraulic oil from the accommodation space 210 of the transmission case 21 passes through the clearance of the bearing 56a disposed on the one opening 520a side, and the breather chamber 520. It is possible to suppress the flow into the water. However, in the power transmission device 20 described above, a communication path that allows the space 58b and the accommodation space 210 of the transmission case 21 to communicate with each other is separately formed in the transmission case 21, and the plurality of communication holes 57c, the space 58b, and the formed communication path are formed. The breather chamber 520 and the accommodation space 210 of the transmission case 21 may be communicated with each other.

  Further, in the above-described embodiment, the breather chamber 520 has an opening 520b on the other end side, and hydraulic oil inflow suppression that suppresses the inflow of hydraulic oil into the breather chamber 520 by the bottom portion 57a of the plug 57 disposed in the opening 520b. A wall is defined, and a plurality of communication holes 57 c are formed in the plug 57. Accordingly, the breather chamber 520 and the transmission case are connected via the plurality of communication holes 57c formed in the plug 57 while covering the opening 520b on the other end side of the breather chamber 520 and suppressing the inflow of hydraulic oil into the breather chamber 420. 21 accommodation spaces 210 can be communicated with each other. However, if the hydraulic oil inflow suppression wall that suppresses the inflow of hydraulic oil into the breather chamber 520 has a plurality of communication holes and can suppress the inflow of hydraulic oil into the breather chamber 520, it is defined by the plug 57. It is not limited to what is done. For example, by not forming the opening 520b communicating with the breather chamber 520 at the end 52b of the counter shaft 52, a hydraulic oil inflow suppression wall that suppresses the inflow of hydraulic oil is formed on the other end side of the counter shaft 52, and A plurality of communication holes may be formed in the hydraulic oil inflow suppression wall.

  In the above embodiment, the counter shaft 52 is formed with a through hole 521 extending from the inner peripheral surface of the breather chamber 520 to the outer peripheral surface of the counter shaft 52. As a result, even if hydraulic fluid flows into the breather chamber 520, the hydraulic fluid that has flowed in by the gas-liquid separation action due to the centrifugal force generated with the rotation of the countershaft 52 flows into the breather chamber 520 through the through hole 521. Since the oil can be discharged to the outside, it is possible to further reliably prevent the oil from being discharged from the breather chamber 520 of the counter shaft 52 through the breather plug 60.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above embodiment, the automatic transmission 40 (transmission device), the counter shaft 52 for transmitting power from the automatic transmission 40, and the difference for transmitting power from the counter shaft 52 to the left and right drive wheels DW. The transmission mechanism 45, the automatic transmission 40, the differential mechanism 45, and the transmission shaft 21 that accommodates the countershaft 52, and the breather chamber 520 that passes through the transmission case 21 and is formed in the countershaft 52 are disposed at one end. The power transmission device 20 including the breather plug 60 that regulates the air pressure of the breather chamber 520 corresponds to a “power transmission device”, and the bottom portion 57 a of the plug 57 disposed at the other end of the breather chamber 520 is the breather chamber 520. It corresponds to a “hydraulic oil inflow suppression wall” that suppresses the inflow of hydraulic oil to the tank. However, the correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is described in the column of means for the embodiment etc. to solve the problem. The embodiment for carrying out the invention is an example for specifically explaining the embodiment, and does not limit the elements of the invention described in the column of means for solving the problem. In other words, the examples and the like are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is not limited to that column. This should be done based on the description.

  As mentioned above, although the embodiment of the present invention has been described using examples, the present invention is not limited to the above-described examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the power transmission device manufacturing industry.

  DESCRIPTION OF SYMBOLS 10 Vehicle, 12 Engine, 14 Crankshaft, 20 Power transmission device, 21 Transmission case, 21a Communication path, 22 Fluid transmission device, 23 Pump impeller, 24 Turbine runner, 25 Stator, 26 Lock-up clutch, 27 Hub, 30 Oil pump , 31 Pump body, 32 Pump cover, 33 Pump assembly, 34 External gear, 35 Internal gear, 40 Automatic transmission, 41 Input shaft, 42 Output shaft, 45 Differential mechanism, 50 Gear mechanism, 51 Counter drive gear, 52 counter shaft, 52a, 52b end, 53 counter driven gear, 54 differential pinion gear, 55 differential ring gear, 56a, 56b bearing, 57 plug, 57a bottom, 57b cylindrical portion, 57c communication hole 58a, 58b space, 60 a breather plug (vent tube) 61 inner end, 62 outer end 63 hose 70 hydraulic control device 210 housing space, 520 breather chamber, 520a, 520b open, 521 through-hole.

Claims (7)

A transmission, a counter shaft for transmitting power from the transmission, a differential mechanism for transmitting power from the counter shaft to left and right drive wheels, the transmission, the differential mechanism, and the counter shaft A power transmission device comprising: a case that accommodates a breather plug that passes through the case and is disposed at one end of a breather chamber formed in the countershaft and that regulates the air pressure of the breather chamber;
The other end of the breather chamber is provided with a hydraulic oil inflow suppression wall that suppresses the inflow of hydraulic oil into the breather chamber, and the hydraulic oil inflow suppression wall is provided between the inside and outside of the breather chamber. A power transmission device, characterized in that a communication hole that allows air to flow is formed. The power transmission device according to claim 1,
The breather chamber is formed in the countershaft so as to extend coaxially with the countershaft, and has an opening communicating with the inside of the case on the one end side.
Both ends of the countershaft are rotatably supported with respect to the case by bearings lubricated with hydraulic oil,
The opening on the one end side of the breather chamber communicates with the inside of the case through a communication path,
The power transmission device according to claim 1, wherein the hydraulic oil inflow suppressing wall has a plurality of communication holes that allow air to flow between the inside and the outside of the breather chamber. The power transmission device according to claim 2,
The plurality of communication holes are formed closer to the axial center of the hydraulic oil inflow suppression wall than the outer periphery of the hydraulic oil inflow suppression wall. In the power transmission device according to claim 2 or 3,
The power transmission device, wherein a total opening area of the plurality of communication holes is equal to or larger than an opening area of the one end of the breather plug. In the power transmission device according to any one of claims 2 to 4,
The breather chamber communicates with the interior of the case via the plurality of communication holes of the hydraulic oil inflow suppression wall and a clearance of a bearing that is disposed on the other end side of the breather chamber and supports the counter shaft. A power transmission device characterized in that it is possible. In the power transmission device according to any one of claims 2 to 5,
The breather chamber has an opening on the other end side,
The hydraulic oil inflow suppressing wall is defined by a plug disposed in the opening on the other end side of the breather chamber, and the plug is formed with the plurality of communication holes. Transmission device. In the power transmission device according to any one of claims 1 to 6,
The countershaft is provided with a through hole extending from an inner peripheral surface of the breather chamber to an outer peripheral surface of the countershaft.

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