JP2015086935A - Breather structure of power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breather structure of a power transmission device which can prevent oil from blowing out of a breather chamber.SOLUTION: In a breather structure, the volume of a transmission side breather chamber 29 is formed to be larger than that of a clutch housing side breather chamber 28. In a bottom wall 32 of the clutch housing side breather chamber 28, an air introduction hole 36 in communication with the inside of a transaxle case 7 is formed. In an upper wall 33 of the transmission side breather chamber 29, an air discharge hole 37 in communication with the exterior is formed.

Description

  The present invention relates to a breather structure of a power transmission device, and more particularly to a breather structure of a power transmission device having a breather chamber for reducing pressure fluctuations inside a main body case.

  A power transmission device mounted on a vehicle such as an automobile includes a main body case that houses a clutch that interrupts the power of an engine and a speed change mechanism that includes a rotating shaft and gears. It has a breather structure for adjusting temperature and pressure. As a breather structure of a conventional power transmission device, for example, the one described in Patent Document 1 is known.

  The breather structure of this power transmission device is such that the partition wall forming the air breather chamber is suspended from the corner of the main body case in a curved shape to increase the volume of the air breather chamber, and at the upper part of the partition wall. An oil inlet is formed.

  An oil outlet wider than the oil inlet that discharges oil that has entered the air breather chamber is formed on the lower end side of the partition wall, and an air breather pipe that discharges air in the air breather chamber to the outside is formed immediately above the oil outlet.

Japanese Patent Laid-Open No. 11-303975

  However, in such a breather structure of the conventional power transmission device, since the air breather chamber is formed at the corner portion of the main body case, there is a limit to increasing the volume of the air breather chamber, and the volume of the air breather chamber is limited. It was difficult to enlarge.

  For this reason, the distance between the oil inlet and the air breather pipe is shortened, so that the oil that has entered the air breather chamber from the oil inlet can easily flow into the air breather pipe, and the oil that has entered the air breather chamber passes through the air breather pipe to the outside. There is a risk of blowing out.

  In addition, since the air breather pipe is formed immediately above the oil outlet, the oil that has entered the air breather chamber from the lower side of the oil outlet may blow out to the outside through the air breather pipe.

  The present invention has been made paying attention to the above-mentioned problems, and an object thereof is to provide a breather structure of a power transmission device capable of preventing oil from being blown out from a breather chamber. It is.

  According to a first aspect of the present invention, there is provided an input shaft that is rotated by power of an internal combustion engine, a transmission gear provided on the input shaft, or a counter shaft to which rotation of the input shaft is transmitted via a reverse idler gear that is separate from the transmission gear. , And a final gear that transmits power from the counter shaft and performs forward rotation that is rotation when the vehicle moves forward and reverse rotation that is rotation when the vehicle moves backward, and the oil stored in the bottom portion is used as a final gear or A main body case including a transmission case configured to be scraped up by a reverse idler gear and a clutch housing in which a clutch mechanism is accommodated, and an upper main body case with respect to the final gear and the reverse idler gear, A breather structure of a power transmission device in which a breather chamber partitioned from the inside of the main body case is formed, The breather chamber is formed on an upper facing surface of the cucci housing facing the transmission case, and is surrounded by an upper wall, a side wall and a bottom wall, and a breather chamber on the clutch housing side, and an upper portion of the transmission case facing the clutch housing. A transmission-side breather chamber formed on the opposing surface and surrounded by an upper wall, a side wall, and a bottom wall. The transmission-side breather chamber has a larger volume than the clutch housing-side breather chamber. An air introduction hole that communicates with the inside of the main body case is formed on the bottom wall of the breather chamber, and an air discharge hole that communicates with the outside is formed on the top wall of the transmission-side breather chamber.

As a second aspect of the present invention, the bottom wall of the transmission case side breather chamber may be inclined so as to gradually decrease from the air discharge hole toward the air introduction hole in the height direction of the main body case.
As a third aspect of the present invention, the air introduction hole is formed with respect to the front air introduction hole formed in front of the oil scattering direction scraped up by the final gear during the forward rotation of the final gear, and the front air introduction hole. A rear air introduction hole positioned rearward in the scattering direction and above the front air introduction hole, and the front air introduction hole and the rear air introduction hole are formed in the bottom wall of the breather chamber on the clutch housing side. A vertical rib protruding downward from a virtual plane connecting the front air introduction hole and the rear air introduction hole may be formed.

  As a fourth aspect of the present invention, the input shaft, the reverse idler gear rotation shaft, and the final gear rotation shaft are arranged in parallel, and the input shaft is connected to the reverse idler gear, the counter shaft and the final gear in the breather chamber. When the clutch housing is viewed from the axial direction of the input shaft, the bottom wall of the breather chamber on the clutch housing side is located in front of the front air introduction hole and from the front air introduction hole. You may comprise including the front side bottom wall which inclines toward the front upper direction of a scattering direction, and the rear side bottom wall which inclines toward the back upper direction of a scattering direction rather than a rear side air introduction hole.

As a fifth aspect of the present invention, when the clutch housing is viewed from the axial direction of the final gear, the bottom wall of the clutch housing side breather chamber is located between the front air introduction hole and the rear air introduction hole. The intermediate bottom wall may be formed on the intermediate bottom wall so as to extend vertically downward from the lower surface of the intermediate bottom wall from the lower surface of the intermediate bottom wall.
As a sixth aspect of the present invention, the vertical rib may be formed at the end of the intermediate bottom wall on the front air introduction hole side.

  As a seventh aspect of the present invention, a first boss portion for mounting the first speed change member is formed below the lower end side in the inclination direction of the front bottom wall, and the upper end side in the inclination direction of the rear bottom wall is formed. A second boss portion for mounting the second speed change member is formed below, the vertical rib is disposed between the first boss portion and the second boss portion, and the lower end of the vertical rib is the first boss portion. You may be located on the virtual plane between boss | hubs which tied the central axis of 1 boss | hub part, and the central axis of the 2nd boss | hub part.

  As an eighth aspect of the present invention, when the clutch housing is viewed from the axial direction of the input shaft, the lower side of the front air introduction hole is covered by the first boss portion, and the horizontal direction relative to the axial direction of the input shaft When viewed from a direction orthogonal to the second boss portion, the second boss portion and the rear air introduction hole may be arranged so as to overlap in the horizontal direction.

  As a ninth aspect of the present invention, the lower end in the inclination direction of the rear bottom wall is installed directly above the bearing portion that rotatably supports the axial end of the input shaft on the clutch housing, A reinforcing rib extending from the lower end in the inclination direction of the rear bottom wall to the bearing portion may be provided, and the oil introduction portion may be formed in the bearing portion rearward in the scattering direction with respect to the reinforcing rib.

  Thus, according to the first aspect described above, the volume of the transmission-side breather chamber is formed larger than the volume of the clutch housing-side breather chamber, and the bottom wall of the clutch housing-side breather chamber communicates with the inside of the main body case. Since the air introduction hole is formed and the air discharge hole communicating with the outside is formed in the upper wall of the transmission-side breather chamber, the distance from the air introduction hole to the air discharge hole can be increased.

  For this reason, when oil scraped up above the main body case by rotation of the final gear or reverse idler gear enters the breather chamber from the air introduction hole, it may be difficult to reach the air discharge hole from the air introduction hole. It is possible to prevent the oil from blowing out from the breather chamber through the air discharge hole.

  According to the second aspect, the bottom wall of the transmission case side breather chamber is inclined so as to gradually become lower from the air discharge hole toward the air introduction hole in the height direction of the main body case. When oil scooped up by the rotation of the gear or reverse idler gear enters the breather chamber from the air introduction hole and then flows into the breather chamber on the transmission side, the oil is aired by the inclined surface of the bottom wall. It can be made more difficult to reach by the discharge hole. For this reason, it is possible to prevent oil from staying in the vicinity of the air discharge hole, and it is possible to more effectively prevent the oil from blowing out from the breather chamber through the air discharge hole.

  According to said 3rd aspect, the virtual which connected the front side air introduction hole and the back side air introduction hole to the bottom wall of the clutch housing side breather chamber between the front side air introduction hole and the rear side air introduction hole A vertical rib that protrudes downward from the plane is formed, so that when oil that has been scraped up by the final gear that rotates forward when the vehicle moves forward enters the rear air introduction hole, the position is lower than the rear air introduction hole. It can be returned to the transmission case after flowing into the front air introduction hole formed in the above.

  Further, oil that is scraped up by a final gear that rotates forward when the vehicle moves forward and flows from below the rear air introduction hole to below the front air introduction hole collides with the vertical rib, so that the oil is introduced into the front air introduction hole. Can be prevented from entering the breather chamber from the front air introduction hole.

  Also, when the vehicle is moving backward, the oil that is scraped up by the reverse rotation of the final gear or the rotation of the reverse idler gear and flows from the lower side of the front air introduction hole to the rear air introduction hole collides with the vertical rib, and the oil is Intrusion into the side air introduction hole can be prevented, and entry into the breather chamber from the rear air introduction hole can be made difficult.

  As a result, the amount of oil that enters the breather chamber can be reduced, and oil can be more effectively prevented from blowing out from the breather chamber through the air discharge hole.

  According to the above fourth aspect, when the clutch housing is viewed from the axial direction of the input shaft, the bottom wall of the breather chamber on the clutch housing side is located in front of the front air introduction hole and is away from the front air introduction hole. Since it has a front bottom wall that inclines toward the front upper side in the scattering direction, the front air is introduced along the inclined surface of the front bottom wall with the oil scraped up by the reverse rotation of the final gear or the rotation of the reverse idler gear when the vehicle moves backward It can be guided below the hole. For this reason, it is possible to make it difficult for oil to enter the front air introduction hole.

  Further, when the clutch housing is viewed from the axial direction of the input shaft, the bottom wall of the breather chamber side of the clutch housing has a rear bottom wall that is inclined rearward and upward in the scattering direction from the rear air introduction hole. The oil scraped up by the forward rotation of the final gear when the vehicle moves forward can be guided below the rear air introduction hole along the inclined surface of the rear bottom wall. For this reason, it is possible to make it difficult for oil to enter the rear air introduction hole.

  According to the fifth aspect, when the clutch housing is viewed from the axial direction of the final gear, the bottom wall of the clutch housing side breather chamber is located between the front air introduction hole and the rear air introduction hole. The intermediate bottom wall is formed along the virtual plane, and the vertical rib is formed on the intermediate bottom wall so as to extend vertically downward from the lower surface of the intermediate bottom wall. Oil that is scraped up by forward rotation and flows from the rear air introduction hole toward the front air introduction hole below the breather chamber can be blocked by the intermediate bottom wall and the vertical rib, and the rear side below the breather chamber It is possible to prevent the air from flowing from the air introduction hole toward the front air introduction hole. For this reason, oil can be prevented from entering the breather chamber from the front air introduction hole.

  In the sixth aspect, when the oil enters the breather chamber from the rear air introduction hole, it tends to flow to the front air introduction hole formed at a position lower than the rear air introduction hole. When a large amount of oil enters the front air introduction hole, the oil tends to stay in the breather chamber.

  On the other hand, according to the sixth aspect, since the vertical rib is formed at the end of the intermediate bottom wall on the front air introduction hole side, the space below the front air introduction hole is used as the installation space for the vertical rib. Therefore, it is possible to suppress the intrusion of a large amount of oil into the front air introduction hole.

  According to the seventh aspect, since the first boss portion for mounting the first speed change member is formed below the lower end of the front bottom wall in the inclination direction, the front bottom wall and the first boss are formed. The space below the front bottom wall can be reduced by the portion. For this reason, the oil which penetrates into the front air introduction hole through the gap between the front bottom wall and the first boss portion can be reduced.

  Further, since the second boss portion for mounting the second transmission member is formed below the upper end side in the inclination direction of the rear bottom wall, the rear air is formed by the rear bottom wall and the second boss portion. The space below the introduction hole can be reduced. For this reason, the oil which penetrates into the rear air introduction hole through the gap between the rear bottom wall and the second boss portion can be reduced.

Further, the vertical rib is disposed between the first boss portion and the second boss portion, and the lower end of the vertical rib connects the central axis of the first boss portion and the central axis of the second boss portion. Since it is located on the virtual plane between the bosses, the oil flowing into the front air introduction hole through the gap between the front bottom wall and the first boss part and the gap between the rear bottom wall and the second boss part Oil that has flowed into the rear air introduction hole through can be made to collide with the vertical ribs, and oil that collided with the vertical wall can be guided below the transmission case.
As a result, it is possible to make it difficult for oil to enter the breather chamber, and it is possible to more effectively prevent the oil from blowing out from the breather chamber through the air discharge hole.

  According to the eighth aspect, when the clutch housing is viewed from the axial direction of the input shaft, the lower side of the front air introduction hole is covered by the first boss portion. Alternatively, it is possible to prevent the oil scooped up by the final gear rotating in the reverse direction from colliding with the first boss portion and directly entering the front air introduction hole.

  In addition, when viewed from the direction perpendicular to the horizontal direction with respect to the axial direction of the input shaft, the second boss portion and the rear air introduction hole are arranged so as to overlap in the horizontal direction. It is possible to prevent the oil scooped up by the rotating final gear from colliding with the second boss portion and directly entering the rear air introduction hole.

  According to the ninth aspect, the lower end of the rear bottom wall in the inclined direction is installed directly above the bearing portion that rotatably supports the axial end of the input shaft on the clutch housing, A reinforcing rib that extends from the lower end of the rear bottom wall in the direction of inclination to the bearing is provided, and the oil introduction part is formed in the bearing in the rear of the scattering direction with respect to the reinforcing rib. The oil flowing along the side bottom wall can be guided to the lower side of the transmission case along the reinforcing rib from the lower end in the inclination direction of the rear bottom wall. For this reason, it is possible to keep the oil away from the rear air introduction hole and make it difficult for the oil to enter the rear air introduction hole, and it is possible to prevent the oil from entering the breather chamber more effectively.

  Moreover, the oil guided below the transmission case along the reinforcing rib can be supplied to the bearing portion through the oil introducing portion, and the lubrication performance of the bearing portion can be improved.

FIG. 1 is a diagram showing an embodiment of a breather structure of a power transmission device of the present invention, and is a plan view of the power transmission device. 2 is a view showing an embodiment of a breather structure of the power transmission device of the present invention, and is a view taken in the direction of arrows V1-V1 in FIG. FIG. 3 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is a view taken in the direction of arrows V1-V1 in FIG. 1 with the reverse lever and shift fork removed. FIG. 4 is a diagram showing an embodiment of the breather structure of the power transmission device of the present invention, and is a plan view of the speed change mechanism with the transmission case removed. FIG. 5 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is a view taken in the direction of arrow V3 in FIG. FIG. 6 is a view showing an embodiment of a breather structure of the power transmission device of the present invention, and is a cross-sectional view taken in the direction of arrows V2-V2 in FIG. FIG. 7 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is an enlarged view around the breather chamber. FIG. 8 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is an enlarged sectional view around the breather chamber with the reverse lever and shift fork removed. FIG. 9 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is a view taken in the direction of arrows V1-V1 in FIG. 1 with the reverse lever and shift fork removed, and shows the flow of oil. FIG. FIG. 10 is a view showing an embodiment of the breather structure of the power transmission device of the present invention, and is an enlarged cross-sectional view around the breather chamber with the reverse lever and shift fork removed, showing the flow of oil. is there.

Embodiments of a breather structure for a power transmission device according to the present invention will be described below with reference to the drawings.
FIGS. 1-10 is a figure which shows the breather structure of the power transmission device of one Embodiment which concerns on this invention.

First, the configuration will be described.
In FIG. 1, a vehicle 1 includes an engine 2 as an internal combustion engine and a power transmission device 3 connected to the engine 2, and the output of the engine 2 is not shown through the power transmission device 3. Is transmitted to.

  The power transmission device 3 is provided to a clutch housing 4 that accommodates a clutch (not shown) that transmits power from a crankshaft (not shown) of the engine 2, and can be connected to and separated from the clutch, and the power of the engine 2 is transmitted via the clutch. A transmission case 6 that accommodates the transmission mechanism 5 (see FIGS. 4 and 5). The clutch housing 4 and the transmission case 6 constitute a transaxle case 7 as a main body case.

  In FIG. 2, the speed change mechanism 5 includes an input shaft 8 connected to a crankshaft via a clutch, a counter shaft 9 having a rotation shaft parallel to the input shaft 8, and a reverse idler shaft 10. The input shaft 8 is located above the counter shaft 9 and the reverse idler shaft 10, and the counter shaft 9 is located on the lower right side in FIG. Further, the reverse idler shaft 10 is located on the lower left side in FIG.

  As shown in FIGS. 4 and 5, the input shaft 8 is provided with a plurality of transmission gears 11. The transmission gear 11 has a first speed gear 11 </ b> A located on the engine 2 side, and is axially extended from the engine 2. As the distance increases, a second gear 11B, a third gear 11C, a fourth gear 11D, and a fifth gear 11E are sequentially provided. Further, the first speed gear 11A and the second speed gear 11B are fixed to the input shaft 8, and the third speed gear 11C, the fourth speed gear 11D, and the fifth speed gear 11E are rotatably provided with respect to the input shaft 8.

  The counter shaft 9 is provided with a plurality of speed change gears 12. The speed change gear 12 is provided with a first speed gear 12A on the engine 2 side, and the second speed gears 12B, 3B, 3 as the distance from the engine 2 in the axial direction increases. A speed gear 12C, a fourth speed gear 12D, and a fifth speed gear 12E are sequentially provided. The speed change gears 12 constituting the respective speed stages are meshed with the speed change gears constituting the same speed change stages of the speed change gear 11, and the first speed gear 12A and the second speed gear 12B are rotatably provided on the counter shaft 9. In addition, a third speed gear 12C, a fourth speed gear 12D, and a fifth speed gear 12E are fixed to the counter shaft 9.

  The reverse idler shaft 10 is provided with a reverse idler gear 13. The reverse idler gear 13 is provided so as to be movable in the axial direction of the reverse idler shaft 10, and a part of the transmission gear 11 provided on the input shaft 8. Can be meshed with the reverse input gear 11F.

  When the vehicle 1 moves backward, the reverse idler gear 13 meshes with the reverse input gear 11F, and the rotation of the input shaft 8 is transmitted to the reverse output gear 12F of the counter shaft 9 via the reverse input gear 11F. Can be converted into a reverse rotation direction opposite to the forward rotation direction, which is the rotation direction during forward movement.

  A final drive gear (not shown) constituting a part of the transmission gear 11 is fixed to the end of the counter shaft 9 on the engine 2 side. The final drive gear includes a large-diameter final gear 14. Are engaged (see FIGS. 2 and 3). The final gear 14 is fixed to a differential case of a differential device (not shown), and the rotation of the final gear 14 is transmitted to the left and right drive wheels via the differential device.

  That is, the transaxle case 7 of the present embodiment is input via the input shaft 8 that is rotated by the power of the engine 2 and the transmission gear 11 provided on the input shaft 8 or the reverse idler gear 13 that is separate from the transmission gear 11. A counter shaft 9 to which the rotation of the shaft 8 is transmitted, and a final gear that transmits power from the counter shaft 9 and performs forward rotation that is rotation when the vehicle 1 moves forward and reverse rotation that is rotation when the vehicle 1 moves backward. 14.

  Further, the final gear 14 is provided in the lower right part of FIG. 2 with respect to the input shaft 8 and scoops up the oil O stored at the bottom of the transaxle case 7. The reverse idler gear 13 rotates in the direction opposite to the rotation direction of the final gear 14, and the reverse idler gear 13 scoops up the oil O stored at the bottom of the transaxle case 7 upward.

  2, 4, and 5, a low speed side shift shaft 15, a high speed side shift shaft 16, and a fifth speed / reverse shift shaft 17 are parallel to the input shaft 8 around the transmission gear 11 of the input shaft 8. Is located.

  A low speed side shift yoke 18 is connected to the low speed side shift shaft 15, and a high speed side shift yoke 19 is connected to the high speed side shift shaft 16. The fifth speed / reverse shift shaft 17 is provided with a fifth speed / reverse shift yoke 20.

  The low speed side shift shaft 15 is provided with a low speed side shift fork 21 movably in the axial direction of the low speed side shift shaft 15. The low speed side shift fork 21 is composed of the first speed gear 11 </ b> A and the second speed gear. 12B and the first speed gear 12A and the second speed gear 12B of the transmission gear 12 are selectively meshed to switch between the first speed and the second speed.

  The high speed side shift shaft 16 is provided with a high speed side shift fork 22 that is movable in the axial direction of the high speed side shift shaft 16. The high speed side shift fork 22 includes the third speed gear 11 C and the fourth speed gear of the transmission gear 11. 11D and the 3rd speed gear 12C of the transmission gear 12 and the 4th speed gear 12D are selectively meshed to switch between the 3rd speed and the 4th speed.

  The 5-speed / reverse shift shaft 17 is provided with a 5-speed fork 23 and a reverse fork 24 movably in the axial direction of the 5-speed / reverse shift shaft 17. The 5-speed fork 23 engages and disconnects the 5-speed gear 11E of the transmission gear 11 and the 5-speed gear 12E of the transmission gear 12. The reverse fork 24 is connected to a reverse idler gear via a reverse lever 25. 13 and the reverse input gear 11F of the transmission gear 11 are engaged or disconnected.

  In FIG. 1, a shift device 26 is provided on the upper portion of the transaxle case 7, and this shift device 26 is linked to the operation of the shift lever operated by the driver, and the low speed side shift fork 21, the high speed side. The shift fork 22, the 5-speed fork 23 and the reverse fork 24 are operated.

  With this operation, the low-speed shift fork 21, the high-speed shift fork 22, the 5-speed fork 23, and the reverse fork 24 are moved in the axial direction of the low-speed shift shaft 15, the high-speed shift shaft 16, and the 5-speed / reverse shift shaft 17. By shifting and rotating around the axis, the shift speed is switched to an arbitrary shift speed.

  2, 3, and 6, a breather chamber 27 is formed in the upper transaxle case 7 with respect to the final gear 14 and the reverse idler gear 13, and the breather chamber 27 is formed inside the transaxle case 7. And partitioned. Here, the input shaft 8 is provided closest to the lower side of the breather chamber 27 with respect to the counter shaft 9, the reverse idler gear 13 and the final gear 14.

  The breather chamber 27 includes a clutch housing side breather chamber 28 and a transmission side breather chamber 29. The clutch housing side breather chamber 28 is formed on the upper facing surface 4 </ b> A of the clutch housing 4 facing the transmission case 6, and is composed of a space surrounded by the upper wall 30, the side wall 31, and the bottom wall 32.

  Further, the transmission-side breather chamber 29 is formed on the upper facing surface 6A of the transmission case 6 facing the clutch housing 4 and is composed of a space surrounded by the upper wall 33, the side wall 34, and the bottom wall 35.

  As shown in FIG. 6, the volume of the transmission-side breather chamber 29 is formed larger than the volume of the clutch housing-side breather chamber 28, and the transmission-side breather chamber 29 is located in the vehicle 1 with respect to the clutch housing-side breather chamber 28. It is formed long in the left-right direction.

  6 and 7, an air introduction hole 36 is formed in the bottom wall 32 of the clutch housing side breather chamber 28, and the air introduction hole 36 communicates with the inside of the transaxle case 7.

  In FIG. 6, an air discharge hole 37 is formed in the upper wall 33 of the transmission-side breather chamber 29, and the air discharge hole 37 communicates with the outside of the transaxle case 7. Therefore, the breather chamber 27 communicates the transaxle case 7 and the outside via the air introduction hole 36 and the air discharge hole 37. The air discharge hole 37 is closed by a pressure valve 44, and the pressure valve 44 is opened when the pressure inside the transaxle case 7 becomes a certain level or more.

  7 and 8, the air introduction hole 36 includes a front air introduction hole 36A and a rear air introduction hole 36B. The front air introduction hole 36A is arranged in front of the scattering direction of the oil scraped up by the final gear 14 during the forward rotation of the final gear 14 (in the direction indicated by the solid line in FIG. 2). The rear air introduction hole 36B is located behind the front air introduction hole 36A and behind the oil O in the scattering direction O1 and above the front air introduction hole 36A. .

  Further, a vertical rib 38 is formed in the bottom wall 32 of the clutch housing side breather chamber 28. As shown in FIG. 8, the vertical rib 38 is formed between the front air introduction hole 36A and the rear air introduction hole 36B. , Projecting downward from a virtual plane E1 connecting the front air introduction hole 36A and the rear air introduction hole 36B.

  In FIG. 6, the bottom wall 35 of the transmission-side breather chamber 29 has an inclined surface, which is inclined from the air discharge hole 37 toward the air introduction hole 36 in the height direction of the transaxle case 7. The slope is gradually lowered.

  7 and 8, when the clutch housing 4 is viewed from the axial direction of the input shaft 8, the bottom wall 32 of the clutch housing side breather chamber 28 is located in front of the front air introduction hole 36 </ b> A and introduces front air. The front bottom wall 32A that inclines toward the front upper side in the oil O scattering direction O1 from the hole 36A, and the rear bottom wall 32B that inclines toward the rear upper side in the oil O scattering direction O1 from the rear air introduction hole 36B. And an intermediate bottom wall 32C that is located between the front air introduction hole 36A and the rear air introduction hole 36B along the virtual plane E.

  Further, the vertical ribs 38 are formed on the intermediate bottom wall 32C so as to extend downward from the lower surface of the intermediate bottom wall 32C in the direction perpendicular to the virtual plane E1, and the vertical ribs 38 introduce the front air into the intermediate bottom wall 32C. It is formed at the end 32a on the hole 36A side.

  As shown in FIG. 8, first boss portions 39A and 39B for attaching a reverse lever 25 as a first transmission member are formed below the front bottom wall 32A on the lower end 32b side in the inclination direction. A second boss portion 40 for mounting the reverse fork 24 as a second speed change member is formed below the side bottom wall 32B on the side of the upper end 32c in the inclination direction.

  The vertical rib 38 is disposed between the first boss portions 39A and 39B and the second boss portion 40, and the lower end 38a of the vertical rib 38 is one of the first boss portions 39A and 39B. The boss portion 39 </ b> A is located on the boss virtual plane E <b> 2 connecting the central axis of the second boss portion 40.

  7 and 8, when the clutch housing 4 is viewed from the axial direction of the input shaft 8, the lower side of the front air introduction hole 36A is covered by the first boss portion 39A. On the other hand, when viewed from a direction orthogonal to the horizontal direction, the second boss portion 40 and the rear air introduction hole 36B are arranged so as to overlap in the horizontal direction.

  Further, a bearing portion 41 is formed on the wall surface 4B of the clutch housing 4, and this bearing portion 41 is interposed between the boss portion 41A, the inner peripheral portion of the boss portion 41A and the outer periphery of the input shaft 8. And a bearing (not shown) that is rotatably supported by the boss portion 41A of the input shaft 8.

  The lower end 32d in the inclination direction of the rear bottom wall 32B is installed immediately above the bearing portion 41, and the wall surface 4B of the clutch housing 4 is reinforced to extend from the lower end 32d in the inclination direction of the rear bottom wall 32B to the bearing portion 41. Ribs 42 are provided.

  An oil introduction portion 43 is formed in the boss portion 41A of the bearing portion 41 behind the reinforcing rib 42 in the oil O scattering direction O1, and the oil O colliding with the rear bottom wall 32B After being dropped through 42, the oil is supplied to the bearing through the oil introduction portion 43.

Next, the operation will be described.
In FIG. 9, when the input shaft 8 rotates in the counterclockwise direction indicated by the solid line when the vehicle 1 moves forward, the final gear 14 rotates in the counterclockwise direction via the counter shaft 9. At this time, the oil O stored at the bottom of the transmission case 6 is scraped up by the final gear 14. The oil O that has been scraped up by the final gear 14 travels downward along the longitudinal wall of the transmission case 6 in the front-rear direction of the vehicle 1 while being scattered in the direction of the breather chamber 27. The idler gear 13 and the bearings of the bearing portion 41 are lubricated.

  On the other hand, when the input shaft 8 rotates in the counterclockwise direction indicated by the solid line when the vehicle 1 moves backward, the power of the input shaft 8 rotates from the reverse idler gear 13 that rotates in the clockwise direction indicated by the broken line to the final gear via the counter shaft 9. 14 and the final gear 14 rotates in the clockwise direction indicated by the broken line.

  At this time, the oil O stored at the bottom of the transmission case 6 is scraped up by the final gear 14 and the reverse idler gear 13. As shown in FIG. 9, the oil O scraped up by the final gear 14 moves downward while being scattered in the direction of the breather chamber 27 along the front and rear upper walls of the clutch housing 4 and the transmission case 6 of the vehicle 1. By doing so, the transmission gears 11 and 12, the reverse idler gear 13, the bearings of the bearing portion 41, and the like are lubricated.

  Further, when the temperature and pressure inside the transaxle case 7 fluctuate and the air inside the transaxle case 7 expands, pressure is applied to the oil seal provided in the transaxle case 7 and the oil seal is deformed. There is a fear.

  In the transaxle case 7 of the present embodiment, a breather chamber 27 is formed in the upper transaxle case 7 with respect to the final gear 14 and the reverse idler gear 13, so that as shown in FIGS. The air ai of the axle case 7 is collected in the breather chamber 27 through the front air introduction hole 36A and the rear air introduction hole 36B, and is discharged to the outside through the air discharge hole 37. For this reason, the inside of the transaxle case 7 can be prevented from becoming a high pressure, and the oil seal provided in the transaxle case 7 can be prevented from being deformed by the pressure.

On the other hand, the oil O that has been scraped up by the final gear 14 may enter the breather chamber 27.
On the other hand, in the breather structure of the present embodiment, the volume of the transmission side breather chamber 29 is formed larger than the volume of the clutch housing side breather chamber 28, and the transaxle case is formed on the bottom wall 32 of the clutch housing side breather chamber 28. 7 is formed, and the air discharge hole 37 communicating with the outside is formed in the upper wall 33 of the transmission-side breather chamber 29. Therefore, the distance from the air introduction hole 36 to the air discharge hole 37 Can be lengthened.

  For this reason, when the oil O scraped up above the transaxle case 7 by the rotation of the final gear 14 or the reverse idler gear 13 enters the breather chamber 27 from the air introduction hole 36, the air discharge hole 36 37 can be made difficult to reach, and the oil O can be prevented from blowing out from the breather chamber 27 through the air discharge hole 37 to the outside.

  Further, according to the breather structure of the present embodiment, the bottom wall 35 of the transmission side breather chamber 29 is gradually lowered from the air discharge hole 37 toward the air introduction hole 36 in the height direction of the transaxle case 7. It is tilted.

  For this reason, as shown in FIG. 6, after the oil O that has been scraped up above the transaxle case 7 by the rotation of the final gear 14 or the reverse idler gear 13 enters the breather chamber 27 from the air introduction hole 36, the transmission side When flowing into the breather chamber 29, the inclined surface of the bottom wall 35 can make it difficult for the oil O to reach the air discharge holes 37. For this reason, it is possible to prevent oil from staying in the vicinity of the air discharge hole 37, and to more effectively prevent the oil O from being blown out from the breather chamber 27 through the air discharge hole 37.

  Further, according to the breather structure of the present embodiment, the air introduction hole 36 is formed in the front air introduction hole formed in front of the scattering direction O1 of the oil O scraped up by the final gear 14 during the forward rotation of the final gear 14. 36A and a rear air introduction hole 36B positioned behind the front air introduction hole 36A and behind the scattering direction O1 and above the front air introduction hole 36A.

  In addition, a front air introduction hole 36A and a rear air introduction hole 36B are provided in the bottom wall 32 of the clutch housing side breather chamber 28 so that the front air introduction hole 36A is positioned below the rear air introduction hole 36B. As shown in FIG. 10, when the oil O scraped up by the final gear 14 that rotates forward in the counterclockwise direction when the vehicle moves forward enters the rear air introduction hole 36B, as shown in FIG. After flowing into the front air introduction hole 36A formed at a position lower than the side air introduction hole 36B, it can be returned to the transmission case 6.

  A virtual plane E1 connecting the front air introduction hole 36A and the rear air introduction hole 36B to the bottom wall 32 of the breather chamber 28 on the clutch housing side between the front air introduction hole 36A and the rear air introduction hole 36B. Since the vertical rib 38 projecting downward from the vehicle is formed, the oil O that is scraped up by the final gear 14 that rotates forward when the vehicle moves forward and flows from the lower side of the rear air introduction hole 36B to the front air introduction hole 36A. It is possible to prevent the oil O from entering the front air introduction hole 36A by colliding with the vertical ribs 38 and to make it difficult to enter the breather chamber 27 from the front air introduction hole 36A.

  Further, when the vehicle reverses, oil that is scraped up by the reverse rotation of the final gear 14 or the rotation of the reverse idler gear 13 that rotates in the clockwise direction and flows from below the front air introduction hole 36A to the rear air introduction hole 36B. The oil O can be prevented from entering the rear air introduction hole 36B by colliding with the vertical ribs 38, so that it is difficult to enter the breather chamber 27 from the rear air introduction hole 36B.

  As a result, the amount of oil O entering the breather chamber 27 can be reduced, and the oil O can be more effectively prevented from blowing out from the breather chamber 27 through the air discharge hole 37.

  Further, according to the breather structure of the present embodiment, when the clutch housing 4 is viewed from the axial direction of the input shaft 8, the bottom wall 32 of the clutch housing side breather chamber 28 is positioned forward of the front air introduction hole 36A. Since the front bottom wall 32A is inclined from the front air introduction hole 36A toward the front upper side in the scattering direction, the oil O scraped up by the reverse rotation of the final gear 14 or the rotation of the reverse idler gear 13 when the vehicle moves backward is used. It can guide below 36 A of front air introduction holes along the inclined surface of 32 A of front side bottom walls. For this reason, it is possible to make it difficult for the oil O to enter the front air introduction hole 36A (see FIG. 10).

  Further, when the clutch housing 4 is viewed from the axial direction of the input shaft 8, the rear side in which the bottom wall 32 of the breather chamber 28 on the clutch housing side is inclined rearward and upward in the scattering direction O1 from the rear air introduction hole 36B. Since the bottom wall 32B is provided, the oil O scraped up by the forward rotation of the final gear 14 when the vehicle moves forward can be guided below the rear air introduction hole 36B along the inclined surface of the rear bottom wall 32B. . For this reason, it is possible to make it difficult for the oil O to enter the rear air introduction hole 36B (see FIG. 10).

  Further, according to the breather structure of the present embodiment, when the clutch housing 4 is viewed from the axial direction of the final gear 14, the bottom wall 32 of the clutch housing side breather chamber 28 is connected to the front air introduction hole 36A and the rear air introduction. The intermediate bottom wall 32C is located between the hole 36B and extends along the virtual plane E1, and the vertical rib 38 extends vertically downward from the lower surface of the intermediate bottom wall 32C in the direction perpendicular to the virtual plane E1. It is formed on the wall 32C.

  Therefore, when the vehicle moves forward, the oil O, which is scraped up by the forward rotation of the final gear 14 and flows from the rear air introduction hole 36B toward the front air introduction hole 36A below the breather chamber 27, passes through the intermediate bottom wall 32C and the vertical wall. It can be blocked by the ribs 38 and can be prevented from flowing from the rear air introduction hole 36B toward the front air introduction hole 36A below the breather chamber 27. For this reason, it is possible to prevent the oil O from entering the breather chamber 27 from the front air introduction hole 36A (see FIG. 10).

  On the other hand, when the oil O enters the breather chamber 27 from the rear air introduction hole 36B, the oil O tends to flow to the front air introduction hole 36A formed at a position lower than the rear air introduction hole 36B. When a large amount of oil O enters the air introduction hole 36 </ b> A, the oil O tends to stay in the breather chamber 27.

  On the other hand, in the breather structure of the present embodiment, since the vertical rib 38 is formed at the end 32a on the front air introduction hole 36A side of the intermediate bottom wall 32C, the space below the front air introduction hole 36A is formed in the vertical rib. 38 can be reduced by securing the installation space 38, and a large amount of oil O can be prevented from entering the front air introduction hole 36A (see FIG. 10).

  Further, according to the breather structure of the present embodiment, since the first boss portions 39A and 39b for mounting the reverse lever 25 are formed below the lower end 32b side in the inclination direction of the front bottom wall 32A, the front bottom wall 32A The first boss portions 39A and 39B can reduce the space below the front bottom wall 32A. For this reason, the oil O which penetrates into the front air introduction hole 36A through the gap between the front bottom wall 32A and the first boss portions 39A and 39B can be reduced (see FIG. 10).

  Further, since the second boss portion 40 for attaching the reverse fork 24 is formed below the rear bottom wall 32B on the inclined direction upper end 32c side, the rear bottom wall 32B and the second boss portion 40 can The space below the side air introduction hole 36B can be reduced. For this reason, the oil O which penetrates into the rear air introduction hole 36B through the gap between the rear bottom wall 32B and the second boss portion 40 can be reduced (see FIG. 10).

  Further, the vertical rib 38 is disposed between the first boss portion 39A and the second boss portion 40, and the lower end 38a of the vertical rib 38 is connected to the central axis of the first boss portion 39A and the second boss portion 40. The oil O that has flowed into the front air introduction hole 36A through the gap between the front bottom wall 32A and the first boss portion 39A and the rear bottom The oil O that has flowed into the rear air introduction hole 36 </ b> B through the gap between the wall 32 </ b> B and the second boss portion 40 can collide with the vertical ribs 38. It can be guided downward (see FIG. 10).

  As a result, it is possible to make it difficult for the oil O to enter the breather chamber 27, and to more effectively prevent the oil O from being blown out from the breather chamber 27 through the air discharge hole 37.

  Further, according to the breather structure of the present embodiment, when the clutch housing 4 is viewed from the axial direction of the input shaft 8, the lower side of the front air introduction hole 36A is covered by the first boss portion 39A. It is possible to prevent the oil O scraped up by the rotation of the reverse idler gear 13 or the final gear 14 rotating in the reverse direction from colliding with the first boss portion 39A and directly entering the front air introduction hole 36A ( (See FIG. 10).

  Further, since the second boss portion 40 and the rear air introduction hole 36B are disposed so as to overlap in the horizontal direction when viewed from the direction orthogonal to the axial direction of the input shaft 8, the vehicle moves forward. It is possible to prevent the oil O scooped up by the final gear 14 rotating forward at times from colliding with the second boss portion 40 and directly entering the rear air introduction hole 36B (see FIG. 10).

  Further, according to the breather structure of the present embodiment, the lower end in the inclination direction of the rear air introduction hole 36 </ b> B is installed directly above the bearing portion 41 that rotatably supports the axial end portion of the input shaft 8 on the clutch housing 4. The wall 4B of the clutch housing 4 is provided with a reinforcing rib 42 extending from the lower end 32d in the inclined direction of the rear bottom wall 32B to the bearing 41, and the boss 41A of the bearing 41 at the rear of the reinforcing rib 42 in the scattering direction. In addition, an oil introduction portion 43 was formed.

  For this reason, the oil O that flows along the rear bottom wall 32B after being scraped up by the final gear 14 that rotates forward when the vehicle moves forward is transmitted along the reinforcing rib 42 from the lower end 32b in the inclined direction of the rear bottom wall 32B. 6 can be guided below. For this reason, the oil O can be kept away from the rear air introduction hole 36B and hardly enter the rear air introduction hole 36B, and the oil O can be prevented from entering the breather chamber 27 more effectively (see FIG. 10).

  Further, the oil O guided below the transmission case 6 along the reinforcing rib 42 can be supplied to the bearing of the bearing portion 41 through the oil introduction portion 43, and the lubricating performance of the bearing portion 41 can be improved. (See FIG. 10). In addition, the rigidity of the clutch housing 4 can be increased by the reinforcing rib 42.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Engine (internal combustion engine), 3 ... Power transmission device, 4 ... Clutch housing, 4A ... Upper facing surface (upper facing surface of clutch housing), 4A ... Wall surface (wall surface of clutch housing), 6 ... Transmission Case: 6A ... Upper facing surface (upper facing surface of transmission case), 7 ... Transaxle case (main body case), 8 ... Input shaft, 9 ... Counter shaft, 11 ... Transmission gear (input transmission gear), 13 ... Reverse idler gear, 14 ... final gear, 24 ... reverse fork (first transmission member), 25 ... reverse lever (second transmission member), 27 ... breather chamber, 28 ... clutch housing side breather chamber, 29 ... transmission side Breather chamber, 30 ... upper wall (upper wall of the breather chamber on the clutch housing side), 31 ... side wall (clutch housing) 32B ... the bottom wall (the bottom wall of the clutch housing side breather chamber), 32A ... the front bottom wall, 32B ... the rear bottom wall, 32C ... the intermediate bottom wall, 32a ... the end (intermediate bottom wall) 32b... Lower end in the tilt direction (lower end in the tilt direction of the front bottom wall), 32c. Upper end in the tilt direction (upper end in the tilt direction of the rear bottom wall), 32d ... lower end in the tilt direction (rear side) Lower end in the inclination direction of the bottom wall), 33 ... Upper wall (upper wall of the transmission case side breather chamber), 34 ... Side wall (side wall of the transmission case side breather chamber), 35 ... Bottom wall (bottom wall of the transmission case side breather chamber) 36 ... Air introduction hole, 36A ... Front air introduction hole, 36B ... Rear air introduction hole, 37 ... Air discharge hole, 38 ... Vertical rib, 38a ... Lower end (lower end of vertical rib), 41 ... Bearing portion, 42 ... Reinforcing ribs, E1 ... Virtual plane, E2 ... boss between virtual planes, O ... oil, O1 ... scattering direction of the oil

Claims (9)

An input shaft that is rotated by the power of the internal combustion engine, a transmission gear provided on the input shaft or a counter shaft to which rotation of the input shaft is transmitted via a reverse idler gear that is separate from the transmission gear, and the counter shaft Power is transmitted, and there is a final gear that performs forward rotation that is rotation at the time of forward movement of the vehicle and reverse rotation that is rotation at the time of backward movement of the vehicle, and the oil stored at the bottom is transferred to the final gear or the reverse idler A transmission case configured to be scraped by a gear;
A main body case configured to include a clutch housing in which the clutch mechanism is housed,
A breather structure of a power transmission device in which a breather chamber partitioned from the inside of the main body case is formed in the main body case above the final gear and the reverse idler gear;
The breather chamber is formed on an upper facing surface of the clutch housing facing the transmission case, and is surrounded by an upper wall, a side wall and a bottom wall, and a breather chamber on the clutch housing side, and an upper portion of the transmission case facing the clutch housing. A transmission-side breather chamber formed on the opposing surface and surrounded by an upper wall, a side wall, and a bottom wall;
A volume of the transmission-side breather chamber is formed larger than a volume of the clutch housing-side breather chamber;
An air introduction hole communicating with the inside of the main body case is formed in the bottom wall of the breather chamber on the clutch housing side,
A breather structure for a power transmission device, wherein an air discharge hole communicating with the outside is formed in the upper wall of the transmission-side breather chamber.   The bottom wall of the transmission-side breather chamber is inclined so as to gradually become lower from the air discharge hole toward the air introduction hole in the height direction of the main body case. Breather structure of the power transmission device. The air introduction hole includes a front air introduction hole formed in front of the oil scattering direction scraped up by the final gear during the forward rotation of the final gear, and a rear side in the scattering direction with respect to the front air introduction hole. And a rear air introduction hole located above the front air introduction hole,
Downward from a virtual plane connecting the front air introduction hole and the rear air introduction hole to the bottom wall of the breather chamber on the clutch housing side between the front air introduction hole and the rear air introduction hole. The breather structure of the power transmission device according to claim 1, wherein a protruding vertical rib is formed. The input shaft, the rotation shaft of the reverse idler gear, and the rotation shaft of the final gear are arranged in parallel, and the input shaft is below the breather chamber with respect to the reverse idler gear, the counter shaft, and the final gear. Provided closest to the
When the clutch housing is viewed from the axial direction of the input shaft, the bottom wall of the breather chamber on the clutch housing side is located in front of the front air introduction hole and extends in the scattering direction from the front air introduction hole. 4. The front bottom wall inclined toward the front upper side and the rear bottom wall inclined toward the rear upper side in the scattering direction from the rear air introduction hole are formed. The breather structure of the power transmission device described in 1. When the clutch housing is viewed from the axial direction of the input shaft, the bottom wall of the breather chamber on the clutch housing side is located between the front air introduction hole and the rear air introduction hole, and the virtual plane An intermediate bottom wall along the
5. The power transmission according to claim 3, wherein the vertical rib is formed on the intermediate bottom wall so as to extend downward from a lower surface of the intermediate bottom wall in a direction perpendicular to the virtual plane. The breather structure of the device.   The breather structure for a power transmission device according to claim 5, wherein the vertical rib is formed at an end of the intermediate bottom wall on the front air introduction hole side. A first boss part for mounting the first speed change member is formed below the lower end side in the inclination direction of the front bottom wall,
A second boss part for mounting the second speed change member is formed below the upper end side in the inclination direction of the rear bottom wall,
The vertical rib is disposed between the first boss portion and the second boss portion,
7. The power according to claim 6, wherein a lower end of the vertical rib is located on a virtual plane between the bosses connecting the central axis of the first boss part and the central axis of the second boss part. Breather structure of transmission device. When the clutch housing is viewed from the axial direction of the input shaft, the lower side of the front air introduction hole is covered by the first boss portion,
The second boss portion and the rear air introduction hole are arranged so as to overlap in the horizontal direction when viewed from a direction orthogonal to the axial direction of the input shaft. Item 9. A breather structure for a power transmission device according to Item 7. The lower end in the inclination direction of the rear bottom wall is installed directly above the bearing portion that rotatably supports the axial end of the input shaft on the clutch housing,
On the wall surface of the clutch housing, a reinforcing rib extending from the lower end in the inclination direction of the rear bottom wall to the bearing portion is provided,
The breather structure of the power transmission device according to claim 4, wherein an oil introduction portion is formed in the bearing portion behind the reinforcing rib in the scattering direction.

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