JPH0570019B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a structure for supporting a countershaft of an automatic transaxle on a transmission case.

(Prior Technology) Automatic transaxles consist of an automatic transmission and a differential gear in one unit, and are suitable for front engine/front wheel drive vehicles (FF vehicles) and rear engine/rear wheel drive vehicles (RR vehicles). ) used for

Incidentally, such a transmission system is often used in small cars, and is usually installed horizontally (extending in the width direction of the vehicle) together with the engine. Therefore, if the power shifted on the main axis is directly input to the differential gear, the differential gear will be located far away from the center between the left and right drive wheels, and the left and right drive wheels will The axle length of the wheels leads to very different inconveniences. For this reason, normally, the power that has been shifted on the main axis is returned by a countershaft parallel to the main axis, and is then transmitted sequentially through a final drive pinion provided at the corresponding end of the countershaft and a final drive ring gear that meshes with this pinion. The signal is transmitted to the differential gear.

The countershaft is supported on the transmission case at the input end of the shifting power and at a location near the final drive pinion. Since it is large, it requires a large capacity.

For this reason, as seen in the A130 type transaxle manufactured by Toyota Motor Corporation, the transmission case portion into which the outer race of the bearing is fitted extends over the entire circumference of the outer race. It was customary to fit the outer race around the entire circumference to the corresponding part of the transmission case.

By the way, when designing a transaxle, the position of the axis of the final drive ring gear is determined by the position of the wheel, and the position of the main axis, which is coaxial with the engine crankshaft, is determined by the position of the final drive ring gear and the engine room. In order to reduce the size of the transaxle, it is effective to reduce the distance between the main axis and the countershaft axis.

However, in this countershaft support structure, there is an outer race fitting wall of the transmission case near the plane that includes the main axis and the countershaft axis, and the distance between the main axis and the countershaft axis is increased to increase the size of the transaxle. It is inevitable that the diameter and weight will increase.

Therefore, a countershaft support structure as shown in Fig. 5 has been proposed, which is used in the ZF4HP14 type transaxle manufactured by West Germany's Tournrad Verbrig Friedrichs Halfen Aktiengesellschaft. This support structure moves the bearing a close to the main axis d so that the transmission case portion c into which the outer race b of the bearing a is fitted does not exist near the plane that includes the main axis d and the axis of the countershaft e. It is something. The reduction in support rigidity of the bearing a and therefore the countershaft e due to the above is compensated for by the fastening force of the bolt f screwed into the outer periphery of the outer race b from the opposite direction.

(Problems to be Solved by the Invention) However, this countershaft support structure causes the following problems. That is, at the location where bolt f is screwed in, a plurality of reinforcing ribs are unavoidable to prevent the transmission case part that houses the differential gear from falling down, but because of the presence of bolt f, these reinforcing ribs can be placed in efficient positions ( The reinforcing ribs cannot be provided at the connection point between the main body of the transmission case and the differential gear housing, and the number of reinforcing ribs increases, which hinders weight reduction. Further, the control valve for speed change control, which is most preferably mounted on the lower surface of the transmission case, has to be installed at a different location due to the presence of the bolt f, making it difficult to route the oil passages.

Furthermore, when trying to place a pair of bearings in the differential gear case on both sides of the final drive ring gear, one of the bearings must be placed on one side of the final drive ring gear in order to allow bolt f to be screwed down. It must be placed to support the differential gear case. However, in this case, the final drive ring gear is supported in a cantilevered manner and is inevitably tilted, causing problems such as increasing gear noise and shortening the life of the gear.

In addition, in order to allow the bolt f to be screwed in, the outer race b needs to be loose with respect to the fitting part c so that it can be aligned. It is inevitable that the gear e will be misaligned, and this will also cause gear noise and shorten the life of the gear.

Furthermore, the outer race b needs to be made thicker in consideration of the screwing amount of the bolt f, and the influence on the surrounding area cannot be ignored, such as sacrificing the area of the oil pump suction port, for example.

(Means for Solving the Problems) In view of these problems, the present invention provides a system in which the power shifted on the main axis is returned by a countershaft parallel to the main axis, and then provided at the corresponding end of the countershaft. The automatic transmission is configured such that the power is transmitted to a differential gear through a final drive pinion and a final drive ring gear that meshes with the pinion, and the countershaft is supported on a transmission case via a bearing near the final drive pinion. In the tick transaxle, the bearing is moved close to the main axis so that the hole wall of the transmission case into which the outer race of the bearing fits does not exist near the plane including the main axis and the countershaft axis, and the outer race is fitted into the outer race. The bearing is characterized in that the bearing is provided with a projecting ear projecting outward in the radial direction, and the bearing is attached to the transmission case with a bolt that is inserted through the projecting ear and extends in the axial direction of the countershaft. .

(Operation) The power shifted on the main axis passes through the countershaft, final drive pinion, and final drive ring gear in sequence, reaches the differential gear, and is distributed and output from the differential gear.

By the way, the bearing is installed so that the hole wall of the transmission case for fitting the outer race of the bearing supporting the countershaft near the final drive pinion does not exist near the surface including the main axis and the countershaft axis. Since the transaxle is placed close to the main axis, there is no part of the transmission case for fitting the outer race near the surface, so the distance between the main axis and the countershaft can be reduced, making it possible to reduce the diameter and weight of the transaxle.

Because of this configuration, the outer race is not fitted around the entire circumference, so in order to compensate for the lack of bearing strength, the outer race itself is provided with projecting ears that protrude outward in the radial direction, and the counter Since the above-mentioned bearing is attached to the transmission case with a bolt extending in the axial direction of the shaft,
The above-mentioned bolts are located in positions that are unrelated to the reinforcing ribs that prevent the transmission case that houses the differential gear from collapsing, and to the control valves that are conveniently placed for oil passage management. In addition, the thickness of the outer race only needs to be strong enough to support the countershaft, and the outer race can be fitted into another support member, and this support member can be provided with radial protrusions and attached to the transmission case with bolts. In comparison, the support member must be strong enough to support the countershaft and thick enough to withstand fitting of the outer race, so the bearing support structure cannot be enlarged in the radial direction due to this large thickness. Therefore, the other effects described below can be achieved without causing a situation where the above effects of shortening the distance between the main axis and the countershaft are canceled out. . In other words, it is possible to reduce the number of reinforcing ribs by providing them at efficient positions, and it is also possible to avoid inconvenient changes in the position of the control valve.

Furthermore, the position of the bolts described above does not prevent the pair of bearings for the differential gear case from being placed on both sides of the final drive ring gear, and makes it possible to support the final drive ring gear on both sides, thereby reducing gear noise. This is a significant advantage in terms of longevity.

Furthermore, since the bolts reinforce and support the outer race against the transmission case by tightening force in the axial direction, even when the outer race is loosely fitted into the transmission case for positioning, the countershaft No misalignment occurs. In addition, for the same reason, the screwing amount of the bolt does not affect the wall thickness of the outer race, and there is no need to increase this wall thickness. You can eliminate all of them.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

1 and 2 show an embodiment of the present invention, in which 1 is a transmission case, 2 is a main axis, 3 is a countershaft, 4 is a final drive pinion, 5 is a final drive ring gear, and 6 is a transmission case. The differential gears are shown respectively.

An input shaft 7 and an output shaft 8 are provided coaxially and relatively rotatably on the main axis 2, and a normal planetary gear type gear transmission mechanism 9 is provided on these shafts. Engine power is supplied to the input shaft 7 via a torque converter 10, and the gear transmission mechanism shifts the engine power at gears determined by selective hydraulic operation of various friction elements (clutches, brakes, etc.) including a handbrake 11. and is transmitted to the output shaft 8. The output shaft 8 has an output gear 1
Counter gear 1 integrally molded with 2 and meshing with the counter gear 1
3 to the countershaft 3.

The countershaft 3 has one end connected to the counter gear 13
and supported on the transmission case 1 by bearings 14,
The transmission case 1 is connected to the transmission case 1 by a bearing 15 near the final drive pinion 4 integrally molded on the other end.
The main axis 2 is supported parallel to the main axis 2. By the way, in the present invention, the hole wall of the transmission case into which the outer race 15a of the bearing 15 is fitted is aligned with the plane x that includes the main axis 2 and the axis of the countershaft 3.
(See FIG. 2) The bearing 15 is brought close to the main axis 2 so that it disappears in the vicinity as shown by 1a.

And the bearing 15 is insufficient due to the notch 1a.
In order to supplement the support strength of the outer race 5a, as shown in FIGS. 3 and 4, a plurality of (four in the illustrated example) protruding ears extending radially outward are arranged at equal intervals in the circumferential direction. 16 are provided, and bolt insertion holes 1 are provided in these.
Drill 6a. A bolt 17 is inserted into each hole 16a to extend in the axial direction of the countershaft 3,
By screwing these bolts 17 into corresponding female threads of the transmission case 1, the outer race 15a, and thus the bearing 15, are attached to the transmission case 1.

The final drive ring gear 5 meshes with the final drive pinion 4 and is connected to the case 6a of the differential gear 6, and the differential gear 6a is connected to a pair of bearings 18 and 19 disposed on both sides of the final drive ring gear 5. It is supported on the transmission case 1 by.

The operation of the above embodiment will be explained next.

The engine power that has passed through the torque converter 10 and reached the input shaft 7 is changed in speed by the gear transmission mechanism 9 according to the selected gear position, and is output to the output shaft 9. This shifting power is input to the differential gear 6 through the output gear 12, counter gear 13, counter shaft 3, final drive pinion 4, and final drive ring gear 5, and is distributed and output from the differential gear 6.

By the way, the bearing 1 that supports the countershaft 3 near the final drive pinion 4
Since the bearing 15 is brought close to the main axis 2 so that the hole wall of the transmission case for fitting the outer race 15a of No. 5 does not exist in the vicinity 1a of the plane x including the main axis 2 and the countershaft axis, Since there is no transmission case portion for fitting the outer race in the vicinity, the distance between the main axis 2 and the countershaft 3 axis can be reduced accordingly, and the transaxle can be made smaller in diameter and lighter in weight.

Because of this configuration, the outer race 15a is not fitted around the entire circumference, so in order to compensate for the lack of bearing support strength, the outer race 15a is provided with protruding ears 16 that protrude outward in the radial direction. Bolt 1 extending in the axial direction
Since the bearing 15 is attached to the transmission case 1 at step 7, the bolt 17 is placed conveniently for the reinforcement ribs that prevent the transmission case portion housing the differential gear 6 from falling down and for the management of the oil passage. The control valve is located in a position unrelated to the control valve. Therefore, the number of reinforcing ribs can be reduced by providing them at efficient positions, and inconvenient positional changes of the control valve can be avoided.

Further, the position of the bolt 17 does not prevent the pair of bearings 18 and 19 for the differential gear case 6a from being disposed on both sides of the final drive ring gear 5, and the final drive ring gear 5 is supported on both sides thereof. As shown in FIG. 1, this is advantageous in terms of gear noise and gear life.

Furthermore, since the bolts 17 reinforce and support the outer race 15a to the transmission case 1 by tightening force in the axial direction, the countershaft will not fit even when the outer race 15a is loosely fitted into the transmission case for positioning. No misalignment of 3 will occur. In addition, for the same reason, the screwing amount of the bolt 17 does not affect the wall thickness of the counter race 15.
There is no need to increase this wall thickness, so that there is no impact on the surrounding area, such as sacrificing the area of the oil pump suction hole 20 (see FIG. 2).

(Effects of the Invention) Thus, as described above, the countershaft support structure of the present invention reduces the bearing support that occurs when the outer race 15a is not fitted all the way around when the bearing 15 is moved closer to the main axis 2 in order to reduce the diameter of the transaxle. In order to compensate for the lack of strength, outer lace 15a
Since the bearing 15 is reinforced and supported on the transmission case 1 by the bolt 17 inserted in the protrusion 16 and extending in the axial direction, the differential gear 6 of the transmission case can be attached as described above. There is no restriction on the arrangement of the reinforcing ribs and control valves that prevent the storage part from collapsing, and these can be installed at optimal positions. This can be advantageous in terms of gear noise and gear life. Also, outer lace 15a
Even if the countershaft 3 is fitted loosely into the transmission case so that the outer race 1 can be aligned, the countershaft 3 will not be misaligned, and the
There is no reason for the wall thickness of 5a to become thicker, and there is no adverse effect on the surrounding area at all. Furthermore, since the outer race 15a is directly attached to the transmission case 1 by providing a protrusion 16 on the outer race 15a itself and using a bolt 17 inserted through the protrusion 16 and extending in the axial direction, it is possible to fit the outer race to another support member. By bolting this supporting member to the transmission case through the radial protruding ears provided thereon, the large wall thickness of the supporting member allows the bearing to be The above-mentioned various methods can be implemented without the support structure being enlarged in the radial direction, and without canceling out the original effect of shortening the distance between the main axis and the countershaft. It can have effects.

[Brief explanation of drawings]

Fig. 1 is an exploded sectional view of essential parts of an automatic transaxle showing an embodiment of the present invention, Fig. 2 is a front view of the essential parts thereof, Fig. 3 is a front view of a bearing used in the present invention, and Fig. 4. is a cross-sectional view of Fig. 3,
FIG. 5 is an explanatory diagram showing a conventional countershaft support structure. 1... Transmission case, 2... Main axis, 3... Counter shaft, 4... Final drive pinion, 5... Final drive ring gear, 6
... Differential gear, 7 ... Input shaft, 8
... Output shaft, 9 ... Gear transmission mechanism, 10 ... Torque converter, 12 ... Output gear, 13 ... Counter gear, 15 ... Bearing, 15a ... Outer race, 16 ... Projection, 17 ... Bolt .

Claims (1)

[Claims] 1. The power shifted on the main axis is returned by a countershaft parallel to the main axis, and then a final drive pinion provided at the corresponding end of the countershaft and a final drive ring gear meshed with this pinion are used. in an automatic transaxle in which the power is sequentially transmitted to a differential gear, and the countershaft is supported on a transmission case via a bearing near the final drive pinion, the outer race of the bearing is fitted. The bearing is moved close to the main axis so that the hole wall of the transmission case does not exist in the vicinity of the plane including the main axis and the countershaft axis, and the outer race itself is provided with protruding ears that protrude outward in the radial direction. . A countershaft support structure for an automatic transaxle, characterized in that the bearing is attached to a transmission case with a bolt that is inserted through the protrusion and extends in the axial direction of the countershaft.