JPH1151159A - Bearing device of pinion shaft for final reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress excessive supply of a lubricating oil to a conical roller bearing which rotatably supports a pinion shaft by narrowing a clearance which becomes a supply passage which conducts lubricating oil to a small diameter side of a conical roller by a swelled part provided in an outer peripheral part of an inner ring spacer. SOLUTION: For example, in a final reduction gear 30, clearances 33, 34 which become supply passages which conduct lubricating oil 20 to a small diameter side of a conical roller of each conical roller bearing 12, 13 from a lubricating oil guide wall face 22 are narrowed by a swelled part 36 provided on a spacer 31 arranged between inner rings 12b and 13b of the conical bearings 12, 13. For this reason, even if an amount of lubricating oil to be supplied to the lubricating oil guide wall face 22 increases due to springing up of a ring gear 5 in accordance with an increase of a rotation speed of a pinion shaft 10 and the pump operation in each conical roller bearing 12, 13 itself increases, the supply of the amount of lubricating oil for respective conical roller bearings 12, 13 is suppressed. Consequently, it is possible to suppress the excessive supply of lubricating oil 20 caused by an increase of a rotation speed of the pinion shaft 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a pinion shaft for a final reduction gear, and more particularly to an improvement for preventing a reduction in bearing life of a tapered roller bearing that supports a shaft portion of a pinion shaft.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventional example of a final reduction gear for a vehicle. These vehicle final reduction gears 1 and 2 each include a housing 4 having an oil-tight structure,
A ring gear 5 rotatably supported in the housing 4 and transmitting a rotational force to left and right drive shafts via differential gear means (not shown); and a shaft portion 7 having the housing 4 inserted therein, the ring gear 5 being located in the housing 4. A pinion gear 8 meshing with the ring gear 5 is provided at a leading end, and a pinion shaft 10 to which a propeller shaft (not shown) is connected via a companion flange 9 is provided at a base end located outside the housing 4. Configuration.

[0003] These final reduction gears for vehicles 1 and 2 have outer rings 12a and 13a so that the small diameter sides of the tapered rollers face each other.
Are fitted to bearing supports 4a, 4b in the housing 4, and inner rings 12b, 13b are fitted to the shaft 7 of the pinion shaft 10 to be assembled on the back to rotatably support the pinion shaft 10. A pair of tapered roller bearings 12,
13, between the pair of tapered roller bearings 12, 13 is fitted to the shaft portion 7 of the pinion shaft 10, and both ends of the inner ring 1 abut on the inner rings 12b, 13b.
A bearing device comprising a substantially cylindrical spacer 15 which is an inner ring spacer for keeping the interval between 2b and 13b constant.

The inner race 12b of the tapered roller bearing 12 inserted into the shaft 7 of the pinion shaft 10, the spacer 15,
The inner ring 13b of the tapered roller bearing 13 is sandwiched between the companion flange 9 and the pinion gear 8 by tightening the companion flange 9 fitted to the base end of the shaft portion 7 with a tightening nut 16, Axial movement is regulated and preload is applied. An oil seal 14 that seals a gap between the companion flange 9 and the housing 4 is provided on a cylindrical portion of the companion flange 9 fitted to the shaft portion 7 of the pinion shaft 10.

In the case of the final reduction gear 1 for a vehicle shown in FIG. 9, the bearing supports 4a and 4b are integrally formed with the housing 4 accommodating the ring gear 5. However, FIG.
In the case of the final reduction gear 2 for a vehicle shown in FIG. 1, the bearing supports 4a and 4b are integrally formed with a retainer 6 which is screwed to a housing body housing the ring gear 5.

Therefore, in the case of the vehicle final reduction gear 2 shown in FIG. 10, the pinion shaft 1 is attached to the retainer 6 with the retainer 6 removed from the housing body.
0, the tapered roller bearings 12, 13 and the spacer 15 are assembled, and then the retainer 6 is fastened and fixed to the housing body. Therefore,
Since the vehicle final reduction gear 2 has a structure in which the bearing support portions 4a and 4b are provided on the retainer 6 separate from the housing body, the support of the pinion shaft 10 is also improved. That is, the pinion shaft 10 is also provided with a short shaft portion 17 coaxially with the shaft portion 7 on the distal end side of the pinion gear 8, and the shaft portion 17 is formed as a third member integrally formed with the housing body.
Is rotatably supported through the roller bearing 18 via the roller bearing 18 so that the support of the pinion shaft 10 is strengthened.

On the other hand, the final reduction devices 1 and 2 for a vehicle as described above.
In order to maintain the performance of the pair of tapered roller bearings 12, 13 supporting the shaft portion 7 of the pinion shaft 10 satisfactorily over a long period of time, it is necessary to supply lubricating oil. Therefore, in the vehicle final reduction gears 1 and 2, the lubricating oil 20 stored in the lower portion of the ring gear 5 at the bottom of the housing 4
The lubricating oil guide wall surface 22 is secured on the upper inner wall of the housing 4 while being immersed inside.

The lubricating oil guide wall surface 22 transmits the lubricating oil 20 which has been splashed up to the upper inner wall of the housing 4 by the ring gear 5 rotating during traveling of the vehicle, as shown by the arrow in the drawing. A pair of tapered roller bearings 1
An appropriate slope is provided so as to guide between 2 and 13. When the tapered roller bearing is rotationally driven, a pump action for supplying liquid from the small diameter side to the large diameter side occurs due to a difference in peripheral speed between the large diameter side and the small diameter side of the tapered roller.

Therefore, the lubricating oil 20 guided by the lubricating oil guide wall surface 22 to the portion between the tapered roller bearings 12 and 13
Flows through the tapered roller bearings 12, 13 from the smaller diameter side to the larger diameter side of the tapered roller bearings 12 and 13 by a pump action generated in the tapered roller bearings 12, 13, and the tapered roller bearings 12, 13
Perform lubrication inside.

[0010]

By the way, in the above-described vehicle final reduction gears 1 and 2, when the vehicle travels at a high speed, the pinion shaft 10 connected to the propeller shaft is not used.
Rotates at a high speed, and naturally, the rotation of the ring gear 5 driven by the pinion shaft 10 is also accelerated. Therefore, the amount of lubricating oil which is jumped up by the ring gear 5 and supplied to the portion between the tapered roller bearings 12 and 13 via the lubricating oil guide wall surface 22 increases.

When the rotation of the pinion shaft 10 is accelerated, the rotation of each of the tapered roller bearings 12, 13 inserted into the shaft portion 7 of the pinion shaft 10 is also accelerated, and these cones are rotated. The pumping action of the roller bearings 12, 13 is also enhanced. That is, as the rotation speed of the shaft portion 7 increases, the amount of lubricating oil supplied from the lubricating oil guide wall surface 22 increases, and at the same time, the pumping action of the tapered roller bearings 12 and 13 increases. As a result, the amount of lubricating oil flowing through the tapered roller bearings 12 and 13 gradually increases as the rotation speed increases.

On the other hand, the amount of lubricating oil necessary for stable operation of the tapered roller bearings 12, 13 is determined by
Does not increase much. Therefore, the tapered roller bearings 12, 13
In the conventional structure in which the amount of lubricating oil flowing through the motor gradually increases as the rotation speed increases, a situation arises in which more lubricating oil is gradually supplied from the viewpoint of lubrication performance. However,
The inflow of lubricating oil into the respective tapered roller bearings 12, 13 is due to the pumping action of the respective tapered roller bearings 12, 13 itself. In itself, it does not matter.

However, in the lubricating oil 20, abrasion powder or abrasives (parts which could not be completely removed after finishing the surface of each part) constituting the differential gear means in the housing 4 are contained. Foreign matter has entered. For this reason, the circulation of the lubricating oil 20 more than necessary depends on the foreign matter and the tapered roller bearing 1.
This increases the chances of contact with the tapered roller bearings 12 and 13 and promotes the wear of these tapered roller bearings 12 and 13. Especially,
In the case of the tapered roller bearing 12 located on the ring gear 5 side, since the applied load is large, the influence of the foreign matter mixed in the lubricating oil 20 increases, which may cause a serious problem such as shortening of the service life.

Accordingly, an object of the present invention is to solve the above problems, and it is possible to suppress an excessive supply of lubricating oil to a tapered roller bearing that rotatably supports a pinion shaft, thereby reducing production costs. An object of the present invention is to provide a bearing device for a pinion shaft for a final reduction gear, which can prevent a reduction in the bearing life of a tapered roller bearing without causing an increase in the bearing speed.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to provide a pair of tapered roller bearings in which a shaft of a pinion shaft meshing with a ring gear rotatably provided in a housing is supported by a bearing support of the housing. A bearing device for a final reduction gear having an inner ring spacer for maintaining a constant interval between inner rings of these combined tapered roller bearings, wherein at least an outer peripheral portion of the inner ring spacer has at least a ring gear-side tapered roller bearing. The present invention is attained by a bearing device for a pinion shaft for a final reduction gear, characterized in that a bulging portion for narrowing a gap with an outer ring or a bearing support portion and restricting a flow amount of lubricating oil is formed.

According to the above configuration, at least the tapered roller bearing on the ring gear side has a swelling portion provided on the outer peripheral portion of the inner ring spacer to narrow a gap serving as a supply path for guiding lubricating oil to the small diameter side of the tapered rollers. Therefore, the amount of the lubricating oil is suppressed, and it is possible to suppress the excessive supply of the lubricating oil as the rotation speed of the pinion shaft increases. Further, since only the shape of the inner ring spacer conventionally provided is changed, the number of parts and the number of assembly steps of the bearing device do not increase.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bearing device for a pinion shaft for a final reduction gear according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of a main part of a vehicle final reduction gear 30 according to a first embodiment of the present invention.

The final reduction gear 30 for a vehicle according to the first embodiment.
Has substantially the same configuration as the conventional final deceleration device 1 for a vehicle shown in FIG. 9, and therefore, the same components are denoted by the same reference numerals and detailed description thereof will be omitted. The vehicle final reduction gear 30
The outer ring 12 so that the small diameter sides of the tapered rollers face each other.
a, 13a are bearing bearings 4a, 4 in the housing 4;
b, a pair of tapered roller bearings 12, 13 whose inner races 12b, 13b are inserted into the shaft portion 7 of the pinion shaft 10 and are rear-assembled to rotatably support the pinion shaft 10. The pair of tapered roller bearings 12, 13
A substantially cylindrical inner ring spacer which is fitted and fitted to the shaft portion 7 of the pinion shaft 10 at both ends and abuts the inner rings 12b, 13b at both ends to keep the distance between the inner rings 12b, 13b constant. The bearing device includes the spacer 31.

In the outer peripheral portion of the spacer 31, gaps 33, 3 serving as supply paths for guiding the lubricating oil 20 from the lubricating oil guide wall surface 22 to the tapered roller small diameter sides of the tapered roller bearings 12, 13 are provided.
A bulging portion 36 that narrows 4 is formed. In the case of the first embodiment, the bulging portion 36 is formed by increasing the thickness (increase in diameter) of a certain range in the middle portion of the cylindrical spacer 31 in the outer diameter direction. The outer diameter of the bulging portion 36 is naturally set to be larger than the outer diameter of the small flanges 12c and 13c on the tapered roller small diameter side of the respective tapered roller bearings 12 and 13. In the case, each tapered roller bearing 1
The inner diameter of each of the cages 12d and 13d for positioning each tapered roller is set larger than the inner diameter of each of the tapered rollers 2 and 13.

As a result of the above setting, the outer peripheral surface of the bulging portion 36 is formed on the outer races 12a, 13 of the tapered roller bearings 12, 13.
A gap as a supply passage formed between the small diameter inner peripheral surfaces of the bearing support portions 4a and 4b approaching the small diameter side of the bearing support portions 4a and 4b that support the bearing a. 33,3
4 is narrowing. The amount of lubricating oil supply necessary for the tapered roller bearings 12 and 13 to operate stably and continuously is calculated in advance, and actually flows into the tapered roller bearings 12 and 13 at any rotational state. The gaps 33 and 34 are set so that the amount of lubricating oil does not fall below a necessary minimum.

In the vehicle final reduction gear 30 of the first embodiment described above, the tapered roller bearing 1
The gaps 33 and 34 serving as supply paths for guiding the lubricating oil 20 to the small-diameter side of the tapered roller 2 and 13 are formed by bulging portions 36 provided on the spacer 31 provided between the inner rings 12 b and 13 b of the tapered roller bearings 12 and 13. The pinion shaft 1
With an increase in the rotation speed of 0, the amount of lubricating oil supplied to the lubricating oil guide wall surface 22 by the jumping up by the ring gear 5 increases, and at the same time, the pumping action in each of the tapered roller bearings 12 and 13 increases. The amount of lubricating oil for each of the tapered roller bearings 12 and 13 is suppressed, and it is possible to suppress the excessive supply of the lubricating oil 20 due to the high-speed rotation of the pinion shaft 10.

Accordingly, it is possible to prevent the contact with the foreign matter mixed in the lubricating oil 20 from being activated by excessive lubrication, and to suppress the abrasion caused by the contact with the foreign matter mixed in the lubricating oil 20,
The life of the tapered roller bearings 12, 13 can be prevented from being shortened. Further, since the above-described effects can be obtained only by changing the shape of the conventionally equipped spacer, the number of parts and the number of assembling steps do not increase, and the production cost does not increase.

Hereinafter, the second to eighth embodiments of the present invention will be sequentially described. The same components as those in the above-described first embodiment and the conventional example are denoted by the same reference numerals, and description thereof will be omitted or omitted. Simplify. FIG. 2 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle 40 according to a second embodiment of the present invention.

The vehicle final reduction gear 40 of the second embodiment
The structure of the housing 4 is such that the retainer 6, which is screwed to the housing main body, is provided with bearing supports 4a, 4b, as shown in FIG.
A bulging portion 42 is formed at the center on the outer peripheral side of the spacer 41 disposed between the pair of tapered roller bearings 12, 13, and the bulging portion 42 separates the tapered roller bearings 12, 12 from the lubricating oil guide wall surface 22. As in the case of the first embodiment, the gaps 43 and 44 serving as the supply paths for guiding the lubricating oil 20 to the small diameter side of the tapered roller 13 are narrowed by the bulging portion 42.

Also, in the case of the second embodiment, the bulging portion 42 is formed by increasing the thickness of the middle portion of the cylindrical spacer 41 in the outer diameter direction (increase the diameter). Bulge 4
2 are tapered roller bearings 12, 13
Are set larger than the inner diameters of the retainers 12d and 13d. Therefore, the bearing device according to the second embodiment also includes the first device.
The same operation and effect as the bearing device of the embodiment can be obtained.

FIG. 3 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle 50 according to a third embodiment of the present invention. The final deceleration device for a vehicle 50 of the third embodiment has the same structure of the housing 4 as that of the first embodiment. Further, in the case of the third embodiment, the point that the bulging portion 52 is formed at the center on the outer peripheral side of the spacer 51 provided between the pair of tapered roller bearings 12 and 13 is the same as the case of each of the above embodiments. However, the shape of the bulging portion 52 is devised.

That is, in the case of the third embodiment, the spacer 5
The bulging portion 52 formed in the shape 1 is provided in a flange shape in a range facing the inner peripheral surface of the bearing support portion 4a, and the tapered roller small diameter of the tapered roller bearing 12 on the pinion gear 8 side from the lubricating oil guide wall surface 22. Only the gap 53 serving as a supply path for guiding the lubricating oil 20 to the side is narrowed. The outer diameter of the bulging portion 52 is set to be larger than the inner diameter of the cage 12d of the tapered roller bearing 12.

That is, abrasion of the tapered roller bearing due to excessive lubrication of the lubricating oil 20 containing foreign matter is likely to occur in the tapered roller bearing 12 on the pinion gear 8 side where a large load is applied. Therefore, as in the third embodiment, even if only the gap 53 serving as the supply path of the lubricating oil to the tapered roller bearing 12 on the pinion gear 8 side is narrowed, excessive lubrication to the tapered roller bearing 12 on the pinion gear 8 side is prevented. Thus, the life of the tapered roller bearing 12 can be prevented from being shortened, and the original object of preventing the life of the tapered roller bearing that supports the shaft portion 7 of the pinion shaft 10 from being shortened can be achieved.

FIG. 4 is a longitudinal sectional view of a main part of a final speed reducer 60 for a vehicle according to a fourth embodiment of the present invention. The vehicle final deceleration device 60 of the fourth embodiment has a structure of the housing 4,
As in the second embodiment, the retainer 6 is screwed to the housing body and has a structure in which the bearing supports 4a and 4b are provided.

The bulging portion 62 formed on the outer periphery of the spacer 61 protrudes toward the inner peripheral surface of the bearing support 4a that supports the outer ring 12a of the tapered roller bearing 12 on the pinion gear 8 side. Only the gap 63 serving as a supply path for guiding the lubricating oil 20 from the lubricating oil guide wall surface 22 to the tapered roller small diameter side of the tapered roller bearing 12 on the pinion gear 8 side is narrowed. The outer diameter of the bulging portion 62 is determined by the tapered roller bearing 12.
Is set larger than the inner diameter of the retainer 12d. Also in this case, similarly to the case of the third embodiment, it is possible to suppress excessive lubrication to the tapered roller bearing 12 on the pinion gear 8 side, and to prevent the life of the tapered roller bearing 12 from being shortened.

FIG. 5 is a longitudinal sectional view of a main part of a final speed reducer 70 for a vehicle according to a fifth embodiment of the present invention. In the vehicle final reduction gear 70 of the fifth embodiment, the structure of the housing 4 is the same as that of the first embodiment. In the case of the fifth embodiment, the bulging portion 7 formed on the outer periphery of the spacer 71 is used.
2 is an outer ring 12 of the tapered roller bearing 12 on the pinion gear 8 side.
a of the tapered roller bearing 12 protrudes from the lubricating oil guide wall surface 22 on the pinion gear 8 side so as to approach both the inner peripheral surface of the bearing support portion 4a supporting the a and the end surface of the outer ring 12a. Only the gap 73 serving as a supply path for guiding the lubricating oil 20 to the small diameter side is narrowed. The bulging portion 7
The outer diameter in 2 is set larger than the small inner diameter of the outer ring 12a of the tapered roller bearing 12. Also in this case, the third
The same operation and effect as in the embodiment can be obtained.

FIG. 6 is a longitudinal sectional view of a main part of a final speed reducer 80 for a vehicle according to a sixth embodiment of the present invention. In the vehicle final reduction gear 80 of the sixth embodiment, the structure of the housing 4 is as follows.
As in the second embodiment, the retainer 6 is screwed to the housing body and has a structure in which the bearing supports 4a and 4b are provided.

In the case of the sixth embodiment, the bulging portion 82 formed on the outer periphery of the spacer 81 has the tapered roller bearing 1 on the pinion gear 8 side as in the case of the fifth embodiment.
The outer ring 12a protrudes so as to approach both the inner peripheral surface of the bearing support portion 4a supporting the outer ring 12a and the end surface of the outer ring 12a.
Only the gap 83 serving as a supply path for guiding the lubricating oil 20 to the tapered roller small diameter side of the tapered roller bearing 12 on the side is narrowed. The outer diameter of the bulging portion 82 is set to be larger than the small inner diameter of the outer ring 12a of the tapered roller bearing 12. In this case, the same operation and effect as those of the third embodiment can be obtained.

FIG. 7 is a longitudinal sectional view of a main part of a final speed reducer 90 for a vehicle according to a seventh embodiment of the present invention. In the vehicle final reduction gear device 90 of the seventh embodiment, the structure of the housing 4 is the same as that of the first embodiment. In the case of the seventh embodiment, the bulging portion 92 provided on the outer periphery of the spacer 91 is provided.
Is the outer ring 12a of the tapered roller bearing 12 on the pinion gear 8 side.
The protrusion protrudes toward the inner peripheral surface of the bearing support portion 4a supporting the lubricating oil, and serves as a supply path for guiding the lubricating oil 20 from the lubricating oil guide wall surface 22 to the tapered roller small diameter side of the tapered roller bearing 12 on the pinion gear 8 side. Only 93 is narrowed. The outer diameter of the bulging portion 92 is set to be larger than the inner diameter of the retainer 12d of the tapered roller bearing 12. Again,
Excessive lubrication to the tapered roller bearing 12 on the pinion gear 8 side can be suppressed, and a reduction in the life of the tapered roller bearing 12 can be prevented.

FIG. 8 is a longitudinal sectional view of a main part of a final speed reducer 100 for a vehicle according to an eighth embodiment of the present invention. The vehicle final deceleration device 100 according to the eighth embodiment has a housing 4 having a structure in which bearings 4a and 4b are provided on a retainer 6 screwed to the housing main body as in the second embodiment. It was done.

In the case of the eighth embodiment, the bulging portion 102 provided on the outer periphery of the spacer 101 is provided in the bearing support 4a supporting the outer ring 12a of the tapered roller bearing 12 on the pinion gear 8 side. It protrudes toward the circumference,
Only the gap 103 serving as a supply passage for guiding the lubricating oil 20 from the lubricating oil guide wall surface 22 to the tapered roller small diameter side of the tapered roller bearing 12 on the pinion gear 8 side is narrowed. In addition, the swelling portion 10
The outer diameter of 2 is set larger than the inner diameter of the cage 12d of the tapered roller bearing 12. Also in this case, the third
The same operation and effect as in the embodiment can be obtained. It should be noted that the bearing device of the present invention is not limited to the shape of each of the above embodiments, and the configuration of the final reduction gear, the shape of the inner ring spacer, and the like can be appropriately changed based on the gist of the present invention. Needless to say.

[0037]

According to the bearing device of the pinion shaft for the final reduction gear of the present invention, at least the tapered roller bearing on the ring gear side is provided on the small diameter side of the tapered roller by the bulging portion provided on the outer peripheral portion of the inner ring spacer. Since the gap serving as the supply path for introducing the lubricating oil is narrowed, the amount of the lubricating oil is suppressed, and it is possible to suppress the excessive supply of the lubricating oil as the rotation speed of the pinion shaft increases. Therefore, the chance of contact between the foreign matter and the tapered roller bearing can be reduced, and wear of the tapered roller bearing can be reduced. Further, since only the shape of the inner ring spacer conventionally provided is changed, the number of parts and the number of assembly steps of the bearing device do not increase. Therefore, it is possible to provide a bearing device for a pinion shaft for a final reduction gear, which can prevent a reduction in the bearing life of the tapered roller bearing without increasing production costs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part of a final reduction gear for a vehicle according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a fourth embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a fifth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a sixth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to a seventh embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a main part of a final reduction gear for a vehicle according to an eighth embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a main part of a conventional final reduction gear for a vehicle.

FIG. 10 is a longitudinal sectional view of a main part of another conventional final reduction gear for a vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Final reduction gear for vehicles 4 Housing 4a, 4b Bearing support 5 Ring gear 7 Shaft 8 Pinion gear 9 Companion flange 10 Pinion shaft 12, 13 Tapered roller bearing 12a, 13a Outer ring 12b, 13b Inner ring 16 Tightening nut 14 Oil seal 20 Lubricating oil 22 Lubricating oil guide wall surface 30 Final reduction gear for vehicle 33, 34 Gap 36 Swelling part

Claims (1)

[Claims] 1. A space between a pair of tapered roller bearings that supports a shaft portion of a pinion shaft meshing with a ring gear rotatably provided in a housing to a bearing support portion of the housing, and inner rings of the tapered roller bearings combined in a back side. And an inner ring spacer that keeps a constant distance between the inner ring spacer and the outer ring of the inner ring spacer, at least a gap between the outer ring or the bearing support of the tapered roller bearing on the ring gear side is reduced. A pinion shaft bearing for a final reduction gear, wherein a bulging portion for limiting a flow rate of lubricating oil is formed.