JP2003148458A - Bearing unit for supporting pinion shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent assemblage, reduce a rotational torque to increase the efficiency of a differential device, and reduce an axial length to downsize the differential device in a bearing unit 20 for supporting a pinion shaft for rotatably supporting the pinion shaft 4 forming the differential device of automobile on the inside of a differential case 1. SOLUTION: This bearing unit 20 for rotatably supporting the pinion shaft 4 on the differential case 1 comprises a pair of angular ball bearings 5 and 6 arranged parallel with each other in the axial direction of the pinion shaft 4. The angular ball bearings 6 on a pinion gear side comprise double-row ball groups 32 and 33, and a ball group 32 on the pinion gear side is of a tandem type positioned on the radial outer side. The outer ring 26 of the angular ball bearings 5 and 6 is formed of a single outer ring fixed to the differential case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pinion shaft supporting bearing unit for rotatably supporting a pinion shaft, which constitutes a differential device of an automobile, inside a differential case.

[0002]

2. Description of the Related Art The structure of a conventional differential device is shown in FIG.

In FIG. 4, reference numeral 1 denotes a differential case. In the differential case 1, a differential transmission mechanism 2 for differentially interlocking left and right wheels, a pinion gear 3, a pinion shaft 4, and a pinion shaft 4 are rotatably supported. The tapered roller bearings 50, 60 and the like are housed therein.

The pinion gear 3 meshes with the ring gear 2a of the differential transmission mechanism 2 and is integrally formed with the inner end portion of the pinion shaft 4.

The pinion shaft 4 is rotatably supported inside the differential case 1 by means of single-row tapered roller bearings 50 and 60 arranged so as to face each other.
A companion flange 7 to which a propeller shaft (not shown) is connected is provided at the outer end portion.

Further, the tapered roller bearings 50 and 60 are each made of a forged bearing case portion 1 of the differential case 1.
It is mounted on the inner peripheral surface of the bearing mounting annular walls 13, 14 formed in a. The tapered roller bearing 50 on the companion flange side is installed from the small diameter side opening of the bearing case portion 1a, and the tapered roller bearing 60 on the pinion gear side is installed from the large diameter side opening of the bearing case portion 1a. A spacer 8 for positioning is interposed between 50 and 60. The tapered roller bearings 50 and 60 are fixed by applying a sufficient preload between the pinion gear 3 and the companion flange 7 by screwing a nut 15 onto the outer end portion of the pinion shaft 4 and fastening the nut 15 to the companion flange 7. It

Further, lubricating oil is stored at a level L in the differential case 1 when the operation is stopped. The oil is the ring gear 2a during operation.
Of the bearing case portion 1a, is guided up to the tapered roller bearings 50 and 60 through the oil introduction passage 11 formed between the annular walls 13 and 14 in the bearing case portion 1a, and further to an oil return passage (not shown). Returned through. The pinion shaft 4
An oil seal 9 for preventing oil leakage is attached between the outer peripheral surface on the outer end side and the inner peripheral surface of the bearing case 1a, and a seal protection cup for concealing the oil seal 9 is provided. 10 is attached.

[0008]

In the case of the conventional differential device, since the bearing that rotatably supports the pinion shaft 4 is the tapered roller bearings 50 and 60, the rotational torque becomes large and the efficiency of the differential device decreases. There was a problem.

Further, in order to reduce the rotational torque acting on the tapered roller bearings 50 and 60 as much as possible and extend the bearing life, a spacer 8 is interposed between the tapered roller bearings 50 and 60 to form the tapered roller bearing 50. , 60 has been devised to increase the interval, but as a result, the length in the axial direction becomes large, which causes a problem that the differential device becomes large.

Further, the nut 1 is attached to the companion flange 7.
The preload is applied to the tapered roller bearings 50 and 60 by fastening No. 5, and proper preload adjustment work is required when assembling the differential device, which increases the number of assembly steps.
There was a problem of poor assembly.

The present invention provides a bearing unit for supporting a pinion shaft, which is excellent in assemblability, has a small rotating torque, improves the efficiency of the differential device, and has a small axial length, and can be downsized. The purpose is to do.

[0012]

SUMMARY OF THE INVENTION The present invention provides a unit that rotatably supports the pinion shaft with respect to a case between a pinion gear provided at one end of the pinion shaft and a companion flange provided at the other end. A bearing unit for supporting a pinion shaft, which comprises a pair of angular ball bearings arranged side by side in the axial direction of the pinion shaft, and the companion flange in the pinion gear direction by a fastening means. It is fixed to the pinion shaft by applying a preload by fastening, and each angular ball bearing has an inner ring mounted on the outer peripheral surface of the pinion shaft, and an outer ring concentrically rotatably arranged on the outer periphery of the inner ring. , A ball group interposed between the inner ring and the outer ring, the angular contact ball bearing on the pinion gear side has a double row ball group,
In addition, the ball group on the pinion gear side is a tandem type in which the ball group is located radially outward, and the outer ring of each angular ball bearing is formed by a single outer ring fixed to the case.

According to the bearing unit for supporting the pinion shaft of the present invention, since the bearing that rotatably supports the pinion shaft with respect to the case is unitized by a single outer ring, preload adjustment is possible. It can be performed accurately at the manufacturing stage of the bearing unit, preload adjustment work is not required at the time of assembling the differential device, the number of assembling steps can be reduced, and the assemblability is improved.

Further, the bearing unit is composed of a pair of angular contact ball bearings having a small frictional resistance, and the rotating torque becomes smaller than that of the tapered roller bearing. In addition, the number of balls in the ball group on the pinion gear side can be increased by making the angular contact ball bearing on the pinion gear side, which is subject to a large thrust load, double rows, and by adopting the tandem type ball group on the pinion gear side located radially outward. The load capacity is increased. Therefore, sufficient load capacity can be obtained while reducing the rotating torque, and the efficiency of the differential device is improved.

Further, since the bearing unit is composed of a pair of angular contact ball bearings, it is not necessary to increase the distance between the bearings to reduce the rotating torque as in the tapered roller bearing, and it is possible to reduce the length in the axial direction and to make the differential. The size of the device can be reduced.

The companion flange side of the pinion shaft has a small diameter so that the bearing unit can be press-fitted from the companion flange side of the pinion shaft, and a fixing flange for fixing to the outer surface of the case is provided on the outer peripheral surface of the outer ring. May be.

Since the bearing unit is fixed to the outer surface of the case as described above, the case can be made smaller than the case covering the bearing unit.

Further, both ends in the axial direction may be hermetically sealed with seal members to provide grease lubrication.

By using grease lubrication in this way,
Since it is not necessary to form an oil introduction path or an oil return path in the differential case, the differential device can be downsized. Moreover, unlike the oil lubrication, it is not affected by foreign matter in the oil of the differential device, so that the life of the bearing is improved.

Further, the inner ring of the angular ball bearing on the companion flange side may be formed integrally with the companion flange, the inner ring of the angular ball bearing on the pinion gear side may be formed integrally with the pinion shaft, or the angular ring on the companion flange side may be formed integrally. The inner ring of the ball bearing may be formed integrally with the companion flange, and the inner ring of the angular ball bearing on the pinion gear side may be formed integrally with the pinion shaft.

By thus forming the inner ring of the angular ball bearing integrally with the companion flange or the pinion shaft, the number of parts can be reduced and the cost can be reduced.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 shows a sectional view of a bearing unit portion for supporting a pinion shaft of a differential device according to the first embodiment.

In FIG. 1, 1 is a differential case, 3 is a pinion gear meshing with a ring gear (not shown) of a differential transmission mechanism, 4 is a pinion shaft integrally formed with the pinion gear 3, and 20 is a differential case 1 with a pinion shaft 4. The bearing unit rotatably supports the bearing unit.

The bearing unit 20 is composed of a single row angular ball bearing 5 on the companion flange side and a tandem type double row angular ball bearing 6 on the pinion gear side. That is, the angular ball bearing 5 includes an inner ring 21, an outer ring 26, a ball group 31, and a cage 34, and the angular ball bearing 6 includes an inner ring 22, an outer ring 26, a group of balls 32, 33, and cages 35, 36. Both inner rings 21 and 22 are abutted in the axial direction, and the outer ring 26 is formed as a single unit.

The inner ring 22 is arranged radially outside the inner ring 21. Further, raceways 23, 24, 25 are formed on the outer peripheral surfaces of the inner races 21, 22 respectively, and the raceway 24 on the pinion gear side of the inner race 22 is located radially outside of the other raceway 25. Further, raceways 27, 28, 29 are formed on the inner peripheral surface of the outer ring 26 so as to face the raceways 23, 24, 25, and a fixing flange 30 is projectingly provided on the outer peripheral surface of the companion flange side. ing.

Then, the tracks 23, 2 of the inner rings 21, 22
4, 25 and the balls 3 held by the cages 34, 35, 36 along the tracks 27, 28, 29 of the outer ring 26, respectively.
1, 32, 33 are arranged, grease is filled, and both ends in the axial direction are sealed by the seal members 37, 38. Since the raceway 24 of the inner ring 22 is located radially outside of the raceway 25, the raceway 24 becomes long and the ball group 3 on the pinion gear side 3
You can increase the number of 2 balls.

The bearing unit 20 is manufactured by the inner ring 2 at the manufacturing stage.
Accurate preload adjustment is performed by assembling the ball groups 31, 32, 33 held by the outer races 1, 22, the outer ring 26, and the cages 34, 35, 36.

Further, the pinion shaft 4 has a large diameter portion 42 and a medium diameter portion 4 whose outer diameters gradually increase toward the pinion gear side.
3 and the small diameter portion 44.

The bearing unit 20 is press-fitted into the pinion shaft 4 from the drive shaft side, the inner ring 22 is externally fitted to the large diameter portion 42 of the pinion shaft 4, and the inner ring 21 is externally fitted to the medium diameter portion 43. Also, the outer ring 2 is attached to the outer surface of the differential case 1.
6 abutting the flange 30 and bolt 40 to the flange 30.
And fasten it to the differential case 1.

Further, the companion flange 7 is spline-fitted to the small diameter portion 44 of the pinion shaft 4, and the pinion shaft 4
The end portion of the drive shaft on the outside is deformed radially outward and caulked to the companion flange 7, and the caulking 41 serving as the fastening means sandwiches the bearing unit 20 between the pinion gear 3 and the companion flange 7 to apply a preload. Fix it. A packing 39 is provided between the outer ring 26 and the differential case 1 to prevent oil in the differential device from leaking.

According to the bearing unit for supporting the pinion shaft thus constructed, the bearing for rotatably supporting the pinion shaft 4 with respect to the differential case 1 is unitized by the single outer ring 26. Because
Preload adjustment can be accurately performed at the manufacturing stage of the bearing unit 20,
Pre-load adjustment work is not required at the time of assembling the differential device, the number of assembling steps can be reduced, and assemblability is improved.

Further, the bearing unit 20 is composed of a pair of angular contact ball bearings 5 and 6 having a small frictional resistance, the rotational torque becomes smaller than that of the tapered roller bearing, and the efficiency of the differential device is improved.

Further, the angular ball bearing 6 on the pinion gear side on which a large thrust load acts is arranged radially outside of the angular ball bearing 5 on the companion flange side, and the angular ball bearing 6 on the pinion gear side is a double row, and Since the ball group 32 on the pinion gear side is a tandem type that is positioned radially outward, the number of balls in the ball group 32 on the pinion gear side can be increased. Therefore, the load capacity on the side of the pinion gear on which a large thrust load acts becomes large, sufficient support rigidity can be obtained even with a ball bearing, and the bearing performance is improved.

The bearing unit 20 is composed of a pair of angular contact ball bearings 5 and 6, and unlike the tapered roller bearing, it is not necessary to increase the distance between the bearings to reduce the rotational torque, and the axial length is reduced. Therefore, the differential device can be downsized.

Since the fastening means is the caulking 41,
The work of screwing the pinion shaft 4 is not necessary, the processing cost can be reduced, and the weight can be reduced.

Further, the bearing unit 20 is grease lubrication in which both ends in the axial direction are sealed by the seal members 37 and 38, and like the conventional oil lubrication, an oil introduction passage and an oil return passage are provided in the differential case 1. Therefore, the differential device can be made smaller and lighter. Moreover, since the bearing unit 20 is not affected by foreign matter in the oil of the differential device, the bearing life is improved.

Further, the pinion shaft 4 has a smaller diameter toward the companion flange side, the bearing unit 20 is press-fitted into the pinion shaft 4 from the drive shaft side, and the flange 30 is attached to the outer surface of the differential case 1 by the bolt 40.
Since the bearing unit 20 is not required to be covered with the differential case 1, the size of the differential case 1 can be reduced.

Further, the bearing unit 20 has a flange 30.
Is fixed to the outer surface of the differential case 1 by bolts, and the angular ball bearing 5 on the companion flange side is not covered with the differential case 1. Therefore, the inner ring 21 and the outer ring 26 of the angular contact ball bearing 5 can be bulged outward in the radial direction so that the diameters of the raceways 23, 27 can be increased, and the number of balls in the ball group 31 can be increased to increase the load capacity. it can.

The fastening means is not limited to the caulking 41, but may be a nut. (Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention.
Will be explained. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The second embodiment is characterized in that the inner ring of the angular contact ball bearing 5 on the drive shaft side of the bearing unit 20 is formed integrally with the companion flange 7.

That is, the raceway 23 is formed on the outer peripheral surface of the companion flange 7, and the angular ball bearing 5 is constituted by the companion flange 7, the outer ring 26, and the ball group 31 held by the cage 34. The angular ball bearing 6 on the pinion gear side is the same as in the first embodiment.

The bearing unit 20 is manufactured at the manufacturing stage.
2, the outer ring 26, the ball groups 31, 32, 33 held by the cages 34, 35, 36, and the companion flange 7 are assembled to perform accurate preload adjustment.

To mount the bearing unit 20, the inner ring 22 is press-fitted into the pinion shaft 4 from the drive shaft side, the companion flange 7 is spline-fitted to the pinion shaft 4, and the nut 15 is attached to the end of the pinion shaft 4 on the drive shaft side. Fasten and secure by applying preload.

According to the bearing unit for supporting the pinion shaft thus configured, in addition to the effect described in the first embodiment, the inner ring of the angular ball bearing 5 and the companion flange 7 are integrally formed, so that the number of parts is reduced. It is possible to obtain the effect that the cost can be reduced.

Furthermore, since the companion flange 7 also serves as the inner ring of the angular ball bearing 5, even if the length of the companion flange 7 is shortened, the length of the spline 71 necessary for transmitting the rotational torque can be sufficiently secured. , Further downsizing and weight reduction of the differential device can be achieved.

The fastening means is not limited to the nut 15 and may be caulking. (Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention.
Will be explained. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the third embodiment, the inner ring of the angular ball bearing 5 on the drive shaft side of the bearing unit 20 is formed integrally with the companion flange 7, and the inner ring of the angular ball bearing 6 on the pinion gear side is integrated with the pinion shaft 4. It is characterized by being formed.

That is, the raceway 23 is formed on the outer peripheral surface of the companion flange 7, and the angular ball bearing 5 is constituted by the companion flange 7, the outer ring 26, and the ball group 31 held by the cage 34. Also, on the outer peripheral surface of the pinion shaft 4,
A pair of raceways 24, 25 having a large diameter on the pinion gear side are formed, and the angular ball bearing 6 is connected to the pinion shaft 4, the outer ring 2
6, a group of balls 32 and 33 held by holders 35 and 36.

The bearing unit 20 is manufactured by the outer ring 2 at the manufacturing stage.
6, ball group 31, 3 held by cage 34, 35, 36
Accurate preload adjustment is performed by assembling 2, 33 and the companion flange 7.

The bearing unit 20 is mounted by mounting the ball groups 32 and 33 from the drive shaft side on the track 2 of the pinion shaft 4.
4 and 25, the companion flange 7 is spline-fitted to the pinion shaft 4, and a nut 15 is fastened to the end of the pinion shaft 4 on the drive shaft side to apply a preload to fix it.

According to the bearing unit for supporting a pinion shaft constructed as described above, in addition to the effect described in the first embodiment, the inner ring of the angular ball bearing 5 and the companion flange 7 are integrally formed, and the angular ball bearing is also formed. Since the inner ring 6 and the pinion shaft 4 are integrally formed, the number of parts can be reduced and the cost can be reduced.

Further, since the companion flange 7 also serves as the inner ring of the angular ball bearing 5, even if the length of the companion flange 7 is shortened, the length of the spline 71 necessary for transmitting the rotational torque can be sufficiently secured. , Further downsizing and weight reduction of the differential device can be achieved.

Further, since the inner ring of the angular contact ball bearing 6 is integrally formed with the pinion shaft 4, the inner ring becomes unnecessary,
The diameter of the pinion shaft 4 is increased, and the strength of the pinion shaft 4 is improved. Moreover, since there is no inner ring of the angular ball bearing 6, the problem of variation in the clearance due to the fitting with the pinion shaft 4 does not occur, the rigidity is improved, and the bearing life is improved.

The fastening means is not limited to the nut 15 and may be caulking.

The inner ring of the angular ball bearing 6 on the pinion gear side is formed integrally with the pinion shaft 4, and the inner ring of the angular ball bearing 5 on the drive shaft side is formed separately from the companion flange 7 as shown in FIG. It may have been done.

The present invention is not limited to the above-mentioned embodiment, and various applications and modifications can be considered. (1) In the present invention, as shown in the above-described embodiment, the pinion gear side angular contact ball bearing 6 is a two-row tandem type angular contact ball bearing, but the invention is not limited to two rows, and the pinion gear side is not limited. The ball group may be formed of three or more rows of balls arranged so that the ball group is positioned radially outward. (2) In the present invention, as shown in the above embodiment, the drive shaft side angular contact ball bearing 5 is a single row, but it may be a tandem type double row angular contact ball bearing. (3) The present invention is not limited to grease lubrication as shown in the above-described embodiment, but an oil introduction passage and an oil return passage are formed in the outer ring 26 to obtain the oil lubrication as shown in FIG. Good.

[0058]

According to the bearing unit for supporting a pinion shaft of the present invention, the assembling property is excellent, the rotating torque is small, the efficiency of the differential device is improved, and the axial length is small, and the differential device is small. The effect that it can be achieved is obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a bearing unit for supporting a pinion shaft of a differential device according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a bearing unit for supporting a pinion shaft of a differential gear in Embodiment 2 of the present invention.

FIG. 3 is a partial cross-sectional view of a bearing unit for supporting a pinion shaft of a differential device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a differential device in a conventional example.

[Explanation of symbols]

1 differential case 2 differential transmission 2a ring gear 3 pinion gear 4 pinion shaft 5 Angular contact ball bearing on companion flange side 6 Angular contact ball bearing on the pinion gear side 7 companion flange 20 bearing unit 21,22 inner ring 26 outer ring 31, 32, 33 balls 15 Nut (fastening means) 41 Caulking (fastening means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirofumi Hyakuji             3-5-8 Minamisenba, Chuo-ku, Osaka Koyo             Within Seiko Co., Ltd. F term (reference) 3J012 AB04 BB03 CB01 CB10 EB14                       FB08 FB10 HB01 HB02                 3J017 AA02 BA10 CA04 DA01 DB02                       DB08 HA02                 3J063 AA02 AB04 AC01 BA01 BB41                       CA05 CB17 CD02 CD06 CD09                       CD42 XA11                 3J101 AA02 AA44 AA54 AA62 AA72                       AA82 BA64 BA65 EA63 FA41                       FA46 FA53 GA11

Claims (6)

[Claims] 1. A pinion comprising a pinion gear provided at one end of a pinion shaft and a companion flange provided at the other end of which a unitized bearing for rotatably supporting the pinion shaft with respect to a case is mounted. A bearing unit for shaft support, comprising a pair of angular ball bearings arranged side by side in the axial direction of the pinion shaft, and applying a preload by fastening the companion flange in the pinion gear direction by fastening means. Fixed to the pinion shaft, each of the angular ball bearings includes an inner ring mounted on an outer peripheral surface of the pinion shaft, an outer ring concentrically rotatably arranged on the outer periphery of the inner ring, and a space between the inner ring and the outer ring. The pinion gear side angular contact ball bearing has a double row of ball groups, and the pinion gear side ball group is positioned radially outward. A tandem type bearing unit for supporting a pinion shaft, wherein the outer ring of each angular ball bearing is formed by a single outer ring fixed to the case. 2. The bearing unit has a small diameter on the companion flange side of the pinion shaft so that the bearing unit can be press-fitted from the companion flange side of the pinion shaft, and a fixing flange protruding from the outer peripheral surface of the outer ring is fixed to the outer surface of the case. The bearing unit for supporting a pinion shaft according to claim 1, wherein 3. A bearing unit for supporting a pinion shaft according to claim 1, wherein both ends in the axial direction are sealed with a seal member for grease lubrication. 4. The bearing unit for supporting a pinion shaft according to claim 1, wherein the inner ring of the angular ball bearing on the companion flange side is formed integrally with the companion flange. 5. The bearing unit for supporting a pinion shaft according to claim 1, wherein the inner ring of the angular ball bearing on the pinion gear side is formed integrally with the pinion shaft. 6. The inner ring of the angular ball bearing on the companion flange side is formed integrally with the companion flange,
The bearing unit for supporting a pinion shaft according to claim 1, wherein the inner ring of the angular ball bearing on the pinion gear side is formed integrally with the pinion shaft.