JPH11201151A - Tapered roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smooth axial movement of a tapered roller during running-in. SOLUTION: By respectively deviating the apexes of crowning of a raceway surfaces 1a, a raceway surface 2a, and a rolling surface 3c from an axial center to the large part side, a contact part central position C between an orbit surface 1a, and a raceway 2a and a rolling surface 3c is deviated from the axial center (a position being 1/2 of length L) of a tapered roller 3 to the large part side by a given amount α.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapered roller bearing incorporated in a gear device such as a differential or a transmission of an automobile.

[0002]

2. Description of the Related Art For example, in an automobile driven by a front engine rear wheel, an engine, a clutch and a transmission are concentrated in a front part of a vehicle body, and a differential and a drive shaft are concentrated in a rear part of the vehicle body. Is used. The rotational power of the engine is reduced by the transmission (transmission) and transmitted to the propeller shaft,
It is input to a differential (final reduction gear) via a propeller shaft. The differential is composed of a reduction gear unit and a differential unit. The reduction gear unit reduces the rotational speed and increases the driving force. In particular, in the case of a vehicle with an engine installed vertically, the transmission direction is changed to the direction perpendicular to the driving force transmission direction and transmitted to the driving wheel axle. However, the differential device has a function of, when a rotational speed difference occurs between the left and right drive wheels, making both wheels differential to prevent the wheels from slipping.

FIG. 4 shows an example of the configuration of a differential. In the figure, the upper direction is the front of the vehicle body, and the lower direction is the rear of the vehicle body. A drive pinion shaft 22 is inserted through a front inner peripheral surface of the differential case 21 and is rotatably supported by a pair of tapered roller bearings 23 and 24. A propeller shaft is connected to the front end of the drive pinion shaft 22, and a drive pinion gear (reduction small gear) 22 a meshing with a link gear (reduction large gear) 25 is fixed or integrally provided at the rear end.

[0004] The link gear 25 is connected to a differential gear case 26, and the differential gear case 26 is formed of a pair of tapered roller bearings 2.
At 7 and 28, it is rotatably supported with respect to the differential case 21. Inside the differential gear case 26, a pair of pinion gears 29 and a pair of side gears 30 meshing therewith are disposed. The pinion gear 29 is fixed to a pinion shaft 31, and the side gear 30 is mounted on the differential gear case 26 via a thrust washer. The left and right drive shafts (not shown) are connected to the corresponding inner diameter portions of the side gears 30 (such as serration connection).

[0005] The driving torque of the propeller shaft is transmitted through a path of drive pinion gear 22a → link gear 25 → differential gear case 26 → pinion gear 29 → side gear 30 → drive shaft. On the other hand, the driving resistance of the tire is transmitted from the drive shaft → the side gear 30 → the pinion gear 29.

FIG. 6 shows a tapered roller bearing (23, 24, 27, 28) for rotatably supporting a rotating shaft (22, 26) with respect to a casing (21) in a differential as a gear device as described above. 1 is illustrated. The tapered roller bearing has an outer ring 11 having a conical raceway surface 11a, a conical raceway surface 12a, a small flange surface 12b on a small diameter side of the raceway surface 12a, and a large flange surface 12c on a large diameter side. Inner race 12 and raceway surface 11a of outer race 11
There are provided a plurality of tapered rollers 13 rotatably arranged between the tapered rollers 13 and a raceway surface 12a of the inner ring 12, and a retainer 14 for holding the tapered rollers 13 at predetermined circumferential intervals. Track surface 11
The a, the raceway surface 12a, and the rolling surface 13c are each provided with a crowning.

When using a bearing, the tapered rollers 13 are
a and the inner ring 1 by the combined force received from the raceway surface 12a.
2 and is rolled on the raceway surface while the large end surface 13a is contacted and guided by the large flange surface 12c. On the other hand, when the bearing is used, the small end surface 13b of the tapered roller 13 does not contact the small flange surface 12b of the inner ring 12, and there is a slight gap between the two.

The tapered roller bearing as described above is mounted on the cage 1
4. When the assembled body composed of the plurality of tapered rollers 13 and the inner ring 12 is inserted into the raceway surface 11a of the outer ring 11 from above with the small flange surface 12b side of the inner ring 12 facing downward, and assembled. In the state of time (initial state), tapered roller 1
3 does not sit at a regular position on the raceway surface (since the attitude of the tapered roller 13 at the time of insertion is not determined due to the degree of freedom with respect to the retainer 14 and the inner ring 12), and as shown in FIG. The end surface 13b comes into contact with the small flange surface 12b of the inner ring 12, and a gap δ is formed between the large end surface 13a and the large flange surface 12c. From this initial state, when the bearing is rotated a required number of times with the thrust load Fa applied, {FIG.
(C)｝, the tapered roller 13 moves axially toward the large flange surface 12c by the gap δ, the large end surface 13a comes into contact with the large flange surface 12c, and the tapered roller 13 is settled in a regular position.
(B)｝.

[0009]

In the initial state shown in FIG. 7 (a), when the bearing is fixed to the mounting portion of the mating device and a preload is set and the main operation is performed, the bearing moves toward the large flange surface 12c of the tapered roller 13. Preload loss occurs due to the axial movement of the bearing, and the required bearing function cannot be obtained. Therefore, conventionally, prior to the actual operation, the bearing in the initial state shown in FIG. 7A is temporarily assembled to the mounting portion of the counterpart device, and the tapered rollers 13 settle down to the regular positions shown in FIG. 7B. After driving in until
The bearing is fixed to the mounting portion and a predetermined preload is applied. In this case, if the tapered roller 13 is not smoothly moved in the axial direction toward the large end face 12c, a long running-in time is required until the tapered roller 13 is settled at a regular position, and the time required for completing the preload setting is required. Becomes longer.

[0010] Conventional tapered roller bearings include tapered rollers 13.
Rolling surface 13c and raceway surface 12a of inner and outer races 12, 11;
In the case where the axial movement of the tapered roller 13 during the running-in operation is not performed smoothly because the center position of the contact portion with the tape 11a is located at the axial center of the tapered roller 13 (a position １ ／ of the length L ′). And the running-in time tends to increase.

Therefore, the present invention provides a tapered roller which can be smoothly moved in the axial direction during running-in operation.
It is an object of the present invention to shorten the running-in time of this type of tapered roller bearing and to improve the efficiency of the preload setting operation.

[0012]

In order to achieve the above object, the present invention has an outer race having a conical raceway provided with a crowning, and a conical raceway provided with a crowning. An inner ring having a small flange surface on the small diameter side of the raceway surface and a large flange surface on the large diameter side, and a conical rolling surface provided with crowning, between the raceway surface of the outer ring and the raceway surface of the inner ring. In a tapered roller bearing having a plurality of rolling rollers arranged rotatably and a retainer for holding the tapered rollers at a predetermined circumferential interval, contact between a rolling surface of the tapered rollers and a raceway surface of an inner / outer ring. The center position of the section was shifted to the large diameter side from the axial center of the tapered rollers.

Here, crowning (convex crowning)
The term "provides a slight curvature to the generatrix of the raceway surface and the rolling surface" includes one having a single curvature and one having a plurality of curvatures (composite crowning).

Although the contact between the rolling surface and the raceway surface is a point contact in theory, the amount of crowning is extremely small, and therefore, in actuality, axial contact occurs in a region near the vertex of the crowning. In the present invention, the center position of the contact portion is defined for such a reason.

The center position of the contact portion between the rolling surface and the raceway surface is defined as the axial center of the tapered roller (L / L where L is the length of the tapered roller).
2), the number of running-in operations (the number of rotations of the bearing: the number of times of settling) from the initial state shown in FIG. 7A to the state shown in FIG. 7B was determined. The results shown were obtained.

As shown in FIG.
By displacing the bearing from the position No. 2 to the large diameter side, the number of times of settling of the bearing is reduced. The result was obtained. If the shift amount α exceeds 10%, smooth rolling of the tapered rollers may be affected, so the shift amount α is preferably kept within a range of 10% or less.

[0017]

Embodiments of the present invention will be described below.

As shown in FIG. 1, a tapered roller bearing according to this embodiment includes an outer ring 1 having a conical raceway surface 1a,
An inner ring 2 having a conical raceway surface 2a, a small flange surface 2b on the small diameter side of the raceway surface 2a, and a large flange surface 2c on the large diameter side;
A plurality of tapered rollers 3 having a conical rolling surface 3c and being rotatably disposed between a raceway surface 1a of the outer race 1 and a raceway surface 2a of the inner race 2, and a predetermined circumferential interval between the tapered rollers 3; And a retainer 4 for holding the same. Each of the raceway surface 1a, the raceway surface 2a, and the rolling surface 3c is provided with a crowning.

When the bearing is used, the tapered rollers 3 are pressed against the large flange surface 2c of the inner ring 2 by a combined force received from the raceway surface 1a and the raceway surface 2a, and the large end surface 3a is contacted and guided by the large flange surface 2c. Roll on top.
When the bearing is used, the small end surface 3b of the tapered roller 3 does not contact the small flange surface 2b of the inner race 2, and there is a slight gap between them.

FIG. 2 shows the raceway surface 1a of the outer race 1 and the inner race 2
2 schematically shows a contact state between the raceway surface 2a of the tapered roller 3 and the rolling surface 3c of the tapered roller 3. Crowning is shown quite exaggerated. The illustration of the retainer 4 is omitted. The dotted line exaggerates the shapes of the raceway surface and the rolling surface of the conventional bearing. The apex of the crowning of the raceway surface and the rolling surface in the conventional bearing is located at the axial center of each, and the center position of the contact portion between the rolling surface and the raceway surface is at the axial center position of the tapered roller.

In this embodiment, the raceway surface 1a, the raceway surface 2
By shifting the apex of the crowning of the a and the rolling surface 3c from the center in the axial direction toward the large diameter side, the raceway surface 1a
And contact part center position C between raceway surface 2a and rolling surface 3c
Is shifted by a predetermined amount α from the axial center of the tapered roller 3 (a position at a half of the length L) toward the large diameter side. Deviation amount α
Is 0 to 10% of the length (L) of tapered roller 3.
In this embodiment, α may be set within the following range.
= 5%. The length (L) is the small end face 3b.
And the contact position P of the large end surface 3a with the large flange surface 2c (dimension in the direction parallel to the axis of the tapered roller 3). The crowning amount (drop amount) is 1 to 6 μm for the rolling surface 3c, 1 to 20 μm for the raceway surface 1a,
The orbital surface 2a can be set arbitrarily in the range of 1 to 20 μm (in the case of composite crowning, 10 to 50 μm). With this configuration, the tapered roller 3 is smoothly moved in the axial direction toward the large flange surface 2c during the running-in operation, and the running-in time is reduced.

In the second embodiment shown in FIG. 3, the contact angle of the raceway surface 1a of the outer race 1 (the angle at which the extension of the raceway surface 1a intersects the center axis of the bearing: strictly speaking, the contact center position C of the raceway surface 1a
Is smaller than that of the conventional bearing (shown by a dotted line in the figure), and the contact angle of the raceway surface 2a of the inner race 2 is made smaller than that of the conventional bearing (shown by a dotted line in the figure). The center position C of the contact portion between the raceway surface 1a and the raceway surface 2a and the rolling surface 3c is shifted from the axial center of the tapered roller 3 (a position 1/2 of the length L) to the large diameter side. It is shifted by a predetermined amount α. Other items are the same as in the first embodiment.

In the first and second embodiments, the inner ring 2
Is turned so as to be substantially parallel to the small end face 3b of the tapered roller 3, and further subjected to grinding to finish the surface in parallel with the small end face 3b. The small flange surface of the inner ring in the conventional bearing is an inclined surface inclined outward with respect to the small end surface of the tapered roller. If the required accuracy can be secured,
In order to reduce costs, the small flange surface 2b may be turned into a surface parallel to the small end surface 3b by turning. Otsuba surface 2c
Can be finished by grinding while measuring the groove width dimension (W) from the small flange surface 2b with an in-process gauge using the small flange surface 2b as a dimension reference. Thereby, the groove width dimension (W) can be accurately finished within a predetermined dimensional tolerance with respect to the target dimension. The groove width dimension (W) is a dimension (a dimension in a direction parallel to the axis of the tapered roller 3) between the small flange surface 2b and the contact position P of the large flange surface 2c with the large end surface 3a.

In the first and second embodiments,
The groove width (W) of the inner ring 2 and the length (L) of the tapered roller 3 are finished within a predetermined dimensional tolerance, and the retainer 4, the plurality of tapered rollers 3, and the inner ring 2 are integrally assembled. By measuring the gap δ between the small end face 3b and the small flange face 2b when the large end face 3a of the tapered roller 3 is brought into contact with the large collar face 2c of the inner ring 2, the gap δ is set to δ ≦ 0. It is regulated to 4 mm. By making the small flange surface 2b of the inner ring 2 a surface parallel to the small end surface 3b of the tapered roller 3, it is possible to eliminate variations in the gap δ due to variations in the chamfer dimensions and shapes on the small end surface 3b side.

The tapered roller bearing according to the first and second embodiments is a bearing (bearings 23, 24, 27, 28, particularly a drive pinion shaft 22 rotatably supported) incorporated in a differential of an automobile as shown in FIG. Bearings 23, 2
Besides being suitable as 4), it is also suitable as a bearing incorporated in a gear device such as a transmission of an automobile.

[0026]

According to the present invention, the center position of the contact portion between the rolling surface of the tapered roller and the raceway surfaces of the inner and outer rings is shifted from the axial center of the tapered roller toward the large diameter side. The axial movement to the large end face side is promoted, so that the running-in operation time of this type of tapered roller bearing can be shortened, and at the same time, the reliability of the preload setting operation after the running-in operation can be improved. In addition, since the reference value of the size of the gap δ can be set large within an allowable range, it is advantageous in terms of reduction in processing cost and management cost.

The rotary shaft supporting structure for rotatably supporting the rotary shaft with respect to the casing by the tapered roller bearing as described above has a high preload setting work efficiency and a high reliability of the preload setting. , Especially as a support structure for a differential drive pinion shaft.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a tapered roller bearing according to an embodiment.

FIG. 2 is a cross-sectional view schematically showing a contact state between a raceway surface of an outer race and a raceway surface of an inner race, and a rolling surface of a tapered roller.

FIG. 3 is a cross-sectional view schematically showing a contact state between a raceway surface of an outer race and a raceway surface of an inner race and a rolling surface of a tapered roller.

FIG. 4 is a cross-sectional view showing an example of a configuration of a vehicle differential.

FIG. 5 is a diagram showing a relationship between a shift amount of a contact portion center position and the number of times the bearing is settled;

FIG. 6 is a sectional view showing a conventional tapered roller bearing.

FIG. 7 is a cross-sectional view (FIG. A) showing a state (initial state) of a conventional tapered roller bearing during assembly (FIG. A), a cross-sectional view showing a state after running-in (FIG. B), and a cross-sectional view showing a state during running-in. (FIG. C).

[Explanation of symbols]

 Reference Signs List 1 outer ring 1a raceway surface 2 inner ring 2a raceway surface 2b small flange surface 2c large flange surface 3 tapered roller 3a large end surface 3b small end surface C contact center position

Claims (5)

[Claims] 1. An outer race having a conical raceway surface provided with a crowning, a conical raceway surface provided with a crowning, a small flange surface on a small diameter side of the raceway surface and a large flange surface on a large diameter side. An inner ring having a flange surface, a plurality of tapered rollers having a conical rolling surface provided with a crowning, and being rotatably arranged between a raceway surface of an outer ring and a raceway surface of an inner ring; And a contact portion between the rolling surface of the tapered roller and the raceway surface of the inner / outer ring is displaced from the axial center of the tapered roller toward the large diameter side. A tapered roller bearing characterized by the following: 2. The tapered roller bearing according to claim 1, wherein the deviation amount α of the center position of the contact portion is within a range of 0 <α ≦ 0.1 L, where L is the length of the tapered roller. . 3. The tapered roller bearing according to claim 1, which is used for supporting a rotating shaft in a gear device of an automobile. 4. A support structure of a rotating shaft in a gear device of an automobile, wherein the rotating shaft incorporated in a casing is rotatably supported by a tapered roller bearing with respect to the casing, wherein the tapered roller bearing is provided with a crowning. An outer ring having a conical raceway surface provided, a conical raceway surface provided with a crowning, an inner ring having a small flange surface on a small diameter side of the raceway surface and a large flange surface on a large diameter side thereof, and crowning. And a plurality of tapered rollers which are rotatably arranged between the raceway surface of the outer ring and the raceway surface of the inner ring, and the tapered rollers are maintained at a predetermined circumferential distance. A gear for an automobile, comprising a retainer, wherein a center position of a contact portion between a rolling surface of the tapered roller and a raceway surface of an inner / outer ring is shifted from an axial center of the tapered roller to a large diameter side. Support structure of rotating shaft in equipment 5. A casing according to claim 1, wherein said casing is a differential case, and said rotary shaft is a drive pinion shaft having a front end connected to a propeller shaft and a rear end provided with a drive pinion gear meshing with a link gear. The support structure for a rotating shaft in a gear device for an automobile according to claim 4, characterized in that: