JP6171444B2 - Rolling bearing device and pinion shaft support device for vehicle - Google Patents

Description

  The present invention relates to a vehicle pinion shaft support device for supporting a pinion shaft used in a rolling bearing device, a differential gear device, and the like.

  In a differential gear device or the like used for a vehicle such as an automobile, a tapered roller bearing may be used as a rolling bearing for supporting a pinion shaft (see, for example, Patent Document 1).

JP 2006-283791 A

In the tapered roller bearing, the tapered roller and the raceway surface of the race are in line contact. Therefore, the contact area between the tapered roller and the raceway surface in the tapered roller bearing is relatively larger than that of, for example, a ball bearing. For this reason, the tapered roller bearing can keep the contact surface pressure relatively small in a high load load region, which is advantageous for reducing the rotational torque of the bearing.
On the other hand, in the low load load region, in addition to the relatively large contact area between the tapered roller and the raceway surface, the tapered roller and the flange that holds the tapered roller in the axial direction are in sliding contact. The influence of sliding friction resistance increases, and for example, the rotational torque of the bearing tends to increase as compared with a ball bearing or the like.

Therefore, it is conceivable to use a ball bearing instead of the tapered roller bearing. Ball bearings have a point contact between the ball and the raceway surface in the low load load region, so the contact area between the ball and raceway surface can be reduced compared to the tapered roller bearing. Since there is no configuration corresponding to the flange portion of the tapered roller bearing, the rotational torque of the bearing can be reduced.
However, in the high load load region, the contact surface pressure becomes very high, and the resulting high frictional resistance increases the rotational torque of the bearing.

  As described above, even if either a tapered roller bearing or a ball bearing is adopted, there is a load load region that relatively increases the rotational torque of the bearing, so that it rotates in a wide load load region. There has been a problem that torque cannot be reduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a rolling bearing device and a vehicle pinion shaft support device capable of reducing the rotational torque in a wide load range.

The present invention is a rolling bearing device including an outer ring fitted on the inner circumferential surface of the housing and an inner ring fitted on the outer circumferential surface of the shaft member, and is a plurality of bearings arranged in the circumferential direction. Tapered roller bearings having tapered rollers, and a plurality of balls arranged in the axial direction on the tapered roller bearings and arranged in the circumferential direction with a pitch circle diameter different from the pitch circle diameter of the plurality of tapered rollers. A ball bearing portion provided, and the outer ring is composed of a first outer ring portion included in the ball bearing portion formed integrally with each other and a second outer ring portion included in the tapered roller bearing portion, the inner ring is composed of a second inner ring contained in the tapered roller bearing unit and the first inner ring part that is included in the ball bearing portion formed integrally with each other, before Kigairin or greater radial than a predetermined load to the inner ring The first outer ring when a load is applied It is but clearance for reducing the ratio of load of radial load borne by the ball bearing unit and allowed to elastically deform radially outwardly, and the outer peripheral surface of the first outer portion, the inner periphery of the housing It is characterized by being formed between the surfaces .

According to the rolling bearing device having the above-described configuration, when a radial load larger than a predetermined load is applied to the outer ring or the inner ring, the first outer ring portion is elastically deformed, so that the radial load acting on the ball bearing portion is appropriately released. It is possible to suppress a radial load larger than a predetermined load from acting on the ball bearing portion.
Thus, when a radial load larger than a predetermined load is applied to the outer ring or the inner ring, the ball bearing portion bears compared to a case where a radial load smaller than the predetermined load is applied to the outer ring or the inner ring. The load ratio of radial load can be reduced and the load ratio of radial load borne by the tapered roller bearing portion can be increased.

In other words, in the low load load region where the radial load acting on the outer ring or inner ring is smaller than the predetermined load, the load is generally applied to the ball bearing portion that is advantageous for reducing rotational torque in the low load load region, and the load acts on the outer ring or inner ring. In a high load load region where the radial load to be applied is larger than a predetermined load, the load can be applied to a tapered roller bearing portion that is generally advantageous in reducing the rotational torque in the high load load region.
As described above, according to this configuration, it is possible to vary the bearing portion that mainly bears the load in the low load load region and the high load load region, and as a result, it is possible to reduce the rotational torque in a wide load load region. Can do.

Further, the present invention is a rolling bearing device including an outer ring fitted on the inner circumferential surface of the housing and an inner ring fitted on the outer circumferential surface of the shaft member, which are arranged in the circumferential direction. A tapered roller bearing portion having a plurality of tapered rollers, and a plurality of tapered roller bearing portions arranged in the axial direction in the tapered roller bearing portion and arranged in the circumferential direction with a pitch circle diameter different from a pitch circle diameter of the plurality of tapered rollers. A ball bearing portion including a ball, and the outer ring includes a first outer ring portion included in the ball bearing portion and a second outer ring portion included in the tapered roller bearing portion that are integrally formed with each other. the inner ring is composed of a second inner ring contained in the tapered roller bearing unit and the first inner ring part that is included in the ball bearing portion formed integrally with each other, than the predetermined load before Kigairin or the inner ring When a large radial load is applied, Clearance for reducing the ratio of load of radial load inner ring is borne by the ball bearing unit and allowed to elastically deform toward the inside in the radial direction, the inner peripheral surface of the first inner ring portion, said shaft It is characterized by being formed between the outer peripheral surface of the part .

  Also in this case, when a radial load larger than a predetermined load is applied to the outer ring or the inner ring, the first outer ring portion is elastically deformed, so that the radial load acting on the ball bearing portion can be appropriately released, and the predetermined load or more. Can be prevented from acting on the ball bearing portion. As a result, it is possible to vary the bearing portion that mainly bears the load in the low load load region and the high load load region, and it is possible to reduce the rotational torque in a wide load load region.

  Moreover, it is preferable that the said clearance gap is formed because the surrounding surfaces which form the said clearance gap make clearance fit, and a clearance gap can be formed easily in this case.

In the rolling bearing device, it is preferable that a preload for the ball bearing portion is set larger than a preload for the tapered roller bearing portion.
In this case, the ball bearing portion can be more effectively loaded with the load in the low load load region.

Further, the present invention is a vehicle pinion shaft support device including a rolling bearing device that rotatably supports a pinion shaft having a pinion gear meshing with a differential mechanism at one end, wherein the rolling bearing device includes the above-described rolling bearing device. It is a rolling bearing device.
According to the above configuration, as described above, it is possible to reduce the rotational torque in a wide load range.

  According to the rolling bearing device and the vehicle pinion shaft support device of the present invention, it is possible to reduce the rotational torque in a wide load range.

It is sectional drawing of the differential gear apparatus provided with the rolling bearing apparatus which concerns on the 1st Embodiment of this invention. It is an expanded sectional view of the rolling bearing 7 on the head side. It is sectional drawing of the rolling bearing apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the rolling bearing apparatus which concerns on the 3rd Embodiment of this invention. It is a fragmentary sectional view of the rolling bearing device which shows the modification of 1st Embodiment.

  Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a differential gear device including a rolling bearing according to a first embodiment of the present invention. The differential gear device 1 is used in a drive mechanism of a vehicle such as an automobile, and includes a pinion shaft 3 that is rotationally driven by a drive shaft (not shown) and a differential reduction mechanism 5 in a housing 2. .

A pinion gear 4 is provided at the tip of the pinion shaft 3. The pinion gear 4 meshes with the ring gear 6 of the differential reduction mechanism 5.
The differential speed reduction mechanism 5 to which the rotational force of the drive shaft is transmitted via the pinion shaft 3 transmits the rotational force to the left and right drive wheels while performing differential operation of the left and right drive wheels (not shown).

A support portion 2 a having a circular inner periphery is formed inside the housing 2 as a part of the housing 2. The pinion gear 4 side (hereinafter also referred to as the head side) of the pinion shaft 3 is rotatably supported with respect to the support portion 2a by a rolling bearing 7 attached to the support portion 2a.
The opposite side (hereinafter also referred to as tail side) of the pinion shaft 3 is rotatably supported with respect to the housing 2 by a rolling bearing 8 attached to a cylindrical portion 2b formed at the end of the housing 2. Yes.
In other words, the rolling bearings 7 and 8 constitute a vehicle pinion shaft support device that rotatably supports the pinion shaft 3 having the pinion gear 4 meshing with the differential reduction mechanism 5 formed at one end.

The tail-side rolling bearing 8 forms a so-called tandem double-row ball bearing, and includes an inner ring 81 attached to the pinion shaft 3, an outer ring 82 attached to the cylindrical portion 2b of the housing 2, and an inner and outer rings. Are provided with a plurality of balls 83 provided in double rows in the axial direction, and cages 84 in each row. A cylindrical spacer 9 is mounted on the pinion shaft 3 between the bearings 7 and 8. The inner ring 81 of the rolling bearing 8 is sandwiched between the spacer 9 and the annular shielding plate 10 in the axial direction. The shielding plate 10 is pressed by a flange 11 attached to the other end side of the pinion shaft 3 so as to be integrally rotatable with the pinion shaft 3 by spline fitting. The flange 11 is fixed by a bolt 14 that is screwed into a thread portion formed at the tip of the pinion shaft 3.
An oil seal 12 is mounted between the flange 11 and the housing 2, and the oil seal 12 is covered with a protective cap 13 attached to the flange 11.

  The head-side rolling bearing 7 also constitutes a tandem type double-row rolling bearing. The head-side rolling bearing 7 will be described in detail later.

  Here, the lubricating operation of the differential gear device 1 will be described. Lubricating oil (not shown) for lubricating the entire interior of the differential gear device 1 is stored at the bottom of the housing 2. In addition, the support portion 2a forms a lubricating oil supply path P in the housing 2 for introducing lubricating oil to lubricate the rolling bearings 7 and 8 as indicated by arrows in the figure.

  The ring gear 6 of the differential reduction mechanism 5 is rotationally driven in the direction indicated by the arrow in the drawing when the vehicle is in the forward drive state, and is stored at the bottom of the housing 2 by the rotation of the ring gear 6. Bounce the lubricant upward. The splashed lubricating oil passes through the lubricating oil supply path P, is guided between the pair of rolling bearings 7 and 8, and is supplied to the bearing. The lubricating oil that has passed through the head-side rolling bearing 7 is returned to the bottom of the housing 2. Further, the lubricating oil that has passed through the tail-side rolling bearing 8 passes through a reflux path (not shown) and is returned to the bottom of the housing 2. In this way, the lubricating oil circulates inside the differential gear device 1.

FIG. 2 is an enlarged sectional view of the rolling bearing 7 on the head side.
In the figure, the head-side rolling bearing 7 includes an inner ring 20 mounted on the pinion shaft 3, an outer ring 21 mounted on the support portion 2 a, and a plurality of rolling rings arranged in double rows between the inner ring 20 and the outer ring 21. A ball 22 and a tapered roller 23 as a moving body, and a pair of cages 24 and 25 holding the ball 22 and the tapered roller 23 in the circumferential direction are provided.

The outer ring 21 is an annular member formed of bearing steel, machine structural alloy steel, or the like, and a first outer ring raceway 21a and a second outer ring raceway 21b are formed side by side in the axial direction on the inner peripheral surface. .
The inner ring 20 is an annular member formed of bearing steel, machine structural alloy steel, or the like, and is disposed concentrically with the outer ring 21. On the outer peripheral surface of the inner ring 20, a first inner ring raceway 20a facing the first outer ring raceway 21a and a second inner ring raceway 20b facing the second outer ring raceway 21b are formed.

A plurality of balls 22 are arranged between the first outer ring raceway 21a and the first inner ring raceway 20a that are formed on one end side in the axial direction and face each other. A plurality of tapered rollers 23 are disposed between the second outer ring raceway 21b and the second inner ring raceway 20b that are formed on the other end side in the axial direction and face each other.
The plurality of balls 22 and the plurality of tapered rollers 23 are held at equal intervals in the circumferential direction by retainers 24 and 25, respectively. The cages 24 and 25 are annular members formed of metal, resin, or the like, and are arranged in an annular space between the inner and outer rings 20 and 21 to hold the balls 22 and the tapered rollers 23.

The plurality of balls 22 are members formed using bearing steel or the like, and are interposed between the first inner ring raceway 20a and the first outer ring raceway 21a so as to be freely rollable.
The ball 22 is in contact with the first inner ring raceway 20a and the first outer ring raceway 21a at a predetermined inclination angle with respect to the radial direction by shifting the contact point on the first inner ring raceway 20a side to one end side in the axial direction. Therefore, the ball 22 and the inner and outer rings 20 and 21 constitute an angular ball bearing.

The plurality of tapered rollers 23 are members formed using bearing steel or the like, and are interposed between the second inner ring raceway 20b and the second outer ring raceway 21b so as to roll freely.
The tapered roller 23 is disposed such that the small diameter end surface 23a is on the other end side in the axial direction and the large diameter end surface 23b is on the one end side in the axial direction, and the small roller portion 26 and the large flange portion 27 formed on the inner ring 20 It is held in the axial direction. Therefore, the tapered roller 23 and the inner and outer rings 20, 21 constitute a tapered roller bearing in which one end side in the axial direction is the large diameter end side of the inner ring 20.

As described above, in the rolling bearing 7 on the head side according to the present embodiment, the balls 22 are arranged in one of the rolling elements arranged in multiple rows, and the cones are arranged in the other row. Rollers 23 are arranged to constitute a tandem type double-row rolling bearing in which a tapered roller bearing and a ball bearing are combined.
That is, the rolling bearing 7 includes a tapered roller bearing portion 60 that constitutes a tapered roller bearing, and a ball bearing portion 70 that is arranged in the axial direction on the tapered roller bearing portion 60 and constitutes a ball bearing. .

A ball bearing portion 70 provided on one end side in the axial direction of the rolling bearing 7 includes a first outer ring portion 71 on one end side in the axial direction of the outer ring 21, a first inner ring portion 72 on one end side in the axial direction of the inner ring 20, and a plurality of It includes a ball 22.
Further, the tapered roller bearing portion 60 provided on the other axial end side of the rolling bearing 7 includes a second outer ring portion 61 on the other axial end side of the outer ring 21 and a second inner ring on the other axial end side of the inner ring 20. The unit 62 is configured to include a plurality of tapered rollers 23.
Therefore, the outer ring 21 includes a first outer ring portion 71 included in the ball bearing portion 70 and a second outer ring portion 61 included in the tapered roller bearing portion 60 that are integrally formed with each other. The inner ring 20 includes a first inner ring portion 72 included in the ball bearing portion 70 and a second inner ring portion 62 included in the tapered roller bearing portion 60 that are integrally formed with each other.

In a tapered roller bearing, generally, the large collar part and the small collar part hold the tapered roller in the axial direction while being in sliding contact with both end faces of the tapered roller. Therefore, a slight clearance is given to the axial distance between the large collar part and the small collar part with respect to the axial length of the tapered roller.
On the other hand, in the ball bearing, there is almost no clearance in the axial direction between the ball and the raceway, so that the relative movement of the inner ring and the outer ring can be restricted.

  Therefore, according to the rolling bearing 7 of the present embodiment, the first outer ring portion 71 and the first inner ring portion 72 of the ball bearing portion 70 are restricted from relatively moving in the axial direction by the balls 22 interposed therebetween. Therefore, the ball bearing portion 70 can regulate the relative movement of the outer ring 21 and the inner ring 20 in the axial direction. For this reason, it can suppress that an error arises in the positional relationship of the 2nd outer ring part 61 and the 2nd inner ring part 62 contained in tapered roller bearing part 60 in the direction of an axis. As a result, it is possible to suppress the two flange portions 26 and 27 that hold the tapered roller 23 included in the tapered roller bearing portion 60 in the axial direction from sliding on the axial end surface of the tapered roller 23 with a high surface pressure. The occurrence of galling in the collar portions 26 and 27 can be suppressed.

In the first outer ring raceway 21a and the first inner ring raceway 20a, the pitch circle diameter of the plurality of balls 22 arranged in a row along the circumferential direction is larger than the pitch circle diameter of the tapered rollers 23 also arranged in a row. It is formed to be large. Therefore, the annular space formed between the inner ring 20 and the outer ring 21 is formed so as to gradually increase in diameter from the other axial end side toward the one axial end side.
For this reason, the rolling bearing 7 in the operating state introduces lubricating oil into the bearing from the annular opening between the inner and outer rings 20 and 21 on the other end side in the axial direction by the centrifugal force of the inner ring 20 and the annular ring on the one end side. A pumping action is produced that drains from the opening.

  Lubricating oil passes through the inside of the bearing by the pump action. Therefore, the intermediate portion 28 between the large collar portion 27 and the first inner ring raceway 20a is connected by a smooth curved surface. As a result, the lubricating oil passing through the inside of the bearing can easily flow, and the lubricating oil can be quickly discharged to the outside of the bearing.

  Further, an annular portion 25 a extending radially inward is formed at the other axial end of the cage 25. A circumferential groove 29 that is recessed inward in the radial direction is formed on the shoulder on the other end side of the inner ring 20. The annular portion 25 a is inserted inside the circumferential groove 29 so that a slight gap is formed between the inner surface of the circumferential groove 29. As a result, the substantial opening area in the annular opening on the other axial end side can be reduced, and the lubricating oil introduced into the bearing from the annular opening on the other axial end side by the pumping action. The amount can be limited.

  That is, when the amount of lubricating oil introduced into the bearing from the annular opening between the inner and outer rings 20 and 21 on the other axial end side is relatively large, the rotational torque of the rolling bearing 7 is increased by the stirring resistance of the lubricating oil. There is a risk of causing. For this reason, the stirring resistance of the lubricating oil can be reduced by limiting the amount of the lubricating oil introduced into the bearing by the annular portion 25a and the circumferential groove 29. As a result, the rotational torque of the rolling bearing 7 can be reduced.

Further, the large-diameter end surface 20 c of the inner ring 20 is in contact with the side surface 4 a of the pinion gear 4. The inner ring 81 of the tail-side rolling bearing 8 is fixed by a flange 11 attached to the end of the pinion shaft 3 (see FIG. 1).
The outer ring 82 of the tail-side rolling bearing 8 and the outer ring 21 of the head-side rolling bearing 7 are fixed in the axial direction by the cylindrical portion 2b and the support portion 2a.
Therefore, if the bolt 14 is tightened and the flange 11 is pressed toward the head side, the inner rings 20 and 81 of both bearings 7 and 8 can be pressed so as to approach each other along the axial direction. The preload for the bearings 7 and 8 can be adjusted. In addition, when adjusting the preload of both the bearings 7 and 8, the axial direction length of the spacer 9 is also adjusted.

Here, on the outer peripheral surface side of the outer ring 21 of the rolling bearing 7 of the present embodiment, there are a large-diameter outer peripheral surface 40, a small-diameter outer peripheral surface 41, and a step surface 42 connecting the large-diameter outer peripheral surface 40 and the small-diameter outer peripheral surface 41. Is formed.
Further, on the inner peripheral surface side of the support portion 2a on which the outer ring 21 is mounted, a large-diameter inner peripheral surface 50, a small-diameter inner peripheral surface 51, and a large-diameter inner A step surface 52 that connects the peripheral surface 50 and the small-diameter inner peripheral surface 51 is formed.

  The step surface 42 and the other axial end surface 43 of the outer ring 21 are in contact with the step surface 52 of the support portion 2a and the annular wall 53 formed radially inward from the end portion of the small-diameter inner peripheral surface 51. . As a result, the outer ring 21 is positioned in the axial direction.

  The large-diameter outer peripheral surface 40 is formed from one end edge of the outer peripheral surface of the outer ring 21 to a position overlapping the large-diameter end surface 23b of the axial tapered roller 23. The small-diameter outer peripheral surface 41 is formed from the other end edge of the large-diameter outer peripheral surface 40 to the other end edge of the outer peripheral surface of the outer ring 21 through the step surface 52.

  That is, the large-diameter outer peripheral surface 40 constitutes the outer peripheral surface of the first outer ring portion 71 included in the ball bearing portion 70, and the small-diameter outer peripheral surface 41 is the second outer ring portion 61 included in the tapered roller bearing portion 60. An outer peripheral surface is formed.

The small-diameter outer peripheral surface 41 is fitted and fixed to the small-diameter inner peripheral surface 51 of the support portion 2a by interference fit, whereby the outer ring 21 is fixed to the support portion 2a.
On the other hand, the large-diameter outer peripheral surface 40 is a clearance fit with respect to the large-diameter inner peripheral surface 50 of the support portion 2a.
The outer diameter dimension of the large-diameter outer peripheral surface 40 is set to a fitting dimension in which a gap of about 10 to 20 μm is formed with respect to the large-diameter inner peripheral surface 50 of the support portion 2a.
Thus, the small-diameter outer peripheral surface 41 is fitted and fixed, while the large-diameter outer peripheral surface 40 forms a clearance S with respect to the large-diameter inner peripheral surface 50. In FIG. 2, the gap S is exaggerated for easy understanding. The gap S is set to about 10 to 20 μm as described above.

Here, the first outer ring portion 71 included in the ball bearing portion 70 is formed to be elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20. In addition, since the above-described gap S is formed between the large-diameter outer peripheral surface 40 and the large-diameter inner peripheral surface 50, the first outer ring portion 71 is allowed to elastically deform toward the radially outer side. ing.
That is, in the present embodiment, the first outer ring portion 71 is elastic when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20 between the large-diameter outer peripheral surface 40 and the large-diameter inner peripheral surface 50. A gap S that allows deformation is formed.

Therefore, according to the rolling bearing 7 of the present embodiment, the first outer ring portion 71 is elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20, and therefore acts on the ball bearing portion 70. A radial load can be released moderately, and a radial load larger than a predetermined load can be prevented from acting on the ball bearing portion 70.
Thereby, when the radial load larger than the predetermined load is acting on the outer ring 21 or the inner ring 20, the ball bearing portion is compared with the case where the radial load smaller than the predetermined load is acting on the outer ring 21 or the inner ring 20. The load ratio of the radial load which 70 bears can be decreased, and the load ratio of the radial load which the tapered roller bearing part 60 bears can be increased.

For this reason, in the low load load region where the radial load acting on the outer ring 21 or the inner ring 20 is smaller than the predetermined load, the load is mainly borne on the ball bearing portion 70, and the radial load acting on the outer ring 21 or the inner ring 20 is the predetermined load. In a larger high load load region, the tapered roller bearing portion 60 can be loaded with a load.
In the low load load region, the ball bearing generally has a smaller friction torque than the tapered roller bearing, and the rotational torque can be relatively lowered. On the other hand, in the high load load region, conversely, the tapered roller bearing can make the rotational torque relatively lower than the ball bearing.
Therefore, according to this configuration, it is possible to vary the bearing portion that mainly bears the load in the low load load region and the high load load region, and as a result, it is possible to reduce the rotational torque in a wide load load region. .

  Moreover, according to the rolling bearing 7 of this embodiment, in a high load load area | region, since a load is mainly borne by the highly tapered tapered roller bearing part 60, lifetime improvement can be achieved.

  In addition, as a predetermined load which can elastically deform the 1st outer ring | wheel part 71, it can be set to 1500 MPa which is a fatigue limit load of the ball | bowl used for a bearing. Thereby, it is possible to suppress a radial load larger than the fatigue limit load of the ball from acting on the ball 22.

  In the present embodiment, the clearance S necessary to allow the first outer ring portion 71 to elastically deform by making the large-diameter outer peripheral surface 40 a clearance fit with respect to the large-diameter inner peripheral surface 50. Therefore, the gap S can be easily formed.

Moreover, the rolling bearing 7 of this embodiment is set so that the preload applied to the ball bearing portion 70 and the preload applied to the tapered roller bearing portion 60 are different.
More specifically, the preload for the ball bearing portion 70 is set larger than the preload for the tapered roller bearing portion 60. Thereby, in the low load load region, by reducing the preload on the tapered roller bearing portion 60 relatively, the radial load borne by the tapered roller bearing portion 60 is reduced, and the radial load is effectively applied to the ball bearing portion 70. Can be borne. As a result, the rotational torque in the low load load region can be more effectively reduced.

FIG. 3 is a cross-sectional view of a rolling bearing according to the second embodiment of the present invention.
In the present embodiment, a large-diameter inner peripheral surface 45 and a small-diameter inner peripheral surface 46 are formed on the inner ring 20, and the large-diameter outer peripheral surface 40 and the small-diameter outer peripheral surface 41 of the outer ring 21 are formed with respect to the support portion 2 a. It is different from the first embodiment in that it is fitted and fixed by interference fit. About another point, it is the structure similar to 1st Embodiment.

  In the present embodiment, the large-diameter inner peripheral surface 45 of the inner ring 20 is formed from one end edge of the inner peripheral surface of the inner ring 20 to the vicinity of the other end where the axial ball 22 is present. The small diameter inner peripheral surface 46 of the inner ring 20 is formed from the other end edge of the large diameter inner peripheral surface 45 to the other end edge of the inner peripheral surface of the inner ring 20 via the step surface 47.

  That is, the large-diameter inner peripheral surface 45 constitutes the inner peripheral surface of the first inner ring portion 72 included in the ball bearing portion 70, and the small-diameter inner peripheral surface 46 is the second inner ring included in the tapered roller bearing portion 60. The inner peripheral surface of the portion 62 is configured.

The small diameter inner peripheral surface 46 of the inner ring 20 is fitted and fixed to the outer peripheral surface 56 of the pinion shaft 3 by interference fit. Thereby, the inner ring 20 is fixed to the pinion shaft 3.
On the other hand, the large-diameter inner peripheral surface 45 is formed to be separated from the outer peripheral surface 56 of the pinion shaft 3 in the radial direction, thereby forming an annular gap S with respect to the outer peripheral surface 56.

The first inner ring portion 72 included in the ball bearing portion 70 is formed to be elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20. Further, since the annular gap S is formed between the large-diameter inner peripheral surface 45 and the outer peripheral surface 56, the first inner ring portion 72 is allowed to elastically deform toward the radially inner side. .
That is, in the present embodiment, the first inner ring portion 72 is elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20 between the large-diameter inner circumferential surface 45 and the outer circumferential surface 56. A gap S that allows this is formed.

Thereby, according to the rolling bearing 7 of this embodiment, when the radial load larger than a predetermined load acts on the outer ring 21 or the inner ring 20, the first inner ring portion 72 is elastically deformed, so that it acts on the ball bearing portion 70. The radial load to be released can be released moderately, and the radial load larger than the predetermined load can be prevented from acting on the ball bearing portion 70.
As a result, also in the present embodiment, as in the first embodiment, it is possible to vary the bearing portions that mainly bear the load in the low load load region and the high load load region, and the rotational torque can be varied in a wide load load region. Reduction can be achieved.

FIG. 4 is a sectional view of a rolling bearing according to the third embodiment of the present invention.
The rolling bearing 7 of this embodiment is different from that of the first embodiment in that the tapered roller bearing portion 60 is provided on one end side in the axial direction and the ball bearing portion 70 is provided on the other end side in the axial direction. .

In the present embodiment, the small-diameter outer peripheral surface 41 of the outer ring 21 constitutes the outer peripheral surface of the first outer ring portion 71 included in the ball bearing portion 70, and the large-diameter outer peripheral surface 40 of the outer ring 21 is included in the tapered roller bearing portion 60. The outer peripheral surface of the second outer ring portion 61 is configured.
The large-diameter outer peripheral surface 40 is fitted and fixed to the support portion 2a by an interference fit. The small-diameter outer peripheral surface 41 is a loose fit with respect to the support portion 2a.

In this embodiment, the outer diameter dimension of the small-diameter outer peripheral surface 41 is set to a fitting dimension in which a gap S of about 10 to 20 μm is formed with respect to the small-diameter inner peripheral surface 51 of the support portion 2a.
Thereby, the small-diameter outer peripheral surface 41 forms a slight gap S with respect to the small-diameter inner peripheral surface 51. In FIG. 4, the gap S is exaggerated for easy understanding.

Similar to the first embodiment, the first outer ring portion 71 is formed to be elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21. In addition, since the gap S is formed between the small-diameter outer peripheral surface 41 and the small-diameter inner peripheral surface 51, the first outer ring portion 71 is allowed to elastically deform toward the radially outer side.
That is, in the present embodiment, the first outer ring portion 71 is elastically deformed when a radial load larger than a predetermined load is applied to the outer ring 21 or the inner ring 20 between the small-diameter outer peripheral surface 41 and the small-diameter inner peripheral surface 51. A gap S that allows this is formed.

  As a result, also in the present embodiment, as in the first embodiment, it is possible to vary the bearing portions that mainly bear the load in the low load load region and the high load load region, and the rotational torque can be varied in a wide load load region. Reduction can be achieved.

  The present invention is not limited to the above embodiment. For example, in each of the above embodiments, the large-diameter outer peripheral surface 40 of the outer ring 21 and the large-diameter inner peripheral surface 45 of the inner ring 20 that form a clearance S between the support portion 2a and the pinion shaft 3 are cylindrical. If the clearance S allowing the elastic deformation of the first outer ring portion 71 or the first inner ring portion 72 can be formed between the support portion 2a and the pinion shaft 3, the cylindrical surface shape can be formed. There is no need to be a taper surface, a curved surface, or a combination of these.

  In the first embodiment, a circumferential groove 29 that is recessed radially inward is formed in the shoulder on the other end side of the inner ring 20, and the annular portion 25 a of the retainer 25 is inserted inside the circumferential groove 29. Thus, the configuration for limiting the amount of lubricating oil introduced into the bearing has been shown. For example, as shown in FIG. 5, instead of the circumferential groove 29, a slight gap is formed between the annular portion 25a. A step 30 may be provided. Also in this case, the amount of lubricating oil introduced into the bearing can be limited as in the case of the circumferential groove 29.

3 Pinion shaft 4 Pinion gear 5 Differential reduction mechanism 7 Rolling bearing (rolling bearing device) 20 Inner ring 20a First inner ring raceway 20b Second inner ring raceway 21 Outer ring 21a First outer ring raceway 21b Second outer ring raceway 22 Ball 23 Tapered roller 40 Large diameter Outer peripheral surface 41 Small-diameter outer peripheral surface 45 Large-diameter inner peripheral surface 46 Small-diameter inner peripheral surface 50 Large-diameter inner peripheral surface 51 Small-diameter inner peripheral surface 56 Outer peripheral surface 60 Tapered roller bearing portion 61 Second outer ring portion 62 Second inner ring portion 70 Ball bearing portion 71 1st outer ring part 72 1st inner ring part

Claims (5)

A rolling bearing device comprising: an outer ring fitted on the inner circumferential surface of the housing; and an inner ring fitted on the outer circumferential surface of the shaft member,
A tapered roller bearing having a plurality of tapered rollers arranged in the circumferential direction;
A ball bearing portion provided with a plurality of balls arranged in a circumferential direction with a pitch circle diameter different from a pitch circle diameter of the plurality of tapered rollers provided in an axial direction in the tapered roller bearing portion; and
The outer ring is composed of a first outer ring part included in the ball bearing part integrally formed with each other and a second outer ring part included in the tapered roller bearing part,
The inner ring is composed of a first inner ring part included in the ball bearing part and a second inner ring part included in the tapered roller bearing part, which are integrally formed with each other,
Burden before Kigairin or radial load the ball bearing unit and allowed to elastically deform to bear toward the first outer portion is radially outward when a large radial load than a predetermined load to the inner ring is applied A rolling bearing device , wherein a gap for reducing the ratio is formed between the outer peripheral surface of the first outer ring portion and the inner peripheral surface of the housing . A rolling bearing device comprising: an outer ring fitted on the inner circumferential surface of the housing; and an inner ring fitted on the outer circumferential surface of the shaft member,
A tapered roller bearing having a plurality of tapered rollers arranged in the circumferential direction;
A ball bearing portion provided with a plurality of balls arranged in a circumferential direction with a pitch circle diameter different from a pitch circle diameter of the plurality of tapered rollers provided in an axial direction in the tapered roller bearing portion; and
The outer ring is composed of a first outer ring part included in the ball bearing part integrally formed with each other and a second outer ring part included in the tapered roller bearing part,
The inner ring is composed of a first inner ring part included in the ball bearing part and a second inner ring part included in the tapered roller bearing part, which are integrally formed with each other,
Burden before Kigairin or radial load the ball bearing unit and allowed to elastically deform to bear toward the first inner ring portion radially inward when a radial load is applied greater than a predetermined load to the inner ring A rolling bearing device , wherein a gap for reducing the ratio is formed between an inner peripheral surface of the first inner ring portion and an outer peripheral surface of the shaft portion .   The rolling bearing device according to claim 1, wherein the gap is formed by a clearance fit between peripheral surfaces forming the gap.   The rolling bearing device according to claim 1, wherein a preload for the ball bearing portion is set larger than a preload for the tapered roller bearing portion. A pinion shaft support device for a vehicle including a rolling bearing device that rotatably supports a pinion shaft formed at one end of a pinion gear meshing with a differential mechanism,
The said rolling bearing apparatus is a rolling bearing apparatus as described in any one of Claims 1-4, The pinion shaft support apparatus for vehicles characterized by the above-mentioned.

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