JP2012092855A - Rotation supporting device of pinion shaft - Google Patents

Abstract

The present invention realizes a structure that can achieve both reduction in rotational torque of a rolling bearing on the pinion gear side and securing of load capacity.
As a rolling bearing on the pinion gear 10a side, a single-row ball bearing 12 is used in place of a conventional single-row tapered roller bearing. Simultaneously, the inner ring raceway 15 constituting the ball bearing 12, by directly formed on the outer peripheral surface of the pinion shaft 3b, and the diameter D _A of the minimum diameter portion of the inner ring raceway 15, a single row tapered roller anti pinion gear side The diameter is smaller than the diameter D _B of the minimum diameter portion of the inner ring raceway 17 constituting the bearing 4d (D _A <D _B ). And the diameter d of each ball | bowl 16 and 16 which comprises the said ball bearing 12 is enlarged by that much. By adopting such a configuration, it is possible to achieve both reduction of the rotational torque of the rolling bearing and securing of the load capacity.
[Selection] Figure 1

Description

  The present invention relates to an improvement in a rotation support device for a pinion shaft that constitutes, for example, a differential device for an automobile and a transfer device for a four-wheel drive vehicle.

  A differential device for an automobile and a transfer device for a four-wheel drive vehicle usually include a pinion shaft provided with a pinion gear at one end, and a pair of pinion shafts provided inside the housing and separated in the axial direction. It has a structure that supports the axial load in both directions in a freely rotatable manner by a rolling bearing.

  FIG. 13 shows one described in Patent Document 1 as an example of a differential apparatus having such a structure. This differential device is provided in the middle of the power transmission system of an automobile to reduce the rotation of the propeller shaft and at the same time to change the rotation direction to a right angle. Is based on the traveling direction of the vehicle, and a pair of annular walls 2a and 2b are provided in the front-rear direction apart from each other in the “front” on the right and “rear” on the left. Inside these annular walls 2a, 2b, a pinion shaft 3 is supported by a pair of single row tapered roller bearings 4a, 4b so as to be rotatable and capable of supporting axial loads in both directions. These single-row tapered roller bearings 4a and 4b have a plurality of tapered rollers between outer rings 5a and 5b fitted inside the annular walls 2a and 2b and inner rings 6a and 6b fitted outside the pinion shaft 3, respectively. The rollers 7a and 7b are provided so as to roll freely. These single-row tapered roller bearings 4a and 4b are installed so that the contact angles are opposite to each other (providing a back-combined contact angle), thereby supporting both axial loads applied to the pinion shaft 3. It is possible.

  An annular body 8 is fixed to the front end portion of the pinion shaft 3. The coupling flange 9 constituting the front end portion of the annular body 8 is disposed at a portion protruding outward from the front end opening of the case 1. A rear end portion of a propeller shaft (not shown) can be connected to the coupling flange 9. A pinion gear 10 is fixed to the rear end portion of the pinion shaft 3, and the pinion gear 10 and the ring gear 11 are engaged with each other. The ring gear 11 is supported at the rear part inside the case 1 so as to be rotatable only.

  Next, FIG. 14 shows a part of the transfer device described in Patent Document 2. This transfer device is mounted on a four-wheel drive vehicle and distributes the output of the transmission to the front and rear wheels. A pinion shaft 3a is provided inside a case 1a, which is a housing, and a pair of single-row tapered roller bearings. By 4c and 4d, the axial load of both directions is supported rotatably. These single-row tapered roller bearings 4c, 4d have a plurality of tapered rollers 7c, 7d between outer rings 5c, 5d fitted in the case 1a and inner rings 6c, 6d fitted on the pinion shaft 3a. Is provided so that it can roll freely. These single-row tapered roller bearings 4c and 4d support the axial loads in both directions applied to the pinion shaft 3a by installing them with their contact angles opposite to each other (with a back combination type contact angle). It is possible.

  An annular body 8a is fixed to the rear end portion of the pinion shaft 3a. The coupling flange 9a constituting the rear end portion of the annular body 8a is disposed at a portion protruding outward from the rear end opening of the case 1a. A front end portion of a propeller shaft (not shown) can be connected to the coupling flange 9a. A pinion gear 10a is fixed to the front end portion of the pinion shaft 3a, and the pinion gear 10a and the ring gear 11a are engaged with each other. The ring gear 11a is supported on the inside of the case 1a so as to be rotatable only.

  By the way, in recent years, there has been a strong demand for saving fuel in automobiles, and power transmission loss is also associated with a pair of rolling bearings incorporated in a pinion shaft rotation support device that constitutes a differential device or a transfer device as described above. In order to keep the torque low, it is required to reduce the rotational torque. However, in the case of each of the conventional structures described above, it cannot be said that the rotational torque is sufficiently small.

  That is, in each of the conventional structures described above, single-row tapered roller bearings 4a and 4b (4c and 4d) are used as a pair of rolling bearings incorporated in the pinion shaft rotation support device. These single row tapered roller bearings 4a, 4b (4c, 4d) include outer rings 5a, 5b (5c, 5d) and inner rings 6a, 6b (6c, 6d) and tapered rollers 7a, 7b (7c, 7d). In addition to the rolling contact, the flanges 34 and 34 existing at the large-diameter end of the outer peripheral surface of the inner rings 6a and 6b (6c and 6d) and the heads of the tapered rollers 7a and 7b (7c and 7d) (large The diameter end face) is always in sliding contact with it, so the torque loss during rotation is large. In particular, the single-row tapered roller bearing 4a (4c) on the pinion gear 10 (10a) side has a larger axial load to be supported than the single-row tapered roller bearing 4b (4d) on the anti-pinion gear 10 (10a) side. The torque loss at that time is also larger than that of the single-row tapered roller bearing 4b (4d) on the anti-pinion gear 10 (10a) side.

  In this case, if a ball bearing is used instead of the single row tapered roller bearing 4a (4c) as the rolling bearing on the pinion gear 10 (10a) side, the rotational torque can be reduced. However, because the installation space is limited, the diameter of each ball (rolling element) constituting the ball bearing cannot be increased too much, and it is difficult to increase the number of each ball sufficiently. There is a concern that the load capacity of the rolling bearing on the pinion gear 10 (10a) side is reduced and the bearing life is reduced.

JP 11-48805 A Japanese Patent Laid-Open No. 10-220468

  In view of the circumstances as described above, the pinion shaft rotation support device of the present invention has been invented to realize a structure that can achieve both a reduction in rotational torque of the rolling bearing on the pinion gear side and securing of load capacity.

  Any of the pinion shaft rotation support devices of the present invention can be used to construct a differential device for an automobile or a transfer device for a four-wheel drive vehicle, and a pinion shaft provided with a pinion gear at one end is disposed inside the housing. A pair of rolling bearings provided apart from each other in the axial direction are rotatably supported and can support axial loads in both directions.

  In particular, in the rotation support device for a pinion shaft according to claim 1, an axial load in which the rolling bearing on the pinion gear side of the two rolling bearings acts on the pinion shaft from the pinion gear side toward the non-pinion gear side. A single row ball bearing (for example, a single row deep groove ball bearing or a single row angular ball bearing), and an inner ring raceway constituting the single row ball bearing is formed directly on the outer peripheral surface of the pinion shaft. The diameter of the minimum diameter portion of the inner ring raceway is smaller than the diameter of the minimum diameter portion of the inner ring raceway formed on the outer peripheral surface of the inner ring that is externally fitted and fixed to the pinion shaft constituting the anti-pinion gear side rolling bearing.

  In the rotation support device for a pinion shaft according to claim 2, the axial load in which the rolling bearing on the pinion gear side of the two rolling bearings acts on the pinion shaft from the pinion gear side toward the anti-pinion gear side. Tandem double row angular contact ball bearings that can support the pitch circle diameter (and raceway diameter) of the pinion gear side ball row is larger than the pitch circle diameter (and raceway diameter) of the anti-pinion gear side ball row, And double row angular contact ball bearings in which the contact angles of both rows are equal, and the double row inner ring raceway constituting the tandem type double row angular contact ball bearing is formed directly on the outer peripheral surface of the pinion shaft. Has been.

  In the rotation support device for a pinion shaft according to claim 3, the axial load in which the rolling bearing on the pinion gear side of the two rolling bearings acts on the pinion shaft from the pinion gear side toward the anti-pinion gear side. Is a single row tapered roller bearing, and an inner ring raceway constituting the single row tapered roller bearing is formed directly on the outer peripheral surface of the pinion shaft.

  Further, in the pinion shaft rotation support device according to claim 4, at least the inner ring raceway of the rolling bearing in the pinion shaft in which the inner ring raceway constituting the rolling bearing is formed directly on the outer peripheral surface of the pinion shaft. The part in which is formed is heat-treated by induction hardening.

  In the pinion shaft rotation support device according to claim 5, the outer ring constituting the rolling bearing also has a housing function, and is an integrated outer ring having a plurality of rows of raceways on the inner periphery. A flange for fixing the outer ring inside the housing is formed integrally with the outer ring on the outer periphery of the outer ring.

  In the pinion shaft rotary support device according to the sixth aspect, at least the raceway portion of the outer ring is heat-treated by induction hardening.

  In the case of the rotation support device for the pinion shaft of the present invention configured as described above, in the case of the one described in claim 1, instead of the conventional single row tapered roller bearing, a single row ball is used as the rolling bearing on the pinion gear side. Since a bearing is used, rotational torque can be reduced. In addition, this single row ball bearing has an inner ring raceway formed directly on the outer peripheral surface of the pinion shaft, and the diameter of the smallest diameter portion of the inner ring raceway is fixedly fitted to the pinion shaft constituting the rolling bearing on the anti-pinion gear side. Since the diameter of the inner ring raceway formed on the outer peripheral surface of the inner ring is smaller than the diameter of the minimum diameter portion, the diameter of each ball can be increased by that amount, and the load capacity can be increased. As a result, the life of the single row ball bearing can be brought close to that of a conventional single row tapered roller bearing. That is, according to the structure of the first aspect, the rotational torque of the pinion gear side rolling bearing is lower than that of the conventional single row tapered roller bearing while maintaining the same life as the conventional single row tapered roller bearing. Can be realized. Further, since the single row ball bearing used as the pinion gear side rolling bearing does not have an inner ring separate from the pinion shaft, the rotation support device can be easily assembled.

  In the case of adopting a structure in which the inner ring raceway is formed on the outer peripheral surface of a separate inner ring that is externally fitted and fixed to the pinion shaft as the single row deep groove ball bearing, the diameter of the minimum diameter portion of the inner ring raceway is reduced. In addition, the portion corresponding to the minimum diameter portion of the inner ring is thinned, resulting in a problem that it is difficult to ensure the strength (durability) of the portion. On the other hand, in the case of this example, since the structure in which the inner ring raceway of the single row deep groove ball bearing is directly formed on the outer peripheral surface of the pinion shaft is adopted, such a problem does not occur.

  In the case of the pinion shaft rotation support device according to claim 2, a tandem type double row angular contact ball bearing is used instead of the conventional single row tapered roller bearing as the pinion gear side rolling bearing. Therefore, rotational torque can be reduced. The tandem double-row angular contact ball bearing has a sufficiently large load capacity and a sufficiently long life compared to a single-row angular contact ball bearing of the same size. That is, according to the structure described in claim 2, it is possible to realize a rotational torque lower than that of a conventional single row tapered roller bearing while maintaining a sufficient life for the pinion gear side rolling bearing. Further, the tandem double-row angular contact ball bearing used as the pinion gear side rolling bearing does not have an inner ring separate from the pinion shaft, so that the rotation support device can be easily assembled.

  Further, in the case of the pinion shaft rotation support device according to claim 3, a single row tapered roller bearing is used as the pinion gear side rolling bearing, but the inner ring raceway surface is formed directly on the outer peripheral surface of the pinion shaft. Therefore, the device can be downsized while ensuring the load capacity. That is, according to the structure described in claim 3, the rolling bearing on the pinion gear side is smaller than the conventional single row tapered roller bearing while maintaining substantially the same life as the conventional single row tapered roller bearing. Can be realized. Further, since the single-row angular contact ball bearing used as the pinion gear side rolling bearing does not have an inner ring separate from the pinion shaft, the rotation support device can be easily assembled.

  Further, in the pinion shaft rotation support device according to claim 4, at least the inner ring raceway of the rolling bearing in the pinion shaft in which the inner ring raceway constituting the rolling bearing is formed directly on the outer peripheral surface of the pinion shaft. Since the part where the part is formed is heat-treated by quenching with high frequency, the required hardness as the raceway surface of the rolling bearing can be secured, and only the necessary part can be hardened, so the effect of heat treatment deformation etc. It can be prevented from reaching other parts of the shaft.

  In the rotation support device for a pinion shaft according to claim 5, the outer ring constituting the rolling bearing has a function of a housing, and is an integrated outer ring having a plurality of rows of raceways on the inner periphery. In addition, since the flange for fixing the outer ring is formed integrally with the outer ring on the outer periphery of the outer ring, it is possible to provide a flange for attachment to the housing on the outer ring outer periphery. Assembling of the rotation support device becomes easier.

  In the pinion shaft rotation support device according to claim 6, since at least the raceway portion of the outer ring is heat-treated by induction hardening, it is possible to ensure the necessary hardness as the raceway surface of the rolling bearing. In addition, since only a necessary portion can be cured, it is possible to prevent the influence of heat treatment deformation and the like from reaching other portions of the outer ring.

Sectional drawing which shows the 1st example of embodiment of this invention. Sectional drawing which shows the 2nd example. Sectional drawing which shows the 3rd example. Sectional drawing which shows the 4th example. Sectional drawing which shows the 5th example. Sectional drawing which shows the 6th example. The figure explaining the 1st example of the heat processing by the high frequency which concerns on this invention. The figure explaining the 2nd example of the heat processing by the high frequency which concerns on this invention. The figure explaining the 3rd example of the heat processing by the high frequency which concerns on this invention. The figure explaining the 4th example of the heat processing by the high frequency which concerns on this invention. The figure explaining the 1st example of the integrated outer ring | wheel which concerns on this invention. The figure explaining the 2nd example of the integrated outer ring | wheel which concerns on this invention. Sectional drawing which shows an example of the differential apparatus incorporating the rotation support apparatus of the conventional pinion shaft. The fragmentary sectional view which shows an example of the transfer apparatus incorporating the rotation support apparatus of the conventional pinion shaft.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention corresponding to claim 1. The feature of this example is the structure of the rolling bearing on the pinion gear 10a side (the right side in FIG. 1) among the pair of rolling bearings that support the pinion shaft 3b constituting the transfer device. Since the structure and operation of the other parts are almost the same as those of the conventional structure shown in FIG. 14 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The description will focus on the features of the example.

In the case of this example, of the pair of rolling bearings that support the pinion shaft 3b, the rolling bearing on the pinion gear 10a side is the pinion shaft 3b from the pinion gear 10a side to the anti-pinion gear 10a side (left side in FIG. 1). The single-row deep groove ball bearing 12 is capable of supporting an axial load acting on the. This single row deep groove ball bearing 12 is formed between a deep groove type outer ring raceway 14 formed on the inner peripheral surface of the outer ring 13 and a deep groove type inner ring raceway 15 formed directly on the front end portion of the outer peripheral surface of the pinion shaft 3b. In addition, a plurality of balls 16, 16 are provided so as to roll freely. Particularly, in the case of this example, by directly forming the inner ring raceway 15 in this manner on the outer peripheral surface of the pinion shaft 3b, and the diameter D _A of the minimum diameter portion of the inner ring raceway 15 (groove bottom), anti-pinion gear 10a minimum diameter portion of the inner ring raceway 17 constituting the single row tapered roller bearings 4d side in the example of {shown that smaller (D a _{<D B)} than the diameter D _B of the (smaller diameter end), the pinion shaft 3b, which is substantially equal to the diameter D _C of the outer ring fitted portion of the inner ring 6d constituting the single-row tapered roller bearing 4d on the side opposite to the pinion gear 10a (D _A ≈D _C )}. The amount of reduced diameter D _A of the minimum diameter portion only of the inner ring raceway 15 constituting the single-row deep groove ball bearing 12 in this manner, is to increase the diameter d of the respective balls 16, 16. The outer ring 13 of such a single row deep groove ball bearing 12 is fitted into the front end of the cylindrical member 18 constituting the case 1b. In this state, the outer ring 13 is positioned in the axial direction by abutting the rear end surface of the outer ring 13 against a step surface 19 formed on the inner peripheral surface of the cylindrical member 18.

  In the case of this example, the outer ring 5d of the single-row tapered roller bearing 4d on the side opposite to the pinion gear 10a is fitted in the portion near the rear end of the cylindrical member 18. Further, in this state, the outer ring 5d is positioned in the axial direction by abutting the front end face of the outer ring 5d against the step surface 20 formed on the inner peripheral surface of the cylindrical member 18. On the other hand, the inner ring 6d of the single row tapered roller bearing 4d is externally fitted to a portion near the rear end of the intermediate portion of the pinion shaft 3b. Further, in this state, a cylindrical spacer 22 in which the cross-sectional shape of the intermediate portion is an arch shape between the front end surface of the inner ring 6d and the stepped surface 21 formed at the intermediate portion of the outer peripheral surface of the pinion shaft 3b. , And the rear end face of the inner ring 6d is held down by an annular body 8a fitted and fixed to the rear end of the pinion shaft 3b. Thereby, the axial internal clearance between the single row deep groove ball bearing 12 and the single row tapered roller bearing 4d is adjusted, and the single row deep groove ball bearing 12 and the single row tapered roller bearing 4d are connected to the cylindrical member 18. Is prevented from falling off between the inner peripheral surface of the pinion shaft and the outer peripheral surface of the pinion shaft 3b.

In the case of the pinion shaft rotation support device of the present example configured as described above, instead of the conventional single row tapered roller bearing 4c (see FIG. 14), a single row deep groove ball bearing is used as the rolling bearing on the pinion gear 10a side. Since 12 is used, rotational torque can be reduced. In addition, the single row deep groove ball bearing 12 is formed by directly forming the inner ring raceway 15 on the outer peripheral surface of the pinion shaft 3b, thereby reducing the diameter D _A of the minimum diameter portion of the inner ring raceway 15 (D _A <D _B , D _A ≈D _C ), the diameter d of each ball 16, 16 is increased, so that the load capacity can be increased. Accordingly, the life of the single row deep groove ball bearing 12 can be made close to the life of the conventional single row tapered roller bearing 4c. That is, according to the structure of this example, the conventional single-row tapered roller bearing with the same life as the conventional single-row tapered roller bearing 4c (see FIG. 14) is maintained for the rolling bearing on the pinion gear 10a side. It becomes possible to realize a rotational torque lower than 4c. In the case of this example, since the single row deep groove ball bearing 12 used as the rolling bearing on the pinion gear 10a side does not have the inner ring separate from the pinion shaft 3b, the rotation support device can be easily assembled. Yes.

  If the inner ring raceway 15 is formed as the single row deep groove ball bearing 12 on the outer peripheral surface of a separate inner ring fitted and fixed to the pinion shaft 3b, the diameter of the minimum diameter portion of the inner ring raceway 15 is reduced. In this case, the portion corresponding to the minimum diameter portion of the inner ring is thinned, which causes a problem that it is difficult to ensure the strength (rolling fatigue life) of the portion. On the other hand, in the case of this example, since the structure in which the inner ring raceway 15 of the single row deep groove ball bearing 12 is directly formed on the outer peripheral surface of the pinion shaft 3b is adopted, such a problem may occur. There is no.

[Second Example of Embodiment]
FIG. 2 shows a second example of an embodiment of the present invention corresponding to claim 1. In this example, an axial load acting on the pinion shaft 3b can be supported from the anti-pinion gear 10a side to the pinion gear 10a side (right side in FIG. 2) as a rolling bearing on the anti-pinion gear 10a side (left side in FIG. 2). The tandem type double-row angular contact ball bearing 23 is used. The tandem double-row angular ball bearings 23 are formed on the inner peripheral surface of the outer ring 24, and are formed on the outer peripheral surface of the double-row outer ring raceways 25 a and 25 b each having an angular shape, and the inner ring 26. Between the double-row inner ring raceways 27a and 27b which are molds, a plurality of balls 28a and 28b are arranged for each row in a state where contact angles in the same direction are given to both rows, In addition, the pitch circle diameter of the ball row on the anti-pinion gear 10a side is set larger than the pitch circle diameter of the ball row on the pinion gear 10a side. In this example, a tandem double-row angular ball bearing 23 is used instead of the conventional single-row tapered roller bearing 4d (see FIG. 14) as the rolling bearing on the anti-pinion gear 10a side. Therefore, rotational torque can be reduced. Further, the diameter of the ball 28a on the side opposite to the pinion gear 10a and the diameter of the ball 28b on the side of the pinion gear 10a can be different. Other configurations and operations are the same as those of the first example described above.

[Third example of embodiment]
FIG. 3 shows a third example of the embodiment of the present invention corresponding to the first aspect. In the case of this example, the axial load acting on the pinion shaft 3b can be supported from the pinion gear 10a side (the right side in FIG. 3) to the anti-pinion gear 10a side (the left side in FIG. 3). The single-row angular contact ball bearing 29 is used. This single-row angular ball bearing 29 is formed between an angular outer ring raceway 14a formed on the inner peripheral surface of the outer ring 13a and an angular inner ring raceway 15a formed directly on the front end portion of the outer peripheral surface of the pinion shaft 3b. In addition, a plurality of balls 16, 16 are provided so as to roll freely with a contact angle applied. In the case of this example, a shoulder 30 is present on the rear end side of the outer ring raceway 14a on the inner peripheral surface of the outer ring 13a, but no shoulder is present on the front end side. For this reason, the single row angular contact ball bearing 29 can be easily assembled. Further, the number of balls 16 and 16 incorporated in the single row angular ball bearing 29 can be increased. That is, in the case of this example, the balls 16, 16 are held around the inner ring raceway 15a (by a retainer, grease, etc., not shown) and the balls 16, 16 are held on the outer ring raceway 14a. The single-row angular ball bearing 29 having a larger number of balls 16 and 16 can be easily assembled by inserting the inner ring in the axial direction from the front end side of the outer ring 13a. Other configurations and operations are the same as those in the above-described examples.

[Fourth Example of Embodiment]
FIG. 4 shows a fourth example of the embodiment of the present invention corresponding to the first aspect. In the case of this example, regarding the single row angular contact ball bearing 29a which is a rolling bearing on the pinion gear 10a side (right side in FIG. 4), the height H of the shoulder portion 30a existing at the rear end portion of the inner peripheral surface of the outer ring 13b is It is larger than 1/2 of the diameter d of the balls 16 and 16 (H> d / 2). In the case of this example, there is no shoulder portion on the side opposite to the pinion gear 10a (left side in FIG. 4) of the inner ring raceway 15a constituting the single row angular ball bearing 29a. Further, in the case of this example, the inner ring raceway 15a and the end surface of the pinion gear 10a are smoothly continued through the curved surface portion 31, thereby improving the strength and rigidity of the root portion of the pinion gear 10a. . Also in this example, the tandem double-row angular ball bearing 23 is used as the rolling bearing on the side opposite to the pinion gear 10a as in the case of the second example shown in FIG.

  In the case of the rotation support device for the pinion shaft of this example configured as described above, the outer ring 13b is fitted into the front end portion of the cylindrical member 18 in order to assemble the single row angular ball bearing 29a. With the balls 16, 16 disposed inside the outer ring raceway 14a formed on the inner peripheral surface, the operation of inserting the pinion shaft 3c inside the balls 16, 16 is performed using the front end portion of the cylindrical member 18 as shown in FIG. If it carries out in the state which faced upwards, it can prevent that each said balls 16 and 16 fall out from the inner side of the said outer ring track 14a with the said shoulder part 30a. For this reason, the assembly of the single row angular contact ball bearing 29a can be performed more easily. Note that the above-described spilling of the balls 16 and 16 can be prevented by a cage. However, in the case of the structure of this example, such a prevention function can be exhibited by the shoulder portion 30a. For this reason, what does not have this prevention function can be used as the said retainer, and the freedom degree of design can be raised by that much. Other configurations and operations are the same as those in the above-described examples.

[Fifth Example of Embodiment]
FIG. 5 shows a fifth example of the embodiment of the invention corresponding to claim 2. In the case of this example, an axial load acting on the pinion shaft 3b can be supported from the pinion gear 10a side to the non-pinion gear 10a side (left side in FIG. 5) as a rolling bearing on the pinion gear 10a side (right side in FIG. 5). The tandem type double-row angular contact ball bearing 23a is used. The tandem double-row angular ball bearings 23a are formed directly on the inner circumferential surface of the outer ring 24a, respectively on the outer circumferential surfaces of the outer circumferential surface of the pinion shaft 3b and the double-row outer ring raceways 25c and 25d each having an angular shape. A state in which a plurality of balls 28c and 28d are provided for each row and the contact angles in the same direction are given to each other between the formed inner ring raceways 27c and 27d each having an angular shape. And the pitch circle diameter of the ball row on the pinion gear 10a side is larger than the pitch circle diameter of the ball row on the anti-pinion gear 10a side. Also in this example, the tandem double-row angular ball bearing 23 is used as the rolling bearing on the side opposite to the pinion gear 10a as in the case of the second example shown in FIG. Further, the diameter of the ball 28c of the tandem double-row angular ball bearing 23a and the diameter of the ball 28d can be different.

  In the case of the rotation support device for the pinion shaft 3b of the present example configured as described above, a tandem type compound roller bearing 4c (see FIG. 14) is used as the rolling bearing on the pinion gear 10a side instead of the conventional single-row tapered roller bearing 4c. Since the row angular ball bearing 23a is used, the rotational torque can be reduced. The tandem double-row angular contact ball bearing 23a has a sufficiently large load capacity and a sufficiently long life compared to a single-row angular contact ball bearing of the same size. That is, according to the structure of this example, it is possible to realize a rotational torque lower than that of the conventional single row tapered roller bearing 4c while maintaining a sufficient life for the rolling bearing on the pinion gear 10a side. Further, since the tandem double-row angular ball bearing 23a used as the rolling bearing on the pinion gear 10a side does not have a separate inner ring, the rotation support device can be easily assembled. Other configurations and operations are the same as those in the above-described examples.

[Sixth Example of Embodiment]
FIG. 6 shows a sixth example of the embodiment of the present invention corresponding to the third aspect. In the case of this example, an axial load acting on the pinion shaft 3d can be supported from the pinion gear 10a side (right side in FIG. 6) to the anti-pinion gear 10a side (left side in FIG. 6). The single row tapered roller bearing 4e is used. This single-row tapered roller bearing 4e includes a conical concave outer ring raceway 32 formed on the inner peripheral surface of the outer ring 5c, and a conical convex inner ring raceway 33 formed directly on the front end portion of the outer peripheral surface of the pinion shaft 3d. A plurality of tapered rollers 7c, 7c are provided between them in a freely rollable manner.

  In the case of the rotation support device for the pinion shaft of this example configured as described above, a single-row tapered roller bearing is used as the rolling bearing on the pinion gear 10a side, but the inner ring raceway surface is the outer peripheral surface of the pinion shaft. Since it is directly molded, the device can be downsized. That is, according to the structure of this example, the conventional single row tapered roller retains substantially the same life as the conventional single row tapered roller bearing 4c (see FIG. 14) with respect to the rolling bearing on the pinion gear 10a side. It is possible to achieve a smaller size than the bearing. Further, since the single-row angular contact ball bearing 4e used as the rolling bearing on the pinion gear 10a side does not have a separate inner ring, the rotation support device can be easily assembled. Other configurations and operations are the same as those of the first example shown in FIG.

[Example of induction hardening]
FIG. 7 shows a modified example of the first embodiment shown in FIG. 1 and shows a state in which induction hardening is applied to the pinion shaft 103b in a form in which the pinion shaft 103b is a hollow shaft. In FIG. 7, the hardened layer 103c shown in dark color is quenched by high frequency and then tempered.

  As shown in FIG. 7, the induction hardening by high frequency and the subsequent tempering are preferably performed at least on the inner ring raceway 15 of the deep groove ball bearing formed directly on the pinion shaft 103b. Further, in the inner ring raceway 15, the surface hardness is hardened to HRC 58 to 64 by quenching by high frequency and subsequent tempering, and the effective hardened layer depth of this hardened layer is at least 2 mm. It is preferable to do. Further, when the pinion shaft 103b is a hollow shaft as in this embodiment, it is preferable that the radial thickness of the portion subjected to the hardening treatment by high frequency quenching is 4 mm or more. When the effective hardening depth is at least 2 mm, the rolling fatigue durability and load resistance of the inner ring raceway 15 are ensured. In addition, by setting the thickness in the radial direction of the portion subjected to the hardening treatment by induction hardening to 4 mm or more, the occurrence of quenching cracks or the like during the induction hardening treatment can be suppressed and cured to a uniform surface hardness. It becomes possible to further improve rolling fatigue durability and load resistance.

  Furthermore, when applying quenching by high frequency, the pinion shaft 103b is preferably formed of medium carbon steel containing 0.40 to 0.08 mass% of carbon. Specifically, carbon steel for machine structure of S38C to S58C defined by JIS, or the steel whose carbon concentration is further increased in S58C can be used. These steel materials have the required strength as a pinion shaft, and can be forged such as cold working and hot working, and have the necessary hardness by quenching by high frequency and the subsequent tempering described above. Moreover, since the price of the steel material itself is relatively low, it is suitable for obtaining the required performance at a low cost as a whole.

  A method of quenching by high frequency is not particularly limited, and a method generally applied to a shaft type can be applied without any problem. Also, for tempering performed after induction hardening, a method that is generally applied to a shaft configuration such as a method using high frequency can be applied without any problem.

  In the case of the pinion shaft 103b of the present embodiment, it is preferable to set the quenching temperature by high frequency to 820 to 920 ° C. and the tempering temperature to 140 to 240 ° C. in order to obtain the hardness of HRC 58 to 64. Further, as described above, it is preferable to appropriately change the quenching time, the tempering time, etc. in order to secure at least the effective curing depth of 2 mm or more.

  Here, it is preferable that the effective hardening depth of at least 2 mm is secured in a state where the inner ring raceway 15 is completed. In other words, normally, after the quenching by high frequency and the subsequent tempering process, the raceway surface is completed by grinding and superfinishing of the raceway surface. Will be removed. This is a so-called machining allowance and is usually 0.5 mm or less in thickness. However, taking into account this machining allowance, it is preferable to secure an effective curing depth of at least 2 mm.

  FIG. 8 shows an example of hardening processing by high-frequency quenching and subsequent tempering in the second embodiment shown in FIG. In the form shown in FIG. 8, not only the inner ring raceway 15 but also a plurality of stepped portions (portion where the shaft diameter changes) on the pinion shaft 203b and a fitting surface on which other parts are fitted to the pinion shaft 203b are induction-hardened. Subsequent tempering is performed. In FIG. 8, the hardened layer 203c shown in dark color is a portion that has been hardened.

  It is possible to improve the fatigue resistance when stress is concentrated on the stepped portion by quenching with high frequency on the stepped portion and then hardening by tempering, and the pinion shaft has high reliability. It can be. In addition, by performing high-frequency quenching on the mating surface on which other parts are mated, and subsequent hardening treatment by tempering, durability against stress and creep force due to interference on the mating surface is improved. In addition, since it is possible to finish the fitting surface with high accuracy by grinding or the like after the curing treatment, it is possible to improve the reliability of the whole fitting portion.

  Other preferable processing methods and effects in the form shown in FIG. 8 are the same as those shown in FIG.

  The form shown in FIG. 9 is the same as the third embodiment shown in FIG. 3 except that the entire outer periphery of the pinion shaft 303b including the tooth surface part and the step part of the pinion gear 10a is induction hardened and then hardened by tempering. The form which processed is shown. If necessary, the same processing may be applied to the end surface portion of the pinion shaft 303b. In FIG. 9, the hardened layer 303c shown in dark color is a portion that has been hardened.

  Similarly to the inner ring raceway 15a, the tooth surface portion of the pinion shaft 303b can be made to have a stronger tooth surface by being hardened by high frequency and then hardened by tempering. In addition, the entire process including the tooth surface portion and the step portion of the pinion shaft 303b can be processed at once, which is advantageous in terms of cost. In addition, induction hardening under different conditions and subsequent tempering can be performed on the tooth surface, track, step, and other outer peripheral parts, and a method other than induction hardening is applied to the tooth surface and step. Is also possible.

  Other preferable processing methods and effects in the form shown in FIG. 9 are the same as those shown in FIGS.

  The hardening treatment by induction hardening and subsequent tempering related to FIGS. 7 to 9 can be suitably applied to the fourth to sixth examples of the embodiment shown in FIGS. Moreover, it is also possible to apply combining the hardening process form shown to FIGS.

  FIG. 10 is a schematic view of a pinion shaft and a coupling flange portion in which the pinion shaft 403b and the inner ring raceway of the double-row angular ball bearing are integrated, and the coupling flange 9 and the inner ring raceway of the angular ball bearing are also integrated. FIG. In this embodiment, the pinion shaft 403b can be applied not only to the induction hardening related to FIGS.

  In FIG. 10, a dark-colored hardened layer 403c is a portion where quenching by high frequency and subsequent tempering are performed. However, a portion where quenching by high frequency and subsequent tempering are performed is not limited to the portion shown in FIG.

  Moreover, the example of the induction hardening shown in FIGS. 7-9, and also the hardening process by the induction hardening shown in FIGS. 7-10, and the subsequent tempering are the outer rings 13, 5d and case 1b shown in FIG. It is also possible to apply.

  FIG. 11 shows a first example of an integrated outer ring according to the present invention, and corresponds to a combination of an outer ring 500 formed integrally with a housing on the pinion shaft 403b shown in FIG. In this example, the outer ring 500 has two raceways 510 and 511 on the pinion gear side and one raceway 512 on the side opposite to the pinion gear, and is formed integrally. A flange 501 for attaching the outer ring to a casing (not shown) of the transfer device or the differential device is provided on the outer peripheral surface between the tracks 511 and 512 of the outer ring 500. The flange 501 is provided with a plurality of through-holes 502 through which mounting screws are penetrated substantially equally in the circumferential direction.

  In this way, the configuration in which the outer ring and the housing are integrated reduces the number of parts, leading to cost reduction, and facilitates assembly of the rotation support device and assembly of the rotation support device to the transfer device or differential device. Become.

  Here, the outer ring 500 is subjected to the same curing treatment as that shown in FIGS. 7 to 10 for the portions of the tracks 510, 511, and 512.

  FIG. 12 shows a second example of the integrated outer ring according to the present invention. Like the first example, the pinion shaft 403b shown in FIG. 10 is combined with an outer ring 500 formed integrally with the housing. Equivalent to.

  In the outer ring 500 of the second example, the base end portions 520 and 521 of the flange 501 are also subjected to hardening treatment by induction hardening and tempering. The strength of the flange base end is improved by applying a curing treatment to either the base end 520 or 521 or the base end 520 or 521 of the flange 501. Thereby, the reliability as a transfer apparatus or a differential apparatus can be improved.

  In each of the above-described embodiments, the present invention is applied to the pinion shaft rotation support device constituting the transfer device. However, the present invention is applied to the pinion shaft constituting the differential device as shown in FIG. It can also be applied to the rotation support device. Further, in the rolling bearing of the rotation support device, only the outer ring can be integrated, and the inner ring can be fitted as a separate body without being integrated with the pinion shaft.

DESCRIPTION OF SYMBOLS 1, 1a Case 2a-2d Annular wall 3, 3a-3d, 103b, 203b, 303b, 403b Pinion shaft 4a-4e Single row tapered roller bearing 5a-5d Outer ring 6a-6d Inner ring 7a-7d Tapered roller 8, 8a Ring body 9, 9a Coupling flange 10, 10a Pinion gear 11, 11a Ring gear 12 Single row deep groove ball bearing 13, 13a, 13b Outer ring 14, 14a Outer ring raceway 15, 15a Inner ring raceway 16 Ball 17 Inner ring raceway 18 Cylindrical member 19 Stepped surface 20 Stepped surface 21 Stepped surface 22 Spacer 23, 23a Double row angular contact ball bearing 24, 24a Outer ring 25a-25d Outer ring raceway 26 Inner ring 27a-27d Inner ring raceway 28a-28d Ball 29, 29a Single row angular contact ball bearing 30, 30a Shoulder part 31 Curved part 32 Outer ring raceway 33 inner ring raceway 34 buttock 103C, 03C, 303C, 403C cured layer 500 outer ring 501 the flange 510, 511, 512 orbit 520,521 proximal end

Claims (6)

  A pinion shaft having a pinion gear provided with a pinion gear at one end is rotatably supported by a pair of rolling bearings provided in the housing in the axial direction so as to be capable of supporting an axial load in both directions. In the rotary support device, the rolling bearing on the pinion gear side of the both rolling bearings is a single row ball bearing capable of supporting an axial load acting on the pinion shaft from the pinion gear side toward the anti-pinion gear side. The inner ring raceway constituting the single row ball bearing is directly formed on the outer peripheral surface of the pinion shaft, and the diameter of the minimum diameter portion of the inner ring raceway constitutes the anti-pinion gear side rolling bearing. A pinion shaft rotation support device, characterized in that it is smaller than the diameter of the smallest diameter portion of the inner ring raceway formed on the outer peripheral surface of the inner ring fitted and fixed to the outer ring.   A pinion shaft having a pinion gear provided with a pinion gear at one end is rotatably supported by a pair of rolling bearings provided in the housing in the axial direction so as to be capable of supporting an axial load in both directions. Of the two rolling bearings, the pinion gear side rolling bearing is capable of supporting an axial load acting on the pinion shaft from the pinion gear side toward the non-pinion gear side. A rotation support device for a pinion shaft, characterized in that a double-row inner ring raceway constituting a tandem type double-row angular ball bearing is formed directly on the outer peripheral surface of the pinion shaft.   A pinion shaft having a pinion gear provided with a pinion gear at one end is rotatably supported by a pair of rolling bearings provided in the housing in the axial direction so as to be capable of supporting an axial load in both directions. In the rotary support device, the rolling bearing on the pinion gear side of the two rolling bearings is a single row tapered roller bearing capable of supporting an axial load acting on the pinion shaft from the pinion gear side to the anti-pinion gear side. A rotation support device for a pinion shaft, wherein an inner ring raceway constituting the single row tapered roller bearing is formed directly on the outer peripheral surface of the pinion shaft.   The pinion shaft of the pinion shaft rotation support device according to any one of claims 1 to 3, wherein at least the orbital portion directly formed on the outer peripheral surface of the pinion shaft is heat-treated by induction hardening. Rotation support device for pinion shaft.   The housing and the outer ring are integrally formed, and the outer ring is an integrated outer ring having a plurality of rows of tracks on the inner periphery, and a flange for fixing the outer ring is integrated with the outer ring on the outer periphery of the outer ring. The rotation support device according to claim 1, wherein the rotation support device is formed.   6. The rotary support device according to claim 5, wherein at least a raceway portion of the outer ring is heat-treated by induction hardening.

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