JP2017141855A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide novel means for suppressing a change of a power transmission state resulting from thermal expansion/contraction accompanied by a temperature change of a differential carrier.SOLUTION: A differential device 1 comprises: a ring gear 18 fixed to a differential gear mechanism 31; a drive pinion shaft 13 having a pinion gear 14 which is geared with the ring gear 18 at a distal end part; a rear bearing 16 (distal bearing) for supporting at least the vicinity of the pinion gear 14 of the drive pinion shaft 13; and a differential carrier 21 for supporting the differential gear mechanism 13 and an outer race 42 of the rear bearing 16. The outer race 42 comprises an engagement piece 45 having an engagement face 45a at a distal side rather than a proximal end part 42b of the outer race 42 being the engagement piece 45 which extends to the outside of the outer race 42 in a radial direction. The engagement face 45a is engaged with a shoulder part 21a arranged at the differential carrier 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a differential gear mechanism, a drive pinion shaft, and a differential device including a differential carrier that houses and supports them.

  In a differential device including a differential gear mechanism, a drive pinion shaft, and a differential carrier that accommodates and supports them, a dimensional change accompanying a temperature change, that is, a thermal expansion and contraction can be a problem. For example, if the positional relationship between the ring gear fixed to the differential gear mechanism and the pinion gear provided on the drive pinion shaft changes due to the thermal expansion and contraction of the differential carrier, noise and vibration are likely to occur in these gears. There is a possibility that the power transmission state fluctuates.

  In Patent Document 1, the differential carrier is composed of a plurality of structures having different linear expansion coefficients. According to this configuration, the thermal expansion and contraction of the differential carrier is suppressed by the structure having a lower linear expansion coefficient than the case where all the differential carrier structures have a high linear expansion coefficient.

JP 2007-071306 A

  An object of the present invention is to provide a novel means for suppressing a dimensional change accompanying a temperature change in a differential carrier, that is, a change in a power transmission state caused by thermal expansion and contraction.

In order to achieve the above object, a differential according to the present invention includes:
A ring gear fixed to the differential gear mechanism;
A drive pinion shaft having a pinion gear meshing with the ring gear at the distal end;
A distal bearing that supports at least the vicinity of the pinion gear of the drive pinion shaft;
A differential carrier that supports the differential gear mechanism and the outer race of the distal bearing;
A differential device comprising:
The outer race includes an engagement piece that extends outward in the radial direction of the outer race, and has an engagement piece that has an engagement surface distal to the proximal end of the outer race. The mating surface engages with a shoulder provided on the differential carrier.

  According to the present invention, when the engagement piece of the outer race of the distal bearing is engaged with the shoulder provided on the differential carrier, the engagement piece is engaged more distally than the proximal end of the outer race. A differential carrier between the support point that supports the differential gear mechanism and the support point that supports the outer race as compared to the configuration that engages the differential carrier at the proximal end portion of the outer race because it has a mating surface. The dimension of becomes smaller. For this reason, according to this invention, the dimensional change accompanying the temperature change in a differential carrier can be suppressed, Therefore, the change of the power transmission state resulting from thermal expansion and contraction can be suppressed.

1 is a cross-sectional plan view of a differential device according to a first embodiment of the present invention. It is a principal part enlarged view which shows the rear bearing in 1st Embodiment, and its periphery. It is a perspective view which shows the outer race in 1st Embodiment. It is a principal part enlarged view which shows the unit bearing in 2nd Embodiment, and its periphery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional plan view of a vehicle differential device according to a first embodiment of the present invention. The differential device 1 of the present embodiment is for driving rear wheels in a FR (front engine / rear drive) vehicle, for example. In FIG. 1, the direction indicated by “front” of the arrow is the front side of the vehicle. In this specification, the direction close to the drive source in the power transmission path is referred to as “proximal”, and the direction far from the drive source is referred to as “distal”. In the differential device 1 according to this embodiment, the front of the vehicle The side is “proximal”.

  As shown in FIG. 1, the differential device 1 includes a differential housing 20, a drive pinion shaft 13, a drive pinion gear 14, a front bearing 15, a rear bearing 16, a ring gear 18, a differential gear mechanism 31, and the like.

  The differential housing 20 includes a differential carrier 21 and a carrier cover 22. Both the differential carrier 21 and the carrier cover 22 are made of an aluminum-based material. The carrier cover 22 is fastened by a bolt 25 to the opening at the rear end of the differential carrier 21.

  A pinion shaft chamber 23 is formed in the front portion (front side of the vehicle) of the differential carrier 21, and a front bearing 15 and a rear bearing 16 that are rolling bearings are fitted in the pinion shaft chamber 23. ing. The drive pinion shaft 13 is rotatably supported by the front bearing 15 and the rear bearing 16. The rear bearing 16 supports the vicinity of the drive pinion gear 14 of the drive pinion shaft 13 and corresponds to a distal bearing in the present invention. In this embodiment, angular ball bearings (single row, double row) are used for the front bearing 15 and the rear bearing 16 for the purpose of reducing the loss. However, the bearing is, for example, a cone generally used in a differential device. It may be a roller bearing.

  The rear bearing 16 includes an inner race 41, an outer race 42, and two rows of balls 43 that roll between them, and the balls 43 are held by a cage 44 made of resin.

  A flange 6 is fastened by a nut 5 to one end (front side of the vehicle) of the drive pinion shaft 13. An oil seal 17 is provided between the flange 6 and the front bearing 15. The flange 6 is connected by a bolt (not shown) to the rearmost end of a propeller shaft (not shown) that transmits the power of an engine (not shown) that is a drive source provided at the front of the vehicle. The drive source may be a motor.

  A drive pinion gear 14 is integrally formed at the distal end of the drive pinion shaft 13, that is, the shaft end opposite to the flange 6, and the drive pinion gear 14 meshes with the ring gear 18. Depending on the gear ratio between the drive pinion gear 14 and the ring gear 18, the rotational driving force of the drive pinion shaft 13 is decelerated, and the driving force after the deceleration is transmitted to the ring gear 18. The drive pinion gear 14 and the ring gear 18 are configured using bevel gears or a kind of hypoid gear. When the hypoid gear is used, the axial direction of the ring gear 18 is different from the axial direction of the drive pinion shaft 13 and is a twisted position that is orthogonal in a plan view.

  The ring gear 18 is housed together with the differential gear mechanism 31 in a differential mechanism chamber 24 formed in the rear portion (rear side of the vehicle) inside the differential carrier 21. The differential gear mechanism 31 includes a differential case 33, side gears 34 and 35, differential pinions 36 and 37, a differential pinion shaft 38, and the like. The ring gear 18 is fixed to the differential case 33 by bolts 32, so that the ring gear 18 can rotate integrally with the differential case 33.

  In the hollow portion of the differential case 33, a differential pinion shaft 38 is held in a direction orthogonal to the axis A, which is the central axis when the differential case 33 rotates. Are rotatably supported in directions facing each other. A pair of side gears 34 and 35 disposed on the left and right sides of the hollow portion of the differential case 33 are meshed with the differential pinions 36 and 37 with the differential pinion shaft 38 as a boundary. The side gears 34 and 35 are connected to one end of left and right axles (not shown) inserted through the differential case 33 so as to be integrally rotatable, and the other ends of the left and right axles are connected to left and right wheels (not shown). Is connected.

  In the differential device 1 configured as described above, the driving force of the engine (not shown) is changed by a transmission (not shown), and the driving force after the transmission is transmitted to the drive pinion shaft 13 through a propeller shaft (not shown). Is done. When the drive pinion gear 14 of the drive pinion shaft 13 rotates, the ring gear 18 meshed with the drive pinion gear 14 and the differential case 33 to which the ring gear 18 is fixed are rotationally driven. By rotation of the differential case 33, the side gears 34, 35 of the hollow portion, the differential pinions 36, 37, the differential pinion shaft 38 and the left and right axles (not shown) inserted through the differential case 33 are integrally rotated. The left and right wheels (not shown) are driven to rotate differentially by the rotation of the axle.

  Now, as described above, the differential carrier 21 constituting the differential housing 20 is made of an aluminum-based material. On the other hand, the remaining main members of the differential device 1, particularly the drive pinion shaft 13, the drive pinion gear 14, the front bearing 15, the rear bearing 16, the ring gear 18 and the differential gear mechanism 31, are all made of iron. . Since the linear expansion coefficient of the aluminum-based material is significantly larger than that of iron, in the differential device 1, a dimensional change accompanying a temperature change, that is, a thermal expansion and contraction can be a problem. For example, if the positional relationship between the ring gear 18 fixed to the differential gear mechanism 31 and the drive pinion gear 14 provided on the drive pinion shaft 13 changes due to thermal expansion and contraction of the differential carrier 21, noise is generated in these gears. There is a risk that the power transmission state may fluctuate, such as a tendency to generate noise (such as a roaring sound) or vibration.

  Therefore, the differential device 1 according to the first embodiment provides a novel means for suppressing a dimensional change accompanying a temperature change in the differential carrier 21, that is, a change in the power transmission state caused by thermal expansion and contraction. Yes. That is, the outer race 42 of the rear bearing 16, which is a distal bearing in the present invention, includes an engagement piece 45 extending radially outward of the outer race 42, and the engagement piece 45 is connected to the differential carrier 21. Is engaged.

  As shown in FIG. 2, the engagement piece 45 is provided at the distal end portion 42 a of the outer race 42. The engagement piece 45 has an engagement surface 45a facing in the proximal direction. On the other hand, the differential carrier 21 has a shoulder portion 21a, and the engagement piece 45 is restricted from moving in the proximal direction by engaging with the shoulder portion 21a. The proximal end portion 42b of the outer race 42 is not in contact with the second shoulder portion 21b of the differential carrier 21 facing in the proximal direction, and after the outer race 42 is assembled, there is a gap g between the two. Is formed.

  As shown in FIG. 3, the engagement piece 45 is provided over the entire circumference of the outer race 42, so that the shape of the engagement piece 45 is a hook shape as a whole. Correspondingly, the shoulder 21 a of the differential carrier 21 is also provided in an annular shape over the entire circumference surrounding the outer race 42. Since the engagement piece 45 has a hook shape, the rigidity thereof can be increased. However, the engagement piece 45 and the shoulder portion 21a may be provided only in a part of the periphery of the outer race 42, or a plurality of tab-like engagement pieces may be provided.

  In the differential device 1 of the first embodiment configured as described above, the engagement piece 45 of the outer race 42 of the rear bearing 16 (distal bearing) engages with the shoulder portion 21 a provided on the differential carrier 21. However, since the engagement piece 45 has the engagement surface 45a facing the proximal direction on the distal side of the proximal end portion 42b (see FIG. 2) of the outer race 42, the proximal end portion of the outer race 42 is provided. Compared with the configuration in which the differential carrier 21 is engaged in 42 b, the support point for supporting the differential gear mechanism 31 (for example, the axis A of the left and right axles (not shown) inserted through the differential case 33), and the outer race 42. The size of the differential carrier 21 between the support points for supporting the carrier becomes small. Specifically, in the dimension L1 between the axis A and the engagement surface 45a of the engagement piece 45 and the dimension L2 between the axis A and the proximal end portion 42b of the outer race 42, the former is more preferable. Small (L1 <L2). Generally, the amount of thermal expansion of a member is determined by the linear expansion coefficient × dimension × temperature difference. According to this embodiment, the support point (axis A) for supporting the differential gear mechanism 31 and the support for supporting the outer race 42 are provided. Since the dimension between the point (engagement surface 45a) can be made smaller, the dimensional change accompanying the temperature change in the differential carrier 21 can be suppressed, and therefore the change in the power transmission state due to the thermal expansion and contraction can be suppressed. .

  Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the vicinity of the distal end portion of the drive pinion shaft 13 is supported by the rear bearing 16, and the vicinity of the proximal end portion of the drive pinion shaft 13 is separated from the rear bearing 16. It is supported by a certain front bearing 15. However, since the differential expansion coefficient of the differential carrier 21 made of an aluminum-based material is higher than that of other main members made of iron, particularly the drive pinion shaft 13, in the region between the rear bearing 16 and the front bearing 15 when the temperature rises. The effect of thermal expansion of the differential carrier 21 becomes significant, and the axial preload applied between the rear bearing 16 and the front bearing 15 in the assembling process is reduced, which may cause abnormal noise and reduced durability. . Therefore, in the second embodiment, a unit for holding both the vicinity of the distal end portion and the vicinity of the proximal end portion of the drive pinion shaft 113 in place of the rear bearing 16 and the front bearing 15 in the first embodiment described above. A bearing 116 is used.

  In FIG. 4, in the differential gear according to the second embodiment, a pinion shaft chamber 123 is formed inside the front portion (front side of the vehicle) of the differential carrier 121, and the pinion shaft chamber 123 is a rolling bearing. A unit bearing 116 is accommodated. The unit bearing 116 includes inner races 141a and 141b, a single member outer race 142, and two rows of balls 143 that roll between them, and the balls 143 are held by a resin cage 144. ing. Further, the unit bearing 116 includes a row of balls 146 in the vicinity of the end on the proximal side (that is, the right side in FIG. 4). As a result of adopting such a configuration, in the unit bearing 116, the vicinity of the distal end portion of the drive pinion shaft 113 by the distal ball 143, and the vicinity of the proximal end portion of the drive pinion shaft 113 by the ball 146. , Each of which is rotatably supported. The unit bearing 116 has a function of supporting the vicinity of the proximal end portion of the drive pinion shaft 113, but still supports the vicinity of the pinion gear 114 of the drive pinion shaft 113, and corresponds to a distal bearing in the present invention. The outer race 142 has a through hole 142c for lubrication. The unit bearing 116 may be a tapered roller bearing.

  The outer race 142 of the unit bearing 116 includes an engagement piece 145 extending outward in the radial direction of the outer race 142. The engagement piece 145 is provided at the distal end 142 a of the outer race 142. The engagement piece 145 has an engagement surface 145a facing in the proximal direction. On the other hand, the differential carrier 121 has a shoulder 121a, and the engagement piece 145 is restricted from moving in the proximal direction by engaging with the shoulder 121a. The proximal end 142b of the outer race 142 is not in contact with the second shoulder 121b of the differential carrier 121 facing in the proximal direction, and after the outer race 142 is assembled, there is a gap g between the two. Is formed. The engagement piece 145 is provided over the entire circumference of the outer race 142. Correspondingly, the shoulder 121 a of the differential carrier 121 is also provided in an annular shape over the entire circumference surrounding the outer race 42. However, the engagement piece 145 and the shoulder 121a may be provided only in a part of the periphery of the outer race 142, or a plurality of tab-like engagement pieces may be provided.

  The engagement piece 145 is provided with at least one through hole 145b, and the outer race 142 is fixed to the differential carrier 121 by a bolt 147 through the through hole 145b.

  In the differential device according to the second embodiment configured as described above, the engagement piece 145 provided on the outer race 142 engages with the shoulder 121 a provided on the differential carrier 121. Therefore, as in the first embodiment, the dimension between the support point (axis A) for supporting the differential gear mechanism 31 and the support point (engagement surface 145a) for supporting the outer race 142 can be further reduced. The dimensional change accompanying the temperature change in the differential carrier 121 can be suppressed, and the change in the power transmission state due to the thermal expansion and contraction can be suppressed.

  In the second embodiment, the unit bearing 116 for holding both the distal end portion and the proximal end portion of the drive pinion shaft 113 is used, and in particular, near and near the distal end portion of the drive pinion shaft 113. The vicinity of the end portion is held by an outer race 142 which is a single member. Therefore, even though the linear expansion coefficient of the differential carrier 121 made of an aluminum-based material is higher than that of other main members made of iron, particularly the drive pinion shaft 113, when the temperature rises, the distal end portion of the drive pinion shaft 113 The influence of the thermal expansion of the differential carrier 121 in the region between the proximal end portions on the distance between the holding points of the balls 143 and 146 can be suppressed. Therefore, in the second embodiment, it is possible to suppress the reduction of the axial preload, the abnormal noise, and the deterioration of the durability that are applied between the rear bearing 16 and the front bearing 15 in the assembly process.

  In each of the above embodiments, the engagement pieces 45 and 145 are provided at the distal ends of the outer races 42 and 142 of the distal bearing, but the engagement pieces in the present invention are provided on the proximal side of the outer race. The configuration is not limited to the above as long as it has an engagement surface distal to the end. In each of the above embodiments, an example of a differential device for a rear wheel has been shown. However, the differential device of this embodiment can also be applied to a differential device for a front wheel. The materials of the differential carrier and other members are not limited to those described above, and other light non-ferrous metals such as a magnesium-based material may be used for the differential carrier, for example. The differential carrier may be composed of a plurality of structures having different linear expansion coefficients.

  The present invention is not limited to the above-described aspects and modifications, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Differential device 13,113 Drive pinion shaft 14,114 Drive pinion gear 15 Front bearing 16 Rear bearing 18 Ring gear 20 Differential housing 21, 121 Differential carrier 21a, 121a Shoulder 31 Differential gear mechanism 42, 142 Outer race 45, 145 Engagement Joint piece 45a, 145a engagement surface

Claims (1)

A ring gear fixed to the differential gear mechanism;
A drive pinion shaft having a pinion gear meshing with the ring gear at the distal end;
A distal bearing that supports at least the vicinity of the pinion gear of the drive pinion shaft;
A differential carrier that supports the differential gear mechanism and the outer race of the distal bearing;
A differential device comprising:
The outer race includes an engagement piece that extends outward in the radial direction of the outer race, and has an engagement piece that has an engagement surface distal to the proximal end of the outer race. The mating surface engages with a shoulder provided on the differential carrier.

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