CN214036759U - Differential gear - Google Patents

Abstract

The utility model provides a differential mechanism. The differential case (C) has a first side wall portion (Cs1) and a first bearing boss (Cb1) and a second side wall portion (Cs2) and a second bearing boss (Cb 2). The ring gear (8) is fixed so as to be offset toward the first bearing boss (Cb1) side, and receives a radial load. The side wall portions and the bearing boss are connected to each other via first and second corner portions (R1, R2), respectively. The first corner (R1) is formed into a first curved surface (R1) of an arc shape. The second corner (R2) is formed into an arc-shaped second curved surface (R2) that is recessed inward in the axial direction and inward in the radial direction. The radius of curvature of the second curved surface (r2) is larger than that of the first curved surface (r 1).

Description

Differential gear

Technical Field

The utility model relates to a differential mechanism, especially the differential mechanism that the ring gear is fixed by the skew in the axial of differential mechanism case.

Background

Such a differential is known as disclosed in japanese patent No. 5802958.

In the differential disclosed in the above publication, since the ring gear meshes with the drive gear, a radial load in a direction orthogonal to the rotation axis acts on the differential case by a meshing reaction force thereof. The radial load acts strongly on the bearing boss on the side closer to the ring gear in the axial direction. Therefore, a large shearing force acts on the periphery of the corner between the bearing boss and the side wall portion of the differential case.

However, since the recess portion recessed inward in the axial direction is formed at the corner portion, it is likely to become a starting point of stress concentration, and the strength of the differential case may be reduced.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a differential mechanism that can solve above-mentioned problem.

In order to achieve the above object, the present invention has: a differential case supported by the transmission case via a first bearing and a second bearing; and a differential gear mechanism housed in the differential case and distributing an input torque input to the differential case to a first output shaft and a second output shaft, wherein the differential case includes: a first side wall portion on one side in the axial direction; a second side wall portion on the other side in the axial direction; a first bearing boss connected to the first side wall portion and extending axially outward; and a second bearing boss connected to the second sidewall portion and extending axially outward; a ring gear that meshes with the drive gear is fixed to the differential case so as to be offset in the axial direction toward the first bearing boss side, an outer side surface of the first side wall portion and an outer peripheral surface of the first bearing boss are connected via a first corner portion, and an outer side surface of the second side wall portion and an outer peripheral surface of the second bearing boss are connected via a second corner portion, the first corner portion is formed as an arc-shaped first curved surface which is not recessed more inward in the axial direction than an outer side surface of the first side wall portion, and is not recessed radially inward with respect to the outer peripheral surface of the first bearing boss, the second corner portion is formed as an arcuate second curved surface recessed axially inward with respect to the outer side surface of the second side wall portion, and is recessed more radially inward than the outer peripheral surface of the second bearing boss, and the radius of curvature of the second curved surface is larger than the radius of curvature of the first curved surface.

Since the ring gear is fixed to the transmission so as to be offset toward the first bearing boss side in the axial direction, a shearing force acts strongly on the first corner portion closer to the ring gear due to a radial load applied to the ring gear. On the other hand, the bending moment acts strongly on the second corner portion farther from the ring gear.

In contrast, the first corner portion is formed as an arc-shaped first curved surface that is not recessed inward in the axial direction and inward in the radial direction. Therefore, the sectional area of the peripheral portion of the first corner portion can be secured to a large extent, and the strength against shear force is improved. On the other hand, the second corner portion is formed as an arc-shaped second curved surface recessed inward in the axial direction and inward in the radial direction. Therefore, the stress concentration to the second corner portion caused by the bending moment is effectively suppressed.

In the present invention, "the axial direction of the differential case" means the direction along the rotation axis of the differential case. The "radial direction of the differential case" means a radial direction of an arc centered on the rotation axis. The "cross section of the first and second corners" means a cross section that includes the rotation axis of the differential case and that intersects the first and second corners.

Drawings

Fig. 1 is a longitudinal sectional view of a differential according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view and an enlarged view of a main portion of a differential case and a bearing of the differential only

Description of the reference symbols

B1, B2 are a first bearing and a second bearing;

c, a differential case;

cb1, Cb2 first and second bearing bosses;

cs1, Cs2, first and second side wall portions;

d, a differential mechanism;

fb1, fb2 the outer peripheral surfaces of the first and second bearing bosses;

fs1 and fs2 outer side surfaces of the first and second side wall portions;

r1, R2, first and second corners;

r1 and r2 are first and second curved surfaces;

8, a gear ring;

9, driving a gear;

10, a gear box;

20, a differential gear mechanism.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

As shown in fig. 1, a differential D for distributing power from a power source to first and second output shafts 11, 12 is housed in a transmission 10 of an automobile. The first and second output shafts 11, 12 are connected to left and right driving wheels, respectively.

The differential D has a differential case C and a differential gear mechanism 20 housed in the differential case C. The differential case C is supported by the transmission case 10 by first and second bearings B1, B2 so as to be rotatable about the first axis X1.

The differential case C integrally has a first side wall portion Cs1 on one axial side, a second side wall portion Cs2 on the other axial side, a first bearing boss Cb1 connected to the first side wall portion Cs1 and extending axially outward, and a second bearing boss Cb2 connected to the second side wall portion Cs2 and extending axially outward.

The outer side surface fs1 of the first side wall portion Cs1 and the outer peripheral surface fb1 of the first bearing boss Cb1 are connected to each other via a first corner portion R1. Further, the outer side surface fs2 of the second side wall portion Cs2 and the outer peripheral surface fb2 of the second bearing boss Cb2 are connected to each other via a second corner portion R2.

As shown in the left enlarged view of fig. 2, the first corner R1 is formed into an arc-shaped first curved surface R1. The first curved surface r1 has a cross section that is not recessed axially inward relative to the outer surface fs1 of the first side wall Cs1 and is not recessed radially inward relative to the outer peripheral surface fb1 of the first bearing boss Cb 1.

As shown in the left enlarged view of fig. 2, the second corner R2 is formed into an arc-shaped second curved surface R2. The second curved surface r2 has a cross section that is recessed axially inward relative to the outer surface fs2 of the second side wall Cs2 and recessed radially inward relative to the outer peripheral surface fb2 of the second bearing boss Cb 2. That is, the second curved surface r2 is formed to be more concave than a curve (a two-dot chain line in the enlarged view on the right side of fig. 2) connecting the outer side surface fs2 of the second side wall portion Cs2 and the outer peripheral surface fb2 of the second bearing boss Cb 2. The second curved surface r2 has a radius of curvature larger than that of the first curved surface r 1.

First and second bearings B1 and B2 are attached to outer peripheral surfaces of the first and second bearing bosses Cb1 and Cb2, respectively, and first and second output shafts 11 and 12 are inserted through inner peripheries of the first and second bearing bosses Cb1 and Cb 2.

In the differential case C, the flange portion Cf is provided so as to protrude at a position offset toward the first bearing boss Cb1 side. The ring gear 8 is fixed to the flange portion Cf by a bolt 7. Therefore, the ring gear 8 is fixed to the differential case C so as to be offset toward the first bearing boss Cb1 side in the axial direction.

The ring gear 8 meshes with a drive gear 9 of the power source. Thereby, the rotational driving force from the power source is transmitted to the differential case C via the drive gear 9 and the ring gear 8. Further, since the ring gear 8 meshes with the drive gear 9 as a helical gear, the ring gear 8 receives a radial load on the radially inner side by the meshing reaction force.

Other configurations of the differential D are well known, and therefore, the description thereof is omitted.

The operation of the embodiment will be explained. Due to the radial load to which the ring gear 8 is subjected, the shearing force acts strongly on the first corner R1 of the differential case C closer to the ring gear 8. On the other hand, the bending moment acts strongly on the second corner R2 that is farther from the ring gear 8.

In contrast, the first corner R1 is formed as an arc-shaped first curved surface R1 that is not recessed inward in the axial direction and inward in the radial direction. Therefore, the cross-sectional area of the peripheral portion of the first corner portion R1 can be secured to a large extent, and the strength against shear force is improved. On the other hand, the second corner R2 is formed as an arc-shaped second curved surface R2 that is concave inward in the axial direction and inward in the radial direction and has a large radius of curvature. Therefore, the stress concentration to the second corner portion R2 due to the bending moment is effectively suppressed.

Therefore, while rigidity against shearing force is ensured at the first corner portion R1, stress concentration due to bending moment can be reduced at the second corner portion R2.

While the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various design changes can be made without departing from the scope of the present invention.

For example, in the present embodiment, the ring gear 8 is coupled to the differential case C by the bolts 7, but the ring gear 8 may be fixed to the differential case C by welding.

In the present embodiment, the ring gear 8 and the drive gear 9 are spur gears, but may be constituted by helical gears.

Claims (1)

1. A differential, having:

a differential case (C) supported by the transmission case (10) via a first bearing (B1) and a second bearing (B2); and a differential gear mechanism (20) housed in the differential case (C) and distributing an input torque input to the differential case (C) to a first output shaft (11) and a second output shaft (12),

it is characterized in that the preparation method is characterized in that,

the differential case (C) has: a first side wall portion (Cs1) on one side in the axial direction; a second sidewall portion (Cs2) on the other side in the axial direction; a first bearing boss (Cb1) connected to the first side wall portion (Cs1) and extending axially outward; and a second bearing boss (Cb2) connected to the second side wall portion (Cs2) and extending axially outward,

a ring gear (8) that meshes with a drive gear (9) is fixed to the differential case (C) so as to be offset in the axial direction toward the first bearing boss (Cb1),

an outer side surface (fs1) of the first side wall portion (Cs1) and an outer peripheral surface (fb1) of the first bearing boss (Cb1) are connected via a first corner portion (R1), and an outer side surface (fs2) of the second side wall portion (Cs2) and an outer peripheral surface (fb2) of the second bearing boss (Cb2) are connected via a second corner portion (R2),

the first corner (R1) is formed as an arc-shaped first curved surface (R1), the first curved surface (R1) is not recessed axially inward of the outer side surface (fs1) of the first side wall (Cs1) and is not recessed radially inward of the outer peripheral surface (fb1) of the first bearing boss (Cb1),

the second corner (R2) is formed as an arc-shaped second curved surface (R2), the second curved surface (R2) is recessed axially inward of the outer side surface (fs2) of the second side wall portion (Cs2) and radially inward of the outer peripheral surface (fb2) of the second bearing boss (Cb2),

the second curved surface (r2) has a radius of curvature larger than that of the first curved surface (r 1).

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