CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Applications S.N. 62/266,453, filed December 1 1 , 2015, and S.N. 62/330,017, filed April 29, 2016, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] A locking differential can have an additional capability compared to a conventional "open" automotive differential. A motor vehicle with a locking differential can experience increased use of traction at the drive wheels compared to a motor vehicle with an "open" differential. Use of traction can be increased by restricting each of the two drive wheels on an axle to the same rotational speed without regard to the available traction or the road path taken at each wheel. The locking differential causes both wheels on an axle to turn together as if on a common axle shaft.

[0003] An open differential, or unlocked locking differential, allows each wheel on an axle to rotate at different speeds. When a motor vehicle negotiates a turn, the wheel on the smaller (inner) radius rotates more slowly than the wheel on the larger (outer) radius. Without the unlocked or open differential, one of the tires can scuff in a turn. With an open differential, when one wheel of an axle is on a slippery road surface, the wheel on the slippery surface can tend to spin while the other wheel may not have enough torque applied to it to move the motor vehicle. For example, some motor vehicles with open differentials may be unable to climb a hill with wet ice under one of the wheels no matter how dry the pavement is under the other wheel (this may be known as a split-mu surface).

[0004] In contrast, a locked differential forces wheels on both sides of the same axle to rotate together at the same speed. Therefore, each wheel can apply as much torque as the wheel/road traction and the powertrain capacity will allow. In the example of the motor vehicle on the hill with the split-mu surface, a locked differential can allow the motor vehicle to climb the hill that is impossible for an otherwise identical motor vehicle to climb with an open differential. Locking differentials can also provide better traction that leads to improved motor vehicle performance under certain conditions, for example in drag racing, or snow plow operations.

[0005] Some motor vehicles have differentials that can be reconfigured from an unlocked state to a locked state. Such motor vehicles can be operated with the differential in the unlocked state for normal conditions, for example, to prevent tire scuffing in turns, and reconfigured for operation with a locked differential when wheel slippage is encountered.

SUMMARY

[0006] A locking differential assembly includes a differential case defining an axis of rotation and a gear chamber. A first side gear is at a first end of the differential case. A second side gear is at a second end of the differential case opposite the first end for selectable rotation relative to the differential case. At least two pinion gears are rotatably supported in the gear chamber in meshing engagement with the first side gear and the second side gear. A solenoid is at the second end. An armature is selectably magnetically actuatable by the solenoid. A lock ring is selectably engagable with the second side gear to selectably prevent the side gear from rotating relative to the differential case. At least two relay pins are each connected to the lock ring and in contact with the armature to space the lock ring at least a predetermined distance from the armature.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Features of examples of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to the same or similar, though perhaps not identical,

components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear. [0008] Fig. 1 is a schematic view of a motor vehicle with a locking differential system according to an example of the present disclosure;

[0009] Fig. 2 is a perspective view of a locking differential according to an example of the present disclosure;

[0010] Fig. 3 is an exploded view of the locking differential depicted in Fig. 2;

[0011] Fig. 4A is a cross-sectional rear view of the locking differential depicted in Fig. 2;

[0012] Fig. 4B is a detail cross-sectional rear view of the portion of the locking differential indicated in Fig. 4A;

[0013] Fig. 5A is right perspective view of an example of a lock ring with relay pins according to the present disclosure;

[0014] Fig. 5B is a cross-sectional end view depicting an example of a lock ring engaged in a differential case;

[0015] Fig. 5C is a left perspective view of the example of the lock ring with relay pins depicted in Fig. 5A;

[0016] Fig. 5D is an end view of the lock ring depicted in Fig. 5A;

[0017] Fig. 5E is a cross-sectional exploded view of an example of the lock ring and a relay pin with the relay pin secured in the locking ring by a press fit;

[0018] Fig. 5F is a cross-sectional exploded view of an example of the lock ring and a relay pin with the relay pin secured in the locking ring by screw threads;

[0019] Fig. 5G is an end view of another example of a lock ring according to the present disclosure;

[0020] Fig. 5H is a cross-sectional rear view of the example of the lock ring depicted in Fig. 5G, taken along line 5H-5H;

[0021] Fig. 5I is a detail view taken as indicated in Fig. 5G;

[0022] Fig. 6 is a perspective cross sectional exploded view of the locking components of the example depicted in Fig. 2;

[0023] Fig. 7 is a perspective view of an example of a single-piece cross-shaft according to the present disclosure;

[0024] Fig. 8 is a rear view of a portion of a non-c-clip axle half-shaft; [0025] Fig. 9 is a rear view of a grooved end of a c-clip axle half-shaft;

[0026] Fig. 10 is a side view of a c-clip retainer;

[0027] Fig. 1 1 A is cross-sectional rear view of an example of an axle assembly including an example of a differential assembly with an asymmetrical half-shaft penetration of the spider gear assembly according to the present disclosure;

[0028] Fig. 1 1 B is a cross-sectional rear view of an axle assembly with an existing differential assembly for comparison to the example of the present disclosure depicted in Fig. 8A; and

[0029] Fig. 12 is a flow chart depicting an example of a method 100 of rebuilding an axle for a motor vehicle according to the present disclosure.

DETAILED DESCRIPTION

[0030] The present disclosure relates generally to locking differentials, and more particularly to electronically controlled locking differentials used in motor vehicle drive axles. As used herein, an electronically controlled locking differential means a differential that changes between an unlocked state and a locked state in response to an electronic signal. In the locked state, both axle half-shafts connected to the differential rotate together in the same direction, at the same speed. The electronic signal can be automatically produced in response to a vehicle condition, for example, detection of wheel slippage. The electronic signal can also be produced in response to a demand from an operator, for example, an operator can press a button on a control panel of the motor vehicle.

[0031] Examples of the present disclosure may allow the locking differentials disclosed herein to operate at a higher torque than similarly sized existing locking differentials. The time to actuate the locking mechanism may also be reduced compared to existing electronic locking differentials. Further, the status indicator may provide a more satisfactory user experience by providing more detailed and accurate information regarding the operation of the electronically controlled locking differential system of the present disclosure. [0032] Referring to Fig. 1 , a powertrain 5 for a motor vehicle 70 includes a motor 6, a propeller shaft 7 connected to the motor and an axle assembly 8. The propeller shaft 7 is connected, for example, by gearing (not shown) to rotationally drive the axle half-shafts 13, 13' inside the axle housing 9. The axle assembly 8 includes the axle housing 9, a locking differential assembly 10' supported in axle housing 9, a first axle half-shaft 13, and a second axle half-shaft 13' respectively connected to first and second drive wheels 98 and 98'. The first axle half-shaft 13 has a first axle half-shaft splined end 1 17 extending into the axle housing 9. (See also Fig. 8 and Fig. 1 1 A.) The second axle half-shaft 13' has a second axle half-shaft splined end 1 18 extending into the axle housing 9 opposite to the first axle half-shaft 13. A gearset 97 disposed within a differential case 12 transfers rotational power from the differential case 12 to the axle half-shafts 13, 13', and selectably allows relative rotation between the axle half-shafts 13 and 13'. Although the locking differential assembly 10' depicted in Fig. 1 is applied to a rear-wheel drive vehicle, the present disclosure may be used in transaxles for use in front-wheel drive vehicles, transfer cases for use in four-wheel drive vehicles or in any vehicle powertrain.

[0033] Referring to Figs. 2, 3, 4A and 4B together, an example of the present disclosure is depicted including a locking differential assembly 10'. The locking differential assembly 10' has a differential case 12 defining an axis of rotation 14 and a gear chamber 16. The differential case 12 rotates in the axle housing 9 (see Fig. 1 ) about the axis of rotation 14. A first side gear 20 is disposed at a first end 21 of the differential case 12 for selectable relative rotation thereto. A second side gear 18 is disposed at a second end 19 of the differential case 12 opposite the first end 21 for selectable rotation relative to the differential case 12.

[0034] The second side gear 18 has side gear dogs 22 defined on a back face 24 of the second side gear 18. The back face 24 of the second side gear 18 is opposite to a gear tooth face 66 of the second side gear 18. At least two pinion gears 26 are rotatably supported in the gear chamber 16. Each of the at least two pinion gears 26 is in meshing engagement with the first side gear 20 and the second side gear 18. [0035] The locking differential assembly 10' includes a solenoid 28, disposed at the second end 19 of the differential case 12. The solenoid 28 is retained in an annular solenoid cavity 60 defined by a stator 32. The stator 32 is formed from a

ferromagnetic material. The differential case 12 is rotatable relative to the stator 32 about the axis of rotation 14. As depicted in Fig. 4A and Fig. 4B, the stator 32 has an annular wall 33 with a longitudinal axis 35 coaxial with the axis of rotation 14. A first stator annular flange 36 extends parallel to the longitudinal axis 35 from the annular wall 33 at a first inner diameter 38 of the first stator annular flange 36. The first stator annular flange 36, the annular wall 33, and the second stator annular flange 37 define the annular solenoid cavity 60. The annular solenoid cavity 60 has an open end 63 distal to the annular wall 33. Although Fig. 4A and Fig. 4B depict the first stator annular flange 36 extending parallel to the longitudinal axis 35, the angle that the annular flange 36 makes with the annular wall 33 may deviate from 90 degrees. For example, the angle may be 45 degrees such that the annular solenoid cavity 60 is wider at the open end 63 than at the annular wall 33. The angle between the first stator annular flange 36 and the annular wall 33 may be any angle so long as the annular solenoid cavity 60 is defined by the first stator annular flange 36, the annular wall 33, and the second stator annular flange 37.

[0036] The second stator annular flange 37 extends from the annular wall 33. The second stator annular flange 37 is spaced from the first stator annular flange 36 and may be parallel to the first stator annular flange 36. The second stator annular flange 37 includes a frustoconical ridge 67 on the stator outer diameter 53 at the open end 63 of the stator 32. Although Figs. 4A and 4B depict the annular solenoid cavity 60 as having a substantially rectangular cross section, the surfaces may be rounded or canted in examples of the present disclosure. In an example, the solenoid 28 can be wound on a separate bobbin (not shown) and placed into the annular solenoid cavity 60 via the open end 63. In another example, a bobbinless solenoid can be used.

[0037] Fig. 3 and Fig. 6 depict a spring 34 disposed between the differential case 12 and the lock ring 40 to bias the lock ring 40 toward the disengaged position 44 shown at the top half of Fig. 4A. The bottom half of Fig. 4A depicts the lock ring 40 in the engaged position 45. In the example depicted in Fig. 3, the differential case 12 includes two pieces with a parting line 126 at the cross-shaft centers 52. In other examples (not shown) the parting line does not coincide with the cross-shaft centers. One of the two pieces of the differential case 12 is a flanged piece 100 with an attachment flange 105 for attaching a ring gear (not shown). The other of the two pieces of the differential case 12 is a second piece 106 upon which the solenoid 28 is mounted. A side gear thrust washer 101 is disposed between the flanged piece 100 and the first side gear 20. Thrust washers 104 are disposed between the pinion gears 26, 26' and the differential case 12. Stator retaining ring 102 is inserted into a groove in the differential case 12 to prevent the stator 32 from moving axially relative to the differential case 12. An armature retaining ring 103 is inserted into a groove on a hub 71 of the second piece 106 of the differential case 12 to limit axial movement of the armature 30 away from the stator 32. In other words, the armature retaining ring 103 is an axial hard stop for the armature 30.

[0038] In an example, the armature retaining ring 103 is substantially nonmagnetic. In an example, armature retaining ring 103 can be American Iron and Steel Institute (AISI) Type 312 Chromium-Nickel steel. Type 312 Chromium-Nickel steel is an austenitic stainless steel, and is therefore substantially non-magnetic. Therefore, the armature retaining ring 103 made from Type 312 Chromium-Nickel steel is substantially non-magnetic. As used herein, substantially non-magnetic means having a relative permeability of less than 1 .1. Relative permeability as used herein means a dimensionless ratio of permeability of a specific medium to the permeability of free space. The permeability of free space is 4π χ 10 ^"7 Newton Ampere ^-2 . Compared to a magnetic armature retaining ring, a substantially non-magnetic armature retaining ring 103 has a smaller potential for the armature retaining ring 103 to interfere with the magnetic circuit that draws the armature 30 toward the stator 32 when the solenoid 28 is energized.

[0039] Referring to Figs. 4A, 4B and 6, in examples of the present disclosure, the armature 30 is selectably magnetically actuated by the solenoid 28. The armature 30 has a ferromagnetic annular body 54. The ferromagnetic annular body 54 has an annular body axis 55 defined by the ferromagnetic annular body 54 to be aligned with the axis of rotation 14. The ferromagnetic annular body 54 has an inner flange 56 having an inner annular bevel 57 at a beveled end 58 of the ferromagnetic annular body 54. The inner annular bevel 57 is parallel to the chamfer 73 of the first stator annular flange 36. The ferromagnetic annular body 54 further includes an outer flange 59 having an outer annular bevel 61 . An annular armature central flange 62 extends radially inward from the inner flange 56. The annular armature central flange 62 has an armature central flange diameter 64 smaller than the armature outer diameter 69. A pilot flange 65 extends from an intersection of the annular armature central flange 62 and the inner flange 56. The pilot flange 65 is to guide the armature 30 as the armature 30 moves along the axis of rotation 14 relative to the stator 32.

[0040] In an example, the at least two relay pins 50 contact the annular armature central flange 62 to drive the lock ring 40 toward engagement with the second side gear 18 when the solenoid 28 is energized.

[0041] In examples of the present disclosure, the armature 30 is selectably translatable relative to the stator 32 along the axis of rotation 14. The rotating armature 30 may rotate relative to the stator 32, although the armature 30 is not fixed for rotation with the differential case 12.

[0042] As depicted in Fig. 4B, Fig. 5A, Fig. 5C and Fig. 6, at least two relay pins 50 each include a cylindrical rod portion 74 having a post end 77 and a contact end 79 opposite the post end 77, the cylindrical rod portion 74 defines a longitudinal rod axis 75 at a center 76 of the cylindrical rod portion 74. The relay pins 50 each have a post 78 having a smaller free state post diameter 80 than a diameter 94 of the cylindrical rod portion 74 defined at the post end 77. As used herein, "free state" means that the component is not in compression or tension from contact with another component. Therefore, the free state post diameter 80 may be slightly larger than the post diameter after the post 78 has been installed into a relay pin attachment bore 84 with a press fit. After press-fit installation, the post diameter compresses slightly and the relay pin attachment bore enlarges slightly until the two diameters are equalized by the stress of the press fit. The post 78 is concentric with the cylindrical rod portion 74. [0043] Referring now to Figs. 4A, 4B, 5A, 5B, 5C, and 6 together, in examples of the present disclosure, the locking differential assembly 10' has a lock ring 40. The lock ring 40 includes complementary dogs 42 defined around an engagement face 43 of the lock ring 40. The complementary dogs 42 are selectably engagable with the side gear dogs 22 by translating the lock ring 40 along the axis of rotation 14 from a disengaged position 44 to an engaged position 45. The lock ring 40 has a plurality of lugs 46 defined on an outside surface 47 of the lock ring 40. Each lug 48 is to slide in a respective complementary slot 49 defined in the differential case 12 to guide the translation of the lock ring 40 between the engaged position 45 and the disengaged position 44. (See Fig. 5B.) The fit of the plurality of lugs 46 in the respective complementary slots 49 also prevents rotation of the lock ring 40 relative to the differential case 12.

[0044] The top half of Fig. 4A depicts an example of the present disclosure with the lock ring 40 in the disengaged position 44. The bottom half of Fig. 4A depicts the lock ring 40 is in the engaged position 45. In examples of the present disclosure, the second side gear 18 is substantially prevented from rotating relative to the differential case 12 when the lock ring 40 is in the engaged position 45. "Substantially prevented from rotating relative to the differential case 12" means that a small amount of relative rotation may occur, however the relative rotation is less than about 5 degrees. The second side gear 18 is free to rotate relative to the differential case 12 when the lock ring 40 is in the disengaged position 44. The lock ring 40 has a lock ring thickness 41 (Fig. 5A) parallel to the axis of rotation 14.

[0045] The lock ring 40 defines a quantity of relay pin attachment bores 84 equal to a quantity of the relay pins 50 The relay pin attachment bores 84 are centered on a radial line at a predetermined radius 31 from the axis of rotation 14 through a center of a respective lug 48 (Fig. 5D). Each relay pin 50 is retained in the respective relay pin attachment bore 84. In an example, the plurality of lugs 46 is a quantity of six lugs 48, and the quantity of relay pins 50 is three.

[0046] As depicted in Fig. 5E, in an example, a free state post diameter 80 of the post 78 of each relay pin 50 is larger than a free state bore diameter 39 of each relay pin attachment bore 84 to form a press fit between the post 78 of each relay pin 50 and the respective relay pin attachment bore 84. In an example, there is an American National Standards Institute (ANSI) B4.2-1978 H7/s6 medium drive fit between the post 78 of each relay pin 50 and the respective relay pin attachment bore 84.

[0047] As depicted in Fig. 5F, in an example, the post 78 of each relay pin 50 has a first screw thread 87 defined thereon. Each relay pin attachment bore 84 can have a second screw thread 85 complementary to the first screw thread 87 defined therein. Each relay pin 50 can be threadingly fastened to the lock ring 40 via engagement of the first screw thread 87 with the second screw thread 85.

[0048] Each lug 48 may have two opposed faces 86 symmetrically arranged about a radial line 81 perpendicular to the axis of rotation 14. The two opposed faces may each be arcs of a circle having a center 72 on the radial line 81 from the axis of rotation 14 through the center of the respective lug 48. In examples, an angle 99 between the two opposed faces can be from about 28 degrees to about 32 degrees. In examples having the two opposed faces 86 being arcs of a circle, the angle 99 between the two opposed faces is defined herein as the angle between the tangents to the arcs at the respective midpoints of the arcs.

[0049] In the example of the lock ring 40' depicted in Figs. 5G, 5H, and 5I, each of the two opposed faces 86 is defined by a portion of a respective cylindrical surface 82 between a root fillet 83 and a top land 107. The top land 107 is defined at a tip diameter 108. The portion of the respective cylindrical surface 82 is defined at a cylinder radius 1 16 from about 8mm to about 16 mm. The portion of the respective cylindrical surface 82 is defined about a respective cylindrical axis 109 parallel to the axis of rotation 14. The respective cylindrical axis 109 intersects a respective centerpoint 1 10 defined at an intersection of a respective offset line 1 1 1 and an offset radial arc 1 12. The respective offset line 1 1 1 is defined parallel to the radial line 81 perpendicular to the axis of rotation 14 and spaced from the radial line 81

perpendicular to the axis of rotation 14 by an offset length 1 14 from about 1 mm to about 1 .5 mm. The offset radial arc 1 12 is centered at the axis of rotation 14 and has a radial length 1 15 from about 4 mm to about 7 mm less than one half of the tip diameter 108. In an example, the plurality of lugs 46 is a quantity of six lugs 48.

[0050] Examples of the present disclosure may have a cross-shaft 90 (also known as a cross-shaft assembly herein) disposed perpendicularly to the axis of rotation 14 of the differential case 12 to support an opposed pair 27 of the at least two pinion gears

26 for rotation of the opposed pair 27 of the at least two pinion gears 26 on the cross- shaft (assembly) 90. Referring to Figs. 3 and 7, in examples of the present disclosure with a 4-pinion differential, the differential assembly 10 may include a plurality of stub shafts 92. Each stub shaft 92 can be equally spaced around an annular yoke 91 . The plurality of stub shafts 92 can be disposed perpendicularly to the axis of rotation 14 of the differential case 12. The plurality of stub shafts 92 and the annular yoke 91 can compose a single forging 1 13. The plurality of stub shafts 92 support an opposed pair

27 of the at least two pinion gears 26 and another opposed pair 27' of the at least two pinion gears 26 for rotation of the four pinion gears 26 on the respective stub shafts 92.

[0051] Returning back to Fig. 1 , an electrical switch 17 may be disposed on the motor vehicle 70 to selectably close a circuit 23 to provide electrical power to the solenoid 28. The switch 17 shown in Fig. 1 is a rocker switch, however any switch capable of controlling the flow of power through the solenoid 28 may be used. The switch 17 may be a low current switch that controls a relay or transistor that directly controls power through the solenoid 28. An electronic status indicator 29 may be disposed in the motor vehicle 70. An electronic driver circuit 25 may be disposed on the motor vehicle 70 to power the electronic status indicator 29 to indicate a status of the locking differential system 1 1. In an example, the status may include at least three states. For example, the electronic status indicator 29 may be a selectably illuminated indicator 88, and the status may be indicated by a flash code. To illustrate, the selectably illuminated indicator 88 may include a light emitting diode, incandescent lamp, fluorescent lamp, or other selectably illuminable light source.

[0052] The present disclosure also includes an axle assembly with an offset differential cross-shaft yoke and axle half-shafts that are asymmetric with respect to the spider gear assembly 133. As used herein, the spider gear assembly means a set of components consisting of the cross-shaft assembly 90 and the pinion gears 26 as depicted in Fig. 3. The axle housing is typically sized together with the ring gear, drive pinion, and differential case to provide adequate clearance between the moving parts and the axle housing; however, such clearance is minimized to reduce the overall weight of the axle assembly.

[0053] In a non-C-clip axle, the axle half-shafts are fixed laterally to the axle housing 9 near the wheel ends 141 of the axle half-shafts. As shown in Fig. 8, the first axle half-shaft 13 has a first axle half-shaft splined end 1 17. Similarly, the second axle half-shaft 13' has a second axle half-shaft splined end 1 18, as shown semi- schematically in Fig. 1 1 A. The splined ends of the axle half-shafts fit into mating splines 134, 135 in the side gears 18, 20. In an axle with a typical non-C-clip differential, there is clearance between the splined end 1 17, 1 18 of the axle half-shaft 13, 13' and the differential cross-shaft. Fig. 1 1 B depicts a typical non-C-clip axle without the improvements of the present disclosure. Typically, there is an equal amount of clearance between each splined end 1 17, 1 18 of the axle half-shafts 13, 13' and the cross-shaft. As such, the splined ends 1 17, 1 18 of the axle half-shafts 13, 13' are symmetrically spaced from the cross-shaft in a typical non-C-clip axle. The axle half-shafts 13, 13' are typically designed to have a length that does not cause the axle half-shaft 13, 13' to extend beyond the side gear 18, 20.

[0054] In some C-clip axles, each C-clip axle half-shaft 138 is constrained laterally in one direction by a C-clip 136 (Fig. 10) cooperating with a groove in the axle half- shaft (Fig. 9). The C-clip 136 abuts the side gear in a pocket (not shown) on the central end 123 of the side gear. (See Fig. 4A.) The cylindrical wall of the pocket (not shown) in the side gear prevents the C-clip 136 from sliding radially out of the groove 137 in the C-clip axle half-shaft 138. The abutment of the C-clip 136 on the side gear prevents the C-clip axle half-shaft 138 from moving laterally toward the wheel end. To prevent the C-clip axle half-shaft 138 from moving laterally away from the wheel end (i.e. toward the center of the vehicle), a typical C-clip axle half-shaft 138 may abut the cross-shaft. Thus, in order to remove the C-clip axle half-shaft 138, the cross-shaft is removed from the differential case and the C-clip axle half-shaft 138 is moved to the center to expose the C-clip 136 beyond the cylindrical wall of the pocket in the side gear. Next the C-clip 136 is removed and the C-clip axle half-shaft 138 is withdrawn from the axle housing. It is to be understood that the present disclosure is not applicable to C-clip axles.

[0055] The differential in an axle may be replaced as a repair or upgrade. For example, a two-pinion, limited slip differential may be replaced with a four-pinion, electronic locking differential as disclosed herein. Off-roading enthusiasts may desire the durability and torque characteristics of a four pinion differential or the convenience of an electronic locking differential. To reduce the cost and time to complete the upgrade of the differential, it may be desirable to re-use the existing axle half-shafts 13, 13' without modification of the existing axle half-shafts 13, 13'.

[0056] To maintain clearance between the upgraded differential case and the axle housing 9, the external dimensions of the upgraded differential case may be about the same as the differential case that is being replaced. The side gears and the spider gear assembly 133 may be shifted to accommodate the electromagnetic actuator 142 within the external envelope of the differential assembly that is being replaced (for example, the differential assembly depicted in Fig. 1 1 B). As used herein, the first end 21 is the end of the differential case 12 that is nearest to the ring gear attachment flange 105; the second end 19 is the end of the differential case 12 that is opposite the end closest to the ring gear attachment flange 105. In an example of the present disclosure, the cross-shaft assembly 90 is shifted toward the first end 21 of the differential case 12. For example, the cross-shaft assembly 90 may be shifted toward the first end 21 by about 1 millimeter (mm) to about 1 1 mm. Shifting the cross-shaft assembly 90 toward the first end 21 causes the side gears 18, 20 to be shifted by the same amount in the same direction. Assuming the axle half-shafts 13, 13' are not changed from the axle half-shafts 13, 13' used prior to the repair or upgrade, the first axle half-shaft 13 on the first end 21 will protrude through the first side gear 20 toward the cross-shaft assembly 90 of the upgraded differential 10". As disclosed herein, to maintain clearance between the splined end 1 17 of the first axle half-shaft 13 and the cross-shaft assembly 90, the cross-shaft has a hollow annular yoke 91 . As disclosed herein, the aperture 139 in the annular yoke 91 is large enough to clear the protruding end 140 of the first axle half-shaft 13.

[0057] Referring to Figs. 2, 3 and 4A together, an example of the present disclosure is depicted including a differential assembly 10. The example depicted in Figs. 2, 3 and 4A is an electronic locking differential assembly 10", however, it is to be understood that non-locking differentials and non-electronic locking differentials are included in the present disclosure. The differential assembly 10 has a differential case 12 having an axis of rotation 14 and a gear chamber 16. The differential case 12 rotates in the axle housing 9 (see Fig. 1 1A) about the axis of rotation 14. A first side gear 20 is disposed in the differential case 12 for selectable relative rotation thereto. The first side gear 20 defines a first internal spline 128 having a first internal spline major diameter 129. A second side gear 18 is disposed in the differential case 12 for selectable relative rotation thereto. The second side gear 18 defines a second internal spline 131 having a second internal spline major diameter 132. A cross-shaft assembly 90 is disposed in the differential case 12. The cross-shaft assembly 90 has an annular yoke 91 defining an inside clearance cylinder 130. The inside clearance cylinder 130 is coaxial to the axis of rotation 14 of the differential case 12. An inside clearance diameter 95 of the inside clearance cylinder 130 is greater than the first internal spline major diameter 129 or the second internal spline major diameter 132. The cross-shaft assembly 90 includes a plurality of stub shafts 92. The stub shafts 92 are equally spaced around the annular yoke 91. The stub shafts 92 are disposed perpendicularly to the axis of rotation 14 of the differential case 12.

[0058] Examples of the differential assembly 10 of the present disclosure can include at least two pinion gears 26 rotatably supported in the differential case 12. In the example of the differential assembly 10 depicted in Figs. 2, 3 and 4A together, the at least two pinion gears 26 includes four pinion gears 26 and the plurality of stub shafts 92 includes four stub shafts 92. In other examples of the present disclosure (not shown), the at least two pinion gears 26 may include two pinion gears 26, three pinion gears 26 or any number of pinion gears 26 greater than one. As depicted in Figs. 2, 3 and 4A together, each of the at least two pinion gears 26 are in meshing engagement with the first side gear 20 and the second side gear 18. Each of the at least two pinion gears 26 is rotatably attached to a respective stub shaft 92.

[0059] In the example of the differential assembly 10 depicted in Figs. 2, 3 and 4A together, the cross-shaft assembly 90 consists of a single forging 1 13 defining the annular yoke 91 and the plurality of stub shafts 92. Each stub shaft 92 defines a respective stub shaft centerline 93 at a central axis of each stub shaft 92. The stub shaft centerlines 93 extend radially out from the annular yoke 91 . The respective stub shaft centerlines 93 together define a cross-shaft plane 96. The differential case 12 is split into a first portion 124 of the differential case 12 and a second portion 125 of the differential case 12 with a parting line 126 defined between the first portion 124 of the differential case 12 and the second portion 125 of the differential case 12 at the cross- shaft plane 96.

[0060] As best observed in Fig. 4A of the present disclosure, the first side gear 20 is disposed in the first portion 124 of the differential case 12 for selectable relative rotation thereto. The second side gear 18 is disposed in the second portion 125 of the differential case 12 opposite the first portion 124 of the differential case 12 for selectable rotation relative to the differential case 12. The first side gear 20 has a central end 123 defined on a central side 121 facing the cross-shaft plane 96 and the first side gear 20 has a distal side 122 facing opposite the central side 121 . The first side gear 20 is to receive a first axle half-shaft splined end 1 17 of a first axle half-shaft 13 for driving engagement therebetween. (See Fig. 8 and Fig. 1 1A.) The first axle half-shaft 13 protrudes through the first side gear 20 beyond the central end 123 by a protruding length 127. In an example of the present disclosure, the protruding length 127 may range from about 1 mm to about 1 1 mm. In an example, the protruding length 127 may be about 6 mm. In another example, the protruding length 127 may be about 2 mm. The first axle half-shaft 13 can be to protrude into the inside clearance cylinder 130.

[0061] As depicted in Fig. 1 1 A, an example of the present disclosure includes an axle assembly 8 for a motor vehicle 70. The axle assembly 8 has a differential assembly 10 as disclosed herein and also depicted in Fig. 1 and Fig. 1 1 A. The differential assembly 10 includes a differential case 12 having an axis of rotation 14 supported in the axle housing 9. A cross-shaft assembly 90 is disposed in the differential case 12. Fig. 7 depicts an example of a cross-shaft assembly 90 according to the present disclosure. The cross-shaft assembly has an annular yoke 91 . The cross-shaft assembly 90 has a plurality of stub shafts 92. The stub shafts 92 are equally spaced around the annular yoke 91 . The stub shafts 92 are disposed perpendicularly to the axis of rotation 14 of the differential case 12. Each stub shaft 92 defines a respective stub shaft centerline 93. The respective stub shaft centerlines 93 together define a cross-shaft plane 96. The cross-shaft plane 96 is parallel to the medial plane 1 19 and the cross-shaft plane 96 is spaced from the medial plane 1 19 by an offset distance 120.

[0062] The axle assembly 8 includes an axle housing 9 having the differential assembly 10 supported therein. The axle assembly 8 has a first axle half-shaft 13 having a first axle half-shaft splined end 1 17 extending into the axle housing 9. The axle assembly 8 has a second axle half-shaft 13' having a second axle half-shaft splined end 1 18 extending into the axle housing 9. A medial plane 1 19 is defined in the axle housing 9 midway between the first axle half-shaft splined end 1 17 and the second axle half-shaft splined end 1 18. The cross-shaft plane 96 may be parallel to the medial plane 1 19. The cross-shaft plane 96 may be spaced from the medial plane 1 19 by an offset distance 120.

[0063] In the example of the present disclosure depicted in Fig. 1 1 A, the axle assembly 8 includes a first side gear 20 disposed in the differential case 12. The first side gear 20 defines a first internal spline 128 having a first internal spline major diameter 129. A second side gear 18 is disposed in the differential case 12. The second side gear 18 defines a second internal spline 131 having a second internal spline major diameter 132. An inside clearance cylinder 130 is defined by the annular yoke 91 . The inside clearance cylinder 130 is coaxial to the axis of rotation 14 of the differential case 12. An inside clearance diameter 95 of the inside clearance cylinder 130 is greater than the first internal spline major diameter 129 or the second internal spline major diameter 132.

[0064] In the example of the present disclosure depicted in Fig. 1 1 A, the at least two pinion gears 26 are rotatably supported in the differential case 12. Each of the at least two pinion gears 26 is in meshing engagement with the first side gear 20 and the second side gear 18. Each of the at least two pinion gears 26 is rotatably attached to a respective stub shaft 92. The at least two pinion gears 26 can include four pinion gears 26 and the plurality of stub shafts 92 can include four stub shafts 92. The cross- shaft assembly 90 can consist of a single forging 1 13 defining the annular yoke 91 and the plurality of stub shafts 92. In other examples, the cross-shaft assembly can include the plurality of stub shafts 92 joined to the annular yoke 91 by fasteners, welding or adhesives. The differential assembly 10 in the axle assembly 8 depicted in Fig. 1 1A is a locking differential assembly 10'. In particular, the locking differential assembly 10' depicted in Fig. 1 1A is an electronic locking differential assembly 10". The differential case 12 is split into a first portion 124 of the differential case 12 and a second portion 125 of the differential case 12 with a parting line 126 defined between the first portion 124 of the differential case 12 and the second portion 125 of the differential case 12 at the cross-shaft plane 96. (See Fig. 2.)

[0065] In the example of the present disclosure depicted in Fig. 1 1 A, the first side gear 20 is disposed in the first portion 124 of the differential case 12 for selectable relative rotation thereto. The second side gear 18 is disposed in the second portion 125 of the differential case 12 opposite the first portion 124 of the differential case 12 for selectable rotation relative to the differential case 12. The first side gear 20 has a central end 123 defined on a central side 121 facing the cross-shaft plane 96 and a distal side 122 facing opposite the central side 121 . The first side gear 20 receives the first axle half-shaft splined end 1 17 for driving engagement therebetween. The first axle half-shaft 13 protrudes through the first side gear 20 beyond the central end 123 by a protruding length 127.

[0066] Fig. 12 is a flow chart depicting an example of a method 200 of rebuilding an axle for a motor vehicle according to the present disclosure. The method 200 includes removing a first axle half-shaft from the axle as depicted in Box 210, and removing a second axle half-shaft from the axle as depicted in Box 220. It is not necessary to completely remove the axle half-shafts; it is sufficient to slide the axle half-shafts out far enough to disengage from the differential assembly. The axle half-shafts may be completely removed from the axle for inspection. Next, the method 200 includes removing an existing differential assembly from the axle as shown at Box 230. If an axle half-shaft is broken, it may be possible to remove the differential assembly from the axle prior to removing the outer portion of the axle half-shaft; however, the broken axle half-shaft will eventually be removed as part of the rebuilding of the axle. The method 200 continues with installing an electronic locking differential assembly 10" as depicted in Box 240. The method 200 includes reinstalling the first axle half-shaft on the axle without modification to the first axle half-shaft as shown at Box 250. The method 200 also includes reinstalling the second axle half-shaft on the axle without modification to the second axle half-shaft as depicted at Box 260. In case an axle half- shaft is broken, a replacement half-shaft may be installed at the reinstalling step. The replacement half-shaft has substantially the same dimensions as the broken half-shaft prior to the axle half-shaft becoming broken. Substantially the same dimensions means that the spatial dimensions of the half-shafts are within manufacturing variation limits. According to the method of the present disclosure, as depicted at Box 270, a medial plane 1 19 is defined in the axle housing 9 of the axle assembly 8 midway between the first axle half-shaft splined end 1 17 and the second axle half-shaft splined end 1 18. The electronic locking differential assembly 10" includes a cross-shaft assembly 90 disposed in a differential case 12. The cross-shaft assembly 90 has an annular yoke 91 and a plurality of stub shafts 92. The stub shafts 92 are equally spaced around the annular yoke 91 . Each of the stub shafts 92 is disposed

perpendicularly to an axis of rotation 14 of the differential case 12. Each stub shaft 92 defines a respective stub shaft centerline 93. The respective stub shaft centerlines 93 together define a cross-shaft plane 96. The cross-shaft plane 96 is parallel to the medial plane 1 19. The cross-shaft plane 96 is spaced from the medial plane 1 19 by an offset distance 120. Thus, the method 200 of the present disclosure allows the replacement of a differential assembly with an upgraded differential assembly 10" of the present disclosure without requiring substitution or modification of the first axle half-shaft.

[0067] It is to be understood that the terms "connect/connected/connection" and/or the like are broadly defined herein to encompass a variety of divergent connected arrangements and assembly techniques. These arrangements and techniques include, but are not limited to (1 ) the direct communication between one component and another component with no intervening components therebetween; and (2) the communication of one component and another component with one or more components therebetween, provided that the one component being "connected to" the other component is somehow in operative communication with the other component (notwithstanding the presence of one or more additional components therebetween).

[0068] In describing and claiming the examples disclosed herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0069] It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range. For example, a range from about 28 degrees to about 32 degrees should be interpreted to include not only the explicitly recited limits of about 28 degrees and about 32 degrees, but also to include individual values, such as 29 degrees, 30 degrees, 31 degrees, etc., and sub-ranges, such as from about 28 degrees to about 31 degrees, etc. Furthermore, when "about" is utilized to describe a value, this is meant to encompass minor variations (up to +/- 10%) from the stated value.

[0070] Furthermore, reference throughout the specification to "one example", "another example", "an example", and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise. [0071] While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.