WO2024170150A1

WO2024170150A1 - Friction clutch mechanism for electronic locking differential

Info

Publication number: WO2024170150A1
Application number: PCT/EP2024/025079
Authority: WO
Inventors: Ram PALASKAR; Mohit AGGARWAL; Andrew EDLER; Gabriela Florentina RADULESCU; Jordan Robert Allen; Matthew G. Fox
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2023-02-17
Filing date: 2024-02-16
Publication date: 2024-08-22
Anticipated expiration: 2025-08-17
Also published as: DE112024000891T5; KR20250149999A; CN120677322A

Abstract

The present disclosure relates to an electronic locking differential gear mechanism having a lock detection mechanism for sensing and indication of a locked and unlocked state of the locking mechanism. The electronic locking differential gear mechanism includes an electronic stator which, when activated, makes frictional contact with a grooved surface of a ramped collar, whereby the ramped collar is rotated about an axis of the mechanism. The ramps of the ramped collar axially displace a plurality of push rods, which displace a locking collar and cause it to engage with a locker gear, placing the mechanism in a locked state.

Description

FRICTION CLUTCH MECHANISM FOR ELECTRONIC LOCKING DIFFERENTIAL

BACKGROUND OF THE INVENTION

[0001] Vehicle drivetrains may include differential mechanisms which include gear sets that allow torque to be applied differently to wheels of the same axle during operation of the vehicle. In some instances (for example, low traction road conditions such as ice, mud, snow, etc.), it may be desired to include a locking mechanism in the differential so that all torque is delivered equally to both wheels of the axle. Locking differentials, including electronic locking differentials, are generally known in the art. For locking differentials, an adequate amount of drag torque between interacting components may be needed for durable engagement of the locking mechanism.

SUMMARY

[0002] In some aspects, a locking mechanism is included in the differential mechanism so that all available torque is delivered equally to both wheels of the axle, locking both wheels in synchronous rotation with each other. The locking mechanism may include a rotatable ramped collar which contacts a stator housing surface, the contact causing a drag torque which alters the rotational speed of the ramped plate and causes the locking mechanism to engage. A surface feature which increases friction and drag torque between the ramped collar and the stator housing surface may cause more efficient locking and may increase engagement durability and performance for a given duty cycle.

[0003] Accordingly, the present application describes, in an example aspect, a differential assembly comprising: a first housing; a first half-axle output; a second half-axle output; a power input location; a gear set disposed within the first housing and operably connecting the first half-axle output, the second half-axle output, and the power input location together; and an electrically activated locking assembly including a second housing mounted to the first housing and being operable between a locked position, in which the first and second axle half-axle outputs are prevented from rotating relative to each other, and an unlocked position, in which the first and second half-axle outputs are enabled to rotate relative to each other, wherein the locking assembly includes a stator mounted within the second housing, a rotatable ramped collar actuated by the stator, a plurality of push rods axially displaceable by rotation of the ramped collar, and a locking collar axially displaceable by movement of the plurality of push rods, wherein when the locking assembly is in the locked condition, a grooved surface of the ramped collar is in frictional contact with the second housing, wherein when the locking assembly is in the locked position, the locking collar is engaged with a locker gear of the gear set, wherein when the locking assembly is in the unlocked position, the locking collar is disengaged from the locker gear.

[0004] In an aspect, the ramped collar of the differential assembly is located axially between the stator and the locker gear.

[0005] In an aspect, the ramped collar of the differential assembly comprises one or more ramp valleys and one or more ramp peaks on a second surface opposite the grooved surface.

[0006] In an aspect, when the locking assembly of the differential assembly is in the locked condition, the plurality of push rods are axially displaced and contact the one or more ramp peaks at a first end.

[0007] In an aspect, the grooved surface of the differential assembly comprises a spiral groove.

[0008] In an aspect, the groove of the differential assembly is machined into the ramped collar.

[0009] In an aspect, when the locking assembly of the differential assembly is in the unlocked condition, the grooved surface of the ramped collar is free from contact with the second housing.

[0010] In an aspect, when the locking assembly of the differential assembly is in the locked condition, the grooved surface of the ramped collar is in frictional contact with at least one interface surface of the second housing.

[0011] In an aspect, the second housing of the differential assembly is not rotatable with respect to the first housing.

[0012] In an aspect, activation by the stator causes the ramped collar of the differential assembly to rotate about the axis.

[0013] In an aspect, the stator of the differential assembly is enclosed on at least two sides by the second housing, and the stator remains free from contact with the grooved surface.

[0014] The present application describes, in an example aspect, a locking system for a differential assembly, the locking system comprising: a locking element of the differential assembly, operable between a locked state and an unlocked state; one or more push rods displaceable along an axis of the differential assembly, connected at a first end to a locking collar of the locking element and in contact at a second end with a rotatable ramped collar, wherein: the rotatable ramped collar is rotatable about the axis, the rotatable ramped collar comprises one or more ramp valleys and one or more ramp peaks, and the one or more push rods are displaceable by the one or more ramp valleys and one or more ramp peaks; a stator mounted within a stator housing, wherein the rotatable ramped collar is actuated by the stator, wherein in the locked state, a grooved surface of the ramped collar is in frictional contact with the stator housing, wherein in the locked state, the locking collar is engaged with a locker gear of the locking element, and wherein in the unlocked state, the locking collar is disengaged from the locker gear.

[0015] In an aspect, the grooved surface of the locking system comprises a spiral groove.

[0016] In an aspect, when the locking assembly of the locking system is in the unlocked state, the grooved surface of the ramped collar is free from contact with the stator housing.

[0017] In an aspect, when the locking assembly of the locking system is in the locked state, the grooved surface of the ramped collar is in frictional contact with at least one interface surface of the stator housing.

[0018] In an aspect, the at least one interface surface of the locking system includes two concentric ring-shaped interface surfaces.

[0019] In an aspect, activation by the stator of the locking system causes the ramped collar to rotate about the axis.

[0020] The present application describes, in an example aspect, a method of locking a differential assembly, the method comprising: receiving a voltage signal at a stator; rotating a ramped collar about an axis of the differential assembly, via activation from the stator; contacting a grooved surface of the ramped collar with an interface surface of a stator housing, causing a drag torque between the grooved surface and the interface surface; displacing a push rod along the axis, the push rod in contact with the ramped collar at a first end, by the rotation of the ramped collar; and displacing a locking collar of a locking element along the axis by the displacement of the push rod, wherein the locking collar is connected to the push rod at a second end.

[0021] In an aspect, the method further comprises maintaining the stator housing in a nonrotated position. [0022] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Non-limiting and non- exhaustive examples are described with reference to the following Figures.

[0024] FIG. 1 illustrates a perspective view of an electronic locking differential gear mechanism, constructed in accordance with principles of this disclosure, according to an example.

[0025] FIG. 2 illustrates a side view of the electronic locking differential gear mechanism of FIG. 1 , according to an example.

[0026] FIG. 3 illustrates a cross-sectional view of the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0027] FIG. 4 illustrates a perspective exploded view of the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0028] FIG. 5 illustrates a close-up cross-sectional view of a portion of the electronic locking differential gear mechanism of FIG. 1 , showing details of the ramped collar and the stator assembly, according to an example.

[0029] FIG. 6 illustrates a rear perspective view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0030] FIG. 7 illustrates a front perspective view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0031] FIG. 8 illustrates a front view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0032] FIG. 9 illustrates a rear view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0033] FIG. 10 illustrates a side view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example. [0034] FIG. 11 illustrates a cross-sectional view of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0035] FIG. 12 illustrates a close-up, perspective cross-sectional view of the front surface of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0036] FIG. 13 illustrates a cross-sectional view of surface grooves of the front surface of a ramped collar for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0037] FIG. 14 illustrates a rear perspective view of a stator assembly for a locking differential gear mechanism of FIG. 1, according to an example.

[0038] FIG. 15 illustrates a front perspective view of a stator assembly for a locking differential gear mechanism of FIG. 1, according to an example.

[0039] FIG. 16 illustrates a rear view of a stator assembly for a locking differential gear mechanism of FIG. 1, according to an example.

[0040] FIG. 17 illustrates a front view of a stator assembly for a locking differential gear mechanism of FIG. 1, according to an example.

[0041] FIG. 18 illustrates a side view of a stator assembly for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0042] FIG. 19 illustrates a cross-sectional view of a stator assembly for the electronic locking differential gear mechanism of FIG. 1, according to an example.

[0043] FIG. 20 illustrates a schematic view of a vehicle within which the electronic locking differential gear mechanism may be used.

DETAILED DESCRIPTION

[0044] In the following detailed description, references are made to the accompanying drawings that form a part hereof, and in which are shown, by way of illustrations, specific embodiments or examples. These aspects may be combined, other aspects may be utilized, and structural changes may be made without departing from the present disclosure. Examples may be practiced as methods, systems, or devices. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and their equivalents. [0045] Vehicle drivetrains may include differential mechanisms which include gear sets that allow torque to be applied differently to wheels of the same axle during operation of the vehicle. In some aspects, a driveshaft transferring torque from an engine or motor may, via a drive pinion gear, transfer torque to a ring gear of a transmission (for example, mounted to a flange of the transmission) by engagement with the ring gear. This ring gear is in a meshing engagement with a plurality of inner pinion gears (or spider gears) 52. In an aspect, the inner pinion gears 52 are in a meshing engagement with two side gears 54, 56, each side gear additionally having internal splines 58, 60 corresponding to a half-axle output (for example, to left rear axle 111 and right rear axles 112). In an aspect, the ring gear is located outside of a case or housing, and the gear set (which operably connects the half-axle outputs and the power input location (driveshaft) together), including the inner pinion gears 52 and side gears 54, 56, are located within the case/housing.

[0046] In some aspects, a locking mechanism is included in the differential mechanism so that all available torque is delivered equally to both wheels of the axle, locking both wheels in synchronous rotation with each other. In some aspects, the locking mechanism is moved between a locked state and an unlocked state by an electrical action. In some aspects, the electrical action includes an electric stator. In some aspects, a driver or other user of a vehicle may trigger the electrical locking mechanism by way of a button, switch, or similar interactive device.

[0047] Referring to FIG. 20, an example vehicle drivetrain is shown in accordance with the above description and disclosure and within which the disclosed electronic locking differential gear assembly 10 may be used. As shown, the vehicle drive line is provided with a power plant 106, such as an internal combustion engine or electric motor, a transmission 107, and a power transfer unit 108 that are operatively connected at the front of the vehicle to transmit torque directly to a front left axle 100, and front right axle 101 such that wheels 102 and 103 receive torque to provide traction to the vehicle via wheel hubs 1 15 and 116. Via mechanisms in the power transfer unit 108, such as a hypoid gear and pinion, a drive shaft 109 receives torque and transmits it to the rear of the vehicle. As shown, an all-wheel drive coupling 120 connects to the drive shaft 109, and a rear drive unit 110 may house the disclosed locking differential assembly 10 within a rear differential assembly. As discussed further herein, the locking differential assembly 10 may be operated in either an open or locked mode. In the open mode, a left rear wheel 113, via wheel hub 117 and a left rear axle I l l, can spin at a speed that is different from a right wheel 114. Likewise, the right rear wheel 114, via wheel hub 118 and a right rear axle 112, can spin at a different speed than left rear wheel 113. In the locked mode, both left and right rear wheels 113 and 114 receive the same torque because the left and right rear axles 1 11 and 112 are locked together to prevent relative rotation via internal components in the rear differential. An example of a differential mechanism is described in further detail in U.S. Patent No. 9,657,827 B2, the entire disclosure of which, except for any definitions, disclaimers, disavowals, and inconsistencies, is incorporated herein by reference.

[0048] Shown in the Figures is an electronic locking differential gear mechanism (e.g., differential assembly) 10 that includes cam/ramp actuated electronic locking capability. A gear set 50 of the electronic locking differential gear mechanism 10 is located within a case 20 (refer to FIG. 1), and in some examples, torque may be transferred to the gear set 50 via a ring gear mounted to a flange 23. Accordingly, the flange 23 may be referred to a power input location. [0049] In an aspect, an electric actuator mechanism (e.g., electrically actuated locking assembly or locking element) 12 of the electronic locking differential gear mechanism 10 includes a stator housing 40. The stator housing 40 is mounted to the case (e.g., housing) 20. The stator housing 40 is operable between a locked state, in which first and second half-axle outputs (for example, left rear axle 111 and right rear axle 112) are prevented from rotating relative to each other, and an unlocked state, in which the first and second half-axle outputs are enabled to rotate relative to each other. Stator housing 40 includes an electric stator 16, which, in some aspects, causes a ramped collar 18 to be rotationally actuated in relation to the stator housing 40. In an aspect, ramped collar 18 rotates about an axis X (refer to FIG. 3).

[0050] In the open, unlocked position, the ramped collar 18 and the stator housing 40 do not contact each other and there may be a gap 70 between them (refer to FIG. 5). In the locked position, when a voltage signal is received at the stator 16, the ramped collar 18 and stator housing 40 will be in frictional contact with each other. A front interface surface 66 of the ramped collar 18 will contact an interface surface(s) 64 of the stator housing.

[0051] In some aspects, stator housing 40 has a substantially U-shaped cross section (refer to FIGs. 5, 19). The stator (coil) 16 fits within and is enclosed on three sides by stator housing 40. Stator housing 40 may have two ring-shaped interface surfaces 64 that face (and contact, in the locked position) the front interface surface 66 of the ramped collar 18. An unenclosed surface 68 of stator coil 16 is recessed into the stator housing 40, compared to the interface surfaces 64, and the unenclosed surface 68 does not contact front interface surface 66 even when in the locked state.

[0052] In the locked position, when the ramped collar 18 and stator housing 40 are in frictional contact with each other, the front interface surface 66 and interface surface(s) 64 are in frictional contact with each other. This frictional contact generates drag torque between the ramped collar 18 and the stator housing 40, which decreases the ramped collar 18 rotational speed relative to the case 20, which in-tum causes push rods 14 to be actuated (as described below) and ultimately locking of the differential assembly 10. If friction is not sufficient between front interface surface 66 and interface surface(s) 64 (for example, due to misalignment of parts, oil hydroplaning, or smoothening of surfaces), the drag torque generated may not be sufficient for locking.

[0053] In some aspects, the stator housing 40 is configured to comprise a material of high hardness and is configured so that the interface surface(s) 64 are of low roughness. In some examples, the interface surface(s) 64 are characterized by an Ra value of 0.5 pm or less. In some examples, the interface surface(s) 64 are characterized by an Rz value of 4.0 pm or less. In some examples, the interface surface(s) 64 are characterized by an Ra value of 3.2 pm or less. In some examples, the interface surface(s) 64 are characterized by a flatness value of 0. 13 pm or less.

[0054] In some aspects, front interface surface 66 of ramped collar 18 is configured to have a surface effect of low hardness and a surface effect of high roughness. In some aspects, referring at least to FIGs. 7, 8, 12, and 13, the front interface surface 66 of ramped collar 18 includes grooves 72 that may increase physical friction and/or that may break oil film to maintain a friction surface. In some aspects, grooves 72 are machined onto the front interface surface 66. In some aspects, grooves 72 are machined in a spiral design. The spiral design may be anticlockwise. The spiral design may be anticlockwise from an inside perimeter 74 of the front interface surface 66 to an outer perimeter 76 of the front interface surface 66.

[0055] In some aspects, grooves 72 maintain friction between the front interface surface 66 and the interface surfaces 64, even as peaks of the grooves 72 are smoothed out gradually by wear, especially where the differential assembly 10 is kept in the locked state for long durations. In some aspects, the spiral groove 72 depth is defined such that that a peak of the groove is present on the front interface surface 66 to maintain the required friction (for example, adequate friction for engagement and locking even if wear occurs on the peaks). This may aid in both the longevity of the ramped collar 18 and the reliability and efficiency of the locking mechanism.

[0056] Referring to FIGs. 12 and 13, the spiral groove 72 includes multiple peaks and valleys. In the particular example shown, the valley is arc-shaped, although other shapes (for example, rectangular) may be contemplated in other examples. In some examples, the radius R of the arc may be 0.4 mm, plus or minus machine tolerances. In some examples, the radius R of the arc is between 0.3 mm and 0.5 mm, plus or minus machine tolerances. In some examples, the radius R of the arc is between 0.2 mm and 0.8 mm, plus or minus machine tolerances. The radius of the tool top nose utilized to machine the spiral groove 72 onto front interface surface 66 may impact the radius R.

[0057] A distance DI between the center points of the peaks of spiral groove 72 may be substantially consistent throughout the spiral groove 72. In some examples, the peak-to-peak distance D 1 may be 0.6 mm, plus or minus machine tolerances. In some examples, the distance DI may be between 0.5 mm to 0.7 mm, plus or minus machine tolerances. In some examples, the distance DI may be between 0.3 mm to 0.9 mm, plus or minus machine tolerances. In some examples, the distance DI may be between 0.6 mm to 0.8 mm, plus or minus machine tolerances.

[0058] In some examples, the peaks may be flat, pointed, or rounded. In the particular example shown, the peaks are flat. In some examples, a width D2 of the flat top of the peaks of spiral groove 72 is 0.16 mm, plus or minus machine tolerances. In some examples, the peak width D2 is 0. 12 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be between 0.12 mm to 0.16 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be between 0.11 mm to 0.17 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be between 0.07 mm to 0.18 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be 0.14 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be between 0.10 mm and 0.14 mm, plus or minus machine tolerances. In some examples, the peak width D2 may be between 0. 14 mm and 0. 18 mm, plus or minus machine tolerances.

[0059] In some examples, a depth D3 of the valley of the spiral groove 72 is 0.10 mm, plus or minus machine tolerances. In some examples, the peak depth D3 is 0.07 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be between 0.07 mm to 0.10 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be between 0.06 mm to 0.11 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be between 0.05 mm to 0.12 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be 0.085 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be between 0.05 mm and 0.085 mm, plus or minus machine tolerances. In some examples, the peak depth D3 may be between 0.085 mm and 0.12 mm, plus or minus machine tolerances.

[0060] In some aspects, grooves 72 maintain friction between the front interface surface 66 and the interface surfaces 64 at least in part by breaking oil film, which may help maintain drag torque and may improve stability of locking performance at high-speed conditions. This may additionally aid in both the longevity of the ramped collar 18 and the reliability and efficiency of the locking mechanism.

[0061] Referring at least to FIGs. 4, 6, and 10, in an aspect, ramped collar 18 includes one or more ramps (for example, one or more locations axially where it has a greater or lesser length). Ramped collar 18 includes one or more ramp valleys 17, where the axial length of the ramped collar 18 is the least. Ramped collar 18 includes one or more ramp peaks 19, where the axial length of the ramped collar 18 is the greatest.

[0062] In some examples, the electronic locking differential 10 includes at least one actuating push rod 14. Although three push rods 14 are depicted in the example embodiments of the figures (refer to FIG. 4), other embodiments may include more than three push rods 14 or fewer than three push rods 14. Push rods 14 are operably coupled to electric stator 16 via the ramped collar 18. In some aspects, push rods 14 may be generally cylindrical or rod-like in shape. Push rods 14 contact ramped collar 18 at an and of the push rods 14. In some aspects, push rods 14 pass through the case 20 in a bore, and do not rotate with relation to the case 20. [0063] Push rods 14 are coupled to a locking collar 24. In some examples, push rods 14 are coupled to locking collar 24 via press fit design, threaded connection, or any suitable fastening or attachment means, or, in some examples, without any positive connection.

[0064] Push rods 14 are axially displaceable along (parallel to) the axis X of the differential assembly 10. Push rods 14 are axially displaceable by the rotation of the ramped collar 18. Locking collar 24 is axially displaceable by the displaced movement of the push rods 14. By use of the term axial or axially displaceable, it is meant to define a direction that is parallel to the longitudinal axis X of the differential assembly 10. [0065] Locking collar 24 includes teeth 26 formed on an inner diameter of the locking collar 24, which selectively engage with external teeth 27 of a locker gear 28. When the teeth 26 of locking collar 24 engage with the external teeth 27 of locker gear 28, the electronic locking differential gear mechanism 10 is placed into a locked position. When the teeth 26 of locking collar 24 are disengaged from the external teeth 27 of locker gear 28, the electronic locking differential gear mechanism 10 is placed into an unlocked position.

[0066] The locking collar 24 is disposed within a cavity defined at an outer boundary by the gear case 20 and defined at an inner boundary by the locker gear 28.

[0067] In some aspects, the locking collar 24 is biased to a disengaged or unlocked position by a spring or other biasing force member.

[0068] In an aspect, each of the push rods 14, in contact with ramped collar 18 at an end, is at an initial position (corresponding to an unlocked state) with its end in contact with a ramp valley 17. As ramp collar 18 is rotated about axis 2, each of the push rods 14 is displaced axially toward locker gear 28, as the end in contact with ramped collar 18 is moved to a maximally displaced position in contact with a ramp peak 19 (corresponding to a locked state). This displaces locking collar 24 toward locker gear 28, allowing teeth 26 and external teeth 27 to engage.

[0069] In some examples, the electronic locking differential gear mechanism 10 includes a sensor assembly to determine the locking state/status (for example, locked or unlocked) of the electronic locking differential gear mechanism 10.

[0070] In an aspect, stator housing 40 includes one or more anti-rotation lugs or tabs 46 formed or attached thereon. Stator housing 40 may be stationary (non-rotatable) in relation to the case 20.

[0071] In an example use, the electric actuator mechanism 12 is in a normal, unlocked status. For example, it may be biased to an unlocked state by a spring 78 or other biasing element. In the unlocked state, locking collar 24 is moved axially away from engagement with locker gear 28.

[0072] Upon activation/ energizing (which may be in response to a control signal from a control module or may be actuated in response to activation of a switch by a user) of the electric stator 16, the ramped collar 18 is rotated about axis X, and at least one push rod 14 is displaced axially. As shown at FIG. 4, a bearing assembly 62 can be provided in the inner perimeter opening of stator housing 40 and an inner disc portion of ramped collar 18 to facilitate relative movement between the components. Locking collar 24 is moved by the displacement of the one or more push rods 14 to engage with the locker gear 28, which causes the locking of the electronic locking differential gear mechanism 10.

[0073] In some aspects, after the electric stator 16 is de-energized, the electronic locking differential gear mechanism 10 is returned to an unlocked position (for example, by a biasing element or spring 78), and gap 70 will again be present between front interface surface 66 and interface surface(s) 64.

[0074] For the purposes of this application, terms such as “left,” “right,” “front,” “back,” “upper,” “lower,” “upward,” and “downward” are intended to be descriptive with reference to and in relation to the orientation shown in the Figures for clarity and are not meant to be limiting, but the examples as practiced and included in the scope of the claims may include examples where the systems and devices are in a different orientation.

[0075] While particular uses of the technology have been illustrated and discussed above, the disclosed technology can be used with a variety of environments in accordance with many examples of the technology. The above discussion is not meant to suggest that the disclosed technology is only suitable for implementation within the environments shown and described above. For examples, while certain technologies described herein were primarily described in the context of sealed battery cases, technologies disclosed herein are applicable to sealed components generally.

[0076] This disclosure described some aspects of the present technology with reference to the accompanying drawings, in which only some of the possible aspects were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the aspects set forth herein. Rather, these aspects were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible aspects to those skilled in the art.

[0077] As should be appreciated, the various aspects described with respect to the Figures herein are not intended to limit the technology to the particular aspects described. Accordingly, additional configurations can be used to practice the technology herein and/or some aspects described can be excluded without departing from the methods and systems disclosed herein. [0078] Similarly, where operations of a process are disclosed, those operations are described for purposes of illustrating the present technology and are not intended to limit the disclosure to a particular sequence of operations. For example, the operations can be performed in differing order, two or more operations can be performed concurrently, additional operations can be performed, and disclosed operations can be excluded without departing from the present disclosure. Further, each operation can be accomplished via one or more sub-operations. The disclosed processes can be repeated.

[0079] Although specific aspects were described herein, the scope of the technology is not limited to those specific aspects. One skilled in the art will recognize other aspects or improvements that are within the scope of the present technology. Therefore, the specific structure, acts, or operations are disclosed only as illustrative aspects. The scope of the technology is defined by the following claims and any equivalents therein.

Claims

Claims: What is claimed is:

1. A differential assembly comprising: a) a first housing; b) a first half-axle output; c) a second half-axle output; d) a power input location; e) a gear set disposed within the first housing and operably connecting the first half-axle output, the second half-axle output, and the power input location together; and f) an electrically activated locking assembly including a second housing mounted to the first housing and being operable between a locked position, in which the first and second axle half-axle outputs are prevented from rotating relative to each other, and an unlocked position, in which the first and second half-axle outputs are enabled to rotate relative to each other; wherein the locking assembly includes a stator mounted within the second housing, a rotatable ramped collar actuated by the stator, a plurality of push rods axially displaceable by rotation of the ramped collar, and a locking collar axially displaceable by movement of the plurality of push rods; wherein when the locking assembly is in the locked position, a grooved surface of the ramped collar is in frictional contact with the second housing; wherein when the locking assembly is in the locked position, the locking collar is engaged with a locker gear of the gear set; wherein when the locking assembly is in the unlocked position, the locking collar is disengaged from the locker gear.

2. The differential assembly of claim 1, wherein the ramped collar is located axially between the stator and the locker gear.

3. The differential assembly of claim 1, wherein the ramped collar comprises one or more ramp valleys and one or more ramp peaks on a second surface opposite the grooved surface.

4. The differential assembly of claim 3, wherein when the locking assembly is in the locked position, the plurality of push rods are axially displaced and contact the one or more ramp peaks at a first end.

5. The differential assembly of claim 1, wherein the grooved surface comprises a spiral groove.

6. The differential assembly of claim 5, wherein the spiral groove is machined into the ramped collar.

7. The differential assembly of claim 1, wherein when the locking assembly is in the unlocked position, the grooved surface of the ramped collar is free from contact with the second housing.

8. The differential assembly of claim 1, wherein when the locking assembly is in the locked position, the grooved surface of the ramped collar is in frictional contact with at least one interface surface of the second housing.

9. The differential assembly of claim 1, wherein the second housing is not rotatable with respect to the first housing.

10. The differential assembly of claim 1 , wherein activation by the stator causes the ramped collar to rotate about the axis.

11. The differential assembly of claim 1, wherein the stator is enclosed on at least two sides by the second housing, and wherein the stator remains free from contact with the grooved surface.

12. A locking system for a differential assembly, the locking system comprising: a locking element of the differential assembly, operable between a locked state and an unlocked state; one or more push rods displaceable along an axis of the differential assembly, connected at a first end to a locking collar of the locking element and in contact at a second end with a rotatable ramped collar, wherein: the rotatable ramped collar is rotatable about the axis, the rotatable ramped collar comprises one or more ramp valleys and one or more ramp peaks, and the one or more push rods are displaceable by the one or more ramp valleys and one or more ramp peaks; a stator mounted within a stator housing, wherein the rotatable ramped collar is actuated by the stator; wherein in the locked state, a grooved surface of the ramped collar is in frictional contact with the stator housing; wherein in the locked state, the locking collar is engaged with a locker gear of the locking element; and wherein in the unlocked state, the locking collar is disengaged from the locker gear.

13. The locking system of claim 13, wherein the grooved surface comprises a spiral groove.

14. The locking system of claim 13, wherein when the locking assembly is in the unlocked state, the grooved surface of the ramped collar is free from contact with the stator housing.

15. The locking system of claim 13, wherein when the locking assembly is in the locked state, the grooved surface of the ramped collar is in frictional contact with at least one interface surface of the stator housing.

16. The locking system of claim 15, wherein the at least one interface surface includes two concentric ring-shaped interface surfaces.

17. The locking system of claim 13, wherein activation by the stator causes the ramped collar to rotate about the axis.

18. A method of locking a differential assembly, the method comprising: receiving a voltage signal at a stator; rotating a ramped collar about an axis of the differential assembly, via activation from the stator; contacting a grooved surface of the ramped collar with an interface surface of a stator housing, causing a drag torque between the grooved surface and the interface surface; displacing a push rod along the axis by the rotation of the ramped collar, the push rod in contact with the ramped collar at a first end; and displacing a locking collar of a locking element along the axis by the displacement of the push rod, wherein the locking collar is connected to the push rod at a second end.

19. The method of claim 18, further comprising: maintaining the stator housing in a non-rotated position.