Electronic locking differential

Abstract

A locking differential transitions between a locked configuration and an unlocked configuration by an axially movable locking device. The locking device includes a pin for maintaining a constant distance between the locking plate and the magnetisable armature. Energizing the electromagnet can attract the armature, so that the whole locking device is pulled to a locking structure. After energization is stopped, the spring biases the locking device back to the non-locked configuration.

Description

Cross-references to related applications

[0001] This application claims priority to Indian Provisional Application No. 202311065490, filed on September 29, 2023, and Indian Provisional Application No. 202411065511, filed on August 30, 2024; the disclosures of these two applications are hereby incorporated in their entirety by reference. Background Technology

[0002] During normal operation of a motor vehicle, all four wheels typically do not rotate at the same rate. Different wheel speeds most commonly occur when the vehicle is cornering, but can also be caused by braking or uneven road conditions. To accommodate these different wheel speeds while continuously transmitting power to both wheels, a differential is constructed to allow for different wheel speeds between the driven wheels. The differential allows the wheels to rotate at different rates while simultaneously transmitting torque to each wheel.

[0003] While this solution may be satisfactory under certain driving conditions, it is unsatisfactory when one of the driven wheels experiences a surface with a lower coefficient of friction than the other wheels(s). This can prevent torque from being applied to the wheel with higher friction, resulting in unsatisfactory vehicle performance. A locking mechanism can be provided to lock the differential and prevent different wheel speeds, and in at least some cases, distribute torque evenly between the two wheels. Summary of the Invention

[0004] According to certain aspects of this disclosure, a differential assembly includes: a stator including an electromagnet; a gearbox configured to rotate relative to the stator; a differential gear set disposed within the gearbox, the differential gear set including a locking gear; and a locking device disposed within the gearbox. The locking device includes: a locking member, an armature, a biasing member, and a pin. The locking member is disposed within the gearbox. The locking member is movable relative to the locking gear between a locked position and an unlocked position. The armature is disposed outside the gearbox. The armature is axially movable relative to the stator between a first position and a second position. The armature is configured to move to the second position when the electromagnet is energized. The biasing member is configured to bias the armature to the first position. The pin extends between the locking member and the armature. The pin is configured to maintain a separation distance between the locking member and the armature such that the locking device, as a unit, is axially movable relative to the gearbox. When the armature is in the first position, the locking member is in the unlocked position, and when the armature is in the second position, the locking member is in the locked position.

[0005] In some examples, the biasing member is located outside the gearbox. In other examples, the biasing member is located inside the gearbox.

[0006] In some examples, the locking member includes a locking ring with radial teeth. In other examples, the locking member includes a locking plate with axial teeth.

[0007] According to certain aspects of this disclosure, a differential assembly includes a locking device movable relative to a gearbox. The locking device includes a locking plate, an armature, and a pin. The locking plate is movable relative to a locking gear within the gearbox between a locked position and an unlocked position. When in the locked position, the locking plate engages with the locking gear, thereby rotatably securing the locking plate and the locking gear together. When in the unlocked position, the locking plate is rotatable relative to the locking gear. The armature includes an armature axially movable between a first position and a second position. The armature is biased in the first position. The armature is made of a magnetizable material (e.g., a ferromagnetic material). A first end of the pin is axially fixed to the locking plate, while a second end of the pin is axially fixed to the armature.

[0008] In some implementations, a locking plate is disposed on the side of the differential gear set opposite the armature. In some examples, the locking plate is disposed within the differential housing, while the armature is disposed outside the gear housing. In some examples, a pin extends through the differential housing between the locking plate and the armature.

[0009] In some embodiments, the pin is one of a plurality of pins. The first end of each pin is axially fixed to the locking plate, while the second end of each pin is axially fixed to the armature.

[0010] In some implementations, the pin may be threaded, clamped (e.g., using a snap ring), press-fitted, welded, fastened (e.g., with a threaded screw, set screw, cotter pin or other pin) or otherwise secured to the armature and / or locking plate.

[0011] According to other aspects of this disclosure, a method of operating a locking differential includes: energizing an electromagnet to attract an iron armature from a first position to a second position against a bias force; and moving the locking plate and the armature synchronously by pulling a pin connecting the locking plate and the armature, thereby moving the locking plate from an unlocked position to a locked position.

[0012] In some embodiments, the method further includes de-energizing the electromagnet so that the bias force can move the armature back to the first position.

[0013] According to other aspects of this disclosure, a locking differential includes: a stator including an electromagnet; a gearbox configured to rotate relative to the stator; a differential gear set including a locking gear; and a locking device mounted to the gearbox. The locking device includes: a locking plate; an armature; a biasing member; and a pin. The locking plate is disposed within the gearbox. The locking plate is movable relative to the locking gear between a locked position and an unlocked position. The armature is disposed outside the gearbox. The armature is configured to rotate with the gearbox relative to the stator. The armature is axially movable relative to the stator between a first position and a second position. The armature is configured to move to the second position when the electromagnet is energized. The biasing member is disposed between the stator and the armature to bias the armature to the first position. The pin extends between the locking plate and the armature. The pin is configured to maintain a separation distance between the locking plate and the armature such that when the armature is in the first position, the locking plate is in the unlocked position, and when the armature is in the second position, the locking plate is in the locked position.

[0014] In some implementations, the biasing member is located outside the differential housing.

[0015] The following description will set forth several additional inventive aspects. These inventive aspects may relate to a single feature, as well as combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and do not limit the broad inventive concepts on which the embodiments disclosed herein are based. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate several aspects of this disclosure. A brief description of the drawings is as follows: Figure 1 This is a cross-sectional view of an exemplary locking differential, which includes a locking device constructed in accordance with the principles of this disclosure.

[0017] Figure 2 yes Figure 1 The perspective view of the locking differential in the image shows the housing removed for easier observation of the locking mechanism.

[0018] Figure 3 yes Figure 1 A magnified view of a portion of the image.

[0019] Figure 4 It is applicable Figure 1 A perspective view of an example pin of a locking device.

[0020] Figure 5 It is applicable Figure 1 A perspective view of an example locking plate of a locking device.

[0021] Figure 6It is applicable Figure 1 A perspective view of an example locking gear of a locking device.

[0022] Figure 7 It is applicable Figure 1 A perspective view of an example armature of a locking device.

[0023] Figure 8 yes Figure 3 A magnified view of a portion of the pin, only the second end of which has been modified to press into the armature mounting position.

[0024] Figure 9 Display settings Figure 8 The weld at the installation location.

[0025] Figure 10 The pin is shown being held in place at the armature mounting position using a first-class fastener.

[0026] Figure 11 The pin is shown being held in place at the armature mounting position using a second type of fastener.

[0027] Figure 12 The pin is shown being held in place at the armature mounting position using a third type of fastener.

[0028] Figure 13 The indicator pin is loosely positioned within the channel of the locking differential housing.

[0029] Figure 14 This is a perspective view of another example locking differential, which includes a locking device constructed in accordance with the principles of this disclosure.

[0030] Figure 15 yes Figure 14 The first perspective view of the locking differential components after they are unfolded away from each other.

[0031] Figure 16 yes Figure 14 The second perspective view shows the components of the locking differential unfolded away from each other.

[0032] Figure 17 It is applicable Figure 14 A first perspective view of an example locking device for a locking differential, the locking device including a locking plate, an armature and a plurality of pins.

[0033] Figure 18 yes Figure 17 A second perspective view of the locking device.

[0034] Figure 19 yes Figure 14 A cross-sectional view of the locking differential.

[0035] Figure 20This is a perspective view of another example locking differential, which includes a locking device constructed in accordance with the principles of this disclosure.

[0036] Figure 21 yes Figure 20 The first perspective view of the locking differential components after they are unfolded away from each other.

[0037] Figure 22 yes Figure 20 The second perspective view shows the components of the locking differential unfolded away from each other.

[0038] Figure 23 It is applicable Figure 20 A first perspective view of an example locking device for a locking differential, the locking device including a locking plate, an armature and a plurality of pins.

[0039] Figure 24 yes Figure 23 A second perspective view of the locking device.

[0040] Figure 25 yes Figure 20 A cross-sectional view of the locking differential.

[0041] Figure 26 It is a perspective view of a gear housing with a physical stop that limits travel.

[0042] Figure 27 Showing Figure 26 How do the physical stops in the stator maintain the gap between the armature and the stator? Detailed Implementation

[0043] Exemplary aspects of this disclosure as illustrated in the accompanying drawings will now be described in detail. Throughout the drawings, the same reference numerals will be used wherever possible to refer to the same or similar parts.

[0044] Figure 1Locking differentials 100, 200, and 300 for vehicles are shown. The locking differentials 100, 200, and 300 include gearboxes 102, 202, and 302 (e.g., gear housings 104, 204, and 304, and end caps 106, 206, and 306), which are configured to rotate about a longitudinal axis L. Torque input to the locking differentials 100, 200, and 300 is transmitted via an input ring gear (not shown) to flanges 105, 205, and 305 of the gearboxes 102, 202, and 302. Rotatable housings 102, 202, and 302 define gear chambers 112, 212, and 312, in which differential gear sets 114, 214, and 314 are disposed. The differential gear sets 114, 214, and 314 include first-side gears 126, 226, and 326 and second-side gears 128, 228, and 328, which are connected together by pinions.

[0045] Gearboxes 102, 202, and 302 define annular hub portions 108, 208, 308 and 110, 210, and 310, to which the left and right axles are respectively connected. A pair of bearing assemblies (not shown) located at the annular hub portions 108, 208, 308, 110, 210, and 310 provide rotational support for the rotary differential assembly 100, 200, and 300 relative to an external differential housing or "bracket" (not shown). In some embodiments, thrust sleeves 207 and 307 are disposed between the first-side gear 226 and the housing 202 (e.g., end cap 206). Thrust sleeves 207 and 307 prevent wear on end caps 206 and 306.

[0046] Locking differentials 100, 200, and 300 can operate in either a locked or unlocked mode. In locked mode, one or both side gears of the differential gear sets 114, 214, and 314 are locked relative to gearboxes 102, 202, and 302 and cannot rotate. In unlocked mode, side gears 126 and 128 can rotate freely relative to gearboxes 102, 202, and 302. For example, the first side gears 126, 226, and 326, and the second side gears 128, 228, and 328 can be configured to rotate independently about the longitudinal axis L of gearboxes 102, 202, and 302. In some embodiments, the locking differentials 100, 200, and 300 are manually switched between locked and unlocked modes by a user. In other embodiments, the locking differentials 100, 200, and 300 automatically switch between locked and unlocked modes (e.g., by the vehicle's microprocessor based on perceived vehicle operating conditions).

[0047] Locking differentials 100, 200, and 300 include locking devices 118, 218, and 318, which are switchable between a locking configuration and an unlocked configuration. When in the locking configuration, locking devices 118, 218, and 318 prevent side gears 126, 226, and 326 from rotating independently relative to gearboxes 102, 202, and 302. When in the unlocked configuration, locking devices 118, 218, and 318 allow side gears 126, 226, and 326 to rotate independently relative to gearboxes 102, 202, and 302.

[0048] In some embodiments, locking devices 118, 218, 318 include armatures 119, 219, 319 and locking members 122, 222, 322, which are spaced apart by one or more pins 124, 224, 324 (e.g., pull rods / push rods). Figure 1-19 In the example shown, locking devices 118, 218, and 318 include three pins 124, 224, and 324. Figure 20-26 In the example shown, locking devices 118, 218, 318 include four pins 124, 224, 324. Other configurations are also possible. Pins 124, 224, 324 are configured to maintain a constant distance between armatures 119, 219, 319 and locking members 122, 222, 322. Locking members 122, 222, 322 engage with gearboxes 102, 202, 302, thereby causing locking members 122, 222, 322 to rotate synchronously with gearboxes 102, 202, 302. When locking devices 118, 218, 318 are configured in the locking configuration, locking members 122, 222, 322 are configured to engage with locking gears 130, 230, 330. When the locking devices 118, 218, and 318 are in the non-locking configuration, the locking members 122, 222, and 322 disengage from the locking gears 130, 230, and 330. In some embodiments, the locking gears 130, 230, and 330 are integrated with the side gears 126, 226, and 326.

[0049] In some embodiments, pins 124, 224, 324 extend through channels 103, 203, 303 in gearboxes 102, 202, 302 defined between locking members 122, 222, 322 and armatures 119, 219, 319 (see, for example, see...). Figure 13 In some embodiments, pins 124, 224, and 324 fit tightly within channels 103, 203, and 303 (see, for example, see...). Figure 1 In other embodiments, pins 124, 224, and 324 are loosely fitted within channels 103, 202, and 303 (see, for example, see...). Figure 13In some examples, channels 103, 203, and 303 extend through most of gear chambers 112, 212, and 312. In other examples, channels 103, 203, and 303 are interrupted at gear chambers 112, 212, and 312 (see, for example, see...). Figure 26 In some examples, channels 103, 203, and 303 are interrupted by windows in housing 302.

[0050] Armatures 119, 219, and 319 include mounting stations 148, 248, and 348, where pins 124, 224, and 324 are received. Armatures 119, 219, and 319 are configured to rotate with gearboxes 102, 202, and 302 relative to stators 134, 234, and 334. Pins 124, 224, and 324 provide torque to armatures 119, 219, and 319. Armatures 119, 219, and 319 are axially movable relative to stators 134, 234, and 334 between a first position and a second position. Stators 134, 234, and 334 are located externally to gearboxes 102, 202, and 302. For example, stators 134, 234, and 334 may form a ring around annular hub portions 110, 210, and 310. Gearboxes 102, 202, and 302 rotate relative to stators 134, 234, and 334. Snap rings 136 and 236 axially hold stators 134, 234, and 334 in gearboxes 102, 202, and 302 (e.g., at annular hub portions 110, 210, and 310). Locking members 122, 222, and 322 are provided within gearboxes 102, 202, and 302.

[0051] In some embodiments, locking devices 118, 218, 318 are biased to a non-locking configuration by biasing members 140, 240, 340 (e.g., wave springs). In some embodiments, locking devices 118, 218, 318 overcome the bias of biasing members 140, 240, 340 by electromagnets 132, 232, 332, and switch from a non-locking configuration to a locked configuration. In some examples, armatures 119, 219, 319 are made of ferromagnetic or other magnetizable materials. When electromagnets 132, 232, 332 are energized, they attract armatures 119, 219, 319, causing them to move axially relative to gearboxes 102, 202, 302 along axis L. Armatures 119, 219, and 319, along with the remainder of locking devices 118, 218, and 318, move axially as a unit, thereby axially moving locking members 122, 222, and 322 into the locking configuration. Since locking devices 118, 218, and 318 move integrally with armatures 119, 219, and 319, the state of the locking devices (e.g., locked or unlocked) can be determined based on the positions of armatures 119, 219, and 319. In some embodiments, the positions of armatures 119, 219, and 319 can be determined based on inductance.

[0052] In some examples, electromagnets 132, 232, and 332 are disposed at stators 134, 234, and 334. Stators 134, 234, and 334 are disposed outside gearboxes 102, 202, and 302. Armatures 119, 219, and 319 are also disposed outside gearboxes 102, 202, and 302. For example, armatures 119, 219, and 319 may be annular members surrounding annular hub portions 110. In these examples, armatures 119, 219, and 319 may span gearboxes 102, 202, and 302 during axial movement.

[0053] In some embodiments, locking devices 118, 218, 318 and gearboxes 102, 202, 302 are configured to prevent armatures 119, 219, 319 from contacting stators 134, 234, 334. For example, gearboxes 102, 202, 302 may be configured to limit the travel of locking members 122, 222, 322 by physical stops, and thus limit the travel of locking devices 118, 218, 318. In one example, the physical stop includes shoulders 109, 209, 309 defined by differential housings 102, 202, 302 (see, for example, see...). Figure 26 and Figure 27In one example, when the locking devices 118, 218, 318 are in the unlocked configuration, the shoulders 109, 209, 309 are spaced apart from the locking members 122, 222, 322 by a distance D. This distance D is less than the distance between the armatures 119, 219, 319 and the stators 134, 234, 334 (see, for example, [reference needed]). Figure 27 Therefore, the limited stroke prevents the locking devices 118, 218, 318 from sliding a sufficient distance to bring the armatures 119, 219, 319 into contact with the stators 134, 234, 334. Maintaining a gap (e.g., an air cap) between the armatures 119, 219, 319 and the stators 134, 234, 334 reduces the frictional resistance to the torque applied to the gearboxes 102, 202, 302.

[0054] In some examples, biasing members 140, 240, and 340 are disposed outside gearboxes 102, 202, and 302 (see, for example, see...). Figure 1 For example, biasing members 140, 240, and 340 may be disposed between stators 134, 234, and 334 and armatures 119, 219, and 319. In one example, one axial end of biasing member 140, 240, and 340 may contact armatures 119, 219, and 319, while the opposite axial end of biasing member 140, 240, and 340 may contact stators 134, 234, and 334, or contact bushings 141 (e.g., washers) adjacent to stators 134, 234, and 334 (e.g., see [link]). Figure 3 In one example, bushing 141 suppresses wear on bias members 140, 240, 340 that would result from relative rotation between the bias member and the stator. In other examples, bias members 140, 240, 340 may be disposed inside gearboxes 102, 202, 302 (see, for example, see...). Figure 13 For example, biasing members 140, 240, and 340 may be disposed between locking members 122, 222, and 322 and gearboxes 102, 202, and 302. In some examples, biasing members 140, 240, and 340 are disposed around side gears 126, 226, and 326.

[0055] In some embodiments, locking devices 118, 218, 318 are assembled as a unit movable relative to gear sets 114, 214, 314 and gearboxes 102, 202, 302. In some embodiments, locking members 122, 222, 322 have an outer periphery configured to engage with the inner surface of gearboxes 102, 202, 302 to rotatably secure the locking members 122, 222, 322 to gearboxes 102, 202, 302 while allowing axial movement of the locking members 122, 222, 322 relative to gearboxes 102, 202, 302. In some examples, locking members 122, 222, 322 include one or more lugs 142, 242, 342 that slide along corresponding recesses 144, 244, 344 defined by gearboxes 102, 202, 302 (e.g., gear housings 104, 204, 304). The engagement between the ears 142, 242, 342 and the grooves 144, 244, 344 prevents rotation between the locking members 122, 222, 322 and the gearboxes 102, 202, 302. The lengths of the grooves 144, 244, 344 are sufficient to accommodate movement of the locking members 122, 222, 322 between the locked and unlocked configurations.

[0056] In some embodiments, locking members 122, 222, 322 are also configured to engage locking gears 130, 230, 330 when disposed in a locking configuration. In some embodiments, locking member 122 includes a locking ring having an inner periphery that defines teeth 146 or other protrusions that engage with the teeth of locking gear 130. In some examples, locking gear 130 is formed on the outer periphery of side gear 126. When in the locking configuration, locking member 122 is axially positioned to be sufficiently radially aligned with locking gear 130 so that teeth 146 engage with locking gear 130. The engagement between teeth 146 and locking gear 130, and the engagement between lug 142 and recess 144, causes locking gear 130, and thus side gear 126, to rotate synchronously with gearbox 102. When in the unlocked configuration (e.g., see...), Figure 1 The locking member 122 is axially spaced and radially misaligned with the locking gear 130, such that the teeth 146 of the locking member 122 do not mesh with the locking gear 130. Therefore, the locking gear 130 and thus the side gear 126 can rotate independently of the gearbox 102 and the locking member 122.

[0057] In other embodiments, locking members 222, 322 include locking plates having teeth 246, 346 (e.g., dog teeth) that axially engage with the teeth of locking gears 230, 330. In some examples, locking gears 230, 330 are positioned on the side of side gears 226, 326 opposite to the gear teeth. When in the locked configuration, locking members 222, 322 are axially positioned to engage the axial teeth 246, 346 with locking gears 230, 330. The engagement between teeth 246, 346 and locking gears 230, 330, and the engagement between ears 242, 342 and grooves 244, 344, causes locking gears 230, 330, and therefore side gears 226, 326, to rotate synchronously with gearboxes 202, 302. When in the unlocked configuration, the locking members 222, 322 are axially spaced from the locking gears 230, 330, such that the teeth 246, 346 of the locking members 222, 322 do not engage with the locking gears 230, 330 (see, for example). Figure 19 and Figure 25 Therefore, locking gears 230, 330 and thus side gears 226, 326 can rotate independently of gearboxes 202, 302 and locking members 222, 322.

[0058] In some embodiments, locking members 122, 222, 322 include a plurality of mounting positions 148, 248, 348, at which a first end 123 of pins 124, 224, 324 is fixedly received. In some embodiments, the first end 123 of pins 124, 224, 324 extends through the mounting positions 148, 248, 348 and is clipped onto locking members 122, 222, 322 (e.g., using snap rings or other fasteners). In other embodiments, the first end 123 of pins 124, 224, 324 may be press-fitted, welded, fastened, or otherwise secured to the mounting positions 148, 248, 348. In some embodiments, mounting positions 148, 248, 348 are formed in lugs 142, 242, 342 of locking members 122, 222, 322. In some examples, only some of the ear portions 142, 242, 342 form mounting positions 148, 248, 348. In some embodiments, the ear portions 142, 242, 342 that form mounting positions 148, 248, 348 are larger than the other ear portions 142, 242, 342. In other embodiments, the mounting positions 148, 248, 348 may be spaced apart from the ear portions 142, 242, 342.

[0059] In some embodiments, the armatures 119, 219, 319 of the locking devices 118, 218, 318 have a first axial end facing the gear set and a opposing second axial end away from the gear set. The armatures 119, 219, 319 define a plurality of mounting positions 160, 260, 360 at the first axial end. The mounting positions 160, 260, 360 are configured to receive and axially secure the second ends 125 of the pins 124, 224, 324. In some embodiments, the mounting positions 160, 260, 360 are configured to form a defined connection with the second ends 125 of the pins 124, 224, 324. In some embodiments, each mounting position 160, 260, 360 defines an orifice sized to receive the second ends 125 of the pins 124, 224, 324. In some embodiments, each mounting position 160, 260, 360 includes a raised edge surrounding the orifice. In some examples, mounting positions 160, 260, and 360 can be straight. In other examples, mounting positions 160, 260, and 360 can be tapered.

[0060] In some examples, mounting positions 160, 260, and 360 are provided with threaded holes into which the second end 125 of pins 124, 224, and 324 can be secured (see, for example, see...). Figure 3 In other examples, mounting positions 160, 260, and 360 are provided with orifices into which the second end 125 of pins 124, 224, and 324 can be press-fitted (see, for example, see...). Figure 8 In other examples, the second end of pins 124, 224, and 324 can be welded (see weld 150) to armatures 119, 219, and 319 at mounting positions 160, 260, and 360 (see, for example, see...). Figure 9 For example, pins 124, 224, and 324 can be press-fitted into mounting positions 160, 260, and 360 using weld 150. In other examples, the second end 125 of pins 124, 224, and 324 can be fastened to armatures 119, 219, and 319 using fastener 152. Figure 10 The image shows a screw-type fastener 152a for securing pins 124, 224, 324 to armatures 119, 219, 319 at mounting positions 160, 260, 360. Figure 11 The image shows a set screw type fastener 152a for securing pins 124, 224, 324 to armatures 119, 219, 319 at mounting positions 160, 260, 360. Figure 12 A cotter pin type fastener 152c is shown for securing pins 124, 224, 324 to armatures 119, 219, 319 at mounting positions 160, 260, 360.

[0061] The example of this disclosure can be described based on the following aspects.

[0062] Aspect 1. A differential assembly comprising: a stator including an electromagnet; a gearbox configured to rotate relative to the stator; a differential gear set disposed within the gearbox, the differential gear set including a locking gear; and a locking device disposed at the gearbox. The locking device includes: a locking member, an armature, a biasing member, and a pin. The locking member is disposed within the gearbox. The locking member is movable relative to the locking gear between a locked position and an unlocked position. The armature is disposed outside the gearbox. The armature is axially movable relative to the stator between a first position and a second position. The armature is configured to move to the second position when the electromagnet is energized. The biasing member is configured to bias the armature to the first position. The pin extends between the locking member and the armature. The pin is configured to maintain a separation distance between the locking member and the armature such that the locking device, as a unit, is axially movable relative to the gearbox. When the armature is in the first position, the locking member is in the unlocked position; and when the armature is in the second position, the locking member is in the locked position.

[0063] Aspect 2. Differential assembly of aspect 1, wherein the offset member is disposed outside the gearbox.

[0064] Aspect 3. Differential assembly of aspect 1, wherein the offset member is disposed within the gearbox.

[0065] Aspect 4. Differential assembly of aspect 1, wherein the locking member includes a locking ring having radial teeth.

[0066] Aspect 5. Differential assembly of aspect 1, wherein the locking member includes a locking plate having axial teeth.

[0067] Aspect 6. Differential assembly of any aspect of aspects 1-5, wherein the travel of the locking device is limited so as to provide clearance between the armature and the stator when the armature is in the second position.

[0068] Aspect 7. The differential assembly of any of aspects 1-6, wherein the armature includes a first mounting position configured to receive a first end of a pin; and wherein the locking member includes a second mounting position configured to receive a locking member.

[0069] Aspect 8. Differential assembly of aspect 7, wherein the first mounting position includes threads.

[0070] The differential assembly of aspect 9.7, wherein the first end of the pin is press-fitted at the first mounting position.

[0071] The differential assembly of aspect 10.7, wherein the first end of the pin is welded to the armature at the mounting position.

[0072] Aspect 11. Differential assembly of aspect 7, wherein the first end of the pin is held in a first mounting position by a fastener.

[0073] Aspect 12. Differential assembly of aspect 11, wherein the fasteners include horizontal screws.

[0074] Aspect 13. Differential assembly of aspect 11, wherein the fasteners include set screws.

[0075] Aspect 14. Differential assembly of aspect 11, wherein fasteners include cotter pins.

[0076] Aspect 15. Differential assembly of any aspect of aspects 1-15, wherein the pin is one of a plurality of pins extending between the locking member and the armature.

[0077] Aspect 16. A method of operating a locking differential, comprising: energizing an electromagnet to attract an iron armature from a first position to a second position against a biasing force; and moving the locking plate and the armature synchronously by pulling a pin connecting the locking plate and the armature, thereby moving the locking plate from an unlocked position to a locked position.

[0078] Aspect 17. The method of aspect 16 further includes de-energizing the electromagnet so that the bias force can move the armature back to the first position.

[0079] Aspect 18. A locking device for locking a differential, the locking device comprising: a locking plate movable relative to a locking gear of the differential between a locked position and an unlocked position, the locking plate engaging with the locking gear in the locked position to rotatably fix the locking plate and the locking gear together, the locking plate being rotatable relative to the locking gear in the unlocked position; an armature axially movable between a first position and a second position, the armature being biased in the first position and the armature being made of an ferrous material; and a pin extending between opposing first and second ends, the first end of the pin being axially fixed to the locking plate and the second end of the pin being axially fixed to the armature.

[0080] Aspect 19. Locking device of aspect 18, wherein the first end of the pin is clamped to the locking plate, and the second end of the pin is threaded to the armature.

[0081] The locking device of any aspect of aspects 20.18-19 further includes a stator that holds an electromagnet configured to move an armature to a second position when the electromagnet is energized, wherein the armature is biased to a first position by a biasing member disposed on the side of the armature opposite to the pin.

[0082] Aspect 21. A differential assembly comprising: a stator including an electromagnet; a gearbox configured to rotate relative to the stator; a differential gear set disposed within the gearbox, the differential gear set including a locking gear; a locking device mounted at the gearbox, the locking device comprising: a locking ring disposed within the gearbox, the locking ring being movable relative to the locking gear between a locked position and an unlocked position; and an armature disposed outside the gearbox, the armature being configured to rotate with the gearbox relative to the stator, the armature being movable relative to the stator in a first position. The armature is axially movable between a first position and a second position, wherein the armature is configured to move to the second position when the electromagnet is energized; a biasing member disposed between the stator and the armature to bias the armature to a first position; and a pin extending between the locking ring and the armature, the pin being configured to maintain a separation distance between the locking ring and the armature such that the locking device moves axially relative to the gearbox as a unit, wherein the locking ring is in an unlocked position when the armature is in the first position; and the locking ring is in a locked position when the armature is in the second position.

[0083] Aspect 22. Differential assembly of aspect 1, wherein the offset member is disposed outside the gearbox.

[0084] Aspect 23. The differential assembly of aspect 1 further includes a bushing disposed between the offset member and the stator.

[0085] Aspect 24. Differential assembly of aspect 1, wherein the biasing member includes a wave spring.

[0086] Aspect 25. Differential assembly of any aspect of aspects 1-4, wherein the travel of the locking device is limited so as to provide clearance between the armature and the stator when the armature is in the second position.

[0087] Aspect 26. Differential assembly of any aspect of aspects 1-5, wherein one of the armatures includes a mounting position configured to receive the first end of the pin.

[0088] Aspect 27. Differential assembly of aspect 6, wherein the mounting position includes threads.

[0089] Aspect 28. Differential assembly of aspect 6, wherein a mounting position defines an orifice into which a first end of a pin can be press-fitted.

[0090] Aspect 29. Differential assembly of aspect 6, wherein the first end of the pin is welded to the armature at the mounting position.

[0091] The differential assembly of aspect 30. aspect 6, wherein the first end of the pin is held in the mounting position by a fastener.

[0092] Aspect 31. Differential assembly of aspect 10, wherein the fasteners include horizontal screws.

[0093] Aspect 32. Differential assembly of aspect 10, wherein the fasteners include set screws.

[0094] Aspect 33. Differential assembly of aspect 10, wherein the fasteners include cotter pins.

[0095] Aspect 34. Differential assembly of aspect 1, wherein the second end of the pin is clamped to a locking ring.

[0096] Aspect 35. Differential assembly of any aspect of aspects 1-14, wherein the pin is one of a plurality of pins extending between the locking ring and the armature.

[0097] Having described the preferred aspects and embodiments of this disclosure, modifications and equivalents to the disclosed concepts will readily occur to those skilled in the art. However, such modifications and equivalents are intended to be included within the scope of the claims appended herein.

Claims

1. A differential assembly, comprising: Including the stator of the electromagnet; A gearbox configured to rotate relative to the stator; The differential gear set disposed within the gearbox includes a locking gear; A locking device is provided at the gearbox, the locking device comprising: A locking member is disposed within the gearbox, the locking member being movable relative to the locking gear between a locked position and an unlocked position; An armature disposed outside the gearbox is axially movable relative to the stator between a first position and a second position, the armature being configured to move to the second position when the electromagnet is energized; A biasing member configured to bias the armature to the first position; and A pin extending between the locking member and the armature, the pin being configured to maintain a separation distance between the locking member and the armature, such that the locking device moves axially as a unit relative to the gearbox, wherein the locking member is in the unlocked position when the armature is in the first position, and in the locked position when the armature is in the second position.

2. The differential assembly as claimed in claim 1, wherein, The biasing member is disposed outside the gearbox.

3. The differential assembly as claimed in claim 1, wherein, The biasing member is disposed within the gearbox.

4. The differential assembly as claimed in claim 1, wherein, The locking member includes a locking ring with radial teeth.

5. The differential assembly as claimed in claim 1, wherein, The locking member includes a locking plate with axial teeth.

6. The differential assembly as claimed in any one of claims 1-5, wherein, The gearbox defines a stop to limit the travel of the locking device, so as to provide a gap between the armature and the stator when the armature is in the second position.

7. The differential assembly as claimed in any one of claims 1-6, wherein, The armature includes a first mounting position configured to receive a first end of the pin; and wherein the locking member includes a second mounting position configured to receive the locking member.

8. The differential assembly of claim 7, wherein, The first mounting position includes threads.

9. The differential assembly of claim 7, wherein, The first end of the pin is press-fitted into the first mounting position.

10. The differential assembly of claim 7, wherein, The first end of the pin is welded to the armature at the mounting position.

11. The differential assembly of claim 7, wherein, The first end of the pin is held in the first mounting position using a fastener.

12. The differential assembly of claim 11, wherein, The fasteners include horizontal screws.

13. The differential assembly of claim 11, wherein, The fasteners include set screws.

14. The differential assembly of claim 11, wherein, The fasteners include cotter pins.

15. The differential assembly as claimed in any one of claims 1-15, wherein, The pin is one of a plurality of pins extending between the locking member and the armature.

16. A method of operating a locking differential, comprising: The electromagnet is energized to overcome the bias force and attract the armature from the first position to the second position, the armature being rotatable relative to the electromagnet; as well as By pulling the pin connecting the locking member and the armature, the locking member moves synchronously with the armature, thereby moving the locking member from the unlocked position to the locked position.

17. The method of claim 16, further comprising de-energizing the electromagnet so that the bias force can move the armature back to the first position.

18. A locking device for a locking differential having a locking gear, the locking device comprising: A locking member is movable relative to the locking gear of the locking differential between a locked position and an unlocked position. When in the locked position, the locking member engages with the locking gear to rotatably fix the locking plate and the locking gear together. When in the unlocked position, the locking member is rotatable relative to the locking gear. An armature capable of axial movement between a first position and a second position, the armature being biased to the first position, and the armature being made of a magnetizable material; and A pin extends between opposing first and second ends, the first end of the pin being axially fixed to the locking member, and the second end of the pin being axially fixed to the armature.

19. The locking device as claimed in claim 18, wherein, The first end of the pin is clamped to the locking member, and the second end of the pin is threaded to the armature.

20. The locking device of any one of claims 18-19, further comprising a stator for retaining the electromagnet, the electromagnet being configured to move the armature to the second position when the electromagnet is energized, wherein... The armature is biased to the first position by a biasing member disposed on the side of the armature opposite to the pin.

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