Axle assembly with torque sensor

Abstract

A torque sensing assembly of a differential of an axle assembly is shown in the present disclosure. The differential may include a differential housing portion, a drive gear shaft positioned within the differential housing portion, a ring gear, a gear carrier, differential pinions, a first side gear, a second side gear, a first bearing, a first bearing support, and the torque sensing assembly. The first bearing is coupled to the differential housing portion and is rotatable with the gear carrier. The first bearing support is coupled to the differential housing portion and is used to support the first bearing. The torque sensing assembly is coupled to the first bearing support and is operable to measure its strain caused by a separating force generated between the drive gear shaft and the ring gear.

Description

Technical Field

[0001] The present disclosure generally relates to an axle assembly and a torque sensing assembly applied to the axle assembly. Background Art

[0002] For a mechanical power transmission system, it is desirable to measure the axle torque applied to an axle assembly such as a front axle assembly, as it can affect the efficiency and lifespan of individual power transmission components and can provide information related to the operation of the vehicle and any attached tools or accessories for further use or processing. Summary of the Invention

[0003] An axle assembly coupled to a drive shaft is provided. The axle assembly may include a first axle unit, a second axle unit, a differential coupled to the first axle unit and the second axle unit, an axle housing, a drive pinion positioned within the axle housing, a ring gear, a gear carrier, differential pinions, a first side gear and a second side gear, a first axle shaft, a second axle shaft, a first bearing, a first bearing support, and a torque sensing assembly. The ring gear engages with the drive pinion and is driven by the drive pinion to rotate. The gear carrier is attached to the ring gear and rotates with the ring gear. The differential pinions are coupled to the gear carrier and are operable to rotate with the ring gear and to self-rotate about a differential pinion axis. The first side gear and the second side gear respectively engage with the differential pinions and are driven by the differential pinions. The first axle shaft is coupled to the first side gear and rotates with the first side gear. The second axle shaft is coupled to the second side gear and rotates with the second side gear. The first bearing is coupled to the axle housing and is rotatable with the gear carrier. The first bearing support is coupled to the axle housing and is used to support the first bearing. The torque sensing assembly is coupled to at least one of the axle housing and the first bearing support and is operable to measure its strain caused by a separating force generated between the drive pinion and the ring gear.

[0004] In one aspect of the present disclosure, the torque sensing assembly includes a first strain gauge and a second strain gauge positioned on the first bearing support.

[0005] In one aspect of the present disclosure, an angle formed by a first radial direction from the center of the first bearing support towards the first strain gauge and a second radial direction from the center of the first bearing support towards the second strain gauge is less than 60 degrees.

[0006] In one aspect of the present disclosure, the axle assembly further includes a fastener positioned on the first bearing support. The first strain gauge, the fastener, and the second strain gauge are on an arc, and the first strain gauge and the second strain gauge are at the ends of the arc.

[0007] In one aspect of the present disclosure, the fastener is positioned in the middle of the arc.

[0008] In one aspect of the present disclosure, the distance between the first side gear and the ring gear is closer than the distance between the second side gear and the ring gear.

[0009] In one aspect of the present disclosure, the torque sensing assembly includes a third strain gauge that is coupled to a first housing portion of the first axle unit and is operable to measure the strain of the first housing portion when the first axle unit is in operation.

[0010] In one aspect of the present disclosure, the first bearing support protrudes with a first outer ring portion coupled to the outer ring of the first bearing.

[0011] In one aspect of the present disclosure, the axle housing includes a differential housing portion of the differential. The differential housing portion includes a first differential side plate to which the first bearing support is coupled.

[0012] In one aspect of the present disclosure, the first differential side plate includes a receiving hole extending in a direction from the surface of the differential housing portion toward the first bearing. The receiving hole is for receiving a fourth strain gauge that includes a strain gauge pin operable to measure the strain in the receiving hole.

[0013] In one aspect of the present disclosure, the fourth strain gauge includes a strain gauge fastener that couples the body of the fourth strain gauge to the differential housing portion to provide an axial preload relative to the body of the fourth strain gauge.

[0014] In one aspect of the present disclosure, the sensing portion of the body of the fourth strain gauge engages the bottom of the receiving hole to measure its strain and cooperates with the strain gauge fastener to provide the axial preload.

[0015] In one aspect of the present disclosure, the fourth strain gauge and the receiving hole are press-fitted.

[0016] In one aspect of the present disclosure, the fourth strain gauge includes an upper portion and a lower portion coupled to the upper portion. The lower portion has a smaller diameter than the upper portion and is operable to measure the strain in the receiving hole.

[0017] A differential of an axle assembly is provided. The differential may include a differential housing portion, a drive pinion shaft positioned within the differential housing portion, a ring gear, a gear carrier, differential pinions, a first side gear, a second side gear, a first bearing, a first bearing support, and a torque sensing assembly. The ring gear engages the drive pinion shaft and is driven by the drive pinion shaft to rotate. The gear carrier is attached to the ring gear and is configured to rotate with the ring gear. The differential pinions are coupled to the gear carrier and are operable to rotate with the ring gear and to rotate about a differential pinion axis. The first side gear and the second side gear respectively engage the differential pinions and are driven by the differential pinions. The first bearing is coupled to the differential housing portion and is rotatable with the gear carrier. The first bearing support is coupled to the differential housing portion and is configured to support the first bearing. The torque sensing assembly is coupled to the first bearing support and is operable to measure its strain caused by a separating force generated between the drive pinion shaft and the ring gear.

[0018] In one aspect of the present disclosure, the distance between the first side gear and the ring gear is closer than the distance between the second side gear and the ring gear.

[0019] A differential of an axle assembly is provided. The differential may include a differential housing portion, a drive pinion shaft positioned within the differential housing portion, a ring gear, a gear carrier, differential pinions, a first side gear, a second side gear, a first bearing, a first bearing support, and a torque sensing assembly. The ring gear engages the drive pinion shaft and is driven by the drive pinion shaft to rotate. The gear carrier is attached to the ring gear and is configured to rotate with the ring gear. The differential pinions are coupled to the gear carrier and are operable to rotate with the ring gear and to rotate about a differential pinion axis. The first side gear and the second side gear respectively engage the differential pinions and are driven by the differential pinions. The first bearing is coupled to the differential housing portion and is rotatable with the gear carrier. The first bearing support is coupled to the differential housing portion and is configured to support the first bearing. The torque sensing assembly is coupled to the differential housing portion and is operable to measure its strain caused by a separating force generated between the drive pinion shaft and the ring gear.

[0020] In one aspect of the present disclosure, the differential housing portion includes a first differential side plate, the first bearing support is coupled to the first differential side plate, and the first differential side plate includes a receiving hole extending in a direction from the surface of the differential housing portion toward the first bearing. The receiving hole is configured to receive the torque sensing assembly, and the torque sensing assembly includes a strain gauge pin operable to measure strain in the receiving hole.

[0021] Other features and aspects will become apparent by considering the detailed description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic perspective view of an axle assembly.

[0023] Figure 2 is a side view of the differential of the axle assembly with the first axle unit removed.

[0024] Figure 3 is Figure 1 an exploded cross-sectional perspective view of the axle assembly.

[0025] Figure 4 is Figure 1 an exploded cross-sectional view of the axle assembly.

[0026] Figure 5 is a front view of the first bearing support having Figure 3 and Figure 4 the first and second strain gauges shown in.

[0027] Figure 6 is a partial cross-sectional view of the axle assembly showing two of the third strain gauges in Figure 1 .

[0028] Figure 7A is a cross-sectional view of a fourth strain gauge having a strain gauge pin in one embodiment.

[0029] Figure 7B is Figure 7A an enlarged cross-sectional view of the fourth strain gauge.

[0030] Figure 8 is a cross-sectional view of a fourth strain gauge having a strain gauge pin in another embodiment.

[0031] Figure 9 is a schematic diagram illustrating a controller connecting the first, second, third, and fourth strain gauges located in different parts of the axle assembly. DETAILED DESCRIPTION

[0032] The present disclosure includes a torque sensing assembly having one or more strain gauges applied to a bearing support of a powertrain component (e.g., a differential). The differential can be an open (standard) differential or a limited slip differential. The strain gauges detect strain on the bearing support and / or other parts of the powertrain, and such values can be used by a controller to calculate the torque of a drive shaft (e.g., a front axle drive shaft) or another component because the strain values detected from a particular location of the bearing support or other locations of the axle housing can have a positive correlation with the torque of the drive shaft (axle input torque). Specifically, the strain and torque can be a substantially linear relationship.

[0033] Due to the geometry of the front axle drive shaft having a drive pinion shaft and a ring gear, a gear carrier, (multiple) differential pinion gears (planetary gears) attached to the gear carrier (two in this embodiment), (multiple) differential side gears (two in this embodiment), a first bearing, a bearing support, etc., the (multiple) strain gauges of the torque sensing assembly detect strain caused by a separating load / force. The separating load is caused by the engagement (or reaction force) between the drive pinion shaft and the ring gear. The detailed structure is described below.

[0034] As Figures 1 to 3 and Figure 9 shown, work vehicle 99 includes axle assembly 10. Work vehicle 99 can include, but is not limited to, agricultural equipment (e.g., combine harvester, tractor, harvester, loader), or construction equipment (e.g., backhoe, dump truck, bulldozer, excavator, motor grader, scraper), or forestry equipment (e.g., feller buncher and skidder). Work vehicle 99 can include any other vehicle having one or more of the powertrain components described herein. In the present disclosure, as Figures 1 to 4The axle assembly 10 shown is a front axle assembly 10, but in another embodiment, it could be a rear axle assembly or other axle assembly. In another embodiment, the axle assembly 10 can be mounted at front and rear positions, i.e., four-wheel drive. The (front) axle assembly 10 includes an axle housing 12. The front axle assembly 10 can include a first axle unit 16, a second axle unit 18, and a differential 20 coupled between the first axle unit 16 and the second axle unit 18 via a bolt 19. The first axle unit 16 has a first axle shaft 162, and the second axle unit 18 has a second axle shaft 182. The first axle shaft 162 and the second axle shaft 182 are respectively coupled to a part of the ground engaging unit, e.g., a rim (not shown). The axle housing 12 of the axle assembly 10 includes a differential housing portion 122 of the differential 20, a first housing portion 124 of the first axle unit 16, and a second housing portion 126 of the second axle unit 18. The axle housing 12 is operable to receive variable power transmission system components, such as a differential case, gears, shafts, to be described later.

[0035] As Figure 3 and Figure 4 shown, the differential 20 coupled to a drive shaft (not shown) can include, but is not limited to, the axle housing 12, a drive pinion shaft 24, a ring gear 26, a differential case (gear carrier) 28, differential pinions (gears) 30, a first side gear 32, a second side gear 34, a first bearing 36, a first bearing support 38, a second bearing 40, and a second bearing support 42. The number of the foregoing elements is illustrated only for illustrative purposes in the embodiment. The drive pinion shaft 24 is generally coupled to the (front axle) drive shaft (not shown) via a universal joint 44 (as Figure 1 shown). As Figure 3 shown, the drive pinion shaft 24 is positioned within the axle housing 12. The ring gear 26 engages (meshes) with the drive pinion shaft (pinion assembly) 24 and is driven by the drive pinion shaft 24 to rotate. The ring gear 26 is a spiral bevel ring gear. The gear carrier 28 is attached to the ring gear 26 so as to rotate with the ring gear 26. In this embodiment, the gear carrier 28 is fixed to the ring gear 26 via a bolt 46. Within the gear carrier 28, two differential pins 31, each of which holds a pair of differential pinions 30 (in Figure 3Only one of each pair of differential pinions 30 is shown (differential pinion 30), such that the differential pinions 30 can rotate together with the ring gear 26. Additionally, the differential pinions 30 can rotate about their own differential pinion axes. When the differential pinions 30 rotate and / or rotate about their own axes, they engage or ride over the first side gear 32 and / or the second side gear 34, and thus the first side gear 32 and the second side gear 34 (differential side gears) can rotate independently of the gear carrier 28. In this regard, when the work vehicle 99 having the differential 20 turns left or right, one of the first side gear 32 or the second side gear 34 can ensure that the outer wheel or other external ground engaging unit rotates faster than the inner wheel or other internal ground engaging unit. Power (or torque from the front axle drive shaft) can be transmitted through the drive gear shaft 24, the ring gear 26, the gear carrier 28 (and the clutch plate 48 inside the gear carrier 28), the differential pinions 30, the first side gear 32 and / or the second side gear 34, and ultimately transmitted to the first axle unit 16 coupled to the first side gear 32 and / or the second axle unit 18 coupled to the second side gear 34. In this embodiment, the distance between the first side gear 32 and the ring gear 26 in the lateral direction is closer than the distance between the second side gear 34 and the ring gear 26 in the lateral direction.

[0036] As Figure 3 and Figure 4 shown in, the first bearing 36 and the second bearing 40 are applied on different sides of the gear carrier 28. The distance between the first bearing 36 and the ring gear 26 in the lateral direction is closer than the distance between the second bearing 40 and the ring gear 26 in the lateral direction. The first side 281 of the gear carrier 28 projects a first inner ring portion 282 (towards the first wheel, not shown), and the second side 285 of the gear carrier projects a second inner ring portion 286 (towards the second wheel, not shown). Regarding the first bearing 36, as Figure 4 shown in, it has a first inner race 362, a first outer race 364 (first bearing cup), and rolling elements 366 (such as rollers) between the first inner race 362 and the first outer race 364. The first inner race 362 is coupled to the first inner ring portion 282 and is configured to rotate together with the gear carrier 28. The rolling elements 366 are coupled to the first inner race 362 and are configured to roll in response to the rotation of the first inner race 362. The first outer race 364 relative to which the rolling elements 366 roll is fixed to the first bearing support 38 (sleeve). The first bearing support 38 (sleeve) is coupled to the differential housing portion 122 of the axle housing 12 and is configured to support the first bearing 36. As Figure 4As shown, the body of the first bearing support 38 is positioned on the left portion of the first bearing 36 to prevent the first bearing 36 from shifting out of the differential 20. The differential housing portion 122 includes a first differential side plate 121 and a second differential side plate 129, and the pinion carrier 28 is positioned therebetween. The first bearing support 38 is coupled to the first differential side plate 121 by a fastener 382, which in this embodiment is a bolt. In this embodiment, the first bearing support 38 projects a first outer ring portion 384 coupled to the first outer ring 364 and parallel to the first inner ring portion 282 of the pinion carrier 28. The first bearing 36 is sandwiched between the first inner ring portion 282 of the pinion carrier 28 and the first outer ring portion 384 of the first bearing support 38. The first differential side plate 121 includes an aperture 123. The first outer ring portion 384 of the first bearing support 38 and the aperture 123 are press-fitted.

[0037] In this embodiment, the torque sensing assembly 60 is applied to the first bearing support 38. However, in another embodiment, a torque sensing assembly (not shown) may be applied to the second bearing support 42. In another variation, one or more torque sensing assemblies 60 may be mounted on both the first bearing support 38 and the second bearing support 42. As shown in the following embodiments, the strain gauges of the torque sensing assembly 60 may be located at or in a bearing receiving element, such as a (plural) bearing support member that deflects under strain when loaded. Thus, these strain gauges generate strain signals caused by gear separating forces proportional to the powertrain torque. Since the strain gauges may be positioned on or near the bearings and bearing supports (where the gear separating forces of interest may be located), the strain measurements are less affected by vehicle structural loads.

[0038] Reference Figure 4 and Figure 5 , in this embodiment, the torque sensing assembly 60 includes a first strain gauge 62 and a second strain gauge 64 positioned on the first bearing support 38. For example, a first radial direction from the center of the first bearing support 38 toward the first strain gauge 62 and a second radial direction from the center of the first bearing support 38 toward the second strain gauge 64 form an angle θ less than or equal to 60 degrees. In another embodiment, the angle may be a different angle. As Figure 5As shown, in this embodiment, the first bearing support 38 has a stub axle hole 381 through which the first axle 162 passes. The first bearing support 38 may have an inner support portion 385 adjacent to the stub axle hole 381, and may have an outer support portion 387 which is a flange or platform of the inner support portion 385. A step is formed between the inner support portion 385 and the outer support portion 387. In this embodiment, the outer support portion 387 of the first bearing support 38 includes a plurality of holes 386. As previously mentioned, a plurality of fasteners 382 connect the first bearing support 38 to the first differential side plate 121 of the differential housing portion 122 through the holes 386 of the outer support portion 387. In this embodiment, the first strain gauge 62 and the second strain gauge 64 are positioned on the outer support portion 387 of the first bearing support 38. One of the fasteners 382 is positioned between the first strain gauge 62 and the second strain gauge 64. The first strain gauge 62, the fastener 382, and the second strain gauge 64 are on an arc. The first strain gauge 62 and the second strain gauge 64 are at the ends of the arc. The fastener is positioned in the middle of the arc, but in another embodiment, it does not have to be in the middle.

[0039] In a variant, there is more than one fastener aligned in the same arc between the first strain gauge 62 and the second strain gauge 64.

[0040] In a variant, only one strain gauge or more than two strain gauges are applied on the outer support portion and / or the inner support portion. In a variant, it is not necessary or not all the strain gauges need to be positioned on the same arc.

[0041] In this embodiment, the holes 386 on the outer support portion 387 of the first bearing support 38 are equally spaced. For the purpose of strain measurement, in another embodiment, the distances of the holes 386 may be different. For example, the hole (if there is only one) between the first strain gauge 62 and the second strain gauge 64 is defined as the unique hole. The distance between adjacent regular holes is longer than the distance between two adjacent regular holes (not shown). For another embodiment, there is no hole between the first strain gauge 62 and the second strain gauge 64, but the distance between the hole adjacent to the first strain gauge 62 and another hole adjacent to the second strain gauge 64 is longer than the distance between two other adjacent regular holes. In a variant, the fastener (if there is only one) between the first strain gauge 62 and the second strain gauge 64 may be different from other fasteners, and the other fasteners may be smaller or more flexible; the hole corresponding to the fastener may correspond to the size of the fastener.

[0042] In another embodiment, the first bearing support 38 is connected to the first differential side plate 121 of the differential housing portion 122 in other ways.

[0043] In another embodiment, the first bearing support 38 may additionally include one or more different types of holes / apertures for receiving a torque sensor assembly 60, such as a first strain gauge 62 and a second strain gauge 64. Such holes may be blind holes or through-holes. The torque sensor assembly 60 (the first strain gauge 62 or the second strain gauge 64) may include a retainer attached to the wall of the hole. The retainer may be press-fitted into the hole. The torque sensor assembly may further include a sleeve corresponding to and attached to the inner surface of the retainer. One or more strain sensors are attached to the sleeve and are configured to detect strain in the first bearing support caused by the separating force between the drive gear shaft and the ring gear. Optionally, the sleeve is a flexible printed circuit board electrically coupled to the plurality of strain gauges via traces.

[0044] As Figure 3 and Figure 4 shown, when the drive gear shaft 24 rotates, a separating force F1 is generated due to the rotation of the (spiral bevel) drive gear shaft 24 and the ring gear 26. The resulting gear separating force Fr is transmitted to the first bearing support 38, and the magnitude of the separating force Fr may be proportional to the separating force F1 between the drive gear shaft 24 and the ring gear 26. The torque sensor assembly 60 (e.g., the first strain gauge 62 and / or the second strain gauge 64) thus detects the strain caused by the resulting gear force Fr. As Figure 9 shown, a controller 90 of a work vehicle 99 having an axial assembly 10 may receive strain signals from the torque sensor assembly 60 (e.g., the first strain gauge 62, the second strain gauge 64, the third strain gauge 66, and / or the fourth strain gauge 68) to calculate the axle input torque due to a geometry-based correlation. The third strain gauge 66 and the fourth strain gauge 68 will be introduced in the following description.

[0045] The number of the third strain gauges 66 may be one or more. Figure 1 and Figure 4 shows one third strain gauge 66; Figure 6 shows two third strain gauges 66. The one or more third strain gauges 66 are coupled to a first housing portion 124 of the first axle unit 16 and are operable to measure strain in the first housing portion 124 when the first axle unit 16 is in operation. As Figure 6 shown, due to the reaction of the traction force F2 from the tire / wheel and thus the squeezing force applied to the axle unit 16, the deflection in the first housing portion 124 may be proportional to the axle input torque. This deflection DL may be monitored by the third strain gauge 66. The resulting output of the third strain gauge 66 may be proportional to the axle input torque.

[0046] Referring to Figure 7A , Figure 7B and Figure 8, a fourth strain gauge 68 of the torque sensing assembly 60 is introduced. The first differential side plate 121 of the differential housing portion 122 includes a receiving hole 1212 (in Figure 8 , the receiving hole 1214) extending in the radial direction from the surface of the differential housing 122 towards the first bearing 36. The bottom 1213 of the receiving hole 1212 is adjacent to the orifice 123 of the first differential side plate 121. The receiving hole (1212 or 1214) is configured to receive the fourth strain gauge 68, and the fourth strain gauge 68 includes a strain gauge pin (682 or 686) operable to measure the strain in the receiving hole (1212 or 1214) of the first differential side plate 121 caused by the separating force F1. Since the first outer ring portion 384 of the first bearing support 38 abuts the orifice 123 (press fit), and the outer support portion 387 of the first bearing support 38 overlaps the lower portion of the receiving hole (1212, 1214) in the radial direction with respect to the center of the axle hole 381 of the first bearing support 38, the obtained force can be easily transmitted to the receiving hole (1212, 1214), resulting in its deflection, and facilitating the measurement result of the strain detected by the fourth strain gauge 68.

[0047] In one embodiment, as shown in Figure 2 , Figure 7A and Figure 7B , the fourth strain gauge 68 includes a strain gauge pin 682. The strain gauge pin 682 includes a strain gauge fastener 683 that couples the body of the strain gauge pin 682 to the differential housing portion 122. The strain gauge fastener 683 may include a threaded feature that couples to the threaded upper portion of the receiving hole 1212 and a nut 684 that couples to the threaded feature. The sensing portion 685 of the strain gauge pin 682 engages the bottom 1213 of the receiving hole 1212 to measure its strain. In this embodiment, the sensing portion 685 is the bottom of the body of the strain gauge pin 682. The sensing portion 685 cooperates with the strain gauge fastener 683 to provide an axial preload relative to the body of the strain gauge pin 682. The axial preload may be uniform and adjustable by the nut 684 of the strain gauge fastener 683. The uniform axial preload on the strain gauge pin 682 can ensure that the strain gauge pin 682 accurately measures the strain.

[0048] Referring to Figure 8, the fourth strain gauge 68 includes a strain gauge pin 686. The strain gauge pin 686 and the receiving hole 1214 are press-fitted, which can also provide an axial preload. The configuration of the receiving hole 1214 corresponds to the configuration of the strain gauge pin 686. The strain gauge pin 686 includes an upper portion 687 and a lower portion 688 coupled to the upper portion 687. The lower portion 688 has a smaller diameter than the upper portion 687 and is operable to measure the strain in the receiving hole 1212. Note that the lower portion 688 of the strain gauge pin 686 is press-fitted into the lower portion of the receiving hole 1212, and the lower portion of the receiving hole 1212 is the effective area of the differential housing portion 122 for strain measurement.

[0049] As Figure 9 shown, the first strain gauge 62, the second strain gauge 64, the third strain gauge 66, and the fourth strain gauge 68 measure the strain on the first bearing support 38, the first housing portion, and / or the first differential side plate 121, and transmit the signal(s) indicating the strain generated by the separating force F1 or the operation of the first axle unit 16 to the controller 90 of the work vehicle 99 to calculate the torque. The relationship between the axle input torque, the deflection of the first bearing support and its strain, and the deflection of the axle housing can be defined mathematically based on the dimensions of the gears, the tire size, and the stiffness of the axle components. The controller(s) 90 can include, but are not limited to, an engine control unit (ECU), a transmission control unit (TCU), a chassis control unit (CCU), and a signal controller (analyzer) coupled to the strain gauges 62, 64, 66, 68. The signal controller communicates with the ECU, TCU, CCU via a controller area network (not shown). The CAN frame is typically placed on the CAN bus, which includes a first signal-carrying line and a second signal-carrying line. The controller(s) 90 are connected to the first and second signal-carrying lines. The controller(s) 90 can be coupled to or include a memory operable to store data.

[0050] The measurement of torque can be used for different purposes. For example, torque information can be received by the controller 90, and if there is an excessive torque load, the controller 90 can reduce the engine speed to ensure the efficiency and lifespan of the power transmission unit. The direct powertrain torque measurement results can be used for engine control. By more directly sensing the powertrain torque, the expected engine load can be electronically transmitted to the ECU, so that the engine can be appropriately fueled (power management) before the mechanical load is transmitted through the powertrain components and drags down the engine. The direct powertrain torque measurement results can be used for adaptive shift control (ASC) in the powertrain control unit to shift gears in an appropriate manner for different slopes of the ground surface. The direct powertrain strain measurement can also be used for powertrain prediction. The powertrain strain signal can be monitored and compared with the normal powertrain signal. A deviation from this normal signal may indicate damage suffered by the gears and bearings. A continuous deviation from the normal value can be used to warn the operator or the dealer of an impending powertrain failure.

[0051] Without in any way limiting the scope, interpretation, or application of the claims that appear hereinafter, a technical effect of one or more of the exemplary embodiments disclosed herein is to measure the strain from a bearing support or an axle housing, where other loads (e.g., vehicle structure loads) do not interfere with the measurement results.

[0052] Although the exemplary embodiments of the present disclosure have been described above, these descriptions should not be taken in a limiting sense. Rather, other changes and modifications can be made without departing from the scope and spirit of the present disclosure as defined by the appended claims.

Claims

1. An axle assembly (10) coupled to a drive shaft, the axle assembly comprising: A first axle unit (16); A second axle unit (18); A differential (20) disposed between the first axle unit (16) and the second axle unit (18) and coupled in parallel to the first axle unit (16) and the second axle unit (18); An axle housing (12); A drive gear shaft (24) positioned within the axle housing (12); A ring gear (26) engaged with the drive gear shaft (24) and driven by the drive gear shaft (24) to rotate; A gear carrier (28) attached to the ring gear (26) and configured to rotate with the ring gear (26); Differential pinions (30) coupled to the gear carrier (28), operable to rotate with the ring gear (26) and self-rotate about a differential pinion axis; A first side gear (32) and a second side gear (34) respectively engaged with the differential pinions (30) and driven by the differential pinions (30); A first axle (162) coupled to the first side gear (32) and rotating with the first side gear (32); A second axle (182) coupled to the second side gear (34) and rotating with the second side gear (34); A first bearing (36) coupled to the axle housing (12) and capable of rotating with the gear carrier (28); A first bearing support (38) coupled to the axle housing (12) and configured to support the first bearing (36); A torque sensing assembly (60) coupled to at least one of the axle housing (12) and the first bearing support (38), operable to measure strain in the at least one of the axle housing (12) and the first bearing support (38) caused by a separating force generated between the drive gear shaft (24) and the ring gear (26), wherein the axle housing (12) includes a differential housing portion (122) of the differential (20), and the differential housing portion (122) includes a first differential side plate (121) to which the first bearing support (38) is coupled, wherein the first differential side plate (121) includes receiving holes (1212, 1214) extending in a direction from a surface of the differential housing portion (122) toward the first bearing (36), and the receiving holes (1212, 1214) are configured to receive a fourth strain gauge (68) including strain gauge pins (682, 686) operable to measure strain in the receiving holes (1212, 1214).

2. The axle assembly (10) according to claim 1, wherein, The torque sensing assembly (60) includes a first strain gauge (62) and a second strain gauge (64) positioned on the first bearing support (38).

3. The axle assembly (10) according to claim 2, wherein, A first radial direction from the center of the first bearing support (38) towards the first strain gauge (62) and a second radial direction from the center of the first bearing support (38) towards the second strain gauge (64) form an angle of less than 60 degrees.

4. The axle assembly (10) according to claim 2, further comprising a fastener (382) positioned on the first bearing support (38), and wherein, The first strain gauge (62), the fastener (382), and the second strain gauge (64) are on an arc, and the first strain gauge (62) and the second strain gauge (64) are at the ends of the arc.

5. The axle assembly (10) according to claim 1, wherein, The distance between the first side gear (32) and the ring gear (26) is closer than the distance between the second side gear (34) and the ring gear (26).

6. The axle assembly (10) according to claim 1, wherein, The torque sensing assembly (60) includes a third strain gauge (66) that is coupled to a first housing portion (124) of the first axle unit (16) and is operable to measure the strain of the first housing portion (124) when the first axle unit (16) is in operation.

7. The axle assembly (10) according to claim 1, wherein, The fourth strain gauge (68) includes a strain gauge fastener (683) that couples the body of the fourth strain gauge (68) to the differential housing portion (122) to provide an axial preload relative to the body of the fourth strain gauge (68).

8. The axle assembly (10) according to claim 7, wherein, A sensing portion (685) of the body of the fourth strain gauge (68) engages the bottom (1213) of the receiving hole (1212) to measure the strain of the bottom (1213) of the receiving hole (1212) and cooperates with the strain gauge fastener (683) to provide the axial preload.

9. The axle assembly (10) according to claim 1, wherein, The fourth strain gauge (68) and the receiving hole (1214) are press-fitted.

10. The axle assembly (10) according to claim 9, wherein, The fourth strain gauge (68) includes an upper portion (687) and a lower portion (688) coupled to the upper portion (687), and the lower portion (688) has a smaller diameter than the upper portion (687) and is operable to measure the strain in the receiving hole (1214).

11. A differential (20) of an axle assembly (10), comprising: A differential housing portion (122); A drive pinion shaft (24) positioned within the differential housing portion (122); A ring gear (26) that engages the drive pinion shaft (24) and is driven by the drive pinion shaft (24) to rotate; A gear carrier (28) that is attached to the ring gear (26) and is configured to rotate with the ring gear (26); Differential pinions (30) that are coupled to the gear carrier (28), are operable to rotate with the ring gear (26), and self-rotate about a differential pinion axis; A first side gear (32) and a second side gear (34), the first side gear and the second side gear being respectively engaged with and driven by the differential pinion gears (30); A first bearing (36), the first bearing being coupled to the differential case portion (122) and being rotatable together with the pinion carrier (28); A first bearing support (38), the first bearing support being coupled to the differential case portion (122) and being configured to support the first bearing (36); A torque sensing assembly (60), the torque sensing assembly being coupled to the differential case portion (122) and being operable to measure the strain in the differential case portion (122) caused by the separating force generated between the drive pinion shaft (24) and the ring gear (26); wherein the differential case portion (122) includes a first differential side plate (121) to which the first bearing support (38) is coupled; wherein the first differential side plate (121) includes receiving holes (1212, 1214) extending in a direction from the surface of the differential case portion (122) toward the first bearing (36), and the receiving holes (1212, 1214) are configured to receive the torque sensing assembly (60), the torque sensing assembly (60) including strain gauge pins (682, 686) operable to measure the strain in the receiving holes (1212, 1214).

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