DIFFERENTIAL ASSEMBLY OIL MANAGEMENT INSERT

Abstract

A motor vehicle drive axle (16) comprising: a drive axle housing (24) which defines: a differential gear set cavity (28); a shaft bore (30) having first (32-1) and second (32-2) bearing pockets and an oil cavity (34) disposed between the first and second bearing pockets; an oil supply passage (36-1) configured to supply oil from the differential gear set cavity (28) into the oil cavity (34); and an oil return passage (36-2) configured to return oil from the oil cavity (34) to the differential gear set cavity (28); a differential gear set (26) disposed within the differential gear set cavity (28); an input shaft (38) extending through the shaft bore (30) into the differential gear set cavity (28), operatively connected to the differential gear set (26) and configured to transmit drive torque to the differential gear set (26); a first bearing (40-1) disposed in the first bearing pocket (32-1) and configured to support the input shaft (38) relative to the drive axle housing (24); a second bearing (40-2) disposed in the second bearing pocket (32-2) between the first bearing (40-1) and the differential gear set cavity (28) and configured to support the input shaft (38) relative to the drive axle housing (24); and a lubrication regulating insert (42) arranged inside the oil cavity (34) and defining: a first lubrication channel (44-1) configured to conduct oil from the oil supply channel (36-1) to the first bearing (40-1); and a second lubrication channel (44-2) configured to conduct oil from the oil supply channel (36-1) to the second bearing (40-2), wherein the lubrication regulating insert (42) additionally defines an oil dam (48) configured to maintain a preset oil level within the shaft bore (30) at the first bearing (40-1) and thereby minimize oil starvation of the first bearing (40-1), wherein the lubrication regulating insert (42) additionally defines an oil collection pan (56) configured to be aligned with the oil supply channel (36-1) of the drive axle housing (24), and wherein both the first lubrication channel (44-1) and the second lubrication channel (44-2) are in fluid communication with the oil collection pan (56), wherein the first lubrication channel (44-1) is arranged at an angle to the second lubrication channel (44-2), wherein the lubrication regulating insert (42) is constructed from a polymer composite material, wherein the drive axle housing (24) further defines a first feed channel (58-1) and a second feed channel (58-2) by casting, the first feed channel (58-1) being configured that it conducts oil from the first lubrication channel (44-1) to the first bearing (40-1), while the second supply channel (58-2) is configured to conduct oil from the second lubrication channel (44-2) to the second bearing (40-2), wherein the lubrication regulating insert (42) has a projection (60), wherein the projection (60) is configured to engage and be located in a groove cast into the drive axle housing (24), the projection (60) being provided to index the lubrication regulating insert (42) in the shaft bore (30) to thereby align the oil collection groove (56) with the oil supply channel (36-1), a lubricant outlet opening (54) with the oil return channel (36-2) and the first and second supply channels (58-1, 58-2) with the respective first and second lubricant channels (44-1, 44-2).

Description

INITIATIONThe disclosure relates to an oil management insert for a motor vehicle differential assembly.Motor vehicles may be equipped with either two-wheel drive, i.e., a single drive or drive axle, or multiple drive axles. Both types of vehicles may use a conventional powertrain in which a single motor is used to propel the vehicle, an electric powertrain in which an electric motor is used to propel the vehicle, or a hybrid powertrain in which two or more different energy sources, such as an internal combustion engine and an electric motor, are used to accomplish the same task. Motor vehicles may also use multiple independent energy sources, such as an internal combustion engine and an electric motor, to drive individual vehicle drive axles independently of one another.Each driven axle typically includes a final drive assembly having a differential that allows the driven wheels of the opposite sides, i.e., the left and right sides, to rotate at different speeds as the vehicle turns. In particular, the differential allows the driven wheel that travels around the outside of the turn to roll more and more rapidly than the driven wheel that travels around the inside of the turn while applying approximately the same torque to each of the driven wheels. An increase in the speed of one driven wheel is compensated for by a decrease in the speed of the other driven wheel, the average speed of the two driven wheels being equal to the input speed of the drive shaft which connects the power source to the differential. Internal supporting and rotating components of such driven axles generally require constant lubrication and cooling for reliable long term operation.JP 2009-041 590 A describes an adjusting device which can guide most or all of the oil from the oil supply passage between the two rolling bearings when the amount of oil introduced into the passage is small. However, when the introduced amount of oil is large, the device regulates the oil supply between the two rolling bearings.US 2011 / 0 064 344 A1 describes a bearing lubrication structure for a rotary shaft, comprising: a pair of bearings arranged at an axial distance from each other in a support housing to rotatably support a predetermined rotary shaft about its axis; and an oil supply port arranged on the support housing to supply lubricating oil for lubrication of the bearing between the two bearings, wherein a separator is arranged in the axial direction that receives the lubricating oil supplied from the oil supply port to prevent the lubricating oil from directly adhering to the rotary shaft. The separator is integrally attached to the support housing.JP 2011-179 544 A describes an apparatus comprising a drive pinion which is in engagement with a spur gear, and two tapered roller bearings for supporting the pinion. Between the bearings is a sleeve having two flanges and a connecting element made of stretchable materials which expand or contract according to temperature change.JP 2009-174 682 A describes a differential wherein a bevel gear shaft having a bevel gear fixed thereto is supported at both ends by tapered roller bearings. The lubricating oil in the oil reservoir of the differential case is lifted from a spur gear connected to the spur gear. The raised oil is stored in a reservoir tank above the bearings, the tank having front and rear outlet ports near the respective bearings.DESCRIPTIONIt is an object of the invention to counteract insufficient lubrication, overheating and excessive lubricant consumption of the bearings in a vehicle drive system. This object is achieved by the subject matter according to claim 1.A motor vehicle drive axle includes a drive axle housing. The drive axle housing defines a differential gear set cavity and a shaft bore having first and second bearing pockets and an oil cavity disposed between the first and second bearing pockets. The drive axle housing also defines a supply passage configured to supply oil from the differential gearset cavity into the oil cavity and a return passage configured to return oil from the oil cavity into the differential gearset cavity. The drive axle housing also includes a differential gear set disposed in the differential gear set cavity, and an input shaft extending through the shaft bore into the differential gear set cavity is operatively connected to the differential gear set and configured to transmit drive torque to the differential gear set.The drive axle housing additionally includes a first bearing disposed in the first bearing pocket and configured to support the input shaft relative to the drive axle housing. The drive axle housing also includes a second bearing disposed in the second bearing pocket between the first bearing and the differential gearset cavity and configured to support the input shaft relative to the drive axle housing. The drive axle housing additionally includes a lubrication regulating insert disposed within the oil cavity. The lubrication regulating insert defines a first lubrication passage configured to direct oil from the oil supply passage to the first bearing and a second lubrication passage configured to direct oil from the oil supply passage to the second bearing.The lubrication regulating insert also defines an oil dam configured to maintain a preset oil level in the shaft bore at the first bearing, thereby minimizing oil shortage of the first bearing.The lubrication regulator insert may be formed as a cylindrical shell concentrically disposed about a central axis.The oil dam may be defined by an annular flange that is arranged orthogonally to the cylindrical jacket and extends in the direction of the central axis.The lubrication regulating insert can additionally define a lubricant outlet opening which is in fluid communication with the oil return channel of the drive axle housing.The lubrication regulating insert additionally defines an oil collection sump configured to align with the supply passage of the drive axle housing. In such an embodiment, the first lubrication channel and the second lubrication channel may each be in fluid communication with the oil collection groove.The first lubrication channel may be disposed at an angle to the second lubrication channel.The lubrication regulating insert may be pushed into the oil cavity.The lubrication control insert may be made of a polymeric composite material or a metallic material.This may be either a stamped, cast or sintered component.A motor vehicle using such a drive axle is also disclosed.The above features and advantages, as well as other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiment(s) and best mode(s) for carrying out the described disclosure when considered in connection with the accompanying figures and the appended claims.BRIEF DESCRIPTION OF THE FIGURESFIG. 1 is a schematic illustration of a motor vehicle having a powertrain including a power source coupled to a transmission assembly operatively coupled to a drive axle via a drive shaft, in accordance with the disclosure. FIG. 2 is a schematic close-up partial cross-section of the drive axle shown in FIG. 1, showing, in particular, an input shaft supported in a differential case and a lubrication control insert disposed between the bearings, in accordance with the disclosure. FIG. 3 is a schematic close-up perspective view of the input shaft supported by bearings and the lubrication regulating insert disposed relative thereto, with the differential housing structure removed to better view details of the insert with respect to the arrangement of the bearings. FIG. 4 is a close-up schematic perspective view of the lubrication regulating insert disposed within the differential case with the input shaft and bearings removed for ease of viewing details of the insert and corresponding features of the differential case. FIG. 5 is a schematic close-up front view of an embodiment of the lubrication regulating insert shown in FIGS. 2-4 in accordance with the disclosure.DETAILED DESCRIPTIONReferring to the Figures, wherein like elements are designated by identical reference numerals throughout, FIGS. 1 and 2 show a wheeled motor vehicle 10. The vehicle 10 is generally disposed along a vehicle longitudinal axis X. As shown in FIG. 1, the vehicle 10 includes a power source 12 configured to generate a power source drive torque T, is coupled to a transmission assembly 13, and is operatively coupled to a drive axle 16 via a driveshaft 14. The drive axle 16 is in turn connected to the respective left and right wheels 18-1, 18-2 providing vehicle propulsion. Although a single power source 12 and a single drive axle 16 are illustrated, nothing excludes the vehicle 10 from using a combination of power sources and multiple drive axles for its propulsion. The particular road wheels 18- 1, 18- 2 receiving the drive torque T from the power source 12 to propel the vehicle 10 on a road surface 20 may be defined as "drive wheels.".As shown, the drive axle 16 is disposed substantially transversely to the vehicle longitudinal axis X such that the drive axle rotates individual first and second axle shafts 22- 1, 22- 2 to thereby rotate the respective first and second drive wheels 18- 1, 18- 2. In accordance with the present disclosure, the drive axle 16 includes a drive axle housing 24. the drive axle 16 also includes a differential gear set 26 having a pinion 27, although not shown in its entirety, the differential gear set 26 is typically a three shaft reduction gear having the characteristic that the speed of one shaft is the average of the speeds of the others or a fixed multiple of that average. The differential 26 is connected to the power source 12 via the input shaft 14 in order to absorb the drive torque T and distribute it to the axle shafts 22- 1 and 22- 2. In other words, the first axle shaft 22- 1 receives a portion of the drive torque T and transmits that portion of torque to the first drive wheel 18- 1, while the second axle shaft 22- 2 receives another portion of the torque T and transmits that other portion of torque to the second drive wheel 18- 2.As shown in FIG. 2, the drive axle housing 24 defines a differential gearset cavity 28 that also contains a main oil sump. The differential gearset 26 is disposed within the differential gearset cavity 28. The drive axle housing 24 also defines a shaft bore 30 that includes a first bearing pocket 32- 1 and a second bearing pocket 32- 2, and an oil cavity 34 disposed between the first and second bearing pockets. The drive axle housing 24 additionally defines a supply passage 36- 1 (shown in FIGS. 2 and 4 ) configured to supply differential oil from the differential gearset cavity 28 and its main sump into the oil cavity 34, and a return passage 36- 2 (shown in FIG. 4 ) configured to return oil from the oil cavity into the differential gearset cavity. An input shaft 38 extends through the shaft bore 30 into the differential gearset cavity 28 and is operatively connected to the differential gearset via the pinion 27. The input shaft 38 is designed specifically for transmitting the drive torque T to the differential gear set 26.The drive axle 16 also includes a first bearing 40- 1 disposed within the first bearing pocket 32- 1 and a second bearing 40- 2 disposed within the second bearing pocket 32- 2. As shown, the second bearing 40- 2 is disposed between the first bearing 40- 1 and the differential gearset cavity 28. The first bearing 40- 1 and the second bearing 40- 2 may be configured as helical or thrust bearings and are collectively configured to support the input shaft 38 relative to the drive axle housing 24. The drive axle 16 additionally includes a lubrication control insert 42 disposed and secured within the oil cavity 34. In particular, the lubrication regulating insert 42 may be press fit into the oil cavity 34. The lubrication control insert 42 may be made of a moldable high temperature polymeric composite or a deformable metallic material. The lubrication control insert 42 may be either a stamped, sintered, machined or molded component.As shown in FIG. 3 with respect to the X-Y-Z coordinate axes, the insert 42 defines a first lubrication passage 44- 1 configured to direct oil from the oil supply passage 36- 1 to the first bearing 40- 1. The insert 42 also defines a second lubrication passage 44- 2 configured to direct oil from the oil supply passage 36- 1 to the second bearing 40- 2. As shown, the lubrication control insert 42 may be shaped as a cylindrical shell 46 disposed substantially concentrically about a central axis X. As shown in FIGS. 2 and 3, the lubrication regulating insert 42 may additionally define an oil dam 48. The oil dam 48 is configured to maintain a preset level 50 and a preset amount of oil (shown in FIG. 2 ) in the shaft bore 30 at the first bearing 40- 1, thereby minimizing oil shortage of the bearing in question during operation of the vehicle 10 and the drive axle 16.Although not specifically shown, the drive axle 16 may be installed in the vehicle 10 for proper engagement and operation of the driveshaft 14 at a predefined angle with respect to the road surface 20. In such an application, the oil within the drive axle 16 has a general tendency to flow away from the first bearing 40- 1 and toward the second bearing 40- 2. As a result, the oil dam 48 may also prevent at least a portion of the oil from exiting the first bearing 40- 1 and flowing down the shaft bore 30. As shown in FIGS. 2 and 3, the oil dam 48 may be defined by an annular flange 52 that is disposed orthogonally with respect to the cylindrical shell 46 and extends toward the central axis X, thereby being configured such that the first bearing 40- 1 remains at least partially submerged in oil during operation of the drive axle 16.The lubrication regulating insert 42 may additionally define a lubricant outlet opening 54 (shown in FIGS. 4 and 5 ) in fluid communication with the oil return passage 36- 2 of the drive axle housing 24. When considering the lubrication regulating insert 42 in the Y-Z plane (shown in FIG. 3 ), the lubricant exit opening 54 may be arranged between 3 and 9 o'clock to allow an appropriate balance between an amount of oil held in the oil cavity 34 bounded by the insert 42, lubricating the second bearing 40- 2, and being recirculated to the main sump. In FIG. 4, the lubricant outlet opening 54 is positioned at about 6 o'clock, while in FIG. 5 a position of the lubricant outlet opening 54 between 4 and 5 o'clock is shown.The lubrication regulating insert 42 may also define an oil collection groove 56. The oil collecting groove 56 is disposed at about 12 o'clock (shown in FIG. 4 ) and is configured to be aligned with the supply passage 36- 1 of the drive axle housing 24. As shown, both the first lubrication passage 44- 1 and the second lubrication passage 44- 2 may be in fluid communication with the oil collection sump 56. As shown in FIG. 3, the first lubrication passage 44- 1 may be disposed at an angle θ with respect to the second lubrication passage 44- 2 on the same side of the lubrication regulation insert 42. Alternatively, the first lubrication passage 44- 1 and the second lubrication passage 44- 2 may be disposed on opposite sides of the lubrication regulating insert 42 as illustrated in FIG. 4.As shown in FIG. 4, the drive axle housing 24 may further define a first feed channel 58- 1 and a second feed channel 58- 2, for example, by casting and / or machining. The first supply passage 58- 1 is configured to direct oil from the first lubrication passage 44- 1 to the first bearing 40- 1, while the second supply passage 58- 2 is configured to direct oil from the second lubrication passage 44- 2 to the second bearing 40- 2. As seen in FIGS. 2-5, the lubrication regulating insert 42 may include a protrusion 60. The protrusion 60 may be configured to engage and be located within a groove (not shown) cast and / or machined into the drive axle housing 24. The protrusion 60 is provided to index the insert into the shaft bore 30 to thereby align the oil collection groove 56 with the supply passage 36- 1, the lubricant discharge port 54 with the return passage 36- 2, and the first and second supply passages 58- 1, 58- 2 with the respective first and second lubricant passages 44- 1, 44- 2.Overall, the lubrication regulating insert 42 is configured and disposed within the drive axle housing 24 to direct lubricating and cooling oil to the first and second bearings 40- 1, 40- 2. Due to the particular shape and arrangement of the lubrication regulating insert 42, an oil deficiency at the first bearing 40- 1 is to be minimized and the second bearing 40- 2 is to be supplied with oil in a metered manner during operation of the motor vehicle 10. In other words, when the driving torque T is distributed to the first axle shaft 22- 1 and the second axle shaft 22- 2 to drive the motor vehicle 10, the differential oil circulates through the first and second bearings 40- 1, 40- 2 to ensure appropriate durability and reliability of the drive axle 16.

Claims

An automotive drive axle (16) comprising: a drive axle housing (24) defining: a differential gearset cavity (28); a shaft bore (30) having first (32-1) and second (32-2) bearing pockets and an oil cavity (34) disposed between the first and second bearing pockets; an oil supply passage (36-1) configured to supply oil from the differential gearset cavity (28) into the oil cavity (34); and an oil return passage (36-2) configured to return oil from the oil cavity (34) into the differential gearset cavity (28); a differential gearset (26) disposed within the differential gearset cavity (28); an input shaft (38) extending through the shaft bore (30) into the differential gearset cavity (28) operatively connected to the differential gearset (26) and configured to transmit drive torque to the differential gearset (26); a first bearing (40-1) disposed in the first bearing pocket (32-1) and configured to support the input shaft (38) relative to the drive axle housing (24); a second bearing (40-2) disposed in the second bearing pocket (32-2) between the first bearing (40-1) and the differential gearset cavity (28) and configured to support the input shaft (38) relative to the drive axle housing (24); and a lubrication regulating insert (42) disposed within the oil cavity (34) and defining: a first lubrication channel (44-1) configured to direct oil from the oil supply channel (36-1) to the first bearing (40-1); and a second lubrication channel (44-2) configured to direct oil from the oil supply channel (36-1) to the second bearing (40-2), the lubrication regulating insert (42) additionally defining an oil dam (48) configured to maintain a preset oil level within the shaft bore (30) at the first bearing (40-1) and thereby minimize oil shortage of the first bearing (40-1), the lubrication regulating insert (42) additionally defining an oil collection sump (56) configured to:, in alignment with the oil supply passage (36-1) of the drive axle housing (24), and wherein each of the first lubrication passage (44-1) and the second lubrication passage (44-2) is in fluid communication with the oil collection sump (56), the first lubrication passage (44-1) being disposed at an angle to the second lubrication passage (44-2), the lubrication regulating insert (42) being constructed of a polymeric composite material, the drive axle housing (24) further defining a first feed passage (58-1) and a second feed passage (58-2) by casting, the first feed passage (58-1) being configured to direct oil from the first lubrication passage (44-1) to the first bearing (40-1), while the second feed passage (58-2) is configured to direct oil from the first lubrication passage (44-1) to the first bearing (40-1), A method of directing oil from the second lubrication passage (44-2) to the second bearing (40-2), wherein the lubrication regulating insert (42) includes a protrusion (60), the protrusion (60) being configured to engage and be located within a groove cast into the drive axle housing (24), the protrusion (60) being configured to index the lubrication regulating insert (42) into the shaft bore (30) to thereby align the oil collection groove (56) with the oil supply passage (36-1), a lubricant discharge opening (54) with the oil return passage (36-2), and the first and second supply passages (58-1, 58-2) with the respective first and second lubricant passages (44-1, 44-2).The motor vehicle drive axle (16) according to claim 1, wherein the lubrication regulating insert (42) is formed as a cylinder jacket arranged concentrically around a central axis.The motor vehicle drive axle (16) according to claim 2, wherein the oil dam (48) is defined by an annular flange arranged orthogonally to the cylinder jacket and extending towards the central axis.The motor vehicle drive axle (16) of claim 1, wherein the lubrication control insert (42) additionally defines the lubricant exit opening (54) in fluid communication with the oil return passage (36-2) of the drive axle housing (24).The motor vehicle drive axle (16) of claim 1, wherein the lubrication control insert (42) is press fit into the oil cavity (34).

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