Air pressure-controlled axle sump

Abstract

Axle tube, which includes: a transmission subsection (110) in which a transmission (114) is housed; an electric motor (112) having an outer housing (262), the electric motor (112) being at least partially surrounded by a motor tube (310), so that it comprises a motor sub-section (108), wherein the outer housing (262) has a drain opening (352); and a fluid cavity (318) defined by the outer housing (262) and the motor tube (310) is cooperatively limited, wherein the liquid cavity (318) and an interior space (350) of the electric motor (112) are in flow communication via the drain opening (352); wherein the transmission sub-section (110) and the motor sub-section (108) are attached to each other, wherein the transmission sub-section (110) is in flow connection with the interior (350) of the electric motor (112) through a first opening (338), wherein the gear sub-section (110) is in flow communication with the interior (350) of the electric motor (112) and the fluid cavity (318) through a second opening (336); and wherein the first opening (338) is at a greater height than the second opening (336).

Description

Area of ​​the Achssumpf

[0001] The present disclosure relates to managing an oil level in an axle or axle tube. Background of the invention

[0002] Oil is used as a lubricant and coolant for the components in an axle or axle tube. This coolant prevents overheating and helps extend the life of the components in the axle. More oil provides a larger volume for heat removal, but it is desirable to maintain a low oil level in rotating axle components to reduce churning losses.

[0003] A separate sump to hold a larger oil volume increases the cost of the vehicle and potentially requires additional pumps to move the oil to that location. The additional sump would also take up space on the vehicle, either complicating maintenance of other components or increasing the overall size of the vehicle.

[0004] DE 195 34 383 A1 discloses a drive device for a vehicle consisting of an electric motor and a reduction gear. To supply the lubricating fluid to the electric motor and the reduction gear, an inlet opening is provided on the motor housing and in a front plate that closes the motor housing in the area of ​​the output shaft bearing. Diametrically opposite the inlet opening, a drain opening for the lubricating fluid is arranged in the motor housing, which is in fluid communication with the stator chamber of the electric motor.

[0005] DE 202 01 379 U1 shows another drive system with electric drive motors and planetary gears, in which the oil lubrication of the motor shaft bearing is provided by the oil lubrication of the planetary gear. For this purpose, the motor shaft bearing is located in the gear housing, which is located inside the electric motor housing.

[0006] DE 603 ​​03 934 T2 discloses a drive device with an electric motor in a cylindrical casing and a gearbox, which are arranged together in a housing. To cool the electric motor, a pressurized lubricating fluid is directed between the space defined by the housing and casing in the circumferential direction of the stator. To lubricate the gearbox, the lubricating fluid is then directed to the hollow shaft of the rotor, which is in fluid communication with the hollow shaft of the gearbox. Brief presentation

[0007] The exemplary embodiments of the present disclosure include axle tubes and components for managing the lubricant level in the axle tube.

[0008] For example, there are four lubricant-cooled components in a single axle tube. These components are two final drives (located at each end of the axle tube and referred to as transmission subsections in the detailed description) and two motors (referred to as motor subsections in the detailed description) located in each end of the axle tube and connected to the final drives.

[0009] There are several target lubricant levels in the axle tube. The ideal lubricant level in the final drives is a few inches below the centerline. However, the engines operate best when all lubricant entering the engine is drained, so the engine does not contain stagnant lubricant.

[0010] Compensating for the lowest lubricant level that can be used in the final drives to reduce the lubricant level in the engines, the present disclosure presents a separate area as a sump or reservoir to maintain the lubricant volume required for adequate lubricant circulation. By way of example, the annular empty space between the engine housing and the axle tube is used as the sump volume. This utilizes existing features and existing empty space on the axle tube, eliminating the need to add a separate sump.

[0011] For example, a single drain hole is provided on the underside of the motor. Additional drain holes are provided to allow lubricant to flow from the final drive into the axle tube, directly into the annulus surrounding the motor. In this example configuration, these holes extend through the motor mounting plate but outside the motor housing. The final drive is internally designed to trap lubricant in the planetary gear reduction, where a higher lubricant level is desired. This can be achieved by blocking any path to the drain holes lower than a predetermined point below the centerline.

[0012] To achieve the desired lubricant volume in the sump, air pressure is supplied to the engine to create a pressure differential, allowing a higher lubricant level in the annulus surrounding the engine while maintaining a low level inside the engine. The air pressure can be supplied either by a stand-alone air pump or it can be taken from an engine turbocharger. A hole is punched through the engine mounting plate to connect the inside of the engine housing to the final drive. This allows airflow into the final drive. A breather is connected to the wet sections of the axle tube to maintain minimal back pressure on the lubricant in the sump / annulus. The pressure differential from inside the engine / final drive to the wet axle tube forces a higher level into the axle tube and a lower level into the engine and final drive.

[0013] The exemplary embodiments allow for sharing a single lubricant system between the engine and the final drive. Due to atmospheric pressure and the internal design of the final drive, the system can self-regulate different lubricant levels within the two components to utilize a common sump to meet the lubrication needs of both the engine and the final drive.

[0014] A first aspect of the present disclosure is to provide an axle tube comprising: (a) a transmission sub-portion housing a transmission; (b) an electric motor having an outer casing, the electric motor being at least partially surrounded by a motor tube to comprise a motor sub-portion, the outer casing having a vent opening;and (c) a fluid cavity cooperatively defined by the outer housing and the motor tube, the fluid cavity and an interior of the electric motor being in fluid communication via the drain opening, the transmission sub-section and the motor sub-section being attached to each other, the transmission sub-section being in fluid communication with the interior of the electric motor through a first opening, the transmission sub-section being in fluid communication with the interior of the electric motor and the fluid cavity through a second opening, and the first opening being at a greater height than the second opening;

[0015] In a more detailed embodiment of the first aspect, the electric motor includes an air inlet port communicating with the interior of the electric motor, and the motor subsection includes a lubricant inlet port communicating with an interior of the motor subsection. In another even more detailed embodiment, the transmission subsection and / or the motor subsection includes a drain port fluidly connected to a pump via a first conduit to withdraw fluid, and the transmission subsection and / or the motor subsection includes a fluid inlet port fluidly connected to the pump via a second conduit to supply fluid to the transmission subsection and / or the motor subsection.In a further detailed embodiment, the second conduit is in fluid communication with a fluid filter in the conduit, and the second conduit is in fluid communication with a fluid cooler in the conduit. In yet another detailed embodiment, the second conduit is in fluid communication with a fluid manifold, the fluid manifold divides the second conduit into a first inlet conduit and a second inlet conduit, the first inlet conduit is in fluid communication with an interior of the transmission subsection, and the second inlet conduit is in fluid communication with an interior of the engine subsection.In a detailed embodiment, the motor sub-section includes an end plate having a passage through which a motor shaft of the electric motor extends into the transmission sub-section, the end plate including the first opening and the second opening, the first opening being located above the passage and the second opening being located below the passage.

[0016] A second aspect of the present invention is to provide an axle tube comprising: (a) a right-side transmission sub-portion housing a right-side transmission; (b) a left-side transmission sub-portion housing a left-side transmission; (c) a right-side electric motor having a right-side outer casing, the right-side electric motor being at least partially surrounded by a motor tube to include a motor sub-portion, the right-side outer casing having a first drain opening; (d) a left-side electric motor having a left-side outer casing, the left-side electric motor being at least partially surrounded by the motor tube to include a portion of the motor sub-portion, the left-side outer casing having a second drain opening; and (e) a fluid cavity defined by the right-side outer casing,the left-side outer housing and the motor tube are cooperatively defined, wherein the fluid cavity and an interior of the right-side electric motor are in flow communication via the first drain opening, wherein the fluid cavity and an interior of the left-side electric motor are in flow communication via the second drain opening, wherein the right-side transmission subsection and the motor subsection are attached to one another, wherein the left-side transmission subsection and the motor subsection are attached to one another, wherein the right-side transmission subsection is in flow communication with the interior of the right-side electric motor through a first passage, wherein the right-side transmission subsection is in flow communication with the interior of the right-side electric motor and the fluid cavity through a second passage,wherein the left-side transmission sub-section is in fluid communication with the interior of the left-side electric motor through a third passage, wherein the left-side transmission sub-section is in fluid communication with the interior of the left-side electric motor and the fluid cavity through a fourth passage, and wherein the first and third passages are at a greater height than the second and fourth passages, respectively.

[0017] In a more detailed embodiment of the second aspect, the right-side electric motor includes an air inlet port communicating with the interior of the right-side electric motor, the right-side motor sub-portion includes a lubricant inlet port communicating with an interior of the right-side motor sub-portion, the left-side electric motor includes an air inlet port communicating with the interior of the left-side electric motor, and the left-side motor sub-portion includes a lubricant inlet port communicating with an interior of the left-side motor sub-portion.In yet another more detailed embodiment, the right-side motor subsection includes an end plate having a passage through which a motor shaft of the right-side electric motor extends into the right-side transmission subsection, the end plate including the first opening and the second opening, the first opening being above the passage and the second opening being below the passage, and the left-side motor subsection includes an end plate having a passage through which a motor shaft of the left-side electric motor extends into the left-side transmission subsection, the end plate including the third opening and the fourth opening, the third opening being above the passage and the fourth opening being below the passage.

[0018] A third aspect of the present invention is to provide a method for controlling fluid levels in an axle tube, the method comprising: (a) establishing a first predetermined level of liquid lubricant in a transmission and an electric motor operatively coupled to the transmission, the axle tube housing the electric motor and the transmission, a cavity disposed between a wall of the axle tube and the electric motor being occupied by the liquid lubricant reservoir at a second predetermined height; and (b) lowering the first predetermined liquid lubricant level in the electric motor and the transmission by changing a gas pressure applied to the liquid lubricant, the second predetermined liquid lubricant level in the cavity being raised by changing the gas pressure applied to the liquid lubricant in the axle tube.

[0019] In a more detailed embodiment of the third aspect, the process of changing the gas pressure applied to the liquid lubricant comprises forcing compressed air into the axle tube, the compressed air coming from a vent of a turbocharger. In yet another more detailed embodiment, the process of changing the gas pressure applied to the liquid lubricant comprises forcing air into the axle tube using an air compressor. In a further detailed embodiment, the process of changing the gas pressure applied to the liquid lubricant comprises applying suction to the cavity. In yet another detailed embodiment, the first predetermined level of liquid lubricant is different in the transmission and the electric motor.In a more detailed embodiment, the gearbox and an interior of the electric motor are in gas communication with each other through a first passage, the gearbox and the cavity are in liquid communication with each other through a second passage, and the first predetermined liquid lubricant level in the electric motor prevents gas communication between the interior of the gearbox and the cavity.

[0020] A fourth aspect of the present invention is to provide a method for distributing a liquid lubricant in an axle tube, the method comprising: (a) using a cavity disposed between an electric motor and a wall of the axle tube as a liquid lubricant reservoir, the axle tube housing the electric motor and the transmission; and (b) changing the amount of liquid lubricant in the reservoir by changing a pressure of a gas in contact with the liquid lubricant in the axle tube.

[0021] In a more detailed embodiment of the fourth aspect, the method comprises (c) providing a predetermined amount of liquid lubricant in the axle tube, (d) maintaining the predetermined amount of liquid lubricant in the axle tube, and (e) lowering a liquid lubricant level in the electric motor and / or the transmission, wherein changing the amount of liquid lubricant in the reservoir does not change the predetermined amount of liquid lubricant in the axle tube. In yet another more detailed embodiment, the axle tube includes a second cavity disposed between a second electric motor and the wall of the axle tube as a second liquid lubricant reservoir, and the axle tube houses the second electric motor and a second transmission.In a further detailed embodiment, the axle tube includes a dry section between the electric motor and the second electric motor, and the cavity is in fluid communication with the second cavity via a connecting conduit. In yet another detailed embodiment, the process of changing the pressure of the gas associated with the liquid lubricant comprises applying suction to the reservoir. Short description of the drawings Fig. 1 is a top perspective view of an exemplary axle tube according to the present disclosure, shown without external fluid and electrical conduits. Fig. 2 is a perspective elevation of the exemplary axle tube in Fig. 1 from the bottom. Fig. 3 is a cross-sectional view of the exemplary axle tube in Fig. 1. Fig. 4 is a perspective elevation of the exemplary dry central section of Fig. 1 from the top. Fig. 5 is a perspective elevation of the exemplary dry central section of Fig. 4 from the bottom. Fig. 6 is a perspective elevation of the exemplary dry central section of Fig. 1 from the front, without a pair of walls, showing the pair of electric motors attached to the dry central section. Fig. Figure 7 is a perspective elevational view, from the electric motor side, of a cross-section relative to the transmission subsection and the motor subsection housing to show the position of the electric motor relative to adjacent components. Fig. Figure 8 is a perspective elevational view, from the gearbox side, of a cross-section relative to the gearbox subsection to show the position of the electric motor and tube relative to adjacent components. Fig. 9 is a schematic diagram showing the lubricant level in the exemplary axle tube of Fig. 1 before the start. Fig. 10 is a schematic diagram illustrating the lubricant level in the exemplary axle tube of Fig. 1 at startup. Fig. 11 is a schematic diagram illustrating the lubricant level in the exemplary axle tube of Fig. 1 after start-up, after the air pressure in the subsections has become large enough to displace a larger amount of lubricant into a storage cavity. Fig. 12 is a top perspective view of an exemplary axle tube according to the present disclosure, shown with external fluid lines. Fig. 13 is an enlarged view of a portion of Fig. 12. Fig. 14 is an example flowchart for the Fig. 12 shown axle tube. Fig. 15 is an example flow diagram for another example axle tube. Fig. 16 is an alternative exemplary flow diagram for another alternative exemplary axle tube. Detailed description

[0022] The exemplary embodiments of the present disclosure are described and illustrated below as including axle tubes and methods for managing fluid levels in an axle tube. It will be appreciated by one of ordinary skill in the art that the exemplary embodiments discussed below are merely examples and may be reconfigured without departing from the scope and spirit of the present disclosure. However, for clarity and clarity, the exemplary embodiments discussed below may include optional steps, methods, and features that, as one of ordinary skill in the art should recognize, are not required to fall within the scope of the present invention.

[0023] On the Fig. 1-3, a first exemplary axle tube 100 (shown without external fluid hoses) includes a dry center section 102 and corresponding right and left wet sections 104, 106 attached to opposite ends of the dry center section. In this exemplary embodiment, the right and left wet sections 104, 106 each include two subsections 108, 110. The first subsection 108 is a motor subsection that houses the majority of an electric motor 112. The second subsection 110 is a transmission subsection and includes transmission components 114 operatively coupled to the electric motor 112. Both the right and left wet sections 104, 106 are sealed to retain oil, which simultaneously lubricates and cools the transmission components 114 and cools the electric motor 112.Both wet sections 104, 106 contain seals that act to retard the inflow of water and other contaminants.

[0024] On the Fig. Referring to Figures 1-6, the dry central section 102 includes a shell formed by six rectangular walls 230, 232, 234, 236, 238, 240 secured together. Each of the six walls 230, 232, 234, 236, 238, 240 corresponds to a different one of the remaining five walls, such that corresponding pairs of walls are generally evenly spaced and aligned in parallel. This alignment provides a box-shaped shell defining a dry interior cavity 246.

[0025] The first corresponding pair of walls 230, 234 (right and left) each contains a circular through-hole 250 large enough to accommodate a dry portion 252 of an electric motor 112. As discussed in more detail below, the majority of the electric motor 112 is housed within the motor subsection 108. Respective elastomeric ring seals 260 are disposed between an outer housing 262 of each electric motor 112 and an outer surface 264 of each wall 230, 234. In particular, the elastomeric ring seal 260 has a diameter larger than the diameter of the through-hole 250, such that the ring seal circumscribes the through-hole but is attached to the outer surface 264 of each wall 230, 234. In particular, the outer surface 264 includes a circular recess 266 that defines the through hole 250 and provides a seat for a portion of the ring seal 260.It should be noted that the housing 262 of each electric motor 112 is simultaneously attached to the sealing ring 260, but is not rigidly secured to the dry center section 102. Instead, the electric motor 112 floats relative to the dry center section 102 due to the flexibility of the sealing rings 260 disposed between the walls 230, 234 and the housing 262 of each electric motor 112.

[0026] The second corresponding pair of walls 232, 236 (front and rear) are coupled to the right and left walls 230, 234 and to the third corresponding pair of walls 238, 240 (top and bottom). The front and rear walls 232, 236 each include a plurality of openings 270 configured to provide a mounting location for attaching the axle tube to a vehicle frame (not shown), thereby supporting the center of the axle tube. The top and bottom walls 238, 240 each include a rounded, rectangular through-hole 272. In this exemplary embodiment, the rounded, rectangular through-hole 272 of the bottom wall 238 is closed by a rounded, rectangular trough 276 attached to an outer surface 278 thereof.In particular, the rounded, rectangular tray 276 includes a plurality of openings (not shown) configured to receive threaded fasteners 280 extending through the openings and into holes in the bottom wall 240 to permit coupling and detachment of the tray to and from the bottom wall. However, the rounded, rectangular through-hole 272 of the top wall 238 is not completely closed. Instead, a rounded, rectangular tray 284 having a pair of elongated, rectangular passages 286 is mounted on an exterior surface of the top wall 238. As with the lower tray 276, the upper tray 284 includes a plurality of openings (not shown) configured to receive threaded fasteners 290 extending through the openings and into holes in the top wall 238 to permit coupling and detachment of the upper tray to and from the top wall.Adapter boxes 294 extend from the upper tub 284 and circumscribe the elongated, rectangular passages 286. Each adapter box 294 houses a high-voltage subassembly (not shown) that is preconnected and fluidly sealed to provide electrical connection from outside the dry center section 102 and in communication with the electric motors 112 partially disposed within the dry center section. The adapter boxes 294 also provide connection points for the air, oil, and low-voltage lines (not shown) connected to the electric motors 112. The upper tub 284 further includes a plurality of secondary openings 296 disposed between the adapter boxes 294.

[0027] The dry portion 252 of each electric motor 112 includes numerous connections that establish electrical and fluid communication with the internal components of the electric motor and the transmission components 114. Several electrical connections 300 are provided to supply electrical power to the internal components. One skilled in the art will be familiar with the structure of electric motors, and a corresponding detailed discussion of the internal components of each electric motor has been omitted for brevity. In addition to the electrical connections 300, the dry portion 252 further includes an oil supply port 302 near the lower end of the dry portion for introducing oil into the interior of the electric motor 112. Furthermore, an air supply port 304 is provided as part of the dry portion 252 near the upper end of the dry portion for introducing air into the interior of the electric motor 112.

[0028] On the Fig. 1 and Fig. 7, the remainder of the electric motor 112 is housed in a tube 310 of the motor subsection 108. The tube 310 includes a two-layer 312, 314 cylinder with a series of fluid connections 316 that allow fluid communication between the interior of the tube and a tube exterior. As discussed in more detail below, the fluid connections 316 are connected to hoses (see Fig. 12 and Fig. 13). Between the inner layer 314 of the tube 310 and the exterior of the electric motor housing 262 is a reservoir cavity 318, which is used to store excess oil when the axle tube 100 is in operation. Both layers 312, 314 of the tube 310 are welded at one longitudinal end to the outer surface 264 of respective walls 230, 234.

[0029] On the Fig. 7 and Fig. Referring to Figure 8, the opposite longitudinal end of each tube 310 is welded to a circular flange 320 having a plurality of through holes. A first circumferentially outermost set of holes 322 receives fasteners for securing the flange 320 to a corresponding flange 360 ​​of the transmission subsection 110. A second, not shown, inner circumferential set of holes receives fasteners 324 for securing the flange 320 to an end plate 330 of the electric motor 112. A gasket 332 is disposed between the flange 320 and the end plate 330 to ensure a fluid-tight seal therebetween.

[0030] The end plate 330 includes a plurality of holes with different functionality. A first set of holes receives the fasteners 324 for securing the electric motor 112 to the flange 320. A second set of through-holes 336 provides a connection at the end plate 330. As discussed in more detail below, these holes 336 provide a path for fluid (e.g., coolant / lubricant such as oil) to flow between the interior of the transmission subsection 110 and the reservoir cavity 318. To manage fluid flow between the interior of the transmission subsection 110 and the reservoir cavity 318, the end plate 330 further includes a through-hole 338 positioned higher than an output shaft 340 from the electric motor 112 and above the second set of through-holes 336.The through-hole 338 is configured to provide a path for fluid (e.g., air) to flow between the interior of the transmission subsection 110 and the electric motor housing 262. As air pressurizes the interior of the transmission subsection 110 and the interior of the electric motor housing 262, coolant / lubricant is forced into the reservoir cavity 318.

[0031] On the Fig. Referring to Figures 9-11, a schematic diagram shows the transmission subsection 110 and the engine subsection 108 coupled together and fluidly sealed from each other. In this manner, lubricant / coolant (e.g., oil) 400 can flow between the subsections 108, 110, however, the subsections generally hold the same aggregate volume (subsection 108 plus subsection 110) of lubricant / coolant. And the amount of lubricant / coolant 400 located in either of the subsections 108, 110 changes depending on whether the axle tube 100 is operational or not.

[0032] Referring to Figures 7-9, initially, when the axle tube 100 becomes operational (upon receiving electrical power to drive the electric motors 112 and an air supply, and when it is on level ground), the level of the lubricant / coolant 400 within the subsections 108, 110 is generally the same. The universal level is the result of the lubricant / coolant 400 being able to flow freely through the second set of through-holes 336 of the end plate 330 (see Fig. 7 and Fig. 8). In particular, the level of lubricant / coolant 400 is the same in the transmission subsection 110, the reservoir cavity 318, and the internal cavity 350 of the electric motor 112. However, this universal level does not remain the same during operation of the axle tube 100.

[0033] On the Fig. 6 - 8 and 10, after the axle tube 100 has become operative (upon receipt of electrical power to drive the electric motors 112 and an air supply (for example, air source 572 in Fig. 14), and when on level ground), air is supplied via the air supply port 304 in the dry portion 252 into the internal cavity 350 of the electric motor 112. The pressure of the air in the internal cavity 350 of the electric motor 112 builds due to the air supply supplying air above atmospheric pressure. Illustratively, the air supply supplies air to approximately 40 psig (pounds per square inch gauge), which is reduced before it reaches the air supply port 304. The air pressure in the electric motor 112 may, for example, be between 0.4 - 1.0 psig to overcome the head pressure in the reservoir cavity 318 and force oil out of the interior of the electric motor through a drain 352 at the base of the electric motor housing 262.As the air drives out all or almost all of the lubricant 400 in the interior 350 of the electric motor 112, the air eventually begins to escape through the drain 352 and into the reservoir cavity 318, from which it is vented via a vent 580. In this way, the air pressure in the interior 350 of the electric motor 112 can be self-regulated. As the air pressure builds up in the interior cavity 250, the air also escapes through the through-hole 338 of the end plate 330, which is at a higher elevation than the output shaft 340. Thus, the air pressure at the through-hole 338 is essentially the same. This means that the air pressure in the interior cavity 350 of the electric motor 112 is the same as the air pressure in the transmission subsection 110.Due to this pressure equalization, the level of lubricant / coolant 400 at the through-holes 336 in the transmission subsection 110 and in the internal cavity 350 of the electric motor 112 is substantially the same. However, it should be noted that the transmission subsection 110 includes a retaining wall 354 that acts to maintain a predetermined level of lubricant 400 within a portion of the transmission subsection that is above the level of lubricant at the through-holes 336. The level of lubricant in the reservoir cavity 318 is also higher than the level of lubricant at the through-holes 336.

[0034] On Fig. Referring to Figure 11, as air pressure builds within the transmission subsection 110 and the internal cavity 350 of the electric motor 112, the higher-pressure air begins to displace the lubricant / coolant 400 within these areas. As the air displaces the lubricant / coolant 400, the corresponding level of the lubricant / coolant 400 within the transmission subsection 110 and the internal cavity 350 drops, and the lubricant / coolant is forced into the reservoir cavity 318, causing the level of the lubricant / coolant to rise dramatically—well above the level in the transmission subsection and the internal cavity 350 of the electric motor 112.Eventually, the level of lubricant / coolant 400 in the transmission subsection 110 and in the internal cavity 350 reaches an operating level when a balance is established between the air pressure pushing against the lubricant / coolant and the pressure of the lubricant / coolant pushing back against the air. This operating level of lubricant / coolant 400 is determined in large part based on the operating pressure of the air supply. However, those skilled in the art will appreciate that the operating pressure of lubricant / coolant 400 may change, and thus the air pressure supplied by the air supply may also change to accommodate these changes in the operating level of lubricant / coolant.

[0035] When the axle tube 100 is no longer operational (no electrical current to drive the electric motors 112 and no air supply, and when it is on level ground), the level of the lubricant / coolant 400 in the subsections 108, 110 returns to a uniform level (see Fig. 9). In particular, without the air pressure forcing the lubricant / coolant 400 into the reservoir cavity 318, the pressure of the lubricant / coolant in the reservoir cavity acts to displace the air and be evenly distributed between the subsections 108, 110.

[0036] On the Fig. Referring to Figures 11-14, the lubricant / coolant 400 flows through a closed circuit 500 that includes the interior of the subsections 108, 110 and a series of interconnected conduits. Each tube 310 includes an outlet opening defined by an outlet port fitting 502 positioned near the lowest arcuate point on the tube. The outlet port fitting 502 is attached to a rigid outlet conduit 504, which is attached to a flexible outlet conduit 506. In this manner, the fitting 502 and conduits 504, 506 cooperate to provide a sealed flow of the lubricant / coolant 400 exiting the reservoir cavity 318 and flowing to the end of the outlet conduit 506. Each end of both flexible outlet conduits 506 is connected to a T-connector 508 which acts to combine the two streams into a single flexible conduit 514.The flexible line 514 is operatively coupled to a pump 516, which presses the lubricant / coolant 400 into a flexible outlet line 520, which conveys the lubricant / coolant to be cooled and cleaned.

[0037] The lubricant / coolant 400 is conveyed through the flexible conduit 520 and directed into a cooler 526, through which a second fluid flows to lower the temperature of the lubricant / coolant. After cooling the lubricant / coolant 400, a cooler outlet conduit 528 conveys the lubricant / coolant to a filter 530. The filter 530 functions to remove contaminants from the lubricant / coolant 400 and discharge clean lubricant / coolant into a supply conduit 534.

[0038] The supply line 534 is coupled to a manifold 536, which acts to distribute the lubricant / coolant 400 between a plurality of input lines 540, 542. The first pair of input lines 540 is each coupled to a rigid line 548, which is coupled to an inlet port fitting 550 defining an inlet port. The inlet port fitting 550 is attached to the flange 360 ​​of the transmission subsection 110 and provides an outlet point for the lubricant / coolant 400 to flow into the interior of the transmission subsection. The second pair of input lines 542 extend through the secondary ports 296 (see Fig. 5) of the upper pan 284 and in connection with the oil supply connection piece 302 of the electric motor 112 (see Fig. 6), thereby providing an outlet point for lubricant / coolant 400 to flow into the interior of the electric motor.

[0039] Direct flow communication between the engine subsections 108 is enabled by a connecting line 560 coupled to respective outlet ports 562 mounted at locations on the tube 310 that are higher than the outlet port ports 502. In this manner, the lubricant / coolant 400 can be freely discharged from a reservoir cavity 318 (see Fig. 7) to the other reservoir cavity. The connecting line 560 comprises two mirror-image sections of a rigid line (which generally retains its shape) coupled to a box fitting 563. The box fitting 563 is coupled to a bypass line 564, which is also coupled to the manifold 536. In this way, if the input lines 540, 542 become damaged or clogged, the manifold detects the resulting pressure difference (higher or lower) and redirects the lubricant / coolant 400 from the manifold 536 into the bypass line 564, where the lubricant / coolant is directed into the respective reservoir cavities 318 using the connecting line 560. Otherwise, the bypass line 564 contains stagnant lubricant / coolant 400. And, as shown in part in the Fig. 10 and Fig. 11, an air supply line 570 supplies air from an air source 572 to the air supply port 304 of the electric motor 112. Example air sources include, but are not limited to, turbochargers and air compressors. In this example embodiment, it is contemplated that the axle tube 100 may be included as part of a larger machine having an internal combustion engine with a turbocharger, with at least a portion of the exhausted pressurized air from the turbocharger being routed through the air supply line 570. It should also be noted that the tube 310 includes a vent opening 580 that may be operatively coupled to a vent line (not shown) to vent air in the reservoir cavity 318 as the amount of lubricant / coolant 400 increases, while simultaneously admitting air into the reservoir cavity as the amount of lubricant / coolant decreases.

[0040] On the Fig. 15 and Fig.16, an additional set of schematic diagrams shows other flow paths 600, 700 in the closed loop for the lubricant / coolant 400. In this first other closed loop 600, the conduits and components are the same as in the first closed loop 500 except for the provision of an air source 572 or an air supply conduit 570. Under such circumstances, the lubricant / coolant 400 in subsections 108, 110 is not actively managed to direct more lubricant / coolant to the reservoir cavities 318 when the electric motor 112 and transmission components are operational.

[0041] The second alternative closed circuit 700 includes the lines and components of the first closed circuit 500, except for the omission of the dry center section 102 and the connecting line 560. In this way, the lubricant / coolant 400 is directed directly into the engine subsection 108 and drawn directly from the engine subsection. Likewise, the air supply line is split and directly coupled to each engine subsection 108. In this alternative embodiment, the lines for the lubricant / coolant 400, the electrical lines to the electric motors, and the air supply line must be capable of withstanding partial or total submersion in the lubricant / coolant due to the absence of the dry center section 102.

[0042] It should be noted that while the previous embodiment was discussed using pressurized air to raise the level of lubricant / coolant 400 in the reservoir cavity 318, it is also within the scope of the disclosure to apply suction to the upper end of the reservoir cavity to draw additional lubricant / coolant within the reservoir cavity. In such circumstances, the vent 580 may be coupled to a suction line (not shown) that acts to create a vacuum region within the reservoir cavity 318 to raise the level of lubricant / coolant 400.

[0043] From the above description and the above invention summaries, it should be apparent to one of ordinary skill in the art that while the methods and apparatus described herein constitute exemplary embodiments of the present invention, the invention contained herein is not limited to that precise embodiment, and that changes may be made to such embodiments without departing from the scope of the invention as defined by the claims. Furthermore, it is to be understood that the invention is defined by the claims, and it is not intended that any limitations or elements describing the exemplary embodiments recited herein be incorporated into the interpretation of any claim element unless such a limitation or element is explicitly recited.Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclosed herein in order to fall within the scope of any claims, since the invention is defined by the claims and there may be inherent and / or unforeseen advantages of the present invention even though they may not be explicitly discussed herein.

Claims

[1] Axle tube comprising: a transmission subsection (110) in which a transmission (114) is housed; an electric motor (112) having an outer housing (262), the electric motor (112) being at least partially surrounded by a motor tube (310), so that it comprises a motor sub-section (108), wherein the outer housing (262) has a drain opening (352); and a fluid cavity (318) defined by the outer housing (262) and the motor tube (310) is cooperatively limited, wherein the liquid cavity (318) and an interior space (350) of the electric motor (112) are in flow communication via the drain opening (352); wherein the transmission sub-section (110) and the motor sub-section (108) are attached to each other, wherein the transmission sub-section (110) is in flow connection with the interior (350) of the electric motor (112) through a first opening (338), wherein the gear sub-section (110) is in flow communication with the interior (350) of the electric motor (112) and the fluid cavity (318) through a second opening (336); and wherein the first opening (338) is at a greater height than the second opening (336). [2] Axle tube according to claim 1, wherein: the electric motor (112) includes an air inlet opening (304) communicating with the interior (350) of the electric motor (112); and the engine sub-section (108) includes a lubricant inlet opening (302), which communicates with an interior of the engine sub-section (108). [3] Axle tube according to claim 1, wherein the transmission sub-section (110) and / or the motor sub-section (108) includes / include a drain port (316) that is in fluid communication with a pump (516) via a first conduit (506) for withdrawing fluid; and the transmission sub-section (110) and / or the motor sub-section (108) includes / include a fluid inlet opening (302, 550) which is in fluid communication with the pump (516) via a second conduit (520) in order to supply fluid to the transmission sub-section (110) and / or the motor sub-section (108). [4] Axle tube according to claim 3, wherein: the second conduit (520) is in flow communication with a liquid filter (530) in the conduit; and the second line (520) is in flow connection with a liquid cooler (526) in the line. [5] Axle tube according to claim 4, wherein: the second conduit (520) is in fluid communication with a fluid distributor (536); the fluid distributor (536) divides the second conduit (520) into a first inlet conduit (540) and a second inlet conduit (542); the first inlet line (540) is in flow communication with an interior of the transmission sub-section (110); and the second inlet line (542) is in flow communication with an interior of the engine sub-section (108). [6] The axle tube of claim 1, wherein the motor sub-section (108) includes an end plate (330) having a passage through which a motor shaft (340) of the electric motor (112) extends into the transmission sub-section (110), the end plate (330) including the first opening (338) and the second opening (336), the first opening (338) being located above the passage and the second opening (336) being located below the passage. [7] Axle tube according to claim 1, wherein: the transmission subsection has a right-hand transmission subsection (110), in which a right-hand transmission (114) is housed, and a left-hand transmission sub-section (110) in which a left-hand transmission (114) is housed; the electric motor (112) comprises a right-side electric motor (112) and a left-side electric motor (112); wherein the right-side electric motor (112) has a right-side outer housing (262), wherein the right-side electric motor (112) is at least partially surrounded by a motor tube (310) to include a motor sub-section (108), wherein the right-side outer housing (262) has a first vent opening (352); and wherein the left-side electric motor (112) has a left-side outer housing (262), wherein the left-side electric motor (112) is at least partially surrounded by the motor tube (310) to encompass a portion of the motor sub-section (108), wherein the left-side outer housing (262) has a second vent opening (352); and the liquid cavity (318) through the right-hand outer housing (262), the left-side outer housing (262) and the motor tube (310) are cooperatively limited; wherein the liquid cavity (318) and an interior space (350) of the right-side electric motor (112) are in flow connection via the first drain opening (352), wherein the fluid cavity and an interior space (350) of the left-side electric motor (112) are in flow communication via the second drain opening (352); wherein the right-side transmission sub-section (110) and the motor sub-section (108) are attached to each other, wherein the left-side transmission sub-section (110) and the motor sub-section (108) are attached to each other, wherein the right-side transmission sub-section (110) is in fluid communication with the interior (350) of the right-side electric motor (112) through the first passage (338); wherein the right-side transmission sub-section (110) is in flow communication with the interior (350) of the right-side electric motor (112) and the fluid cavity (318) through the second passage (336), wherein the left-side transmission sub-section (110) is in flow communication with the interior (350) of the left-side electric motor (112) through a third passage (338), wherein the left-side transmission sub-section (110) is in fluid communication with the interior (350) of the left-side electric motor (112) and the fluid cavity (318) through a fourth passage (336); and wherein the first and third passages (338) are at a greater height than the second and fourth passages (336), respectively. [8] Axle tube according to claim 7, wherein: the right-side electric motor (112) includes an air inlet opening (304) which communicates with the interior (350) of the right-side electric motor (112), the right-side engine sub-section (108) includes a lubricant inlet opening (302) communicating with an interior of the right-side engine sub-section (108); the left-side electric motor (112) includes an air inlet opening (304) communicating with the interior (350) of the left-side electric motor (112); and the left-side engine sub-section (108) includes a lubricant inlet opening (302) communicating with an interior of the left-side engine sub-section (108). [9] Axle tube according to claim 7, wherein: the right-side motor subsection (108) includes an end plate (330) having a passage through which a motor shaft (340) of the right-side electric motor (112) extends into the right-side transmission subsection (110), the end plate (330) including the first opening (338) and the second opening (336), the first opening (338) being located above the passage and the second opening (336) being located below the passage; and the left-side motor sub-section (108) includes an end plate (330) with a passage through which a motor shaft (340) of the left-side electric motor (112) extends into the left-side transmission sub-section (110), wherein the end plate (330) includes the third opening (338) and the fourth opening (336), the third opening (338) being located above the passage and the fourth opening (336) is located below the passage. [10] A method for controlling fluid levels in an axle tube (100), the method comprising: Setting a first predetermined level of a liquid lubricant (400) in a transmission (114) and an electric motor (112) operatively coupled to the electric motor (112), wherein the electric motor (112) and the transmission are housed in the axle tube (100), wherein a liquid cavity (318) arranged between a wall (314) of the axle tube (100) and the electric motor (112) is occupied by the liquid lubricant (400) at a second predetermined level; and Lowering the first predetermined level of liquid lubricant (400) in the electric motor (112) and the transmission by changing a gas pressure applied to the liquid lubricant (400); wherein by changing the gas pressure applied to the liquid lubricant (400) in the axle tube (100), the second predetermined level of lubricant (400) in the liquid cavity (318) is increased. [11] The method of claim 10, wherein the act of changing the gas pressure applied to the liquid lubricant (400) comprises forcing compressed air into the axle tube (100), the compressed air coming from a vent of a turbocharger (572). [12] The method of claim 10, wherein the act of changing the gas pressure applied to the liquid lubricant (400) comprises forcing air into the axle tube (100) using an air compressor (572). [13] The method of claim 10, wherein the act of changing the gas pressure applied to the liquid lubricant (400) comprises applying suction to the liquid cavity (318). [14] The method of claim 10, wherein the first predetermined level of liquid lubricant (400) in the transmission and the electric motor (112) is different. [15] The method of claim 10, wherein the transmission and an interior (350) of the electric motor (112) are in gas communication with each other through a first passage (338); the gear and the fluid cavity (318) are in fluid communication with each other through a second passage (336); and the first predetermined level of liquid lubricant (400) in the electric motor (112) prevents gas communication between the interior (350) of the transmission and the liquid cavity (318). [16] A method for distributing a liquid lubricant (400) in an axle tube (100), the method comprising: Using a cavity arranged between an electric motor (112) and a wall (314) of the axle tube (100) as a liquid lubricant reservoir (318), wherein the electric motor (112) and a transmission (114) are accommodated in the axle tube (100); and Changing the amount of liquid lubricant (400) in the liquid lubricant reservoir (318) by changing a pressure of a gas, which is in contact with the liquid lubricant (400) in the axle tube (100). [17] The method of claim 16, further comprising: Providing a predetermined amount of the liquid lubricant (400) in the axle tube (100); Maintaining the predetermined amount of liquid lubricant (400) in the axle tube (100); and Lowering a level of the liquid lubricant (400) in the electric motor (112) and / or the transmission; wherein changing the amount of liquid lubricant (400) in the liquid lubricant reservoir (318) does not change the predetermined amount of liquid lubricant (400) in the axle tube (100). [18] The method of claim 16, wherein: the axle tube (100) includes a second cavity disposed between a second electric motor (112) and the wall of the axle tube (100) as a second liquid lubricant reservoir (318); and The second electric motor (112) and a second gear (114) are housed in the axle tube (100). [19] The method of claim 18, wherein: the axle tube (100) includes a dry section (102) between the electric motor (112) and the second electric motor (112); and the liquid cavity is in flow connection with the second cavity via a connecting line (560). [20] The method of claim 16, wherein the act of changing the pressure of the gas in communication with the liquid lubricant (400) comprises applying suction to the liquid lubricant reservoir (318).

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