Articulated axle for transmitting drive torque of a motor vehicle

Abstract

An articulated axle for transmitting drive torque of a motor vehicle to at least one drive wheel is provided with a connecting shaft for coupling a transmission to the drive wheel in a torque-transmitting manner, an inner tilting joint on the transmission side for coupling the connecting shaft to the transmission in a tiltable and torque-transmitting manner, an outer tilting joint on the wheel side for coupling the connecting shaft to the drive wheel in a tiltable and torque-transmitting manner, and a cooling channel through the connecting shaft for fluidically connecting the inner tilting joint with the outer tilting joint for a flow-through of a cooling fluid. The cooling channel formed within the torque-transmitting connecting shaft can be used to cool and lubricate the tilting joints in a space-saving manner without significant adverse effects on the mechanical properties of the connecting shaft, thereby achieving a space-saving and low-wear articulated axle.

Description

Technical Field

[0001] The present invention relates to an articulated shaft through which the driving torque of a motor vehicle can be transmitted to the drive wheels of the motor vehicle, and the present invention relates to a motor vehicle having such an articulated shaft. Background Technology

[0002] DE 102 30 768 A1 illustrates a half-shaft extending from the differential of a motor vehicle to the hub of a drive wheel, with a screw conveyor on one half of the half-shaft to deliver lubricant for cooling purposes between the half-shaft and a conduit surrounding the half-shaft to a planetary gear train disposed in the respective hub, wherein the lubricant is circulated within the half-shaft.

[0003] In motor vehicles, there is always a need to reduce wear and tear in a space-saving manner. Summary of the Invention

[0004] The object of this invention is to provide a method for achieving a hinge shaft that is both space-saving and has low wear.

[0005] According to the present invention, the objective is achieved by an articulated shaft having the features described in technical solution 1 and a motor vehicle having the features described in technical solution 9. Preferred embodiments of the present invention are disclosed in the dependent claims and the following description, which, individually or in combination, may constitute an aspect of the present invention, wherein the scope of protection is determined by the claims.

[0006] One aspect of the invention relates to an articulated shaft for transmitting drive torque of a motor vehicle to at least one drive wheel, the articulated shaft comprising: a connecting shaft for connecting a transmission to the drive wheel in a torque-transmitting manner; an inner tilt joint on the transmission side for connecting the connecting shaft to the transmission in a tiltable and torque-transmitting manner; an outer tilt joint on the wheel side for connecting the connecting shaft to the drive wheel in a tiltable and torque-transmitting manner; and a cooling channel through the connecting shaft for fluidly connecting the inner tilt joint and the outer tilt joint for the flow of cooling fluid.

[0007] It has been found that, unlike rigid and non-tilting drive shaft connections, the connecting shaft of an articulated shaft tilts when the vehicle and / or drive wheels are under pressure, resulting in friction at the tilt joint, which leads to increased wear on the tilt joint. This wear can be avoided or reduced by cooling and / or lubricating the tilt joint with a cooling fluid, which can in particular be a lubricant such as lubricating oil. Furthermore, it has been found that when the articulated shaft is in normal operation, the connecting shaft tilts, and both the inner and outer tilt joints are subjected to stresses simultaneously and substantially equally. Therefore, it may be advantageous to fluidly connect the inner and outer tilt joints through a common cooling channel. Thus, the supplied cooling fluid can be fed sequentially or in parallel to both tilt joints and preferably discharged again through a common outlet, and / or fed to a radiator or heat exchanger for cooling, so that the cooling fluid can be reused in a closed loop.

[0008] The cooling channel spans the axial distance between the inner bevel joint on the transmission side and the outer bevel joint on the wheel side. However, for this purpose, instead of forming a radially outward-sealed pipe outside the connecting shaft, the cooling channel extends through the connecting shaft and inside it, making the connecting shaft hollow in this respect. Therefore, the cooling channel is radially formed within the cross-section of the material used for torque transmission in the connecting shaft. Consequently, compared to a solid shaft made of the same amount of material, the connecting shaft achieves a higher moment of inertia in the cross-section transverse to the torque transmission direction, thus enabling it to transmit torques relatively large relative to its own mass. This is particularly beneficial in electric vehicles, where full drive torque is available upon startup, ensuring reliable operation and low drive wear. By concentrating the material of the connecting shaft at a larger radius, a cavity is formed radially inside the connecting shaft—specifically, a continuous cavity in the axial direction—which can be used to form the cooling channel in a space-saving manner. In particular, the cavity can be large enough that the cooling channel can guide cooling fluid through the connecting shaft in both the first axial direction from the transmission to the drive wheel and the second axial direction from the drive wheel to the transmission. The cooling channels formed within the connecting shaft that transmits torque can be used to cool and lubricate the tilt joint in a space-saving manner without significantly adversely affecting the mechanical properties of the connecting shaft, thus achieving a hinged shaft that is both space-saving and low-wear.

[0009] The articulated shaft may include an inner housing portion on the transmission side, wherein the connecting shaft is obliquely received in an inner tilt joint. Specifically, the inner housing portion may be connected to or integrally formed with the output shaft of the differential gear. The articulated shaft may also include an outer housing portion on the wheel side, wherein the connecting shaft is obliquely received in an outer tilt joint. Specifically, the outer housing portion is part of the hub of the drive wheel. The articulated shaft may be tilted relative to the axle of the drive wheel, particularly a horizontally extending axle, and / or may be tilted relative to the drive wheel axle specifically defined by the connected differential gear, the tilting occurring at a deflection angle in the XY plane such that offsets in the vertical Z direction can be compensated for by the tilted connecting shaft.

[0010] The connecting shaft is configured to transmit a predetermined maximum driving torque such that the area moment of inertia of the connecting shaft material can transmit the torque occurring under these conditions without significant plastic deformation. The connecting shaft is specifically made of steel.

[0011] The drive wheel may include a hub, and a connecting shaft may engage with the hub via an outwardly tilting joint in a torque-transmitting manner. The drive wheel may roll on a surface to drive the motor vehicle by a torque applied at a given rotational speed.

[0012] Inward and / or outward tilting joints allow the connecting shaft to tilt, but torque transmission, particularly in a positive locking manner, is maintained throughout the entire deflection range of the connecting shaft. For example, the corresponding tilting joint can be configured with an arcuate tooth arrangement. The corresponding tilting joint may preferably include connecting elements, such as balls or cones, which are radially fixed to the inner and outer rings. The connecting elements can roll or slide correspondingly on the inner and outer rings during tilting movement and can abut against stops connected to the inner and outer rings tangentially, respectively, to enable the transmission of torque applied at different tilting positions of the corresponding tilting joint.

[0013] In particular, the cooling channel may be partially defined by the material of the connecting shaft. The cooling channel may extend to the outside of the connecting shaft, especially in the area of ​​the inclined joint.

[0014] The cooling fluid can be a liquid and / or gaseous medium capable of absorbing heat generated by friction in the bevel joint. In particular, the cooling fluid can simultaneously lubricate the bevel joint; in this respect, the cooling fluid possesses tribological properties and can form a friction-reducing lubricating film. The cooling fluid is particularly a lubricating oil. The heat absorbed by the cooling fluid can preferably be dissipated externally to the connecting shaft via natural or forced convection. Specifically, the cooling fluid can be cooled within a closed loop in a radiator or heat exchanger, such as a pre-heater cooled by an airflow.

[0015] Specifically, the connecting shaft is configured as a hollow shaft with a delivery pipe disposed within it to conduct cooling fluid. This is achieved, particularly through an outwardly inclined joint, by forming a fluid connection between the annular space formed between the outer side of the delivery pipe and the inner side of the connecting shaft and the interior of the delivery pipe, thus creating a cooling channel. The hollow interior of the connecting shaft can be divided into two flow cross-sections separated from each other by the delivery pipe, through which the cooling fluid can flow in different axial directions. Outside the delivery pipe, the cooling fluid can flow in the annular space in one axial direction, while inside the delivery pipe, it can flow in the opposite axial direction. Therefore, the connecting shaft can achieve both cooling fluid flow towards the outwardly inclined joint and cooling fluid flow away from the outwardly inclined joint. Compared to the connecting shaft, the delivery pipe does not need to transmit any driving torque, and therefore can be essentially unloaded during normal operation of the articulated shaft. Therefore, the delivery pipe can be designed to withstand relatively low loads and can have a correspondingly small wall thickness. For example, the delivery pipe can be made of sheet metal or plastic, particularly thermoplastic. The delivery pipe can have a rigid design, but it can also be formed as a flexible hose.

[0016] Preferably, at least one screw conveyor is provided in the annular space for conveying cooling fluid along the cooling channel. The screw conveyor is movably coupled to the connecting shaft and can rotate with the connecting shaft. Therefore, the screw conveyor can draw the cooling fluid into the screw conveyor's helical free space while having a motion component in the axial direction along the cooling channel, allowing the delivery pressure to be established within the cooling channel. In particular, the mass flow rate and / or delivery pressure can be increased as the rotational speed of the hinge shaft increases and thus the connecting shaft increases, resulting in particularly good cooling and / or lubrication effects even when the vehicle is traveling at high speeds.

[0017] Particularly preferably, in the common axial region of the screw conveyor, the connecting shaft includes a supply opening for supplying cooling fluid into the annular space and / or a discharge opening for removing cooling fluid from the annular space, wherein the discharge opening is particularly part of a nozzle for spraying the inner and / or outer inclined joints. The supply and / or discharge openings can form through openings through the wall of the connecting shaft, allowing cooling channels to extend within the connecting shaft. If the discharge opening, as part of a nozzle, sprays the associated inclined joint, preferably at least one connecting element of the associated inclined joint, then improved cooling and / or lubrication can be achieved.

[0018] Specifically, at least one nozzle body is provided on the outside of the connecting shaft in the axial direction, thereby forming a nozzle for spraying the inner and / or outer inclined joints. The nozzle body is constructed separately from the connecting shaft, and in particular, it can also be constructed separately from the delivery pipe. For example, the nozzle body is attached to the delivery pipe on the outside of the connecting shaft, allowing cooling fluid to be supplied to and / or removed from the inside of the delivery pipe. In this case, by applying the delivery pressure, the nozzle body can spray cooling fluid from the delivery pipe or another source through the nozzle onto the associated inclined joint, particularly the connecting element.

[0019] Preferably, the nozzle body is in fluid communication with the delivery pipe upstream of the nozzle. Therefore, cooling fluid can be sprayed from the delivery pipe through the nozzle body onto the associated inclined joint, particularly the outer inclined joint, preferably after the cooling fluid has already cooled the inner inclined joint upstream.

[0020] Alternatively, the nozzle body and / or another nozzle body divides the cooling channel into a first sub-channel and a second sub-channel, wherein the first sub-channel is configured specifically for cooling the inner inclined joint, and the second sub-channel is configured specifically for cooling the outer inclined joint. The nozzle body may divert a portion of the cooling fluid mass flow, particularly for cooling and / or lubricating the inner inclined joint, while another portion of the cooling fluid is preferably directed via a delivery conduit to the outer inclined joint for cooling and / or lubrication. These two streams from the two sub-channels can, in particular, be re-merged within a portion of the annular space, preferably by a common helical conveyor, and discharged again as a common, unified flow.

[0021] Particularly preferably, the inner and outer tilt joints are configured to allow the connecting shaft to form a deflection angle α relative to the horizontal plane, said deflection angle being 1° ≤ α ≤ 20°, particularly 2° ≤ α ≤ 15°, and preferably 5° ≤ α ≤ 10°. The tilt joints allow for a correspondingly larger tilt of the outer ring relative to the inner ring, particularly through the intermediate connecting element. The cooling and / or lubricating properties of the cooling fluid supplied through the cooling channels are sufficient to avoid or at least reduce unwanted wear at such deflection angles, thereby improving driving comfort.

[0022] On the other hand, a motor vehicle is involved, having a powertrain for transmitting drive torque, particularly electrically generated drive torque, to a left drive wheel and a right drive wheel. This powertrain includes a coupling unit, particularly a coupling unit configured as a differential gear, for driving the left drive wheel via a tiltable left hinge shaft and for driving the right drive wheel via a tiltable right hinge shaft, wherein the left hinge shaft and / or the right hinge shaft are configured as hinge shafts, which can be designed and further developed as described above. Cooling channels formed within the torque-transmitting coupling shaft can be used to cool and lubricate the tilting joint in a space-saving manner without significantly adversely affecting the mechanical properties of the coupling shaft, thus achieving a space-saving and low-wear coupling shaft.

[0023] Specifically, the coupling unit includes a supply line for supplying cooling fluid into the cooling channel and / or a discharge line for discharging cooling fluid from the cooling channel. The cooling fluid can also be used, in particular, to cool and / or lubricate the differential gears. Additionally, cooling fluid can be supplied to both the left and right hinge shafts via only one supply line and one discharge line in the coupling unit. Attached Figure Description

[0024] The invention will now be described with reference to the accompanying drawings and preferred exemplary embodiments, wherein the features described below may individually or in combination represent aspects of the invention, and the scope of protection is determined by the claims. The drawings show: Figure 1 : A schematic cross-sectional view of the first embodiment of the hinge shaft. Figure 2 : Figure 1 A schematic detail view of the inner end of the hinge shaft. Figure 3 : Figure 1 A schematic detail view of the outer end of the hinge shaft. Figure 4 : A schematic cross-sectional view of the second embodiment of the hinge shaft. Figure 5 : Figure 4 A schematic detail view of the inner end of the hinge shaft, and Figure 6 : Figure 4 A schematic detail of the outer end of the hinge shaft. Detailed Implementation

[0025] Figure 1The articulated shaft 10 shown can be used in motor vehicles, particularly electric vehicles, to transmit driving force from the powertrain to at least one drive wheel. For this purpose, the powertrain of the motor vehicle can have a coupling unit 12 to drive the articulated shaft 10. The coupling unit 12 is, for example, a differential gear, whose corresponding output shaft can be coupled to the articulated shaft 10. The articulated shaft 10 has an inner housing portion 14 into which driving force can be introduced. The applied torque can be rigidly locked from the inner housing portion 14 to the connecting shaft 20 via an inner tilting joint 16 having a ball-shaped coupling element 18. The connecting shaft 20 can then rigidly lock the torque to an outer housing portion 24, which can be connected to or integrally formed with the hub of the drive wheel via an outer tilting joint 22, which also has a ball-shaped coupling element 18.

[0026] like Figure 2 As shown, cooling fluid can be supplied through the inlet pipe 26 in the connecting unit 12. In the exemplary embodiment shown, the cooling fluid can be introduced into the nozzle body 28, specifically through the inner housing portion 14, which can then spray the cooling fluid onto the inner inclined joint 16 via the nozzle 30. The cooling fluid can then enter the hollow interior of the connecting shaft 14 through the supply opening 32, forming a cooling channel 34. The delivery pipe 36 is coaxially arranged with the connecting shaft 14 such that a portion of the cooling channel 34 is formed radially outside the delivery pipe 36 within an annular space 38 inside the connecting shaft 14, and another portion is formed radially inside the delivery pipe 36. In the exemplary embodiment shown, a screw conveyor 40 is also provided in the annular space to deliver the cooling fluid to the drive wheel through the supply opening 32. To prevent the cooling fluid from the inner inclined joint 16 from flowing away, a flexible bellows 42 is connected to the inner housing portion 14 and the connecting shaft 20. Additionally, the screw conveyor 40 has a central opening 44 into which one end of the conveying pipe 36 is inserted to discharge heated cooling fluid, particularly through a central channel 46 formed in the nozzle body 28, for example through a check valve 48, specifically for cooling. The cooled fluid can then be resupplyed within a closed loop through the inlet pipe 26.

[0027] like Figure 3As shown, cooling fluid supplied through the annular space 38 of the cooling channel 34 can be sprayed onto the outwardly inclined joint 22 through nozzles 30 in the discharge opening 50 of the connecting shaft 20. For this purpose, a screw conveyor 40 is also provided, the central opening 44 of which is used to accommodate the other end of the conveying pipe 36. The housing portion 24 encloses the outwardly inclined joint 22 and the axial end of the connecting shaft 20, so that the cooling fluid from the outwardly inclined joint 22 is conveyed into the interior of the conveying pipe 36 and thereby discharged toward the connecting unit 12 through the cooling channel 34.

[0028] exist Figure 4 In the embodiment of the hinge shaft 10 shown, compared to Figure 1 In the embodiment of the hinge shaft 10 shown, cooling fluid flows radially inward from the connecting unit 12 to the drive wheel via the delivery pipe 36 through the cooling channel 34, and flows radially outward from the drive wheel back to the connecting unit 12 via the annular space 38 through the cooling channel 34.

[0029] like Figure 5 As shown, for this purpose, only the nozzle body 28 is constructed differently. Cooling fluid supplied to the nozzle body 28 but not discharged through the central channel 46 of the nozzle body can be diverted within the nozzle body 28 into a first sub-channel 52 and a second sub-channel 54. The first sub-channel 52 can cool and lubricate the inner inclined joint 16 through the nozzle 30, while the second sub-channel 54 delivers a corresponding portion of the cooling fluid to the drive wheel via the delivery pipe 36. The heated cooling fluid returning from the drive wheel in the annular space 38 can be delivered to the connecting unit 12 via a screw conveyor 40 disposed radially inside the inner inclined joint 16. Here, the cooling fluid from the first sub-channel 52, after cooling and lubricating the inner inclined joint 16, can also be supplied to the screw conveyor 40 through the supply opening 32 in the connecting shaft 20, so that the two diverted streams of cooling fluid re-merge in the screw conveyor 40. Therefore, the inner inclined joint 16 and the outer inclined joint 22 can be connected in parallel rather than in series for cooling and lubrication by the cooling fluid.

[0030] like Figure 6 As shown, the nozzle body 28 can be connected to the axial end of the delivery pipe 36, particularly at the end opposite to the delivery pipe 36 at the center opening 44 of the screw conveyor 40 located there. The outwardly inclined joint 22 can be cooled and lubricated by the nozzle 30 of the nozzle body 28, wherein the heated cooling fluid can enter the annular space 38 of the cooling channel 34 through the supply opening 32 in the connecting shaft 20 for delivery back to the connecting unit 12.

Claims

1. A hinge shaft (10) for transmitting the driving torque of a motor vehicle to at least one drive wheel, said hinge shaft having: A connecting shaft (20) is used to connect the transmission to the drive wheel in a manner that transmits torque; An inward tilting joint (16) on the transmission side is used to connect the connecting shaft (20) to the transmission in a tilting and torque-transmitting manner; An outward tilting joint (22) on the wheel side is used to connect the connecting shaft (20) to the drive wheel in a tilting and torque-transmitting manner; And a cooling channel (34) through the connecting shaft (20), which is used to fluidly connect the inner inclined joint (16) to the outer inclined joint (22) for the flow of cooling fluid.

2. The hinge shaft (10) according to claim 1, wherein the connecting shaft (20) is constructed as a hollow shaft and a delivery pipe (36) is disposed within the connecting shaft (20) to conduct the cooling fluid, wherein a fluid connection is formed between the annular space (38) formed between the outer side of the delivery pipe (36) and the inner side of the connecting shaft (20) and the interior of the delivery pipe (36), thereby realizing the cooling channel (34).

3. The hinge shaft (10) according to claim 2, wherein at least one spiral conveyor (40) is provided in the annular space (38) for conveying the cooling fluid along the cooling channel (34).

4. The articulated shaft (10) according to claim 3, wherein in the common axial region of the screw conveyor (40), the connecting shaft (20) has a supply opening (32) for supplying the cooling fluid into the annular space (38) and / or a discharge opening (50) for discharging the cooling fluid from the annular space (38).

5. The hinge shaft (10) according to any one of claims 2 to 4, wherein at least one nozzle body (24) is provided outside the connecting shaft (20) in the axial direction for forming a nozzle (30) for spraying the inner tilt joint (16) and / or the outer tilt joint (22).

6. The hinge shaft (10) according to claim 5, wherein the nozzle body (24) is in fluid communication with the delivery pipe (36) upstream of the nozzle (30).

7. The hinge shaft (10) according to claim 5 or 6, wherein the nozzle body (24) divides the cooling channel (34) into a first sub-channel (52) and a second sub-channel (54), wherein the first sub-channel (52) is configured to specifically cool the inner tilt joint (16) and the second sub-channel (54) is configured to specifically cool the outer tilt joint (22).

8. The hinge shaft (10) according to any one of claims 1 to 7, wherein the inner tilt joint (16) and the outer tilt joint (22) are configured to allow the connecting shaft (20) to form a deflection angle α relative to the horizontal plane, the deflection angle being 1° ≤ α ≤ 20°, particularly 2° ≤ α ≤ 15°, and preferably 5° ≤ α ≤ 10°.

9. A motor vehicle having a powertrain for transmitting drive torque, particularly electrically generated drive torque, to a left drive wheel and a right drive wheel, wherein the powertrain includes a coupling unit (12), particularly a coupling unit configured as a differential gear, for driving the left drive wheel via a tiltable left hinge shaft and for driving the right drive wheel via a tiltable right hinge shaft, wherein the left hinge shaft and / or the right hinge shaft is configured as a hinge shaft (10) according to any one of claims 1 to 8.

10. The motor vehicle according to claim 9, wherein the coupling unit (12) includes a supply line (26) for supplying the cooling fluid to the cooling passage (34) and / or a discharge line for discharging the cooling fluid from the cooling passage (34).

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