Drive arrangement

Abstract

The invention relates to a drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) having a stator (3) and a rotor (4) which can be connected or is connected to a rotor shaft (5) having an output, and a temperature control device (7) which is designed to conduct temperature control fluid into rotor channels (8, 9) extending through the rotor (4) in the axial direction, wherein the temperature control device (7) has a feed shaft (12) which is arranged radially, in particular coaxially, within the rotor (4), is separate from the rotor shaft (5) and has at one first feed opening (14) at a first feed axial position (13) and at least one second feed opening (16) at a second feed axial position (15), wherein the rotor (4) has circumferentially distributed first receiving openings (17) associated with the at least one first feed opening (15) at a first receiving axial position (18) and circumferentially distributed second receiving openings (19) associated with the at least one second feed opening (15) at a second receiving axial position (18), wherein the first receiving openings (17) are connected to first rotor channels (8) and the second receiving openings (19) are connected to second rotor channels (9).

Description

[0001] Drive arrangement

[0002] The invention relates to a drive arrangement, in particular for a motor vehicle, comprising an electric machine with a stator and a rotor that can be connected or connected to a rotor shaft with an output and a temperature control device designed to guide temperature control fluid into rotor channels extending axially through the rotor.

[0003] Drive arrangements for motor vehicles, comprising an electric machine with a stator and a rotor rotating relative to the stator, are generally known from the prior art. The electric machine can be used as a drive device, generating a torque that can be transmitted via a rotor shaft connected to the rotor to an output of the motor vehicle, for example, to at least one wheel of the motor vehicle. It is further known from the prior art that such electric machines typically require temperature control during operation, for example, preheating or cooling. In particular, such a temperature control device dissipates heat generated during operation by circulating temperature control fluid through the electric machine.

[0004] For example, it is known to supply the temperature control fluid, such as coolant, to the rotor shaft, whereby the flow paths of the coolant within the rotor shaft can be divided and thus directed specifically to the rotor. However, this is disadvantageous in that the rotor of the electric machine and the associated rotor shaft have a comparatively large diameter and, compared to other gear components, operate at very high speeds, meaning that the influence of centrifugal force on the temperature control fluid is also very high.

[0005] This can lead to significant fluctuations in the ratio of flow excitation by rotation to flow resistance in the channels at high speeds or high centrifugal forces. The distribution of the temperature control fluid, or the supply of the temperature control fluid to the electric machine, becomes highly dependent on the rotational speed, making a uniform supply across all speed ranges difficult to achieve. Furthermore, drag losses are increased due to the conditions present in the rotor shaft and the resulting swirl energy.

[0006] The invention is based on the objective of providing an improved drive arrangement in which, in particular, the supply of temperature control fluid is improved.

[0007] The problem is solved by a drive arrangement having the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0008] As described, the invention relates to a drive arrangement, specifically for a motor vehicle. The drive arrangement comprises at least one temperature control unit and an electric motor. The temperature control unit is designed to regulate the temperature of the electric motor. For this purpose, the temperature control unit circulates a temperature control fluid, for example, a liquid, specifically oil or water, through the electric motor, specifically through the rotor. The temperature control unit can be used, in particular, to cool the electric motor. The rotor has several rotor channels extending axially through it, through which the temperature control fluid can be guided. The temperature control fluid therefore exchanges heat with the rotor as it flows through the rotor channels.

[0009] The invention is based on the finding that the temperature control device has a radially, in particular coaxially, arranged within the rotor, separate from the rotor shaft, which has at least one first feed opening at a first feed axial position and at least one second feed opening at a second feed axial position, wherein the rotor has first receiving openings distributed in the circumferential direction, the first receiving opening being associated with at least one first feed opening being at a first receiving axial position and the second receiving opening being associated with at least one second feed opening being at a second receiving axial position, wherein the first receiving openings are connected to first rotor channels and the second receiving openings are connected to second rotor channels.

[0010] In other words, the invention proposes that the temperature control fluid is not supplied to the rotor via the rotor shaft, as is known from the prior art, but rather that a separate supply shaft is provided, which is designed separately from the rotor shaft and through which the temperature control fluid is introduced into the rotor. The supply shaft can thus guide the temperature control fluid axially into the rotor, with the fluid being directed from the supply shaft, namely via the supply openings, to the rotor.

[0011] The supply shaft can therefore operate at a significantly lower rotational speed than the rotor or the rotor shaft connected to the rotor. Since the supply shaft lies radially inside the rotor or engages axially with the rotor shaft, the supply openings in the supply shaft are also arranged on a significantly smaller diameter or radius than openings in the rotor shaft could be. This means that the rotational speed of the electric machine, especially the rotation of the rotor, has a significantly smaller or no influence on the distribution of the temperature control fluid. This also reduces drag losses due to lower swirl energy in the supply shaft.Suction and pressure effects do not dominate the supply of the temperature control fluid via the feed shaft, thus ensuring a uniform supply of temperature control fluid to the electric machine under all operating conditions.

[0012] As described, the temperature control fluid is introduced into the rotor axially via the supply shaft, specifically radially inside, and in particular radially within the rotor shaft. The supply shaft is thus designed to provide the temperature control fluid, and the rotor is designed to distribute the supplied temperature control fluid to the rotor channels. Specifically, the temperature control fluid is introduced axially into the rotor by the supply shaft, namely on or near the rotor's axis of rotation. The basic distribution of the temperature control fluid, or its provision at different positions, is therefore handled by the supply shaft. Temperature control fluid is provided by the supply shaft at the first axial supply position, namely through the at least one first supply opening. Furthermore, the temperature control fluid is provided by the supply shaft at the second axial supply position, namely through the at least one second supply opening.

[0013] From the supply openings, the temperature control fluid can flow radially towards the rotor and then, via the receiving openings provided in the rotor, into the rotor channels. In other words, the distribution into the rotor channels is carried out via the receiving openings, with the supply shaft delivering the temperature control fluid to the receiving openings. Specifically, temperature control fluid exiting the first supply opening at the first axial position reaches the at least one receiving opening at that same position and from there flows into the first rotor channels, or into one of the first rotor channels. Similarly, temperature control fluid exiting the second supply opening at the second axial position reaches the at least one second receiving opening at that same position and from there flows into the second rotor channels, or into one of the second rotor channels.The first feed axial position can be identical to the first receiving axial position, or the first feed axial position can be axially located within the range of the first receiving axial position. Likewise, the second feed axial position can be identical to the second receiving axial position, or the second feed axial position can be axially located within the range of the second receiving axial position.

[0014] In a further development of the drive arrangement, the first and second rotor channels can be arranged alternately in the circumferential direction. This alternating arrangement of the different rotor channels, which are connected to the different supply or receiving openings, results in improved thermal distribution within the electric machine. In other words, the flow and flow direction of the temperature control fluid through the rotor channels, supplied from different openings, alternates in the circumferential direction. This homogenizes the temperature field across the rotor. Furthermore, the drive arrangement can be configured with a temperature control device designed for counter-rotating flow through the first and second rotor channels.As previously described, the temperature control fluid is supplied at different axial positions, namely at the first supply axial position and the second supply axial position. Similarly, the fluid enters the rotor channels at different axial positions, namely at the first receiving axial position and the second receiving axial position. These different axial positions are located at opposite ends of the rotor, specifically opposite each other in the axial direction. For example, the first rotor channels are filled with temperature control fluid at a first axial end, namely through the at least one first receiving opening, and the second rotor channels are filled with temperature control fluid at a second axial end of the rotor, namely through the at least one second receiving opening.

[0015] Due to the counter-rotating flow and the alternating circumferential orientation of the first and second rotor channels, the temperature distribution across the rotor is uniform. This ensures that the "cold side," or the inflow of the cooling fluid, is located on the first side of the rotor when the first rotor channels are flowing through, and on the second side when the second rotor channels are flowing through. Consequently, the cooling fluid exiting the rotor channels and being flung onto the winding heads of the electric machine is also heated uniformly. Compared to a unidirectional flow from a single side, this circumferential alternation of the flow direction results in a more uniform temperature distribution.

[0016] As described earlier, the feed shaft is separate from the rotor shaft. This means that there can be fundamentally different rotational speeds between the feed shaft and the rotor shaft, and therefore the current operating conditions have less influence on the supply of the temperature control fluid from the feed shaft. Specifically, the feed shaft can be designed to rotate more slowly or be stationary relative to the rotor. Since the feed shaft is radially internal to the rotor, it also has a smaller diameter than the rotor or rotor shaft. Because the feed shaft rotates more slowly than the rotor or rotor shaft, the influence of the rotational movement on the temperature control fluid supplied by the feed shaft is significantly less than it would be if the temperature control fluid were supplied directly into the rotor shaft.For example, the rotor can rotate at several thousand revolutions / min, while the feed shaft can rotate or remain stationary, for example, in a range of <1500rpm, in particular <1000rpm.

[0017] The electric machine, or its rotor, can generally be configured coaxially or parallel to the output shaft of the electric machine. In one embodiment of the drive arrangement, the feed shaft can be designed as an output shaft, connected to an output shaft, or non-rotatably connected to a housing of the drive arrangement. As described, the feed shaft can rotate at a slower rate than the rotor or, in a special case, be stationary, i.e., non-rotatably connected to a housing of the drive arrangement. This results in the rotational speed of the feed shaft being zero or lower than the rotational speed of the rotor in any operating state, particularly in any operating state where the rotor is rotating. If the feed shaft is designed as an output shaft or connected to an output shaft, for example, the usual wheel rotational speeds are present at the feed shaft.In contrast, the rotor of the electric machine rotates significantly faster, for example at several thousand revolutions per minute. Accordingly, the supply of the temperature control fluid can be designed to be more stable across all operating conditions, since suction and pressure effects generated by the rotation of the rotor have less of an impact on the distribution of the temperature control fluid.

[0018] In one embodiment of the invention, the supply openings extend radially through the supply shaft, and the receiving openings extend radially through the rotor shaft or a shaft element connected to the rotor shaft. The supply openings can, for example, be configured as holes or bores in the supply shaft. This makes it possible, for example through a central bore, to guide temperature control fluid axially through the supply shaft, which then exits radially through the supply openings. From there, the temperature control fluid flows radially through the receiving openings in the rotor shaft or shaft element into the respective rotor channels.

[0019] The first and second receiving ports can be alternately opened and closed by rotating the rotor. For example, at least one receiving port is provided at each of two axial positions, namely the feed axial positions, in the feed shaft. Depending on the position of the rotor relative to the feed shaft, either the first or the second receiving port is opened. This allows the temperature control fluid to enter the first rotor channels either through the first receiving port(s) or through the second receiving port(s). Due to the rotational movement, temperature control fluid is thus alternately supplied to the first and second rotor channels. Because of the design described herein, the pressure in the temperature control fluid will dominate against centrifugal forces from the rotation.As a result, the distribution of the temperature control fluid across the speed range of the electric machine does not change, or does not change significantly.

[0020] In a further embodiment of the drive arrangement, at least one fluid collection device is provided at the first and / or second receiving openings. This device is designed to capture the temperature control fluid discharged from the supply openings. The fluid collection device can, for example, be configured as a collecting edge, a trapping edge, or a trapping geometry. The fluid collection device is designed to collect, capture, or accumulate the temperature control fluid in front of the receiving openings or the receiving opening to which the fluid collection device is assigned. The fluid collection device allows the temperature control fluid exiting the supply openings to be selectively collected in the flow direction in front of the receiving openings, thus ensuring the supply to the rotor channels and the controlled flow of the temperature control fluid within the electric machine.

[0021] Furthermore, another drive arrangement, not shown in the following drawings, is proposed, in particular for a motor vehicle, comprising an electric machine with a stator and a rotor that can be connected or connected to a rotor shaft with an output and a temperature control device designed to guide temperature control fluid into rotor channels extending axially through the rotor.The drive arrangement is characterized in that the temperature control device has a feed shaft arranged radially, in particular coaxially, within the rotor, separate from the rotor shaft, and which has at least one first feed opening at a first feed axial position. The rotor has first receiving openings distributed in the circumferential direction, each associated with at least one first feed opening, at a first receiving axial position. The first receiving openings are connected to first rotor channels, and the feed shaft is designed to rotate or be stationary relative to the rotor. In this drive arrangement, the feed shaft can also be designed as an output shaft, be connected to an output shaft, or be rotationally fixed to a housing of the drive arrangement.Similarly, at least one first feed opening can extend radially or axially through the feed shaft, and the first receiving openings can extend radially through the rotor shaft or a shaft element connected to the rotor shaft. Further features described in relation to the first drive arrangement can also be implemented in the further drive arrangement described here, for example, the coupling of the feed shaft via a gearbox or a differential.

[0022] In addition to the drive arrangement, the invention relates to a motor vehicle comprising a drive arrangement as previously described. All advantages, details, and features described with respect to the drive arrangement are fully transferable to the motor vehicle.

[0023] The invention is explained below with reference to exemplary embodiments and the figures. The figures are schematic representations and show:

[0024] Fig. 1 shows a schematic representation of a drive arrangement according to a first embodiment; Fig. 2 shows a schematic representation of a drive arrangement according to a second embodiment;

[0025] Fig. 3 shows a schematic representation of an electrical machine in a first sectional view;

[0026] Fig. 4 shows the electric machine of Fig. 3 in a second sectional view; and

[0027] Fig. 5 shows a schematic representation of a distribution of rotor channels in an electric machine.

[0028] Fig. 1 shows a schematic representation of a drive arrangement 1, which is intended, for example, for driving a motor vehicle (not shown in detail). The drive arrangement 1 comprises an electric machine 2, which includes a stator 3 and a rotor 4. The schematic representation shows that the rotor 4 is connected to a gearbox 25 or a differential 26 via a rotor shaft 5. Fig. 1 thus shows an axially parallel arrangement of the electric machine 2, in which it is arranged axially parallel to the gearbox 25 or differential 26. In other words, an output shaft 6 is arranged parallel to the rotor shaft 5, but the two shafts are not coaxial with each other.

[0029] Fig. 2 also shows a schematic representation of a drive arrangement 1 according to a further embodiment. In contrast to the representation in Fig. 1, the electric machine 2 in the drive arrangement 1 in Fig. 2 is designed coaxially, i.e., the axes of rotation of the gearbox 25 or differential 26, in particular the output shaft 6 and the rotor shaft 5, are identical, or rather, both axes of rotation coincide. The basic design of the drive arrangement 1 described herein can be applied to both variants shown in Figs. 1 and 2 and is therefore described analogously below. In addition to the components explicitly described, the drive arrangement 1 can include further components, for example, a pump 22, a filter 23, a heat exchanger 24, and an oil sump 27 or an oil return line.The drive arrangement 1 additionally includes a temperature control device 7, which is designed to supply a temperature control fluid, for example a liquid, specifically water or oil, to the rotor 4 of the electric machine 2 in order to temperature-control the rotor 4. As indicated by arrows representing the circuit of the temperature control fluid in the drive arrangement 1, the stator 3 or other components can also be temperature-controlled. In this description, temperature control refers to cooling or heating.

[0030] The temperature control device 7, as shown, for example, in Figures 3 and 4, guides the temperature control fluid axially through the rotor 4, namely through rotor channels 8 and 9. The rotor channels 8 and 9 extend axially through the rotor 4, from a first axial end face 10 to a second axial end face 11. The temperature control device 7 has a feed shaft 12 for supplying the temperature control fluid, through which the fluid is introduced into the rotor 4. As can be seen in Figures 3 and 4, the temperature control fluid can, for example, be supplied from the output side. The feed shaft 12 extends within the rotor shaft 5 and into the rotor 4, thus engaging axially within the rotor 4 and lying sectionally within the rotor 4 in the radial direction.

[0031] The feed shaft 12 has at least one first feed opening 14 at a first feed axial position 13 and at least one second feed opening 16 at a second feed axial position 15. The two feed axial positions 13, 15, and thus also the at least two feed openings 14, 16, are therefore axially spaced apart from each other. Temperature control fluid dispensed from the first feed opening 14 is fed to at least one first receiving opening 17, which is arranged at a first receiving axial position 18. Similarly, temperature control fluid dispensed from the second feed opening 16 is fed to at least one second receiving opening 19, which is arranged at a second receiving axial position 20.The first feed axial position 13 can be identical to or in the vicinity of the first receiving axial position 18, and / or the second feed axial position 15 can be identical to or in the vicinity of the second receiving axial position 20, particularly in a range of 1 mm to 50 mm. As can be seen in Figures 3 and 4, the receiving openings 17 and 19 are connected to the rotor channels 8 and 9. Specifically, the first receiving opening 17 is connected to the first rotor channels 8, and the second receiving opening 19 is connected to the second rotor channels 9. This allows the rotor 4 to be subjected to counter-rotating axial flow, as indicated by arrows in Figures 3 and 4. The feed shaft 12 enables the temperature control fluid to be supplied radially within the rotor 4, with distribution to the rotor channels 8 and 9 being carried out by the receiving openings 17 and 19, which are located on the rotor side.

[0032] Since the feed shaft 12 is stationary or rotates at a significantly lower speed than the rotor 4 and also has a significantly smaller diameter, the effects on the temperature control fluid during feeding, for example at rotational speed, are less pronounced than when feeding into the rotor shaft 5 or the rotor 4. In the embodiment according to Fig. 1, where the axis-parallel arrangement of the electric machine 2 is chosen, the feed shaft 12 can be designed as a housing-fixed shaft, i.e., that the feed shaft 12 is stationary relative to the rotor 4. Here, the feed shaft 12 can be rotationally fixed to the housing of the drive assembly 1.

[0033] Alternatively, as shown in Fig. 2, the feed shaft 12 can be coupled to or integrated within the output shaft 6. In either case, the feed shaft 12 does not rotate fixedly with the rotor 4, but is either stationary or rotates significantly slower than the rotor 4. If the feed shaft 12 is integrated into or formed by the output shaft 6, the latter exhibits typical wheel speeds. The rotational speed of the rotor 4 is known to be in a significantly higher speed range, so that, due to the smaller diameter and slower rotational speed of the feed shaft 12, drag losses as well as suction and pressure effects acting on the temperature control fluid are significantly reduced. This ensures that the supply of the temperature control fluid dominates the distribution of the temperature control fluid in the electric machine 2 and that this is not superimposed or overridden by centrifugal forces and the like in certain speed ranges.Figures 3 and 4 further illustrate how the temperature control fluid exiting the feed openings 14 and 16 can be alternately received in the receiving openings 17 and 19. For example, Figures 3 and 4 depict different states of the rotor 4, which can be transitioned into one another by rotating the rotor 4 about its axis of rotation. According to the current position of the rotor 4 about its axis of rotation, the individual receiving openings 17 and 19 are therefore superimposed, so that the fluid is fed into the individual rotor channels 8 and 9, for example alternately, as the rotor 4 rotates.

[0034] Figures 3 and 4 show a fluid collection device 21, which is arranged at the first receiving openings 17 and the second receiving openings 19, respectively. The fluid collection device 21 captures or traps the temperature control fluid before it enters the receiving openings 17 and 19. This ensures a more reliable supply of temperature control fluid during the operation of the electric machine 2.

[0035] Fig. 5 shows a schematic representation of the distribution or flow of the temperature control fluid through the rotor 4. A three-pole electric machine 2 is shown as an example, which has three rotor channels 8, 9, namely three first rotor channels 8 and three second rotor channels 9, which alternate in the circumferential direction of the rotor 4 and thus allow counter-rotating flow through the rotor 4. This results in a particularly uniform temperature distribution in the rotor 4 of the electric machine 2. The number of poles or pole pairs, as well as the number of rotor channels 8, 9 and the number of groups of rotor channels, and the number of supply openings 14, 16 and the number of receiving openings 17, 19, are arbitrarily selectable.

[0036] The advantages, details, and features shown in the individual embodiments can be combined, interchanged, and transferred to one another as desired. Reference numerals

[0037] Drive arrangement electric machine stator

[0038] rotor

[0039] Rotor shaft

[0040] Output shaft

[0041] Temperature control device, 9 Rotor channel 0, 11 End surface 2 Feed shaft 3 First feed axial position 4 First feed opening 5 Second feed axial position 6 Second feed opening 7 First receiving opening 8 First receiving axial position 9 Second receiving opening 0 Second receiving axial position 1 Fluid collection device 2 Pump 3 Filter 4 Heat exchanger 5 Gearbox 6 Differential 7 Oil sump

Claims

Patent claims 1. Drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) with a stator (3) and a rotor (4) connectable or connected to a rotor shaft (5) with an output, and a temperature control device (7) configured to guide temperature control fluid into rotor channels (8, 9) extending axially through the rotor (4), characterized in that the temperature control device (7) has a radially, in particular coaxially, arranged within the rotor (4) and separate from the rotor shaft (5), which has at least one first supply opening (14) at a first supply axial position (13) and at least one second supply opening (16) at a second supply axial position (15), wherein the rotor (4) has first receiving openings (17) associated with the at least one first supply opening (15) at a first receiving axial position (18) and distributed circumferentially.the second receiving openings (19) associated with at least one second feed opening (15) at a second receiving axial position (18), wherein the first receiving openings (17) are connected to first rotor channels (8) and the second receiving openings (19) are connected to second rotor channels (9).

2. Drive arrangement (1 ) according to claim 1 , characterized in that the feed shaft (12) is designed to provide the temperature control fluid and the rotor (4) is designed to distribute the provided temperature control fluid to the rotor channels (8, 9).

3. Drive arrangement (1 ) according to claim 1 or 2, characterized in that the first rotor channels (8) and the second rotor channels (9) are arranged alternately in the circumferential direction.

4. Drive arrangement (1 ) according to one of the preceding claims, characterized in that the temperature control device (7) is designed for counter-rotating flow through the first rotor channels (8) and the second rotor channels (9).

5. Drive arrangement (1 ) according to one of the preceding claims, characterized in that the feed shaft (12) is designed to rotate more slowly or to be stationary relative to the rotor (4).

6. Drive arrangement (1 ) according to one of the preceding claims, characterized in that the feed shaft (12) is designed as an output shaft (6) or is connected to an output shaft (6) or is rotationally fixed to a housing of the drive arrangement (1 ).

7. Drive arrangement (1 ) according to one of the preceding claims, characterized in that the feed openings (14, 16) extend radially through the feed shaft (12) and the receiving openings (17, 19) extend radially through the rotor shaft (5) or a shaft element connected to the rotor shaft (5).

8. Drive arrangement (1 ) according to one of the preceding claims, characterized in that the first receiving openings (17) and the second receiving openings (19) are alternately opened and closed by a rotation of the rotor (4).

9. Drive arrangement (1 ) according to one of the preceding claims, characterized in that at least one fluid capture device (21 ) is arranged at the first receiving openings (17) and / or the second receiving openings (19), which is designed to capture temperature control fluid discharged from the supply openings (14, 16).

10. Drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) with a stator (3) and a rotor (4) connectable or connected to a rotor shaft (5) with an output and a temperature control device (7) configured to guide temperature control fluid into rotor channels (8, 9) extending axially through the rotor (4), wherein the temperature control device (7) has a supply shaft (12) arranged radially, in particular coaxially, within the rotor (4) and separate from the rotor shaft (5). having at least one first feed opening (14) at a first feed axial position (13), wherein the rotor (4) has circumferentially distributed first receiving openings (17) associated with at least one first feed opening (14) at a first receiving axial position (18), wherein the first receiving openings (17) are connected to first rotor channels (8), characterized in that the feed shaft (12) is designed to rotate or be stationary relative to the rotor (4).

11. Drive arrangement (1) according to claim 10, characterized in that the feed shaft (12) is designed as an output shaft (6) or is connected to an output shaft (6) or is rotationally fixed to a housing of the drive arrangement (1).

12. Drive arrangement (1 ) according to claim 10 or 11 , characterized in that the at least one first feed opening (14) extends in the radial direction or in the axial direction through the feed shaft (12) and the receiving openings (17) extend in the radial direction through the rotor shaft (5) or a shaft element connected to the rotor shaft (5).

13. Motor vehicle comprising a drive arrangement (1) according to any of the preceding claims.

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