ELECTRIC ROTARY MACHINE AND DRIVE ASSEMBLY

Description

[0001] The invention relates to an electric rotary machine and a drive arrangement for a motor vehicle.

[0002] Various electric drive devices are known from the prior art and are used in drive systems for motor vehicles. Such electric drive devices typically comprise an electric rotary machine with a rotor rotatable about a rotational axis, a stator arranged statically with respect to the rotor, and a housing in which the electric rotary machine is arranged or which is formed by the electric rotary machine, for enclosing the rotor. It is known to provide cooling for the stator and / or rotor of the electric rotary machine in order to increase efficiency.

[0003] DE 10 2015 015 797 A1 discloses an electric machine with a rotor and a stator. The stator comprises at least one winding, which has at least one surface facing the rotor, which can be exposed to a cooling fluid sprayed radially outward from the rotor by rotating the rotor to cool the winding.

[0004] EP 3 059 837 A1 describes a method for surface cooling of at least part of an electrical machine and a cooling device for implementing the method. The cooling device is designed to form a high-pressure flow and a low-pressure flow to generate a coolant flow. For this purpose, the cooling device comprises a nozzle that generates the high-pressure flow, wherein the high-pressure flow is designed to run along a surface to be cooled of a rotor of the electrical machine using the Coanda effect and to carry a low-pressure flow according to the injection principle.

[0005] WO 2016 132 060 A1 describes an electric rotary machine having a stator with a stator body and a distribution circuit for receiving a cooling fluid for cooling the electric rotary machine.

[0006] The distribution circuit is designed to direct a cooling fluid into an interior of the electric rotating machine, in which the stator is located. For this purpose, the distribution circuit has precisely one opening, which faces a side surface of the stator body, so that the cooling fluid can be directed directly to the stator body.

[0007] JP 2016 149 900 A discloses a cooling structure comprising an electric rotary machine, a circulation path, a fluid tank, a return channel and a valve device.

[0008] The electric rotary machine comprises a rotor and a stator, wherein the rotor is arranged in a rotor chamber and the stator is arranged in a stator chamber, and these two chambers are separated from each other in a fluid-tight manner by a partition wall. The circulation path connects the fluid tank to the stator chamber, and the return channel also connects the fluid tank to the stator chamber. The valve device is configured to control the volume flow in the return channel. The valve device controls the flow depending on the fluid pressure prevailing in the stator chamber.

[0009] DE 10 2016 103 408 A1 teaches a stator of an electric motor, comprising a stator core, a coil wound around teeth of the stator core, an outer cylinder surrounding the teeth at their yoke, and a heat-conducting part in contact with an inner circumferential surface of the outer cylinder and a coil end of the coil.

[0010] This design allows part of the heat generated at the coils during motor operation to be conducted through the heat-conducting part to the outer cylinder, and then dissipated from the outer cylinder to the outside air. The motor coil is cooled accordingly via the heat-conducting part.

[0011] The document US 8 348 727 B2 discloses a fan or ventilator for a power tool, in particular an angle grinder.

[0012] Particularly efficient cooling of electric rotating machines is typically achieved through fluid cooling. Oil is typically used as the cooling fluid, which is directed to the rotor and / or stator to dissipate heat. The oil is typically directed to the rotor and / or stator using one of two methods. A distribution device can be connected to a rotating component and, upon rotation, utilizing centrifugal force, can project the oil onto the rotor and / or stator.

[0013] Alternatively, the distribution device is mounted on a stationary component to spray the oil onto the rotor and / or stator in a nozzle-like manner. However, if the distribution device is configured as a nozzle, only a specific section of the circumference of the rotor and / or stator is sprayed, so several nozzles must be provided distributed around the circumference to ensure uniform cooling of the stator.

[0014] However, centrifugal cooling only distributes the cooling oil or fluid across the entire circumference as long as the fluid-carrying component is rotating. This means that when the fluid-carrying component is stationary, the fluid is not further distributed but is only cooled locally, and overheating can occur locally at the uncooled points. Furthermore, the design of the fluid distribution in the rotating fluid-carrying component is complex, depending on the speed and the prevailing fluid pressure, especially when multiple fluid dispensing devices are provided that are fluidically interconnected.

[0015] Based on this, the present invention is based on the object of providing an electric rotary machine and a drive arrangement equipped therewith, which realize a large-area cooling of the electric rotary machine in a structurally simple and cost-effective manner.

[0016] The object is achieved by the electric rotary machine according to the invention as defined in claim 1. Advantageous embodiments of the electric rotary machine are defined in subclaims 2 to 7. In addition, a drive arrangement for a motor vehicle, which comprises the electric rotary machine, is provided as defined in claim 8.

[0017] The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures can also be used to comprise additional embodiments of the invention.

[0018] In the context of the present invention, the terms "axial" and "radial" always refer to the axis of rotation of the distribution element.

[0019] The invention relates to an electric rotary machine with a rotor rotatable about a rotational axis and a stator arranged statically with respect to the rotor. The electric rotary machine further comprises at least one statically fixed fluid supply device and a distribution element fluidically connected to the fluid supply device, rotatable relative to the fluid supply device, and a component that is substantially rotationally symmetrical about its rotational axis. The fluid supply device has a flow channel with an outlet for discharging a cooling fluid volume flow in an outlet direction.An axis of rotation of the distribution element is arranged in relation to the outlet in such a way that the outlet direction runs tangentially to a circumference of the distribution element, so that the distribution element can be tangentially flowed against by the cooling fluid volume flow emerging from the outlet and the distribution element can be set in rotation by the flow, whereby the cooling fluid can be distributed around the axis of rotation of the distribution element while being carried along by the distribution element.

[0020] In this way, the cooling fluid can be guided or distributed to at least one component of the electric rotating machine, in particular to windings or winding heads of the stator windings.

[0021] In particular, it is provided that the outlet runs substantially perpendicular to the rotational axis of the rotor, and the rotational axis of the distribution element runs parallel to the rotational axis of the rotor.

[0022] The outlet and the distribution element can be arranged and configured such that the cooling fluid volume flow is directed toward a partial circumference of the distribution element. This means that the vector of the cooling fluid volume flow does not act radially on the outside of the distribution element, but rather on the axial surface of the distribution element, yet still not radially with respect to the rotational axis of the distribution element.

[0023] In particular, the distribution element is a disc or a sleeve.

[0024] The distribution element can have at least one opening leading radially outward on its circumference. This means that in one embodiment of the distribution element, an opening extends radially outward from a central axial passage of the distribution element to promote centrifugal force-induced conveyance of the cooling fluid. Furthermore, an edge or surface bounding this opening serves as a driving element during the tangential flow to the distribution element, so that it can be set into rotation not only due to friction, but also due to the hydrodynamic pressure acting on this edge or surface.

[0025] In particular, such an opening leading radially outwards can be formed by a slot extending over the entire axial length in a distribution element designed as a disc or sleeve, or can also be formed as a bore in a distribution element designed as a sleeve.

[0026] Furthermore, the distribution element can have at least one entraining element, which can be tangentially exposed to the cooling fluid volume flow and thus absorbs a tangentially acting force on the distribution element due to the effect of the hydrodynamic pressure of the cooling fluid. Such a entraining element can be the aforementioned edge or surface of the radially outward-facing opening, or else another or further element arranged on an axial end face of the distribution element facing the outlet, or else an element arranged in a central axial passage of the distribution element, where it is subjected to the hydrodynamic pressure of the cooling fluid. A entraining element arranged at this position can be realized in particular as a groove formed in the distribution element and extending essentially parallel to the axis.

[0027] The fluid supply device can be arranged on the stator or formed by it. Alternatively, the fluid supply device is arranged on a housing of the electric rotary machine or formed by it.

[0028] According to the invention, the flow channel is formed at least in sections by a longitudinal bore of a screw screwed into a statically fixed element of the electric rotary machine, wherein the outlet is formed in the screw extending from the longitudinal bore. The flow channel runs in particular parallel to the rotation axis of the rotor. In this embodiment, the distribution element is located in the axial direction between the statically fixed element and a screw head of the screw with its central axial passage on a shaft of the screw, wherein there is sufficient axial play between the statically fixed element and the distribution element on the one hand and between the distribution element and the screw head on the other hand, so that the distribution element can rotate around the shaft of the screw.

[0029] The electric rotary machine is designed in such a way that a speed-independent and large-area cooling option for components of the electric rotary machine is realized, which is easy to design.

[0030] The fluid pressure alone is sufficient to ensure the distribution of the fluid.

[0031] Furthermore, the invention provides a drive assembly for a motor vehicle, which comprises an electric rotary machine according to the invention and an output device. The output device can, in particular, be a transmission or an internal combustion engine.

[0032] The drive arrangement or the electric rotary machine itself comprises a flow generation device for generating the cooling fluid volume flow, which is fluidically coupled to the fluid supply device, wherein the flow generation device is designed such that a sufficiently large cooling fluid volume flow can be generated at the outlet, which is capable of setting the distribution element in rotation.

[0033] The rotation of the distribution element distributes the cooling fluid around the outlet of the fluid supply device.

[0034] In one embodiment of the electric rotary machine, it is provided that the electric rotary machine has a plurality of fluid supply devices and distribution elements associated therewith, in particular distributed on the stator, for the purpose of cooling windings or winding heads of the stator.

[0035] The invention described above will be explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, and it should be noted that the embodiments shown in the drawings are not limited to the dimensions shown. It is shown in Figure 1: a first embodiment of the fluid supply device with a distribution element arranged thereon, in a sectional view; Figure 2: the first embodiment of the fluid supply device with a distribution element arranged thereon, in a sectional exploded view; Figure 3: the first embodiment of the fluid supply device with a distribution element arranged thereon, in an end view; Figure 4: a second embodiment of the fluid supply device with a distribution element arranged thereon, in a sectional view; Figure 5: the second embodiment of the fluid supply device with a distribution element arranged thereon, in a sectional exploded view; Figure 6: the second embodiment of the fluid supply device with a distribution element arranged thereon, in an end view; Figure 7: individual parts of the second embodiment of the fluid supply device, in an end view; and Figure 8: individual parts of the second embodiment of the fluid supply device, in an end view.

[0036] The figures show two different variants of the fluid supply device 10 with the distribution element arranged thereon. To explain the invention, reference will first be made to the elements common to both embodiments.

[0037] The electric rotary machine comprises a fluid supply device 10 on a statically fixed element 1, here the stator. This fluid supply device 10 forms a flow channel 20 through which a cooling fluid can flow in a volume flow. In the embodiments illustrated here, the statically fixed element 1 itself forms a first section 21 of the flow channel 20. This first section 21 of the flow channel 20 comprises an internal thread 11 into which a screw 30 is screwed with a correspondingly complementary external thread 31. The screw 30 has a longitudinal bore 32 which forms a second section 33 of the flow channel 20. The longitudinal bore 32 opens into an outlet 34 through which the cooling fluid volume flow 40 can exit in an outlet direction 50.

[0038] Between the statically fixed element 1 and a screw head 35 of the screw 30, a distribution element 60 is arranged rotatably about a rotation axis 61, which in the illustrated embodiments corresponds to the longitudinal axis of the screw 30.

[0039] The hydrodynamic pressure of the cooling fluid volume flow 40 emerging from the outlet 34 in the outlet direction 50 leads to a rotation of the distribution element 60 due to a tangential flow against the distribution element 60. Due to the centrifugal force acting on the cooling fluid, cooling fluid adhering to the distribution element 60 is thrown off the distribution element 60 and distributed around the fluid supply device 10. This, and in particular when there are multiple fluid supply devices 10 on or in the electric rotary machine, ensures extensive and intensive cooling of components of the electric rotary machine.

[0040] The Figures 1 to 3The embodiment shown differs from that shown in the Figures 4 to 8 illustrated embodiment in that in the embodiment shown in Figures 1 to 3 the distribution element 60 is a disc, and in the Figures 4 to 8 illustrated embodiment is a sleeve 63.

[0041] Both the disc 62 and the sleeve 63 are designed as a substantially rotationally symmetrical part which sits on the shaft of the screw 30 with a central opening.

[0042] In the embodiment shown here, the disc 62 has an opening 64 in the form of a radial slot, which promotes the guidance of the cooling fluid radially outward during the rotational movement of the disc 62.

[0043] In the embodiment shown here, the sleeve 63 has an opening 64 in the form of a bore, which also promotes the guidance of the cooling fluid radially outwards during the rotational movement of the sleeve 63.

[0044] Furthermore, a plurality of driving elements 65 in the form of grooves are formed in the sleeve 63, distributed on the radial inner side, in order to facilitate the rotational movement of the sleeve 63 when subjected to the hydrodynamic pressure of the cooling fluid.

[0045] The respective distribution element 60 is rotatably mounted on the screw 30 with an axial play, so that the cooling fluid flowing tangentially towards the distribution element 60 can be thrown off the distribution element 60 on the side of the inflow.

[0046] With the electric rotary machine according to the invention and a drive arrangement equipped therewith, large-area cooling of the electric rotary machine can be realized in a structurally simple and cost-effective manner. List of reference symbols

[0047] 1 statically fixed element 10 fluid supply device 11 internal thread 20 flow channel 21 first section of the flow channel 30 screw 31 external thread 32 longitudinal bore 33 second section of the flow channel 34 outlet 35 screw head 40 cooling fluid volume flow 50 outlet direction 60 distribution element 61 rotation axis 62 disc 63 sleeve 64 opening 65 drive element

Claims

1. An electric rotary machine comprising a rotor that is rotatable about an axis of rotation and a stator that is arranged statically with respect to the rotor, and at least one statically fixedly arranged fluid supply device (10) and a distributor element (60) that is connected to the fluid supply device (10) in a flow-conducting manner and can be rotated relative to the fluid supply device (10), said distributor element being a component that is substantially rotationally symmetrical about its axis of rotation (61), wherein the fluid supply device (10) comprises a flow channel (20) having an outlet (34) for dispensing a cooling fluid volume flow (40) in an outlet direction (50), and an axis of rotation (61) of the distributor element (60) is arranged in relation to the outlet (34) in such a way that the outlet direction (50) is tangential to a circumference of the distributor element (60), so that the distributor element (60) can be tangentially supplied with the cooling fluid volume flow (40) emerging from the outlet (34) and the distributor element (60) can be set in rotation by the incoming flow, whereby the cooling fluid can be distributed around the axis of rotation (61) of the distributor element (60) by the distributor element (60), wherein the cooling fluid is distributed as such to at least one component of the electric rotary machine, and wherein the flow channel (20) is formed at least in sections by a longitudinal bore (32) of a screw (30) screwed into a statically fixedly arranged element (1) of the electrical rotary machine, wherein the outlet (34) is formed in the screw (30) extending from the longitudinal bore (32).

2. The electric rotary machine according to claim 1, characterized in that the outlet (34) runs substantially perpendicular to the axis of rotation of the rotor, and the axis of rotation (61) of the distributor element (60) runs parallel to the axis of rotation of the rotor.

3. The electric rotary machine according to one of the preceding claims, characterized in that the outlet (34) and the distributor element (60) are arranged and designed such that the cooling fluid volume flow (40) is directed onto a partial circumference of the distributor element (60).

4. The electric rotary machine according to any one of the preceding claims, characterized in that the distributor element (60) is a disc (62) or a sleeve (63).

5. The electric rotary machine according to any one of the preceding claims, characterized in that the distributor element (60) has at least one opening (64) leading radially outward on its circumference.

6. The electric rotary machine according to any one of the preceding claims, characterized in that the distributor element (60) has at least one driving element (65), which can be tangentially flowed against by the cooling fluid volume flow (40) and thus absorbs a tangentially acting force on the distributor element (60) due to the effect of the hydrodynamic pressure of the cooling fluid.

7. The electric rotary machine according to any one of the preceding claims, characterized in that the fluid supply device (10) i) is arranged on the stator or is formed thereby, or ii) is arranged on a housing of the electric rotary machine or is formed thereby.

8. A drive arrangement for a motor vehicle having an electric rotary machine according to any one of claims 1 to 7 and having an output device.