Stator

Abstract

The invention relates to a stator (1) of an electric machine (2), in particular for a drive train (3) of a motor vehicle (4), comprising a stator element (5) having an energizable winding (6) which is connected in an electrically conductive manner to a plurality of busbars (7) extending outside the stator element (5), a cable channel (8) made of an electrically non-conductive plastic material is arranged on the bus bars (7) and has at least one bus bar fixing means (9) by means of which the cable channel (8) is fixed to the bus bars (7) and the position of the bus bars (7) is fixed relative to each other.

Description

Technical Field

[0001] The invention relates to a stator for an electric machine, in particular for a drive train of a motor vehicle, comprising a stator element having an energizable winding which is electrically conductively connected to a plurality of busbars extending outside the stator element. Background Art

[0002] Electric motors are increasingly used to drive motor vehicles in order to create an alternative to fossil fuel-intensive internal combustion engines. Considerable efforts have been made to improve the suitability of electric drives for everyday use and also to be able to provide users with the driving comfort to which they are accustomed.

[0003] A detailed description of an electric drive can be found in the article by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold in the German automobile magazine ATZ, Vol. 113, May 2011, pp. 360 to 365, entitled: "Highly Integrative and Flexible-Electric Drive Unit for Electric Vehicles (Highly Integrative and Flexible-Electric Drive Unit for Electric Vehicles)", which is probably the closest prior art. The article describes a drive unit for an axle of a vehicle, which comprises an electric motor, which is arranged concentrically and coaxially with a bevel gear differential. Such a drive unit is also referred to as an electric axle or an electrically operable drive train.

[0004] Permanent magnet synchronous machines (PSM) are already used in many industrial applications and are also increasingly used in the automotive industry in the electrification process. Such permanent magnet synchronous machines usually have a stator to be energized and a permanent magnet rotor. The stator includes, among other things, stator windings, stator carriers, interconnection rings and terminals for power electronics units.

[0005] Electric machines with distributed windings or wave windings usually have an interconnection area in which the different conductors of the windings are connected to each other. This connection, also known as a bridge, is usually responsible for reversing the direction of the current flow. In addition, the interconnection can also include a so-called star point or star phase. At this point, all conductors and the currents of the different phases flow together according to the star connection. As a further component, the electric machine has a high-voltage terminal. This component is responsible for the power supply of the electric machine via the power electronics unit.

[0006] High-voltage terminals with combined interconnection regions are already known from the prior art. For example, DE 10 2019 111 825 A1 discloses a stator for an electric machine with such a high-voltage terminal. Likewise, DE 10 2018 119 831 A1 discloses an electric machine comprising a stator with concentrated windings arranged on stator teeth and at least one temperature sensor for detecting the temperature of the winding. Here, the stator component is designed as an interconnection ring, which carries, for example, one or more metal connection conductor rings.

[0007] Furthermore, a contact device is known from US 2019 / 0372422 A1, which is used to electrically connect the connection ends of a stator winding to a contact connector of a power electronics unit, wherein the corresponding conductor ends to be connected are electrically connected to each other by means of a press connection.

[0008] Such interconnection areas between the power electronics unit and the winding wire ends are usually formed with the aid of so-called busbars. These busbars are usually dimensionally stable conductor rails with the necessary profile for wiring and contacting. If such busbars are relatively long compared to their cross section due to the system design, such busbars have a relatively high sensitivity to vibrations. In this case, the busbars usually have to be reinforced to avoid damage to the component itself or to adjacent components. In order to fix or connect the busbars together, it is known that the busbars need to be overmolded for reinforcement. However, such busbars usually already have a coating, which makes it difficult or even impossible to overmold the busbars.

[0009] Although such components are known from the prior art, there is still a desire to optimize these components. Furthermore, it is an object of the present invention to provide a stator which is improved with respect to the prior art. Summary of the invention

[0010] This object is achieved by a stator of an electric machine, in particular for a drive train of a motor vehicle, comprising a stator element having a winding that can be energized and is electrically conductively connected to a plurality of busbars extending outside the stator element, wherein a cable channel formed from a non-conductive plastic material is arranged on the busbars and has at least one busbar fixing means, by means of which the cable channel is fixed to the busbars and the position of the busbars relative to one another is fixed.

[0011] According to the invention, a separately manufactured cable duct is mounted on the busbar instead of overmolding the busbar as is known from the prior art. This leads to a number of advantages, for example an easier assembly due to fewer parts to be assembled and a strap-on connection process with a preferred axial connection orientation of the cable duct relative to the stator can be achieved. Furthermore, due to the coupling of the individual fixings and the cross-sectional profile of the cable duct, a structurally rigid and strong fixing of the busbar through the cable duct can be achieved.

[0012] Furthermore, any bending tolerances that occur can be compensated, which means that the cable channel can also be used as a positioning aid during the welding process of the individual wires of the stator winding. The cable channel can also be used for transport safety during handling and logistics of the stator, so that sensitive component tolerances at the wire ends can be stabilized.

[0013] Thus, the stator according to the invention has a cable channel with an integrated busbar fixture. For example, the cable channel can accommodate a power cable of a sensor, such as a temperature sensor. This allows the cable routing of such a temperature sensor cable and the busbar fixture to be optimized in terms of robustness, installation handling and costs.

[0014] The cable duct is preferably designed as a plastic injection-molded part.

[0015] First, the individual elements of the claimed subject matter of the present invention are explained in accordance with their relevance or mentioned order in the claims, and then particularly preferred embodiments of the subject matter of the present invention are described.

[0016] The electric motor is used to convert electrical energy into mechanical energy and / or mechanical energy into electrical energy and generally comprises a fixed part called a stator or fixed armature and a part called a rotor or moving armature which is arranged movably relative to the fixed part.

[0017] In the case of an electrical machine designed as a rotating machine, a distinction is made in particular between radial flux electrical machines and axial flux electrical machines. A radial flux electrical machine is characterized in that the magnetic field lines extend in the radial direction in the air gap formed between the rotor and the stator, whereas in the case of an axial flux electrical machine the magnetic field lines extend in the axial direction in the air gap formed between the rotor and the stator. Particularly preferably, in conjunction with the invention, the electrical machine is configured as a radial flux electrical machine.

[0018] The stator of a radial flux machine usually has a cylindrical structure and usually comprises electrical laminations which are electrically insulated from one another and are constructed in a layered manner and packaged to form a laminated core. Grooves distributed over the circumference or recesses closed in the circumferential direction are embedded in the electrical laminations extending parallel to the rotor axis and accommodate the stator winding or parts of the stator winding. Depending on the configuration towards the surface, the grooves can be closed with closing elements, such as closing wedges or covers, etc., to prevent the stator winding from separating.

[0019] The stator winding is an electrically conductive conductor which has a longitudinal extension which is much greater than its diameter. The stator winding can generally have any cross-sectional shape. Rectangular cross-sectional shapes are preferred, since these allow a high packing density and thus a high power density. Particularly preferably, the stator winding is formed from copper. Preferably, the stator winding has an insulation. In order to insulate the stator winding, for example, mica paper - which for mechanical reasons can be reinforced with a glass fiber backing - can be wound in the form of a strip around one or more stator windings, which are impregnated with the aid of a curing resin. In principle, it is also possible to insulate the stator winding using a curable varnish layer without mica paper.

[0020] The stator winding can be designed as a distributed winding or as a concentrated winding.

[0021] In electric machines with concentrated windings, the interconnection of the individual windings distributed around the circumference can be achieved, for example, by means of an interconnection ring or several interconnection rings. Here, busbars, usually made of copper, can be arranged on or in a common carrier ring or separate carrier rings made of plastic, which are also known as high-voltage terminals. Sometimes, interconnection rings of this type have also been referred to as "switching rings" or "contact bridges". Interconnection rings of this type are usually placed axially on the winding package.

[0022] The rotor may comprise a high voltage terminal. The high voltage terminal may accommodate one or more busbars and in particular arrange the one or more busbars at a distance from one another in an electrically insulating manner. Typically, the high voltage terminal has a basic shape of a ring or a ring cross section, with several ring / ring cross section shaped and concentrically arranged receiving portions, such as grooves, in which the corresponding busbars are arranged. Preferably, the high voltage terminal is made of a non-conductive plastic material. In principle, it is conceivable to design the carrier ring as one piece or as multiple pieces.

[0023] The electric machine can therefore preferably have a sensor, which is in particular connected to a control device of the electric machine. The electrical conductor of the sensor can preferably be routed in a cable channel. Preferably, the sensor is designed as a temperature sensor.

[0024] In this context, a control device is to be understood as referring to a control unit for controlling the motor for the purpose of operating the motor. The control unit may particularly preferably include a power electronic module for energizing the stator or the rotor. The power electronic module is preferably a combination of various components that provide an open-loop or closed-loop control of the current to the motor, the various components preferably including peripheral components required for this purpose, such as cooling elements or power supply units. In particular, the power electronic module contains a power electronic unit or one or more power electronic unit components, which are configured to provide an open-loop or closed-loop control of the current. These power electronic unit components are particularly preferably one or more power switches, such as power transistors. The power electronic unit particularly preferably has more than two phases or current paths, particularly preferably three phases or current paths, which are separated from each other and each has at least one separate power electronic unit component. The power electronic unit is preferably designed to provide an open-loop or closed-loop control of the power per phase, wherein the peak power, preferably the continuous power is at least 10W, preferably at least 100W, particularly preferably at least 1000W.

[0025] The control device of the electric machine is used for open-loop or closed-loop control, in particular electronic open-loop or closed-loop control, of one or more technical systems of the motor vehicle. In particular, a control device can be provided for open-loop or closed-loop control of the electric machine.

[0026] The busbar may preferably have a rectangular cross section. Most preferably, the busbar is made of copper. The busbar may also have a plastic coating. Preferably, the plastic coating is made of a non-conductive plastic.

[0027] Further advantageous embodiments of the invention are described in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technically meaningful manner and can define further embodiments of the invention. In addition, the features indicated in the claims are described and explained in more detail in the description, wherein further preferred embodiments of the invention are shown.

[0028] According to an advantageous embodiment of the invention, it can be provided that the cross section of the cable duct has a substantially U-shaped profile with two parallel channel side walls and a channel base. The advantage of this design is that the U-shape allows the cable duct to be designed with a particularly high mechanical rigidity, which can also be easily achieved using injection molding or mold technology.

[0029] According to another preferred improvement of the present invention, it can also be provided that at least one cable clamping portion is arranged on at least one of the channel side walls, and the at least one cable clamping portion fixes the cable extending in the cable channel by at least partially reducing the open cross section of the cable channel to prevent the cable from leaving the cable channel. This allows improved and safer cable routing in the cable channel.

[0030] Furthermore, according to an equally advantageous embodiment of the invention, it can be provided that the busbar fixing device has at least one busbar spacing element, against which two adjacent busbars rest, and which is formed integrally with the channel base and extends out of the channel base in the direction of the busbars. The advantageous effect of this design is based on the fact that the fixing of the busbars relative to one another can be achieved together with the insertion of the cable channel in one assembly step.

[0031] According to another particularly preferred embodiment of the invention, it can be provided that the channel base rests on the busbar, whereby a defined end position of the cable channel and a particularly strong fixation of the busbar position can be achieved when the cable channel is inserted into the busbar.

[0032] Furthermore, the invention can be further developed such that a retaining element is arranged on the free end of the busbar spacing element, the retaining element at least partially engaging behind two adjacent busbars and / or at least partially engaging around two adjacent busbars, so that the cable channel is firmly held against the busbars. In an equally preferred embodiment variant of the invention, it can also be provided that the retaining element is formed integrally with the busbar spacing element, in particular integrally, which is particularly advantageous in terms of manufacturing technology and therefore also in terms of cost. In this case, it may also be advantageous to further develop the invention such that the retaining element is formed by hot caulking the busbar spacing element. The advantage that can be achieved in this way is that there is no need to provide and install a separate retaining element, which brings corresponding advantages in terms of both manufacturing and assembly.

[0033] However, according to another preferred embodiment of the subject matter of the invention, it can also be provided in principle that the busbar fixing device comprises a separate retaining element. For example, the separate retaining device can be a cable tie or a locking clip.

[0034] Finally, the invention can also advantageously be designed so that the cable channel has a Z-shaped profile in the longitudinal direction. The main advantage thereof is that the Z-shaped profile provides stress relief for the cables extending in the cable channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Without limiting the general inventive concept, the invention is explained in more detail below with reference to the accompanying drawings.

[0036] In the attached picture:

[0037] Figure 1 A motor vehicle with an electric drive train is shown in a schematic block diagram,

[0038] Figure 2 The electric machine is shown in a schematic cross-sectional view,

[0039] Figure 3 A first embodiment of a cable duct is shown in a perspective view and in a cross-sectional view in a state of being placed on a busbar,

[0040] Figure 4 A second embodiment of the cable duct is shown in a perspective view and in a cross-sectional view in a state of being placed on a busbar,

[0041] Figure 5 A third embodiment of a cable duct is shown in a perspective view and in a cross-sectional view in a state of being placed on a busbar,

[0042] Figure 6 A fourth embodiment of a cable duct is shown in a perspective view and in a cross-sectional view in a state of being placed on a busbar,

[0043] Figure 7 A fifth embodiment of a cable duct is shown in a perspective view and in a cross-sectional view in the state of being placed on a busbar. DETAILED DESCRIPTION

[0044] The invention is explained using a stator 1 for an electric machine 2 of a drive train 3 of a motor vehicle 4, as shown by Figure 1 as shown in the example.

[0045] As from Figure 2 As can be seen, the stator 1 comprises a stator element 5 having an energizable winding 6 which is electrically conductively connected to a plurality of busbars 7 extending outside the stator element 5. The busbars 7 are also connected to a power electronics unit 19 for energizing the winding 6. Furthermore, a temperature sensor 18 for monitoring the stator and / or winding temperature is arranged on or in the stator 1, wherein the temperature sensor 18 is connected to a control unit 20.

[0046] As from Figures 3 to 7 It can be seen that a cable channel 8 formed of a non-conductive plastic material is arranged on the busbar 7, the cable channel having at least one busbar fixing device 9, by which the cable channel 8 is fixed to the busbar 7 and the position of the busbars 7 relative to each other is fixed. The cross section of the cable channel 8 has a generally U-shaped profile with two parallel channel side walls 10 and a channel base 11.

[0047] The protrusion-shaped cable clamping parts 12 are arranged on the channel side walls 10, and the protrusion-shaped cable clamping parts fix the cables 13 extending in the cable channel 8 by at least partially narrowing the open cross section 14 of the cable channel 8 to prevent the cables from leaving the cable channel 8. In the example shown, the protrusion-shaped cable clamping parts 12 are alternately arranged on the channel side walls 10 in the longitudinal range of the cable channel 8.

[0048] Thus, the cable 13 of the temperature sensor 18 is guided in the cable channel 8, which is also referred to as "routing". The cable 13 is laid through the upper open cross section 14 of the U-shaped profile of the cable channel 8 and is fixed and protected in the cable channel 8 by the cable clamp 12 to prevent loss. When inserting the cable 13, a certain assembly force is required so that the cable 13 slides through the open cross section 14 and then returns to the normal position of the cable. In the embodiment shown, the cable channel 8 has a Z-shaped course in its longitudinal extension, whereby a corresponding Z-shaped cable routing is formed and stress relief of the cable 13 can be achieved.

[0049] In addition to the function of routing cables in the cable channel 8, this can also help to strengthen the busbar 7, which will be explained in more detail below. The busbar 7 is connected and fixed to the cable channel 8 at several connection points. The assembly is performed as a combination of force fit and / or form fit and can be as follows Figures 3 to 7 The different configurations are shown in FIG.

[0050] Figures 3 to 7 All of these embodiments have in common that the busbar fixing device 9 has a plurality of busbar spacing elements 16, against which two adjacent busbars 7 rest, and which are formed integrally with the channel base 11 and extend out of the channel base 11 in the direction of the busbars 7. Figures 3 to 7 As can be seen, this results in a comb-like configuration in cross section of the busbar spacing elements 16 , between which the busbars 7 then extend and rest. The channel base 11 rests on the busbars 7 .

[0051] In the embodiment shown, the cable channel 8 is fixed by means of corresponding busbar spacing elements 16 and retaining elements 15 relative to a total of six busbars 7 at three locations spaced apart in the longitudinal extension of the cable channel 8. In these retaining areas of the cable channel 8, the busbars 7 extend parallel and in the same plane, which can also be seen from Figures 3 to 7 This can be clearly seen in the cross-sectional view.

[0052] Positive locking means, for example locking means, can be provided in the outer edge region in the transverse extension of the cable channel 8, which ensures the exact positioning of the cable channel 8 relative to the busbar 7. Figure 7These locking means, which are integrally formed with the cable channel 8, can be seen particularly clearly in FIG. This means that once the cable channel is fitted, the cable channel 8 can be fixed with a positive fit relative to the busbar 7 to prevent loss.

[0053] from Figures 3 to 6 It is also clear from the figure that the busbar fixing device 9 can include a separate retaining element 15. Figure 3 In the embodiment shown, the retaining element 15 is formed as a cable tie which surrounds the cable duct 8 and the busbar 7 in cross section and thus fixes them against one another.

[0054] Figure 4 An alternative variant is shown in which the retaining element 15 is designed as a clamp. Latching lugs 21 are formed on the free legs of the U-shaped retaining element 15, which latch with the cable channel 8 in a direction transverse to the longitudinal extension of the cable channel 8 after the clamp has been pushed onto the cable channel 8 or the busbar 7. Figure 4 In the embodiment of FIG. 1 , the clip-like retaining element 15 is designed as a separate component which can be detached from the cable channel.

[0055] However, it is also conceivable that, for safety reasons against loss, the clip-like retaining element 15 is designed to be captively connected to the cable channel 8, e.g. Figure 5 The example in Figure 5 In the lower illustration designated with a of , the retaining element 15 is shown in a first assembly position in which the retaining element 15 engages with its latching lugs in corresponding locking means 22 of the cable channel 8. The retaining element can then be moved from this first assembly position into a second assembly position by sliding the retaining element 15 transversely to the longitudinal extent of the cable channel 8. Figure 5 This can be seen in the diagram marked b.

[0056] exist Figure 6 2 shows another option for designing the retaining element 15. Here, latching hooks, not further specified, are provided at the distal free ends of the busbar spacer elements 16, which together with the latching plates 23 form the retaining element 15. For this purpose, the latching plates 23 are then placed on the cable channel 8 so that the latching hooks snap into openings in the latching plates 23 provided for this purpose.

[0057] at last, Figure 7An embodiment of a cable channel 8 is shown in which a retaining element 15 is formed integrally with a busbar spacing element 16. In this case, the retaining element 15 is arranged on a free end 17 of the busbar spacing element 16, which retaining element at least partially engages behind two adjacent busbars 7 and / or at least partially engages around two adjacent busbars, so that the cable channel 8 is firmly held against the busbars 7. The retaining element 15 is formed by hot caulking the busbar spacing element 16. This can be done, for example, by pressing the busbar spacing element 16 with a counter plate after the cable channel 8 has been placed on the busbars 7.

[0058] The present invention is not limited to the embodiments shown in the accompanying drawings. Therefore, the above description should not be regarded as limiting, but rather as illustrative. The attached claims should be understood to mean that the stated features exist in at least one embodiment of the present invention. This does not exclude the existence of other features. Where the claims and the above description define a "first" feature and a "second" feature, such naming is used to distinguish between two features of the same type without defining the order of precedence.

[0059] Reference numerals list

[0060] 1 Stator

[0061] 2 Motor

[0062] 3 Drivetrain

[0063] 4 Motor vehicles

[0064] 5 Stator components

[0065] 6 Winding

[0066] 7 Busbar

[0067] 8 Cable channels

[0068] 9 Busbar fixing device

[0069] 10 Channel side wall

[0070] 11 Channel base

[0071] 12 Cable clamp

[0072] 13 Cables

[0073] 14 Open cross section

[0074] 15. Retaining element

[0075] 16 Busbar spacing element

[0076] 17 end

[0077] 18 Temperature sensor

[0078] 19 Power Electronics Unit

[0079] 20 Control unit

[0080] 21 Latch tab

[0081] 22 Locking device

[0082] 23 Latch plate

Claims

1. A stator (1) of an electric machine (2), in particular for a drive train (3) of a motor vehicle (4), comprising a stator element (5) having a winding (6) which can be energized and is electrically conductively connected to a plurality of busbars (7) extending outside the stator element (5), It is characterized in that A cable duct (8) made of non-conductive plastic material is arranged on the busbar (7) and has at least one busbar fixing device (9) by means of which the cable duct (8) is fixed to the busbar (7) and the position of the busbars (7) relative to each other is fixed.

2. The stator (1) according to claim 1, It is characterized in that The cross section of the cable channel (8) has a substantially U-shaped profile having two parallel channel side walls (10) and a channel base (11).

3. The stator (1) according to claim 1 or 2, It is characterized in that At least one cable clamping portion (12) is arranged on at least one of the channel side walls (10), and the cable clamping portion fixes a cable (13) extending in the cable channel (8) to prevent the cable (13) from leaving the cable channel (8) by at least partially reducing an open cross section (14) of the cable channel (8).

4. The stator (1) according to any one of the preceding claims, It is characterized in that The busbar fixing device (9) has at least one busbar spacing element (16), against which two adjacent busbars (7) rest, and which is formed integrally with the channel base (11) and extends out of the channel base (11) in the direction of the busbars (7).

5. The stator (1) according to any one of the preceding claims 2 to 4, It is characterized in that The channel base (11) rests on the busbar (7).

6. Stator (1) according to any one of the preceding claims 4 to 5, It is characterized in that A retaining element (15) is arranged on the free end (17) of the busbar spacing element (16), which retaining element at least partially engages behind two adjacent busbars (7) and / or at least partially engages around the two adjacent busbars, so that the cable channel (8) is firmly held against the busbars (7).

7. The stator (1) according to claim 6, It is characterized in that The retaining element (15) is formed integrally, in particular monolithically, with the busbar spacer element (16).

8. The stator (1) according to claim 7, It is characterized in that The retaining element (15) is formed by heat caulking the busbar spacer element (16).

9. The stator (1) according to any one of claims 6 to 8, It is characterized in that The busbar fixing device (9) comprises a separate retaining element (15).

10. Stator (1) according to any one of the preceding claims, It is characterized in that The cable channel (8) has a Z-shaped course in its longitudinal extension.

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