Stator lamination stack assembly for a stator of an electric drive machine

Abstract

The invention relates to a stator lamination stack assembly for a stator of an electric drive machine of a motor vehicle, comprising a stator lamination stack having a plurality of stator laminations which form a stator outer jacket that has a plurality of recesses spaced apart from one another, wherein a circumferential sealing means is arranged in at least two of the recesses.

Description

[0001] 23-3162 DE

[0002] - 1 -

[0003] Stator lamination stack arrangement for a stator of an electric drive machine

[0004] The invention relates to a stator lamination stack arrangement for a stator of an electric drive motor of a motor vehicle and a method for its assembly. In particular, a cooling arrangement for the stator is provided.

[0005] Various methods for cooling stators of electrical machines are known from the prior art: for example, shell cooling of stators in which cooling channels are incorporated into the housing; or shell cooling in which a stator sleeve with cooling channel walls is provided, which are formed on the sleeve, with the cooling channels resulting from the inner shell of the housing.

[0006] However, the established solutions with cooling channels in the housing or with stator sleeves have several disadvantages. Firstly, the manufacturing of the housing or stator sleeve is complex and expensive. Secondly, the minimum wall thicknesses required for mechanical strength and sealing necessitate additional installation space and increase weight. Furthermore, the wall thicknesses and air gaps at component boundaries create thermal contact resistances that impair the cooling effect.

[0007] Based on this prior art, the invention is based on the objective of providing an improved cooling arrangement for the stator of an electrical 23-3162 DE

[0008] - 2 -

[0009] To provide a drive unit that enables efficient cooling while avoiding or at least reducing the aforementioned disadvantages of the state of the art. In particular, a cost-effective and space-optimized solution should be created in which thermal contact resistances are minimized.

[0010] Each of the independent claims, with its features, defines an object that solves this problem. The dependent claims relate to advantageous embodiments of the invention.

[0011] According to one aspect, a stator lamination stack arrangement is proposed for the stator of an electric drive motor of a motor vehicle. The stator lamination stack arrangement comprises a stator lamination stack with a plurality of stator laminations forming an outer stator shell with several spaced-apart recesses. A cooling jacket with a liquid coolant is not implemented—as in known solutions—by means of an additional or cast-on component (e.g., stator support), but directly via the recesses in the outer shell of the stator lamination stack.

[0012] In at least two of the recesses, a circumferentially circulating sealant is arranged, in particular, contained. Each sealant is designed, according to different embodiments, with an O-ring and / or a sealing ring with a different cross-section (for example, rectangular, square, oval, or freely shaped). The sealant is, in particular, formed in one piece and / or made of a plastic or another material suitable due to its macroelasticity.

[0013] This design ensures a reliable seal between the cooling channels and the machine interior, eliminating the need for separate, additional seals between the stator and housing. The seals can be cost-effectively pre-installed directly into the recesses.

[0014] According to one embodiment, at least the recesses arranged longitudinally between those recesses in which a sealing agent is provided are designed to receive a coolant. In this way, the 23-3162 DE

[0015] - 3 -

[0016] Recesses between the sealed recesses can be used as cooling channels for a coolant if, according to one embodiment, they form a suitable cooling channel geometry, in particular with a combination of circumferential and axial channels. The sealing with the circumferential sealant creates a reliable cooling circuit in the stator, whereby the coolant can be routed directly past the stator lamination stack without additional components.

[0017] According to another embodiment, the spaced-apart recesses are shaped such that, with respect to the axial extent of the stator, one or more stator laminations with a maximum diameter equal to that of the stator shell and one or more stator laminations with a recess diameter equal to that of the stator shell are arranged alternately. This alternating arrangement of stator laminations with different diameters allows the recesses to be formed easily without requiring subsequent machining of the stator lamination stack. The recesses can be integrated during the manufacturing of the stator lamination stack itself.

[0018] According to one aspect, an electric drive motor for a motor vehicle comprises a stator with a stator lamination stack arrangement according to an embodiment of the invention, as well as a motor housing with a housing cover and a housing shell, which includes an inner housing shell. The stator lamination stack arrangement rests against the inner housing shell at least radially by means of sealing elements. In this way, the stator lamination stack arrangement with the integrated sealing elements can be positioned directly against the inner housing shell, thereby achieving a reliable seal to the housing without the need for additional seals between the stator and the housing.

[0019] According to one embodiment, the stator lamination stack assembly is supported at least radially by means of the sealing means against the inner housing shell, particularly for force transmission, wherein a circumferential channel with a radial width is formed between the outer stator shell and the inner housing shell. The radial support of the stator lamination stack assembly by means of the sealing means against the inner housing shell ensures stable mounting. The circumferential channel between the outer stator shell and 23-3162 DE

[0020] - 4 -

[0021] The inner casing can serve as a cooling channel for a coolant, with the radial width of the circumferential channel being adjustable to meet cooling requirements.

[0022] According to another embodiment, the stator lamination stack is supported at least radially by means of the stator laminations with the maximum diameter of the stator shell against the inner housing shell, particularly for force transmission. The stator laminations with the maximum diameter are thus supported directly against the inner housing shell, enabling stable mounting without the need for additional support elements. The force is transmitted into the housing directly via the stator laminations.

[0023] According to one embodiment, the electric drive machine is characterized by a housing base seal for sealing the recesses on the stator outer shell against the housing base and / or a housing cover seal for sealing the recesses on the stator outer shell against the housing cover. This housing base seal and / or housing cover seal, in conjunction with the circumferential sealing elements in the recesses, achieves a reliable axial and radial seal of the cooling channels, thus ensuring a completely sealed cooling circuit. The seals can be easily positioned between the stator and the housing.

[0024] According to one embodiment, the method for assembling a stator of an electric motor vehicle comprises the steps of creating recesses in the outer contour of at least a portion of the stator laminations, arranging a plurality of stator laminations relative to one another to form a stator lamination stack, and applying a sealing agent to each of the two outermost longitudinal recesses of the stator lamination stack. This method allows the circumferential sealing agents to be integrated during the manufacturing of the stator lamination stack. By placing them in the outermost axial recesses, a complete seal of the cooling circuit is achieved without the need for subsequent sealing steps.

[0025] According to a further embodiment, the method is characterized in that the stator lamination stack assembly is inserted into a housing pot of the machine housing until it reaches a stop, and then a housing cover is placed on the housing pot and fixed in place. In this way, the stator lamination stack assembly 23-3162 DE

[0026] - 5 - with integrated sealants, they can be easily inserted into the housing. Furthermore, fitting the housing cover provides an axial seal for the cooling channels, making the installation of the stator in the housing extremely simple and requiring no additional steps.

[0027] According to one embodiment, a jacket sealing layer is designed to seal an environment watertight against a water-based and / or oil-based coolant.

[0028] This also makes it possible to achieve liquid cooling directly in the stator for dry-running drive machines, where, moreover, due to the arrangement of the cooling channels (i.e., correspondingly stacked recesses of the individual stator laminations), a simple coolant supply from the housing shell is possible.

[0029] According to a further aspect, an electric drive machine for a motor vehicle is disclosed, comprising a stator with a stator lamination stack according to an embodiment of the invention, as well as a machine housing with a housing cover and a housing pot, which has an inner housing shell on which the outer shell of the stator is arranged, in particular pressed in.

[0030] The electric drive machine, in particular the machine housing, has a housing base seal for sealing the recesses on the stator outer shell against the housing base, and a housing cover seal for sealing the recesses on the stator outer shell against the housing cover.

[0031] This also makes it possible to achieve liquid cooling directly in the stator for dry-running drive machines, where, moreover, due to the arrangement of the cooling channels (i.e., correspondingly stacked recesses of the individual stator laminations), a simple coolant supply from the housing shell is possible.

[0032] The invention is based, among other things, on the idea of ​​forming the jacket cooling via a coated stator directly in the housing, wherein the cooling channels of the cooling jacket are formed between the outer contour of the stator outer jacket and an inner contour of a housing inner jacket, so that the recesses of the adjacent 23-3162 DE

[0033] - 6 - the stator laminations arranged in the stator lamination stack form the coolant channel cross-sections. Furthermore, the invention is based on the idea of ​​using the recesses – in particular the two longitudinally outermost recesses – for the axial sealing of the cooling channels formed between the housing and the stator lamination stack.

[0034] The stator lamination stack can be produced, for example, using a progressive die (a process known in itself). The outer geometry of the stator, i.e., the stator outer shell, which later guides the coolant flow in the cooling jacket, is then shaped using the progressive die tool to achieve an efficient cooling geometry. For example, recesses (e.g., U-shaped, V-shaped, or at right angles) are cut into the outer circumference of each individual stator lamination at the same circumferential positions, so that the assembled stator lamination stack has axially extending cooling channels. Alternatively, different laminations with (especially two) different outer diameters can be processed, so that the recesses are formed by the arrangement of radially larger and smaller laminations, and the assembled stator lamination stack has circumferentially extending cooling channels.

[0035] The stator lamination stack is built up sheet by sheet, creating a 3D geometry on the stator's outer diameter due to the cutouts. This geometry increases the surface area and thus the cooling efficiency. Depending on the coating used, this stator is then bonded, stamped, or laser-welded, for example, using a baking process. After completion, the stator is masked, so that in the subsequent process, only the outer geometry and the top sheet need to be coated to achieve sufficient coolant sealing. This coating can be applied using various methods, either powder coating or paint. The coating must be coolant-tight and have sufficient thermal conductivity.

[0036] A sealing element, for example an O-ring, is then inserted into each of the two outermost longitudinal recesses, particularly one that circumferentially. This is achieved, in particular, by means of an elastically expanded application, whereby the nominal inner diameter of the sealant is selected such that it is drawn into the recess and forms a fluid-tight seal against the recess base, while the 23-3162 DE

[0037] - 7 -

[0038] The nominal outer diameter extends radially beyond the maximum diameter of the stator shell to ensure a fluid-tight seal against the housing.

[0039] The stator – that is, the wound stator lamination stack – is then inserted into the machine housing of the drive motor so that the two sealing elements form a fluid-tight seal against the housing, thus defining the designated cooling channels. The stator is bolted and clamped to the B-bearing shield (i.e., the housing cover). In one embodiment, the stator also features a locking mechanism on both the A- and B-bearing sides for torque support. The result of the invention is a simple and cost-effective jacket cooling system with highly efficient cooling, as there is no additional heat transfer between the medium and the stator.

[0040] According to one embodiment, the casing sealing layer has a circumferential sealing layer in the recesses, particularly on the groove walls and groove base, and / or in the non-recessed areas, particularly on the entire outer stator casing (including groove walls and groove base), extending circumferentially and axially to the stator. This type of seal can be easily applied, for example, by painting the already assembled stator lamination stack.

[0041] According to one embodiment, the sealing layer between adjacent pairs of stator laminations has a radial sealing layer that extends both radially and circumferentially around the stator. This type of seal allows for a very reliable sealing process because the stator laminations, which are already pre-treated with a baking varnish, only need to be heated in a controlled manner after being stacked to form the stator lamination stack, in order to create a fail-safe seal.

[0042] According to one embodiment, the radial sealing layer is formed by means of a baking varnish, applied in particular before the machining of the stator geometry, which is designed to form a sealing layer between adjacent laminations when the stator lamination stack is heated, in particular to a predetermined baking temperature. 23-3162 DE

[0043] - 8 -

[0044] According to one embodiment, the spaced-apart recesses are formed by alternately arranging one or more stator laminations with a maximum diameter of the stator shell and one or more stator laminations with a recess diameter of the stator shell along an axial extension of the stator, so that axially spaced recesses, particularly circumferential cooling channel grooves, are formed on the stator outer shell. This allows for the simplest possible formation of a shell cooling system with multiple cooling channels, each extending circumferentially and axially spaced from one another, for example, by means of stator laminations with a shell diameter that may have one or more recesses at specific points to connect adjacent cooling channels.

[0045] According to one embodiment, the outer shell sealing layer is applied to the stator shell after the stator laminations have been arranged, using a circumferential sealing layer.

[0046] According to one embodiment, the shell sealing layer is applied to the surface sides of the stator laminations with a radial sealing layer before the stator laminations are arranged.

[0047] Stator laminations are, in particular, thin sheets of electrical steel that are stacked on top of each other insulated to form the stator of an electrical machine.

[0048] In this context, a stator is understood to be, in particular, the stationary part of an electrical machine that contains the stator windings.

[0049] In this context, an electric drive machine is understood to be, in particular, a machine that converts electrical energy into mechanical rotational energy and serves as a drive, for example for a motor vehicle.

[0050] In this context, a motor vehicle is understood to mean in particular a vehicle that is driven by a power source, such as an electric motor.

[0051] In this context, the term "stator outer shell" refers in particular to the outer cylindrical casing of the stator lamination stack, which forms the outer circumference of the stator. 23-3162 DE

[0052] - 9 -

[0053] Recesses are understood to be, in particular, cutouts or depressions in the surface of the stator outer shell, which can serve as cooling channels, for example in the form of circumferential and / or axially extending grooves on the stator shell.

[0054] In this context, a sealant is understood to be, in particular, a component used to seal the stator lamination stack and the stator housing against each other in order to prevent coolant from escaping from a designated cooling channel. A sealant is, in particular, formed with an O-ring and / or a sealing ring with a different cross-section (for example, rectangular, square, oval, or freely shaped). The sealant is, in particular, formed in one piece and / or made of a plastic or another material suitable due to its macroelasticity.

[0055] In this context, the circumferential direction refers in particular to the direction along the circumference of the cylindrical outer shell of the stator.

[0056] In this context, axial extension refers in particular to the longitudinal extension in the direction of the rotation axis of the stator.

[0057] In this context, a coolant is understood to be, in particular, a liquid, for example oil-based or water-based, which is used to cool the stator lamination stack and / or the housing by absorbing and dissipating heat.

[0058] In this context, a machine housing is understood to mean, in particular, a housing in which the electric drive motor is located. A housing cover is understood to mean, in particular, a removable cover of the machine housing. A housing pot is understood to mean, in particular, the fixed lower part of the machine housing. A housing inner shell is understood to mean, in particular, the inner wall of the housing pot, especially where the stator is mounted in the housing. 23-3162 DE

[0059] - 10 -

[0060] In this context, a circumferential channel is understood to be, in particular, an annular channel between the outer stator shell and the inner housing shell.

[0061] In this context, radial width refers in particular to the distance in the radial direction between two concentric surfaces, in particular the outer stator shell and the inner housing shell.

[0062] In this context, a maximum diameter refers in particular to the largest diameter of the stator laminations.

[0063] In this context, a recess diameter refers in particular to a reduced diameter of the stator laminations with recesses.

[0064] In this context, an outer contour refers in particular to the outer outline or shape of the stator laminations.

[0065] In this context, a stop is understood to be, in particular, a component against which another component abuts and thus reaches a defined end position.

[0066] In this context, "fixing" refers in particular to the fastening or locking of components in a specific position and / or orientation.

[0067] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the figures:

[0068] Fig. 1 schematically shows an electric machine with a stator lamination stack arrangement according to an exemplary embodiment of the invention after the stator has been mounted in a stator housing.

[0069] Fig. 2 schematically shows the electric machine with the stator lamination stack arrangement from Figure 1 before the stator is mounted in the stator housing. 23-3162 DE

[0070] - 11 -

[0071] Fig. 3 schematically shows an electric machine with a stator lamination stack arrangement according to a further exemplary embodiment of the invention after the stator has been mounted in a stator housing.

[0072] Figures 1 and 2 schematically show an electric machine 1 with a stator lamination stack 2 with a plurality of stator laminations 3 and two sealing means 24 and 26 according to an exemplary embodiment of a stator lamination stack arrangement.

[0073] Fig. 1 shows the electric machine 1 fully assembled, Fig. 2 shows it before the stator is inserted into the housing 6 and before the housing cover 8 is fitted. The thick, sketched arrows in Fig. 2 roughly indicate the directions of the assembly movements.

[0074] This embodiment relates to a cost-effective and highly efficient jacket cooling system for an electric jacket cooling system. The focus is on an electric drive unit for electrically powered motor vehicles, such as electric or hybrid vehicles. Such electric drive units typically comprise an electric machine 1 with a stator 2 and a rotor (not shown) rotatably mounted relative to the stator, which in turn is non-rotatably connected to a rotor shaft (not shown) of the electric machine 1. The rotor shaft can be coupled to a transmission of the motor vehicle for torque transmission and, in this embodiment, is guided through the recess 10 in the housing 6.

[0075] The electric machine 1 can be arranged in the machine housing 4 together with the gearbox (not shown) and power electronics (not shown). This machine 1 typically requires cooling due to the continuous power output required. In this embodiment, this is achieved by means of a cooling jacket 12, which has a coolant inlet 14, several cooling channels 16, and a coolant outlet 18 in the housing 6.

[0076] In the exemplary embodiment, the cooling jacket 12 is formed directly with the machine housing 4 by means of the stator lamination stack 2, without a separate jacket component. 23-3162 DE

[0077] - 12 -

[0078] For this purpose, the stator lamination stack 2 is manufactured using a progressive die stamping machine, through which the outer geometry of the stator lamination stack 2 with recesses 15 is introduced.

[0079] The recesses 15 form the cross-sections for the cooling channels 16, which guide the water through the cooling jacket 12 and are designed to provide an efficient cooling geometry. In this embodiment, the cooling channels 16 shown are circumferential. Axial connecting channels, which may also be recessed into the outer jacket of the stator lamination stack, are not shown.

[0080] In both embodiments shown in Figures 1 and 2, the recesses 15 are formed by alternately arranging several stator laminations 3a with a maximum diameter of the stator shell and several stator laminations 3b with a recess diameter of the stator shell along an axial extent of the stator, so that axially spaced recesses 15 are formed as circumferential cooling channels 16 on the outer stator shell 13. This cooling shell geometry is created by stacking the stator lamination stack 2 laminations one on top of the other, alternating between several laminations 3a and several laminations 3b.

[0081] The stacked stator laminations 3a, 3b are coated on their sides with a baking varnish 20 (symbolically represented by wavy lines) and are firmly joined after stacking by means of a baking process in which the baking varnish develops an adhesive effect due to the high temperature.

[0082] The stator lamination stack 2 is thus constructed from the individual laminations 3a and 3b. The stator lamination stack 2 is then masked with a shell sealing layer 22, whereby only the outer geometry (i.e., the outer shell of the stator lamination stack) is coated. This masking can be applied, for example, by powder or paint using various methods, including methods known per se. The shell sealing layer 22 must be coolant-tight and thermally conductive in order to keep the coolant from the machine interior 9 beyond the cooling channels 16 away, 23-3162 DE

[0083] - 13 - but on the other hand to enable good heat transfer from the stator laminations to the coolant in the cooling channels 16.

[0084] The windings (not shown) are then inserted into the stator lamination stack 2, and the stator formed in this way is pressed into the machine housing 4, so that a firm connection is formed between the inner housing shell 7 and the outer stator shell 13 (at the laminations 3a with the maximum diameter of the stator shell) and the cooling channels 16 are also separated from the machine housing 4.

[0085] The coolant flow is axially delimited or sealed by means of a first sealing element 24 designed as an O-ring, which is arranged in the recess 15 located longitudinally closest to the A-bearing side 100, and by means of a second sealing element 24 designed as an O-ring, which is arranged in the recess 15 located longitudinally closest to the B-bearing side 200.

[0086] As can be seen from Figure 2, the stator is inserted into the housing pot 6 so that the sealing agents 24 and 26 are in contact with the inner shell of the housing pot 6 and form a coolant-tight, completely circumferential connection.

[0087] The stator is then screwed to the B-bearing shield and clamped, see Fig. 2.

[0088] Additionally, the stator can have a locking mechanism for torque support on the A and B bearing sides.

[0089] The shell sealing layer can be designed in the described or other embodiments such that the shell sealing layer 22 is a masking applied over the outer shell as a circumferential sealing layer or a layer of baked-on enamel arranged between the stator laminations, which acts as the (especially radial) seal of the machine interior 9 against coolant (especially together with the axial seals 24 and 26). 23-3162 DE

[0090] - 14 -

[0091] Figure 3 shows an electric machine 1 according to a further embodiment. The electric machine of Figure 3 differs from that of Figure 1, in particular in that the cooling channel is also formed radially outside the recesses 15. In other words, the coolant can cross over in the axial direction between the individual recesses 15, so that the recesses 15 are designed, in particular, to break up a laminar flow of the coolant and thus to improve heat dissipation from the stator lamination stack 2.

[0092] In addition to the function of axially limiting the cooling channels, the sealing agents 24 and 26 can also perform the function of radially centering the stator in this embodiment.

[0093] In this case, the sealing elements 24 and 26 must each be sufficiently rigid to bear the required load. For example, a design as a two-component component with a rigid structural component (e.g., made of a rigid plastic or a metal material) and an inner and an outer circumferential sealing lip is possible.

[0094] Of course, another, conventional radial centering configuration is also possible. In that case, the sealing elements 24 and 26 can be designed as standard O-rings, as in the embodiment shown in Figure 1.

[0095] 23-3162 DE

[0096] - 15 -

[0097] REFERENCE MARK LIST

[0098] 1 electric machine

[0099] 2 Stator lamination package

[0100] 3 Stator laminations

[0101] 3a Stator lamination with maximum diameter

[0102] 3b Stator lamination with recess diameter

[0103] 4 machine housings

[0104] 6 Housing pot

[0105] 7 Inner casing

[0106] 8 Case covers

[0107] 9 Engine room

[0108] 10 recesses

[0109] 12 Cooling jacket

[0110] 13 Stator outer casing

[0111] 14 Coolant inlet

[0112] 15 exceptions

[0113] 16 cooling channels

[0114] 18 Coolant outlet

[0115] 20 Baking varnish

[0116] 22. Jacket sealing layer

[0117] 24 Housing base seal

[0118] 26 Housing cover gasket

[0119] 28 Circumferential channel

[0120] 100 A-storage side

[0121] 200 B-storage side

[0122] A Axial extension

[0123] B radial width

Claims

1. 23-3162 DE - 16 - REQUIREMENTS 1. Stator lamination stack arrangement (2) for a stator of an electric drive machine (1) of a motor vehicle, having - a stator lamination stack with a plurality of stator laminations forming a stator outer shell (13) which has several spaced-apart recesses (15), characterized in that a circumferential sealing means is arranged in at least two of the recesses.

2. Stator lamination stack arrangement according to claim 1, characterized in that at least the recesses which are arranged longitudinally axially between those recesses in which a sealing means is arranged are designed to receive a coolant.

3. Stator lamination stack arrangement according to one of the preceding claims, characterized in that the spaced-apart recesses are formed by alternately arranging one or more stator laminations (3a) with a maximum diameter of the stator shell and one or more stator laminations (3b) with a recess diameter of the stator shell with respect to an axial extent (A) of the stator.

4. Electric drive machine (1) for a motor vehicle, comprising a stator with a stator lamination stack arrangement (2) according to one of the preceding claims and a machine housing (4) with a housing cover (8) and a housing pot (6) which has an inner housing shell (7) against which the stator lamination stack arrangement radially abuts by means of the sealing means.

5. Electric drive machine (1) according to claim 4, characterized in that the stator lamination stack arrangement is radially supported on the inner housing shell (7) by means of the sealing means, wherein a circumferential channel (28) [for receiving a coolant] with a radial width (B) is formed between the outer stator shell (13) and the inner housing shell (7). 23-3162 DE - 17 - 6. Electric drive machine (1) according to claim 4, characterized in that the stator lamination stack arrangement is radially supported on the inner casing (7) by means of the stator laminations (3a) with the maximum diameter of the stator shell.

7. Electric drive machine (1) according to claim 6, characterized by a housing base seal (24) for sealing the recesses on the stator outer shell against the housing base, and / or a housing cover seal (26) for sealing the recesses on the stator outer shell against the housing cover.

8. Method for assembling a stator lamination stack arrangement of an electric machine of a motor vehicle, comprising: - Including recesses (15) in an outer contour (13) of at least a part of the stator laminations (3b), - Arranging a plurality of stator laminations (3a, 3b) relative to each other to form a stator lamination stack (2), - Apply a sealant to each of the two outermost longitudinal recesses of the stator lamination stack.

9. Method according to claim 8, characterized by the steps: - Inserting the stator lamination stack assembly into a housing pot (6) of the machine housing until it reaches a stop, - Placing and securing a housing cover (8) onto the housing pot.

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