Rotor assembly for electric pump system

Abstract

The invention relates to a rotor assembly for an electric drive, in particular for an electric pump system, comprising a shaft which has a fastening region, a rotor part which is fastened to the fastening region in a stationary manner, and a plastic section by means of which the rotor part is fastened to the shaft, the fastening region has at least one first fastening projection and one second fastening projection which are arranged at a distance from each other by means of a fastening recess and which engage with the plastic section such that the rotor part is fixed in position on the shaft. The fastening region is provided with at least one first spiral groove and with a second spiral groove, the first spiral groove and the second spiral groove intersecting with each other in the case of providing the fastening projection. The invention further relates to a corresponding shaft, to a corresponding drive, to a corresponding pump device, and to a method for producing same.

Description

Technical Field

[0001] This invention relates to a rotor structure assembly for an electric drive device, particularly an electric pump device for a motor vehicle, a shaft for the rotor structure assembly, and methods for manufacturing the shaft and the rotor structure assembly, respectively. Furthermore, this invention relates to an electric motor including a rotor structure assembly and an electric pump device including a rotor structure assembly, respectively. Background Technology

[0002] Several different electric motors are known from the prior art as electric drive devices, which are, for example, surrounded or traversed by fluid during operation for cooling. Such a drive device is described, for example, in EP4145683 B1. Particularly for use in pumping equipment, electric motors are implemented as so-called wet rotors, with components of the wet rotor in direct contact with the fluid. Thus, for example, DE 102017203736 A1 describes an electric motor suitable, for example, for use in electric pumping equipment in motor vehicles, wherein the permanent magnet rotor portion of the electric motor is fixedly positioned on the hollow shaft by providing, for example, a motor receiving sleeve injection-molded onto the hollow shaft, the rotor portion being arranged within the motor receiving sleeve. This provides a simple rotor structure assembly for electric motors, for example, for use in pumping equipment or fluid pumps, having a drive rotor capable of rotating with the shaft, which can magnetically interact with the drive stator of the electric motor to generate torque that can be transmitted via the shaft.

[0003] The challenge in manufacturing this type of rotor assembly lies in ensuring that the corresponding plastic sections, and thus the drive rotor or rotor portion, are reliably and permanently fixed in position to the hollow shaft. In the prior art, this problem is solved by providing a fixing region on the shaft with a fixing protrusion, which is engaged by the plastic sections during the injection molding process, thereby form-locking the rotor portion to the shaft and fixing it in a fixed position. For example, KR10-2006-0133865A discloses providing a fixing region on the shaft by knurling its surface. This prevents slippage on the shaft.

[0004] However, it has been shown that the introduction of such knurling can produce undesirable damage, particularly deformation, in the case of shafts that are relatively fragile. This type of damage at least leads to dimensional inaccuracies, which, for example, hinder the concentricity of the rotor assembly. Furthermore, special tools are required to introduce such knurling, making manufacturing time-consuming. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a rotor structure assembly that at least partially improves upon at least one of the aforementioned disadvantages. In particular, the object of the present invention is to provide a simple and reliable fixation on the shaft, thereby preventing overloading of the shaft.

[0006] According to one aspect of the invention, this task is solved by a rotor structure assembly having the features of claim 1. Advantageous embodiments are described in the corresponding dependent claims.

[0007] According to a particularly simple implementation, this task has been solved by providing a rotor structure assembly whose shaft is provided with at least two helical grooves, in particular helical channels. When a fixed protrusion is provided between the spiral grooves, these spiral grooves intersect each other.

[0008] The rotor structure assembly according to the invention includes a shaft, a rotor portion fixedly fixed to a fixed region, and a plastic section. The shaft has a fixed region, and the rotor portion is fixed to the shaft via the plastic section. The fixed region has at least one first fixed protrusion and a second fixed protrusion. More specifically, the fixed region has a plurality of fixed protrusions. The fixed protrusions, i.e., at least the first and second fixed protrusions, are arranged spaced apart from each other by fixed recesses. The fixed protrusions engage with the plastic section, such that the rotor portion is fixedly fixed to the shaft, particularly in a way that prevents the rotor portion from being detached from the shaft without damage, especially without damaging at least the plastic section. In particular, the fixed protrusions are embedded in the plastic material of the plastic section. This fixed fixation at position at least limits, and in particular avoids, except for negligible clearance, the mobility and / or torsion of the plastic section relative to the shaft. According to the invention, the fixed region is provided with at least one first helical groove and a second helical groove. According to the invention, when fixed protrusions are provided, the first helical groove intersects with the second helical groove. In particular, the first helical groove is implemented in a right-handed manner, and the second helical groove is implemented in a left-handed manner. However, the invention also includes special embodiments in which these helical grooves intersect due to the suitably selected corresponding pitches. Generally, it is preferred that the first helical groove is provided by a first thread, which is particularly implemented as a right-handed thread, and / or that the second helical groove is provided by a second thread, which is particularly implemented as a left-handed thread.

[0009] Particularly preferably, the fixing region is axially spaced from at least one, and especially both, axial ends of the shaft. In particular, the fixing region is arranged eccentrically. Thus, preferably, the distance between the fixing region and one axial end of the shaft is greater than the distance to the other axial end of the shaft. In particular, the distance between the fixing region and at least one of the axial ends of the shaft is at least 25%, especially at least 30%, and especially at most 50% of the axial extension of the shaft. This allows the corresponding ends of the shaft to be designed in a manner adapted to the application, for example, to provide support surfaces for supporting the shaft. The axial extension of the shaft is an extension perpendicular to the direction in which the shaft has its minimum extension. In particular, the first fixing protrusion and the second fixing protrusion are arranged axially overlapping, wherein, in particular, the two fixing protrusions are spaced apart from each other along their peripheries by fixing recesses.

[0010] Generally, it is preferred that the fixing recess is constructed via a first and / or second helical groove. If the helical groove is provided via a first thread and a second thread, then preferably, the fixing recess is constructed via the thread path of the first and / or second thread. Therefore, preferably, the fixing protrusion is created by introducing threads when constructing the fixing recess. According to one embodiment, the first thread is implemented as a single thread path. Threads. In one embodiment, the second thread is a single-pass thread. In one embodiment, at least one of the threads is a multi-pass thread. Thread.

[0011] According to one embodiment, at least the first helical groove and / or the second helical groove has a variable pitch. According to a particularly preferred embodiment, the first helical groove and / or the second helical groove has a constant pitch. A constant pitch makes it easier to manufacture the helical grooves. Generally, it is preferred that the pitch of the first helical groove is at least 0.5 mm. According to a generally preferred embodiment, the pitch of the second helical groove is at least 0.5 mm. It has been shown that from such a pitch onwards, it is possible to create a fixing protrusion that can achieve an improved fixing position.

[0012] Preferably, the fixing recess includes a section of the base of the first helical groove and / or the second helical groove, i.e., the bottom of the groove. In particular, the fixing recess includes the thread base of the first thread and / or the second thread. Specifically, the transition from the fixing recess to the corresponding fixing protrusion is formed by a section of the groove wall of the first helical groove and / or the groove wall of the second helical groove, particularly by a corresponding thread flank of the first thread and / or the second thread. Preferably, the corresponding fixing protrusion includes a section of the thread tip of one of the threads. Particularly preferably, the first fixing protrusion includes a section of the thread tip of the first thread, and the second fixing protrusion includes a section of the thread tip of the second thread. Different thread shapes may be considered for the threads. For example, the first thread and / or the second thread may be thread shapes selected from the group consisting of flat threads, round threads, saw threads, pointed threads, trapezoidal threads, and Whitworth threads, respectively.

[0013] Generally, preferably, the rotor portion includes a plurality of permanent magnets distributed along its periphery. In an advantageous embodiment, the permanent magnets are arranged in a Halbach array. In a Halbach array, the permanent magnets are arranged in a magnetization pattern that rotates in space. In this type of embodiment, the rotor core can be omitted. However, in a preferred embodiment, the rotor portion includes a rotor core. In this embodiment, the rotor core can be implemented as a solid body. However, in a particularly preferred embodiment, the rotor core includes a plurality of stacked metal sheet segments. In particular, the metal sheet segments are assembled into a metal sheet stack (also known as a sheet stack). The metal sheet segments or metal sheet stack extends about the axis. Preferably, a plurality of the plurality of metal sheet segments have retaining sections distributed along the periphery of the rotor portion. Particularly preferably, the rotor core is implemented in a permanent magnet manner. In particular, the permanent magnets are held on the retaining sections in a manner distributed along the periphery. In particular, the permanent magnets are preferably form-locked to at least a plurality of the metal sheet segments by means of the retaining sections, respectively, relative to the radial and / or axial directions. In particular, the permanent magnet is at least partially surrounded by the plastic of the plastic segment. This enables additional positional fixation, especially without the need to glue the permanent magnet in. Generally, it is advantageous that the rotor core has end-side recesses into which the plastic segment extends. This further improves the fixation of the rotor core in or on the plastic segment. In particular, the plastic segment at least partially surrounds both the metal sheet segment and the permanent magnet.

[0014] Particularly preferably, the retaining sections are respectively constructed as recesses in the rotor core, particularly in the stack of metal sheets, into which permanent magnets are inserted. In particular, the recesses are arranged such that the permanent magnets are spaced apart from the radially outer side of the rotor core, particularly from at least 5% of the radial extension of the rotor core between its two radially opposing ends. Preferably, the recesses are open toward the axially pointing side of the rotor core, particularly the end side, particularly the corresponding same end side, which facilitates the insertion of the permanent magnets. This allows for the manufacture of metal sheet sections with simple profiles that enable particularly robust retention of the permanent magnets by the retaining sections.

[0015] According to one embodiment, the rotor portion is radially spaced from the shaft, particularly at least through a region of plastic sections, and especially spaced across the entire extension of the rotor portion. According to another embodiment, the rotor portion, particularly the rotor core, partially rests directly against the shaft.

[0016] Generally, it is advantageous to manufacture the plastic section by injection molding and overmolding the shaft and / or rotor portion. In particular, the plastic section surrounds the rotor portion at least radially and on the axial side of the rotor portion. Here, the plastic section should be understood as a monolithically manufactured, integral element, wherein the outline of the element is preferably defined at least partially by the outlines of the shaft and rotor portion. Preferably, the plastic section comprises at least one thermosetting plastic and / or one thermoplastic plastic as the plastic material. Particularly preferably, the plastic section comprises polyphenylene sulfide (PPS) as the plastic material. Such a material is particularly preferred for improved precision and robustness. According to one embodiment, the plastic section is connected to a rotor cover section, particularly in a fluid-tight manner, the rotor cover section at least partially enclosing the end side of the rotor portion. In particular, the plastic section is welded to the rotor cover section, particularly by ultrasonic welding and / or friction welding, to establish a fluid-tight connection. Preferably, the friction welding is rotary welding. Particularly preferably, the rotor cover section is arranged on the end side of the rotor portion away from the direction of the sliding bearing.

[0017] Surprisingly, the aforementioned arrangement of intersecting helical grooves ensures reliable fixation of the rotor portion to the shaft via the plastic section. This type of fixation eliminates the need for knurling or similar measures used to structure the outer surface of the shaft. Consequently, stress during the manufacture of the fixing area is reduced, particularly in terms of radial stress. This is achieved by gently peeling and / or moving the shaft material in the axial direction without deforming it, thus providing the fixing protrusion. Furthermore, it has been found that a particularly reliable engagement between the plastic section and the fixing area can be achieved by providing threads. The helical grooves create a fixing protrusion that provides a larger radial extension and (depending on the pitch of the helical groove) improved fixation relative to axial forces and / or torques. Moreover, the rotor assembly can be manufactured using simple tools. In particular, knurling tools can be omitted during manufacturing.

[0018] The rotor assembly according to the invention is particularly suitable for use in electric pump devices. Particularly preferred are liquid pumps for liquids, such as oil, water, ethylene glycol, or the like. For example, the pump device can be a lubricant pump for conveying lubricants, such as oil or the like. For example, the pump device can be a coolant pump for conveying coolants, such as water, ethylene glycol, and / or mixtures thereof.

[0019] According to an advantageous embodiment, the shaft is at least partially, and particularly over its entire axial extension, hollow. Therefore, the at least partially tubular shaft has a through-hole that provides a cavity within the shaft. The through-hole extends uninterruptedly through a fixed region, particularly the entire axial extension of the shaft.

[0020] When the shaft is constructed as a hollow shaft, it is particularly advantageous to provide a fixing protrusion using a helical groove, because compared to a solid shaft, a hollow shaft can only withstand a small radial force, thus preventing permanent deformation. Therefore, in embodiments with hollow shafts, higher shape accuracy can be ensured.

[0021] According to a preferred embodiment, the hollow shaft has a first wall thickness in the radial direction between the shaft through portion and one of the fixed protrusions, and a second wall thickness in the radial direction between the shaft through portion and the fixed recess. The second wall thickness is a maximum of 70%, particularly a maximum of 50%, and particularly a maximum of 35% of the first wall thickness. In particular, the first and second wall thicknesses are at the same axial height. Therefore, the wall thickness varies at least between the first and second wall thicknesses, particularly along the periphery of the hollow shaft. In particular, the first wall thickness is measured between the shaft through portion and the region between the first and second helical grooves, particularly between the shaft through portion and the thread tip of the first and / or second threads. In particular, the second wall thickness is measured between the shaft through portion and the base of the first and / or second helical grooves, particularly between the shaft through portion and the thread base of the first and / or second threads. In particular, the maximum groove depth of the first and / or second helical grooves is a maximum of two-thirds of the third wall thickness of the hollow shaft outside the fixed region. If the corresponding helical groove is provided by one of the threads, then in particular, the maximum groove depth is the maximum thread depth of the first thread and / or the second thread, i.e., the radial distance between the thread tip and the thread base, which is a maximum of two-thirds of the third wall thickness of the hollow shaft outside the fixed region. In particular, the shaft is configured such that, prior to the formation of the first and second helical grooves, the shaft has a constant wall thickness and / or a constant outer diameter over at least 80% of its axial extension.

[0022] By using hollow shafts with such varying wall thicknesses, material can be saved and a compact construction can be achieved. This, for example, helps to reduce the weight of the rotor assembly. Surprisingly, it has been found that by setting the wall thickness ratios as described above, sufficient dimensional stability of the shaft can be ensured. This, in turn, minimizes production errors.

[0023] According to a generally advantageous embodiment, the fixing protrusion is created by cutting. In particular, the fixing protrusion is created at least by cutting a first helical groove, especially a first thread. In particular, the fixing protrusion is created at least by cutting a second helical groove, especially a second thread. In particular, before cutting the respective helical grooves, the shaft has a constant outer diameter over at least 80% of its axial extension.

[0024] By creating the fixed protrusion through cutting, radially inward material deformation is largely avoided, ensuring that the function-related dimensions of the shaft are not altered when the fixed protrusion is introduced. This eliminates the need for further machining steps. This can be particularly advantageous in the case of thin-walled hollow shafts, where conventional methods for creating the fixed protrusion can lead to undesirable changes in the inner contour due to manufacturing processes, for example, by which the tool profile used for the creation is reflected on the inner side.

[0025] Further improvements can be achieved by suitably selecting the corresponding flank angles of the first and / or second helical grooves, especially the corresponding flank angles of the first and / or second threads. According to an advantageous embodiment, the fixing protrusion is implemented with a gradual narrowing in the radial direction. In particular, the corresponding radially oriented cross-section of the corresponding fixing protrusion decreases along the radial direction, especially by at least 20%, especially by at least 50%. Preferably, the corresponding fixing protrusion is implemented with such a gradual narrowing that an angle is formed between the first fixing wall surface of the first fixing protrusion and the second fixing wall surface of the second fixing protrusion, wherein this angle is between 25° and 85°, especially between 35° and 55°, especially at least 45°. This avoids gaps and improves the force-locking between the plastic section and the shaft for fixing the rotor portion. The second fixing wall surface points towards the first fixing wall surface. Therefore, the fixing wall surfaces point towards each other. Therefore, preferably, a corresponding thread engagement angle (Flankenwinkel) corresponding to the angle described above is generated relative to the corresponding helical groove, especially the corresponding thread.

[0026] According to a preferred embodiment, the first helical groove and / or the second helical groove extend through more than 50%, particularly at least 70%, particularly at least 85%, and particularly 100% of the axial extension of the fixing region, respectively. This maximizes the area in which the plastic segment and the shaft engage for fixing the rotor portion. In particular, at least 60%, particularly at least 85%, and particularly at least 95% of the first and second helical grooves overlap axially. By providing the largest possible overlap area, the number of fixing protrusions that the plastic segment can engage can be maximized.

[0027] Preferably, if the helical groove is provided by a thread, the fixing region includes at least two threaded channels. The at least two threaded channels are constructed by a first thread and a second thread. Therefore, preferably, the first thread has a first threaded channel within the threaded channels, wherein the second thread has a first threaded channel within the threaded channels. Preferably, the threaded channels extend from one end of the fixing region, particularly from the same end of the fixing region. Generally, preferably, the pitch of the first thread is at least 0.5 mm. According to a general embodiment, the pitch of the second thread is at least 0.5 mm. It has been found that from such a pitch, it is possible to create a fixing protrusion that enables improved, positionally fixed fixing.

[0028] According to an advantageous embodiment, the rotor assembly includes at least one sliding bearing, preferably an axial bearing. Specifically, the sliding bearing comprises an axial bearing section and a radial bearing section. The sliding bearing is fixed relative to the shaft and to the rotor portion by means of a plastic section, particularly by injection molding the sliding bearing. This eliminates the need for a separate bearing that would otherwise be fastened to the drive rotor. Particularly preferably, the sliding bearing is integrally implemented and includes a first bearing section and a second bearing section. The first bearing section has a sliding bearing surface at its end, and the second bearing section has a bearing flange and is embedded, particularly completely embedded, in the plastic of the plastic section. The sliding bearing surfaces are configured to abut against the corresponding sliding bearing surfaces of the corresponding sliding bearing sections during operation. In particular, the sliding bearing surfaces are configured for lubrication by fluid to be delivered via the rotor assembly. This reduces frictional resistance between the sliding bearing surfaces during operation. Specifically, the first bearing section extends axially across the plastic section. This ensures reliable abutment against the sliding bearing surfaces during operation. Preferably, the sliding bearing is axially positioned entirely alongside the rotor portion. Particularly preferably, the shaft extends axially across the sliding bearing. Advantageously, the sliding bearing is made of ceramic and / or graphite, which enables advantageous sliding performance.

[0029] According to a generally advantageous embodiment, the first and / or second fixing protrusions are respectively constructed in a rhomboid shape, particularly configured such that the respective fixing protrusions have a plurality of fixing wall surfaces, each forming an angle not equal to 90° with respect to a respective adjacent fixing wall surface of the same fixing protrusion. For example, the first fixing wall surface may form an angle not equal to 90° with respect to a respective adjacent fixing wall surface of the first fixing protrusion. For example, the second fixing wall surface may form an angle not equal to 90° with respect to a respective adjacent fixing wall surface of the second fixing protrusion. For example, with this type of design of the fixing protrusions (which can be achieved, in particular, by suitably cutting out the first and second helical grooves), better load distribution can be achieved while ensuring reliable fixation, because possible stresses in the circumferential direction can be deflected into axial loads.

[0030] According to another aspect, the present invention relates to a pump device, advantageously implemented as an electric pump device. Preferably, the pump device is suitable for and / or determined to be used in motor vehicles. The pump device includes a rotor structure assembly according to the invention, at least one pump rotor configured to convey fluid, particularly lubricant and / or coolant, from the inlet of the pump device to the outlet of the pump device. The rotor structure assembly is implemented as part of a drive unit, particularly an electric drive unit, for driving the pump rotor. In a preferred embodiment, the rotor structure assembly may have the features disclosed above in the context of the rotor structure assembly according to the invention. Particularly preferably, the pump rotor is fastened to the axial end of a shaft. The rotor structure assembly of the pump device constitutes the drive rotor of the drive unit. The pump rotor is fixedly connected to the shaft of the rotor structure assembly, wherein the shaft is supported between the pump rotor and the drive rotor in a manner capable of rotating about a rotation axis extending axially. This provides a hydraulic region and an electronic region, in which the pump rotor for conveying fluid is arranged, and in which the drive rotor of the drive unit is arranged, for driving the pump rotor in the hydraulic region by means of the shaft.

[0031] For example, the pump device can be implemented as an impeller pump, a cycloidal rotor pump, or the like. In an impeller pump embodiment, the pump rotor is configured as an impeller. In a cycloidal rotor pump embodiment, the pump rotor is implemented as an inner or outer rotor of a cycloidal rotor. Preferably, the corresponding pump device is implemented for a hydraulic system, for a cooling system, and / or for a lubrication system, wherein, according to another aspect, if such a system includes the pump device according to the invention, then such a system is included within the invention. For example, the pump device can be implemented as an oil pump. For example, the pump device can be implemented as a coolant pump.

[0032] According to a preferred embodiment, the pump device has a housing surrounding a pump region and a motor region. A pump rotor is arranged in the pump region for conveying fluid from an inlet to an outlet, and a drive rotor is arranged in the motor region for interacting with a drive stator of a drive unit to generate rotational motion of the pump rotor. Specifically, the pump region and the motor region are axially separated from each other by a central portion of the housing, which advantageously provides at least one radial and / or axial bearing for a shaft. Particularly preferably, the pump rotor and the drive rotor are supported by a shaft in the central portion of the housing in the form of an overhanging support structure. Specifically, the central portion of the housing includes a sliding bearing surface for axially supporting a rotor assembly, the sliding bearing surface corresponding to a sliding bearing in the rotor assembly. Specifically, the drive stator includes a plurality of stator windings, wherein the stator windings are fluid-tightly separated from the drive rotor. Specifically, the drive stator and the drive rotor are radially spaced from each other by at least an annular gap, wherein the annular gap is implemented to provide a passage for fluid from the pump chamber. Thus, the heat generated during pump operation can be effectively dissipated by the fluid for cooling the pump device. In particular, the shaft of the rotor structure assembly that provides the drive rotor of the drive device is implemented as a hollow shaft, wherein the shaft through-section provides a connection for guiding fluid between the pump region and the motor region.

[0033] According to another aspect, the present invention relates to a shaft for use with a rotor structure assembly according to the invention. The rotor structure assembly is particularly implemented for use in a pump device according to the invention, in which the rotor structure assembly can provide a drive rotor. According to this aspect of the invention, the shaft is implemented as a hollow shaft, wherein the shaft has a fixed region on which a rotor portion can be fixedly positioned by means of a plastic section, wherein the fixed region has at least one first fixing protrusion and a second fixing protrusion, the first and second fixing protrusions being configured to engage the plastic section for fixing the rotor portion to the shaft. The fixed region is provided with at least one first helical groove and a second helical groove. In the case of providing multiple fixing protrusions, the first and second helical grooves intersect each other. The first and second fixing protrusions are spaced apart, particularly by fixing recesses, wherein, preferably, the fixing recesses are provided by corresponding sections of the base of the first and / or second helical grooves, particularly the thread base of the first and / or second threads. The shaft may have the features described above in the context of the rotor structure assembly and / or the pump device.

[0034] According to another aspect, the present invention includes a rotor structure assembly for an electric drive device and a shaft for an injection-molded drive rotor for the electric drive device, the shaft being implemented as a hollow shaft. The hollow shaft may have the features described above in the context of the shaft for the rotor structure assembly and / or the pump device. Furthermore, the injection-molded drive rotor may have the features described above in the context of the shaft for the rotor structure assembly, the rotor structure assembly, and / or the pump device.

[0035] According to one aspect, the invention also relates to a method for manufacturing a shaft according to the invention. The method includes the steps of: providing a hollow shaft having a region defined as a fixed area, in which, in particular, the hollow shaft has a constant outer diameter; providing a first helical groove on the hollow shaft to create the fixed area, wherein, in particular, the first helical groove is right-handed; and providing a second helical groove on the hollow shaft such that, in the case of a fixed protrusion provided in the fixed area, the first helical groove intersects with the second helical groove, wherein, in particular, the second helical groove is left-handed. In particular, the first and / or second helical grooves are cut into the hollow shaft. The method may include other features disclosed above in the context of shafts according to the invention, rotor structures according to the invention, or pump devices according to the invention.

[0036] Furthermore, the present invention relates to a method for manufacturing a rotor structure assembly according to the invention. The method includes providing, particularly by implementing the above-described method steps for manufacturing a shaft, a shaft according to the invention. Furthermore, the method includes: providing a rotor portion and positioning and fixing the rotor portion relative to the shaft such that the rotor portion surrounds the shaft along its periphery; in the case of producing plastic sections, injection molding the rotor portion and the shaft with a plastic material, the plastic sections engaging fixing protrusions in fixing regions of the shaft, such that the rotor portion is fixedly positioned on the shaft. In particular, the rotor portion and the shaft are placed into a tool, particularly an injection molding tool, for pre-fixing the drive rotor relative to the shaft. In particular, after injection molding, the rotor structure assembly is integrally removed from the tool. The method and the components used in the method for the rotor structure assembly may each have the features disclosed above in the context of the rotor structure assembly according to the invention.

[0037] According to one aspect, the invention further relates to an electric drive device, such as an electric motor, wherein the drive device includes a drive stator comprising a plurality of stator windings, and wherein the electric drive device further has a drive rotor formed by a rotor structure assembly according to the invention, wherein the rotor portion of the rotor structure assembly is arranged axially at the height of the drive stator and is surrounded by the drive stator along its periphery. The drive rotor is supported by a shaft of the rotor structure assembly in a manner capable of rotating relative to the drive stator about a rotation axis extending axially. The drive device may have features disclosed above in the context of at least one of the rotor structure assembly according to the invention, the shaft according to the invention, the pump device according to the invention, or the method according to the invention.

[0038] According to one aspect, the invention further relates to an electric motor. This motor is configured to generate torque for transmitting rotational motion to a drive shaft. According to the invention, the motor includes an electric drive device according to the invention. According to one embodiment, the shaft of the rotor assembly is configured as a drive shaft. According to another embodiment, the shaft of the rotor assembly is coupled to the drive shaft via a transmission mechanism of the motor, particularly a planetary gear transmission mechanism.

[0039] Without limiting the generality of the foregoing, other details, advantages and features of the invention can be obtained from the following description of preferred embodiments with reference to the accompanying drawings. Attached Figure Description

[0040] The attached diagram shows:

[0041] Figure 1 This is a schematic diagram illustrating one exemplary embodiment of the rotor structure assembly.

[0042] Figure 2 A cross-sectional view shows an exemplary embodiment of the rotor structure assembly according to the present invention;

[0043] Figure 3a and Figure 3b An exemplary embodiment of the shaft according to the present invention is shown in different views;

[0044] Figure 4 Two views illustrating the structure of the fixed region of the shaft as a schematic diagram;

[0045] Figure 5 A fragment of an exemplary embodiment of a pump device according to the present invention is shown in a schematic cross-sectional view.

[0046] For ease of understanding, the same components are labeled with the same reference symbols in this invention. Detailed Implementation

[0047] Figure 1 An exemplary embodiment of the rotor structure assembly 1000 is illustrated schematically. The components of the rotor structure assembly 1000 are immobile relative to each other. The rotor structure assembly 1000 includes a shaft 1 and a member fastened to the shaft, the member including a rotor portion 2 and a plastic section 3. The rotor portion 2 is fixedly positioned to the shaft 1 by means of the plastic section 3. The shaft 1 has end sections on both sides for supporting the rotor structure assembly in a manner rotatable about a rotation axis D. The rotor structure assembly is constructed in a substantially rotationally symmetrical manner about the rotation axis D.

[0048] Figure 2 An exemplary embodiment of the rotor structure assembly 1000 according to the present invention is shown as a longitudinal section. The rotor structure assembly 1000 is suitable for use according to... Figure 5 The pump equipment. The rotor structure assembly 1000 includes a shaft 1, which is implemented as a hollow shaft and has a shaft through-hole 17 that extends uninterruptedly axially across a fixed region 11 along the entire length of the shaft. Furthermore, the shaft 1 has a fixed region 11 that extends axially through approximately 50% of the shaft. The fixed region 11 has a plurality of fixed protrusions 12, 13 between fixed recesses 14, the fixed recesses being created such that the shaft 1 has two helical grooves 15, 16 in the fixed region 11, the helical grooves being in the form of first and second threads. The first helical groove 15 intersects the second helical groove 16, thereby maintaining the absence of corresponding continuous groove walls or threaded flanks in the intersecting area, instead providing defined fixed protrusions 12, 13. Therefore, the fixed protrusions 12, 13 are spaced apart by the fixed recesses 14. In this embodiment, these threads intersect because they are cut into the shaft in opposite directions. This means that the first helical groove 15 is right-handed and therefore implemented as a right-hand thread, and the second helical groove 16 is left-handed and therefore implemented as a left-hand thread. The two helical grooves 15 and 16 extend substantially through the entire fixed area 11 and have a pitch of approximately 0.5 mm.

[0049] The rotor core of the rotor portion 2 of the rotor structure assembly 1000 is fixedly positioned on the fixed region 11. The rotor core is constructed of multiple stacked metal plate segments 21, which are not shown individually but are represented in a simplified manner as blocks, representing the stack of metal plate segments 21. Each metal plate segment 21 has a retaining section 22, which is implemented as a recess distributed along the periphery of the rotor portion 2. Permanent magnets 23 are inserted into the retaining sections 22 such that the permanent magnets 23 are held on the retaining sections 22 in a manner distributed along the periphery.

[0050] To secure the rotor portion 2 to the shaft 1, the rotor portion 2 is embedded in the plastic material of the plastic section 3 of the rotor structure assembly 1000, such that only the section on the end side remains open, which is sealed by the rotor cover section in a fluid-tight manner. The plastic section 3 is formed by injection molding the shaft 2 and the rotor portion 2. The plastic section 3 engages with the fixing protrusions 12 and 13, thereby fixing the rotor portion 2 to the shaft 1 in a fixed position. That is, form-locking is achieved relative to the axial direction along the rotation axis D and relative to the radial direction perpendicular to the rotation axis D, respectively. The injection molding of the rotor portion 2 has sufficiently ensured the fixation between the plastic section 3 and the rotor portion 2. However, it is generally advantageous that the rotor portion, especially the rotor core 2, may additionally have protrusions and / or recesses, into which the plastic material can flow during injection molding to provide additional improved form-locking.

[0051] In addition to the fixed area 11, a sliding bearing 4, implemented as an axial bearing, is provided on the shaft. The sliding bearing 4 is injection molded and encapsulated by the plastic material of the plastic section 3, and is fixed relative to the shaft 1 and relative to the rotor portion 2 by means of the plastic section 3. The sliding bearing 4 is integrally implemented, having a first bearing section and a second bearing section. The first bearing section has a sliding bearing surface on its end side, and the second bearing section forms a bearing flange and is embedded in the plastic material of the plastic section 3.

[0052] In the radial direction between shaft 1 and rotor portion 2, a plurality of recesses constructed by plastic sections 3 extend axially along the periphery throughout rotor portion 2. Generally, this helps to reduce possible internal stress in the region between shaft 1 and rotor portion 2, and also optimizes weight. Furthermore, this ensures that sufficient plastic is left between the fixing protrusions so that the plastic sections engage with the fixing protrusions for positional fixation. This is because shrinkage during injection molding is reduced compared to embodiments without recesses.

[0053] Figure 3a and Figure 3b An exemplary embodiment of the shaft 1 according to the invention is shown in oblique view, longitudinal view, and longitudinal section (which is derived from the longitudinal view as a section along the axis of rotation D), the shaft being suitable for use in the above-described combination. Figure 2 The rotor structure assembly 1000 is described. The shaft 1, implemented as a hollow shaft, has a shaft through-hole 17 having a constant inner diameter, which extends throughout the entire shaft. At the end side, the shaft 1 is beveled for easy engagement. The fixing region 11 extends centrally and offset, and a first helical groove 15 and a second helical groove 16 provide a plurality of fixing protrusions 12, 13 between the fixing recesses in the fixing region. The fixing protrusions respectively include the groove bottoms of the first and second helical grooves 15, 16. The axial distance between the fixing region 11 and one end of the shaft 1 is approximately twice the distance to the other end of the shaft 1. The shaft 1 is manufactured by providing a hollow shaft having a fixing region 11, a first helical groove 15 serving as a first thread in the fixing region, and a second helical groove 16 serving as a second thread in the fixing region, such that when the fixing protrusions 12, 13 are provided in the fixing region 11, the first helical groove 15 intersects with the second helical groove 16, wherein the first helical groove 15 and / or the second helical groove 16 are cut into the hollow shaft.

[0054] By setting fixed protrusions 12 and 13, the two wall thicknesses t1 and t2 of the hollow shaft can be determined at the same axial height, wherein the wall thickness t2 is measured at the height of the corresponding groove bottom or fixed recess 14, and the wall thickness t1 is measured at the height of the corresponding fixed protrusions 12 and 13 or the corresponding thread tip.

[0055] Figure 4 The diagram illustrates the axis, especially according to... Figure 3a and Figure 3b Two views of the structure of the fixed region of the axis. Figure 4 As can be seen on the left side, the arrangement of left-hand and right-hand threads as the first helical groove 15 and the second helical groove 16 results in the first fixing protrusion 12 and / or the second fixing protrusion 13 being constructed in a rhomboid shape, which is desirable to enable load transfer adapted to the load from the plastic segment 2 to the shaft 1. Therefore, the corresponding fixing protrusions 12, 13 have multiple fixing wall surfaces, each forming an angle α not equal to 90° with respect to the respective adjacent fixing wall surfaces of the same fixing protrusion. Furthermore, the fixing protrusions 12, 13 are implemented with a radially gradually narrowing profile according to the correspondingly selected thread type. Between adjacent fixing protrusions 12, 13, an angle α is formed between the first fixing wall surface 121 of the first fixing protrusion 12 and the second fixing wall surface 131 of the second fixing protrusion 13 pointing towards the first fixing wall surface 121 (see...). Figure 4(Right side). The fixed wall surfaces 121 and 131 extend at an angle. This angle α is between 25° and 85°. Furthermore, the hollow shaft has a specific ratio of wall thicknesses t1 and t2. For example, the second wall thickness t2 in the radial direction between the shaft through portion 17 and the fixed recess 14 can be 35% of the first wall thickness t1 in the radial direction between the shaft through portion 17 and one of the fixed protrusions 12 and 13. For example, the radial distance between the corresponding thread tip and thread bottom of the first helical groove and / or the second helical groove can be two-thirds of the third wall thickness of the hollow shaft outside the fixed area.

[0056] Figure 5 A segment of an exemplary embodiment of a pump device 2000 according to the invention is shown in a schematic cross-sectional view. The upward and leftward regions of the electric pump device 2000 are shown in a disconnected manner. The pump device 2000 is suitable for use in motor vehicles and can be used, for example, as a coolant pump having coolant as a fluid. The pump device 2000 includes components according to the combination... Figure 2 The described embodiment is a rotor structure assembly 1000. The pump device has a pump rotor 2001 for conveying fluid from the inlet to the outlet of the pump device 2000, wherein the pump rotor 2001 is an impeller or turbine. The rotor structure assembly 1000 is part of an electric drive unit for driving the pump rotor 2001. The rotor structure assembly 1000 constitutes a drive rotor 2002 of the drive unit, which is fixedly connected to the shaft 1 of the rotor structure assembly. The shaft 1 of the rotor structure assembly 1000 is supported on both sides of the rotor core 2 in a manner capable of rotating about a rotation axis D extending axially.

[0057] Furthermore, the pump unit includes a housing that encloses the pump area and the motor area. A drive rotor 2002 is arranged in the motor area, which works in conjunction with the drive stator 2003 of the drive unit to generate rotational motion of the pump rotor 2001. The pump rotor 2001 is arranged in the pump area. Accordingly, the pump area is connected to an inlet and an outlet. The pump area and the motor area are separated by a housing intermediate portion 2011, which provides a radial bearing for the shaft, the radial bearing also having an axial bearing section for working in conjunction with the sliding bearing 4 of the rotor structure assembly 1000.

[0058] The drive stator 2003 has multiple stator windings (not shown) that are fluid-tightly separated from the drive rotor 2002. This fluid-tight separation can be achieved by injection molding the drive stator 2003 and / or by providing a gap can, gap tube, or the like. The drive stator 2003 and drive rotor 2002 are radially spaced at least by an annular gap, which is configured to provide a passage for fluid from the pump chamber. This fluid can flow along a flow path that passes through the annular gap and through the shaft through-hole 17 of the shaft 1. Thus, a predetermined path for the fluid, originating from the pump region, is predefined. Furthermore, generally, fluid can enter the motor region and reach the annular gap through the bearing clearance between the radial bearing of the shaft 1 and the intermediate portion 2011 of the housing.

[0059] List of reference numerals

[0060] 1 axis

[0061] 2 Rotor section

[0062] 3 Plastic Sections

[0063] 4 sliding bearings

[0064] 11 Fixed Areas

[0065] 12 First fixed protrusion

[0066] 13 Second fixed protrusion

[0067] 14 Fixed recess

[0068] 15 First spiral groove

[0069] 16 Second spiral groove

[0070] 17. Through section of shaft

[0071] 21 Metal Sheet Section

[0072] 22. Maintain section

[0073] 23 permanent magnet

[0074] 121 First fixed wall surface

[0075] 131 Second fixed wall surface

[0076] 1000 rotor structure assembly

[0077] 2000 Pump Equipment

[0078] 2001 Pump Rotor

[0079] 2002 Drive Rotor

[0080] 2002 Drive Stator

[0081] 2010 casing

[0082] 2011 Middle part of the shell

[0083] D Rotation axis

[0084] t1 First wall thickness

[0085] t2 second wall thickness

[0086] Angle α.

Claims

1. A rotor arrangement (1000) for an electric drive, in particular for an electric pump device (2000), comprising: - a shaft (1) having a fixing region (11), - a rotor part (2) fixed in position on the fixing region (11), and - a plastics section (3) by which the rotor part (2) is fixed on the shaft (1), wherein the fixing region (11) has at least one first fixing projection (12) and a second fixing projection (13) which are arranged spaced apart from one another by a fixing recess (14) and which engage with the plastics section (3) such that the rotor part (2) is fixed in position on the shaft (1), characterized in that the fixing region (11) is provided with at least one first helical groove (15) and with a second helical groove (16), wherein the first helical groove (15) intersects the second helical groove (16) in the case of the fixing projections (12, 13) being provided, wherein in particular the first helical groove (15) is implemented right-handed and the second helical groove (16) is implemented left-handed. the shaft (1) is implemented as a hollow shaft, the shaft penetration (17) of which extends without interruption in the axial direction through the fixing region (11), in particular through the entire extension of the shaft (1).

2. The rotor structure group (1000) according to any one of claims 1 or 2, wherein the hollow shaft has a first wall thickness (tl) in the radial direction between the shaft penetration (17) and one of the fixing projections (12, 13) and, in particular at the same axial height, a second wall thickness (t2) in the radial direction between the shaft penetration (17) and the fixing recess (14), wherein the second wall thickness (t2) is at most 70%, in particular at most 50%, in particular at most 35%, of the first wall thickness (tl).

3. The rotor structure group (1000) according to claim 2, wherein the fixing projections (12, 13) are produced in a machined manner, in particular by cutting out the first helical groove (15) and / or the second helical groove (16), wherein in particular the hollow shaft has a constant wall thickness before the respective helical groove (15, 16) is cut out.

4. The rotor structure group (1000) according to any one of claims 1 to 3, wherein the fixing projections (12, 13) are implemented in a manner tapering in the radial direction, in particular such that an angle (a) is formed between a first fixing wall surface (121) of the first fixing projection (12) and a second fixing wall surface (131) of the second fixing projection (13) which points towards the first fixing wall surface (121), wherein the angle (a) is between 25° and 85°, in particular between 35° and 55°, in particular at least 45°.

5. The rotor structure group (1000) according to any of the preceding claims, wherein the first helical groove (15) and / or the second helical groove (16) respectively extends through more than 50% of the axial extension of the fixing region, 6. The rotor structure group (1000) according to any of the preceding claims, wherein ​ In particular, at least 60%, in particular at least 85%, in particular at least 95% of the first helical groove (15) and the second helical groove (16) overlap in axial direction.

7. The rotor arrangement (1000) according to any one of the preceding claims, wherein The first helical groove (15) is provided by a first thread and the second helical groove (16) is provided by a second thread, wherein the fixing region (11) comprises at least two screw channels configured by the first thread (15) and the second thread (16), and / or wherein the first thread (15) and / or the second thread (16) has a thread pitch of at least 0.5 mm, respectively.

8. The rotor structure group (1000) according to any of the preceding claims, wherein The rotor portion (2) comprises permanent magnets (23) distributed along a circumference, and / or wherein The rotor portion (2) comprises a rotor core having a plurality of metal sheet segments (21) stacked one above the other, wherein at least a plurality of the plurality of metal sheet segments (21) has a holding segment (22) distributed along a circumference of the rotor portion (2), wherein the permanent magnets (23) are held on the holding segments (22) in a manner distributed along the circumference, wherein in particular the plastic segment (3) surrounds the metal sheet segments (22) and the permanent magnets (23).

9. A pump device (2000), in particular an electric pump device, for a motor vehicle, comprising: a rotor arrangement (1000) according to any one of the preceding claims; at least one pump rotor (2001) embodied for conveying a fluid, in particular a lubricant and / or a coolant, from an inlet to an outlet; wherein the rotor arrangement (1000) is embodied as part of a drive device, in particular an electric drive device, for driving the pump rotor (2001), wherein the rotor arrangement (1000) constitutes a drive rotor (2002) of the drive device, wherein the pump rotor (41) is fixedly connected to a shaft position of the rotor arrangement, wherein the shaft (1) is supported in a manner rotatable about an axis of rotation (D) extending in axial direction between the pump rotor (2001) and the drive rotor (2002).

10. A shaft (1) for a rotor arrangement (1000) according to any one of claims 1 to 8, in particular for a pump device according to claim 9, wherein the shaft (1) is embodied as a hollow shaft, wherein the shaft (1) has a fixing region (11) on which a rotor portion (2) can be fixedly fixed by means of a plastic segment (3), wherein the fixing region (11) has at least one first fixing projection (12) and a second fixing projection (13) embodied for engaging with the plastic segment (3) for fixedly fixing the rotor portion (2) on the shaft (1), wherein the first fixing projection (12) and the second fixing projection (13) are embodied as a first screw channel and a second screw channel, respectively, The fixing region (11) is provided with at least one first helical groove (15) and with a second helical groove (16), wherein, in the case of a plurality of fixing protrusions (12, 13) being provided, the first helical groove (15) and the second helical groove (16) intersect one another.

11. A method for producing a shaft according to claim 10, wherein - a hollow shaft is provided, which has a region determined as a fixing region (11), in which region the hollow shaft has an especially constant outer diameter; - the hollow shaft is provided with a first helical groove (15) for producing the fixing region (11), wherein especially the first helical groove (15) is right-handed; - the hollow shaft is provided with a second helical groove (16) such that, in the case of fixing protrusions (12, 13) being provided in the fixing region (11), the first helical groove (15) intersects the second helical groove (16), wherein especially the second helical groove (16) is left-handed; wherein especially the first helical groove (15) and / or the second helical groove (16) is / are cut into the hollow shaft.

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