Drive unit of a motor vehicle

Abstract

The invention relates to a drive unit (10) of a motor vehicle (2), in particular of a steering system, said drive unit comprising: a carrier unit (16); and an electric motor (22) which has a stator assembly (20) and an additional assembly (41) that has an end shield (42). The stator assembly (20) is inserted into a receptacle (18) of the carrier unit (16), the end shield (42) being secured to the carrier unit (16) in such a manner that the stator assembly (20) is enclosed by means of the end shield (42). The invention also relates to a method (42) for creating a drive unit (10).

Description

[0001] Description

[0002] Drive unit of a motor vehicle

[0003] The invention relates to a drive unit of a motor vehicle, comprising a carrier unit and an electric motor. Furthermore, the invention relates to a method for producing a drive unit. The drive unit is, in particular, a component of a steering system.

[0004] Motor vehicles, such as passenger cars, typically have a steering system that allows the direction of travel to be adjusted. The steering system typically comprises a steering wheel located inside the vehicle and connected to a steering column. Attached to the steering column is a gearwheel that meshes with a rack, which in turn is mounted on the pivoting front wheels of the vehicle. Thus, when the steering wheel rotates, the rack is moved transversely, changing the steering angle of the wheels.

[0005] To increase comfort, a steering motor, designed as an electric motor, is usually also present. This assists the driver's steering movement, thus reducing the force required by the driver to operate the steering wheel while still allowing the wheels to be adjusted appropriately. To reduce weight and increase safety in the event of an accident, steering systems are known in which there is no mechanical coupling between the steering wheel and the front wheels. A sensor detects the angular position of the steering wheel or other control element, and the steering motor, which drives the steering rack, is controlled based on this position. Such a system is also referred to as a "steer-by-wire" system.The steering motor is typically attached to a support unit of the motor vehicle, which is held on the body and on which, for example, the steering rack or other components of the steering system are mounted. The support unit is provided, for example, by the body or at least manufactured by a motor vehicle manufacturer, whereas the steering motor is provided, for example, by a supplier. Since the steering motor is intended to enable a relatively precise adjustment of the motor vehicle's direction of travel, it is necessary that the connection points of the steering motor to the support unit, as well as the support unit and the steering motor, have only small manufacturing tolerances, which leads to increased manufacturing costs.

[0006] The steering motor is also usually provided by the supplier as a separate unit that is fully encapsulated to prevent the ingress of foreign particles during operation, which could otherwise damage the electric motor. Due to its design as a unit, it is comparatively large, which makes assembly more difficult. The steering motor also usually has a housing that is cup-shaped or hollow cylindrical with an opening closed by a bearing shield. The individual components of the steering motor are inserted through this opening during production. To ensure the required tightness, the bearing shield is usually welded all the way to the housing or connected to it using an interference fit.However, it is possible that dirt particles may build up inside the housing, which could impair the functionality of the steering motor.

[0007] The invention is based on the object of providing a particularly suitable drive unit for a motor vehicle and a particularly suitable method for producing a drive unit, wherein operational reliability is advantageously increased and manufacturing costs and / or manufacturing time are reduced. With regard to the drive unit, this object is achieved according to the invention by the features of claim 1 and with regard to the method by the features of claim 10. Advantageous further developments and refinements are the subject of the respective subclaims.

[0008] The drive unit is a component of a motor vehicle. In other words, the drive unit is suitable, in particular intended and configured, to form a component of the motor vehicle in the assembled state. The motor vehicle is in particular land-based and preferably designed with multiple tracks. In this case, it is suitably possible to position the motor vehicle essentially freely, in particular on a corresponding roadway. For this purpose, the motor vehicle expediently has corresponding wheels. In summary, it is preferably possible to position the motor vehicle essentially independently of other conditions on land. In other words, the motor vehicle is suitably not rail-guided. Preferably, the motor vehicle is a passenger car (car) or a commercial vehicle, such as a lorry (truck) or bus.

[0009] The drive unit is, for example, a component of a main drive of the motor vehicle, by means of which the motor vehicle is driven during operation. However, the drive unit is particularly preferably a component of an auxiliary unit of the motor vehicle, by means of which the motor vehicle is not directly driven. In particular, the drive unit is a component of an adjustment drive, such as an electric seat adjustment or an electric window lifter. Alternatively, the drive unit is, for example, a component of a pump, such as a water pump or an oil pump. In a further alternative, the drive unit is, for example, a transmission actuator, and the auxiliary unit is in particular a transmission. In a further alternative, the drive unit is, for example, a component of an air conditioning compressor.

[0010] Particularly preferably, however, the auxiliary unit comprising the drive unit is a steering system. For example, the drive unit forms a steering motor or at least the drive unit has the steering motor. During operation, the drive unit, for example, assists a steering movement performed by a driver. In other words, the steering system is mechanically designed, with a mechanical coupling between an operating device, such as a steering wheel, and steerable / controllable wheels or the like. Particularly preferably, however, the steering system is designed as a so-called "steer-by-wire" system, and in particular there is no direct mechanical operative connection between the operating device and the steerable / controllable wheels. The drive unit preferably acts on the steerable / controllable wheels via a rack or the like.The drive unit expediently has a gear that engages with the rack or is at least driven by the drive unit. Alternatively, a belt is driven by the drive unit. Preferably, the steering wheel or other operating device is assigned a sensor that is connected electrically and / or signal-wise to the drive unit. The connection is, for example, direct or via a control unit, by means of which the drive unit is operated based on the signals / data provided by the sensor. At least preferably, the drive unit is operated depending on the data and / or signals generated / provided by the sensor.

[0011] The drive unit comprises a support unit. The support unit is provided, for example, by a body or at least a part of the body of the motor vehicle or is rigidly attached to the body of the motor vehicle. In particular, the support unit serves as a support for further components of the assembly that includes the drive unit, in particular thus the auxiliary assembly. If the auxiliary assembly is the steering system, the support unit supports, for example, any steering rack and / or any steering column.

[0012] The drive unit further comprises an electric motor. For example, the electric motor is a brushed commutator motor. However, the electric motor is particularly preferably brushless and expediently a brushless direct current (BLDC) motor. This reduces any losses that may occur. The electric motor comprises a stator assembly comprising a stator. In particular, the stator comprises several magnets, expediently electromagnets. Each electromagnet expediently comprises an electric coil, wherein the individual coils are preferably connected to form several phases, in particular three phases. The stator assembly is expediently a self-supporting part and forms a module of the electric motor. In particular, the stator assembly comprises a housing, which is, for example, hollow-cylindrical or pot-shaped.The stator assembly is expediently surrounded circumferentially by the housing, and the stator is in particular fastened to the housing. The housing expediently extends parallel to an axial direction, which is also referred to as the axial direction, and which is preferably parallel to a rotational axis of the electric motor. Expediently, the housing, or at least the stator, is arranged concentrically to the rotational axis. In particular, the housing is made of aluminum and is preferably a die-cast aluminum part.

[0013] The electric motor further comprises a further assembly comprising a bearing plate. This further assembly is particularly self-supporting and forms another module of the electric motor. This makes it possible to adapt the electric motor to different applications, for example, by simply replacing or adapting one of the assemblies. This provides modularity, which reduces manufacturing costs and simplifies inventory management.

[0014] The electric motor preferably comprises a rotor which is operatively connected to the stator during operation. The rotor is expediently fastened to a shaft which, during operation, is set into a rotational movement due to an interaction between the stator and the rotor. In particular, the shaft is arranged concentrically and parallel to the axis of rotation. Suitably, the electric motor is designed as an internal rotor so that the stator surrounds the rotor on the circumference. The carrier unit has a receptacle into which the stator assembly is inserted. In particular, the receptacle surrounds the stator assembly completely or at least partially on the circumference. The stator assembly is thus at least partially stabilized by means of the receptacle. In particular, the stator assembly is not directly fastened to the carrier unit, but merely inserted into the receptacle, i.e. held loosely in the receptacle of the carrier unit, which simplifies assembly.

[0015] The bearing plate, on the other hand, is attached to the carrier unit. Due to the attachment of the bearing plate to the carrier unit, the stator assembly is closed by the bearing plate. In particular, the carrier unit positions the stator assembly in such a way that the stator assembly is closed by the bearing plate when the bearing plate is mounted on the carrier unit. Thus, the carrier unit serves to connect the electric motor to the other components of the motor vehicle. For example, a gearbox or other components driven by the electric motor are also mounted on the carrier unit.

[0016] Because the bearing shield is attached to the carrier unit, the position of the stator assembly is conveniently fixed. In particular, there is no direct attachment of the bearing shield to the stator assembly. This simplifies assembly and reduces manufacturing time. Consequently, manufacturing costs are reduced. Because the stator assembly is sealed by the bearing shield, the penetration of foreign particles into the stator assembly is prevented, which increases operational reliability. The escape of particles from the carrier unit and the stator assembly, such as to electronics, is also prevented, which increases operational reliability. In addition, since there is preferably no direct attachment of the bearing shield or other components to the stator assembly, no particles are created that could reduce operational reliability. In particular, the stator assembly is sealed dust-tight by the bearing shield, which increases operational reliability.For example, the stator assembly is at least partially encompassed by the bearing shield, which increases sealing. Due to the mutual engagement of the bearing shield and the stator assembly, they are expediently aligned with each other. The bearing shield is suitably aligned with respect to the carrier unit due to its attachment to the carrier unit. Consequently, the stator assembly is also aligned with respect to the carrier unit. In other words, the stator assembly is aligned with respect to the carrier unit by means of the bearing shield. This makes it possible to select comparatively high manufacturing tolerances in the area between the stator assembly and the carrier unit, which further reduces manufacturing costs.

[0017] For example, the stator assembly includes any housing that is inserted into the receptacle. However, the stator assembly particularly preferably has no housing and, in particular, is housingless. In this case, the housing is preferably formed by the carrier unit, in particular the receptacle.

[0018] For example, the bearing plate is riveted to the support unit. A wobble riveting process is expediently used for this. Due to the riveting, the bearing plate is permanently connected to the support unit, or at least detachment cannot occur without destruction, which increases robustness. For example, only one rivet is present here, or expediently two or three such rivets, so that a comparatively precise alignment of the bearing plate with respect to the support unit is achieved. However, the bearing plate is particularly preferably screwed to the support unit. For this purpose, in particular a screw is provided which is guided through the bearing plate, wherein the bearing plate is held in particular between the head of the screw and the support unit. For example, only a single screw is present here. However, it is particularly preferred that several screws are present, wherein the number of screws is expediently fewer than five.For example, there are exactly two or three such screws, ensuring a comparatively precise alignment of the bearing shield with respect to the carrier unit. Because of the screw connection, only minimal forces are required to attach the bearing shield to the carrier unit. At least the forces do not act directly on the bearing shield, the stator assembly, or the carrier unit. This prevents damage to these, which reduces scrap during production of the drive unit. It also makes it possible to use standard components, which reduces manufacturing costs. Furthermore, it is easier to detach the electric motor from the carrier unit if it develops a defect.

[0019] For example, the receptacle is open at the side and / or the receptacle is provided, for example, merely by means of an edge or the like, on which the stator assembly is aligned. However, the receptacle is particularly preferably pot-shaped or cylindrical. Thus, the receptacle in each case has at least one cylindrical section which is expediently arranged concentrically to and / or parallel to the axis of rotation of the electric motor. If the receptacle is pot-shaped, it expediently has a base which is suitably opposite the bearing plate, such that the stator assembly is arranged between the bearing plate and the base of the receptacle. To produce the drive unit, in particular the stator assembly is inserted into the receptacle and is in particular at least slightly stabilized there. This facilitates production.In this way, the stator assembly is also protected circumferentially by means of the carrier unit, which is why it is possible to reduce the robustness of the stator assembly, in particular of the possible housing of the stator assembly, or to dispense with it completely, which is why manufacturing costs and / or weight of the drive unit are reduced.

[0020] The receptacle, in particular the base of the pot-shaped receptacle, expediently comprises a recess through which a further component of the electric motor protrudes, suitably the shaft of the electric motor, if any. Expediently, a component of the drive unit, which is mounted, for example, on the support unit, is driven by means of the end protruding through the recess. For example, the stator assembly rests directly on any base. However, it is particularly preferred for the stator assembly to be supported there by means of a further element, by means of which, in particular, tolerance compensation is achieved. For example, the further element is a spring or the like, by means of which, in particular, a frictional connection is realized between the stator assembly and the bearing plate. Alternatively, the depth of the receptacle is adapted to the stator assembly. Alternatively, for example, the stator assembly projects beyond the receptacle.In this case, for example, the bearing shield does not lie flat on the support unit in the assembled state, and the screw / rivet is used to adjust the contact force of the bearing shield on the stator assembly.

[0021] For example, a press fit is created between the stator assembly and the holder, in particular in the circumferential direction. This increases robustness. However, it is particularly preferred that the stator assembly be mounted floating in the holder. In this case, for example, a clearance fit and / or a circumferential gap is formed between an inner side of the holder and the circumference of the stator assembly. This enables alignment of the stator assembly with respect to the carrier unit using the bearing shield. Also, if the electric motor and the carrier unit exhibit different thermal expansion during operation, the formation of excessive mechanical stresses is avoided, which could lead to destruction of the drive unit or impairment of the functionality of the drive unit. This increases robustness.The floating bearing affects, for example, all degrees of freedom or only a part, such as in a radial, tangential and / or axial direction.

[0022] The stator assembly is expediently supported circumferentially by means of springs on an inner wall of the receptacle. The springs are designed, for example, as leaf springs or wave springs. Preferably, the springs are each designed as radial springs. In particular, the springs also act as decoupling springs, so that any vibrations of the electric motor during operation, particularly due to any existing imbalance, are not transmitted to the carrier unit. This improves acoustics, while comparatively high manufacturing tolerances can still be selected. In summary, the stator assembly is preferably mounted in the receptacle on the springs, particularly in the radial and axial directions. In this case, an interference fit is provided, for example.In other words, the stator assembly, in particular the stator, is preferably pressed into the receptacle, with the springs providing support in the radial and / or axial direction, so that the stator is decoupled from the support unit. Suitably, the stator assembly, in particular the stator, comprises one or more grooves running parallel to the rotational axis, within which the springs are arranged.

[0023] Particularly preferably, the shaft is a component of the further assembly. In this case, the shaft is connected to the bearing shield by means of a bearing. The bearing thus forms in particular a component of the further assembly, and the bearing is expediently a rolling bearing, such as a ball bearing. In this case, the bearing is designed such that the shaft is held captively on the bearing shield. Thus, when the further assembly is assembled, the shaft is inserted into the stator assembly. In this way, it is also possible to align the shaft relatively precisely with respect to the bearing shield, so that it is in a desired position after the bearing shield has been assembled on the carrier unit. This ensures that the shaft is always in the desired position, whereby comparatively large manufacturing tolerances can be selected for the remaining components of the drive unit.

[0024] Particularly preferably, a further bearing is connected to the shaft and, in the assembled state, is inserted into a bearing seat of the stator assembly or, preferably, the holder of the carrier unit. This makes it possible to align the stator assembly relatively precisely by means of the bearing shield and the shaft held thereon. In particular, only a clearance fit is realized between the further bearing and the bearing seat, so that the further bearing only lies loosely in the bearing seat. Due to the clearance fit, the assembly of the further bearing is simplified and it is not necessary to insert additional tools or the like into the stator assembly. Also, for example, no additional processes for widening the fit by inductive heating are required. Advantageously, the holder is essentially pot-shaped, with the base in particular enclosing the bearing seat. Advantageously, the base forms the so-called A--side bearing shield.Preferably, the further assembly also includes any rotor, which is expediently arranged between the two bearings and is non-rotatably attached to the shaft. In other words, the rotor is a component of the further assembly, and the electric motor, in particular, comprises only the two assemblies.

[0025] For example, the bearing shield is circumferentially aligned with the stator assembly. However, the bearing shield particularly preferably has at least one tab that projects radially relative to the stator assembly. The radial direction is determined in particular with respect to the rotational axis of the electric motor. The tab is attached to the support unit. In particular, the tab comprises a hole through which the rivet or screw, if any, is guided. Alternatively, the tab is welded to the support unit, for example. Due to the projecting tab, the stator assembly is not undesirably influenced by any fastening element when the bearing shield is attached to the support unit. It is also not necessary, for example, to keep a space free in the stator assembly into which the screw, if any, would penetrate.This simplifies the design of the stator assembly, allowing it to be used for other applications, for example. On the other hand, the bracket provides a comparatively large lever arm relative to the rotor axis, allowing for a comparatively precise alignment of the bearing shield relative to the support unit and also relative to the desired rotation axis, especially if the shaft is attached to the bearing shield.

[0026] The electric motor particularly preferably comprises an electronic assembly, which expediently has electronics. In particular, the electronics serve to supply current to the stator of the stator assembly. For example, the electronic assembly is arranged separately from the bearing shield and / or the stator assembly and expediently fastened directly to the support unit. However, the electronic assembly is preferably fastened to the bearing shield. Thus, in particular, the bearing shield is closed on the side opposite the stator assembly by means of the electronic assembly, so that in particular the penetration of particles or the like via the bearing shield to the stator assembly is prevented. In this way, the requirements for the bearing shield are reduced, while tightness is nevertheless comparatively high. The electronics are expediently electrically contacted with the stator assembly, preferably with the stator.For this purpose, the bearing plate suitably has several bushings, in particular phase bushings, through which corresponding electrical cables are routed. The electronics assembly is expediently adapted to the stator used and preferably comprises a bridge circuit, for example, a B6 circuit. Suitably, the stator has two sets of three phases, each of which is connected, for example, in a star or delta configuration.

[0027] The invention further relates to an auxiliary unit. In the assembled state, the auxiliary unit is a component of a motor vehicle and is suitable, in particular provided and configured, for this purpose. The motor vehicle is, for example, land-based and, for example, a lorry, bus, or preferably a passenger car. The auxiliary unit has a drive unit with a carrier unit and an electric motor. The electric motor comprises a stator assembly and a further assembly that includes a bearing shield. The stator assembly is inserted into a receptacle of the carrier unit, wherein the bearing shield is fastened to the carrier unit in such a way that the stator assembly is closed by means of the bearing shield.

[0028] By means of the drive unit, preferably the electric motor, in particular another component of the auxiliary unit is driven, such as an adjustment part. This is, for example, mounted on the carrier unit or supported on it. For example, the drive unit is a component of an electric motor pump, such as a water pump, a coolant pump or a lubricant pump, for example an oil pump. For example, the auxiliary unit is a transmission. However, the auxiliary unit is particularly preferably a steering system. During operation, the drive unit acts, for example, to support a force applied manually by a driver. However, the steering system is particularly preferably designed as a "steer-by-wire" system. In this case, a mechanical fallback system is provided, which comprises, for example, a slip clutch. Alternatively, no mechanical fallback system is provided.By means of the drive unit or at least the electric motor, in particular a component is driven by means of which a steering angle of wheels of the motor vehicle is specified. In particular, a rack which is connected to at least one of the wheels of the motor vehicle is driven by means of the electric motor, wherein a steering angle of the associated wheel is specified by means of the position of the rack. For example, the rack is a component of the drive unit. Preferably, the rack is a component of the auxiliary unit or is driven by means of the auxiliary unit. In particular, the steering system comprises an operating device, such as a steering wheel, by means of which in particular the steering angle can be specified by a driver of the motor vehicle. Preferably, a signal-related coupling / connection between the drive unit and a sensor assigned to the operating device is provided.Alternatively, or in combination with this, the drive unit is coupled to an on-board computer or other assistance system of the motor vehicle, by means of which, in particular, semi-autonomous or fully autonomous movement, i.e., in particular steering, of the motor vehicle can be achieved. The invention also relates to a motor vehicle with such an auxiliary unit or at least with such a drive unit.

[0029] The method is used to create a drive unit of a motor vehicle, comprising a carrier unit and an electric motor. The electric motor comprises a stator assembly and a further assembly comprising a bearing plate. The stator assembly is inserted into a receptacle of the carrier unit, with the bearing plate being attached to the carrier unit in such a way that the stator assembly is closed by the bearing plate.

[0030] According to the method, the carrier unit is first provided. The carrier unit is preferably fastened to a body of the motor vehicle or provided therewith. At least the carrier unit has the receptacle. The stator assembly is inserted into the receptacle of the carrier unit. In particular, the stator assembly is not fastened to the carrier unit, and the two are in particular only loosely arranged relative to one another and, for example, only loosely abut one another. Preferably, the stator assembly is loosely mounted on the carrier unit in a direction parallel to the possible axis of rotation. Any springs are expediently present, and the stator assembly is suitably held on the carrier unit in a tangential direction with respect to the possible axis of rotation, i.e., rotationally, via the springs.In a radial direction with respect to the possible axis of rotation, i.e. perpendicular to it, the stator assembly is preferably decoupled from the carrier unit via the springs.

[0031] The bearing shield is then attached to the support unit in such a way that the stator assembly is closed by the bearing shield. For this purpose, the bearing shield is placed, in particular, on the support unit and / or the stator assembly. In particular, the bearing shield is not attached to the stator assembly; rather, they simply rest against one another, preferably in a force-fitting manner, so that a comparatively high level of sealing is achieved. Alternatively, or in combination with this, a sealing element is arranged between them. The bearing shield preferably encompasses the stator assembly at least partially on its circumference.

[0032] For assembly, the stator assembly is conveniently inserted into the support unit's receptacle from the side, where the bearing shield is subsequently attached to the support unit. This reduces the space required during production, and the assembly of the stator assembly and the bearing shield can be performed from the same side of the support unit. This can therefore be performed essentially one after the other and / or using the same machine. This reduces production time and the demands on the machines used for production.

[0033] The further developments and advantages explained in connection with the drive unit can also be transferred analogously to the auxiliary unit / the motor vehicle / the process as well as to each other and vice versa.

[0034] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawing: Fig. 1 schematically shows a motor vehicle with a steering system having a drive unit,

[0035] Fig. 2 shows a schematic sectional view of the drive unit,

[0036] Fig. 3 shows a perspective sectional view of the drive unit,

[0037] Fig. 4 shows a detail of an alternative embodiment of a part of the drive unit, and

[0038] Fig. 5 shows a method for producing the drive unit.

[0039] Corresponding parts are provided with the same reference numerals in all figures.

[0040] Figure 1 shows a simplified schematic representation of a motor vehicle 2 in the form of a passenger car (car). The motor vehicle 2 has a total of four wheels 4, which, in their intended state, rest on a roadway (not shown in detail), and which are connected to a body 6 of the motor vehicle 2 by means of a chassis. Two of the wheels 4, namely the two front wheels or, if applicable, the rear wheels, are coupled to an auxiliary unit 8, namely a steering system, by means of which a steering angle of these wheels 4 relative to the body 6 can be adjusted. For this purpose, the auxiliary unit 8 is operatively connected to these wheels 4. The auxiliary unit 8 comprises a drive unit 10, by means of which a rack (not shown in detail) is driven, which is mounted on the two front wheels.During operation of the drive unit 10, the rack is moved transversely, namely in a horizontal plane and perpendicular to a longitudinal axis of the motor vehicle 2, whereby due to the connection to the front wheels, their steering angle with respect to the body 6 is changed.

[0041] The auxiliary unit 8 further comprises a sensor 12 assigned to an operating device 14, wherein the position of the operating device 14 is detected by means of the sensor 12. The operating device 14 is designed as a steering wheel and arranged in an interior of the motor vehicle 2, which is provided by the body 6. The sensor 12 is signal-connected to the drive unit 10 via a control device / control unit (not shown in detail). There is no direct mechanical coupling between the operating device 14 and the front wheels of the motor vehicle 2, so the steering system is designed as a so-called "steer-by-wire" system.

[0042] Figure 2 shows a schematic sectional view of the drive unit 10, with an exploded view being chosen. Figure 3 shows a perspective sectional view of a section of the drive unit 10. The drive unit 10 has a support unit 16, which is rigidly connected to the body 6 or formed by a part thereof. The support unit 16 has a substantially pot-shaped receptacle 18, into which a stator assembly 20 of an electric motor 22 of the drive unit 10 is inserted.

[0043] The stator assembly 20 comprises a hollow cylindrical stator 24, which is arranged concentrically with a rotational axis 26, along which the section of the sectional view is taken, and which comprises several electromagnets (not shown in detail), each having an electrical coil. The electrical coils are electrically interconnected by means of a switching contact unit 28 of the stator assembly 20, forming a total of two sets of three phases. The switching contact unit 28 is mounted on the front side of the stator 24.

[0044] The stator assembly 20 is surrounded by an inner wall 30 of the receptacle 18. The inner wall 30 is formed by a cylindrical outer surface arranged concentrically to the rotational axis 26 of the electric motor 22. The stator 24 has one or more axial grooves, i.e., parallel to the rotational axis 26, in which grooves a plurality of springs 31 are arranged, by means of which the stator 24 is supported relative to the inner wall 30. The springs 31 are designed as radial springs, and by means of these, any manufacturing tolerances are compensated, so that even if the receptacle 18 is not completely concentric, a concentric arrangement of the stator assembly 20 is nevertheless possible. Any movement of the stator assembly 20 during operation is also carried out by means of the springs 31, so that only a slight or at least non-disturbing acoustic excitation of the carrier unit 16 or the electric motor 22 occurs.In summary, the stator assembly 20 is thus mounted in a floating or decoupled manner in the receptacle 18, for which purpose the stator assembly 20 is supported circumferentially by means of the springs 31 on the inner wall 28 of the receptacle 18.

[0045] A bottom of the cup-shaped receptacle 18 has a substantially round recess 34 arranged concentrically to the rotation axis 30, which forms a bearing seat 36.

[0046] Each phase of the stator 24 is assigned at least one phase connection 40 of the switching / contact unit 28, by means of which current can be supplied to the respectively assigned phase. Each phase connection 40 is provided by an electrical line, for example, a stamped and bent part, which has a substantially axial extension, i.e., parallel to the rotational axis 26.

[0047] The electric motor 22 further comprises a further assembly 41, which includes a bearing plate 42 arranged substantially perpendicular to the axis of rotation 26. A bearing 44, namely a ball bearing, is held on the bearing plate 42, although this is not shown in Figure 3. A shaft 46 is connected to the bearing plate 42 by means of the bearing 44. The shaft 46 is arranged concentrically to the axis of rotation 26 and is mounted by means of the bearing 44 so as to be rotatable about the axis of rotation 26 with respect to the bearing plate 42. The shaft 46 is a component of the further assembly 41, which additionally comprises a further bearing 48, which is also connected to the shaft 46 but is spaced apart from the bearing 44 in the axial direction. A rotor 50 is arranged between the two bearings 44, 48, which is arranged concentrically to the axis of rotation 26 and is connected to the shaft 46 in a rotationally fixed manner. In the assembled state, the rotor 50 is surrounded circumferentially by the stator 24.The further assembly 41 is formed by means of the bearing plate 42, the two bearings 44, 48 and the rotor 50, which, like the stator assembly 20, is present as a separate module.

[0048] The bearing plate 42 has a hollow cylindrical wraparound 52 on its circumference, by means of which the switching contact unit 28 is encompassed at the ends in the assembled state. In this case, each phase connection 40 extends through a corresponding bushing 54 of the bearing plate 42 and is located on the side of the bearing plate 42 opposite the rotor 50.

[0049] A tab 56 is formed on the wraparound portion 52, projecting outward in the radial direction relative to the rotation axis 26. Thus, the tab 56 also projects in the radial direction relative to the stator assembly 20. The tab 56 has an axially extending hole 58 through which a screw 60 is passed, which, in the assembled state, is screwed into a corresponding screw receptacle 62 in the support unit 16. The screw head of the screw 60 is located on the side of the tab 56 opposite the screw receptacle 62, which is thus arranged between the screw head and the support unit 16. The screw 62 is used solely to fasten the bearing plate 42 to the support unit 16, so that the bearing plate 42 is screwed to the support unit 16 in the assembled state.In particular, the support unit 16 has corresponding contours, by means of which an additional alignment of the bearing plate 42 with respect to the support unit 16 is achieved. Alternatively, several such screws 60 are provided, by means of which the bearing plate 42 is screwed to the support unit 16. In a further alternative, for example, the support unit and the bearing plate have alignment holes, which are brought into alignment with one another during the assembly process, so that a suitable alignment is achieved.

[0050] In summary, in the assembled state, at least the bearing plate 42 is fastened to the carrier unit 16. The arrangement and design of the hole 58, the screw 60, the screw receptacle 62, the wraparound portion 52, and the other components of the drive unit 10 are such that, in the screwed state, the stator assembly 20 is closed on the side opposite the bottom of the receptacle 18 by means of the bearing plate 42, with the wraparound portion 52 encompassing the ends of the stator assembly 20. In summary, the stator assembly 20 is inserted into the receptacle 18 of the carrier unit 16, with the bearing plate 42 being fastened to the carrier unit 16 in such a way that the stator assembly 20 is closed by means of the bearing plate 42. The drive unit 10 further comprises an electronics assembly 64, which, however, is not shown in Figure 3.The electronics assembly 64 has an electronics housing 66, which, in the assembled state, is attached to the bearing plate 42 or the support unit 16. For this purpose, the wraparound 52 is extended in the axial direction on the side opposite the stator assembly 20, and by means of this wraparound, the electronics housing 66 is encompassed. Thus, the electronics assembly 64 is arranged on the side of the bearing plate 42 opposite the stator assembly 20.

[0051] Arranged within the electronics housing 66 is an electronics unit 68 comprising a printed circuit board (not shown in detail) with a bridge circuit configured as a B12 circuit. In the assembled state, the phase terminals 40 are electrically contacted by the bridge circuit, and thus by the electronics unit 68, so that the stator 38 can be energized during operation by means of the electronics unit 68. In summary, the electronics assembly 64 is thus attached to the bearing plate 42, and the electronics unit 68 of the electronics assembly 64 is electrically contacted through the bearing plate 42 with the stator assembly 20.

[0052] Figure 4 shows a section of an alternative fastening variant of the bearing plate 42 to the carrier unit 16. The tab 56 with the hole 58 has not been changed. However, instead of the screw 60, a rivet 70 is now inserted therein. The rivet 70 is a component of the still one-piece carrier unit 16 and is located at the point where the screw receptacle 62 was located in the previous exemplary embodiment. The rivet 70 is initially cylindrical, as shown, and is widened at the end during the production process by means of wobble riveting. The end of the rivet 70 that passes through the hole 58 is widened such that its diameter is larger than the diameter of the hole 58, thus creating a permanent connection between the carrier unit 16 and the bearing plate 42. Figure 5 shows a method 72 for producing the drive unit 10.In a first work step 74, the support unit 16 is provided, which is already attached, preferably permanently, to another component of the body 6. The support unit 16 is already completely constructed and has the receptacle 18 as well as the screw receptacle 62 or the rivet 70.

[0053] In a subsequent second work step 76, the finished stator assembly 20 and the springs 31 are inserted into the receptacle 18 of the carrier unit 16. The stator assembly 20 is not fastened to the carrier unit 16. Due to the presence of springs 31, displacement and tilting of the stator assembly 20 with respect to the rotation axis 30 is possible to a limited extent. The stator assembly 20 is thus loosely mounted on the carrier unit 16 in a direction parallel to the rotation axis 26. In a tangential direction with respect to the rotation axis 26, i.e., rotationally, the stator assembly 20 is held on the carrier unit 16 by the springs 31. In the radial direction with respect to the rotation axis 26, i.e., perpendicular to it, the stator assembly 20 is decoupled from the carrier unit 16 by the springs 31.

[0054] In a subsequent third work step 78, the finished additional assembly 41, to which the electronics assembly 64 is already attached, is brought forward from the same side from which the stator assembly 20 was inserted into the receptacle 18. Alternatively, the electronics assembly 64 is not mounted until after the third work step 78. The shaft 46 is inserted into the stator 24 and is moved through the bearing seat 36 until the additional bearing 48 lies loosely in the bearing seat 36 and the bearing plate 42 rests against the carrier unit 16. In this case, the switching contact unit 28 is gripped by means of the grip 52. The phase connections 40 have corresponding plugs or the like that mechanically engage in corresponding counter-receptacles of the electronics 68, so that electrical contact is made with the electronics 68.

[0055] The bearing plate 42 is then attached to the support unit 16. Due to the attachment, the bearing plate 42 is aligned with respect to the support unit 16, whereby the stator assembly 20 is also aligned with respect to the bearing plate 42. As a result, the shaft 46 is concentric with the rotation axis.

[0056] 30. Furthermore, when the bearing plate 42 is attached to the support unit 16, the stator assembly 20 is closed by means of the bearing plate 42, and movement of the stator assembly 20 relative to the bearing plate 42 and the support unit 16 is no longer possible.

[0057] The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

[0058] List of reference symbols

[0059] 2 motor vehicles

[0060] 4 wheel

[0061] 6 Body

[0062] 8 Auxiliary unit

[0063] 10 Drive unit

[0064] 12 Sensor

[0065] 14 Control unit

[0066] 16 carrier unit

[0067] 18 recording

[0068] 20 Stator assembly

[0069] 22 electric motor

[0070] 24 Stator

[0071] 26 Rotation axis

[0072] 28 Switching contact unit

[0073] 30 interior wall

[0074] 31 spring

[0075] 34 recess

[0076] 36 bearing seat

[0077] 38 Stator

[0078] 40 phase connection

[0079] 41 additional modules

[0080] 42 Bearing shield

[0081] 44 camps

[0082] 46 Wave

[0083] 48 additional camps

[0084] 50 rotor

[0085] 52 wraparound

[0086] 54 Implementation

[0087] 56 tab

[0088] 58 holes

[0089] 60 Screw 62 Screw receptacle

[0090] 64 Electronic assembly

[0091] 66 electronics housings

[0092] 68 Electronics 70 Rivet

[0093] 72 procedures

[0094] 74 first step

[0095] 76 second step

[0096] 78 third step

Claims

Claims 1. Drive unit (10) of a motor vehicle (2), in particular of a steering system, with a carrier unit (16) and an electric motor (22) which has a stator assembly (20) and a further assembly (41) which comprises a bearing plate (42), wherein the stator assembly (20) is inserted into a receptacle (18) of the carrier unit (16), and wherein the bearing plate (42) is fastened to the carrier unit (16) in such a way that the stator assembly (20) is closed by means of the bearing plate (42).

2. Drive unit (10) according to claim 1, characterized in that the bearing plate (42) is screwed to the carrier unit (16).

3. Drive unit (10) according to claim 1 or 2, characterized in that the receptacle (18) is pot-shaped or cylindrical.

4. Drive unit (10) according to one of claims 1 to 3, characterized in that the stator assembly (20) is mounted floating in the receptacle (18).

5. Drive unit (10) according to claim 4, characterized in that the stator assembly (20) is supported circumferentially by means of springs (31) on an inner wall (28) of the receptacle (18).

6. Drive unit (10) according to one of claims 1 to 5, characterized in that the further assembly (41) comprises a shaft (46) which is connected to the bearing plate (42) by means of a bearing (44).

7. Drive unit (10) according to claim 6, characterized in that a further bearing (48) is connected to the shaft (46) and is inserted into a bearing seat (36) of the receptacle (18).

8. Drive unit (10) according to one of claims 1 to 7, characterized in that the bearing plate (42) has a tab (56) which projects in a radial direction with respect to the stator assembly (20) and is fastened to the carrier unit (16).

9. Drive unit (10) according to one of claims 1 to 8, characterized in that on the side of the bearing plate (42) opposite the stator assembly (20) there is arranged an electronic assembly (64) which is fastened to the bearing plate (42) and is electrically contacted with the stator assembly (20) through the bearing plate (42).

10. Method (72) for producing a drive unit (10) according to one of claims 1 to 9, in which - the carrier unit (16) is provided, - the stator assembly (20) is inserted into the receptacle (18) of the carrier unit (16), and - the bearing plate (42) is fastened to the support unit (16) in such a way that the stator assembly (20) is closed by means of the bearing plate (42).

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