End shield assembly of an electric motor

Abstract

The invention relates to an end shield assembly (36) of an electric motor (22), said end shield assembly comprising an end shield (38) that has a bearing seat (40) in which a bearing (42) is held. A cover cap (78) is attached to the end shield (38). The invention also relates to an electric motor (22).

Description

[0001] Description

[0002] End shield assembly of an electric motor

[0003] The invention relates to an end shield assembly of an electric motor, comprising an end shield. Furthermore, the invention relates to an electric motor.

[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, fully encapsulated unit. This prevents the ingress of foreign particles, which could otherwise damage the electric motor, during operation and during assembly to the other components of the vehicle. 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 and has an opening closed by a bearing plate. The individual components of the steering motor are inserted through this opening during assembly. To ensure the required tightness, the bearing plate is usually welded all the way to the housing.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 bearing shield assembly for an electric motor and a particularly suitable electric motor, wherein operational reliability is advantageously increased and manufacturing costs and / or manufacturing time are reduced. With regard to the bearing shield assembly, this object is achieved according to the invention by the features of claim 1 and with regard to the electric motor by the features of claim 10. Advantageous further developments and refinements are the subject of the respective subclaims.

[0008] In the assembled state, the bearing shield assembly is a component of an electric motor. In other words, the bearing shield assembly at least partially forms the electric motor when used as intended. The electric motor is expediently a component of a motor vehicle. In other words, the electric motor is suitable, in particular provided and configured, to form a component of the motor vehicle in the assembled state. The motor vehicle is in particular land-based and preferably has a multi-track design. 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 electric motor 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 electric motor is particularly preferably a component of an auxiliary unit of the motor vehicle, by means of which the motor vehicle is therefore not directly driven. In particular, the electric motor is a component of an adjustment drive, such as an electric seat adjustment or an electric window lifter. Alternatively, the electric motor is, for example, a component of a pump, such as a water pump or an oil pump. In a further alternative, the electric motor is, for example, a component of a transmission actuator, and the auxiliary unit is, in particular, a transmission. In a further alternative, the electric motor is, for example, a component of an air conditioning compressor. However, the auxiliary unit that comprises the electric motor is particularly preferably a steering system.For example, the electric motor forms a steering motor. When operated, the electric motor, 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 / steerable wheels or the like. However, the steering system is particularly preferably 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 / steerable wheels. The electric motor preferably acts on the steerable / steerable wheels via a rack or the like. Expediently, a gearwheel that engages with the rack is driven by the electric motor.Preferably, a sensor is assigned to the steering wheel or other control device, which is connected electrically and / or signal-wise, in particular, to the electric motor. The connection is, for example, direct or via a control unit, by means of which the electric motor is operated based on the signals / data provided by the sensor. At least preferably, the electric motor is operated depending on the data and / or signals generated / provided by the sensor.

[0010] The bearing shield assembly is suitable, in particular intended and configured, for mounting on other components of the electric motor. In particular, the bearing shield assembly comprises suitable components for this purpose or is at least partially shaped accordingly. In the assembled state, a housing of the electric motor is expediently closed by the bearing shield assembly.

[0011] The bearing shield assembly has a bearing shield, which is made in particular from a metal, for example aluminum or steel. The bearing shield is expediently designed to be essentially flat and, in the assembled state, is arranged in particular perpendicular to a rotational axis of the electric motor. The bearing shield has a bearing seat in which a bearing is held. The bearing is, for example, a plain bearing or particularly preferably a rolling bearing, expediently a ball bearing or a needle bearing. The bearing seat is formed, for example, by means of a substantially round receptacle in which the bearing is fastened, in particular an outer ring of the bearing, provided that this is designed as a rolling bearing. For example, the bearing is fastened to the bearing shield by means of adhesive or the bearing is pressed into the bearing seat, such that a frictional connection is realized between the bearing and the bearing shield.In a further alternative, the bearing is attached to the bearing shield by means of a radial clearance fit and axial caulking. Due to the bearing seat, the shape of the bearing shield is expediently ring-shaped or disc-shaped. The bearing expediently serves to rotatably support a shaft. At least the bearing is suitable, in particular provided and configured, to rotatably support such a shaft. The shaft is, for example, a component of the bearing shield assembly or at least of the electric motor. In the assembled state, a rotor of the electric motor is expediently fastened to the shaft in a rotationally fixed manner. The bearing seat and the bearing are designed in particular such that, on the one hand, the shaft is arranged concentrically to the axis of rotation by means of them. On the other hand, the shaft is rotatably mounted with them about the axis of rotation. Preferably, the axis of rotation is at least partially predetermined by means of the bearing seat and / or the bearing.

[0012] The bearing shield assembly further comprises a cover cap attached to the bearing shield. Thus, a space is formed by the cover cap and the bearing shield, the boundary of which is provided in particular by the cover cap and the bearing shield. Consequently, components arranged in the space are covered by the cover cap and protected by the cover cap and the bearing shield. Preferably, the space formed by the cover cap and the bearing shield is separated from the environment in a dust-tight and / or splash-tight manner.

[0013] The cover cap prevents dirt particles or similar from penetrating the components covered by the cover cap, thus increasing operational reliability. This eliminates the need for separate or additional encapsulation of the components covered by the cover cap, thus reducing material costs. In other words, it is not necessary to provide additional encapsulation for the covered components, nor does it require a particularly robust design, thus reducing manufacturing costs. In addition to preventing the penetration of dirt particles / foreign particles, the components are also protected from mechanical damage, particularly during assembly of the electric motor.In summary, no removal of dirt particles is required when assembling the electric motor, and due to the mechanical protection, a comparatively quick assembly of the bearing shield assembly to other components of the electric motor is possible.

[0014] Since only small manufacturing tolerances are acceptable for the bearing shield (otherwise, for example, the shaft supported by the bearing would not be concentric with the rotational axis), the bearing shield requires comparatively extensive remachining. In this context, it is possible to design appropriate mounting or fastening points for the cover cap on the bearing shield with essentially no additional time expenditure, or at least with only minimal time expenditure, thus not significantly increasing production time. To install the cover cap, preferably only appropriate positioning relative to the bearing shield is required.

[0015] For example, the entire bearing shield is covered by the cover cap. The cover cap thus has at least the extent of the entire bearing shield, expediently perpendicular to the axis of rotation. Alternatively, only a section of the bearing shield is covered by the cover cap. Preferably, a particle insulation paper is attached to the bearing shield, preferably on the side opposite the cover cap. The particle insulation paper is used, in particular, to ensure a seal on the opposite side of the bearing shield. Alternatively, or in combination with this, the particle insulation paper or another particle insulation paper is also at least partially covered by the cover cap. The cover cap thus protects the bearing shield, which increases robustness.

[0016] In particular, the cover cap is made of a plastic and consists, for example, only of a plastic body. Preferably, the cover cap, or at least the plastic body, is a plastic injection-molded part, which means that manufacturing costs are comparatively low. The cover cap expediently comprises additional components that provide additional functions.

[0017] For example, the cover cap is permanently connected to the bearing shield. For example, an adhesive connection or, expediently, a riveted connection is used for this purpose. In particular, one or more rivets are attached to the bearing shield, which are preferably integral with other components of the bearing shield, so that they are molded onto it. Riveting is carried out, for example, using a wobble riveting process. This type of attachment increases robustness, and the cover cap is held securely to the bearing shield even when the electric motor is subjected to vibrations, thus safely protecting the components it covers.

[0018] Alternatively, the cover cap is detachably connected to the bearing shield. For example, the cover cap is clipped to the bearing shield. For example, the cover cap comprises an undercut by means of which the bearing shield, preferably the edge, is gripped. Alternatively, the bearing shield has, for example, one or more components of a snap-in connection by means of which the cover cap is secured. In a further alternative, the cover cap is fastened to the bearing shield, for example by means of screws, so that the cover cap is screwed to the bearing shield. Due to the detachable fastening, it is therefore possible to replace covered components in the event of damage or a fault, thus simplifying repairs. Alternatively, or in combination with this, the cover cap is used, for example, solely for the assembly of the electric motor.In this case, the cover cap is fastened to the bearing shield until the bearing shield assembly is fastened to other components of the electric motor, in particular to another assembly, or to other components of the motor vehicle. For example, the cover cap is removed to enable fastening. In particular, after the cover cap has been loosened, another component of the electric motor or at least of the motor vehicle is arranged in its position, so that in this case the protective function is realized by means of the other component. Alternatively or in combination with the protection of the covered components, a component of the bearing shield assembly, for example the shaft, is stabilized by means of the cover cap, so that no rotational movement occurs. In summary, the shaft or the other component is preferably inhibited by means of the cover cap, for example directly or via other components.This simplifies the assembly of the bearing shield assembly to other components of the electric motor. Once the bearing shield assembly is installed, the cover cap is removed, releasing the component it holds / locks. This allows for subsequent uninterrupted operation of the electric motor. In summary, the cover cap is primarily used as a transport lock.

[0019] For example, the bearing shield is essentially smooth, at least in the area where contact with the cover cap occurs. For example, the cover cap rests mechanically directly on the bearing shield. However, it is particularly preferred that the cover cap rests on the bearing shield via a sealing element. This compensates for any unevenness, in particular of the cover cap, while still achieving a high level of sealing. It is therefore possible to select comparatively high manufacturing tolerances when manufacturing the cover cap. This reduces manufacturing costs. For example, the sealing element is held force-fitting between the cover cap and the bearing shield. The bearing shield particularly preferably has a receptacle by means of which the sealing element is held. This stabilizes the position of the sealing element and facilitates the subsequent fastening of the cover cap.In particular, the receptacle is formed, at least in sections, by a groove. Due to the post-processing of the bearing shield, the groove can be created in the same work step, thus essentially requiring no additional manufacturing time. The sealing element can be a solid, such as a rubber or elastomer. Alternatively, the sealing element is liquid during production and only hardens after the cover cap is attached. In this case, the receptacle prevents uncontrolled distribution of the still-liquid sealing element during production, thus preventing contamination of the bearing shield assembly.

[0020] The bearing shield expediently has one or more passages through which one or more phase connections are led in the assembled state. These are, for example, a component of the bearing shield assembly or separate therefrom. By means of the phase connections, a stator of the electric motor is expediently electrically contacted through the bearing shield with electronics arranged on the other side of the bearing shield in the assembled state. In other words, the electronics and the stator are arranged on different sides of the bearing shield in an axial direction that is in particular parallel to the axis of rotation. For example, the passage is not covered by the cover cap. However, the passage for the phase connection is particularly preferably covered by the cover cap.If multiple passages are present, for example, each passage is assigned a corresponding cover cap, or all passages are covered by the single cover cap. For example, the passages on the side opposite the cover cap are closed with another component, such as a membrane or the like. Alternatively, the phase connections are already arranged in the passages. The stator is conveniently present in this case. The arrangement of the cover cap prevents dirt particles from penetrating the stator, thus increasing operational reliability.

[0021] Alternatively, or in combination with this, the bearing is covered by the cover cap. The bearing is thus at least partially protected by the cover cap. In this case, the cover cap is, for example, permanently connected to the bearing shield or is at least left on the bearing shield after the electric motor has been manufactured, i.e. when the electric motor is in operation. In particular, the bearing shield forms a B-side bearing shield, so that the cover cap does not impede any components driven by the electric motor. The cover cap reduces the demands on the bearing, which is why a comparatively cost-effective bearing can be used. Alternatively, the cover cap is removed, for example, during the manufacture of the electric motor or at least after the bearing shield assembly has been mounted on other components.Until then, for example, the shaft is blocked by the cover cap, preventing any rotational movement, which simplifies assembly to the other components. The cover cap also keeps any dirt particles that may be generated during assembly of the bearing shield assembly to the other components away from the bearing, ensuring that the bearing's functionality is not impaired.

[0022] Particularly preferably, a sensor system for determining the position of any shaft supported by the bearing is connected to the bearing shield. The sensor system is thus suitable, in particular provided and configured, to determine the position of the shafts, in particular an angular position of the shaft with respect to other components of the bearing shield. The sensor system expediently comprises a corresponding sensor, for example one or more Hall sensors or a combination of several corresponding sensors. The sensor system is preferably covered by the cover cap. The cover cap is left in place, for example, only for transport of the bearing shield assembly and / or until it is mounted on other components of the electric motor. Thus, the cover cap protects the sensor system from dirt and foreign particles and / or mechanical damage during installation / assembly, which reduces rejects.It is also unnecessary to design the sensors to be comparatively robust. When installed, the sensors are conveniently protected by other components of the electric motor, such as an electronic assembly or other components. Removing the cover cap allows for essentially uninterrupted operation of the sensors. It is not necessary to adapt the cover cap to the sensor's operation, allowing the design to be comparatively cost-effective.

[0023] Alternatively, the cover cap remains on the bearing plate even after assembly, so that the sensor is covered by the cover cap even when the electric motor is in operation. This keeps dirt particles or existing cables that arise during operation of the electric motor away from the sensor, enabling comparatively safe operation. Alternatively, the cover cap shields the sensor from electromagnetic fields generated during operation. This improves the accuracy of determining the shaft position. In particular, the cover cap is designed accordingly and has, for example, a metal layer. The cover cap expediently encloses the plastic body, which is metallized.

[0024] The connection of the sensor system to the bearing shield, which serves to determine the position of the shaft supported by the bearing, is particularly independent of the cover cap and is considered a separate invention. In other words, the invention thus also relates solely to the bearing shield assembly with the bearing shield, which has the bearing seat in which the bearing is held, with the sensor system for determining the position of the shaft supported by the bearing being connected to the bearing shield.

[0025] For example, a component of the sensor system is attached to the shaft, the position of which is detected by means of further components of the sensor system. However, the sensor system particularly preferably comprises a component which is driven by the shaft and rotatably mounted by means of the bearing shield. In particular, a gear is mounted on the shaft, and the driven component comprises a further gear which engages with the gear mounted on the shaft. Thus, when the shaft rotates, the driven component also rotates. The driven component is mounted in particular by means of the bearing shield so that it can rotate about an axis which is parallel to the rotational axis of the shaft. The mounting on the bearing shield is achieved, for example, by means of a pin / axle which is attached to the bearing shield. The pin / axle is made, for example, from steel and is held by means of a corresponding pin-axle holder of the bearing shield.Preferably, the journal / axle is pressed into the journal-Z-axis receptacle. This reduces restrictions on the choice of material for the journal / axle. Alternatively, the journal / axle is made integrally with other components of the bearing shield. This means that the journal / axle is created during production of the bearing shield, which reduces production time. This also increases robustness. In a further alternative, the bearing shield comprises a further bearing seat in which a further bearing is arranged. The further bearing seat is offset outwards with respect to the bearing seat in a radial direction determined with respect to the axis of rotation, and the driven component is mounted by means of the further bearing. The further bearing is in particular a rolling bearing. For example, only a single such driven component is present.The driven component makes it possible to manufacture the other components of the sensor system essentially independently of the shaft. This also prevents any imbalance from being introduced into the shaft. For example, only a single driven component is present. However, it is particularly preferred to have several such driven components, for example, two driven components, each of which is assigned a corresponding sensor. This enables a comparatively precise determination of the shaft position, particularly allowing the use of comparatively cost-effective sensors.

[0026] Both the shaft / bearing shield and the driven component are expediently covered by the cover cap. This prevents the penetration of foreign particles into the area of ​​the gearing, thus increasing the accuracy of determining the shaft position. In particular, the cover cap fixes the driven component as long as the cover cap is attached to the bearing shield. This means that when the bearing shield assembly is mounted on other components of the electric motor, the driven component is held in place, which simplifies assembly. It also prevents damage to the sensors during assembly and transport, even in the event of vibrations to the bearing shield assembly. Furthermore, subsequent calibration of the sensors is made easier, as the driven component is in a predefined position after the cover cap is removed.

[0027] Particularly preferably, the electric motor comprises a stator assembly comprising a stator and, expediently, a housing that surrounds the stator. The housing is expediently made of aluminum. For example, the housing is hollow-cylindrical and extends parallel to the rotation axis. Particularly preferably, the housing is cup-shaped, and a further bearing, which also supports any shaft, is held by the housing, in particular a cup base.

[0028] In particular, in the assembled state, the stator is arranged concentrically to the axis of rotation. Preferably, the stator comprises one or more magnets, expediently electromagnets, each of which encloses a corresponding electrical coil. In particular, the electrical coils are electrically connected to form several phases, expediently three phases or twice three phases (6-phase system), so that redundancy is provided. The connection is made in particular by means of a switching / contact unit that is placed on the front side of the stator. Suitably, in the assembled state, the housing is closed by means of the bearing shield. Alternatively, for example, the housing is not present and the electric motor is housingless. For example, the housing or at least the switching / contact unit is at least partially encompassed by means of the bearing shield.

[0029] The bearing plate suitably has a mounting opening for receiving a mounting element of the stator assembly, in particular a switching / contact unit of the stator assembly. In the assembled state, a mounting element is guided through the mounting opening, with a press fit or preferably a clearance fit being formed between them, for example, so that assembly is facilitated. Preferably, the mounting opening and / or the mounting element run essentially parallel to the axis of rotation. At least in the assembled state, the mounting element is arranged in the mounting opening and is suitable, in particular provided and configured, for this purpose. The mounting element serves, for example, to fasten the stator assembly to the bearing plate. For example, the mounting element is a rivet or a screw.The screw is guided through the mounting hole, particularly from the side opposite the stator assembly, and screwed to the stator assembly. Thus, the bearing plate is located between the screw head and the stator assembly. If the mounting element is a rivet, it is specifically attached to the stator assembly and guided through the mounting hole for assembly. The end of the rivet guided through the mounting hole is then widened, creating a permanent connection between the bearing plate and the stator assembly.

[0030] Alternatively or in combination with attachment to the stator assembly, the mounting element serves to align the stator assembly with respect to the bearing shield assembly, in particular with respect to the bearing shield, thereby reducing effort. For this purpose, the mounting element rests circumferentially on the inside of the mounting opening. Since the bearing shield is already remachined, it is possible to manufacture the mounting opening with comparatively small manufacturing tolerances, which means that the stator assembly is aligned comparatively precisely with respect to the bearing shield. In contrast, comparatively high manufacturing tolerances can be selected for the other components of the electric motor. This reduces manufacturing costs, and the axis of rotation of the resulting electric motor is located at the desired position relative to the stator assembly and the bearing shield.In particular, due to the mounting element, the stator assembly or at least the stator of the stator assembly is arranged concentrically to the axis of rotation, which is predetermined by means of the bearing.

[0031] Since the mounting opening is provided by the bearing shield, an additional function is provided by the bearing shield assembly, and assembly of the electric motor is simplified. For example, only a single mounting opening is present. Particularly preferably, the bearing shield comprises a plurality of such mounting openings, of which, for example, only one is used. In other words, only a single mounting element is present in the assembled state. Due to the multiple mounting openings, it is possible to use different stator assemblies, so that different electric motors can be manufactured, although identical parts can still be used. Alternatively, a mounting element is arranged in each mounting opening in the assembled state. These are, for example, designed in the same way, or some of them are used for fastening and others merely for alignment.The mounting opening is conveniently covered by the cover element, at least until it is mounted on the stator assembly. This prevents foreign particles from entering the mounting opening until assembly. After assembly, the mounting opening is closed by the mounting element, ensuring continued tightness. Thus, the cover cap is no longer required in this case.

[0032] For example, in the assembled state, the bearing shield is fastened to any stator assembly. The electric motor is mounted to other components, in particular of the motor vehicle, for example by means of any housing. However, it is particularly preferred to have a tab attached to the bearing shield that projects in the radial direction, wherein the radial direction is determined in particular with respect to the axis of rotation. In this case, the tab projects in particular beyond any stator assembly or at least any housing in the radial direction, which is closed by the bearing shield in the assembled state. The tab itself has an opening for receiving a fastening element, wherein the fastening element, in its intended state, serves for fastening to a carrier unit. In particular, the carrier unit is a component of any motor vehicle and is formed, for example, by a body of the motor vehicle.In particular, a component driven by the electric motor is mounted on the carrier unit. Preferably, the carrier unit and the electric motor form a drive unit. In the assembled state, the fastening element is arranged in the opening. For example, the fastening element is a rivet or a screw. Particularly preferably, the bearing shield assembly is not fastened to the possible stator assembly, but rather the stator assembly is, in particular, correspondingly aligned, fastened to it, or at least held by means of the carrier unit. The assembly to form the electric motor takes place in particular by fastening the bearing shield assembly to the carrier unit, wherein there is preferably no fastening to the stator assembly. For example, the tab is fastened to the bearing shield and, for example, made of a different material.However, it is particularly preferred that the tab be molded onto the bearing plate and thus be integral with it. Consequently, the tab is also reworked during the remachining of the bearing plate, allowing comparatively tight manufacturing tolerances to be selected for the opening without significantly increasing production time. This also allows the electric motor to be attached, or at least mounted, to the support unit with comparatively high precision.

[0033] For example, the electric motor is a brushed commutator motor. However, the electric motor is particularly preferably designed to be brushless and expediently a brushless direct current (BLDC) motor. This reduces any losses that occur. The electric motor comprises a housing and a bearing shield assembly. The bearing shield assembly comprises a bearing shield having a bearing seat in which a bearing is held, with a cover cap attached to the bearing shield. The housing is closed by the bearing shield assembly, expediently by the bearing shield. The cover cap is preferably located on the side of the bearing shield facing away from the housing. This allows subsequent removal. Suitably, the housing is a component of a stator assembly that comprises a stator. In particular, the stator has a plurality of magnets, expediently electromagnets.Each electromagnet expediently comprises an electrical coil, wherein the individual coils are preferably connected to form multiple phases, in particular three phases or twice 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 the 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 an aluminum die-cast part.

[0034] 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 an electric motor. The electric motor comprises a housing and a bearing shield assembly. The bearing shield assembly comprises a bearing shield having a bearing seat in which a bearing is held, with a cover cap fastened to the bearing shield. The housing is closed by means of the bearing shield assembly. Expediently, the auxiliary unit also has a carrier unit to which the electric motor is fastened. In particular, the electric motor and the carrier unit form a drive unit.

[0035] In particular, another component of the auxiliary unit, such as an adjustment part, is driven by the electric motor. This is, for example, mounted on the carrier unit or supported on it. For example, the electric motor is a component of an electromotive pump, such as a water pump, a coolant pump, or a lubricant pump, such as an oil pump. For example, the auxiliary unit is a transmission. However, the auxiliary unit is particularly preferably a steering system. During operation, the electric motor, for example, supports a force applied manually by a driver. However, the steering system is particularly preferably designed as a steer-by-wire system. The electric motor drives a component 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 the position of the rack determines the steering angle of the associated wheel. Preferably, the rack is a component of the auxiliary unit or is driven by the auxiliary unit. In particular, the steering system comprises an operating device, such as a steering wheel, by means of which the steering angle can be specified by a driver of the motor vehicle. Preferably, a signal-technical coupling / connection of the electric motor to a sensor associated with the operating device is present. Alternatively or in combination with this, the electric motor is coupled to an on-board computer or other assistance system of the motor vehicle, by means of which, in particular, semi-autonomous movement of the motor vehicle can take place.The invention also relates to a motor vehicle with such an auxiliary unit or at least with such an electric motor. The invention also relates to a drive unit comprising the electric motor and the support unit, wherein the electric motor is attached to the support unit, preferably the bearing plate assembly.

[0036] The further developments and advantages explained in connection with the bearing shield assembly can also be transferred analogously to the electric motor / the auxiliary unit / the motor vehicle / the drive unit as well as to each other and vice versa.

[0037] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings:

[0038] Fig. 1 schematically shows a motor vehicle with a steering system having a drive unit,

[0039] Fig. 2 shows a schematic sectional view of the drive unit, which comprises an electric motor,

[0040] Fig. 3 a perspective sectional view of a section of the bearing shield assembly Fig. 4 perspective a variant of the bearing shield assembly of the electric motor,

[0041] Fig. 5, 6 in a perspective sectional view, partial alternative embodiments of the bearing shield assembly,

[0042] Fig. 7 shows a schematic, semi-transparent representation of another variant of the bearing shield assembly,

[0043] Fig. 8 shows an enlarged section of the bearing plate assembly according to Fig. 7,

[0044] Fig. 9, 10 in perspective and in a plan view a further embodiment of the electric motor and

[0045] Fig.11 perspective view of a stator of the electric motor.

[0046] Corresponding parts are provided with the same reference numerals in all figures.

[0047] 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 possibly 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.

[0048] The auxiliary unit 8 further comprises a sensor 12, which is 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 that the steering system is designed as a so-called "steer-by-wire" system.

[0049] Figure 2 shows a schematic sectional view of the drive unit 10, although an exploded view has been chosen. The drive unit 10 has a support unit 16 which is rigidly connected to the body 6 or formed by means of 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. The stator assembly 20 is, for example, pressed / shrunk directly into the receptacle or inserted into the receptacle 18 via springs. The stator assembly 20 comprises a substantially hollow-cylindrical stator 24 which is arranged concentrically to a rotational axis 28 and which comprises a plurality of electromagnets (not shown in detail), each of which has an electrical coil.The electrical coils are electrically interconnected by means of a switching contact unit 30 of the stator assembly 20, which is mounted on the front side of the stator 24, forming a total of two three-phase connections. Each of the phases is assigned at least one phase connection 35, by means of which the respective associated phase can be energized. Each phase connection 35 is provided by an electrical line, for example, a stamped and bent part, which has a substantially axial extension, i.e., parallel to the rotation axis 28.

[0050] The electric motor 22 further comprises a bearing plate assembly 36, which includes a bearing plate 38 arranged substantially perpendicular to the rotational axis 28. The bearing plate 38 has a bearing seat 40, namely a round recess arranged concentrically to the rotational axis 28. A bearing 42, namely a ball bearing, is held in the bearing seat 40. A shaft 44 is connected to the bearing plate 38 by means of the bearing 42. The shaft 44 is arranged concentrically to the rotational axis 28 and is mounted by means of the bearing 42 for rotation about the rotational axis 28 with respect to the bearing plate 38.

[0051] The shaft 44 is, for example, a component of the bearing shield assembly 36 or, for example, a rotor assembly. A rotor 46 arranged concentrically to the rotation axis 28 is rotatably mounted on the shaft 44, as well as a second bearing 48, with the rotor 46 located between the two bearings 42, 48. In the assembled state, the rotor 46 is circumferentially surrounded by the stator 34, with the second bearing 48 resting in a second bearing seat 49 that is inserted into the bottom of the cup-shaped receptacle 18.

[0052] The bearing plate 38 has a hollow cylindrical wraparound 50 on its circumference, which, in the assembled state, surrounds the switching contact unit 30 at its ends. Each phase connection 35 then extends through a corresponding passage 52 of the bearing plate 42 and is located on the side of the bearing plate 42 opposite the rotor 46.

[0053] A tab 54 is formed on the wraparound portion 50, projecting outward in the radial direction relative to the rotation axis 28. Thus, the tab 54 also projects in the radial direction relative to the stator assembly 20. The tab 54 has an opening 56, which is designed as a hole running in the axial direction. In the assembled state, a fastening element 58, namely a screw, is received in the opening 56. By means of the fastening element 58, the bearing shield assembly 36 is fastened to the carrier unit 16 in the assembled state, for which purpose the screw is screwed into a corresponding screw receptacle 60 in the carrier unit 16. The screw head of the screw is located on the side of the tab 54 opposite the screw receptacle 60, which is thus arranged between the screw head and the carrier unit 16.In summary, the tab 54, which projects in the radial direction, is connected to the bearing plate 38 and includes the opening 56 for receiving the fastening element 58 for attachment to the support unit 16. Figure 3 shows the bearing plate assembly 36 in a perspective sectional view along the axis of rotation 28. A gear 62 is mounted on the shaft 44 on the side opposite the rotor 46 and is connected in a rotationally fixed manner to the shaft 44. A further gear 64 of a driven component 66 is in engagement with the gear 62. The further gear 64 is mounted on a further shaft 68 and fastened thereto in a rotationally fixed manner. The further shaft 68 is mounted for rotation about a further axis of rotation 74 by means of a further bearing 70, which is held in a further bearing seat 72 of the bearing plate 38. The further rotation axis 74 is parallel to the rotation axis 28, but offset radially outwards with respect to it.

[0054] The driven component 66 is part of a sensor system 76 which serves to determine the position of the shaft 44. For this purpose, the position of the further shaft 68 is determined by means of a sensor shown in more detail. The position of the shaft 44 is then determined based on the gear ratio specified by the two gears 62, 64. Depending on the selection of the gear ratio, a more precise position determination is possible than if the position of the shaft 44 were determined directly by means of the sensor. In summary, the sensor system 76 for determining the position of the shaft 44 mounted by means of the bearing 42 is connected to the bearing plate 38 on the side opposite the rotor 46. For this purpose, the driven component 66 is driven by the shaft 44 via the gear 62, which is rotatably mounted by means of the bearing plate 38, namely the further bearing 70 inserted in the further bearing seat 72.

[0055] The bearing plate assembly 36 further comprises a substantially pot-shaped cover cap 78, which is attached to the bearing plate 38. The cover cap 78 is made of a plastic and is an injection-molded part. The cover cap 78 is permanently connected to the bearing plate 38. For this purpose, the bearing plate 36 has a receptacle 80 in the form of a groove, which mimics the edge of the opening of the cover cap 78, which lies in a common plane, and in which a sealing element 82 is held. The sealing element 82 is an adhesive that is liquid during the manufacture of the bearing plate assembly 36, so that the cover cap 78 is glued to the bearing plate 38. The sealing element 82 thus serves to seal and secure the cover cap 78.

[0056] By means of the cover cap 78 and a part of the bearing plate 38, an enclosed space is formed within which the sensor system 76 is arranged. Thus, the sensor system 76 is covered by the cover cap 78. The gear 62, the end of the shaft 44 protruding through the bearing plate 38, as well as the bearing seat 40 and the bearing 42 are also covered by the cover cap 78. This prevents dirt particles / foreign particles from accumulating between the two gears 62, 64 or other components of the sensor system 76, which is why a comparatively accurate determination of the position of the shaft 44 by means of the sensor system 76 is possible over the entire service life.

[0057] In a variant not shown in more detail, the sealing element 82 is present as a solid body when it is inserted into the receptacle 82. The sealing element 82 is made, for example, from a rubber or elastomer. In this case, the cover cap 78 is fastened to the bearing shield 36 in some other way. In a further variant not shown in more detail, the cover cap 78 is only left on the bearing shield 78 up to a certain point in the assembly of the electric motor 22. For example, the cover cap 78 is removed when the bearing shield assembly 36 has been or will be fastened to the stator assembly 20. Instead of the cover cap 78, an electronic assembly of the electric motor 22 (not shown in more detail) is at least partially arranged there, which electronic assembly, for example, has further components of the sensor system 76 or further components that interact with the sensor system 76.The electronics also electrically contact the phase terminals 35, and during operation, the stator 34 is thus supplied with current via the electronic assembly. In the previously mentioned embodiments, the passages 52 are not covered by the cover cap 78. In a variant not shown in detail, however, the cover cap 78 is enlarged, so that the passages 52 are also covered by the cover cap 78. Figure 4 shows a perspective view of an alternative embodiment of the bearing shield assembly 36, wherein the sensor system 76 with the driven component 66 is still present, which is rotatably mounted about the further rotational axis 74 by means of the bearing shield 38. The cover cap 78, on the other hand, is essentially flat and rests on a collar 84 formed on other components of the bearing shield 38. The collar 84 runs parallel to the rotational axis 28 and extends to the end of the overlap 50.In other words, the overlap 50 and the collar 84 end in a common plane. The cover element 78 is attached to the bearing plate 38 by means of several screws 86. Thus, the cover cap 78, which is made of a plastic, is detachably connected to the bearing plate 38.

[0058] Figure 5 shows an alternative embodiment of the bearing plate assembly 36, corresponding to the illustration in Figure 3, wherein the phase connections 35 are also shown here, each of which is arranged in one of the passages 52. The shaft 44 is also present, which is shown semi-transparent, and the gear 62 is mounted on this. By means of this, the further gear 64 of the driven component 66, which is rotatably mounted by means of the bearing plate 38, continues to be driven. However, an additional gear 88 of an additional driven component 90 is now also driven. With the exception of the transmission ratio between the additional gear 88 and the gear 62, the additional driven component 90 is structurally identical to the driven component 66, which is why it is also rotatably mounted by means of the bearing plate 38.A corresponding sensor is also assigned to the additional driven component 90. The cover cap 78 is not shown, but is also present, for example. In an alternative embodiment, the cover cap 78 is not present at all, and the bearing plate assembly 36 only has the sensor system 76, which is connected to the bearing plate 38.

[0059] Figure 6 shows a modification of the variant of the bearing plate assembly 36 shown in Figure 5. Here, too, the two driven components 66, 90 are present, which have the respective gears 64, 88, which are driven by the gear 62 attached to the shaft 44. However, the bearing plate 38 no longer has the additional bearing seat 72. Instead, a pin / axle 92 is now held in a rotationally fixed manner by means of the bearing plate 38, which is pressed into a corresponding hole in the bearing plate 38. In other words, a press fit is created between the pin / axle 92 and the bearing plate 38. The pins / axles 92 are also held in a rotationally fixed manner on the bearing plate 38. Each gear 64, 88 is connected to one of the pins / axles 92 by means of the correspondingly adapted additional bearing 70 and is thus rotatably mounted.

[0060] Figure 7 shows a schematically simplified version of a further embodiment of the bearing shield assembly 36, wherein the two driven components 66, 90 are also present. The gears 64, 88 assigned to the driven components 66, 90 are mounted on the journals / axles 92 via the additional bearings 70 (not shown in detail). The entire bearing shield 38 is covered by the cover cap 78 made of plastic. For this purpose, the edge of the opening in the cover cap 78 has an undercut 94, by means of which the bearing shield 38 is encompassed on the circumference, as shown in a partial sectional view in Figure 8. In other words, the cover cap 78 and the bearing shield 38 are locked together. The passages 52 for the phase connections 35 are also covered by the cover cap 78.In this embodiment, the cover cap 78 is used solely for transporting the bearing shield assembly 36, and is removed for assembly onto other components of the electric motor 22. The cover cap 78 thus protects the sensor system 76 during transport, preventing foreign particles from penetrating it. Thus, cleaning the sensor system 36 after transport and / or during assembly is not necessary.

[0061] A further embodiment of the bearing plate assembly 36 is shown in a perspective view in Figure 9 and in a top view in Figure 10. The sensor system 76 is still present and essentially corresponds to the embodiment shown in Figure 5. The cover cap 78, by means of which the sensor system 76 is covered, is adapted accordingly. In this embodiment, the cover cap 78 has a plurality of fastening tabs 96 that project outwards and are each riveted to the bearing plate 38 using a rivet 98. For this purpose, the rivets 98, which run parallel to the axis of rotation 28, are each guided through a corresponding rivet opening 100 of each fastening tab 96. Each passed-through end is widened using a wobble riveting process so that the cover cap 78 can no longer be detached from the bearing plate 38.

[0062] The phase terminals 35 are located in the passages 52 and are attached to the stator 34 at the end opposite the cover cap 78. A total of six such phase terminals 35 and associated passages 52 are provided.

[0063] The bearing plate 38 further comprises three mounting openings 102, which are designed as holes extending parallel to the rotational axis 28 and through the bearing plate 38. A mounting element 104 is located in each of these mounting openings 102, which is attached to the stator 34 shown in Figure 11 and extends parallel to the rotational axis 28.

[0064] The mounting elements 104 are made of a plastic and attached to a plastic body of the switching contact unit 30. In the assembled state, the ends of the mounting elements 104, which are designed in the manner of a plastic dome and extend through the respective associated mounting opening 102, are widened using a hot-stamping process, so that the stator assembly 20, namely the switching contact unit 30, and the bearing plate assembly 26 are riveted together. In other words, the mounting elements 104 are plastic domes and serve to fasten the stator assembly 20 to the bearing plate 38. In addition, a clearance fit is formed between each mounting opening 102 and the associated mounting element 104, although these elements abut one another. As a result, the stator assembly 20 is also aligned with respect to the bearing plate 38 by means of the mounting elements 104 and the mounting openings 102. The invention is not limited to the exemplary embodiments described above.Rather, other variants of the invention can also be derived from this by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the individual embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

[0065] List of reference symbols

[0066] 2 motor vehicles

[0067] 4 wheel

[0068] 6 Body

[0069] 8 Auxiliary unit

[0070] 10 Drive unit

[0071] 12 Sensor

[0072] 14 Control unit

[0073] 16 carrier unit

[0074] 18 recording

[0075] 20 Stator assembly

[0076] 22 electric motor

[0077] 24 Stator

[0078] 28 Rotation axis

[0079] 30 switching contact unit

[0080] 35 phase connection

[0081] 36 End shield assembly

[0082] 38 Bearing shield

[0083] 40 bearing seat

[0084] 42 warehouses

[0085] 44 Wave

[0086] 46 Rotor

[0087] 48 second camp

[0088] 49 second warehouse location

[0089] 50 wraparound

[0090] 52 passage

[0091] 54 tab

[0092] 56 Opening

[0093] 58 Fastening element

[0094] 60 screw receptacle

[0095] 62 gear

[0096] 64 additional gear driven component additional shaft additional bearing additional bearing seat additional rotation axis sensor cover cap holder sealing element collar screw additional gear additional driven component pin undercut fastening tab rivet rivet opening assembly opening assembly element

Claims

Claims 1. End shield assembly (36) of an electric motor (22), comprising a bearing shield (38) having a bearing seat (40) in which a bearing (42) is held, wherein a cover cap (78) is fastened to the bearing shield (38).

2. Bearing plate assembly (36) according to claim 1, characterized in that the cover cap (78) is detachably connected to the bearing plate (38).

3. Bearing plate assembly (36) according to claim 1 or 2, characterized in that the bearing plate (36) has a receptacle (82) by means of which a sealing element (82) is held, via which the cover cap (78) rests against the bearing plate (38).

4. End shield assembly (36) according to one of claims 1 to 3, characterized in that a passage (52) for a phase connection (35) is covered by means of the cover cap (78).

5. Bearing shield assembly (36) according to one of claims 1 to 4, characterized in that the bearing (42) is covered by means of the cover cap (78).

6. Bearing shield assembly (36) according to one of claims 1 to 5, characterized in that a sensor system (76) for determining a position of a shaft (44) mounted by means of the bearing (42) is connected to the bearing shield (38), the sensor system (76) being covered by means of the cover cap (78).

7. Bearing shield assembly (36) according to claim 6, characterized in that the sensor system (76) has a component (66) driven by means of the shaft (44) which is rotatably mounted by means of the bearing plate (38).

8. End shield assembly (36) according to one of claims 1 to 7, characterized in that the end shield (38) has a mounting opening (102) for receiving a mounting element (104) for fastening and / or aligning a stator assembly (20).

9. End shield assembly (36) according to one of claims 1 to 8, characterized in that a tab (54) projecting in a radial direction is connected to the end shield (38), which tab comprises an opening (56) for receiving a fastening element (58) for fastening to a carrier unit (16).

10. Electric motor (22) with a bearing plate assembly (36) according to one of claims 1 to 9, by means of which a housing (24) is closed.

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