ELECTRIC MOTOR

Description

[0001] The invention relates to an electric motor of a motor vehicle and a method for assembling an electric motor, as well as an auxiliary unit of a motor vehicle with an electric motor. The electric motor has a stator, a rotor, a switching unit, and a contact adapter.

[0002] Motor vehicles, such as passenger cars, have a multitude of auxiliary units that do not directly serve to propel the vehicle. Such auxiliary units are required, for example, for the operation of the main drive or serve to provide or increase comfort for the vehicle user. One such auxiliary unit is, for example, an electric motor-driven adjustment drive, such as an electric motor-driven window lifter. Alternatively, the auxiliary unit is, for example, an electric motor-driven refrigerant compressor, which is in particular a component of a refrigerant circuit of the motor vehicle.

[0003] In a further alternative, the electric motor is a component of the motor vehicle's braking system. In this case, the electric motor is, for example, a component of an anti-lock braking system, an anti-skid control system, or an electric motor-operated brake force distribution system. However, it is also possible to use the electric motor in a brake force generator. In this case, the electric motor, in particular, drives a hydraulic pump, thereby increasing the pressure in a brake fluid system. The electric motor is actuated using electrical signals, and the brake force generator is mechanically controlled by a foot pedal or other input devices. The electric motor can therefore be operated independently of any actuation or other inputs from a user. Consequently, it is possible to brake the motor vehicle using the brake force generator, even if this is no longer possible for the user in an emergency situation.

[0004] To keep wear and tear as low as possible, electric motors are usually designed as brushless direct current (BLDC) motors. The electric motor has a rotor containing multiple permanent magnets that are non-rotatably attached to a rotor shaft. The rotor shaft is mounted to rotate about a rotor axis by one or more bearings, with each bearing attached to a respective bearing shield. The stator has multiple electrical coils that are electrically connected to three phases of a stator winding by means of a switching unit, also known as an interconnection ring, that is mounted on the stator. The individual phase connections are offset by 120° with respect to the rotor axis, and a connection that is led through an opening in the bearing shield is usually electrically connected to these connections.

[0005] US 2020 / 195083 A1 discloses an electric motor with a busbar unit comprising a plurality of busbars. The busbars are each electrically connected to coils and inserted on one end plate side of the busbar unit through a plurality of connection through-holes in the end plate.

[0006] DE 10 2019 200 616 A1 shows a stator with a stator base body having stator teeth for accommodating an electrical winding. The stator base body is inserted into a cylindrical housing having a bearing shield at one end. The electrical winding is connected to a connection plate for power supply, and several axial extensions are arranged on the connection plate, by means of which connection pins are guided through axial openings in the bearing shield.

[0007] From US 2018 / 316239 A1 a motor is known which comprises a rotor with a shaft and a stator which is arranged so as to be opposite to the rotor in a radial direction.

[0008] DE 10 2019 202 859 A1 shows an electric machine. A signal sensor is arranged on a bearing plate. The signal sensor is attached to the inner side of the bearing plate opposite a rotor and is arranged axially directly opposite a signal generator.

[0009] A stator is known from DE 10 2017 205 532 A1. An insulation mask is arranged on a winding support, which insulates an electrical coil from the winding support. The insulation mask extends axially beyond a yoke element with an axial extension, wherein the axial extension rests radially against an inner wall of a pole housing with a circumferentially extending collar.

[0010] DE 10 2015 200 086 A1 discloses a wiring board for a stator of an electrical machine. The wiring board has conductor elements that, on the one hand, comprise axial connection plugs for connecting plugs and, on the other hand, fastening sections whose ends have a flattened—in particular, approximately rectangular—cross section, wherein the ends contactingly enclose a round connecting wire of a winding.

[0011] The invention is based on the object of specifying a particularly suitable electric motor of a motor vehicle and a particularly suitable method for assembling an electric motor as well as a particularly suitable auxiliary unit of a motor vehicle, wherein waste is advantageously reduced and / or assembly is simplified.

[0012] With regard to the electric motor, this object is achieved according to the invention by the features of claim 1, with regard to the method by the features of claim 9, and with regard to the auxiliary unit by the features of claim 10. Advantageous further developments and refinements are the subject of the respective subclaims.

[0013] The electric motor is a component of a motor vehicle. The electric motor is suitable, in particular provided and configured, for this purpose. In other words, in the intended state, the electric motor is mounted on other components of the motor vehicle. The electric motor is suitable, in particular provided and configured, for this purpose. The motor vehicle is in particular land-based and preferably has multiple lanes. In this case, it is suitably possible to position the motor vehicle essentially freely, for example on a corresponding roadway. For this purpose, the motor vehicle in particular 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.

[0014] For example, the electric motor is a component of a main drive of the motor vehicle and thus serves to (directly) propel the motor vehicle. However, the electric motor is particularly preferably a component of an auxiliary unit of the motor vehicle. In its intended use, the auxiliary unit does not directly propel the motor vehicle and therefore does not constitute the main drive of the motor vehicle. The electric motor therefore preferably has a nominal or maximum output of between 100 W and 1000 W, preferably between 300 W and 700 W and, for example, between 400 W and 500 W. For example, the auxiliary unit serves to operate the main drive or to provide functions required for the operation of the motor vehicle that do not directly serve to propel the motor vehicle. Alternatively, the auxiliary unit can be used to increase comfort or to provide comfort functions.

[0015] The auxiliary unit is, for example, an electric motor-driven adjustment drive, such as an electric window lift. Alternatively, the auxiliary unit is, for example, an electric motor-driven refrigerant compressor, which is particularly a component of a motor vehicle's refrigerant circuit. InIn another alternative, the auxiliary unit is an electric motor pump, such as a water pump. Suitably, the electric motor pump is a lubricant pump, such as an engine oil pump or a transmission oil pump. In this case, the electric motor drives, for example, a pump wheel that is adapted to the fluid to be pumped. In another alternative, the electric motor is a component of a fan, such as a radiator fan or a blower, which thus constitutes the respective auxiliary unit. In another alternative, the auxiliary unit is a steering assistance system, and in particular a steering rod is driven by the electric motor, or at least a steering angle of steerable wheels of the motor vehicle is adjusted by means of the electric motor, or their adjustment is assisted.

[0016] In a further alternative, the auxiliary unit is a braking system or part of the braking system of the motor vehicle. In this case, the electric motor is, for example, a component of an anti-lock braking system, an anti-skid control system, or an electric motor-operated brake force distribution system. The auxiliary unit is particularly preferably a braking force generator. This is preferably designed electrohydraulically, with the electric motor in particular operating a hydraulic pump and / or actuating any valves. Alternatively, a working piston is moved by means of the electric motor. The working piston is in particular arranged in a pump chamber in which brake fluid is present during operation. When the working piston moves linearly in the pump chamber, the brake fluid is pushed out of the pump chamber or sucked in, depending on the direction of movement.Preferably, any brake pistons of brakes of a braking system of the motor vehicle are hydraulically connected to the pump chamber so that the brakes are actuated when the brake fluid is pressed out of the pump chamber.

[0017] For example, an input rod is attached to the working piston, which is expediently provided with a thread on its circumference, at least in sections, onto which an internally toothed drive gear is mounted. A type of spindle is formed by the input rod and the drive gear. The drive gear is expediently driven by the electric motor, for example, directly or preferably via a gearbox. When the electric motor is energized, power is thus transmitted via the drive gear to the input rod and consequently also to the working piston.

[0018] The brake force generator preferably comprises a sensor by means of which, during operation, actuation of a foot pedal acting as a brake pedal is detected. The electric motor is energized depending on this. There is no mechanical connection between the foot pedal and the working piston, and the foot pedal is not, for example, a component of the brake force generator. Suitably, the brake force generator comprises a control unit by means of which the sensor is read and the energization of the electric motor is adjusted. In a further development, the electric motor is energized by means of the control unit independently of an actual actuation of the foot pedal, preferably depending on a provided request, which is transmitted in particular via a possible bus system. The request is generated, for example, by an assistance system of the motor vehicle or an on-board computer of the motor vehicle.In particular, the prompt is generated depending on specific driving situations, for example, by an emergency braking assistant. Alternatively, or in combination with this, the vehicle is designed to be partially or fully autonomous, allowing it to move independently of user control. The prompt is generated, in particular, by a so-called autopilot.

[0019] In another alternative, the brake vehicle is designed as an electromechanical brake booster. For example, the input rod is connected to the foot pedal by means of a mechanism so that it is adjusted directly when the foot pedal is actuated. In this case, the electric motor serves in particular to support the movement of the foot pedal during normal operation, which is why the force required by a user is reduced. Alternatively, or in combination with this, the force to be applied can be adjusted so that it is always constant, regardless of the current driving situation. However, it is also preferably possible here to move the working piston independently of the foot pedal being actuated, namely by supplying the electric motor with appropriate current. This also broadens the field of application here.

[0020] In particular, the electric motor is designed as a brushless direct current (BLDC) motor and / or synchronous motor. The electric motor has a stator and a rotor, which are arranged concentrically to a motor axis in a motor housing. The motor housing is closed by a bearing plate arranged perpendicular to the motor axis. For example, the rotor comprises a laminated core into which permanent magnets are embedded or on which they are held. Suitably, the rotor comprises a rotor shaft, which is preferably arranged along the motor axis, also referred to as the rotor axis. The rotor shaft, or at least the rotor, is suitably rotatably mounted by means of one or more bearings, with at least one of the bearings expediently being connected to the bearing plate.In this case, part of the rotor shaft protrudes beyond the bearing shield, so that this part is located outside the motor housing, or the rotor shaft is not, for example, a component of the rotor. If the other bearing is present, it is preferably assigned to a different bearing shield, so that the motor housing is closed on both sides by one of the bearing shields. In other words, the motor housing is at least partially hollow-cylindrical. Alternatively, the motor housing is pot-shaped, and one of the bearings is attached to a pot base of the motor housing, which thus takes on the function of one of the bearing shields. With such a motor housing, tightness is increased and assembly can be carried out in a shorter time. Alignment is also simplified. Since the rotor and stator are located in the motor housing, they are protected from environmental influences by the motor housing and the bearing shield, thus increasing robustness.For this purpose, the motor housing closed with the bearing shield is preferably designed to be fluid-tight.

[0021] For example, the stator surrounds the rotor circumferentially, so that the electric motor is designed as an internal rotor. Suitably, the stator is at least partially hollow-cylindrical. The stator has a stator winding. Preferably, the stator winding comprises a plurality of electrical coils, which are preferably made of an enamel wire, for example an enamel aluminum wire or enamel copper wire. Preferably, two of the electrical coils are formed by a common wire and thus connected by a wire section, so that the respective two electrical coils are electrically connected in series. In particular, the stator has between six such electrical coils and twenty electrical coils, and suitably twelve electrical coils. Expediently, each of the electrical coils, which is also referred to simply as a coil, is wound on a respective associated stator tooth.The stator teeth are preferably formed by a common stator core. An electromagnet is formed by the electrical coils, or the respective electromagnet at least additionally comprises the respective stator tooth. In summary, several electromagnets are formed, at least in part, by the stator winding.

[0022] The electric motor further comprises a switching unit that is electrically contacted with the stator winding. For example, the switching unit is welded or soldered to the stator winding. Alternatively, the switching unit has, for example, a hook or the like into which at least part of the enameled wire forming the stator winding is inserted. The individual electrical coils of the stator winding are preferably connected by means of the switching unit. The electrical coils are preferably connected to form several phases, with the same number of electrical coils suitably assigned to each of the (electrical) phases. In this case, when one of the phases is energized during operation, all electrical coils of this phase are energized. In particular, the electrical coils of the same phase are electrically connected in parallel or in series.For example, the stator comprises two such phases, and the electric motor is thus two-phase, or preferably three such phases, so that the electric motor is three-phase. The phases themselves are connected to each other, for example, to form a delta or star connection. In other words, the stator winding is thus configured in the manner of a delta or star connection.

[0023] To connect the individual electrical coils, the switching unit expediently has one or more separate busbars, which, in the assembled state, are in particular in contact with corresponding ends of the respective electrical coil. In this case, these busbars, for example, merely rest against one another or are fastened to one another, preferably by welding or brazing. The individual busbars of the switching unit are suitably held on a body of the switching unit, which is preferably made of a plastic. In this way, an electrical short circuit between the individual busbars is avoided.

[0024] The switching unit is mounted on the stator. As a result, the switching unit is also located within the motor housing and is thus protected by it. The switching unit is located in particular at one end of the stator. Preferably, the switching unit is mounted on an end face of the stator and is thus offset from the stator along the motor axis. Expediently, the switching unit, preferably any body, lies mechanically directly against the stator, thus increasing stability and robustness. The switching unit is suitably arranged congruent with the stator, thus reducing the space required. Preferably, the switching unit is ring-shaped and / or arranged perpendicular to the motor axis, which further reduces the space required. Expediently, the switching unit is attached to the stator, for example by means of adhesive, clips, or screws. Alternatively, it can be attached by clamping.In another alternative, the switching unit simply rests loosely on the stator.

[0025] The electric motor further comprises a contact adapter for an electrical motor connection. In other words, the contact adapter is suitable, expediently provided, and configured to be electrically contacted with the motor connection so that the electric motor can be energized via the motor connection. In other words, the contact adapter serves to accommodate the electrical motor connection and to make electrical contact therewith. For example, the (electrical) motor connection is a component of any control system, in particular of any auxiliary unit, or the motor connection is a component of the electric motor, in particular of the electronics of the electric motor. Particularly preferably, an electrical bridge circuit is electrically contacted with the motor connection.

[0026] The contact adapter is connected to the switching unit and is thus stabilized by it. In other words, the contact adapter is held by the switching unit, in particular preventing it from becoming detached. The position of the contact adapter is thus at least partially specified by the switching unit. For example, the contact adapter is attached to the switching unit. Furthermore, the contact adapter is electrically contacted to the switching unit and preferably to the stator winding by means of the switching unit. The contact adapter particularly preferably comprises one or more plug contacts, wherein each of the possible phases of the stator winding is suitably assigned at least one of the plug contacts and thus electrically contacted.

[0027] The contact adapter further comprises a plug connection, which expediently has any plug contacts. The plug connection serves in particular for the mechanical connection to the motor connection. The plug connection is preferably designed accordingly for this purpose. The plug connection is arranged in an opening in the bearing plate, so that its position is predetermined by the opening in the bearing plate. For example, a gap is formed between the edge of the opening and the plug connection, or they lie against one another in a force-fitting manner, so that fluid-tightness is ensured despite the opening. Alternatively, a seal is arranged between them, for example. In particular, the plug connection, in particular any plug contacts, are arranged parallel to the motor axis.

[0028] Due to the arrangement of the plug connection in the opening of the bearing plate, electrical contact with the stator winding is possible even after the bearing plate has been attached to the motor housing, allowing the electric motor to be at least partially prefabricated. This simplifies production. Due to the arrangement of the plug connection parallel to the motor axis, the motor connection can be made using a movement parallel to the motor axis, which means that contacting via the motor housing is not hindered. This further simplifies the assembly of the electric motor.

[0029] Furthermore, the opening allows the position of the plug connection to be specified relatively precisely, so that electrical contact with the motor connection, which may be a component of an electronics system and / or arranged on a circuit board, is always made, regardless of the manufacturing tolerances selected when creating the electric motor. It is only necessary to select small manufacturing tolerances when opening the bearing shield, thus reducing manufacturing costs and simplifying production. This also reduces waste. Furthermore, it is possible to use the electric motor in different applications or with different manufacturers of motor connections. In this case, only the contact adapter needs to be replaced. Otherwise, identical parts can be used, thus reducing manufacturing costs.

[0030] In particular, the plug connection is electrically contacted with each of the possible electrical phases of the stator winding. In this way, it is possible to design the bearing plate to be closed, with the exception of the opening and a further opening for the possible rotor shaft, so that tightness and robustness are increased. Furthermore, the electrical contact is simplified and it is possible, for example, to arrange any electronics that have the motor connection offset with respect to the motor axis, which means that the required installation space is reduced. Particularly preferably, the plug connection is offset with respect to the motor axis and is, for example, not arranged symmetrically with respect to a radial straight line with respect to the motor axis. In this way, the utilization of the available space is further improved.

[0031] For example, the stator or preferably the switching unit has a means for alignment within the motor housing during assembly. This ensures that the contact adapter connected to the switching unit is actually arranged within the opening, thus further reducing rejects. For example, the stator or particularly preferably the switching unit has a hole or other opening arranged parallel to the motor axis but offset therefrom, which serves to temporarily accommodate a tool by means of which positioning takes place. For this purpose, the tool preferably has a corresponding mandrel or the like for insertion into the hole so that the switching unit and thus also the stator are aligned. In this case, the tool, suitably the mandrel, expediently lies in the hole of the switching unit or stator by means of a clearance fit.This allows for comparatively precise positioning while reducing the amount of force required. Furthermore, damage to the switching unit or stator is avoided due to the reduced force applied.

[0032] The tool preferably has a further mandrel or the like that interacts with corresponding receptacles in the motor housing, in particular any holes, such as mounting holes, provided for receiving screws or the like for fastening the motor housing to a driven component. In summary, the tool thus engages both the motor housing and the switching unit or stator, and these are consequently aligned accordingly, which simplifies assembly.

[0033] The plug connection is mounted in a floating manner on the switching unit. In other words, at least slight movement of the plug connection relative to the switching unit is possible, while it is nevertheless connected to the switching unit, preferably by means of additional components of the contact adapter, and electrically contacted with it. Due to the floating mounting, tolerance compensation is possible, so that the plug connection can always be arranged in the opening, while still allowing a comparatively small width of a slot between the plug connection and the edge of the opening.

[0034] For example, the switching unit is designed to be smooth in the area of ​​the plug connection. In this way, the movement of the plug connection is not impeded due to the floating mounting by means of the switching unit. Manufacturing is also simplified. However, the switching unit particularly preferably comprises a recess within which the plug connection is arranged with play. The recess determines the extent to which the plug connection is mounted in a floating manner. In other words, the recess limits the adjustment path in the floating mounting, which makes assembly robust and therefore easier. In other words, the recess serves to at least provisionally position the plug connection and ensures that twisting of the plug connection with respect to an axis running parallel to the motor axis is prevented or at least limited.This simplifies the insertion of the connector into the opening of the bearing plate during assembly. In summary, the recess ensures that twisting or tilting of the connector is prevented or at least reduced to a manageable level.

[0035] Alternatively or in combination with this, the plug connection has a pin which runs parallel to the motor axis and which lies with play within a hole in the switching unit. The hole thus specifies the movement of the pin and thus also the movement of the plug connection relative to the switching unit. The pin also prevents or at least limits tilting of the plug connection. The pin, which is designed like a pin, is expediently conical at its free end so that insertion into the hole is simplified during assembly. The hole can be continuous or, for example, designed like a blind hole. At the very least, however, the hole also runs parallel to the motor axis, which on the one hand simplifies production. On the other hand, it makes it easier to arrange the pin in the hole.

[0036] For example, the plug connection is attached to the switching unit by means of a cable or the like. Alternatively, the plug connection is attached directly to the switching unit, or electrical contact is made via a sliding contact, for example. In this way, a comparatively comprehensive floating bearing is also possible. However, the contact adapter particularly preferably comprises a contact arm that is connected to the plug connection. For example, the contact arm or at least a part thereof is molded onto the plug connection and thus at least partially integral with part of the plug connection. In this way, robustness is increased and assembly is simplified. The contact arm is arranged in particular perpendicular to the motor axis.

[0037] The contact arm is elastically deformable and / or flexible. Furthermore, the contact arm is attached to the switching unit, particularly rigidly. As a result, the deformation of the contact arm results in the floating mounting of the plug connection, while the plug connection is still securely connected to the switching unit via the contact arm. In particular, a region of the contact arm spaced apart from the plug connection is attached to the switching unit, thus improving the floating mounting.

[0038] The contact arm particularly has a curved, for example, circular-arc-shaped, adapter section arranged between the connection to the switching unit and the connection to the plug connection. Preferably, the center of the circular arc is on the motor axis, so that available space is utilized comparatively efficiently and assembly is simplified.

[0039] The contact adapter preferably has a plurality of such contact arms, so that stability is increased. Suitably, the plug connection comprises the plug contacts, wherein one of the plug contacts is expediently assigned to each of the contact arms. Particularly preferably, each contact arm has an electrically conductive region which in particular electrically contacts the respective plug contact and is, for example, connected to it. Particularly preferably, each contact arm also comprises electrical insulation, by means of which the respective electrically conductive region is at least partially surrounded and which is provided, for example, by means of a plastic overmolding. Preferably, the electrical insulation of the respective contact arm is integrally formed with a housing of the plug connection, by means of which the plug contacts are held. In this way, assembly of the motor connection is simplified.This also prevents an electrical short circuit of the connector contacts via the bearing plate. The connector contacts are designed, in particular, like male connectors. The motor connector preferably has corresponding sockets, within which the respective connector contact is at least partially inserted and electrically connected when assembled.

[0040] Preferably, the contact adapter is electrically contacted with the switching unit. For this purpose, the contact adapter expediently has a connection lug located at the end of the contact arm facing away from the plug connection. This is expediently contacted by brazing with a corresponding connection element of the switching unit. In this way, robustness is increased, while the effort required to establish the electrical contact is reduced. Alternatively, the connection element and the connection lug are welded together. In a further alternative, the connection lug and the connection element are inserted into one another, so that no further aids are required to establish the electrical contact.The connection lug is suitably created by means of the electrically conductive region / part of the contact arm, in particular a busbar, and the connection lug is preferably arranged outside the insulation and expediently forms the only part of the electrically conductive region / part of the contact arm that is arranged outside the respective insulation. The connection element of the switching unit is formed, for example, by means of a part of the stator winding, which, for example, protrudes through the possible body of the switching unit and is thus also assigned to it. However, the connection element is preferably formed by means of at least a part of one of the possible busbars, so that robustness is increased. Thus, mechanical stabilization of the plug connection via the contact arm by means of the connection element is also achieved, so that robustness is increased, while the number of required components is reduced.

[0041] For example, the opening is designed to be comparatively large, so that even with large manufacturing tolerances, positioning of the plug connection within the opening is always possible. However, the contact adapter particularly preferably has means for positioning the plug connection in the opening. In other words, the means serve to position and preferably align the plug connection in the opening. Due to the means, it is therefore also possible to select comparatively large manufacturing tolerances for the individual components of the electric motor, while still ensuring that the plug connection is positioned within the opening. In this case, only comparatively small manufacturing tolerances need to be provided for the means.

[0042] It is advisable for the plug connection to be mounted in a floating manner and / or for the contact arm to be present. InIn this case, for example, the contact arm(s) may be deformed during assembly due to the means used, but the connection of the contact adapter to the switching unit is not damaged. Conveniently, the electrical contact is also retained.

[0043] For example, the means comprise a pin or the like that engages with or locks into a corresponding contour of the bearing plate. However, the means particularly preferably comprise crimp ribs that are formed on the outside of the plug connection and run parallel to the motor axis. These are also positioned within the opening, with the plug connection being aligned in the opening by means of the crimp ribs. For this purpose, the crimp ribs suitably rest mechanically directly on the edge of the opening. This results in, for example, partial deformation of the crimp ribs, particularly when comparatively high manufacturing tolerances prevail. The crimp ribs prevent damage to the plug connection. The crimp ribs are preferably conical or flattened at the ends, particularly at the end facing away from the switching unit.As a result, insertion into the opening is simplified, while still allowing for comparatively precise positioning of the connector terminal within the opening. In summary, the mechanical contact of the crimp ribs with the edge of the opening positions the connector terminal, which may, for example, partially deform the crimp ribs. However, at least the positioning / alignment of the connector terminal is achieved.

[0044] The crimp ribs are suitably designed such that when the plug connection is inserted into the opening parallel to the motor axis, the crimp ribs successively come into mechanical contact with the edge of the opening, at least if an exact alignment already exists. For this purpose, the crimp ribs are particularly designed such that, after insertion is complete, they have a different projection parallel to the motor axis over the edge. In other words, the crimp ribs have a different height parallel to the motor axis over the edge. Suitably, the thickness of the crimp ribs, i.e. their extension perpendicular to the motor axis, is the same or at least constant after the possible conical / flattened section.As a result, the connector terminal is first aligned in one dimension by one of the crimp ribs and then in another dimension by another crimp rib, thus preventing tilting and reducing the force required to insert the connector terminal into the opening.

[0045] For example, the contact adapter has two or more such crimp ribs. Suitably, the means have three corresponding crimp ribs. Particularly preferably, the crimp ribs are configured such that they are initially aligned in a tangential direction relative to the motor axis, then in a radial direction, and preferably subsequently in a radial and tangential direction.

[0046] Preferably, the means also comprise additional crimp ribs, some of which are configured such that they come into mechanical contact with the edge of the opening simultaneously. In other words, at least one group is formed in which the crimp ribs come into contact with the edge of the opening substantially simultaneously upon insertion, thus preventing tilting of the plug connection due to a purely unilateral application of force. However, at least one crimp rib is also present, in which mechanical contact with the edge occurs before or only after insertion.

[0047] Particularly preferably, the plug connection comprises a plug receptacle which is located on the side facing away from the switching unit and runs parallel to the motor axis. The plug receptacle, which is designed in particular in the manner of a hole or bore, serves to temporarily accommodate a positioning tool and is suitable, in particular provided and configured for this purpose. In particular, the plug receptacle is no longer used in the assembled state, i.e. after completion of the manufacture or assembly of the electric motor, and remains, for example, free. The plug receptacle is suitably arranged between any plug contacts so that any available space is used comparatively efficiently. The plug receptacle, which serves as a positioning bore, is designed, for example, to be continuous or preferably like a blind hole so that damage to the switching unit (located underneath) is avoided when the positioning tool is accommodated.

[0048] For assembly, the positioning tool is first guided through the opening in the bearing plate into the plug-in receptacle so that the plug connection is suitably aligned with the opening. The bearing plate is then moved relative to the positioning tool and the plug connection so that the plug connection is guided through the opening. The arrangement and position of the plug connection relative to the positioning tool, however, are expediently not changed. The positioning tool prevents the plug connection from catching on the edge of the opening and also from tilting the plug connection. In particular, the positioning tool is designed like a pin and is preferably conical at the free end so that insertion into the plug connection is simplified. Alternatively, or in combination with this, the plug connection is widened on the opening side.After completing the positioning of the connector terminal within the opening, the positioning tool is removed. This allows it to be reused in a subsequent assembly process. Preferably, the means for positioning the connector terminal are present, suitably the crimping ribs. In this case, the positioning tool is used, in particular, for rough positioning, with the crimping ribs providing the final positioning.

[0049] The method is used to assemble an electric motor of a motor vehicle. The electric motor comprises a stator with a stator winding and a rotor, as well as a switching unit and a contact adapter for an electrical motor connection. The stator and the rotor are arranged concentrically to a motor axis in a motor housing, which is closed by a bearing plate arranged perpendicular to the motor axis. The switching unit is placed on the stator and electrically contacted with the stator winding, with the contact adapter connected to the switching unit and electrically contacted with it. A plug connection of the contact adapter is arranged in an opening in the bearing plate.

[0050] According to the method, i.e. during or for assembling the electric motor, the switching unit is first placed onto the stator and electrically contacted with the stator winding. For this purpose, for example, the switching unit is placed onto the ends of any electrical coils, which are then inserted into corresponding receptacles in the switching unit, in particular parallel to the motor axis. The switching unit is then suitably rotated parallel to the motor axis, clamping the inserted parts of the stator winding. At least preferably, the ends of any electrical coils are moved into an area of ​​the receptacles with a reduced diameter, so that stabilization occurs. Furthermore, electrical contact is made between the switching unit and the stator winding, for which purpose, in particular, any busbars of the switching unit are welded or soldered to the ends of the electrical coils inserted into the receptacles.

[0051] In addition, the contact adapter is connected to the switching unit and electrically connected to it. The contact adapter is preferably attached to the switching unit, in particular to any contact arms. For example, the contact adapter, i.e. at least a part of it, such as the contact arms, is welded or soldered to the switching unit, suitably to a corresponding busbar of the switching unit. Each busbar is expediently assigned one of the contact arms.

[0052] In one embodiment, the switching unit is placed on the stator and electrically connected to the stator winding before the contact adapter is connected to the switching unit and electrically connected to it. In an alternative, the contact adapter is connected and electrically connected to the switching unit first, and only then is the switching unit placed on the stator and electrically connected to the stator winding.

[0053] In a subsequent work step, the stator, to which the switching unit to which the contact adapter is connected is already attached, is arranged concentrically to the motor axis in the motor housing. Suitably, the switching unit or the stator has the hole by means of which positioning takes place within the motor housing, which is in particular pot-shaped. For example, the stator is first arranged concentrically to the motor axis within the motor housing and then aligned using the tool. Preferably, however, the stator is arranged in the motor housing using the tool so that it is arranged in an aligned manner in the motor housing. In particular, the motor housing is first heated so that it expands. The stator is then arranged in an aligned manner in the expanded motor housing, which is then cooled.This shrinks the motor housing, securely holding the stator in place. Alternatively, or in combination with this, the stator is additionally secured to the motor housing using fasteners and / or an adhesive.

[0054] The motor housing is then closed with the bearing shield. The rotor is held on the bearing shield, in particular by means of the bearing fastened to the bearing shield. When the motor housing is closed with the bearing shield, the rotor is arranged concentrically to the motor axis in the motor housing, in particular with the exception of only part of the rotor shaft, if any. For closing, the bearing shield is moved towards the motor housing, in particular parallel to the motor axis, and in particular inserted into the opening in the motor housing. The plug connection is arranged in the opening in the bearing shield. The plug connection is preferably aligned when the motor housing is closed with the bearing shield or before, so that it is always arranged / positioned in the opening in the bearing shield.Particularly preferred is the use of a positioning tool, which, before the motor housing is closed using the bearing shield, is guided through the opening in the bearing shield and positioned in the plug-in receptacle. In particular, the positioning tool also holds the bearing shield, thus reducing the number of required components. After the motor housing is closed using the bearing shield, the bearing shield is expediently attached to the motor housing.

[0055] Preferably, the means for positioning the plug connection are present within the opening. When the plug connection is inserted into the opening, the contact adapter, namely the plug connection, is aligned in a first axial position relative to the bearing plate in a tangential direction with respect to the motor axis, wherein in this position the contact adapter, preferably one of the crimping ribs, touches the bearing plate. In contrast, at least one of the crimping ribs is still spaced from the edge of the opening, for example in an axial direction, i.e. in a direction parallel to the motor axis. In a second axial position relative to the bearing plate, which differs from the first axial position, the contact adapter is aligned relative to the bearing plate in the radial direction with respect to the motor axis, in particular when the contact adapter aligned in the tangential direction touches the bearing plate.In the second axial position, in particular, a further crimp rib makes mechanical contact with the edge of the opening. In a third axial position, the contact adapter, preferably the plug connection, is aligned radially and / or tangentially in the opening of the bearing plate, in particular symmetrically, preferably while resting against the bearing plate. In the third axial position, a further crimp rib suitably makes mechanical contact with the edge of the opening.

[0056] The auxiliary unit is a component of a motor vehicle, for example, a commercial vehicle such as a bus or a truck. Particularly preferably, the auxiliary unit, when assembled, is a component of a passenger car. The auxiliary unit does not directly propel the motor vehicle, but rather, for example, operates a main drive, provides comfort functions, and / or adjusts the direction of movement of the motor vehicle.

[0057] Particularly preferably, the auxiliary unit is a brake force generator. When the electric motor is operated, the brake force generator increases the pressure in a brake fluid system. The brake fluid system comprises, in particular, a pump chamber of the brake force generator, suitably a compensation chamber, and preferably a plurality of brake pistons, with at least one brake piston being assigned to each wheel of the motor vehicle. Suitably, each wheel is assigned a plurality of brake pistons, which are arranged, in particular, on a brake caliper or a brake calliper.

[0058] For example, the brake force generator is designed electromechanically and thus acts like a brake booster. In this case, a mechanical movement, which is caused in particular by a user actuating a foot pedal, is assisted by the brake force generator so that the force required by the user is reduced. For example, the assistance is provided in such a way that the force required is essentially always the same, regardless of the current state of the auxiliary unit. In an alternative, the brake force generator is designed electrohydraulically. In this case, there is no mechanical coupling to any foot pedal, and the operation of the electric motor is carried out solely on the basis of electrical signals, which are generated, for example, by a displacement sensor assigned to the foot pedal.Since there is no mechanical coupling with input devices that can be operated by the user, it is possible to operate the brake force generator independently of it, so that it can also at least partially assume the function of an anti-lock braking system, an anti-skid control system, an electronic stability control and / or an electric motor-operated brake force distribution.

[0059] At least the auxiliary unit has an electric motor, which has a stator with a stator winding and a rotor, as well as a switching unit and a contact adapter for an electrical motor connection. The stator and the rotor are arranged concentrically to a motor axis in a motor housing, which is closed by a bearing plate arranged perpendicular to the motor axis. The switching unit is placed on the stator and is electrically contacted with the stator winding, wherein the contact adapter is connected to the switching unit and is electrically contacted with it. A plug connection of the contact adapter is arranged in an opening of the bearing plate.

[0060] Furthermore, the invention relates to a motor vehicle with such an auxiliary unit.

[0061] The further developments and advantages explained in connection with the electric motor can also be transferred analogously to the process / the auxiliary unit / the motor vehicle as well as to each other and vice versa.

[0062] An embodiment of the invention is explained in more detail below with reference to a drawing. In the drawings: Fig. 1 schematically shows a motor vehicle with an electro-hydraulic brake force generator, Fig. 2 schematically shows a sectional view of the electro-hydraulic brake force generator having an electric motor, Fig. 3 an exploded view of the electric motor comprising a stator and a rotor as well as a switching unit and a contact adapter, Fig. 4 a method for assembling an electric motor, Fig. 5 during assembly of the electric motor in perspective the stator onto which the switching unit is placed, Fig. 6, 7 each in perspective the contact adapter, Fig. 8, 9 detail in perspective and in a sectional view the contact adapter connected to the switching unit, Fig. 10 perspective the stator arranged in a motor housing, Figs. 11-16 each in a sectional view the assembly of a bearing plate on the motor housing by means of a tool comprising a positioning tool, Fig.17 shows a perspective view of a plug connection of the contact adapter during assembly of the electric motor, which is arranged in an opening of the bearing plate, Fig. 18, 19 each show a perspective view of the plug connection arranged in the opening of the bearing plate, Fig. 20, 21 each show the removal of the tool from the electric motor, and Fig. 22 shows a perspective view of the assembled electric motor.

[0063] Corresponding parts are provided with the same reference numerals in all figures.

[0064] In Figure 1A motor vehicle 2 in the form of a passenger car is shown in a simplified schematic. The motor vehicle 2 has a plurality of wheels 4, by means of which contact is made with a roadway (not shown in detail). Some of the wheels 4 are driven by a main drive (not shown). For braking, the motor vehicle 2 has a plurality of brakes 6, of which only one is shown. Each of the brakes 6 comprises a brake disc 8, which is connected in a rotationally fixed manner to the respective associated wheel 4. A brake caliper 10 of the brake 6 is held fixedly on the body side and has a plurality of brake pistons (not shown in detail).

[0065] The brake pistons are part of a brake fluid system 12, which has an expansion tank 14 that is fluidically coupled to the brake pistons. Furthermore, an auxiliary unit 16 in the form of an electrohydraulic brake force generator is coupled to the expansion tank 14. The brake fluid system 12 is filled with brake fluid, and when the (electric / electromotor) auxiliary unit 16, i.e., the electrohydraulic brake force generator, is operated, the pressure in the brake fluid system 12 increases, so that the brake pistons are actuated via the expansion tank 14. As a result, brake pads attached to the brake caliper 10 are pressed against the associated brake disc 8, thereby braking the motor vehicle 2.

[0066] In Figure 2The auxiliary unit 16, i.e. the electro-hydraulic brake force generator, is shown in a sectional view along a longitudinal axis 18. This has a pump chamber 20, within which a working piston 22 is arranged and guided along the longitudinal axis 18 by means of the side wall of the pump chamber 20. The working piston 22 extends as far as the inner walls of the pump chamber 20, so that the latter is divided into two parts by the working piston 22. One of the parts is fluidly connected to the expansion tank 14 via an outlet (not shown in detail) and is completely filled with brake fluid. When the working piston 22 moves in the pump chamber 20, the quantity of brake fluid arranged therein is thus changed.

[0067] The working piston 22 is attached via a connecting rod 24, which is arranged parallel to the longitudinal axis 18, to an input rod 26, which also extends along the longitudinal axis 18 and is displaceably mounted along the longitudinal axis 18 by means of a bearing (not shown in detail). However, the input rod 26 is mounted in a rotationally fixed manner, so that rotation of the input rod 26 is avoided.

[0068] The input rod 26 has external teeth, and a drive gear 28, which in turn has internal teeth, is mounted on it. The input rod 26 and the drive gear 28 are thus designed like a spindle. Additionally, the drive gear 28 has external teeth and meshes with a gear 30. The gear 30 is driven by an electric motor 32, which is designed as a brushless direct current (BLDC) motor.

[0069] When the electric motor 32 is energized, the drive gear 28 is rotated via the transmission 30. Due to the meshing with the input rod 26, a force is applied to the input rod 26 along the longitudinal axis 18. Due to the application of force, the working piston 22 is moved in the pump chamber 20. As a result, the brake fluid is forced out of the pump chamber 20, thus actuating the brakes 6. The electric motor 32 is operated when a foot pedal (not shown in detail) is actuated by a driver, which is not mechanically coupled to the auxiliary unit 16 and is detected by a corresponding sensor. It is also possible to actuate the auxiliary unit 16, i.e., the electrohydraulic brake force generator, completely independently of the actuation of the foot pedal.Consequently, braking of the motor vehicle 2 occurs independently of the actuation of the foot pedal, for example during emergency braking or during automatic / autonomous operation of the motor vehicle 2.

[0070] The Fig. 3The electric motor 32 shown in an exploded view has a stator 34 and a rotor 36 as well as an annular switching unit 38 and a contact adapter 40. A hollow cylindrical laminated core of the rotor 36 is fixedly mounted on a motor or rotor shaft 42, which is also hollow cylindrical. A number of permanent magnets 44 are attached to the circumference of the laminated core. The stator 34 of the electronically commutated electric motor 32 carries a stator winding 46 in the form of a number of (electrical) coils 48. These are electrically connected to one another or to one another by means of the switching unit 38, for example, creating (forming) a delta or star connection. The switching unit 38 has a number of connection contacts or lugs 50, of which only one is designated here for the sake of clarity.

[0071] The electric motor 32 also has a pot-shaped motor housing 52 and a bearing plate 54. This closes the motor housing 52 when the electric motor 32 is assembled. Furthermore, the electric motor 32 in the exemplary embodiment has two bearings 56, namely ball bearings. An annular wave spring washer 58 serves to generate an adjusting or axial force on the bearing 56 on the bearing plate side. An annular washer 60 arranged on the housing base of the motor housing 52 when the electric motor 32 is assembled serves, for example, to insulate and / or dampen the stator 34 within the motor housing 52.

[0072] The contact adapter 40 has a plug connection 62 with plug contacts (male contacts) 64. Three plug contacts 64 are provided for the three-phase electric motor 32. The bearing plate 54 has an opening (plug opening) 68 that is radially offset outward relative to a motor axis 66, wherein the rotor 36 is rotatably mounted about the motor axis 68 by means of the bearings 12. When the electric motor 32 is assembled, the plug contacts 64 of the contact adapter 40 penetrate the opening 68 on the bearing plate side. The plug connection 62 of the contact adapter 40 is seated in this opening 68 on the bearing plate side.

[0073] In the assembled state, the plug contacts 64 are held by corresponding sockets of a motor connector, via which electrical contact is also established. The plug connector 62, namely the part extending through this bearing plate 64, is mechanically held by the motor connector, thus creating a stable connection between the plug connector 62 and the motor connector. When the electric motor 32 is operating, the motor connector supplies current to the contact adapter 40, which thus serves as the connection to the electrical motor connector.

[0074] In Figure 4 A method 70 for assembling the electric motor 32 is shown. In a first step 72, the Figure 5The rotor 34, shown in perspective, is hollow-cylindrical and concentric with the motor axis 66, with the switching unit 38 mounted on one end face of the rotor. For this purpose, the switching unit 38 is moved parallel to the motor axis 66, to which it is also concentric. The free ends of each of the electrical coils 48 are guided through corresponding receptacles 72 in a body 74 of the switching unit 38. The body 74 is made of a plastic, and by means of it, several busbars 76 made of copper are held.

[0075] After the switching unit 38 is placed on the stator 34, the ends of the electrical coils 48 guided through the receptacles 72 are welded or brazed to one of the busbars 76, by means of whose ends two of the connection elements 50 are formed, each of which is assigned to one of the receptacles 72. In summary, the switching unit 38 is thus placed on the stator 34 and electrically contacted with the stator winding 46, whereby the switching unit 38 is also held to the stator 34 due to the welding or brazing.

[0076] In addition, the perspective in the Figures 6 and 7The contact adapter 40 shown is connected to the switching unit 38 and electrically contacted therewith. The switching unit 40 has, as already explained, the plug connection 62 with the three plug contacts 64, which are made of copper. These are held within a housing 78 of the plug connection 62, which is made of plastic. During production, the plug contacts 64 are overmolded using the plastic. A total of three contact arms 80 are molded onto the housing 78 of the plug connection 62, namely an insulation for the respective contact arm 80, which is thus integral with the housing 78. Each contact arm 80 has a busbar surrounded by the insulation, which is electrically contacted at one end within the housing 78 with an associated plug contact 64.The remaining end is led out of the insulation to form a terminal lug 82, which thus forms the end of the respective contact arm 80 facing away from the plug connection 62. Between the terminal lug 82 and the plug connection 62, each contact arm 80 is arcuately configured, and the materials of each contact arm 80 are selected to be flexible and elastic.

[0077] For assembly, a pin 84 of the plug connection 62, which is located on the side opposite the plug contacts 64, is arranged with play in a hole 86 of the switching unit 38, which runs parallel to the motor axis 66 and is arranged within a recess 88 of the switching unit 38. The plug connection 62 is also inserted into the recess 88 with the side opposite the plug contacts 64, as shown in Figure 8shown in detail. Each terminal lug 82 is attached to one of the connection elements 50 by brazing and thus also electrically contacted. However, the contact adapter 40 is not further attached to the switching unit 38. Due to the flexible and elastic design of the contact arms, only the terminal lugs 82 of the contact adapter 40 are held stationary on the switching unit 38.

[0078] The pin 84 is, as in Figure 9shown in a sectional view parallel to the motor axis 44, arranged with play within the hole 86 of the switching unit 38, so that a gap or slot is formed between the pin 84 arranged parallel to the motor axis 44 and the edge of the hole 86 running parallel to the motor axis 44. Due to this and the edge of the recess 88, the plug connection 62 is mounted in a floating manner on the switching unit 38. By means of the recess 88 and the hole 86, the amount of the maximum movement of the plug connection 62 with respect to the switching unit 38 perpendicular to the motor axis 44 is predetermined.

[0079] In a subsequent second work step 90, the stator 34, to which the switching unit 38 is attached, to which the contact adapter 40 is connected, is arranged concentrically to the motor axis 44 in the motor housing 52, as in Figure 10 There, as in the Figures 8 and 9, further components of the electric motor 32 are already shown, but are not yet mounted at the time of the method 70, such as the bearing 12.

[0080] To arrange the stator 34 in the motor housing 52, the metal motor housing 52 is heated so that it expands. The stator 38, with the components attached to it, is then arranged concentrically to the motor axis 44 and subsequently cooled. To align the stator 34 and the switching unit 38 within the motor housing 52, a mandrel of a tool (not shown in detail) is inserted into a hole 92 in the switching unit 38 that runs parallel to the motor axis 44. The tool has one or more further mandrels, each of which is inserted into a respective fastening hole 94 in the motor housing 52. The mandrels are inserted into a flange 96 of the motor housing 52 that lies opposite the pot base along the motor axis 44.The total of four fastening holes 94 each serve to accommodate a screw (not shown) by means of which the electric motor 32 can be mounted to other components of the auxiliary unit 16.

[0081] In a third step 98, the motor housing 52 is closed with the bearing plate 54, for which a Figure 11in a section along the motor axis 44 is used. The positioning tool 100 initially holds the bearing shield 54, which is aligned perpendicular to the motor axis 44. The associated bearing 12 is already attached to the bearing shield 54. The motor shaft 42 of the rotor 36, to which the laminated core 36 and the permanent magnets 44 are attached, is also held on the bearing 12. The remaining bearing 12 is attached to the end of the rotor shaft 42 opposite the bearing shield 54. In summary, the rotor 36 is thus held on the bearing shield 54, and upon insertion into the motor housing 52, the rotor 36 is moved concentrically to the motor axis 44 along this axis into the motor housing 52, so that the rotor 36 is circumferentially surrounded by the stator 38. The motor housing 52 is held in a rotationally fixed manner within a holder 102.

[0082] The positioning tool 100 also has a mandrel 104 which is arranged within the opening 68 of the bearing plate 54. In Figure 12 The mandrel 104 is shown in a simplified schematic representation, which is arranged parallel to the motor axis 44 and is conical at the free end facing the switching unit 54. The mandrel 106 is located above, i.e. displaced in a direction parallel to the motor axis 44, the plug connection 62, which is floatingly mounted on the switching unit 38, which has the hole 86 within which the pin 84 of the plug connection 62 lies. On the side opposite the pin 84, i.e. on the side facing away from the switching unit 38, the plug connection 62 has a plug receptacle 106 which runs parallel to the motor axis 44 and is designed like a blind hole. The plug receptacle 106 is located between the plug contacts 64 and is formed solely by means of the plastic of the plug connection 62.

[0083] When the positioning tool 100 is moved in the direction of the holder 102, and thus towards the motor housing 52, the mandrel 104 plunges into the plug-in receptacle 106 at the free end, as shown in the Figures 13 and 14 shown. For this purpose, the mandrel 104 is additionally displaced parallel to the motor axis 44, for example, with respect to the other components of the positioning tool 100. Due to the conical design of the mandrel 104, immersion is possible even if the plug connection 62 is offset. Due to the floating mounting of the plug connection 62 with respect to the switching unit 38, the plug connection 62 is displaced perpendicular to the motor axis 44 and thus aligned during immersion. The bearing plate 54 is still spaced from the plug connection 62. The positioning tool 100, namely the mandrel 104, served for the rough positioning of the plug connection 62 below the opening 68.

[0084] As the positioning tool 100 approaches the holder 102 further, the bearing plate 54 comes into mechanical contact with the motor housing 52, so that the motor housing 52 is closed by the bearing plate 54 arranged perpendicular to the motor axis 44. The bearing 12, spaced apart from the bearing plate 54, thereby moves into an assembly position on the bottom of the cup-shaped motor housing 52 and is secured there by a press fit. Furthermore, the plug connection 62, which has already been roughly positioned by the positioning tool 100, enters the opening 68 of the bearing plate 54 and partially penetrates it. As a result, the plug connection 62 of the contact adapter 40 is arranged in the opening 68 of the bearing plate 54 and remains there.

[0085] When the plug connection 62 penetrates the opening 68 of the bearing plate 54, the free ends of the plug connections 64 first pass through the opening, as shown in Figure 17shown in perspective. Subsequently, the plastic part of the plug connection 62 also partially penetrates and covers the opening 68, which is arranged in the region of a step 180 of the bearing plate 54. By means of the step 108, the bearing plate 54 is divided into two different annular regions arranged concentrically to the motor axis 44, which are offset with respect to the motor axis 44, with one annular region surrounding the other.

[0086] The contact adapter 40 further comprises means 110 for positioning the plug connection 62 in the opening 68. The means 110 have a plurality of crimp ribs 112 formed on the outside of the plug connection 62 and running parallel to the motor axis 44. The crimp ribs 112 are formed on different sides of the plastic part of the plug connection 62 and each have a flattened portion 114 at the end facing the plug contacts 64, thus facilitating insertion into the opening 68. In addition, the crimp ribs 112 are designed such that when the plug connection 62 is inserted into the opening 68 parallel to the motor axis 44, parts of it successively come into mechanical contact with the edge of the opening 68.

[0087] Here, two of the crimp ribs 112 are designed in such a way that they simultaneously come into mechanical contact with the edge of the opening 68, by means of which an alignment of the plug connection 62 in the tangential direction with respect to the motor axis 44 takes place. Figure 17 These two crush ribs 112 already protrude through the opening 68. Subsequently, another of the crush ribs 112, which is in Figure 17 is already visible, and which is formed on the side of the plug connection 62 facing the motor axis 44, through the opening 68. By means of this, a radial alignment of the plug connection 62 takes place. Subsequently, two of the crimp ribs 112 come into mechanical contact with the edge of the opening 68, as in Figure 19shown. These are located on the side of the plug connection 62 facing away from the motor axis 44. By means of these crush ribs 112, both a radial and a tangential alignment of the plug connection 62 within the opening 68 is achieved. In summary, due to the crush ribs 112, the plug connection 62 is aligned differently depending on the axial position of the bearing plate 58 with respect to the motor housing 52, whereby the crush ribs 112 sometimes deform. The alignment, which is possible due to the floating bearing of the plug connection 62, is a fine positioning in which any remaining offset between the plug connection 62 and the opening 68 is compensated. In summary, by means of the crush ribs 112, a fine positioning of the plug connection 62 in the opening 68 is achieved so that the plug connection 64 is in the desired position upon completion.

[0088] During the successive insertion of the crimping ribs 112 into the opening 68, the mandrel 104 is still located within the plug-in receptacle 106, so that despite the crimping ribs 112 and the force exerted thereby on the plug connection 62, tilting of the plug connection 62 is avoided. After the bearing plate 54 rests against the motor housing 52 and is fastened thereto, as shown in the Figures 20 and 21 As shown, the positioning tool 100 and the mandrel 104 are lifted from the bearing plate 54, which remains on the motor housing 52. In other words, the mandrel 104 of the positioning tool 100 is removed from the socket 106, which consequently only serves to temporarily hold the positioning tool 100.

[0089] Following this, the creation of the electric motor 32 is completed, which is Figure 22shown in perspective. Here, the motor housing 52 is closed by means of the bearing plate 54, and the plug connection 62 of the contact adapter 40 protrudes through the opening 68, so that the motor connection can be plugged in there despite the closed motor housing 52.

[0090] The invention is not limited to the exemplary embodiment 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 exemplary embodiment can also be combined with one another in other ways without departing from the subject matter of the invention. List of reference symbols

[0091] 2 Motor vehicle 4 Wheel 6 Brake 8 Brake disc 10 Brake caliper 12 Brake fluid system 14 Expansion tank 16 Accessory unit 18 Longitudinal axis 20 Pump chamber 22 Working piston 24 Connecting rod 26 Input rod 28 Drive gear 30 Gearbox 32 Electric motor 34 Stator 36 Rotor 38 Switching unit 40 Contact adapter 42 Motor shaft 44 Permanent magnet 46 Stator winding 48 Electric coil 50 Connection element 52 Motor housing 54 Bearing shield 56 Bearing 58 Wave washer 60 Washer 62 Connector connection 64 Connector contact 66 Motor shaft 68 Opening 70 Process 72 Receptacle 74 Body 76 Busbar 78 Housing 80 Contact arm 82 Connection lug 84 Pin 86 Hole 88 Recess 90 Second step 92 Hole 94 Mounting hole 96 Flange 98 Third step 100 Positioning tool 102 Bracket 104 Mandrel 106 Receptacle 108 Step 110 Middle 112 Crimp rib 114 Flattening

Claims

1. Electric motor (32) of a motor vehicle (2), in particular an auxiliary unit (16), comprising a stator (34) having a stator winding (46) and also comprising a rotor (36) as well as comprising a switching unit (38) and comprising a contact adapter (40) for an electrical motor connection, - wherein the stator (34) and the rotor (36) - are arranged concentrically to a motor axis (44) in a motor housing (52) which is closed by an end plate (54) arranged perpendicularly to the motor axis (44), - wherein the switching unit (38) is mounted on the stator (34) and electrically contact-connected to the stator winding (46), - wherein the contact adapter (40) is attached to the switching unit (38) and electrically contact-connected to it, and - wherein a plug connection (62) of the contact adapter (40) is arranged in an opening (68) in the end plate (54), and - wherein the plug connection (62) is mounted in a floating manner on the switching unit (38).

2. Electric motor (32) according to Claim 1, characterized in that the switching unit (38) has a recess (88) within which the plug connection (62) is arranged with play.

3. Electric motor (32) according to Claim 1 or 2, characterized in that the plug connection (62) has a pin (84) which runs parallel to the motor axis (44) and is situated within a hole (86) in the switching unit (38) with play.

4. Electric motor (32) according to any of Claims 1 to 3, characterized in that a flexible and / or elastic contact arm (80) is attached to the plug connection (62) and is fastened to the switching unit (38).

5. Electric motor (32) according to Claim 4, characterized in that the contact arm (80) has a connection lug (82) at the end facing away from the plug connection (62) for contact-connection purposes, which connection lug is contact-connected to a corresponding connection element (50) of the switching unit (38) by means of brazing.

6. Electric motor (32) according to either of Claims 1 and 5, characterized in that the contact adapter (40) has means (110) for positioning the plug connection (62) in the opening (68).

7. Electric motor (32) according to Claim 6, characterized in that the means (100) comprise pinch ribs (112) which are integrally formed on the outside of the plug connection (62) and run parallel to the motor axis (44) and are formed in such a way that, when the plug connection (62) is inserted into the opening (68) parallel to the motor axis (44), they gradually come into mechanical contact with the edge of the opening (68).

8. Electric motor (32) according to Claim 6 or 7, characterized in that the plug connection (62) has, on the side facing away from the switching unit (38), a plug-in receptacle (106), which runs parallel to the motor axis (44), for temporarily receiving a positioning tool (100).

9. Method (40) for assembling an electric motor (32) according to any of Claims 1 to 8, in which - the switching unit (38) is mounted on the stator (34) and electrically contact-connected to the stator winding (46), and the contact adapter (40) is attached to the switching unit (38) and electrically contact-connected to it, wherein the plug connection (62) is mounted in a floating manner on the switching unit (38), - the stator (34) is arranged concentrically to the motor axis (44) in the motor housing (52), and - the motor housing (52) is closed by the end plate (54) on which the rotor (36) is held, wherein the rotor (36) is arranged concentrically to the motor axis (44) in the motor housing (52), and wherein the plug connection (62) is arranged in the opening (68) of the end plate (54).

10. Auxiliary unit (16) of a motor vehicle (2), in particular electrohydraulic brake force generator, comprising an electric motor (32) according to any of Claims 1 to 8.