DE102017203261A1 - Method for producing an electrical machine - Google Patents

Abstract

The invention relates to a method (68) for producing an electrical machine (26) of a motor vehicle (4), in particular a steering motor. A housing (30) with a stator (50) is provided, and a rotor (48) is inserted into the housing (30). An end shield (36) having a bearing (38) for rotatably supporting the rotor (48) is placed on the housing (30) and a variable (78) characterizing the position of the rotor (48) with respect to the stator (50) is determined , The bearing plate (36) is displaced relative to the housing (30) such that a deviation (82) between a nominal value (84) and the characteristic quantity (78) is less than or equal to a limit value (92), and the bearing plate (36). is attached to the housing (30). The invention further relates to a device (54) for producing an electrical machine (26) of a motor vehicle (4), and an electric machine (26) of a motor vehicle (4).

Description

The invention relates to a method for producing an electrical machine of a motor vehicle and to an apparatus for producing an electrical machine of a motor vehicle and an electrical machine of a motor vehicle. The electric machine is preferably a steering motor.

Motor vehicles have a plurality of adjusting drives, each comprising an electric motor, by means of which an adjusting member is moved. In order to simplify a steering movement in the motor vehicle, for example, a power steering is used. In this case, an electric motor (steering motor) usually engages on a steering line rotating in a steering, by means of which a toothed rack is moved transversely. The rack in turn is coupled to the wheels to be moved in the steering of the motor vehicle. In an alternative, the electric motor acts directly on the rack and spends it in the transverse direction. In addition, an unwanted steering angle is avoided by means of the electric motor with suitable control, for example when driving through a pothole, for which the angular movement of the steering wheel of the motor vehicle is monitored.

The electric motor must apply a relatively large torque, so that the steering is working properly even when the vehicle is at a standstill; so the torque is at least 3Nm and usually over 6 Nm. It is thus necessary that the individual components of the electric motor are adapted to the respective torque. The electric motor itself has a rotor which is rotatably supported by means of a bearing. The storage takes place by means of two ball bearings, which are connected to separate end shields. So that the comparatively large forces can be applied, and thus wear is low, manufacturing tolerances of the individual components must be chosen to be comparatively small. Also, a uniform force is ensured on the steering line in this way. Due to the low manufacturing tolerances, however, manufacturing costs are increased.

The invention has for its object to provide a particularly suitable method for producing an electrical machine of a motor vehicle, in particular a steering motor, and a particularly suitable apparatus for producing an electrical machine of a motor vehicle and a particularly suitable electrical machine of a motor vehicle, in particular reduced manufacturing costs and preferably a quality is increased.

With regard to the method, this object is achieved by the features of claim 1, with respect to the device by the features of claim 9 and with respect to the electrical machine by the features of claim 10 according to the invention. Advantageous developments and refinements are the subject of the dependent claims.

The method is used to produce an electrical machine of a motor vehicle. The electric machine is for example a generator. Preferably, the electric machine is an electric motor and suitably a component of an auxiliary unit, such as an adjusting drive. The adjusting drive comprises an adjusting part which is moved along an adjustment path by means of the electric motor. In a suitable embodiment of the invention, the adjusting drive is a power steering, and the adjustment is in particular either a steering arm, by means of which a rack is spent, or the rack itself, wherein by means of the rack at least one wheel of the motor vehicle pivots about a substantially vertical axis becomes. In other words, the electric machine is a steering motor.

In a further alternative, the auxiliary unit is a pump, such as a lubricant pump, in particular a transmission oil or engine oil pump. In a further alternative, the adjustment drive is a water pump, an air conditioning compressor or a blower unit, such as a radiator fan or a heater blower (HVAC). The electric motor is, for example, a brushed commutator motor. Particularly preferably, however, the electric motor is designed brushless and preferably a brushless DC motor (BLDC). The electric machine is suitably a synchronous machine.

The method provides that in a first step, a housing is provided with a stator. The housing is expediently made of an aluminum, and, for example, in a die-casting or deep-drawing process, in particular a so-called. Cold extrusion, manufactured. Suitably, the housing is designed at least partially hollow cylindrical. The stator is preferably at least partially disposed within the housing. For example, the stator has a permanent magnet. Preferably, the stator comprises a number of electrical coils, which are connected together at least to form an electrical winding. Suitably, the stator comprises three such electrical windings which are electrically offset 120 degrees from one another. In other words, the stator is constructed in three phases. The electric coils are applied, for example, to an inner wall of the hollow cylindrical housing and are preferably attached thereto. In In other alternatives, the stator comprises redundant windings and / or has six-phase or twelve-phase design.

In a further step, a rotor is inserted into the housing. The rotor comprises, for example, an electrical coil, in particular a number of electrical coils. In the assembled state, an electromagnet is expediently provided by means of this. Particularly preferably, however, the rotor comprises a permanent magnet, expediently a number of permanent magnets. These are suitably connected to a laminated core of the rotor or embedded in this. The laminated core is designed, for example, substantially cylindrical. The rotor preferably comprises a shaft, on which the possible laminated core is placed and expediently attached thereto. At least, however, the magnets are rotatably mounted on the shaft. The rotor is arranged such that it is at least partially disposed within the housing, and thus at least partially surrounded by the housing circumferentially.

For example, the housing or a component connected to the housing has a bearing into which the rotor is introduced, in particular in this case the shaft of the rotor is introduced into this bearing. Alternatively, the bearing is fixed to the shaft before insertion into the housing and the bearing is positioned, for example, upon insertion of the rotor into the housing in a receptacle of the housing or a component connected thereto, and for example attached thereto. The rotor is introduced in particular through an opening of the housing in this, wherein the opening is expediently located on an end face of the housing. Suitably projects after insertion of the rotor on a front side, expediently on both end sides of the housing out of this and is thus on this over.

In a further step, a bearing plate with a bearing for rotatably supporting the rotor is placed on the housing. The end shield is made for example of a metal, in particular an aluminum, so pure aluminum or an aluminum alloy. Preferably, the end shield is made of the same material as the housing. For example, the bearing plate prior to placement on the rotor on the bearing, through which after placement on the housing, the rotor, in particular the shaft of the rotor, at least partially protrudes. The bearing serves for the rotatable mounting of the rotor and is expediently connected after placing the bearing plate on the housing both on the rotor, in particular the shaft, and the bearing plate. Conveniently, the bearing is each rotatably attached to the bearing plate and the shaft. By means of the end shield, the opening of the housing is expediently at least partially, preferably completely, closed, through which the rotor has been introduced into the housing. Suitably, the housing is closed by means of the bearing plate, and / or the bearing plate is preferably placed blunt on the housing. In particular, the housing does not engage positively and / or non-positively in corresponding recesses or connecting elements of the bearing plate or vice versa. However, at least the bearing plate is displaceable with respect to the housing, expediently in a tangential and radial direction with respect to the rotor, in particular the possible shaft of the rotor (rotor shaft). The mounting of the bearing plate on the housing, for example, after insertion of the rotor in the housing or simultaneously with this. In this case, the rotor is advantageously already connected before insertion into the housing with the bearing of the bearing plate.

In a further step, a variable is determined which characterizes the position of the rotor with respect to the stator. For example, for this purpose, the position of the rotor is determined with respect to the stator and used as a characteristic size. In an alternative to this, a size is determined by means of which the position of the rotor with respect to the stator can be derived, wherein the position itself is not determined directly. The size is detected, for example, and in particular measured.

In a further step, the bearing plate is moved with respect to the rotor. For example, the bearing plate is displaced with respect to the housing in a radial and / or tangential direction, these directions being expediently defined by means of the rotor. In a further alternative, the end shield is displaced in an axial direction with respect to the housing. Due to the displacement, the position of the rotor is changed with respect to the stator, since the rotor is attached to the bearing of the end shield, or at least whose position is determined by means of the bearing. The stator, however, is preferably connected to the housing. As a result, the position of the rotor with respect to the stator is changed due to the displacement of the bearing plate relative to the housing. For example, the bearing plate and / or the housing has a stop, by means of which a possible displacement is limited, so that the bearing plate with respect to the housing can be moved only within certain limits. The shift is such that a deviation between a target value and the characteristic quantity is less than or equal to a limit value. The desired value is expediently predetermined, and created or corresponds, for example, on the basis of design specifications a specific requirement for the electrical machine. Due to the shift thus the deviation between the characteristic size and the desired value is smaller than a limit value, the limit value, for example, is fixed. The limit value corresponds in particular to a predetermined error tolerance. Thus, the position of the rotor with respect to the stator deviates from a desired position only by a certain amount corresponding to the deviation. The deviation itself is suitably determined to be unsigned. In other words, the deviation is an absolute amount. If the deviation is 0 (zero), the position of the rotor with respect to the stator suitably corresponds to a desired position. The limit itself, for example, is 0 (zero). If the characteristic quantity already deviates from the setpoint value by less than the limit value, for example, no shifting operation is carried out.

In an alternative, the determination of the position of the rotor with respect to the stator characteristic size is done in one step with the placement of the bearing plate on the housing. Suitably, the touchdown is carried out such that the deviation between the desired value and the characteristic size is less than or equal to the limit value. In other words, the landing and determining operation also includes shifting the bearing shield relative to the housing such that the deviation between the desired value and the characteristic magnitude is less than or equal to the limit. This is done in particular by means of suitable manufacturing devices. In other words, the bearing plate is geometrically aligned by means of the appropriate manufacturing device to the housing. Thus, no further alignment is required, and the end shield is preferably axiert with respect to the housing.

In a further step, the bearing plate is attached to the housing. For example, fasteners are used for this purpose. Because of the attachment a displacement of the bearing plate with respect to the housing is no longer possible. Due to the method, the position of the rotor with respect to the stator is within a manufacturing tolerance that is predetermined. In this case, the housing, the bearing plate, the rotor and / or the stator can be manufactured with comparatively large manufacturing tolerances, and the alignment is effected by means of the displacement and the determination of the deviation. In this way, the manufacturing tolerances of the components can be compensated, wherein the electrical machine corresponds to a desired requirement profile. Also, the manufacturing tolerance of the entire electrical machine can be chosen lower than a manufacturing tolerance that would result from the individual components. Thus, the electric machine substantially conforms to specifications, and manufacturing tolerances are reduced. Therefore, the quality of the electric machine is increased, and manufacturing costs are reduced. In addition, in this way, a committee is reduced because it is ensured even before attachment of the bearing plate to the housing, that the characteristic size deviates from the target value by less than the limit.

For example, it is determined based on the characteristic size, in which direction and / or by what amount the bearing plate is moved with respect to the housing. In other words, after determining the characteristic quantity, only a single displacement operation is performed, and subsequently the end shield is attached to the housing. For example, after moving the bearing plate with respect to the housing, the characteristic size is determined again and thus verified that the deviation is less than or equal to the limit. Alternatively, this is ensured by means of calculation. In an alternative, a number of shift operations are performed, with the shift operations set, for example, in advance, and thus each shift operation corresponds to a particular shift direction and to a predetermined shift travel length. For example, the lengths of the shift operations are always the same, but the direction is changed. After each shift, the characterizing size is preferably determined again. In other words, each shift operation and the original state are each assigned a characteristic size. In this way, it is possible to find a minimum of the characteristic size, for which a minimization algorithm is used, for example. In other words, the characteristic quantity is iteratively determined. Due to the number of displacement operations, it is easier to determine the position of the bearing plate relative to the housing, in which the characteristic size deviates from the nominal value by at most the limit value.

The limit value used is preferably the deviation between the nominal value and the characteristic value of that of all shifting operations, which is minimal. In other words, the characteristic size is determined after each shift operation, as well as the characteristic size that exists before the first shift operation. From this number of characteristic quantities, the characteristic quantity which has the smallest deviation from the desired value is determined. This deviation is used as limit value. Following this, the bearing plate is moved again with respect to the housing and indeed to the position of the bearing plate with respect to the housing, in which just that to this Deviation corresponding characteristic size was present. Thus, the deviation between the target value and the characteristic quantity at this position is equal to the limit value. In this position, the bearing plate is attached to the housing. Thus, the electric machine has the minimum possible or at least a minimum deviation from the desired value, which is why the manufacturing tolerances in the electric machine are comparatively low.

It is suitably carried out a number of shift operations, so at least two shift operations. Preferably, the number of relocations is less than ten relocations or eight relocations. Conveniently, the number of relocations is between two relocations and five relocations, and suitably three relocations or four relocations. In this way, it is possible to determine the change in the characteristic size in the displacement operations and thus essentially heuristically determine the desired position of the bearing plate with respect to the housing, in which the deviation between the characteristic size and the desired value is less than or equal to the limit , For example, a theoretical minimum of the deviation or a heuristically found minimum of the deviation is determined on the basis of these displacement processes. Due to the comparatively small number of displacement processes, a production time is not excessively prolonged.

Suitably, the bearing plate is fastened by means of fastening means to the housing. In particular, an adhesive, clips or screws is used as fastening means. The fastening means are chosen such that the bearing plate can be fixed in different positions with respect to the housing. Particularly preferably, however, the bearing plate is materially connected to the housing. Conveniently, the bearing plate is welded to the housing. In this way, the bearing plate in a variety of positions with respect to the housing can be attached to this. Conveniently, the bearing plate is secured by laser welding to the housing. In particular, in this case there is a use of additional material, such as solder or the like, or a use of additional material is omitted.

Conveniently, the housing is sealed gas-tight by means of the bearing plate. For this purpose, preferably a laser welding connection is used. Due to the gas-tight connection between the bearing plate and the housing intrusion of foreign particles is prevented, which increases reliability of the electrical machine.

Preferably, the bearing plate is moved with respect to the housing so that the characteristic size corresponds exactly to the desired value. Thus, the position of the rotor with respect to the stator corresponds to an exact specification. For example, a concentricity of the rotor with the stator is used as the characteristic variable. In this case, an axis of the stator and an axis of the rotor are initially determined, these each representing in particular an axis of symmetry. Suitably, the stator is rotationally symmetric with respect to the associated axis and / or the rotor is rotationally symmetrical with respect to the axis associated with the rotor. For example, the center of gravity of the rotor or of the stator lies on the respectively assigned axis. The characteristic variable used here is the deviation of the two axes from each other.

For example, a minimum distance of the two axes is used as a characteristic size, wherein the distance is determined, for example, only within the housing. Alternatively, an angle of the two axes is used as a characteristic size. In particular, in this case, the limit value is a certain angle or a certain distance of the two axes from each other. Upon a displacement of the bearing plate with respect to the rotor thus the position or orientation of the two axes is changed to each other and in this way also the characteristic size.

Alternatively, a cogging torque of the rotor is used as the characteristic variable. To determine the cogging torque, for example, the rotor is rotated by a certain amount, wherein the rotatable mounting is at least partially realized by means of the bearing of the bearing plate. The cogging torque here refers in particular to a force or a torque which must be expended in order to rotate the rotor by a specific amount or even by an amount. Alternatively, the rotor is rotated / rotated by one complete revolution, ie 360 degrees, and the maximum torque is detected. This is used, for example, as a cogging torque of the rotor. Alternatively, a variance of the forces occurring here or a maximum deviation from a mean value is used. The cogging torque of the rotor is determined due to an interaction of the rotor with the stator. Depending on the position in which the rotor is located to the stator, the cogging torque varies, so that based on the cogging torque, the position of the rotor relative to the stator can be determined. Appropriately, the displacement of the bearing plate relative to the housing takes place in such a way that the cogging torque is minimal.

Alternatively, a characteristic force acting on the rotor is selected as the characteristic variable. In particular, the force is exerted by the stator on the rotor. For example, in this case the stator is energized. Suitably, in this case the force is directed in a radial direction with respect to the rotor. Particularly preferably, the characteristic size includes the concentricity of the rotor with the stator and the cogging torque of the rotor. Alternatively, the characteristic quantity includes the concentricity of the rotor with the stator and the force acting on the rotor. In a further alternative, the characteristic quantity comprises the cogging torque of the rotor and the force acting on the rotor. Particularly preferably, the characteristic variable includes the concentricity of the rotor with the stator, the cogging torque of the rotor and the force acting on the rotor. In this case, the limit expediently in each case comprises a lower limit value assigned to the respective constituent of the characteristic quantity, so that the concentricity of the rotor with the stator with a first lower limit value and the cogging torque of the rotor with a second lower limit value and / or the force acting on the rotor with a third lower limit value is compared and in each case a separate deviation is created.

For example, the concentricity of the rotor is optically determined. Alternatively, this is determined indirectly, for example, due to a force which is caused by means of any permanent magnets of the rotor on the stator or due to permanent magnets of the stator to the rotor. For example, the cogging torque is determined directly by, for example, mechanically rotating the rotor. Alternatively, the cogging torque is determined indirectly, in particular by determining an electromotive force, in particular a counter electromotive force (counter EMF).

Suitably, the characteristic quantity comprises a disturbance variable, that is to say in particular a variable which should be minimal during operation of the electrical machine and which, for example, exerts an influence on the operation of the electrical machine. In particular, in this case the electromotive force is detected, which is used as an indication of the cogging torque of the rotor. Alternatively or in combination, the force is detected, which is caused by any permanent magnets of the rotor. This is used as an indication for a Deachsierung of the rotor with respect to the stator, so to determine the concentricity of the rotor.

Appropriately, a pot-shaped housing is used. Thus, the rotor is inserted into the pot-shaped housing, wherein the possible shaft of the rotor is suitably guided through a pot bottom of the cup-shaped housing and thus protrudes through the bottom. In this way, the housing is closed by placing the bearing plate, and penetration of foreign particles into the housing is relatively effectively prevented. Also, a stability of the housing is increased. Alternatively or particularly preferably in combination with this, an A-side end shield is used as the end shield. In other words, the end shield is placed on the side of the electric machine on the housing on which a powered by the electric machine or a driving the electric machine component of the motor vehicle is arranged. Thus, the rotor is aligned by means of displacement of the bearing plate with respect to the housing on the side on which relatively large forces act. In this way wear is reduced and quality is increased.

The device for producing an electrical machine of a motor vehicle comprises a holding device for a housing of the electrical machine, for example a claw or a clamping tool. Furthermore, the device comprises a displacement device for a bearing plate with respect to the housing. The displacement device is also used, for example, the placement of the bearing plate on the housing. By means of the displacement device, it is possible to move the bearing plate relative to the housing. For example, the displacement device is a robot arm. In addition, the device comprises a tool for fastening the bearing plate to the housing, for example a welding device, in particular a laser welding device. Particularly preferably, the device comprises a detection device, in particular a measuring device, by means of which a characteristic size can be determined. The kenzeichnende size here indicates the position of a rotor of the electric machine with respect to a stator of the electric machine. The device is suitable, in particular provided and set up, to be operated in accordance with a method in which initially the housing is provided with the stator. This takes place for example by means of receiving the housing in the holding device. Further, the rotor is inserted into the housing, which is done for example by means of a suitable tool. In a further step, the bearing plate is set with a bearing for rotatably supporting the rotor on the housing, for which, for example, the displacement device is used. In a further step, the position of the rotor with respect to the stator characterizing size is determined, for which in particular the detection device is used. In a further step, the bearing plate is moved with respect to the housing such that a deviation between a desired value and the characteristic size is less than or equal to a limit. In a further step, the bearing plate is fastened to the housing, for which purpose in particular the tool for fastening the bearing plate to the housing is used. Preferably, the device comprises a control unit by means of which the method is carried out. For this purpose, the control device is preferably suitable, in particular provided and furnished.

The electric machine is part of a motor vehicle and in particular a component of an auxiliary unit of the motor vehicle, such as an adjusting drive. In particular, the electric machine is a component of a pump, such as a lubricant pump, in particular an engine oil or transmission oil pump. Alternatively, the electric machine is a component of a water pump, an air conditioning compressor or a fan heater (HVAC). In an alternative to this, the electric machine is a component of an electric window lifter, an electromotive seat adjustment, an electric motor operated tailgate or an electric sunroof. In a further alternative, the electric machine is part of a massage device of a vehicle seat. Particularly preferably, the electric machine is an electric motor, for example a synchronous motor. For example, the electric motor is a brushed commutator motor. However, the electric motor is particularly preferably designed brushless, in particular as a brushless DC motor (BLDC). Particularly preferably, the electric machine is a steering motor us thus a part of a steering device of the motor vehicle. In this case, a steering rod is moved as adjustment in particular by means of the electric motor.

The electric machine is manufactured according to a method in which first a housing is provided with a stator. A rotor is inserted into the housing, and a bearing plate with a bearing for rotatably supporting the rotor is placed on the housing. In the assembled state in this case the bearing is attached both to the bearing plate and to the rotor. In particular, the bearing is attached after mounting the end shield on the housing both on the rotor and on the housing. In a further step, a variable characterizing the position of the rotor relative to the stator is determined, and the end plate is displaced relative to the housing such that a deviation between a desired value and the characteristic quantity is less than or equal to a limit value. For this purpose, the characteristic size is determined again in particular after a successful shift operation. Subsequently, the end shield is attached to the housing.

The invention further relates to an adjustment drive of a motor vehicle with such an electric machine. The adjusting drive in this case has an adjusting part which is driven by means of the electric machine. The adjustment part is, for example, a steering column, a rack coupled to the long strand of a power steering, a pump, such as a lubricant pump, for example a transmission or engine oil pump, or a water pump. Alternatively, the adjustment is an air conditioning compressor, a heater fan, an electromotive seat adjustment or an electromotive Fensterherber.

The refinements, refinements and advantages mentioned with regard to the method, the device and / or the adjusting drive are analogously also to be transferred to the electric machine and vice versa.

• 1 eine Servolenkung eines Kraftfahrzeugs, mit einem Elektromotor,
• 2 einen Längsschnitts des ein Lagerschild aufweisenden Elektromotors,
• 3, 4 jeweils perspektivisch den Elektromotor,
• 5 schematisch eine Vorrichtung zur Herstellung des Elektromotors, und
• 6 ein Verfahren zur Herstellung des Elektromotors.

The invention will be explained in more detail with reference to a drawing. Show:

• 1 a power steering system of a motor vehicle, with an electric motor,
• 2 a longitudinal section of the bearing plate having an electric motor,
• 3 . 4 each perspectively the electric motor,
• 5 schematically a device for producing the electric motor, and
• 6 a method for producing the electric motor.

Corresponding parts are provided in all figures with the same reference numerals

In 1 is schematically simplified an adjustment 2 of a motor vehicle 4 shown in the form of a power steering. The car 4 includes a steering wheel 6 that by means of a handlebar 8th with a rack 10 over a pinion 12 is coupled. The handlebar 12 is in turn with two front wheels 14 coupled, at a steering angle of the steering wheel 6 each about a substantially perpendicular axis 16 to be pivoted. The handlebar 8th is divided into two parts, the two parts by means of a torsion bar 18 connected to each other. The between the torsion bar 18 and the steering wheel 6 located part of the handlebar 8th is a first sensor 20 and between the pinion 12 and the torsion bar 18 located part of the handlebar 8th is associated with a second sensor 22, the signaling technology with a control unit 24 are connected.

The between the pinion 12 and the torsion bar 18 located part of the handlebar 8th is also an electrical machine 26 in the form of an electric motor assigned by means of control unit 24 is controlled. This is an angular offset between the two parts of the handlebar 8th by means of the two sensors 20 . 22 recorded and thus a desired steering angle of the front wheels 14 determined. If this is present, the electric motor 26 energized so that the rotational movement of the handlebar 8th is supported.

In 2 is in a longitudinal section along a rotation axis 28 the electric motor 26 and in 3 and in 4 each shown in perspective. The electric motor has a cup-shaped housing 30 with a molded thereon B-side end shield 32 on, on which a first ball bearing 34 centrally connected. The pot-shaped housing 30 with the attached B-side end shield 32 is on the remaining side by means of an A-side end shield 36 closed, a second ball bearing 38 is. The pot-shaped housing 30 and the A-side end shield 36 are made of aluminum in a die casting or deep drawing process or by cold extrusion.

By means of the two bearings 34 . 38 is a wave 40 rotatable about the axis of rotation 28 stored. On the side of the A-side end shield 36 is the electric motor 26 by means of a transmission not shown with the handlebar 8th connected. This is the wave 40 externally toothed designed end, and the gearbox is at least partially in a by means of the A-side end shield 36 formed and from the housing 30 directed trough 41 held. In an alternative, the connection is made by means of other output geometries, such as a press association. On the side of the B-side end shield 32 is by means of the housing 30 a via the B-side end shield 36 protruding collar 42 educated. Inside the collar 42 formed space 44 are an unillustrated rotary encoder and a control electronics of the electric motor 26 positioned.

At the wave 40 is between the two camps 34 . 38 a laminated core 46 tethered, being inside recesses of the laminated core 46 a number of permanent magnets are positioned. In an alternative, the permanent magnets are on the laminated core 46 applied (surface magnets). The laminated core 46 as well as the permanent magnets as well as the shaft 40 are components of a rotor 48 , The laminated core 46 is from one to the inner wall of the housing 30 Tailored stator 50 surrounded by a number of electric coils 52 includes, by means of the electronics of the electric motor 26 in response to control commands of the control unit 24 be energized.

In 5 is a device 54 for the production of the electric machine 26 of the motor vehicle 4 shown. The device 54 has a holding device 56 for the housing 30 on. The holding device 56 is a clamping tool. Furthermore, the device comprises 54 a displacement device 58 for the end shield 36 with respect to the housing 30 , The shifting device 58 is a robotic arm. In addition, the device includes 54 a tool 60 for fixing the bearing plate 36 to the housing 30 in the form of a laser welding machine. In addition, the device includes 54 a measuring device 62 , eg in the form of a camera or a torque sensor, as well as an insertion tool 64 , Also includes the device 54 a control unit 66 in the form of a microcomputer. By means of the control unit 66 becomes an in 6 illustrated method 68 carried out that of the production of the electric machine 26 of the motor vehicle 4 serves.

In a first step 70 of the procedure 68 becomes the case 30 with the stator 50 provided. Before the first work step 70 is the stator by another method 50 inside the case 30 placed and tied to the inner wall. In addition, the first ball bearing 34 on the B-side end shield 32 been connected, which is integral with the housing 30 is, which is thus cup-shaped. The housing 30 was before insertion of the stator 50 in the case 30 made of aluminum in a die-casting process. In a second step 72 becomes the rotor 48 in the case 30 introduced. To introduce the rotor 48 this is the insertion tool 64 used. The rotor 48 becomes parallel to the axis of rotation 28 moved into the housing 30 until the laminated core 46 on the circumference of the electric coils 52 is surrounded. Here is the wave 40 through the first ball bearing 34 led them into the room 44 protrudes.

In a third step 74 becomes the A-side end shield 36 that the second ball bearing 38 has, on the housing 30 placed. For this purpose, the displacement device 58 used, which has a gripper, by means of which the A-side end shield 36 is seized. The wave 40 gets into the second ball bearing 38 threaded and on the shaft 40 attached. The A-side end shield 36 becomes dull and only loose on the front of the case 30 attached, the B-side end shield 32 and the room 44 opposite. The hollow 41 Here is the case 30 away. The second and third work steps can be carried out simultaneously in a variant, so that the rotor in the housing 30 is introduced, at the same time the A-side end shield 36 on the case 30 is set. Here is the wave 40 already attached to the second ball bearing 38. In summary, in the third step 74 the rotor 30 with the A-side end shield 36 loosely put together.

In a fourth step 76 is by means of the measuring device 62 one the position of the rotor 48 with respect to the stator 50 distinctive size 78 certainly. As a characteristic size 78 becomes the concentricity of the rotor 48 with the stator 50 used. For this purpose, first the axis of symmetry of the rotor 48 determines the axis of rotation 28 equivalent. Further, the axis of symmetry of the rotor 50 determined by the arrangement of the electric coils 52 as well as the design of the housing 30 is predetermined due to fault tolerances. Alternatively or in combination with this, a cogging torque of the rotor 48 determined as well as one on the rotor 48 Acting force. For this purpose, another, unspecified tool accesses the rotor 48 and turns it with respect to the stator within the two bearings 34 . 38 , Further, by means of the tool on the rotor 48 acting force determined if at least one of the electric coils 52 powered by the electronics, not shown. In this case, a magnetic force acts between the permanent magnets of the rotor 48 and by means of the electric coil 52 formed electromagnet. Furthermore, the electromotive force (EMF) is determined in the energization of the electric coils 52 occurs. The characteristic size 78 this includes both the concentricity of the rotor 48 with the stator 50 , the cogging torque of the rotor 48 as well as the on the rotor 48 acting force as well as the electromotive force (EMF) and is thus a vector.

In a fifth step 80 will be a deviation 82 between a setpoint 84 and the characteristic size 78 certainly. The setpoint 84 is also a vector, and the deviation 82 is unsigned and, for example, also a vector or a number. In a subsequent fifth step 86 is by means of the displacement device 58 the A-side end shield 36 with respect to the housing 30 postponed. Here, the A-side end shield 36 substantially perpendicular to the axis of rotation 28 spent. Due to the displacement of the A-side end shield 36 with respect to the housing 30 will also be the wave 40 that by means of the second camp 38 is held, with respect to the housing 30 and thus with respect to the housing 30 connected stator 50 emotional. Thus, the distance between the laminated core changes 46 and the electric coils 52 ,

After the sixth step 86 in turn becomes the fourth step 76 and the fifth step 80 performed, with the A-side end shield 36 with respect to the housing 30 is spent in a further position, which has not yet from the A-side end shield 36 was taken. In other words, it becomes a move operation 88 the A-side end shield 36 with respect to the housing 30 performed, and after each move 88 becomes again the characteristic size 78 and therefore again the concentricity, the cogging torque and the acting force are determined. There will be either three or four shift operations 88 carried out. After completion of the last move 88 becomes in the fifth step 80 minimal deviation 82 certainly. In addition, the position of the rotor 48 relative to the stator 50 at which this (minimum) characteristic size 78 was determined. In a subsequent seventh step 90 becomes the A-side end shield 36 in the position relative to the housing 30 spent at the characteristic size 78 was determined by the setpoint 84 the slightest deviation 82 having. This deviation 82 is considered a limit 92 used. In other words, in the seventh step 90 the A-side end shield 36 with respect to the housing 30 shifted so that the deviation 82 between the setpoint 84 and the characteristic size 78 less than or equal to the limit 92 is.

In a subsequent eighth step, the A-side bearing plate 36 by means of the tool 60 for fixing the A-side end shield 36 on the housing 30 attached. For this purpose, the A-side end shield 36 with the housing 30 laser welded, so that a cohesive connection between the A-side end shield 36 and the housing 30 results. Alternatively, the A-side end shield 36 by means of a further welding process, for example electron beam welding, to the housing 30 attached. Thus, a weld 96 between the A-side end shield 36 and the housing 30 created.

The connection is gas-tight, so that the penetration of foreign particles into the housing in the region of the abutting edges of the A-side end shield 36 with the housing 30 is prevented.

In summary, the made of an aluminum and in particular made of aluminum combination of housing 30 and the A-side end shield 36 connected by a laser welding process. Here, the alignment of the parts to each other, and thus the concentric orientation of the stator 50 to the rotor 48 by means of the device 54 and in particular by means of the displacement device 58 and the holding device 56 produced. Furthermore, in the alignment process of the housing 30 with respect to the A-side end shield 36 carried out a measurement of disturbances, the disturbance, for example, the cogging torque of the engine 26 is. In this way, the housing 30 and the A-side end shield 36 specifically aimed at a minimum just the disturbance to each other.

Due to the orientation of the A-side end shield 36 and the housing 30 with the contraption 54 with which also the rotor 48 in the case 30 is introduced, it is not necessary that at the junction between the housing 30 and the A-side end shield 36 special requirements for component tolerances must be made. In this way, the production of the A-side end shield 36 as well as the housing 30 less expensive in the production. A further reduction in manufacturing costs is due to the elimination of material for connection between the A-side end shield 36 and the housing 30 realized. In other words, no additional connecting elements, such as mounting ears or press fits are needed. Due to the interference torque optimized production, so the setting of the cogging torque of the rotor 48 as well as the concentricity and the acting force, it allows that much of the components of the electric machine 26 can be manufactured with comparatively large component tolerances, which leads to a further reduction in manufacturing costs. The required accuracy is still due to the displacement of the A-side end shield 36 with respect to the housing 30 in particular due to the fourth, fifth, sixth and especially the seventh working step 76 . 80 . 86 . 90 reached. The characteristic size 78 is comparatively easy and inexpensive to measure, so the process 68 can be performed in a relatively short period of time.

Due to the weld 96 No sealing elements are required, which further reduces manufacturing costs. In addition, a weight and a size is reduced because no space must be provided for such a sealing element. In addition, no sealing points must be processed. Due to the reduced length, in addition to the installation space and the weight, an improved connection and a stiffer overall structure is realized, which improves acoustics, and essentially all component manufacturing tolerances can be compensated, which is why they can be set comparatively high.

The invention is not limited to the embodiment described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all the 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 NUMBERS

2

adjustment

4

motor vehicle

6

steering wheel

8th

handlebars

10

rack

12

pinion

14

front

16

axis

18

torsion bar

20

first sensor

22

second sensor

24

control unit

26

electric machine

28

axis of rotation

30

casing

32

B-side end shield

34

first ball bearing

36

A-side end shield

38

second ball bearing

40

wave

41

trough

42

collar

44

room

46

laminated core

48

rotor

50

stator

52

electric coil

54

contraption

56

holder

58

Shifter

60

Tool for attaching the bearing plate to the housing

62

measuring device

64

insertion tool

66

control unit

68

method

70

first step

72

second step

74

third step

76

fourth step

78

distinctive size

80

fifth step

82

deviation

84

setpoint

86

sixth step

88

move operation

90

seventh step

92

limit

94

eighth step

96

Weld

Claims (10)

Method (68) for producing an electrical machine (26) of a motor vehicle (4), in particular a steering motor, in which a housing (30) with a stator (50) is provided, a rotor (48) is introduced into the housing (30), - a bearing plate (36) with a bearing (38) for rotatably supporting the rotor (48) is placed on the housing (30), determining a variable (78) characterizing the position of the rotor (48) with respect to the stator (50), - The bearing plate (36) relative to the housing (30) is displaced such that a deviation (82) between a desired value (84) and the characteristic size (78) is less than or equal to a limit value (92), and - The end plate (36) is attached to the housing (30). Method (68) according to Claim 1 characterized in that a number of shift operations (88) are performed, and after each shift operation (88), the characterizing quantity (78) is redetermined. Method (68) according to Claim 2 , characterized in that the limit value (92) used is the deviation (82) between the setpoint value 84) and the characteristic quantity (78) of that of all the shifting operations (88) which is minimal. Method (68) according to Claim 2 or 3 , characterized in that three or four shift operations (88) are selected. Method (68) according to one of Claims 1 to 4 , characterized in that the bearing plate (36) and the housing (30) are welded, in particular laser welded. Method (68) according to one of Claims 1 to 5 , characterized in that the housing (30) by means of the bearing plate (36) is sealed gas-tight. Method (68) according to one of Claims 1 to 6 , characterized in that as a characteristic quantity (78) a concentricity of the rotor (48) with the stator (50), a cogging torque of the rotor (48) and / or a force acting on the rotor (48) are selected. Method (68) according to one of Claims 1 to 7 , characterized in that a pot-shaped housing (30) and / or an A-side end plate (36) are selected. Device (54) for producing an electrical machine (26) of a motor vehicle (4), comprising a holding device (56) for a housing (30) and a displacing device (58) for a bearing plate (36) with respect to the housing (30), as well a tool (60) for attaching the bearing plate (36) to the housing (30), and according to a method (68) according to one of Claims 1 to 8th is operated. Electric machine (26) of a motor vehicle (4), in particular steering motor, which according to a method (68) according to one of Claims 1 to 8th is made.

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