Electric drive

Abstract

The invention relates to an electric drive (10), in particular a steering motor, of a motor vehicle (2), comprising a housing (22) having a motor compartment (30) and an electronics compartment (28). An electric motor (46) is arranged in a motor nacelle (30) having a stator (48) and a rotor (50) fastened to a shaft (38) arranged parallel to the axial direction (18). An electronics (52) for energizing the electric motor (46) is arranged in the electronics compartment (28). The motor compartment (30) and the electronics compartment (28) are separated by a bearing shield (26), to which a bearing (36) for supporting the shaft (38) is connected. A cover element (58) is arranged between the electronic device (52) and the bearing shield (26), which bears against the inner side (32) of the housing (22). The cooling body (56) is connected to the electronic device (52), which is supported on the cover element (58). The invention also relates to an auxiliary unit (8) of a motor vehicle (2).

Description

[0001] This invention relates to an electric drive for a motor vehicle and an auxiliary unit for a motor vehicle having such an electric drive. The electric drive is particularly a steering motor.

[0002] Motor vehicles, such as passenger cars, typically have a steering system by means of which the direction of travel is adjusted. Generally, the steering system includes a steering wheel located inside the vehicle and connected to the steering column. At its end is a gear that meshes with a rack, which is in turn supported on the vehicle's pivotable front wheels. Therefore, when the steering wheel is rotated, the rack moves laterally, and the steering angle of the wheels changes.

[0003] To enhance comfort, a steering motor is often provided, which supports the driver's steering movements, reducing the force required to operate the steering wheel while still achieving proper wheel alignment. To reduce weight and improve safety in accidents, steering systems without mechanical coupling between the steering wheel and the front wheels are known. In this case, sensors detect the angular position of the steering wheel or other operating elements, and based on this position, a steering motor driving the rack is actuated. This system is also known as a "steer-by-wire" system.

[0004] In both types of steering systems, the requirements for the steering motor are relatively high. Therefore, it should be designed to be relatively compact and insensitive to external vibrations. Consequently, the steering motor and the electronics that power it are typically housed in a common housing, allowing the steering motor to be assembled as a module and also replaceable. Furthermore, the electrical connections between the electronics and the motor are protected by the housing.

[0005] The drawback here is that when the electric motor is running, it may generate wear particles, or dust particles or liquids may seep into the housing on the drive side of the motor and further reach the electronic equipment, where they may deposit. Therefore, the electronic equipment may short-circuit or cause other damage to operation, leading to steering motor failure. Depending on the design of the steering system, the force required for steering may increase suddenly and be surprising to the driver, or the vehicle's controllability may be lost, or this may lead to steering errors (the wheels striking in the opposite direction when steering).

[0006] To avoid this, a cover element is typically arranged within the housing, separating the electronics from the other components of the steering motor. If the latter is made of plastic, it has a different coefficient of thermal expansion compared to the housing. Therefore, when the steering motor heats up, additional gaps may appear, allowing particles to penetrate. To avoid this, for example, the cover element is made of an elastic material and fastened to the housing. However, this makes assembly more difficult, thus increasing manufacturing costs. Alternatively, the cover element can be made of the same material as the housing and welded to it, which increases manufacturing costs and the weight of the steering motor.

[0007] The object of the present invention is to provide a particularly suitable electric drive for a motor vehicle and a particularly suitable auxiliary unit for a motor vehicle, wherein operational reliability is advantageously increased, and wherein failure rate, manufacturing cost and / or weight is advantageously reduced.

[0008] According to the invention, with respect to the electric drive, this objective is achieved by the features of claim 1, and with respect to the auxiliary unit, by the features of claim 9. Advantageous improvements and designs are the subject of the respective dependent claims.

[0009] An electric drive is a component of a motor vehicle. In other words, an electric drive is adapted, particularly provided and arranged, in an assembled state to connect to other components of the motor vehicle and / or to form the components of the motor vehicle. The motor vehicle is particularly land-connected and is preferably designed as a multi-lane vehicle. In this case, the motor vehicle can be positioned substantially freely, particularly on suitable roads. For this purpose, the motor vehicle conveniently has corresponding wheels. In short, preferably, the motor vehicle can be positioned substantially independently of other conditions on land. In other words, the motor vehicle is preferably not track-guided. Preferably, the motor vehicle is a passenger car or commercial vehicle, such as a truck or bus.

[0010] An electric drive, also known as an electric motor unit, is, for example, a component of the main drive system of a motor vehicle, thereby driving the vehicle during operation. However, it is particularly preferred that the electric drive is a component of an auxiliary unit of the motor vehicle, thus not directly driving the vehicle. In particular, the electric drive is a component of an adjusting drive, such as an electric seat adjuster or an electric window regulator. Alternatively, the electric drive is, for example, a component of a pump, such as a water pump or an oil pump. In another alternative, the electric drive is, for example, a gear actuator, with the auxiliary unit particularly consisting of gears. In yet another alternative, the electric drive is, for example, a component of an air conditioning compressor.

[0011] However, particularly preferably, the electric drive is a steering motor, thus the auxiliary unit is specifically the steering system. In this case, for example, during operation, the steering motor supports steering movements performed by the driver. In other words, the steering system is mechanically designed, wherein there is mechanical coupling between the operating device, such as the steering wheel, and the wheels, which are designed to be controllable / steering. However, particularly preferably, the steering system is configured as a so-called "steer-by-wire" system, and specifically, there is no direct mechanical operating connection between the operating device and the wheels configured to be controllable / steering. The steering motor preferably acts on the wheels of the controllable / steering design via a rack or the like. Advantageously, the steering motor has wheels that mesh with the rack, or is at least driven by the steering motor. Preferably, a sensor is associated with the steering wheel or other operating device, and this sensor is connected to the steering motor, particularly electrically and / or signalically. In this case, the connection is, for example, direct or via a control unit, by which the operation of the steering motor is performed based on signals / data provided by the sensor. At least preferably, the steering motor operates according to data and / or signals generated / provided by means of the sensor.

[0012] The steering motor itself comprises a housing having a motor compartment and an electronics compartment. Specifically, the housing is integrally designed and advantageously cylindrical, such as a hollow cylinder. The housing includes at least a hollow cylindrical portion. Suitably, the housing preferably extends axially, also referred to as the axial direction. The housing is suitably made of aluminum, particularly die-cast or cold-extruded aluminum.

[0013] An electric motor having a stator and a rotor is arranged in a motor housing. The rotor is fastened to a shaft arranged parallel to the axial direction. In this case, the shaft particularly forms at least partially part of the electric motor or another part of the electric drive. In this case, the shaft is preferably arranged at least in sections outside the motor housing. On the other hand, the electric motor is conveniently arranged entirely inside the motor housing. In particular, the electric motor is configured as an internal rotor such that the stator surrounds the rotor circumferentially. The stator preferably abuts against, or is at least fastened to, an inner side of the housing. In particular, the stator and rotor are designed as hollow cylinders and arranged concentrically with the shaft.

[0014] For example, the motor is a brushed commutator motor. However, it is particularly preferred that the motor is brushless, and advantageously a brushless direct current motor (BLDC). This reduces the losses that occur. The motor, preferably the stator, advantageously has one or more coils, by means of which, in each case, an electromagnet is at least partially formed. In particular, in this case, the coils are connected in a multiphase configuration, such as three phases. The stator preferably comprises coils. The motor suitably has one or more permanent magnets, which are, for example, components of the rotor.

[0015] The electronic equipment is arranged in an electronic equipment compartment. Specifically, the electronic equipment is entirely housed within the electronic equipment compartment and is used to power the motor. The electronic equipment is suitable for this purpose, particularly for providing and setting up. The electronic equipment is conveniently electrically connected to the motor, particularly the stator and / or any phase. The electronic equipment specifically includes multiple electrical and / or electronic components suitably fastened to a printed circuit board of the electronic equipment. In this case, the interconnection of the various components is conveniently achieved via the printed circuit board. If the motor is configured as a brushless DC motor, the electronic equipment advantageously has a bridging circuit, preferably a B6 circuit. However, at least the bridging circuit conveniently corresponds to multiple possible phases of the motor. The motor preferably comprises two-phase multiplied by three-phase, wherein the phase circuits are star or delta circuits. The bridging circuit is preferably a B12 circuit.

[0016] Connected to the electronic device is a cooling element, which is, for example, fastened to any printed circuit board. Specifically, the cooling element is in thermal contact with at least one component of the electronic device, such as a (power) semiconductor, by means of which, for example, any bridging circuit is at least partially formed. For example, the cooling element is supported on the printed circuit board by a component of the electronic device, or is in direct mechanical contact with the printed circuit board. The cooling element is, for example, made of a metal such as aluminum. During operation, the (lost) heat generated by the electronic device is carried away by the cooling element. For this purpose, a relatively large surface area is provided in particular by the cooling element, thereby improving the removal of waste heat.

[0017] The motor compartment and the electronics compartment are separated by a bearing housing. In this case, the bearing housing is conveniently a component of the housing, or at least fastened to the housing, preferably integrally molded to the housing, such that the bearing housing is attached to the rest of the housing, particularly by means of material locking. Advantageously, the bearing housing is formed together with any hollow cylindrical portion of the housing, thereby increasing robustness. Suitably, the motor compartment and the electronics compartment are substantially cup-shaped due to the bearing housing. The bearing housing is preferably oriented perpendicular to the axial direction, and the bearings for supporting the shaft are conveniently attached to the bearing housing. The bearings here are particularly roller bearings, suitably ball bearings. In particular, one end of the shaft protrudes through the bearing housing, such that the bearing housing is partially arranged within the electronics compartment. The bearing housing specifically forms what is known as a B-side bearing housing.

[0018] The cover element is arranged between the electronic devices below the bearing housing. Therefore, it is located within the electronic device compartment. The cover element abuts against the inside of the housing. For example, in this case, at least at certain temperatures, there is a force-locking relationship between the cover element and the inside of the housing, such that the cover element abuts against the inside of the housing in a force-locking manner. Specifically, the cover element is arranged perpendicular to the axial direction. Suitablely, the cover element is flat. Specifically, the bearing housing and / or electronic devices are covered by the cover element, thus separating them from each other. Therefore, the cover element is suitable for separating the electronic devices from the bearing housing, particularly as protection against particles, liquids, and / or dust. For this purpose, the cover element is suitable, preferably provided and installed. For example, the cover element has no unclosed notches, other openings, etc. Closure is achieved, for example, by a separate sealing element.

[0019] Preferably, multiple wires pass through the cover element, making it possible to energize the motor via the electronic device. In this case, the conduits suitably include any phase connectors of the motor, or at least make electrical contact with them. In this case, for example, several sealing elements exist in the channel area connecting the possible conduits through the cover element. Suitably, the cover element has a flat base made of plastic. In particular, the base is formed as a plastic body. Due to the plastic, weight and manufacturing costs are reduced. The conduits preferably pass through the base, for example, with several openings present. For example, the base is made of a single material. In this case, the sealing of the openings is achieved particularly by sealing elements fastened to the base. However, the base is particularly preferably made of different plastic components, especially manufactured by the 2K process. For example, the sealing elements are produced by plastic injection molding, thereby creating the base. The sealing elements are, for example, elastic and preferably made of elastomer or rubber. During the manufacture of the electric drive, the sealing elements used to establish an electrical connection between the electronic device and the motor are preferably pierced by any conduits.

[0020] A cooling body connected to the electronic device is supported on the cover element. Therefore, the position of the cover element is stabilized by the cooling body in at least one direction, and in particular, movement of the cover element toward the electronic device is prevented in this manner. Advantageously, the cover element is supported in the axial direction by means of the cooling body, such that axial movement of the cover element is suppressed by the cooling body. Thus, the cooling body acts as a clamping device for the cover element.

[0021] A cover element abutting the inside of the housing prevents particles and / or liquids from the motor from reaching the electronic equipment through the bearing housing. Therefore, the requirements for the bearing are relatively low, particularly as it does not need to be designed to be sealed, which reduces friction and lowers manufacturing costs. Furthermore, there are no requirements for gaps in the bearing housing, especially where any phase joints or other conduits pass through it.

[0022] Because the cover element is in direct contact with the inner side of the housing, a relatively high seal is achieved. If, during heating of the electric drive, the housing and cover element expand differently, causing the cover element to separate slightly from the inner side, the cover element is no longer completely stabilized by the housing. However, the position of the cover element is at least partially predetermined by the cooling body, resulting in a reduced sealing effect even in this case. Complete separation of the cover element is at least prevented, allowing it to continue to be used substantially unchanged after the electric drive cools down again. In summary, the support provided by the cooling body ensures that the cover element always remains in the same position, even if, for example, any force locking between the inner side of the housing and the cover element is insufficient to stabilize the position of the cover element and / or no longer exists due to current operation.

[0023] Therefore, a relatively high level of sealing is achieved through the cover element, preventing foreign particles from passing through the electronic equipment. This reduces the failure rate of the power drive and improves operational safety. To stabilize the cover element, a component that already exists or can be used in other ways—a coolant—is used, thus not increasing manufacturing costs or weight. Furthermore, it is not necessary to design the cover element to be relatively robust and / or have the same coefficient of thermal expansion as the housing, which also reduces manufacturing costs. In addition, the assembly requirements for the cover element are relatively low.

[0024] For example, the inner side of the housing is smooth. However, it is particularly preferred that the inner side has a circumferential protrusion, which protrudes inward, particularly in the radial direction. In this case, the radial direction is perpendicular to the axial direction and is advantageously determined based on a shaft or at least one axis of rotation of the shaft. The protrusion conveniently forms a component of the housing and / or is integrally molded onto a possible hollow cylindrical portion, preferably formed together with that portion. In particular, the protrusion forms at least a local reduction in the inner diameter of the housing. Thus, the housing has at least two different inner diameters, wherein the transition between the two inner diameters occurs in the region of the protrusion. In this case, the protrusion is, for example, annular. In other words, the inner diameter of the housing is the same in the axial direction on both sides of the protrusion. Alternatively, the protrusion is formed by a step or edge. In this case, the electronics compartment preferably has only two different inner diameters, wherein one reduced inner diameter advantageously extends in the axial direction from the bearing shroud to the end of the protrusion.

[0025] The cover element is advantageously located on the protrusion / and on the side away from the electronic device. For assembly, in particular, the cover element is inserted into the electronic device compartment from the end of the housing opposite the bearing shroud until the latter abuts against the protrusion, which simplifies assembly. After manufacturing, the cover element is stabilized by the protrusion and the cooling body, and the cover element is particularly located at least segmented between them. In this case, the cover element appropriately and mechanically abuts directly against the protrusion and the cooling body. Therefore, the position of the cover element in the axial direction is predetermined by the cooling body and the protrusion. For example, in this case, the cover element is fastened to the protrusion and / or the cooling body, for example, by adhesive. However, it is advantageous that no additional fastening is required, and the stabilization of the position is achieved, in particular, by direct mechanical contact.

[0026] Furthermore, due to the protrusion, the cover element provides a relatively large contact surface on the housing. Even if the expansion of the cover element and the housing differs, and a slight circumferential gap forms between the cover element and the inner side, they still abut against each other (at their end faces). In this case, the protrusion and the cover element operate in a labyrinthine seal manner, thus maintaining a tight seal.

[0027] For example, the cover element is pressed against the protrusion by a cooling body. Optionally, the cover element is located only on the protrusion. However, particularly preferably, the cover element comprises a disc-shaped plastic body, which is particularly formed from a possible matrix. In this case, the plastic body is annular or flat. For example, the matrix includes one or more protrusions offset in or away from the bearing housing. In particular, the protrusions are used to increase the stability of the cover element, and / or these protrusions are located in areas for any openings or passages for pipeline / phase connections.

[0028] The plastic body is arranged on the side facing the electronic device, aligned with the protrusion. Therefore, the plastic body conveniently abuts against the protrusion circumferentially and radially. In other words, the plastic body is specifically inserted into the protrusion. Furthermore, the cover element has a collar arranged on the side of the plastic body facing the electronic device and protruding axially, thus pointing towards the electronic device. The collar overlaps the protrusion in segments. Therefore, the material requirements for the cover element are reduced, and a labyrinth seal is achieved due to the collar, thereby increasing the sealing performance. The collar and plastic body can also be manufactured from different materials, for example, in a 2K injection molding process, and / or the plastic body is injected onto the collar, which is made of a sealing material such as an elastomer or rubber. At least, the collar preferably has increased elasticity, so that a high sealing effect is always present even under different expansion conditions. The collar conveniently rests against the inside of the housing.

[0029] For example, the collar is circumferentially designed, particularly annular. For example, the cooling body is supported on the collar. However, it is particularly preferred that the collar has a radially inwardly extending protrusion that surrounds the free end of the cooling body. In this case, the free end itself abuts against the plastic body and also partially against the protrusion. Therefore, the position of the plastic body is predetermined by the cooling body, and the position of the cooling body is also predetermined by the housing, i.e., the protrusion. In particular, the cooling body can be assembled without applying force to the electronic device, thereby reducing the load on the electronic device. However, a sealing effect is present due to the protrusion. In particular, the collar in the protruding region directly and mechanically abuts against the cooling body. For example, the collar is made of a relatively elastic material, particularly an elastomer or rubber.

[0030] As an alternative or combination to the presence of the collar, another collar projecting in the axial direction is advantageously arranged on the side of the plastic body facing away from the electronic device. This other collar is advantageously annular. For example, the diameter of the annular collar is smaller than that of the protrusion. In particular, the plastic body is stabilized by the other collar, which increases robustness while only slightly increasing the weight of the cover element and the additional space requirement.

[0031] For example, another collar rests directly against the inner side of the housing, thereby stabilizing the cover element. However, it is particularly preferred that the sealing element, such as an O-ring, is arranged radially between the other collar and the inner side. The sealing element is conveniently made of an elastomer or rubber. For example, the other collar has a substantially rectangular cross-section parallel to the radial direction. However, it is particularly preferred that the collar is chamfered and has at least a segmented triangular cross-section, wherein the width of the collar increases in the region of the plastic body. When the cover element is inserted into the protrusion, the sealing element is thus pressed against the other collar and the inner side of the housing, which increases the sealing effect. Alternatively or in combination, the sealing element is inserted, for example, into a groove in the collar or the plastic body, thereby reliably determining the position of the sealing element. It is particularly preferred that the sealing element is attached to the plastic body, for example, by a material-locking manner, which is particularly manufactured together in the 2K process. For example, the plastic of the plastic body is injected onto the sealing element, such that the sealing element is fastened to the plastic body in a way that prevents loss.

[0032] For example, the cooling element is spaced apart from the housing. However, it is particularly preferred that the cooling element is in thermal contact with the housing, allowing the heat of the electronic device to dissipate through the housing. Therefore, the cooling effect is improved. In this case, the cooling element is particularly preferably at least segmentally abutted against the inside of the housing, for example by another component, such as a thermal pad or thermal paste, or for example by direct mechanical contact. In this way, the cooling element is also stabilized by the housing, thereby reducing the load on the electronic device.

[0033] For example, the electric drive includes only one such cooling body. However, particularly preferably, the electric drive includes at least one corresponding second cooling body, by which the cover element is also supported and connected to the electronic device. For example, there are exactly two cooling bodies connected to the electronic device. Optionally, more cooling bodies are provided, preferably fewer than ten. This reduces space requirements. Particularly preferably, the electric drive includes exactly three such cooling bodies. In particular, the position of the cover element is precisely predetermined so that tilting does not occur. Furthermore, there is no over-determination, which is why the desired support of the cover element is always achieved through the cooling bodies, even with relatively high manufacturing tolerances. For example, in this case, some, preferably all, of the cooling bodies are structurally identical to each other, allowing the use of identical components. This reduces manufacturing costs. If a collar is present, then a number of protrusions corresponding to the number of cooling bodies is appropriately present.

[0034] In its assembled state, the auxiliary unit is a component of a motor vehicle and is specifically provided and provided for this purpose. The motor vehicle is, for example, land-based, and such as a truck, bus, or preferably a passenger car. The auxiliary unit has an electric drive. The electric drive includes a housing having a motor compartment and an electronics compartment. An electric motor having a stator and a rotor fastened to a shaft is arranged in the electronics compartment, parallel to the axial direction. Electronic equipment for energizing the motor is arranged in the electronics compartment, and the motor compartment and the electronics compartment are separated by a bearing housing on which bearings for supporting the shaft are connected. A cover element is provided between the electronics equipment and the bearing housing, abutting against the inside of the housing, and a cooling body supported on the cover element is connected to the electronics equipment.

[0035] Another component of the auxiliary unit, such as an adjustment component, is driven, particularly by means of an electric actuator. For example, the electric actuator is a component of an electric pump, such as a water pump, coolant pump, or lubricant pump, such as an oil pump. For example, the auxiliary unit is a transmission. However, particularly preferably, the auxiliary unit is a steering system. In this case, during operation, the electric actuator, for example, supports forces manually applied by the driver. However, the steering system is particularly preferably configured as a "steer-by-wire" system. In this case, a component is driven, particularly by means of an electric actuator, by means of which the steering angle of the vehicle's wheels is predetermined. Specifically, in this case, a rack connected to at least one wheel of the vehicle is driven by the electric actuator, thereby pre-determining the steering angle of the associated wheel by the position of the rack. For example, in this case, the rack is a component of the auxiliary unit, or the latter is driven by the auxiliary unit. In particular, the steering system includes an operating device such as a steering wheel, by means of which, particularly the driver of the vehicle, can pre-determine the steering angle. In this case, preferably, there is a signal coupling / connection between the electric actuator and a sensor assigned to the operating device. Optionally or in combination, an electric drive is coupled to the vehicle's onboard computer or other auxiliary systems, by means of which, in particular, partial or fully autonomous movement or at least steering of the vehicle can be achieved. The invention also relates to a vehicle having such an auxiliary unit.

[0036] The improvements and advantages explained by combining electric drives will also be transferred accordingly to auxiliary units / motor vehicles and between them, and vice versa.

[0037] Embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings. Wherein:

[0038] Figure 1 A motor vehicle with a steering system including an electric drive is schematically shown;

[0039] Figure 2 , 3 The electric drive with a cover element is shown in a perspective sectional view along the axial direction, wherein electronic equipment is not shown;

[0040] Figure 4 It is a partially enlarged cross-sectional view of an electric drive with electronic equipment;

[0041] Figure 5 A perspective view of the cover element is shown, and

[0042] Figure 6 A perspective view of an alternative design for the cover element is shown.

[0043] In all figures, the corresponding parts use the same reference numerals.

[0044] Figure 1 A simplified schematic representation of a motor vehicle 2 in the form of a passenger car is shown. The motor vehicle 2 has a total of four wheels 4, which stand in their intended state on a road (not shown in detail) and are connected to the body 6 of the motor vehicle 2 via a chassis. Two of the wheels 4, namely the two front wheels or optionally the rear wheels, are coupled to an auxiliary unit 8, namely a steering system, by means of which the steering angle of these wheels 4 relative to the body 6 can be adjusted. For this purpose, the auxiliary unit 8 is operatively connected to these wheels 4. The auxiliary unit 8 includes an electric actuator 10, by which a rack (not shown in detail) supported on the two front wheels is driven. During operation of the electric actuator 10, the rack moves laterally, i.e., in a horizontal plane and perpendicular to the longitudinal axis of the motor vehicle 2, thereby changing the steering angle of the rack relative to the body 6 due to the connection of the front wheels.

[0045] The auxiliary unit 8 also includes a sensor 12 associated with the operating device 14, wherein the position of the operating device 14 is detected by means of the sensor 12. The operating device 14 is configured as a steering wheel and is arranged in the interior space of the motor vehicle 2 provided by the body 6. The sensor 12 is signal-connected to the electric drive 10 via a control device / control unit (not shown in more detail). There is no direct mechanical coupling between the operating device 14 and the front wheels of the motor vehicle 2, therefore the steering system is configured as a so-called "steer-by-wire" system.

[0046] Figure 2 An electric drive 10 is shown along the rotation axis 16, and... Figure 3 The details of the electric drive 10 are also shown in a perspective sectional view along the axis of rotation 16. The axis of rotation 16 extends parallel to the axial direction 18, and the radial direction 20 is also predetermined based on the axis of rotation 16. In this case, the radial direction 20 always intersects the axis of rotation 16 at an angle of 90°.

[0047] The electric drive 10 has a housing 22 made of aluminum and having a hollow cylindrical portion 24 arranged concentrically with the axis of rotation 16. A bearing housing 26, arranged perpendicular to the axial direction 18, is surrounded by the hollow cylindrical portion 24 and integrally molded thereon. The housing 22 is subdivided into an electronics compartment 28 and a motor compartment 30 by the bearing housing 26. The inner diameter of the housing 22, i.e., the hollow cylindrical portion 24, is not constant within the electronics compartment 28, but the inner side 32 of the housing 22 has a circumferential protrusion 34 oriented radially inward and formed by a step. In this case, the inner diameter from the step to the bearing housing 26 is constant, and also constant on the side of the step facing away from the bearing housing 26.

[0048] Bearing 36, i.e., a ball bearing, is held by bearing housing 26. In other words, bearing 36 is connected to bearing housing 26. Shaft 38, which is substantially cylindrical and arranged concentrically with the axis of rotation 16, is rotatably supported relative to the axis of rotation 16 by means of bearing 36. Shaft 38 extends through bearing housing 26 and is partially located within electronics compartment 28. Shaft 38 also extends through the entire motor compartment 30. The motor compartment 30 is closed at the end opposite bearing housing 26 by another bearing housing 40, through which another bearing 42 is held. Shaft 38 is also supported by another bearing, which also extends through another bearing housing 40 forming the bearing housing on side A. Gear 44 or pinion is connected to the end of shaft 38 passing through the other bearing housing 40, and in the assembled state engages with a rack or belt (not shown in more detail).

[0049] An electric motor 46 is arranged in a motor housing 30 and is designed as a brushless direct current motor (BLDC) with a hollow cylindrical stator 48. The stator 48 is circumferentially fastened to the inner side 32 of the housing 22 and surrounds a similarly hollow cylindrical rotor 50 fastened to a shaft 38. The stator 48 and rotor 50 are arranged concentrically with respect to the axis of rotation 16. The stator 48 includes a plurality of electromagnets (not shown in detail), each formed at least partially by an electric coil. The electric coils are connected together, totaling two three-phase, forming a star circuit in each case. The rotor 50 has a laminated core in which permanent magnets (not shown in detail) are embedded. In summary, the electric motor 46 is arranged in a motor housing 30 having a stator 48 and a rotor 50 torsionally fastened to a shaft 38.

[0050] Electric drive 10 includes Figure 4 The electronic device 52 is shown. In a cross-sectional view along the axis of rotation 16, the electric drive 10 is shown segmentally. The electronic device 52 has a disc-shaped printed circuit board 54 arranged perpendicular to the axial direction 18 and located in the electronic device compartment 28. Electrical and / or electronic components (not shown in more detail) are fastened to and appropriately interconnected on the printed circuit board 54, and a bridging circuit is also implemented. The latter is electrically connected to the stator 48 via conduits not shown in detail, so that the operation of the motor 46 occurs through the electronic device 52. In summary, the electronic device 52 is used to energize the motor 46.

[0051] A total of three cooling elements 56 are connected to the electronic device 52, namely the printed circuit board 54, two of which are located in... Figure 4The diagram is schematically shown in a simplified manner. The cooling elements 56 are structurally identical and are made of aluminum. The cooling elements 56 are in thermal contact with semiconductor switches, for example, forming a bridging circuit, and are located on the side of the printed circuit board 54 facing the bearing housing 26. In this case, the cooling elements 56 are designed in a finger-like shape and extend parallel to the axial direction 18. Furthermore, each cooling element 56, offset from the others relative to the axis of rotation 16, abuts against the inner side 32 of the housing 22. Therefore, during operation, heat is released from the cooling elements 56 to the housing 22 and from there to the environment.

[0052] A cover element 58 is provided between the electronic device 52 and the bearing cover 26, which... Figure 5 The electronic device 52 is shown in a side view. In this case, an additional space 60 is formed between the cover element 58 and the bearing cover 26 to form an electronic device compartment 28, in which the end of the shaft 38 and the components for determining the angular position of the shaft 30 relative to the housing 22 are located. In this case, the additional space 60 has a reduced inner diameter compared to other components of the electronic device compartment 28 due to the protrusion 34.

[0053] The cover element 58 has a disc-shaped plastic body 62 arranged substantially perpendicular to the axial direction 18. In this case, the plastic body 62 not only lies in a single plane but also has three distinct protrusions 64 pointing in the direction of the bearing housing 26. Each protrusion 64 has multiple openings 66 through which the electronic device 52 passes via its conduit electrically connected to the motor 46. In this case, the openings are formed in a sealing element 70, which is composed of more than one elastomer and is injection molded from the rigid plastic forming the remainder of the plastic body 62. In this case, the openings 66 have a smaller cross-section than the conduit through which they pass, resulting in close contact between them, thereby preventing particles from passing through. The plastic body 62 also has additional inserts 72, which are also made of elastomer and are used to manufacture the cover element 58 in a two-component injection molding process.

[0054] A plastic body 62 is arranged on the side facing the electronic device 52, aligned with the protrusion 34. Thus, the protrusion 34 circumferentially surrounds the plastic body 62, and in the axial direction 18, the plastic body 62 terminates at the same height as the protrusion 34. In this case, the plastic body 62 circumferentially abuts against the protrusion 34. Furthermore, a collar 74 is fastened to the plastic body 62 on the side facing the electronic device 52. Therefore, the collar 74 protrudes in the axial direction 18. The collar 74 is made, for example, of rigid plastic or an elastomer. The collar 74 is substantially annular but has a larger diameter than the plastic body 62. As a result, the protrusion 34 is overlapped by the collar 74. Therefore, the collar 74, and thus the cover element 58, is located on the protrusion 34 on the side away from the electronic device 52, and a labyrinthine seal is formed by the cover element 58 and the protrusion 34, preventing or at least hindering the passage of particles or liquids.

[0055] Unlike the annular shape, the collar 74 has three protrusions 76 extending inward in the radial direction 20. Thus, through the protrusions 76, the collar 74 protrudes inward in an arc at three points. In the region of the protrusions 76, the collar 74 does not rest against the protrusion 34. In each case, the free end of a cooling element 56 engages in each protrusion 76, such that the end side of each cooling element 56 abuts the protrusion 34 and a portion of the plastic body 62 located there. In summary, in each case, the free end of a cooling element 56 is thus surrounded by each protrusion 76. Therefore, the cooling element 56 is supported on the cover element 58. In summary, the three cooling elements 56 supported on the cover element 58 are thus connected to the electronic device 52.

[0056] As a result, the position of the cooling body 56 is determined by the protrusion 34, which in turn determines the position of the plastic body 62, and thus the position of the cover element 58, i.e., its distance from the electronic device 52. In this case, the position of the cover element 58 relative to the bearing cover 26 is predetermined by the collar 74 and its contact with the protrusion 34. If the housing 22 and the cover element 58 are heated, this causes different expansions, so that the collar 74 no longer abuts against the inner side 32 of the housing 22, thus forming a circumferential gap between the inner side 32 of the housing 22 and the collar 74. However, due to the support of the cooling body 56, the collar 74 also continues to remain on the protrusion 34, so that the labyrinth seal remains and prevents particles from passing through.

[0057] To enhance sealing, an additional ring 78 projecting axially in the direction 18 is provided on the plastic body 62 on the side away from the electronic device 52, thus pointing towards the bearing housing 26. This additional ring 78 is entirely annular and made of rigid plastic. The additional ring 78 has a boundary surface inclined relative to the inner side 32, and a sealing element 80 is disposed between this boundary surface and the inner side 32 of the housing 22. The sealing element 80 is formed of an O-ring made of plastic or rubber. Alternatively, the sealing element 80 is made of an elastomer, with the plastic body 62 integrally molded onto the elastomer.

[0058] Due to the inclined boundary surface (chamfer) of the other ring 78, when the cover element 58 is inserted into the electronics compartment 28 between the other ring 78 and the inner side 32, the sealing element 80 is pressed between the other ring 78 and the inner side 32, thereby increasing the sealing performance. In summary, the sealing element 80 is arranged radially 20 between the other ring 78 and the inner side 32.

[0059] Figure 6 An alternative embodiment of the cover element 58 is shown in perspective. In this case, the shape of the cover element 58 remains substantially unchanged. Therefore, the cover element 58 also includes a plastic body 62, a protrusion 64, and a collar 74 with three protrusions 76. However, the cover element 58 is made solely of rigid plastic. In other words, there is no sealing element 70 and an insert 72, and these are provided by a rigid plastic material. The sealing element 80 is also absent. An opening 66 is also present, wherein its cross-section is the same as or slightly larger than the cross-section of the respective conduit used. The type assembled in the electric drive 10 corresponds to the previous embodiment. Therefore, particularly in this case, the cooling body 56 is also supported on the cover element 58 in the region of the protrusions 76.

[0060] Manufacturing costs are reduced due to the simplified design of the cap element 58. However, the sealing performance is slightly reduced. For example, to provide improved sealing after the pipe insertion opening 66, it is surrounded by a further seal that makes it more difficult for particles to pass through there.

[0061] This invention is not limited to the exemplary embodiments described above. Rather, those skilled in the art can derive other variations of the invention therefrom without departing from its subject matter. Furthermore, in particular, all the various features described in connection with the embodiments can be combined with each other in other ways without departing from the subject matter of the invention.

[0062] List of reference numerals

[0063] 2 motor vehicles

[0064] 4 wheels

[0065] 6-body

[0066] 8 auxiliary units

[0067] 10 Electric Drives

[0068] 12 sensors

[0069] 14 Operating Equipment

[0070] 16 Rotation Axis

[0071] 18 axial directions

[0072] 20 radial direction

[0073] 22 shell

[0074] 24 hollow cylindrical parts

[0075] 26 Bearing Cover

[0076] 28 Electronic Equipment Cabin

[0077] 30 motor compartment

[0078] 32 inner side

[0079] 34 protrusions

[0080] 36 bearing

[0081] 38 axes

[0082] 40 Another bearing cover

[0083] 42 Another bearing

[0084] 44 gears

[0085] 46 electric motors

[0086] 48 stator

[0087] 50 rotor

[0088] 52 electronic devices

[0089] 54 Printed Circuit Boards

[0090] 56 cooling body

[0091] 58 Cover Components

[0092] 60 additional spaces

[0093] 62 plastic body

[0094] 64 convex part

[0095] 66 opening

[0096] 70 sealing elements

[0097] 72 inserts

[0098] 74 rings

[0099] 76 protrusions

[0100] 78 Another set of rings

[0101] 80 sealing elements

Claims

1. An electric drive (10) for a motor vehicle (2), particularly a steering motor, comprising a housing (22) having a motor compartment (30) and an electronics compartment (28). -in, The electric motor (46) is housed in the motor compartment (30) and has a stator (48) and a rotor (50) fastened to a shaft (38) arranged parallel to the axial direction (18). -Among them, the electronic equipment (52) for energizing the motor (46) is arranged in the electronic equipment compartment (28), -The motor compartment (30) and the electronic equipment compartment (28) are separated by a bearing cover (26), on which a bearing (36) for supporting the shaft (38) is connected. -The cover element (58) is disposed between the electronic device (52) and the bearing cover (26), abutting against the inner side (32) of the housing (22), and -The cooling body (56) is connected to the electronic device (52), which is supported on the cover element (58).

2. The electric drive (10) according to claim 1. Its features are, The inner side (32) has a circumferential protrusion (34), on which the cover element (58) rests on the side facing away from the electronic device (52).

3. The electric drive (10) according to claim 2. Its features are, The cover element (58) has a disc-shaped plastic body (62) which is disposed on the side facing the electronic device (52) aligned with the protrusion (34) and has a collar (74) that protrudes in the axial direction (18) and overlaps the protrusion (34) at least segmentally on the side facing the electronic device (52).

4. The electric drive (10) according to claim 3. Its features are, The collar (74) has a protrusion (76) extending inward in the radial direction (20) by surrounding the free end of the cooling body (56).

5. The electric drive (10) according to any one of the preceding claims. Its features are, Another ring (78) protruding along the axial direction (18) is arranged on the plastic body (62) on the side opposite to the electronic device (52).

6. The electric drive (10) according to claim 5. Its features are, The sealing element (80) is arranged in the radial direction (20) between the other ring (78) and the inner side (32).

7. The electric drive (10) according to any one of claims 1 to 6. Its features are, The cooling body (56) abuts against the inner side (32) of the housing (22) at least in sections.

8. The electric drive (10) according to any one of claims 1 to 6. Its features Three such cooling bodies (56).

9. An auxiliary unit (8) of a motor vehicle (2), particularly a steering system, having an electric drive (10) according to any one of claims 1 to 8.

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