industrial truck comprising a steering motor

Abstract

A forklift truck comprising a drive unit, at least one driven wheel rotatably mounted on the drive unit about its vertical axis, a drive motor driving the at least one wheel, and an integrated steering motor comprising a three-phase motor, an inverter supplying the three-phase motor, and a housing enclosing the three-phase motor and the inverter, wherein the steering motor is attached to the drive unit in such a way that switching on the motor changes the angle of rotation between the at least one wheel and the drive unit, characterized in that a. the inverter comprises power semiconductors based on a semiconductor material with a large band gap of more than 3 eV, preferably based on a semiconductor material with a large band gap of more than 3.3 eV and particularly preferably made of GaN, and b. no means are available for actively cooling the steering motor.

Description

[0001] The invention relates to a forklift truck comprising an integrated steering motor and an integrated steering motor for a forklift truck.

[0002] Industrial trucks typically consist of a drive unit to which at least one driven wheel is attached. The driven wheel is mounted to the drive unit in such a way that it can rotate around the truck's vertical axis. A steering motor is used to change the angle of rotation between the wheel and the drive unit. This steering motor is usually powered by the same battery that supplies power to the drive motor that drives the wheel. The industrial truck travels in a direction determined primarily by the angle of rotation between the vertical axis and the drive unit. To change the truck's direction of travel, the steering motor is switched on, and the angle of rotation of the drive wheel changes accordingly, depending on the direction of current flow.

[0003] Especially in modern steering motors, a design is chosen in which an electric motor and its power supply, such as an inverter, are arranged together in a single housing. Such an integrated steering motor can be manufactured in a particularly space-saving manner.

[0004] Steering motors present a challenge, particularly during frequent steering maneuvers, as they repeatedly draw high power, leading to significant heat generation. Therefore, cooling the steering motor is crucial, a task made more difficult by the need for a compact design. This compact design allows ample space for other components of the industrial truck located above or near the driven wheel, such as the drive motor or a hydraulic unit.

[0005] In an integrated steering motor design, heat generation plays a particularly important role because the power electronics are located in close proximity to the three-phase motor and can be irreparably damaged by overheating. For this reason, it may be necessary to implement a relatively complex active cooling system, which, due to space constraints, involves considerable design effort.

[0006] DE 10 2008 003 863 A1 relates to an electric drive for a forklift truck comprising an electric motor with a housing and motor shaft, an electronic control unit for the motor, and a fan unit for the motor and the electronic control unit. A cup-shaped cover surrounds the control unit from the outside, leaving a gap and a free space. A fan ensures that turbulent airflow is created in this gap and free space. This application illustrates the effort required to cool an integrated motor in a forklift truck.

[0007] In recent years, novel materials with band gaps exceeding 3 eV have become available for various power semiconductors. These include, in particular, gallium nitride (GaN) and silicon carbide (SiC). Power semiconductors based on these materials can operate at higher switching frequencies than conventional silicon-based semiconductors such as silicon MOSFETs. Furthermore, the use of GaN, for example, reduces dead time during switching. This allows for the production of inverters with lower switching losses and, consequently, higher efficiency.

[0008] Based on this, the invention aims to provide an integrated steering motor for a forklift truck that is as compact as possible and easy to integrate into the forklift truck.

[0009] The problem is solved by a forklift truck with the features of claim 1 and an integrated steering motor with the features of claim 2. Advantageous embodiments are described in the dependent claims and in the description.

[0010] The industrial truck according to the invention comprises a drive unit, at least one driven wheel rotatably mounted on the drive unit about its vertical axis, and a drive motor driving the at least one wheel. Furthermore, an integrated steering motor is provided. The steering motor comprises a three-phase motor and an inverter supplying the three-phase motor, as well as a housing enclosing the three-phase motor and the inverter. Preferably, it is a three-phase asynchronous motor. The steering motor is attached to the drive unit such that switching on the three-phase motor changes the angle of rotation between the at least one wheel and the drive unit.

[0011] The inverter of the industrial truck according to the invention comprises power semiconductors made from a semiconductor material with a large band gap of more than 3 eV. Preferably, the semiconductor material is based on a semiconductor material with a band gap of more than 3.3 eV and is particularly preferably made of gallium nitride (GaN). The power semiconductors can be switching elements such as transistors.

[0012] Furthermore, there are no means for actively cooling the steering motor. The absence of such means specifically means that neither liquid cooling nor active air cooling is provided for the steering motor. Therefore, there are no fans or pumps, nor any corresponding lines or connections.

[0013] The inverter's power semiconductors, based on a wide-bandgap semiconductor material, allow the integrated steering motor to operate with reduced losses. As a result, less waste heat is generated in the integrated steering motor, which could damage or shorten the lifespan of the power semiconductors, thus eliminating the need for active cooling.

[0014] The reduced losses are primarily due to the fact that, thanks to the use of power semiconductors based on a wide-bandgap semiconductor material, the inverter can operate at a higher switching frequency than is possible with conventional power semiconductors. This higher switching frequency results in reduced current ripple, which in turn lowers losses in the three-phase motor. Consequently, significantly less heat is generated in the three-phase motor due to losses compared to steering motors whose inverters are equipped with conventional power semiconductors. Furthermore, the reduced current ripple, in particular, leads to a reduction in vibrations.

[0015] In summary, the use of wide bandwidth power semiconductors allows the inverter and, in particular, the three-phase machine to be operated so efficiently that no active cooling of the integrated steering motor is necessary.

[0016] In this way, the steering motor can be made particularly small because it does not require connections for active cooling or corresponding pumps or fans. Furthermore, the steering motor according to the invention can be easily integrated into the industrial truck because, for example, no additional cooling channel routing or other design limitations resulting from active cooling need to be considered.

[0017] Furthermore, a high switching frequency results in high steering precision. This is particularly advantageous when the steering motor is to be used in an automated guided vehicle (AGV).

[0018] The integrated steering motor for a forklift truck according to the invention comprises a closed housing with an external DC connection and a three-phase motor arranged in the housing with a drive shaft protruding from the housing. Furthermore, an inverter is arranged in the housing. The inverter comprises power semiconductors based on a semiconductor material with a wide band gap of more than 3 eV. Preferably, the inverter comprises power semiconductors based on a semiconductor material with a band gap of more than 3.3 eV, and particularly preferably on GaN. A "closed housing" is understood to mean a housing that, in a fully assembled state of the steering motor, completely surrounds the three-phase motor and the inverter and has openings only for means of mechanical force or torque transmission, such as the drive shaft, or for electrical contacts.

[0019] Furthermore, the housing is designed such that no active cooling means are required for the operation of the inverter. Preferably, the housing has neither connections for a coolant, openings for cooling air supply, pumps for circulating a coolant, nor fans for cooling. It is also preferred that the housing has no external fittings to which objects can be attached or with which such objects can be attached to the housing, such as mounting rails.

[0020] As previously described, the advantage of the integrated steering motor according to the invention lies in the fact that the use of wide-bandgap power semiconductors results in particularly efficient operation of the three-phase motor, which generates the majority of the power losses of all subcomponents. The inverter also operates more efficiently. Consequently, no active cooling is required for the same power output as with an inverter equipped with conventional power semiconductors. Thus, the integrated steering motor can be made smaller and more easily integrated mechatronically into the industrial truck.

[0021] According to one embodiment, the inverter has a control device configured to switch the power semiconductors at a switching frequency of more than 30 kHz, preferably 50 kHz, and particularly preferably more than 60 kHz. Preferably, the control device switches the power semiconductors in pulses.

[0022] The control device preferably switches the power semiconductors using pulse-width modulation. The higher switching frequency of the inverter, compared to an inverter based on conventional power semiconductors, reduces current ripple. This, in turn, lowers the losses in the three-phase machine caused by harmonic overtones. In this way, the control device, which switches at a frequency of more than 30 kHz, preferably 50 kHz, and particularly preferably more than 60 kHz, enables the three-phase machine to operate with high efficiency. The high efficiency of the three-phase machine eliminates the need for active cooling.

[0023] In one embodiment, the power semiconductors are field-effect transistors without a body diode. Preferably, these are high-electron-mobility transistors. Using power semiconductors without a body diode results in a very short dead time when driving the power semiconductors in the inverter. This reduces the harmonic distortion in the torque of the three-phase machine, allowing for a higher usable torque from the machine. Furthermore, the losses in the inverter are also reduced. For the same power output, lower losses and less heat generation are therefore possible. GaN is particularly suitable as a material for such power semiconductors.

[0024] In one embodiment, the power semiconductors are arranged on a printed circuit board (PCB), and conductors leading from the power semiconductors to the three-phase motor, each assigned to a specific phase of the motor, are present. These conductors are embedded, at least in sections, in the PCB and arranged one above the other. Alternatively or additionally, the conductors extend, at least in sections, side by side between the three-phase motor and the PCB. Also alternatively or additionally, the conductor terminals are arranged planarly next to each other on the PCB. This arrangement of the conductors, assigned to the different phases, creates a capacitor between each conductor during operation. Crucially, the conductors are routed in close proximity to one another.Preferably, the conductors in the cables and / or their connections are spaced less than 5 cm apart, particularly preferably less than 3 cm apart. The conductors in the printed circuit board(s) are spaced less than 1 mm apart, particularly preferably 160 µm apart.

[0025] The resulting capacitors allow the power semiconductors to be switched with the sharpest possible switching edges, i.e., exhibiting a high time gradient, without the voltage applied to the three-phase machine exhibiting strong time gradients. Strong time gradients in the voltage applied to the three-phase machine could lead to insulation faults and generally reduce the service life of the three-phase machine.

[0026] The integration of capacitors between the conductors allows the full advantages of the wide-bandwidth semiconductor material to be exploited without negatively impacting the three-phase motor. This described conductor design thus enables the advantages of the semiconductor material to be implemented particularly effectively. It should be noted, however, that such a conductor design is only possible in an integrated steering motor with a correspondingly close arrangement of the inverter, three-phase motor, and conductors.

[0027] According to one embodiment, the capacitance of a single capacitor forming between the respective conductors is greater than 100 pF, preferably greater than 300 pF, and particularly preferably greater than 500 pF. Capacitances of this magnitude, as previously described, make it possible to reduce the negative effects on the three-phase machine. The capacitance is designed for the components used and the specific application. It should be noted that such capacitors form between the conductors, resulting in a total capacitor with a total capacitance that depends on the individual capacitances.

[0028] According to one design, the inverter has a B6 topology. This is a standard inverter configuration in which six switchable power semiconductors are used to convert the direct current (DC) applied to the inverter's input into three-phase alternating current (AC).

[0029] According to one embodiment, the housing has a primary direction of expansion. The primary direction of expansion and the output shaft axis are parallel to each other. In particular, the housing according to this embodiment can be cylindrical. Furthermore, it has a mounting cover on only one side. The mounting cover closes a mounting opening, which can be located on a surface of the housing opposite the output shaft. This allows for particularly easy assembly and disassembly of all the electronics housed in the enclosure, including the inverter and the three-phase motor. For this purpose, the aforementioned components are inserted or removed axially through a mounting opening closed by the mounting cover. Such simple assembly is made possible, in particular, by the absence of coolant lines or other means of active cooling.

[0030] According to one embodiment, the housing has only sealed openings through which machine elements for power transmission are routed. The housing therefore has no openings for coolant or cooling air supply. Instead, it only provides openings through which machine elements, such as the output shaft, protrude. These openings can be sealed with appropriate gaskets, thus achieving the high level of dust and moisture protection required in industrial trucks.

[0031] According to one embodiment, the housing has a single opening from which the output shaft of the three-phase machine protrudes.

[0032] According to one embodiment, at least one heat transfer element is arranged in the housing, which makes thermal contact exclusively with an inner wall of the housing and the power semiconductors. Preferably, this element is a heat-conducting plate. Contact elements may be present between the inner wall of the housing and the heat transfer element, and / or between the power semiconductor and the heat transfer element. The thermally conductive transition between the housing and the power semiconductors enables efficient heat dissipation to the housing. Arranging the at least one heat transfer element directly between the inner wall of the housing and the power semiconductors allows for a particularly compact design.

[0033] The housing can be made of metal, which gives it high thermal conductivity. This can be used to allow it to heat up quickly via the thermally conductive connection to the power semiconductors through the at least one heat transfer element. It then dissipates the heat generated in the power semiconductors as efficiently as possible.

[0034] Furthermore, the power semiconductors can be arranged on a printed circuit board (PCB), with the minimum heat transfer element and the power semiconductors positioned between the inner wall and the PCB. Therefore, no heat transfer elements need to pass through or under the PCB. Instead, the heat transfer means can be located on the top surface where the power semiconductors are situated. This avoids the need for complex heat transfer elements to dissipate the heat generated in the power semiconductors to the housing via thermal conduction. This allows for a particularly compact design.

[0035] According to one design, the conductors extending between the three-phase motor and the circuit board are stranded wires with lamellar contacts or copper busbars. These types of conductors are easy to manufacture and install.

[0036] In one embodiment, the power semiconductors are arranged on a printed circuit board (PCB) that is oriented perpendicular or parallel to the output shaft. This PCB arrangement allows for a more compact configuration of the integrated steering motor. Furthermore, the use of wide-bandgap power semiconductors, such as GaN, provides greater design freedom, enabling PCB placement tailored to the specific application.

[0037] According to one design, the housing surrounding the inverter is smooth on the outside or has at least partially protruding cooling fins. While a smooth housing is particularly easy to integrate into the forklift truck, cooling fins allow for the greatest possible heat flow from the inside of the housing to the environment, thus enabling effective cooling of the three-phase motor and the inverter.

[0038] In one design, the inverter has a circuit board with an integrated current sensor. This can be, in particular, a Hall sensor. Integrating the current sensor into the circuit board allows for easy installation.

[0039] According to one embodiment, the inverter has a printed circuit board (PCB) with a cutout through which the output shaft or a speed sensor shaft rigidly connected to the output shaft protrudes. Furthermore, a speed sensor is arranged on the PCB for detecting the rotational speed of the output shaft. Preferably, the output shaft or the speed sensor shaft has a signal generator, which may, for example, be a permanent magnet. The speed sensor can generate a speed signal directly by measuring at the output shaft or indirectly by measuring at the speed sensor shaft. The PCB on which the speed sensor is arranged can be the same PCB on which the power semiconductors are mounted. However, it can also be a different PCB, in particular one on which the control unit is mounted.

[0040] According to one embodiment of the industrial truck according to the invention, its steering motor has one or more features of the integrated steering motor according to the invention and / or one of its embodiments described above.

[0041] The invention is explained in more detail below with reference to the exemplary embodiment shown in the accompanying drawings. The figures show: Fig. 1: A three-dimensional view of a steering motor; Fig. 2: a schematic sectional view of a steering motor; Fig. 3a: a schematic sectional view of a steering motor with heat sink; Fig. 3b: a schematic sectional view of a steering motor with a heat sink and a vertically arranged circuit board; Fig. 4a: a detailed view of the steering motor, showing superimposed conductors embedded in a circuit board; Fig. 4b: a detailed view of Fig. 4a, which shows the formation of capacitors between the embedded conductors; Fig. 5: a three-dimensional sectional view of a steering motor, showing the routing of the electrical conductors between the three-phase machine and the inverter; Fig. 6: a three-dimensional view of a power component having planar conductor connections; Fig. 7: A top view of a control unit with a speed sensor.

[0042] Fig. Figure 1 shows a three-dimensional view of a steering motor 1 for a forklift truck. A housing 2, an inverter 3, a three-phase motor 4 arranged in the housing 2, and an output shaft 5 protruding from the housing 2 are shown. The upper section of the housing 2 is shown in section, revealing the inverter 3 located there. For clarity, the wiring between the inverter 3 and the three-phase motor 4, which extends through the motor shield 6, is not shown in this figure. This also applies to electrical connection elements located on the housing 2. Furthermore, a mounting opening 7 is shown in the upper part of the housing 2. When installed in a forklift truck, this opening is closed by a screwed-in insert, thus closing the housing 2.

[0043] In Fig. Figure 2 shows a schematic sectional view of the steering motor 1. The illustration shows that the inverter 3 is located above the three-phase motor 4 inside the housing 2 and that the output shaft 5 protrudes from the housing 3. The heat sink 8, which is in contact with the housing 2, is also shown. As can be seen from Fig. As can be seen in Figure 1, the cooling fins of the heat sink 8 can also be integrated into the housing 2.

[0044] Furthermore, the representation in Fig. 2. The inverter 3 in more detail. It can be seen that the inverter 3 has a power section 9 and a control section 10. The power section 9 is arranged above the control section 10, with capacitors 11 arranged on the top of the power section 9 and power semiconductors 12 arranged on the bottom of the power section 9. In summary, the Fig. 2, that inverter 3 and three-phase machine 4 are integrated into the common housing 2.

[0045] Fig. Figure 3a shows a sectional view of another steering motor 13. Like steering motor 1, steering motor 13 also comprises a power unit 14, a control unit 15, and a three-phase motor 16. In contrast to steering motor 1, steering motor 13 has power semiconductors 17 arranged on the top surface of the power unit 14. Furthermore, the heat sink 18 is arranged directly on the power semiconductors 17, so that it is in direct contact with them, and the power semiconductors 17 are located between the power unit 14 and the heat sink 18. Such an arrangement is not usually possible with conventional silicon semiconductors, but it is possible with the semiconductors used according to the invention, which have a material with a large band gap.

[0046] Fig. Figure 3b shows another steering motor 19 in a schematic sectional view. Steering motor 19 also comprises a three-phase motor 20, a control unit 21, and a power unit 22. The power semiconductors 23 are arranged on the control unit 22, and the heat sink 24 is arranged directly on the power semiconductors 23. The power semiconductors 23 and the heat sink 24 are in direct contact, and the heat sink 24 is in contact with the environment. However, the power unit 22, with the attached power semiconductors 23 and the heat sink 24, is not arranged above the three-phase motor 20, but next to it. Therefore, the power semiconductors 23 and the heat sink 24 are also located next to the steering motor 20. In this way, steering motor 19 can be made axially shorter by the difference Δ than steering motor 13. Besides saving space, this also simplifies assembly.

[0047] Fig. Figure 4a shows a detailed view of the steering motor 1, in which superimposed conductors 26 embedded in the circuit board 25 form a high-frequency loop 27. This loop creates a capacitance between the conductors 26. Furthermore, in Fig. 4a Detail A is circled with a dashed line.

[0048] Fig. 4b shows detail A of the Fig. 4a, in this detailed view the formation of capacitors 28 between the current conductors 26 embedded in the circuit board 25 can be seen. In the area of ​​detail A, where a connection with the power section located below takes place, the current conductors 26 are embedded vertically one above the other in the circuit board 25.

[0049] The high-frequency loop 27 and the capacitors 28 ensure that the power semiconductors can be switched at a very high frequency and with sharp switching edges without damaging the three-phase machine. The high switching frequency and sharp switching edges allow for a reduction in current ripple, thus reducing losses in the three-phase machine. The use of capacitors therefore allows the potential for high switching frequencies and sharp switching edges offered by materials with a large bandgap to be fully exploited, thereby avoiding losses in the three-phase machine.

[0050] Fig. Figure 5 shows a three-dimensional sectional view of the steering motor 1. The compact design of the integrated steering motor 1 is particularly evident from this illustration, as the conductors 29 can be arranged so that they are directly adjacent to one another. This allows capacitors to form between them, which is advantageous as explained above. Furthermore, it can be seen that the conductors 29 are connected to the inverter 3 via conductor terminals 30. These terminals promote the formation of beneficial capacitors.

[0051] Fig. Figure 6a shows a three-dimensional view of a power section 10, which has planarly arranged conductor connections 30'. These allow capacitors to form between the conductors 29 (not shown). The power connection 31, via which the steering motor can be connected to a power supply, is also visible.

[0052] Fig. Figure 6b shows an alternative embodiment of the conductor terminals 30' in the form of the conductor terminals 30", which have terminal-shaped plug-in contacts and allow greater capacitive decoupling.

[0053] Fig. Figure 7 shows a top view of a control unit 11 with a speed sensor 32. The speed sensor 32 is mounted at the edge of a central bore 33 in the control unit 11. The speed encoder shaft 34, which rotates in the same direction as the output shaft 5, extends through the bore 33 and has a speed encoder 35 mounted on it. Due to the small distance between the speed encoder 35 and the speed sensor 32, the speed sensor 32 can determine the rotational speed. The speed sensor 32 is a Hall sensor and the speed encoder 35 is a permanent magnet. Reference symbol: 1 steering motor 2 cases 3 inverters 4 Three-phase machine 5 Output shaft 6 Engine shield 7 Mounting opening 8 heat sinks 9 Performance section 10 Control unit 11 capacitors 12 Power semiconductors 13 Steering motor 14 Performance section 15 Control unit 16 Three-phase machine 17 Power semiconductors 18 heat sinks 19 Steering motor 20 Three-phase machine 21 Control unit 22 Performance section 23 Power semiconductors 24 heat sinks 25 circuit boards 26 electrical conductors 27 High-frequency loop 28 capacitors 29 leaders 30 conductor connections 31 Power connection 32 Speed ​​sensor 33 bore 34 Speed ​​sensor shaft 35 Speed ​​sensors QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2008 003 863 A1

[0006]

Claims

[1] Industrial truck comprising a drive unit, at least one driven wheel rotatably mounted on the drive unit about its vertical axis, a drive motor driving the at least one wheel and an integrated steering motor (1, 13, 19) comprising a three-phase machine (4), an inverter (3) supplying the three-phase machine (4) and a housing (2) enclosing the three-phase machine and the inverter, wherein the steering motor (1, 13, 19) is attached to the drive unit in such a way that switching on the motor changes the angle of rotation between the at least one wheel and the drive unit, characterized by , that a. the inverter (3) comprises power semiconductors (12, 17, 23) which are based on a semiconductor material with a large band gap of more than 3 eV, preferably on a semiconductor material with a large band gap of more than 3.3 eV and particularly preferably made of GaN, and b. no means for active cooling of the steering motor (1, 13, 19) are available. [2] Integrated steering motor (1, 13, 19) for a forklift truck comprising a. a closed housing (2) with an external DC connection, b. a three-phase machine (4) arranged in the housing (2) with an output shaft (5) protruding from the housing and c. an inverter (3) arranged in the housing (2), characterized by , that d. the inverter comprises power semiconductors (12, 17, 23) based on a semiconductor material with a large band gap of more than 3 eV, preferably based on a semiconductor material with a large band gap of more than 3.3 eV and particularly preferably GaN, e. the housing (2) is designed in such a way that no means for active cooling are required for the operation of the inverter (3). [3] Integrated steering motor (1, 13, 19) according to claim 2, characterized bythat the inverter (3) has a control device which is configured to switch the power semiconductors (12, 17, 23) at a switching frequency of more than 30 kHz, preferably 50 kHz, particularly preferably more than 60 kHz. [4] Integrated steering motor (1, 13, 19) according to one of claims 2 or 3, characterized by , that the power semiconductors (12, 17, 23) are field-effect transistors that do not have a body diode. [5] Integrated steering motor (1, 13, 19) according to one of claims 2 to 4, characterized by, that the power semiconductors (12, 17, 23) are arranged on a printed circuit board (25) and that current conductors (26, 29) leading from the power semiconductors to the three-phase machine and assigned to the phases of the three-phase machine (4) are present, which are embedded at least sectionally in the printed circuit board (25) and arranged one above the other and / or which extend at least sectionally next to each other between the three-phase machine (4) and the printed circuit board (25) and / or whose terminals (30) are arranged planarly next to each other on the printed circuit board (25), so that a capacitor (28) is formed between the conductors (26, 29) during operation. [6] Integrated steering motor (1, 13, 19) according to claim 5, characterized by , that the capacitance of the capacitor (28) is more than 100 pF, preferably more than 300 pF and particularly preferably more than 500 pF. [7] Integrated steering motor according to one of claims 5 or 6, characterized by, that the conductors (29) extending between the three-phase machine (4) and the circuit board (25) are stranded wires with lamellar contacts or copper busbars. [8] Integrated steering motor (1, 13, 19) according to one of claims 2 to 7, characterized by , that the inverter (3) has a B6 topology. [9] Integrated steering motor (1, 13, 19) according to one of claims 2 to 8, characterized by , that the housing (2) has a main direction of expansion, in particular is cylindrical, and has a mounting cover only on one side, wherein the main direction of expansion and the output shaft axis are parallel. [10] Integrated steering motor (1, 13, 19) according to any one of claims 2 to 9, characterized by , that the housing (2) has exclusively sealed openings through which machine elements are guided for power transmission. [11] Integrated steering motor (1, 13, 19) according to claim 10, characterized by, that the housing has a single opening from which the output shaft (5) of the three-phase machine (4) protrudes. [12] Integrated steering motor (1, 13, 19) according to one of claims 2 to 11, characterized by , that at least one heat transfer element (8, 18, 24) is arranged in the housing (2) which thermally contacts only an inner wall of the housing (2) and the power semiconductors (12, 17, 23), and the power semiconductors (12, 17, 23) are arranged on a printed circuit board (25) such that the heat transfer element (8, 28, 24) and the power semiconductors (12, 17, 23) are arranged between the inner wall and the printed circuit board (25). [13] Integrated steering motor (1, 13, 19) according to one of claims 2 to 12, characterized by , that the power semiconductors (12, 17, 23) are arranged on a printed circuit board (25) which is oriented perpendicular or parallel to the output shaft (5). [14] Integrated steering motor (1, 13, 19) according to one of claims 2 to 13, characterized by that the housing (2) in the area where it surrounds the inverter (3) has smooth or at least partially protruding cooling fins on the outside. [15] Integrated steering motor (1, 13, 19) according to one of claims 2 to 14, characterized by that the inverter has a circuit board into which a current sensor, in particular a Hall sensor, is integrated. [16] Integrated steering motor (1, 13, 19) according to any one of claims 2 to 15, characterized by , that the inverter has a circuit board (25) which has a recess through which the output shaft (5) or a speed sensor shaft (34) rigidly connected to the output shaft protrudes and a speed sensor (33) is arranged on the circuit board which detects the speed of the output shaft (34).

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