Compact drive system for a conveyor belt

Abstract

The invention relates to a drive system (1) for a belt conveyor system (2), comprising at least one electric working machine (3), a transmission (4) and a drive drum (5) which is connected to a belt of a belt conveyor system (2), wherein the electric working machine has a nominal rotational speed (3) of between 5000 rpm and 15000 rpm, wherein the transmission (4) has a total transmission ratio in a range from 1: 50 to 1:250, wherein the drive drum (5) is designed to be operated in a rotational speed range of 0-200 rpm, wherein the electric working machine (3) and the transmission (4) comprise a common shaft (6) which forms both the drive shaft (7) of the electric working machine (3) and a toothed shaft (7) for the transmission (4), wherein the shaft (6, 7) is mounted by means of at least two bearings (8) and comprises a toothing (14) at the transmission-side end region.

Description

[0001] Compact drive system for a conveyor belt

[0002] The invention relates to a compact drive system for belt conveyor systems, comprising at least one electric working machine, a gearbox and a drive drum connected to a conveyor belt of a belt conveyor system.

[0003] Belt conveyor systems are often used for the continuous transport of bulk materials in open-pit and underground mining. This transport often takes place over long distances of several kilometers on endless conveyor belts driven by a multitude of drive drums. For example, DE847427 A shows such a drive using a drive drum on a deflection pulley. Drive powers of more than 2 MW are known from the prior art; for instance, EP2678254 B1 shows a direct-drive, slow-running electric drive unit with a large electric motor.

[0004] Further information from the prior art includes DE102020117438 A1, which describes an electric drive with an integrated gearbox, as used in (electric) motor vehicles. However, the gearbox used here comprises only a spur gear stage; the larger gear ratios required for driving belt conveyor systems, which are particularly advantageously implemented with planetary gearboxes, are not applicable here.

[0005] Operating smaller, high-speed drives on belt conveyor systems is not known in the prior art, as this requires a larger transmission. Drives used in the prior art operate at a constant speed, with a hydrodynamic coupling and / or a speed-variable device used for starting. Compact, pre-assembled drive systems are advantageous for belt conveyor system installation, enabling rapid assembly. Modular drive systems with smaller electric motors can simplify installation; multiple motors with identical parts and smaller drive components facilitate maintenance and ensure good accessibility for servicing.Small high-speed electric motors, with a rated speed between 5000 rpm and 15000 rpm, and especially with a rated speed in the range of 7500 to 12000 rpm, are advantageous because they are cheaper due to their smaller size for the same power output, but require cooling.

[0006] The object of the invention is to provide a compact, integrated drive device for a belt conveyor system. Furthermore, the object of the invention is to provide a drive device that can be advantageously operated in the harsh conditions of open-pit mining operations, with contamination and vibrations, and that features compact, maintenance-friendly, and automatic cooling and lubrication.

[0007] The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims.

[0008] According to the invention, the problem of a drive system is solved, wherein the electric machine has a rated speed between 5000 rpm and 15000 rpm, wherein the gearbox has an overall transmission ratio in the range of 1:50 to 1:250, and is designed to operate the drive drum in a speed range of 0 to 200 rpm, wherein the electric machine and the gearbox comprise a common shaft that forms both the drive shaft of the electric machine and a toothed shaft for the gearbox, wherein the shaft is supported by at least two bearings and includes a toothed section at the gearbox-side end region, wherein the gearbox comprises a planetary gear set, wherein the shaft of the electric machine forms the sun gear of the planetary gear set, and wherein the gearbox further comprises a spur gear set. An embodiment in which the shaft is supported at only two bearing points is particularly advantageous.It is particularly advantageous if the system consists of a fixed bearing and a floating bearing, as this allows thermal stresses to be balanced while still holding the shaft in a defined axial position.

[0009] The compact design with a common shaft is advantageous because no additional coupling is required, resulting in lower costs and reduced wear. The mechanical connection between the drive and gearbox also allows for the use of a common housing, enabling intrinsically safe operation and a unified drive system. This protects the surrounding environment from rotating parts and reduces the ingress of contaminants, while requiring fewer dynamic seals. The required gear ratio in this power class can be achieved particularly effectively using a planetary gearbox, which, together with a subsequent spur gearbox, enables highly efficient power transmission. This allows smaller electric power tools to be used as the drive, which can deliver high power to the drive drum at higher speeds.The use of smaller, fast-rotating electric machines is also advantageous for precise control of the drives using frequency converters.

[0010] A further advantage is a drive system in which the shaft's toothing in the gearbox-side end region is designed as spur gearing. The gearbox-side end region is the part of the shaft that projects into the gearbox and forms a splined shaft. The toothing on the shaft is advantageously designed as spur gearing, with the teeth and tooth valleys running parallel to the axis of rotation. This allows the shaft to continue engaging with the downstream gearbox during thermal expansion in the direction of the axis of rotation without causing additional stress on the gearbox. Furthermore, no axial forces are transmitted to the bearings or the electric motor.

[0011] A further advantage is a drive system in which the shaft is supported at two points, with a rotor of the electric machine arranged between the two bearings. Supporting the shaft with two rolling bearings is particularly advantageous when the bearings are located on both sides of the rotor. The compact assembly allows the bearings for the gear shaft and motor to be combined. This advantageously reduces the costs for bearings and bearing lubrication. The number of mechanically moving parts in the gearbox can also be advantageously reduced, as a coupling between the motor and gearbox is no longer required.

[0012] A further advantage is a drive system in which one of the bearings supporting the shaft is designed as a fixed bearing, suitable for absorbing axial forces. If the bearing on the side facing away from the gearbox is designed as a fixed bearing, this has the advantage that the bearing cap can be mounted very precisely. Fine adjustment of the axial position is also possible via the bearing cap with this type of bearing arrangement. Particularly for coolant lines, a precise position here can allow for a small distance between the bearing cap and the shaft, which even permits the passage of a coolant line. If the fixed bearing is positioned between the rotor and the gearbox, minimized thermal expansion of the shaft can be advantageously achieved, as it expands on both sides of the fixed bearing.

[0013] It is further advantageous that the gearing is designed to allow the thermal expansion of the shaft without introducing additional axial forces into the shaft bearings. A drive system comprising a cooling system is also advantageous, wherein the cooling system is designed to cool and / or lubricate at least the electric drive motor and the gearbox.

[0014] The cooling system is advantageously arranged and designed to be compact within the drive system, cooling both the electric motor and at least the first gear stage of the connected transmission. It is particularly advantageous for the drive system if all lossy components (motor and transmission) are cooled and lubricated with a single medium. It is especially advantageous that the components can also be cooled when the system is stationary. For this purpose, the cooling system is supplied with at least one separate coolant pump. The cooling system can also have a common oil pan or a common oil tank that can hold all the coolant / oil used when the system is stationary. Preferably, an oil is used as the coolant that can function as both a lubricant and a coolant.This allows for environmentally safe operation of the drive system, and cooling and / or lubrication is independent of the operation of the drive system.

[0015] In current technology, large, slow-rotating drives are typically used. A further advantage of the compact arrangement of the gearbox and smaller electric motor is that the waste heat does not need to be dissipated via convection or fans at the drives, but is instead directed through the cooling system. This means that the heat capacity and thermal conductivity of the components used have less impact on cooling, and more robust housings can be used.

[0016] The cooling medium can be selected as an oil that cools and lubricates the transmission components, as well as the engine and its bearings. By using a cooling and lubrication system with a coolant pump, immersion lubrication is no longer necessary for the transmission. The gears are lubricated and cooled via injection lubrication. This results in an improvement in efficiency compared to the prior art.

[0017] The shared housing of the gearbox and electric drive unit or motor allows for venting and pressure equalization to the environment via a central venting device. Prior art designs often employ multiple venting devices, resulting in higher costs and a greater potential for failure. This increased number of venting devices can also facilitate the ingress of dirt into the housing and / or motor. Furthermore, it is advantageous to implement the venting device within the gearbox to prevent dirt and condensation from accumulating in the motor unit.

[0018] A further advantage is a drive system in which at least one of the bearings supporting the shaft is designed as a rolling bearing with ceramic rolling elements. A ball bearing with ceramic balls is particularly advantageous here. For the high rotational speeds of the shaft, greater than 4000 rpm, a bearing with ceramic balls is especially beneficial because these balls exhibit high hardness and thus less wear. Another advantage of rolling bearings with ceramic rolling elements is that the ceramic is not electrically conductive; electrical insulation and / or targeted grounding of the electric motor rotor can be achieved through the use of these bearings.

[0019] A further advantage is a drive system in which the electric motor and the gearbox are shielded from the environment by a shared housing, which is designed in multiple parts. A compact arrangement of the drive directly on the housing allows for a single housing for the gearbox and electric motor. Since the high-speed motors are significantly smaller, they can be flanged to the housing in such a way as to form a single, integrated housing. Here, all moving parts, except for the gearbox output shaft, are enclosed and can thus be effectively shielded from harsh environments. The shared housing is particularly advantageous because it allows for complete pre-assembly of the drive and gearbox, which significantly simplifies on-site installation on the belt conveyor system.

[0020] A further advantage is a drive system in which electrical potential equalization takes place on the common shaft, preferably by means of a grounding ring. Since the shaft carries both a rotor of the electric motor and forms a gear shaft for the gearbox, it is important that no electrical potential enters the gearbox uncontrollably, as a discharge with sparking could damage the gearbox. The shaft therefore includes a machined surface on which a grounding ring can electrically conduct a potential. In this way, no electrical voltage enters the gearbox or the housing of the drive system.

[0021] A further advantage is a drive system in which the gearbox is designed as a planetary gear set, with the shaft of the electric drive forming the sun gear of the planetary gear set. The use of a planetary gear set is particularly effective and efficient for converting the high speed of the electric drive motor into a lower drive speed, in the range of 30–250 rpm, of the drive drum.

[0022] A further advantage is a drive system in which the drive system housing comprises two to four free shaft ends designed to accommodate a brake and / or a backstop. Particularly when using an additional gear stage, additional mechanical shafts can be extended from the housing as connections to enable a brake for controlled shutdown in the event of a conveyor belt malfunction. A backstop can also prevent the conveyor belt from moving against the conveying direction under the weight of the load in the event of a power failure.

[0023] A further advantage is a drive system in which the drive system housing includes connection points designed to support the drive system via a foundation or transport device. The compact design of the drive system with a housing allows for shared connection points for transport by crane or forklift. For example, three or four crane lifting eyes can be attached to the housing. The connection points can also be designed as flanges or mounting brackets to allow anchoring to a foundation. A further advantage is a drive system in which the electric drive motor is designed as an asynchronous motor, which is designed to operate in a speed range of 5,000 to 15,000 rpm. Small, high-speed asynchronous motors can be used particularly advantageously for the invention.In the prior art, large electric drives with a rated speed of 250–3600 rpm are used for belt conveyor systems, the rated speed depending on the mains frequency and the number of pole pairs. Within the scope of this invention, smaller, high-speed electric motors with a rated speed in the range of 5000–15000 rpm are advantageously used. Electric drive devices with a rated speed of 6000–12000 rpm are particularly advantageous. These high-speed drives are controlled by frequency converters, which enables flexible control of speed and / or torque.

[0024] A further advantage is a drive system in which the gearbox is designed as a planetary gear set, with the first planetary stage having a gear ratio of 1:5 to 1:12.5. Planetary gear sets are particularly advantageous for high input speeds above 5000 rpm, provided the speed is introduced via the sun gear and transmitted via the ring gear or the planet carrier, achieving particularly high efficiency. Depending on the geometry, a planetary gear set can achieve a gear ratio of 1:5 to 1:12.5, with ratios of 1:6 to 1:10 being particularly advantageous. For this type of drive, the planetary gear set offers advantages in terms of power density, acquisition costs, service life, and efficiency.

[0025] If the drive shaft is operated directly as a sun gear, the number of required components is further advantageously reduced, and pre-assembly can be carried out to benefit the system. This reduces the commissioning time on-site at the conveyor belt. A drive system comprising at least two electric drive motors, each connected to a first planetary stage, is also advantageous. The two first planetary stages are then connected together to a further gear stage, thus jointly driving a drive drum. A modular design of the drive system, which can be implemented with either one or two electric drive motors, is advantageous because a smaller number of motor variants can be used within the modular system, resulting in a high degree of parts commonality. At the same time, a modular design is cost-effective because the cooling system and spare parts can supply several drive sizes.It is particularly advantageous to use drive systems with two or more electric drive units on sections of a belt conveyor that have an incline. On sections of the belt conveyor that run over level terrain, drive systems with only one electric drive unit can then be used.

[0026] A further advantage is a drive system in which the gearbox includes an additional gear stage designed as a planetary gear set. This allows for a particularly advantageous reduction in rotational speed following the spur gear set. A medium speed range is especially beneficial for the spur gear set, enabling the connection of various electric machines and / or brakes and / or backstops. The downstream planetary gear set can very effectively provide the low rotational speeds of the drive drum within a range of 0–200 rpm.

[0027] A further advantage is a drive system in which the gearbox and the electric drive motor share a common venting device. Due to the integrated arrangement, where the electric motor engages with the first planetary gearbox, a single venting device can be used. The venting device allows for pressure equalization of the air within the housing, which occurs particularly due to temperature differences. Simultaneously, the venting device prevents the ingress of contaminants and / or water into the housing and / or the drive. In the prior art, each drive and each gearbox stage typically includes its own venting device. The design with a single venting device offers cost savings and simplifies maintenance.

[0028] A further advantage is a drive system in which the shaft exiting the housing and connecting to the drive drum includes a mechanical seal and / or a labyrinth seal with grease lubrication. The housing can advantageously be sealed against the harsh environment to reduce or prevent the ingress of contaminants, particularly into the lubrication and / or coolant circuit.

[0029] A further advantage is a drive system wherein the shaft arranged between the electric drive motor and the planetary gearbox comprises a coupling, in particular a jaw coupling or a highly elastic coupling. A coupling and / or a multi-section shaft can be advantageous for assembling the drive system. Furthermore, a coupling, in particular a highly elastic coupling, can reduce thermal stresses and / or vibrations.

[0030] A further advantage is a drive system comprising a controller and at least one frequency converter, wherein the at least one electric drive is designed to be speed- and / or power-adjustable by means of a frequency converter. Speed ​​and / or power control is particularly advantageous because the power can be adjusted according to the load on the conveyor belt using the frequency converter. This reduces tension in the conveyor belt when the load varies, as the individual drive units provide precisely the required power and do not need to operate at a constant speed along the entire belt length. Furthermore, the controller also advantageously enables smooth starting of the belt conveyor system. The invention is explained below with reference to the figures. The figures show in detail:

[0031] Fig. 1: Overview of belt conveyor system with drive system

[0032] Fig. 2: Drive system

[0033] Fig. 3: electric drive motor

[0034] Fig. 4: Further embodiment of a drive system

[0035] Figure 1 shows a schematic, non-scale overview of a belt conveyor system 2 comprising a drive system 1 with features of the invention. The belt conveyor system 2 shows a conveyor belt loaded with bulk material. The belt is driven by two drive drums 5 and supported by support rollers. Optionally and advantageously, a plurality of drive systems 1 are used to operate the kilometer-long belt conveyor systems 2 in mining and open-pit mining applications. The drive systems 1 can advantageously be controlled by means of a common control system. The electric drive motors are operated directly from a power grid or, advantageously, their power and / or speed are controlled by means of frequency converters. Each drive system is advantageously low-maintenance and robustly shielded against weather and environmental contaminants.A drive system 1 comprises an electric drive motor 3, the power and / or speed of which is optionally and advantageously controlled by a frequency converter. The electric drive motor is connected to a gearbox 4, which in turn drives the conveyor belt via a drive drum 5. The gearbox 4 can advantageously be designed as a multi-stage gearbox 4. Particularly advantageously, the gearbox 4 comprises at least one planetary gearbox. The drive system 1 can also, optionally and advantageously (not shown), comprise two drive motors, which then jointly drive a drive drum via a further gearbox stage. Such a configuration can transmit a greater power to the conveyor belt of the belt conveyor system 2 by means of a plurality of smaller, high-speed drives 3. Figure 2 shows a schematic, non-scale, partial sectional view of a drive system 1 with features of the invention.On the right side of the illustration is an electric drive motor 3, which rotates a shaft 6. The electric drive motor 3 comprises a stator 21, which is arranged in a housing 9. Furthermore, the electric drive motor 3 comprises a rotor, which is arranged on the shaft 6 and rotatably mounted in the housing 9 by means of bearings 8. The housing 9 can enclose both the drive motor 3 and the gearbox 4 and advantageously shield them from the environment. The housing 9 can advantageously and optionally include a common cooling system 10. The cooling system 10 can introduce coolant 11 into both the electric drive motor 3 and the gearbox 4 by means of a coolant pump 13. The coolant 11 can also be used as a lubricant in the gearbox 4 and at the bearings 8, since it is optionally and advantageously an oil. The combination of the electric drive motor 3 and the gearbox 4 can be used to power the drive motor 3 and the gearbox 4.The electric motor 3 and gearbox 4 enable a particularly advantageous compact arrangement. The housing 9 is advantageously constructed in multiple parts, but can be designed as a single assembly that largely encloses the drive system 1. This allows for advantageous pre-assembly, and the drive system 1 can be transported to the installation site as a pre-assembled unit. Cooling via cooling system 10 is particularly advantageous when it is provided jointly for the gearbox 4 and the drive motor 4. For example, only one filter system 4 and one coolant pump 11 are required, and the coolant pump 13 can also be advantageously designed with redundancy. The cooling system 10 comprises a plurality of coolant lines 12 that are arranged on the housing or guided through parts of the drive device by means of bores. The coolant lines 12 are advantageously and optionally insulated from the environment.In shaft 6, rotor 20, and stator 21, the coolant lines 12 are designed so that the coolant flowing within them can absorb heat. The coolant lines advantageously converge in a coolant reservoir. Furthermore, the coolant lines 12 can carry coolant 11 through a heat exchanger to cool the coolant 11 and dissipate the transported heat to the environment. Between housing 9 and shaft 6, the coolant line 12 can have a gap that releases a small amount of coolant 11 as a lubricant to the bearings 8. This advantageously eliminates the need for a seal between shaft 6 and housing 9 while simultaneously providing lubrication to the bearings 8. An earthing ring 23 is arranged on shaft 6 and housing 9, which is electrically connected to shaft 6 at a contact surface 24, thus enabling equipotential bonding 23 between shaft 6 and housing 9.This prevents an electrical potential from the drive motor 3 from being introduced into the gearbox 4. The gearbox 4 comprises a first gear stage, which in the illustrated embodiment is designed as a planetary gear 30. The cooling system 10 comprises, as shown, coolant lines 12 that are routed into the gearbox and optionally and advantageously provide lubrication and / or cooling of the gear teeth and / or bearings 8. In addition to the toothed shaft 7, designed as a sun gear 31, the planetary gear 30 comprises planets 32 and a ring gear 33. The planetary gear 30 can optionally and advantageously be connected to a further gear stage 34 to further reduce the input speed of the electric motor 3. Optionally, and not shown in the illustration, two or more electric drive motors 3 can also jointly drive a drive drum 5 via the further gear stage 34.Smaller, high-speed drives can thus be connected via a further gear stage 34, advantageously each by means of an upstream planetary gearbox 30. This configuration allows for a modular design with several small electric motors 3. The further gear stage 34 can advantageously be designed as a spur gear. The gearbox 4 is connected to the drive drum 5 on the output side, with the belt of a belt conveyor 1 being driven by means of the drive drum 5. An additional coupling device 35 and / or another gear stage 34 can optionally and advantageously be arranged between the gearbox 4 and the drive drum. The coupling device 35 can optionally and advantageously include a highly elastic coupling element, thus damping vibrations and shock loads. Furthermore, the coupling device 35 can also include a hydrodynamic coupling, in order to mechanically relieve stress, particularly during start-up processes.Depending on local conditions, the coupling device may also include a driveshaft and / or a deflection gear in order to allow for free positioning of the drive system's installation position.

[0036] Figure 3 shows a schematic, non-scale partial sectional view of an electric drive machine 3 comprising an electric motor 3 and parts of a cooling system 10 with features of the invention. The electric motor 3 comprises a central shaft 6, which is rotatably mounted at two points by bearings 8. The shaft 6 includes a toothed section at the gear-side end, thus forming a toothed shaft 7 that can engage with a gearbox 4 (not shown) (compare Figure 2). Advantageously, the toothed shaft 7 forms a sun gear 31, which drives a planetary gear set 30 (not shown). The shaft 6 includes a coolant line 12, which is designed to receive coolant 11 through the housing. The housing cover includes a connection for a further coolant line 12 (not shown) which is connected to a coolant pump 13.A small gap can advantageously be formed between the bearing cap and the shaft 6. This gap allows free movement of the shaft 6 and also transfers a small amount of coolant to the bearing as a lubricant. This gap is advantageously 5–500 µm in the axial direction. The coolant 11 is conveyed from the shaft 6 to the interior of the rotor 20 by means of at least one further radially guided coolant line 12. There, it is guided axially outwards to the ends of the rotor 20 via coolant channels, thus cooling the rotor 20. The coolant 11 is carried away by the rapid rotation of the rotor 20 and is prevented by a protective shield 22 from entering the gap between the rotor 20 and the stator 21.The coolant is finally returned to the coolant circuit in the lower part of the housing 9 through at least one opening via a further coolant line 12, advantageously using a heat exchanger to recover the heat absorbed by the electric motor. The stator 21 also has channels through which coolant 11 is guided to enable cooling of the stator 21. The shaft 6 includes a machined contact surface 24 which is electrically conductive and connected to a grounding ring 23 for equipotential bonding. The end of the shaft 6 facing the gearbox 4 (on the left side of Figure 3) is designed as a toothed shaft 7 and advantageously includes straight teeth parallel to the axis of rotation. Thus, the electric drive motor 3 can advantageously directly engage the shaft 6 to form a sun gear 31 in a planetary gear set 30 (not shown).

[0037] Figure 4 shows a further embodiment of the invention as a schematic, non-scale partial sectional view of a drive system 1. The features are largely as described in Figure 2. In contrast to Figure 2, the transmission 4 comprises a planetary gear 33 and a spur gear 37. The spur gear comprises at least two pinions shown, the shafts 6 of which are advantageously and optionally extended from the housing 9. One shaft 6 is optionally and advantageously connected to a backstop 38 and / or a brake 36, which prevents a reversal of the direction of rotation of the shaft 6, the planetary gear 33, and / or the electric drive 3. Furthermore, a second shaft 6 of the spur gear 37 is optionally and advantageously extended from the housing. This second shaft 6 is optionally and advantageously connected to a brake 36 or to another electric drive 3.It is particularly advantageous to integrate a further drive 3 as a drive train with its own planetary gear 30 into the drive device 1 via the spur gear 37. The side on which the electric drives are arranged on the housing shown in Figure 4 is only exemplary; an arrangement with two drives on the same side of the gearbox is also provided for in the invention.

[0038] Reference symbol list

[0039] 1 Drive device

[0040] 2 belt conveyor system

[0041] 3 Electric working machine, drive, electric motor

[0042] 4 gearboxes

[0043] 5 Drive drum

[0044] 6 wave

[0045] 7 Drive shaft, toothed shaft

[0046] 8 bearings

[0047] 9 cases

[0048] 10 Cooling system

[0049] 11 Coolant

[0050] 12 Coolant line

[0051] 13 Coolant pump

[0052] 14 Filter device

[0053] 20 Rotor

[0054] 21 Stator

[0055] 22 Protective shield

[0056] 23 Potential equalization / grounding ring

[0057] 24 contact area

[0058] 30 planetary gears

[0059] 31 Sun wheel

[0060] 32 planets

[0061] 33 Ring gear

[0062] 34 gear stages

[0063] 35 Clutch

[0064] 36 Brake device

[0065] 37 Spur gear units

[0066] 38 Backstop

Claims

Patent claims 1. Drive system (1) for a belt conveyor system (2), comprising at least one electric motor (3), a gearbox (4), and a drive drum (5) connected to a belt of a belt conveyor system (2), characterized in that the electric motor (3) has a rated speed between 5000 rpm and 15000 rpm, wherein the gearbox (4) has an overall gear ratio in the range of 1:50 to 1:250, and is designed to operate the drive drum (5) in a speed range of 0 to 200 rpm, wherein the electric motor (3) and the gearbox (4) comprise a common shaft (6) which forms both the drive shaft (7) of the electric motor (3) and a toothed shaft (7) for the gearbox (4), wherein the shaft (6, 7) is supported by at least two bearings (8), and comprises a toothed section (14) at the gearbox-side end region, wherein the gearbox (4) comprises a planetary gear (30),wherein shaft (6, 7) of the electric working machine (3) forms the sun gear (31) of the planetary gear (30), and wherein the gear (4) further comprises a spur gear (37).

2. Drive system (1 ) according to claim 1 , characterized in that the toothing (14) of the shaft (6, 7) in the gear-side end area is designed as straight toothing (12).

3. Drive system (1) according to claim 1 or claim 2, characterized in that the shaft (6) is supported at two points, wherein a rotor (20) of the electric motor is located between the two bearings (8). The working machine (3) is arranged and one of the bearings (8) is designed as a fixed bearing to be suitable for absorbing axial forces.

4. Drive system (1 ) according to one of the preceding claims, characterized in that the transmission (4) comprises a further transmission stage which is designed as a planetary gear (30).

5. Drive system (1 ) according to one of the preceding claims, characterized in that the drive system (1 ) comprises a cooling system (10), wherein the cooling system (10) is designed to cool and / or lubricate at least the electric drive machine (3) and the gearbox (4).

6. Drive system (1) according to one of the preceding claims, characterized in that the shaft (6, 7) which is arranged between electric drive machine (3) and planetary gear (30) comprises a coupling, in particular a jaw coupling or a highly elastic coupling.

7. Drive system (1) according to one of the preceding claims, characterized in that the electric working machine (3) and the multi-stage transmission (4) are shielded from the environment by means of a common housing (14), wherein the housing (14) is designed in multiple parts.

8. Drive system (1 ) according to one of the preceding claims, characterized in that an electrical potential equalization (23) is carried out on the shaft (6, 7) which is arranged between the electric drive machine (3) and the planetary gear (30), preferably by means of an earthing ring.

9. Drive system (1) according to one of the preceding claims, characterized in that the at least one shaft (6) of the transmission (4) is led out of the housing (9) as free shaft ends, wherein the shaft end is designed to accommodate a braking device (36) and / or a backstop (38).

10. Drive system (1 ) according to one of the preceding claims, characterized in that the housing (9) of the drive system (1 ) comprises a plurality of connection points designed to support the drive system (1 ) over a foundation or a transport device.

11. Drive system (1) according to one of the preceding claims, characterized in that the electric drive machine (3) is designed as an asynchronous motor and is designed to be operated in a nominal speed range of 5 000 - 15 000 rpm.

12. Drive system (1 ) according to one of the preceding claims, characterized in that the transmission (4) is designed as a planetary gear (30), wherein the first planetary stage (30) has a gear ratio of 1 :5 to 1 :12.

5.

13. Drive system (1 ) according to one of the preceding claims, characterized in that the drive system (1 ) comprises two electric drives (3) which are each connected to a first planetary stage (30), wherein the two first planetary stages (30) are connected to a further gear stage (34) and thus jointly drive a drive drum (5).

14. Drive system (1 ) according to one of the preceding claims, characterized in that the gearbox (4) and the electric drive motor (3) have a common venting device.

15. Drive system (1) according to one of the preceding claims, characterized in that the drive system (1) comprises a controller and at least one frequency converter, wherein the at least one electric drives (3) are designed to be adjustable in speed and / or power by means of a frequency converter.

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