DRIVE DEVICE

Description

[0001] The invention relates to a drive device for a machine used in heavy industry, particularly in the raw materials and mining industries. The invention further relates to a machine and the use of a drive device.

[0002] In heavy industry, particularly in the raw materials and mining sectors, machinery characterized by high drive power is used to perform its tasks. Examples of such machinery include bucket-wheel excavators, belt conveyors, crushers, mills, and shaft hoisting systems. Besides high drive power and torque, modern drives must also meet other requirements. These include providing different speeds and torques depending on the machine's needs, distributing loads (e.g., in multi-drive systems), and preventing or limiting peak loads. Furthermore, high demands are placed on reliability and efficiency.

[0003] Conventional drive systems consist of several components, including a frequency converter, electric motor, coupling, gearbox, and possibly another coupling and a brake. However, the probability of drive failure increases with the number of components. For this reason, direct drives are being used more and more frequently in the aforementioned machinery. A direct drive for a belt conveyor system is described, for example, in European Patent Application EP 2 562 102 A1. A direct drive typically consists of only a frequency converter and an electric motor, possibly with the addition of a coupling and a brake. This results in a number of advantages, including improved drive reliability due to the reduced number of components, and lower maintenance requirements.

[0004] Electric motors used in direct drives are typically slow-running synchronous motors. These motors provide the necessary high torque and low speed through direct connection to the driven machine. Such synchronous motors consist of a stator and a rotor. The rotor is mechanically connected to the driven machine. There is no direct mechanical contact between the rotor and the stator; they are separated by an air gap (ranging from 2 mm to 20 mm, depending on the design). If this air gap is not maintained, significant damage to the motor will occur. Because the rotor and stator are mechanically separated, maintaining the air gap requires considerable effort. To ensure the air gap is maintained, the foundations or support structures are exceptionally robust to prevent relative movement between the rotor and stator as much as possible.Additionally, air gap monitoring can be provided to detect changes in a timely manner. If corresponding changes in the air gap are detected, a signal is generated which can lead to the shutdown of the drive.

[0005] The synchronous motors used are generally separately excited, meaning the rotor is supplied with an excitation current via slip rings. The slip rings, especially the brushes for transmitting the excitation current, are wear parts. Their inspection, maintenance, and replacement are carried out as part of system maintenance.

[0006] For mobile or semi-mobile machinery, the weight of the drive unit is a crucial factor. Lighter drive units allow for lighter substructures, resulting in lighter and therefore more cost-effective machinery. Regarding weight, conventional drive units are lighter for the same power output. However, when considering the entire system, the additional effort required to maintain the air gap in the motor usually results in a heavier overall weight.

[0007] Reliability and availability of drive technology is another important criterion for plants in the raw materials and mining industries. The fewer components a drive train contains, the higher its availability.

[0008] To achieve high system availability, operators often keep complete drive components or relevant parts of direct drives in stock as spare parts, so that damaged components can be replaced and / or repaired in the event of a failure. There are also concepts and solutions with multiple drives, where, in the event of a failure, one drive is deactivated and the machine continues to operate at partial power using one or more other drives.

[0009] EP 2 481 701 A1 discloses a lifting mechanism for a container crane. The lifting mechanism comprises at least one cable drum for lifting a load and at least one electric motor driving the cable drum, which may be designed as a segmented motor.

[0010] US 2010 / 083851 A1 discloses an electric drive for generating pivoting or rotational movements. The drive comprises a secondary part with a circular or curved shape and a primary part with at least two straight primary part segments arranged at a predetermined angle to each other according to the shape of the secondary part.

[0011] US 2009 / 051253 A1 discloses an electric machine for driving a cylinder of a printing press. The electric machine has a primary part with primary part segments and a secondary part with secondary part segments.

[0012] DE 2034 307 A1 discloses a drive drum for belt conveyor systems, the drum shell or parts rigidly connected to it are movable relative to arc-shaped curved stationary stator windings of a linear motor.

[0013] US 2003 / 094524 discloses a gearless grinder with a stator having several linear stator sections and a housing on which at least one winding is arranged, spaced apart from the stator by an air gap.

[0014] DE 10 2010 040 724 A1 discloses a method and an arrangement for determining the degree of grinding of a material in a mill. The mill has a drum in which the material is located during the grinding process and which is driven during the grinding process by a magnetic drive with at least one magnetic segment.

[0015] EP 2 562 102 A1 discloses a belt conveyor system and a method for its operation and use. The belt conveyor system for heavy industry, in particular for the raw materials or mining industry, comprises at least one supporting structure, a conveyor belt, and at least one drive device for driving the conveyor belt, wherein the drive device comprises at least one drive shaft, at least one drive shaft bearing assembly, at least one drive roller, and at least one separately excited drive motor in the form of a frequency converter-fed AC synchronous motor with a stator and a rotor. The drive shaft and the at least one drive motor are connected to each other without a gear system, with a coaxial arrangement of rotor and drive shaft, each drive shaft being guided through at least one rotor.

[0016] From US Patent 2013 / 0306773 A1, a tube mill is known, wherein the tube mill has a body rotatably arranged about a rotational axis, wherein material to be ground can be introduced into the body for comminution, wherein the tube mill has an electric motor for rotating the body, the electric motor having a rotor arranged around the body and non-rotatably connected to the body, and a stator yoke arranged stationary around the rotor. The tube mill has a concrete element circulating around at least half the circumference of the stator yoke, wherein the stator yoke is connected to the concrete element in such a way that forces acting on the stator yoke are transmitted to the concrete element.

[0017] EP 1 446 858 B1 discloses a brushless permanent magnet motor with a ring-shaped rotor and a modular stator, the segments of which are each magnetically insulated. Each stator segment has its own control and power electronics module, which is located inside the stator and optionally has a separate power source.

[0018] The invention is based on the objective of providing a drive device with high operational reliability. The invention is further based on the objective of providing a working machine with high reliability.

[0019] The first problem is solved according to the invention by a drive device for a machine for heavy industry, in particular for the raw materials and mining industries, comprising a permanent magnet excited motor, wherein the motor has a rotor and a stator, and wherein the motor is a segmented motor in which the rotor and the stator are composed of several segments, and wherein the segments of the stator can be individually supplied with electric current by the frequency converter, wherein the rotor and the stator are mounted on a common bearing element, wherein control of the individual motor segments allows the operation of the motor in partial load ranges, wherein the rotor forms an annular, circumferentially extending, axially open gap, which is bounded axially by a rotor wall and radially by a radially inner annular rotor wall and a radially outer annular rotor wall.wherein the stator is arranged in the gap such that the rotor segments arranged on the radially inner rotor wall are assigned to the stator segments opposite it, wherein a seal is provided between the radially outer rotor wall and the stator, which protects the air gap formed in the area between the rotor segments and the stator segments from the ingress of contaminants.

[0020] The invention is based on the idea of ​​significantly improving motor availability through its segmented design, thereby also increasing the reliability of the drive device. Thanks to its modular construction and interchangeability, maximum installation flexibility is achieved. Further advantages of a segmented motor include easier handling and assembly, as well as good torque scalability.

[0021] The segments comprise, in particular, both stator and rotor segments, which, when assembled accordingly, form a permanent magnet synchronous motor. The motor segments are integrated into or onto the respective machine. The permanent magnet design eliminates the need for slip rings and brushes, thereby reducing maintenance and spare parts costs. The rotor segments, also referred to as rotor segments, are formed by permanent magnets. Only the stator segments, also referred to as stator segments, are wired.

[0022] According to the invention, the rotor and the stator are mounted on a common bearing element. This bearing element is a rotating shaft or axle. This type of mounting prevents relative movement between the rotor and the stator, thus maintaining the required air gap. A support structure for the rotor and a support structure for the stator are designed such that rotation of the rotor is permitted during operation of the machine, while the stator remains stationary.

[0023] According to the invention, the drive device further comprises a frequency converter, wherein the stator segments can be individually supplied with electrical current by the frequency converter. The frequency converter allows the motor to be controlled and regulated according to the requirements of the respective machine. The separate power supply of the stator segments ensures particularly high flexibility and virtually trouble-free operation of the machine, because if a stator segment fails, the machine can continue to be driven at reduced power. Controlling the individual motor segments also allows the motor to operate in partial load ranges, for example, if a segment fails or the machine requires less drive power. This contributes to increasing the availability of the drive and allows for a very flexible response to the requirements of the machine.For example, if no rated power is required, operation can continue at a lower power level. For this purpose, individual stator segments are switched off. This saves energy and reduces electricity costs.

[0024] Preferably, the rotor segments are arranged in a circle. The shape of the rotor is optimally adapted to the bearing element, which is designed in particular as a shaft or axle. The number of rotor segments is determined by the number of permanent magnets, which in turn depends on the power output. Depending on the size or required power of the motor, the number of rotor segments is in the high double digits or triple digits.

[0025] Preferably, the stator segments are assembled into a semicircular stator. The number of stator segments depends on the power output. The stator segments are particularly larger than the rotor segments, thus requiring fewer stator segments. These are arranged around the rotor, forming a semicircle or arc. With a very high number of stator segments, they can also form a closed circle around the rotor.

[0026] For ease of assembly or replacement, the rotor and / or stator segments are preferably attached to the motor's support structure via a detachable connection. For example, the segments are bolted to the support structure. However, other types of detachable, force-fit or form-fit connections are also conceivable.

[0027] According to a preferred embodiment, the bearing element is a rotatable shaft, the rotor is mounted on the shaft to rotate, and the stator is fixed to the shaft in a stationary position. In particular, the segmented motor is integrated into a rotating part of the machine via the rotor.

[0028] According to an alternative, preferred embodiment, the bearing element is a stationary axis, the rotor is rotatably mounted on the axis, and the stator is fixedly arranged on the axis.

[0029] Advantageously, the motor is designed for operation up to 150 rpm, and particularly up to 100 rpm. The motor, which is primarily a synchronous motor, is therefore ideally suited for use in a direct drive system where the drive unit is integrated into the machine being driven.

[0030] The further problem is solved according to the invention by a working machine for heavy industry, in particular for the raw materials and mining industry, comprising such a drive device.

[0031] The further problem is finally solved according to the invention by using such a drive device as a direct drive in a machine for heavy industry, in particular for the raw materials and mining industry.

[0032] Preferably, the drive device is designed as a direct drive. Direct drive, in this context, refers to a gearless drive in which there are no components between the drive motor and a drive shaft that translate the rotor speed into a different drive shaft speed. The drive shaft thus rotates at the same speed as that dictated by the rotor(s), if there are multiple rotors. Generally, a slow-running synchronous motor (with a speed in the two-digit or lower three-digit range of revolutions per minute) is used for direct drive applications, providing the driven machine with high torque and low speed. Significant weight savings are achieved by integrating the drive device directly into or onto the driven machine. Separate motor housings, motor bearings, and shafts can be omitted, as the segments are integrated into or onto the drive unit.are integrated into the work machine.

[0033] The machine is suitably designed as a bucket wheel excavator, belt conveyor, crusher, mill, or shaft conveyor. However, the use of a direct drive with a segmented motor is not limited to the applications mentioned above; other electrically driven machines are also suitable for the intended use in the raw materials and mining industries.

[0034] An exemplary embodiment is explained in more detail with the aid of a drawing. This schematically illustrates: FIG 1 a longitudinal section through a first embodiment of a drive device, FIG 2 a longitudinal section through a second embodiment of a drive device, and FIG 3 a longitudinal section through a drive drum of a belt conveyor.

[0035] The same reference symbols have the same meaning in the figures.

[0036] In FIG 1 und FIG 2 Figure 2 shows a drive device for application in the mining industry (e.g., in a bucket wheel excavator, a mill, a crusher, a belt conveyor, etc.). The drive device 2 comprises a segmented motor 4 and a frequency converter 6, which is represented symbolically.

[0037] FIG 1 Figure 1 shows a first embodiment of the drive device, in which a rotor 10 of the segmented motor 4, comprising several segments 12, is mounted on a rotatable shaft 8. The shaft 8 is supported at its end by a bearing 14. A stator 16, comprising several stator segments 18, is also mounted on the shaft 8, but in a stationary position. The segments 18 of the stator 16 are individually supplied with electrical current by the frequency converter 6.

[0038] In the illustrated embodiment, the segments 12 of the rotor 10, hereinafter referred to as rotor segments, are arranged circularly around the shaft 8. The segments 18 of the stator 16, hereinafter also referred to as stator segments, can also form a circle, but are in particular arranged in an arc-shaped or semicircular formation, which is not shown in detail here.

[0039] The number of rotor segments (12) and the number of stator segments (18) differ because the segments (12) and (18) are of different sizes. For example, a bucket wheel excavator typically has slightly over 100 rotor segments (12), while the number of stator segments (18) varies between 12 and 16, depending on the engine power.

[0040] The rotor 10 and the stator 16 are not mechanically connected, i.e., there is no direct contact. Instead, an air gap 20 is formed between the rotor segments 12 and the stator segments 18, which, depending on the size of the segmented motor 4 and the application, is, for example, between 2 mm and 20 mm. A seal 22 is also provided between the rotor 10 and the stator 16 to protect against contamination.

[0041] Out of FIG 2 A second embodiment of the drive device is shown, in which the rotor 10 with the rotor segments 12 is arranged on a stationary axis 24. The rotation of the rotor 10 on the stationary axis 24 is enabled by a bearing 26. In this embodiment, the rotor 10 is directly connected to the respective driven machine. The rotor 10 is part of a driven machine (not shown here), i.e., the entire segmented motor 4 is integrated into the driven machine. The segmented motor 4 and the driven machine are arranged on the same axis, so that the drive device 2 drives the driven machine in the manner of a direct drive.

[0042] There are basically two ways to connect to a working machine (e.g. belt conveyor, bucket wheel, crusher, shaft conveyor system): a) The rotor 10 or the stator 16 is a component of the working machine. This case is illustrated by the example of a drive drum 30 for a belt conveyor in the context of FIG 3 explained in more detail. b) The working machine is separately mounted on the shaft 8 or the axle 24, however, the working machine and the drive device 2 share the same shaft 8 or axle 24 (not shown here).

[0043] In FIG 3 A direct drive is shown. As working machine 28, according to FIG 3 A belt conveyor is provided, which has a drive drum 30. The drive drum 30 is mechanically connected to the segment motor 4 in the area of ​​the rotor 10; thus, the rotor 10 is an integral part of the drive drum 30. The common shaft 8 is mounted in bearings 32a and 32b and connected via bearings 32a and 32b to a substructure 34 (steel structure or foundation).

[0044] Similarly, the segment motor 4 can be integrated into other applications in the mining industry, e.g. in bucket wheel excavators, mills, crushers, etc.

Claims

1. Drive device (2) for a work machine for heavy industry, in particular for the extractive and mining industries, comprising a permanent-magnet motor (4) and a frequency converter (6), wherein the motor (4) has a rotor (10) and a stator (16), the motor (4) being a segment motor, in which the rotor (10) and the stator (16) are composed of a plurality of segments (12, 18), and the segments (18) of the stator (16) being able to be individually supplied with electrical current by the frequency converter (6), wherein the rotor (10) and the stator (16) are mounted on a common bearing element (8, 24), with activation of the individual motor segments allowing the operation of the motor in partial load ranges, wherein the rotor (10) forms an annular, axially open gap which extends in the circumferential direction and is delimited axially by a rotor wall and radially by a radially internal annular rotor wall and a radially external annular rotor wall, wherein the stator is arranged in the gap in such a way that the rotor segments arranged on the radially internal rotor wall are assigned to the opposite stator segments there, wherein a seal (22) is provided between the radially external rotor wall and the stator (16), the seal protecting the air gap formed in the region between the rotor segments and the stator segments from the ingress of impurities.

2. Drive device (2) according to Claim 1, wherein the bearing element (8, 24) is a rotatable shaft (8), the rotor (10) is mounted rotationally on the shaft (8) and the stator (16) is fastened in a stationary manner on the shaft (8).

3. Drive device (2) according to either of the preceding claims, wherein the bearing element (8, 24) is a fixed axle (24), the rotor (10) is mounted rotatably on the axle (24), and the stator (16) is arranged in a stationary manner on the axle (24).

4. Drive device (2) according to any one of the preceding claims, wherein the segments (12) of the rotor (10) are arranged in a circle.

5. Drive device (2) according to any one of the preceding claims, wherein the segments (18) of the stator (16) are assembled to form a partially circular stator (16).

6. Drive device (2) according to any one of the preceding claims, wherein the segments (12, 18) of the rotor (10) and / or of the stator (16) are fastened to a supporting structure of the motor (4) via a releasable connection.

7. Drive device (2) according to any one of the preceding claims, wherein the motor is provided for operation up to 150 1 / min, in particular up to 100 1 / min.

8. Work machine (28) for heavy industry, in particular for the extractive and mining industries, comprising a drive device (2) according to any one of the preceding claims.

9. Work machine (28) according to Claim 8, wherein the drive device (2) is designed as a direct drive.

10. Work machine (28) according to Claim 7 or 8, which is designed as a bucket wheel excavator, a belt conveyor (28), a crusher, a mill or a shaft hoisting system.

11. Use of a drive device (2) according to any one of Claims 1 to 6 as a direct drive in a work machine (28) for heavy industry, in particular for the extractive and mining industries.