Gearless conveyor drives

Abstract

A gearless conveyor drive for driving a conveyor belt of a conveyor system is described. The gearless conveyor drive includes a rotor assembly comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt, and a rotor core (8) mechanically mounted to a radially inner surface (4b) of the barrel (4). A plurality of axially-extending passages (18) is provided between the radially inner surface (4b) of the barrel (4) and a radially outer surface (8b) of the rotor core (8) and adapted to receive cooling air for cooling the rotor assembly (2).

Description

[0001] TITLE

[0002] Gearless conveyor drives

[0003] DESCRIPTION

[0004] Technical Field

[0005] The present invention relates to gearless conveyor drives, and in particular to drives that are configured as a large-diameter, low-speed synchronous electric motor adapted to drive a conveyor belt of a conveyor system.

[0006] The conveyor system may be an overland or underground conveyor system and may be used in a mining environment to transport ore from a mine to a processing plant, for example.

[0007] Background Art

[0008] In a known gearless conveyor drive a large-diameter, low-speed synchronous electric motor has a rotating shaft that is connected directly to a separate drive pulley that drives a conveyor belt of a conveyor system. The conveyor belt is looped around the radially outer surface of the drive pulley. The rotating shaft of the gearless conveyor drive may be connected to the drive pulley by a flange connection.

[0009] Summary of the invention

[0010] The present invention provides an improved gearless conveyor drive for driving a conveyor belt of a conveyor system.

[0011] The gearless conveyor drive may include a rotor assembly and a stator assembly, and may be configured as a large-diameter, low-speed synchronous electric motor.

[0012] Improved cooling of the rotor assembly

[0013] In a first aspect of the present invention, the gearless conveyor drive comprises a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt, and a rotor core mechanically mounted to a radially inner surface of the barrel, wherein a plurality of axially-extending passages is provided between the radially inner surface of the barrel and a radially outer surface of the rotor core and adapted to receive cooling air for cooling the rotor assembly.

[0014] Instead of the rotor assembly driving a separate drive pulley, the rotor assembly is arranged radially outside a stator assembly of the gearless conveyor drive and the conveyor belt is looped around the barrel of the rotor assembly. The resulting gearless conveyor drive is physically compact. Rotation of the rotor assembly relative to the stationary parts of the gearless conveyor drive (e.g., the stator assembly and any fixed support structures) will therefore drive the conveyor belt.

[0015] The axially-extending passages between the rotor core and the barrel may extend from one axial end of the rotor core to the other axial end - i.e., along the axial direction of the rotor assembly.

[0016] The barrel may comprise a rigid structural tube that may be made of a suitable metal or metal alloy (e.g., steel, stainless steel or aluminium) and functions as the main structural part of the barrel. The radially inner surface of the tube may be substantially cylindrical and may define the radially inner surface of the barrel. The radially outer surface of the tube may be substantially cylindrical. The radially outer surface of the barrel - i.e., the surface that contacts the conveyor belt - may be defined by the radially outer surface of the tube or by an outer layer that is adhered to the radially outer surface of the tube. The outer layer may be made of a suitable material (e.g., rubber) and may be adhered to the radially outer surface of the tube by a suitable adhesive. The outer layer may protect the underlying tube from wear and tear. The outer surface of the outer layer may be formed with a textured surface such as a diamond or square texture, for example, which may help to increase friction between the conveyor belt and the barrel and reduce slippage. If there is no need for a protective outer layer, this results in reduced material costs and assembly time.

[0017] The passages between the rotor core and the barrel are adapted to receive cooling air for improved cooling of the rotor assembly. In particular, the improved cooling means that less heat is transferred from the radially inner rotor core to the barrel when the gearless conveyor drive is operating. If the barrel of the rotor assembly comprises the optional protective outer layer, this may help to reduce the transfer of heat to the outer layer, thereby extending the lifetime of both the outer layer and the adhesive.

[0018] The improved cooling increases the power density of the gearless conveyor drive.

[0019] Providing passages between the rotor core and the barrel also minimises the transfer of magnetic flux to the barrel. This may be particularly beneficial if the conveyor belt is used to transport ferrous ores, for example, by reducing the number of ore particles that are magnetically attracted to the outer surface of the barrel.

[0020] Preferably, the radially inner surface of the barrel and the radially outer surface of the rotor core are separated almost entirely by the passages - in other words, the passages preferably define an almost continuous annular void between the barrel and the rotor core that is interrupted only by the rotor core mounting members described below. Put another way, the passages as a whole will preferably extend circumferentially along the majority of the radially inner surface of the barrel and the radially outer surface of the rotor core so that the transfer of heat and / or magnetic flux to the barrel is minimised as much as possible.

[0021] The passages may be circumferentially-spaced around the radially outer surface of the rotor core.

[0022] The rotor core may be mechanically mounted to the barrel by a plurality of circumferentially-spaced mounting members. The mounting members are located radially between the barrel and the rotor core. Each passage may be defined between an adjacent pair of mounting members.

[0023] Each mounting member may be fixedly connected to, or integral with, the radially inner surface of the barrel. For example, the mounting members may be formed as separate components such as individual support bars that are fixedly connected to the radially inner surface of the barrel (e.g., to the rigid structural tube) by one or more mechanical fixing such as bolts, or the mounting members may be integrally formed as part of the barrel (e.g., as part of the rigid structural tube). In this case, the mounting members may be formed from the same material as the tube, e.g., a metal or metal alloy such as steel, stainless steel or aluminium, for example.

[0024] Each mounting member may extend axially along the radially inner surface of the barrel (e.g., along the radially inner cylindrical surface of the rigid structural tube). The mounting members may be spaced equally or substantially equally around the radially inner surface of the barrel.

[0025] The rotor core may be substantially tubular and may have a substantially cylindrical radially inner and outer surfaces. The rotor core may comprise a plurality of segments - i.e., the rotor core may be segmented. Each rotor core segment may be mechanically mounted to the barrel (e.g., to the rigid structural tube) by one or more of the mounting members. Each rotor core segment may have a first arcuate surface. The rotor core segments may be arranged circumferentially around the radially inner surface of the barrel so that their respective first arcuate surfaces define a substantially cylindrical radially inner surface of the rotor core that faces radially inwardly towards a stator assembly of the gearless conveyor drive. The rotor core segments may also have a second arcuate surface, opposite the first arcuate surface, so that their respective second arcuate surfaces define a substantially cylindrical radially outer surface of the rotor core that faces radially outwardly towards the barrel. Circumferentially-adjacent rotor core segments may abut each other - i.e., their facing axially -extending edges may be in contact with each other - or they may be spaced apart in the circumferential direction by a small gap.

[0026] Each mounting member may have an engagement profile and the radially outer surface of the rotor core or the second arcuate surface of each rotor core segment may have a corresponding engagement profile such that the rotor core or the individual rotor core segments are removably mounted to the barrel by the mounting members. For example, each mounting member may have a dovetail or T-shaped profile and the radially outer surface of the rotor core or the second arcuate surface of each rotor core segment may have a corresponding dovetail or T-shaped profile.

[0027] In one arrangement, each mounting member may have or define a radially-extending protrusion with an engagement profile. The protrusion may extend axially along substantially the full length of the mounting member. The second arcuate surface of each rotor core segment may have one or more recesses with a corresponding engagement profile, where each recess receives the protrusion of a respective mounting member. Each recess may extend radially into the second arcuate surface and may extend axially along substantially the full length of each rotor core segment. In another arrangement, each mounting member may have a recess with an engagement profile. The recess may extend radially into the radially inner surface of the mounting member and may extend along substantially the full length of the mounting member. The second arcuate surface of each rotor core segment may have one or more radially-extending protrusions, where each protrusion is received in the recess of a respective mounting member. Each protrusion may extend axially along substantially the full length of the rotor core segment. A rotor core segment may be mounted to two or more mounting members - i.e., its second arcuate surface may comprise two or more protrusions or recesses. Two circumferentially-adjacent rotor core segments may be at least partly mounted to the barrel using the same mounting member if it is positioned where the two rotor core segments abut or meet in the circumferential direction. A mounting member may be located at the centre of the second arcuate surface of one or more of the rotor core segments and / or at one or both edges of the second arcuate surface of one or more of the rotor core segments, for example. Each protrusion and its corresponding recess are designed to permit the rotor core segments to move axially relative to the barrel during an assembly process with each protrusion received in its corresponding recess, but to restrict movement of each rotor core segment in the radial and circumferential directions. Similar protrusions and corresponding recesses on the mounting members and the radially outer surface of a non-segmented rotor core would allow the rotor core to move axially relative to the barrel during an assembly process with each protrusion received in its corresponding recess. The rotor core may also be an interference fit on the mounting members. In this case, the rotor core is typically not segmented and is inserted into the barrel axially during an assembly process so that its radially outer surface is supported by the mounting members.

[0028] The mounting members may be made of a non-magnetic material (e.g., stainless steel).

[0029] The rotor core may have any suitable construction. The rotor core may be a bonded core, a solid core or a laminated core, for example. If the rotor core has a laminated construction, the rotor core, or the individual rotor core segments if the rotor core is segmented, may be formed from a stack of thin lamination sheets that are stamped or cut to have an outer profile. The lamination sheets may optionally be made of electrical grade steel with an insulating coating. The lamination sheets are stacked together in the axial direction.

[0030] The rotor assembly may further comprise a plurality of circumferentially-spaced permanent magnet modules on the radially inner surface of the rotor core. The gearless conveyor drive may therefore be a permanent magnet motor (PMM). Each permanent magnet module may comprise one or more blocks of permanent magnet material. Each permanent magnet module may be permanently or removably mounted to the radially inner surface of the rotor core by any suitable mounting means. The plurality of permanent magnet modules is arranged circumferentially around the radially inner surface of the rotor core to define a plurality of rotor poles of alternating polarity. If the rotor core is a segmented rotor core, each rotor core segment may comprise one or more permanent magnet modules on its first arcuate surface that faces towards the stator assembly. The permanent magnet modules are normally spaced apart from a radially outer surface of the stator assembly by an annular air gap.

[0031] The rotor assembly may further comprise a pair of end plates. The end plates may be designed to close the axial ends of the barrel. The end plates may be made of a suitable metal or metal alloy (e.g., steel or aluminium). Each end plate may be located at an axial end of the barrel and is adapted to rotatably mount the rotor assembly. Each end plate may be removably mounted to the barrel, e.g., to the rigid structural tube. In particular, the radially outer part of each end plate may be removably mounted to the respective axial end of the rigid structural tube using one or more mechanical fixings such as bolts so that each end plate may be removed if necessary, e.g., to provide access to the interior of the barrel for maintenance or repair. A radially-extending flange may be provided at both axial ends of the rigid structural tube. Each flange may comprise a plurality of circumferentially-spaced fixing openings. A plurality of circumferentially- spaced fixing openings may be provided in the radially outer part of each end plate - the respective fixing openings in each end plate and each tube flange being aligned to receive the mechanical fixings to removably mount each end plate to the rigid structural tube. The rotor core may be positioned in the space defined by the barrel and the end plates. The radially inner part of each end plate may also be mounted to a stationary part of the gearless conveyor drive (e.g., to a stationary support shaft of the stator assembly) by a respective bearing assembly. The rotor assembly comprising the barrel, the rotor core and the end plates may therefore rotate relative to the stationary part of the gearless conveyor drive when electrical power is supplied to the stator assembly to operate the gearless conveyor drive.

[0032] Cooling air may be circulated through the passages between the rotor core and the barrel by a fan or blower, for example. The fan or blower may be an external fan or blower - i.e., a fan or blower that is external to the rotor assembly. Alternatively, at least one of the end plates may comprise one or more fan blades on its inner surface, which is the surface that faces towards the rotor core. The fan blades are adapted to move cooling air through the passages when the rotor assembly is rotating. One or more fan blades may be provided on both of the end plates. If fan blades are provided on only one of the end plates, cooling air preferably flows through the passages from one axial end of the rotor core to the other axial end - i.e., in one direction through the rotor assembly. In particular, the cooling air will flow from the axial end of the rotor core that faces the fan blades to the other axial end of the rotor core. If fan blades are provided on both of the end plates, cooling air preferably flows through the passages from one axial end of the rotor core towards the middle of the rotor core and from the other axial end of the rotor core towards the middle of the rotor core - i.e., in opposite directions through the rotor assembly. At an intermediate location between the axial ends of the rotor core, typically at or near the middle of the rotor core in the axial direction, the cooling air may flow radially inwardly through one or more radially-extending passages in the rotor core, and may then flow axially through the annular air gap between the rotor assembly and the stator assembly back towards the axial ends of the rotor core. Cooling air may therefore be circulated around the rotor assembly in a closed-loop air cooling circuit that comprises the passages between the rotor core and the barrel, the one or more radially -extending passage in the rotor core, and the annular air gap between the rotor assembly and the stator assembly. Cooling air may also flow through the passages from one axial end of the rotor core to the other axial end if fan blades are provided on both of the end plates - e.g., if the fan blades on one of the end plates are arranged to “push” the cooling air towards the other end plate, and the fan blades on the other end plate are arranged to “pull” the cooling air towards it. The cooling air will therefore flow in one direction through the rotor assembly.

[0033] Each mounting member mentioned above - e.g., the individual support bars that are fixedly connected to the radially inner surface of the barrel (e.g., to the rigid structural tube) by one or more mechanical fixing such as bolts - may extend past the axial end of the rotor core facing the fan blades and may extend so far as to overlap with the one or more fan blades in the axial direction. If fan blades are formed on both of the end plates, each mounting member may extend past both axial ends of the rotor core and may extend so far as to overlap with both sets of fan blades. Each mounting member may extend close to the inner surface of each end plate. Using such extended mounting members has been found to improve cooling by creating turbulent flow of the cooling air through the passages.

[0034] The one or more fan blades may also be used to circulate cooling air around the stator assembly as described in more detail below.

[0035] The gearless conveyor drive may also comprise one or more of the other features described below - e.g., those features that relate to the improved cooling of the stator assembly, the brake disc, and that allow for unobstructed removal of one or more of the stator pole modules.

[0036] The present invention further provides a method of cooling the gearless conveyor drive described above, the method comprising passing cooling air through the axially- extending passages to cool the rotor assembly.

[0037] Improved cooling of the stator assembly

[0038] According to a second aspect of the present invention, the gearless conveyor drive comprises: a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt; and a stator assembly radially inside the rotor assembly, the stator assembly comprising a substantially tubular stator pole carrier and a plurality of stator pole modules that are removably mounted to the stator pole carrier, wherein the stator pole carrier comprises a plurality of axially-extending passages, each passage extending between an inlet opening and an outlet opening, and wherein the inlet and outlet openings are fluidly connected by a plurality of pipes such that the passages and the pipes define one or more liquid cooling circuits adapted to receive cooling liquid for cooling the stator assembly.

[0039] The rotor assembly may be constructed generally as described above.

[0040] The rotor assembly may further comprise a pair of end plates, each end plate being located at an axial end of the barrel and adapted to rotatably mount the rotor assembly as described in more detail above. At least one of the end plates comprises one or more fan blades on its inner surface, which is on the surface that faces towards the rotor core of the rotor assembly. The fan blades are adapted to move cooling air through one or more air cooling circuits for cooling the stator assembly. Cooling air may also be circulated through the one or more air cooling circuits by an external fan or blower, for example. The stator assembly may therefore be cooled by two separate cooling circuits, namely the one or more liquid cooling circuits that are adapted to receive cooling liquid (e.g., water) and the one or more air cooling circuits. The air cooling circuits are described in more detail below. Some level of cooling may therefore be maintained by the air cooling circuit(s) even if there is a fault with the liquid cooling circuit(s), for example.

[0041] The stator pole carrier may be made of a suitable metal or metal alloy (e.g., steel or aluminium). The passages for the cooling liquid may be formed as bores in the body of the stator pole carrier, for example. Such bores may be accurately machined and minimise leakage of cooling liquid into the body of the stator pole carrier. Because the cooling liquid flows directly through the stator pole carrier, there is improved transfer of heat from the stator coils to the cooling liquid.

[0042] Each stator pole module may have an engagement profile and the radially outer surface of the stator pole carrier may have a plurality of circumferentially-spaced corresponding engagement profiles. Each stator pole module is removably mounted to the stator pole carrier by the respective engagement profiles. For example, each stator pole module may have a dovetail or T-shaped profile and the radially outer surface of the substantially tubular stator pole carrier may have a plurality of corresponding dovetail or T-shaped profiles in its radially outer surface. The passages in the stator pole carrier for the cooling liquid may be alternated with the engagement profiles formed in the radially outer surface of the stator pole carrier. For example, if the stator pole carrier includes a plurality of recesses with dovetail or T-shaped profiles, the passages for the cooling liquid may be formed in the parts of the body of the stator pole carrier that are located between the recesses.

[0043] In one arrangement, each stator pole module may have a radially-extending protrusion with an engagement profile. The protrusion may extend axially along substantially the full length of the stator pole module. The stator pole carrier may have a plurality of recesses with a corresponding engagement profile, where each recess receives the protrusion of a respective stator pole module. Each recess may extend radially into the radially outer surface of the stator pole carrier and may extend axially along substantially the full length of the stator pole carrier. In another arrangement, each stator pole module may have a recess with an engagement profile. The recess may extend radially into the stator pole module and may extend along substantially the full length of the stator pole module. The radially outer surface of stator pole carrier may have a plurality of radially-extending protrusions, where each protrusion is received in the recess of a respective stator pole module. Each protrusion may extend axially along substantially the full length of the stator pole carrier. Each protrusion and its corresponding recess are designed to permit the stator pole modules to move axially relative to the stator pole carrier during an assembly process with each protrusion received in its corresponding recess, but to restrict movement of each stator pole module in the radial and circumferential directions. This also allows each stator pole module to be removed from the stator pole carrier in the axial direction if necessary, e.g., if a particular stator pole module is faulty and needs to be replaced. How a faulty stator pole module may be removed from the stator pole carrier is described in more detail below.

[0044] The stator pole modules are normally spaced apart from a radially inner surface of the rotor assembly - e.g., from the permanent magnet modules - by an annular air gap.

[0045] Each removable stator pole module may comprise a stator coil. When the stator pole modules are mounted to the stator pole carrier, the stator coils will be electrically interconnected to define a stator winding of the stator assembly, e.g., a three-phase stator winding. The ends of the stator winding may be electrically connected to a variable speed drive, for example, for supplying power to the stator winding to operate the gearless conveyor drive. The variable speed drive may be electrically connected to a power network or grid, for example, and may be used to control the rotational speed and / or torque of the gearless conveyor drive in a known manner.

[0046] Each stator pole module may comprise an axially-extending passage that extends from one axial end of the stator pole module to the other axial end and is adapted to receive cooling air for directly cooling the stator pole module. The passage may be formed in a body of each stator pole module that supports the stator coil and which may be positioned adjacent to the stator pole carrier - i.e., in a radially inner part of each stator pole module that removably mounts the stator pole module to the stator pole carrier. A radially -extending passage may be formed in the body of each stator pole module to allow cooling air to flow from one axial end of the body towards the middle of the body and from the other axial end of the body towards the middle of the body - i.e., in opposite directions through the body. The radially-extending passage may be located at an intermediate location between the axial ends of each body, typically at or near the middle of each body in the axial direction. The radially-extending passage in the body of each stator pole module may be aligned with a radially-extending passage in the stator pole carrier or with an axial gap between two parts of the stator pole carrier, for example.

[0047] The axially-extending passages in the stator pole carrier are fluidly connected together by the plurality of external pipes to define the one or more liquid cooling circuits. For example, the stator assembly may have a plurality of liquid cooling circuits that are fluidly connected in parallel between a common circuit inlet and outlet or one or more zig-zag or serpentine liquid cooling circuits where the cooling liquid flows through the stator pole carrier in two directions. A plurality of such zig-zag or serpentine liquid cooling circuits may be fluidly connected in parallel between a common circuit inlet and outlet. In general terms, the one or more liquid cooling circuits may have one or more cooling circuit inlets fluidly connected to a source of cooling liquid and one or more cooling circuit outlets fluidly connected to a drain of cooling liquid. In the case of a closed-loop liquid cooling circuit, the one or more cooling circuit outlets may be fluidly connected to the one or more cooling circuit inlets for re-circulation of the cooling liquid. The one or more cooling circuits may comprise one or more heat exchangers for removing heat from the cooling liquid and one or more pumps for circulating the cooling liquid, for example. The heat exchanger(s) and pump(s) may be external to the gearless conveyor drive.

[0048] The inlet and outlet openings between which each passage extends may be formed in the annular end surfaces of the stator pole carrier. An annular end surface of the stator pole carrier may comprise only inlet openings, only outlet openings, or a mixture of inlet and outlet openings depending on the particular arrangement of the one or more liquid cooling circuits. At least some of the pipes may be substantially U-shaped and may fluidly connect the outlet opening of one of the passages with the inlet opening of another passage. Other pipes may fluidly connect the inlet opening of one or more of the passages with a cooling circuit inlet while other pipes may fluidly connect the outlet opening of one or more of the passages with a cooling circuit outlet. The pipes are preferably arranged so that they do not obstruct the insertion or removal of the stator pole modules. More particularly, the stator pole modules may be inserted into, or removed from, the stator pole carrier without having to make any adjustment or modification to the one or more liquid cooling circuits. The pipes may be bent radially inwardly away from the radially outer surface of the stator pole carrier.

[0049] The pipes may be fixedly connected to the stator pole carrier, e.g., by welding, bonding or fitting them to the body of the stator pole carrier. This allows for easy detection of the leakage of the cooling liquid by visually inspecting the weld sites at the axial ends of the stator pole carrier, for example. It also simplifies the overall assembly of the gearless conveyor drive.

[0050] The pipes may be connected to one or more cooling fins. The cooling fin(s) may be located at one or both axial ends of the stator pole carrier.

[0051] The stator assembly may comprise a support shaft. The support shaft may be used to support the stator assembly and the rotor assembly. In particular, the rotor assembly may be mounted to the support shaft by bearings. The support shaft may be a stationary shaft. In one arrangement, the support shaft may be stationary during normal operation of the gearless conveyor drive but may be rotated relative to stationary support structures at the axial ends of the support shaft if one of the stator pole modules that is obstructed by the support structure needs to be removed from the stator pole carrier in the axial direction. The support shaft and the stator pole carrier that is mounted thereon may be rotated until the particular stator pole module that needs to be removed is no longer in line with the support structures. In another arrangement, a particular stator pole module may be removed through an opening or void that is created in one of the support structures without any need to rotate the support shaft. Both of these arrangements are described in more detail below.

[0052] The support shaft may comprise a central shaft part and a mounting part that is displaced radially outwardly from the central shaft part and on which the substantially tubular stator pole carrier is mounted. The mounting part may be defined by a plurality of circumferentially-spaced ribs that extend radially outwardly from the central shaft part. The central shaft part may extend axially beyond the end plates and may be supported at both axial ends by a respective stationary support structure. The central shaft part may include a central bore that receives circuit inlet and outlet pipes of a liquid cooling circuit for the stator assembly, for example. The central bore may also receive electrical cables for providing an electrical connection between the stator winding and an external variable speed drive. The stator pole carrier is fixedly mounted to the ribs, e.g., welded or bonded to the radially outer face of the ribs. The stator pole carrier may also be an interference fit on the ribs of the support shaft or may be mounted using axially- extending support bars, for example. A plurality of axially-extending passages may be provided between the central shaft part and the radially inner surface of the stator pole carrier and are adapted to receive cooling air for cooling the stator assembly. Each passage may be defined between an adjacent pair of radial ribs.

[0053] As explained briefly above, cooling air may be circulated by one or more fan blades provided on the inner surface of at least one of the end plates. The fan blades are adapted to move cooling air through the one or more air cooling circuits for cooling the stator assembly when the rotor assembly is rotating. One or more fan blades may be provided on both of the end plates. If fan blades are provided on only one of the end plates, cooling air preferably flows from one axial end of the stator pole carrier to the other axial end - i.e., in one direction. In particular, the cooling air will flow from the axial end of the stator pole carrier that faces the fan blades to the other axial end of the stator pole carrier. The cooling air may flow through one or more of:

[0054] - the annular air gap between the stator assembly and the rotor assembly, where the cooling air flows past and between the stator pole modules,

[0055] - the passage in each of the stator pole modules, and the passages between the shaft ribs - i.e., between the central shaft part and the stator pole carrier.

[0056] If fan blades are provided on both of the end plates, cooling air preferably flows through the annular air gap between the stator assembly and the rotor assembly from one axial end of the stator pole carrier towards the middle of the stator pole carrier and from the other axial end of the stator pole carrier towards the middle of the stator pole carrier - i.e., in opposite directions. At an intermediate location between the axial ends of the stator pole carrier, typically at or near the middle of the stator pole carrier in the axial direction, the cooling air may flow radially inwardly through one or more radially- extending passages in the stator pole carrier and the mounting part of the support shaft, and may then flow axially through the passages in the support shaft - i.e., between the central shaft part and the mounting part back towards the end plates. Cooling air may also flow through the passages from one axial end of the rotor core to the other axial end if fan blades are provided on both of the end plates - e.g., if the fan blades on one of the end plates are arranged to “push” the cooling air towards the other end plate, and the fan blades on the other end plate are arranged to “pull” the cooling air towards it. The cooling air will therefore flow in one direction through the stator assembly.

[0057] In one arrangement, the stator pole carrier may be provided in two parts separated in the axial direction by a gap through which the cooling air may flow (i.e., the stator assembly may have a split stator pole carrier). Each part of the stator pole carrier may have its own liquid cooling circuit(s). For example, each part of the stator pole carrier may have a plurality of axially-extending passages where each passage extends between an inlet opening and an outlet opening. The inlet and outlet openings of each part of the stator pole carrier may be fluidly connected by a plurality of pipes such that the passages and the pipes define one or more liquid cooling circuits for each part of the stator pole carrier. The two parts of the stator pole carrier may also be cooled by the same liquid cooling circuit(s), i.e., where pipes may span the gap between the two parts of the stator pole carrier and fluidly connect inlet and / or outlet openings in one part of the stator pole carrier with inlet and / or outlet openings in the other part. The gap between the two parts of the stator pole carrier allows the cooling air to flow into the axially-extending passages between the central shaft part and the radially inner surface of the stator pole carrier. The two parts of the stator pole carrier may be assembled onto the support shaft from opposite axial ends and may be abutted against a step formed on the mounting part - e.g., a raised step provided on the radially outer face of each radially-extending rib. The axial dimension of the step will determine the axial width of the gap between the parts of the split stator pole carrier. It will be understood that other designs may be used to maintain the required gap or separation, including those that would allow both parts of the stator pole carrier to be assembled onto the support shaft from the same axial end.

[0058] Each stator pole module may be removably mounted to both parts of the stator pole carrier. Engagement profiles in the radially outer surface of each part of the stator pole carrier may be aligned with each other so that each stator pole module may be inserted into both parts of the stator pole carrier in the axial direction. Each stator pole module will therefore span the gap between the two parts of the stator pole carrier. If each stator pole module comprises an axially -extending passage that extends from one axial end of the stator pole module to the other axial end, each stator pole module may also comprise one or more radially-extending passages. Cooling air may therefore flow from both ends of each stator pole module towards the middle of each stator pole module before flowing radially inwardly through the radially-extending passage(s) in each stator pole module and then through the gap between the two parts of the stator pole carrier, or through one or more other radially-extending passages in the stator pole carrier and the mounting part of the support shaft, for example. The cooling air may flow back towards the end plates through the one or more axially-extending passages in the support shaft.

[0059] Cooling air may therefore be circulated around the stator assembly in a closed-loop air cooling circuit that comprises one or more of:

[0060] - the annular air gap between the stator assembly and the rotor assembly, where the cooling air flows past and between the stator pole modules,

[0061] - the passage in each of the stator pole modules, and the passages in the support shaft - i.e., between the central shaft part and the stator pole carrier.

[0062] The gearless conveyor drive may also comprise one or more of the other features described above and below - e.g., those features that relate to the improved cooling of the rotor assembly, the brake disc, and that allow for unobstructed removal of one or more of the stator pole modules.

[0063] The present invention further provides a method of cooling a gearless conveyor drive for driving a conveyor belt of a conveyor system, the gearless conveyor drive comprising: a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt; and a stator assembly radially inside the rotor assembly, the stator assembly comprising a substantially tubular stator pole carrier and a plurality of stator pole modules that are removably mounted to the stator pole carrier, wherein the stator pole carrier comprises a plurality of axially-extending passages, each passage extending between an inlet opening and an outlet opening, and wherein the inlet and outlet openings are fluidly connected by a plurality of pipes such that the passages and the pipes define one or more liquid cooling circuits; the method comprising passing cooling liquid (e.g., water) through the one or more liquid cooling circuits to cool the stator assembly.

[0064] The method may further comprise passing cooling air through one or more passages in the stator assembly and / or through the annular air gap between the stator assembly and the rotor assembly to cool the stator assembly. It may be assumed the cooling air flowing through the air gap also flows between the stator pole modules that are mounted to the radially outer surface of the stator pole carrier.

[0065] The one or more passages in the stator assembly may comprise the above-described axially-extending passage in the body of each stator pole module, and the axially- extending passages in the support shaft - i.e., between the central shaft part and the stator pole carrier. The one or more passages may also comprise a radially-extending passage in the body of each stator pole module, or one or more radially-extending passages in the stator pole carrier or the gap between the two parts of a split stator pole carrier described above, for example.

[0066] The cooling air may be circulated around the stator assembly in a closed-loop air cooling circuit.

[0067] The improved cooling of the stator assembly increases the power density of the gearless conveyor drive.

[0068] Brake disc

[0069] According to a third aspect of the present invention, the gearless conveyor drive comprises a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt, and a rotor core mechanically mounted to a radially inner surface of the barrel, wherein the barrel further comprises a radially -extending brake disc.

[0070] The brake disc is therefore formed as part of the barrel of the rotor assembly. The resulting gearless conveyor drive is physically compact and is different from other known drives that may have a separate brake disc, or where the brake disc is formed as part of an end plate of the rotor assembly. In the latter case, the braking function is therefore lost if the end plate needs to be removed for any reason.

[0071] The brake disc may increase the strength and stiffness of the barrel, particularly under braking conditions.

[0072] The brake disc may be used for emergency braking of the gearless conveyor drive and / or to keep the rotor assembly stationary during maintenance or repair, for example.

[0073] The brake disc may form part of an external braking assembly having any suitable construction. The braking assembly may also comprise one or more brake pads that may be brought into friction contact with the annular surface(s) of the brake disc when braking of the rotor assembly is required. The one or more brake pads may be mounted on a brake calliper, for example.

[0074] A suitable friction coating may be applied to one or both of the annular surfaces of the brake disc.

[0075] The brake disc preferably extends radially outwardly from the barrel.

[0076] The brake disc may be formed as an integral part of the barrel, for example as part of a rigid structural tube of the barrel that may be made of a suitable metal or metal alloy (e.g., steel or aluminium) and that functions as the main structural part of the barrel - see above. The brake disc may be one of forged, welded and shrink-fitted to the barrel, e.g., to the rigid structural tube. Such a brake disc will not normally be easily replaced and so it may have an increased thickness to allow for surface regrinds of its annular surface(s) to prolong its use.

[0077] The brake disc may also be formed as a separate component that is fixedly connected to the barrel, e.g., to the rigid structural tube, by one or more mechanical fixings such as bolts that allow the brake disc to be removed. Removing the one or more mechanical fixings using a suitable tool allows the brake disc to be removed and replaced if necessary. Removing the brake disc may make it easier to apply a new friction coating or easier to carry out a regrinding process, for example. The rigid structural tube may comprise an integral radially-extending flange and the brake disc may be removably mounted to the tube flange by the one or more mechanical fixings. The brake disc may be formed in a plurality of segments, each segment being separately connected to the tube flange with one or more mechanical fixings. The brake disc may be segmented with each brake disc segment being fixedly connected to the barrel, e.g., to the rigid structural tube, and / or the adjacent brake disc segments by one or more mechanical fixings such as bolts that allow each segment to be removed if required. It will be understood that a segmented brake disc will normally require a connection in the circumferential direction because this is the direction of braking torque. The segmented construction may facilitate removal of the brake disc. For example, it may allow the brake disc to be removed without the need to first remove the conveyor belt from the barrel. A segmented brake disc may also be removed as individual segments if there is a radially-extending flange at the other axial end of the barrel, which flange might otherwise obstruct or prevent the removable of a non-segmented brake disc in that axial direction. In some cases, it may also be necessary to remove only one or two of the individual brake disc segments in order to carry out the necessary repairs or replacement.

[0078] The brake disc may be constructed as a “floating” brake disc. For example, the brake disc may be formed as a separate component that fixedly connected to the barrel, e.g., to the rigid structural tube, by one or more mechanical fixings that allow for some limited relative movement between the brake disc and the barrel. (This may be directly contrasted with conventional mechanical fixings such as bolts where there is no relative movement at all between the brake disc and the barrel.) The mechanical fixings for connecting the “floating” brake disc may be bobbins or rivets or rectangular keys, for example. The mechanical fixings may be received through aligned openings in the brake disc and a radially -extending flange of the barrel. The mechanical fixings for connecting the “floating” brake disc to the barrel may be formed in two or more pieces because this normally allows for easier assembly and removal of the mechanical fixings and the brake disc. If the mechanical fixings are formed in two or more pieces (e.g., as a multi-piece bobbin or the like) the separate pieces may be fixedly connected together using one or more threaded fasteners or rivets, or by means of a push fit, screw fit or interference connection, for example. The mechanical fixings may comprise radial springs to provide dynamic concentricity control if required. More particularly, the radial springs may be used to adjust the relative movement that is permitted by the mechanical fixings. Using a “floating” brake disc may reduce heat dissipation into the barrel and may prevent warping of the brake disc as a result of heat generated during braking. It would also allow the brake disc to be removed. The “floating” brake disc may be formed in a plurality of segments, each segment being separately connected to the barrel with one or more mechanical fixings. This may also allow for some limited relative movement between the individual segments of the “floating” brake disc. Cut- out portions or voids may be provided to reduce the contact area between the “floating” brake disc and the barrel. Such cut-out portions may be circumferentially spaced around the barrel and may be positioned between the mechanical fixings, for example.

[0079] The brake disc may be used to removably mount an adjacent end plate. The brake disc may comprise a plurality of circumferentially-spaced fixing openings. Mechanical fixings such as bolts are received in a plurality of aligned circumferentially-spaced fixing openings in the radially outer part of the end plate and then into the fixing openings in the brake disc. The brake disc may therefore function as a radially- extending flange for removably mounting an end plate to an axial end of the structural tube.

[0080] The brake disc may comprise one or more locking holes adapted to receive a locking pin of an external locking mechanism. The locking pin may be moved in the axial direction between a locking position where it is engaged in an aligned locking hole and a non-locking position where it is not engaged and the rotor assembly is free to rotate. When the locking pin is engaged in a locking hole, the rotor assembly is prevented from rotating by the locking mechanism. This may be necessary when the gearless conveyor drive is undergoing maintenance or repair, for example. The brake disc may comprise a plurality of locking holes that may be circumferentially spaced around the brake disc. This may allow the rotor assembly to be locked in a particular annular position, e.g., so that an access opening of one of the end plates is aligned with a particular stator pole module. This is described in more detail below. It would allow the stator pole module to be removed in the axial direction through the aligned access opening without having the remove the whole of the end plate.

[0081] The brake disc may be a vented brake disc and may comprise one or more vent holes or vent openings. The brake disc may comprise a plurality of vent holes or vent openings that may be circumferentially spaced around the brake disc. Vent holes or vent openings may be arranged in any suitable pattern and may be interspersed with the optional locking holes. The brake disc may be at an axial end of the barrel.

[0082] A second brake disc may be provided at the other axial end of the barrel. The second brake disc may be formed and fitted to the rigid structural tube in the same way as the first brake disc described above. A second brake disc may be provided if additional braking capability is needed, or if balanced braking is preferred. If a brake disc is provided at both axial ends of the barrel, the brake discs may provide additional protection for the conveyor belt which will be located axially between them.

[0083] The gearless conveyor drive may also comprise one or more of the other features described above and below - e.g., those features that relate to the improved cooling of the rotor assembly and the stator assembly, and that allow for unobstructed removal of one or more of the stator pole modules.

[0084] Support structure with one or more openings

[0085] According to a fourth aspect of the present invention, the gearless conveyor drive comprises: a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt; a stator assembly radially inside the rotor assembly, the stator assembly comprising: a substantially tubular stator pole carrier and a plurality of stator pole modules that are removably mounted to the stator pole carrier, and a stationary shaft on which the stator pole carrier is mounted; and a pair of support structures, each support structure supporting a respective axial end of the stationary shaft; wherein at least one of the support structures comprises a lower section, an upper section that supports the axial end of the stationary shaft, and an intermediate section between the lower section and the upper section and that is axially aligned with one or more of the stator pole modules (so-called “aligned stator pole module(s)”); and wherein the intermediate section of the at least one of the support structures comprises at least one removable member adapted to be selectively removable from the remainder of the support structure to thereby create an opening in the support structure that is sized and shaped to allow at least a selected one of the aligned stator pole modules to be removed from the stator pole carrier in the axial direction through the opening.

[0086] It will be understood that some of the stator pole modules will be axially aligned with the support structures. This will normally prevent these stator pole modules from being easily removed from the stator pole carrier if they develop a fault, for example. In particular, even if the end plate includes an access opening that may be aligned with the stator pole modules by rotating the rotor assembly, these aligned stator pole modules could only be moved so far in the axial direction before coming into direct contact with the support structure at the respective axial end of the gearless conveyor drive. This problem may be overcome by selectively creating an aligned opening or void in at least one of the support structures through which a faulty stator pole module may be removed using suitable tooling. The opening or void in the support structure may be created as part of a stator pole module removal and / or insertion operation.

[0087] The at least one of the support structures is preferably constructed so that all of the aligned stator pole modules that would otherwise be obstructed by the support structure may be removed from the stator pole carrier in the axial direction. The intermediate section may therefore comprise two or more removable members. Removing each removable member may create a respective opening or void in the support structure. The opening created when a particular removable member is removed may be sized and shaped to allow two or more of the aligned stator pole modules to be removed from the stator pole carrier in the axial direction. One or more of a plurality of aligned stator pole modules may therefore be selectively removed from the stator pole carrier through the same opening. All of the aligned stator pole modules may therefore be removed by creating a relatively small number of openings or voids in the support structure. This may simplify the construction of the support structure by minimising the number of removable members that are needed. If the intermediate section of the at least one of the support structures comprises two or more removable members, the opening or void created by removing one of the removable members may allow one or more of the stator pole members that are aligned with that particular opening to be removed, and the opening created by removing another one of the removable members may allow one or more of the stator pole members that are axially aligned with that particular opening to be removed. Removing each removable member from the support structure therefore allows different aligned stator pole modules to be removed through the opening or void that is created. A gap may be provided between removable members or between a removable member and the remainder of the support structure, for example to accommodate assembly tolerances. Each gap may be filled with one or more removable shim packs.

[0088] If a selected one of the aligned stator pole module needs to be removed from the stator pole carrier, e.g., because it is faulty and needs to be repaired, a particular removable member may be removed from the remainder of the support structure to create an opening or void that is aligned with the faulty stator pole module and through which the faulty stator pole module may be removed. A replacement stator pole module may also be inserted into the stator pole carrier through the same opening. If two or more of the aligned stators poles need to be removed, the removable members may be removed and re-inserted into the support structure as required.

[0089] Each removable member may be removably mounted or connected to the remainder of the support structure, e.g., to one or both of the lower and upper sections, and optionally to another removable member, by one or more mechanical fixings such as bolts. Normally only one removable member will be removed from the support structure at any time. Removing only one of the removable members typically means that the structural integrity of the remaining support structure is maintained - i.e., the rotor assembly and stator assembly will remain properly supported at all times. It will normally only be necessary to remove one of the removable members to create an opening or void through which a faulty stator pole module may be removed. However, in some circumstances, it may be necessary to remove two removable members to create a larger opening to provide additional access, or if the faulty stator pole module that needs to be removed is aligned with two adjacent removable members of the support structure so that it cannot be removed by removing only one of the removable members, for example.

[0090] The lower section of the at least one of the support structures may define a footplate for mounting the support structure, e.g., on a suitable foundation.

[0091] The upper section of the at least one of the support structures may comprise an opening having a non-circular cross-section for receiving the axial end of the stationary support shaft having a corresponding non-circular cross-section. This prevents any relative rotation between the support shaft and the support structure. Both support structures may comprise such an opening having a non-circular cross-section and both axial ends of the support shaft may have a corresponding non-circular cross-section.

[0092] The barrel may comprise a rigid structural tube that may be made of a suitable metal or metal alloy (e.g., steel or aluminium) and functions as the main structural part of the barrel. The radially inner surface of the tube may be substantially cylindrical and may define the radially inner surface of the barrel. The radially outer surface of the tube may be substantially cylindrical.

[0093] The rotor assembly may further comprise a pair of end plates. The end plates may be made of a suitable metal or metal alloy (e.g., steel or aluminium). Each end plate may be located at an axial end of the barrel and is adapted to rotatably mount the rotor assembly. Each end plate may be mounted to the barrel, e.g., to the rigid structural tube. In particular, the radially outer part of each end plate may be removably mounted to the respective axial end of the rigid structural tube using one or more mechanical fixings such as bolts so that each end plate may be removed if necessary. A radially- extending flange may be provided at both axial ends of the rigid structural tube. Each flange may comprise a plurality of circumferentially-spaced fixing openings. A plurality of circumferentially-spaced fixing openings may be provided in the radially outer part of each end plate - the respective fixing openings in each end plate and each tube flange being aligned to receive the mechanical fixings to removably mount each end plate to the rigid structural tube. A rotor core of the rotor assembly may be positioned in the space defined by the barrel and the end plates. The radially inner part of each end plate may also be mounted to a stationary part of the gearless conveyor drive (e.g., the stationary support shaft of the stator assembly) by a respective bearing assembly. The rotor assembly comprising the barrel, the rotor core and the end plates may therefore rotate relative to the stationary part of the gearless conveyor drive when electrical power is supplied to the stator assembly to operate the gearless conveyor drive.

[0094] At least one of the end plates may comprise one or more access openings. Each access opening is aligned with the stator pole modules - i.e., positioned at the same radial distance from the rotation axis of the rotor assembly as the stator pole modules. If two or more access openings are provided, they are circumferentially spaced around the end plates. Each access opening may be covered by a removable access cover. To remove the selected one of the aligned stator pole modules, the rotor assembly may be rotated until an access opening in the end plate is aligned with the stator pole module to be removed. Providing two or more access openings in the end plate may reduce the angle through which the rotor assembly needs to be rotated in order to align one of the access openings with the stator pole module to be removed. The removable member of the support structure is removed to create the opening or void in the support structure, and the stator pole module is removed in the axial direction through the aligned openings in the end plate and the support structure. An access opening in the end plate may be sized and shaped to correspond generally to the size and shape of an opening or void created in the support structure when a removable member is removed. The rotor assembly may be rotated before or after the removable member is removed from the support structure to create the opening or void in the support structure.

[0095] It will be understood that the one or more access openings in the end plates may also be used to remove a stator pole module that is not obstructed by the support structure - for example, a stator pole module that is located on a side part or on the upper part of the stator pole carrier. In this case, the rotor assembly may be rotated until an access opening in the end plate is aligned with the stator pole module to be removed. The stator pole module is removed in the axial direction through the access opening in the end plate.

[0096] It may normally only be necessary to remove stator pole modules from one axial end of the gearless conveyor drive. In this case, only one of the support structures needs to comprise one or more removable members and only one of the end plates needs to include the one or more access openings. However, both of the support structures and the end plates may be constructed as described above if it is necessary to remove stator pole modules from both axial ends of the gearless conveyor drive.

[0097] The gearless conveyor drive may also comprise one or more of the other features described above - e.g., those features that relate to the improved cooling of the rotor assembly and the stator assembly, and the brake disc. If the gearless conveyor drive comprises a brake disc with one or more locking openings, the locking mechanism may be used to prevent the rotor assembly from rotating while a faulty stator pole module is being removed from the stator pole carrier through the end plate, or while a replacement stator pole module is being inserted into the stator pole carrier through the end plate. For example, the locking pin of the locking mechanism may be inserted into one of the locking openings after the rotor assembly has been rotated to align an access opening in the end plate with the stator pole module to be removed. The locking openings may be located in the brake disc so that the rotor assembly may be selectively locked in a suitable position during the stator pole module removal and / or insertion operation.

[0098] Rotatable stator assembly

[0099] According to a fifth aspect of the present invention, the gearless conveyor drive comprises: a rotor assembly comprising a substantially tubular barrel having a radially outer surface adapted to contact the conveyor belt; a stator assembly radially inside the rotor assembly, the stator assembly comprising: a substantially tubular stator pole carrier and a plurality of stator pole modules that are removably mounted to the stator pole carrier, and a shaft on which the stator pole carrier is mounted; and a pair of support structures, each support structure supporting a respective axial end of the shaft; wherein the gearless conveyor drive is selectively reconfigurable between a first configuration, e.g., during normal operation of the gearless conveyor drive, where the shaft may not rotate relative to the support structures (i.e., where the shaft is held stationary), and a second configuration, e.g., during a stator pole module removal and / or insertion operation, where the shaft and the mounted stator pole carrier may rotate relative to the support structures.

[0100] It will be understood that some of the stator pole modules (e.g., those modules that extend around the lower part or the sides parts of the stator pole carrier) will be axially aligned with the support structures (so-called “aligned stator pole modules”). This will normally prevent these stator pole modules from being easily removed from the stator pole carrier if they develop a fault, for example. In particular, even if the end plate includes an access opening that may be aligned with the stator pole modules by rotating the rotor assembly, these aligned stator pole modules could only be moved so far in the axial direction before coming into direct contact with the support structure at the respective axial end of the gearless conveyor drive. Which stator pole modules are aligned and which are not aligned will depend on the construction or design of the support structures. This problem may be overcome by selectively allowing the support shaft and the stator pole carrier to rotate relative to the support structures so that a faulty stator pole module is no longer aligned with the support structures in the axial direction.

[0101] When the gearless conveyor drive is in the first configuration, the support shaft may be fixedly connected to the support structures without being able to rotate by one or more of the following:

[0102] - one or more mechanical fixings such as bolts,

[0103] - one or more keys received in respective aligned keyways, and

[0104] - any suitable locking mechanism that holds the support shaft stationary during normal operation of the gearless conveyor drive, for example. Removing the mechanical fixings and / or the one or more keys, and / or unlocking or releasing the locking mechanism, may allow the support shaft to rotate relative to the support structures during a stator pole module removal and / or insertion operation. When the support shaft may rotate, the gearless conveyor drive is in the second configuration.

[0105] At least one of the support structures and the supported axial end of the support shaft may both comprise a keyway into which a removable key may be inserted when the respective keyways are radially aligned. One key way may be defined by an axially- extending recess formed in a surface of the support structure and the other key way may be defined by an axially-extending recess formed in the surface of an axial end of the support shaft that faces the support structure surface. When the key is received in the aligned keyways, rotation of the support shaft relative to the support structures is prevented. Otherwise, when the key is not received in the aligned keyways, rotation of the support shaft relative to the support structures is permitted. The key may be formed as a bar and may have any suitable cross-section, e.g., a square or rectangular crosssection. It will be understood that the cross-section of the key will correspond to the cross-section of the aligned key ways. Two or more keys may be used. In this case, the surface of the support structure may include two or more axially-extending recesses and the axial end of the support shaft may include two or more axially-extending recesses.

[0106] At least one of the support structures may comprise a lower section and an upper section that are removably mounted to each other. The lower section of the at least one of the support structures may define a footplate for mounting the support structure, e.g., on a suitable foundation.

[0107] The lower and upper sections of the at least one of the support structures may each define part of a D-shaped opening for receiving an axial end of the support shaft. In particular, the lower section may define a lower part of the D-shaped opening and the upper section may define an upper part of the D-shaped opening. The axial end of the support shaft that is supported by the at least one of the support structures may have a corresponding D-shaped cross-section with an arcuate lower surface that is in contact with, and is supported by, a corresponding supporting arcuate surface of the lower section that allows for relative rotation between the support shaft and the support structure if the upper section is removed, and a flat upper surface that is in contact with a corresponding flat surface of the upper section when it is fixedly connected to the lower section. When the lower section and the upper section are fixedly connected together - e.g., by one or more mechanical fixings such as bolts - rotation of the support shaft relative to the support structures is mechanically prevented by the contacting flat surfaces of the support shaft and the upper section. However, if the upper section is removed from the lower section - e.g., by removing the one or more mechanical fixings and then removing the upper section - the support shaft may rotate relative to the support structures. The upper section therefore functions as a locking mechanism. When the upper section is fixedly connected to the lower section, the gearless conveyor drive is in the first configuration, and when the upper section is removed, the gearless conveyor drive is in the second configuration.

[0108] When the upper section is removed, the support shaft and the stator pole carrier may be rotated through a sufficient angle so that the faulty stator pole module is no longer obstructed by the support structure and may be removed from the stator pole carrier in the axial direction. A replacement stator pole module may also be inserted into the stator pole carrier. Rotation of the support shaft is preferably prevented while a stator pole module is being removed or installed. In other words, after the support shaft has been rotated to allow a particular stator pole module to be removed or a new stator pole module to be inserted into the stator pole carrier, the support shaft is preferably temporary held in this rotated position until the removal and / or insertion operation is completed. The support shaft and the stator pole carrier may then be rotated back to their normal position and the upper section may be fixedly reconnected to the lower section. One or more keys may also be removed from aligned key ways in the support structure and the support shaft before the support shaft is rotated and may be inserted back into the aligned key ways afterwards. The key ways and the key(s) may maintain shaft alignment before the upper section is reconnected to the lower section. In other words, when the support shaft has been rotated back to its normal position, the one or more keys may be inserted back into their respective aligned keyways to prevent any further rotation of the support shaft before the upper section of the support structure is fixedly reconnected to the lower section, e.g., using the one or more mechanical fixings. The key ways may be used as a guide when rotating the support shaft back to its normal position - i.e., rotation may be stopped when the respective keyways are aligned. Aligned keyways may also be used when rotating the support shaft so that the faulty stator pole module is no longer obstructed by the support structure and one or more keys may be inserted when respective keyways are aligned to prevent further rotation of the support shaft while the faulty stator pole module is removed and a replacement stator pole module is inserted, for example.

[0109] When the gearless conveyor drive is in the second configuration, the support shaft may be rotated by a suitable tool that may be attached to an axial end of the support shaft. It will be understood that rotating the support shaft also rotates the stator pole carrier that is fixedly mounted to the support shaft. The support shaft may typically be allowed to rotate in both directions - i.e., clockwise and anti-clockwise directions. The direction in which the support shaft is rotated will normally depend on the location of the stator pole module to be removed. The tool may be used to rotate the support shaft and hold the support shaft stationary (i.e., prevent further rotation) while the faulty stator pole module is removed and a replacement stator pole module is inserted into the stator pole carrier.

[0110] Both support structures and both axial ends of the support shaft may have the same construction. This means that rotation of the support shaft is only possible if the upper section of both of the support structures is removed. Alternatively, the other axial end of the support shaft may have a circular cross-section and the other support structure may have a corresponding circular opening for supporting the other axial end of the support shaft. In other words, the other axial end of the support shaft may always be rotatable relative to its respective support structure so that rotation is only prevented at one axial end of the stator assembly. Alternatively, one or more keys and key ways may be used at both axial ends of the support shaft even if only one axial end of the support shaft has the D-shaped cross-section mentioned above and is received in a support structure having upper and lower sections, for example. The barrel may comprise a rigid structural tube that may be made of a suitable metal or metal alloy (e.g., steel or aluminium) and functions as the main structural part of the barrel. The radially inner surface of the tube may be substantially cylindrical and may define the radially inner surface of the barrel. The radially outer surface of the tube may be substantially cylindrical.

[0111] The rotor assembly may further comprise a pair of end plates. The end plates may be made of a suitable metal or metal alloy (e.g., steel or aluminium). Each end plate may be located at an axial end of the barrel and is adapted to rotatably mount the rotor assembly. Each end plate may be mounted to the barrel, e.g., to the rigid structural tube. In particular, the radially outer part of each end plate may be removably mounted to the respective axial end of the rigid structural tube using one or more mechanical fixings such as bolts so that each end plate may be removed if necessary. A radially- extending flange may be provided at both axial ends of the rigid structural tube. Each flange may comprise a plurality of circumferentially-spaced fixing openings. A plurality of circumferentially-spaced fixing openings may be provided in the radially outer part of each end plate - the respective fixing openings in each end plate and each tube flange being aligned to receive the mechanical fixings to removably mount each end plate to the rigid structural tube. A rotor core of the rotor assembly may be positioned in the space defined by the barrel and the end plates. The radially inner part of each end plate may also be mounted to the support shaft by a respective bearing assembly. The rotor assembly comprising the barrel, the rotor core and the end plates may therefore rotate relative to the stationary part of the gearless conveyor drive when electrical power is supplied to the stator assembly to operate the gearless conveyor drive.

[0112] At least one of the end plates may comprise one or more access openings. Each access opening is aligned with the stator pole modules - i.e., positioned at the same radial distance from the rotation axis of the rotor assembly as the stator pole modules. If two or more access openings are provided, they are circumferentially spaced around the end plates. Each access opening may be covered by a removable cover. To remove the selected one of the aligned stator pole modules - i.e., a stator pole module whose removal would otherwise be obstructed by the support structure - the stator assembly may be rotated until the stator pole module to be removed is no longer obstructed by the support structure. The rotor assembly may be rotated until an access opening in the end plate is aligned with the stator pole module to be removed. Providing two or more access openings in the end plate may reduce the angle through which the rotor assembly needs to be rotated in order to align one of the access openings with the stator pole module to be removed. The stator pole module is removed in the axial direction through the access opening in the end plate.

[0113] It will be understood that the one or more access openings in the end plates may also be used to remove a stator pole module that is not obstructed by the support structure - for example, a stator pole module that extends around the side or upper part of the stator pole carrier. In this case, there is no need to rotate the stator assembly. The rotor assembly may be rotated until an access opening in the end plate is aligned with the stator pole module to be removed. The stator pole module is removed in the axial direction through the access opening in the end plate.

[0114] It may normally only be necessary to remove stator pole modules from one axial end of the gearless conveyor drive. In this case, only one of the end plates needs to comprise one or more access openings. However, both of the end plates may be constructed as described above if it is necessary to remove stator pole modules from both axial ends of the gearless conveyor drive.

[0115] The gearless conveyor drive may also comprise one or more of the other features described above - e.g., those features that relate to the improved cooling of the rotor assembly and the stator assembly, and the brake disc. If the gearless conveyor drive comprises a brake disc with one or more locking openings, the locking mechanism may be used to prevent the rotor assembly from rotating while a faulty stator pole module is being removed from the stator pole carrier through the end plate, or while a replacement stator pole module is being inserted into the stator pole carrier through the end plate. For example, the locking pin of the locking mechanism may be inserted into one of the locking openings after the rotor assembly has been rotated to align an access opening in the end plate with the stator pole module to be removed. The locking openings may be located in the brake disc so that the rotor assembly may be selectively locked in a suitable position during the stator pole module removal and / or insertion operation.

[0116] Drawings

[0117] Figure 1 is a perspective view of a first axial end of a gearless conveyor drive according to the present invention;

[0118] Figure 2 is a perspective view of a second axial end of the gearless conveyor drive of Figure 1;

[0119] Figure 3 is a perspective view of the barrel of the gearless conveyor drive of Figure 1;

[0120] Figure 4 is an end view of the barrel of the gearless conveyor drive of Figure 1;

[0121] Figure 5 is a perspective view of the segmented rotor core of the gearless conveyor drive of Figure 1;

[0122] Figure 6 is a perspective view of a rotor core segment;

[0123] Figure 7 is an end view of the rotor core segment of Figure 6;

[0124] Figure 8 is a perspective view of the stator pole carrier of the gearless conveyor drive of Figure 1;

[0125] Figure 9 is an end view of the rotor core segment of Figure 8;

[0126] Figure 10 is a perspective view of a stator coil module of the gearless conveyor drive of Figure 1;

[0127] Figure 11 is an end view of the stator pole module of Figure 10;

[0128] Figure 12 is a perspective view of the stator pole carrier of Figure 8 with liquid cooling circuits;

[0129] Figure 13 is a detail view of the stator pole carrier of Figure 12;

[0130] Figure 14 is a detail view of the U-shaped pipes of a liquid cooling circuit with optional fins;

[0131] Figure 15 is a perspective view of a support shaft of the gearless conveyor drive of Figure 1;

[0132] Figure 16 is a side view of the support shaft of Figure 15;

[0133] Figure 17 is an end view of the support shaft of Figure 15; Figure 18 is a side view of a split stator pole carrier mounted on the support shaft of Figure 15;

[0134] Figure 19 is a perspective view of the split stator pole carrier of Figure 18 without the support shaft;

[0135] Figures 20a and 20b are a perspective view of part of the gearless conveyor drive of Figure 1 showing the stator pole carrier and support shaft of Figures 12 and 15 mounted inside the barrel of Figure 3;

[0136] Figures 21a and 21b are an end view of a first axial end of the part of the gearless conveyor drive of Figures 20a and 20b;

[0137] Figures 22a and 22b are an end view of a second axial end of the part of the gearless conveyor drive of Figures 20a and 20b;

[0138] Figures 23a and 23b are a cross-section view of the gearless conveyor drive of Figure i;

[0139] Figure 24 is a cross-section view taken along line A-A of Figure 23a showing an end plate;

[0140] Figures 25a and 25b are a cross-section view taken along line B-B of Figure 23b;

[0141] Figures 26A and 26B are detail views of the barrel of Figure 3 with a removable brake disc;

[0142] Figures 27A and 27B are detail views of an alternative barrel with a removable brake disc;

[0143] Figure 28 is an end view of an alternative barrel where the brake disc has vent openings; Figure 29 is a perspective view of a first axial end of an alternative barrel with an integral brake disc;

[0144] Figure 30 is a perspective view of a second axial end of the alternative barrel of Figure 29;

[0145] Figure 31 is a detail view of the barrel of Figure 29;

[0146] Figure 32A is a schematic view of an alternative barrel with a “floating” brake disc;

[0147] Figures 32B to 32F are detail views of different bobbins that may be used in the “floating” brake disc of Figure 32A;

[0148] Figures 33 to 35 are schematic views of alternative barrels with a “floating” brake disc; Figure 36 is a perspective view of an alternative gearless conveyor drive with support structures having removable members; Figure 37 is an end view of the gearless conveyor drive of Figure 36;

[0149] Figures 38 to 40 are end views of the gearless conveyor drive of Figure 36 with different removable members removed to create an opening or void in the support structure;

[0150] Figure 41 is a perspective view of an alternative gearless conveyor drive with rotatable support shaft;

[0151] Figure 42 is a perspective view of the gearless conveyor drive of Figure 41 with the upper part of each support structure removed to allow rotation of the support shaft;

[0152] Figure 43 is a perspective view of the gearless conveyor drive of Figure 41 with the tool for rotating the support shaft; and

[0153] Figure 44 is a perspective view of the gearless conveyor drive of Figure 41 with the tool fitted to the support shaft and the shaft rotated.

[0154] Specific description

[0155] Referring to Figures 1 to 31, a gearless conveyor drive 1 is configured as a large- diameter, low-speed synchronous electric motor and includes a rotor assembly 2, a stator assembly 50, and end support structures 200, 202 for supporting the rotor and stator assemblies.

[0156] The rotor assembly 2 includes a substantially tubular barrel 4 having a radially outer surface 4a that is adapted to contact a conveyor belt CB - see Figures 26A, 26B, 27A, 27B and 31, for example. The barrel 4 includes a rigid structural tube 6 that may be made of a suitable metal or metal alloy (e.g., steel, stainless steel or aluminium) and functions as the main structural part of the barrel. The barrel 4 is more clearly shown in Figures 3 and 4. The tube 6 has a substantially radially outer surface 6a that directly contacts the conveyor belt CB and defines the radially outer surface 4a of the barrel 4. The tube 6 has a substantially radially inner surface 6b that defines the radially inner surface 4b of the barrel 4. Although not shown, a protective outer layer may be adhered to the radially outer surface 6a of the tube 6 by a suitable adhesive. The outer layer (not shown) may be made of a suitable material (e.g., such as rubber) and is designed to protect the tube 6 from wear and tear. The outer surface of the outer layer (not shown) may be formed with a textured surface such as a diamond or square texture, for example, which may help to increase friction between the conveyor belt and the barrel 4 and reduce slippage.

[0157] The rotor assembly 2 also includes a segmented rotor core 8 - see Figures 5 to 7. A plurality of rotor core segments 10 are mechanically mounted to the radially inner surface 6b of the tube 6 by a plurality of circumferentially-spaced and axially-extending mounting members 12. The mounting members 12 are most clearly shown in Figures 3 and 4 and are located radially between the barrel 4 and the rotor core 8. Each mounting member 12 (or support bar) is formed as a separate component and is fixedly connected to the radially inner surface 6b of the tube 6 by a plurality of bolts. The mounting members 12 are made of a non-magnetic material (e.g., stainless steel). The mounting members may also be integrally formed as part of the tube 6.

[0158] Each mounting member 12 has a dovetail shaped cross-section that defines an engagement profile. An engagement profile may also be defined by a radially- extending protrusion or part of each mounting member.

[0159] Each rotor core segment 10 (see Figures 6 and 7) has an arcuate first surface 10a and an arcuate second surface 10b. The rotor core segments 10 are arranged circumferentially around the radially inner surface 4b of the barrel 4 so that their respective first arcuate surfaces 10a define a substantially cylindrical radially inner surface 8a of the rotor core 8 that faces radially inwardly towards the stator assembly 50 of the gearless conveyor drive 1. The respective second arcuate surfaces 10b of the rotor core segments 10 define a substantially cylindrical radially outer surface 8b of the rotor core 8 that faces radially outwardly towards the barrel 4.

[0160] The rotor core segments 10 have a laminated construction - i.e., they are formed from a stack of thin lamination sheets that are stamped or cut to have an outer profile. The lamination sheets may optionally be made of electrical grade steel with an insulating coating. The lamination sheets may be stacked together in the axial direction. The rotor core segments 10 may also have a bonded or solid construction. The second arcuate surface 10b of each rotor core segment 10 includes two dovetail shaped recesses 14, each recess 14 being designed to accommodate a corresponding dovetail shaped mounting member 12. Each recess and its corresponding mounting member therefore have complementary engagement profiles. It will be understood that other engagement profiles may be used, e.g., T-shaped profiles. Each recess 14 extends axially along the full length of the rotor core segment 10 as shown. Each rotor core segment 10 may include any suitable number of recesses 14 and may be mounted using any suitable number of mounting members 12. The recesses 14 may be at any suitable position in the second arcuate surface 10b. The rotor core may also be an interference fit on the mounting members. In this case, the rotor core is typically not segmented and is inserted into the barrel axially during an assembly process so that its radially outer surface is contacted and supported by the mounting members.

[0161] A plurality of circumferentially-spaced permanent magnet modules 16 are provided on the radially inner surface of the rotor core 8a - i.e., on the first arcuate surface 10a of each rotor core segment 10. Each permanent magnet module 16 may include one or more blocks of permanent magnet material. Each permanent magnet module 16 may be permanently or removably mounted to the radially inner surface 8a of the rotor core 8 by any suitable mounting means. The permanent magnet modules 16 are arranged circumferentially around the radially inner surface 8a of the rotor core 8 to define a plurality of rotor poles of alternating polarity. The permanent magnet modules 16 are spaced apart from a radially outer surface of the stator assembly 50 by an annular air gap 62.

[0162] Each rotor core segment 10 may move axially relative to the barrel 4 during an assembly process with each mounting member 12 received in its corresponding recess 14. Movement of each rotor core segment 10 in the radial and circumferential directions is restricted by the complementary engagement profiles of each recess 14 and the corresponding mounting member 12. During the assembly process, the mounting members 12 are fixedly connected to the tube 6 by the bolts and the rotor core segments 10 are then inserted into the tube 6 to form the complete rotor core 8.

[0163] Axially-extending passages 18 are provided between the radially inner surface 6b of the tube 6 and the radially outer surface 8b of the rotor core 8 - see Figures 21a, 21b, 22a, 22b and 24, for example. The passages 18 are adapted to receive cooling air for cooling the rotor assembly 2. Each passage 18 is defined between an adjacent pair of mounting members 12.

[0164] The passages 18 extend from one axial end of the rotor core 8 to the other axial end - i.e., along the axial direction of the rotor assembly 2.

[0165] The passages 18 provide improved cooling for the rotor assembly 2, meaning that less heat is transferred from the rotor core 8 to the barrel 4 when the gearless conveyor drive 1 is operating. If the barrel 4 of the rotor assembly 2 includes the optional protective outer layer (not shown) this may help to reduce the transfer of heat to the outer layer, thereby extending the lifetime of both the outer layer and the adhesive. The improved cooling increases the power density of the gearless conveyor drive 1.

[0166] Providing passages 18 between the rotor core 8 and the barrel 4 also minimises the transfer of magnetic flux to the barrel 4. This may be particularly beneficial if the conveyor belt CB is used to transport ferrous ores, for example, by reducing the number of ore particles that are magnetically attracted to the barrel 4.

[0167] Figures 21a, 21b, 22a, 22b, 25a and 25b, for example, show how the passages 18 define an almost continuous annular void between the barrel 4 and the rotor core 8 that is interrupted only by the mounting members 12.

[0168] The rotor assembly 2 further includes first and second end plates 20, 22. The end plates 20, 22 are made of a suitable metal or metal alloy (e.g., steel or aluminium). The first end plate 20 is located at a first axial end of the tube 6 and the second end plate 22 is located at a second axial end of the tube 6. A radially outer part of each end plate 20, 22 is removably mounted to the respective axial end of the rigid structural tube 6 using bolts so that the end plates 20, 22 may be removed if necessary. (If one or both of the end plates are removed, it will be understood that the barrel 4 and rotor core 8 may need to be properly supported.) A first radially-extending flange 24 is provided at the first axial end of the tube 6 and a second radially-extending flange 26 is provided at the second axial end of the tube 6. The first and second flanges 24, 26 include a plurality of circumferentially-spaced fixing openings 28. A plurality of circumferentially-spaced fixing openings 30 is provided in the radially outer part of each end plate 20, 22. The respective fixing openings 28, 30 in each tube flange 24, 26 and each end plate 20, 22 are aligned to receive bolts to removably mount each end plate 20, 22 to the rigid structural tube 6.

[0169] The radially inner part of each end plate 20, 22 is mounted to a support shaft 88 of the stator assembly 50 by a respective bearing assembly 90, 92. The first end plate 20 is mounted to a first axial end 88a of the support shaft 88 by a first bearing assembly 90 and the second end plate 22 is mounted to a second axial end 88b of the support shaft 88 by a second bearing assembly 92. The rotor assembly 2 is therefore rotatably mounted relative to the support shaft 88 by the end plates 20, 22. The rotor assembly 2 including the barrel 4, the rotor core 8 and the end plates 20, 22 may therefore rotate relative to the stationary part of the gearless conveyor drive 1 when electrical power is supplied to the stator assembly 50 to operate the gearless conveyor drive.

[0170] A plurality of fan blades 32 are formed on the inner surface of each end plate 20, 22 - see Figure 24 which shows fan blades on the end plate 20. The fan blades 32 move cooling air through the passages 18 when the rotor assembly 2 is rotating. Cooling air may flow through the passages 18 from one axial end of the rotor core 8 towards the middle of the rotor core and from the other axial end of the rotor core towards the middle of the rotor core - i.e., in opposite directions through the rotor assembly 2. At the middle of the rotor core 8, the cooling air may flow radially inwardly through one or more radially-extending passages (not shown) in the rotor core, and may then flow axially through the annular air gap 62 between the rotor assembly 2 and the stator assembly 50 back towards the end plates 20, 22. Cooling air may be circulated around the rotor assembly 2 in a closed-loop air cooling circuit that includes the passages 18 between the rotor core 8 and the barrel 4, the radially-extending passages in the rotor core 8, and the annular air gap 62 between the rotor assembly 2 and the stator assembly 50. Cooling air may also flow through the passages 18 from one axial end of the rotor core 8 to the other axial end if the fan blades 32 on one of the end plates (e.g., the first end plate 20) are arranged to “push” the cooling air towards the other end plate (e.g., towards the second end plate 22), and the fan blades on the other end plate are arranged to “pull” the cooling air towards it. In this case, the cooling air flows in one direction through the rotor assembly 2. There is no need to provide radially -extending passages in the rotor core 8 to allow cooling air to pass into the annular air gap 62. An alternative air cooling circuit where cooling air flows towards the middle of the annular air gap 62 from the axial ends of the rotor core 8 is described below.

[0171] The mounting members 12 extend past the axial end of the rotor core 8 and may extend so far as to overlap with both sets of fan blades in the axial direction. Using such extended mounting members 12 been found to improve cooling by creating turbulent flow of the cooling air through the passages 18. The mounting members 12 shown do not overlap with the fan blades in the axial direction - see Figures 23a and 23b, for example.

[0172] Referring to Figures 10 and 11, the stator assembly 50 includes a substantially tubular stator pole carrier 52 and a plurality of stator pole modules 54 that are removably mounted to the stator pole carrier 52.

[0173] A body 56 of each stator pole module 54 has a dovetail shaped protrusion 58 on its radially inner surface. The radially outer surface of the stator pole carrier 52 has a plurality of circumferentially-spaced corresponding dovetail shaped recesses 60. Each stator pole module 54 is removably mounted to the stator pole carrier 52 by inserting the dovetail shaped protrusion 58 into one of the dovetail shaped recesses 60 in the stator pole carrier 52. The passages 68 for the cooling liquid described in more detail below are formed in the parts of the body 70 of the stator pole carrier 52 that are located between the dovetail shaped recesses 60. The stator pole modules 54 may move axially relative to the stator pole carrier 52 during an assembly process with the dovetail shaped protrusion 58 of each stator pole module 54 received in its corresponding dovetail shaped recess 60. Movement of the stator pole modules 54 in the radial and circumferential directions is restricted by the complementary engagement profiles of each recess 60 in the stator pole carrier 52 and the protrusion of the corresponding stator pole module.

[0174] The stator pole modules 54 are spaced apart from a radially inner surface of the rotor assembly 2 - e.g., from the permanent magnet modules 16 - by the annular air gap 62.

[0175] Each stator pole module 54 includes a stator coil 64. When the stator pole modules 54 are mounted to the stator pole carrier 52, the stator coils 64 will be electrically interconnected to define a stator winding of the stator assembly, e.g., a three-phase stator winding. The ends of the stator winding are electrically connected to a variable speed drive (not shown) for supplying power to the stator winding to operate the gearless conveyor drive. The variable speed drive (not shown) may be electrically connected to a power network or grid and may be used to control the rotational speed and / or torque of the gearless conveyor drive 1 in a known manner.

[0176] The body 56 of each stator pole module 54 includes an axially-extending passage 66 that extends from one axial end of the stator pole module to the other axial end and is adapted to receive cooling air for directly cooling the stator pole module.

[0177] The stator pole carrier 52 includes a plurality of axially-extending passages 68. Each passage 68 extends between an inlet opening and an outlet opening. The stator pole carrier 52 is made of a suitable metal or metal alloy (e.g., steel or aluminium). The passages 68 for the cooling liquid are formed as bores in the body 70 of the stator pole carrier 52. Such bores may be accurately machined and minimise leakage of cooling liquid into the body 70 of the stator pole carrier 52. Because the cooling liquid flows directly through the stator pole carrier 52, there is improved transfer of heat from the stator coils 64 of the stator pole modules 54 to the cooling liquid. The inlet and outlet openings between which each passage 68 extends are formed in the annular end surfaces of the stator pole carrier 52 as shown in Figures 8 and 9, for example. The inlet and outlet openings are the openings of the axially-extending bores that are formed in the body 70 of the stator pole carrier 52.

[0178] The stator pole carrier 52 shown in Figures 12 and 20a to 23b is cooled by two separate liquid cooling circuits. But it will be understood that different cooling circuit arrangements are possible.

[0179] A first inlet pipe 72 is fluidly connected to an inlet opening of a first (i. e. , upstream) passage of a first liquid cooling circuit 74. The outlet opening of the first passage is fluidly connected to the inlet opening of a second passage of the first liquid cooling circuit 74 by a U-shaped pipe, and the outlet opening of the second passage is fluidly connected to the inlet opening of a third passage of the first liquid cooling circuit by a U-shaped pipe, and so on. The outlet opening of a penultimate passage of the first liquid cooling circuit 74 is fluidly connected to the inlet opening of a last (i.e., downstream) passage of the first liquid cooling circuit by a U-shaped pipe. The outlet opening of the last passage of the first liquid cooling circuit 74 is fluidly connected to a first outlet pipe 76.

[0180] A second inlet pipe 78 is fluidly connected to an inlet opening of a first (i.e., upstream) passage of a second liquid cooling circuit 80. The outlet opening of the first passage is fluidly connected to the inlet opening of a second passage of the second liquid cooling circuit 80 by a U-shaped pipe, and the outlet opening of the second passage is fluidly connected to the inlet opening of a third passage of the second liquid cooling circuit by a U-shaped pipe, and so on. The outlet opening of a penultimate passage of the second liquid cooling circuit 80 is fluidly connected to the inlet opening of a last (i.e., downstream) passage of the second liquid cooling circuit by a U-shaped pipe. The outlet opening of the last passage of the second liquid cooling circuit 80 is fluidly connected to a second outlet pipe 82. The first and second liquid cooling circuits 74, 80 have a zig zag or serpentine construction. The cooling liquid therefore flows through each of the liquid cooling circuits 74, 80 in both axial directions - e.g., in a first direction through some of the passages and in a second, opposite, direction through the other passages.

[0181] It may be seen from Figures 12 and 20a to 23b that the first liquid cooling circuit 74 is arranged to cool one half of the stator pole carrier 52 and that the second liquid cooling circuit 80 is arranged to cool the other half of the stator pole carrier. The first cooling circuit 74 extends from the first inlet pipe 72 to the first outlet pipe 76 and includes twelve passages and eleven U-shaped pipes - five of the U-shaped pipes are at a first axial end of the stator pole carrier 52 and six of the U-shaped pipes are at a second axial end of the stator pole carrier. The second cooling circuit 80 extends from the second inlet pipe 78 to the second outlet pipe 82 and also includes twelve passages and eleven U-shaped pipes - five of the U-shaped pipes are at a first axial end of the stator pole carrier 52 and six of the U-shaped pipes are at a second axial end of the stator pole carrier.

[0182] The first and second inlet pipes 72, 78 and the first and second outlet pipes 76, 82 are fluidly connected to an external cooling circuit (not shown). The external cooling circuit (not shown) may include one or more pumps for circulating the cooling liquid through the first and second cooling circuits 74, 80, and one or more heat exchanges for removing heat from the circulated cooling liquid. In Figure 12, the direction of cooling liquid flow through the first and second cooling circuits 74, 80 is indicated by the arrows.

[0183] The axially-extending passages of each cooling circuit are fluidly connected by U- shaped pipes 84. The first and second inlet pipes 72, 78, the first and second outlet pipes 76, 82, and the intermediate U-shaped pipes are welded to the stator pole carrier 52. This allows for easy detection of the leakage of the cooling liquid by visually inspecting the weld sites at the axial ends of the stator pole carrier 52 and simplifies the assembly process. The various pipes may also be bonded to the stator pole carrier 52, for example. The first and second inlet pipes 72, 78, the first and second outlet pipes 76, 82, and the U-shaped pipes 84 are bent radially inwardly away from the radially outer surface of the stator pole carrier 52 so that they do not obstruct the insertion or removal of the stator pole modules 54.

[0184] In Figure 14, the U-shaped pipes 84 are shown to be connected to optional cooling fins 86. The cooling fins 86 may be located at one or both axial ends of the stator pole carrier 52. The cooling fins 86 shown in Figure 14 are annular, but other designs are possible. The cooling fins 86 are adapted to transfer heat from the cooling liquid to the cooling air that is circulated around the air cooling circuit.

[0185] The stator assembly 50 includes a support shaft 88 that supports the stator assembly 50 and the rotor assembly 2. In particular, the end plates 20, 22 of the rotor assembly 2 are mounted to the support shaft 88 by bearings 90, 92.

[0186] The support shaft 88 includes a central shaft part 94 and a plurality of circumferentially- spaced radially-extending ribs 96. The stator pole carrier 52 is mounted on the ribs 96, e.g., welded or bonded to the radially outer face of each rib. The stator pole carrier 52 may also be an interference fit on the ribs 96. The ribs 96 define a mounting part of the support shaft 88.

[0187] The central shaft part 94 extends axially beyond the first and second end plates 20, 22 and is supported at both axial ends by a respective stationary support structure 200, 202. A plurality of axially-extending passages 98 are provided between the central shaft part 94 and the mounted stator pole carrier 52 and are adapted to receive cooling air for cooling the stator assembly. Each passage 98 in the support shaft is defined between an adjacent pair of radial ribs 96.

[0188] A bore 100 in the central shaft part 94 provides a passage for the first and second inlet pipes 72, 78 and the first and second outlet pipes 76, 82. The bore 100 may also provide a passage for electrical cables, e.g., for electrically connecting the stator winding to an external variable speed drive (not shown).

[0189] The stator assembly 50 is also cooled by the air cooling circuit. In particular, cooling air is circulated by the fan blades 32 provided on the inner surface of each of the end plates 20, 22. The fan blades 32 are adapted to move cooling air through the air cooling circuit for cooling the stator assembly 50 when the rotor assembly 2 is rotating.

[0190] Cooling air may flow through the annular air gap 62 between the stator assembly 50 and the rotor assembly 2 from one axial end of the stator pole carrier 52 towards the middle of the stator pole carrier and from the other axial end of the stator pole carrier towards the middle of the stator pole carrier - i.e., in opposite directions. At an intermediate location between the axial ends of the stator pole carrier 52, typically at or near the middle of the stator pole carrier in the axial direction, the cooling air may flow radially inwardly through one or more radially -extending passages (not shown) in the stator pole carrier 52 and may then flow axially through the passages 96 between the central shaft part 94 and the radially inner surface of the stator pole carrier 52 back towards the end plates 20, 22. In one arrangement, shown in Figures 18 and 19, the stator pole carrier is provided in two parts 52a, 52b separated in the axial direction by a gap 102 through which the cooling air may flow, i.e., the stator assembly 50 may have a split stator pole carrier. The first part 52a of the stator pole carrier includes a plurality of axially-extending passages 68a formed in a body 70a and a plurality of dovetail shaped recesses 14a. Similarly, the second part 52b of the stator pole carrier includes a plurality of axially-extending passages 68b formed in a body 70b and a plurality of dovetail shaped recesses 14a. The dovetail shaped recesses 14a, 14b in the first and second parts 52a, 52b of the stator pole carrier are aligned as shown so that each stator pole module 54 is received in one of the recesses 14a in the radially outer surface of the first part 52a and in an aligned one of the recesses 14b in the radially outer surface of the second part 52b. The split stator pole carrier may be cooled by any suitable liquid cooling circuit(s). For example, an outlet opening of a passage 68a in the first part 52a may be fluidly connected by a pipe to an inlet opening of a passage 68b in the second part 52b and vice versa. In this case, cooling air flowing through the gap 102 would flow past the pipes. U-shaped pipes like those shown in Figure 12 to 14 may be used to fluidly connected outlet and inlet openings at the axial ends of the split stator pole carrier.

[0191] The gap 102 may be aligned with a radially-extending passage (not shown) in the body 56 of each stator pole module 54. The radially-extending passage (not shown) in the body 56 of each stator pole module 54 is in fluid communication with the axially- extending passage 66. Cooling air may therefore flow through the axially-extending passage 66 of each stator pole module 54 from one axial end of each stator pole module towards the middle of the body 56 and from the other axial end of each stator pole module towards the middle of the body 56 - i.e., in opposite directions. At an intermediate location between the axial ends of each stator pole module 54, typically at or near the middle of each stator pole module, the cooling air may flow radially inwardly through the radially -extending passage (not shown) in each stator pole module 54 and then through the gap 102 between the two parts 52a, 52b of the split stator pole carrier.

[0192] The rotor assembly 2 includes a brake disc 34. In particular, the brake disc 34 is formed as part of the rigid structural tube 6 and extends radially outwardly. The brake disc 34 may be used for emergency braking of the gearless conveyor drive 1 and / or to keep the rotor assembly 2 stationary during maintenance or repair, for example. The brake disc 34 may form part of an external braking assembly (not shown) having any suitable construction.

[0193] A suitable friction coating may be applied to one or both of the annular surfaces of the brake disc 34.

[0194] Figures 26A and 26B show the radially-extending flange 24 of the tube 6 and the brake disc 34. Figure 26A shows one of the fixing openings 28 in the flange 24 that is aligned with a corresponding fixing opening 30 in the first end plate 20. (In both Figures 26A and 26B the first end plate 20 has been omitted for clarity.) Figure 26B shows one of a plurality of circumferentially-spaced fixing openings 36 in the flange 24. The brake disc 34 is removably mounted to the tube 6 and includes a plurality of circumferentially- spaced fixing opening 38. The respective fixing openings 36, 38 in the flange 24 and the brake disc 34 are aligned to receive bolts to removably mount the brake disc to the tube 6. In this arrangement, the brake disc 34 is removed towards the right, which may require the conveyor belt CB to be removed. The flange 26 at the other axial end of the tube 6 will also prevent the removal of the brake disc 34 unless it is segmented - i.e., formed from a plurality of brake disc segments. Figures 27A and 27B show an alternative arrangement where the brake disc 34 is removed towards the left. Such a brake disc 34 does not need to be segmented. Figure 27A shows one of the fixing openings 28 in the flange 24 that is aligned with a corresponding fixing opening 30 in the first end plate 20. (In both Figures 27A and 27B the first end plate 20 has been omitted for clarity.) Figure 27B shows one of a plurality of circumferentially-spaced fixing openings 36 in the flange 24. The brake disc 34 is removably mounted to the tube 6 and includes a plurality of circumferentially-spaced fixing opening 38. The respective fixing openings 36, 38 in the flange 24 and the brake disc 34 are aligned to receive bolts to removably mount the brake disc to the tube 6.

[0195] The brake disc 34 includes a plurality of circumferentially-spaced locking holes 40 adapted to receive a locking pin of an external locking mechanism (not shown). The locking pin may be moved in the axial direction between a locking position where it is engaged in an aligned locking hole 40 and a non-locking position where it is not engaged and the rotor assembly 2 is free to rotate. When the locking pin is engaged in a locking hole 40, the rotor assembly 2 is prevented from rotating by the locking mechanism. This may be necessary when the gearless conveyor drive 1 is undergoing maintenance or repair, for example.

[0196] The brake disc 34 may be a vented brake disc and include a plurality of vent holes or vent openings 42 - see Figure 28. The vent holes or vent openings 42 may be arranged in any suitable pattern.

[0197] An alternative barrel 104 is shown in Figures 29 to 31. The barrel 104 is similar to the barrel described above but includes an integral brake disc 108. In particular, the brake disc 108 is forged as part of the rigid structural tube 106. The brake disc may also be welded or shrink-fitted to the barrel, for example.

[0198] Figure 32A shows an alternative barrel 110 that is similar to the barrel described above but includes a “floating” brake disc 112. The “floating” brake disc 112 is a light interference fit to the rigid structural tube 114 to maintain concentricity. The “floating” brake disc 112 is fixedly connected to the tube 114 by one or more mechanical fixings that are spaced circumferentially around the barrel and allow for some limited relative movement between the brake disc and the tube 114. The mechanical fixings may be bobbins with a circular cross-section and a single bobbin 116 is shown in Figure 32A. The bobbins 116 may have any suitable single- or multi-piece construction. Some suitable bobbins 116 are shown in Figures 32B to 32F.

[0199] Cut-out portions 120 may be provided to reduce the contact area between the “floating” brake disc 112 and the tube 114 - see Figure 33. The cut-out portions 120 may have rounded comers and are spaced circumferentially around the barrel 110.

[0200] The mechanical fixings may be keys 118 with a square cross-section and a single key 118 is shown in Figure 34. The key 118 shown in Figure 34 has a single-piece construction, but it will be understood that the keys may also have a multi-piece construction.

[0201] The “floating” brake disc 112 may be a vented brake disc and include a plurality of vent holes or vent openings 122 - see Figure 35. The vent holes or vent openings 122 may be arranged in any suitable pattern.

[0202] The support structures 200, 202 shown in Figures 1 and 2 are designed to hold the support shaft 88 stationary during normal operation of the gearless conveyor drive 1.

[0203] Both axial ends of the central shaft part 94 have a D-shaped cross-section and are received in a D-shaped opening in a respective support structure 200, 202. A lower part of each D-shaped opening is defined by a lower section 204 of each support structure 200, 202 and an upper part of each D-shaped opening is defined by an upper section 206 of each support structure. The upper section 206 of each support structure 200, 202 is removably mounted to the lower section 204 by bolts.

[0204] With the upper section 206 of each support structure 200, 202 removed, the axial ends of the support shaft 88 may be received in the lower part of the D-shaped opening. The upper section 206 of each support structure 200, 202 may then be reconnected to the lower section 204 to retain the support shaft 88 in the D-shaped opening and hold it stationary. The rotor assembly 2 is supported on the support shaft 88 by the bearings 90, 92 with sufficient clearance between the brake disc 34 and the ground or foundation on which the support structures 200, 202 are positioned. This allows for unobstructed rotation of the rotor assembly 2 relative to the stator assembly 50 and the stationary support structures 200, 202.

[0205] It will be understood that some of the stator pole modules 54 will be axially aligned with the support structures. For the support structures 200, 202 shown in Figures 1 and 2, for example, this would include some of the stator pole modules 54 that extend around the lower part of the stator pole carrier 52. Because these stator pole modules 54 are obstructed by the support structures 200, 202 they cannot be easily removed from the stator pole carrier 52 if they develop a fault, for example.

[0206] Figures 36 to 40 show alternative support structures 300, 302 for the gearless conveyor drive 1. Each support structure 300, 302 includes a lower section 304, an upper section 306 that supports an axial end of the support shaft 88, and an intermediate section 308 between the lower section 304 and the upper section 306.

[0207] The intermediate section 308 is axially aligned with a plurality of stator pole modules 54 (so-called “aligned stator pole modules”).

[0208] The upper section 306 of each support structure 300, 302 defines an opening with a square-shaped cross-section. In other words, both axial ends 88a, 88b of the support shaft 88 have a square-shaped cross-section and are received in a square-shaped opening in a respective support structure 300, 302. It will be understood that other cross-sections are possible, e.g., the D-shaped cross-section described above.

[0209] The intermediate section 308 of each support structure 300, 302 includes three removable members 310, 312 and 314 that are adapted to be selectively removable from the remainder of the support structure. Removing each of the removable members 310, 312 and 314 creates an opening or void in the support structure 300, 302 that is sized and shaped to allow at least a selected one of the aligned stator pole modules to be removed from the stator pole carrier in the axial direction through the opening. The support structures 300, 302 are constructed so that all of the aligned stator pole modules that would otherwise be obstructed by the support structure may be removed from the stator pole carrier in the axial direction by removing at least one of the removable members 310, 312, 314 of a support structure.

[0210] Each removable member 310, 312 and 314 is removably mounted or connected to the remainder of the support structure, e.g., to one or both of the lower and upper sections 304, 306, and optionally to another removable member, using bolts.

[0211] The outer removable members 310, 314 are spaced apart from the central removable member 312 by gaps 316 that may optionally be filled with one or more shim packs.

[0212] If a selected one of the aligned stator pole modules 54 needs to be removed from the stator pole carrier 52, e.g., because it is faulty and needs to be repaired, a particular removable member 310, 312, 314 may be removed from the support structure 300 (or the support structure 302) to create an opening or void that is aligned with the faulty stator pole module and through which the faulty stator pole module may be removed. A replacement stator pole module may also be inserted into the stator pole carrier 52 through the same opening.

[0213] Figure 38 shows the support structure 300 with the central removable member 312 removed to create a central opening 318 in the support structure. The opening 318 would allow one or more of the three stator pole modules 54d, 54e and 54f that are axially aligned with the central removable member 312 to be removed from the stator pole carrier 52. Figure 39 shows the support structure 300 with the removable member 314 removed to create an opening 320 in the support structure. The opening 320 would allow one or more of the three stator pole modules 54g, 54h and 54i that are axially aligned with the removable member 314 to be removed from the stator pole carrier 52. Figure 40 shows the support structure 300 with the removable member 310 removed to create an opening 322 in the support structure. The opening 322 would allow one or more of the three stator pole modules 54a, 54b and 54c that are axially aligned with the removable member 310 to be removed from the stator pole carrier 52. Any of the nine aligned stator pole modules 54a, 54b, ..., 54i may therefore be removed from the stator pole carrier by removing the appropriate removable member 310, 312 and 314 to create an aligned opening in the intermediate section 308 of the support structure 300.

[0214] Each end plate 20, 22 includes four circumferentially-spaced access openings 44. Each access opening 44 is aligned with the stator pole modules 54 - i.e., positioned at the same radial distance from the rotation axis of the rotor assembly 2 as the stator pole modules. Each access opening 44 is covered by a removable cover 46. To remove the selected one of the aligned stator pole modules 54, the rotor assembly 2 is rotated until an access opening 44 in the end plate 20 is aligned with the stator pole module 54 to be removed. The removable member 310, 312 or 314 of the support structure 300 is removed to create the opening or void in the support structure 300, and the stator pole module 54 is removed in the axial direction through the aligned openings in the end plate 20 and the support structure 300. The access openings 44 in the end plate 20 are sized and shaped to correspond generally to the size and shape of the openings created in the support structure when one of the removable members 310, 312 and 314 is removed. The rotor assembly 2 may be rotated before or after the removable member 310, 312 or 314 is removed from the support structure 300 to create the opening or void in the support structure.

[0215] It will be understood that the access openings 44 in the end plates 20 are also used to remove a stator pole module 54 that is not obstructed by the support structure 300 - for example, a stator pole module that is located on a side part or on the upper part of the stator pole carrier 52. In this case, the rotor assembly 2 may be rotated until an access opening 44 in the end plate 20 is aligned with the stator pole module 54 to be removed. The stator pole module 54 is then removed in the axial direction through the access opening 44 in the end plate 20.

[0216] Both of the support structures 300, 302 have the same construction so that a stator pole module 54 may be removed from both axial ends of the barrel 4. Access openings 44 are also provided in both of the end plates 20, 22. Other constructions are possible, including those where a stator pole module can only be removed from one axial end of the barrel.

[0217] Figures 41 to 44 show alternative support structures 400, 402.

[0218] In this arrangement, the gearless conveyor drive 1 is selectively reconfigurable between a first configuration where the support shaft 88 may not rotate relative to the support structures 400, 402 (i.e., where the support shaft is held stationary), and a second configuration where the support shaft and the mounted stator pole carrier 52 may rotate relative to the support structures. The first configuration may be when the gearless conveyor drive 1 is operating normally. The second configuration may during a stator pole module removal and / or insertion operation.

[0219] The support structures 400, 402 are designed to hold the support shaft 88 stationary during normal operation of the gearless conveyor drive 1.

[0220] Both axial ends 88a, 88b of the central shaft part 94 have a D-shaped cross-section and are received in a D-shaped opening in a respective support structure 400, 402. A lower part of each D-shaped opening is defined by a lower section 404 of the support structure 400, 402 and an upper part of each D-shaped opening is defined by an upper section 406 of the support structure. The upper section 406 of each support structure 400, 402 is removably mounted to the lower section 404 by bolts. When the upper section 406 of each support structure 400, 402 is fixedly connected to the lower section 404, the support shaft 88 cannot rotate. In particular, rotation of the support shaft 88 relative to the support structures 400, 402 is mechanically prevented by the contacting flat surfaces of the support shaft 88 and the upper section 406. However, if the upper section 406 is removed from the lower section 404 - e.g., by removing the bolts and then removing the upper section - the support shaft 88 may rotate relative to the support structures 400, 402. The axial ends 88a, 88b of the support shaft 88 are supported for relative rotation by the arcuate surface in the lower section 404 of each support structure 400, 402. Relative rotation is therefore possible as long as the upper section 406 is removed. The upper section 406 of each support structure 400, 402 therefore functions as a locking mechanism. When the upper section 406 of each support structure 400, 402 is fixedly connected to the respective lower section 404, the gearless conveyor drive 1 is in the first configuration, and when the upper sections 406 are removed, the gearless conveyor drive is in the second configuration.

[0221] Relative rotation is also prevented by a removable key. As shown in Figure 41 to 44, a key way 408 is defined by an axially-extending recess formed in a surface of the support structure 400 and another key way 410 is defined by an axially-extending recess in the surface of the axial end 88a of the support shaft 88 that faces the support structure surface. When a removable key (not shown) is received in the aligned keyways 408, 410, rotation of the support shaft 88 relative to the support structures 400, 402 is prevented. Otherwise, when the key is not received in the aligned key ways 408, 410, rotation of the support shaft 88 relative to the support structures 400, 402 is permitted.

[0222] Figures 42 and 43 show how the upper section 406 of the support structures 400, 402 may be removed and a tool 412 fitted to an axial end 88a of the support shaft 88. In particular, the axial end 88a of the support shaft 88 includes non-circular mating fixture 414 that is received in a corresponding mating opening 416 in the tool 412. The tool 412 may also be bolted to the support shaft 88 using aligned fixing openings 418, 420 in the tool 412 and the axial end 88a of the support shaft 88. Figure 44 shows how the support shaft 88 and the stator pole carrier 52 may be rotated through a sufficient angle so that a faulty stator pole module 54 is no longer obstructed by the support structure 400 and may be removed from the stator pole carrier 52 in the axial direction. In Figure 44, the rotation of the support shaft 88 is indicated by the arrow labelled “A”. A replacement stator pole module (not shown) may also be inserted into the stator pole carrier 52.

[0223] Rotation of the support shaft 88 is preferably prevented while a stator pole module 54 is being removed or installed. The support shaft 88 and the stator pole carrier 52 may then be rotated back to the initial position and the upper section 406 of each support structure 400, 402 may be fixedly reconnected to the lower section 404.

[0224] The key (not shown) is removed from the aligned key ways 408, 410 in the support structure 400 and the support shaft 88 before the shaft is rotated and then inserted back into the aligned key ways afterwards. The key ways 408, 410 may be used as a guide when rotating the support shaft 88 back to its normal position - i.e., rotation may be stopped when the respective key ways are aligned.

[0225] The rotor assembly 2 is rotated until an access opening 44 in the end plate 20 is aligned with the stator pole module to be removed. In Figure 44, the rotation of the rotor assembly 2 is indicated by the arrow labelled “B” In Figure 40 the stator pole module 54 is shown being removed in the axial direction through the aligned access opening 44 in the end plate 20. It will be understood that the access openings 44 in the end plates 20 are also used to remove a stator pole module 54 that is not obstructed by the support structure 400. In this case, the rotor assembly 2 may be rotated until an access opening 44 in the end plate 20 is aligned with the stator pole module 54 to be removed. The stator pole module 54 is then removed in the axial direction through the access opening 44 in the end plate 20.

[0226] Both of the support structures 400, 402 have the same construction so that a stator pole module 54 may be removed from both axial ends of the barrel 4. Access openings 44 are also provided in both of the end plates 20, 22. Other constructions are possible, including those where a stator pole module can only be removed from one axial end of the barrel.

Claims

CLAIMS1. A gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive (1) comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB), and a rotor core (8) mechanically mounted to a radially inner surface (4b) of the barrel (4), wherein a plurality of axially-extending passages (18) is provided between the radially inner surface (4a) of the barrel (4) and a radially outer surface (8b) of the rotor core (8) and adapted to receive cooling air for cooling the rotor assembly (2).

2. A gearless conveyor drive (1) according to claim 1, wherein the passages (18) are circumferentially-spaced around the radially outer surface (8b) of the rotor core (8).

3. A gearless conveyor drive (1) according to claim 1 or claim 2, wherein the rotor core (8) is mechanically mounted to the barrel (4) by a plurality of circumferentially- spaced mounting members (12), and wherein each passage (18) is defined between an adjacent pair of mounting members (12).

4. A gearless conveyor drive (1) according to claim 3, wherein each mounting member (12) is fixedly connected to, or integral with, the radially inner surface (4b) of the barrel (4).

5. A gearless conveyor drive (1) according to claim 3 or claim 4, wherein each mounting member (12) extends axially along the radially inner surface (4b) of the barrel (4).

6. A gearless conveyor drive (1) according to any of claims 3 to 5, wherein the rotor core (8) comprises a plurality of segments (10), each rotor core segment (10) being mechanically mounted to the barrel (4) by one or more of the mounting members (12).

7. A gearless conveyor drive (1) according to claim 6, wherein each mounting member (12) has an engagement profile and the radially outer surface (10b) of eachrotor core segment (10) has a corresponding engagement profile (14) such that the rotor core segments (10) are removably mounted to the barrel (4) by the mounting members (12).

8. A gearless conveyor drive (1) according to any of claims 3 to 5, wherein the rotor core is an interference fit on the mounting members.

9. A gearless conveyor drive (1) according to any of claims 3 to 8, wherein the mounting members (12) are made of a non-magnetic material.

10. A gearless conveyor drive (1) according to any preceding claim, wherein the rotor core (8) has a laminated construction.

11. A gearless conveyor drive (1) according to any preceding claim, wherein the rotor assembly (2) further comprises a plurality of circumferentially-spaced permanent magnet modules (16) on a radially inner surface (8a) of the rotor core (8).

12. A gearless conveyor drive (1) according to any preceding claim, wherein the rotor assembly (2) further comprises a pair of end plates (20, 22), each end plate (20, 22) being located at an axial end of the barrel (4) and adapted to rotatably mount the rotor assembly (2).

13. A gearless conveyor drive (1) according to claim 12, wherein at least one of the end plates (20, 22) comprises one or more fan blades (32) on its inner surface, the fan blades (32) being adapted to move cooling air through the axially-extending passages (18).

14. A gearless conveyor drive (1) according to any of claims 3 to 9, wherein the rotor assembly (2) further comprises a pair of end plates (20, 22), each end plate (20, 22) being located at an axial end of the barrel (4) and adapted to rotatably mount the rotor assembly (2), wherein at least one of the end plates (20, 22) comprises one or more fan blades (32) on its inner surface, the fan blades (32) being adapted to movecooling air through the axially-extending passages (18), and wherein each mounting member (12) extends past the axial end of the rotor core (8) facing the fan blades (32) and overlaps with the one or more fan blades (32) in the axial direction.

15. A gearless conveyor drive (1) according to any preceding claim, wherein the barrel (4) comprises a rigid structural tube (6) whose radially inner surface (6b) defines the radially inner surface (4a) of the barrel (4), and wherein the radially outer surface (4a) of the barrel (4) is defined by the radially outer surface (6a) of the tube (6) or by an outer layer that is adhered to the radially outer surface (6a) of the tube (6).

16. A gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive (1) comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB); and a stator assembly (50) radially inside the rotor assembly (2), the stator assembly (50) comprising a substantially tubular stator pole carrier (52) and a plurality of stator pole modules (54) that are removably mounted to the stator pole carrier (52), wherein the stator pole carrier (52) comprises a plurality of axially-extending passages (68), each passage (68) extending between an inlet opening and an outlet opening, and wherein the inlet and outlet openings are fluidly connected by a plurality of pipes (84) such that the passages (68) and the pipes (84) define one or more liquid cooling circuits adapted to receive cooling liquid for cooling the stator assembly.

17. A gearless conveyor drive (1) according to claim 16, wherein the rotor assembly (2) further comprises a pair of end plates (20, 22), each end plate (20, 22) being located at an axial end of the barrel (4) and adapted to rotatably mount the rotor assembly (2).

18. A gearless conveyor drive (1) according to claim 17, wherein at least one of the end plates (20, 22) comprises one or more fan blades (32) on its inner surface, the fan blades (32) being adapted to move cooling air through one or more air cooling circuits of the gearless conveyor drive (1) for cooling the stator assembly (50).

19. A gearless conveyor drive (1) according to any of claims 16 to 18, wherein each stator pole module (54) has an engagement profile (58) and the radially outer surface of the stator pole carrier (52) has a plurality of circumferentially-spaced corresponding engagement profiles (60) such that the stator pole modules (54) are removably mounted to the stator pole carrier (52) by the respective engagement profiles (58, 60).

20. A gearless conveyor drive (1) according to any of claims 16 to 19, wherein each stator pole module (54) comprises a stator coil (64) and an axially -extending passage (66) that extends from one axial end of the stator pole module (54) to the other axial end and is adapted to receive cooling air for cooling the stator pole module (54).

21. A gearless conveyor drive (1) according to any of claims 16 to 20, wherein the one or more liquid cooling circuits have one or more cooling circuit inlets (72, 78), and one or more cooling circuit outlets (76, 82) fluidly connected to the one or more cooling circuit inlets (72, 78) for re-circulation of the cooling liquid.

22. A gearless conveyor drive (1) according to any of claims 16 to 21, wherein the inlet and outlet openings are formed in annular end surfaces of the stator pole carrier (52).

23. A gearless conveyor drive (1) according to any of claims 16 to 22, wherein the pipes (84) are fixedly connected to the stator pole carrier (52), e.g., by welding or bonding.

24. A gearless conveyor drive (1) according to any of claims 16 to 23, wherein the pipes (84) are connected to one or more cooling fins (86).

25. A gearless conveyor drive (1) according to any of claims 16 to 24, wherein the stator assembly (50) further comprises a shaft (88).

26. A gearless conveyor drive (1) according to claim 25, wherein the shaft (88) comprises a central shaft part (94), and a mounting part (96) that is displaced radiallyoutwardly from the central shaft part (94) and on which the stator pole carrier (52) is mounted.

27. A gearless conveyor drive (1) according to claim 26, wherein a plurality of axially-extending passages (98) is provided between the central shaft part (94) and the stator pole carrier (52) and adapted to receive cooling air for cooling the stator assembly (50).

28. A gearless conveyor drive (1) according to claim 27, wherein a plurality of circumferentially-spaced ribs (96) extend radially outwardly from the central shaft part (94) and define the mounting part, and wherein each passage (98) between the central shaft part (94) and the stator pole carrier (52) is defined between an adjacent pair of radial ribs (96).

29. A method of cooling a gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive (1) comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB); and a stator assembly (50) radially inside the rotor assembly (2), the stator assembly (50) comprising a substantially tubular stator pole carrier (52) and a plurality of stator pole modules (54) that are removably mounted to the stator pole carrier (52), wherein the stator pole carrier (52) comprises a plurality of axially-extending passages (68), each passage extending between an inlet opening and an outlet opening, and wherein the inlet and outlet openings are fluidly connected by a plurality of pipes (84) such that the passages (68) and the pipes (84) define one or more liquid cooling circuits; the method comprising passing cooling liquid through the one or more liquid cooling circuits to cool the stator assembly (50).

30. A method according to claim 29, further comprising passing cooling air through one or more passages in the stator assembly (50) and / or through the annular air gap (62) between the stator assembly (50) and the rotor assembly (2) to cool the stator assembly31. A gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB), and a rotor core (8) mechanically mounted to a radially inner surface (4b) of the barrel (4), wherein the barrel (4) further comprises a radially-extending brake disc (34; 34').

32. A gearless conveyor drive (1) according to claim 31, wherein the barrel (4) comprises a rigid structural tube (6).

33. A gearless conveyor drive (1) according to claim 31 or claim 32, wherein the brake disc (34') is one of forged, welded and shrink-fitted to the barrel (4).

34. A gearless conveyor drive (1) according to claim 31 or claim 32, wherein the brake disc (34) is removably mounted to the barrel (4) by one or more mechanical fixings.

35. A gearless conveyor drive (1) according to claim 34, wherein the barrel comprises a radially-extending flange (24) and the brake disc (34) is removably mounted to the flange (24) by the one or more mechanical fixings.

36. A gearless conveyor drive (1) according to claim 34 or claim 35, wherein the brake disc (112) is a “floating” brake disc and the one or more mechanical fixings (116, 118) allow for relative movement between the brake disc (112) and the barrel (114).

37. A gearless conveyor drive (1) according to any of claims 31 to 36, wherein the brake disc (34) comprises one or more locking holes (40) adapted to receive a locking pin of a locking mechanism.

38. A gearless conveyor drive (1) according to any of claims 31 to 37, wherein the brake disc (34) is a vented bake disc and comprises one or more vent holes or vent openings (42).

39. A gearless conveyor drive (1) according to any of claims 31 to 38, wherein the brake disc (34) is at an axial end of the barrel (4).

40. A gearless conveyor drive (1) according to claim 39, further comprising a second brake disc at the other axial end of the barrel.

41. A gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive (1) comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB); and a stator assembly (50) radially inside the rotor assembly (2), the stator assembly (50) comprising: a substantially tubular stator pole carrier (52) and a plurality of stator pole modules (54) that are removably mounted to the stator pole carrier (52), and a stationary shaft (88) on which the stator pole carrier (52) is mounted; and a pair of support structures (300, 302), each support structure (300, 302) supporting a respective axial end (88a, 88b) of the stationary shaft (88); wherein at least one of the support structures (300, 302) comprises a lower section (304), an upper section (306) that supports the axial end (88a, 88b) of the stationary shaft (88), and an intermediate section (308) between the lower section (304) and the upper section (306) and that is axially aligned with one or more of the stator pole modules (54); and wherein the intermediate section (308) of the at least one of the support structures (300, 302) comprises at least one removable member (310, 312, 314) adapted to be selectively removable from the remainder of the support structure to thereby create an opening (318, 320, 322) in the support structure (300, 302) that is sized and shapedto allow at least a selected one of the aligned stator pole modules (54) to be removed from the stator pole carrier (52) in the axial direction through the opening (318, 320, 322).

42. A gearless conveyor drive (1) according to claim 41, wherein the intermediate section (302) comprises two or more removable members (310, 312, 314), each removable member (310, 312, 314) adapted to create a respective opening (318, 320, 322) in the support structure (300, 302) when removed from the remainder of the support structure (300, 302).

43. A gearless conveyor drive (1) according to claim 41 or claim 42, wherein each removable member (310, 312, 314) is removably mounted to the remainder of the support structure (300, 302), and optionally to another removable member, by one or more mechanical fixings.

44. A gearless conveyor drive (1) according to any of claims 41 to 43, wherein the lower section (304) of the support structure (300, 302) defines a footplate for mounting the support structure (300, 302).

45. A gearless conveyor drive (1) according to any of claims 41 to 44, wherein the upper section (306) of the support structure (300, 302) comprises an opening having a non-circular cross-section for receiving the axial end (88a, 88b) of the stationary shaft (88), the axial end (88a, 88b) of the stationary shaft (88) having a corresponding noncircular cross-section.

46. A gearless conveyor drive (1) according to any of claims 41 to 45, wherein the rotor assembly (2) further comprises a pair of end plates (20, 22), each end plate (20, 22) being located at an axial end of the barrel (4) and adapted to rotatably mount the rotor assembly (2).

47. A gearless conveyor drive (1) according to claim 46, wherein at least one of the end plates (20, 22) comprises one or more access openings (44), each access opening (44) being aligned with the stator pole modules (54).

48. A gearless conveyor drive (1) according to claim 47, wherein each access opening (44) is covered by a removable cover (46).

49. A gearless conveyor drive (1) for driving a conveyor belt (CB) of a conveyor system, the gearless conveyor drive (1) comprising: a rotor assembly (2) comprising a substantially tubular barrel (4) having a radially outer surface (4a) adapted to contact the conveyor belt (CB); a stator assembly (50) radially inside the rotor assembly (2), the stator assembly (50) comprising: a substantially tubular stator pole carrier (52) and a plurality of stator pole modules (54) that are removably mounted to the stator pole carrier (52), and a shaft (88) on which the stator pole carrier (52) is mounted; and a pair of support structures (400, 402), each support structure (402, 44) supporting a respective axial end (88a, 88b) of the shaft (88); wherein the gearless conveyor drive (1) is selectively reconfigurable between a first configuration where the shaft (88) may not rotate relative to the support structures (400, 402) and a second configuration where the shaft (88) and the mounted stator pole carrier (52) may rotate relative to the support structures (400, 402).

50. A gearless conveyor drive (1) according to claim 49, wherein at least one of the support structures (400, 402) comprises a lower section (404) and an upper section (406) that are removably mounted to each other, wherein the lower and upper sections (404, 406) each define part of a D-shaped opening, and wherein the axial end (88a, 88b) of the shaft (88) that is supported by the support structure (400, 402) has a corresponding D-shaped cross-section with an arcuate lower surface that is in contact with, and is supported by, a corresponding supporting arcuate surface of the lower section (404), and a flat upper surface that is in contact with a corresponding flat surfaceof the upper section (406) when the gearless conveyor drive (1) is in the first configuration so that the shaft (88) may not rotate relative to the support structures (400, 402).

51. A gearless conveyor drive (1) according to claim 50, wherein the upper section (406) of the at least one of the support structure (400, 402) is adapted to be removed from the lower section (404) when the gearless conveyor drive (1) is in the second configuration so that the shaft (88) and the stator pole carrier (52) may rotate relative to the support structures (400, 402).

52. A gearless conveyor drive (1) according to any of claims 49 to 51, wherein at least one of the support structures (400, 402) and the supported axial end (88a) of the shaft (88) both comprise a key way (408, 410) into which a removable key is adapted to be inserted when the respective key ways (408, 410) are radially aligned.

53. A gearless conveyor drive (1) according to claim 52, wherein one key way (408) is defined by an axially-extending recess formed in a surface of the support structure (400) and the other key way (410) is defined by an axially -extending recess formed in the axial end (88a) of the shaft (88).

54. A gearless conveyor drive (1) according to claim 53, wherein at least one of the end plates (20, 22) comprises one or more access openings (44), each access opening (44) being aligned with the stator pole modules (54).

55. A gearless conveyor drive (1) according to claim 54, wherein each access opening (44) is covered by a removable cover (46).

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