WO2022253498A1

WO2022253498A1 - Turas drive and tracked vehicle with turas drive

Info

Publication number: WO2022253498A1
Application number: PCT/EP2022/061384
Authority: WO
Inventors: Bernward Welschof
Original assignee: Bernward Welschof
Priority date: 2021-05-31
Filing date: 2022-04-28
Publication date: 2022-12-08
Also published as: JP2024525107A

Abstract

The invention relates to a turas drive (1) comprising a drive motor (2), a reduction gear (3) driven by the drive motor (2) and a hub (6), in particular a turas wheel (4), driven by the reduction gear (3). The drive motor (2) is designed as an electric motor (12), wherein a rotor shaft (16) of the electric motor (12) connected to a rotor (15) of the electric motor (12) is arranged coaxially with an input shaft (11) of the reduction gear (3) and the electric motor (12) is provided with a liquid cooling system for cooling, which comprises a cooling fluid circuit.

Description

description

Turas drive and tracked vehicle with Turas drive

The invention relates to a sprocket drive comprising a drive motor, a reduction gear driven by the drive motor and a hub, in particular a sprocket wheel, driven by the reduction gear.

Sprocket drives are used in tracked or caterpillar vehicles, for example in mobile construction machines such as excavators, bulldozers, mobile caterpillar work platforms, mobile caterpillar drills or dampers.

Up until now, sprocket drives for tracked vehicles have had a hydraulic motor as the drive motor. Due to the high power density of hydraulic motors and their compact dimensions, sprocket drives with a drive motor designed as a hydraulic motor allow the crawler vehicle to have a high ground clearance and a corresponding passage between a left and right sprocket drive of the tracked vehicle or crawler vehicle. High ground clearance and a correspondingly large passage between a left and right sprocket drive of the tracked or tracked vehicle is imperative for tracked or tracked vehicles designed as mobile construction machines that are used on construction sites and off-road due to good off-road mobility.

In the case of small tracked or caterpillar vehicles, for example mini excavators or mini dampers or small mobile caterpillar work platforms or small mobile caterpillar drills that are used for a limited time in urban areas with limited power requirements, replacing an internal combustion engine drive with an electric, especially battery-electric drive is necessary due to increasing emissions regulations , drive desired. For small tracked or caterpillar vehicles with a battery-electric drive, it is possible to meet the requirements for ground clearance and passage between a left and right sprocket drive of the tracked or caterpillar vehicle to use compact sprocket drives with hydraulic motors as drive motors, which are driven by a electric driven hydraulic pump are supplied with pressure medium. However, such a battery-electric drive concept causes a high construction cost.

The present invention is based on the object of providing a sprocket drive for an electrically, in particular battery-electrically operated, tracked or caterpillar vehicle which has compact dimensions and low construction costs.

This object is achieved according to the invention in that the drive motor is designed as an electric motor, with a rotor shaft of the electric motor connected to a rotor of the electric motor being arranged coaxially to an input shaft of the reduction gear and the electric motor being provided with liquid cooling for cooling, which comprises a cooling fluid circuit.

The idea according to the invention consists in using a liquid-cooled electric motor as the drive motor of the door drive, the liquid cooling of which comprises a cooling fluid circuit. The cooling fluid circuit preferably circulates a cooling fluid between a pump and a heat exchanger. An electric motor cooled by liquid cooling, which includes a cooling fluid circuit, can be operated with high electrical currents. The liquid cooling thus makes it possible to increase the continuous torque of the electric motor. Since with liquid cooling the heat is no longer dissipated to the environment - as with air cooling - via internal heat conduction/heat radiation/heat transfer to poorly ventilated surfaces of the electric motor, but is accomplished via the much more effective heat transport via mass transport of the cooling liquid, acceptable Steady-state temperatures are guaranteed despite the significantly increased current density. The liquid cooling thus makes it possible to reduce the dimensions of the electric motor of the sprocket drive and to generate a high torque with an electric motor that is compact in terms of dimensions, in particular the axial and/or radial dimensions. Such a compact, liquid-cooled electric motor can be arranged with the rotor shaft coaxially to an input shaft of the reduction gear of the sprocket drive, so that the sprocket drive with the liquid-cooled electric motor as the drive motor allows high ground clearance and a large passage between a left and right sprocket drive of the vehicle. Because to supply the electric motor from If only one controller or converter is required for a traction battery, an electric sprocket drive for an electrically, in particular battery-electric, operated tracked or caterpillar vehicle can thus be provided overall, which has compact dimensions and low construction costs, so that with the electric according to the invention Sprocket drive, the requirements for ground clearance and passage between a left and right sprocket drive can be met in an electrically, in particular battery-electrically operated, tracked or caterpillar vehicle.

According to an advantageous embodiment of the invention, the liquid cooling of the electric motor has rotor shaft cooling, the rotor shaft cooling having an axial channel in the rotor shaft, which is designed as a coolant channel for a cooling fluid, in particular oil, of the liquid cooling and is connected to a cooling fluid inlet and a cooling fluid outlet. With such a rotor shaft cooling, the shaft-rotor group of the electric motor, where high temperatures occur, can be specifically cooled. Liquid cooling with a cooling fluid, for example oil, enables a high cooling capacity with little effort.

According to an advantageous embodiment of the invention, the rotor shaft is rotatably coupled at a first end to the input shaft of the reduction gear, with the axial channel extending from an opposite second end of the rotor shaft into the rotor shaft. The axial channel is thus machined into the rotor shaft from the end face at the second end of the rotor shaft opposite the reduction gear, as a result of which the axial channel for cooling the rotor shaft can be produced in a simple and cost-effective manner.

According to an advantageous development of the invention, the rotor shaft is rotatably mounted in the area of the first end by means of a first bearing in a motor housing and in the area of the second end by means of a second bearing in the motor housing, the axial channel extending in the axial direction of the rotor shaft from the End face of the second end of the rotor shaft extends beyond the second bearing, the rotor into the area of the first bearing. With the rotor shaft cooling, the two bearings of the rotor shaft continue to be cooled and reduced temperatures are achieved at both bearings. Because the axial channel of the rotor shaft cooling system extends into the area of the first bearing and thus into the area of the first end of the rotor shaft, where the rotor shaft is rotationally connected to the input shaft of the reduction gear, heat input from the electric motor into a gear oil of the Reduction gear limited or avoided and thus lubricant temperature application limits of the gear oil of the reduction gear are safely maintained.

If, according to an advantageous development of the invention, a shaft sealing ring is arranged in the area of the first bearing and in the area of the second bearing on the rotor shaft, effective cooling of the temperature-critical shaft sealing rings and reduced temperatures on the two shaft sealing rings can also be achieved with the rotor shaft cooling.

According to an advantageous embodiment of the invention, the axial channel is designed as a central blind hole in the rotor shaft, in which a tube is arranged concentrically, with an annular gap being formed between the tube and the blind hole and the tube interior being in flow communication with the annular gap. As a result, the cooling fluid of the cooling fluid circuit can be supplied via the inner space of the tube and removed again via the annular gap surrounding the tube, as a result of which effective cooling of the rotor shaft is achieved.

With regard to a simple connection of the pipe and the annular gap to the cooling fluid circuit, there are advantages if, according to one embodiment of the invention, the pipe is connected to the cooling fluid inlet of the cooling fluid circuit in the area of the second end of the rotor shaft and the pipe in the area of the first end of the rotor shaft is connected by means of at least a recess is connected to the annular gap, wherein the annular gap is connected to the cooling fluid outlet of the cooling fluid circuit.

According to an advantageous embodiment of the invention, the cooling fluid inlet of the cooling fluid circuit has a connection body to which the pipe is attached and which is arranged on a front cover of the motor housing. With such a connection piece, the pipe can be held and connected to the cooling fluid inlet in a simple manner. According to an advantageous development of the invention, the rotor shaft is provided with a braking device at the second end, the braking device being arranged in a brake installation space formed between an end shield in which the second bearing is installed and the front cover of the motor housing. In this way, the sprocket drive can easily be provided with a braking device that brakes the rotor shaft, for example a standstill brake, which is easily accessible via the cover for maintenance work.

If, according to an advantageous development of the invention, the brake installation space is connected to the annular gap and the cooling fluid outlet of the cooling fluid circuit is connected to the brake installation space, the liquid cooling can continue to cool the brake device in a simple manner.

According to an advantageous embodiment of the invention, the cooling fluid outlet of the cooling fluid circuit has a connection bore which is arranged in the cover of the motor housing or in the connection body and is connected to the brake installation space. With such a connection bore, the brake installation space, which is connected to the annular gap, can be connected to the cooling fluid outlet in a simple manner.

According to a preferred embodiment of the invention, the liquid cooling of the electric motor has, alternatively or additionally, a stator cooling of a stator arranged in the motor housing. With such a stator cooling, the stator of the electric motor, where high temperatures occur, can be cooled in a targeted manner. Liquid cooling with a cooling fluid, for example oil, enables a high cooling capacity with little effort.

According to an advantageous embodiment of the invention, the stator and/or the end windings of the stator are arranged in a coolant space of the motor housing that is sealed off from a rotor installation space of the motor housing, the coolant space being connected to a cooling fluid inlet and to a cooling fluid outlet for a cooling fluid, in particular oil, of the liquid cooling is. The coolant space in which the stator and/or the end windings of the stator are arranged can thus be flowed through in a simple manner by a flow of cooling fluid in order to cool the To achieve stator and the end windings of the stator of the electric motor, splashing losses can be avoided by cooling fluid located in the rotor installation space.

If the coolant space extends from the first winding overhang to the second winding overhang and the cooling fluid inlet is arranged in the area of a first winding overhang of the stator and the cooling fluid outlet is arranged in the area of a second winding overhang of the stator, the stator can be arranged over its entire length including the winding overhangs at the axial ends of the stator can be effectively cooled.

According to an advantageous embodiment of the invention, the motor housing is provided with a coolant channel, which extends along the stator, for a cooling fluid, in particular oil, for liquid cooling. A coolant channel for the cooling fluid, which is formed in the motor housing and extends along the stator, enables a further improvement in the cooling of the stator.

If the coolant channel extends from a first winding overhang of the stator to a second winding overhang of the stator, the stator can be effectively cooled over its entire length including the winding overhangs at the axial ends of the stator.

The coolant channel is expediently connected to a cooling fluid inlet arranged on the motor housing and a cooling fluid outlet arranged on the motor housing. As a result, the coolant channel can be connected to the cooling fluid circuit in a simple manner.

According to an advantageous embodiment of the invention, the coolant channel is designed as a spiral groove, which is designed in a sleeve arranged in the radial direction between the stator and the motor housing. With such a sleeve provided with a spiral groove, which is fastened in a suitable manner in the motor housing, for example is pressed in, a coolant channel extending along the stator can be produced in the motor housing in a simple manner.

The invention also relates to a tracked vehicle with at least one sprocket drive according to the invention. According to an advantageous embodiment of the invention, the tracked vehicle has an electrical, in particular battery-electric, drive system in which a traction battery supplies the electric motor of the sprocket drive with electrical energy. The electric sprocket drive according to the invention, which has a compact design due to the liquid cooling of the electric motor, makes it possible, in the case of an electrically, in particular battery-electric, operated chain or

Crawler vehicle to provide an electric sprocket drive with compact dimensions and low construction costs, which results in high ground clearance and a large passage between a left and right sprocket drive of the crawler vehicle. The electric sprocket drive according to the invention is particularly suitable for small tracked or caterpillar vehicles, for example mini excavators, mini dampers, small mobile caterpillar work platforms or small mobile caterpillar drills.

The invention offers a number of advantages:

An electric sprocket drive with compact dimensions is made available by means of the liquid cooling of the electric motor. The liquid cooling of the electric motor also makes it possible, in addition to the electric motor itself, to cool the braking device and the reduction gear of the turbocharger drive.

The liquid cooling of the electric motor means that the mechanical bearings of the rotor shaft are no longer beyond the

Lubricant temperature application limits are loaded, this also applies to the shaft sealing rings on the rotor shaft and the gear oil of the reduction gear. These components (bearings, shaft sealing rings, gear oil of the reduction gear) benefit greatly in terms of their service life, since operation every 10°C below the permitted limit temperature means a doubling of the service life.

The liquid cooling of the electric motor reduces its temperature and thus the electrical losses of the electric motor. Resistive aluminum and copper losses increase by 4° per °C, so reduced temperatures of the electric motor reduce its energy consumption. The liquid cooling of the electric motor makes it possible to operate the electric motor with a higher current density due to the determined heat dissipation and thus to generate a higher torque, which leads to a higher utilization (greater power) of the electric motor.

When using an oil as the cooling fluid, the cooling fluid can be used as an insulator and as a corrosion inhibitor.

With the determined liquid cooling, which is laid in safe hoses to the sprocket drive and away from the sprocket drive, it is ensured that the sprocket drives are effectively cooled and do not overheat even in the deepest terrain, for example mud, water, dirt.

With the liquid cooling of the electric motor, the specification of a time limit for the power to be applied by the electric motor can be increased.

Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiments illustrated in the schematic figures. Here shows

Figure 1 shows a first embodiment of a sprocket drive according to the invention in a longitudinal section and

FIG. 2 shows a second embodiment of a sprocket drive according to the invention in a longitudinal section.

FIGS. 1 and 2 each show an electric sprocket drive 1 according to the invention for a tracked or caterpillar vehicle. The same components are provided with the same reference numbers. The tracked or caterpillar vehicle preferably has an electric drive system, for example a battery-electric drive system.

The sprocket drive 1 according to the invention has a drive motor 2, a reduction gear 3 driven by the drive motor 2 and a hub driven by the reduction gear 3, which are shown in FIG Embodiment is designed as a sprocket 4. The sprocket wheel 4 is used to drive a caterpillar track K of a tracked vehicle or a rubber track K of a caterpillar vehicle.

The sprocket drive 1 has a hub carrier 5 which is fastened to a vehicle frame, not shown, of the tracked or tracked vehicle. A hub 6 is rotatably mounted about an axis of rotation D on the hub carrier 5 by means of bearings 7, which are formed by roller bearings in the illustrated exemplary embodiments. The rotatable hub 6 is provided with the sprocket 4 .

The hub carrier 5 and the hub 6 form a gear installation space 10 in which the reduction gear 3 is arranged. In the exemplary embodiment shown, the reduction gear 3 is designed as a multi-stage planetary gear, in which a sun shaft forms an input shaft 11 and a ring gear on the output side is formed by the hub 6 . The input shaft 11 is arranged coaxially to the axis of rotation D.

In the case of the sprocket drive 1 according to the invention, the drive motor 2 is designed as an electric motor 12 . The electric motor 12 has a motor housing 13 which is attached to the hub carrier 5 . A stator 14 of the electric motor 12 is fastened in the motor housing 13 . In the exemplary embodiments shown, the stator 14 is provided with a winding overhang 14a, 14b at each of the two axial ends. A rotor 15 of the electric motor 12 is also arranged in the motor housing 13 and is fastened to a rotatable rotor shaft 16 .

The rotatable rotor shaft 16 of the electric motor 12 is arranged coaxially to the input shaft 11 of the reduction gear 3 and thus coaxially to the axis of rotation D.

The rotor shaft 16 is coupled in a torque-proof manner to the input shaft 11 of the reduction gear 3 at a first end facing the reduction gear 3 .

The rotor shaft 16 is rotatably mounted in the motor housing 13 in the area of the first end by means of a first bearing 20 in the motor housing 13 and in the area of a second end opposite the first end by means of a second bearing 21 rotatably mounted in the motor housing 13. The bearings 20, 21 are formed in the illustrated embodiments of roller bearings,

In the exemplary embodiments shown, the motor housing 13 has a tubular housing part 23 in which the stator 14 is fastened. A first end shield 24 is fastened to the housing part 23, in which the first bearing 20 is arranged, and a end cover 25 is fastened, which is provided with a second end shield 26, in which the second bearing 21 is arranged. The housing part 23 with the end shield 24 and the cover 25 forms a rotor installation space 27 in which the rotating rotor 15 of the electric motor 12 is arranged.

The rotor shaft 16 is provided at the second end with a braking device 30 which is arranged in a brake installation space 31 formed between the second bearing plate 26 in which the second bearing 21 is installed and the end cover 25 of the motor housing 13 . In the exemplary embodiments shown, the braking device 31 is designed as a disk brake which has a plurality of rotor disks alternately connected in a torque-proof manner to the rotor shaft 16 and stator disks connected in a torque-proof manner to the cover 25 . In the exemplary embodiments shown, the braking device 31 is designed as a spring-loaded brake which is acted upon by a spring device 32 into a braking position. In the illustrated exemplary embodiments, the spring-loaded brake can be hydraulically acted upon into a release position, for which purpose a brake piston 33 is provided, which is arranged so as to be axially displaceable between the bearing plate 26 and the cover 25 and is acted upon in the direction of a release position by a hydraulic brake-release pressure present in a brake-release pressure chamber 34. In the exemplary embodiments shown, the spring device 32 is arranged in the second bearing plate 26 and acts on the brake piston 33 into a braking position. Alternatively, the spring-loaded brake can be designed so that it can be actuated electrically, for example by means of a magnet, into the release position.

In the area of the first end of the rotor shaft 16 , a shaft sealing ring 40 is arranged adjacent to the first bearing 20 between the rotor shaft 16 and the bearing plate 24 , with which the rotor installation space 27 is sealed off from the transmission installation space 10 . In the area of the second end of the rotor shaft 16 , a shaft sealing ring 41 is arranged adjacent to the second bearing 21 between the rotor shaft 16 and the bearing plate 26 , with which the rotor installation space 27 is sealed off from the brake installation space 31 .

In FIGS. 1 and 2, a bearing sensor 45 is also provided on one of the two bearings 20 and 21, respectively. The bearing sensor 45 can be used to detect the rotational speed of the electric motor 12 and/or to control the speed of the vehicle.

In Figures 1 and 2, a protective tube 46 is also attached to the hub carrier 5, within which the motor housing 13 of the electric motor 12 is located.

In order to achieve compact dimensions of the electric motor 12, which allow high ground clearance and a large passage between a left-hand sprocket drive and a right-hand sprocket drive of the tracked or caterpillar vehicle, the electric motor 12 is provided with liquid cooling for its cooling, which includes a cooling fluid circuit.

In FIG. 1 and FIG. 2, the liquid cooling of the electric motor 12 has rotor shaft cooling. The rotor shaft cooling system has an axial channel 50 in the rotor shaft 16 which is designed as a coolant channel for a cooling fluid, in particular oil, of the liquid cooling system and is connected to a cooling fluid inlet 60 and a cooling fluid outlet 61 .

The axial channel 50 extends into the rotor shaft 16 from a second end of the rotor shaft 16 opposite the first end at which the rotor shaft 16 is coupled to the input shaft 11 of the reduction gear 3 .

In Figures 1 and 2, the axial channel 50 extends in the axial direction of the rotor shaft 16 from the end face 51 of the second end of the rotor shaft 16 via the second bearing 21, the rotor 15 to the area of the first bearing 20.

The axial channel 50 is designed as a central blind hole in the rotor shaft 16 which is worked into the rotor shaft 16 from the end face 51 . In the centric A tube 52 is arranged concentrically in a blind hole. An annular gap 53 is formed between the tube 52 and the blind bore. The interior of the tube 52 is in fluid communication with the annular gap 53 .

The tube 52 is connected to the cooling fluid inlet 60 of the cooling fluid circuit in the area of the second end of the rotor shaft 16, opposite the reduction gear 3, and is connected to the annular gap 53 in the area of the first end of the rotor shaft 16 by means of at least one recess, the annular gap 53 being connected to the cooling fluid outlet 61 of the cooling fluid circuit is connected.

In Figure 1, the tube 52 is held in the region of the first end in the rotor shaft 16, with at least one recess designed as a transverse recess 65 being provided in the tube 52, by means of which the tube interior of the tube 52 is in flow communication with the annular gap 53.

In Figure 2, the tube 52 is arranged in the region of the first end in the rotor shaft 16 so that it cantilevers freely, with the recess being designed as an open end face 66 at the inner end of the tube 52, by means of which the tube interior of the tube 52 is fluidly connected to the annular gap 53 stands.

In FIGS. 1 and 2, the cooling fluid inlet 60 of the cooling fluid circuit has a connection body 70 to which the tube 52 is attached and which is arranged on the front cover 25 of the motor housing 13 .

In FIG. 1, the connection body 70 is formed by a pipe spigot 71, which is arranged in an axial bore of the cover 25 and is provided with a connection piece 72 for a cooling fluid feed line. The tube pin 71 extends through the cover 25 and is inserted into the tube interior of the tube 52 .

In FIG. 2, the connection body 70 is formed by a tube pin 71 which is arranged on a cover plate 75 arranged on the cover 25 . The cover plate 75 is provided with an axial bore 76 which is connected to the pipe journal 71 and to which a cooling fluid feed line can be connected. The tube 52 is inserted and held in the tube pin 71 . The tube pin 71 is in the axial channel 50 arranged in such a way that the annular gap 53 remains between the pipe journal 71 and the axial channel 50 .

The brake installation space 31 is connected to the annular gap 53 in FIGS. The cooling fluid outlet 61 of the cooling fluid circuit is connected to the brake installation space 31 in this case.

For this purpose, a pipe pin 80 is provided in FIG. 1, which is arranged in a connection bore 81 of the cover 25, which is connected to the brake installation space 31, and is provided with a connection piece 82 for a cooling fluid discharge line.

For this purpose, in FIG. 2, the connection body 70 designed as a cover plate 75 is provided with a connection bore 83 connected to the brake installation space 31, to which a cooling fluid discharge line can be connected.

To connect the brake release pressure chamber 34 to a brake pressure line carrying a brake release pressure, a pipe spigot 90 is provided in FIG.

In FIG. 2, to connect the brake release pressure chamber 34 to a brake pressure line carrying a brake release pressure, the cover 25 is provided with a connection bore 93 which is connected to the brake release pressure chamber 34 and to which the brake pressure line can be connected.

The rotor shaft cooling of Figures 1 and 2 operates as follows.

Cool cooling fluid is introduced at the first end into the interior of the pipe 52 via the cooling fluid inlet 60 . The cool cooling fluid flows through the tube 52 in the axial direction and flows via the transverse recess 65 of Figure 1 or the open end face 66 of Figure 2 into the annular gap 53. In the annular gap 53, the cooling fluid flows back to the end face 51 of the rotor shaft 16, whereby the Rotor shaft 16, the two bearings 20, 21 and the two shaft seals 40, 41 are cooled. With the Rotor shaft cooling, the electric motor 12 is cooled from the inside out by means of volume flow convection. The pressure medium flows from the end face 51 of the rotor shaft 16 into the brake installation space 31, as a result of which the brake device 30 is cooled and the heated cooling fluid is discharged at the cooling fluid outlet 61. The cooling fluid can be cooled back again at a heat exchanger connected to the cooling fluid outlet 61 and fed to the cooling fluid inlet 60 .

In FIG. 1 and FIG. 2, the liquid cooling of the electric motor 12 also has a stator cooling of the stator 14 arranged on the motor housing 13 .

In Figure 1 and Figure 2, the stator 14 and the two end windings 14a, 14b are arranged in a coolant space 28 of the motor housing 13 which is sealed off from the rotor installation space 27 of the motor housing 13 and which has a cooling fluid inlet 100 and a cooling fluid outlet 101 for the stator cooling a cooling fluid, in particular oil, which is connected to liquid cooling. The coolant space 28 is here formed by partitions 29a, 29b which are formed or arranged on the motor housing 13 on the end windings 14a, 14b and which are in flow communication with one another in a manner not shown in detail. The cooling fluid inlet 100 is arranged in the area of the first winding overhang 14a of the stator 14 on the motor housing 13 and the cooling fluid outlet 101 in the area of the second winding overhang 14a of the stator 14 on the motor housing 13 .

In FIG. 1, for the stator cooling, the motor housing 13 is additionally provided with a coolant channel 110, which extends along the stator 14, for a cooling fluid, in particular oil, for liquid cooling. The coolant channel 110 extends from the first end winding 14a of the stator 14 to the second end winding 14b of the stator 14 and is connected to the cooling fluid inlet 100 arranged on the motor housing 13 and to the cooling fluid outlet 101 arranged on the motor housing 13 .

The coolant channel 110 is preferably designed as a spiral groove which is formed in a sleeve 115 arranged in the radial direction between the stator 14 and the motor housing 13 . The stator 14 is arranged on the inner wall of the sleeve 115 . In the outer wall of the sleeve 115, the spiral groove is incorporated. The sleeve 115 is preferably pressed into the tubular housing part 23 of the motor housing 13 so that the coolant channel 110 is formed between the outer wall of the sleeve 115 and the inner wall of the housing part 23 .

The stator cooling of Figures 1 and 2 works as follows.

In FIGS. 1 and 2, cool cooling fluid is introduced via the cooling fluid inlet 100 into the coolant space 28 in the region of the end winding 14a. The cool cooling fluid flows through the coolant space 28 in the axial direction, as a result of which the stator 14 and its end windings 14a, 14b are cooled. The heated cooling fluid enters the coolant space 28 in the area of the end winding 14b and is drained off at the cooling fluid outlet 101 . The cooling fluid can be cooled back again at a heat exchanger connected to the cooling fluid outlet 101 and fed to the cooling fluid inlet 100 .

In FIG. 1, additional cooling fluid can be introduced via the cooling fluid inlet 100 into the coolant channel 110 in the area of the first end winding 14a, which flows through the coolant channel 110, whereby the stator 14 and its end windings 14a, 14b are cooled. The heated cooling fluid is discharged at the cooling fluid outlet 101 in the area of the second end winding 14b. The cooling fluid can be cooled back again at a heat exchanger connected to the cooling fluid outlet 101 and fed to the cooling fluid inlet 100 .

The sprocket drive 1 according to the invention provides an electric sprocket drive for a tracked vehicle with an integrated electric motor 12, a multi-stage reduction gear 3 and a braking device 30 designed as a standstill brake, as well as liquid cooling, which has compact dimensions and high ground clearance and a high passage between a left and a allows right door drive 1 of the vehicle. The liquid cooling makes it possible to cool not only the electric motor 12, the reduction gear 3 and the braking device 30 but also the bearings 20, 21 and the shaft sealing rings 40, 41 of the rotor shaft 16.

Claims

patent claims

1. Sprocket drive (1) comprising a drive motor (2), a reduction gear (3) driven by the drive motor (2) and a hub (6) driven by the reduction gear (3), in particular a sprocket wheel (4), characterized in that the drive motor (2) is designed as an electric motor (12), with a rotor shaft (16) of the electric motor (12) connected to a rotor (15) of the electric motor (12) being arranged coaxially with an input shaft (11) of the reduction gear (3). and the electric motor (12) is provided with liquid cooling for cooling, which comprises a cooling fluid circuit.

2. Turret drive according to Claim 1, characterized in that the liquid cooling of the electric motor (12) has a rotor shaft cooling system, the rotor shaft cooling system having an axial channel (50) in the rotor shaft (16) which is used as a coolant channel for a cooling fluid, in particular oil, of the liquid cooling system is formed and is connected to a cooling fluid inlet (60) and a cooling fluid outlet (61).

3. Turas drive according to claim 2, characterized in that the rotor shaft (16) is coupled at a first end to the input shaft (11) of the reduction gear (3) in a rotationally fixed manner, the axial channel (50) extending from an opposite second end of the rotor shaft ( 16) extends out into the rotor shaft (16).

4. Turas drive according to claim 2 or 3, characterized in that the rotor shaft (16) is rotatably mounted in the region of the first end by means of a first bearing (20) in a motor housing (13) and in the region of the second end by means of a second bearing ( 21) is rotatably mounted in the motor housing (13), the axial passage (50) extending in the axial direction of the rotor shaft (16) from the end face (51) of the second end of the rotor shaft (16) via the second bearing (21), extends the rotor (15) into the area of the first bearing (20).

5. Turas drive according to claim 4, characterized in that in the region of the first bearing (20) and in the region of the second bearing (21) on the rotor shaft (16) in each case a shaft sealing ring (40, 41) is arranged.

6. Turas drive according to one of claims 2 to 5, characterized in that the axial channel (50) is designed as a central blind bore in the rotor shaft (16), in which a tube (52) is arranged concentrically, with between the tube (52) and an annular gap (53) is formed in the blind bore and the interior of the tube is in fluid communication with the annular gap (53).

7. Turas drive according to claim 6, characterized in that the tube (52) in the region of the second end of the rotor shaft (16) is connected to the cooling fluid inlet (60) of the cooling fluid circuit and the tube (52) in the region of the first end of the rotor shaft ( 16) is connected to the annular gap (53) by means of at least one recess, the annular gap (53) being connected to the cooling fluid outlet (61) of the cooling fluid circuit.

8. Turret drive according to claim 7, characterized in that the cooling fluid inlet (60) of the cooling fluid circuit has a connection body (70) to which the tube (52) is attached and which is arranged on a front cover (25) of the motor housing (13). .

9. Turas drive according to one of claims 4 to 8, characterized in that the rotor shaft (16) is provided at the second end with a braking device (30), the braking device (30) in a between a bearing plate (26) in which the second bearing (21) is installed, and the front cover (25) of the motor housing (13) is arranged in the brake installation space (31).

10. Turas drive according to claim 9, characterized in that the brake installation space (31) is connected to the annular gap (53) and the cooling fluid outlet (61) of the cooling fluid circuit is connected to the brake installation space (31).

11. Turret drive according to Claim 10, characterized in that the cooling fluid outlet (61) of the cooling fluid circuit has a connection bore (81; 83) which is arranged in the cover (25) of the motor housing (13) or in the connecting body (70) and which is connected to the brake installation space (31) is connected.

12. Turas drive according to one of claims 1 to 11, characterized in that the liquid cooling of the electric motor (12) has a stator cooling of a motor housing (13) arranged stator (14).

13. Turret drive according to claim 12, characterized in that the stator (14) and/or end windings (14a; 14b) of the stator (14) are in a coolant space (28) of the motor housing that is sealed off from the rotor installation space (27) of the motor housing (13). (13) is arranged, wherein the coolant space (28) with a cooling fluid inlet (100) and with a cooling fluid outlet (101) for a cooling fluid, in particular oil, the liquid cooling is connected.

14. Turret drive according to Claim 13, characterized in that the coolant chamber (28) extends from the first winding overhang (14a) to the second winding overhang (14b) of the stator (14) and the cooling fluid inlet (100) in the region of a first winding overhang (14a ) of the stator (14) and the cooling fluid outlet (101) is arranged in the region of a second end winding (14b) of the stator (14).

15. Turas drive according to one of claims 12 to 14, characterized in that the motor housing (13) is provided with a along the stator (14) extending coolant channel (110) for a cooling fluid, in particular oil, the liquid cooling.

16. Turas drive according to claim 15, characterized in that the coolant channel (110) extends from a first end winding (14a) of the stator (14) to a second end winding (14b) of the stator (14).

17. Turas drive according to claim 15 or 16, characterized in that the coolant channel (110) is connected to the cooling fluid inlet (100) arranged on the motor housing (13) and the cooling fluid outlet (101) arranged on the motor housing (13).

18. Turas drive according to one of claims 15 to 17, characterized in that the coolant channel (110) is designed as a spiral groove which is arranged in a radial direction between the stator (14) and the motor housing (13) sleeve (115) is formed .

19 tracked vehicle with at least one sprocket drive (1) according to any one of the preceding claims.

20. Tracked vehicle according to claim 19, characterized in that the

Tracked vehicle has an electrical, in particular battery-electric, drive system in which a traction battery supplies the electric motor of the sprocket drive (1) with electrical energy.