Auxiliary unit for railway wheel sets

Abstract

Auxiliary unit for railway wheel sets, with hollow shafts of lightweight construction, which is designed as an electric machine (E-machine) with a reduction gear connected to it for starting and transporting a railway carriage, wherein the E-machine and the reduction gear are mounted on a common rotor shaft, and which comprises a connection unit which is firmly connected to the front of the auxiliary unit towards the bearing cover.

Description

[0001] The invention relates to an auxiliary unit for railway wheel sets, with hollow shafts of lightweight construction.

[0002] The auxiliary unit according to the invention is used in particular on railway freight cars as an auxiliary drive for shunting movements independent of a locomotive, as well as an independent drive unit for operating electrical machines, pumps, or similar auxiliary devices in connection with the operation of railway cars, provided these are equipped with railway wheelsets that have railway axles in the form of hollow shafts. Such lightweight hollow shafts are currently in the development stage. With inner diameters in the order of approximately 250 mm, such hollow shafts, as components of the present invention, offer sufficient space for the auxiliary unit according to the invention.

[0003] Electric drive units for motor vehicles are known that are also suitable for rail vehicles (DE 10338659 A1; DE 19732637 A1; DE 10322022 A1). These units are arranged coaxially around a drive shaft in the hub area of the wheels. In an electric hollow-shaft drive motor for rail vehicles (DE 10322022 A1), the drive motor components are located in an open housing that is firmly connected to the bogie of the vehicle structure.

[0004] In addition to the rotor and stator of the drive motor, an elastic coupling is arranged between the rotor and the output within a through opening in the housing in such a way that it allows displacements between the output and the drive motor.

[0005] The present invention is based on the object of creating an auxiliary unit as described above, which is particularly compact in design so that it is capable, on the one hand, of moving a loaded freight wagon in shunting operation and, on the other hand, of being used as any auxiliary unit for use in railway operation in the case of locomotive-driven wagon propulsion, ie with reversed power flow, starting from the hollow shaft, such as, for example, an electric motor, generator, hydraulic pump or similar work equipment.

[0006] To solve the above problem both for the self-propelled function and for the operation of special auxiliary units, reference is made to the combination of features characterized in patent claim 1.

[0007] The combination of features according to the invention comprises a plurality of auxiliary units, namely in an essential embodiment a drive unit for starting and transporting a railway carriage (cf. subclaim 2), wherein the auxiliary unit is designed as an electric machine (E-machine) with a reduction gear connected thereto ( Fig. 1) which have a common rotor shaft, and wherein the reduction gear transmits the rotation of the rotor shaft to the hollow shaft in accordance with the reduction ratio (cf. subclaim 3).

[0008] In an embodiment according to the invention, with particular consideration of the narrow installation space present inside the hollow shaft, the reduction gear is designed as a planetary gear, the ring gear of which is firmly connected to the housing of the electric motor and the gear parts of which are in driving connection with an internal toothing of the hollow shaft (cf. subclaim 4).

[0009] In a particularly preferred design of the reduction gear, it is provided that it is designed as a two-stage planetary gear (cf. subclaim 5).

[0010] A cycloidal gear can also be considered as a suitable reduction gear, whereby particularly high reduction ratios can be achieved.

[0011] Numerous further possible uses of the auxiliary unit according to the invention, insofar as it is preferably used in connection with railway operations, are possible in further embodiments according to the present invention.

[0012] In this context, an embodiment as an electric machine for charging a battery ( Fig. 2) or as a generator for electricity production ( Fig. 3); these embodiments are each designed without a gearbox.

[0013] When an electric motor is used as a battery charger or as a power supply for smaller power outputs, an external rotor electric motor is preferred. For generator operation, an internal rotor electric motor is preferred, with such variants being particularly advantageous when implementing the so-called industrial common parts concept.

[0014] Within the framework of the concept of an auxiliary power unit for railway carriages proposed according to the invention, the focus is on designing an electric motor with or without a gearbox suitable for internal installation in lightweight hollow shafts of railway wheel sets. A key feature of the invention is the provision of a central connection unit which is connected to the front of the electric motor or another working device and which is centrally arranged within a bearing flange of the railway wheel and fixedly mounted there. The auxiliary power unit according to the invention therefore represents an overall concept by means of the connection unit, wherein the connection unit not only assumes bearing functions but also serves as a support element for external cable connections. This concerns cable connections, for example in the form of bores for accommodating power lines orCable connections or channels for guiding cooling media, for example for cooling electric motors using compressed air.

[0015] In an embodiment according to the invention with a hydraulic working device in the form of a gear pump ( Fig. 4) A pump housing is provided within the hollow shaft, which is fixedly mounted therein, whereby the pump elements are driven by the rotation of the hollow shaft.

[0016] Due to the high idle speed of locomotive drive, the electric motor and / or transmission rotate continuously. The resulting drag torque and associated energy consumption can be avoided by installing clutches, which are advantageously isolated between the electric motor and the reduction gear or between the hollow shaft and the auxiliary unit.

[0017] In addition to providing traction power, the electric motor can also be used for wear-free braking. The released energy can, for example, be used to charge a battery and then later reused for propulsion work. It can also be fed into the railway network if the necessary technical requirements are met. Alternatively, the released energy can be converted into heat via a braking resistor. The electric motor is used in 4-quadrant operation, meaning it can be used in both directions of rotation, both as a motor and as a generator.

[0018] In the following, exemplary embodiments of the invention are explained with reference to the drawings. They show: Fig. 1 an electric motor auxiliary unit with electric motor and planetary gear in a longitudinal section through the rotation axis, Fig. 2 an electric motor auxiliary unit with a cantilevered stator in a longitudinal section through the stator axis, Fig. 3 an auxiliary electric motor unit as a generator and Fig. 4 an auxiliary unit as a hydraulic pump.

[0019] Fig. Figure 1 shows a longitudinal section through a lightweight railway axle for railway wheelsets, which have hollow shafts constructed in a lightweight manner. The wheel-side end 2 of such a hollow shaft 1 is shown, which has a cylindrical cross-section and is welded to a welding flange 3. The associated wheel disc 5, which forms a railway wheel of a railway wheelset, is fastened between the welding flange 3 and a bearing flange 4, which forms the shaft end. All components of the respective auxiliary unit are accommodated within the limited cavity of the hollow shaft 1, with an inner diameter of the tube 2 of approximately 200-250 mm, and the adjoining flange parts of the welding flange 3 and the bearing flange 4. The installation space is closed at its outer end by a bearing cover 7, which is connected to the front end of an outer housing 8 of the Fig. 1 is screwed all the way around by means of screws 9. A rolling bearing 10 is arranged within the bearing cover 8, in which the end of the bearing flange 4 is rotatably received.

[0020] The Fig. The auxiliary unit shown in Figure 1 comprises an electric motor 11 as a motor with a motor housing 12, rotor 13, and stator 14, with the rotor 13 being non-rotatably mounted on a rotor shaft 15. The electric motor 11 serves as a drive for a reduction gear for starting and transporting a railway carriage, the wheelset of which is drivingly connected to the hollow shaft 1.

[0021] The reduction gear is designed as a planetary gear 16, the ring gear 17 of which is fixedly connected to the motor housing 12 and the gear parts of which are in drive connection with an internal toothing 18 of the hollow shaft 1.

[0022] Fig. 1 shows a two-stage planetary gear unit whose gear components allow dimensioning of the reduction gear unit with smaller radial dimensions compared to a single-stage planetary gear unit.

[0023] The illustrated two-stage planetary gear comprises, in addition to the ring gear 17, a planet carrier 19 of planetary stage 1 with planet gears 19a and a planet carrier 20 of planetary stage 2 with planet gears 20a. The planet gears are each mounted on the respective planet carrier 19 or 20 via roller or ball bearings. The planet gears 19a or 20a each mesh with the internal toothing of the ring gear 17. The ring gear 17 is cup-shaped and is centrally screwed to the motor housing 12 of the electric motor 11.

[0024] In stage 1 of the planetary gear 16, the planetary gears 19a are driven via the toothing 21 of the sun gear of planetary stage 1 and mesh with the internal toothing of the ring gear 17.

[0025] In stage 2 of the planetary gear 16, the planet gears 20a mesh, on the one hand, with the internal toothing of the ring gear 17 and, on the other hand, engage with an external toothing 19b of the planet carrier 19 of stage 1. This, in turn, drives the planet carrier 20 of stage 2, whose external toothing 18 meshes with an internal toothing of the welding flange 3 of the hollow shaft 1, thus enabling the desired reduction ratio of 1:20, corresponding to a 20-fold increase in torque.

[0026] The reduction gear is permanently oil-lubricated and sealed to the outside with a cover 22. Additionally, an axial oil seal 23 is provided between the planetary carrier 20 of planetary stage 2 and the ring gear 17.

[0027] For the installation of any auxiliary power unit in the limited cavity of a hollow shaft 1 of railway wheelsets, an essential technical requirement is to provide the auxiliary power unit with external cable connections via a connected connection unit 25 to support the mounting of the auxiliary power unit and its supply. These include, for example, cable ducts for the electrical supply, for the electronic control system, for cooling media for operating electric motors, for hydraulic lines, or the like.

[0028] According to Fig. 1, the connecting unit 25 is fixedly arranged at the front within the bearing flange 4. At its outer end, it is supported by a rolling bearing 26 relative to the bearing flange 4, and its inner end is firmly screwed to the motor housing 12 by means of circumferentially arranged screws 27. At its front end, the connecting unit 25 is connected to the bearing cover 7 by means of a spline 28, which serves as a torque support.

[0029] A compressed air duct 29 for cooling the electric motor 11 and a central supply duct 30 for accommodating cable connections, which serve the power supply and machine control and have corresponding branches to the respective access points, are connected to the outside via corresponding feeds through the bearing cover 7 by means of supply connections (not shown). The rolling bearing 26 is sealed to the outside by a pressure-resistant shaft seal 31 relative to the bearing cover 7. This is necessary for safety reasons, since pressure monitoring within the hollow shaft 1 must be ensured to maintain the overpressure prevailing in the hollow shaft 1, appropriate to the operating conditions.

[0030] The holes extending from the compressed air line 29 through the bearing cover 7 and the connection unit 25 terminate on the electric motor side in a circumferential distributor housing 32, whose cavity expels the compressed air through the gap between the stator 14 and rotor 13 of the electric motor via axial nozzles (not shown). The heated cooling air finally returns via the cavity 33 and further channels in the housing of the electric motor 11 and exits through the central hole 30, where it is fed back to an external compressor unit. In this way, the central hole 30 is used both as a cable duct and for the return of the exhaust air.

[0031] The selected constructive solution to the problem according to the invention by positioning an auxiliary unit in the connection area of a railway hollow shaft 1 within the wheel disc 5 screwed between the welding flange 3 and the bearing flange 4 represents a novel multifunctional design of the hollow shaft end section of railway wheel sets with lightweight shafts that supports the wheel disc 5.

[0032] The following are variants of the Fig. 1 described auxiliary unit in a brief but not exhaustive overview.

[0033] Fig. Figure 2 shows an electric motor auxiliary unit with a cantilevered stator 40, comprising a winding 41 with a laminated core 42, which is fixedly mounted on a central stator axis 43. The rotor of this auxiliary unit, shown in longitudinal section, consists of permanent magnets 44, which are centrally mounted within a carrier ring 45, which is connected in a rotationally fixed manner to the bearing bore of the wheel disc 5 between the welding flange 3 and the bearing flange 4. Furthermore, Fig. 2 with the auxiliary unit according to Fig. 1 similar components are designated by the same reference numerals, which also applies to the following Fig. 3 and Fig. 4 applies. In this respect, there is no need to repeat what has already been said in connection with Fig. 1 description parts.

[0034] Deviating from the Fig. The external rotor of the electric motor 40 described in Figure 2, which is a synchronous machine with magnetic induction and in practical use serves as a simple battery charger or small power supply, is suitable for use in larger electric motors as a generator, preferably in the form of an internal rotor. With particular attention to the common parts concept in industrial production, the following Fig. 3 describes an electric machine which is designed as an internal rotor, thus a Fig. 1 largely similarly designed electric motor as an internal rotor. The generator according to Fig. 3 is driven via a toothed hub profile 51 on the inside of the welding flange 3 of the lightweight shaft 1, wherein a drive gear 52 meshing with the toothed hub profile 51 is mounted in a rotationally fixed manner on the inner end of the generator shaft 53.

[0035] Fig. 4 shows an auxiliary unit comprising a working device 60, installed in a Fig. 1 to 3 identical lightweight shaft 1. The working device 60 is a hydraulic pump, for example in the form of a gear pump or an axial piston pump, whose housing is fixedly mounted within the hollow shaft 1 and whose axle stub 61 engages with an external toothing into the internal toothing of a driving bushing 62. A bearing ring 63, which is connected in a rotationally fixed manner to the pump housing, is mounted on the driving bushing 62 via a roller bearing 64. The driving bushing 62 is seated in a rotationally fixed manner in the center of a drive sleeve 65, which in turn is connected in a rotationally fixed manner with its outer circumference to the inner circumference of the welding flange 3.

[0036] The connecting part 25, which is connected to the hydraulic pump at the front, has two bores for the oil circuit with a supply channel 66 and a discharge channel 67, with both channels connected to the outside via the bearing cover 7. In this way, the oil circuit is ensured for the operation of any components of the railway wagon while it is driven by the locomotive.

Claims

[1] Auxiliary unit for railway wheel sets, with lightweight hollow shafts, which is characterized by the following features: a) it is installed in the cavity of a hollow shaft (1); b) it extends inside the hollow shaft (1) to within a bearing flange (4), of a railway wheel (5) connected to the hollow shaft in a rotationally fixed manner to the associated bearing cover (7) of a wheelset bearing (10); c) it comprises a connection unit (25) which is firmly connected to the bearing cover (7) at the front; d) the connecting unit (25) is fixedly mounted within the bearing flange (4) at least at its end adjacent to the bearing cover (7); e) the connection unit (25) is provided with cable connections leading outwards through the bearing cover (7). [2] Auxiliary unit according to claim 1, characterized bythat it is designed as an electric machine (E-machine 11) with a reduction gear connected thereto for starting and transporting a railway carriage and that the E-machine (11) and the reduction gear are mounted on a common rotor shaft (15). [3] Auxiliary unit according to claim 2, characterized by that the reduction gear is connected to the housing (12) of the electric machine (11) in such a way that it transmits the rotation of the rotor shaft (15) to the hollow shaft (1) in accordance with the reduction ratio. [4] Auxiliary unit according to claim 3, characterized by that the reduction gear is designed as a planetary gear (16), the ring gear (17) of which is firmly connected to the housing (12) of the electric motor (11) and the gear parts of which are in driving connection with an internal toothing (18) of the hollow shaft (1). [5] Auxiliary unit according to claim 4, characterized bythat the transmission parts are formed by a 2-stage planetary gear. [6] Auxiliary unit according to claim 1, characterized by that when the hollow shaft (1) is driven by a locomotive, a clutch between the electric motor and the reduction gear can be switched as a separation. [7] Auxiliary unit according to claim 1, characterized by that when the hollow shaft (1) is driven by a locomotive, a coupling between the hollow shaft and the auxiliary unit can be switched as a separator. [8] Auxiliary unit according to claim 1, characterized by that it comprises a working device (60) which is fixedly mounted within the hollow shaft (1) and which is connected to the hollow shaft (1) in a rotating manner.

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