Gearbox for a drive device for a vehicle, a gear for a gearbox and vehicle with a gearbox

Description

Technical field

[0001] The present invention relates to a transmission for a drive device for a vehicle, in particular for a rail vehicle or bus. The invention further relates to a gear for such a transmission, a drive device with such a transmission, and a vehicle with such a drive device. Prior art

[0002] It is known that vehicles have transmissions to convert speeds and torques as needed. For example, such a vehicle can be a rail vehicle, which has a drive unit with an electric motor and a transmission.

[0003] In some cases, an electric current may flow through the gearbox via an output shaft of the electric motor, which can lead to material damage at transition points.

[0004] Current flow can be caused, for example, by the various capacitances that arise within the drive system. The rotor of the electric motor has a capacitance to the stator housing via the air gap. The motor windings are insulated and therefore exhibit capacitance to both the rotor and the stator housing. The lubricating film in the bearing between the inner ring and rolling elements, as well as between the outer ring and rolling elements, acts as an insulator. Thus, two capacitances in series also arise within the bearing. It must be noted that the bearing capacitances are variable. Depending on the operating conditions, the lubricating film in the bearing is thinner or thicker. When stationary, there may also be direct contact between the rolling elements and the bearing ring, thus eliminating the bearing's capacitance. The lubricating film thickness, and therefore the capacitance, depends, among other things, on mechanical load, temperature, and the type of lubricant.Due to the capacitance of the winding to the stator housing, losses occur in the windings in the form of additional earth currents in the stator, which excite circular, high-frequency magnetic fluxes around the rotor. These fluxes induce voltages in the shaft, which, upon overcoming the lubricating film, lead to circular currents in the motor. The voltages are similar to the classic shaft voltages, but they are significantly higher and higher frequency. The current amplitudes range between 0.5 and 20 A. The damage caused by current flow in rolling bearings has different appearances depending on the cause, e.g., matte gray wear marks, aged lubricant, corrugation, and white etching cracks. Furthermore, these currents can not only circulate but also leak via the rest of the drive system, for example, into a rail.

[0005] Known countermeasures include bearings with internal insulation layers, insulating couplings, suitable grounding, inverters, du / dt filters (motor throttles), sine filters and / or suitable lubricants. Disadvantages of the state of the art

[0006] Such gearboxes for drive devices with the outlined solutions are usually only conditionally optimal with regard to the requirements placed upon them. In particular, the outlined solutions cannot completely eliminate the disadvantages of current flow or the current flow itself. Problem statement

[0007] One object of the present invention is therefore to provide a transmission for a drive device of a vehicle which has a simple and robust design and at the same time achieves an improvement with regard to the presence of unwanted current flows. Inventive solution

[0008] The above problem is solved by a transmission for a drive device for a vehicle according to claim 1, by a gear for such a transmission according to claim 13, by a drive device with such a transmission according to claim 14 and by a vehicle with such a drive device according to claim 15.

[0009] A gearbox for a drive device for a vehicle, in particular for a rail vehicle, is proposed, wherein the gearbox comprises the following: a housing with a first shaft rotatably mounted therein and with a second shaft rotatably mounted in the housing. The first shaft can, for example, be rotationally connected to an electric machine, whereby electric currents generated by the electric machine could flow into the first shaft of the gearbox.

[0010] If the electric machine is operated as an electric motor, the first shaft – in relation to the gearbox – could be called the drive shaft or input shaft. Specifically, the gearbox's drive shaft is connected to an output shaft of the motor.

[0011] A first gear, rotatably connected to the first shaft, interacts with a second gear on the second shaft to create a gear ratio. The second shaft can be referred to as the output shaft, explicitly including the possibility of further transmission shafts and gear stages.

[0012] If the electric machine were operated as a generator, the first shaft, which is rigidly connected to the generator, can be called the output shaft or the drive shaft. That is, the power flows via the output shaft of the gearbox into the input shaft of the generator.

[0013] The first gear and the second gear each have meshing tooth rings.

[0014] To prevent unwanted current flows, the first and / or second shaft is / are insulated from the housing and rotatably mounted, for example by providing insulating roller and / or ball bearings, or by providing insulating means between the shaft and the bearing, and / or between the bearing shell and the bearing receptacle in the housing.

[0015] Furthermore, electrical contact between the gear rings can be effectively prevented by electrically isolating the first gear ring from the first shaft and / or the second gear ring from the second shaft. This prevents electrical current flow through rotating parts or the gearbox housing, resulting in fewer faults and associated material damage.

[0016] According to one embodiment, insulating means are provided to supply electrical insulation between the first shaft and the first gear ring and / or between the second shaft and the second gear ring. In this way, while an electrical potential emanating from an electrical machine connected to the first shaft is permitted to encompass the first shaft and possibly part of the first gear, it effectively prevents current flow between relatively moving / rotating components and parts.

[0017] According to a further embodiment, the insulating means described above can be provided in the area of ​​a shaft-hub connection between the gear and the shaft. For example, such insulation could be designed as an insulating coating and / or as an insulating bushing.

[0018] According to an alternative or additional embodiment, the first shaft is designed as an input shaft or drive shaft in such a way that it enables a rotational energy input into the gearbox.

[0019] Regarding one design, current flow from the first shaft into the housing – or vice versa – is prevented by the ball bearings or roller bearings used for rotational support, which insulate the first shaft from the housing. This also applies, optionally, to the use of additional shafts and bearings.

[0020] According to the invention, it is disclosed that the first gear and / or the second gear is / are designed in two parts. In one embodiment, a radially inner inner section is rotatably connected to or joined with a radially outer outer section.

[0021] According to the invention, the insulating means are provided between the inner section and the outer section, in particular in an effectively insulating manner.

[0022] The inner section and the outer section are connected to each other in a rotationally fixed manner by means of a connecting device and connecting means, so that a transmission of a rotational movement, in particular a transmission of circumferential forces, from the first shaft to the gear ring via the inner section and the outer section (or back) can be realized.

[0023] This approach enables, for the first time, a simple and reliable design for isolating a gearbox, and such a design can also be retrofitted into an existing gearbox. A particular advantage is that an insulating coupling can be eliminated. Furthermore, the described solution is superior to the previously mentioned known solutions because the transmission of circumferential forces can be optimized for force flow, for example, by reducing surface pressures.

[0024] According to a further embodiment, the inner section can be integral, in particular integrally, with the respective shaft, i.e., for example, with the first / second shaft, the input / output shaft, and / or the driven / output shaft. This saves on component parts.

[0025] According to one embodiment, the inner section has a larger outer diameter than a shaft section, in particular a bearing section, of the respective shaft.

[0026] It is further proposed that the gear, which is designed with an inner section and an outer section and with the insulating means provided between them, be further equipped with a connecting device with connecting means, so that power transmission between the inner section and the outer section is ensured.

[0027] According to an advantageous embodiment, the gear rim of the gear, which is formed in at least two parts with an inner section and an outer section, has a larger number of teeth than the gear rim of the other gear. In particular, the gear, which is formed in at least two parts, is designed as a larger gear relative to the gear meshing with it.

[0028] In this context, it should be noted that the term "large gear" is not primarily intended to describe the absolute size, but rather the relative size. Furthermore, in the context of the invention described here, the second gear corresponds to the large gear, so the terms "large gear" and "second gear" can be used synonymously.

[0029] The first gear described in the context of this invention is smaller than the second gear and therefore has fewer teeth. In particular, the first gear can thus be referred to as a pinion, although no absolute geometric dimensions are specified here. When the term "pinion" and / or "large gear" is used below, it refers to a gear stage of the transmission, whereby the pinion and / or the large gear are not necessarily rotationally fixed to a drive and / or output shaft.

[0030] According to one embodiment, the first gear and the second gear, in particular the pinion and the large gear, are provided in the transmission such that either the first gear / pinion or the second gear / large gear is connected to a drive shaft or to an output shaft.

[0031] According to a further aspect, the inner section of the two-part gear, in particular the larger gear, especially the second gear, has an inner flange with an inner flange surface. The outer section is equipped with an outer flange and an outer flange surface, the outer flange being rotationally fixed, in particular integrally, to the gear rim, in particular the second gear rim. Preferably, the flange surfaces extend at least partially in a radial direction of the gear; in particular, the flange surfaces are aligned parallel to a plane of rotation of the gear, i.e., exclusively radially. Accordingly, the inner and outer flanges overlap in the region of the flange surfaces in an axial direction of the gear.

[0032] The insulating means comprise at least one insulating flange disc ring, which can be arranged, and in particular is arranged, between the flange surfaces. The flange disc ring can, for example, be provided locally in the area of ​​fasteners, or extend in a ring shape around the circumference of the flange surfaces.

[0033] According to one embodiment, the insulating means have at least one insulating sleeve and / or an axial insulating element for electrically insulating a connecting means from the inner section or from the outer section.

[0034] In particular, the insulating sleeve is constructed in such a way that it at least partially, preferably completely, encloses a cylindrically shaped connecting element, in particular a screw, so that electrical contact between the connecting element and a bore of the inner section or the outer section in the radial direction of the connecting element is prevented.

[0035] The axial insulating element can, for example, be designed as an insulating washer, so that a head, in particular a screw head, of the fastener is electrically insulated from a bearing surface of the inner section or the outer section in the axial direction of the fastener.

[0036] In a further embodiment, the insulating elements are made at least partially of plastic, in particular polyetheretherketone (PEEK), Vetronit (also known as EP GC 202, HGW 2372.1, EP-4, FR4), aluminum oxide (Al₂O₃), and / or oxide fiber-reinforced oxide ceramic. Sleeves, the axial insulating element (insulating washers), and the insulating flange washer ring can be made of the same type of insulating material, but this is not mandatory.

[0037] According to one embodiment, the materials of the flange disc ring and inner flange and / or outer flange are selected such that the corresponding tribological system has a coefficient of friction of at least µ=0.2, preferably at least µ=0.3, preferably at least µ=0.4.

[0038] In the context of the present invention, a gear for a transmission according to one or more of the previously discussed embodiments is disclosed. The gear is, for example, designed as a large gear. In particular, the gear, in the sense of the present nomenclature, is designed as a second gear and meshes with the first gear. The gear further comprises a toothed rim suitable for meshing with the toothed rim of the first gear, an outer section connected to the toothed rim with an outer flange, an inner section rotatably connected to the outer section in a radial direction, a connecting device designed for connecting the outer section to the inner section, and insulating means, wherein these means are designed and arranged between the inner section and the outer section such that the inner section and the outer section are electrically insulated from each other.Furthermore, it is explicitly disclosed that the previously described design details relating to the gearbox are also considered disclosed with regard to the gear.

[0039] Such a gear makes it possible for the first time to create electrical insulation between shaft-gear and / or housing, and existing gearboxes can also be retrofitted with such an insulating gear.

[0040] In this context, a method for retrofitting gearboxes is disclosed, comprising the steps of: removing an existing gear of a gearbox; providing insulating measures on shaft bearings in a housing of the gearbox, in particular replacing existing rolling or ball bearings with insulating rolling or ball bearings or providing insulating bearing shells accordingly; installing a gear according to one of the embodiments described above.

[0041] According to a further aspect, it is disclosed to provide a drive device for a vehicle, in particular for a rail vehicle, wherein the drive device has at least one transmission according to one of the aforementioned embodiments.

[0042] Furthermore, the drive device includes a drive motor that is rotationally fixed and not electrically insulated from a drive shaft (first shaft) of the gearbox. The drive device is also equipped with an output shaft that is rotaryally connected to the drive shaft via the gearbox, with a gear reduction.

[0043] According to one embodiment, the drive device is integrally designed, i.e., the mounting and partly even the housing of the motor, the gearbox and the bearing of the output shaft are arranged in a common component, wherein the common component can be a combination housing for gearbox, bearing of the drive shaft and support of the motor.

[0044] Furthermore, a rail vehicle comprising a car body and a drive device according to one of the preceding embodiments is disclosed. The drive device may be formed together with the bogie.

[0045] The embodiments described above can be combined with each other in any meaningful way, for example the first gear (pinion) can also be divided into two parts with an inner section and an outer section. Brief description of the characters

[0046] The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to each other and not necessarily to scale.

[0047] Identical reference symbols denote identical or similar parts. Fig. 1shows a rail vehicle with a drive device, Fig. 2 a schematic representation of a gearbox of the drive device of the rail vehicle according to Fig. 1 , Fig. 3 a perspective view of a gear of the transmission according to Fig. 2 , Fig. 4 a partial section through the gear according to Fig. 3 , Fig. 5 a detailed section of a connecting device of the gear according to Fig. 3 and Fig. 4 , and Fig. 6 an axial view of a flange disc ring of the gear according to Fig. 3, Fig. 4 and Fig. 5 . Examples of implementation

[0048] To clarify the overall understanding, the following is used: Fig. 1A rail vehicle 100 is shown. This rail vehicle 100 comprises a car body 102 which is mounted on rails by means of bogies 101 so that it can roll. A drive device 103 for driving the rail vehicle 100 is integrally installed in at least the middle bogie 101, so that the drive device 103 together with the bogie 101 is designed to pivot relative to the car body 102.

[0049] Fig. 2 Figure 1 shows a schematic section through a gearbox 1 of the drive device 103. The illustration is limited to a single gear stage with a first gear 13, in particular designed as a pinion, and with a second gear 23, in particular designed as a two-part large gear. The first gear 13 is non-rotatably connected to a first shaft 10, and the second gear 23 is non-rotatably connected to a second shaft 20 for transmitting circumferential forces.

[0050] Such a shaft-hub connection can be achieved, for example, through the following methods. Friction-fit connections: The force transmission between the shaft and hub occurs through frictional resistance, achieved through press fits, or through special clamping elements such as clamping hubs or shrink discs, both with conical elements. Positive-fit connections, in which force transmission is achieved through a specific shape, e.g., splined shaft profile, polygon profile, toothed shaft profile, and serrations, or through additional drive elements (keys). A distinction is also made here between indirect and direct positive fit. Preloaded positive-fit connections: This combination of the two aforementioned connection types arises, among other things, from the use of keys. Material-fit connections, e.g., through gluing, soldering, or welding.

[0051] The first shaft 10 is rotatably mounted, electrically insulated from a housing 2 of the gearbox 1, by means of bearings 5 ​​and bearing insulators 6, and can be rotationally fixed to an electric machine that can be operated as a motor and / or generator. It is also conceivable to form the first shaft 10 integrally with a shaft of the electric machine.

[0052] The insulating mounting in the housing 2 prevents any current flow from the first shaft 10 into the housing 2, thus protecting the running surfaces and other components of the bearings 5 ​​from corresponding damage or impairment.

[0053] A first tooth 14 of the first gear 13 (pinion) is rotationally fixed to it – for example, by means of a shrink-fit connection – and is in mesh with a second tooth 24 of the second gear 20 (large gear). This establishes an electrical connection between the second tooth 24 and the first tooth 14. Consequently, current could flow from an electric machine via the first shaft 10 and the first gear 13 to the second tooth 24.

[0054] To prevent such a current flow, as shown in Fig. 3, 4 and 5- The second gear 23 is formed in two parts, with an inner section 30 and an outer section 40, wherein insulating means 54 are effectively provided between the inner section 30 and the outer section 40. The outer section 40 is connected to the second gear 24 either in a rotationally fixed manner or integrally. Furthermore, a connecting device 50 is provided between the inner section 30 and the outer section 40 to achieve at least a rotationally fixed connection between the inner section 30 and the outer section 40. In particular, the connecting device 50 is designed such that the inner section 30 and the outer section 40 are completely fixed relative to each other (with respect to all degrees of freedom). The inner section 30 can be formed at least in a rotationally fixed manner or integrally with the second shaft 20.

[0055] The concept described above achieves for the first time that a gear stage of the gearbox 2 connected to an electric machine is completely galvanically separated and electrically isolated from the other components of the gearbox 2 or further gear stages and gears.

[0056] It is also conceivable to design the first gear (pinion) in two parts, analogous to the construction of the second gear 24.

[0057] With the help of Fig. 4 and Fig. 5The detailed construction of the second gear 30 is explained in detail, wherein the inner section 30 of the second gear 20 is partially formed integrally with the second shaft 20. In a region extending radially 3 outwards from the second gear 20, the inner section 30 is at least partially formed as an inner flange 31 with an inner flange surface 32 extending radially 3. Preferably, the inner flange surface 32 is oriented perpendicular to an axial direction 4 of the second gear 23 and extends in a disk-like shape around the entire circumference of the inner section 30.

[0058] Analogous to the inner flange 30, the outer section 40 has an outer flange 41 located radially inside in the direction 3, with an outer flange surface 42. The outer flange surface 42 is oriented perpendicular to the axial direction 4 and extends in a disk shape around an inner circumference of the outer section 40.

[0059] The outer section 40 and the outer flange 41 and the inner section 30 and the inner section 31 are designed and coordinated in such a way that the inner flange surface 32 corresponds to the outer flange surface 42 and these can be aligned facing each other.

[0060] To connect the inner section 30 and the outer section 40, the connecting device 50 is designed with a connecting element 52. This is preferably designed as a screw which, according to the present embodiment, passes through a bore in the outer flange 41 and is screwed into a thread in the inner flange 31. In this way, a normal force acting in the axial direction 3 can be provided to generate a circumferentially acting frictional connection between the inner flange surface 32 and the outer flange surface 42.

[0061] For galvanic isolation between inner section 31 and outer section 41, insulating means 54 are provided at all relevant contact surfaces between them. On the one hand, the insulating means 54 comprise an insulating flange disc ring 55, at least one insulating sleeve 56, and an axial insulating element 57. The flange disc ring 55 serves to galvanically isolate the inner flange surface 32 from the outer flange surface 42 and is preferably designed as a disc-shaped ring around the entire circumference of the inner flange surface 32. Fig. 6 ).

[0062] The flange-disc ring 55 is made of a material and is designed such that it can withstand the surface pressures necessary for frictional engagement and simultaneously exhibits suitable coefficients of adhesion and friction. In particular, the materials and / or surfaces of the flange-disc ring 55 and the inner flange 31 / outer flange 32 are selected such that the corresponding tribological system has a coefficient of friction of at least µ = 0.2, preferably at least µ = 0.3, and more preferably at least µ = 0.4.

[0063] In order to achieve galvanic isolation between the connecting element 52 and an inner wall of the bore in the outer flange 41, the insulating sleeve 56 substantially encompasses the entire circumference of the bore and extends in the axial direction 51 of the connecting element 52 or the bore substantially over the entire depth of the bore.

[0064] An insulating arrangement of a head of the connecting element 52 and a corresponding bearing surface of the outer flange 41 is achieved by the axial insulating element 57 - preferably designed as an insulating washer.

[0065] In the present embodiment, a locking element 53 - preferably designed as a washer - is further provided to keep surface pressures within a permissible range.

[0066] Although specific embodiments have been presented and described herein, it is within the scope of the present invention to modify the illustrated embodiments appropriately without deviating from the scope of protection of the present invention; for example, the connecting device 50 between inner section 30 and outer section 40 can be configured in reverse to the described arrangement, such that a thread for the connecting element 52 is located in the outer flange 41 and a corresponding bore is located in the inner flange 31.

[0067] It is also conceivable that gearbox 1 could be designed with more than one stage. This will be discussed in... Fig. 4 The figure shows that the second shaft 20 of the second gear 23 has a further seating surface 25 for another gear (further pinion) not shown. Reference symbol list

[0068] 1 Gearbox 2 Housing 3 Axial direction 4 Radial direction 5 Bearing 6 Bearing insulation 7 Bearing 10 First shaft 11 First axis of rotation 12 First bearing 13 First gear 14 First ring gear 20 Second shaft 21 Second axis of rotation 22 Second bearing 23 Second gear 24 Second ring gear 25 Seat surface 30 Inner section 31 Inner flange 32 Inner flange surface 33 Inner bore 40 Outer section 41 Outer flange 42 Outer flange surface 43 Outer bore 50 Connecting device 51 Axial direction 52 Fastener / screw 53 Locking element 54 Insulating means 55 Flange washer ring 56 Insulating sleeve 57 Axial insulating element 100 Vehicle 101 Bogie 102 Car body 103 Drive device

Claims

1. Gearing (1) for a drive device (103) for a vehicle, in particular for a rail vehicle (100), comprising: - a housing (2), - a first gear wheel (13) fixed in a rotationally fixed manner on a first shaft (10) with a first gear rim (14), - a second gear wheel (23) fixed in a rotationally fixed manner on a second shaft (20), and - engaging with the first gear wheel (13), with a second gear rim (24), - wherein the first shaft (10) and / or the second shaft (20) are mounted in the housing (2) rotatable and / or electrically insulated from it, - wherein the first gear wheel and / or the second gear wheel (24) is / are formed in at least two parts and comprise a radially inner internal section (30) and, located radially outside thereof, an outer section (40), characterised in that - insulation means (54) are provided for insulating between the internal section (30) and the outer section (40), and - the first gear rim (14) is electrically insulated from the first shaft (10) and / or the second gear rim (24) is electrically insulated from the second shaft (20).

2. Gearing (1) of claim 1, wherein between the first shaft (10) and the first gear rim (14) and / or between the second shaft (20) and the second gear rim (24) insulating means (54) are provided for providing an electrical insulation.

3. Gearing (1) of claim 2, wherein the insulating means are provided in the region of a shaft-hub connection and are carried out as an insulating coating and / or as an insulating bushing.

4. Gearing (1) of one of the preceding claims, wherein the first shaft (10) is carried out as a driving shaft in such a way that it can be connected to a rotative element for rotational power consumption.

5. Gearing (1) of one of the preceding claims, wherein the first shaft (10) is electrically insulated from the housing (2) by means of a bearing insulation (6).

6. Gearing (1) of one of claims 1 to 5, wherein the first gear wheel and / or the second gear wheel (23) comprise(s) a connecting device (50) with connecting means (52), in particular carried out as screw, for connecting the internal section (30) and the outer section (40) at least in a rotationally fixed manner.

7. Gearing (1) of one of claims 1 to 6, wherein the internal section (30) is formed integrally, in particular in one piece, with the respective shaft (20).

8. Gearing (1) of one of the preceding claims, wherein the second gear rim (24) has a greater number of teeth than the first gear rim (14), in particular wherein the second gear wheel (23) is carried out as a large gear wheel.

9. Gearing (1) of one of claims 1 to 8, wherein the internal section (30) comprises an internal flange (31) with an internal flange surface (32) and the outer section (40) comprises an outer flange (41) connected thereto with an outer flange surface (42), and wherein the insulating means (54) comprise at least one insulating flange disc ring (55) which is arranged between the internal flange surface (32) and the outer flange surface (42).

10. Gearing (1) of one of claims 1 to 9, wherein the insulating means (54) comprise at least one insulating sleeve (56) and / or an axial insulating element (57) for insulating a connecting means (52) from the internal section or from the outer section (40).

11. Gearing (1) of one of the preceding claims, wherein the insulating means (54) are manufactured at least partially of plastic, in particular of polyether ether ketone (PEEK), of Vetronite, of aluminium oxide (Al2O3) and / or of oxide fibre-reinforced oxide ceramics.

12. Gear wheel (23) for a gearing (1) according to one of the preceding claims 1 to 11, in particular carried out as a second gear wheel (23), comprising a gear rim (24) configured for engaging with the gear rim (14) of the first gear wheel (13), an outer section (40) connected with the gear rim (24) with an outer flange (41), an internal section (30) connected in a rotatable manner with the outer section (40) in a radial direction (4), a connecting device (50) carried out for connecting the outer section (40) with the internal section (30), and insulating means (54) carried out and arranged such between the internal section (30) and the outer section (40) that the internal section (30) and the outer section (40) are electrically insulated from each other.

13. Drive device for a vehicle, in particular for a rail vehicle (100), comprising - a drive motor, a gearing (1) of one of claims 1 to 11, and an output axle connectable to drive wheels of the rail vehicle (100), - wherein the first shaft (10) of the gearing (1) is rotatably connected to an output shaft of the drive motor and / or a coupling connected thereto, and - wherein an output shaft of the gearing (1) rotatably connected to the first shaft (10) is rotatably connected to the drive axle.

14. Vehicle with a car body (102) and a drive device of claim 13, in particular wherein the vehicle is carried out as a rail vehicle (100), wherein the car body (102) of the rail vehicle (100) can be mounted rollable on rails by means of a bogie (101), and wherein the bogie (101) comprises the drive device.