Transmission device for transmitting an electrical signal

Abstract

Transmission device (1) for the transmission of an electrical signal, in particular an electric current, between a stationary assembly (2), in particular a housing (3, 3'), and a component (4) rotatable relative to the stationary assembly (2), in particular a shaft, wherein a preloading device (9) is configured to generate a preload force to generate static friction and / or rolling friction between a first contact area (6, 6') of the rotatable component (4) and a second contact area (7, 7') of the stationary assembly (2).

Description

[0001] The invention relates to a transmission device for transmitting an electrical signal, in particular an electrical current, between a stationary assembly, in particular a housing, and a component rotatable relative to the stationary assembly, in particular a shaft.

[0002] Transmission devices for transmitting electrical signals, particularly electrical currents, between a stationary assembly and a component that can rotate relative to the stationary assembly, such as a shaft, are generally known in the art. Such transmission devices are implemented, for example, in electric motors for supplying electrical current in the form of sliding contacts, such as carbon brushes that contact slip rings. The disadvantage here is that the sliding friction between the carbon brushes and the slip ring is accompanied by comparatively high friction and wear, which lead to losses and contamination due to abrasion. Furthermore, the described type of contact can result in sparking or problems with electromagnetic compatibility.

[0003] The invention is based on the object of providing an improved transmission device for the transmission of an electrical signal.

[0004] The object is achieved by a transmission device having the features of claim 1. Advantageous embodiments are the subject of the subclaims.

[0005] As described, the invention relates to a transmission device for transmitting an electrical signal, in particular an electrical current, between a stationary assembly, in particular a housing of the transmission device, and a component rotatable relative to the stationary assembly, in particular a shaft. Specifically, the transmission device can be provided for transmitting the electrical signal to an electrical machine. For this purpose, for example, the electrical current can be transmitted between the stationary assembly, for example a stationary housing of the transmission device, and the rotating component, for example the rotor shaft of the electrical machine or a shaft section connected to the rotor shaft.

[0006] The invention is based on the finding that a pretensioning device is provided which is designed to generate a pretensioning force for generating static friction and / or rolling friction between a first contact region of the rotatable component and a second contact region of the stationary assembly. Instead of the solution known in the prior art, in which sliding friction is generated by a sliding contact in which a contact element of the sliding contact contacts the rotating component, for example a carbon brush which is pressed onto a slip ring, the invention proposes that the pretensioning device generates a targeted pretensioning force in order to generate static friction and / or rolling friction between the first contact region of the rotatable component and the second contact region of the stationary assembly.

[0007] This advantageously prevents the generation of sliding friction between the contact partners, significantly reducing friction and wear, thus preventing abrasion and contamination. To generate static friction or rolling friction between the contact areas, a defined rolling action of the rotating component against the stationary assembly is achieved. This prevents the contact areas from grinding or sliding, allowing them to roll against each other in a defined manner.

[0008] According to one embodiment of the transmission device, it can be provided that the rotatable component is designed as a shaft section, in particular one that is connectable or connected to a rotor shaft of an electrical machine, which shaft section has at least the first contact area for contacting the stationary assembly, wherein the first contact area is connectable or connected to an electrical connection of the electrical machine. As already described, the transmission device can be used specifically for transmitting the electrical signal to or into an electrical machine. In this case, the rotatable component can be designed as a shaft section of a rotor shaft or as a shaft section connected to the rotor shaft, or it can comprise one that has the previously described first contact area, through which the electrical contact with the stationary assembly is established.If the electric machine has multiple phases or multiple contact points, multiple contact areas or contact area pairs can be provided so that different electrical signals can be introduced into different contact areas of the rotating component. The rotating component has a connection via the electrical connection of the electric machine, for example, to the rotor, so that the electrical signal can be transmitted there.

[0009] As described, the preloading device ensures that the first contact area rolls on the second contact area by means of static friction and / or rolling friction. In this case, the shaft section rolls on the stationary assembly, for example, on the second contact area connected to the housing, such that the first contact area of ​​the shaft section rolls on the second contact area, thus preventing a sliding or grinding movement.

[0010] The transmission device can further be developed such that the pretensioning device has a spring device, in particular a tension spring, and / or a magnetic device which is designed to generate the pretensioning force between the contact areas. The spring device can, for example, be understood as a tension spring which pretensions the first contact area and the second contact area against one another. The spring device can, in principle, be designed as any compression spring or tension spring, whereby the design as a tension spring can be preferred. It is also possible to use a magnetic device which, as the pretensioning device, generates a magnetic force between the contact areas, which brings the two contact areas together, such that a defined rolling of the contact areas against one another or of one contact area against the other contact area enables and thus prevents sliding friction.

[0011] In a further development of the transmission device, the pretensioning device can be provided with a transmission element that couples a pivot bearing arranged on the rotatable component to a pivotally mounted tensioning pulley adjacent to the stationary assembly, in particular pretensioning it by means of the spring device. Since the rotational speeds or rotational speeds of the rotor shaft or shaft section do not have to match the rotational speeds of the pivotally mounted tensioning pulley, the pivot bearing is arranged on the rotatable component and connected to the pivotally mounted tensioning pulley adjacent to the stationary assembly via the transmission element.

[0012] The pretensioning device, in particular the previously described spring device, can pretension the pivot bearing and the tensioning pulley against each other so that the contact areas on the rotatable component and the stationary assembly are tensioned against each other in such a way that, as described, rolling friction develops and the contact areas roll against each other, thus preventing sliding friction. The transmission element couples the pivot bearing to the tensioning pulley, for example with a spring element of the spring device arranged between a first transmission section of the transmission element and a second transmission section of the transmission element, which spring element couples the two transmission sections to each other and pretensions them against each other. The first transmission section can be connected to the pivot bearing of the rotatable component or the shaft section, and the second transmission element can be coupled to the tensioning pulley.

[0013] The transmission device can be further developed such that the pretensioning device has a compensating element, in particular coupled to the transmission element, which is designed to compensate for an imbalance generated by the pretensioning device on the rotatable component. Since the pretensioning device, in particular the transmission element, the pivot bearing, and the tensioning roller, imposes an imbalance on the shaft section or the rotor shaft, the transmission element is provided, which compensates for the imbalance generated by the pretensioning device. For example, the compensating element can be coupled to the transmission element or represent an extension of the transmission element in the direction opposite the tensioning roller or be designed as such.

[0014] In a further embodiment of the transmission device, the stationary assembly can have a sleeve coupled to a fastening section, which has the second contact area, wherein the first contact area of ​​the component engages in the sleeve. The fastening section can be connected to the housing or form part of the housing. As described, the first contact area can be arranged on the rotatable component, for example, the shaft section. The rotor shaft or the shaft section engages in the sleeve, which is firmly coupled to the stationary assembly.

[0015] The sleeve thus forms the second contact area on its inner circumference, against which the first contact area of ​​the rotatable component can roll. For example, the sleeve can be firmly connected to the housing of the transmission device using the fastening section. Alternatively, the housing itself can be referred to as the fastening section or act as such. In particular, the shaft section can roll with its outer circumference, in particular in a rotatable manner, against the inner circumference of the sleeve. The sleeve thus forms an opening into which the shaft section or, in general, the rotatable component can engage in the axial direction. As described, the pretensioning device effects a pretensioning force sufficient to prevent sliding friction and ensure rolling friction. The pretensioning force is exerted in the radial direction, so that the outer circumference orThe outer surface of the rotating component, in particular its shaft section, is pressed against the inner surface of the sleeve. A reverse arrangement, in which the shaft section rotates around the sleeve, is also possible.

[0016] The described transmission device can be further developed such that the rotatable component has a flexible shaft section which, in particular by means of the prestressing force, is bent from the longitudinal axis of the shaft section to the surface of the second contact area. The shaft section of the rotor shaft or the shaft section connected to the rotor shaft is designed to be flexible in such a way that it is torque-resistant, yet movable or generally deformable. By applying the prestressing force, the shaft section is deflected from a straight alignment on the axis of rotation and pressed or pulled against the second contact area of ​​the stationary assembly. This establishes contact between the contact areas, so that the first contact area can roll on the second contact area. The flexible design of the shaft section can, for example, be designed in the manner of a flexible shaft for hand tools.As described, this should allow deformation, in particular deflection relative to a longitudinal axis of the shaft section or the rotor shaft, but be sufficiently torque-stiff to be able to transmit a rotary movement.

[0017] Furthermore, the transmission device can be provided with the second contact region of the fixed assembly being movably mounted relative to a base body of the fixed assembly. For example, as an alternative to the previously described flexible design of the shaft section, a movement can be carried out by the sleeve of the fixed assembly. The fixed assembly remains stationary and does not carry out any movement with respect to its base body, in particular the housing, but the second contact region of the fixed assembly is movable relative to the base body. The second contact region can be mounted in such a way, in particular flexibly, that, for example, the previously described sleeve can move relative to the remaining housing of the fixed assembly.The second contact area can be movable, for example, like an XY table, so that the second contact area does not perform a rotational movement, but can be moved along with the rotating first contact area of ​​the rotatable component. In this case, the rotatable component always performs the rotational movement, which leads to the first contact area rolling against the second contact area. The second contact area is only moved along with the movement of the first contact area in a plane perpendicular to the axis of the shaft section.

[0018] Specifically, it can be provided that the second contact area of ​​the stationary assembly is arranged on the base body of the stationary assembly by means of a cross-slide bearing. The cross-slide bearing can, in particular, have a longitudinal guide and a transverse guide, so that the second contact area can always be moved with the movement of the rotatable component, for example, in an XY plane. Contacting for transmitting the electrical signal can be implemented, in particular, with a flexible wire or a flexible connecting element that can flexibly adapt to the movement or current position of the sleeve or the second contact area.

[0019] In addition to the transmission device, the invention relates to a motor vehicle comprising an electric machine and a previously described transmission device. Furthermore, the invention relates to a method for transmitting an electrical signal, in particular an electrical current, between a stationary assembly, in particular a housing, and a component rotatable relative to the stationary assembly, in particular a shaft, wherein a prestressing device generates a prestressing force to generate static friction and / or rolling friction between a first contact area of ​​the rotatable component and a second contact area of ​​the stationary assembly.

[0020] All advantages, details and features described with regard to the transmission device are fully transferable to the motor vehicle and the method.

[0021] The invention is explained below using exemplary embodiments with reference to the figures. The figures are schematic representations and show: Fig. 1 a perspective view of a transmission device according to a first embodiment; Fig. 2 the transmission device of Fig. 1 in a side view; Fig. 3 the transmission device of Fig. 1, Fig. 2 in a sectioned, perspective view; Fig. 4 a perspective view of a transmission device according to a second embodiment; Fig. 5 the transmission device of Fig. 4 in a lateral, sectional view; Fig. 6 is a perspective view of a transmission device according to a third embodiment; and Fig. 7 the transmission device of Fig. 6 in a perspective, sectional view.

[0022] Fig. 1 shows a schematic diagram of a transmission device 1 for transmitting an electrical signal, in particular an electrical current, according to a first exemplary embodiment. The transmission device 1 has a stationary assembly 2, which, for example, comprises a housing 3. The transmission device 1 is designed to transmit the electrical signal between the stationary assembly 2 and a component 4 that is rotatable relative to the stationary assembly 2. The rotatable component 4 has, for example, a shaft section 5, which can be connected to a rotor shaft in order to transmit the electrical signal to the electrical machine via the rotor shaft.

[0023] In other words, the shaft section 5 or the rotatable component 4 is rotatable relative to the stationary assembly 2, wherein the rotatable component 4 has a first contact region 6 on the shaft section 5, which is in contact with a second contact region 7 of the stationary assembly 2. For this purpose, the stationary assembly 2 has, for example, a sleeve 8, on the inner circumference or inner surface of which the second contact region 7 is formed. The sleeve 8 can be connected to a base body or a fastening section of the housing 3. The first contact region 6, which is formed or arranged on an outer circumference or an outer surface of the shaft section 5 of the rotatable component 4, can thus roll on the inner surface of the sleeve 8 or the second contact region 7.

[0024] In order to ensure a sufficient preload force between the two contact areas 6, 7 so that sliding friction is prevented and static friction and / or rolling friction can be generated between the contact areas 6, 7 instead, the transmission device 1 has a preload device 9. The preload device 9 in turn has a spring device 10 which preloads the first contact area 6 and the second contact area 7 against one another. Alternatively, the preload device 9 can also have a magnetic device (not shown in detail). The spring device 10 has a spring element 11, which is designed, for example, as a tension spring. The coupling between the rotatable component 4, in particular its shaft section 5, and the stationary assembly 2, in particular the sleeve 8, is established via a transmission element 12 which has a first transmission section 13 and a second transmission section 14.

[0025] The first transmission section 13 and the second transmission section 14 are thus movably mounted relative to one another, so that a preload force can be exerted between the two transmission sections 13, 14 by means of the spring element 11. A pivot bearing 15 is also provided on the shaft section 5, with a pivotally mounted tensioning roller 16 being provided on the second transmission element 14. An imbalance caused by the preload device 9 on the rotatable component 4 is compensated for by a compensating element 20, which is also connected to the transmission element 12, for example, extending the transmission element 12 in the direction opposite the transmission sections 13, 14.

[0026] As in Fig. 1-3, the rotor shaft, which is coupled to the shaft section 5, is rigid and inflexible, so that it can transmit torque to or from the corresponding gear elements without significantly deforming. In the first embodiment, which is shown in Fig. 1-3, as well as in the second embodiment described below, which is shown in Fig. 4, Fig. 5, the shaft section 5 is flexible and torque-resistant. This means that torque can still be transmitted without generating twisting about the longitudinal axis, but the shaft section 5 is sufficiently deformable, in particular in an XY plane perpendicular to the longitudinal axis of the shaft section 5, so that by means of the pretensioning device 9 the shaft section 5 can be shaped against the sleeve 8 such that the contact regions 6, 7 abut one another and sufficient pretensioning force can be transmitted so that the tensioning roller 16 and the shaft section 5 roll on the sleeve 8, namely the tensioning roller 16 on the outer circumference and the first contact region 6 on the second contact region 7 on the inner circumference of the sleeve 8. A reversal of the arrangement shown, in which the first contact region 6 rotates outside around the second contact region 7, which is arranged on the outer surface of the sleeve 8, is also possible.

[0027] As in Fig. As shown in Figure 2, the shaft section 5 is flexibly bent away from the axis of rotation or deflected from its longitudinal orientation by the pretensioning device 9 and pressed or pulled against the inner circumference of the sleeve 8. As described, the sleeve 8 is connected to the housing 3 of the transmission device 1 and is therefore fixed, i.e., the sleeve 8 does not rotate. For example, the housing 3 of the transmission device 1 can be connected to a housing (not shown in detail) of the electrical machine into which the electrical signal is to be transmitted.

[0028] When the shaft section 5 rotates together with the rotor shaft, the first contact area 6 is pressed against the second contact area 7 by means of the spring device 10, namely the spring element 11. The preload force is supported by the tension roller 16 on the outer surface of the sleeve 8, and the first contact area 6 is thus pulled or pressed against the second contact area 7. Since the shaft section 5 is flexible, it can be bent or deformed as desired in the radial direction, while the rotor shaft can rotate underneath it. As a result, the shaft section 5 can roll as desired along the inner circumference or inner surface of the sleeve 8, whereby the two contact areas 6, 7 can always be connected to one another.Accordingly, the sleeve 8 is electrically contacted, so that the electrical signal can be guided from the second contact area 7 into the first contact area 6 via the sleeve 8 and can thus be guided via the shaft section 5 into the rotor shaft and from there into the electrical machine, for example into the rotor.

[0029] As in Fig. 4, Fig. 5 in the second exemplary embodiment, it is possible to realize a plurality of contact points at different first contact regions 6, 6' and second contact regions 7, 7' by providing an additional sleeve 8'. In order to introduce various electrical signals, for example for multi-phase electrical machines, into the electrical machine, the number of sleeves 8, ' as well as first contact regions 6, 6' and second contact regions 7, 7' can be expanded as desired. The first contact regions 6, 6' and second contact regions 7, 7' on the sleeve 8 or the shaft section 5 are then to be designed to be insulated from one another. As can be seen, the sleeves 8, 8' are arranged adjacent to one another in the axial direction; the individual shaft sections 5, 5' can deform in different directions and can generally be independent of one another with regard to the deformation movement.The individual subunits of the transmission device 1 can be identical to the embodiment in . Fig. 1-3, which means that the individual shaft sections 5, 5' are preloaded against the respective sleeve 8, 8' by their own preloading devices 9.

[0030] Fig. 6, Fig. Figure 7 shows a transmission device 1 in a third embodiment. The basic operation is different from the previous embodiments with reference to Fig. 1-5 transferable. Deviating from the previous description, here the shaft section 5 is rigid and not flexible, instead the sleeve 8 is flexible or movably mounted together with the housing 3 within the housing 3, ie the sleeve 8 is not movable relative to the housing 3, but movable together with the housing 3 and therefore immovably mounted relative to the housing 3. The sleeve can be moved linearly, whereby it is fixed with respect to rotational movements and thus cannot rotate with the shaft section 5. Purely as an example, in Fig. 6, Fig. 7 shows a cross slide bearing 17, wherein a longitudinal guide 18 and a transverse guide 19 are provided, which movably support the housing 3 and the sleeve 8 arranged therein, for example in the X-direction and Y-direction, wherein the Z-direction can, for example, describe the longitudinal axis of the shaft section 5 or be aligned parallel to it.

[0031] For the sake of clarity, Fig. 6, Fig. 7 the pre-tensioning device 9 is hidden, which, for example, is analogous to Fig. 1-3. In any case, the preload force on the shaft section 5 is effected in such a way that it can roll on the inner circumference of the sleeve 8, i.e. that static friction and / or rolling friction is generated between the first contact area 6 and the second contact area 7 such that the shaft section 5 rolls on the inner surface of the sleeve 8 and a sliding or grinding movement is prevented. The sleeve 8 moves in the X direction and Y direction such that the contact connection between the first contact area 6 and the second contact area 7 is always maintained. The sleeve 8 can in particular be contacted by a flexible connecting element (not shown), for example a flexible wire, which can carry out the XY movement of the shaft section 5 or the longitudinal guide 18 and transverse guide 19. Reference symbol 1 transmission device 2 fixed assembly 3.3' housing 4 rotating component 5.5' wave section 6, 6' first contact area 7, 7' second contact area 8, 8' sleeve 9 Pre-tensioning device 10 Spring device 11 Spring element 12 transmission element 13 first transmission section 14 second transmission section 15 pivot bearings 16 tension pulley 17 Cross slide bearing 18 Longitudinal guide 19 Transverse guide 20 Compensating element

Claims

[1] Transmission device (1) for the transmission of an electrical signal, in particular an electrical current, between a fixed assembly (2), in particular a housing (3, 3'), and a component (4) rotatable relative to the fixed assembly (2), in particular a shaft, characterized by a pretensioning device (9) which is designed to generate a pretensioning force for generating static friction and / or rolling friction between a first contact region (6, 6') of the rotatable component (4) and a second contact region (7, 7') of the fixed assembly (2). [2] Transmission device (1) according to claim 1, characterized byin that the rotatable component (4) is designed as a shaft section (5, 5'), in particular connectable or connected to a rotor shaft of an electrical machine, which shaft section (5, 5') has at least the first contact region (6, 6') for contacting the stationary assembly (2), wherein the first contact region (6, 6') is connectable or connected to an electrical connection of the electrical machine. [3] Transmission device (1) according to claim 1 or 2, characterized by that the pretensioning device (9) has a spring device (10), in particular a tension spring, and / or a magnetic device which is designed to generate the pretensioning force between the contact areas (6, 6', 7, 7'). [4] Transmission device (1) according to one of the preceding claims, characterized bythat the pretensioning device (9) has a transmission element (12) which connects a rotary bearing (15) arranged on the rotatable component (4) to a tensioning roller (16) which is rotatably mounted and rests on the fixed assembly (2), in particular pretensioning it by means of the spring device (10). [5] Transmission device (1) according to one of the preceding claims, characterized by that the pretensioning device (9) has a compensating element (20), which is coupled in particular to the transmission element (12) and is designed to compensate for an imbalance on the rotatable component (4) generated by the pretensioning device (9). [6] 6'. Transmission device (1) according to one of the preceding claims, characterized byin that the fixed assembly (2) has a sleeve (8) coupled to a fastening section, which has the second contact region (7, 7'), wherein the first contact region (6, 6') of the rotatable component (4) engages in the sleeve (8). [7] 7'. Transmission device (1) according to one of the preceding claims, characterized by that the rotatable component (4) has a flexible shaft section (5, 5') which, in particular by means of the prestressing force, is bent from the longitudinal axis of the shaft section (5, 5') to the surface of the second contact region (7, 7'). [8] Transmission device (1) according to one of the preceding claims, characterized by that the second contact area (7, 7') of the fixed assembly (2) is movably mounted relative to a base body of the fixed assembly (2). [9] Transmission device (1) according to claim 8, characterized bythat the second contact area (7, 7') is arranged on the base body of the fixed assembly (2) by means of a cross slide bearing (17). [10] Motor vehicle comprising an electric machine and a transmission device (1) according to one of the preceding claims. [11] Method for transmitting an electrical signal, in particular an electrical current, between a fixed assembly (2), in particular a housing (3, 3'), and a component (4), in particular a shaft, which is rotatable relative to the fixed assembly (2), characterized by that a pre-tensioning force for generating static friction and / or rolling friction between a first contact area (6, 6') of the rotatable component (4) and a second contact area (7, 7') of the fixed assembly (2) is generated by means of a pre-tensioning device (9).

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