Traction machine and vehicle

Abstract

A traction machine (20) has a rotor arrangement (80), a stator arrangement (60), an inverter (14), a control device (12), a radial bearing (40), a linear bearing (50), and an adjusting device (30), wherein the rotor arrangement (80) has a rotor core (82) and permanent magnets (84), wherein the stator arrangement (60) has a stator core (62) and a winding arrangement (64), wherein the adjusting device (30) is designed to carry out the first displacement (52) into a first axial relative position (P1) upon receipt of a first control signal (SIG1) with first information, and to enable the displacement (52) into a second axial relative position (P2) upon receipt of the first control signal (SIG1) with second information, wherein in the first axial relative position (P1) the axial overlap between the rotor core (82) and the stator core (62) is greater than in the second axial relative position (P2).

Description

[0001] The invention relates to a traction machine and a vehicle.

[0002] DE 10 2020 114 856 B3 shows an electric motor with a stator and a rotor, wherein the rotor is axially displaceable relative to the stator.

[0003] WO 2010 / 052 177 A1 shows an electric motor with an axially movable rotor.

[0004] DE 10 2006 020 867 A1 shows an electric machine in which the rotor and the stator can be moved relative to each other to weaken the field.

[0005] EP 2 306 621 A1 shows an electric motor with a stator and a rotor, wherein the rotor is mounted in a floating manner.

[0006] DE 10 2020 123 345 A1 shows an electrical machine with a variable air gap width.

[0007] DE 10 2012 201 347 A1 shows an electric machine with detuning means for shifting the rotor and stator relative to each other.

[0008] JP 2008 - 131 790 A shows an electric machine with a solution for reducing an electromotive force by axial displacement of the rotor depending on the speed.

[0009] DE 20 2023 106 333 U1 shows an electric machine with a spring arrangement which is coupled to a first side of the rotor and exerts a first axial force on the rotor, and a gear arrangement which exerts a second, opposite axial force, wherein the second axial force corresponds to the rotor torque.

[0010] DE 10 2017 221 103 A1 shows an electric machine for driving a compressor, in which the stator can be displaced relative to the rotor in a direction parallel to the axis of rotation, wherein the stator can be displaced parallel to the axis of rotation by actuating an actuator.

[0011] US 7 863 789 B2 shows a permanent magnet motor with an actuator for axial movement of the rotor relative to the stator.

[0012] It is therefore an object of the invention to provide a new traction machine and a new vehicle.

[0013] This problem is solved by the subject matter of claim 1 and the subordinate claim.

[0014] A traction machine comprises a rotor arrangement, a stator arrangement, an inverter, a control device, a radial bearing, a linear bearing, and an adjusting device, wherein the rotor arrangement comprises a rotor core and permanent magnets, wherein the stator arrangement comprises a stator core and a winding arrangement, wherein the radial bearing is designed to enable rotation of the rotor arrangement relative to the stator arrangement, wherein the linear bearing is designed to enable a first displacement of the rotor core with the permanent magnets relative to the stator core with the winding arrangement in the axial direction, wherein the adjusting device is designed to carry out the first displacement into a first axial relative position upon receipt of a first control signal with first information and to carry out the displacement into a second axial relative position upon receipt of the first control signal with second information,wherein in the first axial relative position the axial overlap between the rotor core and the stator core is greater than in the second axial relative position, and wherein the control device has a first state and a second state, and wherein the control device is designed to - in the first state, to output the first control signal with the first information and to energise the winding arrangement at least temporarily by means of the inverter in order to effect a torque transmission between the stator arrangement and the rotor arrangement, and - in the second state, output the first control signal with the second information to reduce the torque transmission between the rotor assembly and the stator assembly compared to the first axial relative position. Interaction between the rotor assembly and the stator assembly is at least reduced in the second position, and as a result, a vehicle with such a traction machine can move with little influence from the traction machine. This can also be referred to as a freewheel function.

[0015] According to a preferred embodiment, the control device is designed not to actively supply current to the winding arrangement by the inverter in the second state.

[0016] According to a preferred embodiment, the traction machine is designed as a permanent magnet synchronous machine. This type has a high level of efficiency.

[0017] According to a preferred embodiment, the adjusting device is designed to displace the rotor assembly. The rotor assembly is typically lighter than the stator assembly, which facilitates displacement.

[0018] The rotor assembly is connected to a shaft, the shaft having a first helical outer groove, and the adjusting device comprising a pin and a movement arrangement for the pin. The adjusting device is configured to engage the pin with the first helical outer groove to cause an axial movement of the rotor assembly upon rotation of the rotor assembly. Such an adjusting device allows a high force to be exerted on the shaft.

[0019] According to a preferred embodiment, the first helical outer groove transitions into a circular outer groove to define an axial end position at the circular outer groove. The displacement ends at the circular outer groove, similar to a record.

[0020] According to a preferred embodiment, the first helical outer groove has a first pitch, and the shaft has a second helical outer groove with a second pitch, wherein the first pitch and the second pitch extend in different directions to enable axial displacement of the shaft in both directions. Thus, in one direction of rotation of the shaft, a transition to the first relative position or to the second relative position can be performed by selecting the corresponding outer groove.

[0021] According to a preferred embodiment, the traction machine comprises a shaft, wherein the rotor assembly is connected to the shaft for axial displacement, and wherein the adjusting device is configured to displace the rotor assembly relative to the shaft in order to switch between the first axial relative position and the second axial relative position. This prevents displacement of the shaft and enables mechanically simpler solutions on the output side.

[0022] According to a preferred embodiment, the adjustment device is designed to displace the stator assembly to switch between the first axial relative position and the second axial relative position. Such a displacement is mechanically simple since the stator assembly does not rotate.

[0023] According to a preferred embodiment, the traction machine has a spring element, wherein the spring element is designed to apply a force to the rotor assembly in an axial direction. This allows the adjustment device to be designed such that it acts only in one direction. Upon deactivation of the adjustment device, the rotor assembly can be moved back again by the spring element.

[0024] According to a preferred embodiment, the rotor assembly is designed as an inner rotor assembly and the stator assembly as an outer stator assembly. This facilitates movement of the rotor assembly relative to the stator assembly.

[0025] According to a preferred embodiment, the rotor arrangement is connected to a shaft, and the shaft is connected to a component to be driven via a coupling, wherein the coupling is designed as a coupling with length compensation in order to enable continuous torque transmission between the shaft and the component when the shaft is displaced.

[0026] A vehicle has such a traction motor. Such a vehicle can operate in neutral without an additional clutch.

[0027] According to a preferred embodiment, the control device is designed to select the second state at least temporarily during coasting. During coasting, the vehicle should continue to roll, with the traction motor exerting as little influence as possible.

[0028] Further details and advantageous developments of the invention will become apparent from the exemplary embodiments described below and illustrated in the drawings, which are in no way to be understood as limiting the invention, as well as from the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention. It shows: Fig. 1 shows a schematic representation of a vehicle with a traction machine in a first state, Fig. 2 shows a schematic representation of a vehicle with a traction machine in a second state, Fig. 3 in a detailed view a further development of the traction machine, Fig. 4 in a detailed view a further development of the traction machine, and Fig. 5 shows a detailed view of a further development of the traction machine.

[0029] In the following, identical or functionally identical parts are provided with the same reference symbols and are usually described only once. The description builds on each figure to avoid unnecessary repetition.

[0030] Fig. 1 shows a schematic representation of a vehicle 10 with a traction machine 20 as used in vehicles for propulsion.

[0031] The traction machine 20 has a rotor assembly 80, a stator assembly 60, an inverter 14, a traction battery 16, a control device 12, a radial bearing 40, a linear bearing 50, and an adjustment device 30.

[0032] The rotor assembly 80 has a rotor core 82 and permanent magnets 84. In the exemplary embodiment, the rotor core 82 is designed as a laminated core.

[0033] In the exemplary embodiment, the rotor arrangement 80 is connected to a shaft 88 for storage purposes.

[0034] The stator assembly 60 has a stator core 62 and a winding assembly 64. In the exemplary embodiment, the stator core 62 is designed as a laminated core. The winding ends of the winding assembly are schematically visible at the axial ends of the stator core 62. The winding assembly 64 is preferably arranged in slots of the stator core 62 in certain regions.

[0035] Through the interaction of the winding arrangement 64 and the permanent magnets 84, a torque can be generated between the rotor arrangement 80 and the stator arrangement 60

[0036] The traction machine 20 is preferably designed as a permanent magnet synchronous machine.

[0037] Preferably, the traction machine 20 is designed as a three-phase traction machine. This enables torque generation at any position of the rotor assembly 80.

[0038] Preferably, the rotor assembly 80 is designed as an inner rotor assembly and the stator assembly 60 as an outer stator assembly. This facilitates axial displacement of the rotor assembly 80.

[0039] The torque can be transmitted via the shaft 88 to a component, for example to a wheel of the vehicle 10 or to a drive shaft of the vehicle 10.

[0040] The inverter 14 is connected to the traction battery 16 to transfer energy from the traction battery 16 to the winding arrangement 64 (e.g. during propulsion) or vice versa (e.g. during recuperation).

[0041] The radial bearing 40 is designed to enable rotation 86 of the rotor assembly 80 relative to the stator assembly 60.

[0042] The linear bearing 50 is designed to enable axial displacement of the rotor assembly 80 relative to the stator assembly 60. When the rotor assembly 80 is displaced relative to the stator assembly 60 using the linear bearing 50, either simultaneous rotation of the shaft 88 relative to the stator assembly 60 may be possible or not.

[0043] The adjusting device 30 is designed to carry out a displacement 52 into a first axial relative position P1 upon receipt of a first control signal SIG1 with a first piece of information and to carry out a displacement 52 into a second axial relative position P2 upon receipt of the first control signal SIG1 with a second piece of information (cf. Fig. 2), wherein in the first axial relative position P1 the axial overlap between the rotor arrangement 80 and the stator arrangement 60 is greater than in the second axial relative position P2 (cf. Fig. 2).

[0044] The control device 12 has a first state S1 and a second state S2 (cf. Fig. 2) appears.

[0045] The control device 12 is configured to output the first control signal SIG1 with the first information in the first state S1 and to supply current to the winding arrangement 64 at least temporarily via the inverter 14 in order to generate torque between the stator arrangement 60 and the rotor arrangement 80. The output can be made once; it does not have to be continuous.

[0046] By outputting the first control signal SIG1 with the first information, the rotor arrangement is brought into the first position P1 by the adjusting device 30, if this is not already the case.

[0047] Torque generation is possible because the rotor assembly 80 and the stator assembly 60 axially overlap, and a driving or braking torque can be generated by energizing the winding assembly 64.

[0048] In the exemplary embodiment, the adjustment device 30 is designed to displace the rotor assembly 80. The stator assembly 60 can retain its position in the vehicle 10. This is advantageous because the stator assembly 60 is typically heavier than the rotor assembly 80.

[0049] In the exemplary embodiment, the shaft 88 has a helical outer groove 91.

[0050] The adjusting device 30 has a pin 32 and a movement arrangement 34 for the pin 32.

[0051] With the movement arrangement 34, the pin 32 can be moved toward or away from the shaft 88.

[0052] The adjusting device 30 is designed to bring the pin 32 into engagement with the helical outer groove 91 in order to cause a movement of the rotor arrangement 80 with an axial portion 52 upon rotation of the rotor arrangement 80 and thus also of the shaft 88.

[0053] Preferably, the helical outer groove (91) merges into a circular outer groove 94 in order to define an axial end position on the circular outer groove 94.

[0054] In one embodiment, the linear bearing 50 is designed such that the shaft 88 can perform an axial movement within the linear bearing 50, but without an active axial movement of the shaft 88, a clamping effect exists between the linear bearing 50 and the shaft 88. For this purpose, the linear bearing 88 can be designed as a sleeve that allows axial displacement but holds the shaft 88 in its current position without external axial forces.

[0055] The linear bearing is preferably designed to prevent relative rotation to the shaft 88. For this purpose, for example, the linear bearing 50 can have a radial projection that engages in an axial groove of the shaft 88. Depending on the application, relative rotation may also be permitted, with a separation preferably being made between the functions of the radial bearing 40 and the axial bearing 50.

[0056] Fig. 2 shows the traction machine 20 of Fig. 1 with axially shifted rotor arrangement 80.

[0057] The control device 12 is configured to output the first control signal SIG1 with the second information in the second state S2 in order to reduce the torque transmission between the rotor assembly 80 and the stator assembly 60 relative to the first axial relative position P1. The first control signal SIG1 can be output once after the transition to the second state; therefore, it does not have to be output continuously.

[0058] Due to the axial offset of the rotor arrangement 80 relative to the stator arrangement 60 in the second axial relative position P2, the maximum possible magnetic flux between them is greatly reduced compared to that of the first axial relative position.

[0059] This reduces or prevents any influence on the torque transmission by energizing the winding arrangement 64.

[0060] Secondly, the effect of a voltage induced in the winding arrangement 64 by the rotating rotor arrangement 80 is also reduced. Since the semiconductor switches in the inverter 14 usually have freewheeling diodes to prevent destruction by a current in the reverse direction of the semiconductor switch, even with non-conductive semiconductor switches, a current flows through the winding arrangement due to the induced voltage, which, according to Lenz's law, leads to a magnetic flux that exerts a braking torque on the rotor arrangement 80 with the permanent magnets 84. Since the voltage induced in the winding arrangement 64 by the rotating rotor arrangement 80 is at least significantly reduced due to the axial displacement, the braking of the rotor arrangement 80 is also at least significantly reduced.

[0061] The control device 12 is preferably designed to select the second state S2 at least temporarily in sailing operation.

[0062] During coasting, the vehicle 10 should be allowed to roll freely. The available kinetic energy should be utilized as fully as possible for propulsion. Braking of the vehicle 10 by the traction motor should therefore be minimized. The influence of the traction motor 20 on the torque can also be regulated to 0 Nm by applying appropriate current. However, this requires additional energy from the traction battery 16, and it will not work if the traction battery 16 is empty.

[0063] Sailing operation can also be described as freewheeling, since the vehicle can move largely without being influenced by the traction engine.

[0064] It is particularly advantageous if, in the second position P2, the rotor assembly 80 and the stator assembly 60 have no axial overlap. This results in very little interaction.

[0065] It is very advantageous if, in the second position P2, the rotor core 82 and the stator core 62 have no axial overlap. This results in minimal interaction.

[0066] Even a reduction of the overlap in the area of ​​a partial overlap, in which only a region of the rotor core 82 does not overlap with the stator core 62, already leads to a significant reduction of the interaction.

[0067] The specialist will select one of these three variants for the specific field of application.

[0068] Preferably, the control device 12 is configured not to actively supply current to the winding arrangement 64 through the inverter 14 in the second state S2. This reduces the electrical power loss, since no strong torque transmission is possible.

[0069] Fig. 3 shows another embodiment of the shaft 88.

[0070] The shaft 88 has the helical outer groove 91 with a first pitch and an additional helical outer groove 92 with a second pitch. The pitches can be defined, like a thread pitch, as the axial path traveled by the helical outer groove 91 during rotation of the shaft 88.

[0071] The first pitch and the second pitch run in different directions to allow axial displacement of the shaft 88 in both directions when the shaft 88 rotates in one direction. The corresponding outer groove 91 or 92 can be selected using the adjustment device 30.

[0072] The outer grooves 91, 92 can also be provided on different axial sides of the shaft 88, in which case the adjusting device 30 must also be provided on the second axial side.

[0073] Fig. 4 shows a further advantageous embodiment in which the traction machine 20 has a spring element 96, wherein the spring element 96 is designed to apply a force F to the rotor arrangement 80 in an axial direction.

[0074] In the exemplary embodiment, the rotor assembly 80 is firmly connected to the shaft 88, and by pulling on the shaft 88, the rotor assembly 80 is also subjected to the force F. Alternatively, the spring element 96 can introduce the spring force directly onto the rotor assembly 80.

[0075] A rotary coupling 97 is provided to transmit only the axial portion of the movement of the shaft 88 to the spring element 96. Alternatively, the spring element 96 can be attached to both sides of the rotating system.

[0076] The second side of the spring element 96 is preferably attached to a stationary part 98, for example to a housing part of the traction machine 20.

[0077] Fig. 5 shows the traction machine 20 in the area of ​​the output side of the shaft 88.

[0078] The shaft 88 is connected to a driven component 120 via a coupling 110. The coupling 110 is designed as a length-compensating coupling to enable continuous torque transmission between the shaft 88 and the component 120 when the shaft 88 is displaced.

[0079] In the exemplary embodiment, the shaft 88 has a groove 89. The coupling 110 has a sleeve-shaped portion with an inwardly projecting projection 112 that engages the groove 89. This provides additional anti-rotation protection.

[0080] Alternatively, the shaft and the sleeve-shaped section can have a non-circular cross-section, which also ensures that they are protected against rotation relative to each other.

[0081] Alternatively, the shaft 88 may have a sleeve-shaped section and the coupling component 110 may protrude into the shaft.

[0082] Naturally, various variations and modifications are possible within the scope of the present invention.

[0083] The adjustment device 30 can be configured to displace the stator assembly 60 instead of the rotor assembly 80. This is advantageous because the stator assembly 60 does not perform a rotational movement, and therefore the axial displacement can be easily achieved via a guide and an actuator. Furthermore, the shaft 88 can remain axially unchanged, thereby facilitating the connection to a component 120 to be driven or braked.

[0084] The adjusting device 30 can be designed to displace the rotor assembly 80 relative to the stator assembly 60 and relative to the shaft 88. For this purpose, the rotor assembly 80 is preferably displaceably attached to the shaft 88, for example via a linear guide. The displacement relative to the shaft 88 can be effected, for example, via an actuator connected to the shaft, or it can be effected via a stationary actuator that exerts an axial force on the rotor assembly 80. This is advantageous because the shaft 88 remains axially unchanged, and this facilitates the connection to a component 120 to be driven or braked. In addition, the shaft 88 can be made comparatively short.

Claims

[1] Traction machine (20) comprising a rotor assembly (80), a stator assembly (60), an inverter (14), a control device (12), a radial bearing (40), a linear bearing (50) and an adjusting device (30), wherein the rotor assembly (80) comprises a rotor core (82) and permanent magnets (84), wherein the stator assembly (60) comprises a stator core (62) and a winding assembly (64), wherein the radial bearing (40) is designed to enable a rotation (86) of the rotor arrangement (80) relative to the stator arrangement (60), wherein the linear bearing (50) is designed to enable a first displacement of the rotor core (82) with the permanent magnets (84) relative to the stator core (62) with the winding arrangement (64) in the axial direction, wherein the adjusting device (30) is designed to carry out the first displacement (52) into a first axial relative position (P1) upon receipt of a first control signal (SIG1) with a first piece of information and to carry out the displacement (52) into a second axial relative position (P2) upon receipt of the first control signal (SIG1) with a second piece of information, wherein in the first axial relative position (P1) the axial overlap between the rotor core (82) and the stator core (62) is greater than in the second axial relative position (P2), and wherein the control device (12) has a first state (S1) and a second state (S2), and wherein the control device (12) is designed to - in the first state (S1), to output the first control signal (SIG1) with the first information and to energise the winding arrangement (64) at least temporarily by means of the inverter (14) in order to generate torque between the stator arrangement (60) and the rotor arrangement (80), and - in the second state (S2), output the first control signal (SIG1) with the second information in order to reduce the torque transmission between the rotor arrangement (80) and the stator arrangement (60) compared to the first axial relative position (P1), wherein the rotor arrangement (80) is connected to a shaft (88), wherein the shaft (88) has a first helical outer groove (91), and wherein the adjusting device (30) has a pin (32) and a movement arrangement (34) for the pin (32), wherein the adjusting device (30) is designed to bring the pin (32) into engagement with the first helical outer groove (91) in order to bring about a movement of the rotor arrangement (80) with an axial component (52) upon rotation of the rotor arrangement (80). [2] Traction machine (20) according to claim 1, wherein the control device (12) is designed not to actively supply current to the winding arrangement (64) by the inverter (14) in the second state (S2). [3] Traction machine (20) according to claim 1 or 2, which is designed as a permanent magnet synchronous machine. [4] Traction machine (20) according to one of the preceding claims, wherein the adjusting device (30) is designed to displace the rotor arrangement (80). [5] Traction machine (20) according to one of the preceding claims, wherein the first helical outer groove (91) merges into a circular outer groove (94) to define an axial end position on the circular outer groove (94). [6] Traction machine (20) according to one of the preceding claims, wherein the first helical outer groove (91) has a first pitch, wherein the shaft (88) has a second helical outer groove (92) with a second pitch, the first pitch and the second pitch extending in different directions to enable axial displacement of the shaft (88) in both directions. [7] Traction machine (20) according to one of the preceding claims, which has a shaft (88), wherein the rotor assembly (80) is axially displaceably connected to the shaft (88), and wherein the adjusting device (30) is designed to displace the rotor assembly (80) relative to the shaft (88) in order to change between the first axial relative position (P1) and the second axial relative position (P2). [8] Traction machine (20) according to one of the preceding claims, wherein the adjusting device (30) is designed to displace the stator arrangement (60) in order to change between the first axial relative position (P1) and the second axial relative position (P2). [9] Traction machine (20) according to one of the preceding claims, which has a spring element (96), wherein the spring element (96) is designed to apply a force (F) to the rotor arrangement (80) in an axial direction. [10] Traction machine (20) according to one of the preceding claims, in which the rotor arrangement (80) is designed as an inner rotor arrangement and the stator arrangement (60) is designed as an outer stator arrangement. [11] Traction machine (20) according to one of the preceding claims, in which the rotor arrangement (80) is connected to a shaft (88), and in which the shaft (88) is connected to a component (120) to be driven via a coupling (110), wherein the coupling (110) is designed as a coupling (110) with length compensation in order to enable a continuous torque transmission between the shaft (88) and the component (120) when the shaft (88) is displaced. [12] Vehicle (10) comprising a traction machine (20) according to one of the preceding claims. [13] Vehicle (10) according to claim 12, wherein the control device (12) is designed to select the second state (S2) at least temporarily in sailing operation.

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