RANGE EXTENDER FOR AN ELECTRIC MOTOR-POWERED VEHICLE

Abstract

Range extender for an electric motor-driven vehicle, with an internal combustion engine (4), with a generator (6), wherein the internal combustion engine (4) is designed to drive the generator (6) and wherein the internal combustion engine (4) is coupled to the generator (6) by means of a mechanical interface (8), wherein the interface (8) has a flexplate (8), wherein the flexplate (8) is screwed to a crankshaft (10) of the internal combustion engine (4) and wherein the flexplate (8) is screwed to a rotor (12) or a rotor carrier (40) of the generator (6).

Description

[0001] The present invention relates to a range extender for an electric motor-driven vehicle.

[0002] Range extenders are used to extend the range of electric motor-driven vehicles by charging the traction battery, which supplies the electric motor with electrical power, using an internal combustion engine.

[0003] A range extender can also be called a “range extender” in German, although the English term “range extender” has become established as a technical term in German-speaking countries.

[0004] The present invention aims to provide an improved range extender for an electric motor-driven vehicle, which in particular enables a compact, cost-effective design while simultaneously reliably coupling the combustion engine with the generator.

[0005] According to the invention, a range extender for an electric motor-driven vehicle is specified, comprising an internal combustion engine and a generator, wherein the internal combustion engine is configured to drive the generator, and wherein the internal combustion engine is coupled to the generator by means of a mechanical interface. The range extender is characterized in that the interface has a flexplate or consists of the flexplate, wherein the flexplate is screwed to a crankshaft of the internal combustion engine and wherein the flexplate is screwed to a rotor or a rotor carrier of the generator.

[0006] The flexplate can therefore have a connecting section in the area of ​​an inner diameter for screwing the flexplate to the crankshaft, such as a bolt circle or the like.

[0007] The flexplate may have a connecting portion in an outer diameter region for bolting the flexplate to the rotor or rotor carrier of the generator, such as a bolt circle or the like. In other words, the flexplate may therefore form a large-diameter connecting flange for mechanically coupling the crankshaft to the rotor or rotor carrier of the generator.

[0008] As the name suggests, the flexplate can exhibit a certain degree of flexibility in the axial direction, meaning it can be reversibly deformed. This allows axial misalignments between the crankshaft and the rotor or rotor carrier of the generator to be compensated.

[0009] A thickness of the flexplate measured in the axial direction is in particular less than one tenth of the diameter of the flexplate, in particular less than one twentieth of the diameter of the flexplate.

[0010] The flexplate can be used for the direct mechanical connection of the crankshaft to the rotor or rotor carrier of the generator, with the flexplate in particular being in direct contact with the crankshaft and the rotor or rotor carrier of the generator. This eliminates the need for gearboxes arranged between the combustion engine and the generator or additionally enclosed connection modules. In this way, the invention enables a compact, cost-effective design of the range extender while simultaneously reliably coupling the combustion engine to the generator. In particular, no housings or housing walls are arranged between the generator and the combustion engine in the axial direction.

[0011] It is known to use a flexplate to connect an internal combustion engine to an associated automatic transmission. In vehicles with automatic transmissions, a flexplate is used, for example, to connect the crankshaft to the torque converter.

[0012] The English term “Flexplate” has become established as a technical term in German-speaking countries.

[0013] The flexplate is a metal disc or a thin-walled flange made of a metallic material.

[0014] The flexplate may have a starter ring gear. In this case, the flexplate may not have a starter ring gear.

[0015] It may be provided that the generator is designed to charge a traction battery of the electric motor-driven vehicle.

[0016] The internal combustion engine can have a housing with at least one through-opening, wherein the through-opening of the housing is arranged on the diameter of a bolt circle of the flexplate for screwing to the rotor or the rotor carrier, wherein the bolt circle of the flexplate can be aligned relative to the through-opening such that the through-opening of the housing is aligned with a through-opening of the bolt circle of the flexplate. The flexplate can thus be screwed to the rotor or the rotor carrier by inserting a respective screw and a tool for screwing through the through-opening of the housing. The through-opening of the housing therefore serves as an assembly opening for screwing the flexplate to the rotor or the rotor carrier. By rotating the crankshaft during assembly, all screw connections can be fitted one after the other, even if only one through-opening is present.

[0017] It can be provided that a rotor shaft of the generator is mounted by means of a bearing, in particular that the bearing is a fixed bearing, further in particular that the bearing is a rolling bearing.

[0018] One end of the rotor shaft can be provided to protrude into an opening in the crankshaft. This allows for a compact arrangement with a short axial length.

[0019] The fixed bearing ensures precise alignment of the stator and rotor. If, in alternative designs, this precise axial alignment of the stator and rotor can be guaranteed by the crankshaft and the flexplate, the rolling bearing can also be designed as a floating bearing.

[0020] According to one embodiment of the range extender, it can be provided that, in addition to the bearing, no additional rolling bearing is required to support the rotor shaft, in particular that a clearance fit is formed between the shaft end and the opening. This allows for a compact and cost-effective bearing arrangement for the rotor shaft.

[0021] Alternatively, it can be provided that in addition to the bearing, a further bearing is provided for supporting the rotor shaft, wherein the further bearing is in particular a loose bearing, further in particular a rolling bearing.

[0022] If a floating bearing and a fixed bearing are provided for supporting the rotor shaft, the rotor shaft end may not protrude into an opening in the crankshaft. In this case, the crankshaft may be designed without an opening at the front end.

[0023] The generator can be designed according to the principle of an axial flux motor.

[0024] The generator can be designed according to the principle of a radial flux motor. The rotor can be an external rotor, an internal rotor, or a double rotor.

[0025] As already discussed, it can be provided that no housing wall is provided between the flexplate and the rotor or rotor carrier.

[0026] It can be provided that an axial bearing of the crankshaft of the internal combustion engine is formed by the bearing of the generator.

[0027] The invention is described in more detail below with reference to drawings illustrating exemplary embodiments. Each of these drawings schematically shows: Fig. 1 shows a first range extender according to the invention in a sectional view; Fig. 2 shows a second range extender according to the invention in a sectional view; Fig. 3 shows a third range extender according to the invention in a sectional view; Fig. 4 shows a fourth range extender according to the invention in a sectional view; Fig. 5 shows a fifth range extender according to the invention in a sectional view; Fig. 6 shows a sixth range extender according to the invention in a sectional view; Fig. 7 shows a seventh range extender according to the invention in a sectional view; Fig. 8 shows an eighth range extender according to the invention in a sectional view.

[0028] Fig. Figure 1 shows a first range extender 2 according to the invention for an electric motor-driven vehicle. The range extender 2 has an internal combustion engine 4 and a generator 6.

[0029] The internal combustion engine 4 is configured to drive the generator 6. The generator 6 is configured to charge a traction battery of the electric motor-driven vehicle. The internal combustion engine 4 is coupled to the generator 6 via a mechanical interface 8.

[0030] The interface 8 is a flexplate 8 or consists of the flexplate 8, wherein the flexplate 8 is screwed to a crankshaft 10 of the combustion engine 4 and wherein the flexplate 8 is screwed to a rotor 12 of the generator 6. Another rotor 13 is connected to a rotor shaft 24 of the generator.

[0031] The flexplate 8 has a connecting section 14 in the area of ​​an inner diameter for screwing the flexplate 8 to the crankshaft 10, namely a bolt circle 14.

[0032] The flexplate 8 has, in the region of an outer diameter, a connecting section 16 for screwing the flexplate 8 to the rotor 12 of the generator 6, namely a bolt circle 16. The flexplate 8 therefore forms a connecting flange with a large diameter in order to mechanically couple the crankshaft 10 to the rotor 12 of the generator 6.

[0033] The rotor 12 is therefore screwed to the flexplate 8 in the area 18 of its outer diameter.

[0034] The flexplate 8 is used for the direct mechanical connection of the crankshaft 10 to the rotor 12. The flexplate 8 lies directly against the crankshaft 10 and the rotor 12 of the generator 6. No housing or housing walls are arranged between the generator 6 and the combustion engine 4, viewed in the axial direction.

[0035] The internal combustion engine 4 has a housing 20 with a through-opening 22. The screw connection of the flexplate 8 to the rotor 12 can be made starting from the engine side in the direction R. The through-opening 22 of the housing 20 therefore serves as an assembly opening for screwing the flexplate 8 to the rotor 12. The screw connection can be made with screws or with stud bolts and nuts.

[0036] The rotor shaft 24 of the generator 6 is preferably supported by a fixed bearing 26. The fixed bearing 26 is a roller bearing 26. A shaft end 28 of the rotor shaft 24 projects into an end-face axial opening 30 of the crankshaft 10.

[0037] In addition to the fixed bearing 26, no further rolling bearing is provided for supporting the rotor shaft 24. A clearance fit is preferably formed between the shaft end 28 and the opening 30.

[0038] The generator 6 is designed according to the principle of an axial flux motor. The rotors 12 and 13 enclose a stator 32 of the generator 6 on both sides. An inverter 34 and a sensor, e.g., a resolver 36, are assigned to the generator 6.

[0039] The following is based on reference to Fig. 2 describes a further embodiment of a range extender 2' according to the invention. To avoid repetition, only the differences from the previously described embodiment will be discussed, with the same reference numerals being assigned to the same features.

[0040] The Range Extender 2' according to Fig. 2 differs from the Range Extender 2 according to Fig. 1, that the Range Extender 2' according to Fig. 2, in addition to the fixed bearing 26, has a floating bearing 38 for supporting the rotor shaft 28. The floating bearing 38 is a rolling bearing. If two rolling bearings are used, an adjusted or floating bearing can also be used instead of a fixed-loose bearing arrangement.

[0041] The following is based on reference to Fig. 3 describes a further embodiment of a range extender 2" according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0042] The Range Extender 2'' according to Fig. 3 differs from the Range Extender 2 according to Fig. 1 and from the Range Extender 2' according to Fig. 2, that the Range Extender 2" according to Fig. 3 has a generator 6" designed according to the principle of a radial flux motor. The generator 6" has a rotor carrier 40 that supports the rotors 12 and 13, forming a double rotor. In addition to the fixed bearing 26, no further rolling bearing is provided for supporting the rotor shaft 24.

[0043] The following is based on reference to Fig. 4 describes a further embodiment of a range extender 2''' according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0044] The Range Extender 2''' according to Fig. 4 differs from the Range Extender 2'' according to Fig. 3, that the Range Extender 2''' according to Fig. 4, in addition to the fixed bearing 26, has the floating bearing 38 for supporting the rotor shaft 28. The floating bearing 38 is a rolling bearing.

[0045] The following is based on reference to Fig. 5 describes a further embodiment of a range extender 2'''' according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0046] The Range Extender 2'''' according to Fig. 5 differs from the Range Extender 2'' according to Fig. 3, the range extender 2"" has only one rotor 12 on the rotor carrier 40. The generator 6" is therefore designed in the manner of a radial flux motor with an external rotor. In addition to the fixed bearing 26, no further rolling bearing is provided for supporting the rotor shaft 24.

[0047] The following is based on reference to Fig. 6 describes a further embodiment of a range extender 2''''' according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0048] The Range Extender 2''''' according to Fig. 6 differs from the Range Extenders 2'''' according to Fig. 5, that the Range Extender 2''''' according to Fig. 6 has, in addition to the fixed bearing 26, the floating bearing 38 for supporting the rotor shaft 28. The floating bearing 38 is a rolling bearing.

[0049] The following is based on reference to Fig. 7 describes a further embodiment of a range extender 2'''''' according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0050] The Range Extender 2'''''' according to Fig. 7 differs from the Range Extenders 2'''' according to Fig. 5, that the generator 6'' of the range extender 2'''''' according to Fig. 7 is designed in the manner of a radial flux motor with an internal rotor. In addition to the fixed bearing 26, no further rolling bearing is provided for supporting the rotor shaft 24.

[0051] The following is based on reference to Fig. 8 describes a further embodiment of a range extender 2''''''' according to the invention. To avoid repetition, only the differences from a previously described embodiment will be discussed, with the same features being assigned the same reference numerals.

[0052] The Range Extender 2'''''''' according to Fig. 8 differs from the Range Extenders 2'''''' according to Fig.7, that the generator 6'' of the range extender 2'''''''' has, in addition to the fixed bearing 26, the floating bearing 38 for supporting the rotor shaft 28. The floating bearing 38 is a rolling bearing.

Claims

[1] Range extender for an electric motor-driven vehicle, - with an internal combustion engine (4), - with a generator (6), - wherein the combustion engine (4) is arranged to drive the generator (6) and - wherein the combustion engine (4) is coupled to the generator (6) by means of a mechanical interface, characterized by , that - the interface has a flexplate (8) or consists of the flexplate (8), wherein the flexplate (8) is screwed to a crankshaft (10) of the internal combustion engine (4) and - wherein the flexplate (8) is screwed to a rotor (12) or a rotor carrier (40) of the generator (6). [2] Range extender according to claim 1, characterized bythat the internal combustion engine (4) has a housing (20) with at least one through-opening (22), wherein the through-opening (22) of the housing (20) is arranged on the diameter of a hole circle (16) of the flexplate (8) for screwing to the rotor (12) or the rotor carrier (40), wherein the hole circle (16) of the flexplate (8) is alignable relative to the through-opening (22) such that the through-opening (22) of the housing (20) is aligned with a through-opening of the hole circle (16) of the flexplate (8). [3] Range extender according to one of the preceding claims, characterized by that a rotor shaft (24) of the generator (6) is mounted by means of a bearing (26), in particular that the bearing (26) is a fixed bearing, further in particular that the bearing is a rolling bearing (26). [4] Range extender according to one of the preceding claims, characterized bywherein a shaft end (28) of the rotor shaft (24) projects into an opening (30) of the crankshaft (10). [5] Range extender according to claim 3 or claim 4, characterized by that in addition to the bearing (26) no further rolling bearing is provided for supporting the rotor shaft (24), in particular that a clearance fit is formed between the shaft end (28) and the opening (30). [6] Range extender according to one of the preceding claims 1-4, characterized by that in addition to the bearing (26) a further bearing (38) is provided for supporting the rotor shaft (24), wherein the further bearing (38) is a rolling bearing. [7] Range extender according to one of the preceding claims, characterized by that the generator (6) is designed according to the principle of an axial flux motor. [8] Range extender according to one of the preceding claims, characterized bythat the generator (6) is designed according to the principle of a radial flux motor, wherein the rotor (12, 13) is designed as an external rotor, as an internal rotor or as a double rotor. [9] Range extender according to one of the preceding claims, characterized by that there is no housing wall between the flexplate (8) and the rotor (12) or rotor carrier (40). [10] Range extender according to one of the preceding claims, characterized by that an axial bearing of the crankshaft of the internal combustion engine is formed by the bearing of the generator.

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