Bicycle drive unit, method for manufacturing a bicycle drive unit and bicycle

Abstract

A bicycle drive unit (100) for use in an electrically assisted bicycle comprises a housing (10), a crankshaft (300) rotatably mounted about a crankshaft axis of rotation and positioned to extend through the housing (10), and an electric motor (200) arranged within the housing (10) and comprising a stator (210) and a rotor (220) rotatably mounted about a rotor axis of rotation, the stator (210) having a stator winding. The rotor (220) has a drive gear (223), and the crankshaft (300) has an output gear (301). A transmission (800) comprises at least one transmission gear (801), the transmission (800) being arranged between the drive gear (223) and the output gear (301). A power converter (700) has a first circuit carrier (701) and at least one circuit component (702) arranged on the first circuit carrier (701).A terminal plate (400) has a second circuit carrier (404), wherein the second circuit carrier (404) has at least one conductor for connecting the stator winding to the converter (700). An angle position sensor (600) for measuring an angular position of the rotor (220) has a third circuit carrier (602) and at least one magnetic field sensor (601) arranged on the third circuit carrier (602). A motor cover (500), to which the angle position sensor (600) is attached, is arranged between the electric motor (200) and the gearbox (800), wherein the angle position sensor (600) is arranged between the motor cover (500) and the electric motor (200).

Description

[0001] The present invention relates to a bicycle drive unit, a bicycle and a method for manufacturing a bicycle drive unit. Background of the invention

[0002] Electric bicycles with motor assistance are also known as pedelecs. A typical design includes a mid-drive motor, which is located on the bicycle frame in the area of ​​the crankshaft and comprises not only the electric motor but also a gearbox and the crankshaft, all housed in a single casing.

[0003] DE 10 2020 134 353 A1 relates to a drive unit for a human-powered vehicle comprising a housing that supports an input shaft into which human propulsion force is applied, a motor that is provided and configured on the housing to exert a propulsive force on the human-powered vehicle, and an electronic circuit board provided in the housing. The electronic circuit board includes at least one first electronic component that forms at least part of an inverter circuit configured to supply the motor with electrical energy, a first circuit board on which the at least one first electronic component is provided, a controller that includes at least one second electronic component, and a second circuit board on which the at least one second electronic component of the controller is provided.The controller is electrically connected to the inverter circuit and configured to control it. The second circuit board is designed separately from the first. Disclosure of the invention

[0004] According to the invention, an electric bicycle drive unit, a bicycle with such a bicycle drive unit, and a method for manufacturing such a bicycle drive unit with the features of the independent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

[0005] The invention presents an electric bicycle drive unit in the form of a mid-drive motor, which is compact and easy to assemble. This is achieved through a modularization of the electrical components and the use of three pre-assembled circuit carrier units arranged in a specific manner within the housing.

[0006] Specifically, the bicycle drive unit for use in an electrically assisted bicycle comprises a housing, a crankshaft rotatably mounted about a crankshaft axis of rotation and positioned so that it extends through the housing, and an electric motor arranged within the housing, comprising a stator and a rotor rotatably mounted about a rotor axis of rotation. The stator has a stator winding. The stator winding, in particular, has several phase windings, e.g., three phase windings, often designated U, V, and W.

[0007] The rotor has a drive gear, and the crankshaft has an output gear, and a transmission comprising at least one gear is arranged between the drive gear and the output gear. The rotor is non-rotatably connected to the drive gear; the crankshaft can be non-rotatably connected to the output gear or via a freewheel.

[0008] The bicycle drive unit includes a power converter (also called an inverter) for supplying current to the stator winding. The power converter comprises a first circuit carrier and at least one circuit component arranged on the first circuit carrier. The at least one circuit component can be, for example, a semiconductor switch such as a MOSFET or IGBT, or a half-bridge chip with multiple semiconductor switches. This component ultimately serves to apply a desired voltage to the stator winding.

[0009] The bicycle drive unit further comprises a terminal plate with a second circuit carrier, the second circuit carrier having at least one conductor for connecting the stator winding to the converter. The terminal plate thus serves to establish the electrical connection between the converter and the stator winding. In particular, the terminal plate has at least one phase terminal for connecting the stator winding, or one phase terminal for connecting each phase winding.

[0010] The bicycle drive unit further comprises an angle position sensor for measuring the angular position of the rotor, wherein the angle position sensor includes a third circuit carrier and at least one magnetic field sensor arranged on the third circuit carrier. For example, the at least one magnetic field sensor can be a Hall sensor, GMR sensor, TMR sensor, etc. For example, the at least one magnetic field sensor can serve to detect a magnetic field emanating from the rotor and, depending on the magnetic field, to determine the angular position of the rotor or to enable such a determination by a processing unit. The processing unit can, in particular, be part of the inverter and / or be arranged on the first circuit carrier. The inverter is specifically configured to energize the stator winding depending on the angular position of the rotor in order to generate a torque that can be used to propel the bicycle.

[0011] The angle position sensor is attached to a motor cover located between the electric motor and the gearbox. In other words, the angle position sensor is located on the side of the motor cover facing the electric motor. Specifically, the motor cover thus creates a physical separation between the electric motor and the gearbox and, if the motor cover is attached to the housing (e.g., with screws), can also serve to secure the electric motor, along with the connection plate and the angle position sensor, within the housing.

[0012] In one embodiment, the power converter has at least one first connector component, the connection plate has at least one second connector component, and the at least one first connector component is designed for detachable mating with the at least one second connector component to form an electrical contact. This simplifies the assembly of the bicycle drive unit, as no permanent connection, for example by welding or soldering, is required.

[0013] Compared to conventional electrical connections, welding between the terminal plate or its conductor tracks / busbars and the phase outputs of the converter is eliminated. This allows for greater design freedom, meaning that access for welding equipment or similar is not required. Assembly is also significantly simplified, as the converter simply needs to be plugged onto the stator or terminal plate. For a (better) mechanical connection between the converter and stator, additional connecting elements, such as screws, can be provided; however, a suitably (mechanically stable and secure) design of the plug connections is also conceivable.

[0014] In particular, at least one second connector component of the terminal plate is electrically connected to at least one conductor track of the terminal plate, and thus further, in particular, to at least one phase terminal of the terminal plate. The corresponding phase outputs of the phase windings and phase terminals of the terminal plate can be welded or crimped in a conventional manner, etc. The terminal plate can be connected to the stator, in particular, at an early stage of manufacturing.

[0015] In one embodiment, the at least one first connector component and the at least one second connector component are aligned with their insertion direction in the axial direction of the electric motor, i.e., parallel to a rotor axis of rotation of the electric motor. This means, in particular, that any relative movement of the terminal plate and the power converter when plugged together occurs parallel to this axial direction. This allows the terminal plate and the power converter to be connected simultaneously via all connectors.

[0016] The proposed connector can have separate connector components for each phase, each with one plug pin, or a combined or common connector component with multiple plug pins for several or all phases.

[0017] This type of phase connection eliminates any design limitations imposed by assembly tools on the power converter (clearance for welding electrodes from radial or axial directions). The resulting space can be used to design the power converter with regard to size reduction, increased cooling capacity (greater design space for cooling fins or cooling tubes), and improved (more efficient) electrical layout. There is no longer any dependence on the phase arrangement or assembly processes. The assembly process between the electric machine and the power converter is reduced to the steps of placing and, if necessary, separately bolting the power converter to the stator.

[0018] In one embodiment, a male connector component selected from the at least one first connector component and the at least one second connector component has a round plug pin with a diameter of at least 1 mm and / or at most 6 mm, and a female connector component selected from the at least one first connector component and the at least one second connector component has a round opening with a diameter matching the plug pin.

[0019] The connector pin is designed to fit into the round opening with the appropriate diameter. Connector systems with such diameters are widespread, for example as banana plugs or so-called XT connectors.

[0020] The connector uses plug pins or contact pins and corresponding openings, e.g., sockets, as mating parts (male and female) for the two corresponding connector components on the terminal block and the power converter. The plugs or contact pins can be used for the terminal block-side connector components and the openings for the power converter-side connector components, or vice versa.

[0021] According to one embodiment, the plug pin has a diameter of at most 2 mm or a nominal diameter of 2 mm. For example, the nominal diameter of banana plugs refers to the opening size; that is, the plug diameter is actually slightly smaller to fit into the opening. Such plug pins are small and handy, yet exhibit sufficient axial play tolerance and current-carrying capacity, particularly for bicycle drive units.

[0022] According to one embodiment, the male connector component, which includes the plug pin, is designed to carry currents of up to 100 A. This allows the male connector component to be kept small and manageable. Such currents are common, for example, in small drive units, such as those found in bicycles. The invention therefore offers particular advantages when used as a bicycle drive unit. Electric bicycles with motor assistance are also known as pedelecs. A typical design includes a mid-drive motor, which is arranged on the bicycle frame in the area of ​​the crankshaft and, in addition to an electric motor as described here, also includes a gearbox and the crankshaft, which are arranged in a housing.

[0023] According to one embodiment, the male connector component containing the plug pin has or is designed as a banana plug, for example, according to the 2 mm, 4 mm, or 6 mm plug system. A banana plug is a round plug pin with a contact spring (spring-loaded or lamellar plug) for laboratory, measuring instruments, and experiments. It is part of a low-voltage connector system and typically fits into a rigid socket (banana socket, telephone socket) of a suitable diameter (2, 4, or 6 mm). The plug is held securely by its spring but can be easily disconnected without tools. The current rating is up to approximately 10 amperes for 2 mm, up to approximately 32 amperes for 4 mm, and up to approximately 80 amperes for 6 mm. This provides a cost-effective solution and simplifies connection because no tools are required for assembly.The spring element in the banana plug can adapt to the axial play within the connection and ensures a flawless electrical connection.

[0024] According to one embodiment, the male connector component containing the plug pin has or is designed as an XT connector, for example, according to the XT30, XT60, or XT90 connector system. The XT30 connector system is equipped with 2 mm plugs and sockets and can handle a current of 25 A, and up to 35 A for short periods. The XT60 connector system is equipped with 3.5 mm plugs and is suitable for all applications up to 60 A continuous current or up to 100 A pulse. The XT90 connector system is equipped with 4.5 mm plugs and is suitable for all applications up to approximately 90 A continuous current or 120 A pulse.

[0025] According to one embodiment, the female connector component having the opening, in particular the power converter-side connector component, has or is designed as a banana jack, for example according to the 2 mm plug system or 4 mm plug system or the 6 mm plug system.

[0026] According to one embodiment, the female connector component having the opening, in particular the power converter-side connector component, has an XT socket, for example according to the XT30, XT60 or XT90 connector system, or is designed as such.

[0027] According to one embodiment, the female connector component with the opening, in particular the power converter-side connector component, has a metallized hole in a circuit carrier, such as a printed circuit board (PCB), with a diameter matching the connector pin, or is designed as such. In this embodiment, sockets can be eliminated and the plugs pass through the hole.

[0028] According to one embodiment, the female connector component with the opening, in particular the power converter-side connector component, has or is designed as an uninsulated metal sleeve with a diameter matching the plug pin. In this embodiment, sockets can be omitted and only simple metal sleeves are used instead.

[0029] The bicycle according to the invention has an embodiment of the bicycle drive unit which is attached to a bicycle frame.

[0030] The method for manufacturing the bicycle drive unit includes arranging the stator in the housing, arranging the terminal plate in the housing, connecting the stator winding to the terminal plate, and arranging the rotor in the housing.

[0031] These steps can be performed in a suitable sequence, for example, by first attaching the terminal plate to the stator and then placing the stator and terminal plate together in the housing, or by first placing the stator in the housing and then placing the terminal plate on top of the stator inside the housing. Connecting the stator's phase windings to the terminal plate's phase connections can also take place before or after placement in the housing.

[0032] Before the stator is placed in the housing, the housing can be heated to fix the stator in place by shrinking the housing. Specifically, the stator has a surrounding stator core with internal stator teeth, e.g., made of iron laminations, and phase windings wound around the stator teeth.

[0033] The motor cover, to which the angle position sensor is attached, is then positioned in the housing and, in particular, also attached to the housing, e.g. by screw connections.

[0034] The power converter is then placed in the housing and connected to the terminal plate, in particular by means of the plug connection described above.

[0035] Regarding the preferred designs and advantages of the method and the bicycle, reference is made to all explanations concerning the electric bicycle drive unit, which apply accordingly here, in order to avoid repetition.

[0036] In one embodiment, the method further comprises arranging the crankshaft in the housing, arranging the transmission in the housing, and optionally arranging other components, such as a torque sensor and / or torsion sensor, in the housing. These steps are performed after the motor cover has been installed. The power converter can be installed before, together with, between, or after these steps.

[0037] In one embodiment, the method further includes closing the housing. In particular, a second housing part, such as a housing cover, can be placed on a first housing part, such as a housing pot, and fastened there, especially by screwing. All steps previously described that relate to an arrangement "in the housing" can accordingly mean an arrangement "in the first housing part".

[0038] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0039] The invention is schematically illustrated in the drawing using exemplary embodiments and is described below with reference to the drawing. Brief description of the drawings Fig. Figure 1 shows a first housing part of a housing of a bicycle drive unit, in one embodiment. Fig. Figure 2 shows the first housing part with a stator and a connection plate, in one embodiment. Fig. Figure 3 shows the first housing part with the stator, the connection plate and a rotor, in one embodiment. Fig. Figure 4 shows an engine cover with an angle position sensor mounted on it, in one embodiment. Fig. 5 shows the first housing part made of Fig. 3 with the engine cover from Fig. 4, in one embodiment. Fig. 6 shows the first housing part made of Fig. 5 with a crankshaft, a gearbox and a power converter. Fig. Figure 7 shows the bicycle drive unit with the housing having the first housing part made of Fig. 6 and a second housing part. Fig. Figure 8 shows an embodiment of a bicycle with a bicycle drive unit. Detailed description

[0040] In the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. Figure 7 shows various stages or steps of assembling a bicycle drive unit 100. Such a bicycle drive unit 100 can be used as drive assistance in a bicycle 1000, as shown in Fig. Figure 8 shows the bicycle drive unit 100 being attached to a bicycle frame 1100 of the bicycle 1000.

[0041] First, a first housing part 11 of a housing 10 of the bicycle drive unit 100 is assembled, as shown in Fig. 1 shown, provided. The first housing part 11 can in particular have fastening points 15 for attaching the bicycle drive unit to the bicycle frame 1100 of the bicycle 1000, locking points 16 for receiving, for example, screws for fixing a second housing part 12 (cf. Fig. 7) of the housing 10, a housing feedthrough 17a in particular for routing control and / or power supply lines, a first housing section 18 for accommodating an electric motor 200 (see Fig. 3) and a second housing section 19 for receiving a crankshaft 300 (see Fig. 6) exhibit.

[0042] In Fig. Figure 2 shows that a stator 210 of the electric motor 200 is arranged or received in the first housing section 18, wherein the electric motor 200 is designed as an internal rotor motor and has a series of stator teeth 211 that point towards a central rotor axis of rotation A of the electric motor, which in the figures runs parallel to a z-direction. An x-direction corresponds to the direction of gravity when the bicycle 1000 is horizontally oriented, and a y-direction is opposite to the direction of travel.

[0043] The stator 210 of the electric motor 200 can be inserted into the heated first housing part 11, whereupon the first housing part 11 is shrunk onto the stator 210. Additionally, the stator 210 can be fixed and aligned relative to the first housing part 11 by means of alignment means 20, each designed as a groove, in which, for example, bolts or pins can be arranged.

[0044] A connection plate 400 is arranged on the stator 210, which is used to connect phase windings of the stator 210 to the power converter 700 (see figure). Fig. 6) serves. The phase windings can be wound in a coil-like fashion around the stator teeth 211. An electrical connection between the phase windings and conductor tracks (not shown) running in or on a first circuit carrier 404 of the terminal plate 400 can be established via phase terminals 403. The phase windings can be welded to the phase terminals 403. A connection between the terminal plate 400 and the power converter 700 can be established via connector components, here in the form of banana plugs 401.

[0045] In the illustrated embodiment, the three banana plugs 401 each form a male connector component, which has a round pin with, for example, a nominal diameter of 2 mm (the actual diameter is smaller so that the plug fits into the socket). It can also be seen that a 2 mm banana plug has a spring collar with four contact springs. This allows for very simple compensation of tolerances in the radial direction.

[0046] Each connector component 401 is designed to be detachably plugged together with a corresponding mating connector component (not shown) on the power converter 700 to form an electrical contact between the terminal plate 400 and the power converter 700.

[0047] The terminal block 400 has twelve phase terminals 403 for connecting twelve coils of the phase windings. Specifically, four of the coils are assigned to each phase winding (which can be designated, for example, as U, V, or W) and connected via their respective phase terminal to one of the three banana plugs 401.

[0048] In Fig. Figure 3 shows that a rotor 220 of the electric motor 200 is inserted into the stator 210. The rotor 220 has a rotor core 221 with recesses in which permanent magnets 222, in this case arranged in a spoke arrangement, are located. The rotor also has a drive gear 223.

[0049] In Fig. Figure 4 shows a motor cover 500 on which an angle position sensor 600 is arranged or attached on the side of the motor cover 500 facing the electric motor 200. Specifically, the angle position sensor 600 is arranged between the electric motor 200 and the motor cover 500, such that the motor cover 500 encloses the assembly comprising the electric motor 200, the terminal plate 400, and the angle position sensor 600 within the housing section 18. In the example shown, the angle position sensor 600 has three magnetic sensors 601, which are arranged, for example, soldered onto a third circuit carrier 602 and serve to detect a magnetic field of the rotor 220, which can be used to determine the angular position of the rotor 220. In the example shown, the magnetic sensors 601 are arranged on the side of the third circuit carrier 602 facing the electric motor 200.

[0050] In Fig. Figure 5 shows that the motor cover 500 is arranged in the first housing part 11 such that it covers the electric motor 200, the connection plate 400 and the angle position sensor 600 and is structurally separated from an additional gearbox 800 to be arranged in the first housing part 11 (see Figure 5). Fig. 6) and the crankshaft 300. In particular, the engine cover 500 has fastening openings 501 with which it can be attached, in particular screwed, to the first housing part 11 of the housing 10.

[0051] It can be seen that the connector components 401 protrude through the motor cover 500.

[0052] In Fig. Figure 6 shows that the crankshaft 300 is inserted in the second housing section 19 and is connected to the drive gear 223 via the transmission 800. An output gear 301 is attached to the crankshaft 300, which meshes with a first gear of the transmission 800 (not shown). The first gear is fixed to a common transmission shaft in a rotationally fixed manner with a second gear 801, the second gear 801 meshing with the drive gear 223.

[0053] Furthermore, in Fig. 6. The power converter 700, which has a second circuit carrier 701 with circuit components 702 arranged on it, is mounted on the motor cover 500. In particular, the power converter 700 also has mating connectors, for example in the form of banana jacks, which are plugged into the connectors 401 to form an electrical contact. The circuit components 702 serve to implement the function of the power converter and include, for example, microcontrollers, semiconductor switches, capacitors, gate drivers, etc. At least the semiconductor switches are electrically connected to the banana jacks to energize the phase windings of the stator 210 in the desired manner.

[0054] It can be seen that the connector components are aligned with their insertion direction in the axial direction A of the electric motor 200, which facilitates the assembly of the bicycle drive unit and saves tools.

[0055] In Fig. Figure 7 shows the bicycle drive unit 100, with the first housing part 11 closed with a second housing part 12 to form the housing 10. The mounting points 15, the crankshaft 300, and the housing feedthrough 17a are also visible. A second housing feedthrough 17b serves to supply the electric motor 200 or the bicycle drive unit 100 with electrical energy, in this example with a DC voltage. Reference symbol list 10 cases 11 first housing part 12 second housing part 15 Mounting point 16 Locking point 17a Housing feedthrough 17b second housing feedthrough 18 first housing section 19 second housing section 20 alignment tools 100 bicycle drive units 200 electric motor 210 Stator 211 Stator tooth 220 Rotor 221 Rotor core 222 Permanent magnet 223 Drive gear 300 crankshaft 400 connection plate 401 banana plugs 403 Phase connection 404 first circuit carrier 500 engine covers 501 Mounting opening 600 angle position sensor 601 Magnetic sensor 602 third circuit carrier 700 power converters 701 second circuit carrier 702 circuit components 800 gearbox 801 Gear wheel 1000 bicycles 1100 bicycle frames

Claims

Bicycle drive unit (100) for use in an electrically assisted bicycle (200), comprising: - a housing (10), - a crankshaft (300) rotatably mounted about a crankshaft axis of rotation and positioned so that it extends through the housing (10), - an electric motor (200) arranged within the housing (10) and comprising a stator (210) and a rotor (220) rotatably mounted about a rotor axis of rotation, - wherein the stator (210) has a stator winding, - wherein the rotor (220) has a drive gear (223), and the crankshaft (300) has an output gear (301), - a transmission (800) comprising at least one transmission gear (801), wherein the transmission (800) is arranged between the drive gear (223) and the output gear (301), - a converter (700) comprising a first circuit carrier (701) and at least one circuit component (702) arranged on the first circuit carrier (701),- a connection plate (400) comprising a second circuit carrier (404), wherein the second circuit carrier (404) has at least one conductor for connecting the stator winding to the converter (700), - an angle position sensor (600) for measuring an angular position of the rotor (220), the angle position sensor (600) comprising a third circuit carrier (602) and at least one magnetic field sensor (601) arranged on the third circuit carrier (602), - a motor cover (500) to which the angle position sensor (600) is attached, - wherein the motor cover (500) is arranged between the electric motor (200) and the gearbox (800), and - wherein the angle position sensor (600) is arranged between the motor cover (500) and the electric motor (200). Bicycle drive unit (100) according to claim 1, wherein the power converter (700) has at least one first connector component, wherein the connection plate (400) has at least one second connector component (401), wherein the at least one first connector component is designed for detachable connection with the at least one second connector component (401, 401) to form an electrical contact. Bicycle drive unit (100) according to claim 2, wherein the at least one first connector component and the at least one second connector component (401, 401) are aligned with their plugging direction in the axial direction (A) of the electric motor (200). Bicycle drive unit (100) according to claim 2 or 3, wherein a male connector component selected from the at least one first connector component and the at least one second connector component (401, 401) has a round plug pin with a diameter of at least 1 mm and / or at most 2 mm or at most 6 mm, wherein a female connector component selected from the at least one first connector component and the at least one second connector component (401, 401) has a round opening with a diameter matching the plug pin. Bicycle drive unit (100) according to claim 4, wherein the male connector component having the plug pin has a banana plug (401) and / or an XT plug (402). Bicycle drive unit (100) according to claim 4 or 5, wherein the female connector component having the opening comprises a banana jack and / or an XT jack and / or a metallized hole in the first or second circuit carrier with a diameter matching the plug pin and / or an uninsulated metal sleeve with a diameter matching the plug pin. Bicycle (1000) with a bicycle drive unit (100) according to one of the preceding claims, which is attached to a bicycle frame (1100) of the bicycle (1000). Method for manufacturing a bicycle drive unit (100) according to one of the preceding claims, comprising: - arranging the stator (210) in the housing (10), - arranging the terminal plate (400) in the housing (10), - connecting the stator winding to the terminal plate (400), - arranging the rotor (220) in the housing (10), - subsequently arranging the motor cover (500), to which the angle position sensor (600) is attached, in the housing (10), - subsequently arranging the power converter (700) in the housing (10) and connecting the power converter (700) to the terminal plate (400). The method of claim 8, wherein the arrangement of the stator (210) and the arrangement of the terminal plate (400) in the housing (10) comprises: - first arranging the terminal plate (400) on the stator (210) and then arranging the stator (210) together with the terminal plate (400) in the housing (10), or - first arranging the stator (210) in the housing (10) and then arranging the terminal plate (400) in the housing (10). Method according to claim 8 or 9, further comprising: - arranging the crankshaft (300) in the housing (10), - arranging the transmission (800) in the housing (10).

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