Motor assembly for a bicycle

Abstract

The invention relates to a motor assembly (1) for a bicycle, wherein the motor assembly (1) has a housing (10), an electric motor (12), a printed circuit board (26) and a temperature sensor (32). The electric motor (12) is positioned in the housing (10) and has a motor winding (18), and the printed circuit board (26) is positioned outside the housing (10) and has a plug (28). The printed circuit board (26) is electrically connected, by means of the plug, to the electric motor (12) in order to control same, and the temperature sensor (32) is designed to detect a temperature value of the motor winding (18) and is provided on the plug (28). The invention also relates to another motor assembly (1) and to a bicycle.

Description

[0001] Motor arrangement for a bicycle

[0002] Technical area

[0003] The present invention relates to a motor assembly for a bicycle that enables temperature detection of a motor winding. Furthermore, the present invention relates to a bicycle having such a motor assembly.

[0004] State of the art

[0005] For electric motors in bicycles, such as pedelecs, it is desirable to know the temperature of the motor windings. This can prevent overheating and thus damage to the drive motor. Furthermore, with a precisely known temperature in the drive motor windings, higher drive power can be provided for a short time. For example, a smaller drive motor can be used, or a bicycle can have a higher assist power.

[0006] However, directly measuring the winding temperature in the drive motor is expensive and complex. Leading the respective sensor cables out of the drive motor can also compromise the seal, which is particularly undesirable on bicycles due to their high exposure to dirt and moisture. Furthermore, such a cable can quickly be damaged by vibration and deformation.

[0007] US 2012 / 313462 A1 describes an electric motor with a molded encapsulation made of a plastic material with a defined thermal conductivity and a temperature sensor arranged thereon. The application also discloses control electronics designed to calculate a temperature in the area of ​​stator windings based on the temperature detected by the temperature sensor. The temperature sensor is arranged in a recess formed by a protruding wall of the encapsulation of the electric motor. This can quickly damage a connection between the sensor and other electronic components, for example, due to vibrations or thermal deformation of the encapsulation. Furthermore, mounting the temperature sensor in the recess is difficult.

[0008] Description of the invention

[0009] The object of the present invention is to enable improved temperature measurement of motor windings in electric bicycle motors. This object is achieved by the independent patent claims.

[0010] A first aspect relates to a motor assembly for a bicycle. The bicycle can be designed, for example, as a mountain bike, touring bike, or racing bike. The bicycle has an electric motor. The bicycle can be designed, for example, as a pedelec.

[0011] The motor assembly comprises a housing, an electric motor, a circuit board, and a temperature sensor. The motor assembly may be an assembly that is, for example, pre-assembled and installed in the bicycle. The electric motor may be a drive motor of the bicycle. The electric motor may, for example, drive a wheel of the bicycle and assist a cyclist in driving the bicycle. The electric motor is arranged in the housing and has a motor winding. By energizing the motor winding, the electric motor may, for example, provide drive power to a motor shaft. This may cause the motor winding to heat up. The electric motor may comprise a rotor and a stator, wherein the rotor is configured to rotate relative to the stator. The stator may be rotationally fixed to the housing, and the rotor may form the motor shaft, or it may be permanently rotationally fixed to the motor shaft.The motor shaft can be designed to transmit torque through the housing. A part of the housing, such as a cover element, can form a bearing plate of the electric motor. For example, the motor shaft can be rotatably supported on the bearing plate and, alternatively or additionally, the bearing plate can hold at least one bearing for the motor shaft on the housing. The motor winding can be designed to bring about a rotary movement of the rotor in order to thus provide torque. The motor winding can have several individual windings. The motor winding can comprise a metal, for example a conductor such as copper. The housing can completely or partially enclose the electric motor. The housing can be an integral part of a frame of the bicycle or can also be formed separately therefrom. The housing can, for example, be made of metal and, alternatively or additionally, of plastic.The housing can be or have a cast component.

[0012] The circuit board is located outside the housing. The circuit board is electrically connected to the electric motor for its control. In the first aspect, the circuit board has a connector for this purpose. The motor winding can be connected to the circuit board, for example, via a cable that is plugged or soldered into the connector. A plug connection between the circuit board and the motor winding can be detachable.

[0013] The circuit board can be designed as a printed circuit board and can have electronic elements such as resistors, capacitors or microchips. The circuit board can be designed as a PCB. It can be designed as part of an inverter or other control device for the electric motor. The circuit board can provide a power supply for the electric motor for its operation. For example, a current for providing a driving force is transmitted to the motor winding via the circuit board, for example its connector. The circuit board can be arranged on the housing or the bicycle frame. The circuit board can be arranged at a distance from the housing. The circuit board can be covered by a cover, which can be arranged on the housing. For example, the circuit board can be arranged on the housing and covered by the cover.The cover and the housing may form an interior space which is separate from an interior space for the motor winding and in which the circuit board is arranged.

[0014] The plug can be designed to transmit an electrical current, for example to supply the motor winding with electrical current. The circuit board can have a power supply for the electric motor or provide a power supply for the electric motor. The electrical current for operating the electric motor can, for example, have a voltage between 5 V and 300 V. The current can also, for example, have a voltage between 10 V and 100 V. The electrical current for operating the electric motor can, for example, also have a voltage of approximately 48 V, for example a voltage between 47 V and 49 V. The temperature sensor can, for example, be operated with a voltage between 1 V and 10 V. For example, the temperature sensor can be operated with a voltage of approximately 3.3 V or with a voltage of approximately 5 V. The plug can be designed to transmit data or signals.The connector can, for example, transmit control signals from the circuit board to the electric motor and, in addition or alternatively, signals from the electric motor to the circuit board. For example, the connector can be in contact with another electrical component on the circuit board. The connector can be a female connector. The connector can also be a male connector. The connector can provide a detachable connection or a non-detachable connection. For example, the connector can be covered with epoxy resin and thus can no longer be separated from the motor winding.

[0015] The temperature sensor is designed to detect a temperature value of the motor winding. In the first aspect, the temperature sensor is arranged on the plug. The temperature sensor can be a sensor designed to detect a temperature. For example, an electrical conductivity of the temperature sensor can change depending on the temperature, or an electrical current can be induced in the temperature sensor depending on a temperature. The temperature value of the motor winding can be a value that is related to a motor winding temperature and, alternatively or additionally, to a temperature of the motor winding. For example, the temperature value can correspond to a motor winding temperature, wherein the motor winding temperature can generally be a value relevant to damage to the electric motor. The motor winding temperature can, for example, be a temperature inside the motor winding.For example, the insulation of a motor winding can permanently degrade if a maximum temperature is exceeded. The temperature value can also approximately correspond to the motor winding temperature, for example, due to cooling between the motor winding and the temperature sensor or connector, or a time delay in heat transfer. The temperature value can deviate from the motor winding temperature by a constant or variable amount. The motor winding temperature can be estimated or calculated from the temperature value. The motor winding temperature can be a temperature of the rotor, the stator, and alternatively or additionally the motor winding. The motor winding temperature can be an average temperature of the motor winding.

[0016] In the first aspect, the temperature sensor is arranged on the plug. The temperature sensor can be arranged on the plug or directly next to the plug. The temperature sensor can be in direct contact with the plug. For example, the temperature sensor can be in contact with the plug via a thermal paste. The plug is the area or component of the motor arrangement which assumes a temperature of the winding particularly precisely with a particularly short delay. For example, the plug is connected to the motor winding for power supply via a copper wire with a large cross-section. Heating of the motor winding is quickly transferred to the plug via this copper wire. The housing, on the other hand, can be more thermally insulating. For example, a gray cast iron housing can have a comparatively high thermal insulation effect compared to the copper wire.A thermal conductivity coefficient of an electrical connection of the plug to the motor winding may be greater than a thermal conductivity coefficient of the housing to the motor winding.

[0017] The described design and arrangement of the temperature sensor on the connector enable particularly simple and effective temperature measurement of the electric motor. The arrangement of the circuit board and the temperature sensor also enables a particularly simple design of the electric motor. By arranging the temperature sensor on the connector, the motor winding temperature can be measured particularly precisely, even if the temperature sensor is not located in the housing, for example. In addition, the temperature sensor can be easily connected to a controller for the electric motor and to the other components on the circuit board. The temperature sensor can be securely and easily mounted on the circuit board. Since the connection between the electric motor and the circuit board can have a high conductivity, the temperature at the connector can be particularly close to the temperature inside the motor.This allows the temperature of the engine to be determined without having to provide a temperature sensor inside the engine.

[0018] In one embodiment, the temperature sensor is connected to the connector using a thermally conductive adhesive. This allows the direct connection between the temperature sensor and the connector to ensure heat transfer for temperature measurement. However, the temperature sensor can also be connected to the connector using only a thermally conductive paste and attached in another way, for example to the circuit board. The thermally conductive adhesive can have a particularly high thermal conductivity. The thermally conductive adhesive can adhere the temperature sensor to the connector. Thermally conductive adhesive can provide a particularly thermally conductive connection between the connector and the temperature sensor. The thermally conductive adhesive can be a two-component adhesive. It can contain ceramic components. It can also contain metallic components, for example aluminum oxide. The thermally conductive adhesive can have a particularly high thermal conductivity coefficient compared to conventional adhesives.For example, EP30AN thermal adhesive from Masterbond can be used as a thermally conductive adhesive, and Arctic Alumina™ Thermal Adhesive from Arctic Silver Incorporated can be used additionally or alternatively. The temperature sensor can also be electrically connected to the circuit board, for example, the temperature sensor can be soldered to the circuit board's terminals. The temperature sensor can also be soldered to the connector.

[0019] The described connection of the temperature sensor to the connector achieves particularly good heat conduction between the temperature sensor and the connector. This enables particularly accurate detection of the motor winding temperature, as a particularly low thermal resistance can be achieved between the motor winding and the temperature sensor. By connecting the temperature sensor with a thermally conductive adhesive, additional fastening of the temperature sensor can be eliminated, thus enabling particularly simple installation.

[0020] In one embodiment, the temperature sensor is arranged on a side of the circuit board facing away from the housing. This allows the temperature sensor to be easily mounted and also requires little installation space. For example, other electrical components can also be arranged on a side of the circuit board facing away from the housing. The circuit board can be arranged at least partially parallel to a surface of the housing. The circuit board can, for example, be designed essentially as a flat component. Thus, the circuit board can have a flat side facing the housing and a flat side facing away from the housing. The connector can protrude through the circuit board, i.e. extend from a side facing the housing to a side facing away from the housing. A connection from the connector to the motor winding can also be routed laterally along the circuit board.The temperature sensor can be attached to the circuit board without interfering with the connection between the connector and the electric motor.

[0021] In one embodiment, the temperature sensor is arranged on a side of the circuit board facing the housing. Such a design can be advantageous if the connector is also arranged on the side of the circuit board facing the housing. This allows the connector to be easily connected to the motor winding. In addition, the temperature sensor can thus be protected from environmental influences by the circuit board. Furthermore, the temperature sensor can also be contacted with the housing, for example a protruding projection and alternatively or additionally thermal paste or thermal adhesive in order to additionally provide a thermal connection to the motor winding via the housing. For example, the other electrical components can be arranged on the side of the circuit board facing the housing, and assembly can then be simplified by arranging the temperature sensor there.

[0022] A second aspect also relates to a motor arrangement comprising a housing, an electric motor, a circuit board, and a temperature sensor. This motor arrangement can be designed substantially identically to the first aspect with the exception of the arrangement of the temperature sensor and the plug. Furthermore, the housing is adapted for a different arrangement. The electric motor is therefore also arranged in the housing and has a motor winding. The circuit board is arranged outside the housing and is electrically connected to the electric motor for its control. The connection can again be provided by the plug, as in the first aspect, or this plug can also be omitted. For example, the electrical connection to the motor winding can be soldered directly onto the circuit board.

[0023] The temperature sensor is also designed to detect a temperature value of the motor winding. In the second aspect, the temperature sensor rests on the housing. The temperature sensor can be electrically connected to the circuit board for transmitting the temperature value. The temperature sensor can be attached to the housing or, alternatively, to the circuit board. The housing has a projection projecting toward the circuit board, on which the temperature sensor rests. The temperature sensor can, for example, be arranged on a side of the circuit board facing the housing. The temperature sensor can, as previously described, also continue to be arranged on the connector.

[0024] A thermally conductive adhesive, a thermally conductive paste, or another conductor can be arranged between the housing and the temperature sensor.

[0025] The projection of the housing can be an integral part of the housing or present as a separate component attached thereto. The projection can be an integral part of a bearing plate of the housing or present as a separate component attached thereto. The projection can have a substantially cylindrical shape. Alternatively, the projection can also be substantially conical. The projection can have a dome shape. The projection can have a support surface for the temperature sensor, which is, for example, flat. The support surface can be created by post-processing. The support surface can, for example, be a flat surface parallel to the circuit board. For example, the support surface can be produced by milling or other processing methods. The thermally conductive adhesive or other conductors can be arranged on this surface in order to reduce thermal resistance to the temperature sensor.The housing can otherwise be designed as described for the first aspect.

[0026] Such an arrangement, in which the temperature sensor is in contact with a projection of the housing, can be advantageous because here too, heat transfer through the housing, alternatively or in addition to the plug, can enable a very precise inference with little delay about the temperature inside the motor winding. For example, the temperature sensor is arranged in the same radial area on the housing as the motor winding, so that the housing is heated here by the motor winding. By arranging it on the housing and not on the plug, additional electrical insulation between the plug and the temperature sensor or the electrical connection to the motor winding and the temperature sensor can be avoided. This may be necessary, for example, due to a high-voltage power supply to the motor winding to avoid malfunctions in the temperature sensor.In addition, such an arrangement can be particularly mechanically stable, as a projection extends close to the circuit board and the temperature sensor. This projection can provide additional support for the temperature sensor. In contrast to a recess, installation can also be simple. Furthermore, the temperature sensor can be positioned particularly flat against the circuit board, preventing the temperature sensor from breaking off due to impact during installation.

[0027] The temperature sensor can also be arranged on a projection of the housing in addition to the arrangement of another temperature sensor on the connector. This allows more temperature information to be acquired and enables a more precise determination of the motor winding temperature. Thus, two temperature sensors can be provided, with a first temperature sensor arranged on the projection of the housing and a second temperature sensor on the connector.

[0028] In one embodiment of the second aspect, the temperature sensor is connected to the housing projection by a thermally conductive adhesive. Alternatively or additionally, the temperature sensor is connected to the circuit board and, alternatively or additionally, to the connector by a thermally conductive adhesive. In one embodiment of the second aspect, the temperature sensor is arranged on a side of the circuit board facing the housing. The temperature sensor can, for example, be arranged on the circuit board opposite the connector. This allows additional heat to be transferred from the motor winding to the temperature sensor via the connector and the circuit board.

[0029] In one embodiment of the first and also the second aspect, the motor arrangement has an evaluation device which is designed to determine a current motor winding temperature depending on the temperature value. For this purpose, the evaluation device can be connected to the temperature sensor. This connection can be provided by the circuit board. The evaluation device can determine the temperature continuously or discontinuously using the temperature sensor. For example, the temperature sensor can detect the temperature at a sampling rate between 0.5 Hz and 10 Hz and, correspondingly, the current motor winding temperature can be determined at the same clock rate. The sampling rate and determination rate can also be between 1 Hz and 5 Hz, for example. The temperature value can be a temperature measured by the temperature sensor.The current motor winding temperature can be calculated, for example, from a constant or temperature-dependent deviation from the evaluation device. This can compensate for an offset in the measurement.

[0030] The deviation can be temperature-dependent, for example, proportional to the temperature value. This means that the deviation is smaller at a low temperature value than at a higher temperature value. The deviation can be determined using a mathematical model. Additionally or alternatively, the deviation can be determined using experimental measurements. The evaluation device can be designed to take a hysteresis of the deviation into account. The deviation can take a temperature profile into account. For example, the evaluation device can be designed to determine the current motor winding temperature depending on the profile of the temperature value. For example, a gradient of the temperature value can be taken into account for determining the current motor winding temperature.For example, if the motor winding heats up quickly, the deviation in the measured temperature can be large compared to if it heats up slowly, which can be compensated for by the evaluation device. Using the evaluation device and the determination of the current motor winding temperature, the actual temperature inside the motor winding can be calculated with great precision. This means that a motor controller based on the temperature value or the determined current motor winding temperature needs to take fewer tolerances in the motor winding temperature into account.

[0031] For example, this can mean that the calculated motor winding temperature remains higher than it would have been if the hysteresis had not been taken into account if the temperature value was previously high or above a limit value. In other words, the hysteresis can be taken into account by the evaluation device, for example by the deviation becoming larger when the temperature value becomes large. As a further example, a deviation can be larger with a large temperature value gradient than with a small temperature value gradient. As a further example, a deviation can be larger with a temperature value that increases over time than with a temperature value that decreases over time. Alternatively, a deviation can be smaller with a temperature value that increases over time than with a temperature value that decreases over time. The hysteresis can be determined using a mathematical model and additionally or alternatively using experimental measurements.The deviation can be negative, meaning the temperature value is lower than the current motor winding temperature. The deviation can also be positive, meaning the temperature value is higher than the current motor winding temperature. The deviation can also be positive, negative, or zero at different times.

[0032] In one embodiment, the evaluation device can be configured to determine the deviation as a function of a temporal gradient of the temperature value. The deviation can be proportional to a temporal gradient of the temperature value. Proportional to a temporal gradient means that a larger temporal gradient results in a larger temperature deviation. For example, the evaluation device can be configured to calculate a larger deviation for a rapidly rising temperature value than for a slowly rising temperature value. The current motor winding temperature can also be estimated by equating it with the temperature value.

[0033] The described embodiments allow a motor winding temperature to be determined particularly accurately, simply, and additionally or alternatively quickly. By taking into account the deviations between the temperature value and the motor winding temperature, the true motor winding temperature can be approximated. This allows the electric motor to be controlled particularly effectively and precisely. Additionally or alternatively, temperature-dependent safety factors can be designed to be particularly small without compromising safety, since the motor winding temperature can be determined more accurately.

[0034] In one embodiment, the evaluation device is arranged on the circuit board. The evaluation device can, for example, have one or more microchips arranged on the circuit board. The evaluation device can also have a memory module arranged on the circuit board. This allows the evaluation device to be integrated directly on the circuit board, which can make installation in the bicycle easy. Arranging the evaluation device on the circuit board enables a particularly compact, cost-effective and, alternatively or additionally, simple design. For example, no additional installation space or housing needs to be provided for the evaluation device. A thermal calculation model, for example, can be saved or filed on the circuit board or the evaluation device.Alternatively or additionally, a database can be stored or filed which determines the deviation between the temperature value and the motor winding temperature. This can be dependent on a temperature, a time gradient, a temporal temperature profile, or other factors. The evaluation device can additionally or alternatively comprise analog components which enable the motor winding temperature to be calculated. In one embodiment of the first and also the second aspect, the motor arrangement has a control device which is designed to control the electric motor depending on the temperature value. For example, the control device can be designed to control the electric motor depending on the current motor winding temperature determined by the evaluation device, whereby the control is also based on the temperature value.The control device can be designed to switch off the electric motor if the temperature value or the current motor winding temperature exceeds a threshold value. The control device can additionally or alternatively also be designed to limit the power of the electric motor depending on the temperature value or the current motor winding temperature. The control device can, for example, carry out derating. For example, the maximum power provided to the electric motor can be inversely proportional to the temperature value or the current motor winding temperature. Alternatively or additionally, the maximum power above a certain temperature value or a certain current motor winding temperature can be reduced by a fixed or proportional amount. Alternatively or additionally, a maximum speed or a maximum torque of the electric motor can also be limited depending on the temperature value or the current motor winding temperature.the current motor winding temperature.

[0035] Alternatively or additionally, a particularly high electrical power can be made available if the temperature value or the current motor winding temperature is particularly low.

[0036] The control device can, for example, comprise one or more microchips arranged on the circuit board. The control device can also comprise a memory chip arranged on the circuit board. This allows the control device to be integrated directly onto the circuit board, making installation in the bicycle easy. The control device and the evaluation device can be formed from the same components.

[0037] The described control device ensures safe operation of the electric motor. By limiting the available electrical power, melting or overheating, for example, can be avoided. Furthermore, the control device can, when a particularly low temperature is present, provide additional

[0038] This allows for a motor configuration with particularly high performance and simultaneously safe operation.

[0039] In one embodiment, the control device is arranged on the circuit board. The control device is configured, i.e., specifically prepared, for example, programmed, to control the motor assembly depending on the temperature value and, alternatively or additionally, the current motor winding temperature. The control device can have one or more interfaces. Thus, the control device can communicate with the various components of the motor assembly. The control device can have one or more components, which can be provided at the same or different locations on the circuit board.

[0040] In one embodiment of the first and also the second aspect, the temperature sensor is designed as a thermistor. A thermistor can be a hot wire or a cold wire. A hot wire is a temperature-dependent resistor which conducts current better at high temperatures than at low temperatures. A cold wire is a temperature-dependent resistor which conducts current better at low temperatures than at high temperatures. The temperature sensor can be designed as an NTC resistor. By being designed as a thermistor, the temperature sensor can be made particularly compact. Furthermore, a thermistor can have a particularly fast response time and additionally or alternatively a particularly wide temperature range. The thermal response time can be a period of time that a thermal system requires to react to a change in temperature.This means that a temperature can be measured particularly quickly, accurately, and additionally or alternatively over a particularly wide temperature range.

[0041] A third aspect relates to a bicycle with a motor arrangement according to the first aspect or the second aspect. Further features, embodiments, and advantages can be found in the descriptions of the first aspect and the second aspect. Conversely, features, embodiments, and advantages of the third aspect also represent features, embodiments, and advantages of the first or second aspect.

[0042] The bicycle can have an electrical energy source, which can be connected to the electric motor via the circuit board. The electrical energy source can be provided, for example, by a rechargeable battery, such as a lithium battery. The electrical energy source can also be a fuel cell, for example. The energy source can be connected to the electric motor via the plug.

[0043] Short description of the characters

[0044] Fig. 1 shows a schematic sectional view of an engine arrangement according to an embodiment of the present invention.

[0045] Fig. 2 shows a schematic sectional view of a motor arrangement according to another embodiment of the present invention.

[0046] Fig. 3 shows a schematic sectional view of a motor arrangement according to a further embodiment of the present invention from an end side.

[0047] Fig. 4 shows a schematic sectional view of a motor arrangement according to a further embodiment of the present invention from an end side.

[0048] Detailed description of the characters

[0049] Fig. 1 shows a schematic sectional view of a motor assembly 1 for a bicycle according to an embodiment of the present invention. It shows a cross-section along a longitudinal axis of the motor assembly 1. The motor assembly 1 has a housing 10 which encloses an electric motor 12. The housing 10 is shown in two parts here, whereby the connections between the individual parts are not shown. The housing 10 has a housing element 40 and a housing cover 42 fastened thereto. The housing cover 42 is designed as a bearing plate on which a motor shaft 20 is rotatably held via a rolling bearing 24. The electric motor 12 has a rotor 14 and a stator 16, wherein the stator 16 has at least one motor winding 18. The rotor 14 is placed on the motor shaft 20, which is rotatably mounted in the housing 10 via a rolling bearing 22 and the rolling bearing 24. In Figs.1 and 2, only an upper portion of these components is shown, with a lower half below the dot-dash line shown in the illustration only partially depicted. Furthermore, a right-hand portion of the engine assembly 1 is also not shown.

[0050] The stator 16 is non-rotatably mounted inside the housing 10, and the rotor 14 is non-rotatably connected to the motor shaft 20. The electric motor 12 is designed to generate a driving force on the motor shaft 20 via the rotor 14 during operation to assist a rider in propelling the bicycle. For this purpose, a magnetic field is generated by energizing the motor winding 18, which causes the rotor 14 to rotate. The rotor 14 has permanent magnets for this purpose.

[0051] The rolling bearings 22 and 24 allow the motor shaft 20 to rotate with low friction, while the housing 10 and the stator 16 do not rotate during operation.

[0052] The printed circuit board 26 is arranged axially to the left of the housing 10, adjacent to the housing cover 42. The printed circuit board 26 is fastened to the housing 10, here by electrically insulating pins 44. A plug 28 is fastened to the printed circuit board 26 and forms part of an electrical connection 30 between the printed circuit board 26 and the motor winding 18. The printed circuit board 26 can provide a current to the motor winding 18 for operating the electric motor 12 via the electrical connection 30. The electrical connection 30 has a copper conductor which ends in the motor winding 18 and is plugged into the plug 28. This conductor enables the connection 30 to have a particularly low thermal resistance between the motor winding 18 and the plug 28, so that the plug 28 quickly approximates the temperature of the motor winding 18. Thus, the plug 28 is connected to the electric motor 12 both electrically and thermally.The circuit board 26 is arranged in an interior space which is defined by the.

[0053] Housing cover 42 and a cover element 46 fastened to the housing 10 are formed. This interior space is separate from the interior space for the electric motor 12. A temperature sensor 32 is arranged on the circuit board 26 next to the plug 28. The temperature sensor 32 is designed to detect a temperature value of the motor winding 18. This is arranged on a side of the circuit board 26 facing away from the housing 10 and is arranged on the plug 28. In the embodiment shown, the temperature sensor 32 is fastened to the plug 28 with a thermally conductive adhesive 34 and is electrically connected to the circuit board 26 for transmitting a detected temperature value. The thermally conductive adhesive 34 has a particularly high thermal conductivity so that the temperature sensor 32 can easily detect a temperature at the plug 28.Thus, a particularly low thermal resistance or high thermal conductivity exists between the temperature sensor 32 and the motor winding 18 via the connector 28 and the copper conductor. The temperature sensor 32 is designed as an NTC resistor. This is connected to a control device 36, which is formed from electrical components arranged on the circuit board 26.

[0054] The control device 36 is configured to control the electric motor 12. For this purpose, the control device 36 is in contact with the electric motor 12 via the plug 28 in order to transmit electrical current to the electric motor 12. The control device 36 is configured to ensure safe operation of the electric motor 12. In the example shown, the control device 36 is configured to prevent overheating of the electric motor 12. For this purpose, the control device 36 is configured to reduce the power of the electric motor 12 if an excessively high current motor winding temperature is determined. The control device 36 can also switch off the electric motor 12 if an excessively high current motor winding temperature is determined.

[0055] The motor assembly 1 has an evaluation device designed to determine a current motor winding temperature depending on the temperature value detected by the temperature sensor 32. The evaluation device is formed by the control device 36 or other electrical components arranged on the circuit board 26. In a determination method used in the example shown, it can be assumed that the temperature value corresponds to the motor winding temperature with a constant offset. In another embodiment, the determination of a deviation of the current motor winding temperature from the detected temperature value is temperature-dependent and, alternatively or additionally, temperature gradient-dependent.

[0056] Fig. 2 shows a schematic sectional view of a motor assembly 1 according to a further embodiment of the present invention. This largely corresponds to Fig. 1, which is why only differences are described here. The arrangement of the temperature sensor 32 is different here, and the housing 10 with its

[0057] Housing cover 42 is designed differently. The function and temperature determination of the motor assembly 1 in the second embodiment are identical to the first embodiment.

[0058] The housing cover 42 of the housing 10 has a projection 38, which in Fig. 2 is formed axially to the left on a side facing the circuit board 26. The temperature sensor 32 is, in contrast to Fig. 1, arranged on the side of the circuit board 26 facing the housing 10. The temperature sensor 32 is further arranged adjacent to the projection 38 and contacted therewith, in the example shown via an optional thermal paste or an optional thermally conductive adhesive 34. The temperature sensor 32 is attached to the circuit board 26. In another embodiment, the temperature sensor 32 is alternatively or additionally attached to the projection 38.

[0059] Due to the heating of the motor winding 18, the housing 10 also heats up during operation. The projection 38 is arranged radially in the same area as the motor winding 18 and adjacent to the motor winding 18, whereby a temperature of the projection 38 follows a temperature of the motor winding 18 relatively precisely. Due to the projection 38, the motor arrangement 1 can have a low thermal resistance between the motor winding 18 and the temperature sensor 32, wherein the projection 38 quickly approximates the temperature of the motor winding 18. By positioning the temperature sensor 32 on the projection 38, a current motor winding temperature can thus also be easily determined, as already described with reference to the first embodiment. The evaluation device can, based on the temperature value detected by the temperature sensor 32 on the projection 38, determine a current

[0060] Calculate or estimate motor winding temperature.

[0061] Fig. 3 shows a schematic sectional view of a motor assembly 1 for a bicycle according to an embodiment of the present invention. It depicts a cross-section transverse to a longitudinal axis of the motor assembly 1. This embodiment largely corresponds to the motor assembly 1 shown in Fig. 1 or may correspond to this motor assembly 1. Additional visible details are described here. The circuit board 26 has three connectors 28, which form part of an electrical connection 30 between the circuit board 26 and the electric motor 12.

[0062] The motor assembly 1 shown in Fig. 3 has a temperature sensor 32, which is attached to one of the connectors 28 via the thermally conductive adhesive 34 and is electrically connected to the circuit board 26 for transmitting a detected temperature value. The temperature sensor 32 is arranged on a side of the circuit board 26 facing the motor windings 18. The temperature sensor 32 is attached to the centrally arranged connector 28 and arranged on a side of the circuit board 26 facing the housing 10. This central connector 28 can have a shorter electrical line for connecting to the motor windings 18 than the other connectors 28, whereby the temperature at the central connector 28 can adjust particularly quickly to the temperature of the motor windings 18.

[0063] The heat flow 48 via the electrical connections 30 of the motor windings 18 to the circuit board 26 is illustrated by three arrows that lead along the electrical connection 30 from the motor winding 18 to the circuit board 26.

[0064] Fig. 4 shows a schematic sectional view of a motor arrangement according to a further embodiment of the present invention. It shows a cross section transverse to a longitudinal axis of the motor arrangement 1. This embodiment largely corresponds to the embodiment in Fig. 2 or can correspond to the motor arrangement 1 shown there. The temperature sensor 32 is arranged on a side of the circuit board 26 facing the housing 10. The temperature sensor 32 is also arranged adjacent to a projection 38 of the housing 10 and is in contact with this projection 38 through the thermally conductive adhesive 34 or is contacted with this projection 38 without thermally conductive adhesive 34. A temperature measurement can thus be carried out as described with reference to Fig. 2, wherein the projection 38 quickly assumes approximately the temperature of the motor winding 18 due to the heat conduction through the housing 10.The corresponding heat flow 48 is schematically indicated here by three arrows that lead from the electric motor 12 via the housing 10 to the temperature sensor 32.

[0065] Reference symbol

[0066] Engine arrangement

[0067] Housing

[0068] electric motor

[0069] rotor

[0070] stator

[0071] Motor winding

[0072] Motor shaft

[0073] Rolling bearings

[0074] Rolling bearings

[0075] circuit board

[0076] Plug electrical connection of the circuit board with the electric motor

[0077] Temperature sensor

[0078] Thermally conductive adhesive

[0079] Control device

[0080] projection

[0081] Housing element

[0082] Housing cover

[0083] Pen

[0084] Cover element

[0085] Heat flow

Claims

Patent claims 1. Motor arrangement (1) for a bicycle, wherein the motor arrangement (1) comprises a housing (10), an electric motor (12), a printed circuit board (26) and a temperature sensor (32), wherein the electric motor (12) is arranged in the housing (10) and has a motor winding (18), wherein the printed circuit board (26) is arranged outside the housing (10) and has a plug (28) with which the printed circuit board (26) is electrically connected to the electric motor (12) for controlling the latter, wherein the temperature sensor (32) is designed to detect a temperature value of the motor winding (18), and wherein the temperature sensor (32) is arranged on the plug (28).

2. Motor arrangement (1) according to claim 1, characterized in that the temperature sensor (32) is connected to the plug (28) by a thermally conductive adhesive (34).

3. Motor arrangement (1) according to claim 1 or 2, characterized in that the temperature sensor (32) is arranged on a side of the circuit board (26) facing away from the housing (10).

4. Motor arrangement (1) according to claim 1 or 2, characterized in that the temperature sensor (32) is arranged on a side of the circuit board (26) facing the housing (10).

5. A motor assembly (1) for a bicycle, the motor assembly (1) comprising a housing (10), an electric motor (12), a circuit board (26), and a temperature sensor (32), the electric motor (12) being arranged in the housing (10) and comprising a motor winding (18), the circuit board (26) being arranged outside the housing (10) and being electrically connected to the electric motor (12) for controlling the latter, the temperature sensor (32) being designed to detect a temperature value of the motor winding (18), the temperature sensor (32) resting on the housing (10), and the housing (10) comprising a projection (38) projecting in the direction of the circuit board (26), on which projection the temperature sensor (32) rests.

6. Motor arrangement (1) according to claim 5, characterized in that the temperature sensor (32) is connected to the projection (38) of the housing (10) by a thermally conductive adhesive (34).

7. Motor arrangement (1) according to claim 5 or 6, characterized in that the temperature sensor (32) is arranged on a side of the circuit board (26) facing the housing (10).

8. Motor arrangement (1) according to one of the preceding claims, characterized in that the motor arrangement (1) has an evaluation device which is designed to determine a current motor winding temperature as a function of the temperature value.

9. Motor arrangement (1) according to claim 8, characterized in that the evaluation device is arranged on the printed circuit board (26).

10. Motor arrangement (1) according to one of the preceding claims, characterized in that the motor arrangement (1) has a control device (36) which is designed to control the electric motor (12) as a function of the temperature value.

11. Motor arrangement (1) according to claim 10, characterized in that the control device (36) is arranged on the printed circuit board (26).

12. Bicycle with a motor arrangement (1) according to one of the preceding claims and an electrical energy source which is connected to the electric motor (12) via the circuit board (26).

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