Device for detecting a rotation direction of an electric motor and assembly method for assembling a drive system

Abstract

The invention relates to a device for detecting a rotation direction of an electric motor, comprising: - a first Hall sensor with a first trigger threshold and a second Hall sensor with a second trigger threshold, for detecting a magnetic flux density generated during the operation of the electric motor, wherein a signal output of the first Hall sensor and a signal output of the second Hall sensor are connected in parallel and the two Hall sensors are configured to be arranged on the electric motor at an angle to one another during normal operation of the device, and to have unequal trigger thresholds; and - a control unit coupled to the parallel-connected signal output of the two Hall sensors for evaluating a common output signal of the two Hall sensors received via the common signal output, wherein the control unit is configured to detect the rotation direction based on the common output signal. Furthermore, the proposed solution also relates to a method for assembling a drive system.

Description

[0001] Device for detecting a direction of rotation of an electric motor and assembly method for assembling a drive system

[0002] Description

[0003] The proposed solution relates to a device for detecting a direction of rotation and to an assembly method for assembling a drive system with such a device. Such devices and assembly methods are known, in particular, from drive systems in the automotive sector. In particular, they are known for monitoring the power-operated adjustment of vehicle elements, such as vehicle seats, doors, or windows. The direction of rotation can be detected, for example, based on motor drive values ​​from a motor electronics system or a movement of an element driven by the motor. Such devices and methods can sometimes only inadequately detect a malfunction of the motor and / or are complex to assemble and maintain.

[0004] The proposed solution is therefore based on the task of improving devices and methods for detecting a direction of rotation of an electric motor.

[0005] This object is achieved with a device according to claim 1 and an assembly method according to claim 11. Accordingly, the proposed device for detecting a direction of rotation of an electric motor comprises at least: a first Hall sensor with a first trigger threshold and a second Hall sensor with a second trigger threshold for detecting a magnetic flux density generated during operation of the electric motor, wherein a first signal output of the first Hall sensor and a second signal output of the second Hall sensor are connected in parallel, and the two Hall sensors are configured to be arranged on the electric motor during normal operation of the device, to enclose an angle other than zero, and to have unequal trigger thresholds.and a control unit coupled to the parallel-connected signal outputs of the two Hall sensors for evaluating a common output signal of the two Hall sensors received from the parallel-connected signal outputs, wherein the control unit is configured to detect the direction of rotation based on the output signal.

[0006] The proposed solution makes it possible to determine the direction of rotation by evaluating exactly one signal, namely the shared output signal of the two Hall sensors connected in parallel. The shared output signal contains information from at least two Hall sensors spatially separated by the included angle. It is conceivable that exactly two or more than two Hall sensors are used. The at least two Hall sensors enclose the angle with their respective connecting lines to a rotation axis of the electric motor. As a result, during normal operation, the two Hall sensors are passed one after the other from a fictitious point on the rotor of the electric motor. Since both Hall sensors have different trigger thresholds, a reversal of the direction of rotation also changes the temporal relationship between the output signals generated by the Hall sensors.Accordingly, the shared output signal of the Hall sensors, which can be evaluated by the control unit due to the parallel connection, also differs. Thus, the proposed device makes it possible to determine the direction of rotation directly at the motor through direct measurement. In particular, the direction of rotation is determined without the aid of predefined motor drive values. This can reduce the probability of incorrect determination of the direction of rotation.

[0007] In conjunction with motor revolution detection, this can improve the determination of the adjustment travel caused by the electric motor. This can reduce the frequency of necessary calibrations of the electronics used to determine the adjustment travel, thus reducing maintenance effort. The proposed solution can also reduce the contacting effort and make the device more robust against malfunctions.

[0008] The two Hall sensors can each have multiple contacts, in particular three contacts. Each of the Hall sensors can be connected to a voltage source and a reference potential (ground) via two of the contacts. A parallel connection of the two Hall sensors can therefore mean that a voltage source is connected to the first contact of each of the two Hall sensors, the second contacts of both Hall sensors are at the same potential level as ground, and the third contacts of both Hall sensors are connected to exactly one signal input of the control unit.

[0009] It is also conceivable and possible for the second contacts of both Hall sensors to be electrically connected to each other. The output signal can be tapped as a voltage modulation at the parallel-connected ground contacts of both Hall sensors. For example, a measuring resistor can be placed between the ground potential and the parallel-connected ground contacts of the two Hall sensors, across which a falling voltage is measured and evaluated. Such an arrangement can be referred to as low-side detection.

[0010] It is also conceivable and possible to place the measuring resistor between a voltage source and the two parallel-connected power supply contacts. Such an arrangement can be referred to as high-side detection.

[0011] Furthermore, each of the Hall sensors is configured to generate an output signal depending on a magnetic flux density and to transmit this signal via the respective signal output. Since the output signal depends on the magnetic flux density, both Hall sensors exhibit different trigger thresholds. This means that the Hall sensors, which are intended to be mounted on the electric motor, exhibit different temporal behavior of the respective output signal in response to the magnetic field generated during operation of the electric motor. In relation to a time-varying magnetic field, the two Hall sensors are configured to switch at different times due to the different trigger thresholds.

[0012] For example, the different trigger thresholds can be realized by different threshold values ​​or sensitivities of the two Hall sensors. For example, the first Hall sensor can generate a specific output signal at a magnetic flux density at which the second Hall sensor does not yet generate a corresponding output signal.

[0013] Alternatively or additionally, during normal operation of the device, the two Hall sensors can be arranged on an electric motor in such a way that a maximum magnetic flux density generated during operation of the electric motor at the location of the first Hall sensor differs from a maximum magnetic flux density at the location of the second Hall sensor. This also makes it possible to implement different trigger thresholds for the two Hall sensors.

[0014] In a further embodiment of the proposed solution, the first Hall sensor and the second Hall sensor can be positioned at different distances from the electric motor when the Hall sensors are arranged on an electric motor as intended. This also makes it possible to implement different trigger thresholds for the two Hall sensors.

[0015] For example, the distance of each of the Hall sensors can be defined as the minimum distance of all points of a surface of the respective Hall sensor to a rotation axis of the motor.

[0016] It is also conceivable and possible to realize different trigger thresholds by means of a targeted magnetic shielding of one of the Hall sensors or two different shieldings of the two Hall sensors.

[0017] In another conceivable and possible embodiment of the proposed solution, different trigger thresholds can be realized by varying the orientation of the two Hall sensors relative to the electric motor. This allows different trigger thresholds to be realized using standard components. This can reduce component costs.

[0018] In principle, a Hall sensor can have a detection direction, whereby a detection sensitivity of a Hall sensor for magnetic fields is maximum along the detection direction.

[0019] In an exemplary embodiment of the differently aligned Hall sensors, these can have different angles between the detection directions of the two Hall sensors and a connecting line between the Hall sensor and the rotational axis of the electric motor. For example, one of the two Hall sensors can be aligned such that the detection direction of one Hall sensor is orthogonal to the connecting line between one Hall sensor and the rotational axis of the electric motor. The other of the two Hall sensors can be aligned such that the detection direction of the other Hall sensor encloses an angle other than 90° to the connecting line between the other Hall sensor and the rotational axis of the electric motor. In particular, the included angle can be 45°.

[0020] In a further embodiment of the proposed solution, the two differently aligned Hall sensors can be configured with a single 2D Hall sensor. This can reduce the installation space.

[0021] In principle, the control unit of the proposed device, which is intended to be mounted on an electric motor, can be configured to generate a further output signal containing information about the detected direction of rotation. The control unit can be connected to the engine electronics and / or the on-board electronics of a car and / or another device configured to monitor the direction of rotation in order to send the output signal to them. Thus, the proposed device can enable robust monitoring of the direction of rotation.

[0022] It is also conceivable and possible for the control unit to be configured to derive a further output signal from the output signal and to determine the direction of rotation based on the derived output signal. Accordingly, the control unit can be configured to determine the direction of rotation indirectly via the output signal.

[0023] For example, the additional output signal can be embodied as a binary signal. It is conceivable in this case that the additional output signal switches between the two possible values ​​with each voltage change of the output signal. As a result, each change in the value in the binary additional output signal can correspond to a switching operation in one of the Hall sensors. Thus, the temporal profile of the additional output signal as well as the temporal profile of the output signal can have a temporal pattern that depends on the direction of rotation. Thus, the control unit of the device intended to be arranged on an electric motor can be configured to detect the direction of rotation of the electric motor by analyzing the additional output signal. A dependence of the temporal pattern in the additional output signal on the direction of rotation can be more pronounced than the dependence of the temporal pattern in the output signal.Thus, determining the direction of rotation by evaluating the further output signal can increase detection reliability.

[0024] It is also conceivable and possible that the control unit of the proposed device could be a component of the motor electronics for controlling the motor. For example, the control unit could be part of an integrated circuit of the motor electronics. This could reduce the installation space for a motor with a device for detecting the direction of rotation and its assembly effort.

[0025] In a further embodiment of the proposed solution, the control unit can be configured to compare a temporal profile of the common output signal with a stored temporal profile for a clockwise rotation and with a stored temporal profile for a counterclockwise rotation. This can reduce the time required to detect the direction of rotation. Furthermore, the probability of an incorrect determination of the direction of rotation can be reduced.

[0026] To compare the temporal profile of the common output signal with the stored profile, the control unit can be designed with a memory and configured to retrieve data from the memory. The memory can contain information regarding the temporal profile for clockwise and counterclockwise rotation. For example, the memory can be a temporary memory, in particular a random access memory. This can reduce access times to the temporal profiles stored in the memory and thus further improve rapid determination of the direction of rotation.

[0027] In a further embodiment of the proposed device, the temporal profile of the output signal over a fraction of a complete revolution of a rotor of an electric motor can be used to detect the direction of rotation. In particular, the direction of rotation can be detected as soon as a magnetic flux density induced during operation of the electric motor has completed a complete period at the location of both Hall sensors.

[0028] In an exemplary embodiment of the proposed solution, the two Hall sensors are digital Hall sensors. This can simplify the signal processing of the output signal.

[0029] In a further embodiment of the proposed solution, the digital Hall sensors are latching Hall sensors. This can further simplify the signal processing of the common output signal.

[0030] A latching Hall sensor can be switched between two states. The Hall sensor stores its reading and can only be switched again by a magnetic field of opposite polarity and predetermined strength. The upper switching point, for switching from a first to a second state, is referred to as the upper operating point (BOP). The lower switching point, for switching from the second to the first state, is referred to as the release point (BRP).

[0031] Due to the spatial separation of the Hall sensors by the angle, the rotating magnetic field generated by the electric motor during operation causes the Hall sensors to switch at different times. Due to the different trigger thresholds, the switching can also occur at different switching points.

[0032] In a further embodiment of the proposed solution, the control unit can be configured to determine, in a temporal profile of the output signal, a ratio between a first time period in which both Hall sensors are in the same state and a second time period comprising the first period and a further period in which both Hall sensors are in different states. This can reduce the probability of erroneous detections and the time required to detect the direction of rotation.

[0033] By way of example, the first time period can relate to the time in which both Hall sensors are in their first state, i.e., they have been switched to the first state by the magnetic field induced during operation of the electric motor with a magnetic flux density corresponding to the BRP of the two Hall sensors, and neither of the two Hall sensors has yet switched from the magnetic field to the second state. By way of example, the second time period can begin at a point in time at which the second Hall sensor is switched to the first state by the magnetic field, but the first Hall sensor is still in the second state. Accordingly, the second time period can end at the point in time at which the first Hall sensor is switched to the second state, while the second Hall sensor is already in the second state.

[0034] The aforementioned ratio of the time durations can have different values ​​depending on the direction of rotation due to the different trigger thresholds. Thus, detection of the direction of rotation is possible by comparing the aforementioned ratio of the time durations with a known value for the direction of rotation.

[0035] By way of example, the control unit can be configured to detect the direction of rotation for which the stored ratio of the first time period to the second time period has the smaller deviation from the measured ratio.

[0036] According to a further embodiment of the proposed device, the first Hall sensor and the second Hall sensor can be components of a common integrated circuit of the device. This allows the spatial separation of both Hall sensors to be fixed and more robust against mechanical influences. This can increase reliability. Furthermore, the number of individual components of the proposed device can be reduced. This can reduce assembly time, space requirements, and costs. Furthermore, by arranging the two Hall sensors on a common circuit, common contacting is conceivable and possible. This can further reduce assembly effort.

[0037] The aforementioned object is also achieved by a drive system comprising an electric motor and the proposed device for detecting the direction of rotation of the electric motor. The two Hall sensors of the device are arranged on the electric motor at an angle to each other. This can enable the detection of the direction of rotation using the output signals of the two Hall sensors.

[0038] In a further embodiment of the proposed drive system, the two Hall sensors can be arranged on the electric motor in such a way that the maximum magnetic flux density acting on the first Hall sensor during motor operation is different from the maximum flux density acting on the second Hall sensor. This makes it possible to implement a different trigger threshold for the two Hall sensors. In a further embodiment of the proposed drive system, the first Hall sensor and the second Hall sensor can be at different distances from the electric motor. This also makes it possible to implement a different trigger threshold for the two Hall sensors.

[0039] In a further embodiment of the proposed drive system, the first Hall sensor and the second Hall sensor can have different orientations to the electric motor.

[0040] For example, the electric motor of the proposed drive system could be a brushless DC motor. This can increase the service life of the drive system and simplify operation.

[0041] For example, the electric motor can also be designed as an external rotor with a ring magnet. This can simplify the direction of rotation.

[0042] Furthermore, the proposed drive system can be configured to be contactable and operable with a four-wire wiring harness. The electric motor can be configured to be operated with two of the wires of the wiring harness. Furthermore, the proposed device for detecting the direction of rotation of the electric motor can be configured to be operated with the two remaining wires of the wiring harness. This can reduce the costs of the proposed drive system and assembly effort.

[0043] In particular, the proposed drive system can be configured to adjust an element of a motor vehicle by external power. For example, the element of the motor vehicle can be a vehicle seat, a door, a tailgate, a window, or a roof. Likewise, the proposed drive system can be a primary drive motor of a car.

[0044] The above statements on advantages and possible embodiments of the proposed device for detecting a direction of rotation of an electric motor also apply analogously to the proposed drive system.

[0045] The aforementioned problem is also solved by a vehicle seat with two components that can be adjusted relative to each other using the proposed drive system. This can improve user comfort and safety.

[0046] In addition, the object mentioned at the outset is also achieved by a vehicle having at least one adjustable vehicle part and a drive system coupled to the adjustable vehicle part for externally powered adjustment.

[0047] The above statements regarding advantages and possible configurations of the proposed drive system and the device for detecting a direction of rotation of an electric motor also apply analogously to the proposed vehicle seat and the proposed vehicle.

[0048] Furthermore, the object mentioned above is also achieved by an assembly method for assembling a drive system. The proposed assembly method comprises at least the following steps: an electric motor, a first Hall sensor with a first trigger threshold and a second Hall sensor with a second trigger threshold for detecting a magnetic flux density generated during operation of the electric motor, and a control unit are provided. The two Hall sensors are arranged at an angle to one another on the electric motor, wherein the two Hall sensors have unequal trigger thresholds. A signal output of the first Hall sensor and a signal output of the second Hall sensor are connected in parallel. The control unit is coupled to the parallel signal outputs of the two Hall sensors for evaluating a common output signal received from the parallel signal outputs of the two Hall sensors.

[0049] The proposed assembly method provides a drive system in which the direction of rotation can be determined by evaluating exactly one signal, namely the shared output signal of the two Hall sensors connected in parallel. The shared output signal contains information from the two Hall sensors spatially separated by an angle. This can reduce the probability of incorrect determinations of the direction of rotation. In conjunction with the detection of motor revolutions, this can improve the determination of an adjustment path caused by the electric motor. This can reduce the frequency of necessary calibrations of the electronics for determining the adjustment path and thus reduce maintenance effort. Likewise, the proposed solution can reduce the contacting effort and make the device more robust against malfunctions.

[0050] In an exemplary embodiment of the proposed assembly method, the proposed drive system can be provided.

[0051] All the above statements regarding advantages and possible configurations of the proposed device for detecting a direction of rotation of an electric motor and of the proposed drive system therefore also apply analogously to the proposed assembly method.

[0052] Furthermore, the aforementioned object is also achieved by a method for detecting the rotational direction of an electric motor using the proposed device. The control unit of the device receives the combined output signal of the two Hall sensors and detects the rotational direction based on the combined output signal.

[0053] In a further embodiment of the proposed method, the control unit can compare a temporal profile of the output signal with a stored temporal profile for a clockwise and counterclockwise rotation. This can enable faster and more precise detection of the rotation direction.

[0054] The aforementioned problem is also solved by a computer program product for execution on a processor of the control unit of the proposed device. Such a computer program product contains instructions that, when executed, cause the processor to execute the proposed method.

[0055] All the above statements regarding advantages and possible embodiments of the proposed device for detecting a direction of rotation of an electric motor and the proposed drive system apply analogously to the proposed method and computer program product.

[0056] The invention further relates to the use of a device for detecting a direction of rotation (RD) of an electric motor, as described and / or claimed herein, and / or of a drive system, as described and / or claimed herein, for controlling an electric adjustment device, in particular an electric seat adjustment device.

[0057] This allows the current position of the adjustment device to be determined along an adjustment path of the adjustment device. This information can then be used, for example, to control the electric motor of the adjustment device, as described below.

[0058] For example, this can be used to control the speed of the adjustment device's electric motor. The operation of an adjustment device, especially a vehicle seat, often requires that it be operated at varying speeds in order to achieve optimal adjustment perception for the user and / or to prevent damage to the adjustment device, for example, when it is moved to its end positions.

[0059] Furthermore, a safety component can be activated. This activation can occur, in particular, depending on the current position of the adjustment device along an adjustment path of the adjustment device, for example, depending on whether a passenger on a vehicle seat is positioned closer or further away from a dashboard or other interior components of a vehicle. Thus, it can be provided that at least two types of activation of the safety component exist, with a first type being activated in a first position and a second type being activated in a second position.

[0060] For example, at least one airbag can be activated. Activation can occur depending on the current position of the adjustment device along an adjustment path of the adjustment device. It can be provided that there are at least two types of airbag activation, with a first type being activated in a first position and a second type being activated in a second position. The two types can differ, for example, in the intensity of the deployment of the at least one airbag, the filled volume, and / or the type and number of activated airbags.

[0061] Furthermore, anti-pinch protection can be implemented for the adjustment mechanism. Control can be based on the current position of the adjustment mechanism along its adjustment path. This very precise position determination makes it possible to prevent collisions between a seat and other components or seats. Furthermore, occupants can be better protected, as the risk of limbs becoming trapped can be better avoided.

[0062] Furthermore, the activation and / or deactivation of a vehicle's autonomous ferry operation can be performed. This activation and / or deactivation can occur, in particular, depending on the current position of the adjustment device along an adjustment path of the adjustment device. If, for example, a driver is sitting too far away from the steering wheel, the deactivation of autonomous ferry operation can be prevented until the driver has been brought into a suitable position to assume control of the vehicle.

[0063] The adjustment device can be one or more selected from seat length adjustment device, seat height adjustment device,

[0064] Seat tilt adjustment device, seat depth adjustment device,

[0065] It can be a backrest adjustment device for a vehicle seat. It can also be an adjustment device that can be adjusted inside a vehicle seat.

[0066] In principle, individual aspects of individual embodiments of the proposed solution can be combined with each other.

[0067] Individual embodiments of the proposed solution are explained in more detail using the figures shown below.

[0068] Here we show:

[0069] Figure 1 is a schematic representation of a first embodiment of the proposed device with two Hall sensors and a control device in the intended state arranged on an electric motor,

[0070] Figure 2 shows an exemplary temporal course of a magnetic flux density at

[0071] Location of the Hall sensors from Figure 1 and a generated output signal of the Hall sensors,

[0072] Figure 3 shows a time profile of a further output signal derived from the output signal of Figure 1, Figure 4 shows a schematic representation of a second embodiment of the proposed device with two Hall sensors positioned differently from the electric motor,

[0073] Figure 5 is a circuit diagram of a third embodiment of the proposed

[0074] Device with two Hall sensors arranged on an integrated circuit,

[0075] Figure 6 is a schematic representation of the third embodiment,

[0076] Figure 7 exemplary procedure of the proposed

[0077] assembly process, and

[0078] Figure 8 exemplary procedure of the proposed procedure for

[0079] Detection of the direction of rotation.

[0080] Figure 1 shows a schematic representation of a first embodiment of the proposed device 100 for detecting a direction of rotation RD of an electric motor 400 in a state in which it is intended to be arranged on an electric motor 400. The device 100 comprises a first Hall sensor 111 which is arranged outside the electric motor 400 at a first distance d1 from a rotation axis RA of the electric motor 400. The device 100 further comprises a second Hall sensor 112 connected in parallel to the first Hall sensor 111 and likewise arranged outside the electric motor 400 at a second distance d2 from the rotation axis RA of the electric motor 400. The distances d1, d2 between the two Hall sensors 111, 112 are equal in the embodiment shown. The connecting lines between each of the Hall sensors 111, 112 and the rotation axis RA enclose an angle a1.A trigger threshold of the first Hall sensor 111 is different from the trigger threshold of the second Hall sensor 112. Both Hall sensors 111, 112 are connected in parallel and to an input of a control unit 113 of the device 100 in order to send a common output signal S1 to the control unit during operation of the electric motor 400. The control unit 113 is configured to read in the output signal S1 generated by the Hall sensors and sent to the control unit 113 and to evaluate it to detect the direction of rotation RD of the electric motor 400. The parallel contacting of the two Hall sensors 111, 112 with a voltage supply and a ground potential, which is known to those skilled in the art, is not shown in Figure 1 for reasons of clarity. In the exemplary embodiment shown in Figure 1, the electric motor 400 is designed as an external rotor with a two-pole rotor 410.In principle, however, other designs of electric motors 400 are also conceivable and possible.

[0081] Figure 2 shows a time course of a magnetic flux density B (left y-axis) in arbitrary units (au) at the location of the two Hall sensors 111, 112 from Figure 1 as well as a time course of the common output signal S1 (right y-axis) in arbitrary units (au) of both Hall sensors 111, 112. The magnetic flux density B is shown in the upper area of ​​the diagram. The output signal S1 is shown in the lower area of ​​the diagram. The time axis (t [au]) is divided into two intervals. The first interval t0 to t5 relates to a rotation of the electric motor 400 in the clockwise direction CW. The second interval from t5 to t10 relates to a rotation of the electric motor 400 in the counterclockwise direction CCW.

[0082] Over the entire time t0 to t10, the magnetic flux density B varies sinusoidally. Due to the angle a1, the magnetic flux density at the location of the first Hall sensor B(111) (dashed curve) is phase-shifted compared to the magnetic flux density at the location of the second Hall sensor B(112) (solid curve). Furthermore, the B-axis on the left in the diagram marks the lower switching point of the first Hall sensor BRP(111) (dashed line), the lower switching point of the second Hall sensor BRP(112) (solid line), the upper switching point of the first Hall sensor BOP(111) (dashed line), and the upper switching point of the second Hall sensor BOP(112) (solid line).

[0083] At the times t1, t2, t3, t4, t6, t7, t8 and t9 marked with vertical lines, a state switching of one of the two Hall sensors 111, 112 takes place. The times t1, t2, t3 and t4 lie in the time interval relating to the rotation of the electric motor 400 in the clockwise direction CW. At t1, the magnetic flux density at the location of the second Hall sensor B(112) passes the lower switching point of the second Hall sensor BRP(112), whereby the second Hall sensor 112 is switched from the second to the first state. At time t2, the magnetic flux density at the location of the first Hall sensor B(111) passes the lower switching point of the first Hall sensor BRP(111), whereby the first Hall sensor 111 is switched from the second to the first state.At time t3, the magnetic flux density at the location of the second Hall sensor B(112) passes the upper switching point of the second Hall sensor BOP(112), thereby switching the second Hall sensor 112 from the first to the second state. At time t4, the magnetic flux density at the location of the first Hall sensor B(111) passes the upper switching point of the first Hall sensor BOP(111), thereby switching the first Hall sensor 111 from the first to the second state.

[0084] Times t6, t7, t8, and t9, on the other hand, lie in the interval relating to the counterclockwise CCW rotation of the electric motor 400. At time t6, the magnetic flux density at the location of the first Hall sensor B(111) passes the lower switching point of the first Hall sensor BRP(111), thereby switching the first Hall sensor 111 from the second to the first state. At time t7, the magnetic flux density at the location of the second Hall sensor B(112) passes the lower switching point of the second Hall sensor BRP(112), thereby switching the second Hall sensor 112 from the second to the first state. At time t8, the magnetic flux density at the location of the first Hall sensor B(111) passes the upper switching point of the first Hall sensor BOP(111), thereby switching the first Hall sensor 111 from the first to the second state.At time t9, the magnetic flux density at the location of the second Hall sensor B(112) passes the upper switching point of the second Hall sensor BOP(112), whereby the second Hall sensor 112 is switched from the first to the second state.

[0085] This results in the common output signal S1 of the parallel-connected Hall sensors 111, 112, shown in the lower section of the diagram in Figure 2. The switching of the Hall sensors 111, 112 leads to a modulation of a voltage of the output signal S1. As an example, this modulation can be measured as a time-resolved voltage that drops across a measuring resistor that is in contact with the output signal S1 and ground. In the example curve shown in Figure 2, the voltage of the output signal S1 varies between the three voltage values ​​U1, U2, U3. With each switching operation of one of the two Hall sensors 111, 112, the measurable voltage changes. In accordance with the above explanations regarding the switching points BOP, BRP, the duration between t3 and t2 defines a first time period Δt1, in which both Hall sensors 111, 112 are in the same state.The duration from t1 to t4, on the other hand, defines a second time period At2, comprising the intervals t1 to t2 and t3 to t4, in which both Hall sensors 1 11 , 112 are in different states, as well as the aforementioned first time period At1.

[0086] Analogously, in the case of counterclockwise rotation CCW, the first time period At1 is defined as the duration from t7 to t8 and the second time period At2 is defined as the duration from t6 to t9.

[0087] The numerical ratio of the first time period At1 to the second time period At2 is approximately 48% for clockwise rotation (CW) and approximately 21% for counterclockwise rotation (CCW). Thus, the direction of rotation RD can be determined by determining the ratio of the first time period At1 to the second time period At2 and comparing a stored ratio for the two directions.

[0088] It is also conceivable and possible to derive a further output signal S2 from the output signal S1 and to determine the rotation direction RD based on the derived output signal S2. Since such an output signal S2 is derived from the output signal S1, the rotation direction RD is determined indirectly via the output signal S1.

[0089] Figure 3 shows an exemplary embodiment of a further output signal S2 derived from the output signal S1. In this case, the further output signal S2 is a binary signal which can assume the voltage values ​​U4 or U5. With each voltage change of the output signal S1, the further output signal S2 is switched from the previously present voltage value U4, U5 to the other voltage value U4, U5. As a result, each voltage change of the further output signal S2 also corresponds to a switching operation of one of the Hall sensors 111, 112. In this case, the further output signal S2 always has the one voltage value U5 when the two Hall sensors 111, 112 are switched to different states. The one voltage value U5 of the further output signal S2 therefore correlates with the average voltage value U2 of the first output signal S1.If both Hall sensors 111, 112 are switched to the same states, the further output signal S2 has the other voltage value U6. As shown by way of example in Figure 3, the time periods during which the two Hall sensors 111, 112 are in the same or different states vary depending on the direction of rotation RD. Thus, the time course of the further output signal S2, as well as the time course of the output signal S1, shows a pattern that depends on the direction of rotation RD. In particular, the further output signal S2 depends on the direction of rotation RD by determining the ratio of a duration Δt3 during which one voltage value U5 is present to a duration Δt4 during which one voltage value U4 is present. In the present example, the ratio Δt3 / Δt4 during the time of rotation along the clockwise direction CW is approximately 200%.The ratio Δt3 / Δt4 during counterclockwise rotation (CCW) is approximately 50%. Thus, the ratios Δt3 / Δt4 differ more significantly for different rotation directions RD than the ratios Δt1 / Δt2 in the output signal S1. Therefore, determining the rotation direction RD via the additional output signal S2 can be more robust than determining the rotation direction RD via the additional output signal S1.

[0090] In other conceivable and possible embodiments of the proposed device 100, 200, 300, the temporal behavior of the magnetic flux density B and the output signals S1, S2 may deviate from the temporal behavior of the magnetic flux density B shown in Figures 2 and 3. For example, the magnetic flux density at the location of the first and second Hall sensors B(111, 112, 211, 212, 311, 312) may differ from one another in more aspects than just a phase shift. This may be the case in particular if the amplitude of the magnetic flux density at the location of one of the Hall sensors B(111, 112, 211, 212, 311, 312) is lower in magnitude than the amplitude at the location of the other Hall sensor.

[0091] For example, this can be realized by magnetic shielding of one of the Hall sensors 111, 112, 211, 212, 311, 312 or by different distances d1, d2 of the Hall sensors 111, 112, 211, 212, 311, 312 to the electric motor 400.

[0092] Figure 4 shows a schematic representation of a second embodiment of the proposed device 200. In this case, the distance d2 of the second Hall sensor 212 is greater than the distance d1 of the first Hall sensor 211 by a distance difference Ad. Due to the distance dependence of the magnetic flux density B generated by the electric motor 400 during operation, the magnetic flux density B(212) acting over time at the location of the second Hall sensor 212 not only corresponds to a phase-shifted flux density at the location of the first Hall sensor B(211). Rather, the amplitude of the temporal variation of the magnetic flux density at the location of the second Hall sensor B(212) is also reduced compared to the flux density at the first Hall sensor (B211). This allows a different trigger threshold to be realized even when using identical Hall sensors 211, 212.

[0093] In further conceivable and possible embodiments of the proposed device 100, 200, 300, the angle a1, a2 can assume significantly smaller or larger values. In particular, it is conceivable to combine the two Hall sensors in one component and thus design them with a significantly smaller angle a1, a2 than the angle a1 shown in Figure 4. For this purpose, Figure 5 shows a circuit diagram of an exemplary embodiment of the proposed device 300, in which both Hall sensors 311, 312 are arranged and contacted on a common integrated circuit IC. The installation space can thus be reduced compared to the embodiments from Figures 1-4. Each of the Hall sensors 311, 312 has three contacts. One contact is for the supply voltage, one contact is for connection to a ground potential, and one connection is for outputting an output signal.On the internal circuit IC, the contacts for the supply voltage are connected in parallel to a first contact C1 of the internal circuit. The contacts for the output signal are also connected in parallel to a second contact C2 of the internal circuit. The contacts of the two Hall sensors 311, 312 are electrically connected on the internal circuit IS. To operate the device 300 shown in Figure 5, it is connected via the contacts C1, C2 of the integrated circuit IC to a voltage source P and the control unit 313 of the device 300. The voltage source P is connected to C1 and, as shown, the control unit 313 is connected to C2. In the embodiment shown in Figure 5, the control unit 313 is set up to measure a voltage drop across a measuring resistor in order to determine the direction of rotation RD of an electric motor via the output signal S1.For this purpose, the measuring resistor is connected to both the second contact C2 and a ground potential. This arrangement of the control unit 313 corresponds to low-side detection.

[0094] In further embodiments, an arrangement of the control unit 313 for measuring a voltage modulation on the supply side between the voltage source P and the first contact C1 is also conceivable and possible. Such an arrangement of the control unit 313 corresponds to high-side detection.

[0095] Figure 6 shows the embodiment of Figure 5 in a state in which it is mounted as intended on an electric motor 400. The Hall sensors 311, 312, arranged on a common integrated circuit IC, have essentially the same distances d1, d2 from the rotational axis RA of the electric motor 400 and enclose the angle a2. The control unit 313 is connected to contact C2 to evaluate the output signal S1 of the two Hall sensors 311, 312.

[0096] Figure 7 shows a first possible sequence of the proposed assembly method for assembling a work system. Accordingly, in a first step, an electric motor 400, a first Hall sensor 111, 211, 311 with a first trigger threshold, and a second Hall sensor 112, 212, 312 with a second trigger threshold for detecting a magnetic flux density B generated during operation of the electric motor 400, as well as a control unit 113, 213, 313, are provided. Furthermore, the two Hall sensors 111, 112, 211, 212, 311, 312 are arranged on the electric motor 400 at an angle a1, a2 to each other, wherein the two Hall sensors 111, 112, 211, 212, 311, 312 have unequal trigger thresholds. In a third step, a signal output of the first Hall sensor 111, 211, 311 and a signal output of the second Hall sensor 112, 212, 312 are connected in parallel.In a fourth step, the control unit 113, 213, 313 is coupled to the parallel-connected signal outputs of the two Hall sensors 111, 112, 211, 212, 311, 312 in order to evaluate a common output signal S1 received from the parallel-connected signal outputs of the two Hall sensors 111, 112, 211, 212, 311, 312.

[0097] In principle, the sequence of process steps shown here does not imply a necessary order, so it is also conceivable to carry out the assembly steps in a different order than the one shown.

[0098] Figure 8 shows a possible embodiment of the proposed method for detecting a direction of rotation. Here, the control unit first receives the common output signal S1 and then evaluates it as follows. In a first step, the first time period Δt1 and the second time period Δt2 are determined in the temporal progression of the output signal S1 in accordance with the explanations for Figure 2. Accordingly, the first time period Δt1 relates to the time in which both Hall sensors 111, 112, 211, 212, 311, 312 are in their first state, i.e. have been switched to the first state by the magnetic field with a magnetic flux density B corresponding to the BRP caused during operation of the electric motor 400 and neither of the two Hall sensors 111, 112, 211, 212, 311, 312 has yet been switched to the second state by the magnetic field.The second time period Δt2 begins as soon as the second Hall sensor 112, 212, 312 is switched to the first state by the magnetic field, but the first Hall sensor 111, 211, 311 is still in the second state. The second time period Δt2 ends as soon as the first Hall sensor 111, 211, 311 is switched to the second state, while the second Hall sensor 112, 212, 312 is already in the second state.

[0099] Furthermore, the evaluation of the output signal S1 includes comparing the ratio of the first time period Δt1 to the second time period Δt2 with stored values ​​of the ratio for a clockwise CW and counterclockwise CCW rotation. Based on the comparison, in a final sub-step of the evaluation, the rotation direction RD of the electric motor 400 is determined as clockwise CW or counterclockwise CCW.

[0100] List of reference symbols

[0101] 100, 200, 300 Device for detecting the direction of rotation

[0102] 111, 211, 311 first Hall sensor

[0103] 112, 212, 312 second Hall sensor a1 , a2 angle

[0104] S1 , S2 output signal

[0105] 113, 213, 313 Control unit d1 , d2 distance

[0106] Ad distance difference

[0107] C1 , C2 contacts of the integrated circuit

[0108] IC Integrated Circuit

[0109] P voltage source

[0110] 400 electric motor

[0111] 410 Rotor

[0112] RD Rotation direction

[0113] RA rotation axis

[0114] CW clockwise

[0115] CCW Counterclockwise

[0116] B Magnetic flux density

[0117] BOP upper switching point

[0118] BRP lower switching point t1, t2, t3, t4, t5, t6, t7, t8, t9 time

[0119] At1, At2, At3, At4 duration

Claims

Claims 1. Device (100, 200, 300) for detecting a direction of rotation (RD) of an electric motor (400), comprising: a first Hall sensor (111, 211, 311) with a first trigger threshold and a second Hall sensor (112, 212, 312) with a second trigger threshold for detecting a magnetic flux density (B) generated during operation of the electric motor (400), wherein a signal output of the first Hall sensor (111, 211, 311) and a signal output of the second Hall sensor (112, 212, 312) are connected in parallel, and the two Hall sensors (111, 112, 211, 212, 311, 312) are configured, in a proper operation of the device (100, 200, 300), with an angle (a1, a2) to each other on the electric motor (400) and to have unequal trigger thresholds, and a control unit (113, 213,313) for evaluating a common output signal (S1) of the two Hall sensors (111, 112, 211, 212, 311, 312) received from the parallel-connected signal outputs, wherein the control unit (113, 213, 313) is configured to detect the direction of rotation (RD) based on the common output signal (S1).

2. Device (100, 200, 300) according to claim 1, characterized in that the control unit (113, 213, 313) is set up to compare a time profile of the output signal (S1) with a stored time profile for a clockwise (CW) and counterclockwise (CW) rotation.

3. Device (100, 200, 300) according to claim 1 or 2, characterized in that the Hall sensors (111, 112, 211, 212, 311, 312) are latching Hall sensors.

4. Device (100, 200, 300) according to one of the preceding claims, characterized in that the control unit (113, 213, 313) is set up to determine, in the time course of the output signal (S1), a ratio between a first time period (At1), in which both Hall sensors (111, 112, 211, 212, 311, 312) are in the same state, to a second time period (At2), comprising the first period and a further period in which both Hall sensors (111, 112, 211, 212, 311, 312) are in different states.

5. Device (100, 200, 300) according to one of the preceding claims, characterized in that the first Hall sensor (311) and the second Hall sensor (312) are components on a common integrated circuit (IC).

6. Drive system comprising an electric motor (400) and a device (100, 200, 300) for detecting a direction of rotation (RD) of the electric motor (400) according to one of claims 1 to 5, wherein the two Hall sensors (111, 112, 211, 212, 311, 312) of the device (100, 200, 300) are arranged at an angle (a1, a2) to one another on the electric motor (400).

7. Drive system according to claim 6, characterized in that the two Hall sensors (211, 212) are arranged on the electric motor (400) in such a way that a maximum magnetic flux density (B) acting on the first Hall sensor (211) during operation of the motor is not equal to a maximum flux density on the second Hall sensor (212).

8. Drive system according to claim 6 or 7, characterized in that the first Hall sensor (211) and the second Hall sensor (212) have different distances from the electric motor (400).

9. Drive system according to one of claims 6 to 8, characterized in that the first Hall sensor (211) and the second Hall sensor (212) have different orientations to the electric motor (400).

10. Vehicle seat with two components which are adjustable relative to one another by a drive system according to one of claims 6 to 9.

11. Assembly method for assembling a drive system, wherein: an electric motor (400), a first Hall sensor (111, 211, 311) with a first trigger threshold and a second Hall sensor (112, 212, 312) with a second trigger threshold for detecting a magnetic flux density (B) generated during operation of the electric motor (400) and a control unit (113, 213, 313) are provided, the two Hall sensors (111, 112, 211, 212, 311, 312) are arranged at an angle (a1, a2) to each other on the electric motor (400), wherein the both Hall sensors (111, 112, 211, 212, 311, 312) have unequal trigger thresholds, a signal output of the first Hall sensor (111, 211, 311) and a signal output of the second Hall sensor (112, 212, 312) are connected in parallel, and the control unit (113, 213, 313) is coupled to the parallel-connected signal outputs of the two Hall sensors (111, 112, 211, 212, 311, 312) for evaluating a common output signal (S1) received from the parallel-connected signal outputs of the two Hall sensors (111, 112, 211, 212, 311, 312).

12. Assembly method according to claim 11, characterized in that the assembled drive system is a drive system according to one of claims 6 to 8.

13. Method for detecting a direction of rotation (RD) of an electric motor (400), with a device (100, 200, 300) according to one of claims 1 to 5, wherein the control unit (113, 213, 313) of the device (100, 200, 300) receives the common output signal (S1) of the two Hall sensors (111, 112, 211, 212, 311, 312) and detects the direction of rotation (RD) based on the common output signal (S1).

14. The method according to claim 13, characterized in that the control unit (113, 213, 313) compares a time profile of the output signal (S1) with a stored time profile for a clockwise (CW) and counterclockwise (CW) rotation.

15. A computer program product for execution on a processor of the control unit (113, 213, 313) of the device (100, 200, 300) according to any one of claims 1 to 5, wherein the computer program product contains instructions which, when executed, cause the processor to execute a method according to any one of claims 13 or 14.

16. Use of a device (100, 200, 300) for detecting a direction of rotation (RD) of an electric motor (400) according to one of the preceding claims and / or of a drive system according to one of the preceding claims for controlling an electrical adjustment device, in particular an electrical Seat adjustment device.

17. Use according to claim 16, characterized in that a determination of the current position of the adjustment device is carried out along an adjustment path of the adjustment device.

18. Use according to claim 16 or 17, characterized in that a speed control of the electric motor (400) of the adjustment device is carried out.

19. Use according to one of the preceding claims, characterized in that an activation of a safety component is carried out, in particular depending on the current position of the adjustment device along an adjustment path of the adjustment device.

20. Use according to claim 19, characterized in that an activation of at least one airbag is carried out, in particular depending on the current position of the adjustment device along an adjustment path of the adjustment device.

21. Use according to one of the preceding claims, characterized in that a pinch protection is provided for the adjustment device, in particular depending on the current position of the adjustment device along an adjustment path of the adjustment device.

22. Use according to one of the preceding claims, characterized in that an activation and / or deactivation of an autonomous ferry operation of a vehicle is carried out, in particular depending on the current position of the adjustment device along an adjustment path of the adjustment device.

23. Use according to one of the preceding claims, characterized in that the adjustment device is a seat longitudinal adjustment device of a vehicle seat.

24. Use according to one of the preceding claims, characterized in that the adjustment device is a seat height adjustment device of a vehicle seat.

25. Use according to one of the preceding claims, characterized in that the adjustment device is a seat inclination adjustment device of a vehicle seat.

26. Use according to one of the preceding claims, characterized in that the adjustment device is a seat depth adjustment device of a vehicle seat.

27. Use according to one of the preceding claims, characterized in that the adjustment device is a backrest adjustment device of a vehicle seat.

28. Use according to one of the preceding claims, characterized in that the adjustment device is an adjustment device adjustable in the interior of a vehicle seat. * * * * *

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