Torque transmission device with a control system for determining the direction of rotation of the rotor

Description

[0001] The invention relates to a torque transmission device according to the preamble of claim 1.

[0002] A torque transmission device comprising an electric motor with a stator and a rotor rotatable relative to it is generally known. For example, such torque transmission devices are used in the powertrain of a motor vehicle. Such a powertrain can be part of a hybrid drive system, in which an internal combustion engine is used in addition to the electric motor.

[0003] To commutation an electric motor, it is necessary to know the rotor's rotational position, that is, its angular position. Various sensors can be used for this purpose, such as magnetic field-based or optical sensors. For example, German patent application DE 10 2017 113 627 describes a resolver that enables the detection of the rotor's angular position. A resolver is an additional component that requires installation space, resulting in increased design complexity and additional costs.

[0004] From DE 10 2016 211 837 A1, a method for determining the position of a rotor of a commutated electric motor is known, in which the electric motor is rotated and the voltage induced in the three phases of the electric motor and the corresponding back EMF are measured. Based on this measurement, the angular position of the rotor can then be determined. The rotor can be rotated externally or driven electrically by itself, in which case the induced voltage is measured at a non-current-carrying output of the electric motor.

[0005] When an electric motor is actively set in motion by a current pulse, this can result in the rotor rotating in either direction. However, when the rotor is coupled to an internal combustion engine, rotation in the wrong direction can damage or even destroy the engine.

[0006] A torque transmission device according to the preamble of claim 1 is known from DE 199 43 036 A1.

[0007] Regarding further state of the art, reference is made to DE 10 2014 206 330 A1 and DE 10 2012 203 611 A1.

[0008] The object of the present invention is to propose a torque transmission device that reduces or prevents the risk of damage to or destruction of the internal combustion engine. Furthermore, it is an object of the present invention to eliminate the need for a sensor or resolver for detecting the rotational position of the rotor relative to the stator. The installation space required for a torque transmission device is also to be reduced. A further object is to improve a torque transmission device.

[0009] At least one of these tasks is solved by a torque transmission device having the features according to claim 1.Accordingly, a torque transmission device, particularly in a drive train of a motor vehicle, is proposed, comprising an electric motor with a stator and a rotor rotatable relative to the stator, a control system that can output a current pulse to the electric motor, wherein the current pulse causes a rotational movement of the rotor in a first direction of rotation and by a first angle of rotation and thereby an induced voltage which is received by the control system and by which the control system determines the direction of rotation and / or the rotational position of the rotor with respect to the stator, wherein the rotor is connected to a torsional vibration damper comprising a damper input and a damper output, wherein the damper output is rotatable relative to the damper input to a limited extent against the effect of energy storage elements and the rotational movement of the rotor can cause a relative rotation between the damper input and the damper output.This eliminates the need for a sensor or resolver to detect the rotor's angular position relative to the stator. It also reduces the space required for the torque transmission device, allowing for a shorter design and overall improvement.

[0010] The electrical pulse can cause a brief, dynamic rotational movement of the rotor. This rotational movement is primarily characterized by a changing angular acceleration.

[0011] The torsional vibration damper can be designed as a dual-mass flywheel. It can operate in an oil bath (i.e., wet) or be designed to run dry. Grease lubrication, particularly of the energy storage elements, can be provided. The energy storage elements can be designed as springs, especially as arc springs.

[0012] The control system can include motor control for commutation of the electric motor. The control system can control the electric motor via three motor phases.

[0013] Detecting the direction of rotation and / or the position of the rotor may be necessary during any learning process of the motor control, for example during the initial commissioning of the torque transmission device, after towing the vehicle comprising the torque transmission device or after changing the power supply, especially for the control system.

[0014] The rotational position includes at least the detection of the rotor's angular position.

[0015] The electric motor is electrically controlled by at least three motor phases, whereby the control system outputs the current pulse via the first motor phase and reads the induced voltage via the second and third motor phases.

[0016] In a particularly advantageous embodiment of the invention, the rotor is connected to the damper outlet, and the rotational movement of the rotor causes the damper outlet to rotate by a second angle. The second angle can be equal to, less than, or greater than the first angle. The rotor can be fixed to the damper outlet.

[0017] In a specific embodiment of the invention, a crankshaft of an internal combustion engine is connected to the damper inlet. The crankshaft can be connected to the damper inlet in a rotationally fixed manner.

[0018] In a preferred embodiment of the invention, the current pulse is output when the internal combustion engine is stationary, i.e., not rotating. Detection of the direction and / or the rotor's position can be performed when the internal combustion engine is stationary. When the internal combustion engine is rotating, the motor's position and / or direction of rotation can also be detected by measuring the voltage induced by the rotor's rotation across two motor phases. This can be done while the torque transmission device is operating.

[0019] In a particularly preferred embodiment of the invention, the rotational movement of the rotor causes the damper inlet to rotate by a third angle of rotation, which is smaller than the first and / or second angles of rotation, preferably zero. This prevents damage or destruction of the internal combustion engine should the rotational movement of the rotor and the associated crankshaft, induced by the electrical pulse, occur in the negative, i.e., incorrect, direction of rotation of the combustion engine. The energy storage elements of the torsional vibration damper are able to absorb the kinetic energy of the dynamic rotational movement of the rotor, store it as potential energy, and release it again in the form of kinetic energy. The absorption and release of the kinetic energy preferably occurs at and from the damper outlet. Transmission of the rotational movement from the rotor to the combustion engine can be prevented or reduced.

[0020] In another particularly advantageous embodiment of the invention, the electric motor is designed as a starter generator and can mechanically start the combustion engine.

[0021] In a special embodiment of the invention, the electric motor is connected to the torsional vibration damper via a gearbox.

[0022] In a further preferred embodiment of the invention, the internal combustion engine can transmit torque to an output side via a knock-out clutch and / or transmit torque to the electric motor.

[0023] In a specific embodiment of the invention, a second electric motor is provided for transmitting torque to the output side, for example, vehicle wheels. The electric motor can be configured as a generator and as a starter, and the second electric motor can serve as a drive element for propelling the vehicle.

[0024] The combustion engine can provide mechanical energy to the electric motor, which the electric motor can then convert into electrical energy. This electrical energy can be used to power a battery and / or a second electric motor. In the latter case, this is a series hybrid powertrain.

[0025] The combustion engine can supply its mechanical energy for propelling the vehicle exclusively to the electric motor, or alternatively or additionally mechanically to a power output, such as the vehicle wheels. This configuration corresponds to a series power-split hybrid powertrain.

[0026] Further advantages and advantageous embodiments of the invention will become apparent from the description of the figures and the illustrations. Character description

[0027] The invention is described in detail below with reference to the illustration. It shows: Figure 1: A torque transmission device in a special embodiment of the invention.

[0028] Figure 1 Figure 1 shows a torque transmission device 10 in a specific embodiment of the invention. The torque transmission device 10 is part of a powertrain 11, in particular a hybrid powertrain of a motor vehicle.

[0029] The powertrain 11 comprises an internal combustion engine 12 for providing mechanical energy, which is connected to a torsional vibration damper 14. A crankshaft 16 of the internal combustion engine 12 is rotationally fixed to a damper inlet 18 of the torsional vibration damper 14. The damper inlet 18 is rotatable to a limited extent relative to a damper outlet 22, counteracting the action of energy storage elements 20. The damper outlet 22 is connected via a gearbox 24 to a rotor 26 of an electric motor 28.

[0030] The electric motor 28 further comprises a stator 30, relative to which the rotor 26 has a specific rotational position, i.e., a specific angular position. This rotational position is crucial for determining the commutation of the electric motor 28. It is therefore essential to determine both the direction of rotation of the electric motor 28 and its rotational position relative to the stator 30 in order to adjust the commutation of the electric motor 28 accordingly.

[0031] The rotational position of the rotor 26 is usually detected by sensors or by a hypothetical resolver 32 (shown here with a dashed line, but not required). According to the present invention, a control system 34, which controls the electric motor 28 via motor phases 36, outputs a current pulse to the electric motor 28. This current pulse causes the rotor 26 to rotate in a first direction and by a first angle, thereby inducing a voltage that can be received by the control system 34. This enables the control system 34 to determine the direction of rotation and / or the rotational position of the rotor 26 relative to the stator 30.

[0032] The electric motor 28 is designed as a generator and / or starter for starting the internal combustion engine 12. For this purpose, there is a mechanical connection between the rotor 26 of the electric motor 28 and the crankshaft 16 of the internal combustion engine 12. A uniform rotational movement of the rotor 26 thus causes a uniform rotational movement of the crankshaft 16 of the internal combustion engine 12.

[0033] Should the rotor 26 of the electric motor 28 rotate in a negative direction, that is, in the wrong direction relative to the internal combustion engine 12, this can lead to the destruction of the internal combustion engine 12. To detect the direction and / or the rotational position of the rotor 26, the control system 34 applies a current pulse to a motor phase 36, causing the rotor 26 to rotate by a first angle. This rotation by the first angle is transmitted to the damper output 22, which then rotates by a second angle, which may be equal to the first angle.

[0034] The energy storage elements 20 act as mechanical buffers, preventing the transmission of dynamic rotational motion from the damper outlet 22 to the damper inlet 18. Should the rotor 26 rotate in the wrong direction relative to the internal combustion engine 12, the rotational motion caused by the current pulse is absorbed by the energy storage elements 20 and advantageously not transmitted to the crankshaft 16. This prevents damage or destruction of the internal combustion engine 12 in the event of rotational motion of the rotor 26 initiated by the control system 34.

[0035] The internal combustion engine 12 can transmit torque via a knock-out clutch 38 to an output side 46, for example, to a vehicle axle 42 driving the vehicle wheels 40. When the knock-out clutch is open, the torque is transmitted from the internal combustion engine 12 exclusively to the electric motor 28. The electric motor 28 can supply a second electric motor 43 and / or a battery 44 with electrical energy. This is a series hybrid powertrain if the electric motor 28 is intended to supply electrical energy to the second electric motor 43, which drives the vehicle axle 42.

[0036] The combustion engine 12 can supply its mechanical energy for propelling the vehicle exclusively to the electric motor 28, or alternatively or additionally mechanically to the output side 46, for example, the vehicle axle 42. This configuration corresponds to a series power-split hybrid drivetrain. The torque required for propelling the vehicle can be supplied either exclusively by the second electric motor 43, exclusively by the combustion engine 12, or proportionally by both. Reference symbol list

[0037] 10 Torque transmission device 11 Drivetrain 12 Internal combustion engine 14 Torsional vibration damper 16 Crankshaft 18 Damper input 20 Energy storage elements 22 Damper output 24 Transmission 26 Rotor 28 Electric motor 30 Stator 32 Resolver 34 Control system 36 Motor phase 38 KO coupling 40 Vehicle wheel 42 Vehicle axle 43 Electric motor 44 Battery 46 Output side

Claims

1. A torque transfer device (10), in particular in a drive train (11) of a motor vehicle, wherein the torque transfer device (10) has: an electric motor (28), which can be electrically controlled by at least three motor phases (36) and has a stator (30) and a rotor (26) which can be rotated relative to the stator, a control system (34), which outputs a current pulse to the electric motor (28), which causes a rotary motion of the rotor (26) in a first direction of rotation and through a first angle of rotation and thus induces an induced voltage, and a torsional vibration damper (14) having a damper input (18) and a damper output (22), wherein the rotor (26) is connected to the torsional vibration damper (14), the damper output (22) can be rotated to a limited extent against the effect of energy storage elements (20) relative to the damper input (18), and the rotary motion of the rotor (26) causes a relative rotation between the damper input (18) and the damper output (22), characterised in that the induced voltage is received by the control system (34) and the control system (34) determines a direction of rotation and / or a rotational position of the rotor (26) with respect to the stator (30) by means of the induced voltage, and the control system (34) outputs the current pulse via a first motor phase (36) and reads out the induced voltage via a second and a third motor phase (36), such that the motor control for commutation of the electric motor is carried out without sensors.

2. The torque transmission device (10) according to claim 1, characterised in that the rotor (26) is connected to the damper output (22) and the rotary motion of the rotor (26) causes a rotary motion of the damper output (22) through a second angle of rotation.

3. The torque transmission device (10) according to claim 2, characterised in that the rotary motion of the rotor (26) causes a rotary motion of the damper input (18) through a third angle of rotation that is smaller than the first and / or second angle of rotation, preferably zero.

4. The torque transmission device (10) according to any one of claims 1 to 3, characterised in that a crankshaft (16) of an internal combustion engine (12) is connected to the damper input (18).

5. The torque transmission device (10) according to claim 4, characterised in that the current pulse is output when the internal combustion engine (12) is stationary, i.e. not rotating.

6. The torque transmission device (10) according to claim 4 or 5, characterised in that the electric motor (28) is designed as a starter generator and starts the internal combustion engine (12) mechanically.

7. The torque transmission device (10) according to any one of claims 4 to 6, characterised in that the internal combustion engine (12) transmits a torque via a K0 clutch (38) to an output side (46) and / or a torque to the electric motor (28).

8. The torque transmission device (10) according to any one of claims 1 to 7, characterised in that the electric motor (28) is connected to the torsional vibration damper (14) via a transmission (24).

9. The torque transmission device (10) according to any one of claims 1 to 9, characterised in that a second electric motor (43) is provided for transmitting torque to the output side (46).