DE102021125109A1 - Crank mechanism for an internal combustion engine of a motor vehicle - Google Patents

Abstract

The invention relates to a crank drive (3) for an internal combustion engine (2) of a motor vehicle, with an output shaft (5) which can be rotated relative to a housing element (4) of the internal combustion engine (2), with an electrical machine (15) having a rotor (16). , by means of which the output shaft (5) can be driven via the rotor (16) to start the internal combustion engine (2), and with a mass balance (19) which can be driven by at least one of the output shaft (5) and is therefore relative to the housing element (4 ) has a rotatable balancer shaft (20) coupled to the output shaft for balancing inertial forces of the crank mechanism (3), the balancer shaft (20) being related to a torque flow (22) running from the rotor (16) to the output shaft (5), via which a torque (23) provided by the electric machine (15) via the rotor (16) for starting the internal combustion engine (2) can be transmitted from the rotor (16) to the output shaft (5), in the torque flow (22) between the rotor (16) and the output shaft (5) is arranged.

Description

The invention relates to a crank drive for an internal combustion engine of a motor vehicle according to the preamble of patent claim 1.

The WO 2005/111395 A2 discloses a motorcycle with an internal combustion engine, the internal combustion engine having an exhaust gas turbocharger, which is preferably arranged in the front region of the internal combustion engine, viewed in the direction of travel.

The object of the invention is to create a crank drive for an internal combustion engine of a motor vehicle, so that the installation space and costs of the internal combustion engine can be kept particularly low.

According to the invention, this object is achieved by a crank drive for an internal combustion engine of a motor vehicle with the features of patent claim 1 . Advantageous configurations of the invention are the subject matter of the dependent patent claims and the description.

The invention relates to a crank drive for an internal combustion engine of a motor vehicle, which is preferably designed as a motor cycle, in particular as a motorcycle. Alternatively, the motor vehicle can be designed as a motor vehicle, in particular as a passenger car, utility vehicle or truck.

The internal combustion engine has an intake duct through which air can flow and an exhaust duct through which exhaust gas from the internal combustion engine can flow. The internal combustion engine includes at least one combustion chamber. The air can be supplied to the combustion chamber via the intake tract, as a result of which the air can be introduced into the combustion chamber. The exhaust gas can be discharged from the combustion chamber via the exhaust tract. In a fired operation of the internal combustion engine, combustion processes take place in the combustion chamber, in which a fuel-air mixture is burned, resulting in the exhaust gas of the internal combustion engine.

In a fully manufactured state of the internal combustion engine, the internal combustion engine has the crank mechanism. The crank drive comprises an output shaft which can be rotated relative to a housing element of the internal combustion engine and via which the motor vehicle can be driven by the internal combustion engine. The output shaft is rotatable about an output shaft axis of rotation of the output shaft relative to the housing member. The output shaft is preferably designed as a crankshaft.

In an activated state of the internal combustion engine, the combustion processes take place in the combustion chamber. Preferably, in the activated state, the output shaft is rotated relative to the housing member. In a deactivated state of the internal combustion engine, the combustion processes in the combustion chamber do not take place. In the deactivated state, the output shaft is preferably stationary, which can be understood in particular as meaning that the output shaft is not rotated relative to the housing element. When starting the internal combustion engine, the internal combustion engine is switched from the deactivated state to the activated state. Starting can in particular be referred to as cranking or as activating.

The internal combustion engine comprises at least one electric machine having a rotor. The electrical machine can have a stator, the rotor being rotatable relative to the stator about a machine axis of rotation of the electrical machine. The rotor is thus rotatable relative to the housing member. Electrical power can be converted into mechanical power by means of the electrical machine, as a result of which the rotor can be driven and thus rotated relative to the stator. The electrical power can be taken from an on-board network of the motor vehicle, for example.

The output shaft can be driven via the rotor by means of the electrical machine in order to start the internal combustion engine. In other words, the rotor of the electrical machine and the output shaft are connected or can be connected to one another in a torque-transmitting manner, whereby a torque provided by the electrical machine via the rotor for starting the internal combustion engine can be transmitted from the rotor to the output shaft. The electrical machine can thus be referred to as a starter in particular. As a result of the drive of the output shaft by the rotor, the output shaft, which is stationary and thus in its rest position, can be accelerated and thus rotate at a speed greater than zero relative to the housing element about the output shaft axis of rotation, as a result of which the internal combustion engine can be started.

The internal combustion engine comprises at least one mass balance, which comprises at least one balancing element that can be driven by the output shaft and is therefore rotatable relative to the housing element, in particular mechanically coupled to the output shaft, for the purpose of, in particular, targeted balancing of inertial forces of the crank mechanism of the internal combustion engine having. In other words, the output shaft and the compensating element are connected to one another in a torque-transmitting manner, as a result of which a second torque can be transmitted from the output shaft to the compensating element in order to drive the compensating element, as a result of which the compensating element can be rotated relative to the housing element or can be kept rotating. The mass balance, in particular the balancing element, is provided for at least partial, in particular complete, balancing of free inertial forces of the crank drive or the internal combustion engine.

The compensating element is preferably designed as a compensating shaft. Alternatively, the compensating element can be designed as a compensating wheel. The balancer shaft can in particular be referred to as a mass balancer shaft.

The compensating element, in particular the compensating shaft or the compensating wheel, can be rotated about an axis of rotation of the compensating element relative to the housing element. The axis of rotation of the compensating element can be parallel to the axis of rotation of the output shaft. The axis of rotation of the compensating element is preferably spaced apart from the axis of rotation of the output shaft.

The targeted balancing of the mass forces can be understood in particular to mean that the balancing element was designed or designed during development or construction of the crank mechanism in such a way that the mass forces during operation of the internal combustion engine can be at least partially balanced by means of the balancing element as a result of the design.

In order to be able to keep the costs and installation space of the internal combustion engine or the crank mechanism particularly low, it is provided according to the invention that the compensating element, based on a torque flow running from the rotor to the output shaft, via which the torque provided by the electric machine via the rotor for starting the Internal combustion engine can be transmitted from the rotor to the output shaft, is arranged in the torque flow between the rotor and the output shaft. In other words, the compensating element is arranged between the rotor and the output shaft in relation to the flow of torque, as a result of which the torque can be transmitted from the rotor to the output shaft via the compensating element. In other words, the rotor, the compensating element and the output shaft are coupled to one another mechanically, in particular in a torque-transmitting manner, in such a way that the compensating element can be driven, in particular directly, by the rotor and the output shaft can be driven, in particular directly, by the compensating element driven by the rotor is.

The fact that the torque can be transmitted from the rotor to the output shaft can be understood in particular to mean that a torque of the output shaft caused or realized by the torque of the rotor as a result of the transmission and in particular referred to as output shaft torque can be different from the torque of the rotor. For example, at least one transmission can be provided between the rotor and the output shaft, as a result of which the output shaft torque can be different from the torque of the rotor. In other words, the rotor and the compensating element can be mechanically coupled to one another via the transmission.

The fact that the second torque can be transmitted from the output shaft to the compensating element can be understood in particular to mean that a torque of the compensating element that is caused or realized by the second torque of the output shaft as a result of the transmission and is referred to in particular as the compensating torque is different from the second torque of the output shaft can be. For example, at least one transmission can be provided between the output shaft and the compensating element, as a result of which the output shaft torque can be different from the torque of the rotor as a result of the transmission. In other words, the output shaft and the compensating element can be mechanically coupled to one another via the transmission.

The invention is based in particular on the following findings and considerations: In a conventional crank drive, the mass balance, in particular the balancing element, and the electric machine, in particular the rotor, can be installed separately from one another. This can in particular be understood to mean that in a conventional crank drive the compensating element is not arranged in the torque flow between the rotor and the output shaft in relation to the torque flow running from the rotor to the output shaft. As a result, the installation space and costs of a conventional crank drive can be particularly increased.

In contrast, in the case of the crank drive according to the invention, the torque flow running from the rotor to the output shaft runs over the balancing element. Thus, no torque flows that differ from one another are required for starting the internal combustion engine and for mass balancing. As a result, the installation space and costs of the crank drive or the internal combustion engine can be kept particularly low. For example, in the case of the crank drive according to the invention, an installation space is freed up which would be occupied by the compensating element if the compensating element were not arranged in the torque flow. As a result, a package advantage can be achieved for the crank mechanism or the internal combustion engine. As a result, the costs of the internal combustion engine or the crank mechanism can be kept particularly low.

Preferably, at least one gear stage is provided which has a gear ratio that differs from 1 and which, with respect to the torque flow, is arranged in the torque flow between the rotor and the compensating element. In other words, the crank mechanism has the gear stage, which is arranged between the rotor and the compensating element in relation to the torque flow running from the rotor to the output shaft, as a result of which the torque can be transmitted from the rotor to the compensating element via the gear stage. In other words, the rotor, the compensating element and the gear stage are mechanically coupled to one another in such a way that the gear stage can be driven by the rotor, with the compensating element being able to be driven by the gear stage driven by the rotor. The gear stage has the gear ratio, which has a value, referred to in particular as the gear ratio value, which is greater than or less than 1. 1, a respective torque value and a respective speed value of the rotor can be different from a respective torque value and a respective speed value of the compensating element. As a result, both the internal combustion engine can be started in a particularly advantageous manner and mass balancing can take place in a particularly advantageous manner.

The crank drive can have at least one gear element, it being possible for the gear element to comprise the gear stage. The gear stage or the gear element is preferably designed as a countershaft gear for the starter. Thus, the gear stage or the countershaft transmission is provided in particular to convert the torque provided by the electric machine via the rotor in such a way that the respective torque value transmitted to the output shaft is particularly suitable for starting the internal combustion engine. The countershaft transmission can in particular be referred to as a starter countershaft.

In a conventional crank drive, it is usually provided that the gear stage or the starter transmission is installed separately from the mass balance, in particular the balancing element. This can in particular be understood to mean that in the conventional crank drive the gear stage is not arranged in the torque flow between the rotor and the compensating element. In contrast, in the case of the crank drive according to the invention, the compensating element and the gear stage or the countershaft gear can be or be combined with one another. As a result, the number of parts in the internal combustion engine or in the crank mechanism can be kept particularly low. As a result, the costs and weight of the internal combustion engine or the crank mechanism can be kept particularly low. In addition, a package advantage of the crank mechanism or the internal combustion engine can be achieved.

In a further embodiment, it is provided that the compensating element is a shaft, in particular a transmission output shaft, of the transmission stage. In other words, the gear includes the compensating element or the balance shaft, which is preferably designed as a transmission output shaft of the gear. To put it another way, the balancer shaft is preferably designed as a shaft, in particular as a transmission output shaft, of the transmission stage. The balancer shaft or the mass balance is thus integrated into the gear stage or the countershaft transmission. The gear stage and the compensating element thus form a common assembly, by means of which both the translation and the mass balancing can be implemented. As a result, the variety of parts of the crank mechanism can be kept particularly low. The costs, installation space and weight of the internal combustion engine, in particular of the crank mechanism, can thus be kept particularly low.

In a further refinement, the gear stage has at least two wheels, one of the wheels, which can in particular be referred to as the first wheel, being non-rotatably connected to the compensating element, in particular the compensating shaft. In other words, the first wheel is arranged on the balancer shaft and is connected to the balancer shaft in a rotationally fixed manner, as a result of which the balancer shaft can be driven by the first wheel. The wheels are preferably in the form of spur gears or gears formed, which, in particular directly, mesh with each other.

Provision is preferably made for the other wheel, which can in particular be referred to as the second wheel, to be arranged in the torque flow between the rotor and the first wheel in relation to the torque flow. In other words, the rotor and the wheels are mechanically coupled to one another in such a way that the torque can be transmitted from the rotor via the wheels, in particular directly, to the balancing element, in particular the balancing shaft. In other words, the rotor can drive the first wheel, in particular directly, while the second wheel can be driven, in particular directly, via the first wheel driven by the rotor, and the balancing element, in particular the balancing shaft, by means of of the second wheel driven by the first wheel, in particular directly, can be driven. Thus, the torque can be particularly advantageously converted by the rotor by means of the gear stage and transmitted to the balancing element, in particular the balancing shaft, as a result of which the output shaft can be driven by the rotor in a particularly advantageous manner.

Provision is preferably made for a center of mass of the compensating element to be spaced apart in the radial direction of the compensating element from the axis of rotation of the compensating element, about which the compensating element can be rotated relative to the housing element. In other words, the compensating element has a targeted imbalance. As a result, the mass balancing of the crank drive or the internal combustion engine can be brought about in a targeted manner. As a result, vibrations of the crank mechanism or of the internal combustion engine can be kept particularly low. Thus, for example, the comfort of the internal combustion engine or of the motor vehicle can be particularly increased.

Targeted imbalance can be understood to mean the following in particular: Targeted imbalance is not a production-related or tolerance-related imbalance, rather the compensating element was designed during construction or development in such a way that the compensating element has the imbalance, by means of which the inertia forces are at least partially balanced as a result of the design can become.

For example, the compensating element can have at least one mass body, referred to in particular as a weight, which is spaced apart from the axis of rotation in the radial direction of the compensating element. This can cause the center of mass of the compensating element to be spaced apart from the axis of rotation in the radial direction of the compensating element. Alternatively or additionally, this can be brought about by the compensating element having at least one material recess, which is referred to in particular as a recess. If the compensating element has a plurality of mass bodies and/or material recesses, the mass bodies or material recesses are preferably arranged asymmetrically in relation to the axis of rotation of the compensating element.

In a further refinement, it is provided that mass forces of the second order of the crank mechanism or of the internal combustion engine can be at least partially, in particular predominantly or completely, compensated for by means of the mass balance, in particular by means of the balancing element. In other words, the mass balance is designed as a complete or partial second-order mass balance, in particular as a 50% second-order mass balance. For example, in the activated state of the internal combustion engine, a speed of the compensating element corresponds to twice the speed of the output shaft. This can in particular be understood to mean that while the internal combustion engine is in the activated state, the compensating element rotates at twice the speed of the output shaft. In this way, the second-order mass forces can be balanced. As a result, vibrations of the crank mechanism can be kept particularly low, as a result of which the comfort of the internal combustion engine or of the motor vehicle can be particularly increased.

In a further embodiment, at least one freewheel element, referred to in particular as a freewheel, is provided, which is arranged in the torque flow between the rotor and the compensating element in relation to the torque flow, with the rotor being coupled via the freewheel element to the compensating element, in particular mechanically, in such a way that the Torque can be transmitted from the rotor to the compensating element via the freewheeling element and the second torque, which runs opposite to the torque, is not transmitted from the compensating element or the output shaft via the freewheeling element to the rotor. In other words, the freewheeling element is arranged between the rotor and the compensating element in relation to the torque flow, the freewheeling element being designed in such a way that the output shaft can be driven by the rotor via the freewheeling element, whereas the rotor can be driven from the off same element cannot be driven via the freewheel element. The freewheeling element thus prevents the rotor from being driven by the compensating element or the output shaft. As a result, the compensating element can be permanently driven by the output shaft in the activated state of the internal combustion engine, as a result of which the mass balancing is carried out permanently in the activated state of the internal combustion engine. The electrical machine is designed as a starter and preferably not as a generator. That is, driving the rotor by the output shaft in the activated state of the internal combustion engine would cause additional frictional resistance. The freewheel element can ensure both the mass balance and the additional frictional resistance can be avoided or reduced. As a result, the fuel consumption of the internal combustion engine can be kept particularly low.

Provision is preferably made for the freewheel element to be arranged in relation to the torque flow in the torque flow between the gear stage, in particular the first wheel or the second wheel, and the compensating element, with the gear stage, in particular the first wheel or the second wheel, being connected to the compensation element is mechanically coupled, that the torque from the gear stage, in particular the first wheel or the second wheel, can be transmitted via the freewheel element to the compensation element and the transmission of the second torque, which runs counter to the torque flow, from the compensation element via the freewheel element to the gear stage , In particular the first wheel or the second wheel is omitted.

In a further embodiment, a clutch part of a clutch is provided, the motor vehicle being able to be driven by the internal combustion engine via the output shaft and via the clutch, in particular the clutch part. This can be understood in particular as follows: In its fully manufactured state, the motor vehicle has a drive train which includes the internal combustion engine, the motor vehicle being able to be driven by means of the drive train, in particular by means of the internal combustion engine. The drive train includes the clutch. The clutch is related to a second torque flow running from the output shaft of the internal combustion engine to at least one ground contact element, in particular a wheel, of the motor vehicle, via which a third torque provided by the output shaft for driving the ground contact element of the motor vehicle can be transmitted from the output shaft to the ground contact element is arranged in the third torque flow between the output shaft and the ground contact element. Preferably, based on the second torque flow, a transmission of the drive train, which is configured separately from the transmission element or the transmission stage, is arranged between the clutch and the ground contact element in the second torque flow. The motor vehicle or the drive train thus has the transmission in the fully manufactured state.

The output shaft can be coupled to the transmission and decoupled from the transmission by means of the clutch. Coupling the output shaft to the transmission means that the output shaft can be coupled to the transmission in a torque-transmitting manner, as a result of which, for example, the third torque provided by the output shaft can be transmitted to the transmission. As a result, the transmission can be driven, as a result of which the ground contact element of the motor vehicle can be driven via the transmission.

The clutch is preferably arranged between the output shaft and the transmission in relation to the second torque flow running from the output shaft to the transmission, via which the third torque can be transmitted from the output shaft to the transmission, so that the second torque flow, particularly when the Coupling is closed, runs over the clutch. The second torque flow can alternatively run in the opposite direction from the transmission to the output shaft via the clutch.

The clutch has the clutch part, which in particular can be referred to as the first clutch part. The clutch has a second clutch part. The first clutch part can be connected to the output shaft in a torque-transmitting manner, in particular in a torque-proof manner, and the second clutch part can be connected in a torque-proof manner to the transmission, in particular a transmission input shaft.

The clutch can be opened and closed, which means that the clutch can be switched between an open state and a closed state. In the open state, the output shaft is decoupled from the transmission, in particular the transmission input shaft. In the closed state, the output shaft is coupled to the transmission, in particular the transmission input shaft. In the open state, the two clutch parts of the clutch or the output shaft and the transmission, in particular the transmission input shaft, are decoupled from one another, so that example no torque or at most a first clutch torque that is greater than zero, in particular, can be transmitted between the two clutch parts or between the output shaft and the transmission, in particular the transmission input shaft. In the closed state, the two clutch parts are connected to one another in a torque-transmitting manner, in particular frictionally, in such a way that a second clutch torque that is greater than the first clutch torque can be transmitted between the clutch parts or between the output shaft and the transmission, in particular the transmission input shaft.

A non-rotatable connection can be understood in particular as a connection between two separately configured components that are connected to one another in such a way that at least relative rotations between the components and preferably in the axial direction and in the radial direction of the components relative movements between the components are suppressed or avoided.

In a further refinement, provision is made for the first clutch part to be arranged in the torque flow between the compensating element and the output shaft in relation to the torque flow. In other words, the first clutch part is arranged between the compensation element and the output shaft in relation to the torque flow, so that the torque can be transmitted from the rotor or the compensation element to the output shaft via the first clutch part and the second torque can be transmitted from the output shaft to the compensation element is. In other words, the compensating element, the output shaft and the first clutch part are mechanically coupled to one another in such a way that the first clutch part can be driven by the compensating element, the output shaft being able to be driven by the first clutch part driven by the compensating element and vice versa.

The compensating element and/or the output shaft are preferably each connected to the first clutch part in a torque-proof manner.

A first further aspect relates to an internal combustion engine for a motor vehicle with a crank drive according to the invention. A second further aspect relates to a drive train for a motor vehicle with an internal combustion engine which has a crank drive according to the invention. Advantages and advantageous configurations of the invention are to be regarded as advantages and advantageous configurations of the first additional aspect and/or the second additional aspect and vice versa.

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own.

• 1 eine schematische Seitenansicht eines Antriebsstrangs mit einem erfindungsgemäßen Kurbeltrieb; und
• 2 eine schematische Teilschnittansicht eines Antriebsstrangs mit einem erfindungsgemäßen Kurbeltrieb; und
• 3 eine schematische Teilschnittansicht eines erfindungsgemäßen Kurbeltriebs.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. Show it:

• 1 a schematic side view of a drive train with a crank mechanism according to the invention; and
• 2 a schematic partial sectional view of a drive train with a crank mechanism according to the invention; and
• 3 a schematic partial sectional view of a crank mechanism according to the invention.

Elements that are the same or have the same function are provided with the same reference symbols in the figures.

1 shows a drive train 1 of a motor vehicle in a schematic side view. The motor vehicle is preferably designed as a motorcycle, in particular as a motorcycle. The drive train 1 is provided for driving the motor vehicle. For this purpose, the drive train 1 has an internal combustion engine 2, by means of which the motor vehicle can be driven.

The internal combustion engine 2 comprises a crank mechanism 3 which has an output shaft 5 which can be rotated relative to a housing element 4 of the internal combustion engine 2 . The output shaft 5 is rotatable about an output shaft axis of rotation 6 of the output shaft 5 relative to the housing element 4 . The motor vehicle can be driven by the internal combustion engine 2 via the output shaft 5 .

The internal combustion engine 2 has at least one combustion chamber, an intake duct through which air can flow and an exhaust duct through which an exhaust gas of the internal combustion engine 2 can flow. The air flowing through the intake tract can be supplied to the combustion chamber via the intake tract. The exhaust gas of the internal combustion engine 2 can be discharged from the combustion chamber via the exhaust tract. The Combustion Engine 2 has at least one inlet valve, by means of which the supply of air into the combustion chamber can be controlled or adjusted. The internal combustion engine has at least one outlet valve, by means of which the discharge of the exhaust gas from the combustion chamber can be controlled or adjusted. The crank drive 3 has a camshaft which can rotate relative to the housing element 4 and which is mechanically coupled to the inlet valve and the outlet valve. The output shaft 5 is mechanically coupled to the camshaft via a timing chain 7 , as a result of which the camshaft can be driven by the output shaft 5 . As a result, the intake valve and the exhaust valve can be actuated via cams arranged on the camshaft.

When the internal combustion engine 2 is in an activated state, combustion processes take place in the combustion chamber, during which a fuel-air mixture is burned, resulting in the exhaust gas of the internal combustion engine 2 . The combustion chamber is partially delimited by a piston 8 of the internal combustion engine 2 , in particular of the crank mechanism 3 . in the in 1 shown embodiment, two pistons 8 are shown. Each of the pistons 8 is assigned to a combustion chamber of the internal combustion engine 2 . The internal combustion engine 2 in the exemplary embodiment thus comprises two combustion chambers. The respective piston 8 can be moved translationally relative to a respective combustion chamber wall delimiting the respective combustion chamber. The respective piston 8 is mechanically coupled to the output shaft 5 via a respective connecting rod 8a. The translational movement of the respective piston 8 can be converted into a rotational movement of the output shaft 5 by means of the respective connecting rod 8a, as a result of which the output shaft 5 can be driven by the pistons 8.

2 1 shows the drive train 1 in a schematic partial sectional view. The drive train 1 comprises a clutch 9 which comprises a first clutch part 10 and a second clutch part 11 . The first clutch part 10 can in particular be referred to as the primary wheel of the clutch 9 . The first clutch part 10 is connected to the output shaft 5 in a torque-transmitting manner, in particular in a torque-proof manner. At least one transmission 12 is arranged in the drive train 1 , the second clutch part 11 being connected in a rotationally fixed manner to a transmission input shaft 13 of the transmission 12 . The transmission 12 has a transmission output shaft 14, with the transmission 12 being able to convert the speed and torque of the transmission input shaft 13, as a result of which the transmission output shaft 14 can have a different speed and a different torque than the transmission input shaft 13. The transmission input shaft 13 and the transmission output shaft 14 are relative to the housing member 4 rotatable. When the clutch 9 is in a closed state, the output shaft 5 and the transmission input shaft 13 are mechanically coupled to one another in such a way that the transmission input shaft 13 can be driven by the internal combustion engine 2 via the output shaft 5 . In other words, the output shaft 5 and the transmission input shaft 13 are connected to one another in a torque-transmitting manner in the closed state of the clutch 9 . When the clutch 9 is in an open state, the transmission input shaft 13 cannot be driven by the output shaft 5 via the clutch 9 . Thus, the output shaft 5 and the transmission input shaft 13 are decoupled when the clutch 9 is in the open state, that is to say they are not coupled to one another in a torque-transmitting manner. The transmission output shaft 14 can be coupled or capable of being coupled in a torque-transmitting manner to at least one ground contact element, in particular a wheel, of the motor vehicle. Thus, when the clutch 9 is in the closed state, the motor vehicle or the ground contact element, in particular the wheel, of the motor vehicle can be driven by means of the internal combustion engine 2 via the output shaft 5, via the closed clutch 9, in particular the first and the second clutch part 10, 11, and via the Transmission 12, in particular the transmission input shaft 13 and the transmission output shaft 14, are driven.

When the internal combustion engine 2 is in a deactivated state, the combustion processes in the combustion chamber do not take place. The internal combustion engine 2 can transition from the deactivated state to the activated state and vice versa. The transition of the internal combustion engine 2 from the deactivated state to the activated state can be referred to as starting or cranking the internal combustion engine 2 in particular. The internal combustion engine 2 , in particular the crank drive 3 , has an electric machine 15 for this purpose. 3 shows the drive train 1, in particular the crank mechanism 3, in a schematic partial sectional view, in which the electric machine 15 is shown. The electrical machine 15 has a rotor 16 and a stator 17 . The rotor 16 can be rotated about a machine axis of rotation 18 relative to the stator 17 or the housing element 4 . The output shaft 5 for starting the internal combustion engine 2 can be driven via the rotor 16 by means of the electrical machine 15 .

The crank drive 3 has at least one mass balance 19 , in particular referred to as a mass balance device, which has at least one mass balance that can be driven by the output shaft 5 and is therefore rotatable relative to the housing element 4 bare with the output shaft 5 mechanically coupled compensating element 20 for targeted compensation of mass forces of the crank mechanism 3 or the internal combustion engine 2 includes. In the exemplary embodiment, the compensating element 20 is designed as a compensating shaft 20 . The mass balance 19, in particular the balance shaft 20, is thus provided for at least partial, in particular complete, balancing of free mass forces of the crank mechanism 3. The balancing shaft 20 is thus coupled to the output shaft 5 in a torque-transmitting manner. The balancer shaft 20 can be rotated about an axis of rotation 21 of the balancer shaft 20 , referred to in particular as the shaft axis of rotation 21 , relative to the housing element 4 .

The output shaft 5 preferably has a pinion 5a. The output shaft 5 for starting the internal combustion engine 2 can be driven by the rotor via the pinion 5a. The balancer shaft 20 can be driven by the output shaft 5 via the pinion 5a, in particular when the internal combustion engine 2 is in the activated state. A transmission between the output shaft 5 and the mass balancer 19 or the balancer shaft 20 can be implemented by means of the pinion 5a. As a result, in the activated state of internal combustion engine 2, a speed of output shaft 5 is different from a speed of balancer shaft 20.

In order to be able to keep the installation space and costs of the internal combustion engine 2 or the crank mechanism 3 particularly low, it is provided that the balancer shaft 20, based on a torque flow 22 running from the rotor 16 to the output shaft 5, via which a torque from the electric machine 15 via the Torque 23 provided by the rotor 16 for starting the internal combustion engine 2 can be transmitted from the rotor 16 to the output shaft 5 , in which the torque flow 22 is arranged between the rotor 16 and the output shaft 5 . In other words, the rotor 16 , the balancer shaft 20 and the output shaft 5 are mechanically coupled in such a way that the torque 23 can be transmitted from the rotor to the output shaft 5 via the balancer shaft 20 .

In a further refinement, at least one gear stage 25 is provided which has a gear ratio 24 that differs from 1 and which is arranged in the torque flow 22 between the rotor 16 and the balancer shaft 20 in relation to the torque flow 22 . The gear stage 25 is formed separately from the gear 12 and is spaced apart from the gear 12 . The gear stage 25 is preferably designed as a countershaft gear or as a gear stage 25 of the countershaft gear. The countershaft transmission can in particular be referred to as a starter countershaft. The torque 23 transmitted from the rotor 16 to the output shaft 5 can be converted by means of the gear stage 25, as a result of which the internal combustion engine 2 can be started particularly advantageously.

It is preferably provided that the balancing shaft 20 is a shaft 26 , in particular a transmission output shaft, of the transmission stage 25 . As a result, functions referred to in particular as torque conversion or speed conversion of the gear stage 25 and the mass balancing by means of the balance shaft 20 can be combined in a common assembly, the assembly comprising the gear stage 25, in particular the translation 24, and the balance shaft 20. In other words, the mass balance 19 and the starter transmission can be combined with one another. As a result, for example, the number of parts in the crank mechanism 3 can be kept particularly low. As a result, the costs, installation space and weight of the crank mechanism 3 or of the internal combustion engine 2 can be kept particularly low.

In a further refinement, it is provided that the gear stage 25 has two wheels 27, 28, one of the wheels 27 being able to be referred to in particular as the first wheel 27 and being connected to the balancer shaft 20 in a torque-proof manner. In this case, the first wheel 27 is preferably arranged on the balancer shaft 20 . The other wheel 28 can in particular be referred to as the second wheel 28 and is arranged in the torque flow 22 between the rotor 16 and the first wheel 27 in relation to the torque flow 22 . As a result, the torque 23 can be transmitted from the rotor 16 via the second wheel 28 and the first wheel 27 to the balancer shaft 20 for driving the balancer shaft 20 . The gears 27, 28 are gears, which in particular mesh directly with one another.

In a further embodiment, it is provided that a center of gravity 29 of the balancer shaft 20 is spaced apart from the axis of rotation 21 of the shaft in the radial direction 30 of the balancer shaft 20 . This can cause an imbalance in the balancing shaft 20, as a result of which the free inertia forces of the crank mechanism 3 can be balanced.

In a further embodiment, it is provided that mass forces of the second order of the crank drive 3 or of the internal combustion engine 2 can be compensated by means of the mass balance 19, in particular the balance shaft 20. As a result, vibrations of the crank mechanism 3 or of the internal combustion engine 2 can be particularly low be maintained, whereby a comfort of the internal combustion engine 2 or the motor vehicle can be particularly increased.

The pinion 5a is preferably designed in such a way that the speed of the balancer shaft 20 in the activated state of the internal combustion engine 2 is twice as high as the speed of the output shaft 5. In this way, the inertial forces of the second order can be at least partially, in particular predominantly or completely, balanced.

In a further embodiment, at least one freewheel element 31 is provided, which is arranged in the torque flow 22 between the rotor 16, in particular the first wheel 27, and the balancer shaft 20 in relation to the torque flow 22. The rotor 16, in particular the first wheel 27, is mechanically coupled to the balancer shaft 20 via the freewheel element 31 in such a way that the torque 23 can be transmitted from the rotor 16, in particular the first wheel 27, via the freewheel element 31 to the balancer shaft 20 and there is no transmission of a second torque 32 running in the opposite direction to the torque flow 22 from the balancer shaft 20 via the freewheel element 31 to the rotor 16, in particular the first wheel 27. In other words, the second torque 32, which can be provided by the output shaft 5 and is provided for driving the balancer shaft 20 through the output shaft 5 and runs in a second torque flow 33 opposite to the torque flow 22, cannot act on the rotor via the freewheel element 31 16, in particular the first wheel 27, are transmitted, whereas the freewheel element 31 allows the balancing shaft 20 to be driven by the rotor 16, in particular by the first wheel 27. This means that the rotor 16, in particular the wheels 27, 28, cannot be rotated or driven when the internal combustion engine 2 is in the activated state. As a result, for example, friction of the crank mechanism 3 can be kept particularly low, as a result of which the fuel consumption of the internal combustion engine 2 can be kept particularly low.

Provision is preferably made for the first clutch part 10 to be arranged in the torque flow 22 between the balancer shaft 20 and the output shaft 5 in relation to the torque flow 22 . In other words, the output shaft 5 can be driven by the rotor 16 via the first clutch part 10 in order to start the internal combustion engine 2 . In other words, the balancer shaft 20 can be driven by the output shaft 5 via the first clutch part 10 . As a result, the installation space of the crank drive 3 can be kept particularly small. The balancing shaft 20 and the output shaft 5 are preferably connected to the first clutch part 10 in a torque-proof manner. The balancing shaft 20 and the output shaft 5 are not connected to the second clutch part 11 in a rotationally fixed manner.

Reference List

1

powertrain

2

internal combustion engine

3

crank drive

4

housing element

5

output shaft

5a

pinion

6

output shaft axis of rotation

7

timing chain

8th

Pistons

8a

connecting rod

9

coupling

10

first clutch part

11

second clutch part

12

transmission

13

transmission input shaft

14

transmission output shaft

15

electric machine

16

rotor

17

stator

18

machine axis of rotation

19

mass balancing

20

compensation element

21

axis of rotation

22

torque flow

23

torque

24

translation

25

gear stage

26

Wave

27

first wheel

28

second wheel

29

center of mass

30

radial direction

31

freewheel element

32

second torque

33

second torque flow

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2005111395 A2 [0002]

Claims (10)

Crank mechanism (3) for an internal combustion engine (2) of a motor vehicle, with an output shaft (5) which can be rotated relative to a housing element (4) of the internal combustion engine (2) and via which the motor vehicle can be driven by the internal combustion engine (2), with a rotor (16) having an electrical machine (15), by means of which the output shaft (5) can be driven via the rotor (16) to start the internal combustion engine (2), and with a mass balance (19) which has at least one of the output shaft (5) compensating element (20) which can be driven and thus rotated relative to the housing element (4) for compensating for inertial forces of the crank mechanism (3). characterized in that the compensating element (20), in relation to a torque flow (22) running from the rotor (16) to the output shaft (5), via which a torque (23 ) for starting the internal combustion engine (2) from the rotor (16) to the output shaft (5) can be transmitted, is arranged in the torque flow (22) between the rotor (16) and the output shaft (5). Crank mechanism (3) after claim 1 characterized by at least one gear stage (25) having a ratio different from 1 (24), which is arranged in the torque flow (22) between the rotor (16) and the compensating element (20) in relation to the torque flow (22). Crank mechanism (3) after claim 2 , characterized in that the compensating element (20) is a shaft (26) of the gear stage (25). Crank mechanism (3) after claim 2 or 3 , characterized in that the gear stage (25) has two wheels (27, 28), one of the wheels (27) being non-rotatably connected to the compensating element (20). Crank mechanism (3) after claim 4 , characterized in that the other wheel (28) is arranged in relation to the torque flow (22) in the torque flow (22) between the rotor (16) and the one wheel (27). Crank drive (3) according to one of the preceding claims, characterized in that a center of mass (29) of the compensating element (20) is spaced in the radial direction (30) of the compensating element (20) from an axis of rotation (21) about which the compensating element (20 ) is rotatable relative to the housing element (4). Crank mechanism (3) according to one of the preceding claims, characterized in that mass forces of the second order of the crank mechanism (3) can be balanced by means of the mass balance (19). Crank mechanism (3) according to one of the preceding claims, characterized by a freewheeling element (31) which is arranged in relation to the torque flow (22) in the torque flow (22) between the rotor (16) and the compensating element (20), the rotor (16) is coupled to the compensating element (20) via the freewheel element (31) in such a way that the torque (23) can be transmitted from the rotor (16) to the compensating element (20) via the freewheel element (31) and a transmission of an opposite to the torque flow (22), second torque (32) from the compensating element (20) via the freewheeling element (31) to the rotor (16) is omitted. Crank drive (3) according to one of the preceding claims, characterized by a clutch part (10) of a clutch (9), the motor vehicle being able to be driven by the internal combustion engine (2) via the output shaft (5) and the clutch (9). Crank mechanism (3) after claim 9 , characterized in that the coupling part (10) is arranged in relation to the torque flow (22) in the torque flow (22) between the compensating element (20) and the output shaft (5).

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