Block-like Electric Drive Providing Dual Single-wheel Drives with Parking Locks
A block-like electric drive providing two single-wheel drives on one axle comprises two electric machines, each having a parallel rotor axis and a transmission on an end face. The single-wheel drives or the electric machines are arranged at least partially congruent with each other in a longitudinal vehicle direction for installation. A respective inverter serves to actuate each one of the two electric machines, the inverters being arranged next to each other at a highest point of the drive block in the installation position. The two electric machines are arranged one behind the other with regard to their housings. The drive block thus has two drives with separate transmission housings. Each drive can advantageously be equipped with a parking lock for blocking an output shaft. A locked state can thus be created in each drive combination.
The present invention relates to a drive block of an electric vehicle that includes one or two parking locks.
The present invention additionally relates to a drive block of an electric vehicle that provides two single-wheel drives and parking locks that can be operated via a parking lock actuation mechanism.
BACKGROUNDOf particular interest are drive trains by which electric single-wheel drives can be implemented. These so-called single-wheel electric drives offer the possibility of electric “torque vectoring”. With regard to the arrangement of their components and their mechanisms of action, paired single-wheel electric drives can be implemented in various ways.
Some single-wheel drives are constructed using wheel hub motors, as described, inter alia, in DE 10 2014 214 821 A1 (applicant: Schaeffler Technologies GmbH & Co. KG). In drive concepts using wheel hub motors, the developers require installation space at each drive wheel because the motor, the transmission and possibly other components of the drive have to be installed directly next to the drive wheel, as can also be seen from the two figures of DE 10 2014 214 821 A1.
Therefore, when using electric drives to replace internal combustion engines in fully developed motor vehicles, it is in many cases easier to provide block-like and centrally arranged drive units at the position where the internal combustion engine and its components and add-on parts were formerly located.
On the one hand, single-wheel drives which are consolidated into blocks are known, in the case of which each one of two motors can drive one of the two wheels on an axle of a motor vehicle via a joint twin transmission, which is the connecting intermediate component that forms the block, as described, for example, in German utility models DE 20 2019 103 770 U1 (proprietor: hofer powertrain innovation GmbH), DE 20 2019 103 771 U1 (proprietor: hofer powertrain innovation GmbH), DE 20 2019 103 778 U1 (proprietor: hofer powertrain innovation GmbH), DE 20 2019 103 779 U1 (proprietor: hofer powertrain innovation GmbH) and DE 20 2019 103 781 U1 (proprietor: hofer powertrain innovation GmbH).
On the other hand, there is the concept of arranging two separate motors in a manner at least partially overlapping each other in the vehicle longitudinal axis, and providing on the end face of each a dedicated transmission, separate from the other transmission, for reducing the motor speed to a wheel speed, as disclosed, for example, in WO 2017/211 793 A1 (applicant: Punch Powertrain N.V.), in DE 10 2010 010 438 A1 (applicant: Dr. Ing. h.c. F. Porsche AG) or also in EP 3 587 157 A1 (applicant: hofer powertrain innovation GmbH).
While WO 2017/211 793 A1 and DE 10 2010 010 438 A1 still assume that a motor on a motor vehicle axle can only be used to drive one wheel, EP 3 587 157 A1 discloses that the two motors, arranged axially one behind the other and laterally bordered by transmissions, can also be arranged in such a way that optionally one motor drives two wheels on one common axle, but a single-wheel drive is also possible with such an arrangement.
For such arrangements of single-wheel drives to form a drive block, which is also referred to as a “sandwich design” due to being laterally bordered by the transmissions, a problem in terms of installation space often arises, particularly in the case of more compact vehicles or in the case of sports cars.
DE 10 2014 214 821 A1 (applicant: Schaeffler Technologies GmbH & Co. KG) describes a wheel hub drive with two electric motors on a rear axle. At the end of the description, the specification considers how such a single-wheel drive device can additionally be equipped to brake the wheel drive device. In said document, a disk brake, a drum brake and a parking lock are mentioned as possibilities for braking a vehicle equipped with such single-wheel drive devices.
A single-wheel drive with a brake is discussed in DE 10 2010 007 066 A1 (applicant: Rheinmetall Landsysteme GmbH), which describes, inter alia, an axle component for an armored wheeled vehicle that can be assembled from a plurality of vehicle modules. As shown in
FIGS. 1 and 2 of US 2019/061 504 A1 (applicant: NIO USA, Inc.) show motor vehicles which are equipped with single-wheel drives.
Patent application DE 10 2018 103 483 A1 (applicant: Toyoto Jidosha Kabushiki Kaisha) relates to providing a drive force control system for a drive arrangement comprising two electric motors, which are each said to drive one wheel. The aim of the control is to keep the slip of the wheels as low as possible. The control is also said to take into consideration a drive force transmitting capacity of a clutch that serves to operate the first motor and the second motor as a connected unit. The control is said to be accomplished by a control unit using situation-related maps for particular drive situations, such as e.g. in the case of cornering, and using a torque sensor and a yaw rate sensor. There is said to be one parking lock on a front axle and one parking lock on a rear axle, which parking locks are said to be suitable for stopping either a rotation of a second output shaft or a rotation of a first countershaft.
Patent EP 2 406 111 B1 (proprietor: Nissan Motor Co. Ltd.) describes a parking lock device, with which it is said to ensure the parking lock device cannot be activated while the vehicle is traveling. This is said to be achieved by limiting the force for the actuator, which presses a pawl against a parking lock gear. In addition, in order to protect a right parking lock and to protect a left parking lock, a rotation of a right wheel and a rotation of a left wheel are said to be monitored separately by sensors.
EP 2 719 591 A1 (Applicant: Nissan Motor Co., Ltd.) mainly deals with the control of parking locks. If a vehicle is still moving, i.e. is not absolutely stationary, it is provided that, in addition to a first parking lock mechanism, a second parking lock mechanism will also be activated, which is said to be located on a different wheel. By contrast, if a vehicle is completely stationary, the activation of a single parking lock mechanism is deemed to be sufficient, thus making it possible to save energy involved in actuating the parking lock. The vehicle is said to be driven via wheel hub motors on rear wheels of the vehicle, as shown in
DE 10 2011 080 236 A1 (applicant: ZF Friedrichshafen AG) relates to a single-wheel electric motor drive for a motor vehicle, which is referred to as being close to the wheel. With reference to eight drawings, which are numbered from 1 to 7, six different placements of a parking lock on a single-wheel drive are proposed using line drawings.
Patent application JP 2009-120 126 A (applicant: Mazda Motor Corp.) shows in
The documents mentioned above are hereby incorporated by reference in their entireties. This is to avoid having to explain anew the well-known relationships between single-wheel drives and the structural arrangement of the individual components; instead, through reference to the documents, these relationships are to be regarded as likewise defined for the present invention.
SUMMARYAs stated, the development of an electric drive train comprising two single-wheel drives provided by two separate motors or electric machines leads to increased requirements in terms of the necessary installation space. At the same time, however, the desire for reliable, safe drives, which ideally have safety features already built in, cannot be ignored.
The question therefore arises as to how it is possible to realize the attractiveness of electric motor-driven single-wheel drives in tight installation spaces and yet still be able to give consideration to special safety requirements.
Motor vehicles that are to be driven by an electric motor require at least one electric machine, such as e.g. a synchronous machine or e.g. an asynchronous machine or further developments derived from these basic types of electric machine (reluctance motor, wheel hub motor, canned motor, resistance rotor, Ferraris' motor, etc.). Usually a motor that rotates at a speed higher than a wheel speed is used as the drive motor in a passenger car, the speed of the motor being reduced to an (appropriate) wheel speed, e.g. in a speed range between 0 rpm to less than 2000 rpm, or in an alternative embodiment up to a maximum speed of approx. 2600 rpm, by a transmission situated on the output shaft of the motor.
If each wheel on an axle of a motor vehicle can be driven by a separate motor, this can be referred to as a single-wheel drive; however, there are also transmission arrangements—as is known or see above—by which (optionally or depending on a switch position) one of the motors or even both motors can be switched as axle drives instead of single-wheel drives. Advantageously, such a drive block comprising two electric machines, i.e. a first electric machine and a second electric machine, either drives one complete axle of a motor vehicle, or each electric machine drives one single road wheel on the axle of the motor vehicle that is to be driven. As stated, switchable hybrid forms can also be present on an axle of a motor vehicle, which, depending on the switching state, e.g. of a switchable differential, can be used either as a single-wheel drive or as an axle drive. If each electric machine drives one road wheel of the motor vehicle, “torque vectoring” (yaw angle control of the motor vehicle) can be operated through actuation of the electric machines, e.g. via an inverter, in particular by frequency control.
It is particularly advantageous if the individual components of one (sub-)drive can be pushed into the identical components of a second (sub-)drive, i.e. are arranged so as to move toward each other, which can also be referred to by the words “nestingly arranged”. In this case, it is possible to equip each (sub)-drive separately with all the components for driving a single wheel or even for driving a motor vehicle axle.
If the individual components of the drive block can be arranged in a compact block, then it is possible (in theory) to tailor the drive block, in terms of its dimensions, to the dimensions and shape of an internal combustion engine together with the units arranged thereon. The form factor corresponds (substantially) to an internal combustion engine together with its add-on units and, where applicable, its encapsulation. Such motors can be installed in a longitudinal vehicle direction, e.g. in an engine compartment beneath a hood. Here, the drive block can be provided for transverse installation in a motor vehicle. A transverse installation of the drive block can refer to an orientation in which the wheel drive shafts projecting out of the block are directed toward the wheels to be driven; there is no deflection through 90° to pass from the wheel drive shafts to the wheels on the axle.
If the maximum dimensions of the drive block correspond to the widths, heights and/or lengths of an internal combustion engine designed to drive a motor vehicle, it is possible to continue using a fully developed body and to insert the drive block as a replacement for a drive comprising an internal combustion engine. The installation space provided for an internal combustion engine can be used or occupied by the drive block. Other components that may usually be installed in the engine compartment, such as an auxiliary steering and/or steering assistance system, can remain unchanged in the engine compartment.
If the first electric machine drives a first single wheel, a first (reduction) transmission is required due to the higher speed of the electric machine and/or the angular velocity, which is too high for a wheel drive. If a second electric machine drives a second single wheel, a second (reduction) transmission is required due to the higher speed of the electric machine compared to the road wheel. If the transmissions are respectively attached to an end face of the first electric machine and to an end face of the second electric machine, this results in a (sub-)block consisting of one electric machine and an associated transmission. If the two electric machines are arranged in parallel with regard to their longitudinal extent, e.g. with regard to their rotor axes or their rotating axes, and one behind the other with regard to their housing, this results in a block composed of two L-shaped motor/transmission units.
The transmissions, that is to say the first transmission and the second transmission, can be implemented by a plurality of spur gear stages or also by a planetary transmission. Of course, it is also possible to implement one stage as a planetary transmission and another stage as a spur gear stage.
If the electric machines are motors which are operated with an AC voltage, either single-phase or multi-phase, such as e.g. three-phase, then at least one inverter is required as a further component of the drive block; preferably, however, two inverters are used, one inverter per drive formed of the electric machine and the transmission. The two inverters are advantageously placed onto the double L-shaped block formed of two electric machines and two transmissions situated at the cylindrical ends of the housings of the electric machines. In this case, the drive block is intended for an installation in which ideally the electric machines and the transmissions are placed in a lower area, while the inverters are arranged above the drive shafts of the electric machines, i.e. facing away from the ground. In the installation position (when the drive block has been oriented for installation in a motor vehicle (marriage with the chassis)), the heavier electric machines form the base of the drive block. The lighter inverters, which are often thermally more sensitive and in some cases also mechanically more fragile, are located in an area which, compared to the electric machines, is more remote from the ground.
Each drive combination, composed of an inverter, an electric machine and a transmission, constitutes a separate drive. The drive has a parking lock. The parking lock is responsible only for this one drive. Each drive (or sub-drive) is equipped with a separate parking lock for blocking an output shaft that leads out from the drive to a wheel.
The parking lock actuators are preferably placed in an area of the drive block close to the ground. Within the drive block, the parking lock actuators are situated in an area facing toward the ground. In other words, the parking lock actuators can advantageously be situated in a lower area of the drive block. The parking locks can be situated between the transmissions arranged on the output side, in particular in an area close to the ground.
The parking locks are there to enter a locked state when the drive, and thus the vehicle, is to be prevented from rolling away.
In a first, advantageous embodiment, the drive block includes two actuators, which are each there to actuate a separate parking lock per (sub-)drive.
In an alternative embodiment, instead of two parking lock actuators, it may also be provided that just one parking lock actuator can actuate both parking locks synchronously or simultaneously, i.e. at the same point in time.
The parking lock actuation mechanism, either one common actuator or a plurality of separate actuators, can be seated between the transmission housings.
It has proven to be advantageous if at least one of the inverters is a shallow box or, particularly in the case of a drive block constructed with two electric machines, more preferably both inverters are shallow boxes, which may for example be square. Each box can be dimensioned such that it forms approximately half of an upper side of the drive block. The first box, i.e. the first inverter, covers e.g. the right-hand side of the two electric machines arranged one behind the other, as a shallow unit spanning the latter. The second inverter can be arranged next to the first inverter. The second inverter can also cover both electric machines from above. The second inverter ideally has the same dimensions as the first inverter. The two inverters form the upwardly bounding cover with their upper housing shells.
Presented below are advantageous embodiments and developments which, considered per se, both individually and in combination, may likewise disclose inventive aspects.
The locked state can be brought about by inhibiting rotation. The inhibition of rotation can be accomplished in the transmission. Each transmission has its own parking lock.
Advantageously, each of the parking locks is designed such that, in a locked state, it rotationally immobilizes a planetary gear stage of the transmission by engaging in a planet carrier. In the locked state, the respective parking lock inhibits rotation.
It is possible for the parking lock to act at different points.
In one embodiment, the parking lock immobilizes an output gear.
In one embodiment, the parking lock immobilizes an input shaft of the transmission.
In one embodiment, the parking lock blocks the smaller pinion of two pinions that form a transmission stage.
In one embodiment, the parking lock immobilizes an output gear of the geared transmission stage. Even at this point, it is sufficient if a torque of less than e.g. 3000 Nm can be blocked, such as e.g. 2200 Nm.
The respective parking lock can be realized as a parking lock that is to be actuated hydraulically through its actuator. It is also possible that the parking lock operates through its actuator as a parking lock that is actuated by an electric motor.
One advantageous embodiment is a pawl-type lock, i.e. a parking lock which can be placed in its immobilized or locked state by virtue of a pawl.
It is also advantageous if the parking lock has an energy store, e.g. in the form of a strong annular spring, for releasing the parking lock. Alternative possibilities are offered by compression springs, conical springs or barrel springs.
Advantageously, a pawl of the pawl-type lock engages in a ring gear of a planetary transmission. The planetary transmission may have a ring gear connected (by a plug-in connection, welded, riveted or the like) to its output side, e.g. to the planet carrier, which ring gear performs the task of a locking gear. The transmission can be immobilized by the engaging pawl. To this end, external teeth may be present on the ring gear, e.g. in the form of a toothed outer rim. The ring gear is an additional component beside the planetary transmission.
The transmission has pinions of different sizes. Advantageously, a smaller of the pinions available in the transmission is selected to inhibit motion in the smaller pinion when a parking lock is engaged.
In one development, the transmission can be composed of a planetary transmission stage and a geared transmission stage, with one stage following the other stage. The two transmission stages are arranged in a row one after the other.
Both transmission stages have ratios to reduce the speed.
The drive block can be locked by pawls, which are mounted on dowel pins. The pawls are located on dowel pins, e.g. on pins which are less than 15 mm thick, e.g. just 10 mm thick. Such a dowel pin can be very short, e.g. less than 70 mm. It is thus possible to fit the entire parking lock, together with its actuator, in the tight installation space.
The parking locks may be rod-controlled. Rod control enables the parking lock actuator to be arranged at a different location than the parking lock (itself).
One of the transmissions may comprise multiple transmission stages (but it is also possible for both transmissions to comprise multiple transmission stages), e.g. two transmission stages, of which one transmission stage is a planetary transmission and one transmission stage is a geared transmission. Both transmission stages reduce the rotational speed or the number of revolutions; they are speed-reducing transmissions with a ratio in the range from 50 to 100.
The combinations and exemplary embodiments presented above can also be considered in numerous other connections and combinations.
A drive block of an electric motor-driven motor vehicle drive for two single-wheel drives on one axle has two electric machines, each having a parallel rotor axis and each having a transmission on an end face. The single-wheel drives or the electric machines are arranged at least partially congruent with each other for installation in a longitudinal vehicle direction. A respective inverter serves to actuate each one of the two electric machines, the inverters being arranged next to each other at a highest point of the drive block in the installation position. At least one of the inverters is designed as a shallow, almost square box such that it covers approximately one half of an upper side of the drive block. The two electric machines are arranged one behind the other with regard to their housings. The drive block thus has two drives with separate transmission housings. Each drive can advantageously be equipped with a parking lock for blocking an output shaft. A locked state can thus be created in each drive combination. The electric machines are intended for installation in a motor vehicle transverse direction. A parking lock actuation mechanism is seated between the transmissions in an area close to the ground.
For instance, it is possible, inter alia, to design the transmission housing and the electric machine housing as an overall housing. In this case, a first component is the electric motor-driven drive consisting of the electric machine and the transmission. A second or further component is the associated inverter.
The pawl-type lock can operate either with or without springs. A spring can be part of the lever mechanism to facilitate release of the pawl-type lock.
Further interesting aspects of a drive block outlined above will be set out below.
The underside of an inverter may be designed to be arranged on a support plate. The support plate may be a flat cover plate which forms the bridge element across the two electric machines. The support plate rests as a flat cover plate on the two electric machines. Vibrations of the electric machines or of the drive block are lessened if the support plate is sufficiently robust and at the same time is mounted in a manner that is advantageous in terms of vibration, so that the electronics of the inverter or both electronics of both inverters are subjected only to reduced oscillations and vibrations (ideally none at all).
In one advantageous embodiment, a cable connection adapter may be provided for each inverter. In one advantageous development, the two cable connection adapters differ from each other, with each cable connection adapter being designed for connection to one inverter. A cable connection adapter leads to an electrical connection of the inverter, to which the cable connection adapter is attached.
Incidentally, the components mentioned above, such as the first electric machine, the second electric machine, the first transmission, the second transmission, the first inverter and the second inverter, may in each case be designed as identical parts. It can also be said that the electric machines are designed as standard parts. Similarly, it can also be said that the transmissions are designed as standard parts. It can also be said that the inverters are standard parts. In one advantageous development, the cable connection adapters differ from this and distinguish whether the first (sub-)drive block is a left or a right (sub-)drive block and whether the second (sub-)drive block is a right or a left (sub-)drive block.
Such a cable connection adapter may be designed to be placed on the side of the inverter. The cable connection adapter determines where a connector is positioned laterally in relation to the inverter. As mentioned above, the inverter has a shape that is shallow but covers a (certain) length and a (certain) width. The inverter thus has a longitudinal extent or a width that ideally corresponds (substantially) to the width of the two electric machines arranged next to each other and/or offset from each other—in the sense of an overall width. The cable connection adapter therefore has a width that corresponds to the width of the two electric machines or, in the case of cylindrical housings of the electric machines, to the diameters of the electric machines when these are located fully next to each other.
Advantageously, the cable connection adapter is intended to make it possible for a power supply cable, which establishes an electrical connection from an electrical energy store, e.g. a lithium-ion battery pack, to the inverter via the cable connection adapter, to be connected by means of a connector, so that the inverter can be supplied with electrical energy from the electrical energy store.
A cable connection adapter can also be referred to as an electrical transmission means (energy supply point). Each inverter has its own cable connection adapter, it being possible for the cable connection adapter of the first inverter to differ from the cable connection adapter of the second inverter in terms of their specific designs. The connector positioning, which is present at a point on the longitudinal extent of the cable connection adapter, is advantageously placed between the energy store or a central energy source and the input of the inverter, an electrical connection of the inverter, in order to form an overall length. Advantageously, the motor vehicle has a single central energy source as the energy store.
In this way, a current path length can be defined. The current path length results from the length of a connection cable between the energy store and the connector positioning of the cable connection adapter as well as a cable routing within the cable connection adapter. If, due to cable routing within the motor vehicle, the length of a power supply cable on one of the cable connection adapters is shorter than the length of a cable on the other cable connection adapters, then the (total) length, the inductance, the resistance and/or the signal propagation times on the electrical connections between the energy store and the drive block can be equalized through cable routing within the cable connection adapter. Different lengths of the different connection cables can thus be equalized.
It is advantageous if a cable connection adapter (plug-in type) does not have just one position or one connector into which a mating connector of a power supply cable can be inserted, but instead a cable connection adapter offers a movable connector position or a plurality of connectors. One of the plurality of connectors can then be selected, depending on the cable routing or the length of the power supply cable. If the cable connection adapter offers a plurality of connector positions, a connection cable can be connected to any one of the available connector positions. The connectors or connector positions can be designed in such a way that a connection cable can optionally be connected to one or another position or to one or another connector.
The transmission housing is advantageously an elliptical housing or a shallow, elongated housing modeled on an elliptical shape, which is additionally situated at an angle (in relation to the ground or a road). If the two electric machines are situated (slightly) offset from each other (with regard to a base height), an additional length of installation space required for the transmission can be created by placing the transmission housing at an angle. In the case of an elliptical transmission housing, one of the foci of the ellipse, which is formed by a freewheel of the housing, may be an exit point for a wheel output shaft. A wheel output shaft exits from the transmission housing in the region of the focus. In this context, a focus is understood to be a design aid when forming the ellipse (according to conventional ellipse geometry). An ellipse (usually) has two foci and a center, as well as associated semi-axes. One of the foci is used as an exit point from the housing. One of the foci can be used as an entry point for a drive shaft of the electric machine. Drive power is introduced into the transmission at one focus, and drive power is output from the transmission at the other focus.
Each transmission advantageously has its own housing, i.e. the transmission housing associated with the transmission. Each transmission comprises a transmission housing. A transmission is equipped with a transmission housing.
The transmission housings extend further in the downward direction than the electric machines. A transmission, more precisely a transmission housing, is to be found in the region of a lowest point of the drive block. The transmission housing extends further into an area closer to the ground than either of the electric machines. The electric machines likewise have a lowest point. However, this lowest point is further away from the ground or the road than the lowest point of one of the transmission housings.
Advantageously, the transmissions flank, with their lower ends, an installation space that extends parallel to the electric machines between the transmissions. The electric machines can be bordered by further components from the underside. The electric machines are located in a central area. The installation space bordered laterally by the transmission housings is bounded in the upward direction by the electric machines.
The uppermost side of the drive block may be equipped with cooling fins. If the inverters are the highest components of the drive block, the cooling fins are located on the inverters. While electric machines are often not only mechanically more robust than inverters, but also can be much more easily designed for higher operating temperatures, many electronic components that have to be installed in an inverter encapsulated by a housing are thermally more sensitive, or the components have only a lower maximum operating temperature. If the cooling fins are situated on the upper side of the drive block, the temperature of the inverters can be lowered by air convection, e.g. by means of a motor vehicle fan (for example a viscous fan or another clutch fan).
In one advantageous embodiment, which is particularly compact, the component combination of electric machine and transmission is reminiscent of the capital letter “L”; the arrangement of the two components “electric machine” and “transmission” relative to each other can also be referred to as L-shaped. The inverter is reminiscent of a block. Identical inverters, as a first inverter and as a second inverter, can be part of the drive block if one of the two inverters has been rotated about its vertical housing axis relative to the other inverter and thus the two inverters are situated as a mirror image with respect to each other (in particular relative to a mirror symmetry point). Ideally, the two housings of the inverters are arranged at a small distance from each other, so that a separation gap is formed between the housings of the inverters. The point for the point-symmetrical mirror imaging of one inverter relative to the other inverter can be placed in the middle of this separation gap.
It is particularly advantageous to place the inverters on damping attachment points, e.g. on damping bearings. The inverters can be part of the drive block and yet be vibrationally decoupled from the rotating electric machines. A damping suspension ensures that each inverter stays in place.
If the individual (sub-)drive blocks are compared with each other, each (sub-)drive block has its own electrical connection, ideally its own cooling circuit inlet, ideally its own cooling circuit outlet, and ideally attachment points that can be found as a mirror image on the other (sub-)drive block. The components of the drive block are thus associated with each other. The two (sub-)drive blocks are designed such that, when pushed together, they form an overall block which, in terms of its dimensions, corresponds to a (conventional) internal combustion engine of a motor vehicle, in particular a small motor vehicle.
The drive units discussed above, which are assembled from two single-wheel drives in a block-like manner, can also be described as follows.
The drive block is advantageously designed such that each driven road wheel can be supplied with torque from a separate electric machine. A drive is said to be a separate drive, in particular of a single road wheel, if the electric machines provided for moving the vehicle can be individually supplied with a preferably different drive power from an electrical energy store, either using an inverter or without inverter.
To provide a required torque for a road wheel, a rotation of the electric machine is stepped down in each case in a transmission arranged in the torque flow between the electric motor and the road wheel.
The drive block is designed to be space-efficient and as compact as possible for installation in a motor vehicle.
The motor vehicle has a longitudinal vehicle direction which extends from a front wheel of the vehicle to a rear wheel of the vehicle (and runs beyond these). Without preference for one orientation or the other, the longitudinal vehicle direction can extend from the front of the vehicle to the rear of the vehicle or from the rear of the vehicle to the front of the vehicle, depending on which direction of travel is being considered. To form design aids, a vehicle longitudinal axis and/or a vehicle transverse axis can be “placed” centrally in the vehicle along a longitudinal vehicle direction, which can also be referred to as the vehicle longitudinal direction, and aligned with a transverse vehicle direction, which intersects the longitudinal vehicle direction and can also be referred to as the vehicle transverse direction. The design aids provide references for arranging the components of the (sub-)drive. In the case of transverse installation in the vehicle, a transmission shaft for example, such as the transmission input shaft and/or the transmission output shaft, extends along a vehicle transverse axis. Ideally, a vehicle longitudinal direction is to be situated as extending at right angles to a vehicle transverse direction. Examples of vehicle components which are usually installed in a motor vehicle transverse direction are motor vehicle axles, as well as steering linkages. The vehicle longitudinal axis and the vehicle transverse axis, which in particular intersect each other, span a plane as a (further) design aid, which in the vehicle separates a half-space close to the ground from a half-space remote from the ground. Extending perpendicularly to the plane is an (imaginary) vertical axis of the vehicle, which is directed both toward the ground and toward the sky. One part on the axis (vehicle vertical axis) can be referred to as an area close to the ground, which is situated below an area less close to the ground or below an area more remote from the ground. These location specifications “area close to the ground”, “area remote from the ground”, “vehicle vertical axis”, “vehicle longitudinal axis” and “vehicle transverse axis”, can be used to specify a geometric placement of a smaller component, such as a parking lock and/or a parking lock actuation mechanism, in a larger entity, such as the drive block or the vehicle. The axes, planes and areas serve as a design aid here.
A parking lock actuation mechanism serves to actuate at least one of the parking locks. In one embodiment, this actuation mechanism can be actuated manually, in an extremely energy-efficient manner, via a selector lever as a first component of the actuation mechanism. However, the parking lock actuator as the power source of the actuation mechanism may also comprise a direct current motor or a hydraulic or pneumatically movable piston/cylinder arrangement. If there is a power source, the selector lever can be implemented purely as a trigger button. However, the selector lever may introduce a portion of the actuation energy, while the power source supplies a further portion of the actuation energy for the parking lock actuator. A direct current motor (DC motor) can be integrated in a purely electrically powered vehicle using few additional components. An inverter downstream of the power store is not necessary. A DC motor that can draw at least some of its energy from an additional electrical capacity or from an additional power store is particularly advantageous.
Following a failure in the power supply to the drive system, below a suitable threshold speed in the rotation of the DC motor, the parking lock can automatically move into a locked position, particularly in cases where a sufficient store of energy is available.
The parking lock actuation mechanism comprises at least one, preferably exactly two, parking lock actuators. One component of a parking lock actuation mechanism may be a parking lock pawl or a locking pawl, a locking lever, a locking pin or a detent.
If a pawl is present as the locking element, this pawl has an engagement region which, at a receiving region that has a shape complementary to the engagement region, such as at a tooth, at a tooth gap, at a claw or at a gap in the claw, can block a rotational movement in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation. These directions correspond to a forward and backward rolling direction of a vehicle.
The engagement region and the receiving region are equipped with at least two locking flanks, which are preferably shaped in a manner complementary to each other. A locked state of the parking lock exists when the pawl is in an engaged position. A connection between a rotatable transmission component and a non-rotatable transmission component can thus be established via the pawl, so that the rotational degree of freedom that exists in the unlocked position is lost as a result of the locking action. The receiving region may be formed, for example, on a detent plate or on a parking lock gear.
In one embodiment, the parking lock engages in the course of a rotation of the rotatable transmission component. A pressing mechanism can comprise an elastically extensible component of the parking lock actuation mechanism.
If a pawl is present, the pawl thus moves into a latching position.
One example of a pressing mechanism is a roller rotatably mounted relative to the transmission housing on a spiral spring, which can also be referred to as a pressure spring. The roller can be brought to bear against a spine of the locking element, e.g. the pawl, by means of a selector lever and/or an actuating linkage of the actuation mechanism. The parking lock actuation mechanism may thus comprise multiple components which, individually and/or in combination, improve the function of the parking lock.
One component of a parking lock actuation mechanism may be a dowel pin, about which the locking element, e.g. the pawl, is pivotably mounted. By way of a relative movement, such as a rotation of the pawl, the engagement region of the pawl can be moved in a radial direction toward the receiving region, as a result of which the locked state can be established. Forces that act on the locking flanks in the receiving region can be diverted via the dowel pin to the transmission housing, in particular without the pawl changing its position.
Release of the parking lock, e.g. in a manner triggered via the selector lever, is brought about by pivoting the pawl in a relative movement, as a result of which a gap is created between the engagement region and the receiving region, in particular in a radial direction. In one advantageous development, the pawl is pivoted back as far as a stop, with a rotatability of the transmission being retained. The stop ensures that the pawl only has to travel a short distance before it engages.
As a component or module of the parking lock actuation mechanism, an actuating linkage can comprise a number of components, such as at least one of the following components: at least one push rod, at least one joint, at least one deflection lever, at least one turntable, at least one stop, at least one guide, or at least one spring, such as a return spring, a pressure spring or a compensating spring.
Preferably, the actuating linkage includes at least two such components, in particular in pairs. The actuating linkage establishes a connection, preferably a form-fitting connection, between at least one locking flank (or also two locking flanks) and the selector lever or the parking lock actuator.
A flank slope in the region of one locking flank may, in collaboration with a compensating spring for example, prevent the parking lock from engaging if the speed of a vehicle is greater than a threshold speed. The threshold speed may be, for example, between 1 km/h and 10 km/h. If the latching element is a pawl, the return spring aids disengagement of the pawl when the driving mode is to be resumed.
If the parking lock actuation mechanism comprises at least one position sensor, such as a pawl sensor, or a rotation sensor, such as a parking lock gear sensor, a motor control unit may continuously detect the present state of the parking lock. Actuation of the pawl for latching purposes can be synchronized with the rotary position of the parking lock gear.
In one embodiment of the drive, the drives provided by the drive block can also be referred to as non-branching drives.
According to a further aspect in the design and assignment of the drive combination to the respective road wheel, particularly when one of the drivable road wheels on an axle is in low-traction contact with the ground, the vehicle can be kept completely stationary by way of the other drivable road wheel on the same axle by using the separate electric motor belonging to this other road wheel and by using the associated parking lock. The stationary state of the vehicle is ensured since activation of the first parking lock of one road wheel (the one without traction) simultaneously locks the other road wheel (with traction) against rotation by activating the second parking lock of this other road wheel. By branching the flow of force from the parking lock actuator, a single parking lock actuator is able to engage two parking locks simultaneously.
From an idealized perspective, a person looking at a schematic vehicle structure who has directed their gaze to the drive block along the longitudinal vehicle direction sees a flat projection of the components of the drive block within the outline of the vehicle, wherein, due to the sequence of the components along the vehicle longitudinal direction, the components arranged closer to the viewer may at least partially overlap these other components, i.e. the components arranged further away from the viewer. The two electric machines of the drive block are arranged one after the other along the longitudinal vehicle direction so that only part of the outlines can be seen in a projection of the outlines of the electric machines because these overlap, so that the surface areas enclosed by the outlines (in said projection) are at least partially congruent with each other. If a conceptual abstract view is not just flat, but rather spatial, i.e. if the spatial dimension along the longitudinal vehicle direction is added, then it is possible to speak of a partially aligned arrangement of the electric machines along the longitudinal vehicle direction, especially in such a case. In one embodiment, the overlap constitutes at least 30%, preferably at least 50%, of the cross-sectional area of each of the two electric machines. The electric machines may be at a minimum distance from each other along the longitudinal vehicle direction. A minimum distance of e.g. two centimeters enables improved cooling of the electric machines due to all-round air circulation.
The above-described arrangement of the individual components of a drive block has numerous advantages. The more sensitive components, such as e.g. the inverters, are taken out of the greatest danger zone. Stone chips and other mechanical impulses can cause significantly less damage to the housings of the electric machines than to the housings of the inverters, which due to the higher position chosen can be of more delicate design.
One very particular advantage results from the fact that laboriously developed motor vehicles with their long development times for bodies can continue to be used. Such motor vehicles can optionally be equipped with an internal combustion engine or with one of the drive blocks outlined above.
The present invention can be better understood by referencing the accompanying figures, which show examples of particularly advantageous embodiments without limiting the present invention thereto.
The drive block 1 is a single-wheel drive 205, 207 which can drive two single (road) wheels via its two independently operating single-wheel drives 205, 207. The two single-wheel drives 205, 207 are located on the same axle 209, which in the exemplary embodiment shown in
In another embodiment, which is not shown in the drawings, the single-wheel drives can be located on the front axle, see for example the axle 209I in
Based on the passenger compartment 223 and the arrangement of the steering wheel 221 on the steering linkage 225, it is clear in
The axles 209, 209I are indicated by dotted lines in
In the design example shown in
In
The first electric machine 3 has a width 45, which in part extends behind the transmission housing 27.
The inverter 11 (together with the inverter 13—see
The second electric machine 5 has a (second) width 47, which (substantially) corresponds to the diameter of the cylindrical electric machine. The (second) width 47 is approximately half the width (or depth or length) of the (second) inverter 13 mounted above the electric machine 5.
The first inverter 11 is supported by the first support plate 19. The second inverter 13 is supported by the second support plate 21.
It is particularly advantageous if the (fifth) attachment point 103 between the upper part of the housing of the inverter 13 and the support plate 21 is a damped attachment point 103, e.g. by means of a foam rubber mat.
The various supply cables 39, 39I, 41, 41I are of different length. Due to the design of the cable connection adapters 23, 25, length equalization can be accomplished in the region of or by means of the connector positionings 49, 51.
The width 47 of the second electric machine 5 corresponds to the width 45 of the first electric machine 3.
The cooling fins 61, 63, 65, 67 on the box-like housings 15, 17 of the inverters 11, 13 (cf.
It can also be seen clearly in
The (second) current path length 55 of the (second) cable routing 59 is defined by the distance between the electrical energy store 43 and the drive block 1.
The two box-like housings 15, 17 of the inverters 11, 13 are at a slight distance from each other, so that a separation gap 81 is formed between the two.
The inverters 11, 13 may be structurally identical. Simply by rotating about the vertical axis 79 of the housing, it is possible to use two inverters 11, 13 which are identical to each other and which both form part of the upper side 77 of the drive block 1 (cf.
The possible embodiments shown in the individual figures can also be combined with each other in any form.
The centrally arranged battery, such as the electrical energy store 43, may also be placed in the vehicle in a manner distributed across multiple locations. This results in even greater differences in the cable lengths of the power supply cables 39, 39I, 41, 41I.
As can be seen from
Instead of the two electric machines 3, 5 being arranged, as shown, in a manner slightly offset from each other with regard to the lowest point 75, the electric machines 3, 5 can also be arranged on the same plane with regard to the inverters 11, 13 and below the latter, if more space is available in the axial direction.
The inverters 11, 13 are placed in the area 327 remote from the ground.
As can be seen more clearly in
In order to move a vehicle, the electric machine 5, for example, transmits a torque via an input shaft 359 to a pinion 331 and onward via a geared transmission stage 351 to a road wheel on an axle (cf. axle 209 in
The two parking lock actuators 321, 323 are part of a parking lock actuation mechanism 324, which is classed as the first type. The first type of parking lock actuation mechanism 324 enables individual actuation of a respective parking lock assigned to the parking lock actuator 321, 323, such as the parking lock 319 and the parking lock 317 (see also
For the output, there is a larger pinion 333, 333I which, as can be seen with reference to the pinion 331, is driven by a smaller pinion, the pinion 331. The two pinions 331, 333I form the transfer stage 345. The small pinion 331 and the large pinion 333I are brought together to form a geared transmission stage 351 (shown in simplified form, i.e. without teeth). A further transfer stage is formed by a planetary transmission stage 349, of which it is possible to see an external toothing of a ring gear for immobilization in the transmission housing 29 (see
As can also be clearly seen from
In one embodiment variant, the locked state of the parking lock can be achieved by means of a pulling motion.
The vehicle 201 shown (schematically) in
The following is a list of reference numbers used in the drawings and this description.
1, 1I drive block
3, 3I first electric machine
5, 5I second electric machine
7 first transmission
9 second transmission
11 first inverter
13 second inverter
15 first box-like housing, in particular of the first inverter
17 second box-like housing, in particular of the second inverter
19 first support plate
21 second support plate
23 first cable connection adapter
25 second cable connection adapter
27 first transmission housing
29 second transmission housing
31 first output shaft
33 second output shaft
39, 39I first power supply cable
41, 41I second power supply cable
43 electrical energy store
45 first width of the first electric machine
47 second width of the second electric machine
49 first connector positioning
51 second connector positioning
53 first current path length
55 second current path length
57 first cable routing
59 second cable routing
61 first cooling fin
63 second cooling fin
65 third cooling fin
67 fourth cooling fin
71 installation position
73 highest point
75 lowest point
77 upper side of the drive block
79 vertical axis of housing
81 separation gap
83 first electrical connection
85 second electrical connection
87 first cooling circuit inlet
89 second cooling circuit inlet
91 first cooling circuit outlet
93 second cooling circuit outlet
95 first attachment point
97 second attachment point
99 third attachment point
101 fourth attachment point
103 fifth attachment point
201 motor vehicle
203 motor vehicle drive
205 first single-wheel drive
207 second single-wheel drive
209 axle, in particular motor vehicle axle, implemented with two single-wheel drives
209I axle, in particular motor vehicle axle, on which a steering linkage can be found
211 longitudinal vehicle direction
213 motor vehicle transverse direction
221 steering wheel
223 passenger compartment
225 steering linkage
317 first parking lock
319 second parking lock
321 first parking lock actuator, in particular of a first type of parking lock actuation mechanism
323 second parking lock actuator, in particular of a first type of parking lock actuation mechanism
324 first type of parking lock actuation mechanism
325 area close to the ground
327 area remote from the ground
331 smaller pinion
333, 333I larger pinion
335 pawl-type lock
337 pawl
339 spring energy store
341, 341I ring gear, in particular parking lock ring gear
343 toothed outer rim, in particular of the ring gear
345 transfer stage
347 parking lock actuator of a second type of parking lock actuation mechanism
348 second type of parking lock actuation mechanism
349 planetary transmission stage
351 geared transmission stage
353, 353I actuating linkage
355 dowel pin
357, 357I output gear, in particular of a spur gear stage
359 input shaft
Claims
1-15. (canceled)
16. A drive block of an electric motor-driven motor vehicle drive for two single-wheel drives on one common axle,
- comprising a first electric machine, which has a first rotor axis, and
- comprising a first transmission arranged on an end face of the first electric machine, and
- comprising a second electric machine, which has a second rotor axis, and
- comprising a second transmission arranged on an end face of the second electric machine,
- which are arranged at least partially congruent with each other in a longitudinal vehicle direction for installation, and
- which are configured for transverse installation in a motor vehicle,
- wherein the drive block has two inverters, each respective inverter prepared for actuating one of the two electric machines,
- wherein the two inverters are arranged at a highest point of the drive block while being in an installation orientation and at least one of the inverters, which is arranged next to the other inverter, is designed as a shallow, almost square box and with its box shape forms approximately one half of an upper side of the drive block, and
- wherein the two electric machines are arranged in parallel with regard to their rotor axes and one behind the other with regard to their housings, as a result of which the drive block is composed of two L-shaped motor/transmission units having separate transmission housings.
17. The drive block according to claim 16, wherein the two inverters together form the upper side of the drive block, one of the inverters covers a right-hand side of the electric machines arranged one behind the other, as a shallow unit spanning the latter.
18. The drive block according to claim 16, wherein one inverter rests on a support plate, which is configured as a flat cover plate across both electric machines.
19. The drive block according to claim 16, wherein one of the inverters has a cable connection adapter by which a connector positioning is predefined at a point on a longitudinal extent or a point on a width of one of the electric machines.
20. The drive block according to claim 19, wherein each of the inverters has its own cable connection adapter as an electrical transmission means placed on a side, the connector positioning of which is placed in each case at a point on the longitudinal extent of the cable connection adapter such that an equal distance is obtained between each connector positioning and an energy source.
21. The drive block according to claim 19, wherein a first current path length, which is provided for a length of a first connection cable and a cable routing in a first cable connection adapter, and a second current path length, which is provided for a length of a second connection cable and a cable routing in a second cable connection adapter, match each other as a result of cable routings providing a compensation between different lengths for the first and second connection cables.
22. The drive block according to claim 19, wherein a cable connection adapter has multiple connectors or connector positions, to which a connection cable can be connected.
23. The drive block according to claim 16, wherein one of the transmission housings is attached to an edge side of the drive block and has an elliptical, sloping, groundwardly directed profile with two foci, one of said foci being used for a wheel output shaft.
24. The drive block according to claim 16, wherein the transmission housings, in the region of a lowest point of the drive block, extend further into an area close to the ground than a lowest point of the electric machines.
25. The drive block according to claim 16, wherein at least one of the inverters is equipped with a plurality of upwardly projecting cooling fins.
26. The drive block according to claim 16, wherein the two inverters are adjacently arranged on an upper side of the drive block and are placed in a manner rotated relative to each other about their housing vertical axes.
27. The drive block according to claim 16, wherein each of the inverters is connected via at least one of:
- its own electrical connection,
- its own cooling circuit inlet,
- its own cooling circuit outlet,
- a plurality of its attachment points
- to at least one other component of the drive block.
28. A drive block of an electric motor-driven motor vehicle drive for two single-wheel drives on one common axle,
- comprising a first electric machine and a first transmission arranged on an end face of the first electric machine, and
- a second electric machine and a second transmission arranged on an end face of the second electric machine,
- and comprising two parking locks and a parking lock actuation mechanism,
- wherein in each case one inverter, one electric machine and one form a drive combination, which constitutes a separate drive,
- each separate drive being equipped with one of the two parking locks for blocking an output shaft that leads out of the drive to a wheel drive,
- and in that the electric machines are arranged at least partially congruent with each other in a longitudinal vehicle direction and
- are designed for installation in a motor vehicle transverse direction,
- and in that the parking lock actuation mechanism, which comprises
- either a single parking lock actuator for synchronously actuating the two parking locks to create a locked state, or
- two parking lock actuators for creating a locked state in each drive combination,
- is situated between the transmissions in an area close to the ground when the drive block is in an installation position.
29. The drive block according to claim 28, wherein each parking lock in the locked state causes inhibition of rotation by means of the associated transmission.
30. The drive block according to claim 28, wherein at least one of the parking locks is designed comprising at least one of the following configurations:
- the at least one parking lock in the locked state rotationally immobilizes a planetary transmission stage of the transmission by engaging in a planet carrier,
- the at least one parking lock in the locked state rotationally immobilizes an output gear,
- the at least one parking lock rotationally immobilizes an input shaft of the transmission,
- a smaller pinion of two pinions that form a transfer stage is blocked when the parking lock is in an engaged state.
31. The drive block according to claim 16, wherein the drive block comprises one parking lock or two parking locks, which are designed to be actuated by either one actuation mechanism or by two actuation mechanisms.
32. The drive block according to claim 16, wherein the inverters are placed as inverters arranged as a point-symmetrical mirror image of each other relative to a separation gap therebetween.
33. The drive block according to claim 19, wherein a power supply cable from an electrical energy store can be connected to the cable connection adapter.
34. The drive block according to claim 19, wherein the cable connection adapter is oriented sideways and configured for being connected to a central energy source in an exchangeable manner.
35. The drive block according to claim 28, wherein the parking lock is a pawl-type lock which is configured to be actuated hydraulically or by an electric motor or by comprising a spring energy store.
Type: Application
Filed: Aug 31, 2021
Publication Date: Aug 17, 2023
Inventors: Severin Schneider (Tennenbronn), Dennis Dorner (Stuttgart), Pascal Walter (Korb)
Application Number: 18/024,755