Patent Description:
In known parking lock arrangements, it is generally the case that the drive train is locked via a parking lock wheel which is arranged rotationally conjointly on a shaft of the drive train and which has a toothing and which, by means of a parking lock pawl mounted pivotably on a parallel axle and having a lock element in the form of a locking tooth, can be locked in a form-fitting manner at the toothing. Here, the parking lock pawl is preloaded by the force of a restoring spring either away from the parking lock wheel into an unlocked position or towards the parking lock wheel into the locking position. For the purpose of pivoting the parking lock pawl counter to the force of the restoring spring, besides hydraulic parking lock actuators, use may also be made of electrical or electromechanical parking lock actuators which serve for generating a linear movement, or an at least substantially linear movement, via which an actuation element is movable towards the parking lock pawl in order to pivot the latter.

Such parking lock arrangements are known from the prior art. In this regard, <CIT> discloses a parking lock arrangement having a lock element which is formed by a locking tooth of a rotatably mounted pawl which, by means of a control element which is movable back and forth in a substantially linear manner, is adjustable between a release position and a locking position which arrests a gearing. Here, the control element is actuated by an actuator which comprises two redundant electromagnets.

Document <CIT> discloses a parking lock arrangement of the type mentioned in the introduction for a motor vehicle with electric drive. Said parking lock arrangement comprises a sliding element which is movable in a translational manner by an actuator and which, via a conical pressure surface, interacts with a pivotably mounted pawl. The pawl has on the inside a locking tooth which can, as a lock element, be adjusted between a locking position and an unlocking position during a pivoting movement of the pawl along a circular movement path. In the locking position, the locking tooth engages in a form-fitting manner into one of multiple latching cutouts which are distributed over the circumference of a parking lock wheel. The parking lock wheel is connected rotationally conjointly to a shaft of the drive train of the motor vehicle, with the result, in the locking position of the pawl or in the locking position of the lock element, that the drive train is prevented from performing a rotational movement and thus the motor vehicle is prevented from rolling away. By contrast, in the unlocking position, selectively actuable via the actuator, of the pawl or in the associated release position of the lock element, this form-fitting engagement is eliminated, with the result that the components of the drive train can rotate freely.

Document <CIT> discloses a parking lock arrangement falling within the wording of the pre-characterizing portion of claim <NUM>.

The present invention is based on the object of proposing a parking lock arrangement for an electromotively driven motor vehicle (also called electric vehicle) which is of the simplest possible design.

Said object is achieved according to the invention by a parking lock arrangement according to Claim <NUM>. Advantageous configurations and expedient refinements of the invention will emerge from the dependent claims, the description or the figures.

According to the invention as claimed in claim <NUM>, the lock element is moved only in a translational manner between the locking position and the release position.

A major advantage of the invention as claimed in claim <NUM> is that no parking lock pawl is required. Therefore, besides a particularly simple construction, the parking lock arrangement according to the invention is also distinguished especially by a compact design, which allows simple accommodation even with confined installation space conditions.

A further advantage is that, in this case, owing to the omission of a spring-loaded pawl, it is also possible for the parking lock actuator to be of particular simple design.

According to the invention as claimed in claim <NUM>, the lock element is a bar or pin which is mounted in a housing of the parking lock actuator and which is mounted in an axially displaceable manner.

Here, the pin or bar may be mounted directly or indirectly, in particular via a rod fastened thereto. Preferably, the pin or a rod connected to the latter is, via slide bearings, mounted in an axially displaceable manner in a housing of the parking lock actuator.

Preferably, the parking lock actuator has a housing which is in particular of multi-part design and in which the lock element is mounted in an axially displaceable manner, wherein a free end of the lock element, at least in the locking position, projects from the housing and engages into a cutout of the parking lock wheel in a form-fitting manner outside the housing.

According to a particularly preferred embodiment, it is proposed that the cutouts in the parking lock wheel are formed in an axial direction, wherein the lock element is mounted so as to be displaceable parallel to the axis of rotation of the parking lock wheel and, in the locking position, engages axially into one of the cutouts. The axial cutouts may in this case also be formed as passage bores.

According to an alternative embodiment, it is proposed that the cutouts in the parking lock wheel are formed in a radial direction, wherein the lock element is mounted so as to be displaceable perpendicular to the axis of rotation of the parking lock wheel and, in the locking position, engages radially into one of the cutouts. Here, the cutouts, as in the case of the conventional parking locks operating with a pawl, are arranged in the outer circumference of the parking lock wheel in a manner similar to a toothed gear.

According to the invention as claimed in claim <NUM>, the parking lock actuator is an electromechanical actuator.

According to a particularly preferred embodiment, it is proposed here that the parking lock actuator comprises an electromagnet in the form of a solenoid having a solenoid plunger which interacts with a coil, wherein the solenoid plunger is connected fixedly to the lock element or forms, with a sub-region thereof, the lock element. Thus, through electrical energization or absence of electrical energization of the axially fixed coil, the lock element can be adjusted between the locking position and the release position.

According to the invention as claimed in claim <NUM>, the parking lock actuator comprises two axially adjacently arranged solenoids having a reversing solenoid acting in both directions and having two axially adjacently situated coils. In such double-acting solenoids, which are known per se, both coils can be electrically energized separately from one another in order, in this way, to adjust the lock element between the locking position and the release position.

For the purpose of securing the locking position and the release position, it is particularly expedient if provision is made of locking means which act in a form-fitting and/or force-fitting manner and by way of which the lock element can, in both positions, be fixed mechanically, in particular in a latching manner, in each case. Electrical energization of the coil(s) of the solenoid is then required only briefly for an adjustment of the lock element, while the lock element is securely mechanically held in the two positions, in each case even without electrical energization of the coil(s).

A particularly simple embodiment of the locking means is achieved here in that these comprise a locking body which is loaded by a compression spring, in particular a spring-loaded ball, which locking body, in the locking position and in the release position, engages, in each case in a latching manner, into a cutout, in particular into a spherical cap-shaped or spherical dome-shaped depression, which is connected fixedly to the lock element. Here, the compression spring is matched to the solenoid such that the holding force exerted by said compression spring can be overcome with the electrical energization of a coil. Alternatively, it is also possible for the locking means to comprise an additional electric magnet by way of which, with electrical energization, a spring-loaded locking body, for releasing the lock element, can be adjusted into an unlocking position.

According to an embodiment not falling within the wording of claim <NUM>, the electromechanical parking lock actuator comprises an electric motor whose output shaft is operatively connected to the lock element via a gearing mechanism, wherein the gearing mechanism serves to convert a rotational movement of the output shaft of the motor into an axial movement of the lock element. As an alternative to this, it is also possible for use to be made of an electric motor which generates, instead of a rotating movement, directly a translational movement and thus forms a linear drive.

It is particularly advantageous if at least one sensor, formed as an angle sensor, is arranged for position detection of the parking lock wheel. In this case, prior to the engagement of the parking lock, it it is possible to detect whether one of the cutouts of the parking lock wheel is situated in front of the lock element such that the latter can be adjusted into the locking position easily, in particular without contact with the wall portions of the parking lock wheel that delimit the cutout. If the sensor detects a position of the parking lock wheel which differs from this state, the electric motor of the vehicle can firstly be activated by a control unit of the parking lock arrangement such that the parking lock wheel is rotated slightly into the desired position with a cutout oriented exactly to the lock element.

According to the invention as claimed in claim <NUM>, one or more sensors are provided in the parking lock arrangement for position detection of the lock element. By way of such displacement sensors, an indication can be made to a control unit of the parking lock arrangement as to whether the lock element is situated in the locking position or in the release position.

The present invention also relates to a motor vehicle with electric drive which comprises a parking lock arrangement of the above-described type. In this case, the motor vehicle may either be driven purely electromotively or have a hybrid drive, that is to say, in addition to an electric motor, also have an internal combustion engine.

Further advantages and features of the invention will emerge from the following description with regard to the exemplary embodiments illustrated in the drawings. In the drawings:.

<FIG> shows a parking lock arrangement <NUM> which is intended for installation in a motor vehicle driven by an electric motor. The parking lock arrangement <NUM> has, in a manner known per se, a parking lock wheel <NUM> which is arranged in a rotationally conjoint and axially fixed manner on a shaft <NUM> in the drive train of the motor vehicle. In deviation from the conventional embodiment, the parking lock wheel <NUM> has between its outer circumference <NUM> and the shaft <NUM> multiple cutouts <NUM>, which are formed here by passage bores and are distributed uniformly over the circumference of said parking lock wheel.

For form-fitting arresting of the drive train, the parking lock arrangement <NUM> comprises a lock element <NUM>, which is formed here by a pin. The lock element <NUM> is mounted in an actuator housing <NUM> (illustrated only in <FIG>), which is fixed relative to the chassis of the motor vehicle, so as to be adjustable in a translational manner between a locking position S (<FIG>, <FIG>) and a release position F (<FIG>) along a rectilinear movement path <NUM> in the direction of the longitudinal extent of said lock element. In the locking position S, the lock element <NUM> engages in a form-fitting manner into one of the cutouts <NUM> of the parking lock wheel <NUM> such that the parking lock wheel <NUM> and the shaft <NUM> in the drive train, which is connected rotationally conjointly thereto, and ultimately also the wheels of the motor vehicle, which are operatively connected rotationally conjointly thereto, are prevented from performing a rotational movement. In the release position F, the lock element <NUM> is in a state fully retracted from the cutouts <NUM> of the parking lock wheel <NUM>, with the result that said lock element is out of engagement with said cutouts, and that the parking lock wheel <NUM> and thus also the drive train and the wheels of the motor vehicle that are operatively connected thereto are freely rotatable.

For the purpose of adjusting the lock element <NUM>, provision is also made of an electromagnetic parking lock actuator <NUM>, which comprises here a reversing solenoid <NUM> having two axially adjacently arranged coils 30a and 30b and having a solenoid plunger <NUM> which is displaceably received therein. The two coils 30a and 30b are arranged parallel to (<FIG>) or coaxially with (<FIG>) the longitudinal extent of the lock element <NUM>, with the result that the solenoid plunger <NUM> can move back and forth in a rectilinear manner parallel to or coaxially with the lock element <NUM>. The solenoid plunger <NUM> is connected fixedly to the lock element <NUM>, with the result that, by selective electrical energization of one of the two coils 30a or 30b, the solenoid plunger <NUM> is drawn into the respective coil 30a or 30b and in the process the lock element <NUM> is also correspondingly adjusted along its rectilinear movement path <NUM>. The electrical energization of the coils 30a, 30b is realized via a control unit (not illustrated here) of the parking lock arrangement <NUM>.

The parking lock actuator <NUM> shown in the exemplary embodiment in <FIG> comprises an actuator housing <NUM>, which is preferably injection-moulded from a plastic and, via fastening lugs (not illustrated in more detail here), can be fastened in the motor vehicle in a manner known per se, for example by means of screws. At its front side, which is situated on the left in <FIG> and <FIG>, the actuator housing <NUM> is closed by a housing cover <NUM> which is manufactured from metal. Integrally formed on the housing cover <NUM> is a collar <NUM> having an inner duct, in which the pin <NUM> forming the lock element is received in an axially displaceable manner. For this purpose, the pin is fastened to the front end of an actuation rod <NUM> which, by means of two slide bearings <NUM>, is mounted in an axially displaceable manner in the actuator housing <NUM>.

Also in the actuator housing <NUM>, the two coils 30a and 30b of the reversing solenoid <NUM> are received in in each case one coil carrier <NUM>, which for its part is accommodated in in each case one magnet housing <NUM>, which is of multi-part design here. The solenoid plunger <NUM>, formed by an iron core, of the reversing solenoid <NUM> is fastened on the actuation rod <NUM> radially inside the two magnet housings <NUM>. The solenoid plunger <NUM> is situated axially between the two slide bearings <NUM>, which are attached to the inner side of the two magnet housings <NUM>.

By electrical energization of the rear coil 30a, which is situated on the right in <FIG> and <FIG>, the solenoid plunger <NUM> and, together therewith, the actuation rod <NUM> are drawn to the right until the solenoid plunger bears against a shoulder of the rear slide bearing <NUM>, which shoulder forms an axial stop. The pin <NUM> forming the lock element is then entirely in the duct of the collar <NUM> in the release position F (<FIG>). A scraper <NUM> is arranged at the front of the collar <NUM> and bears with its radially inwardly pointing lip on the pin <NUM>.

If, by contrast, the front coil 30b, which is situated on the left in <FIG> and <FIG>, is electrically energized, the solenoid plunger <NUM> and, together therewith, the actuation rod <NUM> are drawn to the left until the solenoid plunger bears against a shoulder of the front slide bearing <NUM>, which shoulder forms an axial stop. In this way, the pin <NUM> forming the lock element protrudes axially out of the collar <NUM> (<FIG>), with the result that said pin, in the locking position S, for blocking the drive train, can engage in a form-fitting manner into a cutout <NUM> of the parking lock wheel <NUM>.

For the purpose of securing the locking position S and the release position F in the case of the coils 30a and 30b not being electrically energized, provision is made of locking means <NUM> which act in a form-fitting and force-fitting manner on the collar <NUM>. For this purpose, a ball <NUM> loaded by a compression spring <NUM> is received in a transverse bore and, in the locking position S and the release position F, engages in a latching manner in in each case one notch <NUM> or 54F, respectively of the pin <NUM>.

Also arranged in the actuator housing <NUM> are two magnetically acting position sensors <NUM> and 56F, which respond to a position magnet <NUM> fastened on the actuation rod <NUM>. In this way, it is possible to detect whether the pin <NUM> is in the locking position S or in the release position F.

For the purpose of connecting the coils 30a and 30b of the reversing solenoid <NUM> and the two position sensors <NUM> to an external control unit, the parking lock actuator <NUM> has an common electrical interface <NUM> integrated into the actuator housing <NUM>, which interface is arranged in the rear region of the actuator housing <NUM>.

In the embodiment not according to the invention that is illustrated in <FIG>, the parking lock arrangement comprises a pivotably mounted pawl <NUM> and a parking lock wheel <NUM> which has on the outer circumferential side a toothing <NUM>. The pawl <NUM> has a locking tooth <NUM>, which forms the lock element <NUM> and, in the locking position S, in a conventional manner, engages from the outside into a cutout <NUM> of the parking lock wheel <NUM> that is formed in the toothing <NUM>. Here, the pawl <NUM> is preloaded into the locking position S by a spring <NUM>. For the purpose of adjusting the pawl <NUM> and thus also the lock element <NUM> into the release position F, a solenoid <NUM> is arranged as a parking lock actuator. Upon electrical energization of the coil <NUM> thereof, the solenoid plunger <NUM> is drawn into the coil <NUM> and in the process the pawl <NUM>, which is connected thereto, is, counter to the preload force exerted by the spring <NUM>, pivoted to such an extent that the locking tooth <NUM> is no longer in engagement with the toothing <NUM> of the parking lock wheel <NUM>.

Claim 1:
Parking lock arrangement (<NUM>) for an electromotively driven motor vehicle, comprising
- a parking lock wheel (<NUM>) which is rotationally conjoint with respect to a shaft (<NUM>) in the drive train and which has multiple cutouts (<NUM>),
- a lock element (<NUM>) which is movable between a locking position (S-Fig.<NUM>-<NUM>) and a release position (F-Fig.<NUM>-<NUM>) along a movement path (<NUM>) and which, in the locking position (S), engages in a form-fitting manner into a cutout (<NUM>) of the parking lock wheel (<NUM>) and, in the release position (F), is out of engagement with the cutouts (<NUM>) of the parking lock wheel (<NUM>),
- a parking lock actuator (<NUM>) which is operatively connected to the lock element (<NUM>) and by way of which the lock element (<NUM>) is adjustable between the locking position (S) and the release position (F) along its movement path (<NUM>), the parking lock actuator (<NUM>) is an electromechanical actuator comprising a reversing solenoid (<NUM>) acting in both directions and having a solenoid plunger (<NUM>) connected fixedly to the lock element (<NUM>),
- the lock element (<NUM>) is a pin or bar which is mounted in an axially displaceable manner in a housing (<NUM>) of the parking lock actuator (<NUM>),
- at least one sensor (<NUM>, 56F) is arranged for position detection of the lock element (<NUM>),
characterized in that
the parking lock actuator (<NUM>) has two axially adjacently situated coils (30a, 30b) which surround the solenoid plunger (<NUM>), U
and in that, for the purpose of connecting the coils (30a, 30b) and the position sensor (<NUM>, 56F) to an external control unit, the parking lock actuator (<NUM>) has a common electrical interface (<NUM>) integrated into the actuator housing (<NUM>).