Patent Description:
Furthermore, the present invention relates to a vehicle, in particular a vehicle without its own drive.

Vehicles without their own drive may, for example, be trailers such as caravans, boat trailers, horse trailers or the like. In the case of such vehicles, it is considered problematic that they can only be moved with difficulty by hand when they are not connected to the towing vehicle, for example a passenger car. In the case of a caravan trailer, for example, which has been disconnected from the car by which it was transported at a suitable point on a camp site, maneuvering by hand to the final parking position is very difficult.

In order to facilitate maneuvering in the disconnected state, maneuvering drive systems have been developed which can be mounted on a vehicle without its own drive. Such a maneuvering drive system usually comprises at least two drive units by means of which the wheels of the vehicle to be moved can be set in rotation. The drive units are mounted on the outside of a vehicle, usually in an area immediately in front of or behind the wheels which are to be driven by the drive units. The drive units each comprise on their front side a rotatable drive element, for example a friction wheel, which is brought into frictional contact with a wheel of the vehicle, so that rotation of the drive element causes rotation of the wheel of the vehicle. Each drive element is assigned an electrical drive motor, which is coupled to the drive element and is able to set the drive element into rotation.

If, in the case of a single-axle vehicle, such a drive unit is mounted in the area of each of the two wheels or, in the case of a two-axle or multi-axle vehicle, such a drive unit is mounted in the area of each wheel of at least one of the axles, the vehicle can be comfortable moved by a user using the drive units. Such maneuvering drive systems, in particular the drive units, normally are operated with a power supply at an electrical voltage of <NUM> V. Such an electrical voltage can be supplied by standard batteries. However, it is sometimes considered as disadvantageous that such a voltage requires a high electrical current which may lead to power losses in particular in the cables between the battery and the drive motor as the power loss is directly dependent from the electrical current.

<CIT> discloses a maneuvering drive system comprising two drive units, which are designed to be attached to a vehicle in order to drive a wheel of the vehicle. Further maneuvering drive systems are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

Based on this prior art, it is an object of the present invention to provide an alternative maneuvering drive system, which in particular avoids the above-mentioned disadvantages.

This object is solved in a maneuvering drive system mentioned at the beginning in that the battery is designed to supply an electrical voltage for operation of the drive motor of <NUM> V.

Correspondingly, the object is also solved by a vehicle, in particular a vehicle without its own drive, comprising such a maneuvering drive system. The vehicle can be in particular a trailer, preferably a caravan, boat or horse trailer.

The idea is based on the consideration to provide a battery that delivers a voltage of <NUM> V and, correspondingly, to provide drive motors that can be operated at such an electrical voltage. In this way, it is possible to increase the output power of the motor and/or to design the drive units in a very space-saving way.

In concrete terms, the power loss in cables is dependent from the electrical current, the length of the cables and the specific resistance determined by the material of the cable. The power losses appear in all cables between the battery, a possible control device and the motor itself. As a higher electrical voltage leads to a reduced electrical current, the power losses are significantly reduced so that, at the same input power, the output power of the drive motor is significantly increased.

It has been proven in particular advantageous if the electrical voltage supplied by the battery and used for operation of the drive motor is <NUM> V. On one hand, such a voltage is not dangerous for the human body when a person comes accidentally into contact with a non-isolated component. On the other hand, such a voltage, which is three times the voltage at which common drive units operate, leads to a significant reduction of power losses. In addition, electronic parts such as cable, switches, connectors etc. can be adapted to a lower current specification, which is also an economic advantage. Also, a voltage of <NUM> V is easy to achieve by combining standard DC-batteries supplying a voltage of <NUM> V. Accordingly, it has been proven that a voltage of <NUM> V is optimized in particular in respect to safety, economic and efficiency issues.

Preferably, the drive motors are brushless motors. Brushless motors are characterized by a high power-to-weight ratio and low maintenance efforts. Normally, motors equipped with brushes have the tendency to break as the brushes are subjected to wearing. Furthermore, a brushless motor does not need a tolerance gap between the power brush, so it has per se a higher power efficiency. Due to the fact that no slipperings or commutators and no brushes are necessary, a brushless motor has less friction. Furthermore, at brushless motors, it is easier to monitor and control the rotation speed, which makes it easier to move a vehicle without its own drive in a straight line. The size and weight of a brushless motor is also smaller compared to a motor equipped with brushes having the same power. In particular, the combination of a brushless motor with a higher voltage of more than <NUM> V is advantageous, as the electrical current is reduced. Generally, high electrical currents often cannot be tolerated by a brushless motor due to demagnetization effects. Accordingly, the combination of providing a brushless motor at an increased voltage leads to a very space-saving, highly efficient and long service life functioning.

The electrical drive motors may have an internal rotor. Accordingly, the motors may be formed such that the stationary part (stator) of the motor encloses the moving part (rotor).

According to a further elaboration of the invention, the drive motors may comprise a rotor information detection device, in particular hall-sensors, in order to gain information about the position and/or the movement of the rotor. By means of such a rotor information detection device, it is possible to use information about the position and the movement of the rotor in order to make adaptions in the control of the motor. In particular, the rotating field of the motor can be adjusted dependent from the information gained by a rotor information detection device. Preferably, the rotor information detection device can be formed as or comprise at least one, in particular a plurality of hall-sensors, by means of which the position of the rotor can be determined exactly. The hall sensors may be distributed over the circumference, in particular equally distributed. Based on the information provided by the rotor information detection device, conclusions can be made on the rotational speed and the direction of rotation.

According to a preferred embodiment, each drive motor may define a motor axis, which extends transversally, in particular perpendicularly to the rotation axis of the drive element. Accordingly, the drive motor may be arranged such that its motor axis extends transversally, in particular perpendicularly with regard to the rotation axis of the drive element. When mounted to a vehicle, the rotation axis of the drive element extends normally parallel to the rotation axis of the wheel to be driven by the drive element. This means, that the motor axis may extend in the longitudinal direction of the vehicle to be driven. In this way, a very simple design of the drive unit is possible.

In concrete terms, the drive unit may comprise a central support element on which the drive element is mounted rotatably. This central support element may have a C- or E-shape, wherein the drive element is mounted between two legs of the C- or E-shaped central support element. Accordingly, the drive motor may be connected to a central base section of the central support element, in particular may be flanged thereto. Such a central support element allows a space-saving design and a fast assembly of the drive unit.

According to a preferred elaboration of the invention, the motor may comprise a motor shaft, which is coupled to the drive element by means of a gear device. Such a gear device allows a suitable transmission ratio between the speed of rotation of the motor shaft and the desired speed of rotation of the drive element.

Preferably, the gear device comprises a worm gear pair. By means of a such a worm gear pair, high transmission ratios can be achieved. In particular, it is possible that the motor rotates at a high speed delivering only a low momentum, which is converted into a low speed and a high momentum of the driving element, that is used to drive the wheel of a vehicle. A worm gear pair is characterized in that it comprises a worm, which is in the form of a screw, and a worm wheel, which is in engagement with the worm screw. An important advantage of a worm gear pair is that it has a self-locking effect. Accordingly, it is possible that the worm screw drives the worm wheel, but it is excluded, that the worm wheel can drive the worm screw. Contrary to classical spur gears, an electronic magnetic break need not be provided in a worm gear pair. Furthermore, the noise level is reduced.

In concrete terms, a worm screw of the worm gear pair may be connected to the motor shaft in a rotationally fixed manner or formed in a single piece design with the motor shaft. Accordingly, a high rotation speed of the motor is converted in a low speed of the worm wheel, wherein the motor can be designed such that it delivers only a low momentum which is converted into a high momentum of the worm wheel.

In a further elaboration of this embodiment, the gear device may comprise an intermediate shaft, which is mounted rotatably and which carries a worm wheel being in engagement with the worm shaft and a gear wheel in a rotationally fixed manner. Accordingly, it is provided that the worm wheel being in engagement with the worm shaft is not directly connected to the drive element in a rotationally fixed manner. Moreover, it may be provided that an intermediate shaft is held rotatably, in particular on a central support element, which intermediate shaft carries the worm wheel and a further gear wheel in a rotationally fixed manner to each other. Accordingly, a further gear stage may be provided.

In concrete terms, the gear device may comprise a spur gear stage. Such a further spur gear stage in addition to a worm gear pair may increase the transmission ratio of the gear device in total. Preferably, the spur gear stage as well as the worm gear pair may be arranged between two legs of the central support element. In particular, the gear device may be surrounded completely by the central support element and further cover elements in order to protect the gear device against external influences and to bring the different wheels of the gear device into contact with lubricant.

The spur gear stage may be formed such that the gear wheel of the intermediate shaft is in direct or indirect engagement with an output side gear wheel, which is fixed in a rotationally fixed manner to the drive element. In other words, the gear wheel of the intermediate shaft may be coupled to the drive element directly or indirectly. Preferably, the spur gear stage comprises an intermediate gear wheel held rotatably and arranged between the gear wheel on the intermediate shaft and the output side gear wheel. This embodiment is based on the consideration to realize an indirect coupling between the intermediate shaft and the drive element. In order to increase the transmission ratio, the number of teeth of the output side gear wheel can be higher than the number of teeth of the gear wheel of the intermediate shaft. In particular, the number of teeth of the output side gear wheel can be at least <NUM> times, in particular at least <NUM> times, preferably at least <NUM> times the number of teeth of the gear wheel of the intermediate shaft. In this way, the momentum which can be applied to the wheel, is increased, whereas the rotation speed of the drive element is reduced compared to the intermediate shaft.

Each drive unit may comprise a housing, which is in particular weather-resistant and/or watertight, wherein said housing surrounds at least the drive motor and accommodates the battery.

Each drive unit may comprise a control device in particular having a communication module, which control device is fixed to or integrated into the drive unit. A control device is used to regulate the rotation of the drive motor. A communication module can be arranged such that it is able to communicate with a remote control unit connected by cable or by wireless connection. The control device may be arranged directly adjacent to the battery so that the cables between the battery and the control device are short, which keeps the power losses in these cables low. The rotor information detection device may be connected to the control device.

According to a preferred embodiment, a polarity control unit may be integrated into the control device, wherein the polarity control unit is designed to regulate the direction and speed of rotation of the drive motor by changing the polarity. Preferably, the control device and the battery are integrated in one common housing. Consequently, the control device in particular comprising a polarity control unit and the battery can form an integrated unit in the drive unit, wherein they may be arranged in one common housing.

The maneuvering drive system may be arranged such that one remote control unit is able to communicate with a plurality of drive units at the same time. Accordingly, a direct communication path can be established between one remote control unit and the control devices of all, in particular both drive units. Such an arrangement leads to only a low delay during communication. However, such an arrangement is more complex for maintenance and problem tracking as the control devices of both drive units have their own receiving and controlling parts.

Alternatively, the control device of one drive unit may be formed as a master control device, which is able to communicate with a remote control unit, and the control device(s) of the other drive units is/are formed as slave control device(s) so that it is/they are able to communicate with the master control device in order to get instructions from the latter. In other words, the control device of one drive unit serves as a master control device and the control device of the other drive unit serves as a slave device. Accordingly, a communication signal from a remote control unit is at first transmitted to the master control device and from the master control device to the slave device/ devices. This design allows to use a Bluetooth connection between the remote control unit and the master control device. The maneuvering drive system may comprise a remote control unit which is able to communicate with one or a plurality of control devices of drive units.

In addition, an infeed device may be assigned to each drive unit, wherein the infeed device can bring the drive unit into a frictional and driving contact between its drive element and the wheel of the vehicle to be driven, in particular by a guided linear or pivoting movement. By means of such an infeed device, it is possible that the maneuvering drive system remains permanently at the vehicle to be driven. Accordingly, the drive elements are only brought in contact with the corresponding wheel of the vehicle to be driven, when the vehicle should be moved. If the vehicle to be driven, for example a trailer, is connected to a passenger car and moved, the drive elements can be brought out of engagement from the wheel of the vehicle.

Preferably, the infeed device comprises an infeed motor by means of which the infeed movement can be carried out in a motorized manner. In order to control the infeed device, the infeed motor can be connected to the control device associated with the respective drive unit. The infeed motor may be supplied by the battery. Accordingly, the infeed motor may be able to be operated at an electrical voltage of more than <NUM> V, in particular at an electrical voltage of <NUM>, <NUM> or <NUM> V.

In order to protect the infeed motor against external influences, in particular against dirt and dust, the infeed device may comprise a weather-resistant and/or watertight infeed housing, which surrounds at least the infeed motor.

Further features and advantages of the present invention will become clear by the following description of an embodiment of a maneuvering drive system according to the invention with reference to the enclosed drawing. In the drawing shows:.

<FIG> shows a part of a single-axle caravan trailer <NUM> having two wheels <NUM> on opposite lateral sides. At its front end, the caravan trailer <NUM> comprises a coupling device (not visible) in order to attach the trailer <NUM> to the trailer hitch of a vehicle. The caravan trailer <NUM> does not have its own drive and, when it is not connected to a passenger car serving as a towing vehicle, can hardly be moved by hand, in particular can hardly be maneuvered. Therefore, the caravan trailer <NUM> is equipped with an maneuvering drive system <NUM> according to the invention.

The maneuvering drive system <NUM> comprises exactly two drive units <NUM>, which are shown more in detail in <FIG>. The drive units <NUM> are attached to a square tube <NUM>, which connects the two drive units <NUM> and which is attached to the caravan trailer <NUM> by means of suitable clamping elements (not visible). The length of the square tube <NUM> is chosen such that each drive unit <NUM> is arranged directly behind a wheel <NUM> of the caravan trailer <NUM>.

By means of the two drive units <NUM>, the wheels <NUM> of the caravan trailer <NUM> can be driven and, consequently, the caravan trailer <NUM> can be moved, in particular maneuvered, without a towing vehicle. For this purpose, each of the drive units <NUM> comprises a rotatably mounted drive element, specifically a friction roller <NUM>, which is designed and arranged such that it can be brought into abutment with a wheel <NUM> of the caravan trailer <NUM> in order to drive the latter. The friction roller <NUM> has a basically cylindrical shape and comprises in its outer circumference several grooves extending in the longitudinal direction of the friction roller <NUM>.

As it is in particular visible in <FIG>, each drive unit <NUM> comprises a central support element <NUM> having a base section <NUM> extending parallel to the rotation axis of the friction roller <NUM> and two legs <NUM> projecting frontwards from the base section <NUM>. The friction roller <NUM> is mounted rotatably between the two legs <NUM>.

Furthermore, each drive unit <NUM> comprises an electrical brushless drive motor <NUM>, which is flanged to the base section <NUM>. Each electrical drive motor <NUM> comprises a motor shaft <NUM>, which is coupled to the friction roller <NUM> by means of a gear device. This gear device <NUM> is arranged inside a corresponding gear housing <NUM> and located next to the friction roller <NUM> on the opposite side of the leg <NUM> shown on the left side in <FIG>. In concrete terms, the gear device <NUM> comprises a worm gear pair <NUM>. In this way, a high transmission ratio can be achieved. A worm screw <NUM> of the worm gear pair <NUM> is connected to the motor shaft <NUM> in a rotationally fixed manner.

The gear device <NUM> further comprises an intermediate shaft <NUM>, which is mounted rotatably with respect to the gear housing <NUM> and which carries a worm wheel <NUM> being in engagement with the worm screw <NUM>. The intermediate shaft <NUM> also carries a gear wheel <NUM>, wherein the gear wheel <NUM> and the worm wheel <NUM> are mounted together via the intermediate shaft <NUM> in a rotationally fixed manner.

In order to further increase the transmission ratio, the gear device <NUM> also has a spur gear stage <NUM>. The spur gear stage <NUM> is formed such that the gear wheel <NUM> of the intermediate shaft <NUM> is in indirect engagement with an output side gear wheel <NUM>, which is fixed in a rotationally fixed manner to the friction roller <NUM>. In concrete terms, the spur gear stage comprises an intermediate gear wheel <NUM> held rotatably on the left side of the gear housing <NUM> (in <FIG>) and arranged between the gear wheel <NUM> on the intermediate shaft <NUM> and the output side gear wheel <NUM>. As it is visible in <FIG> and <FIG>, due to the configuration of the gear device <NUM>, the motor axis X defined by the motor shaft <NUM> extends perpendicularly to the rotation axis of the friction roller <NUM>.

Each drive unit further comprises a battery <NUM>, which is designed to be rechargeable, for supplying the drive unit <NUM> with electrical energy. The battery <NUM> is designed to supply an electrical voltage for operation of the drive motor <NUM> of <NUM> V. Accordingly, the drive motor <NUM> is designed to be operated at such a voltage. As it is visible in <FIG>, the battery <NUM> is mounted to the central support element <NUM> from a rear side.

On the top of the battery <NUM>, a control device <NUM> is arranged. This control device is also fixed to the central support element <NUM> and is used to regulate the rotation of the drive motor <NUM>. Furthermore, a communication module is provided which is able to communicate with a remote control unit connected by wireless connection. Furthermore, the communication module is designed such that the control devices <NUM> of both drive units <NUM> can communicate to each other in order to ensure a synchronous rotation of the drive motors <NUM> of both drive units <NUM>.

In addition, an infeed device <NUM> is assigned to each drive unit <NUM>. The infeed device <NUM> is designed such that it can bring the drive unit <NUM> into a frictional and driving contact between its friction roller and the wheel <NUM> of the caravan trailer <NUM>. In concrete terms, the infeed device <NUM> comprises an infeed motor <NUM>, by means of which the infeed movement can be carried out in a motorized manner. The infeed motor <NUM>, which is also designed to be operated at a voltage of <NUM> V and supplied by the battery <NUM>, is attached to a base plate <NUM>, which is fixed, in particular welded to the square tube <NUM> and extends perpendicularly to the longitudinal direction of the square tube <NUM>. The drive unit <NUM> can be moved relative to the base plate <NUM> and is guided by means of oblong holes <NUM> formed in the base plate <NUM>. Corresponding guiding bolts <NUM> extend through these oblong holes <NUM>. In this way, the infeed movement of the drive unit <NUM> is guided with respect to the square tube <NUM>, which itself is fixed to the caravan trailer <NUM>.

As it is visible on <FIG>, each drive unit <NUM> also comprises a housing <NUM>, which is weather-resistant and watertight. The housing <NUM> is attached to the central support element <NUM> and surrounds the drive motor <NUM>, the battery <NUM>, the control device <NUM> and the infeed motor <NUM>. In this way, these elements are protected against water and dirt. The batteries <NUM> can be arranged inside the housing such that they are exchangeable. In other words, a mechanism can be provided which allows to replace the battery <NUM>. Furthermore, a charging connection can be provided on the housing <NUM> in order to charge the battery <NUM> from outside. Such a charging connection may comprise two charging poles.

Because the drive motor <NUM> is brushlessand the momentum is transmitted at a high transmission ratio due to the worm gear pair, the design is very space-saving, so that high momentums can be transferred from the friction roller <NUM> to the wheel <NUM> of the caravan trailer <NUM>. Due to the worm gear pair, an additional break in the motor <NUM> is not necessary. In addition, due to the high voltage, the current is reduced so that power losses in the cables between the battery and the motors are reduced as well, which increases the efficiency of the maneuvering drive system <NUM> and avoids demagnetization effects in the brushless drive motor <NUM>.

Claim 1:
Maneuvering drive system (<NUM>) for a vehicle, in particular for a vehicle without its own drive, preferably for a trailer, comprising at least two, in particular exactly two drive units (<NUM>), which are designed to be attached to a vehicle in order to drive a wheel (<NUM>) of the vehicle, each drive unit (<NUM>) comprising
a rotatably mounted drive element which is designed and arranged such that it can be brought into abutment with a wheel (<NUM>) of the vehicle to drive the vehicle,
an electrical drive motor (<NUM>), which is designed to set the drive element in rotation,
a battery (<NUM>), which is in particular designed to be rechargeable, for supplying the drive unit (<NUM>) with electrical energy,
characterised in that
the battery (<NUM>) is designed to supply an electrical voltage for operation of the drive motor (<NUM>) of <NUM> V.