Contacting unit with hydraulic lifting apparatus and method for controlling the contacting unit

Abstract

The invention proposes a contacting unit (1) for a charging station for electrically charging an electric vehicle (2), having a charging contact (4), which is adjustable at least in terms of height, for making contact with a charging connection (3) of the electric vehicle (2), having a lifting apparatus (7) which is coupled in terms of movement to the charging contact (4) and is designed to move the charging contact (4) between a charging position and a non-charging position (100, 101), wherein the lifting apparatus (7) is a hydraulic lifting apparatus (7) which is designed to generate a hydraulic actuating force (103) under the effect of a weight force (102) of the electric vehicle (2) in order to transfer the charging contact (4) from the non-charging position (101) into the charging position (100).

Description

[0001] Contacting unit with hydraulic lifting device and method for controlling the contacting unit

[0002] The invention relates to a contact unit for a charging station for electrically charging an electric vehicle. Furthermore, the invention relates to a method for controlling the contact unit.

[0003] Charging systems for electric vehicles are known in which a plug connection between the vehicle and the charging device is usually operated manually. For home charging, wall chargers known as "wall boxes" are predominantly used. These are connected to a sufficiently powerful power connection on the mains side and, based on the signals received from the vehicle, control the electrical power supplied to the vehicle for the charging process. Automated charging systems are also known, which can independently close and open a plug connection, for example, using multi-axis robots.

[0004] The document EP 3687851 A1 discloses a first component of a charging device for charging a rechargeable battery of an electric vehicle, comprising a contacting element, wherein the contacting element can be connected to a coupling element of a second component to establish an electrical connection, wherein a base and an arm arranged thereon are provided, wherein the arm is mounted on the base so as to be movable about and / or along several axes in order to guide the contacting element to the coupling element.

[0005] The object of the present invention is to propose a contacting unit that is characterized by a cost-effective design and does not require the use of additional servo motors. This object is achieved by a contacting unit having the features of claim 1 and a method having the features of claim 10. Preferred or advantageous embodiments of the invention emerge from the subclaims, the following description, and the accompanying figures.

[0006] The subject matter of the invention is a contacting unit that is designed and / or suitable for a charging station for electrically charging an electric vehicle. In particular, the charging station serves to charge an electrical energy storage device of the electric vehicle, such as a traction battery. The charging station is preferably designed as an underbody charging station, also known as an ACDU (Automatic Connecting Underbody Device). Electric vehicles can be understood to include both purely electrically powered and partially electrically powered or hybridized vehicles. An optional subject matter of the invention relates to a charging station, preferably an underbody charging station, with the contacting unit.

[0007] The contacting unit has a charging contact that is at least height-adjustable and is designed and / or suitable for contacting a charging port of the electric vehicle. In particular, “height-adjustable” means that the charging contact is movable at least vertically or in a vehicle-vertical direction relative to the charging port. In other words, the charging contact can be moved toward or away from the underbody of the electric vehicle. The charging station is particularly preferably stationary, with at least the charging contact being partially and / or at least temporarily movable beneath the electric vehicle. The charging contact is particularly preferably permanently connected to an energy source via a supply line. In the sense of the application, “contacting” is preferably understood to mean both a direct, in particular conductive, connection and an inductive connection between the charging contact and the charging port.For example, the charging contact is designed as a plug or a charging pad. Furthermore, the contacting unit has a lifting device which is motion-coupled to the charging contact and designed to move the charging contact between a charging and a non-charging position. Preferably, the lifting device is motion-coupled to the charging contact via a kinematic chain, preferably a pivoting boom. In particular, a linear movement can be translated into a pivoting and / or lifting movement of the charging contact via the kinematic chain. In particular, the charging position is understood to be a position of the charging contact in which it is electrically contacted and / or operatively connected to the charging port for transmitting electrical energy. Accordingly, the non-charging position is understood to be a position of the charging contact in which it is removed from the charging port or is not contacted and / or not operatively connected.In other words, the non-charging position is to be understood as a basic position of the charging contact.

[0008] Within the scope of the invention, it is proposed that the lifting device is a hydraulic lifting device which is designed to generate a hydraulic actuating force under the action of a weight force of the electric vehicle in order to transfer the charging contact from the non-charging position to the charging position. In particular, the lifting device is connected to the charging contact or the boom in such a way that the hydraulic actuating force results in a mechanical movement, preferably a translational movement, of the charging contact. In particular, the hydraulic lifting device is arranged and / or integrated on or in a floor surface on which the electric vehicle can be arranged in such a way that a hydraulic pressure in the lifting device is changed by the acting weight force.When the electric vehicle is parked on the ground, the hydraulic pressure is preferably increased under the influence of gravity in order to move the charging contact into the charging position. Particularly preferably, a volume change work is performed within the lifting device under the influence of gravity.

[0009] The invention is based on the consideration that electric vehicles, especially in private areas, usually have to be connected to the power grid manually. Almost all charging systems are connected to the vehicle via a cable, with the connection usually being made using an AC charging plug, e.g. a so-called wallbox. Thanks to their bidirectional charging capability, electric vehicles can be used as energy storage devices for the power grid, also known as "Vehicle to Grid (V2G)". This means that a driver who wants to make their vehicle available to the V2G system has to manually establish the electrical connection to the charging system every time they stop in their home garage or in a parking lot; otherwise the vehicle would not be available to the V2G system.Given that humans generally react rather sluggishly and unwillingly to reduced comfort and mindless, repetitive tasks, the V2G system could lose a lot of potential in the future due to convenience. This problem could be further exacerbated by autonomous electric vehicles, which require a charging system that is V2G-capable without human intervention.

[0010] The advantage of the invention is that it proposes a contacting unit that is suitable for automatically charging or connecting the electric vehicle and is therefore particularly suitable for connection to the V2G system. The hydraulic lifting device also proposes a contacting unit that can be implemented particularly cost-effectively and does not require the use of additional actuators. A further advantage is that the lifting device does not require an external power supply, in particular a power connection, and is therefore particularly easy to install.

[0011] In a specific embodiment, the lifting device is provided with at least one master cylinder that can be actuated by weight, and one slave cylinder that is motion-coupled to the loading contact, which are fluidly connected to one another via a hydraulic path. Under the influence of the weight, a fluid column is displaced from the master cylinder towards the slave cylinder in order to move the loading contact from the non-loading position to the loading position or to generate the actuating force. In particular, the slave cylinder is motion-coupled to the pivoting boom, so that the boom is pivoted under the influence of the actuating force. In other words, the actuating force is generated by the master cylinder as a function of the weight and passed on to the slave cylinder via the hydraulic path in order to move the loading contact into the loading position orto pivot the boom into the loading position. The hydraulic path can be formed by at least one hydraulic line, e.g., a hydraulic hose. Specifically, a master cylinder can be assigned to at least two vehicle wheels, preferably to each vehicle wheel. Thus, a contact unit is proposed that is characterized by a particularly simple and cost-effective design.

[0012] In a further development, the master cylinder has a piston designed as a base plate, the piston surface of which corresponds to at least one wheel contact area of ​​at least or exactly one vehicle wheel of the electric vehicle. In particular, a wheel load can be transferred to the piston via the base plate as the weight force for actuating the master cylinder. The wheel load preferably acts orthogonally or perpendicularly to the piston surface. In particular, the master cylinder has a cylinder housing in which the piston is slidably received. The cylinder housing can be at least partially or completely recessed or retractable into the base surface. In particular, the base plate is arranged flush and / or level with the base surface and / or without offset in a basic position of the piston. Under the influence of the weight force, the piston can be transferred from the basic position into an engaged actuating position.The wheel contact area is preferably understood to mean the tire contact area. The piston area is particularly preferably larger than the wheel contact area. For example, the piston area corresponds to more than twice, preferably more than three times, and especially more than four times the wheel contact area. The larger the piston area, the smaller the piston stroke required to provide the fluid volume required to actuate the slave cylinder. The master cylinder preferably has a return device designed to apply a return force to the piston in the direction of the basic position. For example, the return device can be designed as a return spring. In principle, the piston and the cylinder housing together define a pressure chamber filled with a hydraulic fluid.Alternatively, the piston and the cylinder housing together define a receiving space in which a diaphragm filled with a hydraulic fluid is housed. This proposes a master cylinder that can be easily actuated or mounted on the base surface, thus directly converting the weight force introduced via the vehicle wheel into the hydraulic actuation force.

[0013] In a further development, the lifting device is provided with a pressure accumulator which is fluidically integrated into the hydraulic path between the master cylinder and the slave cylinder in order to absorb or store all or part of the fluid quantity displaced by the master cylinder. In particular, the pressure accumulator serves to store the fluid volume displaced by the master cylinder and to make it available to the slave cylinder at a later point in time, preferably when the vehicle is in an end position. In other words, the pressure accumulator has the function of making the hydraulic actuating force generated by the master cylinder available to the slave cylinder as needed and / or with a time delay in order to transfer the charging contact into the charging position. For this purpose, the hydraulic path between the pressure accumulator and the slave cylinder can be temporarily and / or at least partially shut off.Preferably, the pressure accumulator is designed as a spring-loaded accumulator. Thus, a lifting device is proposed that allows the charging contact to be transferred from the non-charging position to the charging position, regardless of the vehicle's position. This ensures that the connection between the charging contact and the vehicle-side charging port is established at all times.

[0014] In a further specific embodiment, the lifting device comprises an expansion tank which is fluidically integrated into the hydraulic path between the master cylinder and the slave cylinder, preferably between the master cylinder and the pressure accumulator, in order to completely or partially absorb or store the amount of fluid absorbed by the slave cylinder. In particular, the expansion tank serves to store the fluid volume displaced by the slave cylinder and to make it available to the master cylinder at a later time, preferably when the vehicle has been removed. In other words, the expansion tank has the function of temporarily storing the fluid volume displaced by the piston of the slave cylinder under the influence of the weight force in order to transfer the charging contact to the non-charging position. For this purpose, the hydraulic path in the direction of the expansion tank can be temporarily and / or at least partially opened.In particular, after the electric vehicle is removed, the piston of the master cylinder is moved to its home position, preferably by the reset device, while simultaneously drawing fluid from the expansion tank to fill the pressure chamber or diaphragm. Thus, a lifting device is proposed that allows the charging contact to be moved from the charging position to the non-charging position, regardless of the vehicle's position. This ensures that the connection between the charging contact and the vehicle-side charging port is disconnected at all times.

[0015] In a further embodiment, the contacting unit comprises a control device that is signal-connected to the lifting device and is designed to control the lifting device depending on a vehicle position and / or a vehicle state. In particular, the contacting unit comprises a detection device configured to detect the vehicle position. For example, the detection device can be a camera, a light barrier, or the like. Alternatively, the vehicle position and / or the vehicle state can also be transmitted directly from the vehicle to the control device, e.g., via a data network.The control device is preferably designed to control and / or influence, preferably to open and close, a flow path of the hydraulic system, preferably between the pressure accumulator and the slave cylinder and / or between the expansion tank and the master cylinder. For example, the control device opens the flow path toward the slave cylinder when the electric vehicle is arranged in the end position in order to transfer the charging contact into the charging position. Optionally, the control device closes the flow path toward the slave cylinder when the charging contact is arranged in the charging position and / or in the non-charging position in order to fix the charging contact in the respective position.For example, the control device releases the flow path toward the expansion tank when the electric vehicle is positioned in the end position and / or a charging process is aborted and / or the electric vehicle is started in order to transfer the charging contact to the non-charging position. Optionally, the control device blocks the flow path toward the expansion tank when the piston is moved from the home position to the actuated position and / or is positioned in the home position. Thus, a contacting unit is proposed that is characterized by particularly secure connection and disconnection of the charging contact with the charging port of the electric vehicle. Furthermore, the control device enables fully automatic control of the lifting device.

[0016] In one specific embodiment, the lifting device comprises a controllable valve device that blocks a flow path toward the slave cylinder in a blocking position and releases it in a release position. The control device is configured to move the valve device into the release position in an end position of the electric vehicle, whereby the charging contact can be or is moved into the charging position. In particular, the valve device functions to block the hydraulic path between the pressure accumulator and the slave cylinder when the vehicle is positioned on the ground and to release it when the vehicle is in the end position.Thus, the fluid volume displaced by the master cylinder is stored in the pressure accumulator when the valve device is in the locked position and directed toward the slave cylinder when the valve device is in the released position, whereby the charging contact is only transferred to the charging position when the vehicle is in the end position. Preferably, the control device is connected to the valve device via signaling and / or electrical means. Preferably, the valve device is designed as a 2 / 2-way valve, which is preferably closed in the basic position. Thus, a lifting device is proposed which enables a simple, targeted transfer of the charging contact to the charging position by means of the control device.

[0017] In a further specific embodiment, the lifting device comprises a further controllable valve device that blocks a flow path toward the expansion tank in a blocking position and releases it in a release position. The control device is configured to move the further valve device into the release position in an end position of the electric vehicle, so that the charging contact can be moved into the non-charging position. In particular, the further valve device has the function of releasing the hydraulic path toward the expansion tank when the vehicle is arranged in the end position and of blocking it when the vehicle is positioned on the ground.Thus, the fluid volume displaced by the slave cylinder is stored in the pressure accumulator when the valve device is in the locked position and directed toward the expansion tank when the vehicle is in the release position, thereby transferring the charging contact to the non-charging position when the vehicle is in the end position. Preferably, the control device is connected to the additional valve device via signaling and / or electrical means. Preferably, the additional valve device is designed as an additional 2 / 2-way valve, which is preferably closed in the basic position. Thus, a lifting device is proposed which enables a simple, targeted transfer of the charging contact to the non-charging position by means of the control device.

[0018] In a further specific implementation, the contacting unit comprises a rail arrangement that is designed and / or suitable for adapting the lifting device to a vehicle geometry of the electric vehicle. In particular, the rail arrangement serves to adapt the lifting device to a ground clearance and / or a track width and / or a wheelbase and / or a charging connection of the electric vehicle. Preferably, the rail arrangement can be used to compensate for parking inaccuracies by the driver in the horizontal direction. Thus, a lifting device is proposed that can be easily adapted to different vehicle geometries and is thus universally applicable.

[0019] According to this implementation, the rail arrangement has a first rail system via which the charging contact can be aligned with an underbody charging connection of the electric vehicle. In particular, the first rail system serves to set an initial position of the charging contact in a horizontal and / or vertical direction. Optionally, the first rail system additionally serves to float the charging contact in order to compensate for small parking tolerances between the charging contact and the charging connection during transfer into the charging position. In particular, the first rail system has at least one rail along which the charging contact is linearly guided in a vehicle longitudinal direction and / or in a vehicle transverse direction and / or vehicle vertical direction. The charging contact is preferably adjusted in the vertical direction to the ground clearance of the electric vehicle in the unloaded state.

[0020] Alternatively or optionally, the rail arrangement comprises a second rail system, via which the at least one master cylinder can be aligned to a track width of the electric vehicle. In particular, the second rail system serves to adjust a distance between the master cylinder, in particular the piston designed as a base plate, and the charging contact and / or between two master cylinders in a horizontal direction. In particular, the second rail system comprises at least one rail along which the at least one master cylinder is linearly guided in a vehicle longitudinal direction and / or in a vehicle transverse direction.

[0021] A further subject matter of the invention relates to a method for controlling the contacting unit according to one of the preceding claims, in which an electric vehicle is positioned or parked on a floor surface; a hydraulic actuating force is generated under the influence of the weight of the electric vehicle, preferably by the hydraulic lifting device; a charging contact is transferred from a non-charging position to a charging position as a function of the hydraulic actuating force, preferably by means of the hydraulic lifting device, and is contacted with a charging connection of the electric vehicle. In particular, the electric vehicle is arranged with at least one vehicle wheel on the base plate of the master cylinder, whereby the piston is transferred from the basic position to the actuating position and / or a fluid column is displaced from the master cylinder towards the slave cylinder.Preferably, the two valve devices are initially in the blocking position so that the fluid volume displaced by the master cylinder is stored in the pressure accumulator. When the electric vehicle reaches an end position, the valve device assigned to the slave cylinder is moved into the release position, whereby the fluid volume located in the pressure accumulator is at least partially displaced into the slave cylinder and the charging contact is moved into the charging position. In order to move the charging contact back into the non-charging position under the influence of weight, the valve device assigned to the expansion tank is moved into the release position, whereby the fluid volume located in the slave cylinder is at least partially displaced into the expansion tank and the charging contact is moved into the non-charging position.After removing the electric vehicle, the piston of the master cylinder is returned to the basic position, whereby the fluid volume in the expansion tank is at least partially displaced or sucked into the master cylinder and is available again for further actuation.

[0022] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. It shows:

[0023] Fig. 1 shows a schematic representation of a contacting unit for an underbody charging station in a first embodiment; Fig. 2 shows the contacting unit in the same representation as shown in Fig. 1 in a second embodiment;

[0024] Fig. 3 the contacting unit in a schematic plan view.

[0025] Figure 1 shows a schematic representation of a contacting unit 1 for an underbody charging station for electrically charging an energy storage device of an electric vehicle 2, indicated only schematically, as one exemplary embodiment of the invention. The contacting unit 1 is arranged underneath the electric vehicle 2 and serves to contact an underbody charging connection 3 of the electric vehicle 2.

[0026] The contacting unit 1 has a charging contact 4, which, in a charging position 100, as shown in Figure 1, is conductively or inductively connected to the underbody charging connection 3. The charging contact 4 is permanently connected via a supply line 5 to a power source, via which the charging contact 4 can be supplied with electrical energy. For example, the charging contact 4 and the underbody charging connection 3 are connected to one another via a plug connection (not shown in detail), wherein a charging process of the energy storage device can be carried out via the plug connection.

[0027] The contacting unit 1 has a hydraulic lifting device 7, which, under the influence of a weight force 102 of the electric vehicle 2, preferably a wheel load, generates a hydraulic actuating force 103 in order to transfer the charging contact 4 from a non-charging position 101 to the charging position 100. For this purpose, the contacting unit 1 comprises a height-adjustable boom 6 on which the charging contact 4 is mounted. The hydraulic lifting device 7 is motion-coupled to the boom 6 in order to translate the hydraulic actuating force 103 into a vertical lifting movement between the charging and non-charging positions 100, 101. The hydraulic lifting device 7 essentially comprises a master cylinder 8 and a slave cylinder 9, which are fluidly connected to one another via a hydraulic path 10, wherein, under the influence of the weight force 102, a fluid column is displaced from the master cylinder 8 towards the slave cylinder 9.The master cylinder 8 has a cylinder housing 11 and a piston 12 designed as a base plate and displaceable within the cylinder housing 11, which together define a pressure chamber 13 filled with a hydraulic fluid. In an end position, the vehicle 2 rests with at least one vehicle wheel 14 on a piston surface 15 of the piston 12, wherein the piston surface 15 is larger than a wheel contact area 16, in particular a tire contact area, of the vehicle wheel 14. Thus, the weight force 102 is introduced directly into the piston 12 across the entire wheel contact area 16, whereby the piston 12 is transferred from a basic position 104 to an actuated position 105 and a fluid volume is displaced.In order to return the piston 12 to the home position 104 in the unloaded state, the master cylinder 8 has a return device 17 arranged within the pressure chamber 13, which applies a return force 106 to the piston 12 acting counter to the weight force 102. For example, the return device 17 is designed as a disc spring or a disc spring assembly.

[0028] The lifting device 7 has a pressure accumulator 18, which is fluidically integrated into the hydraulic line 10 between the master cylinder 8 and the slave cylinder 9. Upon actuation of the master cylinder 8, a fluid pressure is generated or increased, which fills the pressure accumulator 18. In other words, the fluid volume displaced by the piston 12 in the actuated position 105 is shifted or temporarily stored in the pressure accumulator 18. For example, the pressure accumulator 18 is designed as a spring-loaded accumulator.

[0029] The lifting device 7 has a controllable valve device 19, which is integrated into the hydraulic line 10 between the pressure accumulator 10 and the slave cylinder 9. In a blocking position, the valve device 19 blocks a flow path toward the slave cylinder 9 and releases it in a release position. In this case, the valve device 19 is initially switched to the blocking position, so that when the electric vehicle 2 is positioned on the piston surface 15 in the direction of the slave cylinder 9, the flow path is blocked and the pressure accumulator 18 is filled first.

[0030] The contacting unit 1 has a control device 20, which is configured to control the valve device 19 depending on a vehicle position. For this purpose, the control device 20 can communicate with the vehicle 2 and / or a corresponding sensor system, e.g., a light barrier, via a data network 21 in order to obtain the current vehicle position. If the vehicle 2 is in a predetermined end position, a control signal is transmitted by the control device 20 to the valve device 19, and the valve device 19 is switched to the release position. The now relaxing pressure accumulator 18 displaces the stored fluid volume toward the slave cylinder 9, which in turn transmits the hydraulic actuating force 103 to the boom 6 via at least one pivot arm 22.

[0031] The pivot arm 22 is connected, on the one hand, in an articulated manner to a piston rod 23 of the slave cylinder 9 and, on the other hand, in an articulated manner to the boom 6. A movement of the piston rod 23 in the horizontal direction is translated via the pivot arm 22 into a movement of the boom 6 in the vertical direction toward the vehicle 2 or an underbody of the electric vehicle 2. The charging contact 4 is now moved upwards from the non-charging position 101 to the charging position 100 and connected or operatively connected to the charging port 3. The charging process can now begin.

[0032] Furthermore, the lifting device 7 has a throttle 24, which is fluidically integrated into the hydraulic line 10 between the valve device 19 and the slave cylinder 9. The throttle 24 serves to throttle the flow path toward the slave cylinder 9, so that the slave cylinder 9 is filled only slowly and a sudden transfer of the charging contact 4 from the non-charging position 101 to the charging position 100 is prevented. This can prevent damage to the charging contact 4 or the charging connection 3.

[0033] The lifting device 7 has a compensating tank 25, which is fluidically integrated into the hydraulic line 10 between the pressure accumulator 18 and the master cylinder 8. The compensating tank 25 serves to absorb a fluid volume displaced by the slave cylinder 9 when the charging contact 4 is moved from the charging position 100 to the non-charging position 101 and the piston 12 of the master cylinder 8 is in the actuating position 105 or is loaded by the weight force 102.

[0034] For this purpose, the lifting device 7 has a further controllable valve device 26, which is integrated between the pressure accumulator 10 and the slave cylinder 9 into the hydraulic line 10 upstream of the expansion tank 25. In a blocking position, the further valve device 26 blocks a flow path toward the expansion tank 25 and releases it in a release position. In this case, the valve device 26 is initially switched to the blocking position, so that when the electric vehicle 2 is positioned on the piston surface 15, a flow path toward the expansion tank 25 is blocked and the pressure accumulator 18 is filled.

[0035] The control device 20 is configured to control the additional valve device 26 depending on a vehicle state. For this purpose, the control device 20 can communicate with the vehicle 2 via a data network 21 in order to obtain the current vehicle state. For example, when the electric vehicle 2 is started and / or when the charging process is terminated, a control signal is transmitted by the control device 20 to the additional valve device 26, and the additional valve device 26 is switched to the release position. The now relaxing slave cylinder 9 displaces the fluid volume toward the compensation tank 25, thereby reducing the hydraulic actuating force 103 and lowering the boom 6 vertically into the non-charging position 101. The vehicle 2 is free and can be moved away.After the master cylinder 8 is relieved of pressure, the piston 12 is returned to the home position 104 via the return device 17, thereby sucking the corresponding volume of fluid from the expansion tank 25, which is required for the next actuation. Finally, the two valve devices 19, 26 are switched back to the blocking position, so that the lifting device 7 is ready for the next charging process. In summary, a contacting unit 1 is proposed in which the vehicle 2 drives onto the master cylinder 8, wherein the master cylinder 8 is actuated by the wheel load provided by the vehicle 2, and the fluid displaced thereby hydraulically moves the charging contact 4 into the charging position 100 or connects it to the charging port 3 of the electric vehicle 2.

[0036] The contact unit 1 is designed so that it can only be used once per drive-up of the electric vehicle 2. If the charging contact 4 has been moved from the charging position 100 to the non-charging position 101, for example due to a user interruption, while the weight force 102 continues to act on the piston 12, the vehicle 2 must be removed so that the lifting device 7 is ready to reconnect the charging contact 4 to the charging port 3.

[0037] Thus, a contact unit 1 is proposed that automatically establishes an electrical connection between the charging station and the vehicle 2, without the driver having to physically connect the charging station with a cable. Furthermore, thanks to the hydraulic lifting device 7, the contact unit 1 can be implemented particularly cost-effectively and without the need for additional actuators.

[0038] Figure 2 shows an alternative embodiment of the lifting device 7, in particular of the master cylinder 8, wherein instead of filling the pressure chamber 13 with the hydraulic fluid, a hydraulic membrane 27 is arranged in the pressure chamber 13, upon which the piston 12 acts. This eliminates the need to seal the piston 12 from the cylinder housing 11. Figure 3 shows the contacting unit 1 in a schematic plan view, wherein the contacting unit 1 in the embodiment shown has two of the master cylinders 8, via each of which the wheel load of a vehicle wheel 14, e.g., two front wheels, can act as a weight force 102. The contacting unit 1 has a rail arrangement 28, which serves to adjust the contacting unit 1 to the geometry of the vehicle 2 used.The contacting unit 1 can be adapted to the vehicle geometry via the rail arrangement 28 both in terms of width and in the position of the boom 6.

[0039] The rail arrangement 28 has a first rail system 29, via which the charging contact 4 can be aligned with an underbody charging connection 3 of the electric vehicle 2, as described in Figure 1. For example, the charging contact 4 can be adjusted via the first rail system 29 in a horizontal direction, in particular a vehicle longitudinal direction 107 and / or a vehicle transverse direction 108, and / or in a vertical direction, in particular in a vehicle vertical direction 109, as indicated in Figure 1. For example, the first rail system 29 can each have a rail, not shown in detail, along which the boom 6 is guided straight in the respective direction. The boom 6 or the charging contact 4 is set to the "unloaded vehicle" state. Thus, the boom 6 can reach its maximum required height in the vehicle vertical direction 109 in the charging position 100. If the vehicle 2 is loaded, this results in a higher pressure ora remaining residual fluid in the pressure accumulator 18.

[0040] Furthermore, the rail arrangement 28 has a second rail system 30, via which the two master cylinders 8 or their pistons 12 designed as base plates can be adapted to a track width of the electric vehicle 2. For example, the two master cylinders 8 can be adjusted via the second rail system 29 in a horizontal direction, in particular a vehicle transverse direction 108, in order to set a distance between the two master cylinders 8 or a distance to the charging contact 4. For example, the second rail system 30 can have at least one rail, not shown in detail, along which the two master cylinders 8 are guided in a straight line in the vehicle transverse direction 108. Thus, a contacting unit 1 is proposed which dispenses with the installation of expensive sensors and can be easily adapted to different vehicle geometries.Once the contact unit 1 has been set up, the charging port 3 of the electric vehicle 2 can then be securely connected.

[0041] List of reference symbols

[0042] Contacting unit

[0043] electric vehicle

[0044] Underbody charging connection

[0045] Charging contact

[0046] supply line

[0047] Boom hydraulic lifting device master cylinder

[0048] Slave cylinder hydraulic line cylinder housing

[0049] Pistons

[0050] Print room

[0051] vehicle wheel

[0052] Piston area

[0053] Wheel contact area

[0054] Reset device

[0055] Pressure accumulator controllable valve device control device

[0056] data network

[0057] Swivel arm

[0058] piston rod

[0059] throttle

[0060] Expansion tank further controllable valve device hydraulic diaphragm rail arrangement first rail system second rail system loading position non-loading position weight hydraulic actuating force basic position confirmation position restoring force vehicle longitudinal direction vehicle transverse direction vehicle vertical direction

Claims

Patent claims 1. Contact unit (1) for a charging station for electrically charging an electric vehicle (2), - with a charging contact (4) which is at least adjustable in height for contacting a charging connection (3) of the electric vehicle (2), - with a lifting device (7) which is movement-coupled to the charging contact (4) and which is designed to move the charging contact (4) between a charging and a non-charging position (100, 101), characterized in that the lifting device (7) is a hydraulic lifting device (7) which is designed to generate a hydraulic actuating force (103) under the action of a weight force (102) of the electric vehicle (2) in order to transfer the charging contact (4) from the non-charging position (101) into the charging position (100).

2. Contacting unit (1) according to claim 1, characterized in that the lifting device (7) has a master cylinder (8) which can be actuated by the weight force (102) and a slave cylinder (9) which is coupled in movement to the charging contact (4), which are fluidically connected to one another via a hydraulic path (10), wherein under the action of the weight force (102) a fluid column can be displaced from the master cylinder (8) in the direction of the slave cylinder (9) in order to transfer the charging contact (4) from the non-charging position (101) into the charging position (100).

3. Contacting unit (1) according to claim 2, characterized in that the master cylinder (8) has a piston (12) designed as a base plate, the piston surface (15) of which corresponds to at least one wheel contact surface (16) of at least one vehicle wheel (14) of the electric vehicle (2).

4. Contacting unit (1) according to claim 2 or 3, characterized in that the lifting device (7) has a pressure accumulator (18) which is fluidically integrated into the hydraulic path (10) between the master cylinder (8) and the slave cylinder (9) in order to absorb, in whole or in part, a quantity of fluid displaced by the master cylinder (8).

5. Contacting unit (1) according to one of the preceding claims, characterized in that the lifting device (7) has a compensating container (25) which is fluidically integrated into the hydraulic path (10) between the master cylinder (8) and the slave cylinder (9) in order to completely or partially absorb a quantity of fluid displaced by the slave cylinder (9).

6. Contacting unit (1) according to one of the preceding claims, characterized by a control device (20) which is designed to control the lifting device (7) as a function of a vehicle position and / or a vehicle state.

7. Contacting unit (1) according to claim 6, characterized in that the lifting device (7) has a controllable valve device (19) which blocks a flow path in the direction of the slave cylinder (9) in a blocking position and releases it in a release position, wherein the control device (20) is designed to transfer the valve device (19) in an end position of the electric vehicle (2) into the release position, whereby the charging contact (4) can be transferred into the charging position (100).

8. Contacting unit (1) according to claim 5 and 6, characterized in that the lifting device (7) has a further controllable valve device (26) which blocks a flow path in the direction of the compensation tank (25) in a blocking position and releases it in a release position, wherein the control device (20) is designed to transfer the further valve device (26) into the release position in an end position of the electric vehicle (2) so that the charging contact (4) can be transferred into the non-charging position (101).

9. Contacting unit (1) according to one of the preceding claims, characterized by a rail arrangement (28) for adapting the lifting device (7) to a vehicle geometry of the electric vehicle (2), wherein the rail arrangement (28) has a first rail system (29) via which the charging contact (4) can be aligned with an underbody charging connection (3) of the electric vehicle (2), and / or a second rail system (30) via which the at least one master cylinder (8) can be aligned with a track width of the electric vehicle (2).

10. Method for controlling the contacting unit (1) according to one of the preceding claims, in which: - an electric vehicle (2) is positioned on a floor surface; - a hydraulic actuating force (103) is generated under the action of a weight force (102) of the electric vehicle (2); - a charging contact (4) is transferred from a non-charging position (101) to a charging position (100) as a function of the hydraulic actuating force (103) and is contacted with a charging connection (3) of the electric vehicle (2).

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