drive device

Abstract

Drive device (1) for opening and closing a pivoting vehicle flap (VF), comprising an outer casing (2) with a longitudinal axis (A), which outer casing (2) has a first end (2a) and a second end (2b) opposite the first end (2a), an electromagnetic linear motor (3) comprising a stator (4) and a rod-shaped lifting element (5) displaceable along the longitudinal axis (A) with a first end (5a) and with a second end (5b) opposite the first end (5a), wherein the lifting element (5) can be extended telescopically from the outer housing (2) and can be retracted telescopically into the outer housing (2), wherein the lifting element (5) and the stator (4) can be coupled to each other at least section by means of a magnetic coupling (13), wherein the outer housing (2) comprises an inner housing (7) with a gas spring (8), wherein the gas spring (8) has a pressurized pressure chamber (10) filled with a fluid (9), wherein the fluid (9) exerts a pressure force on the lifting element (5), characterized in that that the pressure chamber (10) and the electromagnetic linear motor (3) are fluid-tightly separated from each other.

Description

[0001] The present invention relates to the field of electrical actuators and concerns a drive device for opening and closing a pivotable flap of a vehicle according to the preamble of claim 1.

[0002] Electrically driven actuators, such as spindle drives, are known in practice for opening and closing a pivoting vehicle flap, and these actuators typically include a helical compression spring. The helical compression spring is usually made of a steel alloy. In this configuration, the helical compression spring is generally pre-tensioned in the opening direction of the vehicle flap within the actuator housing. This compressed arrangement of the helical compression spring in the actuator housing is referred to as the initial position, whereby potential energy of the compressed helical compression spring is stored in the actuator housing.

[0003] The helical compression spring assists in the opening movement of a vehicle flap, such as a tailgate, thus eliminating the need for costly, energy-intensive electric motors. This allows for the use of less powerful and more compact electric motors in the drive mechanism. When the flap closes, its own weight partially acts on the helical compression spring. This weight compresses the spring, allowing it to return to its original position within the drive mechanism housing.

[0004] A problem with commercially available drive units is the complex installation of the helical compression spring into the drive unit housing during production. Furthermore, existing drive units with integrated helical compression springs tend to generate unwanted noises, such as clicking and / or rattling, when the vehicle hatch is opened or closed. These noises, caused by the helical compression spring, can arise, for example, from lateral displacement of the spring within the drive unit housing under load.

[0005] Furthermore, gas spring-assisted drive devices are known from practice that completely eliminate the use of helical compression springs, particularly for the reasons mentioned above. In these devices, the helical compression spring is replaced by an inert gas, such as nitrogen, within the drive device housing. However, a problem with commercially available gas spring-assisted drive devices is the sealing, especially of moving components. Another disadvantage is that a gas spring exhibits varying actuating and holding forces depending on the ambient temperature.

[0006] DE 10 2004 008 411 A1 discloses a drive device for opening and closing a pivoting vehicle hatch, comprising an outer housing with a longitudinal axis, the outer housing having a first end and a second end opposite the first end. The drive device further comprises an electromagnetic linear motor, comprising a stator and a lifting element displaceable along the longitudinal axis, having a first end and a second end opposite the first end, the lifting element being telescopically extendable from the outer housing and telescopically retractable into the outer housing, the lifting element and the stator being at least partially couplingable to each other via a magnetic coupling, and a gas spring being located in the outer housing, the gas spring having a pressurized pressure chamber filled with a fluid.A disadvantage here is that the electromagnetic linear motor is at least partially in contact with the pressurized fluid. This can, for example, lead to a more difficult and time-consuming assembly of the drive device.

[0007] EP 3 306 798 A1 describes a mode of operation of an electromagnetic linear motor, which electromagnetic linear motor has a stator which is designed as a tubular coil set, wherein a lifting element can be linearly displaced relative to the stator by means of a magnetic coupling.

[0008] Therefore, there is a need for a robust and quiet gas spring-assisted drive device that solves the sealing problem in particular, thereby ensuring an increased product lifespan of the gas spring-assisted drive device.

[0009] The present invention is therefore based on the technical problem of providing an improved drive device for opening and closing a pivoting flap of a vehicle, which drive device is reliable, compact and quiet.

[0010] According to the invention, this problem is solved by a drive device according to claim 1.

[0011] Further advantageous embodiments are specified in the dependent claims.

[0012] According to the invention, a drive device for opening and closing a pivoting vehicle flap is provided, comprising an outer housing with a longitudinal axis, which outer housing has a first end and a second end opposite the first end.Furthermore, the drive device comprises an electromagnetic linear motor, including a stator and a rod-shaped lifting element displaceable along the longitudinal axis, having a first end and a second end opposite the first end. The lifting element is telescopically extendable from and retractable into the outer housing. The lifting element and the stator are at least partially couplingable to each other via a magnetic coupling. The outer housing comprises an inner housing with a gas spring, the gas spring having a pressurized pressure chamber filled with a fluid, the fluid exerting a pressure force on the lifting element. The drive device is characterized by the fact that the pressure chamber and the electromagnetic linear motor are fluid-tightly separated from each other.Advantageously, the electromagnetic linear motor has no contact with the pressurized fluid, which significantly simplifies assembly and functional testing of the drive unit. Furthermore, the drive unit has a longer service life because sensitive components such as electrical contacts, cables, etc., do not come into contact with the fluid, thus eliminating the need for complicated and costly cable routing for pressure vessels. Another advantage is that the relatively large inner circumference of the housing provides a larger surface area at the bottom for the compressed fluid to act upon, enabling the generation of higher pressure forces to reliably open a vehicle hatch. Finally, the overall number of components in the drive unit is advantageously reduced, as is the number of moving parts.The number of rotating components is reduced to a minimum, enabling quiet operation while simultaneously allowing relatively high forces to be generated by the drive device. This results in a compact, reliable, and quiet drive device.

[0013] In this context, a fluid is a gas, a liquid, or a supercritical fluid. Furthermore, any mixture or solution of the aforementioned media is also considered a fluid, and these mixtures and solutions are likewise grouped under the general term "fluid." Additionally, the fluid may contain other solids, such as particles.

[0014] Advantageously, the stator is designed as a tubular coil assembly comprising several coils. The stator's compact design is beneficial, resulting in a small installation volume. Furthermore, the stator allows the generation of specific magnetic fields capable of completely surrounding at least a portion of the lifting element. These are linearly migrating magnetic fields, generated by a defined electrical current. The electrical current supplied to excite the stator is finely controllable and adjustable to generate a defined, linearly migrating magnetic field. For example, a coil might have a three-phase winding, which is excited by a three-phase AC power supply.It is therefore possible to generate at least one magnetic field via a controllable and adjustable AC power supply. This magnetic field has a defined north-south orientation and can oscillate back and forth between a first end of the stator and a second end opposite it. The stator thus generates the required switchable driving magnetic force of a linear electric motor by regulating the power supply. The controllability of the electromagnetic linear motor advantageously opens up the possibility of automating the drive system.

[0015] According to an alternative embodiment, the stator comprises a coil for generating a magnetic field with a plurality of turns, wherein the lifting element has an armature made of a magnetizable material that can be arranged in the magnetic field and which armature can be deflected by the magnetic field of the coil. This configuration is advantageously preferred when space is limited. Furthermore, this configuration is simple and cost-effective.

[0016] Preferably, the stator has an inner circumference that defines an opening. This allows for the advantageous generation of a homogeneous magnetic field, while the stator has a compact design, thus facilitating its installation in the outer housing.

[0017] Advantageously, the lifting element is arranged at least partially within the opening of the stator, and is displaceable relative to the stator along its longitudinal axis. The lifting element is advantageously surrounded at least partially by the stator, so that the generated magnetic field can act on the lifting element from the adjacent stator. This generates a repulsive or attractive magnetic force via the stator, allowing the lifting element to be displaced in a specific direction along its longitudinal axis.

[0018] Advantageously, the lifting element incorporates a multitude of magnets. The driving repulsive or attractive magnetic force of the electromagnetic linear motor is advantageously amplified by arranging permanent magnets within the lifting element with a defined north-south orientation. This results in the lifting element exhibiting both a higher adjustment force and a higher holding force, thus enabling vehicle hatches with increased weight to be moved in a defined manner and held in an open position.

[0019] Preferably, the magnets are arranged in series along the longitudinal axis of the lifting element, adjacent to one another. To prevent undesired slippage of the lifting element, which would prevent it from being driven or moved as desired, the magnets are arranged close together along the longitudinal axis of the lifting element. Advantageously, this creates a magnetic coupling between the lifting element and the stator, which exhibits the same repulsive or attractive magnetic force at any point along the lifting element. In this way, a movable lifting element is provided to the drive device, possessing a defined actuation force and capable of precise movement.

[0020] Preferably, the magnets are encased by an outer surface of the lifting element. Inside the lifting element, the magnets form a core, which is reliably protected from external influences, such as weather conditions. Furthermore, the magnets are secured against falling out of the lifting element.

[0021] In a particularly preferred embodiment, a rigid guide tube is arranged in the inner housing. This guide tube has a first end and a second end opposite the first end, and is arranged coaxially with respect to the longitudinal axis. The guide tube advantageously serves to support and guide the lifting element, enabling the lifting element to be extended and retracted from the outer housing reliably and without tilting.

[0022] Preferably, the lifting element has a cylindrical sealing element at its first end, which sealing element is arranged inside the guide tube and is displaceable relative to the guide tube. The sealing element has a first side and a second side facing away from the first side, with preferably only the first side of the sealing element being in contact with the pressurized fluid. Advantageously, the sealing element inside the guide tube prevents the pressurized fluid from coming into contact with the electromagnetic linear motor.

[0023] Overall, it is advantageous that the lifting element can be arranged at least partially within the guide tube and that the lifting element can be moved relative to the guide tube. This advantageously ensures reliable support and guidance of the lifting element via the guide tube in a simple manner, thus preventing unwanted tilting of the lifting element during repositioning.

[0024] Preferably, the cylindrical sealing element is designed as a dynamic piston seal assembly with at least one piston seal, which forms a fluid seal against an inner surface of the guide tube. Because the sealing element is reciprocally movable, it advantageously features a durable dynamic piston seal. This provides a reliable and long-lasting drive device.

[0025] In a preferred embodiment, the lifting element and the stator are arranged coaxially with respect to the longitudinal axis. This advantageously creates a compact drive device. Furthermore, the electromagnetic linear motor of the drive device is characterized by efficiency and precision due to the above arrangement.

[0026] Advantageously, the outer and inner housings form an annular gap, which is fluid-tight and separated from the pressure chamber. The rigid, pressurized inner housing is located inside the outer housing, thus ensuring increased safety in the event of an unintended rupture of the inner housing. In the event of a rupture, the fluid can escape in a controlled manner through the annular gap and the through-hole in the outer housing. Accordingly, the drive device features a simple and effective safety concept for pressurized containers. In particular, in the event of an unintended rupture of the inner housing, only the inner housing would need to be replaced.

[0027] According to an advantageous embodiment, an electrical cable is arranged within the annular gap. The annular gap advantageously provides additional space, allowing electrical cables and other electrical or electronic components to be arranged in a pressure-free environment to reliably supply the electromagnetic linear motor with current and voltage. Furthermore, it is possible to arrange measuring sensors, such as temperature sensors, accelerometers, and / or a gyroscope, within the annular gap.

[0028] Advantageously, a first adapter part and a corresponding second adapter part are arranged in the inner housing, wherein the first adapter part and the second adapter part rest complementarily on each other at their end faces, and wherein at least one static sealing element is arranged between the first adapter part and the second adapter part. The first adapter part and the second adapter part advantageously form a static sealing system together with the static sealing element, which prevents the pressurized fluid from coming into contact with the electromagnetic linear motor. Furthermore, the first adapter part and the second adapter part serve as a centering and bearing element, so that the guide tube, the lifting element, and the stator are aligned coaxially with respect to the longitudinal axis.

[0029] It is particularly preferred that the first and second adapter parts are connected to each other via a plug-in connection to prevent rotation. The first adapter part has at least one recess on an end face facing the second adapter part. The second adapter part has at least one projection on an end face facing the first adapter part. The recess of the first adapter part and the projection of the second adapter part are complementary and can be plugged into each other. Advantageously, both end faces of the first and second adapter parts lie parallel to each other, so that a static sealing element arranged between the first and second adapter parts is fluid-sealed.

[0030] Furthermore, a rotationally secured plug connection is advantageously provided between the second adapter part and the outer housing, wherein one side of the second adapter part, which faces an inner base of the outer housing, has at least one recess. The inner base of the outer housing has a projection complementary to the recess, so that the recess and the projection of the inner base can be plugged into each other. This ensures reliable support of the stator and guidance of the lifting element.

[0031] Advantageously, a simple plug-in connection prevents any twisting around the longitudinal axis of the first and second adapter parts relative to the outer housing. This anti-rotation arrangement is particularly important for the connected electrical cables and contacts to the stator, preventing them from being unintentionally torn off. Furthermore, assembly is intuitive and easy thanks to the plug-in elements of the first and second adapter parts. It goes without saying that plug-in elements such as protrusions and recesses are interchangeable.

[0032] Preferably, the outer housing has a first connection element at its first end, and preferably, the outer housing has a through-opening at its second end for the movable lifting element. The first connection element is, for example, a ball socket or a ball head, and advantageously, a hinged connection of the first connection element to one of the vehicle frame and the vehicle hatch is provided. The through-opening advantageously serves for the support and precise guidance of the lifting element in order to reliably open and close a vehicle hatch.

[0033] In a preferred embodiment, the first connecting element is bonded to the outer housing. A bonded connection, e.g., a weld or adhesive bond, advantageously prevents unintentional disassembly or removal of the first connecting element from the outer housing under tensile forces. This provides a robust and reliable drive device.

[0034] Preferably, the lifting element has a second connection element at its second end. The second connection element is, for example, a ball socket or a ball head, and advantageously, a hinged connection of the second connection element to the other of the vehicle frame and vehicle flap is provided.

[0035] It is particularly preferred that the current to the stator can be regulated via a control unit. Advantageously, the control unit can be used not only to change the direction of the current flowing through the coil or coil set, but also the strength of the generated magnetic field. This makes the drive device advantageously adaptable for different flaps with varying weights and pivoting movements.

[0036] According to an advantageous embodiment, a defined position of the lifting element can be detected by means of sensors. The distance traveled by the lifting element in both directions can advantageously be determined precisely using so-called position sensors. Alternatively or additionally, limit switches are provided at defined positions along the longitudinal axis, which indicate the position of the lifting element.

[0037] Advantageously, the stator is arranged in a sealed position within the inner housing, in a region near the second end of the outer housing. The stator and its sensitive electrical components, such as contact elements and cables, are advantageously kept out of contact with the pressurized fluid. Furthermore, the stator is compactly and space-efficiently integrated within the inner housing.

[0038] Preferably, the lifting element is designed as a hollow body with an inner surface, wherein the inner surface of the lifting element is free from the pressurized fluid in the pressure chamber. The lifting element advantageously has a low weight, thereby reducing the overall weight of the drive device. Furthermore, the lifting element can be manufactured cost-effectively.

[0039] Preferably, the lifting element is made of a plastic. Because a pressure-free space always prevails within the lifting element, it can be advantageously manufactured from plastic using an injection molding process, thus saving costs.

[0040] The inner casing is advantageously made of an aluminum alloy or steel. The inner casing encloses the pressure chamber, which is under increased pressure, higher than the ambient pressure of approximately 1 bar. To withstand the stress caused by the internal pressure, the inner casing is designed to be made of a metal such as stainless steel or an aluminum alloy. A wall thickness of approximately 2 mm to 5 mm is advantageous to ensure protection against rupture. The design and calculation of pressure vessels are carried out, for example, using the AD 2000 code.

[0041] Further features and advantages of the present invention will become apparent from the following drawings and embodiments, which serve to explain the invention in more detail by way of example, without limiting the invention to these.

[0042] The invention is explained in more detail below with reference to the accompanying drawings. Fig. Figure 1 shows a sectional view of a preferred embodiment of a drive device according to the invention in an extended position (position position). Fig. 2 shows an enlarged view II from Fig. 1. Fig. Figure 3 shows a sectional view of the embodiment of the drive device according to the invention. Fig. 1 in a locked position (starting position). Fig. Figure 4 shows an enlarged view of IV from Fig. 3. Fig. Figure 5 shows an enlarged view of V from Fig. 3.

[0043] Fig. Figure 1 shows a sectional view along a longitudinal axis A of a preferred embodiment of a gas spring-assisted drive device 1 with an integrated electromagnetic linear motor 3 for opening and closing a vehicle hatch VF. The drive device 1, which has a first end 1a and a second end 1b opposite the first end 1a, is shown in a position extended in the displacement direction x.

[0044] The drive device 1 is designed as a gas spring-assisted, linearly electromagnetically driven actuator for opening and closing a pivoting flap VF of a vehicle. Furthermore, the drive device 1 has a hollow cylindrical outer housing 2 in which a hollow cylindrical inner housing 7 is arranged. The longitudinal axis A also coincides with a central axis of the drive device 1.

[0045] The drive device 1 further comprises a first connecting element 23 designed as a first ball socket and a second connecting element 24 designed as a second ball socket opposite the first connecting element 23.

[0046] The hollow cylindrical outer housing 2 further comprises a first end 2a and a second end 2b opposite the first end 2a, with a through-opening 25. A movable lifting element 5 is linearly movable through the through-opening 25 relative to the outer housing 2, the through-opening 25 of the outer housing 2 serving as a guide and bearing element for the lifting element 5.

[0047] In this embodiment, the first connecting element 23 is pivotally coupled to a vehicle frame VB of a vehicle, and the second connecting element 24, opposite the first connecting element 23, is pivotally coupled to a pivotable vehicle flap VF or vehicle door of the vehicle. For clarity, the vehicle frame VB and the vehicle flap VF are shown schematically as dashed lines. The drive device 1 preferably serves to open, hold, and close the vehicle flap VF or vehicle door of the vehicle. For clarity, a vehicle is not shown.

[0048] Furthermore, the drive device 1 comprises an electromagnetic linear motor 3, comprising a stator 4 and the rod-shaped lifting element 5, which is displaceable along the longitudinal axis A and which lifting element 5 is preferably cylindrical. The lifting element 5 also has a first end 5a and a second end 5b opposite the first end 5a, to which the second connecting element 24 is connected via a screw connection.

[0049] As in Fig. As can be seen in Figure 1, the lifting element 5 can be extended telescopically from the outer housing 2 through the through-opening 25 to reach an active positioning position of the drive device 1. Furthermore, the lifting element 5 can be retracted telescopically into the outer housing 2 to return to a resting starting position of the drive device 1, as shown in Figure 1. Fig. Figure 3 shows that the lifting element 5 and the stator 4 can be coupled to each other via a switchable magnetic coupling 13, so that a first repulsive or attractive magnetic force required for the displacement of the lifting element 5 is provided by the electromagnetic linear motor 3.

[0050] The stator 4 is designed as a tubular coil assembly with a first end 4a and a second end 4b opposite the first end 4a. Furthermore, the stator 4 has a through opening 11 with an inner circumference 4c, in which the lifting element 5 is displaceably arranged. The stator 4 and the lifting element 5 are thus arranged coaxially with respect to the longitudinal axis A in the outer housing 2 and the inner housing 7, respectively. The electromagnetic linear motor 3 therefore essentially comprises two components: a stationary part, here referred to as the stator 4, and a movable part, which here is referred to as the lifting element 5.

[0051] As in Fig. Figure 2, shown enlarged, shows that the lifting element 5 has at least one permanent magnet 12 below an outer surface 6 of the lifting element 5. Because the stator 4 can be excited by means of an adjustable power supply, a linearly traveling magnetic field with a defined north-south orientation can be generated. The linearly traveling magnetic field exerts a repulsive force on the permanent magnet 12 due to the fact that like magnetic poles NN and SS repel each other and unlike magnetic poles NS and SN attract each other. In this way, the lifting element 5 is oriented according to the equation shown, using like magnetic poles NN and SS. Fig. The lifting element 5 is displaced outwards in one direction. To move the lifting element 5 back towards its initial position, the stator 4 is reversed, generating an attractive force via unequal magnetic poles NS and SN. This attractive force allows the lifting element 5 to be moved back into the outer housing 2. The strength of the magnetic field generated by the stator 4 depends on the current and / or voltage supply. Furthermore, the current and / or voltage supply to the stator 4 is controllable and adjustable, enabling the generation of a precisely defined magnetic field to ensure reliable adjustability of the lifting element 5. An electrical cable 19 required for the current and / or voltage supply of the electromagnetic linear motor 3 is arranged in a pressure-free annular gap 18, which is formed between the outer housing 2 and the inner housing 7.

[0052] The rigid, immobile hollow cylindrical inner housing 7 further comprises a gas spring 8. In addition to the magnetic force emanating from the electromagnetic linear motor 3, the gas spring 8 provides a further actuating force for the outward displacement of the lifting element 5. The gas spring 8 comprises a pressurized pressure chamber 10 filled with a fluid 9. Here, and preferably, the fluid 9 contains predominantly gaseous nitrogen, with the pressurized pressure chamber 10 being in Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Figure 5 is schematically represented by several circular symbols. The amount of fluid 9 filled into the pressure chamber 10 always remains constant, while the internal volume of the pressure chamber 10 changes due to the displacement of the lifting element 5.

[0053] In the retracted starting position of the drive device 1 according to Fig. 3 The fluid 9 is arranged in a compressed state predominantly in an annular gap 10a between the inner housing 7 and a hollow cylindrical guide tube 14, wherein the fluid 9 is fluidically connected via a pressure equalization channel of an alignment element 26 and can flow freely through the pressure equalization channel, so that a homogeneous pressure in the pressure chamber 10 can be quickly set. In the retracted starting position according to Fig. 3. The drive device 1 has a higher potential energy due to the fluid 9 compressed in the pressure chamber 10 compared to the extended position of the drive device 1 according to Fig. 1, since in the extended position of the drive device 1 the internal volume of the pressure chamber 10 is larger than the internal volume of the pressure chamber 10 in the starting position.

[0054] In the extended position of the drive device 1 according to Fig. 1. The fluid 9 is in an expanded state, with the fluid 9 remaining in the annular gap 10a between the inner housing 7 and the guide tube 14. Furthermore, the fluid 9 flows in the extended position of the drive device 1 according to Fig. 1 also into the guide tube 14, so that the fluid 9 can spread almost throughout the entire inner housing 7. In the extended position, due to the increase in the internal volume of the pressure chamber 10 caused by the expanded fluid 9, the drive device 1 thus has a reduced potential energy.

[0055] The pressure in the compressed state is according to Fig. 3 of the drive device 1 preferably between 10 bar and 230 bar, wherein a pressure here and preferably is about 80 bar at an ambient temperature of 25°C (standard temperature) according to the retracted starting position of the drive device 1 shown in Fig. 3.

[0056] Furthermore, the pressure in the pressure chamber 10 depends on the ambient temperature due to the material properties of the fluid 9, with a temperature range between -30°C and +80°C being considered an operating range for the drive device 1. Within this operating range, at an ambient temperature between -30°C and +80°C, the pressure increases by approximately 3% to 4% when the ambient temperature rises by approximately 10°C. However, if the ambient temperature falls by approximately 10°C, the pressure decreases by approximately 3% to 4%.

[0057] The tightness of pressure chamber 10 is ensured by several of the following elements. Referring to Fig. 2. Firstly, the first static sealing element 22a, which is arranged between a first adapter part 20 and a second adapter part 21, prevents the fluid 9 from escaping. Furthermore, a second static sealing element 22b is arranged between the first adapter part 20 and the second adapter part 21. The two static sealing elements 22a and 22b are preferably O-rings. In addition, the first adapter part 20 and the second adapter part 21 are arranged coaxially with respect to the longitudinal axis A within the inner housing 7.

[0058] Referring to Fig. Furthermore, the second adapter part 21 has a tubular section 21b in which the lifting element 5 is guided and displaceable. An inner wall 21i of the tubular section 21b of the second adapter part 21 and an outer surface 6 of the lifting element 5 have minimal clearance, so that the tubular section 21b acts as a guide element for the lifting element 5. The stator 4 is rigidly and rotationally secured between a hollow cylindrical bushing 27 and the tubular section 21b of the second adapter part 21. The bushing 27 is also arranged coaxially with respect to the longitudinal axis A in the inner housing 7, with the bushing 27 resting on a second inner base 7b of the inner housing 7.

[0059] Secondly, a movable cylindrical sealing element 16 with a first dynamic piston seal 17a, which sealing element 16 is movably arranged in the guide tube 14, prevents fluid 9 from escaping from the inner housing 7 to the outside. Furthermore, the sealing element 16 has a second dynamic piston seal 17b, wherein each piston seal 17a, 17b bears tightly against an inner surface 15 of the guide tube 14, forming a fluid seal.

[0060] The guide tube 14 is further arranged concentrically with respect to the inner housing 7. The guide tube 14 has a first end 14a and a second end 14b opposite the first end 14a. The first end 14a of the guide tube 14 is connected to an alignment element 26 via a plug connection in a region of an inner base 7a of the inner housing 7, while the second end 14b of the guide tube 14 is inserted into an annular recess 21a of the second adapter part 21. The second end 14b of the guide tube 14 is further clamped between the first adapter part 20 and the second adapter part 21. Fig. 2.

[0061] The cylindrical sealing part 16, which is displaceably arranged in the guide tube 14 and is firmly connected to the lifting element 5 at its first end 5a via a plug connection, is arranged coaxially with respect to the longitudinal axis A and concentrically with respect to an inner surface 15 of the guide tube 14 in the guide tube 14.

[0062] Referring to Fig. 2. The sealing part 16 further has a first side 16a and a second side 16b opposite the first side 16a, wherein the first side 16a of the sealing part 16 faces the pressure chamber 10. Thus, the first side 16a of the sealing part 16 is in contact with the pressurized fluid 9.

[0063] Furthermore, the sealing part 16 has a centering element 16c designed as a blind hole, which faces the end face of the lifting element 5 at its first end 5a. An end face section of the lifting element 5 is arranged within the centering element 16c of the sealing part 16. The centering element 16c is also arranged coaxially with respect to the longitudinal axis A. In addition, a PTFE disc 27 rests flat on a base of the centering element 16c, with the side of the PTFE disc 27 facing away from the base being in contact with the end face of the lifting element 5.

[0064] Fig. Figure 4 shows an enlarged view of the guide tube 14 being coupled to the alignment element 26 at its first end 14a via a plug connection. The alignment element 26 is positioned coaxially with respect to the longitudinal axis A on the inner base 7a of the inner housing 7 within the pressure chamber 10. Thus, the alignment element 26 is clamped between the base 7a of the inner housing 7 and the first end 14a of the guide tube. Consequently, the guide tube 14 has two bearing sections.

[0065] Firstly, the first end 14a of the guide tube 14 is mounted in the alignment element 26, and secondly, the second end 14b of the guide tube 14, opposite the first end 14a, is mounted in the second adapter part 21, the guide tube 14 being rigidly and rotationally secured within the inner housing 7. In the initial position according to Fig. 3 the lifting element 5 is predominantly arranged inside the guide tube 14.

[0066] The invention works as follows: To move a pivoting flap VF of a vehicle, e.g. a tailgate, from a retracted starting position by means of the drive device 1 according to Fig. To open the 3, the electromagnetic linear motor 3 is supplied with a regulated current and voltage supply. A first magnetic field is generated via the stator 4, which interacts with a second magnetic field emanating from the permanent magnet 12 of the lifting element 5. This creates a repulsive force, as like magnetic poles NN and SS repel each other. In this way, the lifting element 5 is moved by means of like magnetic poles NN and SS according to Fig. 2 is displaced in an outward direction. Immediately after an initial displacement of the lifting element 5, the gas spring 8 applies supportive pressure to the sealing part 16 of the lifting element 5, so that the flap VF can be opened reliably, quietly, and with a defined acceleration and speed by means of the gas spring 8 in combination with the electromagnetic linear motor 3. The high-pressure fluid 9, which is located in the pressure chamber 10, assists the opening movement of the vehicle flap VF analogously to a compressed helical compression spring.

[0067] With the vehicle hatch VF fully open, the drive device 1 is in an extended position according to Fig. 1, wherein the fluid 9 is in an expanded state with a lower pressure compared to the compressed state in the pressure chamber 10.

[0068] To close the open flap VF and thus move the drive device 1 from the extended position according to Fig. 1 into the retracted starting position according to Fig. To return 3, the stator 4 is reversed and energized via a regulated current and voltage supply. This generates an attractive force because the opposite magnetic poles NS and SN attract each other. In this way, the lifting element 5 is driven by means of the opposite magnetic poles NS and SN according to Fig. 3 is displaced inwards in the outer housing 2. Furthermore, the weight of the vehicle flap VF supports compression of the fluid 9 within the pressure chamber 10.

[0069] Furthermore, the electromagnetic linear motor 3 can also act as a brake, particularly by decelerating the opening movement of the flap VF in a range of complete opening of the flap VF.

[0070] The invention has been explained above with reference to an exemplary embodiment in which the first connecting element 23 is associated with the outer housing 2, and in which the second connecting element 24 is associated with the lifting element 5. It is understood that, alternatively, the first connecting element 23 can be connected to the vehicle flap VF, and that the second connecting element 24 can alternatively be connected to the vehicle frame VB.

[0071] The invention has been explained above using an exemplary embodiment in which the drive device serves to open and close a vehicle hatch. It is understood that the drive device can also be used to open and close pivoting front doors, front door leaves, windows, skylights, roof hatches, garage doors, floor hatches, lift beds, as well as pivoting doors of kitchen cabinets and safes. Furthermore, the drive device could be used as a height-adjustable positioning device for furniture such as tables, chairs, and beds, particularly for hospital or office furniture. It is also intended that the drive device can be used as a positioning device in an exoskeleton, particularly for providing support in ergonomically unfavorable body postures or when lifting or lowering heavy objects. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2004 008 411 A1

[0006] EP 3 306 798 A1

[0007]

Claims

[1] Drive device (1) for opening and closing a pivoting vehicle hatch (VF), comprising an outer casing (2) with a longitudinal axis (A), which outer casing (2) has a first end (2a) and a second end (2b) opposite the first end (2a), an electromagnetic linear motor (3) comprising a stator (4) and a rod-shaped lifting element (5) displaceable along the longitudinal axis (A) with a first end (5a) and with a second end (5b) opposite the first end (5a), wherein the lifting element (5) can be extended telescopically from the outer housing (2) and can be retracted telescopically into the outer housing (2), wherein the lifting element (5) and the stator (4) can be coupled to each other at least section by means of a magnetic coupling (13), wherein the outer housing (2) comprises an inner housing (7) with a gas spring (8), wherein the gas spring (8) has a pressurized pressure chamber (10) filled with a fluid (9), wherein the fluid (9) exerts a pressure force on the lifting element (5), characterized by , that the pressure chamber (10) and the electromagnetic linear motor (3) are fluid-tightly separated from each other. [2] Drive device according to claim 1, characterized by , that the stator (4) is designed as a tubular coil set, which coil set preferably comprises several coils. [3] Drive device according to claim 1, characterized by , that the stator (4) comprises a coil for generating a magnetic field with a plurality of turns, and that the lifting element (5) has an armature made of a magnetizable material which can be arranged in the magnetic field and which armature can be deflected by the magnetic field of the coil. [4] Drive device according to any one of claims 1 to 3, characterized by, that the stator (4) has an inner circumference (4c), which inner circumference (4c) defines an opening (11). [5] Drive device according to claim 4, characterized by , that the lifting element (5) is arranged at least sectionally in the opening (11) of the stator (4), and that the lifting element (5) is displaceable relative to the stator (4) along the longitudinal axis (A). [6] Drive device according to any one of claims 1 to 5, characterized by , that the lifting element (5) has a plurality of magnets (12). [7] Drive device according to claim 6, characterized by , that the magnets (12) are arranged in a row adjacent to each other along a longitudinal extension of the lifting element (5). [8] Drive device according to claim 7, characterized by , that the magnets (12) are enclosed by an outer surface (6) of the lifting element (5). [9] Drive device according to any one of claims 1 to 8, characterized by, that a rigid guide tube (14) is arranged in the inner housing (7), which guide tube has a first end (14a) and a second end (14b) opposite the first end (14a), and that the guide tube (14) is arranged coaxially with respect to the longitudinal axis (A). [10] Drive device according to claim 9, characterized by , that the lifting element (5) has a cylindrical sealing part (16) at its first end (5a), which sealing part (16) is arranged inside the guide tube (14), and which sealing part (16) is displaceable relative to the guide tube (14). [11] Drive device according to claim 9 or 10, characterized by , that the lifting element (5) can be arranged at least sectionally within the guide tube (14), and that the lifting element (5) can be displaced relative to the guide tube (14). [12] Drive device according to claim 10, characterized by, that the cylindrical sealing part (16) is designed as a dynamic piston sealing arrangement with at least one piston seal (17a, 17b) which piston seal (17a, 17b) is fluid-sealed against an inner surface (15) of the guide tube (14). [13] Drive device according to any one of claims 1 to 12, characterized by , that the lifting element (5) is arranged coaxially with respect to the longitudinal axis (A), and that the stator (4) is arranged coaxially with respect to the longitudinal axis (A). [14] Drive device according to any one of claims 1 to 13, characterized by , that the outer casing (2) and the inner casing (7) form an annular gap (18) which annular gap (18) is fluid-tightly separated from the pressure chamber (10). [15] Drive device according to claim 14, characterized by , that an electrical cable (19) is arranged within the annular gap (18). [16] Drive device according to any one of claims 1 to 15, characterized by, that in the inner housing (7) a first adapter part (20) and a corresponding second adapter part (21) are arranged, that the first adapter part (20) and the second adapter part (21) rest complementarily on each other at their end faces, and that at least one static sealing element (22a, 22b) is arranged between the first adapter part (20) and the second adapter part (21). [17] Drive device according to claim 16, characterized by , that the first adapter part (20) and the second adapter part (21) are connected to each other via a plug connection in a rotationally secured manner. [18] Drive device according to any one of claims 1 to 17, characterized by , that the outer housing (2) has a first connection element (23) at its first end (2a), and that the outer housing (2) has a through-opening (25) for the movable lifting element (5) at its second end (2b). [19] Drive device according to claim 18, characterized by, that the first connecting element (23) is materially connected to the outer housing (2). [20] Drive device according to any one of claims 1 to 19, characterized by , that the lifting element (5) has a second connecting element (24) at its second end (5b). [21] Drive device according to any one of claims 1 to 20, characterized by , that the current for the stator (4) can be controlled via a control system. [22] Drive device according to any one of claims 1 to 21, characterized by , that a defined position of the lifting element (5) can be detected by means of sensors. [23] Drive device according to any one of claims 1 to 22, characterized by , that the stator (4) is arranged sealed inside the inner housing (7) in a region of the second end (2b) of the outer housing (2). [24] Drive device according to any one of claims 1 to 23, characterized by, that the lifting element (5) is designed as a hollow body with an inner surface, and that the inner surface of the lifting element (5) is free of fluid (9). [25] Drive device according to any one of claims 1 to 24, characterized by , that the lifting element (5) is made of a plastic. [26] Drive device according to any one of claims 1 to 25, characterized by , that the inner casing (7) is made of an aluminium alloy or of steel.

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