Door drive

Abstract

The invention relates to a door drive (200) for a door, comprising a housing (210) with a hydraulic cylinder (212), a drive mechanism (218) which can be coupled to the door and is arranged in the hydraulic cylinder (212) with a movable drive piston (220) and a closing spring (224) which acts on the drive piston (220) in the closing direction of the door, wherein a pressure chamber (214) for acting on the drive piston (220) with a hydraulic fluid (102) in the opening direction of the door is formed on the side of the drive piston (220) opposite the closing spring (224), a hydraulic system (90), and a hydraulic pump (10) for pumping the hydraulic fluid (102) into the pressure chamber (214).

Description

[0001] The present invention relates to a door drive for a door, comprising a housing with a hydraulic cylinder, a drive mechanism which can be coupled to the door and is arranged in the hydraulic cylinder and has a displaceable drive piston and a closing spring which acts on the drive piston in the closing direction of the door, wherein a pressure chamber for acting on the drive piston with a hydraulic fluid in the opening direction of the door is formed on the side of the drive piston opposite the closing spring, a hydraulic system, and a hydraulic pump for conveying the hydraulic fluid into the pressure chamber, according to the preamble of claim 1 and claim 2.

[0002] A door drive of the type mentioned above is known from WO 2006 / 066666 A1.

[0003] Mechanical door closers, especially those with hydraulic damping, are generally well-known and used worldwide. These door closers typically utilize a closing spring as a mechanical energy storage device. This spring is pre-tensioned when the door is opened and ensures secure closing once the door is released. However, such mechanical door closers can pose a problem for certain groups of people, such as disabled people, the elderly, or young people, as well as for autonomous vehicles, because, as described above, additional force is required to pre-tension the closing spring.

[0004] Fully automatic door drives can solve this problem, but they are complex to purchase, install, operate, and maintain, making them costly. Automatic door drives with hydraulic drive systems are also available. However, it has been found that hydraulic pumps for use in door drives must meet stringent requirements, such as the required pressure, the lowest possible leakage rate, a small installation space requirement, and low operating noise. Conventional hydraulic pumps, such as gear pumps or vibration pumps, cannot fully meet these numerous requirements.

[0005] The document WO 2006 / 066666 A1 mentioned at the outset discloses a door drive with a drive unit which can be coupled to the door via an output shaft and is arranged in a housing, with a motor which is drivingly connected to the drive unit and with a spring energy accumulator arranged in the housing and coupled to the motor and the drive unit, wherein a hydraulic pump in the form of a proportional piston pump is provided which is drivingly connected to the motor and which is hydraulically connected to a first pressure chamber assigned to the drive unit and a separate second pressure chamber assigned to the spring energy accumulator, wherein a hydraulic damping device is provided which is arranged between a receiving chamber for the drive unit and an intermediate chamber of the housing which is adjacent to the second pressure chamber.

[0006] Further hydraulic door drives are known from DE 103 29 562 B4, EP 1 431 496 A2 and DE 40 02 747 C3.

[0007] The object of the present invention is to at least partially remedy the above-described disadvantages of known door drives of the prior art. In particular, the object of the present invention is to provide a door drive with a hydraulic drive that has a low, preferably no, leakage rate and a compact and inexpensive design. Furthermore, it can provide sufficiently high pump pressures for door drives during operation with the lowest possible operating noise.

[0008] The above object is achieved by the patent claims. In particular, the object is achieved by a door drive having the features of independent claim 1 and by a door drive having the features of independent claim 2. Further features and advantages of the door drive according to the invention emerge from the subclaims, the description, and the drawings.

[0009] According to the invention, the object is achieved by a door drive for a door, comprising a housing with a hydraulic cylinder, a drive mechanism which can be coupled to the door and is arranged in the hydraulic cylinder and has a displaceable drive piston and a closing spring which acts on the drive piston in the closing direction of the door, wherein on the side of the drive piston opposite the closing spring, a pressure chamber is formed for pressurising the drive piston with a hydraulic fluid in the opening direction of the door, a hydraulic system, and a hydraulic pump for conveying the hydraulic fluid into the pressure chamber. The door drive according to the invention is characterized in that the hydraulic pump is designed as a piston pump with a fluid chamber which is axially displaceable and non-rotatably arranged and against a wall of the

[0010] Fluid chamber sealed pump piston which delimits a pump chamber connected to the pressure side of the hydraulic pump, wherein the hydraulic system has a first hydraulic connection which connects the pump chamber to the pressure chamber, wherein the hydraulic pump comprises an electric motor unit with a drive shaft and a drive section of the drive shaft is coupled to the pump piston via a threaded connection in order to axially displace the pump piston in the fluid chamber and thereby execute a stroke of the piston.

[0011] The door drive according to the invention is intended for use on a door, in particular to open it hydraulically on the one hand and to close it automatically, in particular independently mechanically, after an opening process. The door drive according to the invention can be installed both on the hinge side and opposite the hinge, as well as in door leaf or head mounting. During a door opening process, regardless of whether it is a manual opening process or a hydraulically driven opening process, the drive piston inside the hydraulic cylinder of the housing of the door drive according to the invention is displaced against the force of the closer spring, whereby mechanical energy is stored as potential energy in the closer spring. After the drive piston is released, this mechanical energy stored in the closer spring is released and the drive piston is moved back to its original position.The result is that the door equipped with the door drive according to the invention closes.

[0012] In particular, the door drive according to the invention is provided as a hydraulically driven door drive. For this purpose, the door drive according to the invention has, in particular, a hydraulic pump for conveying the hydraulic fluid, which can convey hydraulic fluid into a pressure chamber via a first hydraulic connection of the hydraulic system of the door drive according to the invention. This pressure chamber is arranged on the side of the drive piston opposite the closing spring, so that the application of hydraulic fluid to the pressure chamber leads to a displacement of the drive piston against the force of the closing spring and thus, mediated by the drive mechanism, which drives, for example, a drive shaft and a lever linkage or a lever-slide rail unit coupled thereto for driving purposes, to an opening process of the door.

[0013] According to the invention, the hydraulic pump of the door drive according to the invention is designed as a piston pump, in particular as a single-piston pump. The pump piston of the piston pump moves in a fluid chamber in which the pump piston is arranged axially displaceably and simultaneously in a rotationally fixed manner. Due to the rotationally fixed arrangement, the pump piston is automatically guided in the fluid chamber. By sealing against a wall of the fluid chamber, a pump chamber is defined in the fluid chamber and, secondly, this sealing can enable a low or even negligible leakage rate.The pump chamber, defined by the pump piston in the fluid chamber, is connected to the pressure side of the hydraulic pump. When the pump piston moves in the fluid chamber, reducing the volume of the pump chamber, the hydraulic fluid is pumped from the pump chamber into the pressure chamber upstream of the drive piston via the first hydraulic connection, which connects the pressure side of the hydraulic pump to the pressure chamber. This makes it particularly easy to supply the drive piston with hydraulic fluid, which simultaneously allows the drive piston to be displaced by applying the hydraulic fluid against the force of the closing spring.

[0014] In particular, the door drive according to the invention provides that the hydraulic pump has an electric motor unit as the drive, the drive shaft of which is coupled to the pump piston via a threaded connection. Such a threaded connection allows particularly high pressures to be generated, since the threaded connection can provide a high transmission ratio between the rotational speed of the drive shaft and the displacement speed of the pump piston in the fluid chamber.

[0015] At the same time, a threaded connection is a particularly simple mechanical drive connection, as it eliminates the need for complex and maintenance-intensive wobble or swash plates, connecting rods, and / or lever linkages for moving the pump piston. The installation space requirements of such a drive with a threaded connection are also reduced compared to similar piston pumps. Furthermore, by eliminating the aforementioned complex mechanical components, operating noise during operation of the door drive according to the invention can be reduced.

[0016] In summary, by using a hydraulic pump designed as a piston pump with a pump piston moved via a threaded connection, particularly high pumping pressures can be achieved while simultaneously reducing operating noise compared to other hydraulic pumping concepts. The power requirement of the piston pump according to the invention is also reduced compared to other hydraulic pumping concepts. Furthermore, the design of the hydraulic pump of the door drive according to the invention is particularly compact, mechanically simple, and therefore less maintenance-intensive, and enables particularly low leakage rates, thus saving maintenance costs.

[0017] Furthermore, in the door drive according to the invention, it can be provided that an axis of the threaded connection is offset from a central axis of the pump piston in order to arrange the pump piston in a rotationally fixed manner in the pressure chamber. By offsetting the axis of the threaded connection and a central axis of the pump piston, the pump piston can be supported on the wall of the fluid chamber, thereby preventing the pump piston from rotating when the drive shaft rotates. A rotationally fixed arrangement of the pump piston in the fluid chamber can thus be made particularly easy. In particular, in this embodiment of the door drive according to the invention, the pump piston and the fluid chamber can be cylindrical. This can simplify the manufacture of these elements of the door drive according to the invention.

[0018] Alternatively or additionally, the door drive according to the invention can be characterized in that, for the rotationally fixed arrangement of the pump piston in the fluid chamber, the pump piston is received in the fluid chamber in a form-fitting manner in the circumferential direction, in particular wherein the pump piston and the wall of the fluid chamber have a shape other than a circle and / or wherein a guide groove is provided on the pump piston and a corresponding guide pin is provided on the wall of the fluid chamber, or vice versa. In this embodiment, instead of or in addition to an axial offset of the threaded connection and the pump piston, a rotationally fixed arrangement of the pump piston is achieved by a form-fitting connection between the pump piston and the fluid chamber in the circumferential direction; rotation of the pump piston in the circumferential direction is prevented by the form-fitting contact of the pump piston with the fluid chamber.This can be achieved, for example, by a shape other than a circle for the pump piston and the wall of the fluid chamber. This shape can be, for example, elliptical, polygonal, or even essentially circular with a linear section. A guide groove and a corresponding engaging guide pin, with one of these elements arranged on the wall of the fluid chamber and the other on the pump piston, also lead to a support of the pump piston on the wall of the fluid chamber and, as a result, to a rotationally fixed arrangement of the pump piston in the fluid chamber.

[0019] The door drive according to the invention can also be designed such that the threaded connection is formed as a trapezoidal thread, a buttress thread, a ball thread, or a roller thread. The thread types listed above can transmit particularly high forces. This allows the drive piston to be displaced against closing springs with particularly high spring stiffness. This allows, in particular, the closing spring installed in the door drive according to the invention to be shortened overall, thereby reducing the installation space requirements for the door drive according to the invention.

[0020] Furthermore, in the door drive according to the invention, it can be provided that for the threaded connection, the drive section is designed as a threaded spindle with an external thread and the pump piston has a receiving area, preferably a receiving bore, for receiving the threaded spindle, wherein the receiving area is designed at least in sections as a threaded nut with a corresponding internal thread, wherein the threaded nut is preferably arranged at an end of the pump piston facing the motor unit. In this first possible implementation of the threaded connection, the drive shaft has an external thread and the pump piston has a corresponding internal thread. The receiving area of ​​the pump piston is preferably dimensioned such that at an end position of the pump piston in the fluid space close to the motor unit, the entire drive section designed as a threaded spindle is received in the receiving area of ​​the pump piston.At the same time, it is preferred that the drive section, designed as a threaded spindle, be of such a length that the threaded connection between the threaded spindle and the threaded nut on the pump piston is maintained even when the pump piston is arranged at its position in the fluid chamber at its maximum distance from the motor unit. This enables particularly reliable movement of the pump piston in the fluid chamber between the end positions described above.

[0021] Alternatively, the door drive according to the invention can be characterized in that the pump piston has a piston plate sealed against the axial wall of the fluid chamber and a spindle section arranged on the piston plate, wherein for the threaded connection the spindle section is designed as a threaded spindle with an external thread and the drive section has a cylindrical receiving area, preferably a receiving bore shaped as a blind hole, for receiving the spindle section, wherein the receiving area is designed at least in sections as a threaded nut with a corresponding internal thread, wherein the threaded nut is preferably arranged at an end of the receiving area facing away from the motor unit. In contrast to the embodiment of the door drive according to the invention described above, the elements of the threaded connection are interchanged in the alternative embodiment now described.Thus, the threaded spindle is designed as a spindle section of the pump piston, and the receiving area for receiving this threaded spindle is provided by the drive shaft. The advantageous size relationships between the receiving area and the threaded spindle listed for the previously described embodiment are also applicable in the present embodiment.

[0022] The door drive according to the invention can preferably be designed such that a sealing element, in particular comprising an O-ring and a piston sealing ring, is arranged circumferentially on the pump piston to seal against the axial wall of the fluid chamber. The use of an additional and specially provided sealing element can enable even better and more effective sealing of the space delimited by the pump piston. Leakage rates can thus be further reduced or, preferably, even completely prevented.

[0023] The door drive according to the invention can also be designed such that the drive piston can be displaced into an open position by a single stroke or multiple strokes, preferably a single stroke, of the pump piston against the force of the closing spring. The volume of the pump chamber determines the amount of hydraulic fluid that is pumped into the pressure chamber in front of the drive piston during one stroke of the pump piston. The smaller this volume of the pump chamber, the smaller the cross-section of the pump chamber transverse to the stroke and thus also the force required to displace the pump piston. On the other hand, however, correspondingly more strokes are then necessary to bring the pump piston fully into its open position.In other words, a smaller pump chamber volume allows for a more compact design of the door drive according to the invention, but requires a longer door opening process due to the higher number of pump strokes usually required, and vice versa. In particular, the appropriate design of the hydraulic pump can be selected depending on the location and / or purpose of the door drive according to the invention.

[0024] The door drive according to the invention can also be designed such that, in the assembled state of the door drive, the opening position of the drive piston corresponds to an opening angle of the door between greater than 0° and 180°, in particular between 75° and 105°, preferably 90°. An opening angle between greater than 0° and 180° makes it possible, in particular, to freely select the opening range of the door. A door opening angle of 75° to 105°, in particular 90°, can provide the door user with a sufficiently wide opening. The opening position of the drive piston can correspond to the maximum opening angle of the door, but also to a smaller opening angle.

[0025] According to a further development, the door drive according to the invention can further be provided with a freewheel coupled to the drive mechanism, wherein the freewheel decouples a movement of the door from a movement of the drive piston in order to enable a freewheel functionality in the assembled state of the door drive after the drive piston has reached the open position and for the duration of the drive piston being arranged in the open position. After the drive piston has moved into its open position and the closing spring has been pretensioned as a result, the freewheel activates the freewheel functionality of the door drive according to the invention. As a result, a movement of the door is decoupled from a movement of the drive piston. For this purpose, the freewheel can be arranged, for example, between a drive shaft of the door drive and a linkage of the door drive.The freewheel enables at least essentially resistance-free movement of the door or door leaf, in particular without the force of the closer spring. Overall, the door drive according to the invention can thus be used as a semi-automated or self-tensioning freewheel closer.

[0026] The door drive according to the invention can also be designed such that the pump piston is arranged in the fluid chamber between the pump chamber and the motor unit, whereby a pushing movement of the pump piston leads to the drive piston being pressurized with hydraulic fluid in the opening direction in the pressure chamber. In other words, in this embodiment of the door drive according to the invention, the pump piston moves away from the motor unit to pressurize the drive piston with hydraulic fluid.

[0027] Alternatively, the door drive according to the invention can be designed such that the pump chamber is formed in the fluid space between the pump piston and the motor unit, whereby a pulling movement of the pump piston leads to the drive piston being pressurized with the hydraulic fluid in the opening direction in the pressure chamber. In contrast to the previously described embodiment of the door drive according to the invention, in this embodiment the pump piston moves in the direction of the motor unit when the drive piston is pressurized with the hydraulic fluid. In special embodiments of the door drive according to the invention, such a pulling pumping movement can enable a simpler and / or more compact design of the hydraulic pump. However, the pulling pumping movement means that a seal between the pump chamber and the motor unit, particularly in the area of ​​a bearing of the drive shaft, must be able to withstand greater loads.

[0028] As stated above, the hydraulic pump of the door drive according to the invention can be designed as a push or pull type. Depending on the intended use and / or location of the door drive according to the invention, the most suitable hydraulic pump variant can be selected.

[0029] Furthermore, in the door drive according to the invention, it can be provided that the pump chamber is connected not only to the pressure side but also to the suction side of the hydraulic pump. Preferably, the pressure side and the suction side each have a check valve. Upon a pumping movement of the pump piston, the check valve on the pressure side opens and the check valve on the suction side closes, and upon a suction movement of the pump piston, the check valve on the pressure side closes and the check valve on the suction side opens. In particular, this configuration can be used for both pushing and pulling pumping operations.

[0030] For example, in the simplest embodiment of the door drive according to the invention, the pump chamber can be connected to the pressure chamber only via the first hydraulic connection and without check valves. A pumping movement of the pump piston conveys the hydraulic fluid from the pump chamber, which forms the pressure side of the hydraulic pump, into the pressure chamber. A suction movement of the pump piston, on the other hand, then sucks the hydraulic fluid out of the pressure chamber via the first hydraulic connection, whereby the pump chamber forms the suction side of the hydraulic pump.

[0031] Preferably, however, separate lines or hydraulic connections can be provided between the pump chamber and the pressure chamber, whereby the flow directions in the hydraulic connections can then be specified accordingly via check valves.

[0032] In particular, the hydraulic connection connected to the suction side of the hydraulic pump can also be connected to a correspondingly provided fluid reservoir in order to enable multiple pumping strokes to be carried out without having to empty the pressure chamber again each time hydraulic fluid flows into the pump chamber on the suction side. Again, this is possible for both pushing and pulling pumping operations. In particular, it can even be provided that a pump chamber is provided in the hydraulic pump on both sides of the pump piston, with both pump chambers being connected to both the pressure side and the suction side of the hydraulic pump, and the hydraulic connections used having correspondingly switched check valves.This ensures that, regardless of the direction of movement of the pump piston, one of the pump chambers always delivers hydraulic fluid to the pressure chamber, while the other pump chamber draws hydraulic fluid from the fluid reservoir. Overall, this allows for continuous hydraulic fluid delivery.

[0033] According to a further preferred embodiment of the door drive according to the invention, it can further be provided that the pump piston, on its side opposite the pump chamber, delimits a holding chamber in the fluid chamber that is connected to the suction side of the hydraulic pump, wherein a connecting line with a check valve is arranged in the pump piston for a flow of hydraulic fluid from the holding chamber into the pump chamber when the pump piston moves in the direction of the holding chamber. In other words, in this embodiment, when the hydraulic fluid is pumped from the pump chamber into the pressure chamber, the holding chamber is simultaneously enlarged, whereby hydraulic fluid flows into this holding chamber. For the next stroke of the piston, it must be moved back to its starting position, wherein the connecting line with the correspondingly switched check valve in the pump piston enables a flow of hydraulic fluid from the holding chamber into the pressure chamber.After the pump piston is reset, the pump chamber is filled with hydraulic fluid again, which can be pumped towards the pressure chamber during the next stroke of the pump piston.

[0034] In a special embodiment of the door drive according to the invention, this can be characterized in that the connecting line ends in the receiving area and has a bypass line for the hydraulic fluid to flow past the threaded connection into the receiving area of ​​the pump piston and / or the external thread and / or the internal thread of the threaded connection have a recessed tooth root area and / or a shortened tooth tip area. In this embodiment, the pump piston of the hydraulic pump is designed with a receiving area into which the drive section of the drive shaft, designed as a threaded spindle, can be inserted. In order to enable the hydraulic fluid to flow from the supply chamber into the pressure chamber, it is therefore usually necessary for the hydraulic fluid to first flow from the supply chamber into the receiving area and from there further into the pressure chamber.This can be achieved, for example, through a bypass line, which in particular encompasses the area of ​​a threaded nut of the receiving area, or through the threaded connection, whose internal and / or external threads are preferably designed accordingly. The latter has the additional advantage that friction losses can be reduced by the hydraulic fluid in the threaded connection.

[0035] In an alternative specific embodiment of the door drive according to the invention, it can be configured such that the connecting line is arranged in the piston plate. This specific embodiment of the door drive according to the invention relates to a hydraulic pump whose pump piston is designed as a piston plate with a spindle section arranged thereon. A flow of hydraulic fluid into the receiving area, which in this embodiment is formed by the drive shaft, is not required. By arranging the connecting line only in the piston plate, a flow of hydraulic fluid from the holding chamber into the pump chamber can still be enabled.

[0036] Preferably, the door drive according to the invention can further be characterized in that a check valve is arranged in the first hydraulic connection to prevent a flow of hydraulic fluid from the pressure chamber to the pump chamber. Such a check valve can thus reliably prevent a simultaneous flow of hydraulic fluid from the pressure chamber to the pump chamber, particularly when the pump piston is reset in the fluid chamber, during which hydraulic fluid flows from the reserve chamber into the pump chamber. The actuation of the drive piston with the hydraulic fluid present in the pressure chamber, and thus in particular the preload of the closing spring, can be reliably maintained in this way.

[0037] In the door drive according to the invention, it is further provided that the hydraulic system has a second hydraulic connection which connects the pressure chamber, in particular via a drive piston interior, to a spring chamber in which the closing spring is arranged, wherein the second hydraulic connection has an electrically switchable shut-off valve for selectively releasing or preventing a flow from the pressure chamber into the spring chamber and thereby for moving the drive piston in the closing direction. In this embodiment, the spring chamber is also filled with hydraulic fluid. After the drive piston is pressurized with hydraulic fluid, it is axially displaced, which simultaneously reduces the spring chamber. For the drive piston to move back, it is therefore necessary that, on the one hand, hydraulic fluid flows out of the pressure chamber and, on the other hand, corresponding hydraulic fluid is refilled into the spring chamber.This can be achieved particularly easily via the second hydraulic connection. The electrically switchable shut-off valve enables external control or triggering of this movement of the drive piston in the closing direction. By locking the electrically switchable shut-off valve, the drive piston remains in its deflected position, keeping the closing spring preloaded.

[0038] Furthermore, the door drive according to the invention can be provided with at least one throttle valve arranged in the second hydraulic connection for hydraulically damping the movement of the drive piston in the closing direction. A throttle valve in a hydraulic connection determines the amount of hydraulic fluid that can flow through the hydraulic connection. Thus, the throttle valve, which is preferably adjustable, in the second hydraulic connection can determine how quickly hydraulic fluid can flow from the pressure chamber into the spring chamber, which also allows the closing speed of the door to be automatically adjusted.

[0039] Furthermore, the door drive according to the invention can be characterized in that the electrically switchable shut-off valve is open in a de-energized state and allows hydraulic fluid to flow from the pressure chamber into the second hydraulic connection. In other words, if the electrically switchable shut-off valve is not activated, the drive piston moves in the closing direction, driven by the closing spring. A door equipped with the door drive according to the invention is thus closed or held in a closed position when the electrically switchable shut-off valve is de-energized, in particular even in the event of a complete power failure. This makes it possible to use the door drive according to the invention, for example, on a fire door that must be securely closed in the event of a fire.

[0040] Alternatively, the door drive according to the invention can be characterized in that the electrically switchable shut-off valve is blocked in a de-energized state and prevents hydraulic fluid from flowing from the pressure chamber into the second hydraulic connection. In this alternative embodiment of the door drive according to the invention, which is particularly contrary to the variant described above, the electrically switchable shut-off valve is designed such that it is closed when it is not actively energized. In other words, once a door has been opened, it remains in this open state even in the event of a power failure, since hydraulic fluid is prevented from flowing from the pressure chamber into the spring chamber.In a further preferred development, it can even be provided that the door drive according to the invention is activated upon the occurrence of a triggering situation, for example a fire or a power failure, in such a way that the corresponding door is opened and subsequently held in the open position. For this purpose, the door drive according to the invention can, for example, have an additional electrical energy storage device in order to supply the hydraulic pump with electrical energy for opening the door once by pressurizing the pressure chamber with hydraulic fluid. The shut-off valve, which blocks when de-energized, then ensures that the door is held securely open. The use of a door drive according to the invention as part of a smoke and heat extraction system (RWA) can be enabled in this way.

[0041] The door drive according to the invention according to claim 1 is further characterized in that the fluid chamber and the spring chamber are separated by a plate element, in particular a spring plate supporting the closing spring, wherein the plate element has a sleeve, preferably deep-drawn, which is closed with respect to the spring chamber and extends into the spring chamber and encloses a sleeve chamber, wherein the sleeve chamber borders the fluid chamber without walls and thereby the fluid chamber is enlarged by the sleeve chamber, wherein the seal of the pump piston against the wall of the fluid chamber is arranged at an end of the pump piston facing the motor unit and, during operation of the hydraulic pump, a section of the pump piston extends at least temporarily into the sleeve chamber. In other words, in this embodiment, the fluid chamber is arranged at least partially inside the spring chamber.This can preferably be facilitated, for example, by designing the closing spring as a compression spring, in particular as a helical spring. Since this automatically also allows the pump piston to extend at least temporarily and in sections into the interior of the spring chamber during operation of the hydraulic pump, the entire door drive according to the invention can be designed to be more space-saving. To maximize this extension of the pump piston into the spring chamber, the seal and the threaded nut can both be arranged at the end of the pump piston facing the motor unit.

[0042] Alternatively, the door drive according to claim 2 is designed such that the fluid chamber and the spring chamber adjoin one another without any walls, wherein the seal of the pump piston against the wall of the fluid chamber is arranged at an end of the pump piston facing the motor unit, and during operation of the hydraulic pump, a section of the pump piston extends at least partially into the spring chamber. In this embodiment, the spring chamber thus at least substantially forms the suction side of the hydraulic pump. In this embodiment, too, the pump piston extends at least temporarily and in sections into the spring chamber. This embodiment, too, thus enables a more compact and space-saving design of the door drive according to the invention. In order to maximize the extension of the pump piston into the spring chamber, in this embodiment, too, the seal and the threaded nut can both be arranged at the end of the pump piston facing the motor unit.In contrast to the variant described above, in which both pushing and pulling operation of the hydraulic pump is possible, in this alternative variant only pulling operation is possible.

[0043] The door drive according to the invention can particularly preferably be characterized in that the hydraulic system has a third hydraulic connection which connects the spring chamber to the fluid chamber, in particular the pump chamber or the holding chamber, wherein the third hydraulic connection enables hydraulic fluid to flow from the spring chamber into the fluid chamber upon displacement of the drive piston in the opening direction of rotation. During a pumping movement of the pump piston, hydraulic fluid is conveyed from the pressure side of the hydraulic pump to the pressure chamber, whereby the drive piston is displaced against the force of the closing spring. As a result, the spring chamber is simultaneously reduced in size, wherein the hydraulic fluid displaced in this process flows via the third hydraulic connection back to the hydraulic pump, in particular to the suction side or to the holding chamber forming the suction side of the hydraulic pump.In this embodiment, the spring chamber thus forms at least part of the fluid reservoir described above. Overall, in this embodiment, the hydraulic system, together with the hydraulic pump, the pressure chamber, and the spring chamber, preferably represents a closed system. The corresponding volume changes that occur in the various chambers during operation of the door drive according to the invention correspond in pairs, in particular the volume changes of the pump chamber and the pressure chamber, the pressure chamber and the spring chamber, the spring chamber and the reserve chamber, and the reserve chamber and the pump chamber. Additional fluid chambers, in particular, for example, compensation tanks for accommodating hydraulic fluid, can thus be dispensed with in a door drive according to the invention.

[0044] The door drive according to the invention can also be characterized in that the first hydraulic connection and / or the second hydraulic connection and / or the third hydraulic connection is formed, at least in sections, as a bore, in particular a deep bore, in the housing of the door drive. In this way, the housing itself can be used to provide the hydraulic connections. Complex, particularly external, additional line elements for the hydraulic connection can be avoided.

[0045] Furthermore, in the door drive according to the invention, it can be provided that the fluid chamber is delimited on a side facing the electric motor unit by a bearing cover, wherein the bearing cover has a bearing in which the drive shaft is axially fixed and radially mounted, wherein the bearing cover preferably seals the fluid chamber against the environment. The bearing cover can thus fulfill three, preferably four, functions with a single component, namely delimiting the fluid chamber, supporting the drive shaft in the radial direction, fixing the drive shaft in the axial direction and preferably sealing the fluid chamber. Compared to a solution in which several components are required to fulfill these functions, installation space can thus be saved and the entire door drive according to the invention can be simpler and more compact.

[0046] Furthermore, the door drive according to the invention can be characterized in that the electric motor unit comprises a stepper motor and a planetary gear and / or a cycloidal gear, wherein the electric motor unit is preferably arranged outside the housing and fastened to the housing, in particular to a housing cover. Stepper motors are particularly precisely controllable electric motors, which enables particularly precise and simple adjustment of the hydraulic fluid pumped by the hydraulic pump of the door drive according to the invention. A planetary gear or a cycloidal gear, in turn, enables a particularly compact and space-saving transmission of a speed of the stepper motor into a speed of the drive shaft, with conversion of the motor torque into the required torque on the drive shaft.Another advantage of this type of geared stepper motor unit is the comparatively high torque provided for the required size and speed range. Locating the electric motor unit on the outside of the housing allows for particularly easy replacement and / or retrofitting of the entire electric motor unit.

[0047] In summary, a simple motor can be arranged as a motor unit outside the housing. However, it is preferred that the motor unit arranged outside the housing be designed as a geared motor, a stepper motor, or even a geared stepper motor. As explained above, the drive shaft of the motor can be designed, for example, as a threaded spindle. Alternatively, as also described above, a drive shaft with a threaded nut is conceivable, into which a threaded spindle of the pump piston engages.

[0048] The invention is described below with reference to the figures. Elements with the same function and mode of operation are provided with the same reference numerals in the figures.

[0049] They show schematically: Fig. 1 shows an external view of a door drive according to the invention, Fig. 2 shows a sectional view of a first embodiment of a door drive not according to the invention, Fig. 3 shows a sectional view of a first embodiment of a hydraulic pump of the door drive not according to the invention, Fig. 4 shows a sectional view of a second embodiment of a hydraulic pump of the door drive not according to the invention, Fig. 5 shows a sectional view of a third embodiment of a hydraulic pump of the door drive not according to the invention, Fig. 6 shows a detailed view of the Fig. 5 shown hydraulic pump, Fig. 7 a sectional view of a fourth embodiment of a hydraulic pump of a door drive not according to the invention, Fig. 8 a sectional view of a fifth embodiment of a hydraulic pump of the door drive according to the invention, Fig. 9 two sectional views of a sixth embodiment of a hydraulic pump of the door drive according to the invention, Fig. 10 a sectional view of a second embodiment of the door drive according to the invention, Fig. 11 a sectional view of a third, simplified embodiment of the door drive according to the invention in a first operating state, Fig. 12 the door drive according to the invention of Fig. 11 in a second operating state, Fig. 13 the door drive according to the invention of Fig. 11 in a third operating state, and Fig. 14 the door drive according to the invention of Fig. 11 in a fourth operating state.

[0050] Fig. 1 shows an external view of a door drive 200 according to the invention. Visible here is, in particular, a cover 202 of the door drive 200, which covers the housing 210 (cf. Fig. 2 ) of the door drive 200 according to the invention. As shown by way of example, a drive shaft 228 protrudes from the top of the hood 202, which drive shaft 228 is connected to a drive mechanism 218 arranged in the housing 210 (cf. Fig. 2 ) is drivingly connected. Furthermore, a linkage 230 is shown, which is designed in particular as a lever and ensures a drivingly effective coupling between a door leaf and a lintel of the corresponding door by means of the door drive 200 according to the invention mounted thereon. In particular, as shown, the door drive 200 according to the invention can have a freewheel 226, which is arranged, for example, between the drive shaft 228 and the linkage 230. Such a freewheel 226 can enable a separation of a movement of the drive shaft 228, and thus of the components of the drive mechanism 218 installed inside the housing 210, from a movement of the door leaf of the door. In the embodiment shown, all elements of the door drive 200 according to the invention that are necessary for the actual drive, in particular for the hydraulic drive, are arranged inside the housing 210.This illustrates the advantage of the door drive 200 according to the invention of being particularly compact and requiring little installation space.

[0051] In Fig. 2 An embodiment of the door drive 200 according to the invention is shown in a sectional view. In particular, this is a particularly simple embodiment of the door drive 200 according to the invention. A hydraulic cylinder 212, in which the drive mechanism 218 is arranged, is provided inside the housing 210. In particular, an axially displaceable drive piston 220 and a closing spring 224 that applies a force to the drive piston 220 are arranged in the hydraulic cylinder 212. The section of the hydraulic cylinder 212 in which the closing spring 224 is arranged is also called the spring chamber 216. The drive shaft 228 is coupled to the drive piston 220 via a meshing engagement as an operative connection, so that an axial movement of the drive piston 220 in the hydraulic cylinder 212 causes a rotation of the drive shaft 228 and vice versa.

[0052] For moving the drive piston 220 in the hydraulic cylinder 212, a hydraulic drive is provided in the door drive 200 according to the invention. This hydraulic drive comprises, in particular, a hydraulic pump 10, which has an electric motor unit 30 as the drive. According to the invention, the hydraulic pump 10 is designed as a piston pump. A pump piston 50 is arranged in a fluid chamber 12 and is sealed against a wall 18 of the fluid chamber 12, as shown preferably via a circumferential sealing element 56, for example comprising an O-ring and a piston sealing ring. This enables particularly low leakage rates of the entire hydraulic pump 10. A translational pumping or suction movement of the pump piston 50 in the fluid chamber 12 is driven by a drive shaft 32 of the motor unit 30, which, as is essential to the invention, is drivingly connected to the pump piston 50 with its drive section 34 via a threaded connection 70.

[0053] The use of a threaded connection 70 offers several advantages. Thus, the threaded connection 70, which can be designed as a standard thread, but preferably also as a trapezoidal thread, a buttress thread, a ball thread, or a roller thread, can particularly easily and reliably convert the rotational movement of the drive shaft 32 into a translational movement of the pump piston 50, while simultaneously transmitting high forces. Thus, high pumping pressures can be generated by the hydraulic pump 10 of the door drive 200 according to the invention. By dispensing with a complex mechanism for displacing the pump piston 50 in the fluid chamber 12, comprising, for example, a connecting rod or linkage mechanism, a particularly compact design of the hydraulic pump 10 is also possible, which, in particular, also has low noise generation during operation.

[0054] As in Fig. 2 As shown, the motor unit 30 can also be arranged outside the housing 210 and fastened or flanged thereto. In this case, it can be provided, in particular, that the housing 210 and the motor unit 30 are covered by a common cover. The motor unit 30 preferably has an electric motor 36, for example a stepper motor, and a gear 38, for example a planetary gear and / or a cycloidal gear, whereby an accurate and precise control and / or regulation of a rotational speed of the drive shaft 32 can be achieved. The drive shaft 32 is preferably mounted by a bearing cover 40, which closes off the fluid chamber 12 at one end, wherein in particular the bearing 42 provided for this purpose effects both radial bearing and axial fixing of the drive shaft 32.

[0055] As already explained above, Fig. 2 a particularly simple embodiment of the door drive 200 according to the invention, particularly with regard to the installed hydraulics. The pump piston 50 defines a pump chamber 14 in the fluid chamber 12, which has a variable size upon axial displacement of the pump piston 50. Via a first hydraulic connection 92 of a hydraulic system 90 of the door drive 200 according to the invention, this pump chamber 14 is fluidly connected to a pressure chamber 214, wherein the pressure chamber 214 is located on the side of the drive piston 220 opposite the closing spring 224.

[0056] A movement of the pump piston 50, which leads to a reduction in the size of the pump chamber 14, thus conveys hydraulic fluid 102 from the pump chamber 14 into the pressure chamber 214. As a result, the drive piston 220 is displaced against the force of the closing spring 224, whereby at the same time, mediated via the drive mechanism 218, the drive shaft 228 and the rod 230 (not shown), the door opens and / or the closing spring 224 is pretensioned. In other words, with the above-described movement of the pump piston 50, the pump chamber 14 forms the pressure side 20 of the hydraulic pump 10. With a reverse movement of the pump piston 50, in Fig. 2 to the right in the direction of the motor unit 30, which leads to an enlargement of the pump chamber 14, hydraulic fluid 102 is sucked back from the pressure chamber 214 into the pump chamber 14 via the first hydraulic connection 92, whereby the pump chamber 14 is thus also connected to the suction side 22 of the hydraulic pump 10. The associated movement of the drive piston 220 in the closing direction is additionally supported by the preloaded closing spring 224.

[0057] The various embodiments of the door drive 200 according to the invention differ in particular in the design of the hydraulic pump 10 used, as well as in the different hydraulic systems 90 and the spaces connected thereby. Figuren 3 bis 9 Various possible embodiments of hydraulic pumps 10 of the door drive 200 according to the invention are described. All of these hydraulic pumps 10 share the inventive feature of a pump piston 50 driven by a threaded connection 70. The hydraulic pumps 10 shown in Figures 3 to 9 are described below, with particular attention being paid to the differences between the individual variants. To avoid repetition, components that are present in several of the variants are not described again for each variant.

[0058] Fig. 3 shows a detailed view of a possible hydraulic pump 10 of a door drive 200 according to the invention. Like all of these hydraulic pumps 10, this one also has a motor unit 30, which comprises an electric motor 36 and a gear 38 for driving a drive shaft 32. The drive shaft 32, in turn, is radially mounted and axially fixed by a bearing 42. The bearing 42 is arranged in a bearing cover 40, which in turn delimits a fluid chamber 12 of the hydraulic pump 10. The fluid chamber 12 is otherwise arranged in a housing 210 of the door drive 200. A pump piston 50 is axially displaceably mounted in the fluid chamber 12. In this embodiment, too, the pump piston 50 is sealed off from a wall 18 of the fluid chamber 12 by a circumferential sealing element 56 and delimits a pump chamber 14 in the fluid chamber 12. As already described in the Fig. 2 In the variant shown, this pump chamber 14 is connected to both the pressure side 20 and the suction side 22 of the hydraulic pump 10.

[0059] In contrast to Fig. 2 The embodiment of a hydraulic pump 10 shown in Fig. 3 In the embodiment shown, in addition to the first hydraulic line 92, which is connected to the pressure side 20 of the hydraulic pump 10, a further hydraulic connection is provided which is connected to the suction side 22 of the hydraulic pump 10. A check valve 98 is provided in each of the two hydraulic connections 92, so that during a pumping movement of the pump piston 50, hydraulic fluid 102 is only delivered via the pressure side 20 of the hydraulic pump 10 and, similarly, during a suction movement of the pump piston 50, hydraulic fluid 102 is only sucked or pushed into the pump chamber 40 via the suction side 22 of the hydraulic pump 50.

[0060] In Fig. 3 a pushing operation of the hydraulic pump 10 is shown. By a corresponding arrangement (not shown) of the first hydraulic line 92 to that part of the fluid chamber 12 which is located between the pump piston 50 and the motor unit 30, the Fig. 3 The features and advantages described above are also possible during pulling operation of the hydraulic pump 10. In particular, by means of a corresponding arrangement of hydraulic lines with corresponding check valves (also not shown), both volumes formed by the pump piston 50 in the fluid chamber 12 can be used as pump chambers 14, which, depending on the direction of movement of the pump piston 50, are alternately connected to the pressure side 20 or the suction side 22 of the hydraulic pump 10. This makes it possible, in particular, to achieve continuous delivery operation of the hydraulic pump 10.

[0061] In the following, the Fig. 3 The threaded connection 70 of the hydraulic pump 10, which is essential to the invention, is described in more detail. As shown, the drive shaft 32, in particular its drive section 34, can be designed as a threaded spindle 72 with an external thread 80. In turn, a receiving area 74 is provided in the pump piston 50, into which the drive section 34 of the drive shaft 32 can be inserted, preferably completely. This receiving area 74 is partially designed as a threaded nut 76 with an internal thread 78, wherein the external thread 80 of the threaded spindle 72 and the internal thread 78 of the threaded nut 76 correspond to one another, engage with one another, and thus form the threaded connection 70.

[0062] As shown, the threaded nut 76 can preferably be arranged at an end of the pump piston 50 facing the motor unit 30. Furthermore, in the illustrated embodiment of the hydraulic pump 10, an axis of the threaded connection 70 is arranged offset from a central axis of the pump piston 50. The positive connection thus formed makes it particularly easy to ensure a rotationally fixed arrangement of the pump piston 50 in the fluid chamber 12. At the same time, this makes it possible for the fluid chamber 12 and the pump piston 50, the latter at least in the region of the seal relative to the wall 18 of the fluid chamber 12, to be designed cylindrically with a circular cross-section, thereby simplifying the sealing of the pump piston 50 relative to the fluid chamber 12.

[0063] In Fig. 4 is a variation of the Fig. 3 shown hydraulic pump 10. For elements of the hydraulic pump 10 of the Fig. 4 Therefore, reference is made to the corresponding description of the hydraulic pump 10 from Fig. 3 In particular, the threaded connection 70 is designed identically in both variants of the hydraulic pump 10. In contrast to the Fig. 3 The hydraulic pump 10 shown in Fig. 4 As shown, the hydraulic pump 10 has, in addition to the pump chamber 14, a holding chamber 16. Both the pump chamber 14 and the holding chamber 16 are formed as parts of the fluid chamber 12 and are delimited by the pump piston 50 and separated from one another by the latter. Furthermore, the pump chamber 14 is connected to the pressure side 20 of the hydraulic pump 10 and, via a first hydraulic connection 92, in which a check valve 98 is arranged, is fluidly connected to the pressure chamber 214 (not shown) of the door drive 200 according to the invention. The holding chamber 16, in turn, which is located on the opposite side of the pump piston 50 with respect to the pump chamber 14, is fluidly connected to the suction side 22 of the hydraulic pump 10 and also to a hydraulic connection.This has the particular advantage that, since during a pumping movement of the pump piston 50, in which the pump chamber 14 is reduced, the reserve chamber 16 simultaneously increases, hydraulic fluid 102 is pumped from the pressure side 20 of the hydraulic pump 10 and, at the same time, new hydraulic fluid 102 flows into the reserve chamber 16 on the suction side 22 of the hydraulic pump 10. After completion of a stroke of the pump piston 50, the latter is arranged at a left end of the fluid chamber 12, whereby the volume of the pump chamber 14 is minimal and the volume of the reserve chamber 16 is maximal.

[0064] In order to be able to execute a further stroke, for example if a single stroke is not sufficient to fully open the door equipped with the door drive 200 according to the invention, the pump piston 50 must be reset, in other words partially, preferably completely, displaced to the right in the fluid chamber 12. To ensure that the hydraulic fluid 102 present in the holding chamber 16 can simultaneously flow into the pump chamber 14, a connecting line 60 is arranged in the pump piston 50. A check valve 98 in the connecting line ensures, in particular, that hydraulic fluid 102 flows through the connecting line 60 only during the reset movement of the pump piston 50 and that the connecting line 60 is blocked during a pumping movement of the pump piston 50.

[0065] Fig. 5 shows a slight modification of the one already shown in Fig. 4 hydraulic pump 10 shown, to the above description of which reference is made. In the Fig. 5 The variant of the hydraulic pump 10 shown in Fig. 4 In the variant shown, the pressure side 20 and the suction side 22 of the hydraulic pump 10 are swapped. Of all the other components, only the hydraulic valve 98 is arranged exactly reversed in the connecting line 60. In other words, Fig. 5 a design of the hydraulic pump 10 for a pulling operation, whereas Fig. 4 shows a variant of the hydraulic pump 10 which is designed for a pushing operation. However, as a result, all the functions already described with reference to Fig. 4 described functions of the hydraulic pump 10, in particular the resetting of the pump piston 50 after execution of a stroke, also by the variant of the hydraulic pump 10 of the Fig. 5 be made possible.

[0066] As described above, when the respective pump piston 50 is reset, the fluid flows into the Fig. 4 , 5shown hydraulic pumps 10 hydraulic fluid 102 from the holding chamber 16 into the pump chamber 14, in particular regardless of which side of the pump piston 50 with respect to the motor unit 30 the respective holding chamber 16 or pump chamber 14 is arranged. As in the Fig. 4 , 5 shown, a connecting line 60 with a check valve 98 is provided for this purpose, which in particular connects the receiving area 74 in the pump piston 50 with the pump chamber 14 ( Fig. 4 ) or the holding room 16 ( Fig. 5 ). In both variants, the hydraulic fluid 102 must first flow into the receiving area 74.

[0067] Possible solutions for this are for the Fig. 4 shown embodiment of the hydraulic pump 10 as a detailed view in Fig. 6 For example, the connecting line 60 can comprise a bypass line 62, which allows the hydraulic fluid 102 to flow past the threaded connection 70. Alternatively or additionally, the external thread 80 of the threaded spindle 72 and / or the internal thread 78 of the threaded nut 76 can also have a recessed tooth root region 82 and / or a shortened tooth tip region 84. In this way, too, a flow of hydraulic fluid 102 from the corresponding part of the fluid chamber, in Fig. 6 from the holding area 16 into the receiving area 74.

[0068] Solutions for the hydraulic pump 10 of the Fig. 5 is obtained based on the Fig. 6 shown embodiment by replacing the reserve chamber 16 with the pump chamber 14 and by reversing the flow direction of the hydraulic fluid 102.

[0069] A variant of the hydraulic pump 10 which is significantly different from the possible embodiments of the hydraulic pump 10 shown so far is shown in Fig. 7 shown. Here too, the hydraulic pump 10 has, in addition to the usual components such as motor 30 as parts of the fluid chamber 12, a pump chamber 14 and a holding chamber 16, which are separated from each other by the pump piston 50. However, the structure of the pump piston 50 and the drive section 34 of the drive shaft 32 differs from the Fig. 7 illustrated variant of the hydraulic pump 10 from the possible embodiments of hydraulic pumps 10 described above.

[0070] The pump piston 50 has, in particular, a piston plate 52, which carries the sealing element 56 for sealing against the wall 18 of the fluid chamber 12. Furthermore, the connecting line 60 and the corresponding check valve 98 are arranged in the piston plate 52. A spindle section 54 is provided on the piston plate 52, which is designed as a threaded spindle 72 and extends in the direction of the motor unit 30. To accommodate this spindle section 54, the drive shaft 32, in particular its drive section 34, has a receiving area 74 into which the spindle section 54 can be immersed, preferably completely, as shown. At the end of the receiving area 74 facing away from the motor unit 30, this is designed as a threaded nut 76, which has an internal thread 78 and thus engages with the external thread 80 of the threaded spindle 72. In order to enable an exchange of hydraulic fluid 102 between the holding chamber 16 and the receiving area 74, analogous to the Fig. 6 In the solutions shown, compensating bores 62 can be provided in the drive section 34 and / or in the threaded spindle 72 or corresponding configurations of the threaded connection 70. In this way, the threaded connection 70 essential to the invention for driving the axial displacement of the pump piston 50 in the fluid chamber 12 is also formed in this embodiment. Furthermore, as shown, an axial offset can also be provided in this embodiment for the rotationally fixed arrangement of the pump piston 50 in the fluid chamber 12 between the threaded connection 70 and the fluid chamber 12.

[0071] Another possible embodiment of the hydraulic pump 10 is shown in Fig. 8 In this embodiment of the door drive 200 according to the invention, in which the hydraulic pump 10 of the Fig. 8 is installed, the spring chamber 216 is also filled with hydraulic fluid 102. In particular, the fluid chamber 12 of the hydraulic pump 10 and the spring chamber 216 border one another without any walls. In other words, no separation is required between the spring chamber 216 and the fluid chamber 12. At the same time, the seal of the pump piston 50 against the wall 18 of the fluid chamber, in particular provided by the sealing element 56, is arranged at an end of the pump piston 50 facing the motor unit 30. As a result, the pump piston 50 can extend at least temporarily into the spring chamber 216 during an axial displacement driven by the motor unit 30. If, as shown, the closing spring 224 is designed as a compression spring, in particular as a helical spring, the pump piston 50 can preferably even extend into the interior of the closing spring 224, thereby enabling a particularly compact design of the door drive 200 according to the invention.In other words, the spring chamber 216 essentially forms the suction side 22 of the hydraulic pump 10. A separately provided reserve chamber 16 (in . Fig. 8 not shown) of the hydraulic pump 10 can thus be omitted. Overall, with this construction, only a pulling operation of the hydraulic pump 10 is possible. In summary, in this way, a particularly simple, compact and space-saving embodiment of the hydraulic pump 10 and, as a result, also of the door drive 200 according to the invention can be made possible. Otherwise, the hydraulic pump 10 is like the one already described with reference to Fig. 5 described variant of the hydraulic pump 10.

[0072] Fig. 9 shows a further variant of the hydraulic pump 10 in two sectional views, in which the pump piston 50 also extends at least partially into the spring chamber 216. Figure A shows a section through the entire door drive 200, and Figure B shows a perspective section through elements of the corresponding hydraulic pump 10.

[0073] In contrast to the Fig. 8 In the variant shown, the fluid chamber 12 is sealed off from the spring chamber 216. For this purpose, in particular, a plate element 110 is provided, which is arranged between the spring chamber 216 and the fluid chamber 12. In particular, the plate element can be a spring plate 112 supporting the closing spring 24. This plate element 110 has a sleeve 114, for example, which is deep-drawn and closed with respect to the spring chamber 216 and extends from the plate element 110 into the spring chamber 216. Due to the design of the closing spring 224 as a compression spring, in particular as a helical spring, the sleeve 114 can preferably also extend into the interior of the closing spring 224. The sleeve chamber 116 formed inside the sleeve 114 borders the fluid chamber 12 without walls, whereby the fluid chamber 12 is increased in size by the volume of the sleeve chamber 116. Overall, the pump piston 50 can therefore also extend into the part of the fluid chamber 12 formed by the sleeve chamber 116.The ones already mentioned in relation to . Fig. 8 The advantages described with regard to a particularly compact and space-saving embodiment of the hydraulic pump 10 and, as a result, also of the door drive 200 according to the invention can thus also be achieved by the Fig. 9 shown embodiment of the hydraulic pump 10.

[0074] As shown, for example, the sleeve chamber 116, as part of the fluid chamber 12, can form the reserve chamber 16 of the hydraulic pump 10. As already described above with regard to other embodiments of the hydraulic pump 10, a connecting line 60 with a check valve 98 is arranged in the pump piston 50, which allows hydraulic fluid 102 to flow from the reserve chamber 16 into the pump chamber 14 when the pump piston 50 is reset. Fig. 9 In other words, and in particular in contrast to the variant shown in Fig. 8 The embodiment shown also allows for pushing operation of the hydraulic pump 10, with at least substantially the same installation space requirements. However, by means of a corresponding configuration, in particular by interchanging the suction side 22 and pressure side 20 or the holding chamber 16 and the pump chamber 14, as well as by reversing the check valve 98 in the connecting line 60, pulling operation can also be realized.

[0075] Regardless of the differences described above, in the Fig. 9 In the variant of the hydraulic pump 10 shown, it is also provided that the fluid chamber 12 and the threaded connection 70 are arranged without mutual axial offset. In order to nevertheless achieve a rotationally fixed arrangement of the pump piston 50 in the fluid chamber 12, the pump piston 50 is received in the fluid chamber 12 in a form-fitting manner in the circumferential direction. To achieve this, the otherwise circular cross section of the pump piston 50, in particular the cross section of the section of the pump piston 50 guided through the receptacle in the plate element 110, and of the fluid chamber 12, in particular the corresponding cross section of the receptacle of the plate element 110, is partially linearly flattened, see in particular Figure B of the Fig. 9 In other words, the receptacle in the plate element 110 and the corresponding section of the pump piston 50 have a respective contour which is designed to fit one another in a form-fitting manner.

[0076] Fig. 10 shows a possible embodiment of the entire door drive 200 according to the invention in a sectional view. In addition to the hydraulic drive components, in particular comprising the hydraulic pump 10, the door drive 200 according to the invention has mechanical components, for example a closing spring 224, by means of which a mechanical, in particular independent, closing functionality of the door drive 200 can be enabled. The representation of the Fig. 10 is particularly directed to the hydraulic function of the door drive 200 according to the invention. Therefore, only the components of the door drive 200 according to the invention that are essential for this operation are described below. This applies to the embodiments of the Figuren 10 -14 , wherein the hydraulic pump according to the invention is designed in each case according to the Fig.8 or 9 is executed.

[0077] In this embodiment, the hydraulic pump 10 also has a pump piston 50 that is axially displaceable via a motor unit 30 and coupled to the motor unit 30 via a threaded connection 70. The hydraulic pump 10 has a pressure side 20 and a separate suction side 22, wherein a pump chamber 14 of the hydraulic pump 10 is connected to the pressure side 20 and a holding chamber 16, separated from the pump chamber 14 by the pump piston 50, is connected to the suction side 22 of the hydraulic pump 10.

[0078] Furthermore, the illustrated door drive 200 has a hydraulic system 90 with a plurality of hydraulic connections 92, 94, 96, 104. Preferably, at least parts of these hydraulic connections 92, 94, 96, 104 can be formed as deep holes in the housing 210 of the door drive 200 according to the invention. Thus, the pump chamber 14 of the hydraulic pump 10 is connected via a first hydraulic connection 92, in which a correspondingly arranged check valve 98 is placed, to the pressure chamber 214, which is arranged on the side of the drive piston 220 facing away from a closing spring 224. A second hydraulic connection 94 enables hydraulic fluid 102 to flow between the pressure chamber 114 and the spring chamber 216, wherein for this purpose, in particular, the hydraulic fluid 102 also flows through the drive piston interior 222. A third hydraulic connection 96 in turn enables hydraulic fluid 102 to flow from the spring chamber 216 to the reserve chamber 16 of the hydraulic pump 10.A fourth hydraulic connection 104 enables hydraulic fluid 102 to flow from the spring chamber 216 into the pressure chamber 214, in particular through a check valve 98 correspondingly arranged in the fourth hydraulic connection 104. In particular, an electrically switchable check valve 300 is arranged in the second hydraulic connection 94. This check valve 300 can be closed or open with appropriate electrical control. Both alternatives of the check valve 300 can be used in a door drive 200 according to the invention, namely that the check valve 300 is closed when energized, or that the check valve is open when energized. In the following, the door drive 200 according to the invention shown will initially be described in general terms with reference to the check valve 300, with the two design variants of the check valve 300 also being discussed in conclusion.Furthermore, throttle valves 100 and a further check valve 98 are also present in the second hydraulic connection 94.

[0079] Possible processes of operation of this in Fig. 10 The illustrated door drive 200 according to the invention is described below. Without operation of the hydraulic pump 10, the door drive 200 according to the invention can be operated as a normal hydraulically damped door closer. An opening movement of the door leads to a displacement of the drive piston 220 against the force of the closer spring 224, with hydraulic fluid 102 simultaneously flowing from the spring chamber 216 into the pressure chamber 214 via the drive piston interior 222 and the fourth hydraulic line 104.

[0080] Depending on the setting of the electrically switchable shut-off valve 300, two possibilities arise. When the shut-off valve 300 is closed, the hydraulic structure of the door drive 200 according to the invention holds the drive piston 220 in its deflected position following the deflection, since the hydraulic fluid 102 is prevented from flowing out of the pressure chamber 214. A freewheel 226 (cf. Fig. 1 ) which in this case still allows the door to move at least essentially without resistance.

[0081] Alternatively, the electrically switchable shut-off valve 300 can be opened to allow hydraulic fluid 102 to flow into the second hydraulic connection 94, so that when the door is released, the closing spring 224 pushes the drive piston 220 back to its initial position and, at the same time, hydraulic fluid 102 flows back into the spring chamber 216 via the second hydraulic connection 94. The two preferably adjustable throttle valves 100 arranged in the second hydraulic connection 94 and the additional check valve 98 ensure that the closing speed is adjusted, in particular to a precisely defined value (by means of the Fig. 10 right throttle valve 100 shown) and at the same time for a so-called final action functionality, where the door can be accelerated at the end of its closing movement to guarantee an absolutely safe closing of the door, for example by engaging a locking latch (by the Fig. 10 shown left throttle valve 100 and the check valve 98 present in the associated branch of the second hydraulic connection 94).

[0082] Alternatively, at least one hydraulic opening of the door is possible, driven by the hydraulic pump 10 of the door drive 200 according to the invention. In the following Fig. 11 bis 14 is the Fig. 10 shown embodiment of the door drive 200 according to the invention is shown in further illustrations, each of which shows only the hydraulic components required for the hydraulically driven operation of the door drive 200 according to the invention. For simplification and to avoid repetition, the hydraulically driven operation of the door drive 200 according to the invention is described below with reference to the Fig. 11 bis 14 With regard to features of the door drive 200 according to the invention not described below, reference is made to the above description, in particular the Fig. 10 , referred to.

[0083] Fig. 11 shows an initial state for the hydraulically driven operation of the door drive 200 according to the invention. The pump piston 50 is located in the fluid chamber 12 in such a position that a volume of the pump chamber 14 is maximized and a volume of the reserve chamber 16 is minimized. As the pressure side 20 of the hydraulic pump 10, the pump chamber 14 is connected to the pressure chamber 214 upstream of the drive piston 220 via the first hydraulic connection 92, in which a correspondingly arranged check valve 98 is located. A second hydraulic connection 94, in which the electrically switchable shut-off valve 300 is arranged, connects the pressure chamber 214 to the spring chamber 216, wherein a flow of the hydraulic fluid 102 can be regulated via a throttle valve 100 in this second hydraulic connection 94. The spring chamber 216, in which in particular the closing spring 224 is also arranged, is in turn connected to the holding chamber 16 of the hydraulic pump 10 via a third hydraulic connection 96.For the resetting of the pump piston 50, which is also described below (see . Fig. 13 ) it also has in particular a connecting line 60 with a check valve 98.

[0084] Fig. 12 shows a hydraulically or electrohydraulically driven displacement of the drive piston 220 against the force of the closing spring 224. For this purpose, the pump piston 50, driven by the motor unit 30, was displaced in the fluid chamber 12 and thereby the hydraulic fluid 102 present in the pump chamber 14 was pumped into the pressure chamber 214. Since the electrically switchable shut-off valve 300 is closed, this leads to a displacement of the drive piston 220 in the direction of its open position and thus, for example, to an opening movement of the door and / or to a pretensioning of the closing spring 224. This open position of the drive piston 220 can, for example, correspond to an opening angle of the door between greater than 0° and 180°, in particular between 75° and 105°, preferably 90°.At the same time, the displacement of the drive piston 220 reduces the spring chamber 216, whereby hydraulic fluid 102 is automatically pressed from the spring chamber 216 via the third hydraulic connection 96 into the holding chamber 16 of the hydraulic pump 10, which is connected to the suction side 22 of the hydraulic pump 10.

[0085] In order to perform a new stroke with the pump piston 50, it must be reset inside the hydraulic pump 10. This is Fig. 13 shown. Driven by the motor unit 30, the pump piston 50 is displaced in the fluid chamber 12 such that the volume of the pump chamber 14 increases again and, at the same time, the volume of the reserve chamber 16 decreases. The hydraulic fluid 102 thus displaced from the reserve chamber 16 flows into the pump chamber 14 via the connecting line 60 and the correspondingly arranged check valve 98. In this way, it is possible, for example, to reach the open position of the drive piston 220 using multiple strokes of the pump piston 50 or to expand the possible achievable range of open positions of the drive piston 220.

[0086] Fig. 14 now shows the state of the door drive 200 according to the invention, when starting from the state of Fig. 13the electrically switchable shut-off valve 300 is opened. Hydraulic fluid 102 can flow from the pressure chamber 214 via the second hydraulic connection 94 and the throttle valve 100 arranged therein into the spring chamber 216. The drive piston 220 is thus pushed back into its initial position, in particular by the mechanical energy stored in the closing spring 224.

[0087] Preferably, it can be provided, in particular, that this open state of the electrically switchable shut-off valve 300 is also assumed when the shut-off valve 300 is de-energized. In other words, the shut-off valve 300 is closed when energized. In particular, a displacement of the drive piston 220 into its initial position can thus be ensured even in the event of a power failure. Use of the door drive 200 according to the invention on fire doors for which the closing or keeping of the corresponding door closed must be ensured in the event of a fire, in particular even in the event of a power failure during a fire, can be enabled.

[0088] Alternatively, the electrically switchable shut-off valve 300 can also be designed such that it is open when energized and remains closed when de-energized. In this case, it can be ensured that the drive piston 220 remains in this deflected position even in the event of a power failure after previously performed hydraulic deflection. This makes it possible to keep the corresponding door open, for example, as an escape route or as an air supply for a smoke and heat extraction system. List of reference symbols

[0089] 10Hydraulic pump 12Fluid chamber 14Pump chamber 16Reservoir chamber 18Wall 20Discharge side 22Suction side 30Motor unit 32Drive shaft 34Drive section 36Electric motor 38Gearbox 40Bearing cap 42Bearing 50Pump piston 52Piston plate 54Spindle section 56Sealing element 60Connecting line 62Bypass line 70Threaded connection 72Threaded spindle 74Holding area 76Threaded nut 78Internal thread 80External thread 82Tooth root area 84Tooth tip area 90Hydraulic system 92First hydraulic connection 94Second hydraulic connection 96Third hydraulic connection 98Check valve 100Throttle valve 102Hydraulic fluid 104Fourth hydraulic connection 110Disc element 112Spring plate 114Sleeve 116Sleeve chamber 200Door drive 202Hood 210 Housing 212 Hydraulic cylinder 214 Pressure chamber 216 Spring chamber 218 Drive mechanism 220 Drive piston 222 Drive piston interior 224 Closing spring 226 Freewheel 228 Drive shaft 230 Linkage 300Shut-off valve

Claims

1. Door drive (200) for a door, having a housing (210) with a hydraulic cylinder (212), a drive mechanism (218) which is able to be coupled to the door and is disposed in the hydraulic cylinder (212) and has a displaceable drive piston (220) and a closer spring (224) which impinges the drive piston (220) in the closing direction of the door, wherein formed on the side of the drive piston (220) that lies opposite the closer spring (224) is a pressure chamber (214) for impinging the drive piston (220) with a hydraulic fluid (102) in the opening direction of the door, a hydraulic system (90), and a hydraulic pump (10) for conveying the hydraulic fluid (102) to the pressure chamber (214), wherein the hydraulic pump (10) is designed as a piston pump having a pump piston (50) which is axially displaceable and co-rotationally disposed in a fluid chamber (12) and is sealed in relation to a wall (18) of the fluid chamber (12) and delimits a pump chamber (14) which is connected to the pressure side (20) of the hydraulic pump (10), wherein the hydraulic system (90) has a first hydraulic connection (92) which connects the pump chamber (14) to the pressure chamber (214), wherein the hydraulic pump (10) comprises an electric motor unit (30) having a drive shaft (32), and a drive portion (34) of the drive shaft (32) is coupled to the pump piston (50) via a threaded connection (70) in order to axially displace the pump piston (50) in the fluid chamber (12) and thereby perform a stroke of the pump piston (50), wherein the hydraulic system (90) has a second hydraulic connection (94) which connects the pressure chamber (214) to a spring chamber (216) in which the closer spring (224) is disposed, wherein in the second hydraulic connection (94) there is an electrically switchable shut-off valve (300) for selectively releasing or preventing a flow from the pressure chamber (214) into the spring chamber (216) and thus for moving the drive piston (220) in the closing direction, characterized in that the fluid chamber (12) and the spring chamber (216) are separated by a disc element (110), wherein the disc element (110) has a sleeve (114) which is closed towards the spring chamber (216) and extends into the spring chamber (216) and encloses a sleeve chamber (116), wherein the sleeve chamber (116) is contiguous to the fluid chamber (12) without walls, thus enlarging the fluid chamber (12) by the sleeve chamber (116), wherein the seal of the pump piston (50) in relation to the wall (18) of the fluid chamber (12) is disposed on an end of the pump piston (50) facing the motor unit (30), and a portion of the pump piston (50) extends at least temporarily into the sleeve chamber (116) during the operation of the hydraulic pump (10).

2. Door drive (200) for a door, having a housing (210) with a hydraulic cylinder (212), a drive mechanism (218) which is able to be coupled to the door and is disposed in the hydraulic cylinder (212) and has a displaceable drive piston (220) and a closer spring (224) which impinges the drive piston (220) in the closing direction of the door, wherein formed on the side of the drive piston (220) that lies opposite the closer spring (224) is a pressure chamber (214) for impinging the drive piston (220) with a hydraulic fluid (102) in the opening direction of the door, a hydraulic system (90), and a hydraulic pump (10) for conveying the hydraulic fluid (102) to the pressure chamber (214), wherein the hydraulic pump (10) is designed as a piston pump having a pump piston (50) which is axially displaceable and co-rotationally disposed in a fluid chamber (12) and is sealed in relation to a wall (18) of the fluid chamber (12) and delimits a pump chamber (14) which is connected to the pressure side (20) of the hydraulic pump (10), wherein the hydraulic system (90) has a first hydraulic connection (92) which connects the pump chamber (14) to the pressure chamber (214), wherein the hydraulic pump (10) comprises an electric motor unit (30) having a drive shaft (32), and a drive portion (34) of the drive shaft (32) is coupled to the pump piston (50) via a threaded connection (70) in order to axially displace the pump piston (50) in the fluid chamber (12) and thereby perform a stroke of the pump piston (50), wherein the hydraulic system (90) has a second hydraulic connection (94) which connects the pressure chamber (214) to a spring chamber (216) in which the closer spring (224) is disposed, wherein in the second hydraulic connection (94) there is an electrically switchable shut-off valve (300) for selectively releasing or preventing a flow from the pressure chamber (214) into the spring chamber (216) and thus for moving the drive piston (220) in the closing direction, characterized in that the fluid chamber (12) and the spring chamber (216) are mutually contiguous without walls, wherein the seal of the pump piston (50) in relation to the wall (18) of the fluid chamber (12) is disposed on an end of the pump piston (50) facing the motor unit (30), and a portion of the pump piston (50) extends at least temporarily into the spring chamber (216) during the operation of the hydraulic pump (10).

3. Door drive (200) according to Claim 1 or 2, characterized in that an axis of the threaded connection (70) is offset from a central axis of the pump piston (50) in order to co-rotationally dispose the pump piston (50) in the fluid chamber (12).

4. Door drive (200) according to one of Claims 1 to 3, characterized in that, for co-rotationally disposing the pump piston (50) in the fluid chamber (12), the pump piston (50) is mounted in the fluid chamber (12) in a form-fitting manner in the circumferential direction, in particular wherein the pump piston (50) and the wall (18) of the fluid chamber (12) have a shape differing from a circle and / or wherein a guide groove is provided on the pump piston (50) and a corresponding guide pin is provided on the wall (18) of the fluid chamber (12), or vice versa.

5. Door drive (200) according to one of the preceding claims, characterized in that the threaded connection (70) is designed as a trapezoidal thread, a buttress thread, a ball thread or a roller thread.

6. Door drive (200) according to one of the preceding claims, characterized in that, for the threaded connection (70), the drive portion (34) is formed as a threaded spindle (72) having an external thread (80), and the pump piston (50) has a receptacle region (74), preferably a receptacle bore, for receiving the threaded spindle (72), wherein the receptacle region (74) is formed at least in portions as a threaded nut (76) having a corresponding internal thread (78), wherein the threaded nut (76) is preferably disposed on an end of the pump piston (50) facing the motor unit (30).

7. Door drive (200) according to one of preceding Claims 1 to 5, characterized in that the pump piston (50) has a piston plate (52) which is sealed in relation to the axial wall (18) of the fluid chamber (12), and a spindle portion (54) which is disposed on the piston plate (52), wherein for the threaded connection (70) the spindle portion (54) is formed as a threaded spindle (72) having an external thread (80), and the drive portion (34) has a cylindrical receptacle region (74), preferably a receptacle bore formed as a blind bore, for receiving the spindle portion (54), wherein the receptacle region (74) is formed at least in portions as a threaded nut (76) having a corresponding internal thread (78), wherein preferably the threaded nut (76) is disposed on an end of the receptacle region (74) facing away from the motor unit (30).

8. Door drive (200) according to one of the preceding claims, characterized in that, for sealing in relation to the axial wall (18) of the fluid chamber (12), a sealing element (56), in particular comprising an O-ring and a piston sealing ring, is disposed on the pump piston (50) so as to encircle the latter.

9. Door drive (200) according to one of the preceding claims, characterized in that the drive piston (220) is displaceable, counter to the force of the closer spring (224), to an opening position by a single stroke or a plurality of strokes, preferably a single stroke, of the pump piston (50).

10. Door drive (200) according to Claim 9, characterized in that, in the assembled state of the door drive (200), the opening position of the drive piston (220) corresponds to an opening angle of the door of between more than 0° and 180°, in particular between 75° and 105°, preferably of 90°.

11. Door drive (200) according to one of preceding Claims 9 or 10, characterized in that the door drive (200) has a freewheel (226) coupled to the drive mechanism (218), wherein the freewheel (226) decouples a movement of the door from a movement of the drive piston (220) in order to enable a freewheel functionality in the mounted state of the door drive (200) after the drive piston (220) has reached the opening position, and for the duration in which the drive piston (220) is disposed in the opening position.

12. Door drive (200) according to one of the preceding claims, characterized in that the pump piston (50) is disposed in the fluid chamber (12) between the pump chamber (14) and the motor unit (30), as a result of which a pressing movement of the pump piston (50) leads to the drive piston (220) being impinged with the hydraulic fluid (102) in the opening direction in the pressure chamber (214).

13. Door drive (200) according to one of preceding Claims 1 to 11, characterized in that the pump chamber (14) is formed in the fluid chamber (12) between the pump piston (50) and the motor unit (30), as a result of which a pulling movement of the pump piston (50) leads to the drive piston (220) being impinged with the hydraulic fluid (102) in the opening direction in the pressure chamber (214).

14. Door drive (200) according to one of the preceding claims, characterized in that the pump chamber (14) is connected to the pressure side (20) and to the suction side (22) of the hydraulic pump (10), wherein it is preferably provided that the pressure side (20) and the suction side (22) each have a check valve (98), wherein in a pumping movement of the pump piston (50) the check valve (98) of the pressure side (20) opens and the check valve (98) of the suction side (22) closes, and in a suction movement of the pump piston (50) the check valve (98) of the pressure side (20) closes and the check valve (98) of the suction side (22) opens.

15. Door drive (200) according to one of preceding Claims 1 to 13, characterized in that the pump piston (50) on its side opposite the pump chamber (14) in the fluid chamber (12) delimits a reservoir chamber (16) connected to the suction side (22) of the hydraulic pump (10), wherein disposed in the pump piston (50) is a connecting line (60) having a check valve (98) for a flow of hydraulic fluid (102) from the reservoir chamber (16) into the pump chamber (14) when the pump piston (50) moves in the direction of the reservoir chamber (16).

16. Door drive (200) according to Claim 15 and Claim 6, characterized in that the connecting line (60) ends in the receptacle region (74) and for a flow of the hydraulic fluid (102) past the threaded connection (70) into the receptacle region (74) of the pump piston (50) has a bypass line (62), and / or the external thread (80) and / or the internal thread (78) of the threaded connection (70) have / has a recessed tooth base region (82) and / or a shortened tooth crest region (84).

17. Door drive (200) according to Claim 15 and Claim 7, characterized in that the connecting line (60) is disposed in the piston plate (52).

18. Door drive (200) according to one of the preceding claims, characterized in that a check valve (98) to prevent a flow of hydraulic fluid (102) from the pressure chamber (214) to the pump chamber (14) is disposed in the first hydraulic connection (92).

19. Door drive (200) according to one of the preceding claims, characterized in that at least one throttle valve (100) for hydraulically damping the movement of the drive piston (220) in the closing direction is disposed in the second hydraulic connection (94).

20. Door drive (200) according to one of the preceding claims, characterized in that the electrically switchable shut-off valve (300) is open in a de-energized state and releases a flow of hydraulic fluid (102) from the pressure chamber (214) into the second hydraulic connection (94).

21. Door drive (200) according to one of the preceding claims, characterized in that the electrically switchable shut-off valve (300) is blocked in a de-energized state and prevents a flow of hydraulic fluid (102) from the pressure chamber (214) into the second hydraulic connection (94).

22. Door drive (200) according to Claim 1 or one of Claims 3 to 21, if referring back to Claim 1, characterized in that the hydraulic system (90) has a third hydraulic connection (96) which connects the spring chamber (216) to the fluid chamber (12), in particular the pump chamber (14) or the reservoir chamber (16), wherein the third hydraulic connection (96) enables a flow of hydraulic fluid (102) from the spring chamber (216) into the fluid chamber (12) when the drive piston (220) is displaced in the opening direction.

23. Door drive (200) according to one of the preceding claims, characterized in that the first hydraulic connection (92) and / or the second hydraulic connection (94) and / or the third hydraulic connection (96) are / is formed at least in portions as a bore, in particular a deep bore, in the housing (210) of the door drive (200).

24. Door drive (200) according to one of the preceding claims, characterized in that the fluid chamber (12) on a side facing the electric motor unit (30) is delimited by a bearing cover (40), wherein the bearing cover (40) has a bearing (42) in which the drive shaft (32) is axially fixed and radially mounted, wherein preferably the bearing cover (40) seals the fluid chamber (12) in relation to the environment.

25. Door drive (200) according to one of the preceding claims, characterized in that the electric motor unit (30) comprises a stepper motor and a planetary gear (38) and / or a cycloidal gear (38), wherein preferably the electric motor unit (30) is disposed outside the housing (210) and is fastened to the housing (210), in particular to a housing cover.

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