Door closer

Abstract

Door closer (10) for automatically closing a door, comprising a housing (12), a drive shaft (30) coupling to the door, a mechanical energy storage device (60) chargeable by linear deflection (94), and a drive mechanism (20) for bidirectional mechanical interaction of the drive shaft (30) and the mechanical energy storage device (60) such that a rotation of the drive shaft (30) in an opening direction (90) corresponding to an opening movement of the door leads to charging of the mechanical energy storage device (60), and conversely, a discharge of the mechanical energy storage device (60) leads to a rotation of the drive shaft (30) in a closing direction (92) opposite to the opening direction (90), characterized in that that the drive mechanism (20) comprises a first gear (22), a second gear (24) toothed with the first gear (22) and a transmission shaft (32), wherein the first gear (22) is connected to the drive shaft (30) and the second gear (24) is connected to the transmission shaft (32) in a rotationally fixed manner, and wherein the drive mechanism (20) comprises a spindle drive (50) with a spindle (34) and a spindle nut (40), wherein the transmission shaft (32) comprises the spindle (34), wherein a rotation of the transmission shaft (32) results in a linear movement of the spindle nut (40) and conversely a linear movement of the spindle nut (40) results in a rotation of the transmission shaft (32), and wherein for charging and discharging the mechanical energy storage device (60) the spindle nut (40) is mechanically operatively connected to the mechanical energy storage device (60).

Description

[0001] The invention relates to a door closer for automatically closing a door, comprising a housing, a drive shaft that can be coupled to the door, a mechanical energy storage device that can be charged by linear deflection, and a drive mechanism for bidirectional mechanical interaction of the drive shaft and the mechanical energy storage device such that a rotation of the drive shaft in an opening direction corresponding to an opening movement of the door leads to a charging of the mechanical energy storage device, and conversely, a discharge of the mechanical energy storage device leads to a rotation of the drive shaft in a closing direction opposite to the opening direction.

[0002] Automatic door closers, which ensure the closing of a swinging door leaf after the door has been opened, primarily through purely mechanical means, are known in the prior art. Such door closers, often housed in a casing, comprise a drive mechanism and a mechanical energy storage device that is charged with mechanical energy, particularly potential energy, during the door's opening process. After the door is released, this stored mechanical energy is then used to drive the closing mechanism of the door.

[0003] DE 10 2006 012 757 A1 relates to a door actuation device, in particular for a revolving door, with a drive unit which can be coupled to a door and is arranged in a housing, further comprising a spring force storage device in which at least the energy required to execute the closing movement of the door can be stored and which has at least one compression spring arranged under a spring preload, wherein the spring preload of the compression spring is adjustable by means of a spring adjustment.

[0004] DE 10 2014 212 351 A1 relates to a drive device for a revolving door with a motor for opening the door and a spring accumulator for closing the door, wherein the motor acts against a spring force of the spring accumulator, and wherein an opening or closing force acts via a drive spindle and a spindle nut on a toothed piston which meshes with a pinion non-rotatably connected to an output shaft. A single-acting clutch is arranged between the motor and the drive spindle, which interrupts the power flow between the motor and the drive spindle when an additional torque acting in the opening direction is applied to the output shaft.

[0005] The mechanical energy storage devices in common door closers are often springs that are compressed to charge with mechanical energy. In other words, it is necessary to convert the rotational movement of the door leaf into a linear movement to charge the energy storage device.

[0006] To achieve this, the drive mechanisms of known state-of-the-art door closers often incorporate mechanical elements that convert the rotary motion of a drive shaft, coupled to the rotation of the door, into the linear displacement of a piston, which is guided linearly within the door closer and is part of the drive mechanism. The piston, in turn, charges the mechanical energy storage device. Possible configurations of these mechanical elements include, for example, a gear element that is rotationally fixed to the drive shaft and meshes with a rack element, which is either fixed to the piston or formed integrally with it.

[0007] A disadvantage of these known, state-of-the-art door closers is that such a piston requires a significant amount of installation space. The piston is moved from a rest position when the door is closed to a deflected position when the door is open. This necessitates providing space not only for the piston itself, but also for its entire travel distance.

[0008] It is therefore an object of the present invention to at least partially overcome the disadvantages of known door closers of the prior art described above. In particular, it is an object of the present invention to create a door closer whose drive mechanism requires a particularly small installation space and which can be designed in a particularly compact manner overall.

[0009] The aforementioned problem is solved by the claims. In particular, the problem is solved by a door closer having the features of independent claim 1. Further features and advantages of the door closer according to the invention will become apparent from the dependent claims, the description, and the drawing.

[0010] According to the invention, the problem is solved by a door closer for automatically closing a door, comprising a housing, a drive shaft that can be coupled to the door, a mechanical energy storage device that can be charged by linear deflection, and a drive mechanism for bidirectional mechanical interaction of the drive shaft and the mechanical energy storage device such that a rotation of the drive shaft in an opening direction corresponding to an opening movement of the door leads to a charging of the mechanical energy storage device, and conversely, a discharge of the mechanical energy storage device leads to a rotation of the drive shaft in a closing direction opposite to the opening direction.The door closer according to the invention is characterized in that the drive mechanism comprises a first gear, a second gear toothed with the first gear and a transmission shaft, wherein the first gear is connected to the drive shaft and the second gear to the transmission shaft in a rotationally fixed manner, and wherein the drive mechanism has a spindle drive with a spindle and a spindle nut, wherein the transmission shaft has the spindle, wherein a rotation of the transmission shaft leads to a linear movement of the spindle nut and conversely a linear movement of the spindle nut leads to a rotation of the transmission shaft, and wherein for charging and discharging the mechanical energy storage device the spindle nut is mechanically connected to the mechanical energy storage device.

[0011] A door closer according to the invention provides the functions of a mechanical door closer. A drive shaft of the door closer is coupled to the door, which can be designed as a swing door, or to a door leaf of this door. Preferably, a shaft passage for the drive shaft is provided in a housing of the door closer. Furthermore, a drive mechanism is arranged in the housing, which bidirectionally couples a rotary movement of the drive shaft, which accompanies the opening and closing of the door, with a linearly actuated mechanical energy storage device. In other words, an opening movement of the door, for example performed by a user, leads to the charging of the linearly deflectable mechanical energy storage device.The potential energy present and stored in the mechanical energy storage device then leads, after the door is released, to a linear effect on the drive mechanism when the energy storage device relaxes or discharges, whereby the drive mechanism converts this into a rotary movement of the drive shaft, so that the door closes automatically again.

[0012] The essential aspect of the invention is the design of the drive mechanism of the door closer according to the invention. In particular, the drive mechanism comprises two interlocking gears, the first gear being non-rotatably connected to the drive shaft and the second gear being non-rotatably connected to a transmission shaft of the drive mechanism. Thus, a rotary motion of the drive shaft is converted into a rotary motion of the transmission shaft, and vice versa, in a particularly simple manner. Gears within the meaning of the invention need not be complete gears; elements comprising a suitably designed and dimensioned gear section can also be considered gears of the door closer according to the invention.

[0013] The use of two gears, for example, allows for a gear ratio between the drive shaft and the transmission shaft. It also enables the drive shaft's axis of rotation to be oriented differently from the transmission shaft's axis of rotation. This allows, for instance, the drive shaft's axis of rotation to be selected to best suit its coupling to the door, and / or the transmission shaft's axis of rotation to be optimized for its function within the drive mechanism.

[0014] Furthermore, the drive mechanism features a spindle drive with a spindle and a spindle nut. The spindle drive is the section of the drive mechanism that bidirectionally converts rotary and linear motion into one another. A spindle drive is characterized in particular by being free of self-locking or essentially free of self-locking. In other words, the spindle drive operates bidirectionally: a rotary motion of the spindle causes a linear motion of the spindle nut along the spindle, and conversely, a linear motion of the spindle nut causes a rotary motion of the spindle. The spindle nut moves along the spindle, allowing the spindle length to be designed to accommodate the maximum required range of motion of the spindle nut. This maximum required range of motion also determines the installation space required in the longitudinal direction for the entire spindle drive.This allows for a particularly compact design of the spindle drive and thus of the entire drive mechanism.

[0015] Furthermore, in the door closer according to the invention, the mechanical energy storage device is mechanically operatively connected to the spindle nut of the drive mechanism. As explained above, the mechanical energy storage device can be charged by linear displacement. This is made particularly easy by the mechanical operative connection with the spindle nut, which itself also moves linearly. The discharge of the mechanical energy storage device, which also involves a linear movement, can likewise be transmitted via this mechanical operative connection to the spindle nut, and further via the spindle drive and the two gears to the drive shaft.

[0016] In summary, the drive mechanism of the door closer according to the invention enables a simple and, in particular, a very compact design of the door closer with minimal installation space requirements. For example, the use of the spindle drive eliminates the need for additional installation space that would otherwise be required for a sliding movement of a piston inside the door closer.

[0017] Furthermore, the door closer according to the invention can be designed such that the transmission shaft is arranged at an angle to the drive shaft within the housing, in particular at an angle between 60° and 120°, preferably at an angle of 90°. An angled arrangement makes it possible, in particular, to ensure that the axes of rotation of the drive shaft and the transmission shaft do not have to be aligned parallel to each other. In particular, an arrangement angle of 90° allows the longitudinal extension of the door closer according to the invention to be aligned along an edge of the door, thereby utilizing a normally available installation space, for example above the door, and creating a user-friendly appearance of the installed door closer.

[0018] The door closer according to the invention can also be further developed by using bevel gears for the first and second gears. Bevel gears make it particularly easy to arrange the drive shaft and the transmission shaft at an angle to each other. At the same time, bevel gears still allow for an even load distribution between the gears, which is not the case with an alternative design of the gears as a crown gear and a spur gear.

[0019] In a further embodiment of the door closer according to the invention, the first and second gears can be asymmetrically matched gears. Asymmetrical gears within the meaning of the invention are, in particular, gears whose teeth do not all have the same radius with respect to their respective axes of rotation. However, such asymmetrical gears of the door closer according to the invention are simultaneously matched to each other, so that the meshing of the two gears is maintained or ensured at all times and for all angles of rotation. In this way, a continuous mechanical connection between the drive shaft and the mechanical energy storage device is maintained. Furthermore, the asymmetry of the gears enables a gear ratio that is dependent on the angle of rotation.In this way, for example, a particularly simple angle-dependent control of the closing speed can be provided. Setting, for example, a maximum opening angle or an opening resistance dependent on an opening angle is also conceivable.

[0020] Furthermore, the door closer according to the invention can be characterized in that the spindle drive comprises a ball screw drive. In a ball screw drive, balls are arranged between the spindle and the spindle nut. This minimizes friction occurring during operation of the spindle drive. In this way, complex measures for internal lubrication of the drive mechanism can be dispensed with, or the necessary lubrication devices can at least be significantly simplified and reduced. In particular, a ball screw drive enables a particularly simple and reliable self-locking design of the spindle drive.

[0021] Furthermore, the door closer according to the invention can be provided with a mechanical energy storage device comprising a coil spring, wherein the spindle nut includes a spring plate on which the coil spring is supported. Coil springs are particularly suitable as mechanical energy storage devices because they can be manufactured cost-effectively in many variants adaptable to a wide variety of requirements. In particular, a coil spring with high spring stiffness allows for the storage of a large amount of mechanical energy while requiring minimal installation space. This further increases the achievable compactness of the door closer according to the invention. The spring plate on which the coil spring is supported can be fixed to the spindle nut as an additional element. Preferably, however, the spring plate is formed integrally with the spindle nut, for example, as a circumferential projection on a base body of the spindle nut.

[0022] According to a further development of the door closer according to the invention, it can also be provided that the spindle drive is at least partially enclosed by the coil spring. Coil springs usually have a helical shape, leaving a free volume in the middle of the coil spring. By arranging the spindle drive at least partially in this free volume, the installation space available in the door closer according to the invention can be utilized even more efficiently. This can result in a further reduction of the installation space required for the door closer according to the invention.

[0023] Furthermore, the door closer according to the invention can be designed such that it includes a controllable electromagnet for holding the mechanical energy storage device in its charged state. In other words, such an electromagnet can keep the energy storage device charged, and thus the corresponding door open. The electromagnet can be provided in the door closer according to the invention in such a way that it can interact with an element of the drive mechanism, for example, the spindle nut, the spindle, and / or the transmission shaft, so that this element is blocked against movement, particularly movement coupled with a closing movement of the door. The controllability of the electromagnet then allows the blocked state to be selectively released, for example, only after a request and / or release by a user.

[0024] The door closer according to the invention can also be characterized in that it has a damping device for at least partially damping a door movement. A damping device makes it possible, in particular, to influence the release of the energy stored in the mechanical energy storage device in such a way that this can be specifically controlled. This prevents the door from slamming shut uncontrollably. For this purpose, the damping device is preferably mechanically connected to the drive shaft, the drive mechanism, and / or the mechanical energy storage device.In addition to influencing the closing process of the door as already mentioned above, a damping device in the door closer according to the invention can also act during an opening movement of the door, for example to generate a particularly high initial resistance when opening the door or to prevent the door from hitting a structural boundary at the end of the opening process.

[0025] According to a further development, the door closer according to the invention can be designed such that the damping device enables at least one of the following functionalities during the door movement: Final stroke Damping of closing speed Damping of an opening movement Setting a maximum opening angle

[0026] This list is not exhaustive, so the damping device of the door closer according to the invention can also provide or enable further functionalities. Overall, the operation of the door closer according to the invention, with the functionalities enabled by the damping device, can be configured in a wide variety of ways, thus allowing the properties of the door closer according to the invention to be adapted to a wide range of requirements.

[0027] In one embodiment of the door closer according to the invention, it can be further developed such that the damping device is coupled to the drive mechanism, in particular by coupling to the spindle nut. Coupling to the drive mechanism is mechanically particularly easy to implement, since, depending on the damping device used, coupling to either a rotating element, such as the transmission shaft, or a linearly moving element, such as the spindle nut, is possible. Since many embodiments of damping devices require linear actuation, coupling to the spindle nut is particularly preferred.

[0028] The door closer according to the invention can also be further developed by using a hydraulic damping device with a damping fluid guided in a damping fluid system. Hydraulic damping devices are particularly reliable damping devices whose use in door closers has proven successful. During operation, the damping fluid flows through the damping fluid system, with the specific design of the damping fluid system determining the properties of the damping device. In particular, valves can be provided as part of the damping fluid system, which, through their flow characteristics and especially their location within the damping fluid system, selectively influence the flow of the damping fluid and thus enable the various functionalities of the damping device.It is also preferable to provide that these valves can be operated from outside the door closer, so that it is possible to adjust the functionalities, for example a maximum closing speed.

[0029] Furthermore, the door closer according to the invention can be characterized in that a control piston arranged on the spindle nut is provided for coupling the damping device with the drive mechanism. This control piston is sealed and slidably engages in a control volume, preferably cylindrical, of the damping fluid system of the damping device. As described above, the functionalities of the hydraulic damping device are generated or effected by the flow of the damping fluid within the damping fluid system. A combination of control piston and control volume represents a particularly simple way of coupling the linear movement of the spindle nut, and thus ultimately the opening and closing movements of the door, with the damping device.When the spindle nut moves, the control piston inside the control volume is displaced, either displacing damping fluid from the piston or drawing it in. The flow of damping fluid within the damping system of the damping device is thus coupled to the movement of the spindle nut. This allows the functionalities provided by the damping device to be transferred to the door movement particularly easily and reliably.

[0030] The door closer according to the invention can further be designed such that the housing has at least one damping cavity, wherein the at least one damping cavity forms at least the damping fluid system, in particular at least the actuation volume. In other words, the damping fluid system can be integrated at least partially, preferably completely, into the housing of the door closer according to the invention. This eliminates the need for additional components with cavities for forming the damping fluid system, for example, pipes, reservoirs, or the like, or at least significantly reduces their number. In this way, the door closer according to the invention can not only be simpler but also more compact.

[0031] Furthermore, the door closer according to the invention can also be further developed such that the hydraulic damping device is a self-contained system, and / or that the drive mechanism is arranged in a closing chamber of the housing, wherein the closing chamber is free of damping fluid. A self-contained system within the meaning of the invention means, in particular, that the damping fluid is arranged exclusively within the damping device. This allows, firstly, the required amount of damping fluid to be reduced. Secondly, only the damping device, in particular the damping fluid system, needs to be sealed; complex seals of the entire door closer, in particular of the door closer housing, can be dispensed with. This also applies in particular to the design of the door closer with a closing chamber that is free of damping fluid.Preferably, the closing chamber is not only free of damping fluid, but generally free of fluids or liquids.

[0032] The invention is described below with reference to the figure.

[0033] It shows schematically: Fig. 1 a sectional view of a door closer according to the invention.

[0034] The figure shows a door closer 10 according to the invention. A drive shaft 30 can be coupled to a door (not shown) or its door leaf, so that an opening movement of the door is accompanied by a rotation of the drive shaft 30 in an opening direction 90, and conversely, a closing movement of the door is accompanied by a rotation of the drive shaft 30 in a closing direction 92. The drive shaft 30 passes through an opening or a shaft passage in a housing 12 of the door closer 10, in which it is supported by a needle bearing 36 in a friction-free or at least low-friction manner.

[0035] Inside the housing 12, particularly in a closing chamber 14, a mechanical energy storage device 60 and a drive mechanism 20 are arranged as essential components of the door closer 10 according to the invention. The drive mechanism 20 couples a rotary movement of the drive shaft 30 with a corresponding movement or deflection 94 of the energy storage device 60. In the illustrated embodiment, the energy storage device 60 is designed as a coil spring 62, so that a linear deflection 94 caused by the drive mechanism 20 leads to the charging or discharging of the energy storage device 60, i.e., to a tensioning or relaxation of the coil spring 62.

[0036] In particular, the drive mechanism 20 is designed such that the coupling of the movements of the drive shaft 30 and the energy storage device 60 described above is bidirectional. In other words, a rotation of the drive shaft 30 in the opening direction 90 leads to a corresponding deflection 94 for tensioning the coil spring 62, and an opposite relaxation of the coil spring 62 and the associated opposite deflection 94 in turn leads to a rotation of the drive shaft 30 in the closing direction 92.

[0037] To fulfill this bidirectionality, a fundamental requirement for door closers 10, the drive mechanism 20 comprises several components. A first gear 22 is fixedly mounted on the drive shaft 30 and meshes with a second gear 24, which is also fixedly mounted on a transmission shaft 32. Both gears 22 and 24 are designed as bevel gears 26. This allows for a particularly simple angled arrangement of the transmission shaft 32 relative to the drive shaft 30, preferably at 90° as shown. In particular, the two bevel gears 26 are also asymmetrically designed to match each other, ensuring, on the one hand, that the meshing of the two gears 22 and 24 is maintained for all angles of rotation of the drive shaft 30 and the transmission shaft 32, respectively, and, on the other hand, enabling a rotation-angle-dependent gear ratio.This makes it possible to provide functionalities of the door closer 10 according to the invention that are adapted to different opening angles of the door, for example an opening angle-dependent closing speed.

[0038] As shown, the transmission shaft 32 extends over a large part of the closing chamber 14, being supported at two points in the closing chamber 14 by a ball bearing 38. In the illustrated embodiment, the transmission shaft 32 is continuous and one-piece; however, alternative embodiments with a multi-part, composite transmission shaft 32 are also conceivable.

[0039] According to the invention, a spindle drive 50 is provided to convert the rotary motion of the transmission shaft 32 into a linear deflection 94 effective for the energy storage device 60. The spindle drive 50 comprises, in particular, a spindle 34 formed by the transmission shaft 32 itself. This can be achieved, as shown, by a helical recess on the transmission shaft 32. Alternatively, the spindle 34 can also be attached to the transmission shaft 32 as a sleeve-like additional component or itself form a section of a multi-part transmission shaft 32.

[0040] As a further essential component, the spindle drive 50 has a spindle nut 40, which is mounted externally on the spindle 34. Through the interaction of the spindle 34 with the spindle nut 40, a rotation of the spindle 34 is bidirectionally converted into a linear movement of the spindle nut 40, and vice versa. In the illustrated and particularly preferred embodiment, the spindle drive 50 is designed as a ball screw drive 52. In this embodiment, both the spindle 34 and the spindle nut 40 each have a helical recess in which threaded balls 54 are guided. For clarity, only one of the threaded balls 54 is provided with a reference numeral.The threaded balls 54 provide, firstly, the mechanical coupling between the spindle 34 and the spindle nut 40, and secondly, they reduce friction and, in particular, ensure that the spindle drive 50 is designed to be free of self-locking or at least to have low self-locking properties.

[0041] As described above, in the illustrated embodiment, the mechanical energy storage device 60 is designed as a coil spring 62. This makes it possible, in particular, to arrange at least parts of the spindle drive 50 inside the coil spring 62, thereby saving further installation space. To transmit the linear movement of the spindle nut 40 to the coil spring 62, the spindle nut 40 includes a spring plate 42 on which the coil spring 62 rests. As shown, the spring plate 42 can be formed integrally with the rest of the spindle nut 40. Alternatively, a multi-part design is also conceivable, in which the spring plate 42 is then attached to the rest of the spindle nut 40 as an additional component.

[0042] Furthermore, as shown, a closing force adjustment 64 can be provided, with which a preload of the spiral spring 62 can be changed.

[0043] Furthermore, the door closer 10 according to the invention, in the illustrated embodiment, has a hydraulic damping device 70 which is coupled to the drive mechanism 20. For this purpose, a control piston 80 is arranged on the spindle nut 40, which engages displaceably and in a sealed manner in a control volume 82. The control volume 82 is part of a damping fluid system 74 of the damping device 80 and, like it, is filled with a damping fluid 72. A movement of the spindle nut 40 or a deflection 94 of the energy storage device 60 thus leads to a displacement of the control piston 80 in the control volume 82, which causes the damping fluid 72 to flow in the damping fluid system 74 of the damping device 70.By appropriately designing the damping fluid system 74, for example by using valves, a variety of functionalities can be provided during the door movement, such as a final stop, damping or setting of a closing speed, damping of an opening movement and / or setting of a maximum opening angle.

[0044] The compactness of the entire door closer 10 according to the invention is further increased in the illustrated embodiment, in particular by the fact that at least parts of the damping fluid system 74 are formed by a damping cavity 76, which is located directly in the housing 12 of the door closer 10. As shown, it is also preferably provided that the hydraulic damping device 70 constitutes a self-contained system. Such a closed system requires significantly less effort to seal than would be necessary to seal the entire housing 12 of the door closer 10. Equally important, this also allows the closing chamber 14 to be free of damping fluid 72.

[0045] In a further development not shown, the door closer 10 according to the invention can also include a switchable electromagnet. This can, for example, be arranged in the closer chamber 14 such that, at least when the door is open, and thus when the coil spring 62 is compressed to its maximum deflection 94, it can interact with an element of the drive mechanism 20, for example, the spindle nut 40, the spindle 34, and / or the transmission shaft 32. Preferably, the electromagnet can be provided as part of a separate assembly, which can, for example, be flanged inside or outside the housing 12 of the door closer 10. This also makes it possible to retrofit the door closer 10 with such an assembly including the electromagnet.The electromagnet, regardless of its installation position, directly or at least indirectly fixes the transmission shaft 32, and thus the entire drive mechanism 20, in the position described above and corresponding to the open door. In this way, the door equipped with the door closer 10 according to the invention can be held open. Upon manual or automatic triggering of the electromagnet, it releases the transmission shaft 32 again, and the door is closed again by the relaxing energy storage device 60. Reference symbol list 10 door closers 12 cases 14 Locker room 20 Drive Mechanics 22 First gear 24 Second gear 26 bevel gear 30 Drive shaft 32 transmission wave 34 Spindle 36 needle bearings 38 ball bearings 40 Spindle nut 42 spring plates 50 spindle gears 52 Ball screw drive 54 threaded ball 60 energy storage units 62 spiral spring 64 Closing force adjustment 70 Damping device 72 Damping fluid 74 Damping fluid system 76 Damping cavity 80 control pistons 82 control volume 90° opening direction 92 Closing direction 94 deflection

Claims

[1] Door closer (10) for automatically closing a door, comprising a housing (12), a drive shaft (30) that can be coupled to the door, a mechanical energy storage device (60) that can be charged by linear deflection (94), and a drive mechanism (20) for bidirectional mechanical interaction of the drive shaft (30) and the mechanical energy storage device (60) such that a rotation of the drive shaft (30) in an opening direction (90) corresponding to an opening movement of the door leads to charging of the mechanical energy storage device (60), and conversely, a discharge of the mechanical energy storage device (60) leads to a rotation of the drive shaft (30) in a closing direction (92) opposite to the opening direction (90), characterized by , that the drive mechanism (20) comprises a first gear (22), a second gear (24) toothed with the first gear (22) and a transmission shaft (32), wherein the first gear (22) is connected to the drive shaft (30) and the second gear (24) is connected to the transmission shaft (32) in a rotationally fixed manner, and wherein the drive mechanism (20) comprises a spindle drive (50) with a spindle (34) and a spindle nut (40), wherein the transmission shaft (32) comprises the spindle (34), wherein a rotation of the transmission shaft (32) results in a linear movement of the spindle nut (40) and conversely a linear movement of the spindle nut (40) results in a rotation of the transmission shaft (32), and wherein for charging and discharging the mechanical energy storage device (60) the spindle nut (40) is mechanically operatively connected to the mechanical energy storage device (60). [2] Door closer (10) according to claim 1, characterized by, that the transmission shaft (32) is arranged at an angle in the housing (12) with respect to the drive shaft (30), in particular at an angle between 60° and 120°, preferably at an angle of 90°. [3] Door closer (10) according to claim 1 or 2, characterized by , that the first gear (22) and the second gear (24) are bevel gears (26). [4] Door closer (10) according to any of the preceding claims, characterized by , that the first gear (22) and the second gear (24) are matched asymmetric gears (22, 24). [5] Door closer (10) according to any of the preceding claims, characterized by , that the spindle drive (50) includes a ball screw drive (52). [6] Door closer (10) according to any of the preceding claims, characterized by , that the mechanical energy storage device (60) comprises a coil spring (62), wherein the spindle nut (40) comprises a spring plate (42) on which the coil spring (62) is supported. [7] Door closer (10) according to claim 6, characterized by , that the spindle drive (50) is at least partially enclosed by the spiral spring (62). [8] Door closer (10) according to any of the preceding claims, characterized by , that the door closer (10) has a controllable electromagnet for keeping the mechanical energy storage device (60) in its charged state. [9] Door closer (10) according to any of the preceding claims, characterized by , that the door closer (10) has a damping device (70) for at least partially damping a door movement. [10] Door closer (10) according to claim 9, characterized by , that the damping device (70) enables at least one of the following functionalities during door movement: Final stroke Damping of closing speed Damping of opening movement Setting a maximum opening angle [11] Door closer (10) according to claim 9 or 10, characterized by , that the damping device (70) is coupled to the drive mechanism (20), in particular by a coupling to the spindle nut (40). [12] Door closer (10) according to one of claims 9 to 11, characterized by , that the damping device (70) is a hydraulic damping device (70) with a damping fluid (72) guided in a damping fluid system (74). [13] Door closer (10) according to claims 11 and 12, characterized by , that for coupling the damping device (70) with the drive mechanism (20) a control piston (80) arranged on the spindle nut (40) is provided, which engages in a sealed and displaceable manner in a control volume (82) of the damping fluid system (74) of the damping device (70), preferably cylindrical. [14] Door closer (10) according to claim 12 or 13, characterized by, that the housing (12) has at least one damping cavity (76), wherein the at least one damping cavity (76) forms at least sectionally the damping fluid system (74), in particular at least the control volume (82). [15] Door closer (10) according to one of claims 12 to 14, characterized by , that the hydraulic damping device (70) is a self-contained system, and / or that the drive mechanism (20) is arranged in a closing chamber (14) of the housing (12), wherein the closing chamber (14) is free of damping fluid (72).

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