Drive for a wing of a window or a door

Abstract

The invention relates to a drive for a sash of a window or door, in particular a door closer, comprising a drive mechanism for moving the sash, a drive housing in which the drive mechanism is at least partially arranged, a hydraulic fluid, in particular oil, which is contained in the drive housing, and a volume compensation element which is arranged within the drive housing, wherein the volume compensation element comprises an elastically compressible compensation body consisting of a closed-cell foam, in particular particle foam, a compensation housing with a housing opening into which the compensation body is inserted, and a closing element for closing the housing opening, wherein the closing element has a drain opening.through which the hydraulic fluid flows into the volume compensation element when the fluid temperature increases under compression of the compensating body and flows out of the volume compensation element when the fluid temperature decreases under expansion of the compensating body, and wherein the closure element has a flow-dependent check valve which closes the outflow opening when a back pressure of the hydraulic fluid occurring outside the volume compensation element exceeds a predetermined value, so that no hydraulic fluid can flow into the volume compensation element.

Description

[0001] The invention relates to a drive for a sash of a window or door, in particular a door closer, comprising a drive mechanism for moving the sash, a drive housing in which the drive mechanism is at least partially arranged, and a hydraulic fluid, in particular oil, which is contained in the drive housing.

[0002] The drive mechanism typically comprises an output shaft rotatably mounted around a pivot axis, a linearly displaceable piston coupled to the output shaft which rotates the output shaft when displaced, and a compression spring with a first end and a second end, which supports the piston with its first end and exerts a compression spring force on it.

[0003] Actuators for moving a window or door sash, especially door closers, are typically filled with a hydraulic fluid (usually oil) to achieve a defined damping characteristic. When the hydraulic fluid heats up, for example due to climatic conditions or a fire, it expands. Since hydraulic fluid is incompressible, this heating leads to a pressure increase within the actuator. At excessively high pressures, the actuator's seals can fail, causing the hydraulic fluid to leak. Furthermore, excessive pressure could also lead to the actuator bursting.

[0004] To prevent pressure increases, it is known to retain a small amount of air in the actuator. This air can be compressed when the hydraulic fluid expands, preventing an unacceptable pressure increase within the actuator. In such actuators, the air volume can compensate for volume changes in the hydraulic fluid that occur with temperature fluctuations of up to, for example, 70°C. However, a disadvantage is that the air interferes with the hydraulic functions of the actuator: because the air is compressed before a throttling pressure can build up, damping functions are sometimes delayed. This ultimately poses a risk to the operational reliability of the actuator. Furthermore, such actuators can no longer effectively compensate for volume changes in the hydraulic fluid that occur in a fire with significantly higher temperatures, thus increasing the risk of seal failure or even actuator bursting.

[0005] The invention is therefore based on the objective of creating a drive in which the disadvantages of the prior art do not occur, in particular in which the pressure within the drive does not rise impermissibly over a large temperature range, without disturbing the damping behavior.

[0006] This problem is solved by a drive with the features of claim 1, and in particular by the fact that the drive comprises a volume compensation element which is arranged within the drive housing, wherein the volume compensation element comprises an elastically compressible compensation body consisting of a closed-cell foam, in particular particle foam, a compensation housing with a housing opening into which the compensation body is inserted, and a closure element closing the housing opening, wherein the closure element has an outflow opening through which the hydraulic fluid flows into the volume compensation element under compression of the compensation body when the fluid temperature increases and flows out of the volume compensation element under expansion of the compensation body when the fluid temperature decreases, and wherein the closure element has a flow-dependent check valve.which closes the outflow opening when the back pressure of the hydraulic fluid occurring outside the volume compensation element exceeds a predetermined value, so that no hydraulic fluid can flow into the volume compensation element.

[0007] As the hydraulic fluid flows into the volume compensation element, the compensating body is compressed. This releases additional volume for the hydraulic fluid, preventing an increase in pressure within the drive. Because the compensating body is made of closed-cell foam, it cannot become saturated with hydraulic fluid and lose compressibility. Instead, the elastic closed-cell foam can be compressed particularly easily due to the gas trapped within its cavities. If the compensating body is damaged—for example, if a cavity ruptures after numerous compression and rebound cycles during operation—only a very small amount of gas can escape, which is essentially a negligible fraction of the total gas trapped within the compensating body.Consequently, the hydraulic function is not significantly affected even if the compensating element is damaged, thus increasing the reliability of the drive by using elastic closed-cell foam. A drive in which, for example, only a gas-filled elastic balloon was used for volume compensation would not offer this advantage, since all the gas would escape if the balloon were damaged.

[0008] The foam can be, for example, an expanded polyethylene cord or a molded element made of an expanded particle foam, such as expanded thermoplastic polyurethane.

[0009] In principle, the back pressure depends primarily on the flow velocity of the hydraulic fluid. During operation of the actuator, higher flow velocities occur due to piston movement than due to temperature-related volume changes of the hydraulic fluid. Since the flow-dependent check valve closes the outlet when the back pressure of the hydraulic fluid outside the volume compensation element exceeds a predetermined value (which is determined primarily by the back pressures occurring during actuator operation), sudden pressure increases, such as those that can occur when the impeller moves within the actuator, cannot affect the compensation element.In contrast, slow, temperature-related volume changes of the hydraulic fluid generally generate negligible back pressures below the specified value. At these pressures, the flow-dependent check valve does not close the outlet, allowing the hydraulic fluid to flow into the volume compensation element. Consequently, the flow-dependent check valve does not disrupt the hydraulic function during operation of the actuator, despite the volume compensation functionality it provides. Furthermore, it protects the compensation element itself from high pressures, resulting in a particularly long service life for the actuator.

[0010] In addition to the aforementioned advantages, the volume compensation element according to the invention is characterized by a simple design and easy assembly due to its construction, which ultimately also simplifies the design and assembly of the drive for realizing the volume compensation.

[0011] Advantageous embodiments of the invention will become apparent from the dependent claims, the description and the figures.

[0012] The compensating element may be provided with one or more recesses and / or protrusions on its surface, and / or the compensating housing on its inner wall, and / or the sealing element may have one or more recesses and / or protrusions, particularly channel-like, and / or a structure, particularly spherical, thereby forming one or more flow paths for the hydraulic fluid within the volume compensating element. The hydraulic fluid can reliably flow to the outlet of the sealing element via these flow paths. This prevents the compensating element from blocking the outlet—for example, in certain positions of the actuator—which would prevent the hydraulic fluid from flowing into the volume compensating element. It also prevents the hydraulic fluid from becoming trapped within the volume compensating element. Consequently, the provision of these flow paths increases the operational reliability and dependability of the actuator.Furthermore, hydraulic fluid flowing into the volume compensation element can reliably distribute itself within the element via the flow paths. This ensures, in particular, that the hydraulic fluid acts on the compensation body from all sides and that only individual sections of the compensation body are compressed excessively, thereby increasing the service life of the compensation body.

[0013] Advantageously, a particle foam can be used, with the spherical structure being formed by the shape of the individual particles. By using a particle foam, the shape of the individual particles naturally results in a spherical surface during the manufacturing of the leveling element, without requiring any special processing steps. Of course, the structure can be further enhanced during the molding process, for example, by using appropriately structured molds.

[0014] Preferably, the compensating element consists of an expanded thermoplastic elastomer, particularly preferably an expanded thermoplastic polyurethane. The individual particles can be fused together to form a molded part, thus creating the compensating element. Alternatively, the individual particles can also be arranged loosely within the compensating housing, thereby forming the compensating element. To withstand numerous compression and rebound cycles without damage, the compensating element must be highly elastic and securely contain the gas. If the pores were to rupture, the gas could escape, jeopardizing the operational reliability of the actuator. Common expanded polyethylene foams lose elasticity at low temperatures, which can lead to damage.Furthermore, expanded polyethylene foams are not suitable for continuous load-bearing capacity and possess very low resilience, making them fundamentally unsuitable for use in the present invention. While cellular rubber could theoretically be used with regard to the required material properties, its design limitations make it unsuitable. It has been shown that an expanded thermoplastic elastomer, such as, particularly advantageously, an expanded thermoplastic polyurethane, does not exhibit these disadvantages. Expanded thermoplastic polyurethane possesses high elasticity and load-bearing capacity, thus enabling the compensating element to permanently compensate for slowly occurring volume changes.Furthermore, expanded thermoplastic polyurethane possesses a high restoring force, which means that, regardless of its orientation, the hydraulic fluid contained within the volume compensation element is reliably forced out of the element when the temperature decreases. This is particularly advantageous for mounting the drive in various positions. The low density of expanded thermoplastic polyurethane allows for high compression of the compensation element, enabling it to compensate for large volume changes in the hydraulic fluid. In addition, expanded thermoplastic polyurethane exhibits high chemical resistance to common hydraulic fluids, especially oil, thus increasing the service life of the compensation element.In the event of a fire, the compensating element is initially compressed due to the heating of the hydraulic fluid. Since an expanded thermoplastic elastomer is advantageously used, the compensating element melts at high temperatures, thereby eliminating its restoring force. This prevents the hydraulic fluid from being forced out of the drive by the restoring force of the compensating element in the event of a failure, particularly a melting, of a seal in the drive. Furthermore, melting the compensating element releases an even larger volume for the hydraulic fluid compared to complete compression, thus also preventing bursting due to excessive pressure within the drive.

[0015] Advantageously, the compensating element has a defined melting point, which is in particular not more than 600°C, in particular not more than 500°C, in particular not more than 300°C, in particular not more than 260°C, and / or at least 100°C, in particular at least 120°C, in particular at least 140°C. The defined melting point enables – especially with regard to volume compensation – reliable operation of the drive within the respective climatic conditions, whereby the compensating element melts reliably in the event of a fire. The aforementioned values ​​have proven to be particularly suitable.

[0016] Preferably, the amount of hydraulic fluid is dimensioned such that, at a fluid temperature corresponding to a predefined temperature, in particular 20°C, the compensating element is partially compressed by the hydraulic fluid. This causes the hydraulic fluid to flow out of the compensating element as it cools below the predefined temperature, expanding the compensating element. For example, during the manufacture of the actuator, an increased quantity of hydraulic fluid, or hydraulic fluid cooled below the predefined temperature (which expands upon heating), can be incorporated into the actuator housing, so that the compensating element is partially compressed, i.e., pre-stressed, at a fluid temperature corresponding to the predefined temperature.If the temperature drops below the predefined temperature, the volume of the hydraulic fluid decreases. As the compensating element expands, the hydraulic fluid can flow out of the volume compensation element without creating a vacuum in the actuator. If a vacuum were to occur in the actuator, dissolved gases in the hydraulic fluid could be released, potentially disrupting or even causing the hydraulic damping function to fail. The advantageous preload of the compensating element prevents this, thus ensuring particularly reliable operation of the actuator over a wide temperature range, especially at low temperatures. Naturally, it is advantageous if the predefined temperature corresponds, for example, to the typical room temperature at the actuator's operating location.

[0017] Regarding the flow-dependent check valve, it is preferably provided that the flow-dependent check valve comprises a sealing point and a locking element by means of which the sealing point can be sealed. A pressure force dependent on the back pressure acts on the locking element, and the locking element is subjected to a counterforce opposing the pressure force such that, if the back pressure is below the predetermined value, the locking element does not seal the sealing point, thus preventing the flow-dependent check valve from closing the outlet. Conversely, if the back pressure is above the predetermined value, the locking element seals the sealing point, thus preventing the flow-dependent check valve from closing the outlet. If the back pressure again falls below the predetermined value—for example, after the wing has ceased moving—the counterforce prevents the locking element from sealing the sealing point.This allows for a particularly simple technical implementation of the flow-dependent check valve's functionality. The counterforce ensures that the sealing element does not close the sealing point when the back pressure is below the specified value.

[0018] The locking element can be designed as a geometric body, in particular a sphere or a cone, which can be displaced from a rest position (in which the geometric body does not seal the sealing point) by the back pressure. A separately designed return spring can be provided, which acts on the geometric body, with the spring force of the return spring providing the counterforce. The return spring ensures that the flow-dependent check valve is in a controlled open state in every position of the actuator – provided the back pressure is below the specified value – thereby increasing the operational reliability of the actuator. However, the flow-dependent check valve could also be designed without the return spring, in which case the counterforce could be provided, for example, primarily by the weight force acting on the locking element.

[0019] Furthermore, the closure element can have a first chamber containing the geometric body, a second chamber into which the outlet opens and in which the return spring is located, and a tapered section through which the first chamber narrows towards the second chamber. This arrangement allows for a particularly simple and robust design of the flow-dependent check valve. It goes without saying that the geometric body does not have to be entirely within the first chamber, nor does the return spring have to be entirely within the second chamber, but, depending on the position of the geometric body, may also extend into the tapered section and / or into the second and / or first chamber.

[0020] Furthermore, it can be provided that the sealing point, in particular as a circular sealing edge, is formed at the tapered section and that the geometric body is received in the first chamber in such a way that the geometric body is spaced away from the sealing point in its rest position, whereby the geometric body is moved into an end position when the dynamic pressure exceeds the specified value, in which the geometric body seals the sealing point. This ensures particularly reliable operation.

[0021] The locking element can alternatively or additionally be designed as an elongated, particularly tongue-shaped, elastically bendable flat part, especially made of spring steel or elastic plastic, which, from a resting state in which the flat part does not seal the sealing point, can be elastically bent by the back pressure, with the restoring force of the flat part providing the counterforce. This results in a particularly simple and durable design of the flow-dependent check valve.

[0022] It can be provided that the sealing surface surrounds the outflow opening completely, in particular as an annular projection, and that the flat part is attached to the closure element with a first section such that a second section of the flat part is spaced away from the sealing surface in its resting state. When the back pressure exceeds the specified value, the flat part bends into a final position such that the second section seals the sealing surface. Since the flow-dependent check valve has a flat sealing surface and not merely a sealing edge, this design is particularly robust and wear-resistant.

[0023] Furthermore, the locking element can alternatively or additionally be designed as a sensor with a sliding section, wherein the sliding section is inserted into the outflow opening and guided axially within it, thus allowing the sensor to be axially displaceable on the closure element. This allows for a particularly simple manufacture of the flow-dependent check valve.

[0024] Advantageously, elastic spring arms, whose free ends rest against the sealing element, are formed on the sensor. From a rest position, in which the sensor does not seal the sealing point, the sensor can be displaced by the back pressure, causing the spring arms to bend. The restoring force of the spring arms provides the counterforce. This results in a particularly simple and durable design for the flow-dependent check valve.

[0025] Furthermore, the sensor may be designed to have an elastic sealing element, in particular an O-ring, whereby, at a back pressure exceeding a predetermined value, the sensor is moved into an end position in which the elastic sealing element rests flat against the closure element, thus sealing the sealing point. The contact surface of the closure element, against which the elastic sealing element rests, forms the sealing point. Since the flow-dependent check valve has a flat sealing area and not merely a sealing edge, this design is particularly robust and wear-resistant. Additionally, contamination in the sealing area can be covered by the elastic sealing element, thus maintaining the sealing function even if the sealing point is contaminated.

[0026] Preferably, a gas separator element is provided in the compensating housing between the closure element and the compensating body. This element completely covers the outflow opening or is inserted into the outflow opening, consists of a porous material or wire mesh, and is wetted by the hydraulic fluid. The gas separator element has a predetermined bubble breakthrough pressure. This bubble breakthrough pressure is predetermined such that any gas within the volumetric compensating element, which may be released, for example, by the rupture of a cavity in the compensating body after numerous compression and rebound cycles during operation, cannot exceed the predetermined bubble breakthrough pressure. This prevents the gas from penetrating the gas separator element and thus from flowing out of the volumetric compensating element.Consequently, the gas separator element represents a particularly simple solution without the need for any additional components and / or structures to prevent free gas from interfering with the hydraulic functions of the drive, thereby increasing the reliability of the drive.

[0027] It is particularly preferred that the gas separation element is disc-shaped and / or consists of a sintered material, in particular sintered spheres, and / or of a braided core. Such a gas separation element can be manufactured particularly easily and fitted into the volume compensation element.

[0028] Furthermore, the drive is advantageously designed such that the drive mechanism comprises an output shaft rotatably mounted about a pivot axis, a linearly displaceable piston coupled to the output shaft which rotates the output shaft upon displacement, and a compression spring with a first end and a second end, the first end of which rests against the piston and exerts a compression spring force on it. In particular, the drive mechanism additionally comprises a spindle with a spindle plate against which the second end of the compression spring rests and via which the compression spring force can be adjusted. The volume compensation element is arranged in a space enclosed by the compression spring and / or within the spindle and / or is at least partially formed by the spindle. This enables a particularly simple and compact design of the drive.

[0029] The invention is described below by way of example with reference to the figures. The figures show schematically Fig. 1 shows a first embodiment of a drive according to the invention with a volume compensation element with a compensation body, Fig. 2 shows the volume compensation element of the Fig. 1 in an uncompressed and a compressed state of the compensating body, Fig. 3 a compensating body with channel-like recesses, Fig. 4 a compensating housing and a closing element, each with internal recesses, Fig. 5 a compensating body with a spherically structured surface, Fig. 6 a volume compensating element with a compensating body prestressed at a predefined temperature, Fig. 7 a detail view of a flow-dependent check valve with a return spring and a ball in a rest position and an end position, Fig. 8 a detail view of an exemplary alternative arrangement of the flow-dependent check valve of the Fig. 7 Fig. 9 shows a detailed view of a flow-dependent check valve with an elongated flat part in a rest state and a final state; Fig. 10 shows a perspective detail view of the flow-dependent check valve. Fig. 9 Fig. 11 a detailed view of a flow-dependent check valve with a sensor in a rest position and an end position, Fig. 12 a perspective detailed view of the flow-dependent check valve of the Fig. 11 Fig. 13 shows a volume compensation element with a gas separation element, Fig. 14 shows a perspective detail view of the volume compensation element of the Fig. 13 .

[0030] Fig. 1 Figure 1 shows a first embodiment of a drive 11 according to the invention, comprising a drive mechanism 13 arranged at least partially in a drive housing 15 and a volume compensation element 19. The drive mechanism 13 includes an output shaft 77 rotatably mounted about a pivot axis, a linearly displaceable piston 79 coupled to the output shaft 77, which rotates the output shaft 77 when displaced, and a compression spring 81. The compression spring 81 has a first end 83 and a second end 85, wherein the first end 83 of the compression spring 81 bears against the piston 79 and exerts a compression spring force on it. Additionally, a spindle 87 with a spindle plate 89 is provided, against which the second end 85 of the compression spring 81 bears and via which spindle 87 the compression spring force can be adjusted.When the drive 13 is coupled to a wing, a rotary movement of the output shaft 77 is accompanied by a movement of the wing. To achieve a defined damping characteristic, a hydraulic fluid 17 in the form of oil is contained within the drive housing 15. A chamber 91 is enclosed by the compression spring 81. This chamber 91 is also filled with the oil 17, and the volume compensation element 19 is located within it. The volume compensation element 19 compensates for volume changes of the oil 17 due to temperature variations, particularly those caused by climatic conditions, thereby maintaining a constant pressure within the drive 11.

[0031] Fig. 2 The volume compensation element 19 shows the Fig. 1 in two different states. The volume compensation element 19 comprises an elastically compressible compensating body 21, which consists of a closed-cell foam, in particular particle foam. For this purpose, expanded thermoplastic polyurethane particles were fused to form the compensating body 21, which has a defined melting point of, for example, 200°C. The volume compensation element 19 also comprises a compensating housing 23 with a housing opening into which the compensating body 21 is inserted, and a closing element 25, which closes the housing opening and is provided with an exhaust opening 27.

[0032] The upper representation in Fig. 2 Figure 1 shows the volume compensation element 19 in a state in which the compensating body 21 is not compressed and fills the interior of the volume compensation element 19. With an increase in the temperature of the oil 17, its volume increases, with the oil 17 flowing into the volume compensation element 19 via the outflow opening 27 and compressing the compensating body 21. The lower illustration in Fig. 2 Figure 1 shows the volume compensation element 19 in a state where the compensating body 21 is compressed. The additional volume provided within the volume compensation element 19 by the compression of the compensating body 21 serves to compensate for the volume increase of the oil 17, thus maintaining a constant pressure in the actuator 11. If the temperature of the oil 17 decreases, the oil 17 flows out of the volume compensation element 19 as the compensating body 21 expands, with the restoring force of the compensating body 21 forcing the oil 17 out of the volume compensation element 19. The use of expanded thermoplastic polyurethane makes this displacement particularly reliable, as expanded thermoplastic polyurethane exhibits a high restoring force.Furthermore, the expanded thermoplastic polyurethane exhibits high elasticity and durability as well as high chemical resistance to the oil 17, thus enabling a long service life of the compensating body 21.

[0033] In the event of a fire, the compensating element 21 melts according to the defined melting temperature, thereby eliminating the restoring force of the compensating element 21 and releasing additional volume for the oil 17. This prevents the drive 11 from bursting in the event of a failure, particularly a melting, of a seal of the drive 11.

[0034] In addition to the temperature-related volume changes of the oil 17 described above, increased pressures occur within the drive 11 during operation due to the movement of the piston 79 and the associated movement of the oil 17. These operational pressures typically exhibit a high pressure rise within a short time and a high absolute value. However, they do not pose a danger to the drive mechanism 13 or the drive housing 15; rather, they are necessary for a defined damping behavior and are closely interrelated with it. Therefore, in order to prevent the damping behavior from being disrupted by compression of the compensating element 21, and to protect the compensating element 21 from operationally increased pressures, the sealing element 25 also incorporates a flow-dependent check valve 29.This closes the outlet opening 27 when the back pressure of the oil 17 occurring outside the volume compensation element 19 exceeds a predetermined value, preventing oil 17 from flowing into the volume compensation element 19. The predetermined value depends on the operating pressures, particularly the back pressures occurring at the flow-dependent check valve 29 during operation. The back pressure is primarily dependent on the flow velocity of the hydraulic fluid. The operation of the flow-dependent check valve 29 is described in the following. Fig. 7 und 8 described, which each show a slightly modified flow-dependent check valve 29, whereby the operating principle is nevertheless the same and refer to the closure element 25 and the flow-dependent check valve 29 according to Fig. 1 can be transferred.

[0035] In Fig. 3 Another compensating body 21 of a different embodiment of a drive 11 according to the invention is shown, wherein the compensating body 21 has several channel-like recesses 31, which are formed on its surface in both the axial and radial directions of the compensating body 21. Several flow paths for the hydraulic fluid 17 are formed within the volume compensation element 19 via the recesses 31 of the compensating body 21. The hydraulic fluid 17 can reliably flow to the outlet opening 27 of the closure element 25 via these flow paths, one of which is illustrated by an arrow. This prevents the compensating body 21 from closing the outlet opening 27 in certain positions of the drive 11 or the hydraulic fluid 17 from being trapped in the volume compensation element 19, which would impair the function of the volume compensation element 19.Furthermore, hydraulic fluid 17 flowing into the volume compensation element 19 can reliably distribute itself within the volume compensation element 19 via the flow paths. This ensures, in particular, that the hydraulic fluid 17 acts on the compensation body 21 from all sides, thereby increasing the service life of the compensation body 21.

[0036] Fig. 4 Figure 1 shows a sectional view of a volume compensation element 19 of a further embodiment of a drive 11 according to the invention with a compensation housing 23 and a closure element 25, wherein several channel-like recesses 31 are formed on the inner wall, analogous to those in Figure 2. Fig. 2 The recesses 31 of the compensating body 21 shown form flow paths. For clarity, other components of the volume compensating element 19, except for the outflow opening 27, are shown in Fig. 4 not shown.

[0037] Another possibility for the formation of flow paths is in Fig. 5 Figure 21 shows a compensating body 21 with a spherically structured surface. The compensating body 21 consists of an expanded particle foam, with the spherical structure 35 being formed by the shape of the individual particles of the particle foam. This allows for the simple creation of a variety of flow paths, one of which is illustrated by the arrow.

[0038] At a Fig. 6 In the illustrated volume compensation element 19 of a further embodiment of a drive 11 according to the invention, it is provided that a compensating element 21 is already partially compressed at a predefined temperature of 20°C. For this purpose, during the manufacture of the drive 11, the hydraulic fluid 17 with a fluid temperature of, for example, 10°C was included in the drive housing 15. When heated to the predefined temperature of 20°C, the hydraulic fluid 17 expanded such that the compensating element 21 was partially compressed or pre-tensioned. If the temperature of the hydraulic fluid 17 decreases below the predefined temperature of 20°C, the volume of the hydraulic fluid 17 decreases accordingly, whereby the hydraulic fluid 17 can flow out of the volume compensation element 19 as the compensating element 21 expands, without creating a vacuum in the drive 11.If a vacuum were to occur in the actuator 11, dissolved gases in the hydraulic fluid 17 could be released, disrupting or even causing the hydraulic damping functions to fail. The advantageous preload of the compensating element 21 prevents this, thus ensuring particularly reliable operation of the actuator 11 over a wide temperature range, especially at low temperatures.

[0039] Fig. 7 Figure 1 shows a detailed view of a closure element 25 with a flow-dependent check valve 29 of a further embodiment of an actuator 11 according to the invention. The closure element 25 has a first chamber 65, a second chamber 67 into which an outlet opening 27 opens, and a tapered section 69, via which the first chamber 65 tapers towards the second chamber 67. A geometric body 47 in the form of a sphere 47a is accommodated within the first chamber 65 and is acted upon by a return spring 63 located in the second chamber 67. Furthermore, a circular sealing edge 39 is formed on the tapered section 69, which can be sealed by the sphere 47a.

[0040] The left-hand representation in Fig. 7 Figure 1 shows the flow-dependent check valve 29 in an open position, in which the flow-dependent check valve 29 does not close the outlet opening 27. The ball 47a is in a rest position, in which the ball 47a is spaced from the sealing edge 39 and does not seal the sealing edge 39. The hydraulic fluid 17 can thus flow past the ball 47a and through the outlet opening 27 into the volume compensation element 19. A back pressure builds up on the ball 47a, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to the back pressure, a pressure force acts on the ball 47a, which attempts to displace the ball 47a towards the sealing edge 39. Conversely, the ball 47a is subjected to a counterforce provided by the spring force of the return spring 63.If the compressive force exceeds the spring force of the return spring 63, the ball 47a can be displaced from its rest position, compressing the return spring 63.

[0041] If the dynamic pressure exceeds the specified value, the pressure force is so high compared to the spring force of the return spring 63 that the ball 47a is moved into an end position, which is shown in the right-hand illustration. Fig. 7 As shown, the ball 47a seals the sealing edge 39, causing the flow-dependent check valve 29 to close the outlet 27. When the pressure force falls below the spring force of the return spring 63, the ball 47a can be moved back by the spring force of the return spring 63. The ball 47a is then again spaced away from the sealing edge 39, preventing the flow-dependent check valve 29 from closing the outlet 27. The specified value is defined, and in particular the return spring 63 is dimensioned according to this specified value, such that operational back pressures move the ball 47a into its end position, but back pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

[0042] In Fig. 8 Figure 1 shows a detailed view of a closure element 25 with a flow-dependent check valve 29 of another embodiment of an actuator 11 according to the invention, which has a function that corresponds to the one described above. Fig. 7 The described analogous element is also present. The locking element 25 is also present. Fig. 8 in particular it has a first chamber 65, a second chamber 67 and a tapering section 69, above which the first chamber 65 tapers to the second chamber 67, wherein the outflow opening 27 opens into the second chamber 67 transversely to the direction of the tapering.

[0043] Fig. 9 Figure 1 shows a detailed view of a closure element 25 with an alternative flow-dependent check valve 29 of a further embodiment of an actuator 11 according to the invention. The closure element 25 has a tongue-shaped, elastically bendable flat part 49 made of spring steel, which is attached to the closure element 25 by a first section 51. In addition, a sealing point 37 in the form of an annular projection 41 surrounding the outflow opening 27 is provided on the closure element 25, which can be sealed by a second section 53 of the flat part 49.

[0044] The left-hand representation in Fig. 9 Figure 1 shows the flow-dependent check valve 29 in an open state, in which the flow-dependent check valve 29 does not close the outlet opening 27. The flat part 49 is in a resting state, in which the second section 53 is spaced apart from the projection 41 and does not seal the projection 41. Accordingly, the hydraulic fluid 17 can flow past the flat part 49 and through the outlet opening 27 into the volume compensation element 19. A back pressure builds up on the flat part 49, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to the back pressure, a pressure force acts on the flat part 49, which attempts to bend the flat part 49, especially with the second section 53, towards the projection 41. In contrast, the flat part 49 is subjected to a counterforce provided by the restoring force of the flat part 49.If the compressive force exceeds the restoring force of the flat part 49, the flat part 49 can be elastically bent from its resting state.

[0045] If the dynamic pressure exceeds the specified value, the compressive force is so high compared to the restoring force of the flat part 49 that the flat part 49 is bent into a final state, which is shown in the right-hand illustration. Fig. 9 As shown, the second section 53 seals the projection 41, causing the flow-dependent check valve 29 to close the outlet 27. If the pressure force decreases below the restoring force of the flat part 49, the flat part 49 can return to its original position, so that the second section 53 is spaced away from the projection 41, preventing the flow-dependent check valve 29 from closing the outlet 27. The specified value is defined, and in particular the flat part 49 is dimensioned according to this specified value, such that operational back pressures bend the flat part 49 into its final state, but back pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

[0046] Fig. 10 This shows in Fig. 9 The illustrated closure element 25 with the flow-dependent check valve 29 is shown in a perspective detail view, in which in particular the projection 41 as well as the tongue-shaped design and the attachment of the flat part 49 to the closure element 25 are shown.

[0047] Fig. 11 Figure 1 shows a detailed view of a closure element 25 with an alternative flow-dependent check valve 29 of a further embodiment of an actuator 11 according to the invention. The closure element 25 has an outlet opening 27 and a receiver 55 with a sliding section 57, wherein the sliding section 57 is inserted into the outlet opening 27 and guided axially displaceably within it. Consequently, the receiver 55 is also arranged axially displaceably on the closure element 25. Furthermore, locking lugs (not specified in detail) are formed on the sliding section 57 to prevent unintentional slippage of the sliding section 57 out of the outlet opening 27. In addition, two elastic spring arms 59 are formed on the receiver 55, the free ends 61 of which each bear against the closure element 25.Furthermore, the receiver 55 has an elastic sealing element 71 in the form of an O-ring and the closure element 25 has a contact surface 43 provided for the sealing element 71, which can be sealed by the sealing element 71.

[0048] The left-hand representation in Fig. 11 Figure 1 shows the flow-dependent check valve 29 in an open position, in which the flow-dependent check valve 29 does not close the outlet opening 27. The sensor 55 is in a rest position, in which the sealing element 71 is spaced away from the contact surface 43 and does not seal the contact surface 43. Accordingly, the hydraulic fluid 17 can flow past the sealing element 71 and through the outlet opening 27 into the volume compensation element 19. A back pressure builds up on the sensor 55, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to the back pressure, a pressure force acts on the sensor 55, which attempts to move the sensor 55 with the sealing element 71 towards the contact surface 43, thereby bending the spring arms 59. In contrast, the receiver 55 is subjected to a counterforce provided by the restoring force of the spring arms 59.If the compressive force exceeds the restoring force of the spring arms 59, the receiver 55 can be moved from its rest position.

[0049] If the dynamic pressure exceeds the specified value, the pressure force is so high compared to the restoring force of the spring arms 59 that the sensor 55 is moved into an end position, which is shown in the right-hand illustration of the Fig. 11 As shown, the sealing element 71 seals the contact surface 43, causing the flow-dependent check valve 29 to close the outlet opening 27. If the pressure force decreases below the restoring force of the spring arms 59, the sensor 55 can be moved back by the restoring force of the spring arms 59, so that the sealing element 71 is spaced away from the contact surface 43, thus preventing the flow-dependent check valve 29 from closing the outlet opening 27. The specified value is predetermined, and in particular, the spring arms 59 are dimensioned according to this predetermined value such that operational back pressures move the sensor 55 into its end position, but back pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

[0050] Fig. 12 This shows in Fig. 11 The illustrated closure element 25 with the flow-dependent check valve 29 is shown in a perspective detail view, in which in particular the sensor 55 with the sealing element 71 and the design of the spring arms 59 are shown.

[0051] In Fig. 13 A volume compensation element 19 of a further embodiment of a drive 11 according to the invention is shown. This volume compensation element 19 essentially corresponds to that described in the Fig. 1 und 2 embodiment shown, wherein in Fig. 13 In the volume compensation element 19 shown, a disc-shaped gas separator element 75 is arranged between the closure element 25 and the compensation body 21. This gas separator element completely covers the outflow opening 27, preventing any hydraulic fluid 17 or gas from passing through the circumferential surface between the gas separator element 75 and the closure element 25. The gas separator element 75 consists of a porous sintered material and is wetted by the hydraulic fluid 17, giving the gas separator element 75 a predetermined bubble breakthrough pressure. This bubble breakthrough pressure is predetermined such that any gas contained within the volume compensation element 19, which may be released, for example, by the rupture of a cavity in the compensation body 21 after numerous compression and rebound cycles during operation, cannot exceed the predetermined bubble breakthrough pressure.This prevents the gas from passing through the gas separator element 75 and thus from flowing out of the volume compensation element 19.

[0052] Fig. 14 This shows in Fig. 13 The volume compensation element 19 is shown in a perspective detail view, in which the disc-shaped gas separation element 75 is shown in particular. As the Fig. 13 und 14 As can be seen, the gas separator element 75 represents a particularly simple solution without the need for any additional components and / or constructions to prevent free gas from interfering with the hydraulic functions of the drive 11. Bezugszeichenliste

[0053] 11 Actuator 13 Actuator mechanism 15 Actuator housing 17 Hydraulic fluid 19 Volume compensating element 21 Compensating body 23 Compensating housing 25 Closing element 27 Outlet opening 29 Flow-dependent check valve 31 Recess 35 Structure 37 Sealing point 39 Sealing edge 41 Projection 43 Contact surface 47 Geometric body 47a Ball 49 Flat part 51 First section 53 Second section 55 Sensor 57 Sliding section 59 Spring arm 61 Free end 63 Return spring 65 First chamber 67 Second chamber 69 Tapered section 71 Sealing element 75 Gas separator element 77 Output shaft 79 Piston 81 Compression spring 83 First end 85 Second end 87 Spindle 89 Spindle plate Room 91

Claims

1. A drive (11) for a sash of a window or door, in particular a door closer, comprising a drive mechanism (13) for moving the sash, a drive housing (15) in which the drive mechanism (13) is at least partially arranged, a hydraulic fluid (17), in particular oil, which is accommodated in the drive housing (15), and a volume compensation element (19) arranged within the drive housing (15), wherein the volume compensation element (19) comprises an elastically compressible compensation body (21) consisting of a closed-cell foam, in particular particle foam, a compensation housing (23) with a housing opening into which the compensation body (21) is inserted, and a closure element (25) closing the housing opening, wherein the closure element (25) has an outflow opening (27),via which the hydraulic fluid (17) flows into the volume compensation element (19) upon an increase in the fluid temperature, compressing the compensation body (21), and out of the volume compensation element (19) upon a decrease in the fluid temperature, expanding the compensation body (21), and wherein the closure element (25) has a flow-dependent check valve (29) which closes the outflow opening (27) when a back pressure of the hydraulic fluid (17) occurring outside the volume compensation element (19) is above a predetermined value, so that no hydraulic fluid (17) can flow into the volume compensation element (19).

2. Drive (11) according to claim 1, characterized by thatthe compensating body (21) has on its surface and / or the compensating housing (23) on its inner wall and / or the closure element (25) one or more, in particular channel-like, depressions (31) and / or elevations and / or a, in particular spherical, structuring (35), whereby one or more flow paths for the hydraulic fluid (17) are formed within the volume compensating element (19); optionally wherein the spherical structuring (35) is formed by the particles of the particle foam.

3. Drive (11) according to one of the preceding claims, characterized by that the compensating body (21) consists of an expanded thermoplastic elastomer, preferably of an expanded thermoplastic polyurethane.

4. Drive (11) according to one of the preceding claims, characterized by thatthe compensating body (21) has a defined melting temperature which is in particular at most 600°C, in particular at most 500°C, in particular at most 300°C, in particular at most 260°C, and / or at least 100°C, in particular at least 120°C, in particular at least 140°C.

5. Drive (11) according to one of the preceding claims, characterized by that the amount of the hydraulic fluid (17) is dimensioned such that at a fluid temperature which corresponds to a predefined temperature, in particular of 20°C, the compensating body (21) is partially compressed by the hydraulic fluid (17), whereby the hydraulic fluid (17) flows out of the volume compensation element (19) upon cooling below the predefined temperature, with expansion of the compensating body (21).

6. Drive (11) according to one of the preceding claims, characterized by thatthe flow-dependent check valve (29) comprises a sealing point (37) and a blocking element (47; 49; 55) by means of which the sealing point (37) can be sealed, wherein a compressive force dependent on the dynamic pressure acts on the blocking element (47; 49; 55) and the blocking element (47; 49; 55) is subjected to a counterforce opposing the compressive force such that, if the dynamic pressure is below the predetermined value, the blocking element (47; 49; 55) does not seal the sealing point (37), whereby the flow-dependent check valve (29) does not close the outflow opening (27), or, if the dynamic pressure is above the predetermined value, the blocking element (47; 49; 55) seals the sealing point (37), whereby the flow-dependent check valve (29) closes the outflow opening (27) closes.

7. Drive (11) according to claim 6, characterized by thatthe blocking element is designed as a geometric body (47), in particular as a sphere (47a) or a cone, which can be displaced by the dynamic pressure from a rest position in which the geometric body (47) does not seal the sealing point (37), and a separately designed return spring (63) is provided which acts on the geometric body (47), the spring force of the return spring (63) providing the counterforce.

8. Drive (11) according to claim 7, characterized by that the closure element (25) has a first chamber (65) in which the geometric body (47) is accommodated, a second chamber (67) into which the outflow opening (27) opens and in which the return spring (63) is arranged, and a tapered section (69) via which the first chamber (65) tapers towards the second chamber (67).

9. Drive (11) according to claim 8, characterized by thatthe sealing point (37), in particular as a circular sealing edge (39), is formed on the tapered section (69), and the geometric body (47) is accommodated in the first chamber (65) in such a way that the geometric body (47) is spaced apart from the sealing point (37) in the rest position, wherein the geometric body (47) is displaced into an end position in the case of a dynamic pressure above the predetermined value, in which end position the geometric body (47) seals the sealing point (37).

10. Drive (11) according to claim 6, characterized by thatthe blocking element is designed as an elongated, in particular tongue-shaped, elastically bendable flat part (49), in particular consisting of spring sheet or elastic plastic, which can be elastically bent by the dynamic pressure from a rest state in which the flat part (49) does not seal the sealing point (37), wherein the restoring force of the flat part (49) provides the counterforce; optionally wherein the sealing point (37) surrounds the outflow opening (27) in a planar manner, in particular is designed as an annular projection (41), and the flat part (49) is fastened by a first section (51) to the closure element (25) in such a way that a second section (53) of the flat part (49) is spaced from the sealing point (37) in the rest state, wherein the flat part (49) is bent into a final state when the dynamic pressure exceeds the predetermined value such that the second section seals the sealing point (37).

11. Drive (11) according to claim 6, characterized by that the blocking element is designed as a receiver (55) with a sliding section (57), wherein the sliding section (57) is inserted into the outflow opening (27) and is guided axially displaceably therein, whereby the receiver (55) is arranged axially displaceably on the closure element (25).

12. Drive (11) according to claim 11, characterized by that elastic spring arms (59), the free ends (61) of which rest on the closure element (25), are formed on the receiver (55), which can be displaced by the dynamic pressure from a rest position in which the receiver (55) does not seal the sealing point (37), whereby the spring arms (59) are bent, wherein the restoring force of the spring arms (59) provides the counterforce; and / or thatthe receiver (55) has an elastic sealing element (71), in particular an O-ring, wherein the receiver (55) is displaced into an end position when the dynamic pressure exceeds the predetermined value, in which end position the elastic sealing element (71) lies flat against the closure element (25), whereby the receiver (55) seals the sealing point (37), wherein the support surface (43) of the closure element, on which the elastic sealing element (71) rests for sealing, forms the sealing point (37).

13. Drive (11) according to one of the preceding claims, characterized by that in the compensation housing (23) between the closure element (25) and the compensation body (21) a gas separation element (75) is provided, which completely covers the outflow opening (27) or is inserted into the outflow opening (27), consists of a porous material or a wire mesh and is wetted by the hydraulic fluid (17).

14. Drive (11) according to claim 13, characterized by that the gas separation element (75) is disc-shaped and / or consists of a sintered material, in particular sintered spheres, and / or a twill braid.

15. Drive (11) according to one of the preceding claims, characterized by thatthe drive mechanism (13) comprises an output shaft (77) mounted so as to be rotatable about an axis of rotation, a linearly displaceable piston (79) which is coupled to the output shaft (77) and rotates the output shaft (77) when displaced, and a compression spring (81) having a first end (83) and a second end (85), which is supported with its first end (83) on the piston (79) and applies a compression spring force to the piston, in particular wherein the drive mechanism (13) additionally comprises a spindle (87) with a spindle plate (89), on which the second end (85) of the compression spring (81) is supported and via which spindle (87) the compression spring force can be adjusted, wherein the volume compensation element (19) is arranged in a space (91) wrapped around the compression spring (81) and / or within the spindle (87) and / or is formed at least partially by the spindle (87).