Drive for a sash of a window or 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 wing of a window or a door, in particular a door closer, comprising a drive mechanism for moving the wing, a drive housing in which the drive mechanism is at least partially arranged, and a hydraulic fluid, in particular oil, which is accommodated in the drive housing.

[0002] The drive mechanism typically comprises an output shaft mounted for rotation about a rotation axis, a linearly displaceable piston coupled to the output shaft and rotating the output shaft upon displacement, and a compression spring having a first end and a second end, which is supported with its first end on the piston and applies a compression spring force thereto.

[0003] Drives for moving a window or door sash, especially door closers, are typically filled with a hydraulic fluid (usually oil) to achieve a defined damping behavior of the drive. When the hydraulic fluid heats up, for example due to climatic conditions or a fire, it tends to expand accordingly. Since the hydraulic fluid is incompressible, heating the hydraulic fluid leads to an increase in pressure within the drive. If the pressure is too high, the drive seals can fail, and the hydraulic fluid can leak out. Furthermore, excessive pressure could also cause the drive to burst.

[0004] In order to prevent a pressure increase, it is known to keep a small amount of air in the drive. This can be compressed when the hydraulic fluid expands without the pressure in the drive increasing unacceptably. In such drives, the air volume can compensate for changes in the volume of the hydraulic fluid that accompany temperature fluctuations of up to, for example, 70°C. A disadvantage, however, is that the air disrupts the hydraulic functions of the drive: Since the air is compressed first before throttle pressure can build up, damping functions sometimes start with a delay. This ultimately poses a risk to the functional reliability of the drive. Furthermore, such drives can no longer effectively compensate for changes in the volume of the hydraulic fluid that occur in the event of a fire with significantly higher temperatures, thus creating the risk of seal failure or even the drive bursting.

[0005] The invention is therefore based on the object 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 increase unduly over a large temperature range, whereby the damping behavior is not disturbed.

[0006] This object is achieved by a drive having the features of claim 1, and in particular in 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 upon an increase in the fluid temperature, compressing the compensation body, and flows out of the volume compensation element upon a decrease in the fluid temperature, expanding the compensation 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 is above a predetermined value, so that no hydraulic fluid can flow into the volume compensation element.

[0007] As hydraulic fluid flows into the volume compensation element, the compensation body is compressed. This releases additional volume for the hydraulic fluid, preventing pressure in the drive from increasing. Because the compensation body is made of closed-cell foam, it cannot absorb hydraulic fluid, which would otherwise result in a loss of compressibility. Rather, the elastic closed-cell foam can be compressed particularly easily due to the gas trapped in its cavities. If the compensation body is damaged—for example, a cavity could rupture after numerous compression and recovery processes over the course of its service life—only a very small amount of gas can escape, which essentially corresponds to a negligible proportion of the total gas trapped in the compensation body.Consequently, the hydraulic function is not significantly affected despite damage to the compensating body, thus increasing the reliability of the drive. A drive that, for example, only uses an elastic balloon filled with a gas for volume compensation would not offer this advantage, as damage to the balloon would cause all of the gas to escape.

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

[0009] In principle, the back pressure depends particularly on the flow velocity of the hydraulic fluid, with higher flow velocities occurring during drive operation due to piston movement than due to temperature-related volume changes in the hydraulic fluid. Since the flow-dependent check valve closes the discharge opening when the back pressure of the hydraulic fluid outside the volume compensation element exceeds the specified value, which is determined in particular by the back pressures occurring during drive operation, sudden pressure increases, such as those that can occur when the vane moves in the drive, cannot affect the compensation body.In contrast, slow, temperature-related volume changes in the hydraulic fluid generally generate insignificant back pressures below the specified value, at which the flow-dependent check valve does not close the discharge opening, 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 drive – despite the volume compensation functionality provided. Furthermore, the compensation body itself is also protected from high pressures, resulting in a particularly long service life of the drive.

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

[0011] Advantageous embodiments of the invention emerge from the subclaims, the description and the figures.

[0012] It can be provided that the compensating body on its surface and / or the compensating housing on its inner wall and / or the closure element has one or more, in particular channel-like, depressions and / or elevations and / or a, in particular spherical, structure, whereby one or more flow paths for the hydraulic fluid are formed within the volume compensation element. The hydraulic fluid can flow reliably to the outflow opening of the closure element via the flow paths. This prevents the compensating body from closing the outflow opening - for example, in certain positions of the drive - which would prevent the hydraulic fluid from flowing into the volume compensation element. This also prevents the hydraulic fluid from becoming trapped in the volume compensation element. Consequently, the provision of the flow paths increases the functional safety and reliability of the drive.Furthermore, hydraulic fluid flowing into the volume compensation element can be reliably distributed within the volume compensation element via the flow paths. This ensures that the hydraulic fluid acts on the compensation body from all sides, rather than just individual sections of the compensation body being subjected to above-average compression, thus increasing the service life of the compensation body.

[0013] Advantageously, a particle foam can be used as the foam, with the spherical structure being formed by the shape of the individual particles of the particle foam. By using a particle foam, a spherical surface is created during the production of the compensating body due to the shape of the individual particles, without the need for any special processing steps. Of course, the structuring can be enhanced during the shaping of the compensating body, for example, by using appropriately structured molds.

[0014] The compensating body is preferably made of an expanded thermoplastic elastomer, particularly preferably an expanded thermoplastic polyurethane. The individual particles can be fused into a molded part to form the compensating body. Alternatively, the individual particles can be loosely arranged in the compensating housing to form the compensating body. In order to withstand a multitude of compression and recovery processes without damage, the compensating body must be highly elastic and securely contain the gas. If the pores were to rupture, the gas could escape, jeopardizing the functional reliability of the drive. Common expanded polyethylene foams lose elasticity at low temperatures, which can cause damage.Furthermore, expanded polyethylene foams are not suitable for continuous loading and have very low resilience, making expanded polyethylene foams fundamentally unsuitable for use in the present invention. Given the required material properties, cellular rubber could also be used, but this is structurally limited in its shaping and is therefore unsuitable. It has been shown that an expanded thermoplastic elastomer, such as, particularly advantageously, an expanded thermoplastic polyurethane, does not have these disadvantages. Expanded thermoplastic polyurethane exhibits high elasticity and continuous load-bearing capacity, enabling the compensation body to permanently compensate for slowly occurring volume changes.In addition, expanded thermoplastic polyurethane possesses a high restoring force, which means that the hydraulic fluid contained in the volume compensation element is reliably forced out of the volume compensation element when the temperature drops, regardless of the position. This is particularly advantageous for mounting the drive in different positions. The low density of expanded thermoplastic polyurethane enables high compression of the compensation element, which can compensate for large volume changes in the hydraulic fluid. Furthermore, expanded thermoplastic polyurethane exhibits high chemical resistance to common hydraulic fluids, especially oil, which increases the service life of the compensation element.In the event of a fire, the compensating body is initially compressed due to the heating of the hydraulic fluid. Since an expanded thermoplastic elastomer is advantageously used, the compensating body melts at high temperatures, eliminating the compensating body's restoring force. This prevents the hydraulic fluid from being forced out of the drive by the compensating body's restoring force in the event of a failure, particularly melting, of a drive seal. Furthermore, the melting of the compensating body releases an even larger volume for the hydraulic fluid compared to complete compression of the compensating body, which also prevents bursting due to excessive pressure within the drive.

[0015] Advantageously, the compensating body 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. The defined melting temperature enables reliable operation of the drive within the respective climatic conditions—particularly with regard to volume compensation—with the compensating body reliably melting in the event of a fire. The aforementioned values ​​have proven particularly suitable.

[0016] Preferably, the amount of hydraulic fluid is such that, at a fluid temperature corresponding to a predefined temperature, in particular 20°C, the compensating body is partially compressed by the hydraulic fluid, whereby, upon cooling below the predefined temperature, the hydraulic fluid flows out of the volume compensation element, causing the compensating body to expand. For example, during the manufacture of the drive, an increased amount of hydraulic fluid or hydraulic fluid cooled below the predefined temperature, which expands upon heating, can be accommodated in the drive housing under pressure, so that the compensating body is partially compressed, i.e., prestressed, at a fluid temperature corresponding to the predefined temperature.If the temperature drops below the predefined temperature, the volume of the hydraulic fluid decreases, allowing the hydraulic fluid to flow out of the volume compensation element as the compensation body expands, without creating a vacuum in the drive. If, instead, a vacuum were to occur in the drive, gases dissolved in the hydraulic fluid could be released, which could disrupt or even cause the hydraulic damping functions to fail. The advantageous preload of the compensation body prevents this, ensuring particularly reliable function of the drive over a wide temperature range, especially at low temperatures. It is of course advantageous if the predefined temperature corresponds, for example, to the usual room temperature at the location where the drive is operated.

[0017] With regard to the flow-dependent check valve, it is preferably provided that the flow-dependent check valve comprises a sealing point and a blocking element by means of which the sealing point can be sealed, wherein a compressive force dependent on the dynamic pressure acts on the blocking element and the blocking element is subjected to a counterforce opposing the compressive force such that, if the dynamic pressure is below the predetermined value, the blocking element does not seal the sealing point, whereby the flow-dependent check valve does not close the outflow opening, or, if the dynamic pressure is above the predetermined value, the blocking element seals the sealing point, whereby the flow-dependent check valve closes the outflow opening. If the dynamic pressure is again below the predetermined value - for example, after a movement of the wing has ended - the counterforce causes the blocking element to not seal the sealing point.This allows for a particularly simple technical implementation of the flow-dependent check valve's functionality. The counterforce ensures that the blocking element does not seal the sealing point when the back pressure is below the specified value.

[0018] The blocking element can be designed as a geometric body, in particular as a sphere or a cone, which can be displaced by the dynamic pressure from a rest position in which the geometric body does not seal the sealing point. 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 any position of the actuator - provided the dynamic pressure is below the specified value - thereby increasing the functional reliability of the actuator. The flow-dependent check valve could also be designed without the return spring, whereby the counterforce could, for example, be provided primarily by the weight acting on the blocking element.

[0019] In addition, the closure element can have a first chamber in which the geometric body is accommodated, a second chamber into which the outflow opening opens and in which the return spring is arranged, and a tapered section via which the first chamber tapers towards the second chamber. This arrangement allows for a particularly simple and robust construction of the flow-dependent check valve. It goes without saying that the geometric body does not have to be located entirely in the first chamber and the return spring does not have to be located entirely in the second chamber, but can also protrude into the tapered section and / or into the second and / or first chamber, particularly depending on the position of the geometric body.

[0020] Furthermore, it can be provided that the sealing point is formed on the tapered section, in particular as a circular sealing edge, and that the geometric body is accommodated in the first chamber in such a way that the geometric body is spaced from the sealing point in the rest position. When the dynamic pressure exceeds the predetermined value, the geometric body is displaced into an end position in which the geometric body seals the sealing point. This ensures particularly reliable operation.

[0021] The blocking element can alternatively or additionally be designed as an elongated, particularly tongue-shaped, elastically bendable flat part, particularly made of spring steel or elastic plastic, which can be elastically bent by the dynamic pressure from a resting state in which the flat part does not seal the sealing point, 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 point is designed to surround the outflow opening in a flat manner, in particular as a circular projection, and that the flat part is fastened to the closure element by a first section such that a second section of the flat part is spaced from the sealing point in the rest state. When the back pressure exceeds the predetermined value, the flat part is bent into a final state such that the second section seals the sealing point. Since the flow-dependent check valve has a flat sealing point and not just a sealing edge, this design is particularly robust and wear-resistant.

[0023] Furthermore, the blocking element can alternatively or additionally be designed as a receiver with a sliding portion, wherein the sliding portion is inserted into the outflow opening and guided axially displaceably therein, whereby the receiver is arranged axially displaceably on the closure element. This allows for particularly simple production of the flow-dependent check valve.

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

[0025] Furthermore, it can be provided that the sensor has an elastic sealing element, in particular an O-ring, wherein the sensor is moved into an end position when the back pressure exceeds the predetermined value, in which end position the elastic sealing element rests flat against the closure element, whereby the sensor seals the sealing point, wherein the contact surface of the closure element, against which the elastic sealing element rests for sealing, forms the sealing point. Since the flow-dependent check valve has a flat sealing point and not just a sealing edge, this design is particularly robust and wear-resistant. Furthermore, contamination in the sealing area can be covered by the elastic sealing element, whereby the sealing function is maintained even when the sealing point is dirty.

[0026] Preferably, a gas separation element is provided in the compensation housing between the closure element and the compensation body. This gas separation element completely covers the outflow opening or is inserted into the outflow opening, is made of a porous material or a wire mesh, and is wetted by the hydraulic fluid. The gas separation element has a predetermined bubble breakthrough pressure. The bubble breakthrough pressure is predetermined such that gas within the volume compensation element, which may be released, for example, by the rupture of a cavity in the compensation body after a plurality of compression and recovery processes over the course of its operating life, cannot exceed the predetermined bubble breakthrough pressure. As a result, the gas cannot penetrate the gas separation element and thus cannot flow out of the volume compensation element.Consequently, the gas separation element represents a particularly simple solution without the need for 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] Particularly preferably, the gas separation element is disk-shaped and / or made of a sintered material, in particular sintered spheres, and / or a twill weave. 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 an axis of rotation, a linearly displaceable piston which is coupled to the output shaft and rotates the output shaft when displaced, and a compression spring with a first end and a second end, which is supported with its first end on the piston and applies a compression spring force to the piston, in particular wherein the drive mechanism additionally comprises a spindle with a spindle plate, on which the second end of the compression spring is supported and via which spindle the compression spring force can be adjusted, wherein the volume compensation element is arranged in a space surrounded 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. It shows schematically Fig. 1 a first embodiment of a drive according to the invention with a volume compensation element with a compensation body, Fig. 2 the volume compensation element of the Fig. 1 in a non-compressed and a compressed state of the balancing body, Fig. 3 a compensating body with channel-like recesses, Fig. 4 a differential housing and a closure element, each with internal recesses, Fig. 5 a compensating body with a spherically structured surface, Fig. 6 a volume compensation element with a compensation body prestressed at a predefined temperature, Fig. 7 a detailed 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 detailed view of an exemplary alternative arrangement of the flow-dependent check valve of the Fig. 7, Fig. 9 a detailed view of a flow-dependent check valve with an elongated flat part in a rest state and a final state, Fig. 10 a perspective detailed view of the flow-dependent check valve of the 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 a volume compensation element with a gas separation element, Fig. 14 a perspective detailed view of the volume compensation element of the Fig. 13.

[0030] Fig. 1 shows a first embodiment of a drive 11 according to the invention with a drive mechanism 13 arranged at least partially in a drive housing 15 and with a volume compensation element 19. The drive mechanism 13 comprises an output shaft 77 rotatably mounted about a rotation axis, a linearly displaceable piston 79 which is coupled to the output shaft 77 and rotates the output shaft 77 upon displacement, and a compression spring 81. The compression spring 81 has a first end 83 and a second end 85, wherein the compression spring 81 is supported with its first end 83 on the piston 79 and applies a compression spring force to it. In addition, a spindle 87 with a spindle plate 89 is provided, 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.If the drive 13 is coupled to a vane, a rotary movement of the output shaft 77 is accompanied by a movement of the vane. In particular, to enable the setting of a defined damping behavior, a hydraulic fluid 17 in the form of oil is contained within the drive housing 15. A chamber 91 is surrounded by the compression spring 81. The chamber 91 is also flooded with the oil 17, with the volume compensation element 19 also being arranged in the chamber 91. The volume compensation element 19 serves to compensate for volume changes of the oil 17 resulting from temperature changes, in particular due to climatic conditions, thereby keeping the pressure within the drive 11 constant.

[0031] Fig. 2 shows the volume compensation element 19 of 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 temperature of, for example, 200°C. Furthermore, the volume compensation element 19 comprises a compensating housing 23 with a housing opening, into which the compensating body 21 is inserted, and a closure element 25, which closes the housing opening. The closure element 25 is provided with an outflow opening 27.

[0032] The upper illustration in Fig. Figure 2 shows the volume compensation element 19 in a state in which the compensation body 21 is not compressed and fills the interior of the volume compensation element 19. With an increase in temperature of the oil 17, its volume increases, whereby the oil 17 flows into the volume compensation element 19 via the outlet opening 27 and compresses the compensation body 21. The lower illustration in Fig. Figure 2 shows the volume compensation element 19 in a state in which the compensation body 21 is compressed. The additional volume within the volume compensation element 19 provided by the compression of the compensation body 21 serves to compensate for the increase in volume of the oil 17, whereby the pressure in the drive 11 remains constant. If the temperature of the oil 17 decreases, the oil 17 flows out of the volume compensation element 19 again, expanding the compensation body 21, with the restoring force of the compensation body 21 forcing the oil 17 out of the volume compensation element 19. The use of expanded thermoplastic polyurethane makes this displacement particularly reliable, since the expanded thermoplastic polyurethane has a high restoring force.Furthermore, the expanded thermoplastic polyurethane has high elasticity and long-term load capacity as well as high chemical resistance to the oil 17, which enables a long service life of the compensating body 21.

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

[0034] In addition to the described temperature-related volume changes of the oil 17, increased pressures occur within the drive 11 during operation of the drive 11 due to the movement of the piston 79 and the associated movement of the oil 17. The operational pressures typically exhibit a high pressure increase within a short period of time and a high absolute value. However, they do not pose a danger to the drive mechanism 13 or the drive housing 15, but rather are necessary for a defined damping behavior and interact closely with the damping behavior. In order to, on the one hand, prevent the damping behavior from being disrupted by compression of the compensating body 21, and on the other hand, to protect the compensating body 21 from operationally increased pressures, the closure element 25 further comprises a flow-dependent check valve 29.This closes the outflow opening 27 when a back pressure of the oil 17 occurring outside the volume compensation element 19 exceeds a predetermined value, so that no oil 17 can flow into the volume compensation element 19. The predetermined value is specified as a function of the operating pressures, in particular as a function of the back pressures occurring at the flow-dependent check valve 29 during operation. The back pressure depends in particular on the flow velocity of the hydraulic fluid. The functioning of the flow-dependent check valve 29 is explained with reference to the . Fig. 7 and Fig. 8, which each show a slightly modified flow-dependent check valve 29, but the mode of operation is nevertheless the same and refers to the closure element 25 and the flow-dependent check valve 29 according to Fig. 1 can be transferred.

[0035] In Fig. 3 shows another compensating body 21 of another embodiment of a drive 11 according to the invention, wherein the compensating body 21 has a plurality of channel-like recesses 31 formed on the surface of the compensating body 21 both in the axial direction and in the radial direction thereof. A plurality of 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 flow reliably to the outflow opening 27 of the closure element 25 via the flow paths, one of which is illustrated by an arrow. This prevents the compensating body 21 from closing the outflow opening 27 in certain positions of the drive 11 or the hydraulic fluid 17 from becoming 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 be reliably distributed within the volume compensation element 19 via the flow paths. This can, in particular, ensure 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. Fig. 4 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 a plurality of channel-like depressions 31 are formed on the inner wall in each case, which are analogous to the Fig. 2 form flow paths. Other components of the volume compensation element 19, except for the discharge opening 27, are shown in Fig. 4 not shown.

[0037] Another possibility for the formation of flow paths is in Fig. 5, which shows a compensating body 21 with a spherical structure on its surface. The compensating body 21 consists of an expanded particle foam, with the spherical structure 35 formed by the shape of the individual particles of the particle foam. This allows a multitude of flow paths, one of which is illustrated by the arrow, to be easily formed.

[0038] In a Fig. 6, of a further embodiment of a drive 11 according to the invention, it is provided that a compensating body 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 was accommodated in the drive housing 15 at a fluid temperature of, for example, 10°C, which hydraulic fluid 17 expanded when heated to the predefined temperature of 20°C such that the compensating body 21 is partially compressed or prestressed. If the temperature of the hydraulic fluid 17 drops 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 compensating element 19 with expansion of the compensating body 21 without a negative pressure developing in the drive 11.If, instead, a negative pressure were to occur in the drive 11, gases dissolved in the hydraulic fluid 17 could be released, which could disrupt or even cause the hydraulic damping functions to fail. The advantageous preload of the compensating body 21 prevents this, thus ensuring particularly reliable operation of the drive 11 over a wide temperature range, especially at low temperatures.

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

[0040] The left representation in Fig. 7 shows the flow-dependent check valve 29 in an open position, in which the flow-dependent check valve 29 does not close the outflow opening 27. The ball 47a is in a rest position, in which the ball 47a is spaced from the sealing edge 39 and the sealing edge 39 does not seal. The hydraulic fluid 17 can thus flow past the ball 47a and via the outflow opening 27 into the volume compensation element 19. In the process, 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 compressive force acts on the ball 47a, which attempts to displace the ball 47a towards the sealing edge 39. In contrast, the ball 47a is subjected to a counterforce provided by the spring force of the return spring 63.If the pressure force exceeds the spring force of the return spring 63, the ball 47a can be displaced from the rest position, whereby the return spring 63 is compressed.

[0041] If the dynamic pressure is above the specified value, the pressure force is so high compared to the spring force of the return spring 63 that the ball 47a is displaced into an end position, which is shown in the right-hand illustration of the Fig. 7. In this, the ball 47a seals the sealing edge 39, whereby the flow-dependent check valve 29 closes the outflow opening 27. If the pressure force decreases again below the spring force of the return spring 63, the ball 47a can be displaced back again by the spring force of the return spring 63. The ball 47a is then again spaced from the sealing edge 39, whereby the flow-dependent check valve 29 does not close the outflow opening 27. The predetermined value is predetermined in such a way and, in particular, the return spring 63 is dimensioned depending on the predetermined value in such a way that operational dynamic pressures displace the ball 47a into the end position, but dynamic pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

[0042] In Fig. 8 shows a detailed view of a closure element 25 with a flow-dependent check valve 29 of another embodiment of a drive 11 according to the invention, which has a function which corresponds to the one described above. Fig. 7. The closure element 25 according to Fig. 8 has in particular a first chamber 65, a second chamber 67 and a tapered section 69, via 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 taper.

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

[0044] The left representation in Fig. 9 shows the flow-dependent check valve 29 in an open state, in which the flow-dependent check valve 29 does not close the outflow opening 27. The flat part 49 is in a resting state, in which the second section 53 is spaced from the projection 41 and does not seal the projection 41. Accordingly, the hydraulic fluid 17 can flow past the flat part 49 and via the outflow opening 27 into the volume compensation element 19. In the process, a back pressure builds up on the flat part 49, which is dependent in particular on the flow velocity of the hydraulic fluid 17. Due to the back pressure, a compressive force acts on the flat part 49, which attempts to bend the flat part 49, in particular with the second section 53, in the direction of the projection 41. In contrast, the flat part 49 is subjected to a counterforce which is 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 the rest state.

[0045] If the dynamic pressure is above the specified value, the pressure 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 of the Fig. 9. In this, the second section 53 seals the projection 41, whereby the flow-dependent check valve 29 closes the outflow opening 27. If the pressure force decreases again below the restoring force of the flat part 49, the flat part 49 can reset itself so that the second section 53 is spaced from the projection 41, whereby the flow-dependent check valve 29 does not close the outflow opening 27. The predetermined value is predetermined in such a way and, in particular, the flat part 49 is dimensioned depending on the predetermined value in such a way that operational dynamic pressures bend the flat part 49 into the final state, but dynamic pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

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

[0047] Fig. 11 shows a detailed view of a closure element 25 with an alternative flow-dependent check valve 29 of a further embodiment of a drive 11 according to the invention. The closure element 25 has an outflow opening 27 and a receiver 55 with a sliding section 57, wherein the sliding section 57 is inserted into the outflow opening 27 and guided axially displaceably therein. Consequently, the receiver 55 is also arranged axially displaceably on the closure element 25. Furthermore, locking lugs (not designated in more detail) are formed on the sliding section 57 in order to prevent the sliding section 57 from accidentally slipping out of the outflow 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.In addition, the receiver 55 has an elastic sealing element 71 in the form of an O-ring and the closure element 25 has a support surface 43 provided for the sealing element 71, which can be sealed by the sealing element 71.

[0048] The left representation in Fig. 11 shows the flow-dependent check valve 29 in an open position, in which the flow-dependent check valve 29 does not close the outflow opening 27. The receiver 55 is in a rest position, in which the sealing element 71 is spaced from the support surface 43 and the support surface 43 does not seal. Accordingly, the hydraulic fluid 17 can flow past the sealing element 71 and via the outflow opening 27 into the volume compensation element 19. In the process, a back pressure builds up at the receiver 55, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to the back pressure, a compressive force acts on the receiver 55, which attempts to displace the receiver 55 with the sealing element 71 in the direction of the support surface 43, whereby the spring arms 59 are bent. In contrast, the sensor 55 is subjected to a counterforce which is provided by the restoring force of the spring arms 59.If the pressure force exceeds the restoring force of the spring arms 59, the sensor 55 can be moved from the rest position.

[0049] If the dynamic pressure is above 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 to an end position, which is shown in the right-hand illustration of the Fig. 11. In this, the sealing element 71 seals the support surface 43, whereby the flow-dependent check valve 29 closes the outflow opening 27. If the pressure force decreases again below the restoring force of the spring arms 59, the sensor 55 can be moved back again by the restoring force of the spring arms 59, so that the sealing element 71 is spaced from the support surface 43, whereby the flow-dependent check valve 29 does not close the outflow opening 27. The predetermined value is predetermined in such a way and, in particular, the spring arms 59 are dimensioned depending on the predetermined value in such a way that operationally related back pressures move the sensor 55 into the end position, but back pressures associated with temperature-related volume changes of the hydraulic fluid 17 do not.

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

[0051] In Fig. 13 shows a volume compensation element 19 of a further embodiment of a drive 11 according to the invention. This volume compensation element 19 essentially corresponds to that of the Fig. 1 and Fig. 2, wherein in the embodiment shown in Fig. 13, a disk-shaped gas separation element 75 is arranged between the closure element 25 and the compensating body 21, which completely covers the outflow opening 27 so that no hydraulic fluid 17 or gas can pass through the circumferential edge surface between the gas separation element 75 and the closure element 25. The gas separation element 75 consists of a porous sintered material and is wetted by the hydraulic fluid 17, whereby the gas separation element 75 has a predetermined bubble breakthrough pressure. The bubble breakthrough pressure is predetermined such that gas located within the volume compensation element 19, which gas can be released, for example, by rupturing a cavity in the compensating body 21 after a plurality of compression and recovery processes over the course of the operating period, cannot exceed the predetermined bubble breakthrough pressure.As a result, the gas cannot penetrate through the gas separation element 75 and thus cannot flow out of the volume compensation element 19.

[0052] Fig. 14 shows that in Fig. 13 shows a perspective detail view of the volume compensation element 19, in which the disc-shaped gas separation element 75 is shown in particular. Fig. 13 and Fig. 14, the gas separation element 75 represents a particularly simple solution without the need for further additional components and / or structures to prevent free gas from interfering with the hydraulic functions of the drive 11. List of reference symbols 11 Drive 13 Drive mechanism 15 drive housing 17 Hydraulic fluid 19 Volume compensation element 21 compensating bodies 23 differential housing 25 locking element 27 Outlet opening 29 flow-dependent check valve 31 Deepening 35 Structuring 37 Sealing point 39 Sealing edge 41 lead 43 contact surface 47 geometric bodies 47a ball 49 Flat part 51 first section 53 second section 55 sensors 57 sliding section 59 spring arm 61 free end 63 Return spring 65 First Chamber 67 Second Chamber 69 tapering section 71 Sealing element 75 Gas separation element 77 Output shaft 79 pistons 81 compression spring 83 first end 85 second end 87 spindle 89 spindle plate 91 Room

Claims

[1] Drive (11) for a wing of a window or a door, in particular a door closer, with a drive mechanism (13) for moving the wing, 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) which is 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) through which the hydraulic fluid (17) flows into the volume compensation element (19) upon an increase in the fluid temperature, compressing the compensating body (21), and flows out of the volume compensation element (19) upon a decrease in the fluid temperature, expanding the compensating 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 bythat the compensating body (21) on its surface and / or the compensating housing (23) on its inner wall and / or the closure element (25) has 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). [3] Drive (11) according to claim 2, characterized by that the spherical structuring (35) is formed by the particles of the particle foam. [4] 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. [5] Drive (11) according to one of the preceding claims, characterized bythat the 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. [6] 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) when cooled below the predefined temperature, with expansion of the compensating body (21). [7] Drive (11) according to one of the preceding claims, characterized bythat the 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 pressure 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 pressure force in such a way 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. [8] Drive (11) according to claim 7, characterized bythat the 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. [9] Drive (11) according to claim 8, 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). [10] Drive (11) according to claim 9, characterized bythat the 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 at a dynamic pressure above the predetermined value, in which end position the geometric body (47) seals the sealing point (37), [11] Drive (11) according to claim 7, characterized by that the 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. [12] Drive (11) according to claim 11, characterized by that the sealing point (37) is designed to surround the outflow opening (27) in a planar manner, in particular as a circular ring-shaped projection (41), and the flat part (49) is fastened to the closure element (25) with a first section (51) in such a way that a second section (53) of the flat part (49) is spaced apart from the sealing point (37) in the rest state, wherein the flat part (49) is bent into a final state at a dynamic pressure above the predetermined value in such a way that the second section seals the sealing point (37). [13] Drive (11) according to claim 7, 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 guided axially displaceably therein, whereby the receiver (55) is arranged axially displaceably on the closure element (25). [14] Drive (11) according to claim 13, characterized bythat 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, the restoring force of the spring arms (59) providing the counterforce. [15] Drive (11) according to claim 13 or 14, characterized by in that the receiver (55) has an elastic sealing element (71), in particular an O-ring, wherein the receiver (55) is displaced into an end position at a dynamic pressure above 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). [16] Drive (11) according to one of the preceding claims, characterized by in that a gas separation element (75) is provided in the compensation housing (23) between the closure element (25) and the compensation body (21), which gas separation element (75) 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). [17] Drive (11) according to claim 16, 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. [18] Drive (11) according to one of the preceding claims, characterized bythat the drive mechanism (13) comprises an output shaft (77) rotatably mounted about a rotational axis, a linearly displaceable piston (79) which is coupled to the output shaft (77) and rotates the output shaft (77) upon displacement, and a compression spring (81) with 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 thereto, 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 at least partially through the spindle (87) is formed.

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