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 a compensation housing which is at least partially filled with a gas, in particular air, wherein the compensation housing has an outlet opening through which the hydraulic fluid flows into the volume compensation element under compression of the gas when the fluid temperature increases and flows out of the volume compensation element under expansion of the gas when the fluid temperature decreases, wherein a rolling diaphragm is provided within the compensation housing.which keeps the gas enclosed in the compensation housing and hermetically separates it from the hydraulic fluid, and which, when the hydraulic fluid flows through the outlet opening, performs a stroke movement caused by the flowing hydraulic fluid, in which a head of the rolling diaphragm is linearly displaced.

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 received in the drive housing, according to the preamble of claim 1.

[0002] A drive of the type mentioned above is known from DE 195 15 169 A1.

[0003] 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.

[0004] Actuators for moving a window or door sash, especially door closers, are typically filled with a hydraulic fluid (mostly mineral oil-based) 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 out. Furthermore, excessive pressure could also lead to the actuator bursting.

[0005] To prevent pressure increases, it is known to not completely fill the actuator with hydraulic fluid, leaving a small amount of air inside. This air can be compressed when the hydraulic fluid expands, preventing an unacceptable pressure increase within the actuator. The air in the actuator also allows for pressure compensation during temperature fluctuations up to, for example, 70°C.

[0006] During operation of the drive, high pressure changes and / or flow velocities of the hydraulic fluid often occur when the drive mechanism is actuated, making the position and / or distribution of air within the drive undefined. As a result, air can accumulate at a point within the drive where it disrupts the hydraulic functions of the drive and / or causes audible noise.

[0007] DE 195 15 169 A1 discloses a door control device for use on the side of a fire door facing away from the fire, which is mounted in a door frame in a fire door safety assembly. The door control device comprises a door closer assembly filled with a hydraulic damping fluid and attached to the side of the fire door facing away from the fire by means of at least one fastening element, as well as a door control arm which is pivotably connected at a first end to the door frame and at a second end to the door closer assembly, wherein the hydraulic damping fluid comprises a fire-resistant hydraulic fluid.Furthermore, the door control device has a device for creating pressure equalization, such that when heated by contact of the door closer with the fire door, the hydraulic damping fluid inside the door closer occupies a volume with low pressure and that any pressure arising therein due to thermal expansion is relieved.

[0008] The invention is 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 hydraulic functions.

[0009] This problem is solved by a drive having the features of claim 1.

[0010] The drive has a volume compensation element which is arranged inside the drive housing, wherein the volume compensation element comprises a compensation housing which is at least partially filled with a gas, in particular air, wherein the compensation housing has an outlet opening through which the hydraulic fluid flows into the volume compensation element under compression of the gas when the fluid temperature increases and flows out of the volume compensation element under expansion of the gas when the fluid temperature decreases, wherein a rolling diaphragm is provided inside the compensation housing which keeps the gas enclosed in the compensation housing and hermetically separates it from the hydraulic fluid and which, when the hydraulic fluid flows through the outlet opening, performs a stroke movement caused by the flowing hydraulic fluid, in which a head of the rolling diaphragm is linearly displaced.

[0011] If the temperature of the hydraulic fluid increases, for example due to sunlight, the hydraulic fluid expands and flows into the volume compensation element. The rolling diaphragm then performs a reciprocating movement caused by the flowing hydraulic fluid. During this movement, the head of the rolling diaphragm is linearly displaced by rolling the diaphragm, thus compressing the gas. This releases additional volume for the hydraulic fluid, preventing the pressure in the drive from increasing.

[0012] The drive according to the invention therefore enables pressure equalization over a large temperature range without free air in the drive and thus without disturbance of the hydraulic functions, since the gas is held enclosed by the rolling diaphragm in the compensation housing and hermetically separated from the hydraulic fluid.

[0013] Furthermore, the outlet can act as a throttle, limiting the flow rate of the hydraulic fluid through it. This limits the impact of sudden pressure increases, such as those that can occur when the impeller moves within the actuator, on the rolling diaphragm. Conversely, slow, temperature-related volume changes of the hydraulic fluid generate a flow rate that can pass through the outlet unimpeded. Consequently, the outlet does not significantly affect the hydraulic function during actuator operation, despite the inherent volume compensation capability. It also limits the pressures acting on the rolling diaphragm, resulting in a long service life for the actuator.

[0014] Furthermore, since a rolling diaphragm is provided according to the invention, it does not experience any significant stretching due to the reciprocating movement of the rolling diaphragm, as the rolling diaphragm is only subjected to minimal stress due to the rolling action, thereby increasing the reliability and operational safety of the drive. In contrast, with stretching, for example similar to that of a balloon, the material stresses would be significantly higher, and thus the reliability and operational safety would be reduced.

[0015] 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 according to the invention for realizing the volume compensation.

[0016] The compensating housing includes a closure element with a flow-dependent check valve that closes the outlet when the back pressure of the hydraulic fluid outside the compensating element exceeds a predetermined value, thus preventing hydraulic fluid from flowing into the compensating element. In principle, the back pressure depends primarily on the flow velocity of the hydraulic fluid, with high flow velocities and consequently high back pressure occurring during operation of the actuator due to piston movement.Since the flow-dependent check valve closes the outlet when the hydraulic fluid back pressure outside the volume compensation element exceeds a predefined 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 rolling diaphragm. Conversely, slow, temperature-induced volume changes of the hydraulic fluid generally generate no or only negligible back pressures below the predefined value. At these levels, 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 actuator operation, despite providing volume compensation functionality.Furthermore, the rolling diaphragm itself is also protected from high pressures, resulting in a particularly long service life for the drive.

[0017] Advantageous embodiments of the invention will become apparent from the dependent claims, the description and the figures.

[0018] It can be provided that the rolling diaphragm comprises an inner surface which at least partially contacts the gas and an outer surface which at least partially rests against the inner wall of the compensation housing, and is designed such that a rolling area of ​​the diaphragm rolls along the inner wall during the stroke movement, forming a rolling fold with either the outer or the inner surface. Accordingly, the rolling behavior of the two designs differs, with each enabling controlled rolling and thus increasing the reliability of the drive.

[0019] Advantageously, the rolling diaphragm at the head has a greater material thickness than the walking area. This reinforcement improves force transmission into the rolling diaphragm and prevents deformation in certain areas, particularly at the head, thus improving the controlled rolling of the diaphragm.

[0020] Furthermore, a support element can be provided within the compensation housing, which is rigidly connected to the head, in particular wherein the support element is linearly displaceable against the compensation housing. The support element assists the controlled rolling of the diaphragm, and in particular, the linearly displaceable support element improves the controlled rolling by guiding the diaphragm. Moreover, the support element provides reinforcement with the advantages described above.

[0021] Advantageously, the rolling diaphragm includes a sealing ring with which it is attached to the compensation housing, particularly by injection molding. This increases the reliability of the volume compensation element and simplifies its manufacturing. Furthermore, it allows pressure equalization even under particularly large temperature fluctuations.

[0022] Preferably, the compensating housing comprises a first housing shell and a second housing shell, which are connected to each other at a joint such that the hydraulic fluid cannot penetrate the compensating housing at the joint. The shell design simplifies the manufacturing of the volume compensation element, such as the provision of the rolling diaphragm.

[0023] Furthermore, at the connection point, the first housing shell can have a first sealing surface and the second housing shell a second sealing surface, with the sealing ring of the rolling diaphragm being clamped between the first and second sealing surfaces. This design further increases the reliability of the volume compensation element.

[0024] Preferably, the rolling membrane consists of a thermoplastic elastomer, most preferably a thermoplastic polyurethane. This ensures high flexibility across a wide temperature range, high wear resistance, and thus high functional reliability. Alternatively, the rolling membrane can be made of a rubber elastomer, which, due to its material properties, allows for even greater functional reliability. Alternatively or additionally, a fabric can be incorporated into the membrane. This increases its robustness and reduces its elasticity, thereby also increasing functional reliability and improving controlled unwinding.

[0025] Advantageously, the amount of hydraulic fluid is measured such that at a hydraulic fluid temperature corresponding to a predefined temperature, in particular 20°C, the gas within the hydraulic fluid is partially compressed. This causes the hydraulic fluid to flow out of the volume compensation element when it cools below the predefined temperature, accompanied by gas expansion. For example, during the manufacturing 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. This ensures that the gas is partially compressed, i.e., pre-pressurized, 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 gas 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 expelled, potentially disrupting or even causing the hydraulic damping functions to fail. The advantageous gas pre-charge prevents this, thus ensuring particularly reliable actuator operation over a wide temperature range, especially at low temperatures.

[0026] Naturally, it is advantageous if the predefined temperature corresponds, for example, to the usual room temperature at the operating location of the drive.

[0027] Preferably, 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 vane 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The design may include a sealing surface surrounding the outlet opening, particularly as an annular projection, and a flat section attached to the closure element such that a second section of the flat section is spaced away from the sealing surface in its resting state. When the back pressure exceeds a specified value, the flat section bends into a final position, causing the second section to seal the sealing surface. Because the flow-dependent check valve has a flat sealing surface and not merely a sealing edge, this design is particularly robust and wear-resistant.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The invention is described below by way of example with reference to the figures. These show schematically... Fig. 1 shows a sectional view of a first embodiment of a drive according to the invention with a volume compensation element with a rolling diaphragm, Fig. 2 shows a sectional view of the volume compensation element made of Fig. 1 in two different states, Fig. 3 a sectional view of a volume compensation element of a second embodiment of a drive according to the invention in two different states, Fig. 4 a sectional view of a volume compensation element of a third embodiment of a drive according to the invention in two different states, Fig. 5 a sectional view of a volume compensation element of a fourth embodiment of a drive according to the invention, Fig. 6 a sectional view of a volume compensation element of a fifth embodiment of a drive according to the invention with gas already compressed at a predefined temperature, Fig. 7 a sectional 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 sectional detail view of an exemplary alternative arrangement of the flow-dependent check valve made of Fig. 7 Fig. 9 a cutaway detail view of a flow-dependent check valve with an elongated flat part in a rest state and a final state, Fig. 10 a perspective detail view of the flow-dependent check valve made of Fig. 9 Fig. 11 shows a cutaway detail view of a flow-dependent check valve with a sensor in a rest position and an end position, and Fig. 12 shows a perspective detail view of the flow-dependent check valve. Fig. 11 .

[0038] 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 11 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.

[0039] Fig. 2 The volume compensation element 19 shows Fig. 1 in two different states, with the constructive structure first being explained using the illustration above.

[0040] The volume compensation element 19 comprises a compensation housing 23 with a first housing shell 23a and a second housing shell 23b, which is partially filled with a gas 20 in the form of air. A rolling diaphragm 21, made of a thermoplastic polyurethane, is also provided within the compensation housing 23. The rolling diaphragm 21 has a sealing ring 34, with which the rolling diaphragm 21 is injection-molded onto the compensation housing 23, in particular the second housing shell 23b. The rolling diaphragm 21 also has a head 30, which can also be referred to as the diaphragm base or base, and a flexing area 31, wherein the rolling diaphragm 21 has a material thickness at the head 30 that is greater than that of the flexing area 31.Furthermore, the rolling diaphragm 21 comprises an inner surface 21a, which contacts the air 20, and an outer surface 21b, with which the rolling diaphragm 21 rests against the inner wall of the expansion housing 23, in particular the second housing shell 23b. The first housing shell 23a and the second housing shell 23b are connected to each other at a joint 75, for example by welding, such that the oil 17 cannot penetrate the expansion housing 23 at the joint 75. In this embodiment, the first housing shell 23a also has a first sealing surface 35 and the second housing shell 23b has a second sealing surface 36 at the joint 75, with the sealing ring 34 of the rolling diaphragm 21 being clamped between the first sealing surface 35 and the second sealing surface 36. On the other hand, the compensation housing 23, in particular the second housing shell 23b, has a drainage opening 27 through which the oil 17 can generally flow.The air 20, on the other hand, is held enclosed by the rolling diaphragm 21 in the compensation housing 23 and hermetically separated from the oil 17.

[0041] The upper representation in Fig. 2 The volume compensation element 19 is shown in a state in which no oil 17 has yet flowed into the volume compensation element 19 through the outflow opening 27.

[0042] As the temperature of the oil 17 increases, it expands, thereby increasing its volume. The lower illustration in Fig. 2 The volume compensation element 19 is shown in a state in which the oil 17, upon an increase in fluid temperature, flows into the volume compensation element 19 through the outflow opening 27, expanding as it does so. The rolling diaphragm 21 performs a stroke caused by the flowing oil 17, during which the head 30 of the rolling diaphragm 21 is displaced linearly to the right in the illustration. Simultaneously, the volume of the air 20 held by the rolling diaphragm 21 in the compensation housing 23 decreases during this stroke. Thus, in the lower illustration, the oil flows into... Fig. 2 As the fluid temperature increases, the oil 17 flows through the outlet opening 27 into the volume compensation element 19 under compression of the air 20. Due to the stroke movement of the rolling diaphragm 21, an additional volume corresponding to the expansion of the oil 17 as the temperature increases is released, so that the pressure in the drive 11 does not rise.

[0043] As the fluid temperature decreases again, the volume of the oil 17 also decreases. Due to the pressure ratio between the compressed air 20 on the one hand and the cooling oil 17 on the other, the rolling diaphragm 21 performs a reciprocating movement, during which the head 30 of the rolling diaphragm 21 is shown in the lower illustration. Fig. 2 The position is shifted linearly to the left. Thus, during this stroke movement, as the fluid temperature decreases, the oil 17 flows out of the volume compensation element 19 through the outflow opening 27, accompanied by the expansion of the air 20.

[0044] During lifting movements of this embodiment, the rolling area 31 of the rolling diaphragm 21 rolls along the inner wall of the compensating housing 23, in particular the second housing shell 23b, forming a roll fold 33. Generally, the rolling diaphragm 21 does not experience any significant stretching due to the lifting movement, as the rolling diaphragm 21 is only subjected to minimal stress, thus increasing the reliability and operational safety of the drive 11. The rolling diaphragm 21 is designed for controlled rolling, in particular by the rolling area and the increased material thickness of the head 30, although other types of reinforcement of the head 30, for example by an incorporated fabric or a support element, are also conceivable.

[0045] In the event of a fire, the rolling diaphragm 21 performs a stroke movement due to the typically high temperatures of a fire, exceeding a normal working stroke, for example, due to solar radiation. In this way, an additional volume can be provided for the expanding oil 17 in the event of a fire, enabling the actuator 11 to withstand such high temperatures without leakage.

[0046] Fig. 3 The volume compensation element 19 of a second embodiment of a drive 11 according to the invention is shown, wherein, in contrast to the volume compensation element 19, it is made of Fig. 2 A rolling area 31 of the rolling diaphragm 21 rolls during a lifting movement, forming a rolling fold 33 with an inner surface 21a of the rolling diaphragm 21 against an inner wall of the compensating housing 23, in particular the first housing shell 23a. Fig. 3 Here, two states are simultaneously depicted: a state in which no hydraulic fluid 17 flows into the volume compensation element 19, and a state in which the rolling diaphragm 21 performs a stroke movement caused by the flowing hydraulic fluid 17, in which the head 30 of the rolling diaphragm 21 is shown in the illustration according to Fig. 3 is shifted linearly to the right.

[0047] Fig. 4 The volume compensation element 19 of a third embodiment of a drive 11 according to the invention is shown, in which, in contrast to the volume compensation element 19, Fig. 3 A support element 93 is provided which is firmly connected, for example by bonding, to the head 30 of the rolling membrane 21. As in Fig. 3 are also in Fig. 4 Two states of the volume compensation element 19 are shown simultaneously. Since the support element 93 facilitates controlled rolling of the rolling membrane 21, the rolling membrane 21 does not have an increased material thickness at the head 30 compared to the material thickness of a flex area 31 of the rolling membrane 21. In addition, the support element 93 can be linearly displaceable on the compensation housing 23, which in Fig. 4 However, it is not shown.

[0048] Fig. 5 Figure 1 shows the volume compensation element 19 of a fourth embodiment of a drive 11 according to the invention, which is in the same state as the volume compensation element 19 of the lower illustration. Fig. 2 The rolling membrane 21 of the volume compensation element 19 is also located there. Fig. 5 The assembly comprises a sealing ring 34 which is clamped at a connection point 75 between a first sealing surface 35 of a first housing shell 23a and a second sealing surface 36 of a second housing shell 23b. The rolling diaphragm 21, unlike the one in Fig. 2 shown rolling membrane 21 made of a rubber elastomer, wherein in addition a Fig. 5 Tissue not shown is incorporated into the rolling membrane 21.

[0049] Fig. 6 Figure 1 shows the volume compensation element 19 of a fifth embodiment of a drive 11 according to the invention, in which the gas 20 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 the hydraulic fluid 17 was heated to the predefined temperature of 20 °C, it expanded such that the gas 20 was partially compressed or pre-tensioned as a result of a stroke movement of the rolling diaphragm 21. 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 through the outflow opening 27 as the gas 20 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, potentially disrupting or even causing the hydraulic damping functions to fail. The advantageous pre-charge of the gas 20 prevents this, thus ensuring particularly reliable operation of the actuator 11 over a wide temperature range, especially at low temperatures.

[0050] In addition to the temperature-related volume changes of the hydraulic fluid 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 hydraulic fluid 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 risk 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 gas 20 and to protect the rolling diaphragm 21 from operationally increased pressures, the volume compensation element 19 is designed so that the compensation housing 23 includes a closure element 25 which incorporates a flow-dependent check valve 29.The flow-dependent check valve 29 closes the outlet opening 27 when the back pressure of the hydraulic fluid 17 occurring outside the volume compensation element 19 exceeds a predetermined value, thus preventing any hydraulic fluid 17 from flowing into the volume compensation element 19. The predetermined value depends on the operating pressures, in particular on the back pressures occurring at the flow-dependent check valve 29 during operation. The back pressure is especially dependent on the flow velocity of the hydraulic fluid 17, with the back pressure increasing with the flow velocity.

[0051] Fig. 7 This relates to a sixth embodiment of a drive 11 according to the invention, the compensating housing 23 of which comprises a closure element 25 with a flow-dependent check valve 29, wherein only a detailed view of the closure element 25 with the flow-dependent check valve 29 is shown. The closure element 25 has a first chamber 65, a second chamber 67 into which the 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, which is arranged in the second chamber 67. In addition, a circular sealing edge 39 is formed on the tapered section 69, which can be sealed by the sphere 47a and thus forms a sealing point.

[0052] The left-hand representation in Fig. 7 The flow-dependent check valve 29 is shown 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 against the sealing edge 39. At low flow velocities, 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.

[0053] 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.

[0054] 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 predetermined, and in particular the return spring 63 is dimensioned according to this predetermined value, such that operational back pressures move the ball 47a into its end position. However, temperature-related volume changes of the hydraulic fluid 17 result in no or only negligible back pressures.

[0055] Fig. 8 This relates to a seventh embodiment of a drive 11 according to the invention, the compensating housing 23 of which comprises an alternative closure element 25 with a flow-dependent check valve 29, wherein only a detailed view of the closure element 25 with the flow-dependent check valve 29 is shown. The operation of the flow-dependent check valve 29 is analogous to that described above. Fig. 7 The described function also applies to the locking element 25 as described. 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.

[0056] Fig. 9 This relates to an eighth embodiment of a drive 11 according to the invention, the compensating housing 23 of which comprises an alternative closure element 25 with a flow-dependent check valve 29, wherein only a detailed view of the closure element 25 with the flow-dependent check valve 29 is shown. 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, the sealing point is provided on the closure element 25 in the form of an annular projection 41 surrounding the outflow opening 27, which can be sealed by a second section 53 of the flat part 49.

[0057] 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, at low flow velocities, the hydraulic fluid 17 can flow past the flat part 49 and through the outlet opening 27 into the volume compensation element 19. A dynamic pressure builds up on the flat part 49, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to this dynamic pressure, a pressure force acts on the flat part 49, which attempts to bend the flat part 49, especially with regard to 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.

[0058] 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, thus preventing the flow-dependent check valve 29 from closing the outlet 27. The specified value is predetermined, and in particular the flat part 49 is dimensioned according to this predetermined value, such that operational back pressures bend the flat part 49 into its final state. However, temperature-related volume changes of the hydraulic fluid 17 result in no or only negligible back pressures.

[0059] 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.

[0060] Fig. 11 This relates to a ninth embodiment of a drive 11 according to the invention, the compensating housing 23 of which comprises an alternative closure element 25 with a flow-dependent check valve 29. Again, only a detailed view of the closure element 25 with the flow-dependent check valve 29 is shown. The closure element 25 has a sensor 55 with a sliding section 57, the sliding section 57 being inserted into the outflow opening 27 and guided axially displaceably therein. Consequently, the sensor 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 from the outflow opening 27. In addition, two elastic spring arms 59 are formed on the sensor 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 and forms the sealing point.

[0061] 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, at low flow velocities, the hydraulic fluid 17 can flow past the sealing element 71 and through the outlet opening 27 into the volume compensation element 19. This creates a back pressure on the sensor 55, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to this back pressure, a compressive 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 sensor 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 sensor 55 can be moved from its rest position.

[0062] 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. Fig. 11 As shown, the sealing element 71 seals the contact surface 43, causing the flow-dependent check valve 29 to close the outlet 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 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. However, temperature-related volume changes of the hydraulic fluid 17 result in no or only negligible back pressures.

[0063] 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 receiver 55 with the sealing element 71 and the design of the spring arms 59 are shown. Bezugszeichenliste

[0064] 11 Actuator 13 Actuator mechanism 15 Actuator housing 17 Hydraulic fluid 19 Volume compensation element 20 Gas 21 Rolling diaphragm 21a Inner side 21b Outer side 23 Compensating housing 23a First housing shell 23b Second housing shell 25 Closing element 27 Outlet opening 29 Flow-dependent check valve 30 Head 31 Rolling area 33 Roll fold 34 Sealing ring 35 First sealing surface 36 Second sealing surface 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 Connection point 77 Output shaft 79 Piston 81 Compression spring 83 First end 85 Second end 87 Spindle 89 Spindle plate 91 Space 93 Support element

Claims

1. Drive (11) for a leaf of a window or of a door, in particular a door closing device, having a drive mechanism (13) for moving the leaf, a drive housing (15) in which the drive mechanism (13) is at least partially disposed, a hydraulic fluid (17), in particular oil, which is received in the drive housing (15), and a volumetric compensation element (19) which is disposed within the drive housing (15), wherein the volumetric compensation element (19) comprises a compensation housing (23) which is at least partially filled with a gas (20), in particular air, wherein the compensation housing (23) has an outflow opening (27) through which the hydraulic fluid (17), while compressing the gas (20), flows into the volumetric compensation element (19) in the event of an increase in the fluid temperature and, while expanding the gas (20), flows out of the volumetric compensation element (19) in the event of a reduction in the fluid temperature, wherein provided within the compensation housing (23) is a rolling diaphragm (21) which keeps the gas (20) enclosed in the compensation housing (23) and hermetically separates it from the hydraulic fluid (17) and which, when the hydraulic fluid (17) flows through the outflow opening (27), performs a stroke movement which is caused by the flowing hydraulic fluid (17) and during which a head (30) of the rolling diaphragm (21) is displaced linearly, characterized in that the compensation housing (23) comprises a closure element (25) which has a flow-dependent check valve (29) that closes the outflow opening (27) when a dynamic pressure of the hydraulic fluid (17) prevalent outside the volumetric compensation element (19) exceeds a predefined value, such that no hydraulic fluid (17) can flow into the volumetric compensation element (19).

2. Drive (11) according to Claim 1, characterized in that the rolling diaphragm (21) comprises an internal side (21a) which is at least partially in contact with the gas (20), and an external side (21b) by way of which the rolling diaphragm (21) bears at least partially on the internal wall of the compensation housing (23); and is designed in such a manner that during the stroke movement a tumbling region (31) of the rolling diaphragm (21) rolls on the internal wall by way of the external side (21b) or by way of the internal side (21a) while forming a rolling fold (33).

3. Drive (11) according to one of the preceding claims, characterized in that the rolling diaphragm (21) has, on the head (30), a material thickness which is increased in relation to the material thickness of the tumbling region (31).

4. Drive (11) according to one of the preceding claims, characterized in that provided within the compensation housing (23) is a supporting element (93) which is fixedly connected to the head (30), in particular wherein the supporting element (93) is supported on the compensation housing (23) in a linearly displaceable manner.

5. Drive (11) according to one of the preceding claims, characterized in that the rolling diaphragm (21) comprises a seal ring (34) by way of which the rolling diaphragm (21) is fastened to the compensation housing (23), in particular injection-moulded on the latter.

6. Drive (11) according to one of the preceding claims, characterized in that the compensation housing (23) comprises a first housing shell (23a) and a second housing shell (23b), which are connected to one another at a connection point (75) in such a manner that the hydraulic fluid (17) cannot enter the compensation housing (23) at the connection point (75).

7. Drive (11) according to Claim 5 and Claim 6, characterized in that at the connection point (75) the first housing shell (23a) has a first sealing surface (35) and the second housing shell (23b) has a second sealing surface (36), wherein the seal ring (34) of the rolling diaphragm (21) is clamped between the first sealing surface (35) and the second sealing surface (36).

8. Drive (11) according to one of the preceding claims, characterized in that the rolling diaphragm (21) is composed of a thermoplastic elastomer, preferably of a thermoplastic polyurethane, or of a rubber elastomer, and / or in that a woven fabric is incorporated into the rolling diaphragm (21).

9. Drive (11) according to one of the preceding claims, characterized in that the amount of substance of the hydraulic fluid (17) is sized in such a manner that at a hydraulic fluid temperature corresponding to a predefined temperature, in particular of 20°C, the gas (20) is partially compressed by the hydraulic fluid (17), as a result of which the hydraulic fluid (17) when cooling below the predefined temperature flows out of the volumetric compensation element (19) while expanding the gas (20).

10. Drive (11) according to one of the preceding claims, characterized in that the flow-dependent check valve (29) comprises a sealing point (39; 41; 43) and a blocking element (47; 49; 55) by means of which the sealing point (39; 41; 43) is able to be sealed, wherein a compression force dependent on the dynamic pressure acts on the blocking element (47; 49; 55) and the blocking element (47; 49; 55) is impinged with a counterforce opposing the compression force in such a manner that, when the dynamic pressure is below the predefined value, the blocking element (47; 49; 55) does not seal the sealing point (39; 41; 43), as a result of which the flow-dependent check valve (29) does not close the outflow opening (27), or, when the dynamic pressure exceeds the predefined value, the blocking element (47; 49; 55) seals the sealing point (39; 41; 43), as a result of which the flow-dependent check valve (29) closes the outflow opening (27); optionally wherein the blocking element is embodied 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 off the sealing point (39), and provided is a separately formed restoring spring (63) which acts on the geometric body (47), wherein the spring force of the restoring spring (63) provides the counterforce; furthermore optionally wherein the closure element (25) has a first chamber (65) in which the geometric body (47) is received, a second chamber (67) into which the outflow opening (27) opens and in which the restoring spring (63) is disposed, and a tapered portion (69) by way of which the first chamber (65) tapers towards the second chamber (67); furthermore optionally wherein the sealing point (39) is formed on the tapered portion (69), in particular as a circular sealing edge (39), and the geometric body (47) is received in the first chamber (65) in such a manner that, in the rest position, the geometric body (47) is spaced apart from the sealing point (39), wherein, in the event of a dynamic pressure exceeding the predefined value, the geometric body (47) is displaced into a terminal position in which the geometric body (47) seals the sealing point (39).

11. Drive (11) according to Claim 10, characterized in that the blocking element is embodied as an elongate, in particular tongue-shaped, elastically bendable flat part (49), which is in particular composed of spring sheet or elastic plastic and can be elastically bent by the dynamic pressure from a rest state in which the flat part (49) does not seal the sealing point (41), wherein the restoring force of the flat part (49) provides the counterforce; optionally wherein the sealing point (41) is formed so as to surround the outflow opening (27) in a planar manner, in particular as a circular-annular projection (41), and the flat part (49) is fastened to the closure element (25) by way of a first section (51), in that a second section (53) of the flat part (49) is spaced apart from the sealing point (41) in the rest state, wherein the flat part (49) is bent into a final state in the event of a dynamic pressure exceeding the predefined value in such a manner that the second section seals the sealing point (41).

12. Drive (11) according to Claim 10, characterized in that the blocking element is embodied as a receptacle (55) with a sliding portion (57), wherein the sliding portion (57) is inserted into the outflow opening (27) and guided in an axially displaceable manner therein, as a result of which the receptacle (55) is disposed in an axially displaceable manner on the closure element (25).

13. Drive (11) according to Claim 12, characterized in that formed on the receptacle (55) are elastic spring arms (59), the free ends (61) of which bear on the closure element (25), and which can be displaced by the dynamic pressure from a rest position in which the receptacle (55) does not seal the sealing point (43), as a result of which the spring arms (59) are bent, wherein the restoring force of the spring arms (59) provides the counterforce; and / or in that the receptacle (55) has an elastic sealing element (71), in particular an O-ring, wherein the receptacle (55), in the event of a dynamic pressure exceeding the predefined value, is displaced into a terminal position in which the elastic sealing element (71) bears flat on the closure element (25), as a result of which the receptacle (55) seals the sealing point (43), wherein the contact surface (43) of the closure element, on which the elastic sealing element (71) bears for sealing purposes, forms the sealing point (43).

14. Drive (11) according to one of the preceding claims, characterized in that the drive mechanism (13) has an output shaft (77) which is mounted so as to be rotatable about a rotation axis, a linearly displaceable piston (79) which is coupled to the output shaft (77) and rotates the output shaft (77) in the event of a displacement, and a compression spring (81) which has a first end (83) and a second end (85) and is supported by way of its first end (83) on the piston (79) and acts on the latter with a compression spring force, 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 by way of which spindle (87) the compression spring force can be set, wherein the volumetric compensation element (19) is disposed in a space (91) helically surrounded by the compression spring (81) and / or within the spindle (87) and / or is formed at least partially by the spindle (87).

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