Drive for a sash of a window or door

Abstract

The invention relates to a drive for a window or door sash, 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 outflow 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 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 mineral oil-based) 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, causing the hydraulic fluid to leak out. Furthermore, excessive pressure could also cause the drive to burst.

[0004] To prevent a pressure increase, it is well known that the drive is not completely filled with hydraulic fluid, so a small amount of air is retained in the drive. This air can be compressed when the hydraulic fluid expands without causing the pressure in the drive to rise excessively. The air in the drive can achieve pressure compensation for temperature fluctuations of up to, for example, 70°C.

[0005] During operation of the drive, large pressure changes and / or flow velocities of the hydraulic fluid often occur when the drive mechanism is actuated, resulting in an imprecise position and / or distribution of the air within the drive. As a result, the air can collect in one location within the drive, causing disruption of the drive's hydraulic functions and / or audible noise.

[0006] 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 hydraulic functions are not disturbed.

[0007] This object is achieved by a drive having the features of claim 1, and in particular in that the drive has 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 outflow opening through which the hydraulic fluid flows into the volume compensation element upon an increase in the fluid temperature, compressing the gas, and flows out of the volume compensation element upon a decrease in the fluid temperature, expanding the gas, 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 outflow opening, executes a lifting movement caused by the flowing hydraulic fluid,in which a head of the rolling diaphragm is displaced linearly.

[0008] 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 performs a reciprocating movement caused by the flowing hydraulic fluid. During this movement, the head of the rolling diaphragm is displaced linearly as the diaphragm rolls, compressing the gas. This releases additional volume for the hydraulic fluid, preventing pressure in the drive from increasing.

[0009] The drive according to the invention therefore enables pressure equalization over a wide temperature range without free air in the drive and thus without disruption of the hydraulic functions, since the gas is kept enclosed by the rolling diaphragm in the compensation housing and hermetically separated from the hydraulic fluid.

[0010] Furthermore, the discharge opening can act as a throttle, limiting the volume flow of hydraulic fluid through the discharge opening. This means that sudden pressure surges, such as those that can occur when the vane in the actuator moves, have only a limited effect on the rolling diaphragm. In contrast, slow, temperature-induced volume changes in the hydraulic fluid generate a volume flow that can essentially flow unhindered through the discharge opening. Consequently, thanks to the discharge opening, the hydraulic function during operation of the actuator is not significantly affected—despite the volume compensation functionality provided. Furthermore, the pressures acting on the rolling diaphragm are also limited, resulting in a long service life for the actuator.

[0011] Furthermore, since the invention provides a rolling diaphragm, the diaphragm's reciprocating motion does not experience any significant stretching, as the rolling diaphragm is subjected to only minimal stress due to rolling, thus increasing the reliability and functional safety of the drive. In contrast, if the diaphragm were to stretch, similar to a balloon, for example, the material stresses would be significantly higher, thus reducing reliability and functional safety.

[0012] 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 according to the invention for realizing the volume compensation.

[0013] Advantageous embodiments of the invention emerge from the subclaims, the description and the figures.

[0014] The rolling diaphragm can be configured to have an inner side, which at least partially contacts the gas, and an outer side, with which the rolling diaphragm at least partially rests against the inner wall of the differential housing. The rolling diaphragm is configured such that a flexed area of ​​the rolling diaphragm rolls against the inner wall during the stroke movement, forming a rolling fold with the outer side or with the inner side. Accordingly, the rolling behavior of the two designs is different, with each enabling controlled rolling and thus increasing the reliability of the drive.

[0015] Advantageously, the rolling membrane has a greater material thickness at the head than the material thickness of the flexed area. This reinforcement improves the transmission of force to the rolling membrane and prevents deformation in certain areas, particularly in the head, thus improving the controlled unwinding of the rolling membrane.

[0016] Furthermore, a support element can be provided within the differential housing, which is firmly connected to the head, in particular wherein the support element is supported on the differential housing in a linearly displaceable manner. The support element can assist the controlled unwinding of the rolling diaphragm, wherein, in particular, the linearly displaceably supported support element improves the controlled unwinding by guiding the rolling diaphragm. Furthermore, the support element represents a reinforcement with the advantages described above.

[0017] The rolling diaphragm advantageously includes a sealing ring with which the rolling diaphragm is attached, in particular molded, to the differential housing. This increases the reliability of the volume compensation element and simplifies its production. Furthermore, it can also achieve pressure compensation for particularly large temperature fluctuations.

[0018] The differential housing preferably comprises a first housing shell and a second housing shell, which are connected to one another at a connection point such that the hydraulic fluid cannot penetrate into the differential housing at the connection point. The shell structure can simplify the manufacture of the volume compensation element, such as the provision of the rolling diaphragm.

[0019] Furthermore, at the connection point, the first housing shell can have a first sealing surface and the second housing shell can have a second sealing surface, with the sealing ring of the rolling diaphragm being clamped between the first sealing surface and the second sealing surface. This design can further increase the reliability of the volume compensation element.

[0020] The rolling diaphragm is preferably made of a thermoplastic elastomer, particularly preferably a thermoplastic polyurethane. This ensures high flexibility over a wide temperature range, high wear resistance, and thus high functional reliability. Alternatively, the rolling diaphragm can be made of a rubber elastomer, which, due to its material properties, can achieve even greater functional reliability. Alternatively or additionally, a fabric can be incorporated into the diaphragm. This can increase the robustness and reduce the extensibility of the rolling diaphragm, thereby also increasing functional reliability and improving controlled unwinding.

[0021] Advantageously, the amount of hydraulic fluid is such that, at a hydraulic fluid temperature corresponding to a predefined temperature, in particular 20°C, the gas is partially compressed by the hydraulic fluid, whereby, upon cooling below the predefined temperature, the hydraulic fluid flows out of the volume compensation element with the gas expanding. 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 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, allowing the hydraulic fluid to flow out of the volume compensation element as the gas expands, without creating a vacuum in the drive. If a vacuum were to occur in the drive instead, gases dissolved in the hydraulic fluid could be released, disrupting or even causing the hydraulic damping functions to fail. The advantageous preload of the gas prevents this, ensuring particularly reliable drive operation over a wide temperature range, especially at low temperatures.

[0022] Of course, it is advantageous if the predefined temperature corresponds, for example, to the usual room temperature at the operating location of the drive.

[0023] Preferably, the compensation housing comprises a closure element having a flow-dependent check valve that 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. In principle, the back pressure depends in particular on the flow velocity of the hydraulic fluid, with high flow velocities and thus a high back pressure occurring during operation of the drive due to a movement of the piston.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 in the drive moves, cannot act on the rolling diaphragm. In contrast, slow, temperature-related volume changes in the hydraulic fluid generally generate no or only 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 drive operation - despite the volume compensation functionality provided.On the other hand, the rolling diaphragm itself is protected from high pressures, which results in a particularly long service life of the drive.

[0024] The flow-dependent check valve preferably 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The blocking element can alternatively or additionally be designed as an elongated, particularly tongue-shaped, elastically bendable flat part, particularly made of spring sheet 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The invention is described below by way of example with reference to the figures, which show schematically Fig. 1 a sectional view of a first embodiment of a drive according to the invention with a volume compensation element with a rolling membrane, Fig. 2 a sectional view of the volume compensation element from 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 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 sectional detailed view of an exemplary alternative arrangement of the flow-dependent check valve from Fig. 7, Fig. 9 a sectional 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 from Fig. 9, Fig. 11 a sectional detailed view of a flow-dependent check valve with a sensor in a rest position and an end position, and Fig. 12 a perspective detailed view of the flow-dependent check valve from Fig. 11.

[0035] 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 11 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.

[0036] Fig. 2 shows the volume compensation element 19 from Fig. 1 in two different states, whereby the structural design is first explained using the upper illustration.

[0037] 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 a diaphragm base or base, and a flexed region 31, wherein the rolling diaphragm 21 has a material thickness at the head 30 that is greater than the material thickness of the flexed region 31.Furthermore, the rolling diaphragm 21 comprises an inner side 21a, which contacts the air 20, and an outer side 21b, with which the rolling diaphragm 21 rests against the inner wall of the differential housing 23, in particular the second housing shell 23b. The first housing shell 23a and the second housing shell 23b are connected to one another at a connection point 75, for example, welded, such that the oil 17 cannot penetrate into the differential housing 23 at the connection point 75. For this purpose, in this embodiment, the first housing shell 23a has a first sealing surface 35 and the second housing shell 23b has a second sealing surface 36 at the connection point 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 differential housing 23, in particular the second housing shell 23b, has an outflow opening 27 through which the oil 17 can basically 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.

[0038] The upper illustration in Fig. 2 shows the volume compensation element 19 in a state in which no oil 17 has yet flowed into the volume compensation element 19 through the outflow opening 27.

[0039] As the temperature of the oil 17 increases, it expands, causing its volume to increase. The lower illustration in Fig. Figure 2 shows the volume compensation element 19 in a state in which the oil 17 flows into the volume compensation element 19 through the outflow opening 27 upon an increase in the fluid temperature. The rolling diaphragm 21 performs a reciprocating movement 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 shown. At the same time, the volume of the air 20 held enclosed by the rolling diaphragm 21 in the compensation housing 23 decreases during the reciprocating movement of the rolling diaphragm 21. Thus, in the lower illustration, Fig. 2, the oil 17 flows through the discharge opening 27 into the volume compensation element 19 as the fluid temperature increases, compressing the air 20. Due to the stroke movement of the rolling diaphragm 21, an additional volume corresponding to the expansion of the oil 17 upon temperature increase is released for the oil 17, so that the pressure in the drive 11 does not increase.

[0040] If the fluid temperature decreases again, the volume of the oil 17 also decreases again. Due to the pressure ratio between the compressed air 20 on the one hand and the cooling oil 17 on the other hand, the rolling diaphragm 21 performs a stroke movement, during which the head 30 of the rolling diaphragm 21 in the lower illustration is in Fig. 2 is displaced linearly to the left. Thus, during this stroke movement, the oil 17 flows out of the volume compensation element 19 through the outflow opening 27 as the fluid temperature decreases, expanding the air 20.

[0041] During lifting movements of this embodiment, the flexed area 31 of the rolling diaphragm 21 rolls, forming a rolling fold 33 with the outer side 21b of the rolling diaphragm 21 against the inner wall of the compensation housing 23, in particular the second housing shell 23b. In general, the rolling diaphragm 21 does not experience any significant stretching due to the lifting movement of the rolling diaphragm 21, since the rolling diaphragm 21 is only slightly stressed due to the rolling, thereby increasing the reliability and functional safety of the drive 11. The rolling diaphragm 21 is designed for controlled rolling, in particular by the flexed area and the increased material thickness of the head 30. Other types of reinforcement of the head 30, for example by an incorporated fabric or a support element, are also conceivable.

[0042] If a fire occurs, the rolling diaphragm 21 performs a stroke movement due to the high temperatures typically associated with a fire, which exceeds the usual working stroke, for example, due to solar radiation. This way, an additional volume can be provided for the expanding oil 17 in the event of a fire, allowing the drive 11 to withstand even such high temperatures without leakage.

[0043] Fig. 3 shows the volume compensation element 19 of a second embodiment of a drive 11 according to the invention, wherein, in contrast to the volume compensation element 19 of Fig. 2 a rolling area 31 of the rolling membrane 21 rolls during a lifting movement, forming a rolling fold 33 with an inner side 21a of the rolling membrane 21 on an inner wall of the compensation housing 23, in particular the first housing shell 23a. In Fig. 3, two states are shown at the same time, namely a state in which no hydraulic fluid 17 flows into the volume compensation element 19, and a state in which the rolling diaphragm 21 carries out a lifting movement caused by the flowing hydraulic fluid 17, in which the head 30 of the rolling diaphragm 21 in the illustration according to Fig. 3 is shifted linearly to the right.

[0044] Fig. 4 shows the volume compensation element 19 of a third embodiment of a drive 11 according to the invention, in which, in contrast to the volume compensation element 19 of Fig. 3, a support element 93 is provided which is firmly connected, for example glued, to the head 30 of the rolling membrane 21. As in Fig. 3 are also in Fig. 4 simultaneously shows two states of the volume compensation element 19. Since the support element 93 supports a controlled rolling of the rolling membrane 21, the rolling membrane 21 at the head 30 does not have a material thickness that is greater than the material thickness of a flexed area 31 of the rolling membrane 21. In addition, the support element 93 can be supported on the compensation housing 23 in a linearly displaceable manner, which in Fig. 4 is not shown, however.

[0045] Fig. 5 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 from Fig. 2. The rolling membrane 21 of the volume compensation element 19 made of Fig. 5 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 membrane 21, in contrast to the one shown in Fig. 2 shown rolling membrane 21 made of a rubber elastomer, wherein in addition a Fig. 5 not shown fabric is incorporated into the rolling membrane 21.

[0046] Fig. 6 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, the hydraulic fluid 17 was accommodated in the drive housing 15 during manufacture of the drive 11 at a fluid temperature of, for example, 10°C. When the hydraulic fluid 17 is heated to the predefined temperature of 20°C, it then expands to such an extent that the gas 20 is partially compressed or pre-tensioned as a result of a lifting movement of the rolling diaphragm 21. 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 compensation element 19 through the outflow opening 27 with the gas 20 expanding, without a negative pressure being created 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 gas 20 prevents this, thus ensuring particularly reliable operation of the drive 11 over a wide temperature range, especially at low temperatures.

[0047] In addition to the temperature-related volume changes of the hydraulic fluid 17 described above, 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 hydraulic fluid 17. These operating pressures typically exhibit a high pressure increase within a short period of time and a high absolute value. However, they do not pose a threat to the drive mechanism 13 or the drive housing 15, but rather are necessary for a defined damping behavior and are closely interrelated with the damping behavior.In order to prevent the damping behavior from being disrupted by compression of the gas 20, on the one hand, and to protect the rolling diaphragm 21 from operationally increased pressures, on the other hand, the volume compensation element 19 can be provided with the compensation housing 23 comprising a closure element 25 which has a flow-dependent check valve 29. The flow-dependent check valve 29 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. The predetermined value is predetermined as a function of the operationally induced 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 17, whereby the back pressure increases with the flow velocity.

[0048] Fig. Figure 7 relates to a sixth embodiment of a drive 11 according to the invention, the compensation housing 23 of the volume compensation element 19 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 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.

[0049] 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. At low flow velocities, the hydraulic fluid 17 can thus flow past the ball 47a and through the outflow opening 27 into the volume compensation element 19. A dynamic pressure builds up on the ball 47a, which depends in particular on the flow velocity of the hydraulic fluid 17. Due to the dynamic 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.

[0050] 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.

[0051] 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 position, 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 to 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 apart 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. In the case of temperature-related volume changes of the hydraulic fluid 17, however, no or only insignificant dynamic pressures arise.

[0052] Fig. 8 relates to a seventh embodiment of a drive 11 according to the invention, the compensation housing 23 of the volume compensation element 19 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 functioning of the flow-dependent check valve 29 is analogous to the above-mentioned Fig. 7 described function. 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.

[0053] Fig. 9 relates to an eighth embodiment of a drive 11 according to the invention, the compensation housing 23 of the volume compensation element 19 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 fastened to the closure element 25 by a first section 51. Furthermore, 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.

[0054] 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, at low flow velocities, the hydraulic fluid 17 can flow past the flat part 49 and through 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.

[0055] 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 figure, 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 back pressures bend the flat part 49 into the final state. In the case of temperature-related volume changes of the hydraulic fluid 17, however, no or only insignificant back pressures arise.

[0056] 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.

[0057] Fig. 11 relates to a ninth embodiment of a drive 11 according to the invention, the compensation housing 23 of the volume compensation element 19 of which comprises an alternative closure element 25 with a flow-dependent check valve 29, wherein here too only a detailed view of the closure element 25 with the flow-dependent check valve 29 is shown. The closure element 25 has 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 and forms the sealing point.

[0058] 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, at low flow velocities, the hydraulic fluid 17 can flow past the sealing element 71 and through the outflow opening 27 into the volume compensation element 19. 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, bending the spring arms 59.In contrast, the transducer 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 transducer 55 can be displaced from its rest position.

[0059] 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 position, the sealing element 71 seals the support surface 43, whereby the flow-dependent check valve 29 closes the discharge 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 discharge 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, such that operational back pressures move the sensor 55 into the end position. In the case of temperature-related volume changes of the hydraulic fluid 17, however, no or only insignificant back pressures arise.

[0060] Fig. 12 shows that in Fig.11 shows the closure element 25 with the flow-dependent check valve 29 in a perspective detailed view, in which in particular the receiver 55 with the sealing element 71 and the design of the spring arms 59 are shown. List of reference symbols 11 Drive 13 Drive mechanism 15 drive housing 17 Hydraulic fluid 19 Volume compensation element 20 gas 21 Rolling diaphragm 21a Inside 21b Outside 23 differential housing 23a first housing shell 23b second housing shell 25 locking element 27 Outlet opening 29 flow-dependent check valve 30 heads 31 Walking area 33 roll fold 34 Sealing ring 35 first sealing surface 36 second sealing surface 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 junction point 77 Output shaft 79 pistons 81 compression spring 83 first end 85 second end 87 spindle 89 spindle plate 91 Room 93 Support element

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 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) flows into the volume compensation element (19) when the fluid temperature increases, compressing the gas (20), and flows out of the volume compensation element (19) when the fluid temperature decreases, expanding the gas (20), wherein a rolling diaphragm (21) is provided within the compensation housing (23), 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), executes a lifting movement caused by the flowing hydraulic fluid (17), during which a head (30) of the rolling diaphragm (21) is linearly displaced. [2] Drive (11) according to claim 1, characterized byin that the rolling diaphragm (21) comprises an inner side (21a) which at least partially contacts the gas (20), and an outer side (21b) with which the rolling diaphragm (21) at least partially bears against the inner wall of the compensation housing (23), and is designed in such a way that a rolling region (31) of the rolling diaphragm (21) rolls on the inner wall during the lifting movement, forming a rolling fold (33) with the outer side (21b) or with the inner side (21a). [3] Drive (11) according to one of the preceding claims, characterized by that the rolling membrane (21) on the head (30) has a material thickness which is increased compared to the material thickness of the rolling area (31). [4] Drive (11) according to one of the preceding claims, characterized by that a support element (93) is provided within the differential housing (23) and is firmly connected to the head (30), in particular wherein the support element (93) is supported on the differential housing (23) in a linearly displaceable manner. [5] Drive (11) according to one of the preceding claims, characterized by that the rolling membrane (21) comprises a sealing ring (34) with which the rolling membrane (21) is fastened, in particular injection-molded, to the compensation housing (23). [6] Drive (11) according to one of the preceding claims, characterized by in that the differential housing (23) comprises a first housing shell (23a) and a second housing shell (23b) which are connected to one another at a connecting point (75) in such a way that the hydraulic fluid (17) cannot penetrate into the differential housing (23) at the connecting point (75). [7] Drive (11) according to claim 5 and 6, characterized by 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 sealing 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 by that the rolling membrane (21) consists of a thermoplastic elastomer, preferably of a thermoplastic polyurethane, or of a rubber elastomer, and / or that a fabric is incorporated into the rolling membrane (21). [9] Drive (11) according to one of the preceding claims, characterized by that the amount of substance of the hydraulic fluid (17) is dimensioned such that at a hydraulic fluid temperature which corresponds to a predefined temperature, in particular of 20°C, the gas (20) 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 gas (20). [10] Drive according to one of the preceding claims, characterized byin that the compensation housing (23) comprises a closure element (25) which 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). [11] Drive (11) according to claim 10, characterized bythat 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) can be sealed, wherein a compressive force dependent on the dynamic pressure acts on the blocking element (47; 49; 55) and the blocking element (47; 49; 55) is subjected to a counterforce opposite to the compressive 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 (39; 41; 43), as a result of which 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) closes the sealing point (39; 41; 43), whereby the flow-dependent check valve (29) closes the outflow opening (27). [12] Drive (11) according to claim 11, 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 (39), 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. [13] Drive (11) according to claim 12, 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). [14] Drive (11) according to claim 13, characterized bythat the sealing point (39), in particular as a circular sealing edge (39), is formed on the tapered section (69) and the geometric body (47) is received in the first chamber (65) in such a way that the geometric body (47) is spaced apart from the sealing point (39) in the rest position, wherein the geometric body (47) is displaced into an end position in the case of a dynamic pressure above the predetermined value, in which end position the geometric body (47) seals the sealing point (39). [15] Drive (11) according to claim 11, 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 (41), wherein the restoring force of the flat part (49) provides the counterforce. [16] Drive (11) according to claim 15, characterized by that the sealing point (41) is designed to surround the outflow opening (27) in a planar manner, in particular as a circular projection (41), and the flat part (49) is fastened with a first section (51) to the closure element (25) in such a way that a second section (53) of the flat part (49) is spaced apart from the sealing point (41) 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 (41), [17] Drive (11) according to claim 11, 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). [18] Drive (11) according to claim 17, 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 (43), whereby the spring arms (59) are bent, the restoring force of the spring arms (59) providing the counterforce. [19] Drive (11) according to claim 17 or 18, 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 (43), wherein the support surface (43) of the closure element, on which the elastic sealing element (71) rests for sealing, forms the sealing point (43). [20] Drive (11) according to one of the preceding claims, characterized by that 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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