Gas pressure spring with temperature compensation and method for manufacturing a gas pressure spring

Abstract

The invention relates to a gas spring comprising a working piston which is movably guided in a working cylinder along a stroke axis in a stroke range, a compensation cylinder which surrounds the working cylinder radially with respect to the stroke axis, and a compensation piston which is movably guided in the compensation cylinder along the stroke axis. The working cylinder has an open end along the stroke axis, the compensation cylinder forms a protrusion beyond the working cylinder at the open end along the stroke axis, the protrusion having a closed end. The compensation piston separates a working chamber arranged in the working cylinder, a compensation chamber arranged between the working cylinder and the compensation cylinder, and a reset chamber arranged in the protrusion from one another. The distance of the compensation cylinder from the working cylinder, measured radially with respect to the stroke axis, is greater in the stroke range than in end regions of the working cylinder, which lie between the stroke range and the open end of the working cylinder.

Description

Technical Field

[0001] This invention relates to a gas spring, and to a method for manufacturing a gas spring. Background Technology

[0002] Gas springs are known in the prior art, in which the temperature dependence of the spring force is compensated by a compensating medium.

[0003] Patent document EP1795777A2 describes a gas spring with a working cylinder in which a working piston is slidably guided within the working cylinder. An annular space formed between the working cylinder and a compensating cylinder is filled with a compensating medium that expands upon temperature increase. The open end of the working cylinder opposite the piston outlet is closed by a cup-shaped compensating piston. As the compensating medium expands, it pushes the compensating piston to shift, thereby increasing the volume of the working cylinder.

[0004] Patent publication DE3141295A1 relates to a gas spring comprising a container, wherein a piston connected to a piston rod slides on the inner wall of the container. A space filled with an expanding material is located between a fixed partition of the container and a disc-shaped piston, which represents a movable partition for filling the space with the expanding material. The gas spring also includes a chamber filled with pressurized gas. When the temperature rises, the expanding material expands and causes the disc-shaped piston to move further away from the fixed partition of the container, thereby increasing the volume of the chamber.

[0005] Known gas springs with temperature compensation are typically complex in structure, require much more installation space than gas springs without temperature compensation, or cannot provide temperature-dependent compensation over the entire temperature range relevant to their application.

[0006] Technical tasks

[0007] The purpose of this invention is to design an economical and simple gas spring, and an economical and reliable method for manufacturing a gas spring, wherein the spring force of the gas spring is independent of temperature over the widest possible temperature range.

[0008] Technical solution

[0009] This invention provides a gas spring that solves the aforementioned technical problems. The object of this invention is also achieved through a method for manufacturing a gas spring.

[0010] The pneumatic spring includes a working piston that is movably guided within a working cylinder along a stroke axis within the stroke range. The working piston is preferably movable relative to the working cylinder along the stroke axis. The working cylinder is preferably shaped as a hollow cylinder and / or arranged coaxially with the stroke axis.

[0011] The gas spring includes a compensating cylinder that radially surrounds the working cylinder relative to the stroke axis. The compensating cylinder is preferably formed as a hollow cylinder and / or arranged coaxially with the stroke axis. The compensating cylinder is preferably rigidly attached to the working cylinder. The compensating cylinder is preferably integral, making the gas spring particularly easy to manufacture.

[0012] The working cylinder has an open end along the stroke axis. "Open" at least means that gas can freely escape from the working cylinder through the open end, and can also enter the working cylinder through the open end. Preferably, the open end is fully open.

[0013] At the piston rod end of the working cylinder, opposite the open end along the stroke axis, the piston rod, with a pneumatic spring attached to the working piston, is preferably led out of the working cylinder via a sealing device. The sealing device preferably seals the piston rod end relative to the gas. "Sealed" means that no gas escapes or enters the working cylinder at the piston rod end.

[0014] At the open end, the compensating cylinder forms a protrusion that extends beyond the working cylinder, and this protrusion has a closed end along the stroke axis.

[0015] At the piston rod end of the compensating cylinder, opposite the closed end along the stroke axis, the piston rod of the pneumatic spring is preferably led out of the compensating cylinder by a sealing device. The sealing device preferably seals the end of the piston rod relative to the gas.

[0016] The sealing device preferably seals the piston rod end of the compensating cylinder and the piston rod end of the working cylinder. The sealing device also preferably functions as a guide for guiding the piston rod along the stroke axis. The working cylinder is preferably attached to the compensating cylinder via the sealing device.

[0017] The sealing device may include a fastening element, preferably integrally formed, made of, for example, aluminum, which is attached to the compensating cylinder and the working cylinder, for example, by form-fitting and / or material-locking means, particularly by deformation of the compensating cylinder and / or the working cylinder. The sealing device may include multiple sealing elements (e.g., sealing rings) that seal the fastening element of the sealing device to the working cylinder, the compensating cylinder, and / or the piston rod.

[0018] The sealing device may include an outer portion that seals the piston rod end of the compensating cylinder and an inner portion that seals the piston rod end of the working cylinder. The advantage of this two-part structure is that the inner portion can be constructed like a standard pneumatic spring, eliminating the need for a compensating cylinder.

[0019] The external portion of the sealing device may include at least one external fastening element, such as a sleeve, which fastens the compensation cylinder to the working cylinder, for example by form-fit, force-locking, and / or material-locking. The external portion of the sealing device may include at least one external sealing element, such as a sealing ring, which seals the working cylinder to the compensation cylinder.

[0020] The internal portion of the sealing device may include at least one guide element (e.g., a guide bushing) that guides the piston rod along the stroke axis. The internal portion of the sealing device may also have at least one internal sealing element (e.g., a sealing ring) that seals the working cylinder to the piston rod.

[0021] A disc, particularly a metal disc with a corrosion-resistant surface, can be positioned between the piston rod end of the working cylinder and the piston rod end of the compensating cylinder. The disc increases the strength of the sealing device, especially preventing damage when the compensating cylinder is closed by the rollers. For example, the disc can be connected to an external fastening element of the sealing device via a latching connection.

[0022] The compensating piston preferably separates the working chamber arranged in the working cylinder, the compensating chamber arranged between the working cylinder and the compensating cylinder, and the reset chamber arranged in the protrusion in an airtight manner.

[0023] The compensation medium is preferably disposed in the compensation chamber, wherein when the compensation medium is heated, it causes the compensation piston to move toward the closed end. The pressure of the compensation medium is, for example, from 70 bar to 350 bar.

[0024] The compensating medium preferably comprises an expanding material, particularly an expanding wax, and especially preferably a mixture of expanding wax and oil. The compensating medium may consist, in particular, of an expanding material, an expanding wax, or a mixture of expanding wax and oil. The compensating medium may be designed, for example, similar to the compensating medium described in patent publication EP1795777A2. The expanding wax may be designed, for example, similar to the expanding wax described in patent application DE102020113749.

[0025] Preferably, the reset device is disposed in the reset chamber, wherein when the compensation medium cools, the reset device causes the compensation piston to move away from the closed end.

[0026] The reset device preferably includes or is a reset gas, which is preferably the same gas as the working gas filling the chamber. The reset gas and / or working gas is, for example, nitrogen. The reset device may include or be formed from a mechanical reset element, such as a spring, particularly a helical compression spring.

[0027] The working gas pressure is, for example, 20 bar to 250 bar. The reset gas pressure is, for example, 20 bar to 350 bar.

[0028] Preferably, for the distance between the compensation cylinder and the working cylinder, measured radially relative to the stroke axis, the distance within the stroke range is greater than the distance within the end region of the working cylinder located between the stroke range and the open end of the working cylinder.

[0029] The smaller distance in the end region results in a smaller cross-sectional area of ​​the compensation chamber perpendicular to the stroke axis in the end region. Therefore, at a given temperature rise, the compensation piston moves further towards the closed end of the compensation cylinder due to the expansion of the compensation medium, thereby allowing the working chamber to expand to a greater extent and better compensating for the temperature dependence of the gas spring force.

[0030] Since the distance within the stroke range is not reduced, the compensation chamber can still hold enough compensation medium to achieve effective temperature compensation.

[0031] The disadvantage of having different distances during the stroke and at the end of the stroke is that it complicates the manufacture of the gas spring. Furthermore, in the transition region between the stroke and the end of the stroke, material weakening may occur due to deformation of the working cylinder and / or the compensating cylinder, or leakage may occur due to the connection points between the components of the working cylinder and / or the compensating cylinder. Therefore, these different distances can jeopardize the reliable operation of the gas spring.

[0032] This distance is, for example, 10% to 50% smaller in the end region than in the stroke range, preferably 20% to 40% smaller, and particularly preferably 30% smaller. This distance is, for example, 1 mm to 8 mm in the end region, preferably 2 mm to 4 mm, and particularly preferably 2.5 mm. This distance is, for example, 2 mm to 12 mm in the stroke range, preferably 3 mm to 6 mm, and particularly preferably 3 mm to 3.5 mm. Using the above distance values, extensive, and particularly complete, compensation can be achieved for the temperature dependence of the gas spring force within the typical operating temperature range of the gas spring (e.g., from -10°C to +60°C).

[0033] Preferably, the distance of the compensating cylinder from the working cylinder in the end region and / or during the stroke is independent of its position along the stroke axis. In this embodiment, the distance in the end region and / or during the stroke is constant along the stroke axis, which means that the gas spring is particularly easy to manufacture. Detailed Implementation

[0034] In the end region of the working cylinder, the outer diameter of the end region of the working cylinder, measured radially relative to the stroke axis, is preferably larger than the outer diameter of the working cylinder within the stroke range, measured radially relative to the stroke axis. This expansion of the working cylinder in the end region results in a reduced distance between the working cylinder and the compensating cylinder without altering the shape of the compensating cylinder or the working cylinder within the stroke range. Therefore, compared to prior art pneumatic springs, a reduced distance is achieved with minimal alterations. Consequently, pneumatic springs can be manufactured particularly easily and economically, especially using known components and methods.

[0035] The outer diameter of the end region of the working cylinder is preferably 101% to 150% of the outer diameter of the working cylinder's stroke range, more preferably 105% to 130%, particularly preferably 110% to 120%, and most preferably 112% to 113%. The outer diameter of the end region is, for example, 15mm to 25mm, preferably 16mm to 22mm, and particularly preferably 18mm to 21mm. The outer diameter of the stroke range is, for example, 10mm to 20mm, preferably 15mm to 19mm, and particularly preferably 17mm to 18mm. Using the aforementioned outer diameter values, extensive compensation for the temperature dependence of the gas spring force can be achieved within the typical operating temperature range of the gas spring.

[0036] Preferably, the outer diameter of the working cylinder is independent of its position along the stroke axis in the end region and / or during the stroke. In this embodiment, the outer diameter is constant in the end region and / or along the stroke axis during the stroke, which makes the gas spring particularly easy to manufacture.

[0037] The inner diameter of the compensating cylinder, measured radially relative to the stroke axis, is preferably 110% to 200% of the outer diameter of the working cylinder within its stroke range, more preferably 140% to 170%, particularly preferably 150% to 160%, and most preferably 155% to 157%. The inner diameter of the compensating cylinder is, for example, 20 mm to 30 mm, preferably 23 mm to 27 mm, and particularly preferably 25 mm. Using the aforementioned value of the inner diameter of the compensating cylinder, extensive compensation for the temperature dependence of the spring force of the gas spring can be achieved within the typical operating temperature range of the gas spring.

[0038] Preferably, the inner diameter of the compensating cylinder is independent of its position along the stroke axis. In this embodiment, the inner diameter of the compensating cylinder is constant along the stroke axis, which makes the gas spring particularly easy to manufacture.

[0039] The stroke range and end region of the working cylinder are preferably connected in one piece to each other, making the gas spring particularly easy to manufacture. For example, the working cylinder can be widened relative to the stroke range in the end region transversely to the stroke axis.

[0040] The stroke range and end region can be connected to each other, for example, by material bonding, particularly by welding, soldering and / or gluing. The stroke range and end region can also be connected to each other, for example, by form-fitting and / or force-fitting, particularly by threaded connection, locking and / or clamping.

[0041] The working cylinder may include, for example, metal (especially steel) and / or plastic, or may be made of metal (especially steel) and / or plastic.

[0042] Preferably, the wall thickness of the working cylinder, measured radially relative to the stroke axis, is the same throughout the stroke and in the end region. The wall thickness should be considered the same, especially if it is the same except for a reduction in wall thickness due to expansion of the working cylinder in the end region (e.g., a reduction of at most 0.2 mm). The wall thickness is preferably independent of its position along the stroke axis. In this embodiment, the wall thickness of the working cylinder is constant along the stroke axis, which makes the gas spring particularly easy to manufacture.

[0043] The wall thickness of the compensating cylinder in the radial direction relative to the stroke axis is preferably independent of its position along the stroke axis. In this embodiment, the wall thickness of the compensating cylinder is constant along the stroke axis, which makes the gas spring particularly easy to manufacture.

[0044] The compensating piston is preferably integral, which makes the gas spring particularly easy to manufacture.

[0045] The compensating piston preferably comprises aluminum or plastic. The compensating piston is particularly preferably made of aluminum or plastic.

[0046] The compensating piston is preferably a hollow cylinder, and in particular, it is arranged coaxially with the stroke axis.

[0047] The compensating piston preferably has a cylinder seat on its lower side. The cylinder seat is preferably arranged perpendicular to the stroke axis and / or is closed.

[0048] The compensating piston preferably includes a cylinder liner arranged around the stroke axis. The cylinder liner is preferably closed.

[0049] The compensating piston is open on its upper side, opposite the cylinder seat, along the stroke axis. This allows the interior of the compensating piston to be used as part of the working chamber or reset chamber, enabling a particularly compact design for the gas spring.

[0050] The compensating piston is preferably cup-shaped, wherein the cylinder seat of the supplementary piston corresponds to the bottom of the cup, and the cylinder liner corresponds to the wall of the cup.

[0051] The advantage of hollow cylindrical or cup-shaped compensating pistons is that they can separate the working chamber, compensation chamber, and reset chamber with a very low mass.

[0052] Preferably, a compensating cylinder seal is arranged on the compensating piston, which seals the compensating piston to the compensating cylinder, particularly in an airtight manner. The compensating cylinder seal may be attached to the compensating piston. The compensating cylinder seal may include a sealing ring (particularly an O-ring), or may be formed from a sealing ring (particularly an O-ring) extending, in particular, coaxially around the stroke axis.

[0053] The compensating piston preferably includes a cylinder edge, which is preferably adjacent to the upper side, projecting radially outward from the stroke axis and extending beyond the cylinder liner. The compensating cylinder seal is arranged on, and particularly fastened to, the cylinder edge. By means of the cylinder edge, reliable sealing contact between the compensating cylinder seal and the compensating cylinder can be achieved with minimal material consumption.

[0054] The upper side of the compensating piston is preferably open to the reset chamber. As a result, the interior of the compensating piston becomes part of the reset chamber, allowing for a larger volume of the reset device relative to the working gas. Utilizing a smaller volume of working gas relative to the reset device volume makes it easier to compensate for the temperature dependence of the spring force.

[0055] Preferably, a working cylinder seal (particularly in a fastening manner) is arranged on the compensating piston, on the cylinder liner of the compensating piston, or on the working cylinder, which seals the compensating piston to the working cylinder, particularly in a hermetically tight manner. The working cylinder seal may comprise a sealing ring (particularly an O-ring), or may be formed of a sealing ring that extends coaxially, particularly, around the stroke axis.

[0056] The compensating piston, preferably the cylinder liner of the compensating piston, and particularly preferably the cylinder seat of the compensating piston, is preferably at least partially arranged in the end region of the working cylinder. As a result, the volume of the compensating chamber and / or the reset chamber is increased relative to the volume of the working chamber, thereby achieving more effective compensation for the temperature dependence of the spring force of the pneumatic spring.

[0057] The compensating piston is preferably arranged entirely within the compensating cylinder. This has the advantage that the length of the pneumatic spring, measured along the stroke axis, does not change as the compensating piston moves. Therefore, the length of the pneumatic spring is independent of temperature.

[0058] The pneumatic spring preferably includes multiple support elements, such as one, two, three, four, five or more support elements, which support the working cylinder on the compensating cylinder. The support elements advantageously prevent relative movement of the working cylinder relative to the compensating cylinder, which could weaken the seal between the compensating piston and the working cylinder or the compensating cylinder, or affect the displaceability of the compensating piston along the stroke axis.

[0059] The support elements are preferably arranged spaced apart from each other around the stroke axis, and / or the support elements preferably have openings along the stroke axis. As a result, the support elements do not substantially impede the expansion or compression of the compensation medium in the compensation chamber between the working cylinder and the compensation cylinder along the stroke axis.

[0060] The support elements are preferably evenly distributed around the stroke axis. This allows the support elements to reliably support the working cylinder on the compensating cylinder.

[0061] The support element is preferably located at the end region of the working cylinder. Since the end region is adjacent to the compensating piston, the support element can particularly effectively ensure the sealing and displacement of the compensating piston at the end region.

[0062] The support element can be designed as a ring with a perforation along the stroke axis, arranged coaxially with the stroke axis and mechanically connecting the working cylinder to the compensating cylinder. This ring is preferably positioned within the stroke range of the working cylinder. Within the stroke range, the ring provides minimal resistance to the expansion or compression of the compensating medium in the compensating chamber along the stroke axis.

[0063] Preferably, multiple support elements are integrally formed with the working cylinder or compensation cylinder. This reduces the number of parts in the gas spring, making it particularly easy, quick, and economical to manufacture gas springs.

[0064] Support elements can be formed, for example, by reshaping the working cylinder and / or the compensating cylinder. This allows the support elements to be formed particularly quickly and easily. Deformations include, for example, widening of the working cylinder on the compensating cylinder and / or, particularly, dotted indentations of the compensating cylinder on the working cylinder. Because the distance between the working cylinder and the compensating cylinder is small in the end region, the support element can be formed particularly easily in the end region by such deformation.

[0065] A method for manufacturing a gas spring preferably includes providing a working cylinder blank, wherein the working cylinder blank is formed as a hollow cylinder and has an outer diameter transverse to the longitudinal axis, the outer diameter being independent of its position along the longitudinal axis of the working cylinder blank. Therefore, the outer diameter is constant along the stroke axis. The working cylinder blank can, in particular, be the working cylinder of a known gas spring. The working cylinder blank preferably has material properties that depend on its azimuth relative to its longitudinal axis, which is caused, for example, by welds along the longitudinal axis. Such a working cylinder blank can be manufactured particularly easily and economically, for example, by drawing and welding steel.

[0066] The method preferably includes forming a working cylinder blank into a working cylinder of a pneumatic spring, the forming including expanding the outer diameter of the working cylinder blank in the end region of the working cylinder blank.

[0067] The method preferably includes arranging the compensating piston of the pneumatic spring at least partially in the end region of the working cylinder of the pneumatic spring.

[0068] The expansion preferably involves inserting a mandrel into the end region, and preferably, prior to inserting the mandrel, a sleeve extending about the longitudinal axis is provided around the end region of the working cylinder blank, such that the end region abuts against the sleeve after expansion. This advantageously allows the diameter of the working cylinder blank to expand to a diameter independent of the azimuth angle, the material properties of which depend on the azimuth angle relative to its longitudinal axis.

[0069] The method preferably involves reshaping the working cylinder and / or the compensating cylinder of the pneumatic spring to produce multiple support elements that support the working cylinder on the compensating cylinder. The support elements can be designed as described above, thereby producing the advantages mentioned above.

[0070] The forming process for producing the support element includes, for example, widening the working cylinder to the compensation cylinder and / or deepening the compensation cylinder to the working cylinder, particularly widening or deepening it in a point-like manner.

[0071] Particularly preferably, the expansion of the working cylinder to generate a support element and the expansion of the end region of the working cylinder blank to form the working cylinder are performed in the same step. For this purpose, for example, a mandrel can be inserted into the end region of the working cylinder blank, the mandrel preferably having multiple protrusions to generate a support element during the expansion of the end region of the working cylinder blank to form the working cylinder.

[0072] The method preferably includes forming or machining a compensating piston blank into a compensating piston. Forming allows for the manufacture of the compensating piston with particularly low material requirements. The compensating piston can be manufactured, for example, by deep drawing a compensating piston blank made of aluminum. The compensating piston can also be manufactured, for example, by forming a compensating piston blank made of steel.

[0073] The compensating piston blank can, for example, have a hollow cylindrical shape. The hollow cylindrical compensating piston blank can be expanded at one end along its longitudinal axis, for example, from an inner diameter of 18 mm to an inner diameter of 23 mm, thereby forming an outwardly projecting cylinder edge. The hollow cylindrical compensating piston blank can be closed at its other end by roller sealing and / or plasma welding to form a closed cylinder seat. Wavy grooves extending around its longitudinal axis can be rolled into the cylinder liner of the compensating cylinder blank to partially accommodate the compensating cylinder seal and / or the working cylinder seal.

[0074] Preferably, the working cylinder of the pneumatic spring has a groove on the inner side of the cylinder sleeve, through which the gas in the working cylinder can flow along the stroke axis of the pneumatic spring through the groove to the working piston of the pneumatic spring.

[0075] The cross-sectional area of ​​the groove orthogonal to the stroke axis preferably varies along the stroke axis. Preferably, this cross-sectional area is smallest at the ends of the stroke range of the working cylinder and largest in the central portion between the ends of the stroke range. This results in higher flow resistance to the gas at the ends of the stroke range. Therefore, compared to the middle position of the piston rod, the pneumatic spring generates higher damping force near the maximum insertion position of the piston rod into the pneumatic spring and near the maximum extension position of the piston rod from the pneumatic spring. The increased damping force near the maximum insertion and maximum extension positions causes the movement of the piston rod to be more strongly braked at these positions, thereby preventing damage to the pneumatic spring due to high-speed reaching of the maximum insertion or maximum extension positions.

[0076] The cross-sectional area of ​​the groove preferably varies with the variable depth of the groove perpendicular to the inner side of the sleeve wall of the working cylinder.

[0077] In a particularly advantageous embodiment, especially for use in the drive system described below, the cross-sectional area of ​​the groove in the extended transition region increases (preferably linearly) along the stroke axis from the extended end of the stroke range of the working cylinder (towards the piston rod end of the working cylinder) towards the open end of the working cylinder; in the central region adjacent to the extended transition region, the cross-sectional area of ​​the groove remains constant; in the insertion transition region adjacent to the central region, the cross-sectional area of ​​the groove decreases (preferably linearly); and in the insertion end region adjacent to the insertion transition region, the depth of the groove remains constant, the insertion end region extending to the insertion end of the stroke range towards the open end of the working cylinder.

[0078] Due to the aforementioned orientation of the cross-sectional area, high damping force is achieved when the piston rod is inserted into the pneumatic spring and approaches its maximum insertion point. This in particular prevents the pneumatically spring-supported baffle from closing too quickly, which could otherwise damage the baffle or injure the baffle operator.

[0079] The working piston of the pneumatic spring preferably includes a seal, particularly a sealing ring, that seals the piston to the interior of the sleeve wall of the working cylinder. The seal is preferably rigid so that it does not seep into the grooves arranged on the inner side of the sleeve wall. This prevents the seal from closing the grooves, which would otherwise clog the pneumatic spring.

[0080] This invention relates to a drive system for a baffle, the baffle having

[0081] a. A pneumatic spring according to the invention for supporting a baffle, and

[0082] b. Electromechanical drives used to drive baffles, such as linear drives, especially spindle drives.

[0083] The baffle could be, for example, a vehicle baffle, particularly an engine hood, trunk lid, luggage compartment cover, or wing door.

[0084] A drive system for the baffle is known in the prior art, which has a pneumatic spring for supporting the baffle and an electromechanical actuator for driving the baffle. Except for using a pneumatic spring according to the invention instead of a conventional pneumatic spring, the drive system according to the invention can be constructed in the same manner as the corresponding drive systems in the prior art, such as DE 103 13440A1 or DE 10 2008 045903 A1.

[0085] The gas spring of the drive system is used to hold the baffle in any position against gravity, while the electromechanical actuator is used to open and close the baffle. Alternatively, manual actuation of the baffle can be provided as in DE 103 13 440A1 and DE 10 2008 045 903 A1.

[0086] Gas springs must possess a high spring force to maintain the baffle even at low ambient temperatures. Since the spring force in traditional gas springs increases with temperature, this means that at high temperatures, the electromechanical actuator or operator must apply a very large force to close the baffle. Therefore, the drive system must include a very powerful electromechanical actuator, which is expensive, takes up a lot of space, and consumes a significant amount of energy during operation. Furthermore, the electromechanical actuator and other components mechanically connected to the baffle (such as hinges) also experience significant wear.

[0087] In the prior art, these problems are avoided by using spring struts instead of gas springs (e.g., DE 102008045 903A1, paragraph

[0021] ). Although the spring force of a spring strut is almost independent of temperature, it is larger, heavier, and more expensive than a gas strut with a comparable spring force.

[0088] Compared to a spring strut designed to support a given load, a pneumatic spring designed to support the same load has a higher damping force due to its higher air pressure. This is especially true at high insertion speeds, as the fluid dynamics of the gas in the pneumatic spring increase with the insertion speed of the piston rod into the spring. As a result, the pneumatic spring only slightly slows down the slow movement of the baffle that occurs when the baffle operates as intended by the actuator. For example, if the baffle operates incorrectly or the actuator malfunctions, rapid movement of the baffle may occur, and the pneumatic spring will slow down significantly.

[0089] This means that the drive system is particularly lightweight, cost-effective, space-saving, and safe due to the use of a gas spring instead of a spring strut. The aforementioned disadvantages of standard gas springs are overcome by using a temperature-compensated gas spring according to the invention instead of a standard gas spring. Attached Figure Description

[0090] Figure 1 shows an example of a schematic longitudinal section along the stroke axis of an embodiment of a gas spring according to the present invention.

[0091] Figure 2 shows a schematic longitudinal section of an alternative embodiment of the sealing device of the gas spring according to the present invention.

[0092] Figure 3 schematically illustrates the variation in the groove depth on the inner side of the sleeve wall of the working cylinder of the pneumatic spring according to the present invention.

[0093] Figure 1

[0094] Figure 1 shows a schematic longitudinal section along the stroke axis H of an embodiment of the gas spring 50 according to the present invention.

[0095] The pneumatic spring 50 shown includes a working piston 2, a compensating cylinder 12, and a hollow cylindrical compensating piston 10. The working piston 2 is movably guided in the working cylinder 1 along the stroke axis H within the stroke range HB. The compensating cylinder 12 is radially surrounding the working cylinder 1 relative to the stroke axis H. The hollow cylindrical compensating piston 10 is movably guided in the compensating cylinder 12 along the stroke axis H relative to the working cylinder 1 and the compensating cylinder 12.

[0096] The working cylinder 1 has an open end 1b along the stroke axis H, and the compensation cylinder 12 forms a protrusion 15 above the working cylinder 1 at the open end 1b, the protrusion having a closed end 15b along the stroke axis H.

[0097] The compensation piston 10 separates the working chamber 1a located in the working cylinder 1, the compensation chamber 12a located between the working cylinder 1 and the compensation cylinder 12, and the reset chamber 15a located in the protrusion 15 from each other.

[0098] The compensating piston 10 includes a cylinder seat 10b located on the lower side of the compensating piston 10 facing the working chamber 1a and a cylinder liner 10c arranged around the stroke axis H. A portion of the cylinder seat 10b and the cylinder liner 10c are arranged in the working cylinder 1a. The compensating piston 10 has an opening on the upper side 10a facing the reset chamber 15a.

[0099] The compensation piston 10 is provided with a compensation cylinder seal 8, which seals the compensation piston 10 and the compensation cylinder 12.

[0100] The compensating piston 10 includes a cylinder edge 10d that protrudes radially outward from the cylinder liner 10c relative to the stroke axis H, and a compensating cylinder seal 8 is arranged on the cylinder edge 10d.

[0101] The cylinder liner 10c of the compensating piston 10 is provided with a working cylinder seal 18, which seals the compensating piston 10 with the working cylinder 1.

[0102] At the piston rod end 1c of the working cylinder 1, which is opposite to the open end 1b along the stroke axis H, the piston rod 6, which is attached to the working piston 2, is led out from the working cylinder 1 through the sealing device 20.

[0103] The sealing device 20 includes, for example, a fastening element 21 made of integral aluminum, which is fixed to the compensation cylinder 12 and the working cylinder 1 in a form-fit manner. The sealing device 20 includes a plurality of sealing elements 22 (e.g., four sealing rings) that seal the fastening element 21 of the sealing device 20 to the working cylinder 1, the compensation cylinder 12 and the piston rod 6.

[0104] The distance between the compensation cylinder 12 and the working cylinder 1, measured radially relative to the stroke axis H, is greater in the stroke range HB than in the end region EB of the working cylinder 1, which is located between the stroke range HB and the open end 1b of the working cylinder 1.

[0105] The decrease in distance in the end region EB is because the outer diameter EAD of the end region of working cylinder 1 (measured radially relative to the stroke axis H) is larger than the outer diameter HAD of the stroke range of working cylinder 1 in the stroke range HB (measured radially relative to the stroke axis H). The outer diameter EAD of the end region is, for example, 18 mm to 20 mm. The outer diameter HAD of the end range is, for example, 16 mm.

[0106] The inner diameter AID of the compensation cylinder 12 is, for example, 25 mm.

[0107] Figure 2

[0108] Figure 2 shows a schematic longitudinal section along the stroke axis H of an alternative embodiment of the sealing device 20 of the gas spring 5 according to the invention.

[0109] The sealing device 20 shown in Figure 2 includes the outer portion of the piston rod end 12c of the sealing compensation cylinder 12 and the inner portion of the piston rod end 1c of the sealing working cylinder 1.

[0110] The outer portion of the sealing device 20 includes an external fastening element 23 (e.g., a sleeve) that fastens the compensation cylinder 12 to the working cylinder 1, for example, by a material bond, particularly by an adhesive. The outer portion of the sealing device also includes an external sealing element 24 (e.g., a sealing ring) that seals the working cylinder 1 to the compensation cylinder 12.

[0111] The internal portion of the sealing device 20 includes a guide element 26 (e.g., a guide bushing) that guides the piston rod 6 of the pneumatic spring 5 along the stroke axis H. The internal portion of the sealing device 20 includes at least one internal sealing element 27 (e.g., one or two sealing rings) that seals the working cylinder 1 to the piston rod 6.

[0112] For example, a disc 25 (especially a metal disc with a corrosion-resistant surface) is arranged between the piston rod end 1c of the working cylinder 1 and the piston rod end 12c of the compensation cylinder 12.

[0113] Figure 3

[0114] Figure 3 schematically shows the variation of the groove depth d on the inner side of the sleeve wall of the working cylinder of the pneumatic spring according to the invention at position x along the stroke axis of the pneumatic spring.

[0115] In the example shown, in the extended transition region AUB, the depth of the groove increases linearly along the stroke axis from the extended end AE of the stroke range of the working cylinder (facing the piston rod end of the working cylinder) towards the open end of the working cylinder; in the central region ZB adjacent to the extended transition region AUB, the depth of the groove remains constant; in the insertion transition region EUB adjacent to the central region ZB, the depth of the groove decreases linearly; and in the insertion end region EEB adjacent to the insertion transition region EUB, the depth of the groove remains constant, which extends to the insertion end EE of the stroke range facing the open end of the working cylinder.

[0116] List of reference numerals

[0117] 1 Working cylinder 23 External fastening components

[0118] 1a Internal chamber 24 External sealing element

[0119] 1b Open End 25 Plates

[0120] 1c piston rod end 26 guide element

[0121] 2 Working piston 27 Internal sealing element

[0122] 6 piston rod 50 gas spring

[0123] 8. Compensation cylinder seals

[0124] 10 Compensating Piston AE Extension End

[0125] 10b cylinder seat AID compensated cylinder bore

[0126] 10c cylinder liner AUB extended transition area

[0127] 10d cylinder block edge d depth

[0128] 12 Compensation Cylinder EAD End Region Outer Diameter

[0129] 12a Compensation Chamber EB Terminal Region

[0130] 12c piston rod end EE insertion end

[0131] 15. Protrusion EEB Insertion End Region

[0132] 15a Reset Chamber EUB Insertion Transition Area

[0133] 15b Closed-end H-stroke axis

[0134] 18 Working Cylinder Seal HAD Stroke Range Outer Diameter

[0135] 20 sealing device HB stroke range

[0136] 21. Position of fastening element x along the stroke axis

[0137] 22 Sealing element ZB central area

Claims

1. A gas spring (50), comprising a. A working piston (2), which is movably guided within the working cylinder (1) along the stroke axis (H) within the stroke range (HB), b. A compensating cylinder (12), which radially surrounds the working cylinder (1) relative to the stroke axis (H), and c. A compensating piston (10), which is movably guided along the stroke axis (H) in a compensating cylinder (12), d. Among them, the working cylinder (1) has an open end (1b) along the stroke axis (H). e. Among them, The compensation cylinder (12) forms a protrusion (15) extending beyond the working cylinder (1) along the stroke axis (H) at the open end (1b), the protrusion (15) having a closed end (15b). f. Wherein, the compensation piston (10) separates the working chamber (1a) in the working cylinder (1), the compensation chamber (12a) between the working cylinder (1) and the compensation cylinder (12), and the reset chamber (15a) in the protrusion (15) from each other. g. Wherein, for the distance between the compensation cylinder (12) and the working cylinder (1) measured radially relative to the stroke axis (H), the distance in the stroke range (HB) is greater than the distance in the end region (EB) of the working cylinder (1), the end region (EB) being located between the stroke range (HB) and the open end (1b) of the working cylinder (1), Its features are, h. The compensating piston (10) is arranged at least partially in the end region (EB) of the working cylinder (1).

2. The gas spring (50) according to claim 1, characterized in that, The wall thickness (WS) of the working cylinder (1) measured radially relative to the stroke axis (H) is the same in the stroke range (HB) and in the end region (EB) of the working cylinder (1).

3. The gas spring (50) according to any one of claims 1 to 2, characterized in that, The compensation piston (10) is a single piece.

4. The gas spring (50) according to claim 1, characterized in that, The compensation piston (10) may be made of aluminum or plastic.

5. The gas spring (50) according to claim 1, characterized in that, The compensating piston (10) is a hollow cylinder, wherein the compensating piston (10) a. Includes a closed cylinder seat (10b) located below the compensating piston (10). b. Including cylinder liners (10c) arranged around the stroke axis (H), and c. An opening is made on the upper side of the compensating piston (10), the upper side being arranged opposite the cylinder seat (10b) along the stroke axis (H). d. The compensation piston (10) is provided with a compensation cylinder seal (8), which seals the compensation piston (10) to the compensation cylinder (12).

6. The gas spring (50) according to claim 5, characterized in that, a. The compensating piston (10) includes a cylinder edge (10d) that projects radially outward on the cylinder liner (10c) relative to the stroke axis (H). b. Among them, The compensating cylinder seal (8) is located on the edge (10d) of the cylinder body.

7. The gas spring (50) according to any one of claims 5 to 6, characterized in that, The upper side reset chamber (15a) of the compensation piston (10) is opened.

8. The gas spring (50) according to claim 1, characterized in that, The compensating piston (10) is provided with a working cylinder seal (18), which seals the compensating piston (10) to the working cylinder (1).

9. The gas spring (50) according to claim 1, characterized in that, The pneumatic spring (50) includes multiple support elements that support the working cylinder (1) on the compensation cylinder (12).

10. The gas spring (50) according to claim 9, characterized in that, The plurality of support elements are integrally formed with the working cylinder (1) or the compensation cylinder (12).

11. The gas spring (50) according to claim 1, characterized in that, The compensating piston (10) is fully arranged in the compensating cylinder (12).

12. A method for manufacturing a gas spring (50) according to any one of claims 1 to 11, characterized by the following steps: a. A working cylinder blank is provided, wherein the working cylinder blank is in the shape of a hollow cylinder and has an outer diameter transverse to its longitudinal axis, the outer diameter being independent of its position along the longitudinal axis. b. Forming the working cylinder blank into a working cylinder (1) of a pneumatic spring (50), the forming comprising expanding the outer diameter of the working cylinder blank in the end region of the working cylinder blank, and c. Arrange the compensation piston (10) of the pneumatic spring (50) at least partially in the end region (EB) of the working cylinder (1) of the pneumatic spring (50).

13. The method according to claim 12, characterized in that, The expansion includes inserting a mandrel into the end region, and prior to inserting the mandrel, providing a sleeve extending about a longitudinal axis around the end region such that the end region abuts against the sleeve after expansion.

14. The method according to claim 13, characterized by the following steps: The working cylinder (1) of the pneumatic spring (50) and / or the compensation cylinder (12) of the pneumatic spring (50) are formed to produce a plurality of support elements that support the working cylinder (1) on the compensation cylinder (12).

15. A drive system for a baffle, comprising: a. The gas spring (50) according to any one of claims 1 to 11, wherein the gas spring (50) is used to support the baffle, and b. An electromechanical drive device for driving the baffle.

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