Gas spring with temperature compensation, method for manufacturing the gas spring

Description

Technical field

[0001] The invention relates to a gas spring according to the preamble of claim 1 and a method for manufacturing the gas spring. State of the art

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

[0003] The publication EP 1 795 777 A2 describes a gas spring with a working cylinder in which a working piston is slidably guided. The annular space formed between the working cylinder and a compensating cylinder is filled with a compensating medium that expands when the temperature rises. The open end of the working cylinder opposite the piston exit end is closed by means of a cup-shaped compensating piston. When the compensating medium expands, it displaces the compensating piston, thus increasing the volume of the working cylinder.

[0004] German patent application DE 31 41 295 A1 relates to a gas spring consisting of a container along whose inner wall a piston connected to the piston rod slides. A chamber filled with an expansion material is located between a fixed partition wall of the container and a disc piston, this disc piston forming a movable partition for the expansion material-filled chamber. The gas spring further comprises a working chamber containing pressurized gas. When the temperature increases, the expansion material expands, causing the disc piston to move further away from the fixed partition wall, thereby enlarging the working chamber.

[0005] Known gas springs with temperature compensation are usually complex in design, require significantly more installation space than gas springs without temperature compensation, or cannot compensate for the temperature dependence over the entire application-relevant temperature range. Technical task

[0006] The object of the invention is to create a cost-effective and simply constructed gas spring and a cost-effective and reliable method for its manufacture, wherein the spring force of the gas spring is independent of the temperature over the widest possible temperature range. Technical solution

[0007] The present invention provides a gas spring according to claim 1, which solves the technical problem. The problem is also solved by a method for manufacturing the gas spring according to claim 13. Advantageous embodiments are described in the dependent claims.

[0008] The gas spring comprises a working piston slidably guided within a working cylinder along a stroke axis over a stroke range. The working piston is preferably slidable relative to the working cylinder along the stroke axis. The working cylinder is preferably hollow cylindrical and / or arranged coaxially to the stroke axis.

[0009] The gas spring comprises a compensating cylinder that surrounds the working cylinder radially to the stroke axis. The compensating cylinder is preferably hollow and / or arranged coaxially to the stroke axis. The compensating cylinder is preferably rigidly attached to the working cylinder.

[0010] The gas spring comprises a hollow cylindrical compensating piston that is slidably guided within the compensating cylinder along the stroke axis. The compensating piston is preferably arranged coaxially with the stroke axis. The compensating piston is preferably slidable relative to both the compensating cylinder and the working cylinder along the stroke axis.

[0011] The working cylinder has an open end along the stroke axis. "Open" means at least that gas can escape from and enter the working cylinder unhindered through the open end. Preferably, the open end is completely open.

[0012] At the piston rod end of the working cylinder, opposite the open end along the stroke axis, a piston rod attached to the working piston is preferably guided out of the working cylinder through a sealing device. The sealing device preferably closes the piston rod end to a gas. "Closed" means that no gas can escape from or enter the working cylinder at the piston rod end.

[0013] According to an embodiment of the working cylinder that is advantageous for gas springs of the generic type, even independently of the other features of the invention, the working cylinder preferably has a sealing area outer diameter, measured radially to the stroke axis, in a sealing area between the stroke area and the piston rod end of the working cylinder where the piston rod exits the working cylinder. This outer diameter is larger than the stroke area outer diameter of the working cylinder. The sealing area outer diameter is, for example, 18 mm to 21 mm and is preferably constant over the sealing area.

[0014] Due to the enlarged outer diameter of the sealing area, even with a large piston rod diameter of, for example, 10 mm, the sealing device can be positioned and held within the working cylinder, and in particular, completely within the working cylinder. This eliminates the need for a separate retaining element to hold the sealing device. The retaining element could, for example, be a sleeve inserted into the piston rod end of the working cylinder, especially an aluminum sleeve. Consequently, the gas spring is particularly easy and cost-effective to manufacture.

[0015] The compensating cylinder forms a projection at its open end over the working cylinder, with a closed end along the stroke axis.

[0016] At the piston rod end of the compensating cylinder opposite the closed end along the stroke axis, the piston rod of the gas spring is preferably guided out of the compensating cylinder by a sealing device. The sealing device preferably closes the piston rod end to the gas.

[0017] The compensating piston separates a working chamber arranged in the working cylinder, a compensating chamber arranged between the working cylinder and the compensating cylinder, and a return chamber arranged in the projection, preferably gas-tight, from each other.

[0018] The compensating piston preferably has a cylinder base on its underside facing the return chamber. The cylinder base is preferably oriented perpendicular to the stroke axis and / or closed.

[0019] The compensating piston preferably comprises a cylinder jacket arranged section by section between the working cylinder and the compensating cylinder. The cylinder jacket preferably rotates around the stroke axis and / or is closed. Arranging the cylinder jacket section by section between the working cylinder and the compensating cylinder has the advantage of reducing the overall length of the gas spring.

[0020] The compensating piston is open on its upper side, facing the working chamber. This offers the advantage that the interior of the compensating piston serves as part of the working chamber, resulting in a particularly compact gas spring design.

[0021] The compensating piston is preferably pot-shaped, with the cylinder bottom corresponding to a pot bottom and the cylinder shell to a pot wall.

[0022] A hollow cylindrical or pot-shaped compensating piston has the advantage that it can separate the working space, the compensation space and the return space from each other with a particularly low material requirement.

[0023] Preferably, a compensating medium is arranged in the compensating chamber, which moves the compensating piston towards the closed end when the compensating medium is heated.

[0024] The compensating medium preferably comprises an extensible material, in particular an extensible wax, and most preferably a mixture of an extensible wax and an oil. The compensating medium can, in particular, consist of the extensible material, the extensible wax, or the mixture of extensible wax and oil. The compensating medium can, for example, be designed as described in EP 1 795 777 A2. The extensible wax can, for example, be designed as described in DE 10 2020 113 749. The pressure of the compensating medium is, for example, from 70 bar to 350 bar.

[0025] Preferably, a restoring means is arranged in the restoring chamber, which moves the compensating piston away from the closed end when the compensating medium cools down.

[0026] The restoring means comprises, or preferably is, a restoring gas, wherein the restoring gas is preferably the same gas that fills the working chamber as the working gas. The restoring gas and / or the working gas is, for example, nitrogen. The restoring means may comprise, or be formed from, a mechanical restoring element, for example, a spring, in particular a helical compression spring.

[0027] The working gas pressure, for example, ranges from 20 bar to 250 bar. The return gas pressure, for example, ranges from 20 bar to 350 bar.

[0028] The gas spring comprises a seal, in particular exactly one, arranged on, in particular on, the top of the compensating piston, preferably displaceable with the compensating piston along the stroke axis, which seals the compensating piston to the working cylinder and to the compensating cylinder, in particular sealing gas-tight.

[0029] In previously known gas springs with temperature compensation, for example according to EP 1 795 777 A2, at least two seals are necessary to seal a compensating piston to a working cylinder and a compensating cylinder. The sealing of the working cylinder and compensating cylinder with a single seal according to the invention leads to a significantly simpler and more cost-effective manufacture of the gas spring and reduces potential leakage points, thus enabling reliable operation of the gas spring over a long service life.

[0030] For the seal to be able to seal both the working cylinder and the compensating cylinder, it must be located on the top of the compensating cylinder. Based on the prior art, arranging the seal on the top of the compensating piston does not appear promising because only a narrow contact area is available on the open top surface to attach the seal to the compensating piston.

[0031] However, tests have surprisingly shown that it is not necessary to attach the seal to the compensating piston. In fact, during operation of the gas spring, the pressure of the compensating medium presses the seal firmly enough against the compensating piston to reliably fulfill its sealing function.

[0032] Advantageously, the seal is not attached to the compensating piston, and in particular neither to the compensating piston nor to the compensating cylinder or the working cylinder. This allows the gas spring to be manufactured particularly simply and cost-effectively. Description of the execution types

[0033] The compensating piston is preferably sealed exclusively by the seal between the working cylinder and the compensating cylinder. The gas spring therefore includes no further seals between the working cylinder, compensating piston, and compensating cylinder, and is thus of a particularly simple design. The seal is preferably a single piece.

[0034] The seal preferably comprises a sealing ring, for example an O-ring, that rotates around the stroke axis. A sealing ring that rotates around the stroke axis is particularly preferred.

[0035] The seal preferably comprises or consists of polyurethane and / or acrylonitrile butadiene rubber. Acrylonitrile butadiene rubber has the particular advantage that only low frictional forces occur between the seal and the compensating cylinder.

[0036] The compensating piston is preferably a single piece and can be obtained, for example, by forming it from a compensating piston blank. A one-piece compensating piston has the advantages that the manufacturing of the gas spring is simplified and that the compensating piston contains no joints that could cause leaks.

[0037] The compensating piston preferably comprises or consists of aluminum or a plastic. A particularly lightweight and cost-effective compensating piston can be manufactured from these materials. Due to the shape and arrangement of the compensating piston according to the invention, it remains stable even when using these materials, despite the high pressures prevailing in the gas spring.

[0038] The gas spring preferably comprises a guide element that slidably guides the compensating piston relative to the compensating cylinder along the stroke axis. The guide element preferably comprises a guide sleeve arranged in the projection between the compensating cylinder and the compensating piston, particularly coaxially to the stroke axis. The guide element can be attached to the compensating piston or the compensating cylinder. For example, the guide element can be integral with the compensating piston or the compensating cylinder. The guide element can, for example, comprise a guide ring, particularly made of plastic, which can be attached to the compensating piston, particularly by a snap-fit ​​connection. The guide element advantageously prevents the compensating piston from tilting relative to the working cylinder and the compensating cylinder. Tilting could impair the sealing function of the seal on the compensating piston.

[0039] The compensating piston preferably comprises a cylinder flange, preferably adjacent to the top surface and projecting radially beyond the cylinder shell to the stroke axis, with the seal being arranged on the cylinder flange. The cylinder flange provides an enlarged contact area between the seal and the compensating piston, thus ensuring particularly reliable sealing performance. Furthermore, the seal can be more reliably moved along the stroke axis together with the compensating piston and, if necessary, attached to the compensating piston.

[0040] Preferably, the cylinder rim projects radially outwards beyond the cylinder shell. This creates a gap between the cylinder shell and the compensating cylinder, open to the return chamber, which is available to the return element, thus increasing the return chamber for a given overall length. The resulting lower pressure of the return element makes the gas spring easier to seal. To prevent the compensating piston from tilting in the compensating cylinder despite the radially outward projection of the cylinder rim, the gas spring in this configuration preferably includes the guide element described above. The guide element is preferably attached to the compensating piston or integrally formed with it, so that the guide element and the cylinder rim do not interfere with each other.

[0041] A distance of the compensating cylinder from the working cylinder, measured radially to the stroke axis, is preferably greater in the stroke range than in an end region of the working cylinder located between the stroke range and the open end of the working cylinder.

[0042] The smaller distance at the end results in a smaller cross-sectional area of ​​the compensation chamber perpendicular to the stroke axis at the end. This causes the compensating piston to be moved further towards the closed end of the compensating cylinder by the expansion of the compensating medium for a given temperature increase, thus increasing the working space and providing greater compensation for the temperature dependence of the gas spring's spring force.

[0043] Since the distance in the stroke area of ​​the working piston is not reduced, the compensation chamber can still hold a sufficient amount of compensating medium for effective temperature compensation.

[0044] The distance is, for example, 10% to 50%, preferably 20% to 40%, and particularly preferably 30% smaller in the end region than in the stroke region. The distance in the end region is, for example, 1 mm to 8 mm, preferably 2 mm to 4 mm, and particularly preferably 2.5 mm. In the stroke region, the distance is, for example, 2 mm to 12 mm, preferably 3 mm to 6 mm, and particularly preferably 3 mm to 3.5 mm. With these distance values, a largely, and in particular completely, compensation of the temperature dependence of the spring force of the gas spring can be achieved over a typical operating temperature range of the gas spring, for example, from -10 °C to +60 °C.

[0045] Preferably, the distance between the compensating cylinder and the working cylinder in the end region and / or in the stroke region is independent of any position along the stroke axis. In this embodiment, the distance is constant in the end region and / or in the stroke region along the stroke axis, making the gas spring particularly easy to manufacture.

[0046] The radial outer diameter of the working cylinder at its end, measured relative to the stroke axis, is preferably larger than the radial outer diameter of the working cylinder within its stroke range. This widening of the working cylinder at its end reduces the distance between the working cylinder and the compensating cylinder without altering the compensating cylinder or the shape of the working cylinder within the stroke range. Thus, the reduced distance is achieved with minimal modifications compared to a prior art gas spring. This makes the gas spring particularly easy and cost-effective to manufacture, especially using known components and methods.

[0047] The outer diameter at the end of the working cylinder is preferably 101% to 150%, more preferably 105% to 130%, particularly preferably 110% to 120%, and most preferably 112% to 113% of the outer diameter at the stroke of the working cylinder. The outer diameter at the end of the working cylinder is, for example, 15 mm to 25 mm, more preferably 16 mm to 22 mm, and particularly preferably 18 mm to 21 mm. The outer diameter at the stroke is, for example, 10 mm to 20 mm, more preferably 15 mm to 19 mm, and particularly preferably 17 mm to 18 mm. With these outer diameter values, a substantial compensation of the temperature dependence of the spring force of the gas spring can be achieved over a typical operating temperature range.

[0048] Preferably, the outer diameter of the working cylinder in the end region and / or in the stroke region is independent of its position along the stroke axis. In this embodiment, the distance is constant in the end region and / or in the stroke region along the stroke axis, making the gas spring particularly easy to manufacture.

[0049] The radial inner diameter of the compensating cylinder, measured to the stroke axis, is preferably 110% to 200%, more preferably 140% to 170%, particularly preferably 150% to 160%, and most preferably 155% to 157% of the stroke range outer diameter of the working cylinder. The inner diameter of the compensating cylinder is, for example, 20 mm to 30 mm, more preferably 23 mm to 27 mm, and particularly preferably 25 mm. With these values ​​for the inner diameter of the compensating cylinder, a substantial compensation of the temperature dependence of the spring force of the gas spring can be achieved over a typical operating temperature range of the gas spring.

[0050] 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.

[0051] The stroke section and the end section of the working cylinder are preferably integrally connected. The stroke section and the end section can be joined, for example, by a material bond, in particular by welding, brazing, and / or bonding. Alternatively, the stroke section and the end section can be joined, for example, by a positive and / or force-fit connection, in particular by screwing, snapping, and / or clamping.

[0052] The working cylinder can, for example, comprise or consist of a metal, in particular steel, and / or a plastic.

[0053] The wall thickness of the working cylinder radially to the stroke axis is preferably essentially the same in the stroke region and in the end region of the working cylinder, particularly except for a reduction in wall thickness caused by a widening of the working cylinder in the end region, for example by a reduction of up to 0.2 mm, and 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.

[0054] The wall thickness of the compensating cylinder radial to the stroke axis is preferably independent of its position along the stroke axis. In this design, the wall thickness of the compensating cylinder is constant along the stroke axis, making the gas spring particularly easy to manufacture.

[0055] The working cylinder and / or the compensating cylinder preferably comprises a non-homogeneously drawn tube, for example a tube with a weld seam along the stroke axis.

[0056] The process for manufacturing the gas spring involves forming or machining a compensating piston blank into the compensating piston. The compensating piston can be manufactured, for example, by deep drawing a compensating piston blank made of aluminum.

[0057] The method preferably comprises providing a working cylinder blank, preferably in the form of a non-homogeneously drawn tube, wherein the working cylinder blank is hollow cylindrical and has an outer diameter transverse to the longitudinal axis that is independent of its position along its longitudinal axis. The outer diameter is therefore 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 an azimuth with respect to its longitudinal axis, for example, by means of a weld seam along the longitudinal axis. Such a working cylinder blank is particularly easy and cost-effective to manufacture, for example, by drawing it from steel and welding it.

[0058] The method preferably comprises forming the working cylinder blank into the working cylinder of the gas spring, wherein the forming comprises widening the outer diameter of the working cylinder blank in at least one end region of the working cylinder blank.

[0059] The expanding process preferably comprises inserting a mandrel into the at least one end region and, more preferably, arranging a sleeve circumferentially around the longitudinal axis around the end region of the working cylinder blank before inserting the mandrel, so that the end region rests against the sleeve after expanding. This advantageously allows the diameter of a working cylinder blank, whose material properties depend on an azimuth with respect to its longitudinal axis, to be expanded to a diameter independent of the azimuth. Brief description of the drawings

[0060] Figure 1shows, by way of example, a schematic longitudinal section along the stroke axis of an embodiment of the gas spring according to the invention. Figure 2 shows, by way of example, a schematic longitudinal section along the stroke axis of another embodiment of the gas spring according to the invention. Fig. 1

[0061] Figure 1 shows a schematic longitudinal section along the stroke axis H of an embodiment of the gas spring 50 according to the invention.

[0062] The gas spring 50 shown comprises a working piston 2 slidably guided in a working cylinder 1 along a stroke axis H over a stroke range HB, a compensating cylinder 12 radially surrounding the working cylinder 1 to the stroke axis H, and a hollow cylindrical compensating piston 10 slidably guided in the compensating cylinder 12 along the stroke axis H relative to the working cylinder 1 and the compensating cylinder 12.

[0063] The working cylinder 1 has an open end 1b along the stroke axis H, wherein the compensating cylinder 12 forms a projection 15 over the working cylinder 1 with a closed end 15b along the stroke axis H at the open end 1b.

[0064] The compensating piston 10 separates a working chamber 1a arranged in the working cylinder 1, a compensating chamber 12a arranged between the working cylinder 1 and the compensating cylinder 12 and a return chamber 15a arranged in the projection 15 from each other.

[0065] The compensating piston 10 comprises, on an underside facing the return chamber 15a, a cylinder base 10b and a cylinder jacket 10c arranged sectionally between the working cylinder 1 and the compensating cylinder 12. The compensating piston 10 is open on an upper surface 10a facing the working chamber 1a.

[0066] The gas spring 50 includes a seal 8 arranged on the upper side 10a of the compensating piston 10, for example a sealing ring concentric to the stroke axis H. The seal 8 seals the compensating piston 10 against the working cylinder 1 and the compensating cylinder 12.

[0067] At a piston rod end 1c of the working cylinder 1 opposite the open end 1b along the stroke axis H, a piston rod 6 attached to the working piston 2 is preferably led out of the working cylinder 1 through a sealing device 20.

[0068] In the Figure 1 In the embodiment shown, the radial distance of the compensating cylinder 12 from the working cylinder 1, measured to the stroke axis H, is greater in the stroke range HB than in an end range EB of the working cylinder 1 located between the stroke range HB and the open end 1b of the working cylinder 1.

[0069] The reduced distance in the end region EB is achieved in this embodiment by having an outer diameter EAD of the working cylinder 1, measured radially to the stroke axis H, that is larger than an outer diameter HAD of the working cylinder 1, measured radially to the stroke axis H, in the stroke region HB. The outer diameter EAD of the end region is, for example, 18 mm to 21 mm and is preferably constant over the end region EB. The outer diameter HAD of the stroke region is, for example, 17 mm to 18 mm and is preferably constant over the stroke region HB.

[0070] For example, the inner diameter AID of the compensating cylinder 12 is 25 mm and is preferably constant along the stroke axis H. Fig. 2

[0071] Figure 2 shows a schematic longitudinal section along the stroke axis H of a further embodiment of the gas spring 50 according to the invention.

[0072] The in Figure 2The gas spring 50 shown differs from the one in Figure 1 The gas spring 50 shown is characterized in that the working cylinder 1, in a sealing area DB between the stroke area HB and the piston rod end 1c of the working cylinder 1, where the piston rod 6 exits the working cylinder 1, has a sealing area outer diameter DAD measured radially to the stroke axis H, which is larger than the stroke area outer diameter HAD of the working cylinder 1. The sealing area outer diameter DAD is, for example, 18 mm to 21 mm and is preferably constant over the sealing area DB. List of reference symbols 1 Working cylinder 15 Overhang 1a Inner workspace 15a Storage room 1b open ending 15b closed ending 1c Piston rod end 18 Guide element 2 working piston 20 Sealing device 6 piston rod 50 Gas spring 8 seal AID Balance cylinder inner diameter 10 Compensating piston DAD Sealing area outer diameter 10a Top DB Sealing area 10b Cylinder base EAD End-range outer diameter 10c Cylinder shell EB End area 10d Cylinder brim H Lifting axle 12 balance cylinder HAD Stroke range outer diameter 12a Compensation area HB Lifting range

Claims

1. Gas pressure spring (50) comprising: a. a working piston (2) movably guided in a working cylinder (1) along a stroke axis (H) over a stroke region (HB), b. a compensating cylinder (12) enclosing the working cylinder (1) radially to the stroke axis (H), and c. a compensating piston (10), hollow cylindrical in shape, which is movably guided in the compensating cylinder (12) along the stroke axis (H), d. the working cylinder (1) comprising an open end (1b) along the stroke axis (H), e. the compensating cylinder (12) forming, at the open end (1b), a projection (15) over the working cylinder (1) that has a closed end (15b) along the stroke axis (H), f. the compensating piston (10) i. separating from each other, in a gas-tight manner, a working chamber (1a) arranged in the working cylinder (1), a compensation chamber (12a) arranged between the working cylinder (1) and the compensation cylinder (12), and a resetting chamber (15a) arranged in the projection (15), and ii. being open at an upper side (10a) of the compensating piston (10) facing the working chamber (1a), characterized by g. a seal (8) arranged on the upper side (10a) of the compensating piston (10), which seals the compensating piston (10) from the working cylinder (1) and from the compensating cylinder (12).

2. Gas pressure spring (50) according to claim 1, characterized in that the compensating piston (10) is sealed exclusively by the seal (8) from the working cylinder (1) and from the compensating cylinder (12).

3. Gas pressure spring (50) according to claim 1 or claim 2, characterized in that the seal (8) comprises a sealing ring running around the stroke axis (H), preferably is a sealing ring running around the stroke axis (H).

4. Gas pressure spring (50) according to any of claims 1 to 3, characterized in that the seal (8) comprises a polyurethane and / or an acrylonitrile-butadiene rubber, preferably consists of a polyurethane or an acrylonitrile-butadiene rubber.

5. Gas pressure spring (50) according to any of claims 1 to 4, characterized in that the compensating piston (10) is in one piece.

6. Gas pressure spring (50) according to any of claims 1 to 5, characterized in that the compensating piston (10) comprises aluminum or a plastics material, preferably consists of aluminum or a plastics material.

7. Gas pressure spring (50) according to any of claims 1 to 6, characterized by a guide element (18) which movably guides the compensating piston (10) relative to the compensating cylinder (12) along the stroke axis (H), the guide element (18) preferably comprising a guide sleeve arranged in the projection (15) between the compensating cylinder (12) and the compensating piston (10).

8. Gas pressure spring (50) according to any of claims 1 to 7, characterized in that a. the compensating piston (10) comprises a cylinder jacket (10c) arranged in portions between the working cylinder (1) and the compensating cylinder, b. the compensating piston (10) comprising a cylinder rim (10d) adjacent to the upper side (10a) and projecting radially to the stroke axis (H) beyond the cylinder jacket (10c), c. the seal (8) being arranged on the cylinder rim (10d).

9. Gas pressure spring (50) according to any of claims 1 to 8, characterized in that a distance of the compensating cylinder (12) from the working cylinder (1), measured radially to the stroke axis (H), is greater in the stroke region (HB) than in an end region (EB) of the working cylinder (1) that lies between the stroke region (HB) and the open end (1b) of the working cylinder (1).

10. Gas pressure spring (50) according to claim 9, characterized in that an end region outer diameter (EAD) of the working cylinder (1), measured radially to the stroke axis (H), is larger than a stroke region outer diameter (HAD) of the working cylinder (1) in the stroke region (HB), measured radially to the stroke axis (H).

11. Gas pressure spring (50) according to any of claims 9 to 10, characterized in that the stroke region (HB) and the end region (EB) of the working cylinder (1) are integrally connected to one another.

12. Gas pressure spring (50) according to any of claims 1 to 11, characterized in that the working cylinder (1) in a sealing region (DB) between the stroke region (HB) and a piston rod end (1c) of the working cylinder (1) opposite the open end (1b) along the stroke axis (H), at which piston rod end a piston rod (6) attached to the working piston (2) emerges from the working cylinder (1), has a sealing region outer diameter (DAD), measured radially to the stroke axis (H), which is larger than the stroke region outer diameter (HAD) of the working cylinder (1).

13. Method for producing the gas pressure spring (50) according to any of claims 1 to 12, characterized by the step of: forming or machining a compensating piston blank into the compensating piston (10).

14. Method according to claim 13, characterized by the steps of: a. providing a working cylinder blank, the working cylinder blank being hollow cylindrical in shape and having an outer diameter transverse to the longitudinal axis that is independent of a position along the longitudinal axis of said blank, and b. forming the working cylinder blank into the working cylinder (1) of the gas pressure spring (50), c. the forming comprising expanding the outer diameter of the working cylinder blank in at least one end region of the working cylinder blank.

15. Method according to claim 14, characterized in that the expansion comprises inserting a mandrel into the at least one end region and preferably arranging a sleeve running around the longitudinal axis around the end region before inserting the mandrel, so that the end region rests against the sleeve after expansion.