Self-adjusting damper unit

Abstract

The present invention relates to a self-adjusting damper unit (10) comprising a cylinder (12) having a first working chamber (18) and a second working chamber (20), a piston (14), a piston rod (22), and a through hole (34, 36, 38, 40) between the first working chamber (18) and the second working chamber (20), the damper unit (10) also comprising a movable weight (26) for varying a passage cross section (42) of the through hole (34, 36, 38, 40), the movable weight (26) being movably mounted such that retardation of the piston (14) causes an increase in the passage cross section (42). The present invention also relates to a seat belt unit comprising a seat belt and the damper unit (10).

Description

[Technical Field]

[0001] The present invention relates to a self-adjusting damper unit comprising a cylinder filled with a fluid, a piston dividing the interior of the cylinder into a first working chamber and a second working chamber and displaceably disposed within the cylinder, a piston rod connected to the piston and extending from the cylinder at one end, and at least one through-hole configured to place the first working chamber in fluid communication with the second working chamber. [Background technology]

[0002] There are various applications in which it is desirable to independently adjust the damper units themselves. For example, uniformly cushioning different-sized masses with a single damper unit may be desirable in industrial applications. In another example, modern vehicles employ various safety systems to protect occupants during a collision. These include, for example, belt tensioners, airbags, or belt force limiters. Belt tensioners first ensure that a belt that may be too loosely fastened is pretensioned against the occupant. Airbags are then deployed in very rapid succession. By allowing the belt to yield, or unwind, a predetermined distance to protect the occupant's shoulder area and simultaneously maximize the effectiveness of the airbag, belt force limiters ensure that the occupant's head contacts the airbag after a certain time and / or distance, preventing the critical load on the shoulder area from being exceeded. Summary of the Invention

[0003] However, systems known from the prior art are not adapted, or are only adapted by including additional sensors, to adjust the force required in the belt force limiter in response to occupants of different weights in order to restrain the occupant in a way that ensures that the occupant is not injured or at least reduces the risk of injury.

[0004] It is therefore an object of the present invention to provide a self-adjusting damper unit which can be used, for example, as a belt force limiter and which is designed to adapt to the weight of the occupant.

[0005] This problem is solved by a self-adjusting damper unit comprising: a cylinder filled with a fluid; a piston displaceably arranged in the cylinder, dividing the interior of the cylinder into a first working chamber and a second working chamber; a piston rod connected to the piston and exiting the cylinder at at least one end thereof; and at least one through hole configured to place the first working chamber in fluid communication with the second working chamber, wherein the damper unit further comprises a movable weight configured to change the available passage cross-section of the at least one through hole allowing the passage of a fluid by its relative movement with respect to the at least one through hole, the movable weight being movably mounted with respect to the at least one through hole in such a way that a retardation of the moving piston or the moving piston rod causes an enlargement of the passage cross-section of the at least one through hole.

[0006] In this respect, it should be noted that the expression "changing (modifying) the available passage cross section" can include both partial and complete closing of the passage cross section. In other words, the movable weight may be arranged in a first position, e.g., a rest position, to at least partially close the through-hole in order to reduce (or prevent) the fluid flow from one working chamber to the other working chamber to a value corresponding to the available passage cross section of the through-hole, and in a second position, e.g., a release position, the movable weight is maximally displaced from the rest position in order to at least partially, in particular completely, release the through-hole in order to increase the fluid flow from one working chamber to the other working chamber.

[0007] To illustrate the principle on the example of a belt force limiter, the movable mass may be arranged on the piston rod in such a way that, during an initial acceleration on the piston rod, the movable mass is held in its rest position and the damper unit has a damping force corresponding to the passage cross-section of the at least one through-hole available for fluid flow, and as soon as the acceleration on the piston rod decreases, the movable mass is displaced by its inertia from its rest position towards the release position, so that the passage cross-section increases and the corresponding damping force of the damper unit decreases. Of course, the damper unit according to the invention may be suitably configured for a pressure load on the piston rod, i.e. for the piston rod to press the damper unit into the cylinder.

[0008] In this way, a damper unit can be provided that can keep the acceleration of the piston rod, i.e., in the case of the belt force limiter, the belt, constant regardless of the speed and / or force acting on the belt. The available damper distance can therefore be used to optimum effect. In the case of the belt force limiter, the damper unit according to the present invention allows a heavier person to experience higher shoulder forces via the belt than a lighter person, but the belt speed is reduced by the same amount for the same damper distance, regardless of the person's weight. The damper unit can therefore be made sensitive to the occupant.

[0009] The damper unit according to the invention may for example have a stroke of 150 mm and / or allow a movement speed of 15 m / s.

[0010] It should also be noted that the damper unit according to the invention can operate without any electrical power supply. It is therefore possible to provide a fully functional damper unit even in the event of a complete failure of the vehicle's electrical system. This means that no sensor devices need to be electrically operated, and no information is required from the vehicle sensor system to adjust the operation of the damper unit depending on the occupant.

[0011] It is also conceivable that the piston rod emerges from the cylinder at both longitudinal ends. In such an embodiment, the piston may not be located at the longitudinal ends of the piston rod, but may be located, for example, approximately in the middle of the length of the piston rod. Thus, for example, the cylinder of the damper unit can be completely filled with fluid. This reduces turbulence of the damping fluid (e.g., oil) during operation of the damper unit, so that the damper unit can be used regardless of position, since the cylinder essentially no longer contains gas.

[0012] Furthermore, a compensation reservoir, a diaphragm reservoir, or the like can be provided. If the reservoir is used in a pressurized working chamber, a valve can also be provided. This means that the damper unit can be operated in any position even with the piston rod protruding from only one end, since the volume compensation is located outside the working chamber. This may be particularly practical for twin-tube dampers, diaphragm dampers, etc.

[0013] In a further embodiment of the invention, a seal may be disposed around the periphery of the piston to seal the piston to the cylinder, thereby preventing fluid from flowing from one working chamber past the periphery of the piston into the other working chamber.

[0014] Advantageously, an elastic element, in particular a spring, can be connected to the movable mass, which is configured to urge the movable mass into its rest position. On the one hand, this can ensure that the movable mass is actually in its rest position when the piston rod starts to move, and on the other hand, the spring constant of the elastic element can be used to set the delay required to move the movable mass from its position towards a release position against the spring force of the elastic element. It should be noted that, in general, the rest position and / or the release position can be defined relative to the through-hole. Furthermore, the elastic element can return the movable mass to the rest position after the damper unit has been triggered, thereby enabling the damper unit to be used multiple times.

[0015] The elastic element connected to the movable mass can be configured to exert a predetermined force on the movable mass also when the movable mass is in the rest position, which in particular allows a predetermined pretension to be exerted on the movable mass in its rest position, so that the force required to allow the movable mass to leave its rest position can be defined very precisely.

[0016] In particular, a stop can be provided against which the elastic element connected to the movable mass presses the movable mass, by means of which the rest position of the movable mass can be defined and approached by the movable mass in a repeatable manner by the elastic element. The stop can, for example, be configured as a protrusion projecting radially outward from the piston rod, which can in particular be formed integrally with the piston rod, or as a spring washer engaging in a groove in the piston rod.

[0017] Furthermore, when the movable weight is in the rest position, a certain portion of the at least one through-opening may remain open for fluid to pass through. This can be achieved, in particular, by the movable weight not completely closing the through-opening in its rest position. However, there may be a fluid communication between the two working chambers that is not obscured by the movable weight. In this way, an initial fluid flow can be defined at the start of the movement of the piston rod or piston in the cylinder of the damper unit. However, the movable weight can also completely close the through-opening. For this purpose, an additional overflow cross-section should be added at another point in the piston system. In particular, this should correspond to the passage cross-section that would otherwise correspond to the movable weight in its maximum closed position. In this way, the corresponding cross-section can be enlarged for a given installation space.

[0018] The open cross section of the through opening relative to the rest position of the movable mass is e.g. 1 mm 2 to 4mm 2 , especially about 2.5 mm 2 The fully opened cross section of the through opening can be, for example, 4 mm 2 from 10mm 2 , especially about 6 mm 2 The ratio of the fully opened cross section of the through opening to the cross section of the through opening associated with the rest position of the movable weight may be, for example, 1 to 10, in particular 1 to 4. Of course, this depends greatly on the scaling and the intended use of the damper unit, and cross sections and ratios deviating from those mentioned above are also possible within the scope of the present invention.

[0019] It is also conceivable that when the movable mass is in the rest position, no through-opening remains open (even partially) between the two working chambers. In this case, a compressible damping fluid, for example a gas such as air, can be used in the cylinder of the damper unit according to the invention to provide initial damping. Also, a first part of the working chambers can contain a compressible damping fluid and a second part of the working chambers can contain an incompressible damping fluid, so that two functions can be combined.

[0020] Advantageously, the piston rod may have a longitudinal bore extending over at least a portion of its length. This longitudinal bore of the piston rod may thus form part of the through-hole. In particular, the longitudinal bore may be arranged coaxially with the central longitudinal axis of the piston rod. Furthermore, the longitudinal bore may extend, in particular, in the area where the piston is arranged on the piston rod. In the area of ​​the longitudinal bore at the end opposite the piston, at least one transverse bore may extend radially outwardly relative to and from the longitudinal bore in order to fluidly connect the two working chambers via the longitudinal bore and the at least one transverse bore. In such an embodiment, this transverse bore may be considered the through-hole that is at least partially covered by the movable weight in the rest position.

[0021] It is also possible to provide further through-holes which are partially or completely closed by the movable weight in its rest position and which are opened by displacement of the movable weight from its rest position to allow the passage of fluid. These further through-holes can be realized both by the above-mentioned transverse holes and by additional connections of the two working chambers, such as the through-hole of the piston which can be at least partially covered by the movable weight in its rest position at the same time as the at least one transverse hole.

[0022] In particular, a further stop can be provided, against which the movable mass comes into contact (opposite, located) when maximally displaced from its rest position, in this position of the largest through-opening, referred to as the "release position" above, a larger passage cross section is free for the flow of fluid between the two working chambers than when the movable mass is in its rest position. This stop can, for example, be configured as a tube projecting from the piston towards the movable mass, inside which part of the piston rod passes.

[0023] The damper unit may further include an impulse absorber that contacts the movable mass in its initial rest position. An impulse absorber in the sense of the present invention is a mass that can absorb an initial impulse applied to the movable mass during the initial acceleration of the piston rod to prevent the movable mass from releasing from the stop associated with the rest position of the movable mass. The impulse absorber may, for example, be ring-shaped. In this case, the impulse absorber may be mounted on a tube that protrudes from the piston with its inner diameter toward the movable mass, forming the stop for the release position. A predetermined gap may be left between the outer diameter of the impulse damper and the inner surface of the cylinder wall of the damper unit, allowing the fluid located between the piston and the impulse damper to flow past the impulse damper. For this purpose, the impulse absorber may also be provided with a through hole and / or an inner and / or outer diameter that is non-circular in the circumferential direction, e.g., a notch.

[0024] For this purpose, the impulse absorber can be connected to an elastic element that pushes it toward the movable mass. This means that an impulse applied to the movable mass is transmitted to the impulse absorber according to the principle of conservation of momentum, thereby ensuring that the movable mass is only displaced from the rest position toward the release position following a corresponding large deceleration of the piston rod, and is not already transmitted by the initial impulse on the piston rod or the movable mass. The impulse absorber can be supported relative to the piston by a spring, which is arranged radially outside the tube, which serves as a stop for the movable mass in the release position. Thus, in an exemplary embodiment, the radial sequence can start from the piston rod, then the elastic element connected to the movable mass, then the stop for the release position of the movable mass, the elastic element connected to the impulse absorber, and finally the wall of the cylinder of the damper unit. In particular, the spring constant of the elastic element of the impulse absorber can be much smaller than the spring constant of the elastic element connected to the movable mass. The preload force with which the elastic element pushes or presses the impulse absorber towards the movable mass can be configured, for example, to just exceed the force of gravity on the impulse absorber. This ensures that the impulse absorber contacts (opposes, lies) against the movable mass, regardless of the orientation of the damper unit in the mounted state. It further ensures that the impulse absorber can be returned to this position after displacement from the position where it contacts (opposes) against the movable mass.

[0025] At the same time, the surface of the movable mass configured to contact the movable mass and / or the surface of the impulse absorber configured to contact the movable mass can be provided with a texture that allows a surface adhesion to be defined between the movable mass and the impulse absorber. This texture of at least one of the two contact surfaces should be particularly suitable for reducing surface contact and therefore adhesion of the two surfaces to each other, because when an impulse is transmitted from the movable mass to the impulse absorber, the impulse absorber must be able to easily separate itself from the movable mass. For example, at least one of the two contact surfaces can be provided with a texture in the form of a surface spline profile.

[0026] It may also be desirable for the impulse absorber not to separate from the movable mass immediately upon receiving the initial impulse, for example, a predetermined setting of the surface adhesion between the impulse absorber and the movable mass may ensure that the movable mass is "carried along" by the impulse absorber over at least an initial extent, thereby allowing the movable mass to be displaced from its rest position immediately upon initiation of the initial impulse.

[0027] In this regard, it is noted that the features and advantages described with respect to the impulse absorber / movable mass pairing also apply to surface contact between the movable mass and the stop.

[0028] The movable mass may be non-rotatably mounted on the piston rod and / or may have a groove on its inner surface configured to establish fluid communication between the through-hole in which the movable mass is arranged and the working chamber, regardless of the rotational direction of the movable mass relative to the piston rod. Such a configuration of the damper unit makes it possible to avoid unintentional covering of the at least one through-opening, and thus to clearly define the movement or acceleration of the movable mass to and from the rest position.

[0029] The movable mass may have a protrusion that engages in a recess, in particular a groove, arranged on the piston rod so that the movable mass can be mounted non-rotatably on the piston rod.

[0030] In another aspect, the invention relates to a seat belt unit, in particular for a vehicle, comprising a seat belt and a self-adjusting damper unit according to the invention, wherein the seat belt is connected directly or indirectly to one of the piston rod and the cylinder, and the other of the piston rod and the cylinder is connected to a higher level assembly, in particular the vehicle body. Referring to the introduction, the self-adjusting damper unit according to the invention can be used as a belt force limiter for a vehicle seat belt, and the damper unit according to the invention allows occupant-sensitive damping, i.e. damping that automatically adjusts to the weight of the occupant.

[0031] The expression "directly or indirectly connected" should be understood to mean, for example, that the piston rod does not need to be in direct contact with the safety belt, as long as there is a force-transmitting connection between the two elements. Therefore, the connection between the seat belt according to the invention and the damper unit can be realized at at least one of the seat belt fastening points, for example for a three-point belt. More specifically, in a first example, the damper unit can be used in the belt's attachment (underside in the vehicle) and / or in the area of ​​the belt buckle and / or in the section associated with the belt retractor. In the section associated with the belt retractor, the damper unit according to the invention can be arranged, for example, between the vehicle body and a housing that can include further possible components of the seat belt unit, such as a belt tensioner, a non-return device, etc. The housing can be displaceable in a guide, such as a slide block guide. [Brief explanation of the drawings]

[0032] The invention will now be explained in more detail with reference to the drawings, which show: [Figure 1] FIG. 1 is a side cross-sectional view of an embodiment of a damper unit according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] 1, a damper unit according to the present invention is generally designated by the reference numeral 10. The damper unit 10 comprises a cylinder 12 in which a piston 14 is disposed. The piston 14 is provided on its outer periphery with a sealing device 16 that seals against the inner surface of the wall of the cylinder 12, and the internal space of the cylinder 12 is divided by the piston 14 into a first working chamber 18 and a second working chamber 20. The internal space of the cylinder 12, including the two working chambers 18 and 20, is filled with a fluid, for example oil.

[0034] Before further describing the embodiment of the damper unit 10 according to the invention shown in FIG. 1, it should be noted that the damper unit 10 according to FIG. 1 is configured to be subjected to a pressure load, i.e. such that the piston rod 22 connected to the piston 14 is forced into the cylinder 12 (displacing the piston 14 towards the right in FIG. 1).

[0035] At the end of the cylinder 12 where the piston rod 22 emerges from the cylinder 12 , the first working chamber 18 is sealed fluid-tight to the outside of the damper unit 10 by a further sealing device 24 .

[0036] The movable weight 26 is disposed on the piston rod 22 so as to be displaceable in the longitudinal direction of the piston rod 22. In the illustrated exemplary embodiment, the movable weight 26 is also disposed rotatably relative to the piston rod 22. The movable weight 26 is pressed against a stop 30 by a spring 28, which is supported at one longitudinal end by the movable weight 26 and at the other longitudinal end by the piston 14. The stop 30 defines and limits the rest position of the movable weight 26 when the movable weight 26 is in contact with the stop 30. The stop 30 is configured here as a spring washer that engages in a circumferential groove in the piston rod 22. The spring 28 directly surrounds the piston rod 22 without contacting (opposing, being located) against the piston rod 22.

[0037] The tube 32 is connected to the piston 14 and extends from the piston 14 toward the movable weight 26, such that when the movable weight 26 is displaced from the release position into contact with the tube 32, the longitudinal end of the tube 32 opposite the piston 14 defines and limits the release position of the movable weight 26. The spring 28 is disposed within the tube 32 when viewed radially of the damper unit 10.

[0038] Coaxially with the center line X of the piston rod 22, a longitudinal bore 34 is arranged in the piston rod 22, which, on the one hand, opens into the second working chamber 20 at the end of the piston rod 22 where the piston 14 is arranged, and, on the other hand, ends as a blind hole in the area of ​​the piston rod 22 radially superimposed in its rest position by the movable weight 26. The through holes 36 extend radially outward from the longitudinal bore 34 relative to the piston rod 22, such that they are (in the present embodiment partly) covered by the movable weight 26 in its rest position.

[0039] The movable weight 26 has a circumferential groove 38 therein, from which again extends radially a hole 40. The holes 40, groove 38, through-hole 36, and longitudinal bore 34 thus place the first working chamber 18 and the second working chamber 20 in fluid communication with one another. A passage cross-section 42 associated with the rest position of the movable weight 26 is defined only by the partial overlap of the through-hole 36 by the movable weight 26. Due to the circumferential groove 38, the function of overlap is decoupled from the rotational direction of the movable weight 26 relative to the piston rod 22.

[0040] 1 , the movable weight 26 is pressed against the stop 30 by its inertia and the preload of the spring 28, and the fluid flows from the second working chamber 20 to the first working chamber 18, the flow rate being limited by the passage cross section 42. If the displacement of the piston rod 22 and therefore the movable weight 26 is delayed, the inertia of the movable weight 26 will cause it to move from its rest position towards its release position, i.e., out of contact with the stop 30, which will increase the passage cross section 42. This is because the displacement of the movable weight 26 will cause the hole 40 or groove 38 in the movable weight 26 to overlap more with the through-hole 36 that is located closer to the piston 14 than the hole 40 or groove 38 in the movable weight 26, relative to the rest position of the movable weight 26. In its released position, where the movable weight 26 contacts (opposes, lies against) the tube 32, the holes 40 or grooves 38 are brought into maximum overlap with the through holes 36.

[0041] The increase in passage cross section 42 causes an increase in the flow rate of fluid from second working chamber 20 to first working chamber 18, thereby reducing the overall damping force of damper unit 10. As retardation in piston rod 22 decreases, the action of spring 28 causes movable mass 26 to move back towards its rest position, again reducing passage cross section 42 and increasing the damping force of damper unit 10.

[0042] To prevent the first impulse introduced into the piston rod 22 from displacing the movable weight 26 away from the stop 30 (e.g., due to the elasticity of the materials used for the movable weight 26 and / or the stop 30 (e.g., metal)), the embodiment shown here includes an impulse absorber 44 that is configured to contact the movable weight 26 when the movable weight 26 is in its rest position and to absorb the impulse that is first introduced into the movable weight 26, causing this impulse to move the movable weight 26 away from the piston 14, thereby allowing the movable weight 26 to remain in its rest position (at this point). To this end, to ensure that the impulse absorber 44 contacts (opposes, lies against) the movable weight 26, the impulse absorber 44 is preloaded toward the movable weight 26 by a spring 46, which is supported on the piston 14 at its opposite end from the impulse absorber 44.

[0043] Here, the impulse absorber 44 is ring-shaped, its inner diameter is mounted on the outer surface of the tube 32, and can move translationally and rotationally. A spring 46 connected to the impulse absorber 44 is disposed radially outside the tube 32.

[0044] To allow the piston 14 to be connected to the piston rod 22, a limiting element 48 is provided on the piston rod 22, which limiting element is again configured as a spring washer that engages in a groove in the piston rod 22, the limiting element 48 being configured to limit the displacement of the piston 14 towards the movable weight 26. Opposite the limiting element 48, the piston 14 is fixed in position relative to the limiting element 48 by a fixing element 50, such as a nut.

[0045] It should be added here that the movable mass 26 is essentially bell-shaped, so that it has a larger diameter in the area where it abuts against the impulse absorber 44 than in the area where it abuts against the stop 30. This prevents the fluid flow to and from the first working chamber 18 from being restricted by the passage cross section 42 as well as by an excessively narrow gap between the bore 40 and the inner surface of the wall of the cylinder 12, which in some cases could be more restricted than by the passage cross section 42 and negatively influence or even prevent the operation of the damper unit 10 according to the invention.

Claims

1. A self-adjusting damper unit (10), comprising: a cylinder (12) filled with a fluid; a piston (14) that divides the interior of the cylinder (12) into a first working chamber (18) and a second working chamber (20) and is displaceably disposed within the cylinder (12); a piston rod (22) connected to the piston (14) and extending from the cylinder (12) at at least one end thereof; at least one through-hole (34, 36, 38, 40) configured to place the first working chamber (18) in fluid communication with the second working chamber (20); the damper unit (10) further comprises a movable weight (26) configured to change a passage cross-section (42) of the at least one through-hole (34, 36, 38, 40) available for the passage of a fluid by movement relative to the at least one through-hole (34, 36, 38, 40); the movable weight (26) is movably mounted relative to the at least one through hole (34, 36, 38, 40) such that deceleration of the moving piston (14) or the moving piston rod (22) causes an expansion of the passage cross section (42) of the at least one through hole (34, 36, 38, 40); an elastic element (28), in particular a spring (28), is connected to said movable mass (26), said element being configured to urge said movable mass (26) into its rest position; A self-adjusting damper unit is provided with a stop (30) against which the elastic element (28) connected to the movable weight (26) pushes the movable weight (26).

2. 2. The self-adjusting damper unit (10) of claim 1, wherein a seal (16) that seals the piston (14) against the cylinder (12) is disposed on the outer periphery of the piston (14).

3. 3. The self-adjusting damper unit (10) of claim 1 or 2, wherein the elastic element (28) connected to the movable weight (26) is configured to apply a predetermined force to the movable weight (26) even when the movable weight (26) is in the rest position.

4. 4. The self-adjusting damper unit (10) of claim 1, wherein when the movable weight (26) is in a rest position, a predetermined portion of the at least one through opening (36) remains open to allow fluid to pass through.

5. 5. The self-adjusting damper unit (10) of claim 1, wherein the piston rod (22) has a longitudinal bore (34) extending over at least a portion of the length of the piston rod (22).

6. 6. A self-adjusting damper unit (10) as claimed in any one of claims 1 to 5, characterized in that a further through hole (36) is provided which is partially or completely closed by the movable weight (26) in its rest position and which is opened for the passage of fluid upon displacement of the movable weight (26) from the rest position.

7. 7. The self-adjusting damper unit (10) of claim 1, wherein a further stop (32) is provided, against which the movable weight (26) comes into contact when the movable weight (26) is maximally displaced from its rest position.

8. 8. The self-adjusting damper unit (10) of claim 1, further comprising an impulse absorber (44) in contact with the movable weight (26) in an initial rest position.

9. 9. The self-adjusting damper unit (10) of claim 8, wherein the impulse absorber (44) is connected to a resilient element (46) that urges the impulse absorber (44) toward the movable weight (26).

10. 10. The self-adjusting damper unit (10) of claim 8 or 9, characterized in that a surface of the movable weight (26) configured to contact an impulse absorber (44) and / or a surface of the impulse absorber (44) configured to contact the movable weight (26) is provided with a texture, whereby a surface adhesion between the movable weight (26) and the impulse absorber (44) can be defined.

11. the movable weight (26) is non-rotatably attached to the piston rod (22), and / or 11. The self-adjusting damper unit (10) of claim 1, wherein the movable weight (26) has a groove (38) on its inner surface, the groove being configured to establish fluid communication between the through hole (36) and the working chamber (18) in which the movable weight (26) is disposed, regardless of the rotational direction of the movable weight (26) relative to the piston rod (22).

12. 12. The self-adjusting damper unit (10) according to claim 11, characterized in that the movable weight (26) has a protrusion that engages in a recess, in particular a groove, arranged on the piston rod (22) when the movable weight (26) is fixed so as not to rotate relative to the piston rod (22).

13. A seat belt unit, in particular for a vehicle, comprising a self-adjusting damper unit (10) according to any one of claims 1 to 12 and a seat belt, The seat belt unit is connected directly or indirectly to one of the piston rod (22) and the cylinder (12), and the other of the piston rod (22) and the cylinder (12) is connected to a higher level assembly, in particular a vehicle body.

Images