Pre-tightening device for safety belt and vehicle seat

Abstract

The invention relates to a pre-tightening device for a safety belt, the pre-tightening device comprises a pipe body, a pre-tightening assembly and a force transmission piece connected with the pre-tightening assembly, a gas chamber is formed between the pre-tightening assembly and the pipe body, the gas chamber can be filled with gas to promote the pre-tightening assembly to move in the pipe body in a first direction, and the force transmission piece is connected with the pre-tightening assembly. The first direction points to the second end portion of the pipe body from the first end portion of the pipe body, the pre-tightening assembly comprises a gas generator and a locking device, and the locking device is arranged between a gas outlet of the pre-tightening assembly and the first end portion of the pipe body. Gas from the gas generator can leave the pre-tightening assembly from the gas outlet and enter the pipe body, the pre-tightening device comprises a gas channel penetrating through the locking device, and the gas channel is communicated with the gas outlet and a first sub-cavity of the gas cavity. The first sub-chamber is located between the locker and the first end portion of the tube body. The invention also relates to a vehicle seat.

Description

Technical Field

[0001] This application generally relates to the field of vehicle safety. More specifically, this application relates to a pretensioner for a seat belt and a vehicle seat. Background Technology

[0002] Vehicle seat belts are a crucial component of a vehicle's occupant restraint system, providing protection for occupants in traffic accidents to prevent injury or reduce the severity of injury. Traditional seat belts, however, may not effectively conform to the occupant's body due to a gap that exists between the seat belt and the occupant before a collision. At the time of impact, this gap delays the seat belt's protective action, thus affecting its effectiveness.

[0003] Currently, several seatbelt pretensioners are known in the field of vehicle safety technology. Seatbelt pretensioners can be installed, for example, in the B-pillar of a vehicle or in the seat. Their function is to retract the webbing by a certain length using a ignited gas generator in the event of a collision, eliminating the gap between the occupant and the webbing. This prevents the occupant from being thrown forward due to inertia, reducing the injury sustained during a collision.

[0004] like Figure 1 As shown, in a known seatbelt pretensioner 300, gas from a gas generator 330 can be guided to a gas chamber 340 via an intake manifold 320 located at one end of the seatbelt pretensioner tube 310, thereby pushing a piston 350 in the tube and retracting the webbing. However, due to the arrangement of the intake manifold and the gas generator, such a seatbelt pretensioner occupies a large structural space. In particular, when the seatbelt pretensioner needs to be installed in a vehicle seat (i.e., the seatbelt pretensioner is configured as a "lumbar pretensioner"), the installation space available in the vehicle seat may be limited. Therefore, known seatbelt pretensioners may be difficult to meet the installation requirements in confined spaces, especially in vehicle seats. Summary of the Invention

[0005] The objective of this application is to provide a pretensioner for seat belts and a vehicle seat that overcomes at least one deficiency in the prior art. The pretensioner for seat belts should, in particular, have a more compact structure to meet the installation requirements of the pretensioner in confined spaces.

[0006] The task is accomplished by a pretensioning device for a seatbelt according to the present application and a vehicle seat according to the present application.

[0007] A first aspect of the present application relates to a pretensioning device for a safety belt, the pretensioning device comprising a tube, a pretensioning assembly and a force transmission connected to the pretensioning assembly, between the pretensioning assembly and the tube a gas chamber being formed, the gas chamber being fillable with gas to urge the pretensioning assembly to move in the tube in a first direction, the first direction pointing from a first end of the tube to a second end of the tube, wherein the pretensioning assembly comprises a gas generator and a lock, the lock being arranged between a gas outlet of the pretensioning assembly and the first end of the tube, from the gas outlet gas from the gas generator can exit the pretensioning assembly and enter the tube, the pretensioning device comprising a gas passage through the lock, the gas passage communicating the gas outlet and a first sub-chamber of the gas chamber, the first sub-chamber being located between the lock and the first end of the tube.

[0008] In the pretensioning device for a safety belt according to the present application, the pretensioning assembly can be located in the tube, between the pretensioning assembly and the tube a gas chamber being formed which is fillable with gas. The tube can be understood here as a so-called "cylinder", and the gas chamber can be understood here as a so-called "piston chamber", the volume of which can expand due to the filling of gas and thus urge the pretensioning assembly together with the force transmission connected to the pretensioning assembly to move. Seen in the axial direction of the tube, the gas chamber can be formed between the first end of the tube and the pretensioning assembly, so that upon filling of the gas chamber with gas, the pretensioning assembly can move as a whole in the tube in the first direction from the first end of the tube towards the second end of the tube.

[0009] In the present application, the pretensioning assembly comprises a gas generator, the gas generator being configured for generating gas to fill the gas chamber. To this end, the pretensioning assembly comprises a gas outlet, from which gas from the gas generator can exit the pretensioning assembly and enter the tube or, respectively, the gas chamber between the pretensioning assembly and the tube. In the present application, the gas generator is configured as an integral part of the pretensioning assembly and is movable in the tube. Since the gas generator is arranged within the tube and an intake manifold projecting from the tube is dispensed with, the overall dimensions, in particular the radial dimensions, of the pretensioning device according to the present application are essentially dependent only on the tube itself. Thus, the pretensioning device according to the present application has a compact design, which can be installed in a narrow construction space, in particular a tubular construction space. The pretensioning device of the present application is particularly suitable, for example, for installation in a seat tube column of a vehicle seat.

[0010] In the event of a vehicle collision, in particular after pretensioning of the pretensioning assembly in a first direction, the pretensioning assembly can be pulled by the force transmission in a second, opposite direction due to the forward movement of the occupant by inertia. The pretensioning assembly therefore comprises a lock arranged between the gas outlet of the pretensioning assembly and the first end of the tube. The lock is configured to limit the extent to which the pretensioning assembly is pulled in the second direction by the force transmission, in order to guarantee the restraining effect of the safety belt. In addition, the lock can also cushion the forward movement of the occupant to some extent and relieve the force of the safety belt on the occupant in the process.

[0011] The section of the gas chamber between the lock and the first end of the tube can be referred to as a first sub-chamber of the gas chamber, viewed in the axial direction of the tube. The volume change of the gas chamber during the filling of the gas chamber can essentially be caused by the volume expansion of the first sub-chamber. The pretensioning device here comprises a gas channel which runs through the lock and which connects the gas outlet and the first sub-chamber of the gas chamber. Gas from the gas generator can thus exit the pretensioning assembly via the gas outlet of the pretensioning assembly and enter the first sub-chamber of the gas chamber via the gas channel through the lock. Within the scope of the present application, the gas channel which runs through the lock and the gas which "passes through" the lock can be understood as meaning that the gas can flow through the gas channel from one side of the lock to the other side of the lock in the axial direction of the tube. By virtue of the above-described arrangement according to the application, on the one hand the locking function of the pretensioning device is provided by the lock, and on the other hand the gas from the gas generator can reliably fill the first sub-chamber and thus reliably implement the pretensioning process.

[0012] According to an embodiment of the application, the gas chamber comprises the first sub-chamber and a second sub-chamber, which are connected to one another via the gas channel, and the gas outlet of the pretensioning assembly opens into the second sub-chamber.

[0013] According to an embodiment of the application, the gas channel is formed between the lock and the inner wall of the tube and / or by the lock itself.

[0014] According to an embodiment of the application, the lock is arranged between the first end of the tube and the gas generator.

[0015] According to an embodiment of the application, during the filling of the gas chamber, the pretensioning assembly is subjected to a greater force from the gas in the first direction than in the second direction, the second direction being opposite to the first direction.

[0016] According to an embodiment of the application, during the filling of the gas chamber, the pretensioning assembly has a greater pressure area in the first direction than in the second direction.

[0017] According to an embodiment of the application, the compression area of the pre-tension assembly in the first direction corresponds to the difference between the inner cross-sectional area of the tube and the cross-sectional area of the force transmission member.

[0018] According to an embodiment of the application, the gas channel is configured rotationally symmetric about the central axis of the tube.

[0019] According to an embodiment of the application, the lock comprises a piston with a ramp and a locking element which can move along the ramp.

[0020] According to an embodiment of the application, the piston comprises a through-hole and / or the piston comprises a recess on the outer circumference, the gas channel being formed at least partially by the through-hole and / or the recess.

[0021] According to an embodiment of the application, the outer diameter of the piston is essentially the same as the inner diameter of the tube.

[0022] According to an embodiment of the application, the outer diameter of the piston is smaller than the inner diameter of the tube, the gas channel being formed at least partially by a radial gap between the piston and the tube.

[0023] According to an embodiment of the application, the piston comprises a piston head towards the first end of the tube and a piston body connected behind the piston head, the radial dimension of the piston head being larger than the radial dimension of the piston body in the region of the mutual connection of the piston head and the piston body.

[0024] According to an embodiment of the application, the compression area of the pre-tension assembly in the second direction comprises the difference between the cross-sectional area of the piston head and the cross-sectional area of the piston body in the region of the mutual connection of the piston head and the piston body.

[0025] According to an embodiment of the application, the radial dimension of the piston body increases in the first direction from the piston head, the outer circumferential surface of the piston body forming the ramp.

[0026] According to an embodiment of the application, the locking element is configured as a ball, in particular a metal ball, for example a steel ball, which lies between the outer circumferential surface of the piston body and the inner circumferential surface of the tube.

[0027] According to an embodiment of the application, the difference between the radius of the inner circumferential surface of the tube and the radius of the end of the piston body remote from the piston head is smaller than the diameter of the ball.

[0028] According to an embodiment of the application, the through-hole and / or the recess are configured in the piston head; and / or the through-hole and / or the recess are configured in the region of the end of the piston body remote from the piston head.

[0029] According to an embodiment of the application, both of the two end faces of the piston facing each other have substantially the same cross-sectional outer contour.

[0030] According to an embodiment of the application, the pre-tensioning assembly comprises a stopper fixedly connected to the force transmission member, the stopper being located between the gas generator and the lock.

[0031] According to an embodiment of the application, the pre-tensioning assembly comprises a sleeve configured to accommodate the stopper and the gas generator and to fix the stopper and the gas generator relative to each other.

[0032] According to an embodiment of the application, the gas outlet of the pre-tensioning assembly is formed in the sleeve.

[0033] According to an embodiment of the application, the pre-tensioning assembly comprises a stopper fixedly connected to the force transmission member, the lock being held between the stopper and the stopper.

[0034] According to an embodiment of the application, the lock, in particular the piston of the lock, comprises a through hole through which the force transmission member extends.

[0035] According to an embodiment of the application, the first sub-chamber is sealed relative to the outside by means of a first seal, and the second sub-chamber is sealed relative to the outside by means of a second seal.

[0036] According to an embodiment of the application, the force transmission member is configured as a webbing or a cable, for example a steel wire rope.

[0037] According to an embodiment of the application, the pre-tensioning device comprises a fixing element connected to the end of the force transmission member located outside the tube, the fixing element being configured for connection to a seat belt webbing.

[0038] According to an embodiment of the application, the pre-tensioning device comprises a crash block arranged on the first end portion of the tube on the outside, the crash block being configured to absorb the impact energy of the fixing element.

[0039] A second aspect of the application relates to a vehicle seat comprising a seat body and a pre-tensioning device for a seat belt according to the first aspect of the application.

[0040] According to an embodiment of the application, the pre-tensioning device is fixed in a seat tube of the vehicle seat by means of a mounting assembly.

[0041] According to an embodiment of the application, the seat tube is oriented in the transverse direction of the seat body.

[0042] According to one embodiment of this application, the mounting assembly includes at least one first fastener configured to pass through the tube body of the seat column and the pretensioning device.

[0043] According to one embodiment of this application, the at least one first fastener is disposed in the region of the first end of the tube body of the pre-tightening device.

[0044] According to one embodiment of this application, the mounting assembly includes two first fasteners arranged radially opposite each other.

[0045] According to one embodiment of this application, the mounting assembly includes two second fasteners configured to extend through the seat post transverse to the extension direction of the seat post, wherein a first end of the tube of the pretensioning device can abut against the two second fasteners, and a force transmission element of the pretensioning device can pass between the two second fasteners.

[0046] According to one embodiment of this application, the mounting assembly includes a third fastener configured to pass through the seat column and the pretensioning device, the third fastener being located in the axial direction between the second end of the pretensioning device tube and the pretensioning component of the pretensioning device.

[0047] According to one embodiment of this application, the installation assembly includes a limiting member configured to connect to the second end of the tube body of the pre-tightening device.

[0048] According to one embodiment of this application, the mounting assembly includes a cover plate configured to cover the second end of the seat column and the tube body and / or restrict the axial position of the tube body.

[0049] Other features of this application are derived from the accompanying drawings and the detailed description. All features and combinations thereof mentioned above in the specification, as well as features and combinations thereof mentioned below in the detailed description and / or shown separately in the drawings, can be used not only in the combinations given therefor, but also in other combinations, or in their individual states. Attached Figure Description

[0050] A better understanding of various aspects of this application will be achieved by reading the following detailed description in conjunction with the accompanying drawings, in which:

[0051] Figure 1 A seatbelt pretensioner known from the prior art is schematically shown;

[0052] Figure 2A pretensioning device for a seatbelt according to some embodiments of this application is schematically shown;

[0053] Figure 3 schematically shown Figure 2 A cross-sectional view of the pre-tightening device;

[0054] Figure 4 schematically shown Figure 2 Exploded view of the pre-tightening device;

[0055] Figure 5 schematically shown Figure 2 A pre-tightening device, wherein the tube body of the pre-tightening device is not shown;

[0056] Figure 6 Show Figure 2 A schematic diagram of the pre-tightening device in its initial state;

[0057] Figure 7 Show Figure 2 A schematic diagram of the pre-tightening device during the pre-tightening process;

[0058] Figure 8 schematically shown Figure 2 A perspective view of the piston of the preload device;

[0059] Figure 9 schematically shown Figure 8 Side view of the piston;

[0060] Figure 10 schematically shown Figure 2 The pressure-bearing area of ​​the pre-tightening device along the first direction and the pressure-bearing area along the second direction;

[0061] Figure 11 A vehicle seat according to some embodiments of this application is schematically shown;

[0062] Figure 12 A partial view of the vehicle seat is shown schematically;

[0063] Figure 13 The installation of a seat belt pretensioner in a seat column according to some embodiments of this application is schematically shown.

[0064] Figure 14 The installation of a seat belt pretensioner in a seat column is illustrated schematically according to some embodiments of this application. Detailed Implementation

[0065] The present application will now be described with reference to the accompanying drawings, which illustrate several embodiments of the present application. However, it should be understood that the present application can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present application more complete and to fully illustrate the scope of protection of the present application to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0066] It should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit this application. All terms used in this specification (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0067] Unless otherwise specified, the singular forms “a,” “the,” and “the” used in this specification include the plural forms. The terms “comprising,” “including,” and “containing” used in this specification indicate the presence of the claimed feature but do not exclude the presence of one or more other features. The term “and / or” used in this specification includes any and all combinations of one or more of the relevant listed items.

[0068] When a component is described in the specification as being "on", "attached" to, "connected" to, "joined" to, or "in contact" with another component, the component may be directly located on, attached to, connected to, joined to, or in contact with the other component, or there may be an intermediate component present.

[0069] In the specification, spatial relation terms such as "above," "below," "front," "back," "top," and "bottom" describe the relationship between one feature and another in the accompanying drawings. It should be understood that spatial relation terms include not only the orientation shown in the drawings but also the different orientations of the device during use or operation. For example, when the device in the drawings is inverted, a feature previously described as "below" other features can now be described as "above" other features. The device can also be oriented in other ways (rotated 90 degrees or in other orientations), in which case the relative spatial relationships will be explained accordingly.

[0070] Figures 2 to 4 A pretensioning device 100 for a seatbelt according to some embodiments of this application is shown. The pretensioning device 100 includes a tube 10 and a force transmitter 30. The force transmitter 30 may be constructed as webbing or cable, such as a steel wire rope. One end of the force transmitter 30 is located inside the tube 10, while the other end of the force transmitter 30, located outside the tube, may be connected to the seatbelt webbing 2, for example, via a fastening element 31. Figure 3, Figure 6 and Figure 7 Most clearly shown, the pre-tightening device 100 also includes a pre-tightening assembly 20 connected to the force transmitter 30, which is located within the tube 10 and is movable integrally within the tube 10. To achieve the connection between the pre-tightening assembly 20 and the force transmitter 30, the pre-tightening assembly 20 may include a limiting block 21, which may be riveted to the force transmitter 30, for example.

[0071] like Figure 6 and Figure 7 As shown, when the pretensioning assembly 20 moves along the first direction R1 within the tube 10, the pretensioning assembly 20 can drive the power transmission component 30, thereby causing the seat belt webbing 2 to retract a certain distance. The first direction R1 can start from the first end of the tube 10 ( Figure 6 (left side) points to the second end ( Figure 6 (Right side). This process can be referred to as the pretensioning process of the pretensioning device 100. Here, the first end of the tube 10 can be understood as the end from which the force transmission element 30 extends, and the extended force transmission element 30 can be connected to the seat belt webbing 2 via the fixing element 31. Therefore, the first end of the tube 10 can also be understood as the end closer to the seat belt webbing 2 in the installed state. The second end of the tube 10 is the end opposite to the first end of the tube 10 and therefore further away from the seat belt webbing 2. For example, when the pretensioning device 100 is used as a lumbar pretensioner, the pretensioning device 100 can be installed in a vehicle seat that can be positioned facing forward in the vehicle. In this case, the first end of the tube 10 can be closer to the corresponding door, while the second end of the tube 10 can be closer to the longitudinal centerline of the vehicle. Of course, the tube 10 is not limited to the straight type shown, and other construction types of the tube can be envisioned. For example, in an embodiment not shown, the tube 10 can be constructed to be at least partially curved. In addition, the tube 10 may have other diverse cross-sectional shapes as required, not limited to the circular cross-section shown.

[0072] exist Figure 6 In this configuration, the pre-tightening device 100 is in an inactive initial state, wherein the pre-tightening assembly 20 may be located near or abutting against the first end of the tube body 10. Figure 7 In the process of pre-tightening, the pre-tightening device 100 can be in the pre-tightening process, wherein the pre-tightening component 20 has been relative to... Figure 6 It moved a distance to the right toward the second end of the tube 10.

[0073] To achieve the above pre-tightening process, such as Figure 7As can be most clearly seen, a gas chamber 40 capable of being filled with gas is formed between the pre-tightening assembly 20 and the tube body 10. The gas chamber 40 can be sealed relative to the external space at one end by a first seal 41 and at the other end by a second seal 42. The first seal 41 can be disposed at the first end of the tube body 10 between the tube body 10 and the force transmission member 30, while the second seal 42 can be disposed between the pre-tightening assembly 20 and the tube body 10. More specifically, the tube body 10 can sequentially include a first tube body portion 11 and a second tube body portion 12 along a first direction R1. The first tube body portion 11 can be connected to the second tube body portion 12, for example by welding and / or bonding and / or riveting and / or threading, to form the tube body 10. Here, the first tube body portion 11 can be connected to the second tube body portion 12 at the first end of the tube body 10, and the force transmission member 30 can extend through a through-hole in the first tube body portion 11. Starting from the through hole through which the force transmission member 30 passes, the first tube portion 11 may have a first stepped portion 111 and a second stepped portion 112 that expands radially relative to the first stepped portion on its inner surface. A first sealing member 41 may be disposed in the region of the first stepped portion 111 between the inner surface of the first tube portion 11 and the force transmission member 30.

[0074] The initial position of the preload assembly 20 can be defined by the preload assembly 20 abutting against the first seal 41 and / or by the preload assembly 20 abutting against the end of the first tube portion 11 that extends into the second tube portion 12.

[0075] Furthermore, the pre-tensioning stroke (i.e., the distance the pre-tensioning assembly 20 can move within the tube body 10) can be defined by the length of the tube body 10 and / or the length of the force transmission member 30. The pre-tensioning assembly 20 can be blocked by the second end of the tube body 10, and / or the fixing element 31 of the force transmission member 30 can be blocked by the first end of the tube body 10, particularly the first tube body portion 11, thereby preventing further movement of the pre-tensioning assembly 20. A bumper 15 can be provided at the first end of the tube body 10, particularly on the first tube body portion 11, configured to absorb the impact energy of the fixing element 31 striking the tube body 10 at the end of the pre-tensioning process. The bumper 15 can extend from the first end of the tube body 10 along... Figure 6 and Figure 7 The second direction R2 extends a certain length. The anti-collision block 15 may include a through hole through which the force transmission member 30 extends.

[0076] Continue to refer to Figure 7To fill the gas chamber 40, the pretensioning assembly 20 includes a gas generator 22. The gas generator 22 can be located behind the limiting block 21 along a first direction R1 (viewed from left to right in the figure). Specifically, a line 27 of the gas generator 22 can extend from the second end of the tube 10 away from the tube 10. The line 27 can be connected, for example, to a vehicle control unit, which, in the event of a collision, can activate the gas generator 22 via the line 27, thereby triggering the pretensioning process of the pretensioning device 100.

[0077] The gas generator 22 can be housed together with the limiting block 21 in the sleeve 23 (see Figure 4 In the gas generator 22 and the limiting block 21 are fixed to each other by a sleeve 23. The sleeve 23 may be constructed as a metal part, particularly a thin-walled metal part, which may surround the limiting block 21 and the gas generator 22 in the circumferential direction, and deform radially inward, for example, at least at two end sides, to hold the limiting block 21 and the gas generator 22 together in the axial direction.

[0078] like Figure 4 As shown, the sleeve 23 may include a gas outlet 24 from which gas from the gas generator 22 can exit the sleeve and thus the preload assembly 20, and subsequently enter the gas chamber 40 to fill it. Viewed axially, the gas outlet 24 is located between the first seal 41 and the second seal 42. In some embodiments, the gas outlet 24 may be formed by at least one, particularly multiple, vent holes provided on the sidewall of the sleeve. For example, in some embodiments, the sleeve 23 may include two radially opposing vent holes. In other embodiments, the sleeve may also include more than two vent holes, which may be arranged on the sleeve as needed. For example, the vent holes may be circumferentially distributed, particularly uniformly distributed. Furthermore, vent holes spaced apart from each other in the axial direction may also be provided. Not limited to the circular vent holes shown, the vent holes may also have any suitable geometry, such as rectangular, elliptical, etc.

[0079] In a pretensioning device, besides pulling the seatbelt back a certain distance along the first direction R1 during the pretensioning process to eliminate the gap between the occupant and the webbing, it is also important for the safety of the seatbelt to prevent it from being pulled out again due to the occupant's inertia after the pretensioning process, and to limit the force exerted by the seatbelt on the occupant, thereby reducing or avoiding injury to the occupant due to the inextensibility of the seatbelt during restraint. Therefore, as... Figures 3 to 7 As shown, the pretensioning assembly 20 includes a locking member 25, which can be configured to limit the orientation of the force transmission member 30 of the pretensioning assembly 20 towards the pretensioning assembly 20. Figure 6 and Figure 7The degree of pulling in the second direction R2. By setting the locking device 25, it is possible to prevent the seat belt from being pulled out again by the occupant due to inertia, and it can also alleviate the force of the seat belt on the occupant during this process to a certain extent. This process can be called the locking process.

[0080] Generally, the locking device 25 achieves the locking process through interaction with the tube body 10. For this purpose, the locking device 25 may need to be in at least partial contact with the inner wall of the tube body 10. The wiring 27 of the gas generator 22 needs to extend from the side of the sleeve 23 away from the first end of the tube body 10. To facilitate the laying of the wiring 27 while ensuring the reliable operation of the locking device 25, such as... Figure 5 As can be most clearly seen, the locking device 25 can be disposed as part of the pretensioning assembly 20 between the gas outlet 24 of the pretensioning assembly 20 and the first end (or the first tube portion 11) of the tube body 10. That is, along Figure 6 and Figure 7 Viewed from left to right in the first direction R1, the locking device 25 is located before the sleeve 23 (and the limiting block 21 and gas generator 22 within the sleeve 23). Here, the locking device 25 and the sleeve 23 together form an integral part of the pre-tightening assembly 20 and are capable of moving together within the tube body 10. To hold the locking device 25 in place, viewed along the first direction R1, the pre-tightening assembly 20 may include a stop 26 located before the locking device 25. The stop 26 may be fixedly connected to the force transmitter 30, for example, by riveting. The locking device 25 may include a through hole through which the force transmitter 30 extends. Thus, the force transmitter 30 extends sequentially through the stop 26, the locking device 25, and the limiting block 21. Therefore, the locking device 25 can be held between the stop 26 and the limiting block 21. Advantageously, the stop 26, the lock 25, the limit block 21, or the sleeve 23 can be tightly abutted against each other in sequence, so that the lock 25 can be tightly clamped between the stop 26 and the limit block 21 without sliding along the force transmission member 30.

[0081] like Figure 7As can be clearly seen, since the locking device 25 is located between the gas outlet 24 of the pre-tightening assembly 20 and the first end of the tube 10, the gas chamber 40 can be divided into a first sub-chamber 43 and a second sub-chamber 44 by the locking device 25. Viewed axially, the first sub-chamber 43 can be understood as the section of the gas chamber 40 located between the locking device 25 and the first end of the tube 10 (or the first seal 41). The second sub-chamber 44 can be understood as the section of the gas chamber 40 located between the locking device 25 and the second seal 42. Viewed radially, the second sub-chamber 44 can be defined by the outer peripheral wall of the sleeve 23 and the inner peripheral wall of the tube 10, and the gas outlet 24 of the pre-tightening assembly 20 can enter the second sub-chamber 44. Since the locking device 25 and the sleeve 23 remain fixed relative to each other, the volume of the second sub-chamber 44 can remain substantially unchanged during the filling of the gas chamber 40, while the movement of the pre-tightening assembly 20 along the first direction R1 is mainly caused by the volume expansion of the first sub-chamber 43.

[0082] As mentioned above, the locking device 25 may need to contact at least partially with the inner wall of the tube 10 to achieve the locking process. Therefore, the presence of the locking device 25 may separate the first sub-chamber 43 and the second sub-chamber 44 from each other, thereby affecting the filling of the gas chamber 40, especially the first sub-chamber 43, to some extent. In order to connect the first sub-chamber 43 and the second sub-chamber 44 and ensure the reliable pre-tightening process of the pre-tightening device 100, according to the present invention, the pre-tightening device 100 includes a gas passage through the locking device 25. During the filling of the gas chamber 40, gas from the gas generator 22 can enter the second sub-chamber 44 through the gas outlet 24 and pass through the locking device 25 through the gas passage into the first sub-chamber of the gas chamber. Thus, on the one hand, gas from the gas generator 22 can reliably fill the gas chamber 40, especially the first sub-chamber 43, thereby reliably achieving the pre-tightening process; on the other hand, the locking process after the pre-tightening process can be reliably achieved by means of the locking device 25.

[0083] The following is combined with Figures 3 to 9 An embodiment of the locking device 25 and an exemplary implementation of the gas passage through the locking device 25 are described in more detail.

[0084] like Figure 4 As shown, the locking device 25 may include a piston 50 and a locking element 60. The piston 50 may have a ramp 51 (see Figure 1). Figure 8 and Figure 9The locking element 60 can move along the slope 51. The locking element 60 can be constructed as a sphere, such as a steel ball. The piston 50 can include a piston head 52 facing a first end of the tube 10 in the assembled state and a piston body 53 connected to the piston head 52. In the region where the piston head 52 and the piston body 53 are connected, the radial dimension of the piston head 52 can be larger than the radial dimension of the piston body 53. Starting from the piston head 52, the radial dimension of the piston body 53 can increase along a first direction R1, so that the outer peripheral surface of the piston body 53 can form the slope 51. Figure 3 , Figure 6 and Figure 7 As shown, the outer circumferential surface (slope 51) of the piston body and the inner circumferential surface of the tube body 10 can form a wedge-shaped groove, in which the locking member 60 can be located. When the pre-tightening device 100 is not activated and during the pre-tightening process, the locking member 60 can be supported on the washer 61 and located in the axial direction in the region of the piston body 53 near the piston head 52, where the piston body 53 has a small radial dimension. Therefore, the locking member 25 allows the pre-tightening assembly 20 to move along the first direction R1. When the pre-tightening assembly 20 is pulled, for example, by the force transmission member 30 along the second direction R2, the locking member 60 can move along the slope 51 (climb) and eventually lock between the piston body 53 and the tube body 10, thereby preventing further movement of the pre-tightening assembly 20 and achieving the locking function.

[0085] like Figure 9 As shown, starting from the piston head 52, the slope 51 can initially have a section with a small slope or a gentle gradient, followed by a section with a larger slope or a gentler gradient. Furthermore, the end 54 of the piston body 53 furthest from the piston head 52 can have a certain axial thickness d. This ensures that the ball can be reliably locked between the piston body 53 and the tube 10, without the ball moving further away from the piston 50 along the first direction R1 due to possible deformation of the piston 50. It is also advantageous that the piston 50 is constructed as a solid entity or at least has a certain radial thickness in the region of the slope 51 to avoid or reduce deformation of the piston 50, for example, during locking.

[0086] A gas passage connecting the second sub-chamber 44 and the first sub-chamber 43 can be formed between the locking device 25 and the inner wall of the tube body 10, particularly between the piston 50 of the locking device 25 and the inner wall of the tube body 10. Specifically, in some embodiments, the outer contour dimension of the piston 50, particularly the maximum outer contour dimension, can be smaller than the inner contour dimension of the tube body 10, thereby forming the gas passage through the gap between the piston 50 and the tube body 10. For example, when both the piston 50 and the tube body 10 have circular cross-sections, the outer diameter of the piston 50 can be smaller than the inner diameter of the tube body 10, so that the gas passage can have an annular cross-section. Here, the difference between the radius of the inner circumferential surface of the tube body 10 and the radius of the end 54 of the piston body 53 away from the piston head 52 can be smaller than the diameter of the sphere to ensure the locking action of the locking device 25.

[0087] Alternatively or additionally, the piston 50 itself may include a through-hole extending through the piston 50, which may form the gas passage. For example, a through-hole 55 (see [link to article]) may extend through the force transmission member 30. Figure 8 A plurality of through holes are provided through the piston 50. In some embodiments, the through holes through the piston 50 may penetrate the material body of the piston 50 along its entire axial length. It is understood that such through holes do not necessarily have to extend strictly axially, but may also extend obliquely or even curvedly, as long as gas can flow through the through holes from one side of the piston 50 to the other side. Alternatively or additionally, the through holes may also penetrate the material body of the piston 50 only along a portion of its axial length. For example, in Figure 8 and Figure 9 In the piston 50 shown, the through hole can be arranged relatively radially outward, so that the through hole only penetrates the piston head 52 and the end 54 of the piston body 53 away from the piston head 52, but does not penetrate the section of the piston body 53 with the slope 51. In this case, the through hole penetrating the piston head 52 and the through hole penetrating the end 54 of the piston body 53 do not necessarily have to be axially aligned with each other, but can also be arranged staggered from each other.

[0088] Alternative or additional land, such as Figure 8 As shown, the piston 50 may include at least one, preferably multiple, cavities 56 on its outer periphery. The piston 50 may have a reduced radius in the region of the cavities 56 relative to other regions on its outer periphery (those without cavities), thereby forming the gas passage between such cavities 56 and the tube body 10. The cavities 56 may be constructed, in particular, in the piston head 52 and in the end 54 of the piston body 53 away from the piston head 52. To ensure a locking effect, the sections of the piston 50 with the slope 51 may not have cavities 56. Figure 8In the piston 50, the piston head 52 may include six open portions 56, which may be evenly spaced apart from each other in the circumferential direction. The end 54 of the piston body 53 away from the piston head 52 may also include six open portions 56, which may also be evenly spaced apart from each other in the circumferential direction. In cross-section, the open portions 56 may have substantially the same shape. When viewed in the axial direction, the open portions 56 in the piston head 52 may be aligned with the open portions 56 in the piston body 53, so that the two opposing end faces of the piston 50 (i.e., one side of the piston head 52 and the side of the piston body 53 away from the piston head 52) may have substantially the same cross-sectional profile. However, it is also conceivable that the open portions 56 in the piston head 52 and the open portions 56 in the piston body 53, especially the end 54 of the piston body 53, may differ in number and / or shape. Alternatively, it is also possible for the various open portions 56 constructed on the piston head 52 to have different shapes from each other, and / or for the various open portions 56 constructed on the piston body 53 to have different shapes from each other.

[0089] Not limited to the illustrated embodiments, the void 56 can be achieved, for example, through a shape mismatch between the outer contour of the cross-section of the piston 50 and the inner cross-section of the tube 10. Exemplarily, the tube 10 can have a circular inner cross-section, while the piston 50 can have an elliptical cross-section. The area difference between the circular inner cross-section of the tube 10 and the elliptical cross-section of the piston 50, and the resulting gap between the tube 10 and the piston 50, also constitutes a void in the sense of this application.

[0090] It is understood that when the locking device 25, and particularly the piston 50 of the locking device 25, includes a through hole and / or a recess 56 extending through the piston 50, the outer diameter (here, the maximum outer diameter) of the locking device 25, and particularly the piston 50 of the locking device 25, can be substantially the same as the inner diameter of the tube body 10. In this case, the outer circumferential surface of the piston 50 can at least partially contact the inner wall of the tube body 10.

[0091] Preferably, the gas channel can be configured to be rotationally symmetrical about the central axis of the tube 10, which is advantageous in terms of stability, uniformity and balance when filling the gas chamber 40.

[0092] See Figure 6 and Figure 7 During the filling of gas chamber 40, the gas needs to flow from right to left through the locking device 25 in order to fill the first sub-chamber 43 and push the pre-tightening assembly 20 to the right along the first direction R1. When the gas flows from right to left through the locking device 25, it may exert a force along the second direction R2 on the locking device 25 and thus on the pre-tightening assembly 20 as a whole. Figure 6 and Figure 7The force acting to the left may, to some extent, affect the movement of the pre-tightening assembly 20 along the first direction R1. In this application, it can be specified that during the filling of the gas chamber 40, the force exerted on the pre-tightening assembly 20 by the gas along the first direction R1 is greater than the force exerted on the pre-tightening assembly by the gas along the second direction R2. Since the force on the pre-tightening assembly 20 is related to the pressure-bearing area of ​​the pre-tightening assembly 20 in the corresponding direction, during the filling of the gas chamber 40, the pressure-bearing area of ​​the pre-tightening assembly 20 along the first direction R1 can be greater than the pressure-bearing area of ​​the pre-tightening assembly 20 along the second direction R2.

[0093] Figure 10 An exemplary diagram illustrates the relationship between the pressure-bearing area S1 along the first direction R1 and the pressure-bearing area S2 along the second direction R2 of the pretensioning assembly 20. The pressure-bearing area S1 of the pretensioning assembly 20 along the first direction R1 can correspond to the difference between the inner cross-sectional area of ​​the tube body 10 and the cross-sectional area of ​​the force transmission member 30. When the inner cross-section of the tube body 10 and the cross-section of the force transmission member 30 are two concentric circles, in... Figure 10 The pressure area S1 of the pre-tightening assembly 20 along the first direction R1 is exemplarily represented as an annular region filled in black. Figure 10 In the image, the black annular area is partially obscured by a shaded area, which represents the pressure area S2 of the preload assembly 20 along the second direction R2. (Refer to...) Figure 8 The pressure-bearing area S2 of the pre-tightening assembly 20 along the second direction R2 can be included in the area where the piston head 52 and the piston body 53 are connected. The difference between the cross-sectional area of ​​the piston head 52 and the cross-sectional area of ​​the piston body 53 can also be understood as the area S2 of the end face 57 of the piston head 52 facing away from the first end of the tube body 10. Figure 10 The area S2 is represented by a shaded line. It can be seen that the pressure area S1 of the pre-tightening assembly 20 along the first direction R1 is greater than the pressure area S2 along the second direction R2. The difference in area between the annular region filled in black (pressure area S1 along the first direction R1) and the region filled in shaded line (pressure area S2 along the second direction R2) can be understood as the equivalent pressure area of ​​the pre-tightening assembly 20 during the filling of the gas chamber 40. Figure 10 The black area that is still visible and not covered by the shadow area indicates that the pretensioning component 20 is subjected to the resultant force along the first direction R1, so that the pretensioning component 20 will move along the first direction R1.

[0094] In some embodiments, such as Figure 8 As shown, the pressure-bearing area of ​​the preload assembly 20 along the second direction R2 may also include at least a portion of the area of ​​the end face 58 of the piston body 53 facing away from the first end of the tube body 10. For example, in the case where the piston 50 is close to the sleeve 23 (such as...Figures 3 to 6 As shown), the end face 58 of the piston body 53 may be partially blocked by the sleeve 23, so the pressure area of ​​the preload assembly 20 along the second direction R2 may also include the difference between the area of ​​the end face 58 of the piston body 53 and the cross-sectional area of ​​the sleeve toward the end of the piston 50.

[0095] By using the pretensioning device 100 for seat belts according to the present invention, a more compact structure of the pretensioning device 100 can be achieved while ensuring reliable pretensioning and locking functions, so as to meet the installation requirements of the pretensioning device 100 in vehicles, especially in the confined structural space of vehicle seats, such as in seat columns.

[0096] The following describes an exemplary installation method of the pretensioning device 100 according to the present invention in a vehicle seat 200.

[0097] Figure 11 An exemplary vehicle seat 200 is shown, which may include a seat body 210 and a pretensioner 100 for seat belts as described above. The seat body 210 may include a seat column 220 for housing the pretensioner 100, which may be connected to or constructed as part of a seat frame, for example. The pretensioner 100 may be secured in the seat column 220 by a mounting assembly. The seat column 220 and the pretensioner 100, particularly the tube 10 of the pretensioner 100, may have corresponding longitudinal extension shapes. For example, if the tube 10 includes a curved portion, the seat column 220 may also include a corresponding curved portion. Preferably, the seat column 220 and the pretensioner 100, particularly the tube 10 of the pretensioner 100, may be as follows: Figure 11 The structure shown is linear. The linear seat column 220 can be oriented substantially along the lateral direction of the seat body 210 and can extend through the left and right sides of the seat body 210. During installation, the preload device 100 can be positioned along... Figure 11 Insert it into the seat column 220 in the direction indicated by the middle arrow, and secure the two together with the help of the mounting components, which will be described in more detail below.

[0098] like Figure 6 and Figure 7 As shown, the pretensioning device 100 can be entirely located within the seat column 220. Only the seat belt webbing 2, connected to the force transmission member 30 within the seat column 220, extends from the first end side of the seat column 220 (left side in the figure). A seat belt guide 240 can be provided at the first end side of the seat column 220, which can cover the seat column 220 from the outside. The seat belt webbing 2 can pass through the seat belt guide 240 and, if necessary, deflect its extension direction via the seat belt guide 240. Therefore, as... Figure 12As shown, from the outside, especially from the first end of the seat post 220, only the seat belt webbing 2 extending from the seat body 210 is visible, while no components of the pretensioner 100 are visible, particularly the force transmission element 30 and the fixing element 31 of the pretensioner 100. This gives a clean and simple overall impression. Furthermore, the gas generator 22's wiring 27 can be routed from the second end of the seat post 220 if necessary. Figure 6 and Figure 7 It extends from the right side of the vehicle. Generally speaking, the first end of the seat column 220 can be the side closer to the corresponding door, while the second end can be the side closer to the center of the vehicle.

[0099] Not limited to the illustrated embodiments, in other embodiments, the force transmission element 30 and the fixing element 31 of the pretensioning device 100 may also extend from the seat column 220 and, for example, extend at an angle relative to the seat column 220 outside the seat column 220. The angle may be, for example, 45° to 125°, such as 90°.

[0100] like Figure 6 As shown, the mounting assembly may include at least one, in this case, two, first fasteners 71 configured to pass through, particularly radially through, the tube 10 of the seat column 220 and the pretensioner 100, in order to secure the pretensioner 100 to the seat column 220. The first fasteners 71 may be configured, for example, as threaded members. During installation, the first fasteners 71 may pass through the wall of the seat column 220 from the outside with their studs and be threaded to the tube 10, particularly the first tube portion 11 of the tube 10. The head of the first fastener 71 may be abutted against the outer wall of the seat column 220 by means of a washer 72. Here, the end of the stud of the first fastener 71 does not penetrate the radially opposite sidewall of the tube 10, but only extends partially in the radial dimension of the tube 10. That is, the end of the stud of the first fastener 71 may be embedded in the tube 10. Preferably, the two first fasteners 71 may be arranged radially opposite each other, passing through the seat column 220 and the tube 10 from opposite sides.

[0101] In some embodiments, such as Figure 6 and Figure 7As shown, the mounting assembly may include a limiting member 77, which may be configured for connection to the second end 14 of the tube 10, for example, by threaded connection, bonding, welding, etc. The limiting member 77 may abut against the second end side of the seat column 220. Alternatively or additionally, the axial position of the pretensioning device 100 may also be defined by a cover plate 74, which may be fixed to the second end side of the seat column 220, for example, to the seat frame 230, and the second end of the tube 10 may abut directly or indirectly against the cover plate 74. Furthermore, the cover plate 74 may also be used to cover the seat column 220 and the tube 10 at the second end side.

[0102] In some embodiments, such as Figure 13 As shown, the mounting assembly may include at least one, preferably two, second fasteners 73, which are configured to extend through the seat column 220 transversely to its extension direction. Here, the second fasteners 73 do not intersect the central axis of the seat column 220 and the body 10, but extend alongside it. These two second fasteners 73 may be located on either side of the central axis of the seat column 220 and the body 10 and are preferably parallel to each other. Therefore, the first end of the body 10 can abut against the two second fasteners 73, and the force transmission member 30 can pass between the two second fasteners. The second fasteners 73 define the axial position of the pretensioning device 100 at the first end. The axial position of the pretensioning device 100 at the second end can be defined, for example, by the limiting member 77 and / or the cover plate 74 as described above.

[0103] In some embodiments, such as Figure 14 As shown, the mounting assembly may include a third fastener 75, which may be configured to penetrate, particularly radially, the seat column 220 and the pretensioning device 100, particularly the pretensioning device 100, through the tube 10. For this purpose, a nut 76 may be threadedly connected to the third fastener 75 extending from the seat column 220 on the other side of the seat column 220. If necessary, a washer 72 may also be provided between the head of the third fastener 75 and / or the nut 76 and the outer wall of the seat column 220. Viewed axially, the third fastener 75 may be located between the second end 14 of the tube 10 and the pretensioning assembly 20. Here, the pretensioning stroke of the pretensioning assembly 20 may be defined, for example, by the distance between the third fastener 75 and the first end 13 of the tube 10. Therefore, the distance between the third fastener 75 and the first end 13 of the tube 10 may be selected such that the pretensioning device 100 still has the required pretensioning stroke.

[0104] It is understood that the various components of the installation assembly described above can be combined arbitrarily to achieve the fixation and positioning of the pretensioning device 100 in the seat column 220.

[0105] Exemplary embodiments according to this application have been described above with reference to the accompanying drawings. However, those skilled in the art will understand that various changes and modifications can be made to the exemplary embodiments of this application without departing from the spirit and scope of this application. All changes and modifications are included within the scope of protection of this application as defined by the claims. This application is defined by the appended claims, and equivalents of those claims are also included.

Claims

1. A pretensioning device (100) for a seat belt, characterized in that, The pre-tightening device includes a tube body (10), a pre-tightening assembly (20), and a force transmission element (30) connected to the pre-tightening assembly. A gas chamber (40) is formed between the pre-tightening assembly and the tube body. The gas chamber can be filled with gas to cause the pre-tightening assembly to move in the tube body along a first direction (R1), the first direction pointing from a first end (13) of the tube body to a second end (14) of the tube body. The pre-tightening assembly includes a gas generator (22) and a locking device (25). The locking device is disposed between the gas outlet (24) of the pre-tightening assembly and the first end of the tube body. Gas from the gas generator can leave the pre-tightening assembly from the gas outlet and enter the tube body. The pre-tightening device includes a gas channel penetrating the locking device. The gas channel connects the gas outlet and a first sub-chamber (43) of the gas chamber. The first sub-chamber is located between the locking device and the first end of the tube body.

2. The pretensioning device for a seat belt according to claim 1, characterized in that, The gas chamber includes a first sub-chamber and a second sub-chamber (44), the second sub-chamber being connected to the first sub-chamber via the gas channel, and the gas outlet of the pre-tightening assembly being introduced into the second sub-chamber; and / or The gas passage is formed between the locker and the inner wall of the tube and / or is formed by the locker itself; and / or The locking device is located between the first end of the tube and the gas generator; and / or During the filling of the gas chamber, the force exerted on the pre-tightening assembly by the gas in the first direction is greater than the force exerted on the pre-tightening assembly by the gas in the second direction (R2), the second direction being opposite to the first direction; preferably, during the filling of the gas chamber, the pressure-bearing area (S1) of the pre-tightening assembly in the first direction is greater than the pressure-bearing area (S2) of the pre-tightening assembly in the second direction; preferably, the pressure-bearing area of ​​the pre-tightening assembly in the first direction corresponds to the difference between the inner cross-sectional area of ​​the tube and the cross-sectional area of ​​the force transmission component; and / or The gas channel is designed to be rotationally symmetrical about the central axis of the tube.

3. The pretensioning device for a seatbelt according to claim 1 or 2, characterized in that, The locking device includes a piston (50) with a ramp (51) and a locking element (60) movable along the ramp, preferably: The piston includes a through hole, and / or the piston includes a void (56) on its outer periphery, the gas passage being at least partially formed by the through hole and / or the void; preferably, the outer diameter of the piston is substantially the same as the inner diameter of the tube body; and / or The outer diameter of the piston is smaller than the inner diameter of the tube, and the gas passage is formed at least in part by a radial gap between the piston and the tube.

4. The pretensioning device for a seat belt according to claim 3, characterized in that, The piston includes a piston head (52) facing a first end of the tube and a piston body (53) connected to the piston head. In the region where the piston head and piston body are connected, the radial dimension of the piston head is larger than the radial dimension of the piston body, preferably: The pressure-bearing area of ​​the preload assembly along the second direction includes the difference between the cross-sectional area of ​​the piston head and the cross-sectional area of ​​the piston body in the region where the piston head and piston body are interconnected; and / or Starting from the piston head, the radial dimension of the piston body increases along the first direction, and the outer circumferential surface of the piston body forms the slope. Preferably, the locking member is constructed as a sphere located between the outer circumferential surface of the piston body and the inner circumferential surface of the tube body. Preferably, the difference between the radius of the inner circumferential surface of the tube body and the radius of the end (54) of the piston body away from the piston head is less than the diameter of the sphere.

5. The pretensioning device for a seatbelt according to claim 4, characterized in that, The through hole and / or the void portion are constructed in the piston head; and / or the through hole and / or the void portion are constructed in the end region of the piston body away from the piston head; preferably, the two opposing end faces of the piston have substantially the same cross-sectional outer contour.

6. The pretensioning device for a seat belt according to any one of claims 1 to 5, characterized in that, The pre-tightening assembly includes a limiting block (21) fixedly connected to the force transmission component. The limiting block is located between the gas generator and the locking device, preferably: The preload assembly includes a sleeve (23) configured to accommodate the limiting block and the gas generator, and to fix the limiting block and the gas generator relative to each other. Preferably, the gas outlet of the preload assembly is located on the sleeve; and / or The pretensioning assembly includes a stop (26) fixedly connected to the force transmitter, and the locking device is held between the stop and the limiting block. Preferably, the locking device includes a through hole (55) through which the force transmitter extends.

7. The pretensioning device for a seat belt according to any one of claims 1 to 6, characterized in that, The first sub-chamber is sealed relative to the external space by a first seal (41), and the second sub-chamber is sealed relative to the external space by a second seal (42); and / or The force transmission element is constructed as a webbing or cable; and / or The pretensioning device includes a fixing element (31) connected to one end of the force transmission element located outside the tube body. The fixing element is configured to connect with the seat belt webbing (2). Preferably, the pretensioning device includes a bumper (15) externally disposed on a first end of the tube body. The bumper is configured to absorb the impact energy of the fixing element.

8. A vehicle seat (200), characterized in that, The vehicle seat includes a seat body (210) and a pretensioning device for the seat belt according to any one of claims 1 to 7, preferably: The pretensioning device is fixed in the seat column (220) of the vehicle seat by a mounting assembly, preferably the seat column is oriented in the lateral direction of the seat body.

9. The vehicle seat according to claim 8, characterized in that, The mounting assembly includes at least one first fastener (71), the at least one first fastener being configured to pass through the tube body of the seat column and the pretensioning device, preferably: The at least one first fastener is disposed in the region of the first end of the tube body of the pre-tightening device; and / or The mounting assembly includes two first fasteners arranged radially opposite each other.

10. The vehicle seat according to claim 8 or 9, characterized in that, The mounting assembly includes two second fasteners (73) configured to extend through the seat post transversely to its extension direction, wherein a first end of the pretensioning device's tube body abuts against the two second fasteners, and a force-transmitting element of the pretensioning device passes between the two second fasteners; and / or The mounting assembly includes a third fastener (75) configured to pass through the seat column and the pretensioning device, the third fastener being located axially between a second end of the pretensioning device tube and a pretensioning component of the pretensioning device; and / or The mounting assembly includes a limiting member (77) configured to connect to a second end of the tube body of the pre-tightening device; and / or The mounting assembly includes a cover plate (74) configured to cover the second end of the seat column and the tube and / or to limit the axial position of the tube.

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