Tensioning device for a safety belt component

Abstract

The invention relates to a tensioning device for a safety belt component, having a gas generator (1) for generating a compressed gas, a piston (2) which is driveable by the compressed gas, a traction cable (3) which is attached to the piston (2) and is connectable to a safety belt component to be set into a tensioning movement, a tensioner tube (4) for receiving and guiding the piston (2), a guide part (7) which is arranged at least in some sections in the tensioner tube (4) and is for the traction cable (3), the guide part (7) sealingly surrounding the traction cable (3) on its side facing the piston (2) with a sealing portion (9), the piston (2) in a starting state bearing against the guide part (7), the guide part (7) having a contact portion (10) on its outer circumference facing an inner surface of the tensioner tube (4), and the piston (2) in the starting state bearing against the contact portion (10).

Description

[0001] Tensioning device for a seat belt component

[0002] The present invention relates to a tensioning device for a safety belt component, comprising a gas generator for generating a compressed gas, a piston which can be driven by the compressed gas, a pull cable which is connected to the piston and which can be connected to a safety belt component which is to be set in a tensioning movement, and a tensioning tube for receiving and guiding the piston.

[0003] Such a tensioning device is known, for example, from DE 10 2015 1 1 1 083 B4, in which the piston is guided in a tensioning tube. The tensioning tube is connected to a deflection block manufactured using a die-casting process, which forms a cable deflection for the traction cable, a receptacle for the gas generator, and a pressure chamber into which the compressed gas generated by the gas generator flows. The deflection block, connected to the front of the tensioning tube, requires a relatively expensive component that also requires a relatively large amount of space.

[0004] Therefore, WO 2021 / 160 569 A1 discloses a tensioning device in which the gas generator is arranged within the rectilinear tensioning tube. A recess is formed in the casing of the tensioning tube, through which the traction cable is guided out of the tensioning tube. For guiding the traction cable out of the tensioning tube, a cable deflection device is disclosed, which is constructed in several parts. A component referred to as the guide part, with a receptacle for the gas generator, can be inserted into the tensioning tube, and a component referred to as the fixing part protrudes from the outside through the recess, so that the traction cable is guided through the recess by means of the fixing part, also referred to below as the cable guide.

[0005] At its end facing the piston, the guide part has a sealing section which seals around the pull cable so that, in the event of activation, no compressed gas can escape through the guide part and the cable guide along the pull cable. The sealing section also serves as a stop for the piston during assembly of the tensioning device. During assembly, the piston is brought into contact with the sealing section of the guide part so that a predefined position for the piston is provided by the sealing section. Thus, according to WO 2021 / 160 569 A1, the sealing section performs two functions: sealing the pressure chamber and providing a stop. However, if the piston hits the sealing section during assembly, this can damage the sealing section, thus impairing its sealing function.In addition, if the sealing section is designed to be elastic, the position of the piston in the initial state of the tensioning device is not precisely specified.

[0006] The object of the present invention is therefore to at least partially eliminate the disadvantages explained with reference to the prior art and in particular to provide a tensioning device in which the escape of compressed gas is reduced and / or in which the position of the piston in the initial state is specified more precisely.

[0007] A possible solution to the problem is specified with the tensioning device having the features of claim 1, wherein further solutions and advantageous developments of the tensioning device are explained in the preceding and following description and in the subclaims, wherein individual features of the advantageous developments can be combined with one another in a technically expedient manner.

[0008] The object is achieved in particular by a tensioning device for a safety belt component having the features mentioned above, wherein a guide part is arranged at least partially, preferably completely, in the tensioning tube, and the guide part sealingly encloses the traction cable on its side facing the piston with a sealing section. Furthermore, it is provided that the guide part has a contact section on its outer circumference facing an inner surface of the tensioning tube, wherein the piston rests against the contact section in the initial state.

[0009] In other words: the basic idea of ​​the invention is that the one-piece guide part has two sections arranged separately from one another, so that the first section, referred to as the sealing section, provides the sealing function with respect to the pull cable and the second section, referred to as the contact section, provides the function of a stop for specifying a position of the piston in the initial state. In particular, it is provided that the contact section is offset outwards in the radial direction (relative to the longitudinal axis of the tensioner tube) relative to the sealing section, which encloses the pull cable centrally in the tensioner tube. By separating the function of providing a seal and the provision of a stop at different sections of the guide part, on the one hand the risk of compressed gas leakage is reduced and on the other hand a more precise stop for the piston in the initial state is specified.

[0010] To more precisely specify the position of the contact section when the guide part is inserted into the tensioner tube, it is proposed that the contact section of the guide part rests against the inner surface of the tensioner tube in the initial state. The contact section of the guide part is therefore dimensioned so that it is in contact with the inner surface of the tensioner tube in the initial state. If the contact section rests against the inner surface of the tensioner tube, the contact section cannot be deformed radially outward when the piston is installed.

[0011] In principle, the geometry of the piston and the guide part must be coordinated so that the piston can come into contact with the contact section in the initial state. For this purpose, it can be provided, for example, that the piston has a sleeve-shaped section which extends in particular radially outwards in the axial direction over the sealing section. In this case, the sleeve-shaped section of the piston would surround the sealing section. However, it is preferred that the contact section protrudes in the axial direction over the sealing section in the direction of the piston, so that the contact point between the piston and the contact section is offset in the axial direction to the sealing section. In this case, the region of the guide part forming the contact section surrounds the sealing section.

[0012] In principle, it is sufficient for the sealing section to form several discrete contact points for the piston. However, it is preferred that the sealing section be shaped to form a self-contained, annular contact point for the piston.

[0013] In order to ensure even more successfully that the sealing function of the sealing section is not impaired by the piston, one embodiment provides that the sealing section, in the initial state, is spaced apart in the axial direction from a section of the piston which directly encloses the pull cable, preferably by at least 1 mm, particularly preferably at least 3 mm. The piston therefore generally has a mushroom-shaped configuration, with a tubular central section enclosing the pull cable and extending along the pull cable in the direction of the sealing section. The end of this tubular section of the piston facing the sealing section is, in the initial state, significantly spaced apart from the sealing section of the guide part, while the piston rests with its mushroom-shaped region against the contact section of the guide part.

[0014] The invention relates in particular to tensioning devices in which the tensioning tube has a recess in its casing between the gas generator and the piston, and in which the tensioning device comprises a cable guide which projects through the recess into the tensioning tube and with which the pull cable is guided through the recess. This makes it possible to dispense with the deflection block produced by die casting. In particular, it is provided that the cable guide engages in the guide part with its section engaging in the tensioning tube, whereby on the one hand the guide part is fixed in its position in the tensioning tube and on the other hand a passage of the pull cable through the recess is made possible without the pull cable coming into contact with an edge of the recess formed by the tensioning tube.

[0015] The gas generator is arranged, in particular, within the tensioner tube. Preferably, the guide part may have a receptacle, with the gas generator being arranged in the receptacle. In this context, it is particularly provided that the guide part is designed such that the compressed gas generated by the gas generator is guided along the pull cable within the tensioner tube to the piston, without the compressed gas being applied to the pull cable in the region of the guide part.

[0016] The recess for the traction cable and the cable guide is arranged in particular in a rectilinear section of the tensioning tube, wherein it is provided in particular that the tensioning tube is rectilinear over its entire extent.

[0017] The invention and the technical environment are explained below using the figures as examples. They show schematically

[0018] Figure 1 : an exploded view of a tensioning device,

[0019] Figure 2: a sectional view along the longitudinal axis of a

[0020] tensioner tube through the tensioning device and

[0021] Figure 3 : a detailed view through the tensioning device in the

[0022] Sectional view.

[0023] The tensioning device shown in Figures 1 and 2 comprises a tensioner tube 4 and a pull cable 3 for a seat belt component. A recess 5 is formed in the tensioner tube 4, through which the pull cable 3 is guided by means of a cable guide 6. Within the tensioner tube 4, a piston 2 is arranged on the pull cable 3, with a fastening 8 being pressed onto the pull cable 3 and resting against the piston 2. Also arranged within the tensioner tube 4 is a guide part 7, which forms a receptacle for a gas generator 1. In the assembled state, the gas generator 1 is thus also arranged in the tensioner tube 4.

[0024] As can be seen in particular from Figure 2, the cable guide 6 engages in the guide part 7 in the assembled state, the traction cable 3 being guided through the guide part 7.

[0025] When triggered, the gas generator 1 generates a pressurized gas, which is guided through the guide part 7 along the traction cable 3 to the piston 2 without coming into contact with the traction cable 3. The pressurized gas drives the piston 2 (to the right in Figure 2), with the piston 2 resting against the fastening 8 at its end facing away from the gas generator 1. The tensioning device can therefore be used to retract a safety belt component (such as an end fitting or belt buckle) that can be connected to the traction cable.

[0026] As can be seen particularly from Figure 3, the guide part 7 has a sealing section 9 that seals around the traction cable 3. The sealing section 9 thus prevents compressed gas from escaping along the traction cable 3 in the direction of the cable guide 6 and thus through the recess 5 into the environment. The guide part 7 also has a contact section 10 that rests against an inner side of the tensioner tube 4 and protrudes beyond the sealing section 9 in the direction of the piston 2.

[0027] In the assembled state, the piston 2 rests against the contact section 10 of the guide part 7, wherein a tubular section of the piston 2 directly surrounding the pull cable 3 is dimensioned such that its front end is spaced from the sealing section 9. By forming both a sealing section 9 and a contact section 10, the functions of sealing and providing a stop for the piston 2 are separated, which on the one hand provides a better seal for the pull cable 3 and on the other hand provides a more precise stop for the piston 2.

[0028] List of reference symbols

[0029] 1 gas generator

[0030] 2 pistons

[0031] 3 pull rope

[0032] 4 tensioner tube

[0033] 5 Recess

[0034] 6 Rope guide

[0035] 7 Guide part

[0036] 8 Fastening

[0037] 9 Sealing section

[0038] 10 Plant section

Claims

Claims 1. A tensioning device for a safety belt component, comprising a gas generator (1) for generating a compressed gas, a piston (2) which can be driven by the compressed gas, a traction cable (3) connected to the piston (2) and which can be connected to a safety belt component which is to be set in a tensioning movement, a tensioning tube (4) for receiving and guiding the piston (2), a guide part (7) for the traction cable (3) which is arranged at least in sections in the tensioning tube (4), wherein the guide part (7) sealingly encloses the traction cable (3) on its side facing the piston (2) with a sealing section (9), wherein the piston (2) bears against the guide part (7) in an initial state, characterized in that the guide part (7) has a contact section (10) on its outer circumference facing an inner surface of the tensioning tube (4), and in that the piston (2) bears against the contact section (10) in the initial state.

2. Tensioning device according to claim 1, wherein the contact section (10) projects in the axial direction beyond the sealing section (9) in the direction of the piston (2).

3. Tensioning device according to one of the preceding claims, wherein the sealing section (9) in the initial state is Pull cable (3) is spaced in the axial direction from the section of the piston (2) immediately surrounding it.

4. Tensioning device according to one of the preceding claims, wherein the contact section (10) of the guide part (7) in the initial state rests against the inner surface of the tensioning tube (4).

5. Tensioning device according to one of the preceding claims, wherein the tensioning tube (4) between the gas generator (1) and the piston (2) has a recess (5) in its casing and wherein the tensioning device comprises a cable guide (6) which projects through the recess (5) into the tensioning tube (4) and with which the traction cable (3) is guided out of the tensioning tube (4) through the recess (5).

6. Tensioning device according to claim 5, wherein the cable guide (6) engages in the guide part (7).

7. Tensioning device according to claim 5 or 6, wherein the guide part (7) has a receptacle and wherein the gas generator (1) is arranged in the receptacle.

8. Tensioning device according to one of claims 5 to 7, wherein the recess (5) is arranged in a rectilinear section of the tensioning tube (4).

9. Tensioning device according to one of the preceding claims, wherein the tensioning tube (4) is linear over its entire extent.

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