Tensioning device for safety belt components

Abstract

The present invention relates to a tensioning device for a safety belt component, the tensioning device comprising: a gas generator (1) for generating compressed gas; a piston (2) drivable by the compressed gas; a traction cable (3) attached to the piston (2) and connectable to the safety belt component and set in tensioning movement; a tensioner tube (4) for receiving and guiding the piston (2); and a guide part (7) for the traction cable (3) arranged in at least some sections within the tensioner tube (4), the guide part (7) sealingly surrounding the traction cable (3) on its side facing the piston (2) by means of a sealing part (9), the piston (2) abutting against the guide part (7) in the starting state, the guide part (7) having a contact part (10) on its outer periphery facing the inner surface of the tensioner tube (4), the piston (2) abutting against the contact part (10) in the starting state.

Description

[Technical Field]

[0001] The present invention relates to a tensioning device for a safety belt component, the tensioning device having a gas generator for generating compressed gas, a piston drivable by the compressed gas, a traction cable attached to the piston and connected to the safety belt component for tensioning movement, and a tensioner tube for receiving and guiding the piston. [Background technology]

[0002] Such a tensioning device is known, for example, from DE 10 2015 111 083 B4, in which a piston is guided in a tensioner tube. The tensioner tube is connected to a deflection block manufactured by die casting, which forms a cable deflection means for the traction cable and forms a receptacle for a gas generator and a pressure chamber into which the compressed gas generated by the gas generator flows. The use of a deflection block connected to the end face of the tensioner tube requires components that are relatively expensive to manufacture and require a relatively large amount of space.

[0003] Thus, WO 2021 / 160 569 A1 discloses a tensioning device in which a gas generator is arranged within a straight tensioner tube. A recess is formed in the side of the tensioner tube, through which the traction cable is guided out of the tensioner tube. To guide the traction cable out of the tensioner tube, a cable deflection means is disclosed that is designed in several parts. A component called a guide part, which has a receptacle for the gas generator, can be inserted into the tensioner tube, and a component called a fixing part protrudes from the outside through the recess so that the traction cable is guided through the recess by the fixing part (hereinafter also referred to as a cable guide).

[0004] The guide part has a seal at its end facing the piston that seals and surrounds the traction cable so that, during operation, compressed gas cannot escape along the traction cable through the guide part and the cable guide. The seal also serves as an abutment / stop for the piston when assembling the tensioning device. During assembly, the piston is brought into contact with the seal of the guide part, which thereby provides a predetermined position for the piston. Thus, according to WO 2021 / 160 569 A1, the seal performs two functions: sealing the pressure chamber and providing a stop. However, if the piston stops against the seal during assembly, this could damage the seal and thus impair the sealing function. Furthermore, if the seal is elastic, the position of the piston in the initial state of the tensioning device is not precisely specified. Summary of the Invention

[0005] It is therefore an object of the present invention to at least partially eliminate the drawbacks described with respect to the prior art, in particular to provide a tensioning device in which the escape of compressed gas is reduced and / or the position of the piston in the initial state is more accurately specified.

[0006] A possible solution to this problem is provided by a tensioning device having the features of claim 1, further solutions and advantageous developments are outlined above and below in the description and in the dependent claims, the individual features of the advantageous developments being able to be combined with one another in a technically rational way.

[0007] This object is achieved in particular by a tensioning device for a safety belt component having the characteristics mentioned at the outset, in which a guide part is arranged at least partly, preferably entirely, in the tensioner tube, the guide part sealingly enclosing the traction cable by means of a sealing part on the side facing the piston, and furthermore, the guide part has a contact part on its outer periphery facing the inner surface of the tensioner tube, and the piston abuts against the contact part in the initial state.

[0008] In other words, the basic concept of the present invention provides that the integral guide section has two parts arranged at a distance from each other, where the first part, called the sealing part, provides a sealing function for the traction cable, and the second part, called the contact part, provides a stop function for specifying the position of the piston in the initial state. In particular, it is provided that the contact part is offset radially outward (with respect to the longitudinal axis of the tensioner tube) with respect to the sealing part that surrounds the traction cable in the center of the tensioner tube. By separating the sealing and stop functions in different parts of the guide section, on the one hand, the risk of compressed gas leakage is reduced, and on the other hand, a more accurate stop is specified for the piston in the initial state.

[0009] In order to more accurately specify the position of the contact portion when the guide portion is inserted into the tensioner tube, it is proposed that the contact portion of the guide portion abuts the inner surface of the tensioner tube in the initial state. Therefore, the contact portion of the guide portion is sized so that it contacts the inner surface of the tensioner tube in the initial state. If the contact portion is placed inside the tensioner tube, the contact portion cannot deform radially outward when the piston is assembled.

[0010] In principle, the piston and the guide part must be geometrically compatible so that the piston can initially contact the contact part. For this purpose, it is possible, for example, to provide that the piston has a sleeve-shaped part that extends radially outward in the axial direction, in particular beyond the seal. In this case, the sleeve-shaped part of the piston surrounds the seal. However, it is preferred that the contact part protrudes axially beyond the seal in the direction of the piston, so that the contact point between the piston and the contact part is axially offset relative to the seal. In this case, the region of the guide part that forms the contact part surrounds the seal.

[0011] In principle, it is sufficient for the seal to form a few discrete contact points with the piston, however, it is preferred that the seal is shaped so as to form a self-contained annular contact point for the piston.

[0012] To further ensure that the sealing function of the seal is not impaired by the piston, one embodiment provides that in the initial state, the seal is preferably spaced axially by at least 1 mm, particularly preferably by at least 3 mm, from the part of the piston that directly surrounds the traction cable. Thus, the piston typically has a mushroom-shaped design, with a tubular central section that surrounds the traction cable and extends along the traction cable toward the seal. The end face of this tubular section of the piston that faces the seal is clearly spaced from the seal of the guide in the initial state, while the mushroom-shaped region of the piston abuts against the contact part of the guide.

[0013] The invention relates in particular to a tensioning device in which the tensioner tube has a recess on its side between the gas generator and the piston, and the tensioning device comprises a cable guide which protrudes through the recess into the tensioner tube, by means of which the traction cable is guided through the recess, which means that a die-cast deflection block is no longer required.

[0014] It is particularly provided that the cable guide engages in the guide part by its part engaging in the tensioner tube, whereby, on the one hand, the guide part is fixed in a predetermined position within the tensioner tube and, on the other hand, the traction cable can pass through the recess without coming into contact with the edge of the recess formed by the tensioner tube.

[0015] The gas generator is arranged in particular in the tensioner tube, and it can be preferably provided that the guide part has a receptacle, and the gas generator is arranged in the receptacle, in this connection it is particularly provided that the guide part is designed in such a way that the compressed gas generated by the gas generator is guided to the piston along the traction cable inside the tensioner tube without acting on the traction cable in the area of ​​the guide part.

[0016] The recesses for the traction cable and the cable guide are arranged in particular in straight sections of the tensioner tube, in particular provided that the tensioner tube is straight over its entire extent. [Brief explanation of the drawings]

[0017] The invention and the technical environment will now be described by way of example with reference to the figures, which show, in a simplified manner: [Figure 1] FIG. 2 is an exploded view of the tensioning device. [Figure 2] 1 is a cross-sectional view taken along the longitudinal axis of a tensioner tube through a tensioning device; [Figure 3] Detail of a cross-sectional view of a tensioning device. DETAILED DESCRIPTION OF THE INVENTION

[0018] The tensioning device shown in Figures 1 and 2 comprises a tensioner tube 4 and a traction cable 3 for a safety belt component. The tensioner tube 4 is formed with a recess 5 through which the traction cable 3 is guided by a cable guide 6. In the tensioner tube 4, a piston 2 is arranged on the traction cable 3, and a fastening means 8 is pressed by the traction cable 3 and abuts against the piston 2. The tensioner tube 4 also has a guide part 7 which forms a receptacle for a gas generator 1. In the assembled state, the gas generator 1 is therefore also arranged in the tensioner tube 4.

[0019] As can be seen in particular from FIG. 2, the cable guide 6 engages in the guide part 7 in the assembled state, through which the traction cable 3 is guided.

[0020] During operation, the gas generator 1 generates compressed gas, which is guided along the traction cable 3 through the guide part 7 to the piston 2 without coming into contact with the traction cable 3. As a result of the compressed gas, the piston 2 is driven (to the right in Figure 2) and rests, with its end facing away from the gas generator 1, on the fastening means 8. The tensioning device can thus be used to retract safety belt components (such as end attachments or belt buckles) which may be connected to the traction cable.

[0021] As can be seen in particular from Figure 3, the guide part 7 has a sealing part 9 that sealingly surrounds the traction cable 3. The sealing part 9 therefore prevents the compressed gas from being able to escape along the traction cable 3 in the direction of the cable guide 6 and thus through the recess 5 to the environment. The guide part 7 also has a contact part 10 that abuts the inside of the tensioner tube 4 and protrudes beyond the sealing part 9 in the direction of the piston 2.

[0022] In the assembled state, the piston 2 abuts against the contact portion 10 of the guide portion 7, and the tubular portion of the piston 2 which directly surrounds the traction cable 3 is sized such that its front end is spaced apart from the sealing portion 9. By forming both the sealing portion 9 and the contact portion 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 traction cable 3 and on the other hand allows a more precisely designated stop for the piston 2. [Explanation of symbols]

[0023] 1 gas generator 2 pistons 3 Towing Cable 4 Tensioner tube 5 recess 6 Cable guide 7 Guide section 8 Fastening means 9 Sealing part 10 Contact part

Claims

1. 1. A tensioning device for a safety belt component, comprising: a gas generator (1) for generating pressurized gas; - a piston (2) that can be driven by said pressurized gas; a traction cable (3) connected to said piston (2) and capable of being connected to a safety belt component to cause tensioning movements; - a tensioner tube (4) for receiving and guiding said piston (2); a guide (7) for the traction cable (3), which is arranged at least partially inside the tensioner tube (4) and which sealingly surrounds the traction cable (3) on the side facing the piston (2) by means of a seal (9); and The piston (2) abuts against the guide portion (7) in an initial state, the guide portion (7) has a contact portion (10) on its outer periphery facing the inner surface of the tensioner tube (4), and the piston (2) abuts against the contact portion (10) in the initial state. Tension device.

2. 2. A tensioning device according to claim 1, wherein the contact portion (10) projects axially beyond the sealing portion (9) in the direction of the piston (2).

3. 3. A tensioning device according to claim 1 or 2, wherein in the initial state, the sealing portion (9) is axially spaced from the part of the piston (2) that immediately surrounds the traction cable (3).

4. The tensioning device according to any one of claims 1 to 3, wherein the contact portion (10) of the guide portion (7) abuts against the inner surface of the tensioner tube (4) in the initial state.

5. 5. The tensioning device according to claim 1, wherein the tensioner tube (4) has a recess (5) on the side between the gas generator (1) and the piston (2), and the tensioning device comprises a cable guide (6) that protrudes into the tensioner tube (4) through the recess (5), and the cable guide (6) allows the traction cable (3) to be pulled out of the tensioner tube (4) through the recess (5).

6. 6. A tensioning device according to claim 5, wherein the cable guide (6) is engaged with the guide part (7).

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

8. Tensioning device according to any one of claims 5 to 7, wherein the recess (5) is arranged on a straight section of the tensioner tube (4).

9. A tensioning device according to any one of claims 1 to 8, wherein the tensioner tube (4) is straight throughout its extent.

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