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, comprising 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 effecting a tension movement, and a tensioner tube for receiving and guiding the piston.

Background Art

[0002] Such a tensioning device is known, for example, from German Patent Application Publication No. 10 2015 111 083 (B4), in which the piston is guided within a tensioner tube. The tensioner tube is connected to a deflection block produced by die-casting, which forms cable deflection means for the traction cable and forms a receptacle for the 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 is relatively expensive to manufacture and also requires components that take up a relatively large amount of space.

[0003] Therefore, International Publication No. 2021 / 160 569 (A1) discloses a tensioning device in which the gas generator is arranged within a linear tensioner tube. A recess is formed in the side surface of the tensioner tube, through which the traction cable is guided out of the tensioner tube. Cable deflection means designed in several parts are disclosed for guiding the traction cable out of the tensioner tube, called guide parts, and a component having a receptacle for the gas generator can be inserted into the tensioner tube, and a component called a fixing part projects through the recess from the outside such that the traction cable is guided through the recess by the fixing part (hereinafter also called a cable guide).

[0004] The guide section has a sealing section at its end facing the piston, which seals and surrounds the traction cable to prevent compressed gas from escaping through the guide section and cable guide along the traction cable during operation. The sealing section also functions as a contact / stopping section for the piston when assembling the tensioning device. During assembly, the piston is brought into contact with the sealing section of the guide section, thereby the sealing section provides a predetermined position for the piston. Thus, according to International Publication No. 2021 / 160 569(A1), the sealing section performs two functions: sealing the pressure chamber and providing a stopping section. However, if the piston stops against the sealing section during assembly, this may damage the sealing section and thus impair its sealing function. Furthermore, if the sealing section is elastic, the position of the piston in the initial state of the tensioning device is not precisely specified. [Overview of the project]

[0005] Therefore, an object of the present invention is to eliminate, at least partially, the drawbacks described in relation 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 precisely specified.

[0006] A possible solution to this problem is provided by a tensioning device having the features of claim 1, and further solutions and advantageous developments are outlined in the above and below descriptions and dependent claims, and the individual features of the advantageous developments can be combined with each other in a technically reasonable manner.

[0007] This objective is achieved, in particular, by a tensioning device for a safety belt component having the features described at the beginning, wherein at least partially, preferably entirely, a guide portion is located within the tensioner tube, and the guide portion surrounds and seals the traction cable with a sealing portion on the side facing the piston. Furthermore, the guide portion has a contact portion on its outer circumference facing the inner surface of the tensioner tube, and the piston is provided to contact the contact portion in its initial state.

[0008] In other words, the basic concept of the present invention is to provide a guide portion having two parts spaced apart from each other, where a first part called a sealing portion provides a sealing function for the traction cable, and a second part called a contact portion provides a stopping portion for specifying the position of the piston in the initial state. In particular, the contact portion is provided to be radially offset outward (with respect to the longitudinal axis of the tensioner tube) from the sealing portion that surrounds the traction cable at the center of the tensioner tube. By separating the function of providing sealing and the function of providing stopping in different parts of the guide portion, the risk of compressed gas leakage is reduced on the one hand, and a more precise stopping position of the piston in the initial state is specified on the other hand.

[0009] To more precisely 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 against the inner surface of the tensioner tube in its initial state. Therefore, the contact portion of the guide portion is sized to contact the inner surface of the tensioner tube in its initial state. When the contact portion is positioned inside the tensioner tube, it cannot deform radially outward when the piston is assembled.

[0010] In principle, the piston and the guide portion must have matching shapes so that the piston can contact the contact portion in its initial state. For this purpose, for example, the piston may have a sleeve-shaped portion that extends radially outward in the axial direction, particularly beyond the sealing portion. In this case, the sleeve-shaped portion of the piston surrounds the sealing portion. However, it is preferable that the contact portion protrudes axially beyond the sealing portion in the direction of the piston, and the contact point between the piston and the contact portion is offset axially with respect to the sealing portion. In this case, the region of the guide portion forming the contact portion surrounds the sealing portion.

[0011] In principle, it is sufficient for the sealing portion to form several discrete contact points with respect to the piston. However, it is preferable that the sealing portion be molded to form a self-contained annular contact point for the piston.

[0012] To further ensure that the sealing function of the sealing portion is not impaired by the piston, one embodiment provides that, in the initial state, the sealing portion is axially spaced at least 1 mm, and particularly preferably at least 3 mm, from the portion of the piston that directly surrounds the traction cable. Thus, the piston typically has a mushroom-shaped design, with a tubular central portion surrounding the traction cable and extending along the traction cable toward the sealing portion. In the initial state, the end face of this tubular portion of the piston facing the sealing portion is clearly spaced away from the sealing portion of the guide portion, while the piston has its mushroom-head shaped region in contact with the contact portion of the guide portion.

[0013] The present 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 that protrudes into the tensioner tube through the recess, by which the traction cable is guided through the recess. This means that a die-cast deflection block is no longer required.

[0014] The cable guide is particularly provided to engage with the guide portion by the portion that engages with the tensioner tube, thereby, on the one hand, the guide portion is fixed in place within the tensioner tube, and on the other hand, the traction cable can pass through the recess without contacting the edge of the recess formed by the tensioner tube.

[0015] The gas generator is preferably provided to be located within the tensioner tube, and the guide section preferably has a receptacle, with the gas generator located within the receptacle. In this regard, the guide section is preferably provided to be designed so 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 region of the guide section.

[0016] Recesses for the traction cable and cable guide are provided, in particular, in the straight portion of the tensioner tube, and in particular the tensioner tube is provided to be straight throughout its entire length. [Brief explanation of the drawing]

[0017] The present invention and its technical environment will be described below with reference to the figures. The figures schematically show the following. [Figure 1] This is an exploded view of a tensioning device. [Figure 2] A cross-sectional view of the tensioner tube along its longitudinal axis through the tensioning device. [Figure 3] This is a detailed cross-sectional view of the tensioning device. [Modes for carrying out the invention]

[0018] The tensioning device shown in Figures 1 and 2 comprises a tensioner tube 4 and a traction cable 3 for the safety belt components. A recess 5 is formed in the tensioner tube 4, and the traction cable 3 is guided through the recess 5 by a cable guide 6. Within the tensioner tube 4, a piston 2 is positioned on the traction cable 3, and a fastening means 8 is pressed against the piston 2 by the traction cable 3. The tensioner tube 4 also contains a guide section 7 that forms a receptacle for the gas generator 1. Therefore, in the assembled state, the gas generator 1 is also positioned within the tensioner tube 4.

[0019] As can be seen in particular from Figure 2, the cable guide 6 engages with the guide section 7 when assembled, and the traction cable 3 is guided through the guide section 7.

[0020] During operation, the gas generator 1 generates compressed gas, which is guided through the guide portion 7 along the traction cable 3 to the piston 2 without contacting the traction cable 3. As a result of the compressed gas, the piston 2 is driven (to the right in FIG. 2), and the piston 2 is placed on the fastening means 8 at its end facing outward from the gas generator 1. Thus, the tensioning device can be used to draw in a safety belt component (such as an end fitting or a belt buckle) that can be connected to the traction cable.

[0021] As can be seen particularly from FIG. 3, the guide portion 7 has a sealing portion 9 that seals and surrounds the traction cable 3. Thus, the sealing portion 9 prevents the compressed gas from escaping along the traction cable 3 in the direction of the cable guide 6 and thus through the recess 5 to the environment. The guide portion 7 also has a contact portion 10 that abuts against the inside of the tensioner tube 4 and projects beyond the sealing portion 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 that 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 sealing function and the function of providing a stop for the piston 2 are separated, whereby, on the one hand, better sealing for the traction cable 3 is provided, and on the other hand, the stop for the piston 2 is more accurately specified.

Explanation of Reference Numerals

[0023] 1 Gas generator 2 Piston 3 Traction cable 4 Tensioner tube 5 Recess 6 Cable guide 7 Guide portion 8 Fastening means 9 Sealing portion 10 Contact portion

Claims

1. A tensioning device for a safety belt component, - A gas generator (1) for generating pressurized gas, - A piston (2) that can be driven by the pressurized gas, - A traction cable (3) connected to the piston (2) and capable of being connected to a safety belt component to transfer tension, - A tensioner tube (4) for receiving and guiding the piston (2), - A guide portion (7) for the traction cable (3), which is at least partially located within the tensioner tube (4) and surrounds the traction cable (3) by sealing portion (9) on the side facing the piston (2), It has, The piston (2) in its initial state contacts the guide portion (7), The guide portion (7) has a contact portion (10) on its outer circumference facing the inner surface of the tensioner tube (4), and the piston (2) is characterized in that it abuts against the contact portion (10) in the initial state. Tension device.

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

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

4. The tensioning device according to claim 1, wherein the contact portion (10) of the guide portion (7) is in contact with the inner surface of the tensioner tube (4) in the initial state.

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

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

7. The tensioning device according to claim 5, wherein the guide portion (7) has a receptacle and the gas generator (1) is disposed within the receptacle.

8. The tensioning device according to claim 5, wherein the recess (5) is located on the straight portion of the tensioner tube (4).

9. The tensioning device according to claim 1, wherein the tensioner tube (4) is linear over its entire length.

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