Tensioner device for a motor seat vehicle seat belt with a guide element

A tensioner device for a seat belt with a tensioner block (1) cable passageway (2) in which there is formed a pressure chamber (3) and a pull cable (4) that can be connected to a compressed-gas powered piston and that can be connected to a seat belt component for providing a tensioning motion. The pull cable extends through the pressure chamber (3) and with a gas generator (5) that is attached to the tensioner block (1), wherein, when triggered, the gas exiting from the gas generator (5) flows through a feed section (6) of the tensioner block (1) into the pressure chamber (3), wherein a guide element (8) is formed in a transition area (7) of the feed section (6) in the pressure chamber (3) that extends via a bar (11) parallel relative to the pull cable (4) and thereby divides the transition area (7) into at least two openings (9).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase application of PCT International Application No. PCT/EP2017/055404, filed Mar. 8, 2017, which claims the benefit of priority under 35 U.S.C. § 119 to German Patent Application No. 10 2016 104 226.9, filed Mar. 8, 2016, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to a tensioner device for a motor vehicle seat belt (also referred to as a pretensioner device or, more specifically, a linear pretensioner) with a tensioner block that forms a cable passageway, in which there is formed a pressure chamber that follows the cable deflection, and a pull cable that can be connected to a compressed-gas powered piston and that can be connected to a seat belt component that is driven to undergo a tensioning motion. The pull cable enters, the pressure chamber and extends through the pressure chamber and with a gas generator that is attached to the tensioner block, wherein, when triggered, the gas exiting from the gas generator flows through a feed section of the tensioner block into the pressure chamber.

BACKGROUND

A tensioner device with the characteristics as specified above, is generally known in the art from DE 10 2014 105 446 A1 which provides an opening region inside a sealing support to prevent any direct contact of the gas exiting from the gas generator with the pull cable by redirecting the gas at least in part after the gas generator has been triggered. Any direct contact of the gas with the pull cable can weaken the pull cable, which is why the pull cable must be dimensioned accordingly. It is therefore desirable that those tensioner devices that do not include a sealing support as described in DE10 2014 105 446 A1 at least reduce the direct admission of gas that acts on the pull cable.

A further tensioner device is known from DE 10 696 26 094 T2.

SUMMARY AND INTRODUCTORY DESCRIPTION OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide a tensioner device that offers at least a partial solution for the above-mentioned problems. Specifically, the invention envisions a tensioner device that will weaken the pull cable to a lesser degree during the triggering process.

The above-stated object is achieved with tensioner devices that have the characteristics as specified in the following description.

The above-stated object is addressed by providing a tensioner device where a guide element is implemented in a transition area from the feed section in the pressure chamber for example in the form of a bar, parallel relative to the pull cable, which divides the transition area into at least two openings.

In this solution, when triggered, the bar forms a shadow area relative to the gas, where the pull cable is disposed. Ideally, the bar divides the gas flow that arrives from the feed section in two partial flows, each of which is guided around the pull cable. This means that no major gas flow component will come in direct contact with the pull cable inside the pressure chamber. To advantageously subdivide the flow into two partial flows, it is provided particularly that a width of the bar increases from the feed section to the pressure chamber.

Another solution for the above-mentioned object envisions providing a tensioner device where a guide element is implemented in a transition area from the feed section to the pressure chamber that extends into the transition area and laterally delimits the transition area and that is formed by a deflection area for deflecting the inflowing gas which is directed toward the feed section.

In an embodiment of the invention, a wall extends in the region of the transition area and into the transition area, whereby a flow direction of a substantial part of the gas flow in the feed section is deflected by the protruding wall that forms the guide element, wherefore the deflected part of the gas will not make contact with the pull cable until after an extended flow distance, if at all. While traversing this extended flow distance, the deflected gas can cool down, and accordingly, the weakening effect of the gas on the pull cable is lessened. The deflection area that is directed towards the feed section is therefore configured, particularly, with curved radii that ensure a corresponding deflection.

A solution according to the invention provides that the guide element extends from a side that is directed toward the cable deflection in the direction of extension of the pull cable into the transition area. This means, on the side of the cable passageway, the transition area has a deflection area that is directed toward the feed section and designed such that at least a part of the inflowing gas from the feed section is deflected in the direction of the piston-side end of the pressure chamber. The gas that is deflected in this manner will come into contact with the pull cable in a cooled state, if at all. Moreover, by deflecting the gas, the area of the pull cable where the gas meets the pull cable is enlarged, whereby the weakening influence of the gas is reduced.

A further solution according to the invention provides that the guide element extends from a side that is transverse relative to an extension direction of the pull cable all the way to a cover of the pull cable in the transition area. By such a cover of the pull cable it is intended that at least a part of the inflowing gas is deflected in the circumferential direction around the pull cable. The pull cable is therefore in a shadow area of the guide element that protrudes from one side into the transition area.

The functioning of a tensioner device and of individual components of the tensioner device has been described previously in the introduction in DE 10 2014 105 446 A1 and in EP 2 082 926 B1; we refer to these citations in their entirety. The tensioner device includes, particularly, a tensioner tube for receiving and guiding a compressed-gas powered piston that is connected to the pull cable.

According to an embodiment of the invention, the guide element is designed in one piece with the tensioner block. The guide element is formed already in the production stage of the tensioner block, for example, by means of a zinc die-cast process.

In the alternative, the guide element can be inserted in the tensioner block as an independent component. This way, it is possible to apply the invention to preexisting tensioner blocks.

DETAILED DESCRIPTION

FIG. 1is a longitudinal section of the tensioner block1of a tensioner device according to the prior art. On the right side, the tensioner block1forms a cable passageway2through which extends a pull cable4. The pull cable4is depicted on the right side inFIG. 1and can be connected to a seat belt component such as a belt latch plate, buckle or anchorage. The pull cable4extends to the left through a pressure chamber3that is formed inside the tensioner block1and connected to a piston on the left side (not shown). In addition, a gas generator5is disposed on the tensioner block1from which, when triggered, gas flows into a feed section6that is formed on the tensioner block1. In a transition area7, the feed section6transitions into the pressure chamber6. Although tensioner block1forms a cable deflection in the illustrated embodiment, certain implementations can have pull cable4extending in a linear manner from pressure chamber3.

When triggered, the hot gas exits from the gas generator6into the feed section6and flows through the transition area7and into the pressure chamber3where it makes direct contact with the pull cable4. The pull cable4may structurally weakened by coming into direct contact with the hot gas. The gas then flows further through the pressure chamber3and acts upon the piston that is attached to the pull cable4(not shown), whereby the pull cable4and accordingly the seat belt component that is connected to the pull cable4(not shown) are displaced.

In an embodiment of the present invention a guide element8is formed in the transitional area7between the feed section6and the pressure chamber3.

According to the embodiment inFIG. 2, the guide element8is designed as a bar11that extends parallel relative to the pull cable4. The bar11creates two openings9. The bar11has an increasing width from the feed section6to the pressure chamber3.

Due to the guide element8that is formed via the bar11, the gas flow that is present in the feed section6is subdivided in two partial flows that flow past or around the pull cable4in as much as possible and/or do come into contact with the pull cable at a direct large impact angle relative to a normal direction impact). Rather, the pull cable4is disposed in the shadow area of the bar11. This means the bar11reduces the possible erosive effect of exposure of the pull cable4to direct gas flow from the gas generator5.

Wherein the bar11as shown inFIG. 2is designed in one piece with the tensioner block1(i.e. integrated into the block),FIG. 3provides, in contrast, that the guide element8may be provided as an independent component. The guide element8forms a bar11that delimits two openings9. This means that the guide element8according toFIG. 3can be integrated in preexisting tensioner blocks1designed in accordance with the prior art.

A further embodiment according to the invention of a tensioner block1is depicted inFIG. 4. In the transition area7, the tensioner block1forms a guide element8that is directed by a deflection area10thereof toward the feed section6. The guide element8delimits the feed section7in the direction of the cable guide2that is formed on the tensioner block1. The guide element8is designed in such a way in deflection area10thereof that at least a part of the gas that arrives from the feed section6is deflected to the right (according toFIG. 4). By deflecting the gas, the flow distance after which the gas meets the pull cable4is increased, seen inFIG. 4. Along this flow distance, the gas can continue to cool down, thereby reducing the weakening of the pull cable4.

Although tensioner block1forms a cable deflection in the illustrated embodiment, certain implementations can have pull cable4extending in a linear manner from pressure chamber3.