Tension device for safety belt components

Abstract

To provide a tensioning device that can more reliably achieve a uniform tensioning process. [Solution] The system comprises a gas generator (1) that generates compressed gas, a piston (2) that can be driven by the compressed gas, a tension cable connected to the piston (2) and connectable to a safety belt component that is subjected to tensioning motion, a tensioner tube (5) for housing and guiding the piston (2), a gas generator housing (6) disposed in the tensioner tube (5) and housing the gas generator (1), and a seal (7) on the side facing the piston (2) that seals the gas generator housing (6) against the inner surface of the tensioner tube (5), wherein the seal (7) has a first seal lip that extends along the longitudinal direction of the tensioner tube (5), and at least when the gas generator (1) is started, it abuts flat against the inner surface of the tensioner tube (5) and is pressed against the inner surface of the tensioner tube (5) by the compressed gas.

Description

Technical Field

[0001] The present invention relates to a tensioning device for a seat belt component. In particular, the present invention relates to a tensioning device comprising a gas generator, a piston, a tension cable, a tensioner tube, a gas generator housing, and a special seal.

[0002] In the field of vehicle safety, it is common to use various devices and mechanisms to enhance the safety of vehicle occupants during an accident. One of these devices is the seat belt, which is used to securely hold the occupant in the seat and thereby minimize the risk of injury during a collision. To further enhance the effectiveness of the seat belt, a tensioning device is often used to tighten the belt during an accident to more securely fix the occupant. Known systems typically include a gas generator that generates compressed gas to drive a piston during an accident. This piston is connected to a tension cable, which is also connected to a seat belt component to cause a tensioning movement.

[0003] According to known technology, these tensioning devices often include a tensioner tube that houses and guides the piston. The gas generator is housed in a gas generator housing that is inside the tensioner tube. The seal results in the compressed gas driving the piston without leakage. Despite significant progress in the field of tensioning devices, there are still problems, particularly with respect to sealing and the efficiency of force transmission from the gas generator to the piston. Known seal solutions may not function under extreme conditions or may not seal optimally, which can compromise the performance of the tensioning device.

[0004] Another problem is that the seals in existing systems often lack sufficient flexibility to accommodate various pressure conditions and mechanical loads. This can lead to uneven contact pressure. Furthermore, inadequate seals can cause compressed gases to leak before the piston can be fully driven, which reduces the tensioning effect of the safety belt.

[0005] According to prior art, an O-ring is typically used as a seal between the gas generator housing and the inner surface of the tensioner tube. A tensioning device having the features of the premise of claim 1 is known from German Patent No. 102022122768.

[0006] Therefore, an improved seal is needed that ensures a more reliable seal while simultaneously possessing sufficient flexibility to accommodate various operating conditions.

[0007] Therefore, the object of the present invention is to provide a tensioning device that overcomes one or more of the shortcomings of known tensioning devices, and in particular, to provide a tensioning device that can more reliably achieve a uniform tensioning process.

[0008] The above problems are solved by a tensioning device having the features of the independent claim. Advantageous developments are described in the dependent claims and in the above and below descriptions, and the individual features of the advantageous developments can be combined with each other in a technically meaningful way.

[0009] This problem is solved, in particular, by a tensioning device for a safety belt component equipped with a gas generator for producing compressed gas. A piston is driven by the compressed gas and connected to a tension cable, which can also be connected to the safety belt component to perform tensioning motion. A tensioner tube is used to house and guide the piston, and a gas generator housing houses the gas generator and is located within the tensioner tube. A seal is located on the piston-facing side of the gas generator housing and seals the gas generator housing against the inner surface of the tensioner tube. Thus, the seal is intended to seal the space within the tensioner tube into which the compressed gas is introduced and to prevent the compressed gas from flowing out along the intermediate space between the outer surface of the gas generator housing and the inner surface of the tensioner tube.

[0010] The seal has a first seal lip that extends along the longitudinal direction of the tensioner tube. This seal lip is in contact flat with the inner surface of the tensioner tube, at least when the gas generator is started, and is pressed against the inner surface of the tensioner tube by the compressed gas. The advantage of this design is a more reliable and uniform tensioning process.

[0011] In other words, the present invention, in its conception, intends for the seal to have a flat portion that is pressed against the inner surface of the tensioner tube at least during startup, thereby providing a flat contact area between the seal and the inner surface of the tensioner tube, in which the seal abuts the inner surface of the tensioner tube with uniform pressure. The flat portion of the seal is called the seal lip. Thus, a larger sealing surface is provided compared to an O-ring with a circular cross-section, and furthermore, this abuts the inner surface of the tensioner tube more uniformly. Thus, a more uniform tensioning process is ensured, as compressed gas does not leak much or at all along the gas generator housing. The seal lip can extend entirely in the circumferential direction. However, it is also possible to intend for the seal lip to be formed in only one or more portions in the circumferential direction. Thus, the seal lip is formed in particular in a region of the tensioner tube that is not curved in the tensioner tube itself.

[0012] According to one embodiment, the tensioning device includes a seal having a base that abuts against the axial end face of the gas generator housing. The axial end face of the gas generator housing is the housing surface facing the piston, particularly oriented in the direction of the longitudinal axis of the tensioner tube. The end face of the gas generator housing may have a plurality of parts that are stepped relative to each other. The end face or each part of the end face is preferably formed flat. The base of the seal is the part of the seal that abuts directly against the axial end face or a part of the axial end face of the gas generator housing. This area of ​​the base is preferably formed flat to enable optimal sealing. This flat contact improves the seal between the gas generator housing and the tensioner tube, thereby increasing the efficiency of the tensioning device. Forming both the axial end face and the base flat prevents uncontrolled leakage of compressed gas generated by the gas generator, thereby contributing to the utilization of all the energy of the compressed gas for piston movement. The flat contact of the base at the axial end face ensures that the seal is reliably tight even under high pressure and high-speed piston movement, resulting in effective utilization of the compressed gas energy.

[0013] According to one embodiment, the tensioning device has a special arrangement / design of seals in which the base of the seal contacts the end face of the gas generator housing at a distance from the outer edge of the end face of the gas generator housing. Thus, the radial (outer) edge of the base is spaced apart from the radial (outer) edge of the gas generator housing. Therefore, the base does not contact the radial edge of the gas generator housing at the end face. This seal arrangement has several advantages. By spaced the base apart from the outer edge of the end face of the gas generator housing, the seal is prevented from being pushed into the minimum gap between the gas generator housing and the inner surface of the tensioner tube. This is advantageous for ensuring a secure seal and efficient transfer of compressed gas. As a result, the seal remains in its intended position, and the compressed gas can optimally drive the piston without leakage or pressure loss.

[0014] According to one embodiment, the tensioning device has a seal whose outer circumference is formed conically at the transition from the base to the first seal lip. Thus, the diameter of the seal increases from the base facing the end face of the gas generator housing to the first seal lip. This conical design of the seal in the transition region provides an effective seal and prevents the seal from being pushed into the minimum gap between the gas generator housing and the inner surface of the tensioner tube. This special shape makes the seal more stable and allows for optimal absorption and distribution of the pressure of the generated gas. The conical shape allows the seal to contact the inner wall of the tensioner tube uniformly when pressure is applied, thereby preventing it from being pushed into the gap, which enhances the sealing effect and improves the reliability of the tensioning device. By avoiding the seal entering the gap, the risk of malfunction is also minimized, which leads to higher operational reliability of the entire device.

[0015] In one embodiment of the tensioning device, the first seal lip extends axially beyond the gas generator housing. This special extension of the seal lip allows for improved sealing and interaction between the components of the tensioning device. The seal lip extending along the longitudinal direction of the tensioner tube results in the gas generator housing being effectively sealed against the inner surface of the tensioner tube. The axial extension of the seal lip beyond the gas generator housing maintains the sealing effect even when the piston moves and compressed gas is generated. This leads to improved efficiency of the tensioning device, as the compressed gas is optimally utilized to drive the piston and thereby cause the safety belt components to tension. The extended seal lip ensures that the compressed gas does not leak, thereby allowing the full energy of the gas generator to be utilized. The first seal lip extends at least 5 mm, preferably at least 10 mm, beyond the gas generator housing along the inner surface of the tensioner tube.

[0016] According to one embodiment, the tensioning device has a second seal lip extending along the longitudinal direction of the tensioner tube, the second seal lip making flat contact with the radially outward-facing surface of the gas generator housing at least when the gas generator is started, and being pressed against the radially outward-facing surface of the gas generator housing by the compressed gas. This radially outward-facing surface of the gas generator housing is located, in particular, between two portions of the axial end face of the gas generator housing, thereby forming a stepped end face of the gas generator housing. This arrangement / design allows the second seal lip to make flat contact with the outward-facing surface of the gas generator housing, which further enhances the airtightness between the gas generator housing and the tensioner tube. Thus, the second seal lip acts as an additional barrier to prevent the leakage of compressed gas and ensures that the compressed gas is efficiently utilized to drive the piston and initiate the tensioning motion of the safety belt component. Since no undesirable leaks occur, this leads to further improvements in the performance of the tensioning device. The stepped design of the end face of the gas generator housing assists in effective sealing by providing a suitable support surface for the second seal lip. Thus, this additional seal lip contributes to the overall reliability and efficiency of the tensioning device by ensuring a double seal in combination with the first seal lip and minimizing the risk of pressure loss. The second seal lip ensures that when the gas generator is operating, the seal is pressed against the axially outward-facing surface by the compressed gas, which results in a secure and tight connection.

[0017] In particular, the first seal lip and the second seal lip are integrally formed with the base. The first seal lip extends from the base along the longitudinal extension of the tensioner tube and abuts against the inner surface of the tensioner tube, while the second seal lip extends from the base along the longitudinal extension of the tensioner tube and abuts against the radially outward-facing surface of the gas generator housing. That is, the base connects the first seal lip and the second seal lip. In this case, the seal is preferably formed in a U-shape on the side facing the pressure chamber, and the U-shaped legs forming the first seal lip can be longer than the U-shaped legs forming the second seal lip, in which case the side is rather J-shaped.

[0018] According to one embodiment, the tensioning device includes a first seal lip that extends at least 1.5 times, preferably 2 times, the length of the second seal lip in the longitudinal direction of the tensioner tube. This special design of the first seal lip allows for improved sealing and enhances the efficiency of the tensioning device. The longer first seal lip results in a larger contact surface between the seal lip and the inner surface of the tensioner tube when the gas generator is started. This allows the compressed gas to be pressed more effectively against the inner surface of the tensioner tube, resulting in a better seal. Furthermore, the extended first seal lip improves the seal's fit to irregularities or tolerances on the inner surface of the tensioner tube, which further enhances the overall reliability of the tensioning device.

[0019] According to one embodiment, the tensioning device has a first seal lip that extends at different distances in the longitudinal direction at several circumferential locations. The different longitudinal extensions of the seal lip improve the fit to the inner surface of the tensioner tube, thereby improving the efficiency of the seal. In this way, the seal conforms to the cross-sectional shape of the tensioner tube. This leads to improved sealing against compressed gas, thereby preventing gas leakage at undesirable locations. Another advantage of this embodiment is the high flexibility of the seal, which can better conform to the shape and, if any, irregularities present on the inner surface of the tensioner tube. The special design of the seal lip also facilitates the manufacture and assembly of the tensioning device, as it ensures a more precise fit.

[0020] According to one embodiment of a tensioning device for a safety belt component, the first seal lip has a special configuration that extends further next to the tension cable than at points further away. This special design of the seal lip optimizes sealing near the tension cable.

[0021] According to one embodiment, the seal has reinforcing ribs. These reinforcing ribs are structural elements incorporated into / on the first seal lip to enhance its mechanical strength and stability. The reinforcing ribs further stabilize the seal lip, thereby improving its ability to withstand the pressure of the generated gas and ensure an effective seal. The reinforcing ribs result in the seal lip maintaining its shape and not deforming even under high-pressure conditions, thereby increasing the reliability of the seal. The reinforcing ribs can be made of the same material as the seal lip, or of a different, particularly resistant material that further improves the structural integrity of the seal lip. By incorporating these reinforcing ribs into the seal lip, the entire tensioning device becomes more robust and reliable.

[0022] According to one embodiment, the tensioning device comprises two or an even number of reinforcing ribs arranged in pairs facing each other in the seal. By arranging the reinforcing ribs on opposing sides of the seal, an even distribution of forces acting on the seal is achieved. This prevents deformation or displacement of the seal that could lead to loss of sealing. The reinforcing ribs further stabilize the seal lip and improve its functionality. The reinforcing ribs can be an integrated component of the seal and can be manufactured in a single manufacturing process, thereby reducing production costs and increasing manufacturing efficiency.

[0023] According to one embodiment, the tensioning device comprises two reinforcing ribs that are larger in mass than the remaining reinforcing ribs and are positioned opposite each other. The additional mass of the two special reinforcing ribs improves the distribution of forces acting on the seal, which leads to a more effective seal. The special arrangement and mass distribution of the reinforcing ribs are designed to provide an optimal balance between flexibility and strength, thereby ensuring that the seal functions even under extreme conditions.

[0024] In one embodiment of the tensioning device, reinforcing ribs extend to the second seal lip, thereby providing additional structural support and stability to the seal. The reinforcing ribs result in the seal maintaining its shape and position even under high pressure and high-speed piston movement. The reinforcing ribs also contribute to facilitating the assembly of the tensioning device by enabling precise positioning and alignment of the seal within the tensioner tube. This reduces the possibility of assembly errors and improves the overall quality of the tensioning device.

[0025] According to an embodiment of the present invention, the seal is integrally formed. This integrally formed seal design has several advantages. First, the manufacturing of the seal is simplified because there is no need for additional assembly processes to connect multiple components to each other. As a result, potential vulnerable points that could occur due to the presence of connection points are removed, reducing production costs and improving seal reliability. Furthermore, the integral seal improves the sealing effect because there are no joints or transition parts where compressed gas could leak.

Brief Description of the Drawings

[0026] Hereinafter, the present invention and the technical environment will be exemplarily described based on schematic diagrams.

[0027] [Figure 1] It is a diagram showing an embodiment of a tension device for a safety belt component. [Figure 2] It is a cross-sectional view of an embodiment of the tension device. [Figure 3] It is a detailed cross-sectional view of the seal of the tension device and the gas generator housing. [Figure 4] It is a diagram showing the seal of the tension device. [Figure 5] It is a perspective view of the seal.

[0028] Figure 1 shows a tension device for a safety belt component. This device includes a gas generator 1 for generating compressed gas. The gas generator 1 is housed within a gas generator housing 6, and the gas generator housing 6 is also disposed within a tensioner tube 5.

[0029] The tensioner tube 5 also has a piston 2 driven by compressed gas. A tension cable 3 is connected to the piston 2, and the piston is connected to a safety belt component 4 that is caused to move with tension applied.

[0030] The seal 7, also shown in Figure 5, is located on the side of the gas generator housing 6 facing the piston 2 and seals it against the inner surface of the tensioner tube 5. The seal 7 has a first seal lip 7.1 that extends along the longitudinal direction of the tensioner tube 5 and is in contact flat with the inner surface of the tensioner tube 5 at least when the gas generator 1 is started and is pressed against the inner surface of the tensioner tube by the compressed gas.

[0031] Furthermore, the seal 7, which can be seen in more detail in Figures 3 to 5, has a base portion 7.3 that abuts against the axial end face of the gas generator housing 6. The base portion 7.3 is spaced apart from the outer edge of the end face of the gas generator housing 6. At the transition from the base portion 7.3 to the first seal lip 7.1, the outer circumference of the seal 7 is formed in a conical shape.

[0032] The seal 7 also has a second seal lip 7.2 that extends along the longitudinal direction of the tensioner tube 5, and at least when the gas generator 1 is started, it contacts flat against a radially outward-facing surface 6.3 of the gas generator housing 6 and is pressed against this surface 6.3 by the compressed gas.

[0033] The first seal lip 7.1 has a length of at least 1.5 times that of the second seal lip 7.2 in the longitudinal direction of the tensioner pipe 5. The first seal lip 7.1 extends at different distances in the longitudinal direction at several points in the circumferential direction, extending further next to the tension cable 3 than at points further away.

[0034] The first seal lip 7.1 has reinforcing ribs 7.4, with two reinforcing ribs 7.4 positioned opposite each other in the seal 7. In the figure, the reinforcing ribs 7.4 positioned opposite each other above and below have a greater mass than the remaining reinforcing ribs 7.4.

[0035] Seal 7 is designed as a single unit for easy assembly and to ensure a reliable seal.

[0036] Figures 2 and 3 show detailed diagrams of the tensioning device of the safety belt component.

[0037] Figure 2 shows a cross-sectional view of a tensioning device, including the tensioner tube 5, gas generator 1, gas generator housing 6, and seal 7. The tensioner tube 5 is used to house and guide the piston 2, which is driven by the compressed gas of the gas generator 1. The gas generator housing 6 is located inside the tensioner tube 5 and houses the gas generator 1. The seal 7 is located on the side of the gas generator housing 6 facing the piston 2 and seals it against the inner surface of the tensioner tube 5.

[0038] Figure 3 shows an enlarged view of the lower region of the tensioning device, where the seal 7 is shown in more detail. The first seal lip 7.1 can be seen, which extends along the longitudinal direction of the tensioner tube 5 and contacts the inner surface of the tensioner tube 5 flat when the gas generator 1 is started. This first seal lip 7.1 is pressed against the inner surface of the tensioner tube 5 by the compressed gas to ensure an effective seal.

[0039] Furthermore, Figure 3 shows that the seal 7 has a base 7.3 that abuts against the axial end face 6.1 of the gas generator housing 6. The base 7.3 is positioned spaced apart from the outer edge 6.2 of the end face 6.1 of the gas generator housing 6, which allows for precise positioning of the seal 7 and improves sealing.

[0040] Furthermore, in Figure 3, it can be seen that a second seal lip 7.2 similarly extends along the longitudinal direction of the tensioner tube 5. This second seal lip 7.2 comes into flat contact with the radially outward-facing surface 6.3 of the gas generator housing 6 when the gas generator 1 is started, and is pressed against this surface 6.3 by the compressed gas.

[0041] The first seal lip 7.1 extends axially beyond the gas generator housing 6 and has reinforcing ribs 7.4 that enhance the structural integrity of the seal 7.

[0042] Seal 7 is designed as a single unit, which allows for easy manufacturing and assembly.

[0043] Figure 4 shows a cross-section of the tensioning device, particularly the arrangement of the seal 7 within the tensioner tube 5. The gas generator housing 6 is positioned within the tensioner tube 5.

[0044] Figure 5 shows a perspective view of the seal 7. The seal 7 is designed as a single unit and comprises a first seal lip 7.1, a second seal lip 7.2, and a base 7.3. The outer circumference of the transition from the base 7.3 to the first seal lip 7.1 of the seal 7 is formed in a conical shape. Furthermore, the seal 7 has reinforcing ribs 7.4, which are used to enhance structural integrity. Two of these reinforcing ribs 7.4 are positioned opposite each other in the seal 7. The reinforcing ribs 7.4 extend to the second seal lip 7.2.

[0045] The special design of the seal lips 7.1, 7.2 and reinforcing ribs 7.4 contributes to the effective sealing and functionality of the tensioning device by ensuring that compressed gas is optimally utilized to quickly and reliably tighten the safety belt components in the event of an accident. [Explanation of Symbols]

[0046] 1. Gas generator 2 pistons 3. Tension Cable 4. Safety belt components 5. Tensioner tube 6. Gas generator housing 6.1 Axial end face 6.2 Outer edge 6.3 Surfaces facing radially outward 7 stickers 7.1 First Seal Lip 7.2 Second Seal Lip 7.3 Base 7.4 Reinforcement Ribs

Claims

1. A tensioning device for the safety belt component (4), - A gas generator (1) for producing compressed gas, - A piston (2) that can be driven by the compressed gas, - A tension cable (3) connected to the piston (2) and connectable to a safety belt component that applies tension, - A tensioner tube (5) for housing and guiding the piston (2), - A gas generator housing (6) that houses the gas generator (1), the gas generator housing (6) being positioned inside the tensioner tube (5), - A tensioning device comprising a seal (7) which, on the side facing the piston (2), seals the gas generator housing (6) against the inner surface of the tensioner tube (5), The seal (7) has a first seal lip (7.1) extending along the longitudinal direction of the tensioner tube (5), and at least when the gas generator (1) is started, it abuts flat against the inner surface of the tensioner tube (5) and is pressed against the inner surface of the tensioner tube (5) by the compressed gas. A tensioning device characterized by the following features.

2. The tension device according to claim 1, wherein the seal (7) has a base (7.3) that abuts against the axial end face (6.1) of the gas generator housing (6).

3. The tension device according to claim 2, wherein the base portion (7.3) is spaced apart from the outer edge (6.2) of the axial end face (6.1) of the gas generator housing (6) and abuts against the axial end face (6.1).

4. The tension device according to claim 3, wherein the seal (7) has a conical outer circumference at the transition portion from the base (7.3) to the first seal lip (7.1).

5. The tensioning device according to any one of claims 1 to 4, wherein the first seal lip (7.1) extends axially beyond the gas generator housing (6).

6. The tensioning device according to any one of claims 1 to 5, wherein the seal (7) has a second seal lip (7.2) extending along the longitudinal direction of the tensioner tube (5), and at least when the gas generator (1) is started, it abuts flat against the radially outward-facing surface (6.3) of the gas generator housing (6) and is pressed against the radially outward-facing surface (6.3) of the gas generator housing (6) by the compressed gas.

7. The tensioning device according to claim 6, wherein the first seal lip (7.1) has a length of at least 1.5 times, preferably at least 2 times, that of the second seal lip (7.2) in the longitudinal direction of the tensioner tube.

8. The tensioning device according to any one of claims 1 to 7, characterized in that the first seal lip (7.1) extends at different distances in the longitudinal direction at several locations in the circumferential direction.

9. The tensioning device according to claim 8, wherein the first seal lip (7.1) extends further next to the tension cable (3) than at a more distant point.

10. The tensioning device according to any one of claims 1 to 9, wherein the first seal lip (7.1) has a reinforcing rib (7.4).

11. The tensioning device according to claim 10, wherein the two reinforcing ribs (7.4) are arranged in the seal (7) opposite each other.

12. The tensioning device according to claim 10 or 11, wherein two reinforcing ribs (7.4) arranged opposite each other have a greater mass than the remaining reinforcing ribs (7.4).

13. The tensioning device according to any one of claims 10 to 12, wherein the reinforcing rib (7.4) extends to the second seal lip (7.2).

14. The tension device according to any one of claims 1 to 13, wherein the seal (7) is integrally formed.

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