Seat belt tensioner for motor vehicle seat belt systems

Abstract

A seatbelt tensioner (27) for a seatbelt system in a motor vehicle includes at least one electric actuator (12). The seatbelt tensioner (27) is provided with a distributed autonomous energy storage device (20) configured to store sufficient electrical energy for operation of the actuator (12).

Description

[0001] The present invention relates to a seat belt tensioner for a seat belt system in a motor vehicle, comprising at least one electric actuator.

[0002] Today, seatbelt systems are no longer purely mechanical products. In addition to mechanical components, seatbelt systems may include pyrotechnic, electronic, and / or electromechanical components. Current reversible seatbelt tensioners can reduce seatbelt slack independently of the mounting point (in the tensioner or retractor, seatbelt buckle, or end attachment) under critical driving conditions, thereby restraining the occupant earlier. Such reversible seatbelt tensioners for seatbelt systems are well known in the prior art, for example, see DE 44 11 184 C2 and DE 100 29 061A1. One function of a reversible seatbelt tensioner is to pull the existing seatbelt slack from the seatbelt system in situations where an accident may subsequently occur (also known as the pre-collision phase or pre-accident phase), thereby allowing the occupant to adapt to vehicle deceleration as early as possible in subsequent potential accident conditions. This distributes the occupant load over the longest possible forward displacement path and reduces the maximum occupant load. In addition, reversible seat belt tensioners can also be used as warning systems to alert occupants to dangerous situations.

[0003] If no accident occurs after the pre-collision phase, the seatbelt tensioner is reactivated, and the seatbelt tension is reduced again. For this reason, reversible operation of the seatbelt tensioner is important. A reversible seatbelt tensioner can, for example, have an electric actuator, which is particularly easy to control without delay.

[0004] Generally, reversible seatbelt tensioners effectively prevent forward displacement from their designed position. The reaction time is in the range of milliseconds. Due to the short reaction time and the mechanical work required, a certain amount of electrical energy is needed.

[0005] Generally, there are a number of issues with seatbelt tensioners that include one or more electric actuators: i) How is the required electrical energy directed to the actuators in a short time? In this regard, the following factors also need to be considered: a smaller wire cross-section is desired in motor vehicles to reduce weight; the distance between the vehicle battery or generator and the actuator also needs to be considered; and the existence of separable electrical connection points when the seatbelt tensioner is installed in the vehicle seat. ii) How is power supply ensured in accident situations where there is a risk that the generator and / or vehicle battery may be damaged shortly after a collision (e.g., due to a short circuit), and / or disconnected by a safety switch for safety reasons, and / or disconnected incoming lines or plug-in connectors? iii) How is the required energy provided when the on-board electrical grid voltage is at a low limit or when many electrical devices simultaneously access the on-board electrical grid? In this regard, the following factors also need to be considered: to reduce weight, smaller generators are desired in motor vehicles; vehicle batteries may weaken in winter or due to aging, or their capacity may drop to a reserve state; shortly before the accident situation is determined (time point t0), current-consuming electrical equipment such as ESC (Electronic Stability Control), reversible seat belt tensioners, seat adjustment devices, and window regulators respond simultaneously, which puts a special load on the vehicle battery.

[0006] The object of this invention is to ensure reliable operability of the electric actuator under any possible circumstances.

[0007] The solution of the present invention to achieve the above-mentioned objective is a feature of the independent claim. According to the present invention, a distributed autonomous energy storage device is allocated to the seatbelt tensioner, which is configured to store sufficient electrical energy for the operation of the actuator. "Distributed" means that the energy storage device is provided separately from the vehicle battery and is located at or within the seatbelt tensioner. "Autonomous" means that the energy storage device operates independently and provides electrical energy regardless of the state of the vehicle battery or the state of the power supply line located between the vehicle battery and the seatbelt tensioner.

[0008] The solution of the present invention is a distributed, autonomous, and preferably diagnostic energy storage device, preferably arranged on the actuator. Here, the energy storage device can be a battery, accumulator, or capacitor capable of providing the required energy for various load conditions. The energy storage device preferably includes at least one supercapacitor, ultra-high-capacity capacitor, double-layer capacitor, or electrochemical capacitor to store the required energy within a small structural space. Preferably, at least one high-voltage capacitor with a rated voltage of at least 100V, preferably at least 200V, and more preferably at least 300V is used, as high-voltage capacitors generally require less structural space. Enclosing the energy storage device in a metal casing facilitates its implementation as a high-voltage capacitor, or more generally, facilitates electromagnetic shielding (Faraday cage) between the energy storage device's interior and its surrounding environment. However, for simple electrical insulation, a plastic casing can also be used for the energy storage device.

[0009] The application scenario, the required energy, and the internal voltage determine the volume of the energy storage device needed. For example, a large amount of energy is required to tension a seatbelt system, similar to a pyrotechnic tensioning mechanism. Accordingly, the energy storage device is preferably configured to store at least 100J, more preferably at least 150J, even more preferably at least 200J, at least 1000J, at least 1500J, or at least 2000J of energy. The installation location and the actuator used determine the structure and installation position of the energy storage device.

[0010] In a preferred embodiment, the at least one electric actuator comprises an electric motor advantageously configured to reversibly pretension and / or power-tension the seatbelt. In some embodiments, the energy storage device may be used to power an electromechanical force limiter. Preferably, the energy storage device is configured to store sufficient electrical energy to perform one or more of the following functions: reversible seatbelt pretensioning in pre-accident conditions; power-tensioning in the event of an unavoidable vehicle collision; and electromechanical force limiting. These functions are briefly described below.

[0011] In situations where a critical driving condition or impending accident is detected, but it is unclear whether a collision will occur, reversible seatbelt pretensioning is applied. In this situation, as a precaution, the seatbelt slack is retracted to better secure the occupant to the vehicle and prevent movement from their designed position. This facilitates subsequent power tensioning, as it can begin from the pre-tensioned level. If a collision is found to be avoidable, the seatbelt pretensioning is de-emerged, and the seatbelt can be freely extended again.

[0012] The seatbelt tensioner of the present invention can be advantageously applied to a variety of applications. A preferred application relates to a seatbelt retractor (tensioner). In some embodiments, the seatbelt retractor is constructed and configured to be arranged in a vehicle seat, particularly in the backrest of a vehicle seat. In this case, depending on the available space, it may be advantageous to arrange the belt retractor, force limiter, transmission, and electric motor coaxially within the seatbelt retractor, thereby forming a continuous longitudinal axis A.

[0013] Other possible applications of the seat belt tensioner of the present invention are as follows: arranged in a seat belt buckle as a so-called buckle tensioner, or arranged on an end accessory as a so-called end accessory tensioner.

[0014] Preferably, the energy storage device is used only to power the electrical components and actuators of the seatbelt tensioner, seatbelt system, or occupant restraint system including airbags, and not to power the electrical components and actuators of other vehicle systems. The advantage of this is that the energy is not consumed by other vehicle systems, and all the energy stored in the energy storage device is used by the seatbelt tensioner / seatbelt system / occupant restraint system.

[0015] Furthermore, by activating the electromechanical force limiter in regenerative mode, the energy storage device can be recharged. Therefore, when the seatbelt is pulled out under force limitation, the energy storage device is at least partially charged with energy. This energy can then be used, for example, to trigger an emergency call or warning signal.

[0016] The present invention will now be explained with reference to the accompanying drawings, based on preferred embodiments. In the accompanying drawings...

[0017] Figure 1 A seatbelt retractor for a vehicle seat is shown, comprising the seatbelt tensioner of the present invention employing a first embodiment;

[0018] Figure 2 A seatbelt retractor for a vehicle seat is shown, comprising the seatbelt tensioner of the present invention employing a second embodiment;

[0019] Figure 3 A seatbelt retractor for the B-pillar is shown, comprising a seatbelt tensioner of the present invention employing a third embodiment; and

[0020] Figure 4 A seatbelt retractor for B-pillar is shown, comprising the seatbelt tensioner of the present invention employing a fourth embodiment.

[0021] according to Figure 1 and Figure 2 The implementation relates to a seat belt retractor 10 for installation on or in a vehicle seat, particularly in a support beam, such as a crossbeam, in the backrest of the vehicle seat.

[0022] The seatbelt retractor 10 includes a housing 13 fixed to the vehicle. The housing contains load-bearing elements 18 and 19 fixed to the vehicle, such as a crossbeam 18, and fixing points 30 for securing the seatbelt retractor 10 to the vehicle structure. The seatbelt retractor 10 includes a reel 11 rotatably supported in the housing 13 or the U-shaped load-bearing element 19, on which an occupant seatbelt (not shown) can be wound. The reel 11 is anti-rotatably connected to a coaxial seatbelt shaft 14.

[0023] The seatbelt retractor 10 also includes a seatbelt tensioner 27, which comprises an electric motor 12 for rotating the seatbelt shaft 14 and consequently the reel shaft 11. The motor shaft 15 of the electric motor 12 is connected to a transmission 16 that transmits the rotational motion of the motor shaft 15 to the seatbelt shaft 14. For functional purposes, a force limiter 17 is provided between the transmission 16 and the reel shaft 11 to limit the force exerted by the seatbelt on the occupant during a vehicle collision. The force limiter 17 may, for example, comprise a torsion bar or be based on another mechanism of action.

[0024] The tape reel 11, force limiter 17, transmission device 16, and electric motor 12 are preferably arranged coaxially with each other (see reference). Figure 1 and Figure 2 Therefore, in general, the slender seatbelt retractor 10 extends along a coherent longitudinal axis A, which extends centrally through the seatbelt shaft 11 and the motor shaft 15. This arrangement is particularly suitable for mounting on a support beam fixed to a vehicle seat, such as a crossbeam in the backrest of a vehicle seat.

[0025] The electric motor 12 is configured to perform one or more of the following functions: reversible seatbelt pretensioning in pre-accident conditions; power tensioning in the event of an unavoidable vehicle collision; and electromechanical force limiting. These functions have been described above. Stored energy can also be selectively supplied to these functions, for example, depending on the situation, for power tensioning or force limiting. To implement these functions, the seatbelt retractor 10 preferably has a digital electronic control unit 19, which includes, for example, a microprocessor or microcontroller and is connected to the vehicle bus via signal line 21. Diagnostic signals containing data about the charging status and / or wear status of the energy storage device 20 can also be sent to the vehicle's electronic control unit via signal line 21. This advantageously makes the energy storage device 20 diagnostic, and appropriate measures can be taken, for example, in the event of wear in the energy storage device 20. The diagnostic data of the energy storage device can be transmitted to the control unit 19 via line 24, which facilitates charging control.

[0026] The seatbelt retractor 10 corresponds to an energy storage unit 20, which is designed to store sufficient energy to perform all the predetermined functions of the electric motor 12 (reversible seatbelt pretensioning, power tensioning, etc.) without external energy input, particularly without energy input through the vehicle battery. For example, upon receiving a pre-accident trigger signal via bus line 21, the control unit 19 controls the electric motor 12 to perform reversible seatbelt pretensioning, wherein the electrical energy required for this is obtained via power supply line 24, which connects the electric motor 12 directly or indirectly to the energy storage unit 20 through the control unit 19. This also applies, for example, to the case where an accident trigger signal is received in the control unit 19 via bus line 21. Therefore, the function of the seatbelt tensioner 10 is always ensured, whether in a pre-accident condition or an accident condition, even if the power supply line 22 is disconnected from the vehicle battery 23 or if the vehicle battery 23 is overloaded or fails for other reasons.

[0027] Preferably, the energy storage device 20, such as a supercapacitor, is designed and configured to store at least 100J, preferably at least 150J, more preferably at least 200J, and even more preferably 1000J, 1500J, or 2000J of energy. The energy storage device 20 is preferably part of the seatbelt retractor 10 and / or disposed within the housing 13. The energy storage device 20 may also be disposed outside the housing 13 and / or as a component independent of the seatbelt retractor 10.

[0028] Preferably, the energy storage device 20 can be enclosed by a metal housing 26. This allows the use of high-voltage capacitors with a voltage of 100V or higher, thereby advantageously further reducing the size of the energy storage device 20. Another advantage of the metal housing 26 is the electrical shielding (Faraday cage) between the interior of the energy storage device 20 and its surrounding environment. Preferably, the metal housing 26 can be grounded. An embodiment comprising a housing 26 made of plastic or a combination of a metal housing and a plastic housing can be adopted, thus easily achieving electrical insulation.

[0029] Control device 19 advantageously includes an electronic charging controller connected to vehicle battery 22 via power supply line 25. The charging controller charges energy storage device 20 when its charge is low or falls below a certain threshold. Furthermore, a transformer may be provided to convert the vehicle voltage into a charging voltage for energy storage device 20. This allows for charging cycles with a small current during normal vehicle operation. Smart charging can also be employed, where charging operation is terminated in critical situations and subsequently resumed during normal operation after the critical situation has ended. Energy storage device 20 can also be charged by utilizing the activation of an electromechanical force limiter, provided the energy storage device is coupled to it. This charging occurs during occupant restraint in an accident, or during occupant forward movement under force limitation in an accident, and can subsequently be used, for example, to send an emergency call or warning signal after the accident.

[0030] According to Figure 1 In this embodiment, the energy storage unit 20 is elongated, for example cylindrical, and advantageously arranged parallel to the longitudinal axis A of the seatbelt retractor 10, for example, below the shaft axes 14, 15. To allow for the use of a relatively thin energy storage unit 20 (i.e., with a relatively small diameter) depending on the available structural space, the energy storage unit 20 preferably includes several smaller, for example cylindrical, storage units 23, such as… Figure 1 The energy storage unit 20 is arranged in series along its longitudinal axis. The energy storage unit 20 can advantageously be held on one or more crossbeams 18. The tensioner / retractor 10 and the energy storage unit 20 can advantageously be arranged within the upper crossbeam of the vehicle seat, thereby providing sufficient space for occupant to sink in, for example, in the event of a rear-end collision.

[0031] According to Figure 2 In one embodiment, the energy storage unit 20 is, for example, cylindrical and advantageously arranged radially, laterally, obliquely, or torsionally relative to the longitudinal axis A of the seatbelt retractor 10. In this embodiment, the energy storage unit 20 is, for example, a separate component and may be arranged, for example, in or on a side beam of the vehicle seat back.

[0032] according to Figure 3 and Figure 4 The implementation relates to its use in the tensioner 10, particularly for its installation in the B-pillar of a vehicle. Here, the energy storage device 20 is parallel to the axis A of the shaft. Figure 3 The actuator (electric motor 12) is positioned either above or below the tape reel 11, depending on its location, as the structural space in the x and y dimensions within the B-pillar is very limited. Figure 4 As shown, the design of the B-pillar may also necessitate the installation of a separate energy storage unit 20. Alternatively, a method such as... Figure 4 The vertical or radial layout relative to the axis A of the shaft is shown.

[0033] These figures depict an energy storage device 20 for operating the electric motor 12 in the seatbelt retractor 10. This can be applied accordingly to the buckle tensioner or end-accessory tensioner of the seatbelt system.

Claims

1. A seatbelt tensioner (27) for a seatbelt system in a motor vehicle, the seatbelt tensioner comprising: - At least one electric actuator (12), operatively connected to the seat belt of the seat belt system, said at least one electric actuator (12) being part of an electromechanical force limiter. Its features are, - A distributed autonomous energy storage device (20) is allocated to the seat belt tensioner (27), the energy storage device (20) being configured to store sufficient electrical energy for the operation of the electric actuator (12); The energy storage device (20) can be recharged by activation of the electromechanical force limiter. After the seat belt is pulled out under electromechanical force limiter, the energy storage device (20) is at least partially charged with energy, which is then used to trigger an emergency call or warning signal.

2. The seat belt tensioner (27) according to claim 1, characterized in that, The energy storage device (20) includes batteries, storage batteries and / or capacitors, particularly supercapacitors.

3. The seat belt tensioner (27) according to claim 1, characterized in that, The energy storage device (20) includes at least one high-voltage capacitor with a rated voltage of at least 100 V.

4. The seat belt tensioner (27) according to claim 1, characterized in that, The energy storage device (20) is configured to store at least 100 J of energy.

5. The seat belt tensioner (27) according to claim 1, characterized in that, The at least one electric actuator (12) includes an electric motor.

6. The seat belt tensioner (27) according to claim 5, characterized in that, The electric motor is configured to reversibly pretension and / or power tension the seat belt.

7. The seat belt tensioner (27) according to claim 1, characterized in that, The energy storage device (20) is configured to store electrical energy sufficient to perform one or more of the following functions: -Pretension the reversible seatbelt under pre-accident conditions; - Power tensioning is applied in cases where a vehicle collision is unavoidable; - Electromechanical force limitation.

8. The seat belt tensioner (27) according to claim 1, characterized in that, The energy storage device (20) has a metal casing (26).

9. A seatbelt retractor (10), characterized in that, The seatbelt retractor includes - A reel (11) rotatably supported in a housing that can be fixed to a vehicle, on which the seat belt can be wound, and - The seat belt tensioner (27) according to any one of claims 1 to 8.

10. The seatbelt retractor (10) according to claim 9, characterized in that, The seatbelt retractor (10) is constructed and configured to be arranged in the vehicle seat.

11. The seatbelt retractor (10) according to claim 9 or 10, characterized in that, The tape reel (11), force limiter (17), transmission device (16) and electric motor are arranged coaxially to form a continuous longitudinal axis A.

12. A seatbelt buckle for a seatbelt system in a motor vehicle, characterized in that, The seat belt buckle has a seat belt tensioner (27) according to any one of claims 1 to 8.

13. A seatbelt end accessory for a seatbelt system in a motor vehicle, characterized in that, The end accessory has a seat belt tensioner (27) according to any one of claims 1 to 8.

Images