Seatbelt retractor with an electrically operated blocking device

Description

[0001] The present invention relates to a belt retractor with an electrically actuated locking device having the features of the preamble of claim 1.

[0002] An electrically actuated locking device of this type is known, for example, from GB 2 398 824 A.

[0003] Such blocking devices serve to stop an externally toothed control disc, which is rotatably mounted on a belt shaft of the belt retractor, by engaging a blocking lever relative to the belt shaft and thereby forcing a blocking pawl to engage a steering movement in a vehicle-fixed toothing, which in turn blocks the belt shaft in the extension direction.

[0004] In conventional mechanical locking devices, an inertial mass is mounted on a contact surface. When a predetermined vehicle deceleration is exceeded, this mass is deflected, thereby deflecting the locking lever and forcing it to engage the teeth of the control disc. Such mechanical locking devices are also referred to as vehicle-sensitive sensor devices. One problem with these mechanical locking devices is that the inertial mass must always be aligned in a defined orientation on the contact surface relative to the vehicle's longitudinal and transverse axes, regardless of the installation geometry of the seatbelt retractor, to prevent the belt shaft from being unintentionally blocked.This means the seatbelt retractor must be designed specifically for each vehicle. The orientation of the contact surface and the mass resting on it must be individually designed to match the retractor's installation geometry within the vehicle. Furthermore, with seatbelt retractors integrated into the front seats, such as in convertibles, the problem arises that when the backrest angle is adjusted or the backrests are folded forward to allow access to the rear seats, the inertial mass can be unintentionally deflected on the contact surface. This can force the locking lever into an engagement with the outer teeth of the control disc. As a result, the retractor is blocked in the extension direction, and the backrest cannot be tilted further, preventing the occupant from fastening their seatbelt. To prevent this, additional locking mechanisms or...Compensating mechanisms must be provided, but these may only activate in specific cases to ensure the occupant's restraint in the event of an accident. These challenges make such a mechanical locking device mechanically very complex.

[0005] In an electrically actuated locking device, such as that known from GB 2 398 824 A, the movement of the locking lever is electrically controlled, thus eliminating the previously required inertial mass. The belt retractor can therefore be installed unchanged in various mounting positions within the vehicle and even in seat backrests. Furthermore, the locking of the belt shaft can be controlled by an electrical signal from a control unit. This signal can be generated by a control unit that can also generate the signal based on other sensor devices or control systems. For example, it is conceivable to automatically lock the belt shaft when a vehicle dynamics assistance system is activated, which is, for example, controlled based on a signal from an optical sensor device.This also allows the electrically actuated locking device to be controlled directly or indirectly, depending on the signal from the optical sensor. Furthermore, the electrically actuated locking device functions in any orientation and configuration, as it is not actuated by inertial forces and therefore does not need to be aligned in a specific direction relative to the vehicle's direction of travel. This allows it to be preferably installed in seats of at least partially autonomous vehicles, which the occupant can adjust within a significantly wider range of motion than is possible with seats in conventional, non-autonomous vehicles, thus improving communication with other occupants, allowing for a resting position, or generally enabling the use of the freedoms gained through autonomous driving.

[0006] An electrically actuated locking device 100 used by the applicant in its products, which corresponds to the embodiment of GB 2 398 824 A, is in the Figures 1 and 2 as a single item and in the Figure 3shown on a seatbelt retractor. The electrically actuated locking device 100 comprises as basic elements a housing 1 with an L-shaped base structure with a base plate 15 and a first raised leg 16, a locking lever 2 pivotally mounted on the first raised leg 16 of the housing 1, an electromagnet 3, and a first spring 4, which is held at one end to the housing 1 and connected at the other end to a lever arm 22 of the locking lever 2 projecting outwards from the first raised leg 16. The first spring 4 is designed as a tension spring such that it biases the locking lever 2 into a position in which it engages with a locking tip 25 in a toothing 26 of a control disc 21 and thereby holds the control disc 21 against the belt shaft 20. The control disc 21 with the toothing 26 is only in the Figure 3This can be seen in a seatbelt retractor. When the belt shaft 20 rotates in the extension direction, the locking pawl is automatically forced into an engagement movement with a vehicle-mounted toothed section, and the belt shaft 20 is subsequently blocked against further belt extension. The locking lever 2 comprises a contoured part 24 and a steel plate 5, with the steel plate 5 facing the electromagnet 3. When the electromagnet 3 is energized, the locking lever 2 is attracted by it and thus pulled out of the toothed section 26 of the control disc 21. This allows the belt shaft 20 to rotate freely in both the extension and retraction directions. The advantage of this solution is that the belt shaft 20 remains blocked in the extension direction even in the event of a power failure or a defect in the electromagnet 3, and the occupant is safely restrained in this case as well.

[0007] The electromagnet 3 comprises a base component 6 with a column-shaped central section 7 and two radial flanges 8, one of which projects radially outwards at each end of the central section 7. The electromagnet 3 is held by the base component 6 on the base plate 15 of the housing 1. The base component 6 has a tubular through-section 14 in the central section 7 and an annular space 9 radially outside the central section 7, the annular space 9 being bounded at the ends of the central section 7 by the radial flanges 8. Furthermore, the electromagnet 3 comprises a coil 10 with a plurality of turns, which is arranged in the annular space 9 and is electrically contacted with an external control device via lines 11 provided in the base component 6.Furthermore, the electromagnet 3 comprises a first iron core 12, which is arranged in the tubular passage section 14 of the basic component 6 and faces the steel plate 5 of the locking lever 2 with a free end.

[0008] When the coil 10 is energized, the locking lever 2 is attracted by closing a first magnetic circuit I, defined by the first raised leg 16 of the housing 1, the first iron core 12, and the sections of the locking lever 2 and the base plate 15 between the first iron core 12 and the first raised leg 16, as shown in the right-hand illustration of the Figure 2This can be seen. Furthermore, a damping element 13 in the form of a flexible tube, e.g., a short piece of hose, is provided, which is clamped at its ends between two projections of the radial flange 8 facing the locking lever 2. The damping element 13 is positioned such that the free end of the locking lever 2 does not rest against the damping element 13 in the deflected position (left illustration of the Figure 2 ) and only in the tightened position does it reach the attachment point at the central soft section of the damping element 13 between the clamping points (right illustration of the Figure 2 This dampens the pulling movement of the locking lever 2 in the final phase of the movement. This damping ensures a soft stop and prevents disruptive "rattling noises" during the pulling movement and any subsequent minor movements of the locking lever 2.

[0009] The object of the invention is to provide a belt retractor of the generic type with reduced noise generation and a simplified basic design.

[0010] To solve the problem, a belt retractor with the features of claim 1 is proposed. Further preferred embodiments of the invention can be found in the dependent claims, the figures, and the accompanying description.

[0011] According to the basic idea of ​​the invention, it is proposed that a projection be provided on the housing which is shaped in such a way that the first spring rests against it regardless of the position of the locking lever and is pre-tensioned transversely to the spring force exerted on the lever arm.

[0012] The proposed solution provides additional preload to the first spring, thus fixing it against uncontrolled movement. This reduces noise generation by preventing contact between the first spring and adjacent parts of the locking mechanism. The spring is preloaded independently of the locking lever's position, so that the first spring is tensioned by the projection both when the locking lever is deflected (i.e., when the belt shaft is blocked) and when the locking lever is engaged (i.e., when the belt shaft is released). The first spring rests against the projection in such a way that it is preloaded perpendicular to the spring force it exerts on the lever arm, ensuring that the lever arm's movement has no or only a minimal influence on the preload exerted by the projection on the first spring.

[0013] The decisive advantage of the proposed solution lies in the fact that the movement of the first spring, which triggers the movement of the locking lever, is directly restricted. This reduces noise generation as close as possible to its point of origin, where the first spring is clamped to the locking lever and the housing. The preload of the first spring not only increases its clamping force between the locking lever and the housing, but also reduces potential lateral movement of the first spring, thereby minimizing the likelihood of it striking adjacent components of the locking mechanism and the associated noise generation.

[0014] It is further proposed that the first spring be held at a second end in the area of ​​the base plate, and that the projection be arranged on the first leg of the housing, which extends upwards from the base plate. The first spring thus extends laterally along the locking device from the base plate to the lever arm of the locking lever, so that the first leg provides a structurally simple surface on which the projection can be positioned. Furthermore, the first spring offers an intermediate section, as long and freely accessible as possible, in the area between the mounting on the lever arm and in the area of ​​the base plate, against which the projection can rest and over which the first spring can be tensioned.

[0015] It is further proposed that the projection be integrally formed onto an attachment part held on the housing. This eliminates the need to modify the housing itself, provided it already has a sufficient mounting surface for attaching the attachment part. Furthermore, the attachment part can be individually shaped to form the projection and its mounting can be aligned such that the first spring, by virtue of its attachment to the locking device, automatically comes into contact with it and is pre-tensioned according to the invention.

[0016] The attachment part preferably has a retaining projection located in the area of ​​the base plate, and the first spring can be held at its second end by this retaining projection. The attachment part thus also serves to secure the second end of the spring, which offers the advantage that the projection and the retaining projection of the first spring for its second end are realized on one and the same part and are therefore arranged in a fixed spatial relationship to each other. Furthermore, the housing does not need to be designed to form either the projection or to secure the second end of the spring, as long as it only has a mounting surface for the attachment part. The attachment part is specifically designed such that the retaining projection is located in the area of ​​the base plate of the housing. This allows the first spring to be dimensioned as long as possible and to be arranged utilizing the entire free space between the locking lever and the base plate.

[0017] The retaining element can preferably be designed such that it extends the base plate towards the outside. The retaining element thus forms an extended extension of the base plate, allowing the attachment points of the first spring to be positioned opposite each other on the lever arm of the locking lever and on the retaining element, creating a space between them.

[0018] It is further proposed that the first spring be formed by a cylindrical helical spring, and that the projection deflects the first spring laterally transversely to its longitudinal extent. The proposed design of the first spring offers the advantage of pre-tensioning it by deflecting it laterally without compromising its desired properties regarding the preload of the locking lever arm. The projection pre-tensions the first spring transversely to the direction in which its spring force is exerted on the lever arm. This has the advantage that the preload of the first spring via the projection is deliberately not, or only partially, directed in the direction in which the spring force is exerted on the lever arm. Therefore, the spring force exerted by the first spring on the lever arm is never reduced and is, if at all, increased.

[0019] It is further proposed that the projection is formed by a cam with a curved contact surface. The first spring is pre-tensioned by the projection and thereby forced into a curved shape. The projection's curved contact surface is adapted to this curved shape of the first spring, so that the first spring is forced into the pre-tensioned shape by the projection as gently as possible and with forces that are as localized as possible. The contact surface is curved in the same direction as the curvature of the first spring when it is in contact with the projection.

[0020] It is further proposed that the first spring have an elastic plastic coating, at least in the area where it contacts the projection. This elastic plastic coating further reduces noise generated when the first spring moves towards the projection by dampening the noise upon contact. It also protects the first spring from external mechanical influences.

[0021] The invention is explained below with reference to a preferred embodiment and the accompanying figures. Fig. 1 shows an electrically actuated locking device according to the prior art in an exploded view; and Fig. 2 shows an electrically actuated locking device according to the prior art with a locking lever in two different positions in a sectional view; and Fig. 3 shows a belt retractor according to the prior art with a locking device according to the Figures 1 and 2 with a blocked and a released belt shaft; and Fig. 4 a further developed blocking device according to the invention in perspective view; and Fig. 5 a further developed blocking device according to the invention in side view; and Fig. 6 a further developed blocking device according to the invention in sectional view; Fig. 7 a further developed blocking device according to the invention without blocking lever.

[0022] In the Figures 4 to 6 A further developed electrical locking device 100 can be identified, which integrates the locking device 100 into the Figures 1 to 2in the seatbelt retractor of the Fig. 3 to implement the belt retractor according to the invention. The blocking device 100 of the Figures 4 to 5 differs from the blocking device 100 of the Figures 1 and 2 by providing an additional second raised leg 17 on the base plate 15 of the housing 1, which, when the locking lever 2 is engaged, closes a second magnetic circuit II via the first raised leg 16 according to the same principle as the first magnetic circuit I, thereby increasing the pulling force of the locking lever 2. For this purpose, instead of the single magnetic iron core 12 in the locking device 100, the Figures 1 and 2Two separate iron cores 12a and 12b are provided. Furthermore, the damping element 13 is omitted here, but can be added if further damping of the noise and movement of the locking lever 2 is desired. Additionally, a second spring (not shown) can be provided, which acts directly on the locking arm 23 and is positioned so that it is tensioned when the locking lever 2 is pulled towards the housing 1. This tension assists the pivoting movement of the locking lever 2 and thus reduces the locking time of the belt shaft 20. Furthermore, the locking lever 2 can be further tensioned in this way, further reducing its uncontrolled movements.

[0023] The further developed blocking device 100 according to the Figures 4 to 6The projection 200 comprises a projection 200 which bears laterally against the first spring 4 and forces it into a curved position. The projection 200 thereby tensions the first spring 4 transversely to its longitudinal extent. The projection 200 is integrally formed on an extension 203, which is attached laterally to the raised first leg 16 of the housing 1. The extension 203 is a plastic part, preferably an elastomer, preferably of the Hytrel type, and is shaped such that it extends to the base plate 15 of the housing 1. The extension 203 further comprises a retaining projection 202, which projects outwards from the housing 1 of the locking device 100 in the same direction as the lever arm 22 of the locking lever 2. The retaining projection 202 is positioned such that it extends the base plate 15 of the housing 1 outwards and thus forms a counter-bearing opposite the lever arm 22.The first spring 4 is implemented as a cylindrical helical spring, which is fixed at its first upper end (as shown in the illustration) to the lever arm 22 of the locking lever 2 and at its second lower end to the retaining projection 202. The first spring 4 is designed such that, in the locked position, it exerts a tensile force on the lever arm 22 and thereby moves the locking lever 2 into the... Figures 4 to 6The spring 4 is pre-tensioned in the position shown. Simultaneously, it rests laterally against a curved contact surface 201 of the projection 200 and is thereby curved laterally and additionally pre-tensioned transversely to the tensile force it exerts on the lever arm 22. Due to the helical shape of the first spring 4, the tensile force exerted by it on the lever arm 22 is directed along its longitudinal axis. The projection 200 rests laterally against the first spring 4 and deforms it perpendicular to its longitudinal direction. This further tensions the first spring 4 and increases the tensile force acting within it. Thus, the first spring 4 is further pre-tensioned, and the tensile force exerted on the lever arm 22 is increased.Due to the deformation of the first spring 4 caused by the projection 200, it rests against the curved contact surface 201 of the projection 200, regardless of the position of the locking lever 2, and is therefore unable to make any or only very minor noise-generating movements relative to the locking device 100. Furthermore, the extension 203 extends to the base 15 of the housing 1 and, together with the retaining projection 202, forms a support located in the area of ​​the base 15 of the housing 1, to which the second end of the first spring 4 is attached. This allows the use of a first spring 4 with the maximum possible length.

[0024] The projection 200 is formed on an attachment part 203, which is fastened to the housing 1, so that the housing 1, apart from the fastening of the attachment part 203, does not require any special shaping to realize the projection 200. Furthermore, the projection 200 is provided with a curved contact surface 201, the curvature of which is aligned with the curvature of the first spring 4 in the area where the projection 200 rests, so that the projection 200 bears against the curved first spring 4 with an enlarged area. Furthermore, the projection 200 can be formed on the attachment part 203 from a different material than the housing 1.The housing 1 is preferably made of a magnetic material, preferably a ferromagnetic metal, to realize the magnetic circuits I and II, while the attachment part 203 is formed here by a plastic, preferably an elastomer of the Hytrel type, which has the necessary dimensional stability for the deflection of the first spring 4 and at the same time has damping properties with regard to noise generation due to its elastic properties.

[0025] Furthermore, the first spring 4 can be additionally provided with an elastic plastic coating, which can further reduce noise generation.

[0026] In the Figure 7The further developed locking device 100 is shown without the locking lever 2. The upper radial flange 8 is additionally provided with an upwardly projecting lug 27, which is arranged centrally on an edge of the radial flange 8 facing the second raised leg 17 and has an elongated shape aligned parallel to the edge. Furthermore, the first raised leg 16 is provided with two raised, spaced-apart lugs 18 and 19. The lugs 18 and 19 on the first raised leg 16 and the lug 27 on the radial flange 8 together form a three-point support for the locking lever 2 in the tightened position, so that the locking lever 2 cannot perform any tilting movements in the tightened position.

Claims

1. Belt retractor, comprising - a rotatably mounted belt shaft (20) and - a toothed control disk (21) rotatably mounted thereon and - an electrically actuatable blocking device (100) comprising - a housing (1) comprising a base plate (15) and an upright first limb (16) and - a blocking lever (2) which is pivotably mounted in a pivot bearing of the upright first limb (16) and comprises a steel plate (5), - the electrically actuatable blocking device (100) stopping the control disk (21) with respect to the belt shaft (20) as a result of the blocking lever (2) engaging in the toothing (26) the control disk (21), and said blocking device as a result forcing a blocking pawl to perform a movement in which it comes into engagement in a toothing of the belt retractor, which toothing is fastened to the vehicle, and blocks the belt shaft in the pull-out direction, - the blocking lever (2) having a lever arm (22) which projects outwardly from the first limb (16) and on which a first spring (4) engages by means of a first end, which spring preloads the blocking lever (2) into a position in which said blocking lever engages in the toothing (26) of the control disk (21) by means of a blocking tip (25) arranged at the end of a blocking arm (23), and said blocking device also comprising - an electromagnet (3) arranged in the housing (1), which electromagnet exerts a force on the blocking lever (2) as a result of being energized, as a result of which force said blocking lever is pulled out of the toothing (26) of the control disk (21) by means of the blocking tip (25), characterized in that - a protrusion (200) is provided on the housing (1), which protrusion is shaped in such a way that the first spring (4) bears against it regardless of the position of the blocking lever (2) and is pretensioned transversely to the spring force exerted on the lever arm (22).

2. Belt retractor according to claim 1, characterized in that - the first spring (4) is held in the region of the base plate (15) by means of a second end, and - the protrusion (200) is arranged on the first limb (16) of the housing (1), which limb projects upright from the base plate (15).

3. Belt retractor according to either of claims 1 and 2, characterized in that - the protrusion (200) is molded onto an attachment part (203) held on the housing (1).

4. Belt retractor according to claim 3, characterized in that - the attachment part (203) has a holding attachment (202) arranged in the region of the base plate (15), and - the first spring (4) is held on the holding attachment (202) by means of the second end of said spring.

5. Belt retractor according to claim 4, characterized in that - the holding attachment (202) extends the base plate (15) toward the outside.

6. Belt retractor according to any of claims 1 to 5, characterized in that - the first spring (4) is formed by a cylindrical helical spring, and the protrusion (200) laterally deflects the first spring (4) transversely to the longitudinal extension thereof.

7. Belt retractor according to any of claims 1 to 6, characterized in that - the protrusion (200) is formed by a cam with a curved bearing surface (201).

8. Belt retractor according to any of claims 1 to 7, characterized in that - the first spring (4) has an elastic sheath, made of a plastics material, at least in the region where it bears against the protrusion (200).