Seatbelt retractor with an electrically operated locking device

Abstract

Seatbelt retractor with -a rotatably mounted belt shaft (20) and -a toothed control disc (21) rotatably mounted thereon and -an electrically operated locking device (100) with -a housing (1) with a base plate (15) and a raised first leg (16), and -a locking lever (2) pivotably mounted in a pivot bearing of the raised first leg (16) with a steel plate (5), wherein -the electrically actuated locking device (100) stops the control disc (21) relative to the belt shaft (20) by means of an engagement of the locking lever (2) in the toothing (26) and thereby forces a locking pawl to move in which it engages in a vehicle-fixed toothing of the belt retractor and blocks the belt shaft in the extension direction, wherein -the locking lever (2) has a lever arm (22) projecting outwards from the first leg (16), on which a first spring (4) acts with a first end, which biases the locking lever (2) into the position in which it engages with a locking tip (25) arranged at the end of a locking arm (23) in the toothing (26) of the control disc (21), and -an electromagnet (3) arranged in the housing (1), which exerts a force on the locking lever (2) by means of a current, by which it is pulled out of the toothing (26) of the control disk (21) with the locking tip (25), characterized in that -a projection (200) is provided on the housing (1) which is shaped in such a way that the first spring (4) rests against it regardless of the position of the locking lever (2) and is pre-tensioned transversely to the spring force exerted on the lever arm (22), wherein -the first spring (4) is formed by a cylindrical helical spring, and the projection (200) deflects the first spring (4) laterally transversely to its longitudinal extent.

Description

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

[0002] A generic electrically actuated blocking device is known, for example, from GB 2 398 824 A or WO 2021 / 047 982 A1.

[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 engagement of a blocking lever relative to the belt shaft and thereby force a blocking pawl to move into a toothing fixed to the vehicle, which in turn blocks the belt shaft in the extension direction.

[0004] In conventional mechanical locking devices, such as those known from DE 693 16 678 T2, an inertial mass is mounted on a contact surface. This mass is deflected when a predetermined vehicle deceleration is exceeded, thereby deflecting the locking lever and forcing it to engage the toothing 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 belt retractor, so that the belt shaft is not inadvertently blocked.This means that the belt retractor must be designed for each individual vehicle. The alignment of the contact surface and the mass resting on it in relation to the belt retractor must be individually designed so that it corresponds to the specified alignment, taking into account the installation geometry of the belt retractor in the vehicle. Furthermore, with belt retractors integrated in the front seats, such as in convertibles, there is the problem that the inertial mass is inadvertently deflected on the contact surface when the angle of the backrest is adjusted or when the backrest is folded forward to allow access to the rear seats. This causes the blocking lever to inadvertently move into the external toothing of the control disc. This blocks the belt retractor in the extension direction and the backrest cannot be swivelled any further, or the occupant cannot fasten their seat belt. To avoid this, additional switch-off mechanisms orCompensating mechanisms must be provided, but these must only be effective in these cases, so that the occupant is restrained in the event of an accident. These challenges make such a mechanical locking device very complex.

[0005] In the case of an electrically actuated blocking device, as known from GB 2 398 824 A or WO 2021 / 047 982 A1, for example, the movement of the blocking lever is electrically controlled, which eliminates the previously required inertial mass. The belt retractor can therefore be mounted unchanged in various positions in the vehicle and also in backrests. Furthermore, the blocking of the belt shaft can be controlled by an electrical signal originating from a control device. The signal can be generated by a control device, which can also generate the signal as a function of other sensor devices or control systems. For example, it is conceivable to block the belt shaft automatically when a driving dynamics assistance system is activated, which is controlled, for example, as a function of a signal from an optical sensor device.This also controls the electrical locking device directly or indirectly depending on the signal from the optical sensor device. Furthermore, the electrically actuated locking device can be operated 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. It can therefore also be preferably installed in seats of at least partially autonomous vehicles, which the occupant can adjust over considerably larger adjustment ranges for improved communication with other occupants, for alignment in a rest position, or generally to utilize the freedom gained through autonomous driving, compared to seats in conventional, non-autonomous vehicles.

[0006] An electrically actuated blocking device 100 used by the applicant in its products, which corresponds to the embodiment of GB 2 398 824 A, is described in the Fig. 1 and Fig. 2 as a single part and in the Fig. 3 on a belt retractor. The electrically actuated blocking device 100 comprises as basic elements a housing 1 with an L-shaped basic structure with a base plate 15 and a first upright leg 16, a blocking lever 2 pivotally mounted on the first upright leg 16 of the housing 1, an electromagnet 3 and a first spring 4, which is held at one end on the housing 1 and is connected at the other end to a lever arm 22 of the blocking lever 2 projecting outward from the first upright leg 16. The first spring 4 is designed as a tension spring such that it preloads the blocking lever 2 into a position in which it engages with a blocking tip 25 in a toothing 26 of a control disk 21 and thereby holds the control disk 21 relative to the belt shaft 20. The control disk 21 with the toothing 26 is only in the Fig. 3 in a belt retractor. When the belt shaft 20 rotates in the extension direction, the blocking pawl is automatically forced to engage a toothing fixed to the vehicle, and the belt shaft 20 is subsequently blocked against further belt webbing extension. The blocking lever 2 comprises a contoured part 24 and a steel plate 5, wherein the steel plate 5 faces the electromagnet 3, so that when the electromagnet 3 is energized, the blocking lever 2 is attracted by it and thus pulled out of the toothing 26 of the control disk 21. The belt shaft 20 can therefore subsequently rotate freely in the extension and retraction directions. The advantage of this solution is that the belt shaft 20 is 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 too.

[0007] The electromagnet 3 comprises a base component 6 with a columnar central section 7 and two radial flanges 8, one of which projects radially outward 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 passage section 14 in the central section 7 and an annular intermediate space 9 radially outward on the central section 7, wherein the annular intermediate space 9 is delimited towards the ends of the central section 7 by the radial flanges 8. The electromagnet 3 further comprises a coil 10 with a plurality of turns, which is arranged in the annular intermediate space 9 and is electrically contacted with an external control device via lines 11 provided in the base component 6.In addition, the electromagnet 3 comprises a first iron core 12 which is arranged in the tubular passage section 14 of the base component 6 and has a free end facing the steel plate 5 of the blocking lever 2.

[0008] When the coil 10 is energized, the blocking lever 2 is attracted by closing a first magnetic circuit I, defined by the first upstanding leg 16 of the housing 1, the first iron core 12 and the sections of the blocking lever 2 and the base plate 15 between the first iron core 12 and the first upstanding leg 16, as shown in the right-hand illustration of the Fig. 2 can be seen. Furthermore, a damping element 13 in the form of a soft tube, e.g. in the form of a short piece of hose, is provided, which is clamped at its ends between two extensions of the radial flange 8 facing the blocking lever 2. The damping element 13 is positioned so that the blocking lever 2 does not rest with its free end on the damping element 13 in the deflected position (left illustration of the Fig. 2) and only in the tightened position does it come into contact with the central soft section of the damping element 13 between the clamping points (right illustration of the Fig. 2). This dampens the tightening movement of the locking lever 2 in the final phase of the movement. This dampening creates a soft stop and prevents annoying "rattling noises" during the tightening movement and possible subsequent slight 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 structure.

[0010] To achieve this object, a belt retractor having the features of claim 1 is proposed. Further preferred embodiments of the invention can be found in the subclaims, the figures, and the associated description.

[0011] According to the basic concept of the invention, it is proposed that a projection be provided on the housing, which is shaped such that the first spring rests against it regardless of the position of the blocking lever and is preloaded transversely to the spring force exerted on the lever arm. 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 extension.

[0012] The proposed solution additionally pre-tensions the first spring and thus fixes it against uncontrolled movements, thereby reducing noise generated by preventing physical contact between the first spring and the adjacent parts of the blocking device. The spring is pre-tensioned regardless of the position of the blocking lever, so that the first spring is tensioned by the projection both when the blocking lever is deflected (i.e. when the belt shaft is blocked) and when the blocking lever is pulled (i.e. when the belt shaft is released). The first spring rests on the projection in such a way that it is pre-tensioned transversely to the spring force it exerts on the lever arm, so that the movement of the lever arm has no influence, or only the smallest possible influence, on the pre-tension exerted by the projection on the first spring.The proposed design of the first spring offers the advantage of preloading the first spring by deflecting it laterally without losing its desired properties with regard to preloading the lever arm of the locking lever. The first spring is preloaded by the projection 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 directed, or only partially directed, in the direction in which the spring force is exerted on the lever arm. This means that the spring force exerted by the first spring on the lever arm is not reduced in any way, but rather increased if possible.

[0013] The key advantage of the proposed solution is that the first spring, which triggers the movement of the locking lever, is directly restricted in its movement behavior. This reduces noise generation as close as possible to its source, where the first spring is clamped to the locking lever and the housing. The preload of the first spring not only increases the clamping force of the first spring in the connection between the locking lever and the housing, but also reduces possible transverse movements of the first spring, thus reducing the likelihood of the first spring striking adjacent components of the locking device and the associated potential noise generation.

[0014] It is further proposed that the first spring is held by a second end in the region of the base plate, and that the projection is arranged on the first leg of the housing projecting up from the base plate. The first spring thus extends laterally on the blocking device from the base plate to the lever arm of the blocking lever, so that the first leg to the side of the first spring offers a structurally simple surface on which the projection can be arranged. Furthermore, the first spring offers, in the region between the holder on the lever arm and in the region of the base plate, an intermediate section that is as long and freely accessible as possible, against which the projection can come into contact and via which the first spring can be tensioned.

[0015] It is further proposed that the projection be molded onto an attachment part attached to the housing. This eliminates the need to modify the housing itself, as long as it already has a sufficient attachment surface for attaching the attachment part. Furthermore, the attachment part can be individually shaped to form the projection and aligned in its attachment such that the first spring, through its attachment to the blocking device, automatically comes into contact with it and is preloaded according to the invention.

[0016] The attachment part can preferably have a holding attachment arranged in the region of the base plate, and the first spring can be held by its second end on the holding attachment. The attachment part thus also serves to fasten the second end of the spring, which offers the advantage that the projection and the fastening attachment of the first spring for its second end are realized on one and the same part and are thus arranged in a fixed spatial relationship to one another. Furthermore, the housing does not have to be designed either to form the projection or to fasten the second end of the spring, as long as it only has one attachment surface for the attachment part. The attachment part is specifically designed so that the holding attachment is arranged in the region of the base plate of the housing. This allows the first spring to be made as long as possible and to be arranged so that the entire free space between the blocking lever and the base plate is utilized.

[0017] The retaining projection can preferably be designed such that it extends the base plate toward the outside. The retaining projection thus forms an extended projection of the base plate, so that the fastening points of the first spring on the lever arm of the blocking lever and on the retaining projection can be arranged opposite one another, forming a free space therebetween.

[0018] It is further proposed that the projection be formed by a cam with a curved contact surface. The first spring is preloaded by the projection and thereby transformed into a curved shape. The projection is adapted to this curved shape of the first spring by its curved contact surface, so that the first spring is forced into the preloaded shape by the projection as gently as possible and with the most localized forces possible. For this purpose, the contact surface is curved in the same direction as the curvature of the first spring when it rests against the projection.

[0019] It is further proposed that the first spring have an elastic plastic sheathing, at least in the area where the projection contacts it. The elastic plastic sheathing can further reduce noise generated when the first spring moves toward the projection, as the elastic plastic sheath dampens the noise upon contact. Furthermore, the first spring can be protected from external mechanical influences.

[0020] The invention will be explained below using a preferred embodiment with reference to the attached figures. Fig. 1 an electrically actuated blocking device according to the prior art in an exploded view; and Fig. 2 shows an electrically actuated blocking device according to the prior art with a blocking lever in two different positions in a sectional view; and Fig. 3 a belt retractor according to the state of the art with a blocking device according to the Fig. 1 and Fig. 2 with one blocked and one released belt shaft; and Fig. 4 shows a perspective view of a blocking device further developed according to the invention; and Fig. 5 a blocking device further developed according to the invention in a side view; and Fig. 6 a blocking device further developed according to the invention in a sectional view; Fig. 7 a further developed blocking device according to the invention without a blocking lever.

[0021] In the Fig. 4 to 6, a further developed electrical blocking device 100 can be seen, which the blocking device 100 in the Fig. 1 to 2 in the belt retractor of the Fig. 3 to implement the belt retractor according to the invention. The blocking device 100 of the Fig. 4 to 5 differs from the blocking device 100 of the Fig. 1 and Fig. 2 in that a second upstanding leg 17 is additionally provided on the base plate 15 of the housing 1, which, when the blocking lever 2 is attracted, closes a second magnetic circuit II according to the same principle as the first magnetic circuit I via the first upstanding leg 16, whereby the attraction force of the blocking lever 2 can be increased. For this purpose, instead of the one magnetic iron core 12 in the blocking device 100 of the Fig. 1 and Fig. 2, two separate iron cores 12a and 12b are provided. Furthermore, the damping element 13 is omitted here, but can also be provided additionally if the noise development and movement behavior of the blocking lever 2 are to be further dampened. Furthermore, a second spring (not shown) can be provided, which acts directly on the blocking arm 23 and is positioned such that it is tensioned when the blocking lever 2 is pulled towards the housing 1 and supports the pivoting movement of the blocking lever 2, thereby shortening the locking time of the belt shaft 20. Furthermore, the blocking lever 2 can be further tensioned so that its uncontrolled movements can be further reduced.

[0022] The further developed blocking device 100 according to the Fig. 4 to 6 comprises a projection 200, which rests laterally against the first spring 4 and urges it into a curved position. The projection 200 tensions the first spring 4 transversely to its longitudinal extent. The projection 200 is formed on a projection 203, which is laterally attached to the upstanding first leg 16 of the housing 1. The projection 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 projection 203 further comprises a retaining projection 202, which projects outward from the housing 1 of the blocking device 100 in the same direction as the lever arm 22 of the blocking lever 2. The retaining projection 202 is positioned such that it extends the base plate 15 of the housing 1 towards the outside and thus forms an abutment opposite the lever arm 22.The first spring 4 is implemented as a cylindrical helical spring, which is secured with its first end (upper end in the illustration) to the lever arm 22 of the blocking lever 2 and with its second, lower end to the retaining projection 202. The first spring 4 is designed such that, in the secured position, it exerts a tensile force on the lever arm 22 and thereby forces the blocking lever 2 into the position shown in the. Fig. 4 to 6. At the same time, it rests laterally against a curved contact surface 201 of the projection 200 and is thereby laterally curved and additionally pre-tensioned transversely to the tensile force exerted by it on the lever arm 22. The tensile force exerted by the first spring 4 on the lever arm 22 is formed in the direction of its longitudinal axis due to the helical shape of the first spring 4. The projection 200 rests laterally against the first spring 4 and deforms the first spring 4 orthogonal to its longitudinal direction. As a result, the first spring 4 is additionally tensioned and the tensile force acting in the first spring 4 is additionally increased. The first spring 4 is thus additionally 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, the spring rests against the curved contact surface 201 of the projection 200, regardless of the position of the blocking lever 2, and can therefore perform no or only very slight noise-causing movements toward the blocking device 100. Furthermore, the extension part 203 extends to the base surface 15 of the housing 1 and, together with the retaining projection 202, forms an abutment arranged in the region of the base surface 15 of the housing 1, to which the first spring 4 is attached by its second end. This allows the use of a first spring 4 with the maximum possible length.

[0023] The projection 200 is implemented on an attachment part 203, which is fastened to the housing 1, so that the housing 1 requires no special shaping apart from the attachment of the attachment part 203 to implement 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 region of the contact of the projection 200, so that the projection 200 bears against the curved first spring 4 with an enlarged surface. Furthermore, the projection 200 can be implemented on the attachment part 203 using a different material than the housing 1.To realize the magnetic circuits I and II, the housing 1 is preferably made of a magnetic material, preferably of a ferromagnetic metal, while the attachment part 203 is formed here by a plastic, preferably by 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 development due to its elastic properties.

[0024] Furthermore, the first spring 4 can additionally be provided with an elastic plastic sheath, whereby the noise development can be further reduced.

[0025] In the Fig.7 shows the further developed blocking device 100 without the blocking lever 2. The upper radial flange 8 is additionally provided with an upwardly projecting nose 27, which is arranged centrally on an edge side of the radial flange 8 facing the second upright leg 17 and has an elongated shape aligned parallel to the edge side. Furthermore, the first upright leg 16 is provided with two upright, spaced-apart noses 18 and 19. The noses 18 and 19 on the first upright leg 16 and the nose 27 on the radial flange 8 together form a three-point support for the blocking lever 2 in the tightened position, so that the blocking lever 2 cannot perform any tilting movements in the tightened position.

Claims

[1] Belt retractor with -a rotatably mounted belt shaft (20) and -a toothed control disc (21) rotatably mounted thereon and -an electrically actuated blocking device (100) with -a housing (1) with a base plate (15) and an upstanding first leg (16), and -a blocking lever (2) with a steel plate (5) pivotably mounted in a pivot bearing of the upright first leg (16), wherein -the electrically actuated blocking device (100) stops the control disc (21) relative to the belt shaft (20) by an engagement of the blocking lever (2) in the toothing (26) and thereby forces a blocking pawl to move in which it engages in a toothing of the belt retractor fixed to the vehicle and blocks the belt shaft in the extension direction, wherein -the blocking lever (2) has a lever arm (22) projecting outwards from the first leg (16), on which a first spring (4) engages with a first end, which pre-tensions the blocking lever (2) into the position in which it engages with a blocking tip (25) arranged at the end of a blocking arm (23) in the toothing (26) of the control disc (21), and -an electromagnet (3) arranged in the housing (1) which, when energised, exerts a force on the blocking lever (2) by which it is pulled out of the toothing (26) of the control disc (21) with the blocking tip (25), characterized by , that -a projection (200) is provided on the housing (1), which projection is shaped such that the first spring (4) rests against it regardless of the position of the blocking lever (2) and is prestressed transversely to the spring force exerted on the lever arm (22), wherein -the first spring (4) is formed by a cylindrical helical spring, and the projection (200) deflects the first spring (4) laterally transversely to its longitudinal extent. [2] Belt retractor according to claim 1, characterized by , that -the first spring (4) is held with a second end in the region of the base plate (15), and -the projection (200) is arranged on the first leg (16) of the housing (1) projecting upwards from the base plate (15). [3] Belt retractor according to one of claims 1 or 2, characterized by , that -the projection (200) is formed onto an attachment part (203) held on the housing (1). [4] Belt retractor according to claim 3, characterized by , 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 with its second end on the holding projection (202). [5] Belt retractor according to claim 4, characterized by, that -the retaining projection (202) extends the base plate (15) towards the outside. [6] Belt retractor according to one of claims 1 to 5, characterized by , that -the projection (200) is formed by a cam with a curved contact surface (201). [7] Belt retractor according to one of claims 1 to 6, characterized by , that -the first spring (4) has an elastic plastic sheath at least in the area of ​​the projection (200).

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