Seat belt retractor having an electrically actuatable blocking device

Abstract

The seat belt retractor comprises a seat belt shaft, a control cam (21) mounted on the seat belt shaft, and an electrically operable locking device (100). The electrically operable locking device (100) stops the control cam (21) relative to the seat belt shaft (20) by engagement of a locking lever (2) with a tooth profile system (26) of the control cam (21), as a result of which the locking pawl is forced to perform the movement through which it engages with a tooth profile system fixed to the vehicle, preventing the seat belt shaft in the pulling-out direction. The locking lever (2) has a lever arm (22) protruding outwardly from a first rim (16). At a first end, a first spring (4) acts on the lever arm (22). The first spring (4) preloads the locking lever (2) to a position where the locking lever (2) engages a locking tip (25) arranged at an end of a locking arm (23) with the tooth profile system (26) of the control cam (21). Further, a protrusion (200) is provided on the housing (1) of the locking device. The protrusion is shaped such that the first spring (4) abuts against the protrusion regardless of the position of the locking lever (2), and a lateral preload is applied to the first spring with respect to the spring force exerted on the lever arm (22).

Description

Technical Field

[0001] The present invention relates to a seat belt having an electrically operable blocking device having the features of the preamble part of claim 1.

[0002] An electrically operable blocking device of this type is known, for example, from British Patent Application Publication No. 2398824(A).

[0003] Such a blocking device is used to stop an externally toothed control cam rotatably mounted on the seat belt shaft of a seat belt retractor relative to the seat belt shaft by engagement of a blocking lever, and as a result, to force a locking pawl to perform a control movement to a toothed system fixed to the vehicle, and as a result, the seat belt shaft is blocked in the pulling-out direction.

[0004] In a conventional mechanical locking device, an inert mass is applied to a contact surface, which deflects when a predetermined vehicle deceleration is exceeded, thereby deflecting a locking lever and engaging the locking lever with a tooth profile system of a control cam. Such a mechanical locking device is also referred to as a vehicle sensing sensor device. One problem with these mechanical locking devices is that the inert mass must always be aligned in an orientation defined on the contact surface with respect to the longitudinal axis and the transverse axis of the vehicle, regardless of the installation geometry of the seat belt retractor, so that the seat belt shaft is not inadvertently locked. Therefore, the seat belt retractor must be designed to be individual with respect to the vehicle in that the orientation of the contact surface and the mass applied to the contact surface with respect to the seat belt retractor are designed individually to correspond to a predetermined orientation taking into account the installation geometry of the seat belt retractor within the vehicle. Further, in the case of a seat belt retractor integrated into the front seat, for example, in the case of a convertible, when the tilt angle of the backrest is adjusted to access the rear seat, or when the backrest is folded forward, the inert mass inadvertently deflects onto the contact surface, resulting in the problem that the locking lever is inadvertently pushed into the tooth profile system of the control cam for controlled movement. Therefore, the seat belt retractor is locked in the pulling-out direction, the backrest can no longer pivot further, or the occupant cannot wear the seat belt. To prevent this, additional release or compensation mechanisms must be provided, but these mechanisms can only act in these cases so that the restraint of the occupant is guaranteed in all cases in the event of an accident. As a result of achieving these objectives, this type of mechanical locking device is mechanically very complex.

[0005] In the case of an electrically actuable locking device, in contrast, the movement of the locking lever is electrically controlled, as is known, for example, from UK Patent Application Publication No. 2398824(A), with the result that the previously required inert mass is omitted. This allows the seat belt retractor to be installed without change at different installation positions within the vehicle and within the backrest. Further, the locking of the seat belt shaft can be controlled by an electrical signal proceeding from a control device. In this case, the signal can be generated by the control device, which can also generate the signal in response to other sensor devices or control systems. For example, when a dynamic assistance system is activated, it is contemplated to automatically lock the seat belt shaft, and the dynamic assistance system is controlled, for example, in response to a signal from an optical sensor device. Thus, the electrically actuable locking device is also controlled directly or indirectly in response to a signal from the optical sensor device. Further, the electrically actuable locking device is not actuated by inertial forces and thus does not need to be oriented in a particular orientation with respect to the vehicle's travel direction and thus functions in any orientation and arrangement. Thus, it can preferably also be arranged on the seat of at least a semi-autonomous vehicle, and the occupant can adjust the seat to take advantage of the degree of freedom obtained by autonomous driving in a much wider adjustment range than was possible in the case of the seats of conventional non-autonomous vehicles, for improved communication with other occupants, for alignment in the stationary position, or generally.

[0006] An electrically operable blocking device 100, which is used by the applicant in that product and corresponds to the embodiment of UK Patent Application Publication No. 2398824(A), is shown as individual parts in FIGS. 1 and 2 and in FIG. 3 on a seat belt retractor. The electrically operable blocking device 100 basically comprises a housing 1 having an L-shaped basic structure with a base plate 15 and a first upright rim 16, a blocking lever 2 pivotally mounted on the first upright rim 16 of the housing 1, an electromagnet 3, and a first spring 4 held by one end of the housing 1 and connected by the other end of a lever arm 22 of the blocking lever 2 protruding outward from the first upright rim 16. The first spring 4 is designed as a tension spring. For this reason, the first spring 4 preloads the blocking lever 2 in a position where the blocking tip 25 engages the tooth profile system 26 of the control cam 21, whereby the control cam 21 holds the seat belt shaft 20 backward. The control cam 21 with the tooth profile system 26 can only be seen in FIG. 3 in the seat belt retractor. In this way, when the seat belt shaft 20 rotates in the pulling-out direction, the locking claw is automatically pushed into a tooth profile system fixed to the vehicle, and the seat belt shaft 20 is then blocked against further pulling out of the seat belt. The blocking lever 2 comprises a contour portion 24 and a steel plate 5. The steel plate 5 faces the electromagnet 3. For this reason, when the electromagnet is energized, the blocking lever 2 is attracted by the electromagnet 3 and thus pulled out from the tooth profile system 26 of the control cam 21. As a result, the seat belt shaft 20 can then rotate freely in both the pulling-out and pulling-in directions. The advantage of this solution is that even in the event of a power failure or a defect in the electromagnet 3, the seat belt shaft 20 is blocked in the pulling-out direction, and in this case too, the occupant is reliably restrained.

[0007] The electromagnet 3 comprises a base component 6 having a columnar central portion 7 and two radial flanges 8, one of the flanges 8 protruding radially outwards at one of the ends of the central portion 7 in each case. The electromagnet 3 is held on the base plate 15 of the housing 1 by the base component 6. The base component 6 has a tubular through portion 14 in the central portion 7 and has an annular intermediate space 9 radially on the outside above the central portion 7, the annular intermediate space 9 being limited towards the end of the central portion 7 by the radial flange 8. Furthermore, the electromagnet 3 comprises a coil 10 having a plurality of windings, the coil 10 being arranged in the annular intermediate space 9 and being in electrical contact with an external control device via a line 11 provided in the base component 6. In addition, the electromagnet 3 comprises a first iron core 12, the first iron core 12 being arranged in the tubular through portion 14 of the base component 6 and the 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 to close the first magnetic circuit I, which is defined by the first upright rim 16 of the housing 1, the first iron core 12, and the portion of the blocking lever 2 and the base plate 15 between the first iron core 12 and the first upright rim 16, as can be seen in the right diagram of FIG. 2. Furthermore, a damping element 13 is provided in the form of an essentially flexible tube, for example in the form of a short tube piece, 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 such that the free end of the blocking lever 2 does not press against the damping element 13 in the deflected position (left diagram of FIG. 2) and rests only on the central soft portion of the damping element 13 between the clamping points in the attracted position (right diagram of FIG. 2). As a result, the attracting movement of the blocking lever 2 is damped in the final stage of the movement. As a result of this damping, a soft stop is achieved and disturbing "rattling noises" are avoided during the attracting movement of the blocking lever 2 and any subsequent slight movement that may occur.

[0009] An object of the present invention is to provide a general type of seat belt retractor in which noise generation is reduced and the basic structure is simplified.

[0010] In order to achieve the object, a seat belt retractor having the features of claim 1 has been proposed. Further, preferred embodiments of the present invention are obtained from the dependent claims, the figures, and the related description.

[0011] According to the basic concept of the present invention, it is proposed that the protrusion is provided on the housing, and the protrusion is pressed against the first spring regardless of the position of the blocking lever, and is shaped such that a preload is applied to the first spring in a lateral direction with respect to the spring force exerted on the lever arm.

[0012] The proposed solution additionally applies a preload to the first spring, thus fixing the first spring against uncontrolled movement, thereby reducing the noise generated by preventing physical contact between the first spring and the adjacent part of the blocking device. The spring is preloaded regardless of the position of the blocking lever. For this reason, the first spring is preloaded by the protrusion both when the blocking lever is in the deflected position (i.e., when the seat belt shaft is blocked) and when the blocking lever is retracted (i.e., when the seat belt shaft is released). The first spring is pressed by the protrusion such that a preload is applied to the first spring in a lateral direction with respect to the spring force exerted on the lever arm by the first spring. For this reason, the movement of the lever arm does not affect or minimally affects the preload applied to the first spring by the protrusion.

[0013] The decisive advantage of the proposed solution is that the movement behavior of the first spring that triggers the movement of the blocking lever is immediately restricted. This reduces the noise source when clamping the first spring to the blocking lever and the generation of noise as close as possible to the housing. The preload of the first spring not only results in an increase in the clamping of the first spring in its connection to the blocking lever and the housing, but also reduces the possible lateral movement of the first spring, and thus the possibility of the first spring colliding with adjacent components of the blocking device, and thus the associated potential noise generation.

[0014] In addition, the first spring is held in the region of the base plate by the second end, and the protrusion is arranged on the first rim of the housing protruding upward from the base plate. Thus, the first spring extends laterally on the blocking device from the base plate to the lever arm of the blocking lever, and for this reason, the first rim provides the first spring with a surface that is structurally easy to use and on which the protrusion can be arranged laterally. Furthermore, the first spring provides an intermediate portion that is freely accessible as long as possible between the holder on the lever arm and the region of the base plate, and the protrusion can contact this intermediate portion, and a load can be applied to the first spring via this intermediate portion.

[0015] It is further proposed that the protrusion is formed on a mounting part held on the housing. This means that no modification is necessary as long as the housing itself already has a sufficient mounting surface for fixing the mounting part. Furthermore, the mounting part can be individually molded to form the protrusion, and the first spring can be aligned when fixed so that it automatically contacts the blocking device due to its fixing and is preloaded according to the present invention.

[0016] The attachment part can preferably have a holding attachment part arranged in the area of the base plate, and the first spring can be held on the holding attachment part at its second end. Thus, the attachment part also serves to fix the second end of the spring, which provides the advantage that the protrusion and the fixing of the second end of the first spring are realized on one and the same part and are thus arranged in a mutually fixed spatial relationship. Furthermore, the housing need not be designed to form a protrusion or to attach the second end of the spring as long as it has only an attachment surface for the attachment part. The attachment part is specially designed such that the holding attachment part is arranged in the area of the base plate of the housing. Thereby, it becomes possible to make the first spring as long as possible and arrange it using the entire free space between the blocking lever and the base plate.

[0017] The holding attachment part can preferably be designed to extend the base plate outwards. Thus, the holding attachment part forms an extended lug of the base plate, and for this reason, the fixing points of the first spring on the lever arm of the blocking lever and on the holding attachment part can be formed opposite to each other, creating a free space between them.

[0018] The first spring is formed by a cylindrical helical spring, and it is further proposed that the protrusion deflect the first spring transversely with respect to its longitudinal extension. The proposed design of the first spring provides the advantage of preloading the first spring by deflecting it transversely without losing its desired characteristics regarding the preload of the lever arm of the blocking lever. In this case, the first spring is preloaded transversely by the protrusion with respect to the spring force it exerts on the lever arm, which has the advantage that the preload of the first spring via the protrusion is not intentionally directed or only partially directed in the direction of the spring force exerted on the lever arm by the first spring, and thus the spring force exerted on the lever arm by the first spring is never reduced and, if possible, increased.

[0019] It is further proposed that the protrusion is formed by a cam having a curved contact surface. The first spring is preloaded by the protrusion, thereby giving it a curved shape. The protrusion is adapted to this curved shape of the first spring by its curved contact surface, so that the first spring is pushed into the preloaded shape by the protrusion with as gentle and as localized a force as possible. For this purpose, the contact surface is curved in the same direction as the curvature of the first spring when the first spring contacts the protrusion.

[0020] It is further proposed that the first spring has an elastoplastic sheath at least in the region where it contacts the protrusion. The elastoplastic sheath can further reduce the noise generated when the first spring moves towards the protrusion by damping the noise when the first spring contacts the elastoplastic sheath. In addition, the first spring can be protected from external mechanical influences.

Brief Description of the Drawings

[0021] The present invention will be described below based on preferred embodiments with reference to the accompanying drawings. The drawings are as follows.

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0023] In FIGS. 4 to 6, in order to implement the seat belt retractor according to the present invention, a further developed electric blocking device 100 can be seen, which replaces the blocking device 100 of FIGS. 1 to 2 in the seat belt retractor of FIG. 3. A second upright rim 17 is additionally provided on the base plate 15 of the housing 1. When the blocking lever 2 is pulled, the second upright rim 17 closes the second magnetic circuit II according to the same principle as the first magnetic circuit I via the first upright rim 16. Therefore, the blocking device 100 of FIGS. 4 to 5 is different from the blocking device 100 of FIGS. 1 and 2 in that the attractive force of the blocking lever 2 can be increased. For this purpose, instead of one magnetic core 12 in the blocking device 100 of FIGS. 1 and 2, two separate cores 12a and 12b are provided. Furthermore, although the damping element 13 is omitted here, if the generation of noise and the movement behavior of the blocking lever 2 should be further damped, this damping element can be additionally provided. Furthermore, a second spring (not shown) can be additionally provided. This second spring acts directly on the blocking arm 23 and is positioned so as to be preloaded when the blocking lever 2 is pulled towards the housing 1, supporting the pivoting movement of the blocking lever 2, thereby shortening the locking time of the seat belt shaft 20. Furthermore, since more tension can be applied to the blocking lever 2 thereby, its uncontrolled movement can be further reduced. The further improved blocking device 100 according to FIGS. 4 to 6 includes a protrusion 200 that is laterally pressed against the first spring 4 and forces the first spring 4 into a curved position. The protrusion 200 applies a load to the first spring 4 in a direction transverse to its longitudinal extension. The protrusion 200 is formed on a mounting component 203 that is laterally attached to the upright first rim 16 of the housing 1. The mounting component 203 is a plastic component, preferably an elastomer, preferably of the Hytrel type, and is shaped to extend to the base plate 15 of the housing 1. The mounting component 203 further includes a retaining attachment portion 202 that protrudes 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 attachment portion 202 is positioned to extend the base plate 15 of the housing 1 outwardly, thus forming an abutment opposite to the lever arm 22. The first spring 4 is implemented by a cylindrical coil spring that is fixed to the lever arm 22 of the blocking lever 2 at its first end (the upper end in the illustrative drawing) and fixed to the retaining attachment portion 202 at its second lower end. The first spring 4 is designed such that in the fixed position, the first spring exerts a tensile force on the lever arm 22, thereby preloading the blocking lever 2 to the position shown in FIGS. 4 to 6. At the same time, it is laterally placed on the curved contact surface 201 of the protrusion 200, thereby being laterally curved and additionally preloading this first spring laterally against the tensile force exerted on the lever arm 22 by this first spring. The tensile force exerted on the lever arm 22 by the first spring 4 is exerted in the direction of its longitudinal axis due to the helical shape of the first spring 4. The protrusion 200 is laterally placed on the first spring 4 and deforms the first spring 4 at a right angle to its longitudinal direction. This additionally loads the first spring 4 and further increases the tensile force acting on the first spring 4. As a result, the first spring 4 is further pulled, and the tensile force exerted on the lever arm 22 increases.Due to the deformation of the first spring 4 caused by the protrusion 200, the curved contact surface 201 of the protrusion 200 is pressed against the first spring regardless of the position of the blocking lever 2. Thus, it is possible to prevent the movement that causes noise towards the blocking device 100 or to allow only very slight movement. Further, the mounting part 203 extends to the base surface 15 of the housing 1 and, together with the holding mounting part 202, forms an abutment arranged in the region of the base surface 15 of the housing 1. The first spring 4 is fixed to the abutment at its second end. Thereby, it becomes possible to use the first spring 4 having the maximum possible length.

[0024] The protrusion 200 is realized on a mounting part 203 fixed to the housing 1. For this reason, the housing 1 does not require any special molding apart from the fixing of the mounting part 203 to realize the protrusion 200. Further, the protrusion 200 is provided with a curved contact surface 201, and the curvature of this contact surface is matched with the curvature of the first spring 4 in the contact region of the protrusion 200. For this reason, the protrusion 200 is pressed against the first spring 4 curved with an enlarged surface. Further, the protrusion 200 can be realized on the mounting part 203 by a material different from that of the housing 1. To realize the magnetic circuits I and II, the housing 1 is preferably made of a magnetic material, preferably a ferromagnetic metal, while the mounting part 203 is here formed by a plastic, preferably an elastomer of the Hytrel type, which has the dimensional stability required for the deflection of the first spring 4 and at the same time has damping characteristics with respect to the generation of noise due to its elastic properties.

[0025] Furthermore, an elastic plastic sheath can be further provided on the first spring 4, and the generation of noise can be further reduced.

[0026] In FIG. 7, an even more improved blocking device 100 is shown without the blocking lever 2. The upper radial flange 8 is further provided with an upwardly protruding lug 27, which is arranged at the center of the side edge of the radial flange 8 facing the second upright rim 17 and has an elongated shape aligned parallel to the side edge. Further, two upright lugs 18 and 19 spaced apart from each other are provided on the first upright rim 16. The lugs 18 and 19 on the first upright rim 16 and the lug 27 on the radial flange 8 together form a three-point support for the blocking lever 2 in the retracted position, and for this reason, the blocking lever 2 cannot perform any tilting movement in the retracted position.

Claims

1. A seat belt retractor, a rotatably mounted seat belt shaft (20); a toothed control cam (21) rotatably mounted on the seat belt shaft; An electrically actuatable blocking device (100) comprising: a housing (1) having a base plate (15) and an upstanding first rim (16); a blocking lever (2) pivotally mounted in a pivot bearing of said upstanding first rim (16) and comprising a steel plate (5), the electrically actuatable blocking device (100) stops the control cam (21) against the seat belt shaft (20) by the engagement of the blocking lever (2) with the tooth system (26) of the control cam (21), thereby forcing a locking pawl to move for engagement with the tooth system of the seat belt retractor fixed to the vehicle and blocking the seat belt shaft in the withdrawal direction; a blocking lever (2) having a lever arm (22) projecting outward from the first rim (16), on which a first end of a first spring (4) acts, the first spring (4) preloading the blocking lever (2) into a position in which a blocking nose (25) arranged at the end of the blocking arm (23) engages with the tooth system (26) of the control cam (21); an electrically actuatable blocking device (100) comprising an electromagnet (3) arranged in the housing (1), which, when energized, exerts a force on the blocking lever (2), which pulls the blocking lever together with the blocking nose (25) out of the tooth system (26) of the control cam (21); a protrusion (200) is provided on the housing (1), the protrusion (200) being shaped so that the first spring (4) abuts against the protrusion regardless of the position of the blocking lever (2) and so that a preload is applied to the first spring in a direction transverse to the spring force exerted on the lever arm (22).

2. The first spring (4) is held at a second end in the region of the base plate (15), The protrusion (200) is disposed on the first rim (16) of the housing (1) that protrudes upward from the base plate (15).

2. The seat belt retractor according to claim 1, wherein:

3. The protrusion (200) is molded on a mounting part (203) held on the housing (1).

3. A seat belt retractor according to claim 1 or 2.

4. The mounting part (203) has a retaining mounting part (202) arranged in the region of the base plate (15), The first spring (4) is held at its second end on the holding mount (202).

4. The seat belt retractor according to claim 3, wherein:

5. The retaining attachment portion (202) extends the base plate (15) outward.

5. The seat belt retractor according to claim 4.

6. The first spring (4) is formed by a cylindrical helical spring, and the protrusion (200) deflects the first spring (4) laterally relative to its longitudinal extension.

3. A seat belt retractor according to claim 1 or 2.

7. The protrusion (200) is formed by a cam having a curved contact surface (201), 3. A seat belt retractor according to claim 1 or 2.

8. The first spring (4) has an elastic plastic sheath at least in the area in contact with the protrusion (200).

3. A seat belt retractor according to claim 1 or 2.

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