Seat belt retractor

Abstract

The present invention relates to a seat belt retractor, which comprises: a frame (1), a take-up spool (3) rotatably supported in the frame for winding a webbing (2); a force-limiting member (4) which fails when a predetermined load threshold is exceeded; a pretensioning device (10) having a drive wheel (6) coupled to the take-up spool via the force-limiting member, the drive wheel being drivable such that the take-up spool rotates in the webbing take-up direction to pretension the webbing; a locking stop member. The drive wheel is directly torsionally connected to the force-limiting member on a first side facing the take-up spool, and in addition to this torsional connection, the drive wheel is rotatably supported relative to the take-up spool, and the drive wheel is directly torsionally connected to the stop member on a second side facing away from the take-up spool. The drive wheel has a central hole which receives the force-limiting member on the first side facing the take-up spool and receives the stop member on the second side facing away from the take-up spool. The seat belt retractor has a compact structure and a stable force-limiting function.

Description

Technical Field

[0001] The present invention relates to the field of safety technology, and more particularly to a seat belt retractor. The seat belt retractor can be used in a means of transportation, especially a motor vehicle, such as a passenger car. Background Art

[0002] In a motor vehicle, a seat belt device is an important part of an occupant restraint system, and can provide protection for an occupant, especially in a traffic accident, to avoid or minimize the injury to the occupant. With the development and progress of motor vehicle technology, the requirements for the performance of the seat belt device are constantly increasing.

[0003] The seat belt device may have a seat belt retractor, which can be equipped with a vehicle sensing device and a locking mechanism, which are known in various forms in the prior art. The vehicle sensing device can sense a safety-related state of the motor vehicle, such as vehicle acceleration and / or vehicle tilt angle, and activate the locking mechanism under a predetermined condition, so that the spool is locked in the webbing pulling-out direction. The seat belt device may have a webbing sensing device, wherein the excessive pulling out of the webbing from the seat belt retractor may cause the spool to be locked in the webbing pulling-out direction. For the relevant prior art, reference can be made to, for example, patent documents CN109177915A and CN109159755A.

[0004] In addition, a seat belt device with a pretensioning function is known, which includes a pretensioning device. The pretensioning device can pretension the seat belt in an emergency of the vehicle to better restrain the vehicle occupant. The pretensioning device is also known in various forms in the prior art. For example, a pyrotechnic pretensioning device may include a ball gear and a gas generator, wherein when the gas generator is detonated, a plurality of steel balls are successively launched out, engage with the ball gear, so that the ball gear drives the spool to rotate in the webbing winding direction. In addition, a pretensioning device is also known, which has a serpentine flexible strip and a gear, the flexible strip can be pushed out and engaged with the gear, and thus drives the spool to rotate in the webbing winding direction. Generally, the pretensioning device is arranged on one side of the frame of the seat belt retractor, and the vehicle sensing device and the locking mechanism are arranged on the other side of the frame.

[0005] In some cases, the pretensioning device may provide an excessive pretensioning force when activated. After the pretensioning device takes effect, it is possible that the vehicle occupant is overly restrained, and the excessive peak value of the shoulder belt force of the webbing may cause injury to the vehicle occupant. For this reason, a force limiting device can be provided in the seat belt device, which can limit the load-bearing capacity of the seat belt retractor.

[0006] In the research, the inventors of the present invention found that in the prior art known from practice, it may be necessary to first overcome the pre-tightening force applied to the webbing spool by the pre-tightening device before the force-limiting device comes into play. In an emergency situation of a vehicle, during the force-limiting process immediately following the pre-tightening process, the shoulder strap force is uncertain. The seat belt retractor according to the prior art has a complex structure, a large number of parts, and high dimensional requirements for the parts in terms of assembly. Summary of the Invention

[0007] An object of the present invention is to provide a seat belt retractor having a force-limiting function and a pre-tightening function, which can have a compact structure, and the pre-tightening function at least basically does not affect the force-limiting function.

[0008] The above object can be achieved by a seat belt retractor, which includes:

[0009] A rotatably supported webbing spool for winding the webbing;

[0010] A force-limiting member configured to fail when a predetermined load threshold is exceeded;

[0011] A pre-tightening device having a drive wheel coupled to the webbing spool via the force-limiting member, the drive wheel being drivable such that the webbing spool coupled to the drive wheel rotates in the webbing winding direction to pre-tighten the webbing; and

[0012] A lockable stop member;

[0013] Wherein, the drive wheel is directly torsionally connected to the force-limiting member on a first side facing the webbing spool, and the drive wheel is rotatably supported relative to the webbing spool in addition to the torsional coupling between the drive wheel and the webbing spool via the force-limiting member; the drive wheel is directly torsionally connected to the stop member on a second side facing away from the webbing spool; the drive wheel has a central hole, and the central hole receives the force-limiting member on the first side facing the webbing spool and receives the stop member on the second side facing away from the webbing spool.

[0014] In some embodiments, the stop member is a stop wheel.

[0015] In this context, the expression "torsionally connected" may mean that the two connected components cannot or basically cannot rotate relative to each other. Due to the existence of unintentional gaps (such as due to manufacturing errors), or due to the existence of intentional gaps (such as due to a deliberately designed play of several degrees), or due to the elasticity of the various components of the entire connection system, the two connected components may be able to rotate slightly relative to each other or may rotate relative to each other with a predetermined play. For example, when two components are welded or bonded together, or press-fitted or integrally formed, they can rotate together, and thus they can be considered to be torsionally connected.

[0016] In some embodiments, the seat belt retractor may include a frame, and the webbing spool is rotatably supported in the frame.

[0017] The seat belt retractor may generally be used in a vehicle, such as for an aircraft, a ship, an amusement ride or a land vehicle, and in particular may be used in a motor vehicle such as a car.

[0018] In some embodiments, the force limiting member may be a force limiting rod.

[0019] In some embodiments, one end of the force limiting rod may be directly torsionally connected to the webbing spool, and the other end thereof may be directly torsionally connected to the drive wheel.

[0020] In some embodiments, when a predetermined torsional load threshold is exceeded, the force limiting rod may undergo plastic deformation.

[0021] In some embodiments, the force limiting rod may be cut off when a predetermined torsional load threshold is exceeded. For example, the force limiting rod may have a weak portion.

[0022] In some embodiments, when a predetermined torsional load threshold is exceeded, the torsional connection between the force limiting rod and the webbing spool and / or the drive wheel may be broken.

[0023] In some embodiments, the drive wheel may be a gear or a friction wheel.

[0024] In some embodiments, the central hole may be configured as a stepped hole, and the central hole may have a first hole section with a larger diameter, a second hole section with a smaller diameter, and a step between the first hole section and the second hole section.

[0025] In some embodiments, the stop member may have a first shaft section with a larger diameter, a second shaft section with a smaller diameter, a first shoulder on an end of the first shaft section facing away from the second shaft section, and a second shoulder between the first shaft section and the second shaft section.

[0026] In some embodiments, the first shaft section of the stop member may be received in the first hole section, the second shaft section of the stop member may be received in the second hole section, the first shoulder may abut against the drive wheel, the second shoulder may abut against the step of the central hole, and the second hole section may further receive the force limiting member.

[0027] In some embodiments, the stop member may be in form - fit connection with the drive wheel.

[0028] In some embodiments, the stop member may be torsionally connected directly to the drive wheel in the first and second shaft segments through a segmented spline in the first and second hole segments of the central hole, and / or the force limiting member may be torsionally connected directly to the drive wheel through a spline in the second hole segment of the central hole.

[0029] As an alternative or supplement to the form-fitting connection, the stop member and the drive wheel may be connected in a force-fitting and / or material-fitting manner, and / or the force limiting member and the drive wheel may be connected in a force-fitting and / or material-fitting manner.

[0030] In some embodiments, the stop member and the force limiting member may be in contact with each other or adjacent to each other in the second hole segment of the central hole.

[0031] In some embodiments, the drive wheel may have a hub on a first side facing the take-up spool, the take-up spool may have a stepped hole, and the hub may be rotatably supported in a hole segment with a larger diameter of the stepped hole of the take-up spool.

[0032] In some embodiments, the seat belt retractor may have a vehicle sensing device and / or a webbing sensing device that cooperate with the stop member.

[0033] In some embodiments, the drive wheel may be configured as a ball gear, the ball gear having teeth and ball sockets between the teeth, the pre-tensioning device including a gas generator and a set of drive steel balls that can be fired by the gas generated by the gas generator when the gas generator is triggered and can thus engage with the ball gear and drive the ball gear. Here, the term "drive steel ball" can generally be understood as a rolling body having an inertial mass, such as a sphere, ellipsoid or roller made of stainless steel, aluminum or other metallic material or made of composite material.

[0034] In some embodiments, the seat belt retractor may include a frame, such as a U-shaped frame, configured for mounting in a vehicle, and a structural unit including a take-up spool, a force limiting member, a drive wheel and a stop member is rotatably supported in the frame.

[0035] In some embodiments, the seat belt retractor may include a locking plate with a toothed ring that cooperates with the stop member, and a spring-preloaded locking pawl movably guided in the stop member can engage with the toothed ring against the spring force of a pre-tensioning spring, and the locking plate may be fixedly mounted to the frame.

[0036] In some embodiments, axially on a side of the locking plate facing away from the take-up spool, the seat belt retractor may include a vehicle sensing device that cooperates with the stop member.

[0037] In some embodiments, on the side of the take-up spool axially opposite the locking plate, the seatbelt retractor may include a support plate, which may be fixedly mounted to the frame and which may be used to support a torsion spring that pre-tensions the take-up spool in the webbing take-up direction so that the webbing is wound onto the take-up spool when not being worn by an occupant.

[0038] The above-mentioned technical features, the technical features to be mentioned below, and the technical features shown individually in the drawings may be combined with each other arbitrarily, as long as the combined technical features are not mutually contradictory. All technically feasible combinations of features are included in the technical content herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Exemplary embodiments of a seatbelt retractor according to the present invention will be described below with reference to the drawings. Among them:

[0040] Figure 1 is a longitudinal sectional view of a seatbelt retractor according to an embodiment of the present invention.

[0041] Figure 2 is Figure 1 a partially enlarged longitudinal sectional view of multiple components of the seatbelt retractor in an assembled state. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] Figure 1 is a longitudinal sectional view of a seatbelt retractor according to an embodiment of the present invention, and Figure 2 is Figure 1 a partially enlarged longitudinal sectional view of multiple components of the seatbelt retractor in an assembled state.

[0043] The seatbelt retractor may include a frame 1 configured to be mounted in a vehicle. The seatbelt retractor may be fixed, for example, to the vehicle body or the seat backrest by means of the frame 1. Typically, the frame 1 may be configured as a U-shaped frame including two legs and a bottom plate connecting the two legs, and each leg may have an opening through which the take-up spool 3 of the seatbelt retractor may be rotatably supported directly or indirectly.

[0044] The take-up spool 3 is for winding the flexible webbing 2 of the seatbelt device. On one axial end side of the take-up spool 3 ( Figure 1 the right end side thereof), there may be provided a support plate 5, which may be fixedly mounted to the frame 1. The support plate 5 may be used to support a torsion spring that pre-tensions the take-up spool 3 in the webbing take-up direction so that the webbing 2 is wound onto the take-up spool 3 when not being worn by an occupant. The torsion spring may be provided with an end cap 23 that may be fixed to the support plate 5 to cover the torsion spring. The support plate 5 has an opening 12 through which the take-up spool 3 may pass through the support plate 5.

[0045] The seat belt retractor may include a load limiting device, and the load limiting device may mainly include a load limiting member 4. The load limiting member 4 may be a load limiting rod, and one end 4b of the load limiting rod may be torsionally connected to the reel 3, in particular directly torsionally connected, and the other end 4a thereof may be directly torsionally connected to a drive wheel 6 which will be described in more detail below. For example, the load limiting member 4 may be a torsion bar with splines at both ends. The load limiting member 4 may be configured to fail when a predetermined load threshold is exceeded. For example, the load limiting member 4 may undergo plastic deformation when a predetermined torsional load threshold is exceeded, or alternatively be cut off, or alternatively the torsional connection between the load limiting member 4 and the reel 3 may be broken when a predetermined torsional load threshold is exceeded.

[0046] The seat belt retractor may include a pretensioning device 10, and the pretensioning device has the drive wheel 6 mentioned above, and the drive wheel is coupled to the reel 3 via the load limiting member 4. In the illustrated embodiment, the drive wheel 6 is configured as a ball gear, and the ball gear has teeth and ball sockets between the teeth. The pretensioning device 10 may include a gas generator 16 and a set of drive steel balls. The drive steel balls can be fired by the gas generated by the gas generator 16 when the gas generator 16 is triggered, and thus can be guided by the serpentine duct 17 to engage with the drive wheel 6 and drive the drive wheel 6, so that the reel 3 coupled to the drive wheel 6 via the load limiting member 4 rotates in the webbing retraction direction to pretension the webbing 2. The pretensioning device 10 may further have a ball accumulator 15, and through this ball accumulator, it is possible to prevent the spheres and the flame and debris generated by the gas generator 16 from being discharged into the interior space of the vehicle after the pretensioning device 10 is activated.

[0047] The seat belt retractor may include a lockable idler wheel 9. The drive wheel 6 may be torsionally connected to the idler wheel 9, in particular directly torsionally connected.

[0048] The drive wheel 6 may have a hub 6c on a first side facing the reel 3, and the reel 3 may have a stepped hole 20, and the hub 6c is rotatably supported in a hole section 20a with a larger diameter of the stepped hole 20 of the reel 3. Therefore, when observed axially, the drive wheel 6 partially overlaps with the reel 3. Between the drive wheel 6 and the reel 3, in addition to the torsional coupling via the load limiting member 4, the drive wheel 6 is rotatably supported relative to the reel 3 by means of the hub 6c in the hole section 20a of the stepped hole 20 of the reel 3.

[0049] The drive wheel 6 may have a central hole 18 which can receive a force-limiting member 4 and a stop wheel 9. The drive wheel 6 may have an axial first half 6a and a second half 6b, wherein the central hole 18 has a larger diameter in the first half 6a, i.e., the first hole section 18a, and a smaller diameter in the second half 6b, i.e., the second hole section 18b. In the central hole 18, a step, such as an annular stepped surface, is formed between the first half 6a and the second half 6b.

[0050] The stop wheel 9 may have a first shaft section 19a with a larger diameter, a second shaft section 19b with a smaller diameter, a first collar 21 at the end of the first shaft section 19a facing away from the second shaft section 19b, and a second collar 22 between the first shaft section 19a and the second shaft section 19b. The first shaft section 19a of the stop wheel 9 may be received in the first hole section 18a. The second shaft section 19b of the stop wheel 9 may be received in the second hole section 18b. The first collar 21 may abut against the drive wheel 6. The second collar 22 may abut against the step of the central hole 18. The stop wheel 9 may be directly torsionally connected to the drive wheel 6 in the first hole section 18a and the second hole section 18b of the central hole 18 by a segmented spline in the first shaft section 19a and the second shaft section 19b. The force-limiting member 4 extends with its end 4a into the second hole section 18b. In the second hole section 18b of the central hole 18 of the drive wheel 6, the stop wheel 9 and the force-limiting member 4 may abut against each other or be adjacent to each other with their end faces.

[0051] The seat belt retractor may include a locking plate 7. The locking plate 7 may be fixedly mounted to the frame 1. The locking plate 7 has an opening 11 so that the stop wheel 9 can pass through the locking plate 7. The locking plate 7 may axially fix the stop wheel 9 and may cooperate with the stop wheel 9. For example, the stop wheel 9 may have a chute in which a spring-preloaded locking pawl 8 is movably guided, and the locking plate 7 may have a toothed ring 13. The locking pawl 8 is held disengaged from the toothed ring 13 of the locking plate 7 under the spring force of the preloading spring, and engages with the toothed ring 13 and thus locks the stop wheel 9 when overcoming the spring force of the preloading spring. The structural unit including the reel 3, the force-limiting member 4, the drive wheel 6, and the stop wheel 9 may be directly or indirectly supported rotatably relative to the frame 1 through the openings of the frame 1 and / or the openings 12 of the support plate 5 and / or the opening 11 of the locking plate 7. For example, the reel 3 may be indirectly supported rotatably relative to the frame 1 through the openings 11, 12.

[0052] Axially on the side of the locking plate 7 facing away from the webbing spool 3, the seat belt retractor may include a vehicle sensing device 14 that cooperates with the locking wheel 9. The vehicle sensing device 14 may sense safety-related states of the motor vehicle, such as vehicle acceleration and vehicle tilt angle, and may cause the locking of the locking wheel 9 when the vehicle acceleration or vehicle tilt angle exceeds a corresponding threshold, and thereby the webbing spool 3 is locked in the webbing pulling-out direction, so that the webbing 2 cannot continue to unwind or be pulled out from the webbing spool 3. The locking wheel 9 may also cooperate with a webbing sensing device, wherein the too-fast pulling out of the webbing 2 from the seat belt retractor may cause the locking of the locking wheel 9. The vehicle sensing device 14 may be provided with an end cap 24, which may be connected to the locking plate 7 to cover the vehicle sensing device 14.

[0053] Compared with the seat belt retractor known from the prior art, in the embodiment of the seat belt retractor according to the invention shown in the figure, the pretensioning device 10 does not act directly on the webbing spool 3, wherein the ball gear is only connected to the webbing spool 3 through a force-limiting rod. In an emergency situation of the vehicle, during the force-limiting process immediately following the pretensioning process, the pretensioning device has basically no influence on the force-limiting function. A substantially stable shoulder belt force can be generated on the webbing 2 when the force-limiting device is in operation. In addition, such a seat belt retractor is structurally compact, has a small number of parts, and is easy to manufacture and assemble.

[0054] It should be noted that the terms used herein are for the purpose of describing specific aspects only and are not intended to limit the disclosure. As used herein, the singular forms "a" and "the one" shall include the plural forms unless the context clearly dictates otherwise. It can be understood that the terms "comprising" and "including" and other similar terms, when used in the application documents, specify the presence of the stated operations, elements, and / or components, without excluding the presence or addition of one or more other operations, elements, components, and / or combinations thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. In the description of the drawings, like reference numerals always denote like elements.

[0055] The thickness of the elements in the drawings may be exaggerated for clarity. It is also understood that if an element is said to be on another element, coupled to another element, or connected to another element, then the said one element may be formed directly on, coupled to, or connected to the other element, or there may be one or more intermediate elements therebetween. Conversely, if the expressions "directly on", "directly coupled to", and "directly connected to" are used herein, then it means there are no intermediate elements. Other words used to describe the relationship between elements should be interpreted similarly, such as "between" and "directly between", "attached" and "directly attached", "adjacent" and "directly adjacent", etc.

[0056] It is understood that although terms such as "first", "second", etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element may be referred to as a second element without departing from the teachings of the inventive concept.

[0057] Finally, it should be noted that the above embodiments are only for understanding the present invention and do not limit the protection scope of the present invention. For those skilled in the art, modifications can be made on the basis of the above embodiments, and these modifications do not depart from the protection scope of the present invention.

Claims

1. A seat belt retractor, comprising: A spool (3) rotatably supported for winding a webbing; A force limiter (4) configured to fail when a predetermined load threshold is exceeded; A pretensioning device (10) having a drive wheel (6) coupled to the spool via the force limiter, the drive wheel being drivable such that the spool coupled to the drive wheel rotates in the webbing winding direction to pretension the webbing; And A lockable stop member; Characterized in that the drive wheel (6) is directly torsionally connected to the force limiter (4) on a first side facing the spool, and the drive wheel is rotatably supported relative to the spool, in addition to the torsional coupling between the drive wheel and the spool via the force limiter; The drive wheel (6) is directly torsionally connected to the stop member on a second side facing away from the spool; The drive wheel (6) has a central hole (18) that receives the force limiter on a first side facing the spool and receives the stop member on a second side facing away from the spool.

2. The seat belt retractor according to claim 1, characterized in that, The drive wheel is a gear or a friction wheel.

3. The seat belt retractor according to claim 1 or 2, characterized in that, The stop member is a stop wheel (9).

4. The seat belt retractor according to claim 1 or 2, characterized in that, The force limiter (4) is a force limiting rod that is directly torsionally connected to the spool (3) at one end (4b) thereof and directly torsionally connected to the drive wheel (6) at the other end (4a) thereof.

5. The seat belt retractor according to claim 1 or 2, characterized in that, The central hole (18) is configured as a stepped hole having a first hole section (18a) with a larger diameter, a second hole section (18b) with a smaller diameter, and a step between the first hole section and the second hole section; The stop member has a first shaft section (19a) with a larger diameter, a second shaft section (19b) with a smaller diameter, a first shoulder (21) at an end of the first shaft section facing away from the second shaft section, and a second shoulder (22) between the first shaft section and the second shaft section; Wherein the first shaft section of the stop member is received in the first hole section, the second shaft section of the stop member is received in the second hole section, the first shoulder abuts against the drive wheel, the second shoulder abuts against the step of the central hole, and the second hole section also receives the force limiter.

6. The seat belt retractor according to claim 5, wherein, The stop member is directly torsionally connected to the drive wheel (6) in the first hole section and the second hole section of the central hole by a segmented spline in the first shaft section and the second shaft section, and the force limiter (4) is directly torsionally connected to the drive wheel by a spline in the second hole section of the central hole.

7. The seat belt retractor according to claim 5, characterized in that, The stop member and the force limiter (4) are in contact with each other or adjacent to each other in the second hole section of the central hole.

8. The seat belt retractor according to claim 1 or 2, characterized in that, The drive wheel (6) has a hub portion (6c) on a first side facing the spool, and the spool (3) has a stepped hole (20), and the hub portion is rotatably supported in a hole section (20a) with a larger diameter of the stepped hole of the spool.

9. The seat belt retractor according to claim 1 or 2, characterized in that, The drive wheel (6) is configured as a ball gear, which has teeth and ball sockets between the teeth. The pre-tensioning device (10) includes a gas generator (16) and a set of drive balls, which can be triggered by the gas generated by the gas generator when the gas generator is triggered, and can thus engage with the ball gear and drive the ball gear.

10. The seat belt retractor according to claim 1 or 2, characterized in that, The seat belt retractor includes a frame (1), which is configured for installation in a vehicle, and a structural unit including a webbing reel, a force limiter, a drive wheel, and a stop member is rotatably supported in the frame.

11. The seat belt retractor according to claim 10, characterized in that, The seat belt retractor includes a locking plate (7) having a toothed ring (13) that cooperates with the stop member. A spring-preloaded locking pawl (8) that is movably guided in the stop member can engage with the toothed ring against the spring force of the pre-tensioning spring. The locking plate is fixedly mounted to the frame.

12. The seat belt retractor according to claim 1 or 2, characterized in that, The seat belt retractor has a vehicle sensing device (14) and / or a webbing sensing device that cooperate with the stop member.

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