A seat belt retractor and pretensioning assembly

Abstract

The application provides a seat belt retractor and a pretensioning assembly, and belongs to the technical field of seat belt pretensioning, wherein the pretensioning assembly comprises a reel, a pretensioning gear disc and a force limiting rod, the reel is additionally provided with an outer convex circle, the first end of the pretensioning gear disc is embedded and installed in the inner part of the outer convex circle of the reel, the pretensioning gear disc and the reel are supported with each other to reduce the error of coaxiality between the pretensioning gear disc and the reel, the force limiting rod is inserted into the inner part of the reel, one end of the force limiting rod is fixedly connected with the first end of the reel, and the other end of the force limiting rod is fixedly connected with the pretensioning gear disc, so that after the first end of the pretensioning gear disc is embedded and installed in the reel, the height of the outer convex circle on the second end of the reel and the height of the second end of the pretensioning gear disc are both higher than the height of the radial teeth, so that the radial teeth can drive the pretensioning gear disc to rotate after receiving the driving force provided by the pretensioning rod in the seat belt retractor, and then the reel is driven by the force limiting rod to rotate and wind the seat belt.

Description

Technical Field

[0001] The present application relates to the technical field of seat belt pre-tensioning, and in particular to a seat belt retractor and a pre-tensioning assembly. Background Art

[0002] Currently, the pretensioning assembly in a seatbelt retractor typically consists of two to four components: a locking flange, a pretensioning gear, a pressure plate, and a force-limiting rod. The pretensioning mode is achieved by the driving force of a dynamite explosion, with torque being applied to the force-limiting rod in the pretensioning assembly. However, due to the limitations of existing pretensioning structures, the driving force of the dynamite explosion causes the force-limiting rod in the pretensioning assembly to rotate out of sync with the reel's speed. The inertia of the force-limiting rod causes it to deform during rapid rotation, impacting the efficiency of the dynamite pretensioning webbing.

[0003] Based on this, a new technical solution for pre-tensioning components is needed. Summary of the Invention

[0004] In view of this, the present application provides a seat belt retractor and a pre-tensioning assembly to quickly and stably respond to the pre-tensioning function, thereby pre-tensioning the seat belt in time when a collision occurs to prevent passengers from being injured.

[0005] This application provides the following technical solutions:

[0006] The present application provides a pre-tensioning assembly for a seat belt retractor, comprising:

[0007] A reel for reeling up a safety belt, wherein a first bearing portion is provided on the outside of the first end of the reel for the reel to be rotatably connected in the retractor; an outer convex circle is provided on the second end of the reel; and a hollow portion is provided in the axial direction of the reel;

[0008] A pre-tensioning gear plate for receiving a driving force provided by a seat belt retractor and rotating, wherein the first end of the pre-tensioning gear plate is embedded in the inner part of an outer convex circle mounted on the second end of the spool, so that the pre-tensioning gear plate and the spool support each other to reduce the coaxiality error between the pre-tensioning gear plate and the spool; a second bearing portion is provided on the outer side of the second end of the pre-tensioning gear plate for the pre-tensioning gear plate to be rotatably connected in the retractor; a plurality of radial teeth are provided between the two ends of the pre-tensioning gear plate;

[0009] A force limiting rod is provided axially between the reel and the pre-tightening gear plate, wherein the force limiting rod penetrates into the interior of the reel, and one end of the force limiting rod is fixedly connected to the first end of the reel, and the other end of the force limiting rod is fixedly connected to the pre-tightening gear plate;

[0010] Among them, after the first end of the pre-tensioning gear plate is embedded and installed on the reel, the height of the outer convex circle on the second end of the reel and the height of the second end of the pre-tensioning gear plate are both higher than the radial teeth, so that the radial teeth can be used to receive the driving force provided by the pre-tensioning rod in the seat belt retractor and drive the pre-tensioning gear plate to rotate, and then the force limiting rod drives the reel to rotate and rewind the seat belt.

[0011] Preferably, the tooth tips of the radial teeth are configured as convex tooth top structures, and the maximum height of the convex tooth top structure is higher than the height of the first end of the preload gear plate.

[0012] Preferably, the convex tooth top structure of the radial teeth partially follows the first end of the pre-tightening gear plate and is embedded in the outer convex circle on the second end of the winding shaft.

[0013] Preferably, the radial teeth are provided with the convex tooth top structure so as to have an impact strength 10%-30% higher than that of the radial teeth with a straight tooth top structure.

[0014] Preferably, a ratchet structure with a one-way ratchet is provided in the outer convex circle on the second end of the reel, and a plurality of radial protrusions arranged at intervals are provided on the outer peripheral surface of the first end of the pre-tightening gear plate. The ratchet structure is used to cooperate with the radial protrusion structure, so that when the pre-tightening gear plate rotates forward after the radial teeth are driven by driving force, the force limiting rod and the reel are synchronously driven to rotate, and when the pre-tightening gear plate rotates reversely after the radial teeth lose driving force, the pre-tightening gear plate is disengaged from the reel to reduce the force limiting fluctuation.

[0015] Preferably, the preload gear plate is fixedly connected to the force-limiting rod through an integral plastic-wrapped structure.

[0016] Preferably, a plurality of holes are arranged on the end face of the second end of the pre-tightening gear plate, and the holes are used for integrally wrapping and fixing the pre-tightening gear plate and the force limiting rod, and for facilitating the mold ejector to push the end face of the force limiting rod to be demolded after the wrapping and fixing.

[0017] Preferably, the preload gear plate is made of high-strength polymer injection molding or metal mixture die casting.

[0018] Preferably, the first end of the force-limiting rod is provided with a first spline, and the first end of the force-limiting rod and the first end of the reel are fixedly connected by interference fitting with the first spline;

[0019] And / or, the second end of the force limiting rod is provided with a second spline, and the second end of the force limiting rod is fixedly connected to the preload gear plate via the second spline;

[0020] And / or, the force limiting rod is a metal force limiting rod.

[0021] The present application also provides a seat belt retractor, comprising a pre-tensioning assembly of the seat belt retractor as described in any one of the embodiments of the present application.

[0022] Compared with the prior art, the at least one technical solution adopted in this application can achieve the following beneficial effects:

[0023] By improving the interconnection structure between the reel and the pretensioning gear plate, that is, adding an outer convex circle structure at one end of the reel, and removing the convex circle at one end of the pretensioning gear plate and improving it to be embedded and installed inside the outer convex circle structure added to the reel, stable and reliable mutual support between the reel and the pretensioning gear plate is achieved, thereby improving the coaxiality error of the pretensioning assembly, and improving the force and torque transmission of the force limiting rod. This can ensure that the reel, pretensioning gear plate and force limiting rod rotate synchronously, and can avoid the force limiting rod from being easily deformed during the torque transmission in response to the pretensioning function, thereby affecting the force and torque transmission. This ensures that the pretensioning assembly can quickly respond to the pretensioning function, and in responding to the pretensioning function, it can avoid the force limiting causing harm to the occupants using the seat belts. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 is a schematic structural diagram of a retractor assembly including a pretensioner in the present application;

[0026] Figure 2 It is a schematic diagram of the partial structure of the retractor assembly in this application;

[0027] Figure 3 It is a partial cross-sectional structural diagram of the pre-tensioning component of the retractor assembly in this application;

[0028] Figure 4 It is a schematic diagram of the exploded structure of the pre-tensioning component of the retractor assembly in this application;

[0029] Figure 5 is a schematic diagram of an exploded view and a cross-sectional view of the pre-tensioning assembly in this application;

[0030] Figure 6 is a schematic diagram of an exploded view and a cross-sectional view of the pre-tensioning assembly in this application;

[0031] Figure 7 It is a schematic diagram of the assembly and cross-section of the pre-tensioning gear plate and the force-limiting rod of the pre-tensioning assembly in this application;

[0032] Figure 8It is a cross-sectional schematic diagram of the additional holes in the plastic-coated structure of the pre-tensioning gear plate and the force-limiting rod of the pre-tensioning assembly in this application.

[0033] Explanation of the reference numerals: seat belt 10; retractor 20; gas generator 21; pretensioning pipeline 22; cover 23; mounting frame 24; pretensioning assembly 25; reel 251; outer convex circle 2511; ratchet structure 2512; pretensioning gear plate 252; radial teeth 2521; ratchet 2522; non-convex structure 2523; convex structure 2524; hole 2525; force limiting rod 253. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0036] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0037] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0038] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0039] refer to Figures 1 to 3 As shown in the figure, the seat belt includes a seat belt 10 and a retractor 20 (i.e., a retractor including a pretensioning component), wherein the retractor 20 includes a gas generator 21, a pretensioning pipeline 22 providing driving force (usually a pretensioning rod is arranged inside the pretensioning pipeline), left and right side covers 23, a mounting frame 24 and a pretensioning component 25 as a core component.

[0040] In the pretensioner assembly, the tensioner is operably connected to the reel assembly, and when the initial stage of a vehicle collision is detected, the pretensioner is activated to drive the reel to rotate, retracting the seat belt webbing into the retractor, reducing the gap between the occupant and the webbing, so as to reduce the forward movement or deviation of the occupant during a collision or deceleration.

[0041] The tensioner consists of a steel tube connected to a gas generator and a pretensioning rod (also called a pretensioning rod) placed within it. When the pretensioner system interacts with the gas generator, an electrical signal is sent to the gas generator, generating a large amount of high-pressure gas. This high-pressure gas pushes the pretensioning rod inside the steel tube, causing it to engage with the gear plate of the pretensioning force-limiting rod assembly. This translates the pretensioning rod's movement into rotation of the gear plate, which in turn drives the spool. Typically, a gunpowder tensioning mode is used, with the gunpowder driving the pretensioning rod. The engagement between the pretensioning rod and the pretensioning assembly causes the pretensioning assembly to rotate the seatbelt, pre-tensioning the seatbelt in the event of a collision.

[0042] In the above structure, as the core component of the pretensioner, the pretensioning assembly can generally be composed of gears, force transmission rods (force limiting rods) and reels, and these parts are generally separate parts, which require fixed connection and torque transmission based on the mounting structure between each other.

[0043] In view of this, during the research and improvement exploration of the seat belt retractor and pretensioner assembly, it was found that the existing retractor solution has the following deficiencies:

[0044] On the one hand, the existing interconnection structure within the pretensioning assembly results in large coaxiality errors, which easily affect torque transmission efficiency. Each component has its own axial properties, so after the components are assembled, the coaxiality of the assembly has a significant impact on torque transmission. For example, large coaxiality errors between the torque limiter and the spool affect torque transmission. Torque transmission, in turn, affects pretensioning efficiency.

[0045] Secondly, the interconnection structure scheme inside the existing pre-tensioning assembly also affects the synchronization between the rotation speed of the force limiter and the rotation speed of the reel. At this time, the inertia of the forward rotation will cause the force limiter to deform during rapid rotation. The deformation of the force limiter will lead to a decrease in the efficiency of the seat belt gunpowder pre-tensioning webbing, and even a decrease in safety and reliability.

[0046] Thirdly, the interconnection structure scheme inside the existing pre-tensioning assembly has a significant force limit fluctuation in the later stage of pre-tensioning because the tension of the seat belt reacts to the reel after positive tensioning, further affecting the pre-tensioning effect and even causing deformation of the force limit rod. Excessive force limit fluctuations can easily cause harm to passengers using the seat belt.

[0047] In summary, due to the limitations of the interconnected structure of components in existing pre-tensioning assemblies, the coaxiality accuracy is not high, which affects the pre-tensioning effect and efficiency of the retractor, and even causes adverse effects such as easy deformation of the force limiter and large fluctuations in the force limit.

[0048] Based on this, the present application provides a new solution for the pre-tensioning assembly of a seat belt retractor: Figures 4 to 8 As shown, the pre-tensioning assembly may include components such as a reel 251, a force-limiting rod 253 and a pre-tensioning gear plate 252, and a new improved design is made for the connection structure between these components, so that a connection structure with more efficient torque transmission and more stable rotation is achieved through the improved and optimized reel 251, the force-limiting rod 253 and the pre-tensioning gear plate 252, thereby improving the coaxiality of the entire pre-tensioning assembly, making the rotation of the pre-tensioning assembly smoother, the torque transmission efficiency higher, and protecting the force-limiting rod from being easily deformed during rotation.

[0049] Compared with the existing pre-tensioning component solution, the improvements are as follows:

[0050] On the one hand, regarding the interconnection structure between the spool 251 and the preload gear plate 252, an outer convex circle 2511 is added to the spool 251, and the original convex portion is removed from one end of the preload gear plate 252, so that the end of the preload gear plate without the convex circle can be embedded and installed inside the outer convex circle 2511. Because the outer convex circle 2511 and the preload gear plate are both circular, and the embedded installation method ensures stable mutual support between the preload gear plate and the spool, it can reduce the coaxiality error between the preload gear plate, the force limiting rod, and the spool. In this way, the torque transmission is less affected, and the rotation effect is improved.

[0051] It should be noted that, see Figure 5 Although the original convex part is removed from one end of the preload gear plate 252 and designed as Figure 5The non-convex structure 2523 is shown, but in the structure after the reel 251 and the pre-tightening gear plate 252 are interconnected, since the reel 251 is additionally provided with an outer convex circle 2511, the outer convex circle 2511 added to the reel 251 and the convex structure 2524 still retained in the pre-tightening gear plate 252 can still be used to jointly form a radial tooth 2521 (see Figure 3 A cavity is formed between the two sides of the gear (schematically shown as a diagram of the gear meshing with the preload rod), which can provide an accommodating space for the radial teeth 2521 to mesh with the preload rod, thereby ensuring that the radial teeth 2521 and the preload rod can mesh stably and reliably.

[0052] Secondly, with respect to the structure in which both ends of the force limiting rod 253 are connected to the reel 251 and the pre-tightening gear plate respectively, one end face of the force limiting rod 253 is inserted into the pre-tightening gear plate 252 to achieve a fixed connection, and the other end face of the force limiting rod 253 is inserted into the reel 251 to achieve a fixed connection. Therefore, after the force limiting rod 253 is respectively inserted into the reel 251 and the pre-tightening gear plate 252 and a fixed connection is achieved, that is, the force limiting rod 253 can provide preliminary support for the reel 251 and the pre-tightening gear plate 252, the above-mentioned reel 251 and the pre-tightening gear plate 252 are combined to achieve mutual stable support through the outer convex circle 2511. Under the two supports, the reel 251, the force limiting rod 253 and the pre-tightening gear plate 252 have direct and stable support for each other, further improving the coaxiality error, and the torque generated by the pre-tightening gear plate 252 under the drive of the pre-tightening rod is more effectively transmitted to the reel 251 through the force limiting rod 253, and the transmission process is very stable and reliable, which can achieve the synchronous rotation of the reel 251, the force limiting rod 253 and the pre-tightening gear plate 252.

[0053] The following describes the technical solutions provided by various embodiments of the present application in conjunction with the accompanying drawings.

[0054] like Figures 4 to 8 As shown, the present application provides a pretensioning assembly for a seatbelt retractor, comprising: a spool 251, a force-limiting rod 253, and a pretensioning gear plate 252. The spool 251 is used to reel the seatbelt; the pretensioning gear plate 252 is used to rotate by receiving the driving force provided by the seatbelt retractor; and the force-limiting rod 253, disposed axially between the spool 251 and the pretensioning gear plate 252, is used to transmit the torque generated by the rotation of the pretensioning gear plate 252 to the spool 251. Under the torque transmitted by the force-limiting rod 253, the spool 251, the force-limiting rod 253, and the pretensioning gear plate 252 can rotate synchronously.

[0055] In practice, the structural design of the reel 251, the force limiting rod 253 and the pre-tightening gear plate 252 to achieve synchronous rotation is shown as follows:

[0056] In the structural design of the reel 251, a first bearing portion is provided on the outside of the first end of the reel 251 for the reel to be rotatably connected in the reel, an outer convex circle 2511 is provided on the second end of the reel 251, and the reel 251 is provided with a hollow portion along the axial direction.

[0057] In the structural design of the pre-tensioning gear plate 252, the first end of the pre-tensioning gear plate 252 is no longer designed as a convex circle, but is designed as a non-convex structure 2523 that can be embedded in the outer convex circle 2511 installed on the second end of the reel 251, so that the reel 251 and the pre-tensioning gear plate 252 can stably support each other, thereby improving the coaxiality error between the pre-tensioning gear plate and the reel; the second end of the pre-tensioning gear plate 252 is designed as a convex structure 2524, and a plurality of radial teeth 2521 for receiving the driving force of the reel (such as engaging with the pre-tensioning rod) are arranged between the first end and the second end, and a second bearing portion is arranged outside the second end of the pre-tensioning gear plate 252 for the pre-tensioning gear plate to be rotatably connected in the reel. During implementation, when designing the structure of the pre-tightening gear plate 252, the structure similar to that of the traditional pre-tightening gear plate can be retained, and only the first end of the pre-tightening gear plate 252 used for interconnection with the reel 251 can be improved to a structural form that can be embedded in the non-convex structure 2523 inside the outer convex circle 2511 installed on the second end of the reel 251. At this time, the convex structure 2524 and the outer convex circle 2511 of the reel 251 can still be used to provide accommodation space for the radial teeth 2521 to receive the retractor driving force (such as engaging the pre-tightening rod).

[0058] In the structural design of the force limiting rod 252, after the two ends of the force limiting rod 253 are respectively inserted into the reel 251 and the pre-tightening gear plate 252, the force limiting rod 253 is fixedly connected to the reel 251 and the pre-tightening gear plate 252 respectively. Combined with the mutually supporting structure between the reel 251 and the pre-tightening gear plate 252, the force limiting rod 253 more stably supports the reel 251 and the pre-tightening gear plate 252, so that the reel 251 and the pre-tightening gear plate 252 and the force limiting rod 253 also stably support each other, further improving the coaxiality error between the pre-tightening gear plate and the reel, and realizing good force and torque transmission of the force limiting rod 253.

[0059] During implementation, the interconnected structure of the reel 251, the limiting rod 253 and the pre-tensioning gear plate 252 for achieving synchronous rotation is schematically shown as follows: the first end of the limiting rod 253 penetrates into the interior of the reel 251, and one end of the limiting rod 253 is fixedly connected to the first end of the reel 251, and the other end of the limiting rod 253 is embedded in the pre-tensioning gear plate and fixedly connected; and, after the first end of the pre-tensioning gear plate 252 is embedded and installed on the outer convex circle 2511 of the reel 251, the height of the outer convex circle 2511 on the second end of the reel 251 and the height of the second end of the pre-tensioning gear plate 252 are both higher than the radial teeth 2521, so that the radial teeth 2521 can be used to receive the driving force provided by the pre-tensioning rod in the seat belt retractor and drive the pre-tensioning gear plate 252 to rotate, and then the limiting rod 253 drives the reel 251 to rotate and rewind the seat belt.

[0060] It should be noted that the first bearing portion for the reel 251 to be freely rotatably connected in the reel and the second bearing portion for the pre-tensioning gear plate 252 to be freely rotatably connected in the reel can refer to the existing structural design and are not limited here.

[0061] By arranging a special annular outer convex circle 2511 on the reel 251, the outer convex circle 2511 can be used to provide additional support for the pre-tightening gear plate 252 in the reel 251, thereby improving the rotational stability of the pre-tightening gear plate 252 in the reel 251 and increasing the bearing strength of the reel 251, thereby improving the pre-tightening effect and the reliability of the pre-tensioning assembly.

[0062] In some embodiments, the force limiting rod 253 can be designed as a dumbbell structure, and the two ends of the dumbbell structure can be used to more stably achieve a fixed connection between the reel 251, the pre-tightening gear plate 252 and the force limiting rod 253, and the two ends of the dumbbell structure can be used to make the force limiting rod 253 more stably carry the reel 251 and the pre-tightening gear plate 252, thereby achieving better load-bearing and torque transmission of the force limiting rod 253.

[0063] In some embodiments, the tooth tips of the radial teeth in the gear plate can generally be a flat-top structure. In the present application, the design can be improved to a convex tooth top structure, and the maximum height of the convex tooth top structure is slightly higher than the height of the first end of the pre-tightening gear plate 252, that is, in the pre-tightening gear plate 252, the maximum height of the convex tooth top structure of the radial teeth 2521 is slightly higher than the height of the non-convex structure 2523 on the first end of the pre-tightening gear plate 252, and is much lower than the height of the convex structure 2524 on the second end of the pre-tightening gear plate 252. For specific structural forms, please refer to Figure 7 The enlarged view of the part in center C is shown.

[0064] In practice, the radius R of the convex tooth top structure may be designed to meet the matching between the maximum height of the tooth tip and the first end height and the second end height of the preload gear plate 252 , so that the radial teeth can better receive the retractor driving force.

[0065] In some embodiments, by selecting an appropriate radius R, such as a maximum tooth tip height that is slightly higher than the first end height of the preload gear plate 252 by 1-5 mm, the radial teeth of the convex tooth top structure can have a 10%-30% higher impact strength than radial teeth of a straight tooth top structure. It should be noted that the radial teeth of the present application, by designing the radial teeth with a convex tooth top structure, can have a 10%-30% higher impact strength than radial teeth of a straight tooth top structure. Therefore, the radius R can be specifically set according to the impact strength requirements and is not limited here.

[0066] By improving the tooth tip of the radial tooth 2521 into a convex tooth top structure, compared with the straight convex tooth top structure, the present application can utilize the convex tooth top structure to carry higher external loads, thereby improving the gear plate's ability to bear external load impact, ensuring that the gear plate has higher impact resistance, and helping to improve the reliability and durability of the pretensioning assembly.

[0067] In some embodiments, the convex tooth top structure of the radial tooth 2521 partially follows the first end of the pre-tightening gear plate 252 and is embedded in the outer convex circle 2511 on the second end of the reel 251, and the convex tooth top structure is further utilized to achieve good support between the pre-tightening gear plate 252 and the reel 251, further improve the coaxiality, and further reduce the axial force on the limit rod 253, so that the limit rod 253 can better transmit torque and is not easily deformed, thereby improving the performance and reliability of the limit rod 253.

[0068] In some embodiments, after the outer convex circle 2511 is added to the reel 251, the internal structure of the outer convex circle 2511 can be utilized, such as arranging a special ratchet structure inside the outer convex circle 2511, so as to utilize the characteristics of the ratchet structure to improve the support and installation performance between the reel 251 and the pre-tensioning gear plate 252, and also improve the pre-tensioning response effect.

[0069] During implementation, a one-way ratchet structure 2512 is added to the inside of the outer convex circle 2511 on the second end of the reel 251, and a number of radial protrusions arranged at intervals are provided on the outer peripheral surface of the first end of the pre-tightening gear plate 252, that is, radial protrusions arranged at intervals are added to the non-convex circle structure 2523 of the pre-tightening gear plate 252, so that the ratchet structure 2512 can achieve a tight structural fit with the radial protrusions.

[0070] With the ratchet structure 2512 and the radial protrusion structure cooperating, when the preload gear plate 252 rotates forward (e.g., clockwise) after receiving a driving force from the radial teeth 2521, it can quickly and synchronously drive the force limiting rod 253 and the spool 251 to rotate, thereby improving system response and avoiding a decrease in system response (e.g., the rotation start speed of the spool 251) due to the rotation of the force limiting rod 253. In addition, when the preload gear plate 252 rotates backward (e.g., counterclockwise) after losing the driving force from the radial teeth 2521, the preload gear plate 252 and the spool 251 can be easily disengaged, thereby reducing or even preventing force limiting fluctuations and further improving the force and torque transmission effect of the force limiting rod 253.

[0071] In some embodiments, the preload gear plate 252 of the present application may be a gear component molded from high-strength plastic, so that a one-piece gear plate can be manufactured in an integrated manner using a plastic molding process.

[0072] refer to Figure 8 As shown in the figure, the pre-tightening gear plate 252 is fixedly connected to the force limiting rod 253 through an integrated plastic-coated structure, that is, the fixing method of the pre-tightening gear plate 252 and the force limiting rod 253 is a special plastic-coated structure combination, and one end face of the force limiting rod 253 is inserted into the gear center line of the pre-tightening gear plate 252 in the plastic-coated structure. The pre-tightening gear plate 252 and the force limiting rod 253 of a single structure are integrated through the plastic-coated structure, that is, compared with the traditional solution that requires the use of multiple separate parts, such as a separate part assembly structure in which the gear plate is composed of three parts and the force limiting rod is composed of one part, the present application can achieve a four-in-one integrated design of these parts, that is, the pre-tightening gear plate 252 and the force limiting rod 253 are integrated and designed as a single part, and after using the plastic-coated process, the assembly of the pre-tightening gear plate 252 and the force limiting rod 253 is simplified, and the coaxiality between the pre-tightening gear plate 252 and the force limiting rod 253 is improved, further reducing the coaxiality error between the internal parts of the pretensioning assembly, which is more conducive to the torque transmission of the force limiting rod 253.

[0073] In some examples, in the overmolded structure, the force limiting rod 253 is embedded in the structure of the preload gear plate 252, see Figure 8 As shown in the figure, the force limiting rod 253 can be more stably rotated by ensuring that the size B is larger than the size A.

[0074] In some examples, the material of the gear plate can be made of special high-strength polymer injection molding or metal mixture die-casting, that is, the pre-tightening gear plate is made of high-strength polymer injection molding or metal mixture die-casting, which further simplifies the design and production of the overmolded structure and is also beneficial to improving the reliability and durability of the gear plate.

[0075] In some examples, while meeting the requirements of the overmolding process, multiple holes can be arranged on the end face of the gear plate. In addition to ensuring the overmolding process between the pre-tightening gear plate 252 and the force limiting rod 253, these hole structures also facilitate demolding. That is, during demolding, the mold ejector can be directly pushed to the force limiting rod through the hole structure to avoid damaging the end face of the gear plate, ensuring that the overmolding process does not damage the gear plate, and is beneficial to improving the reliability and durability of the gear plate during use.

[0076] refer to Figure 8 As shown in the figure, a plurality of holes 2525 are arranged on the end face of the second end of the pre-tightening gear plate 252. The holes 2525 can be used for the plastic-wrapped fixed connection between the pre-tightening gear plate 252 and the force-limiting rod 253, and for facilitating the mold ejector to push the end face of the force-limiting rod 253 to complete demolding after the plastic-wrapped fixed connection.

[0077] In some embodiments, a spline connection method can be used, so as to take advantage of the excellent characteristics of the spline, such as the spline connection can bear force evenly, the total contact area is large and can withstand large loads, the guidance and centering are good during assembly, the centering accuracy is high, and the torque transmission is large, etc., to achieve a fixed connection structure between the force limiting rod 253 and the reel 251 and the pre-tightening gear plate 252 respectively, further reduce the coaxiality error, and improve the force and torque transmission.

[0078] In one example, see Figure 5 As shown in the figure, the first end of the force limiting rod 253 is provided with a first spline, so that the first end of the force limiting rod 253 and the first end of the reel 251 are fixedly connected by the first spline, wherein the fixed connection is a fixed connection structure after interference fit, so that the connection between the force limiting rod 253 and the reel 251 is more reliable, and the force limiting rod 253 is more stable and reliable when transmitting torque to the reel 251.

[0079] In one example, similar to the fixed connection between the force-limiting rod 253 and the spool 251, a second spline is provided on the second end of the force-limiting rod 253, thereby fixedly connecting the second end of the force-limiting rod 253 to the preload gear plate 252 via the second spline. It should be noted that in the aforementioned integrated plastic-coated structure of the preload gear plate 252 and the force-limiting rod 253, a spline structure can also be utilized to achieve a better plastic-coated structure, allowing the force-limiting rod 253 to be more stably and reliably plastic-coated within the preload gear plate 252.

[0080] In some embodiments, the force limiting rod is a metal force limiting rod. The metal force limiting rod is less likely to deform during the rapid response to preload rotation and more stably transmits the torque generated by the preload gear plate 252 to the reel 251. In addition, after using the metal force limiting rod, the integrated plastic-coated structure of the above example is simpler and more stable and reliable.

[0081] Based on the same inventive concept, this application also provides a seat belt retractor based on the pre-tensioning assembly provided in the above example. Figures 1 to 8 As shown in the structural diagram, the pre-tightening gear plate 252 can engage with the structure (such as a pre-tightening rod, which can also be called a pre-tightening rod, etc.) that provides driving force for the pre-tightening pipeline 22 of the retractor, and the pre-tightening gear plate 252 can be fixed by the ratchet 2522 and the mounting frame 24, and the reel 251 and the pre-tightening gear plate 252 are respectively connected to the bearings of the left and right side covers 23 through their respective bearing parts to achieve free rotation connection.

[0082] It should be noted that this application is an improved design for the pre-tensioning component 25, so the interconnection and interaction between the pre-tensioning component 25 and other internal structures of the retractor can be designed with reference to the existing retractor, without specific limitations or detailed explanations.

[0083] In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts can be referred to the partial description of the previous embodiments.

[0084] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A pre-tensioning assembly for a seat belt retractor, characterized in that: include: A reel for reeling up a safety belt, wherein a first bearing portion is provided on the outside of the first end of the reel for the reel to be rotatably connected in the retractor; an outer convex circle is provided on the second end of the reel; and a hollow portion is provided in the axial direction of the reel; A pre-tensioning gear plate for receiving a driving force provided by a seat belt retractor and rotating, wherein the first end of the pre-tensioning gear plate is embedded in the inner part of an outer convex circle mounted on the second end of the spool, so that the pre-tensioning gear plate and the spool support each other to reduce the coaxiality error between the pre-tensioning gear plate and the spool; a second bearing portion is provided on the outer side of the second end of the pre-tensioning gear plate for the pre-tensioning gear plate to be rotatably connected in the retractor; a plurality of radial teeth are provided between the two ends of the pre-tensioning gear plate; A force limiting rod is provided axially between the reel and the pre-tightening gear plate, wherein the force limiting rod penetrates into the interior of the reel, and one end of the force limiting rod is fixedly connected to the first end of the reel, and the other end of the force limiting rod is fixedly connected to the pre-tightening gear plate; wherein, after the first end of the pre-tensioning gear disc is embedded in and mounted on the reel, the height of the outer convex circle on the second end of the reel and the height of the second end of the pre-tensioning gear disc are both higher than the radial teeth, so that the radial teeth can be used to receive the driving force provided by the pre-tensioning rod in the seat belt retractor and drive the pre-tensioning gear disc to rotate, and then the force limiting rod drives the reel to rotate and rewind the seat belt; The tooth tips of the radial teeth are configured as convex tooth top structures, and the maximum height of the convex tooth top structures is higher than the height of the first end of the preloaded gear plate. The radial teeth are configured with the convex tooth top structures to have an impact strength 10%-30% higher than that of radial teeth with straight tooth top structures. A ratchet structure with one-way ratchet teeth is provided in the outer convex circle on the second end of the reel, and a plurality of radial protrusions arranged at intervals are provided on the outer peripheral surface of the first end of the pre-tightening gear plate. The ratchet structure is used to cooperate with the radial protrusion structure, so that when the pre-tightening gear plate rotates forward after the radial teeth are driven by driving force, the force limiting rod and the reel are synchronously driven to rotate, and when the pre-tightening gear plate rotates reversely after the radial teeth lose driving force, the pre-tightening gear plate is disengaged from the reel to reduce the force limiting fluctuation.

2. The pretensioning assembly of the seat belt retractor according to claim 1, characterized in that: The convex tooth top structure of the radial teeth partially follows the first end of the preload gear plate and is embedded in the outer convex circle on the second end of the winding shaft.

3. The pretensioning assembly of the seat belt retractor according to claim 1, characterized in that: The preload gear plate is fixedly connected to the force limiting rod through an integral plastic-wrapped structure.

4. The pretensioning assembly of the seat belt retractor according to claim 3, characterized in that: A plurality of holes are arranged on the end face of the second end of the pre-tightening gear plate, which are used for integrally wrapping and fixing the pre-tightening gear plate and the force limiting rod, and for facilitating the mold ejector to push the end face of the force limiting rod to be demoulded after the wrapping and fixing.

5. The pretensioning assembly of the seat belt retractor according to claim 3, characterized in that: The preload gear plate is made of high-strength polymer injection molding or metal mixture die casting.

6. The pretensioning assembly of a seat belt retractor according to any one of claims 1 to 5, characterized in that: The first end of the force-limiting rod is provided with a first spline, and the first end of the force-limiting rod and the first end of the reel are fixedly connected after interference fit through the first spline; And / or, the second end of the force limiting rod is provided with a second spline, and the second end of the force limiting rod is fixedly connected to the preload gear plate via the second spline; And / or, the force limiting rod is a metal force limiting rod.

7. A seat belt retractor, characterized in that: The invention comprises a pre-tensioning assembly of a seat belt retractor according to any one of claims 1 to 6.

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