Pre-tightening type two-stage self-adaptive force-limiting safety belt retractor

Abstract

The invention provides a pre-tightening type two-stage self-adaptive force limiting safety belt retractor which comprises a frame assembly, a coil spring component, a smoke and fire switching clutch device, a two-stage force limiting assembly, a mandrel assembly, a smoke and fire type pre-tightening device and a vehicle sensing / belt sensing assembly, and the smoke and fire switching clutch device comprises a lifting ring, a smoke and fire triggering module, a switching shell and a slope. The smoke and fire triggering module is detachably arranged on the switching shell; the lifting ring is arranged in the switching shell relative to the smoke and fire triggering module, and the core shaft assembly is sleeved with the lifting ring. And the lifting ring can be lifted to a corresponding height after being in contact with the slope. The mandrel assembly comprises a mandrel, a sleeve, a fixing ring, a fixing ring and a locking block, the fixing ring is buckled to the first end of the mandrel in a sleeving mode, the locking block is inserted into the circumferential end face of the sleeve, circumferential rotation of the locking block is limited by the fixing ring, and the fixing ring is arranged on the fixing ring in a sleeving mode and meanwhile pressed to the radial end face of the lifting ring. Connection and separation of the mandrel relative to the sleeve are achieved through the assembling relation of the fixing ring, the fixing ring and the locking block relative to the sleeve.

Description

Technical Field

[0001] This application relates to the field of seat belt retractor technology, specifically to a pre-tensioned two-stage adaptive force-limiting seat belt retractor. Background Technology

[0002] With the development of vehicle electrification and intelligence, seat belts need to have both passive safety protection and active pretensioning functions. They are usually equipped with an irreversible pyrotechnic pretensioning device (which quickly retracts the webbing to eliminate gaps during a collision) and a reversible active pretensioning device (including a motor and clutch, which pretensions the webbing in danger and unlocks it after the danger is over). The two devices need to work together without interfering with each other.

[0003] To meet vehicle regulations, single, constant seatbelt force limiters or fixed-angle switchable force limiters are increasingly insufficient to meet occupant protection requirements. Therefore, a switchable force limiter retractor with customizable switching time is needed to optimize occupant injury metrics and meet the design requirements of frontal restraint systems. However, existing customizable switchable force limiters often integrate the pyrotechnic triggering structure with the switching housing, resulting in complex assembly processes.

[0004] Therefore, how to achieve custom adjustment of the seat belt retractor force limit level, improve switching efficiency, and reduce the impact of switching delay on the performance protection of the restraint system has become a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This application provides a pre-tensioned two-stage adaptive force-limiting seat belt retractor to solve the problem of how to achieve customized adjustment of the force-limiting level of the seat belt retractor in the prior art, thereby improving switching efficiency and reducing the performance protection problem of the restraint system that may be caused by switching delay.

[0006] This application provides a pretensioning two-stage adaptive force-limiting seatbelt retractor, including a frame assembly, a coil spring component, a pyrotechnic switching clutch device, a two-stage force-limiting assembly, a spindle assembly, a pyrotechnic pretensioning device, and a vehicle-feel / belt-feel assembly. The pyrotechnic switching clutch is located on the first side of the frame assembly. The pyrotechnic switching clutch includes a lifting ring, a pyrotechnic triggering module, a switching housing, and a ramp. The pyrotechnic triggering module is detachable from the switching housing. The lifting ring is located in the switching housing relative to the pyrotechnic triggering module, and the lifting ring is fitted onto the spindle assembly. The ramp is located in the switching housing, and the lifting ring can be lifted to a corresponding height after contacting the ramp. The pyrotechnic pretensioning device is located on the second side of the frame assembly; The mandrel assembly is disposed between the pyrotechnic switching clutch and the pyrotechnic pre-tightening device; the mandrel assembly includes a mandrel, a sleeve, a retaining ring, a retaining ring, and a locking block. The retaining ring is fitted onto the first end of the mandrel. The locking block is inserted into the circumferential end face of the sleeve and its circumferential rotation is restricted by the retaining ring. The retaining ring is fitted onto the retaining ring and simultaneously pressed against the radial end face of the lifting ring, restricting the movement of the locking block in the radial direction. The mandrel achieves connection and separation relative to the sleeve through the assembly relationship between the retaining ring, the retaining ring, and the locking block relative to the sleeve. The secondary force limiting component is disposed inside the sleeve. The secondary force limiting component includes a higher-order force limiting rod and a lower-order force limiting rod, which are connected in series via a spline connection structure. The seat belt retractor is configured with a pre-tensioning stage and a force-limiting stage. In the pre-tensioning stage: at the initial stage of the collision, the pyrotechnic pre-tensioning device triggers high-pressure gas to push the steel ball inside the tube to strike the ball gear and rotate clockwise. The ball gear and the secondary force-limiting component work together to drag the webbing back up. The force-limiting stage: During the collision, the occupant's upper torso continues to shift, the webbing is pulled out and drives the spindle to rotate counterclockwise. At this time, the pyrotechnic pre-tensioning device is in a pressure-holding state. When the webbing tension reaches a preset value, the high-order torsion bar twists and deforms to apply resistance to the rotation of the spindle, so as to slowly release a small amount of webbing, reduce the pressure on the occupant's chest, and achieve the first stage of force limitation. Then the pyrotechnic switching clutch is activated, and the pyrotechnic triggering module can push the lifting ring to move upward along the slope of the switching housing while separating the fixing ring from the fixing ring. The spindle rotates and squeezes the locking block out of the spindle. The sleeve in the spindle separates, and the low-order torsion bar twists and deforms to achieve the second stage of force limitation.

[0007] Optionally, the switching housing includes a switching support frame, a first receiving cavity, a first through hole, a connecting hole, and a limiting member; The switching support frame is connected to the first side of the frame assembly; The first accommodating cavity is formed at the first end of the switching support frame; multiple ramps are provided, and the multiple ramps are spaced apart on the radial cavity wall of the first accommodating cavity; the annular body of the lifting ring is disposed in the first accommodating cavity relative to the ramps; The first through hole extends through the first receiving cavity, and the first end of the mandrel passes through the first through hole and is received in the first receiving cavity; The limiting member is disposed on the circumferential cavity wall of the first accommodating cavity, and the limiting member has a limiting gap relative to the bottom of the first accommodating cavity, and the lifting ring is restricted in the limiting gap; The connecting hole is located on the circumferential cavity wall of the first accommodating cavity, and the trigger end of the lifting ring passes through the connecting hole and is positioned opposite to the pyrotechnic triggering module.

[0008] Optionally, the pyrotechnics triggering module includes: an ignition base, an ignition torch, a disassembly structure, a sealing piston, and a sealing ring; The disassembly and assembly structure is disposed between the ignition base and the switching support frame, and the ignition base is disassembled and assembled to the switching support frame through the disassembly and assembly structure. The sealing piston is movably mounted on the output end of the ignition base, and the ignition torch is mounted on the end of the ignition base; the sealing piston has ribs. The sealing ring is fitted onto the circumferential end face of the sealing piston; The pyrotechnic triggering module is configured such that: the ignition torch generates high-pressure gas to push out the sealing piston, and the sealing piston pushes the lifting ring to move upward along the slope of the switching housing while separating the fixing ring from the fixing ring.

[0009] Optionally, the disassembly and assembly structure includes an assembly groove, an assembly structure, and a riveting structure; The assembly slot is formed at the second end of the switching support frame; The assembly structure is located on the outside of the ignition base. The assembly structure has a shape that is adapted to the assembly slot. The ignition base can be snapped into the assembly slot through the assembly structure. After the ignition base is installed in the assembly slot, the riveting structure can encapsulate the ignition base in the assembly slot.

[0010] Optionally, the lifting ring has a circular body, the circular body is connected to the first radial end face of the fixed ring, and multiple movable openings are spaced apart on the edge of the circular body. When the lifting ring is installed in the first accommodating cavity, each ramp is arranged in each movable opening. In the circumferential direction, an inclined guide platform is provided on one side of the movable opening, and the inclined end face of the guide platform can contact the slope surface.

[0011] Optionally, the locking block has a first arcuate portion, a second arcuate portion, and a third arcuate portion; The first arcuate portion is adapted to the first receiving groove on the circumferential end face of the sleeve, and the first arcuate portion is installed in the first receiving groove; The second arc portion connects with the first arc portion, and the second arc portion is fitted into the edge of the first receiving groove; and the arc distributions of the first arc portion and the second arc portion are opposite. The third arc portion is located on the opposite side of the first arc portion, and the third arc portion is adapted to the circumferential inner end face of the fixing ring.

[0012] Optionally, the locking block includes a first locking block and a second locking block symmetrically arranged with the first end of the mandrel as the center.

[0013] Optionally, the fixing ring includes: a ring body, a fitting groove, a second through hole, a snap-fit ​​structure, a limiting support component, and a limiting structure; The fitting groove is formed at the radial end of the ring body; The second through hole extends through the bottom of the fitting groove, and after the end of the mandrel passes through the second through hole, part of the mandrel is fitted into the fitting groove; The snap-fit ​​structure is disposed on the circumferential groove wall of the mounting groove and the circumferential end face of the first end of the mandrel, and the fixing ring is fastened to the first end of the mandrel through the snap-fit ​​structure; The limiting support component is disposed on the circumferential groove wall of the fitting groove, and the limiting support component can be relatively limited and supported on the first radial end face and the second radial end face of the fixing ring. The limiting structure is disposed on the circumferential groove wall of the mounting groove, and the limiting structure can restrict the movement of the locking block in the circumferential direction.

[0014] Optionally, the limiting support assembly includes a first limiting support and a second limiting support; The first limiting support is disposed on the circumferential groove wall of the sleeve groove, and the first limiting support is limited and supported on the first radial end face of the fixing ring; The second limiting support is disposed on the circumferential groove wall of the sleeve groove and located on the side of the first limiting support, and the second limiting support is limited and supported on the second radial end face of the fixing ring.

[0015] Optionally, the spline connection structure includes a first spline, a second spline, a first spline groove, and a second spline groove; The first spline can be installed in the spline positioning groove on the inner wall of the sleeve; The second spline protrudes from the first radial end face of the first spline; The first spline groove is recessed on the second radial end face of the first spline; The second spline groove is recessed on the radial end face of the first end of the higher-order force-limiting rod; The first end of the low-order force limiting rod is installed in the first spline groove, and the second spline is installed in the second spline groove.

[0016] Compared with the prior art, this application has the following advantages: This application provides a pre-tensioned two-stage adaptive force-limiting seatbelt retractor, including a frame assembly, a coil spring assembly, a pyrotechnic switching clutch device, a two-stage force-limiting assembly, a spindle assembly, a pyrotechnic pre-tensioning device, and a vehicle-feel / belt-feel assembly. The pyrotechnic switching clutch device is located on the first side of the frame assembly and includes a lifting ring, a pyrotechnic trigger module, a switching housing, and a ramp. The pyrotechnic trigger module is detachably mounted to the switching housing. The lifting ring is disposed within the switching housing relative to the pyrotechnic trigger module and is fitted onto the spindle assembly. The ramp is located within the switching housing, and the lifting ring is raised to a corresponding height upon contact with the ramp. The pyrotechnic pre-tensioning device is located on the second side of the frame assembly. The mandrel assembly is positioned between the pyrotechnic switching clutch and the pyrotechnic pre-tightening device. The mandrel assembly includes a mandrel, a sleeve, a retaining ring, a retaining ring, and a locking block. The retaining ring is fitted onto the first end of the mandrel. The locking block is inserted into the circumferential end face of the sleeve and its circumferential rotation is restricted by the retaining ring. The retaining ring is fitted onto the retaining ring and simultaneously presses against the radial end face of the lifting ring, restricting the radial movement of the locking block. The mandrel's connection and separation from the sleeve are achieved through the assembly relationship between the retaining ring, retaining ring, and locking block relative to the sleeve. A secondary force-limiting assembly is located inside the sleeve. The secondary force-limiting assembly includes a higher-order force-limiting rod and a lower-order force-limiting rod, which are connected in series via a spline connection structure.

[0017] The seatbelt retractor is configured with a pre-tensioning stage and a force-limiting stage. In the pre-tensioning stage: initially after impact, the pyrotechnic pre-tensioning device triggers high-pressure gas, pushing a steel ball inside the tube to strike a ball-gear, which rotates clockwise. The ball-gear, integrated with the secondary force-limiting component, pulls the webbing back in. In the force-limiting stage: during the impact, the occupant's upper torso continuously shifts, pulling out the webbing and causing the spindle to rotate counter-clockwise. At this time, the pyrotechnic pre-tensioning device is in a pressure-holding state. When the webbing tension reaches a preset value, the higher-order torsion bar twists and deforms, applying resistance to the spindle's rotation to slowly release a small amount of webbing, reducing pressure on the occupant's chest and achieving the first stage of force limiting. Subsequently, the pyrotechnic switching clutch is activated. The pyrotechnic trigger module pushes the lifting ring upwards along the slope of the switching housing, simultaneously separating the fixing ring from the fixing ring. The spindle rotation forces the locking block out of the spindle, separating the sleeve within the spindle. The lower-order torsion bar twists and deforms, achieving the second stage of force limiting.

[0018] This application's pre-tensioned two-stage adaptive force-limiting safety belt retractor, through its split-type trigger design, decouples the pyrotechnic triggering module and the switching housing, reducing assembly process requirements. Furthermore, the simpler and more reliable locking block design allows for customized adjustment of the force-limiting level, further reducing component and assembly process requirements and improving component reliability and switching efficiency. In addition, the high-order force-limiting bar is connected to the sleeve via a spline, and the shape of the low-order force-limiting bar connector and the high-order connecting groove are simpler to shape and control, while also ensuring connection strength. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a pretensioner provided in an embodiment of this application.

[0020] Figure 2 This is a cross-sectional view of the pretensioner provided in the embodiments of this application.

[0021] Figure 3 This is an exploded view of the pretensioner provided in the embodiments of this application.

[0022] Figure 4 This is a schematic diagram of the structure of the pyrotechnic switching clutch device provided in the embodiments of this application.

[0023] Figure 5 This is an exploded view of the pyrotechnic switching clutch device provided in the embodiments of this application.

[0024] Figure 6 This is a schematic diagram of the switching housing provided in an embodiment of this application.

[0025] Figure 7 This is a structural schematic diagram of the switching housing provided in this application embodiment from another angle.

[0026] Figure 8 This is a schematic diagram of the lifting ring provided in an embodiment of this application.

[0027] Figure 9 This is a cross-sectional view of the pyrotechnic switching clutch device provided in the embodiments of this application.

[0028] Figure 10 This is a schematic diagram of the structure of the fireworks triggering module provided in the embodiments of this application.

[0029] Figure 11 This is a schematic diagram of the structure of the ignition base provided in the embodiment of this application.

[0030] Figure 12 This is a schematic diagram of the structure of the sealing piston provided in the embodiment of this application.

[0031] Figure 13 This is a schematic diagram of the mandrel assembly provided in the embodiments of this application.

[0032] Figure 14 This is an exploded view of the mandrel assembly provided in the embodiments of this application.

[0033] Figure 15 yes Figure 14 Enlarged view of point A in the middle.

[0034] Figure 16 This is a schematic diagram of the structure of the fixing ring provided in an embodiment of this application.

[0035] Figure 17 This is a schematic diagram of the structure of the locking block provided in an embodiment of this application.

[0036] Figure 18 This is a schematic diagram of the structure provided in this application, showing the locking block installed between the sleeve and the mandrel.

[0037] Figure 19 This is a schematic diagram of the structure of the secondary force limiting component provided in the embodiments of this application.

[0038] Figure 20 This is an exploded view of the secondary force limiting component provided in the embodiments of this application.

[0039] Figure 21 This is a cross-sectional view of the secondary force limiting component provided in the embodiments of this application.

[0040] Figure 22 This is a schematic diagram of the spline connection structure provided in the embodiments of this application.

[0041] Figure label: Frame assembly 1, coil spring component 2, pyrotechnic switching clutch device 3, lifting ring 30, annular body 301, trigger end 302, movable opening 303, guide platform 304, pyrotechnic trigger module 31, ignition base 311, first receiving part 3111, second receiving part 3112, first receiving cavity 3113, second receiving cavity 3114, ignition torch 312, disassembly and assembly structure 313, assembly groove 3131, column groove 3132, first snap-fit ​​groove 3133, second snap-fit ​​groove 3134, assembly structure 3 14. Column 3141, first annular protrusion 3142, second annular protrusion 3143, sealing piston 316, sealing end 3161, contact end 3162, sealing ring 317, sealing groove 318, rib 319, switching housing 32, switching support frame 321, first accommodating cavity 322, radial cavity wall 3221, circumferential cavity wall 3222, switching opening 3223, first through hole 323, connecting hole 324, limiting member 325, support connection part 3251, inner limiting protrusion 32 52; ramp 33, spindle assembly 4, spindle 41, first receiving groove 411, sleeve 42, limiting rib 422, fixing ring 43, fixing ring 44, fitting groove 441, second through hole 442, first limiting hook 4431, first connecting part 44311, hook 44312, second receiving groove 4432, limiting support assembly 444, first limiting support 4441, second connecting part 44411, support arm 44412, second limiting support 4442, third connecting part 44 421, outer limiting protrusion 44422, limiting structure 445, first connecting post 4451, second connecting post 4452, limiting groove 4453; locking block 45, first arc portion 451, second arc portion 452, third arc portion 453, secondary force limiting component 5, high-order force limiting rod 51, low-order force limiting rod 52, spline connection structure 53, first spline 531, second spline 532, first spline groove 533, second spline groove 534; pyrotechnic pre-tensioning device 6, vehicle feel / belt feel component 7. Detailed Implementation

[0042] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0043] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] With the development of vehicle electrification and intelligence, seat belts need to have both passive safety protection and active pretensioning functions. They are usually equipped with an irreversible pyrotechnic pretensioning device (which quickly retracts the webbing to eliminate gaps during a collision) and a reversible active pretensioning device (including a motor and clutch, which pretensions the webbing in danger and unlocks it after the danger is over). The two devices need to work together without interfering with each other.

[0046] To meet vehicle regulations, single, constant seatbelt force limiting or fixed-angle switchable force limiting functions are increasingly insufficient to meet occupant protection requirements. Therefore, a switchable force limiting retractor with customizable switching time is needed to optimize occupant injury indicators and meet the design requirements of front restraint systems. However, existing customizable switchable force limiting retractors often integrate the pyrotechnic triggering structure with the switching housing (32 structure), resulting in complex assembly processes.

[0047] Therefore, how to achieve custom adjustment of the seat belt retractor force limit level, improve switching efficiency, and reduce the impact of switching delay on the performance protection of the restraint system has become a problem that urgently needs to be solved by those skilled in the art.

[0048] Accordingly, this application provides a pre-tensioned two-stage adaptive force-limiting seatbelt retractor, including a frame assembly, a coil spring assembly, a pyrotechnic switching clutch device, a two-stage force-limiting assembly, a spindle assembly, a pyrotechnic pre-tensioning device, and a vehicle-feel / belt-feel assembly. The pyrotechnic switching clutch device is located on the first side of the frame assembly and includes a lifting ring, a pyrotechnic trigger module, a switching housing, and a ramp. The pyrotechnic trigger module is detachably mounted to the switching housing. The lifting ring is disposed within the switching housing relative to the pyrotechnic trigger module and is fitted onto the spindle assembly. The ramp is located within the switching housing, and the lifting ring is raised to a corresponding height upon contact with the ramp. The pyrotechnic pre-tensioning device is located on the second side of the frame assembly. The mandrel assembly is positioned between the pyrotechnic switching clutch and the pyrotechnic pre-tightening device. The mandrel assembly includes a mandrel, a sleeve, a retaining ring, a retaining ring, and a locking block. The retaining ring is fitted onto the first end of the mandrel. The locking block is inserted into the circumferential end face of the sleeve and its circumferential rotation is restricted by the retaining ring. The retaining ring is fitted onto the retaining ring and simultaneously presses against the radial end face of the lifting ring, restricting the radial movement of the locking block. The mandrel's connection and separation from the sleeve are achieved through the assembly relationship between the retaining ring, retaining ring, and locking block relative to the sleeve. A secondary force-limiting assembly is located inside the sleeve. The secondary force-limiting assembly includes a higher-order force-limiting rod and a lower-order force-limiting rod, which are connected in series via a spline connection structure.

[0049] The seatbelt retractor is configured with a pre-tensioning stage and a force-limiting stage. In the pre-tensioning stage: initially after impact, the pyrotechnic pre-tensioning device triggers high-pressure gas, pushing a steel ball inside the tube to strike a ball-gear, which rotates clockwise. The ball-gear, integrated with the secondary force-limiting component, pulls the webbing back in. In the force-limiting stage: during the impact, the occupant's upper torso continuously shifts, pulling out the webbing and causing the spindle to rotate counter-clockwise. At this time, the pyrotechnic pre-tensioning device is in a pressure-holding state. When the webbing tension reaches a preset value, the higher-order torsion bar twists and deforms, applying resistance to the spindle's rotation to slowly release a small amount of webbing, reducing pressure on the occupant's chest and achieving the first stage of force limiting. Subsequently, the pyrotechnic switching clutch is activated. The pyrotechnic trigger module pushes the lifting ring upwards along the slope of the switching housing, simultaneously separating the fixing ring from the fixing ring. The spindle rotation forces the locking block out of the spindle, separating the sleeve within the spindle. The lower-order torsion bar twists and deforms, achieving the second stage of force limiting. During the force-limiting phase, the spindle is considered a moving part, while the smoke-type warning and frame locking are considered as a single unit (fixed).

[0050] This application's pre-tensioned two-stage adaptive force-limiting safety belt retractor, through its split-type trigger design, decouples the pyrotechnic triggering module and the switching housing, reducing assembly process requirements. Furthermore, the simpler and more reliable locking block design allows for customized adjustment of the force-limiting level, further reducing component and assembly process requirements and improving component reliability and switching efficiency. In addition, the high-order force-limiting bar is connected to the sleeve via a spline, and the shape of the low-order force-limiting bar connector and the high-order connecting groove are simpler to shape and control, while also ensuring connection strength.

[0051] The pre-tensioned two-stage adaptive force-limiting seat belt retractor provided in this application will now be described in detail with reference to the accompanying drawings.

[0052] like Figures 1 to 22 As shown, this application provides a pre-tensioned two-stage adaptive force-limiting seat belt retractor, including a frame assembly 1, a coil spring component 2, a pyrotechnic switching clutch device 3, a two-stage force-limiting assembly 5, a spindle assembly 44, a pyrotechnic pre-tensioning device 6, and a vehicle-feel / belt-feel assembly 7. The pyrotechnic switching clutch device 3 is located on the first side of the frame assembly 1. The pyrotechnic switching clutch device 3 includes a lifting ring 30, a pyrotechnic trigger module 31, a switching housing 32, and a ramp 33. The pyrotechnic trigger module 31 is detachably mounted to the switching housing 32. The lifting ring 30 is disposed in the switching housing 32 relative to the pyrotechnic trigger module 31, and the lifting ring 30 is fitted onto the spindle assembly 44. The ramp 33 is located in the switching housing 32, and the lifting ring 30 can be lifted to a corresponding height after contacting the ramp 33. The pyrotechnic pre-tensioning device 6 is located on the second side of the frame assembly 1. The spindle assembly 44 is disposed between the pyrotechnic switching clutch device 3 and the pyrotechnic pre-tightening device 6. The spindle assembly 44 includes a spindle 41, a sleeve 42, a retaining ring 43, a retaining ring 44, and a locking block 45. The retaining ring 44 is fitted onto the first end of the spindle 41. The locking block 45 is inserted into the circumferential end face of the sleeve 42 and its circumferential rotation is restricted by the retaining ring 44. The retaining ring 43 is fitted onto the retaining ring 44 and simultaneously pressed against the radial end face of the lifting ring 30, restricting the movement of the locking block 45 in the radial direction. The spindle 41 is connected and separated from the sleeve 42 through the assembly relationship between the retaining ring 43, the retaining ring 44, and the locking block 45 relative to the sleeve 42. The secondary force limiting assembly 5 is disposed inside the sleeve 42. The secondary force limiting assembly 5 includes a high-order force limiting rod 51 and a low-order force limiting rod 52, which are connected in series through a spline connection structure 53.

[0053] The seatbelt retractor is configured with a pretensioning stage and a force-limiting stage. In the pretensioning stage: initially after a collision, the pyrotechnic pretensioning device 6 triggers high-pressure gas to push a steel ball inside the tube, causing the ball gear to rotate clockwise. The ball gear, integrated with the secondary force-limiting component 5, pulls the webbing back in. In the force-limiting stage: during the collision, the occupant's upper torso continues to shift, pulling the webbing out and causing the spindle 41 to rotate counterclockwise. At this time, the pyrotechnic pretensioning device 6 is in a pressure-holding state. When the webbing tension reaches a preset value, the higher-order torsion bar twists and deforms, applying resistance to the rotation of the spindle 41 to slowly release a small amount of webbing, reducing pressure on the occupant's chest and achieving the first stage of force limiting. Immediately, the pyrotechnic switching clutch 3 is activated, and the pyrotechnic trigger module 31 can push the lifting ring 30 to move upward along the slope 33 of the switching housing 32, while separating the fixing ring 43 from the fixing ring 44. The spindle 41 rotates and squeezes the locking block 45 out of the spindle 41. The spindle 41 separates and integrates with the pyrotechnic warning and frame locking. The low-order torsion bar twists and deforms to achieve the second stage of force limiting.

[0054] The specific structures of the frame assembly 1, the coil spring component 2, the pyrotechnic pretensioning device 6, and the vehicle-feel / belt-feel assembly 7 are conventional designs and will not be described in detail here. This embodiment will provide a detailed description of the specific structures of the pyrotechnic switching clutch device 3, the secondary force limiting assembly 5, and the spindle assembly 44.

[0055] Specifically, in this embodiment, the pyrotechnic switching clutch 3 is disposed on the first side of the frame assembly 1. The pyrotechnic switching clutch 3 includes a lifting ring 30, a pyrotechnic triggering module 31, a switching housing 32, and a ramp 33. The pyrotechnic triggering module 31 is detachably mounted to the switching housing 32. The lifting ring 30 is disposed in the switching housing 32 relative to the pyrotechnic triggering module 31, and the lifting ring 30 is fitted onto the spindle assembly 44. The ramp 33 is disposed in the switching housing 32, and the lifting ring 30 can be lifted to a corresponding height after contacting the ramp 33.

[0056] Furthermore, in this embodiment, the switching housing 32 includes a switching support frame 321, a first accommodating cavity 322, a first through hole 323, a connecting hole 324, and a limiting member 325. The switching support frame 321 is connected to the first side of the frame assembly 1. In one example, the switching support frame 321 is cuboid in shape and adapted to the first side of the frame assembly 1. The first accommodating cavity 322 is formed at the first end of the switching support frame 321, which is the end of the switching support frame 321 facing the coil spring member 2. The first accommodating cavity 322 is recessed at the center of the first end of the switching support frame 321. The radial cross-section of the first accommodating cavity 322 is circular, and the first accommodating cavity 322 has a radial cavity wall 3221, a circumferential cavity wall 3222, and a switching opening 3223, which is located at the first end of the switching support frame 321. Multiple ramps 33 are provided, and the multiple ramps 33 are spaced apart from the radial cavity wall 3221 of the first accommodating cavity 322. The annular body 301 of the lifting ring 30 is disposed in the first receiving cavity 322 relative to the slope 33, specifically arranged in the radial cavity wall 3221 of the first receiving cavity 322. The first through hole 323 is disposed through the first receiving cavity 322, specifically through the radial cavity wall 3221 of the first receiving cavity 322. The first end of the mandrel 41 passes through the first through hole 323 and is received in the first receiving cavity 322.

[0057] A limiting member 325 is disposed on the circumferential cavity wall 3222 of the first accommodating cavity 322. The limiting member 325 has a limiting gap relative to the bottom of the first accommodating cavity 322, and the lifting ring 30 is confined in the limiting gap. A connecting hole 324 is disposed on the circumferential cavity wall 3222 of the first accommodating cavity 322. The trigger end 302 of the lifting ring 30 passes through the connecting hole 324 and is disposed opposite to the pyrotechnic triggering module 31. In one example, the limiting member 325 includes a supporting connecting portion 3251 and an inner limiting protrusion 3252. The supporting connecting portion 3251 extends circumferentially along the first accommodating cavity 322, and the inner limiting protrusion 3252 protrudes radially from the inner end face of the supporting connecting portion 3251. The inner limiting protrusion 3252 and the supporting connecting portion 3251 form a limiting angle, and the edge of the annular body 301 is attached to the limiting angle. It should be noted that the inner limiting protrusion 3252 has a certain degree of elasticity, and it can lose its limiting function when the lifting ring 30 is in action. In one example, the circumferential cavity wall 3222 of the first accommodating cavity 322 is provided with through holes at intervals, preferably configured to have through holes evenly distributed circumferentially in the circumferential cavity wall 3222 of the first accommodating cavity 322. The support connecting part 3251 is correspondingly disposed in the through hole.

[0058] In one example, the switching housing 32 further includes an encapsulation plate that is encapsulated at the first end of the switching support frame 321 to encapsulate the switching opening 3223 of the first receiving cavity 322. The encapsulation plate is plate-shaped and its shape is adapted to the first end of the switching support frame.

[0059] The lifting ring 30 is disposed in the switching housing 32 relative to the pyrotechnic triggering module 31, and is fitted onto the spindle assembly 44. In this embodiment, the annular body 301 of the lifting ring 30 is circular, connected to the first radial end face of the fixed ring 43, and has multiple movable openings 303 spaced apart along its edge. When the lifting ring 30 is installed in the first accommodating cavity 322, each ramp 33 is correspondingly arranged in each movable opening 303. Furthermore, in the circumferential direction of the lifting ring 30, an inclined guide platform 304 is provided on one side of each movable opening 303, the inclined end face of which can contact the slope surface of the ramp 33. In this embodiment, the ramp 33 gradually rises counterclockwise. That is, the pyrotechnics triggering module 31 drives the triggering end 302 of the lifting ring 30 to make the main body of the lifting ring 30 rotate relative to the slope 33, and the guide platform 304 on the main body of the lifting ring 30 moves from the lower part to the higher part of the slope 33.

[0060] The pyrotechnics triggering module 31 is detachable from the switching housing 32. The pyrotechnics triggering module 31 includes: an ignition base 311, an ignition torch 312, a disassembly / reassembly structure 313, a sealing piston 316, and a sealing ring 317. Specifically, in this embodiment, the ignition base 311 has a first receiving portion 3111 and a second receiving portion 3112 that are mutually connected. The first receiving portion 3111 is used to receive the sealing piston 316, and the second receiving portion 3112 is used to receive the ignition torch 312. In one example, the main body of each of the first receiving portion 3111 and the second receiving portion 3112 has a columnar structure. The first receiving portion 3111 and the second receiving portion 3112 respectively have a first receiving cavity 3113 and a second receiving cavity 3114. The sealing piston 316 is received in the first receiving cavity 3113, and the ignition torch 312 is received in the second receiving cavity 3114.

[0061] A disassembly / assembly structure 313 is disposed between the ignition base 311 and the switching support frame 321. The ignition base 311 is disassembled and assembled to the switching support frame 321 via the disassembly / assembly structure 313. In this embodiment, the disassembly / assembly structure 313 includes an assembly groove 3131, an assembly structure 314, and a riveting structure. The assembly groove 3131 is formed at the second end of the switching support frame 321, and the second end of the switching support frame 321 is opposite to the first end. In one example, the assembly groove 3131 includes a column groove 3132, a first snap-fit ​​groove 3133, and a second snap-fit ​​groove 3134. The column groove 3132 is arranged vertically, and the first snap-fit ​​groove 3133 and the second snap-fit ​​groove 3134 are distributed along the extension direction of the column groove 3132. The first snap-fit ​​groove 3133 and the second snap-fit ​​groove 3134 are perpendicular to and surround the column groove 3132, and communicate with the column groove 3132. The first card slot 3133 and the second card slot 3134 form a square ring around the column slot 3132.

[0062] The assembly structure 314 is located on the outside of the ignition base 311. The assembly structure 314 has a shape adapted to the assembly groove 3131, allowing the ignition base 311 to be snapped into the assembly groove 3131. Specifically, corresponding to the shape of the assembly structure 314, it has a column 3141 and a first annular protrusion 3142 and a second annular protrusion 3143 distributed along the axial direction of the column 3141 on its circumferential end face. When the column 3141 is inserted into the column groove 3132, the first annular protrusion 3142 is inserted into the first snap-fit ​​groove 3133, and the second annular protrusion 3143 is inserted into the second snap-fit ​​groove 3134, thereby snapping the ignition base 311 onto the second end of the switching support frame 321. In one example, the assembly structure 314 is located on the outside of the first receiving portion 3111 of the ignition base 311.

[0063] After the ignition base 311 is snapped into the assembly slot 3131, the riveting structure can encapsulate the ignition base 311 in the assembly slot 3131.

[0064] A sealing piston 316 is movably mounted on the output end of the ignition base 311 (i.e., in the first receiving cavity 3113), and an ignition torch 312 is mounted on the end of the ignition base 311 (i.e., in the second receiving cavity 3114). A sealing ring 317 is fitted onto the circumferential end face of the sealing piston 316. In one example, the sealing piston 316 includes an integrally formed sealing end 3161 and a contact end 3162. The circumferential end face of the sealing end 3161 is provided with two sealing grooves 318, which are distributed annularly along the circumferential end face of the sealing end 3161. The sealing ring 317 is fitted into the sealing grooves 318. Of course, in other examples, the number of sealing grooves 318 on the circumferential end face of the sealing end 3161 can be set according to actual needs. The contact end 3162 is provided with ribs 319, which are distributed axially along the sealing piston 316. In one example, three ribs 319 are provided, and the ribs 319 are evenly distributed along the circumferential end face of the sealing piston 316. The sealing piston 316 has two sealing rings 317 to prevent gas leakage and reduce pressure, thus serving to maintain pressure and provide thrust. The three ribs on the sealing piston 316 are in linear contact, reducing ejection friction.

[0065] The pyrotechnic triggering module 31 is configured such that: the ignition torch 312 generates high-pressure gas that pushes out the sealing piston 316; the sealing piston 316 pushes the lifting ring 30 upward along the ramp 33 of the switching housing 32, simultaneously separating the fixing ring 43 from the fixing ring 44. In this embodiment, the pyrotechnic triggering module 31 and the switching housing 32 are designed separately and then assembled together, simplifying the assembly process and facilitating production control.

[0066] The spindle assembly 44 is positioned between the pyrotechnic switching clutch 3 and the pyrotechnic pre-tightening device 6. The spindle assembly 44 includes a spindle 41, a sleeve 42, a retaining ring 43, a retaining ring 44, and a locking block 45. The retaining ring 44 is fitted onto the first end of the spindle 41. The locking block 45 is inserted into the circumferential end face of the sleeve 42 and its circumferential rotation is restricted by the retaining ring 44. The retaining ring 43 is fitted onto the retaining ring 44 and simultaneously presses against the radial end face of the lifting ring 30, restricting the radial movement of the locking block 45. The connection and separation of the spindle 41 relative to the sleeve 42 are achieved through the assembly relationship of the retaining ring 43, the retaining ring 44, and the locking block 45 relative to the sleeve 42.

[0067] Specifically, in this embodiment, the fixing ring 44 includes a ring body, a fitting groove 441, a second through hole 442, a snap-fit ​​structure, a limiting support assembly 444, and a limiting structure 445. The fitting groove 441 is formed at the radial end of the ring body. The second through hole 442 extends through the bottom of the fitting groove 441, and the end of the mandrel 41 passes through the second through hole 442, after which a portion of the mandrel 41 is fitted into the fitting groove 441. The snap-fit ​​structure is disposed on the circumferential groove wall of the fitting groove 441 and the circumferential end face of the first end of the mandrel 41, and the fixing ring 44 is fastened to the first end of the mandrel 41 by the snap-fit ​​structure. The limiting support assembly 444 is disposed on the circumferential groove wall of the fitting groove 441, and the limiting support assembly 444 can be relatively limited and supported on the first and second radial end faces of the fixing ring 43. The limiting structure 445 is disposed on the circumferential groove wall of the fitting groove 441, and the limiting structure 445 can restrict the movement of the locking block 45 in the circumferential direction. In one example, multiple clip-on structures, limit support components 444, and limit structures 445 are respectively configured on the mounting slot 441.

[0068] Furthermore, in this embodiment, the overall structure of the ring body approximates a hollowed-out pedestal, and it has no bottom surface. Of course, in one example description, the ring body includes a flat ring body and a circumferential ring body, with the circumferential ring body integrally formed perpendicularly to the circumference of the flat ring body. The fitting groove 441 is formed by the flat ring body and the circumferential ring body. One side of the fitting groove 441 is open, and a second through hole 442 penetrates the bottom of the fitting groove 441. After the end of the mandrel 41 passes through the second through hole 442, a portion of the mandrel 41 is fitted into the fitting groove 441.

[0069] The locking structure includes a first limiting hook 4431 and a second receiving groove 4432. The first limiting hook 4431 includes a first connecting portion 44311 and a hook 44312. The first connecting portion 44311 is part of the circumferential groove wall of the fitting groove 441. Alternatively, in other examples, the first connecting portion 44311 may be a part independent of the circumferential groove wall of the fitting groove 441, meaning the first connecting portion 44311 is axially connected to the edge of the flat ring body of the ring. The hook 44312 is connected to the end of the first connecting portion 44311 and is perpendicular to it. The second receiving groove 4432 is located on the circumferential end face of the first end of the mandrel 41 and is opposite to the hook 44312. The hook 44312 can be locked in the second receiving groove 4432. After the hook 44312 is locked in the second receiving groove 4432, it restricts the axial movement of the fixing ring 44 relative to the mandrel 41. In one example, multiple card-mounted structures are set on the mounting slot 441. In this example, four are preferably distributed at intervals around the circumference of the mounting slot 441.

[0070] The limiting support assembly 444 includes a first limiting support member 4441 and a second limiting support member 4442. The first limiting support member 4441 is disposed on the circumferential groove wall of the fitting groove 441, and is limited and supported by the first radial end face of the fixing ring 43. The second limiting support member 4442 is disposed on the circumferential groove wall of the fitting groove 441 and located on the side of the first limiting support member 4441, and is limited and supported by the second radial end face of the fixing ring 43. In one example, the second limiting support member 4442 is located on both sides of the first limiting support member 4441 in the circumferential direction. Furthermore, in one example, the first limiting support 4441 includes a second connecting portion 44411 and a support arm 44412, with the second connecting portion 44411 serving as part of the circumferential groove wall of the fitting groove 441. Of course, in other examples, the second connecting portion 44411 is a portion independent of the circumferential groove wall of the fitting groove 441, i.e., the second connecting portion 44411 is axially connected to the edge of the flat ring body of the ring. The support arm 44412 is connected to the end of the second connecting portion 44411 and is perpendicularly connected to it. The first radial end face of the fixing ring 43 is abutted against the support arm 44412.

[0071] In one example, the second limiting support 4442 includes a third connecting portion 44421 and an outer limiting protrusion 44422. The third connecting portion 44421 extends circumferentially along the fitting groove 441, or the third connecting portion 44421 is part of the circumferential groove wall of the fitting groove 441, or the third connecting portion 44421 is axially connected to the edge of the flat ring body of the ring body. The outer limiting protrusion 44422 protrudes radially from the outer end face of the third connecting portion 44421, and the outer limiting protrusion 44422 and the third connecting portion 44421 form a limiting angle, with the second radial end face of the fixing ring 43 abutting against the limiting angle. It should be noted that the outer limiting protrusion 44422 has a certain elasticity, and the outer limiting protrusion 44422 may lose its limiting function when the fixing ring 43 is in action.

[0072] In one example, four first limiting support members 4441 are set at equal intervals along the circumference of the fixing ring 44. Correspondingly, four second limiting support members 4442 are set at equal intervals along the circumference of the fixing ring 44, that is, there is one second limiting support member 4442 between every two adjacent first limiting support members 4441.

[0073] In this embodiment, the limiting structure 445 includes a first connecting post 4451, a second connecting post 4452, and a limiting groove 4453. The first connecting post 4451 and the second connecting post 4452 extend circumferentially along the fitting groove 441 (distributed circumferentially in the fitting groove 441), and the ends of each of the first connecting post 4451 and the second connecting post 4452 are located at opposite ends of the locking block 45 in the circumferential direction. The limiting groove 4453 is formed at the ends of each of the first connecting post 4451 and the second connecting post 4452, and the openings of the limiting groove 4453 face opposite ends of the locking block 45 in the circumferential direction. The opposite ends of the locking block 45 in the circumferential direction are respectively limited within the limiting groove 4453.

[0074] In this embodiment, the locking block 45 has a first arcuate portion 451, a second arcuate portion 452, and a third arcuate portion 453. The first arcuate portion 451 is adapted to the first receiving groove 411 on the circumferential end face of the sleeve 42, and is installed in the first receiving groove 411. The second arcuate portion 452 connects to the first arcuate portion 451 and is engaged with the edge of the first receiving groove 411, with the arc lines of the first and second arcuate portions 451 and 452 being opposite. The third arcuate portion 453 is located on the opposite side of the first arcuate portion 451, and is adapted to the circumferential inner end face of the fixing ring 43.

[0075] In one example, the first receiving groove 411 and the second receiving groove 4432 are interconnected, and the first receiving groove 411 is located below the second receiving groove 4432.

[0076] In one example, the locking block 45 includes a first locking block and a second locking block symmetrically arranged with the first end of the spindle 41 as the center. That is, there are two locking blocks 45.

[0077] The spindle assembly 44 provided in this embodiment has a simple structural design, simple parts manufacturing process, and is easy to implement.

[0078] In this embodiment, the secondary force limiting component 5 is disposed inside the sleeve 42. The secondary force limiting component 5 includes a higher-order force limiting rod 51 and a lower-order force limiting rod 52, which are connected in series via a spline connection structure 53. Specifically, in one example, the spline connection structure 53 includes a first spline 531, a second spline 532, a first spline groove 533, and a second spline groove 534. The first spline 531 can be installed in a spline positioning groove on the inner wall of the sleeve 42. The second spline 532 protrudes from the first radial end face of the first spline 531, with the first radial end face of the first spline 531 facing the higher-order force limiting rod 51. The first spline groove 533 is recessed in the second radial end face of the first spline 531, with the second radial end face of the first spline 531 facing the lower-order force limiting rod 52. The second spline groove 534 is recessed in the radial end face of the first end of the higher-order force limiting rod 51. The first end of the low-order force limiting rod 52 is installed in the first spline groove 533, and the second spline 532 is installed in the second spline groove 534.

[0079] In one example, the diameter of the first spline 531 is larger than the diameter of the second spline 532.

[0080] In one example, the outer contour of the first spline 531 is consistent with the outer contour of the first end of the higher-order force limiter 51.

[0081] In one example, the first spline 531 is interference-fitted with the spline positioning groove on the inner wall of the sleeve 42.

[0082] In one example, the inner wall of the sleeve 42 is provided with a limiting rib 422, and the thickness of the limiting rib 422 gradually increases in the direction from the first end to the second end of the sleeve 42.

[0083] In one example, the sleeve 42 is further provided with a first receiving groove 411, which is distributed on the circumferential end face of the sleeve 42. The first receiving groove 411 is used to receive the locking block 45. The first receiving groove 411 is provided at equal intervals on the circumferential end face of the sleeve 42, and there are two of them.

[0084] In this embodiment, a spline connection structure 53 is provided between the high-order force limiting rod 51 and the low-order force limiting rod 52, and the high-order force limiting rod 51 and the low-order force limiting rod 52 are connected in series through the spline connection structure 53, so that the connection between the high-order force limiting rod 51 and the low-order force limiting rod 52 is more stable, thereby improving the stability of the force limiting.

[0085] In one example, the higher-order force-limiting rod 51 and the lower-order force-limiting rod 52 are connected by other structures, such as square-head structures, where the ends of the higher-order force-limiting rod 51 and the lower-order force-limiting rod 52 are set as square-head structures. Alternatively, the ends of the higher-order force-limiting rod 51 and the lower-order force-limiting rod 52 can be set as spline structures or square-head structures. Specifically, the first square head can be installed in a square-head positioning groove on the inner wall of the sleeve 42. The second square head protrudes from the first radial end face of the first square head, and the first radial end face of the first square head faces the higher-order force-limiting rod 51. The first square head groove is recessed in the second radial end face of the first square head, and the second radial end face of the first square head faces the lower-order force-limiting rod 52. The second square head groove is recessed in the radial end face of the first end of the higher-order force-limiting rod 51. The first end of the lower-order force-limiting rod 52 is installed in the first square head groove, and the second square head is installed in the second square head groove.

[0086] This application provides a pre-tensioned two-stage adaptive force-limiting seat belt retractor, including a frame assembly 1, a coil spring component 2, a pyrotechnic switching clutch device 3, a two-stage force-limiting assembly 5, a spindle assembly 44, a pyrotechnic pre-tensioning device 6, and a vehicle-feel / belt-feel assembly 7. The pyrotechnic switching clutch device 3 is located on the first side of the frame assembly 1 and includes a lifting ring 30, a pyrotechnic trigger module 31, a switching housing 32, and a ramp 33. The pyrotechnic trigger module 31 is detachably mounted to the switching housing 32. The lifting ring 30 is disposed in the switching housing 32 relative to the pyrotechnic trigger module 31 and is fitted onto the spindle assembly 44. The ramp 33 is located in the switching housing 32, and the lifting ring 30 can be raised to a corresponding height upon contact with the ramp 33. The pyrotechnic pre-tensioning device 6 is located on the second side of the frame assembly 1. The spindle assembly 44 is disposed between the pyrotechnic switching clutch device 3 and the pyrotechnic pre-tightening device 6. The spindle assembly 44 includes a spindle 41, a sleeve 42, a retaining ring 43, a retaining ring 44, and a locking block 45. The retaining ring 44 is fitted onto the first end of the spindle 41. The locking block 45 is inserted into the circumferential end face of the sleeve 42 and its circumferential rotation is restricted by the retaining ring 44. The retaining ring 43 is fitted onto the retaining ring 44 and simultaneously pressed against the radial end face of the lifting ring 30, restricting the movement of the locking block 45 in the radial direction. The spindle 41 is connected and separated from the sleeve 42 through the assembly relationship between the retaining ring 43, the retaining ring 44, and the locking block 45 relative to the sleeve 42. The secondary force limiting assembly 5 is disposed inside the sleeve 42. The secondary force limiting assembly 5 includes a high-order force limiting rod 51 and a low-order force limiting rod 52, which are connected in series through a spline connection structure 53.

[0087] The seatbelt retractor is configured with a pretensioning stage and a force-limiting stage. In the pretensioning stage: initially after a collision, the pyrotechnic pretensioning device 6 triggers high-pressure gas to push a steel ball inside the tube, causing the ball gear to rotate clockwise. The ball gear, integrated with the secondary force-limiting component 5, pulls the webbing back in. In the force-limiting stage: during the collision, the occupant's upper torso continues to shift, pulling the webbing out and causing the spindle 41 to rotate counterclockwise. At this time, the pyrotechnic pretensioning device 6 is in a pressure-holding state. When the webbing tension reaches a preset value, the higher-order torsion bar twists and deforms, applying resistance to the rotation of the spindle 41 to slowly release a small amount of webbing, reducing pressure on the occupant's chest and achieving the first stage of force limiting. Immediately, the pyrotechnic switching clutch 3 is activated, and the pyrotechnic trigger module 31 can push the lifting ring 30 to move upward along the slope 33 of the switching housing 32, while separating the fixing ring 43 from the fixing ring 44. The spindle 41 rotates and squeezes the locking block 45 out of the spindle 41. The spindle 41 separates and integrates with the pyrotechnic warning and frame locking. The low-order torsion bar twists and deforms to achieve the second stage of force limiting.

[0088] This application's pre-tensioned two-stage adaptive force-limiting safety belt retractor, through its split-trigger design, decouples the pyrotechnic trigger module 31 from the switching housing 32, reducing assembly process requirements. Furthermore, the simpler and more reliable locking block 45 design allows for customized adjustment of the force-limiting level, further reducing component and assembly process requirements and improving component reliability and switching efficiency. Additionally, the high-order force-limiting rod 51 is connected to the sleeve 42 via a spline connection, while the lower-order force-limiting rod 52's connector shape and high-order connecting groove process are simpler, easier to form and control, and simultaneously ensure connection strength.

[0089] It should be noted that although several structures, components, or units for implementing the relevant functions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to the specific embodiments of this application, the features and functions of two or more structures, components, or units described above can be embodied in one structure, component, or unit. Conversely, the features and functions of one structure, component, or unit described above can be further divided and embodied by multiple components, structures, or units.

[0090] Furthermore, although the various components of the components or apparatus in this application and the mounting arrangements between them are described in a specific order in the accompanying drawings, this does not require or imply that the components or apparatus must be designed according to that specific component or mounting arrangement, or that all the components shown must be included to achieve the desired result. Additional or alternative components may be omitted, multiple components may be combined into one component to achieve the corresponding function, and / or a component may be decomposed into multiple components to achieve the corresponding function, etc.

[0091] Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A pre-tensioned two-stage adaptive force-limiting seatbelt retractor, comprising a frame assembly, a coil spring assembly, a pyrotechnic switching clutch device, a two-stage force-limiting assembly, a spindle assembly, a pyrotechnic pre-tensioning device, and a vehicle-feel / belt-feel assembly, characterized in that, The pyrotechnic switching clutch is located on the first side of the frame assembly. The pyrotechnic switching clutch includes a lifting ring, a pyrotechnic triggering module, a switching housing, and a ramp. The pyrotechnic triggering module is detachable from the switching housing. The lifting ring is located in the switching housing relative to the pyrotechnic triggering module, and the lifting ring is fitted onto the spindle assembly. The ramp is located in the switching housing, and the lifting ring can be lifted to a corresponding height after contacting the ramp. The pyrotechnic pretensioning device is located on the second side of the frame assembly; The mandrel assembly is disposed between the pyrotechnic switching clutch and the pyrotechnic pre-tightening device; the mandrel assembly includes a mandrel, a sleeve, a retaining ring, a retaining ring, and a locking block. The retaining ring is fitted onto the first end of the mandrel. The locking block is inserted into the circumferential end face of the sleeve and its circumferential rotation is restricted by the retaining ring. The retaining ring is fitted onto the retaining ring and simultaneously pressed against the radial end face of the lifting ring, restricting the movement of the locking block in the radial direction. The mandrel achieves connection and separation relative to the sleeve through the assembly relationship between the retaining ring, the retaining ring, and the locking block relative to the sleeve. The secondary force limiting component is disposed inside the sleeve. The secondary force limiting component includes a higher-order force limiting rod and a lower-order force limiting rod, which are connected in series via a spline connection structure. The seat belt retractor is configured with a pre-tensioning stage and a force-limiting stage. In the pre-tensioning stage: at the initial stage of the collision, the pyrotechnic pre-tensioning device triggers high-pressure gas to push the steel ball inside the tube to strike the ball gear and rotate clockwise. The ball gear and the secondary force-limiting component work together to drag the webbing back up. The force-limiting stage: During the collision, the occupant's upper torso continues to shift, the webbing is pulled out and drives the spindle to rotate counterclockwise. At this time, the pyrotechnic pre-tensioning device is in a pressure-holding state. When the webbing tension reaches a preset value, the high-order torsion bar twists and deforms to apply resistance to the rotation of the spindle, so as to slowly release a small amount of webbing, reduce the pressure on the occupant's chest, and achieve the first stage of force limitation. Then the pyrotechnic switching clutch is activated, and the pyrotechnic triggering module can push the lifting ring to move upward along the slope of the switching housing while separating the fixing ring from the fixing ring. The spindle rotates and squeezes the locking block out of the spindle. The sleeve in the spindle separates, and the low-order torsion bar twists and deforms to achieve the second stage of force limitation.

2. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 1, characterized in that, The switching housing includes a switching support frame, a first accommodating cavity, a first through hole, a connecting hole, and a limiting member; The switching support frame is connected to the first side of the frame assembly; The first accommodating cavity is formed at the first end of the switching support frame; multiple ramps are provided, and the multiple ramps are spaced apart on the radial cavity wall of the first accommodating cavity; the annular body of the lifting ring is disposed in the first accommodating cavity relative to the ramps; The first through hole extends through the first receiving cavity, and the first end of the mandrel passes through the first through hole and is received in the first receiving cavity; The limiting member is disposed on the circumferential cavity wall of the first accommodating cavity, and the limiting member has a limiting gap relative to the bottom of the first accommodating cavity, and the lifting ring is restricted in the limiting gap; The connecting hole is located on the circumferential cavity wall of the first accommodating cavity, and the trigger end of the lifting ring passes through the connecting hole and is positioned opposite to the pyrotechnic triggering module.

3. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 2, characterized in that, The pyrotechnics triggering module includes: an ignition base, an ignition torch, a disassembly and assembly structure, a sealing piston, and a sealing ring; The disassembly and assembly structure is disposed between the ignition base and the switching support frame, and the ignition base is disassembled and assembled to the switching support frame through the disassembly and assembly structure. The sealing piston is movably mounted on the output end of the ignition base, and the ignition torch is mounted on the end of the ignition base; the sealing piston has ribs. The sealing ring is fitted onto the circumferential end face of the sealing piston; The pyrotechnic triggering module is configured such that: the ignition torch generates high-pressure gas to push out the sealing piston, and the sealing piston pushes the lifting ring to move upward along the slope of the switching housing while separating the fixing ring from the fixing ring.

4. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 3, characterized in that, The disassembly / assembly structure includes an assembly groove, an assembly structure, and a riveting structure; The assembly slot is formed at the second end of the switching support frame; The assembly structure is located on the outside of the ignition base. The assembly structure has a shape that is adapted to the assembly slot. The ignition base can be snapped into the assembly slot through the assembly structure. After the ignition base is installed in the assembly slot, the riveting structure can encapsulate the ignition base in the assembly slot.

5. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 2, characterized in that, The lifting ring has a circular body that is connected to the first radial end face of the fixed ring. Multiple movable openings are provided at intervals along the edge of the circular body. When the lifting ring is installed in the first accommodating cavity, each ramp is arranged in each movable opening. In the circumferential direction, an inclined guide platform is provided on one side of the movable opening, and the inclined end face of the guide platform can contact the slope surface.

6. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 1, characterized in that, The locking block has a first arc portion, a second arc portion, and a third arc portion; The first arcuate portion is adapted to the first receiving groove on the circumferential end face of the sleeve, and the first arcuate portion is installed in the first receiving groove; The second arc portion connects with the first arc portion, and the second arc portion is fitted into the edge of the first receiving groove; and the arc distributions of the first arc portion and the second arc portion are opposite. The third arc portion is located on the opposite side of the first arc portion, and the third arc portion is adapted to the circumferential inner end face of the fixing ring.

7. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 1, characterized in that, The locking block includes a first locking block and a second locking block symmetrically arranged with the first end of the mandrel as the center.

8. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 1, characterized in that, The fixing ring includes: a ring body, a fitting groove, a second through hole, a snap-fit ​​structure, a limiting support component, and a limiting structure; The fitting groove is formed at the radial end of the ring body; The second through hole extends through the bottom of the fitting groove, and after the end of the mandrel passes through the second through hole, part of the mandrel is fitted into the fitting groove; The snap-fit ​​structure is disposed on the circumferential groove wall of the mounting groove and the circumferential end face of the first end of the mandrel, and the fixing ring is fastened to the first end of the mandrel through the snap-fit ​​structure; The limiting support component is disposed on the circumferential groove wall of the fitting groove, and the limiting support component can be relatively limited and supported on the first radial end face and the second radial end face of the fixing ring. The limiting structure is disposed on the circumferential groove wall of the mounting groove, and the limiting structure can restrict the movement of the locking block in the circumferential direction.

9. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 8, characterized in that, The limiting support assembly includes a first limiting support member and a second limiting support member; The first limiting support is disposed on the circumferential groove wall of the sleeve groove, and the first limiting support is limited and supported on the first radial end face of the fixing ring; The second limiting support is disposed on the circumferential groove wall of the sleeve groove and located on the side of the first limiting support, and the second limiting support is limited and supported on the second radial end face of the fixing ring.

10. The pre-tensioned two-stage adaptive force-limiting seat belt retractor according to claim 1, characterized in that, The spline connection structure includes a first spline, a second spline, a first spline groove, and a second spline groove; The first spline can be installed in the spline positioning groove on the inner wall of the sleeve; The second spline protrudes from the first radial end face of the first spline; The first spline groove is recessed on the second radial end face of the first spline; The second spline groove is recessed on the radial end face of the first end of the higher-order force-limiting rod; The first end of the low-order force limiting rod is installed in the first spline groove, and the second spline is installed in the second spline groove.

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