CN102923091A - Torsion bar for safety belt retractor, safety belt retractor and safety belt assembly - Google Patents

Abstract

The invention provides a torsion bar for a safety belt retractor. The torsion bar is rod-like, peripheral outer teeth are arranged at two ends and in the middle of the torsion bar, the outer teeth at the two ends of the torsion bar are matched with inner teeth of central concave holes in the end faces of two end covers on the retractor, and the peripheral outer teeth in the middle of the torsion bar are matched with inner teeth on the middle section of a through hole in the middle axis of a core shaft; and the axial length of the torsion bar is not greater than that of a scroll. The torsion bar is shortened, so that bending deformation of the torsion bar is avoided, the torsion bar is not subjected to other restraint outside the end covers on the two sides, the overall stress condition of the torsion bar is simplified, and the torsion bar is safe and stable in use. The invention simultaneously provides the safety belt retractor using the torsion bar and a safety belt assembly.

Description

Torsion bar for safety belt retractor, safety belt retractor and safety belt assembly

Technical Field

The invention relates to a safety belt technology, in particular to a torsion bar for a safety belt retractor. The invention also relates to a safety belt retractor and a safety belt assembly using the torsion bar.

Background

Safety belts are important passive safety components for automotive applications. When the vehicle is in collision, the safety belt can protect a user and prevent or reduce secondary injury during collision.

A standard three-point harness originally designed for use in a car seat includes only a latch mechanism and webbing for securing a user (human body). When the vehicle is collided, the locking mechanism is locked, the mesh belt is not stretched outwards any more, and therefore a user is bound on the automobile seat. However, since the speed changes rapidly at the moment of impact, the momentum change time caused by the speed change at the time of impact is short, so that the force of the webbing on the user is large, for example, up to 8-10 kN. Can lead to even more severe injury by breaking the ribs of the user.

Based on the reasons, the standard safety belt is further improved, and a force limiting type safety belt is provided, namely at the moment of collision, the force of the woven belt acting on a human body can be limited through a certain force limiting mechanism, so that the human body cannot be injured by the woven belt, and the purpose of protecting a user to the maximum extent is achieved.

European patent document EP1607288B1 discloses a safety device for a force-limiting safety belt. Specifically, in the second embodiment of the european patent document, the safety device is disclosed to include a U-shaped frame, a spool, and a torsion bar. And circular holes with internal teeth are formed in two opposite side walls of the U-shaped frame. The reel comprises a mandrel for winding the braid and separate end covers arranged at two ends of the mandrel. The end cover is provided with external teeth matched with the internal teeth on the frame; the spool is rotatable float set up in on the U type frame, and both end covers set up respectively in the circular port of U type frame, under normal condition, the external tooth on the end cover with the internal tooth of circular port is not meshed, and the spool can rotate in the circular port to the winding meshbelt or release meshbelt.

The torsion bar is in a rod shape, is arranged in the reel along the axis of the reel and is connected with the reel in a way of meshing the inner teeth and the outer teeth at the central position of the reel along the axis; in addition, two ends of the torsion bar penetrate through the centers of the two end covers, extend out of the end covers and are meshed with the inner teeth on the two end covers through outer teeth.

The working process of the force limiting type mounting device is as follows: in the event of a collision, the sensing device triggers an actuating mechanism including a gas generator, so that external teeth on the end cover of the winding shaft are meshed with internal teeth of the U-shaped frame, and the winding shaft is changed from a rotatable floating state (also called a free state) to a locked state. So that the webbing wound on the spool is no longer released outwardly. Thereby securing the user to the seat. In the process, the greater the force to which the webbing is subjected from the forward movement of the user due to inertia, the force always trying to pull the spool of the spool into rotation. The spindle is fixed to the U-shaped frame by a torsion bar engaged therewith and an end cap engaged with the torsion bar so as not to rotate. When the traction force of meshbelt is enough big can make the torsion bar produce the distortion and rotate, the rotation of certain angle will take place for the dabber to make the meshbelt can be released one section length, and then make the user can produce certain displacement forward, alleviate the meshbelt and act on the pulling force on the user, reached the effect of restriction meshbelt action on the user's power on one's body, obtain the limit power effect.

The important characteristic of above-mentioned patent lies in that the torsion bar both ends are fixed, and the middle section is through inside and outside tooth meshing dabber for torsional deformation evenly distributed prevents local stress concentration and fracture on whole torsion bar, and can make full use of the material of torsion bar, produces stable unanimous limit force effect. In addition, the torsion bar has symmetrical deformation process, so that the retractor frame is stressed in balance, and the torsional deformation of the frame is small.

For details of the force-limiting type mounting device of the above patent document, reference is further made to the above european patent document.

However, the force-limiting safety device disclosed in the above-mentioned european patent also has certain drawbacks. The main problem is that the two ends of the torsion bar extending out of the end caps are also subjected to constraint force from other structures, so that the whole torsion bar is stressed complexly, and local stress concentration is easy to generate to cause fracture failure. The force limiting safety device disclosed in the european patent has a problem that the extension of the torsion bar is complicated because the torsion bar is stressed in a large relationship with the extension in the torsion direction, making it difficult to control the force limiting value more precisely.

In addition, the torsion bar needs to be processed by a cold pressing process to ensure the consistency of the characteristics, the longer the part is, the higher the processing difficulty and the manufacturing cost of the die are, and the torsion bar provided by the above european patent is longer, so that the cost is high and the manufacturing difficulty is high.

Disclosure of Invention

The present invention provides a torsion bar for a seat belt to solve the above-mentioned problems of the torsion bar of the conventional seat belt retractor. The present invention additionally provides a retractor and a seatbelt assembly using the torsion bar.

The invention provides a torsion bar for a safety belt retractor, wherein the safety belt retractor comprises a retractor frame and a reel, the reel comprises a mandrel which is provided with a through hole along a central axis and is used for winding a braid, and two end covers which are separately arranged at two ends of the mandrel respectively; a central concave hole with internal teeth is formed in the end cover in the central position facing the inner end face of the mandrel; internal teeth are arranged at the middle section of the through hole at the axis position of the mandrel;

the torsion bar is in a rod shape, the two end parts and the middle part of the torsion bar are respectively provided with circumferential external teeth, the external teeth at the two end parts of the torsion bar are matched with the internal teeth of the central concave hole at the end surfaces of the two end covers on the retractor, and the circumferential external teeth at the middle part of the torsion bar are matched with the internal teeth arranged at the middle section of the through hole at the central axis position of the mandrel; wherein the length of the torsion bar in the axial direction is not greater than the axial length of the spool.

Preferably, the circumferential external teeth arranged at the middle part of the torsion bar are provided with avoidance tooth notches;

preferably, the circumferentially outer teeth provided at one end portion thereof are provided with an anti-missing tooth notch at a position corresponding to the aforementioned missing tooth notch.

Preferably, the external tooth profile of the torsion bar in the middle part is inclined to the end part provided with the mistake-proofing notch.

Preferably, the position of the avoiding tooth segment corresponds to a fixing groove which is formed in the mandrel and penetrates through and fixes the end part of the mesh belt.

The invention provides a safety belt retractor, which comprises a retractor frame, a reel and a torsion bar for the safety belt retractor, wherein the torsion bar is used for the safety belt retractor; wherein,

the retractor frame comprises two opposite side walls; circular holes with internal teeth are formed in the positions corresponding to the two side walls;

the reel comprises a mandrel and two end covers, wherein the mandrel is provided with a through hole along the central axis and is used for winding a braid, and the two end covers are detachably arranged at two ends of the mandrel respectively; the end cover is provided with external teeth along the periphery, and a central concave hole with internal teeth is arranged at the central position facing the inner end surface of the mandrel; internal teeth are arranged at the middle section of the through hole at the axis position of the mandrel;

the torsion bar penetrates through the through hole of the mandrel, and the external teeth at the middle part are meshed with the internal teeth on the inner wall of the through hole of the mandrel; two ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the scroll, and external teeth at the two ends are meshed with internal teeth of the central concave holes of the inner end surfaces of the end covers; the torsion bar has stable ductility in circumferential torsion;

in a free state, the reel is rotatably and floatingly arranged in the retractor frame, and two end covers are arranged in circular holes on two side walls of the retractor frame; when the reel is locked, the external teeth of the two end covers of the reel are meshed with the internal teeth on the frame.

The invention also provides a safety belt assembly, and the safety belt retractor adopting the technical scheme is used.

Compared with the prior art, the torsion bar provided by the invention has the advantages that the two ends of the torsion bar are arranged at the two end covers of the reel without penetrating out of the end covers, and compared with the torsion bar in the background art, the length of the torsion bar is shortened; the portion that protrudes outside in the related art is replaced with a protruding shaft that is provided outside the end cover in the seatbelt retractor. When a vehicle using the safety belt with the torsion bar provided by the invention collides, the braid drives the mandrel to rotate and drives the torsion bar to rotate through the internal teeth of the middle section; the end caps are locked to the frame and engage both ends of the torsion bar so that both ends of the torsion bar cannot rotate. When the torsion force is large enough, the torsion bar will be twisted and deformed, so that the mandrel will rotate at a certain angle to release part of the woven belt, and the force of the woven belt on the body of the user can be reduced. The length of the torsion bar adopted by the invention is shorter than that in the background technology, and the torsion bar does not extend out of the end covers along the axial direction, so that the torsion bar is not easy to bend and deform, and is not restrained by other parts except the end covers at two sides, the whole stress condition of the torsion bar is simplified, and the use process is safer and more stable. The torsion bar is not easy to bend and deform, the relative angle between the mandrel and the end cover can be maintained, and local metal friction and gluing between the mandrel and the end cover cannot be caused. In addition, because the material of the torsion bar needs to meet the special torsion requirement, the cost is high, the manufacturing requirement is high, and the short torsion bar can save the cost and reduce the manufacturing difficulty.

Drawings

Fig. 1 is a schematic structural view of an embodiment of a retractor for a seatbelt of the present invention;

FIG. 2 is a schematic view of the reel of FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 2 taken along the axial direction of the spool;

FIG. 4 is an exploded view of the spool assembly and torsion bar assembly;

FIG. 5 is a schematic structural view of an embodiment of a torsion bar of the present invention;

FIG. 6 shows an end profile of the left end of the torsion bar of FIG. 5;

FIG. 7 is a fitting view showing the left end portion of the torsion beam inserted into the recessed hole of the left end cap;

FIG. 8 is an end profile of the right end of the torsion bar shown in FIG. 5;

FIG. 9 is a view showing a state where the right end of the torsion bar is inserted into the recess hole of the right end cap

FIG. 10 is a schematic view of a torsion bar with a central external tooth having a notched opening inserted into a mandrel with the external tooth fitting in a through hole of the mandrel;

fig. 11 shows a perspective view of the torsion beam;

fig. 12 shows a cross-sectional view of the torsion beam.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather construed as limited to the embodiments set forth herein.

Please refer to fig. 5, which is a schematic structural diagram of a torsion bar according to the present invention. In this embodiment, the torsion bar 3 is a rod shape, and has external teeth 3-2a and external teeth 3-2b provided at both ends and a middle portion thereof in a circumferential direction. Outer teeth at two end parts of the torsion bar 3 are matched with inner teeth of central concave holes in end surfaces of two end covers on the retractor, and circumferential outer teeth in the middle of the torsion bar are matched with inner teeth arranged in the middle section of a through hole in the central axis position of the mandrel; wherein the length of the torsion bar in the axial direction is not greater than the axial length of the spool.

For a better understanding of the torsion bar of the present embodiment, the torsion bar of the present invention will be described in detail below in conjunction with a seatbelt retractor to which the torsion bar is applied. It should be noted that in the present embodiment, other components of the seatbelt retractor are mainly described for better understanding of the torsion bar of the present embodiment, and the description should not be construed as limiting the scope of the claims of the present application.

Referring to fig. 1, which is a schematic structural view of one of the retractors for a seatbelt of the present invention, referring to fig. 1, the retractor includes a retractor frame 1, a spool 2, and the above-mentioned torsion bar 3 (shown in fig. 4) in the present embodiment

Wherein, coiler frame 1 is the U type, and it includes two relative lateral walls: a first side wall 1-1 and a second side wall 1-2. And two third walls 1-4 connecting the first side wall 1-1 and the second side wall 1-2. A first circular through hole 1-1a and a second circular through hole 1-2a are respectively arranged at corresponding positions on the first side wall 1-1 and the second side wall 1-2, and an internal tooth section 1-3 is arranged at the same position on the two through holes (fig. 1 only shows that the internal tooth section is arranged on the second through hole 1-2 a). The inner tooth sections 1-3 are used for being matched with the outer teeth on the reel to lock the reel, so that the arrangement positions of the inner tooth sections 1-3 correspond to the traction direction of the woven belt wound on the reel. In the frame shown in said fig. 1, the webbing is led out from the top of the inside of said third wall 1-4, so that said inner tooth segments 1-3 are arranged at the top of both through holes.

Other structures, such as lightening holes on the two side walls, interfaces of reinforcing ribs connecting the two side walls, and the like, are also arranged on the frame 1, and are not described in detail herein.

Please refer to fig. 2, 3 and 4, wherein fig. 2 is a schematic structural view of the reel in fig. 1; FIG. 3 is a cross-sectional view of FIG. 2 taken along the axial direction of the spool; fig. 4 is an exploded view of the spool and torsion bar assembly.

The reel 2 comprises a mandrel 2-1 and end covers which are arranged at two ends of the mandrel 2-1 in a separable mode: a left end cap 2-2a and a right end cap 2-2 b. The spindle 2-1 is used for winding a webbing belt, and it can be rotated along its axis to wind a webbing belt thereon or to release the wound webbing belt. The mandrel is provided with a through hole 2-3 along the axis, and the inner wall of the through hole 2-3 is provided with inner teeth.

Two pin columns 2-6 which extend outwards are respectively arranged on two end faces of the mandrel 2-1 and are called force limiting pins 2-6.

And a flat and long fixing groove 2-4 for penetrating and fixing the end part of the braid and a lightening groove 2-5 for lightening weight are also arranged on the mandrel 2-1.

The periphery of the two end covers is provided with external teeth, as shown in fig. 4, the periphery of the left end cover 2-2a is provided with external teeth 2-2a-1, the periphery of the right end cover 2-2b is provided with an external gear ring 2-2b-1, the teeth on the two end covers are all one-way teeth, the rotation direction of the mandrel 2-1 is towards the release direction of the woven tape, and the external teeth on the periphery of the two end covers are matched with the internal gear segments of the two through holes on the frame 1.

And pin holes are also arranged on the end surfaces of the two end covers facing the mandrel 2-1 at positions corresponding to the force limiting pins, such as the pin holes 2-2b-2 on the right end cover 2-2b shown in figure 4. When both end caps are provided on both end faces of the core shaft 2-1 in the manner shown in fig. 2, force-limiting pins are inserted into the corresponding pin holes. In addition, the force limiting pin can be arranged on the inner side of the end cover, and a pin hole is arranged at the corresponding position of the end face of the mandrel 2-1. The force limiting pins can be arranged at different positions at two ends of the mandrel, so that the force limiting pins can be used for positioning when the end covers are assembled with the mandrel 2-1, and assembly errors of the left end cover and the right end cover are prevented. More importantly, the force limiting pins 2-6 can also bear the shearing force generated when the mandrel rotates, and can be cut off when the shearing force reaches a threshold value.

The end face centers of the two end covers facing the mandrel 2-1 are also provided with central concave holes (hereinafter referred to as concave holes) with internal teeth, such as concave holes 2-2b-3 on the right end cover 2-2b shown in fig. 4. In this embodiment, the concave holes of the two end caps are disposed on the bosses extending out of the side of the end faces where the concave holes are located. The corresponding end surface of the mandrel is provided with a spigot for accommodating the boss.

And an outward extending shaft extending outwards is arranged along the center of the outer end faces (namely the end faces far away from the mandrel 2-1) of the two end covers. A right side protruding shaft 2-2b-5 as shown in fig. 1 and a left side protruding shaft 2-2a-5 as shown in fig. 4. Wherein, the left side projecting shaft 2-2a-5 is connected with the sensing element, and the periphery of the right side projecting shaft 2-2b-5 is provided with teeth which are connected with the coil spring.

In using the torsion bar of the present embodiment in a retractor reel, as shown in fig. 2, 3 and 4, the torsion bar 3 is inserted into and passed through the through-hole 2-3 of the spindle 2-1, and the outer teeth of the axially central portion thereof are engaged with the inner teeth provided on the inner wall of the through-hole 2-3 of the spindle 2-1. The left end cover 2-2a and the right end cover 2-2b respectively cover the two end parts of the mandrel 2-1 from the left side and the right side, and force limiting pins at corresponding positions correspond to the pin holes. The two ends of the torsion bar 3 are respectively inserted into the concave holes of the left end cover and the right end cover, and the external teeth of the end parts of the torsion bar are meshed with the internal teeth of the corresponding concave holes.

With continued reference to fig. 4, a wear-reducing ring 4b is further disposed between the bosses of the two end caps and the spigot of the mandrel 2-1. The friction reducing ring 4b is generally made of low-friction plastic and can provide transition for the matched spigot position between the opposite end surfaces of the end cover 2-2 and the mandrel 2-1, so that metal surfaces at the spigot position cannot be in direct contact, and the influence of the gluing effect caused by mutual friction of the metal surfaces on the normal work of the torsion bar is avoided.

With continued reference to fig. 4, an annular boss (an annular boss 2-2b-6 on the right-side end cover shown in fig. 4) is disposed on the outer edge of the inner side of the end cover, and an avoiding spigot matched with the annular boss is disposed at a corresponding position on the end surface of the mandrel 2-1; through the arrangement of the annular boss and the avoidance spigot structure, the friction area of the end face of the mandrel 2-1 and the end cover during relative rotation can be reduced, so that the friction force between the mandrel and the end cover is reduced, and the stability of the force limiting effect is improved.

The reel 2 is integrally arranged in the frame 1, and two end covers on the reel 2 are respectively arranged in through holes on the side wall of the frame 1. In a free state, the scroll 2 is rotatably and floatingly arranged in the retractor frame 1, and external teeth on an end cover of the scroll are not in contact with internal teeth of a through hole in the retractor frame 1. The reel 2 is supported by the extending shafts outside the two ends of the end cover, and the reel 2 can rotate freely to wind and release the mesh belt. And when the reel 2 is locked, the outer teeth of the two end covers of the reel 2 are meshed with the inner teeth of the corresponding positions on the frame 1, and the reel 2 cannot rotate.

In the retractor of the present embodiment, the two ends of the torsion bar 3 are disposed at the two end covers of the spool without penetrating the end covers, and the length of the torsion bar is shortened compared to the torsion bar in the related art. The shortened portion is replaced by a protruding shaft disposed outside the end cap. When the safety belt using the torsion bar in the embodiment is in collision, the braid drives the mandrel to rotate, and then the torsion bar is driven to rotate. The end caps are locked to the frame and engage both ends of the torsion bar so that both ends of the torsion bar cannot rotate. The middle part of the torsion bar 3 is meshed with the internal teeth of the mandrel 2-1 through the circumferential external teeth at the middle part, so that the torsion bar bears the pulling force of the braid, and the two end parts are fixed due to the meshing relationship between the external teeth at the end parts and the gear at the inner end surface of the end cover 2-2; when the pulling force of the woven belt reaches a certain degree, the torsion bar 3 is twisted and deformed, so that the mandrel 2-1 rotates at a certain angle to release part of the woven belt, the twisted and deformed characteristic of the torsion bar 3 can properly release the woven belt, the binding force of the woven belt on a human body is controlled at a preset value, and the damage of an overlarge binding force on the human body is avoided; meanwhile, the woven belt can not be released for too long distance to cause failure of binding to the human body.

Therefore, the torsion bar is shortened, and the boss on the inner side of the end cover and the spigot of the core shaft are arranged, so that the torsion bar only bears the acting force from the core shaft and the reaction force of the end cover, and the torsion bar is prevented from directly bearing the traction force of the braid, therefore, the stress condition of the torsion bar is simple and controllable, a force limiting pin meeting the force limiting requirement can be designed according to the requirement, and the torsion bar is safe and stable in the use process. In addition, the middle section of the torsion bar is twisted, so that deformation which is uniformly distributed is easier to generate, and fracture failure caused by overhigh local stress is avoided; meanwhile, the left side and the right side bear half of the force limiting value respectively, and the diameter required by the torsion bar can be reduced. Because the material of the torsion bar needs to meet special torsion requirements, the cost is high, the manufacturing requirement is high, and the cost can be obviously saved by adopting the short torsion bar in the embodiment.

In addition, in the above embodiment of the invention, the inner tooth segments 1-3 are arranged on the through hole of the retractor frame, and the positions of the inner tooth segments 1-3 correspond to the traction direction of the mesh belt wound on the winding shaft. Compared with a structure that the through holes are provided with the internal teeth in a whole circle, the structure of the embodiment can ensure that the reel is locked at a certain position, namely the position where the internal tooth sections 1-3 are arranged, when the reel is locked.

Secondly, in the embodiment of the present invention, the force limiting pins 2-6 are disposed at both ends of the core shaft of the spool 2 as described above, when the spool 2 is in a locked state, the core shaft 2-1 tends to rotate relative to the end caps due to the pulling force from the webbing, and the force limiting pins 2-6 and the external teeth 3-1 at the middle part of the torsion bar 3 prevent the rotation. The force limiting pin 2-6 is subjected to the shearing force of the end cover and the mandrel 2-1. In the collision, the traction force of the mesh belt is subjected to a traction force loading process from small to large rapidly. In the process, when the traction force is smaller than the bearing threshold value of the force limiting pins 2-6, the traction force borne by the mandrel 2-1 is loaded on the force limiting pins 2-6, and the torsion bar 3 does not bear or mainly bears the traction force; when the traction force value is increased to exceed the bearing threshold value of the force limiting pin 2-6, the force limiting pin 2-6 is broken, the torsion bar 3 begins to completely bear the traction force of the braid transmitted by the mandrel 2-1, and then the torsion bar 3 is twisted and deformed. The force limiting pin 2-6 can adjust the force limiting threshold of the safety belt.

In the embodiment, the outer teeth at the middle part of the torsion bar 3 are provided with tooth notches, which are called avoidance tooth notches; such as the relief tooth segment 3-1-1 shown in fig. 11. FIG. 10 is a schematic diagram of a torsion bar with an outer tooth section 3-1-1 having an avoidance tooth segment at the middle part inserted into a mandrel 2-1, and the outer tooth section of the torsion bar is matched with a through hole of the mandrel. As can be seen from FIG. 10, the position of the avoidance tooth segment 3-1-1 on the torsion bar 3 is such that after the torsion bar 3 is inserted into the through hole of the spindle 2-1, the avoidance tooth segment 3-1-1 is aligned or approximately aligned with the fixing groove 2-4 on the spindle 2-1 for passing and fixing the webbing 6. The fixing groove 2-4 is a flat-long through hole which is arranged to meet the requirement that the braid passing direction is perpendicular to the central shaft of the mandrel 2-1 and needs to be as close to the central shaft as possible. The avoiding tooth gap 3-1-1 provides an avoiding space for the braid 6 to penetrate through the fixing groove 2-4, so that the braid 6 is prevented from interfering with the tooth due to the tooth arranged at the position, the braid 6 is far away from the central line of the mandrel 2-1 at the position, and the stability of the mandrel 2-1 when the braid 6 is tensioned is not facilitated.

In the embodiment of the present invention, the torsion bar 3 is further provided with an anti-dislocation tooth. As shown in fig. 5, the torsion beam 3 is provided with an anti-backlash notch 3-2b-1 at one end (the right side in the present embodiment) and is not required to be provided with the notch at the other end. Correspondingly, the concave hole on the end cover of the reel at the end needs to be provided with a matched structure. As shown in fig. 4, a corresponding error-proofing opening 2-2b-4 is provided in the recess 2-2b-3 of the end cap 2-2 b. The reason why the above-mentioned anti-rattle teeth 3-2b-1 are provided is that the torsion bar 3 must be inserted into the through hole 2-3 of the core shaft at an appropriate angle due to the presence of the above-mentioned anti-rattle teeth 3-1-1, and the anti-rattle teeth 3-2b-1 can ensure one-time success of the operation of inserting the torsion bar 3 at the time of assembly.

FIG. 6 shows the end profile of the left end portion 3-2a of the torsion beam 3 shown in FIG. 5, and FIG. 7 shows a fitting view of the left end portion 3-2a of the torsion beam 3 inserted into the recessed hole of the left end cap 2-2 a; fig. 8 is a tooth profile of the end portion of the right end portion 3-2b of the torsion beam 3 shown in fig. 5, in which the error-proof notch 3-2b-1 provided in the end portion is seen, and fig. 9 is a fitting view showing that the right end portion 3-2b of the torsion beam 3 is inserted into the concave hole of the right end cap 2-2 b.

The right end of the torsion bar 3 is provided with the mistake-proofing gap 3-2b-1, so that the tooth numbers of the left end and the right end are different, and the torsion forces borne by the two ends are not the same when the torsion bar 3 is twisted. For this reason, the present invention solves the problem in the following manner.

The outer teeth 3-1 at the middle part of the torsion bar 3 are inclined towards the right end 3-2b (namely the end part provided with the mistake-proof notch), so that the circumferential outer teeth at the middle part of the torsion bar 3 face one end provided with the mistake-proof notch 3-1 and integrally deviate. Fig. 11 and 12 show a perspective view and a sectional view of the torsion beam 3, respectively, and the inclination of the teeth 3-1-2 can be seen from fig. 11 and 12. By arranging the outer teeth 3-1 to incline towards the right, the force applied to the torsion bar 3 by the mandrel 2-1 is balanced, and the whole force is balanced.

The present invention also protects a seatbelt retractor that uses the torsion bar of the above embodiment. With regard to the technical details of the torsion bar applied to the retractor, the specific structure of the retractor can be referred to the embodiments described above for the torsion bar. The description will not be repeated here.

The invention also protects a safety belt assembly which uses the retractor of the embodiment and can obtain the beneficial effects brought by the retractor of the embodiment. The assembly of the retractor with webbing and other related accessories can be referred to the prior art and will not be discussed further herein.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto, and variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims (7)

1. A torsion bar for a safety belt retractor comprises a retractor frame and a reel, wherein the reel comprises a mandrel which is provided with a through hole along a central axis and is used for winding a braid, and two end covers which are separately arranged at two ends of the mandrel respectively; a central concave hole with internal teeth is formed in the end cover in the central position facing the inner end face of the mandrel; internal teeth are arranged at the middle section of the through hole at the axis position of the mandrel; the method is characterized in that:

the torsion bar is in a rod shape, the two end parts and the middle part of the torsion bar are respectively provided with circumferential external teeth, the external teeth at the two end parts of the torsion bar are matched with the internal teeth of the central concave hole at the end surfaces of the two end covers on the retractor, and the circumferential external teeth at the middle part of the torsion bar are matched with the internal teeth arranged at the middle section of the through hole at the central axis position of the mandrel; wherein the length of the torsion bar in the axial direction is not greater than the axial length of the spool.

2. The torsion bar for a seatbelt retractor according to claim 1, wherein the peripheral external teeth provided at a central portion of the torsion bar have an escape tooth notch.

3. The torsion beam for a seatbelt retractor according to claim 2, wherein an anti-missing tooth portion is provided at a position corresponding to the above-mentioned missing tooth portion in the circumferential direction external tooth provided at one end portion thereof.

4. The torsion bar for a seatbelt retractor according to claim 3, wherein: the outer tooth profile of the torsion bar positioned in the middle part inclines towards the end part provided with the mistake-proofing notch.

5. The torsion bar for a seatbelt retractor according to claim 2, wherein the position of the escape tooth section corresponds to a fixing groove on the spindle through which the end portion of the webbing is passed and fixed.

6. A seatbelt retractor, comprising a retractor frame, a spool, and a torsion bar for a seatbelt retractor according to any one of claims 1 to 5 above; wherein,

the retractor frame comprises two opposite side walls; circular holes with internal teeth are formed in the positions corresponding to the two side walls;

the reel comprises a mandrel and two end covers, wherein the mandrel is provided with a through hole along the central axis and is used for winding a braid, and the two end covers are detachably arranged at two ends of the mandrel respectively; the end cover is provided with external teeth along the periphery, and a central concave hole with internal teeth is arranged at the central position facing the inner end surface of the mandrel; internal teeth are arranged at the middle section of the through hole at the axis position of the mandrel;

the torsion bar penetrates through the through hole of the mandrel, and the external teeth at the middle part are meshed with the internal teeth on the inner wall of the through hole of the mandrel; two ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the scroll, and external teeth at the two ends are meshed with internal teeth of the central concave holes of the inner end surfaces of the end covers; the torsion bar has stable ductility in circumferential torsion;

in a free state, the reel is rotatably and floatingly arranged in the retractor frame, and two end covers are arranged in circular holes on two side walls of the retractor frame; when the reel is locked, the external teeth of the two end covers of the reel are meshed with the internal teeth on the frame.

7. A seatbelt assembly, wherein the seatbelt retractor according to claim 6 is used.

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