CN103847684B - For the torque arm of Webbing retractor, Webbing retractor and seat belt assembly - Google Patents

Abstract

The present invention provides a kind of torque arm for Webbing retractor, and this torque arm is shaft-like, and its both ends and middle part are provided with circumference external tooth, wherein, is positioned at the both sides bar segment of circumferential external tooth in the middle part of this torque arm effective length in the axial direction different with diameter.In one preferred version of the present invention, described torque arm is axially spaced for be docking together two sections, and the two ends of each section of torque arm are provided with circumference external tooth, and the external tooth profile of tooth of two sections of torque arm docking ends aligns；The circumferential external tooth of described two sections of torque arms docking end collectively forms the circumferential external tooth that described middle part is arranged.The torque arm of the present invention is the limit type torque arm that successively decreases, and is applied on installation band and can realize two grades of limiters of successively decreasing.The present invention also provides for a kind of Webbing retractor using described torque arm, and uses the seat belt assembly of above-mentioned Webbing retractor.

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 using the torsion bar and a safety belt assembly using the safety belt retractor.

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. Such large forces can cause the user's ribs to break off and even cause more serious injury.

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 reel is rotatably and floatingly arranged on the U-shaped frame, and the two end covers are respectively arranged in the circular hole of the U-shaped frame. In a normal state, the external teeth on the end cap are not engaged with the internal teeth of the circular hole, and the spool is rotatable in the circular hole to wind the webbing or release the webbing.

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.

The force-limiting safety device disclosed in the above-mentioned european patent document is a constant force-limiting type, also referred to as a one-stage force-limiting type or a single-stage force-limiting type, and a characteristic curve of a force-limiting value versus time is as shown in fig. 13, and is kept constant after the webbing acting force reaches a certain value. In addition to the constant force limiting safety devices described above, it is sometimes desirable to have an incremental force limiting safety device having a force limiting characteristic curve such as that of fig. 14, and a decremental force limiting safety device having a force limiting characteristic curve such as that of fig. 15. In particular, the force limiting value of the force limiting type installation device shown in fig. 15 is gradually reduced in the collision process, and under many collision modes, the force limiting characteristic can obtain better protection effect. Therefore, there is a need for a safety belt and components thereof having a decreasing force limiting characteristic curve based on the constant force limiting safety device. There is no prior art teaching of retrofitting the aforementioned prior art harness to a tapered force-limiting safety device.

Disclosure of Invention

The invention provides a torsion bar for a safety belt, which is a degressive force limiting torsion bar and can realize secondary degressive force limiting when being applied to a mounting belt. The present invention additionally provides a retractor and a seatbelt assembly using the torsion bar.

The torsion bar for the safety belt retractor is in a bar shape, two end parts and the middle part of the torsion bar are respectively provided with the circumferential external teeth, and the two side bar sections of the circumferential external teeth in the middle of the torsion bar are different in effective length in the axial direction.

Optionally, the retractor comprises a retractor frame and a spool, wherein the spool comprises a spindle and an end cover; the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; a central concave hole with internal teeth is formed in the end cover towards the central position of the inner end surface side of the mandrel;

the length of the torsion bar in the axial direction is not greater than the axial length of the reel; the circumferential external teeth at the two end parts of the torsion bar are matched with the internal teeth of the central concave hole on the inner end surface side 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 in the through hole of the mandrel; the effective length of the rod sections on the two sides of the circumferential external teeth arranged in the middle of the torsion bar is different in the axial direction.

Optionally, the torsion bar is divided into two sections which are butted together in the axial direction, two ends of each section of the torsion bar are provided with circumferential external teeth, and the external teeth at the butted end parts of the two sections of the torsion bar are aligned in tooth form; the circumferential external teeth at the butt joint end parts of the two sections of torsion bars jointly form the circumferential external teeth arranged at the middle part.

Optionally, the two sections of the torsion bar have different diameters and/or different materials.

Optionally, the circumferential outer teeth of the two sections of butted end portions of the torsion bar are provided with avoidance missing teeth, and the two avoidance missing teeth are in the same position and correspond to the fixing groove which penetrates through the mandrel and fixes the end portion of the mesh belt.

Optionally, the retractor comprises a retractor frame and a spool, wherein the spool comprises a spindle and an end cover; the mandrel is used for winding the braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; a through hole with internal teeth is formed in the center of the end cover;

the length of the torsion bar in the axial direction is greater than that of the reel; the circumference external tooth setting of its both ends with the end cover looks intercrossing position and cooperate with the internal tooth of both ends lid through-hole on the coiler, the circumference external tooth that is located the torsion bar middle part with the internal tooth that sets up in the through-hole of dabber cooperatees.

In addition, the present invention provides a seatbelt retractor including a retractor frame, a spool, and the torsion bar described in any one of the above 2 to 5; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; 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 side of the mandrel;

the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged in the middle of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two outer ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the reel, and the circumferential outer teeth of the two outer ends are meshed with the inner teeth of the central concave holes on the inner end surface sides 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.

Further, the present invention provides a seatbelt retractor including a retractor frame, a spool, and the torsion bar described in the above item 6; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; the outer teeth are arranged on the periphery of the end cover, and a through hole with inner teeth is formed in the center of the end cover;

the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged in the middle of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two end parts of the torsion bar respectively penetrate through the central through holes of the two end covers of the reel, and the circumferential external teeth of the two end parts are meshed with the internal teeth of the central through hole of the end cover; 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.

In addition, the invention also provides a safety belt assembly using the safety belt retractor.

Compared with the prior art, the torsion bar for the safety belt retractor, which is provided by the invention, has the advantages that the effective lengths of the bar sections on the two sides of the peripheral external teeth at the middle part of the torsion bar in the axial direction are different, after the torsion bar is applied to a safety belt, when a mandrel rotates, the bar section with the shorter effective length is firstly broken and fails due to larger deformation, and the process causes the force limiting value of the torsion bar to obviously change. Before this failure occurs, the torsion bar resists the webbing tension over its full effective length, and so the force limit is relatively high, at which stage the first level of force limit shown in fig. 15 is achieved, which is a higher force limit; after the failure occurs, the mandrel continues to rotate under the pulling of the braid until the rod section with the longer effective length is broken after the number of broken rotation turns is reached, and the second stage limiting force with the lower limiting force value shown in fig. 15 is realized at the stage; at this stage, the force limit is small because the shorter effective length bar segment has already broken and only the unbroken bar segment is carrying the webbing tension. In the process, the safety belt realizes the effect of degressive force limitation in the collision process, and can protect the safety belt user more effectively.

In addition, in the optional technical scheme of the torsion bar, the torsion bar is divided into two coaxial sections; the two torsion bar sections with the same diameter or different diameters are combined for use, and a plurality of torsion values can be combined, so that a retractor with a plurality of limit values can be formed, and different requirements of different automobile manufacturers on the limit values of the safety belt can be met; moreover, because the torsion bar is made of special materials and processed by a cold heading process, a separate die is required for each diameter of the torsion bar, and the manufacturing equipment and the die are very expensive; by adopting the two-section type torsion bar, the torsion bar sections processed by using fewer processing dies can be realized, and a plurality of required limit values can be obtained in a combined mode, so that the die opening quantity can be reduced, and the manufacturing cost is further saved.

Further, in a preferred embodiment of the present invention, both ends of the torsion beam are disposed at both end caps of the spool without passing through the end caps, and the torsion beam is shortened in length relative to the torsion beam of the related art; the torsion bar is not easy to bend and deform and is not restrained by other parts except the end covers at the two sides, the integral stress condition of the torsion bar is simplified, and the use process is safer and more stable; moreover, 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 special torsion requirements, the cost is high, the manufacturing requirement is high, the shorter length of the torsion bar can save the cost, and the manufacturing difficulty is reduced.

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 view of a first segment of a first embodiment of a torsion bar of the present invention;

FIG. 6 shows the end profile of the left end of the first section of the torsion bar shown in 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 a cross-sectional tooth profile of the torsion bar shown in FIG. 5;

FIG. 9 shows a schematic view of a central section of the torsion bar after insertion into the mandrel;

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 is a cross-sectional view of a two-piece torsion bar of an embodiment of the present invention as it is assembled with other spool components at different diameters;

fig. 12 is a schematic view of a torsion beam according to a second embodiment of the present invention;

FIG. 13 is a graph of force limiting versus time characteristic of a constant force limiting safety device;

FIG. 14 is a graph of force limiting value versus time for an incremental force limiting safety device;

FIG. 15 is a graph of force limiting value versus time for a decreasing force limiting safety device.

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.

First embodiment

In this embodiment, the torsion bar is a rod shape, and the torsion bar is divided into two sections in the axial direction. Referring to fig. 5, which is a schematic structural view of one of the first embodiment of the torsion bar of the present invention, the torsion bar section 3a has external teeth 3-2a and external teeth 3-2b at two ends. When the two sections of torsion bar groups are integrated, two ends of the two sections of torsion bars are butted together, the end surfaces are butted, and external teeth at the opposite ends are aligned without staggering teeth to form the integrated torsion bar. External teeth at two outer end parts of the torsion bar are matched with internal teeth of central concave holes on end surfaces of two end covers on the retractor (the matching relationship of the torsion bar and the retractor is described in detail in the following description), and circumferential external teeth at two abutting end parts of the torsion bar are matched with internal teeth arranged in a through hole of the mandrel; and the length of the torsion bar in the axial direction is not more than the axial length of the coiler scroll.

In this embodiment, the two segments of the torsion bar have different effective lengths in the axial direction. The effective length refers to the axial length of the torsion bar or the bar section except for the shaft section with the external teeth at the two ends removed. The different effective lengths are deliberately designed in the torsion bar design and are not due to manufacturing tolerances. In the description of the present embodiment, the torque rod refers to a whole composed of two segments, unless it is explicitly stated that the torque rod is a segment of the torque rod.

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 seat belt of the present invention, the retractor includes a retractor frame 1, a reel 2, and a torsion bar 3 (including a first section 3a and a second section 3b, as shown in fig. 4) according to the present embodiment

With continued reference to fig. 1, the retractor frame 1 is U-shaped, and includes two opposite sidewalls: 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 inner tooth sections 1-3 are respectively arranged at the same positions on the two through holes (only the inner tooth sections arranged on the second through hole 1-2a are marked in fig. 1). 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 peripheries of the two end covers are both provided with external teeth, as shown in fig. 4, the periphery of the left end cover 2-2a is provided with the external teeth 2-2a-1, the periphery of the right end cover 2-2b is provided with the external gear ring 2-2b-1, and the teeth on the two end covers are both one-way teeth and face the rotating direction of the mandrel 2-1 when the braid is released. The outer teeth of the peripheries of the two end covers are matched with the inner tooth sections of the two through holes on the frame 1.

Pin holes, such as the pin hole 2-2b-2 on the right-hand end cap 2-2b shown in fig. 4, are also provided at positions corresponding to the force limiting pins on the end face sides (referred to as inner end face sides) of the end caps 2-1. When both end caps are provided on both end faces of the spindle 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 central positions of the inner end surface sides 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 a sensing element forming the safety belt assembly, and the periphery of the right side projecting shaft 2-2b-5 is provided with teeth which are connected with a coil spring forming the safety belt assembly.

In the case of using the torsion bar of the present embodiment in a retractor reel, the torsion bar 3 (including the first section 3a and the second section 3b) and the reel 2 are constructed 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 external teeth of the butt end portions of the two axial sections thereof are engaged with the internal 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.

In this embodiment, as shown in fig. 4, a wear-reducing ring (not shown) is further disposed between the bosses of the two end caps and the spigot of the mandrel 2-1. The friction reducing ring (not shown) is generally made of low-friction plastic, and can provide transition for the spigot position matched 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.

As shown in fig. 4, an annular boss (an annular boss 2-2b-6 on the right-side end cover shown in fig. 4) is arranged on the outer edge of the inner side of the end cover, and an avoiding spigot matched with the annular boss is arranged at the corresponding position of 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 collision happens, 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.

In the embodiment, because the length of the torsion bar is shortened, and the boss at the inner side of the end cover and the spigot of the mandrel are arranged, the torsion bar only bears the acting force from the mandrel and the reaction force of the end cover, and the torsion bar is prevented from directly bearing the traction force of the braid, 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 this embodiment, the provision of the torsion beam in two separate segments has the following effects: can use the torsion bar section combination of two the same diameters or different diameters, can make up out a plurality of limit values to can adopt less torsion bar to form the coiler that has a plurality of limit values, satisfy different automobile manufacturer to the different requirements of safety belt limit value. Fig. 11 shows a schematic view of a torsion bar with a different diameter torsion bar segment group. In addition, torsion bars of the same material or different materials can be used in combination, and different force limiting effects can be obtained similarly.

In the embodiment, the torsion bar is arranged into two separate sections, the effective lengths and the diameters of the two sections are different, and when the mandrel rotates, the torsion bar section with the shorter effective length is firstly broken and fails due to the large number of rotation turns, so that the first-stage force limiting is realized; and then the mandrel continues to rotate, and because the torsion bar section with shorter effective length is broken, the tension of the braid can be borne only by the torsion bar section with longer effective length, so that the force limit value of the torsion bar is obviously reduced, namely the torsion bar enters a second-stage force limit with smaller force limit value. That is, in the present embodiment, two-stage decreasing force limitation is realized by setting the effective lengths of the two sections of the torsion bar to be different. This mode of operation provides more effective protection for the seat belt user.

In addition, since the torsion bar is made of a special material and is manufactured through a cold heading process, a separate mold is required for each diameter of the torsion bar, and manufacturing equipment and molds thereof are expensive. By adopting the two-section type torsion bar of the embodiment, the torsion bar with a plurality of limit values can be combined by the torsion bar sections processed by the limited processing die, so that the die sinking quantity can be reduced, and the manufacturing cost can be saved. And the torsion bar with a shorter size is more convenient to process, the processing yield is higher, and the cost of each die is relatively lower.

In addition, varying the effective length, material, and varying the diameter of the torsion bar segments can be used simultaneously to combine more variations. And will not be described in detail herein.

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; as shown in fig. 5, the avoidance tooth segment 3a-2-1 on the right side of the first segment 3 a. FIG. 10 is a schematic diagram of a torsion bar with an outer tooth portion having an avoidance tooth segment 3a-2-1 at the middle part inserted into a mandrel 2-1, wherein the outer tooth portion 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 3a-2-1 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.

FIG. 6 shows the end profile of the left end 3a-1 of the first section 3a of the torsion beam shown in FIG. 5, and FIG. 7 shows a mating view of the left end 3a-1 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 3a-2 of the first section 3a of the torsion beam shown in fig. 5, in which the escape tooth segment 3a-2-1 provided at the end portion can be seen, and fig. 9 is a fitting view showing the right end portion 3a-2 of the torsion beam 3 inserted into the concave hole of the core shaft 2-1.

Second embodiment

Please refer to fig. 12, which is a schematic diagram of a torsion bar according to a second embodiment of the present invention. In the present embodiment, the torsion beam is of a single-piece type, and is also provided with external circumferential teeth (external teeth 3-2, external teeth 303, and external teeth 3-1) at both end portions and at a central portion thereof, wherein the effective lengths in the axial direction of the two side beam segments 3a and 3b of the external circumferential teeth 3-1 at the central portion of the torsion beam are different. Other aspects of the structure of the torsion beam of the present embodiment and the fitting relationship with the seat belt retractor are the same as those of the first embodiment, and the technical effects of the torsion beam of the present embodiment are the same as those of the first embodiment, and will not be described again.

In addition, the length of the torsion bar in the axial direction of the torsion bar may be greater than the axial length of the spool, and when the torsion bar is applied to a seat belt retractor, the central concave holes of the two end covers of the spool are provided with through holes with internal teeth, and the torsion bar crosses the two end covers and extends out of the end covers through the through holes. Circumferential external teeth matched with the internal teeth of the through hole are arranged at the positions, close to the two end parts, of the torsion bar and crossed with the end covers; the portion of the torsion bar extending beyond the end cap is connected to the coil spring and the sensing element, respectively. Otherwise, the torsion beam in this embodiment is otherwise the same as the first and second embodiments described above, for example, the effective length and diameter in the axial direction of the both side beam segments of the circumferential external teeth in the middle portion of the torsion beam are different. The description of the torsion bar will not be repeated here.

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 (6)

1. A safety belt retractor is characterized by comprising a retractor frame, a reel and a torsion bar; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; 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 side of the mandrel;

the torsion bar is rod-shaped; the torsion bar is divided into two sections which are butted together in the axial direction and have different effective lengths in the axial direction, and two ends of each section of the torsion bar are provided with circumferential external teeth; the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged in the middle of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two outer ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the reel, and the circumferential outer teeth of the two outer ends are meshed with the inner teeth of the central concave holes on the inner end surface sides 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.

2. A safety belt retractor is characterized by comprising a retractor frame, a reel and a torsion bar; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; 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 side of the mandrel;

the torsion bar is rod-shaped; the torsion bar is divided into two sections which are butted together in the axial direction and have different effective lengths in the axial direction, and two ends of each section of the torsion bar are provided with circumferential external teeth; the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged at two inner ends of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two outer ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the reel, and the circumferential outer teeth of the two outer ends are meshed with the inner teeth of the central concave holes on the inner end surface sides 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.

3. A safety belt retractor is characterized by comprising a retractor frame, a reel and a torsion bar; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; 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 side of the mandrel;

the torsion bar is rod-shaped; the torsion bar is divided into two sections which are butted together in the axial direction and have different effective lengths in the axial direction, and two ends of each section of the torsion bar are provided with circumferential external teeth; the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged in the middle of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two outer ends of the torsion bar are respectively inserted into the central concave holes of the two end covers of the reel, and the circumferential outer teeth of the two outer ends are meshed with the inner teeth of the central concave holes on the inner end surface sides of the end covers; avoiding missing teeth are arranged on circumferential external teeth of two sections of butted end parts of the torsion bar, and the two avoiding missing teeth are in the same position and correspond to a fixing groove which penetrates through the mandrel and fixes the end part of the mesh belt together; 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.

4. A safety belt retractor is characterized by comprising a retractor frame, a reel and a torsion bar; 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 an end cover, the mandrel is used for winding a safety belt braid, and a through hole with a whole circle of internal teeth is formed along the central axis of the mandrel; the number of the end covers is two, and the end covers are respectively arranged at two ends of the mandrel in a separable mode; the outer teeth are arranged on the periphery of the end cover, and a through hole with inner teeth is formed in the center of the end cover;

the torsion bar is in a rod shape, and circumferential external teeth are arranged at the two end parts and the middle part of the torsion bar; the torsion bar is divided into two sections which are butted together in the axial direction and have different effective lengths in the axial direction; the length of the torsion bar in the axial direction is greater than that of the reel in the axial direction; the torsion bar penetrates through the through hole of the mandrel, and circumferential external teeth arranged at two inner ends of the torsion bar are meshed with internal teeth on the inner wall of the through hole of the mandrel; the two end parts of the torsion bar respectively penetrate through the central through holes of the two end covers of the reel, and the circumferential external teeth of the two end parts are meshed with the internal teeth of the central through hole of the end cover; 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.

5. A seatbelt assembly, wherein the seatbelt retractor according to any one of claims 1 to 3 is used.

6. A seatbelt assembly, wherein the seatbelt retractor according to claim 4 is used.