CN106143403B

CN106143403B - Force-limiting retractor

Info

Publication number: CN106143403B
Application number: CN201510154416.3A
Authority: CN
Inventors: 伏春波
Original assignee: Trw Automotive Research & Development Shanghai Co ltd
Current assignee: Trw Automotive Research & Development Shanghai Co ltd
Priority date: 2015-04-03
Filing date: 2015-04-03
Publication date: 2020-07-28
Anticipated expiration: 2035-04-03
Also published as: CN106143403A

Abstract

The invention relates to a force-limiting retractor, which comprises a coil spring assembly, a force-limiting rod, a belt winding drum, a stop wheel, a U-shaped frame assembly and a mechanical side cover, wherein: the force-limiting retractor also comprises a detachable force-limiting component which is detachably arranged on the belt winding drum and rotates along with the belt winding drum to form a rotating path; the stop wheel is provided with a stop component which is arranged on the rotation path of the force limiting component; and the force limiting member is selectively engageable with the stop member to provide a force limiting action during rotation of the take-up spool relative to the stop wheel. The invention integrates the functions of a common force-limiting retractor, an incremental force-limiting retractor and a decreasing force-limiting retractor, effectively reduces the design and development cost, and does not need to design a special retractor structure and mechanism aiming at the independent force-limiting function. Meanwhile, the structure is more compact, the structure of the part is simple, the size is reduced compared with the traditional design, the size chain superposition is reduced, and the quality risk is reduced.

Description

Force-limiting retractor

Technical Field

The present invention relates to a force-limiting retractor for a vehicle seat belt having a force-limiting function.

Background

With the increasing amount of motor vehicles in China, many motor vehicle users put higher demands on the dynamic property and the economical efficiency of the vehicle, and meanwhile, the vehicle is required to have good safety. The safety strategies of vehicles are mainly divided into active safety and passive safety, in which the safety belt is one of the most important components. The use of the safety belt effectively saves about 45 percent of lives in traffic accidents, and 67 percent of people are prevented from being seriously injured. When the motor vehicle collides, the impact force of the common safety belt on the chest of a passenger can reach 11KN or higher, the chest compression amount of the passenger is larger, and the passenger is easily damaged greatly. Therefore, passive safety products, such as a latch, a buckle, a force limiting retractor, etc., having an energy absorbing effect, which can reduce the impact of the webbing on the occupant, have been developed on the basis of the general seat belt.

In the existing design, the structure of the force limiting retractor is complex. Some force limiting retractors are gradually increased or decreased in a mode that the blade cuts off materials on the belt winding drum, but in the process of cutting off the materials, the belt winding drum is generally manufactured by a die-casting process, so if the inside of the die-casting material has the defect of air holes and equal pressure casting, a characteristic curve is affected, and the force limiting performance of the force limiting retractor is unstable. Further, since the cutter generates an axial force during the cutting of the material, an assembly for fixing the stopping wheel and the take-up reel needs to be added, which increases the assembly cost and complicates the structure.

Disclosure of Invention

Therefore, the invention aims to provide a force-limiting retractor for a vehicle safety belt, which overcomes the defects, adopts a force-limiting steel wire structure or a carbon steel strip structure, simultaneously realizes common force limitation, incremental force limitation and incremental force limitation, and reduces the force limitation, and the structures of the force-limiting steel wire and the steel strip do not generate component force in the axial direction, reduces the number of parts, makes the structure more compact and exquisite, reduces the volume of the retractor, and reduces the weight of the retractor. The cost is reduced.

It is another object of the present invention to provide a force limiting retractor for a vehicle seat belt that includes the functionality of a conventional force limiting retractor, a step-down force limiting retractor and an incremental force limiting retractor.

In order to achieve the above object, in one aspect, the present invention provides a force limiting retractor for a seat belt of a vehicle, the force limiting retractor including a coil spring assembly, a force limiting lever, a spool, a detent wheel, a U-shaped frame assembly, and a machine side cover, wherein:

the force-limiting retractor further comprises a detachable force-limiting member which is detachably mounted on the belt winding drum and can rotate along with the belt winding drum to form a rotating path;

the stopping wheel is provided with a stopping component which is arranged on the rotation path of the force limiting component; and is

The force limiting member is selectively engageable with the stop member to provide a force limiting action during rotation of the take-up spool relative to the stop wheel.

In one embodiment, the force limiting member is not engaged with the stop member when the take-up drum starts to rotate relative to the stop wheel, and the force limiting member is engaged with the stop member after the take-up drum rotates relative to the stop wheel by a predetermined angle.

In one embodiment, the force limiting member engages the stop member when the spool begins to rotate relative to the stop wheel, and disengages the force limiting member after the spool has rotated a predetermined angle relative to the stop wheel.

In one embodiment, the predetermined angle is dependent on a length of the force limiting member.

In one embodiment, the force limiting member is in the form of a force limiting steel wire or a force limiting steel strip.

In one embodiment, the force-limiting steel wire or the force-limiting steel strip has a holding section at one end, by means of which the force-limiting steel wire or the force-limiting steel strip is detachably held to the take-up reel.

In one embodiment, the retaining portion is in the form of a ferrule.

In one embodiment, the other end of the force limiting steel wire or strip is a free end.

In one embodiment, the force limiting steel wire or strip further comprises a variable engagement portion engageable with the stop member to provide a force limiting action.

In one embodiment, a holding member is provided on the take-up drum, and the holding portion is detachably held to the holding member.

The force limiting retractor can effectively reduce the injury to the passenger (or the test dummy) in the process of vehicle collision, the force limiting value is gradually increased along with the displacement of the passenger (or the test dummy) in the collision process, the displacement of the passenger (or the test dummy) is reduced, and the secondary collision between the passenger (or the test dummy) and the vehicle interior object is reduced. Moreover, the force-limiting retractor has the advantages of cost saving, compact and exquisite structure, stable performance, reduced volume, reduced weight, reduced component number and easy assembly.

Drawings

Various objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings. In the drawings, like reference characters designate the same or similar parts throughout the different views.

Fig. 1 is a characteristic curve diagram of a conventional force-limiting retractor.

Figure 2 is a graph of the characteristics of a step-down force limited retractor.

Figure 3 is a graph of the behaviour of an incremental force limiting retractor.

Figure 4 is an exploded view of components of a limited force retractor according to the present invention.

Figure 5 is a front view of a take-up drum of an incremental force-limiting retractor.

Fig. 6 is a schematic view showing the force limiting member of the incremental force limiting retractor in an initial position.

Fig. 7 is a schematic view showing the force limiting member of the incremental force limiting retractor in an intermediate position.

Fig. 8 is a schematic view showing the force limiting member of the incremental force limiting retractor in an intermediate position.

Fig. 9 is a schematic view showing deformation of a force limiting member of the incremental force limiting retractor.

Figure 10 is a front view of the take-up drum of the step-down, force limited retractor.

Fig. 11 is a schematic view showing the force limiting member of the step-down force limiting retractor in an initial position.

Fig. 12 is a schematic view showing deformation of the force limiting member of the step-down force limiting retractor.

Figure 13 is a perspective view of the take-up drum of the force limiting retractor.

Fig. 14 is a perspective view of a detent wheel of the force limiting retractor.

List of reference numerals:

1 coil spring assembly

2 force limiting rod

3 winding drum

4 force limiting component

5 stopping wheel

6 locking claw

7 area feels subassembly

8 reset spring

9 mechanical side cover

10 vehicle sensing assembly

11U type frame subassembly

36 holding member

41 holding part

42 variable joint part

51 stop member

Detailed Description

An embodiment of a force limiting retractor according to the present invention will be described below with reference to the accompanying drawings. The description and drawings are merely exemplary in nature and are provided to enable one skilled in the art to make and use the described limited force retractor and are not intended to limit the scope of the appended claims in any way.

The terms "comprising," "including," and "having," as used herein, are intended to be inclusive and mean that there may be additional elements other than the listed elements. The term "retractor" refers to a device for fully or partially retracting a belt webbing. The term "belt drum" refers to the tubular component of the retractor used to wind the webbing. The term "coil spring assembly" refers to the means on the retractor for providing the torque force. The term "wrap spring" refers to a leaf spring coiled in a wrap spring assembly having a hook centrally attached to a spool for transmitting torque. The term "coil spring seat" refers to an assembly for securing a coil spring to a retractor, the spring plate and the coil spring seat typically being disposed in a coil spring outer cover. The term "frame" refers to the assembly on the retractor for supporting other components. The term "retractor locking" means that the spool comes into contact with the frame as the webbing moves under the force of the webbing, thereby preventing the webbing from continuing to be pulled out. When the locking is not taking place, the winding reel and the frame are not in contact with each other. The term "force limiting retractor" refers to a retractor that reduces the level of occupant injury during a crash.

Force limiting retractors are a common energy absorbing device for safety belts. The force limiting rod capable of absorbing energy is arranged in the common force limiting retractor, when the load reaches a preset load value, the force limiting rod is subjected to torsional deformation, a certain length of braid is released in the twisting process, and partial shoulder strap force is absorbed, so that the force limiting function of the safety belt is realized.

The shoulder belt force-time (F-t) characteristic curve given by a common force limiting retractor is shown in fig. 1, and in the process of vehicle collision, after the stress of the force limiting retractor reaches a certain force value, a force limiting rod in the force limiting retractor starts to generate torsional deformation to absorb a part of energy.

An F-t characteristic curve given by the decreasing type force limiting retractor is shown in fig. 2, and in the process of vehicle collision, after the stress of the force limiting retractor reaches a certain force value, a force limiting rod in the force limiting retractor starts to generate torsional deformation to absorb a part of energy. Along with the increase of the displacement of test dummy, also can produce certain effort to the dummy after the gasbag starting point explodes, the curve of limit force coiler takes place certain falling this moment, can not cause bigger injury to the human body after the power value stack that limit force coiler and gasbag expanded like this.

An F-t characteristic curve given by the incremental force limiting retractor is shown in fig. 3, and in the process of vehicle collision, after the stress of the force limiting retractor reaches a certain force value, a force limiting rod in the force limiting retractor starts to generate torsional deformation to absorb a part of energy. Along with the increase of the displacement of the dummy for testing, if the weight of a passenger wearing the safety belt is light, the inertia of the passenger is not enough to enable the force limiting value of the force limiting retractor to be large, and the common force limiting retractor can effectively protect the passenger; if the passenger wearing the safety belt has heavy weight and large inertia, the generated displacement will be larger, and the force value of the ordinary force limiting retractor is increased less (as shown in fig. 1), so that the passenger cannot be restrained effectively, while the force value of the incremental force limiting retractor is increased more, so that the passenger with heavy weight can be restrained effectively. That is, the incremental force limiter retractor will provide a further increased force limit when the amount of webbing pulled out reaches a certain value.

Referring to fig. 4, there is shown an exploded perspective view of a force limiting retractor according to the present invention. The force limiting retractor according to the present invention includes a coil spring assembly 1, a force limiting lever 2, a spool 3, a stopping wheel 5, a U-shaped frame assembly 11, and a machine side cover 9.

The belt drum 3, the stop wheel 5 and the force-limiting lever 2 are the main force-limiting functional components of the force-limiting retractor. The realization of the limit force function of the limit force coiler mainly passes through: the flower-shaped teeth at one end of the force limiting rod 2 are meshed with the flower-shaped teeth at the inner side of the tape winding cylinder 3, the flower-shaped teeth at the other end are meshed with the flower-shaped teeth at the inner side of the stop wheel 5, and after assembly, the tape winding cylinder 3 and the stop wheel 5 are fixed together through a certain connecting structure.

In a general seatbelt, a spool of a retractor is integrated with a stopper wheel. According to the present invention, in the force-limited type seatbelt, as shown in fig. 4, the spool 3 of the retractor is separated from the detent wheel 5. However, whether the ordinary safety belt or the force-limiting safety belt is adopted, the belt sensing assembly is required to be assembled on the stopping wheel, and the assembly sequence is as follows: firstly, a locking claw 6 is arranged on a stop wheel 5, then a belt sensing component 7 is arranged in the locking claw, and finally a return spring 8 is arranged.

In the force-limiting type seatbelt, a force-limiting rod 2 capable of absorbing energy is installed in a spool 3. When the force-limiting retractor is activated, the locking pawl 6 mounted on the detent wheel 5 is locked in meshing engagement with the teeth of the U-shaped frame assembly 11 under the triggering of any one of the belt feel, vehicle feel (e.g., via the belt feel assembly 7, the vehicle feel assembly 10) or angular tilt feel, thereby bringing the detent wheel 5 to a standstill so as not to rotate with the spool 3. The take-up reel 3 is subjected to a torque action during the continued pulling of the webbing. When the load reaches a preset load value, the force limiting rod 2 is subjected to torsional deformation, a certain length of woven belt is released in the twisting process, and partial impact force generated to a human body by the safety belt in the collision process is absorbed, so that the force limiting function of the safety belt is realized. The shoulder strap force-time (F-t) characteristic of this process is shown in fig. 1.

With continued reference to fig. 4, in a preferred embodiment of the invention, the force limiter retractor further comprises a detachable force limiting member 4, which force limiting member 4 can be detachably mounted on the spool 3 to rotate with the spool 3, whereby the force limiting member 4 forms a rotational path.

The stop wheel 5 has a stop member 51 thereon, which stop member 51 is preferably in the form of a stop pin, as shown in fig. 14. Of course, the stop member may take any other suitable form as will occur to those of skill in the art. The stopper member 51 is provided on a rotation path of the force limiting member 4 so as to contact and interact with the force limiting member 4 to form a force limiting action, if necessary.

After the locking function is triggered, the stopping wheel 5 and the stopping member 51 thereon stop rotating, whereby the spool 3 rotates relative to the stopping wheel 5 under the pulling action of the webbing. During rotation of the spool 3 relative to the stop wheel 5, the force limiting member 4 can selectively engage with the stop member 51 on the stop wheel 5 to form a force limiting effect.

Specifically, with the incremental force-limiting retractor, in the first stage, when the spool 3 starts to rotate relative to the stopper wheel 5, the force-limiting member 4 does not engage with the stopper member 51. In the second stage, after the spool 3 is rotated by a predetermined angle with respect to the stopping wheel 5, the force limiting member 4 is engaged with the stopping member 51. In this way, in the first phase, the force limiting action is produced solely by the force limiting lever 2 itself, while the force limiting member 4 is not active, the force limiting curve being in the region of the first half of fig. 3. In the second phase, the force-limiting member 4 interacts with the stop member 51 to produce a force-limiting effect, whereby the force-limiting effects of the force-limiting rod 2 on the force-limiting member 4 are superimposed on one another to produce a greater force-limiting effect, the force-limiting curve being in the range of the second half of fig. 3.

Whereas for a step-down force-limiting retractor, in a first phase, when the spool 3 starts to rotate relative to the stop wheel 5, the force-limiting member 4 engages with the stop member 51. In the second stage, after the spool 3 is rotated by a predetermined angle with respect to the stopping wheel 5, the force limiting member 4 is disengaged from the stopping member 51. In the first phase, the force-limiting member 4 interacts with the stop member 51 to produce a force-limiting effect, whereby the force-limiting effects of the force-limiting rod 2 on the force-limiting member 4 are superimposed on one another to produce a greater force-limiting effect, the force-limiting curve being in the range of the first half of fig. 2. In the second phase, the force-limiting action is produced solely by the force-limiting lever 2 itself, while the force-limiting member 4 is inactive, the force-limiting curve being in the range of the second half of fig. 2.

Preferably, the force limiting member 4 may be in the form of a force limiting steel wire or a force limiting steel strip, the cross-section of which may be of any suitable shape, such as square, circular, trapezoidal, diamond-shaped, or oval, etc. The force-limiting steel wire or strip may be made of any suitable material, such as carbon steel.

The force-limiting steel wire or the force-limiting steel strip has a holding portion 41 at one end, and the take-up reel 3 may have a holding member 36 thereon, and the holding member 36 may be in the form of a protrusion, as shown in fig. 13. The holding portion 41 is held to the holding member 36. The retaining portion 41 may preferably be in the form of a ferrule that fits over the retaining member 36. The ferrule may have any suitable shape, such as square, circular, trapezoidal, or oval, among others.

The other end of the force-limiting steel wire or strip is a free end with a variable engaging portion 42 between the free end and the holding portion 41. The force limiting steel wire or strip interacts with the stop member 51 through the variable engagement portion 42.

The variable engagement portion 42 may have any suitable shape, such as square, circular, trapezoidal, diamond, or oval, among others.

The force-limiting retractor can integrate the functions of a common force-limiting retractor, an incremental force-limiting retractor and a decremental force-limiting retractor. When the force limiting component 4 is not installed, the force limiting retractor is an ordinary force limiting retractor. And when the force limiting member 4 is installed, the force limiting retractor may be an incremental force limiting retractor or a decremental force limiting retractor.

Reference is made to fig. 5-9, which are schematic illustrations of an incremental force limiting retractor. For the incremental force limiting function, the initial position is shown in fig. 6, the variable engaging part 42 of the force limiting member 4 is away from the stop member 51 on the stop wheel 5, after the locking function is triggered, the stop wheel 5 and the stop member 51 thereon stop rotating, the belt drum 3 continues to rotate counterclockwise under the pulling of the webbing, the force limiting member 4 is fixed on the belt drum 3, and the force limiting member 4 rotates along with the belt drum 3. Fig. 7 and 8 are middle processes of rotation, in fig. 8, the force limiting member 4 is close to the stop member 51, only the force limiting rod of the force limiting retractor is torsionally deformed before the force limiting member 4 is close to the stop member 51, the torsional curve of the force limiting retractor is in the first half section shown in fig. 3, after the force limiting member 4 contacts the stop member 51, the force limiting member 4 is blocked by the stop member 51 to rotate under the driving of the belt winding drum 3, the force limiting member 4 is forced to deform and deform, and the force value curve of the force limiting retractor is in the second half section shown in fig. 3. Fig. 9 shows the force-limiting member 4 deformed by the take-up reel 3.

Reference is made to fig. 10-12, which are schematic illustrations of a step-down, force-limited retractor. For the decreasing force limit, the initial position is as shown in fig. 11, the variable engaging part 42 of the force limit member 4 faces the stop member 51 on the stop wheel 5, after the locking function is triggered, the stop wheel and the stop member 51 thereon stop rotating, the spool 3 continues to rotate counterclockwise by the pulling of the webbing, the force limit member 4 is fixed on the spool 3, and the force limit member 4 rotates along with the spool 3. For decreasing force limitation, the force limiting member 4 contacts the stop member 51 at the initial position, and is stopped by the stop member 51 to rotate, and the force limiting member 4 is forced to deform and deform under the driving of the belt winding drum 3, and the force value curve of the force limiting retractor is shown in the first half of fig. 2. When the torsion deformation of the force limiting member 4 is finished, the acting force of the force limiting member 4 is finished, only the force limiting rod acts on the whole force limiting retractor, and the force limiting curve is shown as the second half section in fig. 2.

As can be seen from the above description, the range in which the force-limiting member 4 acts to generate the force-limiting action corresponds to the relative angle by which the spool 3 rotates with respect to the detent wheel 5 (e.g., the above-mentioned predetermined angle, which corresponds to the difference of 360 degrees from the relative angle for an incremental force-limiting retractor, and which corresponds to the relative angle for a decremental force-limiting retractor) depends on the length of the force-limiting member 4, i.e., the length of the force-limiting wire or the force-limiting steel belt.

The invention integrates the functions of a common force-limiting retractor, an incremental force-limiting retractor and a decreasing force-limiting retractor, effectively reduces the design and development cost, and does not need to design a special retractor structure and mechanism aiming at the independent force-limiting function. Meanwhile, the structure is more compact, the structure of the part is simple, the size is reduced compared with the traditional design, the size chain superposition is reduced, and the quality risk is reduced.

Although the present invention has been disclosed with reference to certain embodiments, numerous variations, modifications, and changes may be made to the described embodiments without departing from the scope and ambit of the present invention. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is to be accorded the full scope defined by the language of the following claims and equivalents thereof.

Claims

1. A force limiting retractor for a seat belt of a vehicle, the force limiting retractor comprising a coil spring assembly, a force limiting lever, a spool, a detent wheel, a U-shaped frame assembly, and a machine side cover, wherein:

The force limiting member is selectively engageable and interactable with the stop member to provide a force limiting action during rotation of the take-up spool relative to the stop wheel.

2. The limited force retractor as set forth in claim 1, wherein the force limiting member is not engaged with the stop member when the spool starts to rotate relative to the stop wheel, the force limiting member being engaged with the stop member after the spool rotates relative to the stop wheel by a predetermined angle.

3. The limited force retractor as set forth in claim 1, wherein the force limiting member engages the stop member when the spool begins to rotate relative to the stop wheel, and wherein the force limiting member disengages the stop member after the spool rotates a predetermined angle relative to the stop wheel.

4. The force limiting retractor according to claim 2 or 3 wherein the predetermined angle depends on a length of the force limiting member.

5. The force limiting retractor as claimed in any one of claims 1 to 3, wherein the force limiting member is in the form of a force limiting steel wire or a force limiting steel belt.

6. The force limiting retractor as claimed in claim 5, wherein the force limiting wire or the force limiting steel belt has a holding portion at one end, the force limiting wire or the force limiting steel belt being detachably held to the take-up drum by the holding portion.

7. The limited force retractor according to claim 6 wherein the retaining portion is in the form of a collar.

8. The force limiting retractor as claimed in claim 6, wherein the other end of the force limiting steel wire or the force limiting steel belt is a free end.

9. The limited force retractor according to claim 6 wherein the force limiting wire or steel belt further includes a variable engagement portion engageable with the stop member to provide a force limiting action.

10. The limited force retractor according to claim 6, wherein a holding member is provided on the spool, the holding portion being detachably held to the holding member.