Pre-tensioning and force-limiting mechanism and vehicle safety device

Abstract

Provided are a pre-tensioning and force-limiting mechanism (100) and a vehicle safety device. The pre-tensioning and force-limiting mechanism (100) comprises: a pipe body (10); a pre-tensioning assembly, wherein the pre-tensioning assembly is mounted in the pipe body (10), and comprises a moving member configured to perform reciprocating motion in the pipe body (10) and a force transmission member; and a force-limiting assembly, wherein the force-limiting assembly is mounted in the pipe body (10), and comprises a force-limiting member moving in cooperation with the pre-tensioning assembly. The pre-tensioning and force-limiting mechanism (100) is configured to be capable of switching between a pre-tensioning state and a force-limiting state; in the pre-tensioning state, the moving member is driven to drive the power transmission member to move in a first direction (D1) to achieve pre-tensioning; and in the force-limiting state, the moving member is driven by the force transmission member to move in a second direction (D2) opposite to the first direction (D1), and force-limiting is achieved by means of the force-limiting member. By providing a bidirectional constraint structure that integrates a pre-tensioning function and a force-limiting function, the force acting on a driver and passengers can be relieved, thereby reducing the harm to human bodies; and the overall structure is compact, manufacturing is easy, and the magnitude of a load or force limiting resistance can be preset on the basis of different collision resistance.

Description

Preload limiting mechanism and vehicle safety device Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular to a pre-tightening and force-limiting mechanism having both pre-tightening and force-limiting functions, and a vehicle safety device having the pre-tightening and force-limiting mechanism. Background Art

[0002] With the increasing demand for passenger protection in vehicle safety products, the market demand for pretensioners is increasing, and pretensioner products are increasingly being installed on various vehicle models. Examples of such products include lap pretensioners, pretensioner latches (or locks), and airbag retractors. Pretensioner devices typically feature a gas generator. During a collision, the gas generator, triggered according to an ignition strategy and command signal, rapidly releases gas to generate a pretensioning force and achieve locking, thereby restraining the driver and passengers and preventing excessive movement of the body, which could collide with the steering wheel or vehicle interior and cause injury.

[0003] The traditional technologies and products on the market are all one-way pre-tensioning devices, that is, after the passenger has an inevitable collision, the gas generator is detonated to achieve pre-tensioning and then locked. At the peak load, it will cause a large compressive force on the passenger and may cause greater compressive injuries. For example, the seat belt pre-tensioning latch and the pre-tensioning fixing point are locked immediately after pre-tensioning, and have no force limiting function. They cannot provide buffering to further reduce injuries during the process of restraining the driver and passengers. Therefore, in some schemes, a force limiting device is provided. The purpose of the force limiting device is to appropriately reduce the load peak during the forward movement of the driver and passengers in the event of a vehicle collision, thereby limiting the force applied to the driver and passengers. The force limiting device of the seat belt is generally integrated on the seat belt pre-retractor. The addition of the force limiting device inevitably requires an additional relatively larger installation space, and the activation or triggering of the pre-tensioning device and the force limiting device need to cooperate with each other, which also increases the control cost.

[0004] Summary of the Invention

[0005] The purpose of the present disclosure is to propose a pre-tightening and force-limiting mechanism with pre-tightening and force-limiting functions to solve the problems in the prior art. By combining the pre-tightening function and the force-limiting function, it is possible to provide pre-tightening force while absorbing the collision kinetic energy during a collision, provide appropriate restraints for the driver and passengers, and achieve safe and reliable protection.

[0006] To this end, according to one aspect of the present disclosure, a pre-tightening and force-limiting mechanism is provided, which includes: a tube body; a pre-tightening assembly, which is installed in the tube body and includes a moving part and a force transmission part suitable for reciprocating movement in the tube body; a force limiting assembly, which is installed in the tube body and includes a force limiting part that moves in coordination with the pre-tightening assembly; wherein, the pre-tightening and force-limiting mechanism is configured to be able to switch between a pre-tightening state and a force-limiting state, in which the moving part is driven and drives the force transmission part to move along a first direction to achieve pre-tightening, and in the force-limiting state, the moving part is driven by the force transmission part to move along a second direction opposite to the first direction and achieve force limiting through the force-limiting part.

[0007] According to the above technical concept, the present disclosure may further include any one or more of the following optional forms.

[0008] In some optional forms, after the moving part moves and completes the pre-tightening, it is switched from the pre-tightening state to the force-limiting state through a force transmission part.

[0009] In some optional forms, the tube body is provided with a first tube opening connected to the driving member and an opposite second tube opening, and the second tube opening is provided with a contraction portion to define a pre-tightening limit position.

[0010] In some optional forms, the driving member includes a gas generator, and in the force limiting state, the moving member overcomes the gas pressure in the tube body during the movement along the second direction to achieve force limiting.

[0011] In some optional forms, the pre-tightening assembly further comprises a limit block attached to the force transmission member and / or the moving member, and the limit block is provided with a stop portion cooperating with the contraction portion.

[0012] In some optional forms, the moving member is configured as a piston, which is sealedly engaged with the inner wall of the tube body and is provided with a through hole for the force transmission member to extend through.

[0013] In some optional forms, the force transmission member is configured as a webbing or a cable.

[0014] In certain optional forms, the piston includes a piston seat and a piston body extending from the piston seat toward the first direction, the piston seat is sealingly engaged with the inner wall of the tube body, and the piston body has a first end connected to the piston seat and a second end whose size gradually increases from the first end, and the second end is engaged with the inner wall of the tube body.

[0015] In some optional forms, the force limiting assembly includes a ball seat disposed between the piston seat and the piston body, and the force limiting member is configured as a friction ball capable of moving between the ball seat and the piston body.

[0016] In some optional forms, the ball seat is provided with circumferentially arranged limit grooves. In the pre-tightened state, the friction ball is limited in the limit grooves. In the force limiting state, the friction ball moves along the surface of the piston body in the first direction and engages with the inner wall of the tube body.

[0017] In some optional forms, the ball seat is provided with a plurality of circumferentially arranged limiting grooves, and the force limiting assembly adjusts the preset resistance by adjusting the position and / or number of the friction balls in the plurality of limiting grooves.

[0018] In some optional forms, the material of the friction ball is any one of metal, ceramic, polymer, and composite material.

[0019] According to another aspect of the present disclosure, a vehicle safety device is also provided. The vehicle safety device is suitable for any one of a safety seat, an airbag tightening device, and a safety lock, and includes a gas generator and the above-mentioned pre-tightening and force-limiting mechanism, and the tube body of the pre-tightening and force-limiting mechanism is connected to the gas generator.

[0020] The disclosed preload-limiting mechanism provides a bidirectional restraint structure that integrates preload and force-limiting functions. After preload, the mechanism does not lock, but instead functions in reverse to absorb collision kinetic energy, mitigating forces acting on the driver and passengers and minimizing harm to the body. Furthermore, the disclosed preload-limiting mechanism boasts a compact overall structure, simple manufacturing, and low cost. It can preset loads or force-limiting resistance levels based on different crashworthiness requirements, making it suitable for a variety of applications and meeting both system collision safety performance requirements and the diverse needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features and advantages of the present disclosure will be better understood through the following detailed description of the optional embodiments in conjunction with the accompanying drawings, in which the same reference numerals identify the same or similar components, wherein:

[0022] FIG1 is a cross-sectional schematic diagram of a preload-limiting mechanism applied to a vehicle safety device according to an embodiment of the present disclosure;

[0023] FIG2 is a schematic diagram of the piston in the preload-limiting mechanism of FIG1 , illustrating a method of achieving force limitation using a friction ball;

[0024] Figure 3 shows several different arrangements of the friction balls on the ball seats;

[0025] FIG4 is a cross-sectional schematic diagram of the preload-limiting mechanism in FIG1 in a preload-limiting position;

[0026] FIG5 is an enlarged schematic diagram of part A in FIG4 , showing the state of the friction ball in a pre-tightened state;

[0027] FIG6 is a schematic diagram of the pre-tightening force-limiting mechanism in FIG1 in a force-limiting state;

[0028] FIG7 is an enlarged schematic diagram of part B in FIG6 , showing the state of the friction ball in the force-limited state;

[0029] FIG8 is a schematic diagram of a preload-limiting mechanism according to the present disclosure applied to an airbag tightening device;

[0030] FIG9 is a schematic diagram of a preload force limiting mechanism according to the present disclosure applied to a vehicle waist preloader;

[0031] FIG10 is a schematic diagram of a preload-limiting mechanism according to the present disclosure applied to a vehicle preload buckle. DETAILED DESCRIPTION

[0032] The following describes the implementation and use of the embodiments in detail. However, it should be understood that the specific embodiments discussed are merely illustrative of specific ways to implement and use the present disclosure and are not intended to limit the scope of the present disclosure. When describing the structural positions of various components, such as up, down, top, and bottom, directional statements are not absolute but relative. These directional statements are appropriate when the components are arranged as shown in the figures, but if the positions of the components in the figures are changed, these directional statements will also change accordingly.

[0033] Herein, the expression “comprise” or its synonymous similar expressions “include”, “contain” and “have” are open-ended and do not exclude additional unrecited elements, steps or components.

[0034] In this document, the terms "first", "second" and the like are not used to limit the order of precedence and the number of components, unless otherwise specified.

[0035] As used herein, unless otherwise specifically defined, terms such as "mounted," "connected," and "attached" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this document based on the specific circumstances.

[0036] It should be understood that the preload-limiting mechanism disclosed herein is applicable to various appropriate vehicles. The term "vehicle" includes, but is not limited to, vehicles, ships, and aircraft. "Vehicle" includes fuel-powered vehicles, hybrid vehicles, electric vehicles, and hydrogen-powered vehicles, and can be of various types, such as small cars, buses, and rail vehicles. The application environment of the preload-limiting mechanism will be primarily described in terms of a vehicle safety device for small cars. However, this does not preclude the application of the present disclosure to other types of vehicles.

[0037] Existing vehicle pretensioning devices, such as lap pretensioners, pretensioner buckles, and airbag pretensioners, are typically equipped with a gas generator to generate pretensioning force. Once triggered, the generated gas acts on an actuator, such as a piston, to move it, and pulls a webbing or wire rope through a connector to achieve the pretensioning effect. For example, when the lap pretensioner is triggered according to the ignition strategy and command, it drives the seatbelt through the connector to eliminate the gap between the driver and the seatbelt. The pretensioner buckle is connected to the locking tongue and, when triggered according to the ignition strategy and command, tightens the seatbelt through the locking tongue. When combined with the lap pretensioner, it can achieve a better pretensioning effect. The airbag pretensioner can be installed on the seatback and connected to the airbag tensioning belt. When triggered according to the ignition strategy and command, the airbag pretensioner tightens the airbag tensioning belt, thereby adjusting the airbag to the optimal protective position.

[0038] It has been recognized that the existing pre-tensioning devices are all one-way pre-tensioning, which is locked after the pre-tensioning function is achieved, and has no unlimited force function, that is, it cannot absorb collision energy, and thus cannot reduce the pressure applied to the driver and passengers, and will cause greater compression damage to the driver and passengers at the peak of pressure. Additional force limiters require additional installation space and need to cooperate with the activation or triggering of the pre-tensioning device, which is complex to implement and has high cost. Therefore, for space and cost considerations, combining the pre-tensioning function and the force limiting function is an economical and effective way. According to the concept of the present disclosure, a pre-tensioning force limiting mechanism with bidirectional constraints is provided, which provides a force limiting function after pre-tensioning with a simple and compact structural design and economical cost-effectiveness without significantly changing the pre-tensioning device, thereby appropriately reducing the load applied to the driver and passengers during a collision.

[0039] Figures 1 to 7 illustrate an embodiment of a preload-limiting mechanism 100, comprising a tube body 10, a preload assembly, and a force-limiting assembly. Tube body 10 has a first nozzle 101 connected to a driver, which includes a gas generator 20, and an opposing second nozzle 102. The driver includes a gas generator 20. First nozzle 101 is connected to gas generator 20 via an intake manifold 11 and is provided with a sealing sleeve 12 that mates with intake manifold 11 to achieve a seal. As shown in Figure 4, second nozzle 102 has a constriction 13 to define a preload limit position. When the preload assembly reaches this limit, preload is terminated.

[0040] According to the present disclosure, the pre-tensioning assembly is installed in the tube body 10 and includes a moving part and a force transmission part suitable for reciprocating movement in the tube body 10. The force limiting assembly is installed in the tube body 10 and includes a force limiting part that moves in conjunction with the pre-tensioning assembly. In this way, the pre-tensioning and force limiting mechanism can switch between a pre-tensioning state and a force limiting state, wherein, in the pre-tensioning state, the moving part is driven by the gas generated by the gas generator 20 and drives the force transmission part to move along a first direction (for example, direction D1 in Figure 1) to achieve pre-tensioning. In the force limiting state, the moving part is driven by the force transmission part to move along a second direction opposite to the first direction (for example, direction D2 in Figure 1), overcoming the gas pressure during the movement and achieving force limiting through the force limiting part. Therefore, unlike the existing one-way pre-tensioning device, the pre-tensioning and force limiting mechanism of the present disclosure achieves two-way constraint, that is, it does not lock after pre-tensioning, but can move in the opposite direction to achieve a certain degree of pre-tensioning force release, thereby reducing the pressure or excessive load on the driver and passengers. Furthermore, according to different needs, the resistance provided by the force limiting component during reverse movement can be set to different levels, and the pre-tightening force limiting mechanism disclosed in the present invention can be applied to various occasions to achieve the force limiting function.

[0041] Advantageously, after the moving part moves and completes pre-tensioning, the force transmission member switches from the pre-tensioning state to the force-limiting state. That is, after the moving part moves with the force transmission member and achieves the pre-tensioning function, it switches directly from the pre-tensioning state to the force-limiting state without any locking or unlocking process. This is achieved by releasing the pre-tensioning force accumulated by the force transmission member during the pre-tensioning process. When the moving part and the force transmission member move to the pre-tensioning stroke, the force transmission member releases the pre-tensioning force, and the released force automatically drives the moving part in the opposite direction. During this process, the moving part continuously overcomes gas pressure and achieves force limitation through the force-limiting member. This avoids the incoordination problem caused by the separate activation or triggering control of the pre-tensioning and force-limiting functions in the prior art, making the state switching effective, reliable, and cost-effective.

[0042] It should be understood that the preload stroke may be different for different application environments, and the length of the preload stroke is related to the load. The greater the load, the smaller the stroke. In the case of a large load, the preload automatically ends after reaching equilibrium. The magnitude of the preload force also depends on the load, and the preload force threshold required for preload is, for example, about 1.5 kN to 2 kN. In the state shown in Figure 4, the preload assembly moves to the preload limit position. However, in some cases, the preload assembly does not need to move to the preload limit position, but moves along the tube body 10 in the first direction D1 to provide the set preload force threshold and then begins to move in the opposite direction along the second direction D2.

[0043] As can also be seen in FIG4 , in some embodiments, the preload assembly further includes a stopper 50 attached to the force transmission member and / or the moving member. The stopper 50 has a stopper portion 51 that engages with the constriction portion 13 of the tube body 10 to prevent the preload assembly and / or the stopper assembly from falling out of the tube body. In some embodiments, the stopper 50 may be attached with a buffer ring 52 to mitigate vibration generated when the stopper strikes the constriction portion 13.

[0044] In conjunction with Figures 1 and 2, the pre-tightening assembly that realizes the pre-tightening function can adopt any existing suitable form, such as a piston pre-tightener, a mechanical pre-tightener, etc. In the illustrated embodiment, the moving part is configured as a piston 40, which is sealed with the inner wall of the tube body 10 and is provided with a through hole 47 (Figure 3) for the force transmission part to extend through. Depending on different application environments, the force transmission part can be configured as a webbing or a cable 30 or other suitable forms. The limit block 50 can be attached to the cable 30, for example, by riveting and abut against the piston 40, so that the cable 30, the piston 40 and the limit block 50 can move in coordination. It should be understood that in a mode in which the limit block 50 is not provided, the piston 40 can be fixedly connected to the cable 30, so that the cable 30 and the piston 40 can move in coordination. When the gas generator 20 receives an ignition command and ignites, the generated high-pressure gas enters the pipe body 10 from the intake manifold 11 and provides thrust F1, driving the piston 40 and the stopper 50 along with the cable 30 in the first direction D1, thereby tightening the cable 30 and achieving a pre-tightening function. As the cable 30 is tightened, the pre-tightening force is accumulated.

[0045] In the illustrated embodiment, the piston 40 includes a piston seat 41 and a piston body 42 extending from the piston seat 41 in a first direction D1. The piston seat 41 is in sealing engagement with the inner wall of the tubular body 10. For example, the piston seat 41 is provided with a groove to accommodate a sealing ring 45, and the piston body 42 has a portion that engages with the inner wall of the tubular body 10. It should be understood that when the cable 30 releases the preload in the reverse direction, driving the piston 40 to move in the second direction D2, the engagement of the piston seat 41 and the piston body 42 with the inner wall of the tubular body 10 can both provide resistance to a certain extent, and the sealed high-pressure gas within the tubular body 10 also provides resistance. In other words, while the piston 40 moves in the second direction D2, it continuously overcomes the gas pressure within the tubular body 10 and absorbs collision energy (similar to a gas spring), thereby achieving a force-limiting function.

[0046] In certain embodiments, the piston body 42 has a first end 421 connected to the piston seat 41 and a second end 422 that gradually increases in size from the first end 421, wherein the second end 422 engages with the inner wall of the tube body 10. In this manner, the piston body 42 is formed with an inclined surface 423, which provides space for the force limiter to move during the force limiting stroke.

[0047] In some embodiments, the force limiting assembly includes a ball seat 43 disposed between the piston seat 41 and the piston body 42, and the force limiting member is configured as a friction ball 44 capable of moving between the ball seat 43 and the piston body 42. The force limiting function is achieved by the friction ball 44 moving along the inclined surface 423 of the piston body 42 in the first direction D1.

[0048] Specifically, as shown in Figures 2 and 3, the ball seat 43 is provided with circumferentially arranged limiting grooves 46. In the pre-tightened state, the friction ball 44 is limited in the limiting groove 46. In the force limiting state, the friction ball 44 moves out of the limiting groove 46 and moves along the surface (inclined surface 423) of the piston body 42 and engages with the inner wall of the tube body 10, thereby providing resistance, which will be further described in detail below.

[0049] It should be understood that the size of the friction ball 44 is associated with the distance between the inclined surface 423 of the piston body 42 and the inner wall of the tube body 10. The "association" here means that in the pre-tightened state, the friction ball 44 confined in the limiting groove contacts the inner wall of the tube body 10 but there is no force or almost no force between them, thereby not hindering the movement of the piston along the first direction D1; on the contrary, in the force-limiting state, friction is generated between the friction ball 44 and the inner wall of the tube body 10, so that the friction ball 44 gradually moves along the inclined surface 423 in the first direction D1. During this process, the inclined surface 423 and the inner wall of the tube body 10 are squeezed / deformed with the friction ball 44 to absorb energy, thereby generating friction / resistance, realizing the force-limiting function, so that excessive load will not be applied to the body of the driver and passenger, avoiding human injury.

[0050] In certain embodiments, the ball seat 43 is provided with a plurality of circumferentially arranged retaining grooves 46, such as the 10 retaining grooves 46 shown in FIG3 . The force limiting assembly can adjust the predetermined resistance level by adjusting the position and / or number of friction balls 44 within the plurality of retaining grooves 46. FIG3 illustrates the distribution of 10, 8, 6, 4, and 3 friction balls 44 within the retaining grooves 46, respectively. It should be understood that the number of retaining grooves and the number and distribution of friction balls can be appropriately designed based on different needs, as long as they provide a generally uniform and appropriate resistance level.

[0051] In addition to the position and / or number of friction balls, the resistance can also be adjusted by the material of the friction balls. Alternatively, the friction balls can be made of any of metal, ceramic, polymer, or composite materials, such as aluminum or plastic. In certain embodiments, the tube and / or piston can also be made of a material that exhibits a certain degree of deformation, such as metal or polymer.

[0052] The following describes the process of achieving pre-tightening and force limiting by the pre-tightening and force limiting mechanism of the present disclosure with reference to FIG. 4 to FIG. 7 .

[0053] Figure 4 shows the piston in the preload limit position under the thrust F1 of high-pressure gas. At this point, the stopper 51 of the stopper 50 abuts the constricted portion 13 of the tube 10, limiting its position. As mentioned above, depending on the preload stroke used in different applications, the piston may not necessarily move to the preload limit position. In the preload state, the friction ball 44 is confined in the retaining groove of the ball seat 43 and does not generate any force against the inner wall of the tube 10, as shown in Figure 5. When the preload stroke is reached, the cable 30 releases the preload force and applies a reverse tension F2. As shown in Figure 6, the cable 30 drives the stopper 50 and the piston in the second direction D2, entering the force-limiting state. At this point, referring specifically to Figure 7, the friction ball 44 moves out of the ball seat 43 and along the inclined surface 423, compressing / deforming against the inclined surface 423 and the inner wall of the tube 10, generating friction / resistance. This absorbs collision energy, eliminates peak loads, and alleviates pressure on the driver and passenger, thus achieving the force-limiting function.

[0054] The disclosed preload-limiting mechanism combines preload and force-limiting functions, not only resolving spatial layout issues encountered in existing technologies but also effectively addressing the coordination between the preload and force-limiting functions during a collision, reliably protecting drivers and passengers. Furthermore, the disclosed preload-limiting mechanism does not significantly modify existing preload devices, but advantageously incorporates a force-limiting component to provide force-limiting functionality. This results in a compact, low-cost product with stable and reliable force-limiting transmission.

[0055] Furthermore, the present disclosure provides a vehicle safety device suitable for use with any of a safety seat, an airbag retractor, or a safety buckle. The device includes a gas generator and the aforementioned preload-limiting mechanism 100, wherein the tube of the preload-limiting mechanism is connected to the gas generator. Figure 8 shows an example of its application in an airbag retractor, Figure 9 shows an example of its application in a safety seat's lap pretensioner, and Figure 10 shows an example of its application in a seatbelt's preload buckle. Depending on the collision safety requirements of different systems, the force-limiting function can be achieved by adjusting the gas pressure sealed within the tube, as well as the number, position, and material of the friction balls, to achieve a preset resistance force-limiting function and achieve appropriate restraint for the occupant. For example, when used in an airbag pretensioner, it can work together with the seatbelt / airbag to absorb the energy of the occupant's upper body movement, reducing chest pressure. When used in a lap pretensioner or preload buckle, it can reduce the pressure on the occupant's waist to a certain extent. Taking the airbag tensioning device shown in Figure 8 as an example, the preload and force-limiting mechanism 100 disclosed herein can be mounted on the seatback S and connected to the airbag tensioning strap 300. After the head airbag (HAB) is deployed according to the ignition strategy and command, the airbag tensioning strap 300 is first tightened (preload action), tightening the airbag to the appropriate preload position. When the head and chest of the occupant P come into contact with the airbag portion 200, the airbag tensioning strap 300 is pulled out (force-limiting action) to absorb the kinetic energy of the collision and prevent injury to the occupant P.

[0056] It should be understood here that the embodiments shown in the figures only show the optional architecture, shape, size and arrangement of the various optional components of the preload limiting mechanism and the vehicle safety device used according to the present disclosure. However, they are only illustrative and not restrictive. Other shapes, sizes and arrangements may also be adopted without departing from the spirit and scope of the present invention.

[0057] It should be noted that the present invention (e.g., the inventive concepts, etc.) has been described in the specification and / or illustrated in the drawings of this patent document based on exemplary embodiments; the embodiments of the present invention are presented by way of example only and are not intended to limit the scope of the present invention. The structure and / or arrangement of the elements of the inventive concepts embodied in the present invention as described in the specification and / or illustrated in the drawings is illustrative only. Although exemplary embodiments of the present invention have been described in detail in this patent document, those skilled in the art will readily appreciate that equivalents, modifications, variations, and the like of the subject matter of the exemplary embodiments and alternative embodiments are possible and are considered to be within the scope of the present invention; all such subject matter (e.g., modifications, variations, embodiments, combinations, equivalents, etc.) are intended to be included within the scope of the present invention. It should also be noted that various modifications, variations, substitutions, equivalents, changes, omissions, and the like may be made in the configuration and / or arrangement of the exemplary embodiments (e.g., in terms of concept, design, structure, apparatus, form, assembly, construction, means, function, system, process / method, steps, order of process / method steps, operation, operating conditions, performance, materials, composition, combination, etc.). ) without departing from the scope of the present invention; all such subject matter (e.g., modifications, variations, embodiments, combinations, equivalents, etc.) are intended to be included within the scope of the present invention. The scope of the present invention is not intended to be limited to the subject matter (e.g., details, structures, functions, materials, behaviors, steps, sequences, systems, results, etc.) described in the specification and / or drawings of this patent document. Considering that the claims of this patent document will be appropriately interpreted to cover the full scope of the subject matter of the present invention (e.g., including any and all such modifications, variations, embodiments, combinations, equivalents, etc.); it should be understood that the terminology used in this patent document is intended to provide a description of the subject matter of exemplary embodiments, and not as a limitation on the scope of the present invention.

[0058] It should also be noted that, depending on the exemplary embodiments, the present invention may include conventional technologies (such as those implemented and / or integrated in the exemplary embodiments, modifications, variations, combinations, equivalents), or may include any other applicable technologies (present and / or future) that have the ability to perform the functions and processes / operations described in the specification and / or illustrated in the figures. All of these technologies (such as those implemented in embodiments, modifications, variations, combinations, equivalents, etc.) are considered to be within the scope of the present invention of this patent document.

Claims

1. A preload force limiting mechanism, characterized in that: The preload force limiting mechanism comprises: tube body; A pre-tightening assembly, which is installed in the tube body and includes a moving part and a force transmission part suitable for reciprocating movement in the tube body; A force limiting assembly, which is installed in the tube body and includes a force limiting member that moves in coordination with the pre-tightening assembly; In which, the pre-tensioning and force-limiting mechanism is configured to be able to switch between a pre-tensioning state and a force-limiting state. In the pre-tensioning state, the moving part is driven and drives the force transmission part to move along a first direction to achieve pre-tensioning. In the force-limiting state, the moving part is driven by the force transmission part to move along a second direction opposite to the first direction and achieve force limiting through the force-limiting part.

2. The preload-limiting mechanism according to claim 1, characterized in that: After the moving part moves and completes the pre-tightening, the force transmission part switches from the pre-tightening state to the force limiting state.

3. The preload-limiting mechanism according to claim 1, characterized in that: The pipe body is provided with a first pipe opening connected to the driving member and a second pipe opening opposite thereto, wherein the second pipe opening is provided with a contraction portion to define a pre-tightening limit position.

4. The preload-limiting mechanism according to claim 3, characterized in that: The driving member includes a gas generator, and in the force limiting state, the moving member overcomes the gas pressure in the tube body during the movement along the second direction to achieve force limiting.

5. The preload-limiting mechanism according to claim 3, characterized in that: The pre-tightening assembly further comprises a limit block attached to the force transmission member and / or the moving member, and the limit block is provided with a stop portion cooperating with the contraction portion.

6. The preload-limiting mechanism according to any one of claims 1 to 5, characterized in that: The moving part is configured as a piston, which is sealed and engaged with the inner wall of the tube body and is provided with a through hole for the force transmission part to extend through.

7. The preload-limiting mechanism according to claim 6, characterized in that: The force transmission member is configured as a webbing or a cable.

8. The preload-limiting mechanism according to claim 6, characterized in that: The piston includes a piston seat and a piston body extending from the piston seat toward the first direction, the piston seat is sealingly engaged with the inner wall of the tube body, the piston body has a first end connected to the piston seat and a second end with a size gradually increasing from the first end, and the second end is engaged with the inner wall of the tube body.

9. The preload-limiting mechanism according to claim 8, characterized in that: The force limiting assembly includes a ball seat arranged between the piston seat and the piston body, and the force limiting member is configured as a friction ball that can move between the ball seat and the piston body.

10. The preload-limiting mechanism according to claim 9, characterized in that: The ball seat is provided with circumferentially arranged limiting grooves. In the pre-tightened state, the friction ball is limited in the limiting grooves. In the force limiting state, the friction ball moves along the surface of the piston body in the first direction and engages with the inner wall of the tube body.

11. The preload-limiting mechanism according to claim 10, characterized in that: The ball seat is provided with a plurality of limiting grooves arranged circumferentially, and the force limiting component adjusts the preset resistance size by adjusting the position and / or quantity of the friction balls in the plurality of limiting grooves.

12. The preload-limiting mechanism according to claim 9, characterized in that: The material of the friction ball is any one of metal, ceramic, polymer and composite material.

13. A vehicle safety device, characterized in that: The vehicle safety device is applicable to any one of a safety seat, an airbag tightening device, and a safety buckle, and comprises a gas generator and a pre-tensioning and force-limiting mechanism according to any one of claims 1 to 12, wherein a tube body of the pre-tensioning and force-limiting mechanism is connected to the gas generator.

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