EP-4737225-A1 - PRE-TENSIONING AND FORCE-LIMITING MECHANISM AND VEHICLE SAFETY DEVICE

EP4737225A1EP 4737225 A1EP4737225 A1EP 4737225A1EP-4737225-A1

Abstract

The present disclosure provides a pre-tightening and force-limiting mechanism and a vehicle safety device. The pre-tightening and force-limiting mechanism (100) comprises: a tube body (10); a pre-tightening assembly mounted in the tube body (10) and comprising a moving component and a force-transmitting component which are adapted to reciprocate in the tube body (10); and a force-limiting assembly mounted in the tube body (10) and comprising a force-limiting component which moves in cooperation with the pre-tightening assembly. The pre-tightening and force-limiting mechanism is configured to be switchable between a pre-tightening state in which the moving component is driven and drives the force-transmitting component to move in a first direction (D1) to realize pre-tightening, and a force-limiting state in which the moving component is driven by the force-transmitting component to move in a second direction (D2) opposite to the first direction (D1) and to realize force-limiting by the force-limiting component. The pre-tightening and force-limiting mechanism of the present disclosure provides a bidirectional constraint structure integrating the pre-tightening function and the force-limiting function, which alleviates the force acting on the driver and the passenger and reduces the injury to the human body. The pre-tightening and force-limiting mechanism has a compact overall structure and is simple to manufacture, which can preset the resistance of load or force limiting according to different crashability.

Inventors

LIU, Chongqing
ZHAO, WEI
ZHENG, Shenghui
YANG, LUN

Assignees

Yanfeng International Automotive Technology Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20240614

Claims (13)

A pre-tightening and force-limiting mechanism (100), comprising: a tube body (10); a pre-tightening assembly mounted in the tube body (10) and comprising a moving component and a force-transmitting component which are adapted to reciprocate in the tube body (10); and a force-limiting assembly mounted in the tube body (10) and comprising a force-limiting component which moves in cooperation with the pre-tightening assembly; wherein the pre-tightening and force-limiting mechanism is configured to be switchable between a pre-tightening state in which the moving component is driven and drives the force-transmitting component to move in a first direction (D1) to realize pre-tightening, and a force-limiting state in which the moving component is driven by the force-transmitting component to move in a second direction (D2) opposite to the first direction (D1) and to realize force-limiting by the force-limiting component.
The pre-tightening and force-limiting mechanism (100) according to claim 1, wherein the moving component is switched immediately from the pre-tightening state to the force-limiting state by the force-transmitting component after the moving component is moved and completes the pre-tightening.
The pre-tightening and force-limiting mechanism (100) according to claim 1, wherein the tube body (10) is provided with a first tube opening (101) connected to a driving component and an opposite second tube opening (102), and the second tube opening (102) is provided with a contracting portion (13) to define a pre-tightening limit position.
The pre-tightening and force-limiting mechanism (100) according to claim 3, wherein the driving component comprises a gas generator (20), and in the force-limiting state, the moving component overcomes gas pressure in the tube body (10) during movement in the second direction (D2) to realize the force-limiting.
The pre-tightening and force-limiting mechanism (100) according to claim 3, wherein the pre-tightening assembly further comprises a limiting block (50) attached to the force-transmitting component and/or the moving component, and the limiting block (50) is provided with a stop portion (51) matched with the contracting portion (13).
The pre-tightening and force-limiting mechanism (100) according to any one of claims 1 to 5, wherein the moving component is configured as a piston (40), and the piston (40) is in sealing engagement with an inner wall of the tube body (10) and is provided with a through hole (47) through which the force-transmitting component extends.
The pre-tightening and force-limiting mechanism (100) according to claim 6, wherein the force-transmitting component is configured as a webbing or a tension cable (30).
The pre-tightening and force-limiting mechanism (100) according to claim 6, wherein the piston (40) comprises a piston seat (41) and a piston body (42) extending from the piston seat (41) toward the first direction (D1), the piston seat (41) is in sealing engagement with the inner wall of the tube body (10), the piston body (42) has a first end (421) connected to the piston seat (41) and a second end (422) increasing in size from the first end (421), and the second end (422) is engaged with the inner wall of the tube body (10).
The pre-tightening and force-limiting mechanism (100) according to claim 8, wherein the force-limiting assembly comprises a ball seat (43) disposed between the piston seat (41) and the piston body (42), and the force-limiting component is configured as a friction ball (44) movable between the ball seat (43) and the piston body (42).
The pre-tightening and force-limiting mechanism (100) according to claim 9, wherein the ball seat (43) is provided with a limiting groove (46) arranged circumferentially, in the pre-tightening state, the friction ball (44) is limited in the limiting groove (46), and in the force-limiting state, the friction ball (44) moves along the surface of the piston body (42) in the first direction (D1) and engages with the inner wall of the tube body (10).
The pre-tightening and force-limiting mechanism (100) according to claim 10, wherein the ball seat (43) is provided with a plurality of limiting grooves (46) arranged circumferentially, and the force-limiting assembly adjusts a preset resistance by adjusting the positions and/or the number of the friction balls (44) in the plurality of limiting grooves (46).
The pre-tightening and force-limiting mechanism (100) according to claim 9, wherein the material of the friction ball (44) is any one of metal, ceramic, polymer, and composite material.
A vehicle safety device, wherein the vehicle safety device is applicable to any one of safety seat, airbag tightening device and safety buckle, and comprises a gas generator (20) and a pre-tightening and force-limiting mechanism (100) according to any one of claims 1 to 12, and a tube body (10) of the pre-tightening and force-limiting mechanism (100) is connected to the gas generator (20).

Description

FIELD The present disclosure relates to the technical field of vehicles, and in particular to a pre-tightening and force-limiting mechanism having both pre-tightening function and force-limiting function, and a vehicle safety device having the pre-tightening and force-limiting mechanism. BACKGROUND With the increasing demand of vehicle safety products for passenger protection, the demand for pre-tightening devices in the market is increasing, and the configuration rate of pre-tightening products of various vehicle models is getting higher and higher. Such products include, for example, waist pre-tensioner, pre-tightening plug lock (or buckle), airbag tensioner, etc. The pre-tightening device is usually equipped with a gas generator. In the process of collision, after the gas generator is triggered according to ignition strategy and instruction signal, the gas generator quickly releases gas to generate a pre-tightening force and realize locking, thus restraining driver and passenger and preventing the human body from moving excessively and colliding with steering wheel or vehicle interior trim to cause injury. Conventional technologies and products in the market are one-way pre-tightening devices, that is, the pre-tightening device is locked after the gas generator is ignited to realize pre-tightening when the passenger have an inevitable collision, which will cause greater compression force to the passenger at the peak of load and may cause greater compression injury. For example, a safety belt pre-tightening plug lock and a pre-tightening fixed point are locked immediately after pre-tightening, and there is no force limiting function, and no buffer can be performed during the process of restraining the driver and the passenger to further reduce injuries. Thus, in some solutions, a force limiting device is provided. The purpose of the force limiting device is to appropriately reduce the peak of load during forward movement of the driver and the passenger in the event of a vehicle collision, thereby limiting the force exerted on the driver and the passenger. The force limiting device of the safety belt is generally integrated on a safety belt pre-contracting retractor, the addition of the force limiting device inevitably requires additional relatively increased mounting space, and the activation or triggering of the pre-tightening device and the force limiting device needs to cooperate with each other, which also increases the control cost. SUMMARY The purpose of the present disclosure is to provide a pre-tightening and force-limiting mechanism with pre-tightening function and force-limiting function to solve the problems in the prior art. By combining the pre-tightening function with the force-limiting function, the pre-tightening force can be provided and the collision kinetic energy can be absorbed at the same time during collision, which provides appropriate constraints for the driver and passenger and realizes safe and reliable protection. To this end, according to an aspect of the present disclosure, a pre-tightening and force-limiting mechanism is provided. The pre-tightening and force-limiting mechanism comprises: a tube body; a pre-tightening assembly mounted in the tube body and comprising a moving component and a force-transmitting component which are adapted to reciprocate in the tube body; and a force-limiting assembly mounted in the tube body and comprising a force-limiting component which moves in cooperation with the pre-tightening assembly, wherein the pre-tightening and force-limiting mechanism is configured to be switchable between a pre-tightening state in which the moving component is driven and drives the force-transmitting component to move in a first direction to realize pre-tightening, and a force-limiting state in which the moving component is driven by the force-transmitting component to move in a second direction opposite to the first direction and to realize force-limiting by the force-limiting component. According to the above technical concept, the present disclosure may further include any one or more of the following alternative forms. In some alternative forms, the moving component is switched immediately from the pre-tightening state to the force-limiting state by the force-transmitting component after the moving component is moved and completes the pre-tightening. In some alternative forms, the tube body is provided with a first tube opening connected to a driving component and an opposite second tube opening, and the second tube opening is provided with a contracting portion to define a pre-tightening limit position. In some alternative forms, the driving component comprises a gas generator, and in the force-limiting state, the moving component overcomes gas pressure in the tube body during movement in the second direction to realize the force-limiting. In some alternative forms, the pre-tightening assembly further comprises a limiting block attached to the force-transmit