Safety belt retractor

Abstract

The utility model discloses a safety belt retractor, and relates to the technical field of safety. The safety belt retractor comprises a pre-tightening assembly and a winding assembly connected with the pre-tightening assembly. The pre-tightening assembly comprises a stop wheel and a ball gear, the stop wheel is sleeved with the ball gear in an anti-torque mode, the stop wheel is provided with a first curved surface, the ball gear is provided with a second curved surface, the first curved surface and the second curved surface jointly define a ball bin, and the ball bin is used for containing a pre-tightening ball. The centers of the ball bins are jointly located on a preset plane, one part of the second curved surface and the first curved surface are located on one side of the preset plane, and the other part of the second curved surface is located on the other side of the preset plane. The pre-tightening assembly in the safety belt retractor provided by the utility model uses fewer parts, is convenient to assemble and has better reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of safety, in particular to a safety belt retractor. BACKGROUND

[0002] In a motor vehicle, a safety belt device is an important component of a passenger restraint system, which can provide protection for a passenger in a traffic accident, so as to avoid or minimize the injury of the passenger. With the development and progress of motor vehicle technology, the performance of the safety belt device is continuously improved. Some safety belt devices can activate a locking mechanism under predetermined conditions, so that a winding assembly with a safety belt wound thereon is locked in a unwinding direction.

[0003] The existing safety belt device further includes related components for realizing a pretensioning function, which can pretension the safety belt in an emergency of the vehicle, so as to better restrain the passenger of the vehicle. For example, the safety belt retractor includes a stop wheel, a driving wheel, a winding assembly and a gas generator. When the gas generator is detonated, a plurality of steel balls are successively emitted from each other, and cooperate with a plurality of ball pockets on the driving wheel, so that the driving wheel drives the stop wheel and the winding assembly to perform a winding movement, thereby realizing pretensioning.

[0004] However, the driving wheel in the related art is composed of two parts, both of which are sleeved on the stop wheel and jointly form the ball pocket for accommodating the steel balls. The inner walls of the ball pockets formed by the two parts are axially spaced on both sides of the center point of the ball pocket. Such a safety belt retractor has a large number of parts and poor reliability. CONTENT OF THE UTILITY MODEL

[0005] The purpose of the present application includes providing a safety belt retractor with a simple and reliable structure.

[0006] Embodiments of the present application can be implemented as follows:

[0007] The present application provides a safety belt retractor, which includes a pretensioning assembly and a winding assembly connected with the pretensioning assembly, the winding assembly being used for winding a safety belt, the pretensioning assembly including a stop wheel and a ball gear, the ball gear being torsionally sleeved on the stop wheel, the stop wheel being provided with a plurality of first curved surfaces arranged in a circumferential direction of the stop wheel, the ball gear being provided with a plurality of second curved surfaces arranged in a circumferential direction of the ball gear, the number of the first curved surfaces being equal to that of the second curved surfaces and corresponding one by one, each first curved surface and its corresponding second curved surface jointly forming a ball pocket, the ball pocket being used for accommodating a pretensioning ball, the centers of the plurality of ball pockets being located on a preset plane, a part of the second curved surfaces being located on one side of the preset plane, and the other part of the second curved surfaces being located on the other side of the preset plane.

[0008] In an optional embodiment, the first curved surface is a concave spherical surface, the second curved surface comprises a first sub curved surface and a second sub curved surface connected in sequence, the first sub curved surface is a concave spherical surface, the second sub curved surface is a concave cylindrical surface, the second sub curved surface is located on the same side of the preset plane as the first curved surface, one end of any generatrix of the second sub curved surface is connected to the first sub curved surface, and the other end extends toward the first curved surface.

[0009] In an optional embodiment, the intersection line of the first sub curved surface and the second sub curved surface is located on the preset plane.

[0010] In an optional embodiment, any generatrix on the second sub curved surface is tangent to the first sub curved surface.

[0011] In an optional embodiment, the generatrix of the second sub curved surface is parallel to the axis of the spherical gear.

[0012] In an optional embodiment, the stop wheel has opposite first and second ends in the axial direction of the stop wheel, the first curved surface and the second curved surface are arranged in the axial direction of the stop wheel, and the second curved surface is closer to the first end of the stop wheel than the first curved surface, and the first end of the stop wheel is connected to the winding assembly.

[0013] In an optional embodiment, the stop wheel has a first outer peripheral surface, the spherical gear has a first inner peripheral surface, the spherical gear is sleeved outside the first outer peripheral surface, and the first inner peripheral surface is opposite to the first outer peripheral surface in the radial direction, one end of the first outer peripheral surface close to the first end of the stop wheel is provided with a limiting portion, and the limiting portion is used for abutting against the spherical gear to limit the axial movement of the spherical gear.

[0014] In an optional embodiment, one of the first inner peripheral surface and the first outer peripheral surface is provided with a first boss, and the other of the first inner peripheral surface and the first outer peripheral surface is provided with a first groove, and the first boss is matched with the first groove.

[0015] In an optional embodiment, the second end of the stop wheel is provided with a locking mechanism, and the locking mechanism is used for preventing the pre-tightening assembly and the winding assembly from rotating in the unwinding direction under a set condition.

[0016] In an optional embodiment, the winding assembly comprises a force limiting piece and a winding drum, the outer peripheral side of the winding drum is used for winding the safety belt, and the winding drum is connected to the first end of the stop wheel through the force limiting piece.

[0017] In an optional embodiment, the force limiting piece is rod-shaped, the first end of the stop wheel is provided with a cylindrical connecting portion, one end of the force limiting piece is inserted and matched with the cylindrical connecting portion, one of the inner wall of the cylindrical connecting portion and the force limiting piece is provided with a second boss, and the other of the inner wall of the cylindrical connecting portion and the force limiting piece is provided with a second groove, and the second boss is matched with the second groove.

[0018] In an optional embodiment, the force limiting member is in the shape of a rod, the first end of the stop wheel is provided with a cylindrical connecting portion, one end of the force limiting member is inserted into the cylindrical connecting portion and is connected to the cylindrical connecting portion in a torsion-proof manner; a winding drum is sleeved outside the force limiting member, and the end of the force limiting member away from the stop wheel is connected to the winding drum in a torsion-proof manner.

[0019] In an optional embodiment, the seat belt retractor further comprises a frame, and the stop wheel and the winding assembly are rotatably connected to the frame.

[0020] In an optional embodiment, the seat belt retractor further comprises a gas generator, a pipe and a set of pre-tightening balls, the gas generator is used to generate gas to input the pre-tightening balls along the pipe into the ball pocket of the pre-tightening assembly, so that the pre-tightening assembly and the winding assembly have a tendency to rotate in the winding direction.

[0021] The seat belt retractor provided by the embodiments of the present application has the following beneficial effects:

[0022] The seat belt retractor provided by the embodiments of the present application comprises a pre-tightening assembly and a winding assembly connected to the pre-tightening assembly, the winding assembly is used to wind a seat belt, the pre-tightening assembly comprises a stop wheel and a ball gear, the ball gear is sleeved on the stop wheel in a torsion-proof manner, the stop wheel is provided with a plurality of first curved surfaces arranged around the circumference of the stop wheel, the ball gear is provided with a plurality of second curved surfaces arranged around the circumference of the ball gear, the number of the first curved surfaces is equal to that of the second curved surfaces and each first curved surface corresponds to a second curved surface, each first curved surface and the corresponding second curved surface jointly enclose a ball pocket, the centers of the plurality of ball pockets are located on a preset plane, a part of the second curved surfaces is located on one side of the preset plane relative to the first curved surfaces, and the other part of the second curved surfaces is located on the other side of the preset plane relative to the first curved surfaces. In the present application, since the first curved surfaces that form part of the inner wall surface of the ball pocket are formed by the stop wheel, only one ball gear with second curved surfaces needs to be sleeved on the stop wheel to form the ball pocket. The pre-tightening assembly with such a structure has fewer parts and is convenient to assemble; the stop wheel itself participates in forming the ball pocket, thus simplifying the transmission relationship and improving the reliability. Moreover, compared with the prior art, the second curved surfaces on the ball gear have a longer extension length in the axial direction of the ball gear in the present application, so that a part of the second curved surfaces is located on the same side of the preset plane relative to the first curved surfaces; that is, in the axial direction of the ball gear, the second curved surfaces are distributed on both sides of the center point of the ball pocket. Such a design can improve the radial component of the force exerted by the pre-tightening ball on the ball gear after the pre-tightening ball enters the ball pocket, and can relatively reduce the axial component, thus relieving the tendency of the ball gear to move away from the first curved surfaces, increasing the locking force between the ball gear and the stop wheel, preventing the separation of the two during the pre-tightening process to cause the dissipation of pre-tightening energy, and thus improving the reliability of the pre-tightening assembly. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those of ordinary skill in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 A schematic view of a pre-tightening assembly in a first perspective view according to an embodiment of the present application;

[0025] Figure 2 A schematic view of a pre-tightening assembly in a second perspective view according to an embodiment of the present application;

[0026] Figure 3 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application;

[0027] Figure 4 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application; Figure 3 A sectional view in the A direction according to an embodiment of the present application;

[0028] Figure 5 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application;

[0029] Figure 6 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application;

[0030] Figure 7 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application; Figure 4 An enlarged view of a portion VII according to an embodiment of the present application;

[0031] Figure 8 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application;

[0032] Figure 9 A schematic view of a pre-tightening assembly in a third perspective view according to an embodiment of the present application; Figure 8 A sectional view in the B direction according to an embodiment of the present application.

[0033] Figure: 100 - pre-tightening assembly; 110 - stop wheel; 110a - first end; 110b - second end; 111 - cylindrical connecting portion; 112 - first outer peripheral surface; 113 - first groove; 114 - second outer peripheral surface; 115 - second inner peripheral surface; 116 - second boss; 117 - accommodating groove; 118 - limiting portion; 119 - shaft head; 120 - ball gear; 121 - first inner peripheral surface; 122 - first boss; 130 - ball housing; 131 - first curved surface; 132 - second curved surface; 1321 - first sub curved surface; 1322 - second sub curved surface; 200 - pre-tightening ball. DETAILED DESCRIPTION

[0034] To make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0036] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0037] In the description of the present application, it should be noted that if the terms “upper”, “lower”, “inner”, “outer” and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the utility model product is used, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0038] In addition, if the terms “first”, “second” and the like appear, they are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0039] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0040] In the related art, as disclosed in the application file with publication number CN113119905A, the ball bin is composed of two parts sleeved on the stop wheel, and the two parts are torsionally connected with the stop wheel to transmit torque. This safety belt retractor uses more parts, resulting in complex assembly, and the reliability of transmission will also decrease. Moreover, the two parts forming the ball bin have two spherical surfaces (since they enclose the ball bin), which are respectively located on both sides of the center point of the ball bin in the axial direction of the safety belt retractor, which makes the two parts have a tendency to move away from each other when the pre-tightening ball enters the ball bin and presses the two spherical surfaces, which also leads to a decrease in the reliability of the safety belt retractor.

[0041] To this end, the application provides a seat belt retractor, which comprises a ball cage formed by a stop wheel and a ball gear, and has a simple structure and high reliability.

[0042] Figure 1 A schematic view of a pretensioning assembly 100 in a first perspective view according to an embodiment of the application; Figure 2 A schematic view of a pretensioning assembly 100 in a second perspective view according to an embodiment of the application; Figure 3 A schematic view of a pretensioning assembly 100 in a third perspective view according to an embodiment of the application. Figures 1 to 3 As shown in the drawings, the seat belt retractor according to an embodiment of the application comprises a pretensioning assembly 100 and a winding assembly (not shown in the drawings) connected to the pretensioning assembly 100, the winding assembly being configured to wind a seat belt. The winding assembly and the pretensioning assembly 100 are connected in a torsion-resistant manner, so that the winding assembly and the pretensioning assembly 100 can transmit a certain range of torque. In the application, the "torsion-resistant connection" can mean that the two components connected cannot or substantially cannot rotate relative to each other. Due to the unintentional gap (for example, due to manufacturing errors), or due to the intentional gap (for example, due to the intentional design of a number of degrees of free play), or due to the elasticity of each component of the entire connection system, the two components connected can also slightly rotate relative to each other or can rotate relative to each other with a predetermined free play. For example, when the two components are welded or bonded together, or are assembled with an interference fit or are integrally manufactured, they can rotate together, so they can be considered to be connected in a torsion-resistant manner.

[0043] In the embodiment of the application, the winding assembly and the pretensioning assembly 100 can be coaxially arranged, i.e., they can rotate along a common axis. When the pretensioning assembly 100 is not locked, the winding assembly and the pretensioning assembly 100 can rotate synchronously. When the winding assembly rotates, the seat belt can be wound around the outer periphery of the winding assembly (i.e., reeled up), or the seat belt can be released from the winding assembly (i.e., unreeled), so the reeling-up movement and the unreeled movement of the winding assembly are two rotation movements in opposite directions, which are configured to realize the reeling-up and unreeled of the seat belt. The reeling-up movement and the unreeled movement of the pretensioning assembly 100 should also be understood in the above manner.

[0044] In the embodiment of the application, the seat belt retractor can comprise a frame, and the pretensioning assembly 100 (specifically, the stop wheel 110 described below) and the winding assembly are rotatably connected to the frame. The frame can be fixedly connected to other external components to realize the fixation of the seat belt retractor.

[0045] Figure 4 A schematic view of a pretensioning assembly 100 in a first perspective view according to an embodiment of the application; Figure 3 A sectional view in the A direction; Figure 5This is a schematic diagram of the ball gear 120 in one embodiment of this application; Figure 6 This is a schematic diagram of the stop wheel 110 in one embodiment of this application. Figures 4 to 6 As shown, the preload assembly 100 includes a stop wheel 110 and a ball gear 120. The ball gear 120 is torsionally fitted onto the stop wheel 110, meaning that the ball gear 120 is fitted onto the stop wheel 110 and cannot or substantially cannot rotate relative to the stop wheel 110. It should be understood that due to unintentional clearance (e.g., due to manufacturing errors), or due to intentional clearance (e.g., due to intentionally designed clearance of a certain degree), or due to the elasticity of the various components of the entire connection system, the ball gear 120 may rotate slightly relative to the stop wheel 110 or may rotate relative to the stop wheel 110 with a predetermined clearance. The stop wheel 110 has multiple first curved surfaces 131 arranged circumferentially around it, and the ball gear 120 has multiple second curved surfaces 132 arranged circumferentially around it. The number of first curved surfaces 131 and second curved surfaces 132 are equal and correspond one-to-one. Each first curved surface 131 and its corresponding second curved surface 132 together form a ball chamber 130, which is used to accommodate the preloaded ball 200. The center O of the multiple ball chambers 130 is located on a preset plane. Figure 4 (M indicates the plane). In this embodiment, the preset plane M is perpendicular to the rotation axis of the stop wheel 110 and the ball gear 120. In this embodiment, both the first curved surface 131 and the second curved surface 132 are continuous curved surfaces. A portion of the second curved surface 132 and the first curved surface 131 are located on one side of the preset plane, and another portion of the second curved surface 132 is located on the other side of the preset plane. Figure 4 As can be seen, a portion of the ball gear 120 extends beyond the preset plane M to the other side of the preset plane M (i.e., Figure 4 (Left side of the preset plane M).

[0046] Figure 7 for Figure 4 Enlarged view of section VII in the middle; Figure 8 This is a schematic diagram of the pre-tensioned ball 200 located in the ball chamber 130 in one embodiment of this application; Figure 9 for Figure 8 A sectional view along the B-direction. (Combined with...) Figures 4 to 9In an alternative embodiment of the present application, the first curved surface 131 is a concave spherical surface; the second curved surface 132 comprises a first sub-curved surface 1321 and a second sub-curved surface 1322 connected to each other, the first sub-curved surface 1321 is a concave spherical surface, the second sub-curved surface 1322 is a concave cylindrical surface, the second sub-curved surface 1322 is located on the same side of the preset plane as the first curved surface 131, one end of any generatrix of the second sub-curved surface 1322 is connected to the first sub-curved surface 1321, and the other end extends to the first curved surface 131. By setting the first curved surface 131 and the first sub-curved surface 1321 as concave spherical surfaces, the fitting with the pre-tightening ball 200 can be increased, and the space utilization of the ball pocket 130 can be improved. Alternatively, the centers of curvature of the first curved surface 131 and the first sub-curved surface 1321 coincide, and the center of curvature of the first curved surface 131 and the first sub-curved surface 1321 is the center O of the ball pocket 130.

[0047] It should be understood that the concave cylindrical surface can be obtained by sweeping a generatrix along the extension path of the directrix (perpendicular to the generatrix). In the present embodiment, the generatrix of the second sub-curved surface 1322 is parallel to the axis of the ball gear 120.

[0048] Alternatively, any generatrix on the second sub-curved surface 1322 is tangent to the first sub-curved surface 1321. By setting the generatrix of the second sub-curved surface 1322 to be tangent to the first sub-curved surface 1321, there is no corner angle between the first sub-curved surface 1321 and the second sub-curved surface 1322, and the transition between the two is smoother. In alternative embodiments, the first sub-curved surface 1321 and the second sub-curved surface 1322 can have a corner angle at the connection, which can be an outward convex angle or an inward concave angle.

[0049] In the present embodiment, the intersection line of the first sub-curved surface 1321 and the second sub-curved surface 1322 is located on the preset plane. It can be understood that when the first sub-curved surface 1321 of the spherical surface intersects with the second sub-curved surface 1322 of the cylindrical surface, the intersection line should be an arc, and in the present embodiment, the plane where the arc lies is the preset plane M. Further, since the generatrix of the second sub-curved surface 1322 is tangent to the first sub-curved surface 1321 and parallel to the axis of the ball gear 120, the point of the first sub-curved surface 1321 closest to the axis of the ball gear 120 is located on the intersection line of the first sub-curved surface 1321 and the second sub-curved surface 1322.

[0050] In alternative embodiments, part or all of the intersection line of the first sub-curved surface 1321 and the second sub-curved surface 1322 can also be located on the same side of the preset plane M as the first curved surface 131 and the second sub-curved surface 1322; that is, part of the first sub-curved surface 1321 can extend to the other side of the preset plane M Figure 7In this case, the lowest point of the second curved surface 132 closest to the axis of the ball gear 120 is located on the first sub curved surface 1321, and when the pre-tightening ball 200 axially presses the pre-tightening assembly 100, the part of the first sub curved surface 1321 crossing the preset plane M will bear an axial force component, which can alleviate the tendency of the ball gear 120 to move away from the first curved surface 131, thereby improving the reliability of the ball gear 120.

[0051] Alternatively, the part of the ball gear 120 axially crossing the preset plane M and used to form the second sub curved surface 1322 can be continuous in the circumferential direction to form an annular structure; in other embodiments, the plurality of solid parts used to form the second sub curved surface 1322 can also be discontinuous in the circumferential direction, in which case the ball gear 120 appears to have a plurality of protrusions arranged in the circumferential direction and protruding in the axial direction.

[0052] Again referring to Figures 4 to 6 In this embodiment, the stop wheel 110 has opposite first and second ends 110a and 110b in the axial direction thereof, and the first and second curved surfaces 131 and 132 are arranged in the axial direction of the stop wheel 110, with the second curved surface 132 being closer to the first end 110a of the stop wheel 110 than the first curved surface 131, and the first end 110a of the stop wheel 110 being connected to the winding assembly.

[0053] Further, the stop wheel 110 has a first outer circumferential surface 112, and the ball gear 120 has a first inner circumferential surface 121, with the ball gear 120 being sleeved outside the first outer circumferential surface 112 and the first inner circumferential surface 121 being opposite to the first outer circumferential surface 112 in the radial direction. A limiting portion 118 is protruded on one end of the first outer circumferential surface 112 close to the first end 110a of the stop wheel 110, and is used to abut against the ball gear 120 to limit the axial movement of the ball gear 120. In this embodiment, the ball gear 120 is sleeved on the first outer circumferential surface 112 from the first end 110a of the stop wheel 110. The first outer circumferential surface 112 and the first inner circumferential surface 121 can be in interference fit. Specifically, the limiting portion 118 abuts against the end surface of the ball gear 120 facing the winding assembly, so that the ball gear 120 is blocked by the limiting portion 118 and cannot move towards the first end 110a of the stop wheel 110. Alternatively, the limiting portion 118 can be obtained by plastically deforming the stop wheel 110 by applying an external force thereto, so that the entire stop wheel 110 is of an integral structure. For example, when assembling the pre-tightening assembly 100, the ball gear 120 can be sleeved from the first end 110a of the stop wheel 110, and then a force is applied to cause plastic deformation of the first end 110a of the stop wheel 110, so as to lock the ball gear 120 outside the first outer circumferential surface 112. Alternatively, the stop wheel 110 and the ball gear 120 can be made of a metal material (including an alloy), and the ball gear 120 can be implemented by a cold forming process.

[0054] In the embodiment, the stop wheel 110 and the ball gear 120 can be connected in a torque-proof manner through a spline fit. Alternatively, one of the first inner circumferential surface 121 and the first outer circumferential surface 112 is provided with a first protrusion 122, and the other of the first inner circumferential surface 121 and the first outer circumferential surface 112 is provided with a first recess 113, and the first protrusion 122 is fitted in the first recess 113. In the embodiment, the first inner circumferential surface 121 is provided with the first protrusion 122, and the first outer circumferential surface 112 is provided with the first recess 113 fitted in the first protrusion 122. Alternatively, the first protrusion 122 and the first recess 113 are in an interference fit. It can be understood that in other embodiments, the stop wheel 110 and the ball gear 120 can be connected in other ways, such as an interference fit between the first inner circumferential surface 121 and the first outer circumferential surface 112, and a torque-proof connection is achieved only by relying on the damping between the two; or one end of the ball gear 120 in the axial direction is provided with a protrusion, and the recess provided on the stop wheel 110 is fitted in the axial direction; or the ball gear 120 can be connected to the stop wheel 110 in a torque-proof manner by adhesion or welding.

[0055] Alternatively, the winding assembly comprises a force limiting member and a winding drum. The outer circumferential side of the winding drum is used to wind the safety belt, and the winding drum is connected to the first end 110a of the stop wheel 110 through the force limiting member. It should be understood that the force limiting member is used to transmit torque, so that the winding drum can rotate synchronously with the pretensioning assembly 100 during the pretensioning stage or normal winding and unwinding of the safety belt; in addition, the force limiting member can maintain the torque without further increasing when the torque reaches a certain threshold. For example, when the force limiting member transmits a low torque, the deformation of the force limiting member is elastic deformation; when the torque transmitted by the force limiting member rises to the threshold, the force limiting member itself plastically deforms, so that the torque no longer rises, and the corresponding pulling force of the safety belt remains constant, thereby reducing the compression of the safety belt on the chest of the occupant and providing better protection effect.

[0056] Alternatively, the force limiting member is rod-shaped, and the first end 110a of the stop wheel 110 is provided with a cylindrical connecting portion 111, and one end of the force limiting member is fitted in the cylindrical connecting portion 111. Alternatively, the force limiting member and the cylindrical connecting portion 111 can be connected in a torque-proof manner through a spline fit. Alternatively, one of the inner wall of the cylindrical connecting portion 111 and the force limiting member is provided with a second protrusion 116, and the other of the inner wall of the cylindrical connecting portion 111 and the force limiting member is provided with a second recess, and the second protrusion 116 is fitted in the second recess. In the embodiment, the cylindrical connecting portion 111 and the force limiting member are connected through a spline structure, and the second protrusion 116 is further provided on the protruding portion on the second inner circumferential surface 115, and the second protrusion 116 extends in the axial direction of the stop wheel 110 and is used to be fitted in the second recess on the force limiting member.

[0057] By connecting the force limiting member to the stop wheel 110, torque can be transmitted through the winding drum, the force limiting member, and the stop wheel 110; in alternative embodiments, the force limiting member can also be connected to the ball gear 120 in a torsion-resistant manner, and torque can be transmitted through the winding drum, the force limiting member, the ball gear 120, and the stop wheel 110.

[0058] Further, the winding drum is sleeved outside the force limiting member, and the end of the force limiting member away from the stop wheel 110 is connected to the winding drum in a torsion-resistant manner. Alternatively, the sleeve connecting portion also has a second outer circumferential surface 114 with a diameter smaller than that of the first outer circumferential surface 112, and the end of the winding drum close to the pretensioning assembly 100 has a second inner circumferential surface 115 that can be sleeved outside the second outer circumferential surface 114, and the winding drum can rotate relative to the sleeve connecting portion without considering the torsion-resistant connection of the force limiting member.

[0059] In the present embodiment, the second end 110b of the stop wheel 110 is provided with a locking mechanism (not shown in the figure), which is used to prevent the pretensioning assembly 100 and the winding assembly from rotating in the unwinding direction under a set condition. The set condition can be that the rotation speed of the pretensioning assembly 100 and the winding assembly in the unwinding movement is higher than a set threshold, which means that when the safety belt is pulled out too fast (which may occur when the vehicle collides in actual use), the locking mechanism can lock the pretensioning assembly 100 so that the pretensioning assembly 100 cannot continue to rotate; and since there is a torsion-resistant connection relationship between the winding assembly and the pretensioning assembly 100, within a certain torque range, the winding assembly will also stop unwinding movement together with the pretensioning assembly 100, so as to tension the safety belt that has been pulled out.

[0060] Alternatively, the second section of the stop wheel 110 can be provided with a locking pawl (not shown in the figure), and a locking member (not shown in the figure) can be fixedly installed on the frame. The locking pawl can move within a certain stroke relative to the stop wheel 110, so as to cooperate with or disengage from the locking member. When the locking pawl cooperates with the locking member, the stop wheel 110 cannot do unwinding movement due to the blocking action of the locking member. The locking pawl is connected to a pretensioning spring, and the locking pawl can be kept disengaged from the locking member under the action of the elastic force of the pretensioning spring, and can cooperate with the locking member to lock the stop wheel 110 by overcoming the spring force of the pretensioning spring. Alternatively, the locking pawl can be a ratchet pawl, and the locking member can be provided with a ratchet tooth, and the locking pawl can cooperate with the locking member by overcoming the elastic force of the pretensioning spring through centrifugal force when the stop wheel 110 does unwinding movement and the rotation speed reaches a certain degree, so as to achieve the locking of the stop wheel 110. In the present embodiment, the stop wheel 110 is provided with a receiving groove 117 for accommodating the locking pawl.

[0061] In addition, the seat belt retractor can further comprise a vehicle sensing device (not shown in the figure) connected with the stop wheel 110. The vehicle sensing device can detect the safety-related state of the vehicle, such as the vehicle acceleration and the vehicle inclination angle, and when the vehicle acceleration or the vehicle inclination angle exceeds the corresponding threshold, the locking of the stop wheel 110 can be caused, thereby preventing the seat belt from being continuously pulled out of the winding assembly. The vehicle sensing device can be linked with the locking mechanism, so as to cause the locking mechanism to lock the stop wheel 110 when the vehicle is detected to meet the set condition.

[0062] In the embodiment, the second end 110b of the stop wheel 110 is further provided with a shaft head 119, which can be rotatably connected with the frame, thereby supporting the pre-tightening assembly 100.

[0063] The seat belt retractor provided by the embodiment can further comprise a coil spring (not shown in the figure), which is used to provide an elastic force to the winding assembly and / or the pre-tightening assembly 100, so as to make the winding assembly have a tendency of winding movement. In this way, the seat belt retractor can keep the seat belt tensioned in normal use, and can be retracted as much as possible when the seat belt is not used.

[0064] Further, the seat belt retractor further comprises a gas generator (not shown in the figure), a pipeline (not shown in the figure) and a group of pre-tightening balls 200. The gas generator is used to generate gas to input the pre-tightening balls 200 along the pipeline into the ball warehouse 130 of the pre-tightening assembly 100, so as to make the pre-tightening assembly 100 and the winding assembly have a tendency of rotating in the winding direction. In a specific scenario, when it is detected that the vehicle is abnormal (such as detecting that the acceleration and / or inclination is too large through the vehicle sensing device), the gas generator can be triggered. When the gas generator is triggered, gas is generated to push the pre-tightening balls 200 along the pipeline into the ball warehouse 130 of the pre-tightening assembly 100. The inertia of the pre-tightening balls 200 makes the pre-tightening assembly 100 generate rotation in the winding direction, and the winding assembly is driven by the pre-tightening assembly 100 to make winding movement at the same time, so that the seat belt is tightened, and the pre-tightening function is realized. The pre-tightening assembly 100 can further have a ball accumulator (not shown in the figure), through which the pre-tightening balls 200 entering the ball warehouse 130 and the flame and debris generated by the gas generator can be prevented from being discharged into the internal space of the vehicle.

[0065] In summary, the embodiment of the present application provides a safety belt retractor. The safety belt retractor comprises a pretensioning assembly 100 and a winding assembly connected with the pretensioning assembly 100, the winding assembly is used for winding the safety belt, the pretensioning assembly 100 comprises a stop wheel 110 and a ball gear 120, the ball gear 120 is torsionally connected with the stop wheel 110, the stop wheel 110 is provided with a plurality of first curved surfaces 131 arranged around the circumference of the stop wheel 110, the ball gear 120 is provided with a plurality of second curved surfaces 132 arranged around the circumference of the ball gear 120, the number of the first curved surfaces 131 is equal to that of the second curved surfaces 132, and the first curved surfaces 131 and the second curved surfaces 132 are one-to-one corresponding, each first curved surface 131 and the corresponding second curved surface 132 jointly enclose a ball pocket 130, the ball pocket 130 is used for accommodating a pretensioning ball 200, the centers of the plurality of ball pockets 130 are located on a preset plane, the first curved surfaces 131 and the second curved surfaces 132 are continuous curved surfaces, a part of the second curved surfaces 132 is located on one side of the preset plane with the first curved surfaces 131, and the other part of the second curved surfaces 132 is located on the other side of the preset plane. In the present application, since the first curved surfaces 131 forming part of the inner wall surface of the ball pocket 130 are formed by the stop wheel 110, only one ball gear 120 with the second curved surfaces 132 needs to be connected with the stop wheel 110, and the ball pocket 130 is formed. The pretensioning assembly 100 with the above structure has less parts and is convenient to assemble; the stop wheel 110 itself participates in forming the ball pocket 130, so that the transmission relationship is simplified, and the reliability is better. Moreover, compared with the prior art, the second curved surfaces 132 on the ball gear 120 have a longer extension length in the axial direction of the ball gear 120, so that a part of the second curved surfaces 132 is located on the same side of the preset plane with the first curved surfaces 131; that is, in the axial direction of the ball gear 120, the second curved surfaces 132 are distributed on both sides of the center point of the ball pocket 130. This design can improve the radial component of the force applied by the pretensioning ball 200 to the ball gear 120 after the pretensioning ball 200 enters the ball pocket 130, and relatively reduce the axial component, so that the trend of the ball gear 120 moving away from the first curved surfaces 131 can be alleviated, the locking force of the ball gear 120 and the stop wheel 110 is increased, the separation of the two in the pretensioning process is prevented, the pretensioning energy is prevented from being dissipated, and the reliability of the pretensioning assembly 100 is improved.

[0066] The above merely describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical range disclosed by the present application can be easily thought of by those skilled in the art, and should be covered in the protection scope of the present application.

Claims

1. A seat belt retractor characterized by, The pre-tightening assembly (100) comprises a stop wheel (110) and a ball gear (120), the ball gear (120) is torsionally sleeved on the stop wheel (110), the stop wheel (110) is provided with a plurality of first curved surfaces (131) arranged in the circumferential direction of the stop wheel (110), the ball gear (120) is provided with a plurality of second curved surfaces (132) arranged in the circumferential direction of the ball gear (120), the first curved surfaces (131) and the second curved surfaces (132) are equal in number and one-to-one corresponding, each first curved surface (131) and its corresponding second curved surface (132) jointly form a ball pocket (130) for accommodating a pre-tightening ball (200), the centers of a plurality of ball pockets (130) are located on a preset plane, a part of the second curved surfaces (132) is located on one side of the preset plane with the first curved surfaces (131), and the other part of the second curved surfaces (132) is located on the other side of the preset plane.

2. The seat belt retractor of claim 1 wherein, The first curved surface (131) is a concave spherical surface, the second curved surface (132) comprises a first sub-surface (1321) and a second sub-surface (1322) connected with each other, the first sub-surface (1321) is a concave spherical surface, the second sub-surface (1322) is a concave cylindrical surface, the second sub-surface (1322) is located on the same side of the preset plane with the first curved surface (131), and one end of any generatrix of the second sub-surface (1322) is connected to the first sub-surface (1321) and the other end extends to the first curved surface (131).

3. The seat belt retractor of claim 2 wherein, The intersection line of the first sub-surface (1321) and the second sub-surface (1322) is located on the preset plane.

4. The seat belt retractor of claim 2 wherein, Any generatrix on the second sub-surface (1322) is tangent to the first sub-surface (1321).

5. The seat belt retractor of claim 2 wherein, The generatrix of the second sub-surface (1322) is parallel to the axis of the ball gear (120).

6. The seat belt retractor according to any one of claims 1-5, wherein, The stop wheel (110) has opposite first and second ends (110a, 110b) in the axial direction thereof, the first curved surfaces (131) and the second curved surfaces (132) are arranged in the axial direction of the stop wheel (110), and the second curved surfaces (132) are closer to the first end (110a) of the stop wheel (110) relative to the first curved surfaces (131), and the first end (110a) of the stop wheel (110) is connected with the winding assembly.

7. The seat belt retractor of claim 6 wherein, The stop wheel (110) has a first outer circumferential surface (112), the cogwheel (120) has a first inner circumferential surface (121), the cogwheel (120) is sleeved outside the first outer circumferential surface (112), and the first inner circumferential surface (121) is opposite to the first outer circumferential surface (112) in the radial direction. A limiting portion (118) is protruded on one end of the first outer circumferential surface (112) close to a first end (110a) of the stop wheel (110), and the limiting portion (118) is used for abutting against the cogwheel (120) to limit the axial movement of the cogwheel (120).

8. The seat belt retractor of claim 7 wherein, One of the first inner circumferential surface (121) and the first outer circumferential surface (112) is provided with a first boss (122), and the other of the first inner circumferential surface (121) and the first outer circumferential surface (112) is provided with a first groove (113), and the first boss (122) is matched with the first groove (113).

9. The seat belt retractor of claim 6 wherein, A second end (110b) of the stop wheel (110) is provided with a locking mechanism, which is used for preventing the pretensioning assembly (100) and the winding assembly from rotating in the unwinding direction under a set condition.

10. The seat belt retractor according to any one of claims 1-5, wherein, The winding assembly comprises a force limiting piece and a winding drum, and the winding drum is used for winding the safety belt on the outer circumferential side of the winding drum. The winding drum is connected to the first end (110a) of the stop wheel (110) through the force limiting piece.

11. The seat belt retractor of claim 10 wherein, The force limiting piece is rod-shaped, the first end (110a) of the stop wheel (110) is provided with a cylindrical connecting portion (111), one end of the force limiting piece is inserted into the cylindrical connecting portion (111) and is connected to the cylindrical connecting portion (111) in a torsion-resistant manner. The winding drum is sleeved outside the force limiting piece, and one end of the force limiting piece away from the stop wheel (110) is connected to the winding drum in a torsion-resistant manner.

12. The seat belt retractor of claim 10 wherein, The safety belt retractor further comprises a frame, and the stop wheel (110) and the winding assembly are rotatably connected to the frame.

13. The seat belt retractor according to any one of claims 1-5, wherein, The safety belt retractor further comprises a gas generator, a pipeline and a group of pretensioning balls (200). The gas generator is used for generating gas to input the pretensioning balls (200) along the pipeline into the ball chamber (130) of the pretensioning assembly (100), so that the pretensioning assembly (100) and the winding assembly have a tendency to rotate in the winding direction.

14. The seat belt retractor according to any one of claims 1-5, wherein, ​

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