A pre-tightening force-limiting retractor and its pre-tightening device

Abstract

The present invention provides a pre-tensioning force-limiting retractor and its pre-tensioning device, wherein the pre-tensioning device includes a pre-tensioning wheel and a pre-tensioning tube, the pre-tensioning tube has a first tube end connected to the gas generator fluid and an outlet end aligned with the pre-tensioning wheel, the pre-tensioning tube is provided with a sealing ball and a driving ball in sequence between the first tube end and the outlet end, the sealing ball and the driving ball can move toward the pre-tensioning wheel along a first direction in the pre-tensioning tube in response to the actuation of the gas generator; along the first direction, the pre-tensioning tube includes a connected sealing section and a degassing section, a recessed pressure relief groove is provided on the inner wall of the degassing section, the sealing ball is sealed with the inner wall of the sealing section, and the sealing ball is degassing with the inner wall of the degassing section through the pressure relief groove. The present invention can realize automatic pressure relief of the pre-tensioning tube during the pre-tensioning process, avoiding the force-limiting overshoot phenomenon caused by excessive gas pressure in the pre-tensioning tube.

Description

Technical Field

[0001] The invention relates to the technical field of automobile safety belt retractors, and in particular to a pre-tightening force-limiting retractor and a pre-tightening device thereof. Background Art

[0002] The car seat belt is a safety device that restrains the occupants in the event of a collision, to prevent the occupants from having a secondary collision with the steering wheel and dashboard, or from being thrown out of the car and causing death or injury. The retractor is the core component of the car seat belt, which is used to lock the seat belt webbing in an emergency.

[0003] At present, many mid-to-high-end cars use pre-tensioning and force-limiting retractors with pre-tensioning and force-limiting functions. When a car collides, the pre-tensioning device first forces the webbing reel to rotate in the tightening direction to pull back the webbing to eliminate the excess tension of the webbing, thereby binding the person to the seat, that is, realizing the pre-tensioning function of the retractor. Afterwards, the force-limiting device allows the webbing reel to rotate in the loosening direction, thereby allowing the webbing to be loosened to a certain length to avoid the occupant's chest from being greatly impacted by the webbing.

[0004] Generally speaking, the pretensioning device of the pretensioning force-limited retractor includes a pretensioning tube and a pretensioning wheel. A gas generator, a sealing ball and a driving ball are arranged in the pretensioning tube. The sealing ball and the driving ball can be driven by the pressure generated by the gas generator, and fly out from the outlet of the pretensioning tube and hit the pretensioning wheel to drive the pretensioning wheel to rotate, thereby driving the webbing reel to rotate in the tightening direction, thereby pulling back the webbing to eliminate the excess tension of the webbing.

[0005] The problem with the existing pre-tensioning force-limiting retractors is that during the pre-tensioning process, when the pre-tensioning condition is switched to the force-limiting condition, that is, after the pre-tensioning device tightens the webbing and when the force-limiting device starts to pull the webbing out, due to the high pressure in the pre-tensioning tube, a high webbing force (resistance) will be generated and added to the force-limiting device, and the webbing pulling force will temporarily increase to a higher force-limiting level limited by the force-limiting device. This effect is usually called force-limiting overshoot.

[0006] That is to say, due to the excessively high gas pressure in the pretensioning tube, when the webbing is switched from the pretensioning condition to the force limiting condition, the webbing force will experience an abnormally high force limiting overshoot phenomenon, which will significantly reduce the restraint performance of the webbing.

[0007] Therefore, how to reduce the gas pressure in the pre-tightening pipe to avoid overshoot of the force limit without affecting the pre-tightening function has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0008] In view of this, the purpose of the present invention is to provide a pressure relief structure in the pretensioning tube to reduce the gas pressure in the pretensioning tube during the pretensioning process, thereby avoiding overshoot of the force limit. In addition, the pressure relief structure in the pretensioning tube should be simplified to make the pretensioning device more cost-effective.

[0009] In order to achieve one of the above-mentioned purposes, the present invention provides a pretensioning device in a first aspect, which is arranged on a pretensioning force-limiting retractor, and comprises a pretensioning wheel and a pretensioning tube, wherein the pretensioning tube has a first tube end in fluid communication with a gas generator and an outlet end aligned with the pretensioning wheel, and the pretensioning tube is provided with a sealing ball and a driving ball in sequence between the first tube end and the outlet end, and the sealing ball and the driving ball can move toward the pretensioning wheel in a first direction in the pretensioning tube in response to the actuation of the gas generator;

[0010] Along the first direction, the preload tube includes a connected sealing section and an air release section, a recessed pressure relief groove is provided on the inner wall of the air release section, the sealing ball is sealed with the inner wall of the sealing section, and the sealing ball is air-released with the inner wall of the air release section through the pressure relief groove.

[0011] Preferably, the inner diameter of the air leakage section is larger than the inner diameter of the sealing section;

[0012] The sealing ball is fitted with an inner wall of the sealing section in an interference fit, and the sealing ball is fitted with an inner wall of the pressure relief portion end in a small clearance fit.

[0013] Preferably, the inner walls of the sealing section and the air release section adopt a step-type transition or a sloped gradual transition.

[0014] Preferably, the pressure relief groove is a strip-shaped groove extending from its starting point along the direction of the pretensioning pipe to the outlet end of the pretensioning pipe.

[0015] Preferably, the number of the pressure relief grooves is four, and the four pressure relief grooves are evenly arranged along the circumferential direction of the air relief section.

[0016] Preferably, the pressure relief groove is square or arc-shaped.

[0017] Preferably, the outer wall of the preload tube is configured as a smooth surface.

[0018] Preferably, a convex rib corresponding to the pressure relief groove is provided on the outer wall of the air release section of the preload pipe at a position corresponding to the pressure relief groove.

[0019] Has beneficial effects:

[0020] It can be seen from the above technical solution that when a vehicle collides, the sealing ball first moves in the first direction in the sealing section under the impetus of the high-temperature and high-pressure gas generated by the gas generator, thereby driving the driving ball to move in the first direction and fly out of the outlet end of the pre-tensioning tube to hit the pre-tensioning wheel, and then driving the pre-tensioning wheel to rotate in the direction of webbing tightening to rewind the webbing to eliminate the excess tension of the webbing. After that, the sealing ball enters the degassing section from the sealing section, and the inner wall of the degassing section has a pressure relief groove. In this way, when the sealing ball enters the degassing section, the high-temperature and high-pressure gas in the pre-tensioning tube can be released through the pressure relief groove, thereby achieving pressure relief of the pre-tensioning tube in the later stage of the pre-tensioning process, avoiding the force limiting overshoot phenomenon caused by excessive gas pressure in the pre-tensioning tube.

[0021] In addition, the present invention realizes the pressure relief of the pre-tensioning pipe by arranging a pressure relief groove in the air relief section of the pre-tensioning pipe, which has simple structural features, is easy to manufacture, and reduces production costs.

[0022] The second aspect of the present invention further provides a pre-tensioning force-limiting retractor, comprising a pre-tensioning device, wherein the pre-tensioning device is a pre-tensioning device as described in any one of the above items. Since the pre-tensioning force-limiting retractor provided in the second aspect of the present invention adopts the pre-tensioning device provided in the first aspect of the present invention, it has corresponding beneficial effects, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 It is a structural schematic diagram of the pre-tightening device of the present invention;

[0025] Figure 2 It is a three-dimensional schematic diagram of the pre-tightening tube of the pre-tightening device of the present invention;

[0026] Figure 3 for Figure 2 A cross-sectional view of the preload tube shown;

[0027] Figure 4 It is a schematic diagram of the structure of the sealing cooperation between the sealing ball and the sealing section of the present invention;

[0028] Figure 5 It is a schematic structural diagram of the air-deflating cooperation between the sealing ball and the air-deflating section of the present invention;

[0029] Figure 6 It is a webbing tension curve diagram of an existing pre-tensioning force-limiting retractor;

[0030] Figure 7It is a webbing tension curve diagram of the pre-tightening force-limiting retractor of the present invention;

[0031] Reference Numbers

[0032] 1- preload wheel; 1a- ball groove;

[0033] 2-preload tube; 2a-first tube end; 2b-exit end; 21-sealing section; 22-deflation section;

[0034] 3- Sealing ball;

[0035] 4-Drive the ball;

[0036] 5- air release trough;

[0037] 6- ribs;

[0038] 7- Transition zone. DETAILED DESCRIPTION

[0039] The core of the present invention is to provide a pre-tightening force-limiting retractor and a pre-tightening device thereof, which automatically reduces the gas pressure in the pre-tightening pipe during the pre-tightening process to avoid force-limiting overshoot while ensuring the pre-tightening function of the retractor.

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figure 1-5 , Figure 1 It is a structural schematic diagram of the pre-tightening device of the present invention; Figure 2 It is a three-dimensional schematic diagram of the pre-tightening tube of the pre-tightening device of the present invention; Figure 3 for Figure 2 A cross-sectional view of the preload tube shown; Figure 4 It is a schematic diagram of the structure of the sealing cooperation between the sealing ball and the sealing section of the present invention; Figure 5 It is a schematic structural diagram of the air leakage cooperation between the sealing ball and the air leakage section of the present invention.

[0042] The first aspect of the embodiment of the present invention discloses a pre-tightening device, which is arranged on a pre-tightening force-limiting retractor, and can not only realize the normal tightening of the safety belt when a vehicle collision accident occurs, but also reduce the overshoot phenomenon of the limit.

[0043] Specifically, Figure 1As shown, the pretensioning device provided by the present invention comprises a pretensioning wheel 1 and a pretensioning tube 2. The pretensioning tube 2 has a first tube end 2a in fluid communication with the gas generator and an outlet end 2b aligned with the pretensioning wheel 1. The pretensioning tube 2 is provided with a sealing ball 3 and a plurality of driving balls 4 in sequence between the first tube end 2a and the outlet end 2b.

[0044] When a collision occurs, the gas generator at the first tube end 2a of the pre-tensioning tube 2 is activated and exploded to generate high-temperature and high-pressure gas. Under the impetus of the high-temperature and high-pressure gas, the sealing ball 3 and the driving ball 4 move in the pre-tensioning tube 2 along the first direction toward the pre-tensioning wheel 1, and then a plurality of driving balls 4 fly out from the outlet end 2b of the pre-tensioning tube 2 in sequence and engage with the ball groove 1a on the pre-tensioning wheel 1, thereby impacting the pre-tensioning wheel 1, and then driving the pre-tensioning wheel 1 to rotate in the direction of webbing tightening, that is, the pre-tensioning wheel 1 moves along the first direction. Figure 1 The pre-tensioning wheel 1 then drives the webbing reel to rotate in the tightening direction, thereby rewinding the webbing and eliminating the excess tension of the webbing, that is, realizing the pre-tensioning function of the retractor. It should be noted that the structural features and working principles of the pre-tensioning wheel 1 and the webbing reel are the same as those of the prior art, and will not be described in detail here.

[0045] When the webbing is switched from the pre-tightening condition to the force-limiting condition, that is, after the webbing is tightened and at the beginning of pulling out the webbing, the high gas pressure in the pre-tightening tube 2 will form resistance to pulling out the webbing, and at this time, the webbing force will increase abnormally, that is, the force-limiting overshoot will occur. The force-limiting overshoot will significantly reduce the restraint performance of the webbing.

[0046] Based on this, the present invention optimizes the structure of the pretensioning tube 2 and can automatically reduce the gas pressure of the pretensioning tube 2 during the pretensioning process to reduce the force limiting overshoot while ensuring the normal pretensioning function of the pretensioning device.

[0047] like Figure 2-5 As shown, specifically, in the present invention, the preload tube 2 includes a sealing section 21 and a degassing section 22 connected in sequence along the first direction, wherein a concave pressure relief groove 5 is provided on the inner wall of the degassing section 22. The sealing ball 3 is sealed with the inner wall of the sealing section 21, and the sealing ball 3 is degassing with the inner wall of the degassing section 22 through the pressure relief groove 5.

[0048] It can be seen from the above technical solution that when a collision occurs in a vehicle, the sealing ball 3 first moves in the sealing section 21 along the first direction under the driving effect of the high-temperature and high-pressure gas generated by the gas generator, thereby driving the multiple driving balls 4 to move along the first direction. Then the driving ball 4 close to the outlet end 2b of the pre-tensioning tube 2 will first fly out of the pre-tensioning tube 2, thereby driving the pre-tensioning wheel 1 to rotate in the direction of webbing tightening, so as to rewind the webbing and eliminate the excess tension of the webbing. After that, the sealing ball 3 enters the degassing section 22 from the sealing section 21. Since the inner wall of the degassing section 22 has a pressure relief groove 5, the high-temperature and high-pressure gas in the pre-tensioning tube 2 can be released through the pressure relief groove 5, thereby achieving pressure relief of the pre-tensioning tube 2 in the later stage of the pre-tensioning process.

[0049] As can be seen from the above description, the pretensioning device provided by the present invention realizes automatic pressure relief of the pretensioning tube 2 in the latter part of the retractor pretensioning process. When the retractor switches from the pretensioning condition to the force limiting condition, that is, after the pretensioning device tightens the webbing and when the force limiting device pulls out the webbing, that is, when the force limiting function of the retractor is just started, the air pressure in the pretensioning tube 2 is reduced, thereby reducing the resistance to pulling out the webbing, so that a high webbing force will not be generated to be added to the force limiting device, thereby avoiding overshoot of the force limiting.

[0050] It is understandable that in the pretensioning device provided by the present invention, in the front process of the retractor pretensioning process, since the sealing ball 3 and the sealing section 21 are sealed and matched, the air pressure in the pretensioning tube 2 will not decrease, and will not affect the response speed of the retractor to the pretensioning function; in the back process of the retractor pretensioning process, the air pressure in the pretensioning tube 2 is automatically reduced, which effectively avoids the force limiting overshoot. It should be noted that those skilled in the art can design the size of the pressure relief groove 5 according to the actual situation, so as not to affect the process of the driving ball 4 moving forward in the first direction while releasing the pressure. In other words, the pretensioning device provided by the present invention neither affects the normal pretensioning function of the webbing, but can significantly reduce the force limiting overshoot phenomenon.

[0051] It is also necessary to emphasize that the present invention realizes pressure relief of the preload tube 2 by providing a pressure relief groove 5 on the inner wall of the pressure relief section 22 of the preload tube 2. The structure is simple, easy to manufacture, and has good practicality and popularization.

[0052] like Figure 3 As shown, optionally, the inner diameter of the air release section 22 is larger than the inner diameter of the sealing section 21, and the sealing ball 3 is interference-fitted with the inner wall of the sealing section 21, thereby achieving a sealing fit between the sealing ball 3 and the sealing section 21. The sealing ball 3 is fitted with a small gap with the inner wall of the pressure relief section end 22, thereby facilitating the movement of the sealing ball 3 in the air release section 22.

[0053] The transition zone 7 of the inner wall of the sealing section 21 and the air release section 22 can adopt a step-type transition or a slope-type gradual transition. In this way, during the pre-tightening process, it is convenient for the sealing ball 3 to smoothly enter the air release section 22 from the sealing section 21.

[0054] In a preferred embodiment, the pressure relief groove 5 is a strip groove extending from its starting point along the direction of the preload tube 2 to the outlet end 2b of the preload tube 2. In this way, the air relief groove 5 is set as a strip groove extending along the direction of the preload tube 2. When the sealing ball 3 enters the air relief section 22 from the sealing section 21 and moves forward in the first direction in the air relief section 22, the gas pressure in the preload tube 2 is gradually released, so as to achieve the purpose of stable pressure relief without affecting the normal movement of the driving ball 4.

[0055] It should be noted that the number of the pressure relief groove 5 is at least one, and those skilled in the art can set the number of the pressure relief groove 5 according to the actual situation. For example, in a specific embodiment, the number of the pressure relief grooves 5 can be specifically set to four, and the four pressure relief grooves 5 can be evenly arranged along the circumferential direction of the air relief section 22.

[0056] It should be noted that the groove shape of the pressure relief groove 5 in the present invention can be square, arc-shaped, or other shapes, and the groove shape of the pressure relief groove 5 is not specifically limited here. In a preferred embodiment, the groove shape of the pressure relief groove 5 can be square or arc-shaped. The processing method of the pressure relief groove 5 is broaching or extrusion molding, which is convenient for processing and reduces production costs.

[0057] like Figure 2 As shown, in a further embodiment, a convex rib 6 corresponding to the pressure relief groove 5 is provided on the outer wall of the air release section 22 of the preload tube 2 at a position corresponding to the pressure relief groove 5, thereby improving the strength of the air release section 22. Of course, under the premise of meeting the strength requirement, the outer wall of the preload tube 2 can also be set to a smooth surface, that is, without a convex rib, thereby improving the external aesthetics of the preload tube 2.

[0058] The second aspect of the embodiment of the present invention further provides a pre-tensioning force-limiting retractor, comprising a pre-tensioning device, wherein the pre-tensioning device is a pre-tensioning device as described in any one of the above items. Since the pre-tensioning force-limiting retractor provided in the second aspect of the present invention adopts the pre-tensioning device provided in the first aspect of the present invention, it has corresponding beneficial effects, which will not be described in detail here.

[0059] In order to verify the effect of the above-mentioned pre-tightening device of the present invention on reducing force-limiting overshoot, the applicant conducted webbing tension tests on the existing pre-tightening force-limiting retractor and the pre-tightening force-limiting retractor provided by the present invention and drew corresponding webbing tension curves.

[0060] like Figure 6The figure shows the webbing tension curve of the existing pre-tensioning force-limiting reel. It can be seen that since the pre-tensioning tube of the existing pre-tensioning force-limiting reel does not have the above-mentioned pressure relief structure, when switching from the pre-tensioning condition to the force-limiting condition, due to the excessively high gas pressure in the pre-tensioning tube, obvious force-limiting overshoot will occur.

[0061] like Figure 7 The figure shows the webbing tension curve of the pre-tensioning force-limiting retractor provided by the present invention. It can be seen that since the above-mentioned pressure relief structure is designed in the pre-tensioning tube, when switching from the pre-tensioning condition to the force-limiting condition, the gas pressure in the pre-tensioning tube is released, thereby effectively avoiding the force-limiting overshoot phenomenon.

[0062] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0063] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0064] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A pretensioning device, arranged on a pretensioning force-limiting retractor, comprising a pretensioning wheel and a pretensioning tube, wherein the pretensioning tube has a first tube end in fluid communication with a gas generator and an outlet end aligned with the pretensioning wheel, wherein the pretensioning tube is provided with a sealing ball and a driving ball in sequence between the first tube end and the outlet end, wherein the sealing ball and the driving ball can move in the pretensioning tube along a first direction toward the pretensioning wheel in response to actuation of the gas generator; It is characterized in that Along the first direction, the preload tube includes a connected sealing section and a gas relief section, the inner wall of the gas relief section is provided with a concave pressure relief groove, the sealing ball is sealed with the inner wall of the sealing section, and the sealing ball is gas-released with the inner wall of the gas relief section through the pressure relief groove; the inner diameter of the gas relief section is larger than the inner diameter of the sealing section; The sealing ball is interference fit with the inner wall of the sealing section, and the sealing ball is small gap fit with the inner wall of the pressure relief portion end; the pressure relief groove is a strip groove extending from its starting point along the direction of the preload tube to the outlet end of the preload tube.

2. The preload device according to claim 1, characterized in that: The inner walls of the sealing section and the air release section adopt a step-type transition or a slope-type gradual transition.

3. The preload device according to claim 1, characterized in that: The number of the pressure relief grooves is specifically four, and the four pressure relief grooves are evenly arranged along the circumferential direction of the air relief section.

4. The preload device according to claim 1, characterized in that: The groove shape of the pressure relief groove is square or arc-shaped.

5. The preload device according to claim 1, characterized in that: The outer wall of the preload tube is configured as a smooth surface.

6. The preload device according to claim 1, characterized in that: A convex rib corresponding to the pressure relief groove is arranged on the outer wall of the air release section of the preload pipe at a position corresponding to the pressure relief groove.

7. A pre-tightening force-limiting retractor, comprising a pre-tightening device, characterized in that: The pre-tensioning device is the pre-tensioning device according to any one of claims 1 to 6.

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