CN114043959B

CN114043959B - Knee air bag assembly, air bag pre-folding assembly and air bag device

Info

Publication number: CN114043959B
Application number: CN202111382728.1A
Authority: CN
Inventors: 徐振翔; 王东; 郑重; 潘绿英
Original assignee: Ningbo Junsheng Automobile Safety System Co ltd
Current assignee: Ningbo Junsheng Automobile Safety System Co ltd
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2023-02-28
Anticipated expiration: 2041-11-22
Also published as: CN114043959A

Abstract

The airbag assembly is inflated and unfolded, the front cavity is at least partially inflated before the rear cavity, and the rear cavity extends to a position between the leg of a passenger and the instrument panel; the front cavity and the rear cavity are both provided with a communication panel pointing to the instrument panel, and an included angle formed between the front cavity communication panel and the rear cavity communication panel in a non-mounted inflation state is smaller than an included angle formed between a horizontal plane where a mounting point of the front cavity is located and the instrument panel corresponding to the leg of a passenger in a mounted state. Through the processing scheme of this application, realize the big corner of gasbag more easily and expand, adapt to the instrument board molding of different whole cars.

Description

Knee air bag assembly, air bag pre-folding assembly and air bag device

Technical Field

The present application relates to the field of airbags, and more particularly, to a knee airbag assembly, an airbag pre-fold assembly, and an airbag device.

Background

The knee airbag of the existing design, especially the knee airbag installed at the bottom of the automobile instrument panel, is generally formed by sewing and connecting an integral cloth piece with different numbers of drawstrings, and at the position of an inflection point of the unfolding, a part of the cloth piece close to one side of the instrument panel is cut off and is sewn together, so that the bent structure matched with the shape of the instrument panel is formed. This structure is likely to be oriented toward the occupant during the deployment of the airbag, and may not be deployed well along the instrument panel, which may eventually result in failure of the airbag to be deployed normally.

Disclosure of Invention

In view of this, the present application provides a knee air bag assembly, an air bag pre-folding assembly and an air bag device, which solve the problems in the prior art, and are more easily to realize the large-corner unfolding of the air bag, so as to adapt to different instrument panel shapes of the whole vehicle.

The knee air bag assembly provided by the application adopts the following technical scheme:

a knee airbag assembly comprising a split front and rear chamber, the front chamber being at least partially secured to the underside of the vehicle dashboard and communicating with the rear chamber, the front chamber being at least partially inflated prior to the rear chamber during inflation deployment of the airbag assembly, the rear chamber extending between the occupant's leg and the dashboard;

the front cavity and the rear cavity are both provided with a communication panel pointing to the instrument panel, and an included angle formed between the front cavity communication panel and the rear cavity communication panel in a non-mounted inflation state is smaller than an included angle formed between a horizontal plane where a mounting point of the front cavity is located and the instrument panel corresponding to the leg of a passenger in a mounted state.

Optionally, in an uninstalled inflated state, an included angle formed between the front cavity communication panel and the rear cavity communication panel is less than 90 °.

Optionally, the front chamber mounting point is located one side of keeping away from the passenger on the front chamber intercommunication panel, back chamber intercommunication panel lower part is equipped with a plurality of air vents of arranging along vehicle width direction, the intercommunication panel of front chamber is close to passenger one side and is equipped with the air vent of corresponding arranging, along the air vent will front chamber intercommunication panel with back chamber intercommunication panel is fixed.

Optionally, a first abutting portion is provided between a side of the vent hole facing the occupant in the front chamber and a distal end of the front chamber facing the occupant, and a second abutting portion abutting against the first abutting portion is provided below the vent hole in the rear chamber.

Optionally, the length of the first abutment is the same as the length of the second abutment.

Optionally, the rear cavity is formed by folding the integrated cloth piece relatively and then sewing edges, the vent holes are located at one end far away from the folding lines, a plurality of extending lines of the vent holes are parallel to the folding lines, and the folding lines divide the rear cavity into a protection side panel and a communication panel.

Optionally, the rear cavity further comprises a plurality of pull belts distributed at intervals, the pull belts extend along the folding line direction, two side edges of the pull belts are respectively connected with the protection side panel and the communication panel of the rear cavity, and the pull belts are provided with air holes distributed at intervals.

Optionally, the antechamber is followed by rectangular shape cloth piece the central line fifty percent discount on the long limit of rectangular shape cloth piece is made up the border and is formed, the central line will the antechamber divide into front panel and intercommunication panel, the extending direction of the air vent of antechamber intercommunication panel with the central line is perpendicular, the erection site department in antechamber is equipped with the bolt hole, the bolt hole is used for gas generator's bolt to pass, the air vent and the bolt hole in antechamber are located respectively the both sides of central line extending direction, rectangular shape cloth piece be provided with the mounting hole that penetrates for gas generator on the central line.

The knee air bag pre-folding assembly provided by the application adopts the following technical scheme:

the utility model provides a knee air pocket is folding assembly in advance, includes as above knee air pocket assembly, gas generator and wrapping cloth, wrapping cloth one end with the bolt hole is made up, and the other end is the free end, the free end is equipped with and is used for the cover to establish the trepanning on gas generator's bolt, gas generator gives vent to anger the end and inserts the front chamber, the gas generator bolt certainly the front chamber mounting point stretches out, wrapping cloth's free end is around coiling and/or folding behind front chamber and the back chamber, the trepanning cover is established on gas generator's bolt.

The knee airbag device provided by the application adopts the following technical scheme:

a knee airbag device comprising a case mounted at the instrument panel bottom, a cover plate provided with an opening toward the vehicle bottom and a bottom wall toward the vehicle top, the cover plate being turnably fastened to the opening, a bolt of a gas generator mounted on the side of the bottom wall away from an occupant, the front and rear chambers being wound and/or folded being disposed on the side of the case facing the occupant, and the pre-folding assembly as described above in 9.

Optionally, the middle part of the wrapping cloth is sewn with the front cavity between the vent hole and the bolt hole through a pre-sewing line, the front cavity is folded back from the pre-sewing line towards one side far away from the rear cavity to form a folded-back part, a concave structure facing towards a passenger is arranged on the folded-back part, and the rear cavity is wrapped by the wrapping cloth after being wound and/or folded in the concave structure.

Optionally, a distance between the mounting point of the front cavity and the pre-seam line is less than or equal to the width of the bottom wall of the housing.

Optionally, the pre-seam line is sewn through the front panel and the communicating panel of the front cavity.

Optionally, the upper portion of the rear cavity is folded and the lower portion of the rear cavity is folded in a Z shape and then is received in the concave structure.

To sum up, the application comprises the following beneficial technical effects:

1. when the air bag assembly is not installed, namely when the air bag assembly is inflated under the condition of no restriction, the included angle formed between the front cavity and the rear cavity is smaller and even reaches a parallel state, when the air bag assembly is installed at the bottom of an instrument panel of a finished automobile, the front cavity is inflated and unfolded preferentially and extends out after being inflated, the unfolding position and the angle are controlled at the initial unfolding stage of the air bag assembly, meanwhile, the unfolding of the rear cavity is supported, the rear cavity is restrained by the instrument panel in the unfolding process, the included angle between the rear cavity and the front cavity is increased, and the rear cavity and the front cavity are unfolded along the trend of the instrument panel;

2. the first abutting part of the front cavity and the second abutting part of the rear cavity abut against each other, so that the rear cavity can be folded, the rear cavity can be unfolded at a large corner conveniently, and the instrument panel can be attached quickly;

3. the wrapping cloth wraps the front cavity and the rear cavity after being folded, and the wrapping cloth and the air bag are integrally sewn through the design of pre-sewing lines, so that the consistency of the folded air bag is realized, and the stability of the unfolding angle is ensured.

Drawings

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 described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view of the entire airbag assembly of the present application;

FIG. 2 is a block diagram of the knee airbag assembly of the present application in a non-installed, inflated condition;

FIG. 3 is a block diagram of the airbag assembly of the present application in an inflated condition during installation;

FIG. 4 is a schematic structural view of a symmetrical fabric sheet of the present application;

FIG. 5 is a schematic view of a symmetrical fabric panel sewn and a drawstring according to the present application;

FIG. 6 is a schematic view of the structure of the strip cloth of the present application;

FIG. 7 is a schematic view of a sewn vent according to the present application;

FIG. 8 is a block diagram of the wrapping cloth, front cavity and back cavity of the present application before folding when not inflated;

FIG. 9 is a view of the wrapping cloth of the present application wrapping the folded back portion and the folded back cavity;

FIG. 10 is a schematic structural view of the knee airbag device of the present application.

Description of reference numerals: 1. a front cavity; 11. a front panel; 12. a first abutting portion; 2. a rear cavity; 21. protecting the side panel; 22. a second abutting portion; 3. a communication panel; 31. an instrument panel; 4. a vent hole; 41. a gap; 5. symmetrical cloth pieces; 51. a line of symmetry; 52. pulling the belt; 6. a strip-shaped cloth piece; 61. bolt holes; 62. mounting a through hole; 63. a centerline; 7. wrapping cloth; 71. pre-sewing; 72. trepanning; 73. a free end; 8. a fold-back section; 81. a concave structure; 9. a housing; 91. an opening; 92. a cover plate; 93. a gas generator; 94. a bevel; 95. a bottom wall.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It should be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

The present embodiments provide a knee airbag assembly.

1-3, a knee airbag assembly comprising a front chamber 1 and a rear chamber 2 in a split configuration, the front chamber 1 being at least partially secured to the bottom of the vehicle's instrument panel 31 and communicating with the rear chamber 2, the airbag assembly being inflated and deployed with the front chamber 1 at least partially inflated prior to the rear chamber 2, the rear chamber 2 extending between the legs of the occupant and the instrument panel 31. The front cavity 1 and the rear cavity 2 are both provided with a communicating panel 3 pointing to the instrument panel 31, and the included angle formed between the communicating panel 3 of the front cavity 1 and the communicating panel 3 of the rear cavity 2 in the non-mounted inflation state is smaller than the included angle between the horizontal plane of the mounting point of the front cavity 1 and the instrument panel 31 corresponding to the leg of the passenger in the mounting state. It should be noted that the mounting point of the front cavity 1 is a position where the front cavity 1 is fixedly connected to the entire vehicle, that is, a mounting position of the gas generator 93.

Under the non-mounted inflation state, the included angle formed between the front cavity 1 communicating panel 3 and the rear cavity 2 communicating panel 3 is smaller than 90 degrees.

This application air pocket assembly is when not installing, namely, when not having the confined condition when aerifing, the contained angle that is between front chamber 1 and the back chamber 2 is less reaches the state parallel even, the air pocket assembly is installed when the instrument board 31 bottom to whole car, after aerifing, front chamber 1 is preferred to be aerifyd and is expanded and stretch out, an expansion initial stage control that is used for the air pocket assembly expandes position and angle, play the supporting role to the expansion of back chamber 2 simultaneously, back chamber 2 is at the expansion in-process, receive instrument board 31's restraint resistance, the contained angle increase of back chamber 2 and front chamber 1, expand along instrument board 31's trend, traditional knee gasbag design realizes the big corner of gasbag more easily and expandes, adapt to the molding of different whole cars.

As shown in fig. 2 and 3, the mounting point of the front cavity 1 is located on the side of the front cavity 1 communicating panel 3 far away from the passenger, the lower part of the rear cavity 2 communicating panel 3 is provided with a plurality of vent holes 4 arranged along the width direction of the vehicle, the side of the front cavity 1 communicating panel 3 close to the passenger is provided with vent holes 4 correspondingly arranged, the front cavity 1 communicating panel 3 and the rear cavity 2 communicating panel 3 are fixed along the vent holes 4, and the communicating panel 3 of the front cavity 1 and the rear cavity 2 is sewn along the periphery of the vent holes 4.

The mounting point of front chamber 1, namely, mounting position and air vent 4 of gas generator all are located the intercommunication panel 3 of front chamber 1, make front chamber 1 in the inflation process, and the air current is spout towards the opposite side that front chamber 1 is relative to intercommunication panel 3, just then gets into rear chamber 2 through the intercommunication position of front chamber 1 and rear chamber 2 to make front chamber 1 preferentially expand, and stably keep aerifing the bloated state.

As shown in fig. 2, 3, and 7, a first contact portion 12 is provided between the end of the front chamber 1 facing the occupant side and the end of the vent hole 4 facing the occupant side in the front chamber 1, and a second contact portion 22 that contacts the first contact portion 12 is provided below the vent hole 4 in the rear chamber 2. Further, the side edge of the front chamber 1 facing the occupant is flush with the lower end of the rear chamber 2, making the lengths of the first abutment portion 12 and the second abutment portion 22 the same. When the communicating panel 3 of the front chamber 1 and the rear chamber 2 is sewn along the periphery of the vent hole 4, a gap 41 is left between a sewing line on the periphery of the vent hole 4 and a side sewing line of the front chamber 1 facing the occupant as the first abutting portion 12, and a gap 41 is left between a sewing line of the vent hole 4 and a side sewing line of the lower end of the rear chamber 2 as the second abutting portion 22. The abutting action of the first abutting part 12 and the second abutting part 22 can make the rear cavity 2 lean up, which is convenient for the rear cavity 2 to expand with a large corner.

As shown in fig. 4 and 5, specifically, the rear cavity 2 is formed by folding the integral cloth piece relatively and then sewing the edges, the vent holes 4 are located at one end far away from the folding line, the extending lines of the vent holes 4 are parallel to the folding line of the cloth piece of the rear cavity 2, and the folding line divides the rear cavity 2 into the protective side panel 21 and the communicating panel 3.

In the embodiment of the application, the integrated cloth piece is a symmetrical cloth piece 5, a symmetrical line 51 of the symmetrical cloth piece 5 extends along the width direction of the vehicle, the width of the symmetrical cloth piece 5 is increased from the symmetrical line 51 to two side edges and then reduced, the symmetrical cloth piece 5 is folded along the symmetrical line 51 and the edges of the symmetrical cloth piece 5 are sewn to form a cavity of the rear cavity 2, and the symmetrical line 51 in the embodiment of the application is used as a folding line of the cloth piece of the rear cavity 2; when the airbag module is deployed in the mounted state, the rear chamber 2 extends from the line of symmetry 51 to the knees of the occupant, and the vent hole 4, which is the side away from the line of symmetry 51, is located below the lower leg of the occupant.

The rear cavity 2 still includes many interval distribution's stretching strap 52, many stretching straps 52 distribute along the direction of perpendicular to folding line, stretching strap 52 extends along the folding line direction of symmetry cloth piece 5, the protection side panel 21 and the intercommunication panel 3 of rear cavity 2 are connected respectively to the both sides limit of stretching strap 52, the side of stretching strap 52 is made on the protection side panel 21 and the intercommunication panel 3 of rear cavity 2, many stretching straps 52 carry out the expansion form of dispersion restraint rear cavity 2 from the upper portion to the lower part of rear cavity 2, stabilize the expansion form of rear cavity 2, be equipped with interval distribution's air vent 4 on the stretching strap 52.

As shown in fig. 6, specifically, the front cavity 1 is formed by folding the strip-shaped cloth 6 in half along a center line 63 of a long side of the strip-shaped cloth 6 and sewing edges, the center line 63 divides the front cavity 1 into the front panel 11 and the communication panel 3, an extending direction of the vent hole 4 of the communication panel 3 of the front cavity 1 is perpendicular to the center line 63, a bolt hole 61 is arranged at a mounting point of the front cavity 1, the bolt hole 61 is used for a bolt of a gas generator 93 to pass through, the vent hole 4 and the bolt hole 61 of the front cavity 1 are respectively located at two sides of the extending direction of the center line 63, that is, the vent hole 4 and the bolt hole 61 of the front cavity 1 are respectively located at two sides of a middle line of a short side of the strip-shaped cloth 6, a mounting through hole 62 for the gas generator 93 to pass through is arranged on the center line 63 of the strip-shaped cloth 6, and a connecting line of the mounting through hole 62 and the bolt hole 61 is parallel to the long side of the strip-shaped cloth 6.

The front cavity 1 comprises a plurality of layers of overlapped long-strip-shaped cloth pieces 6, and the folded long-strip-shaped cloth pieces 6 are used for wrapping the gas generator 93 together. The number of layers of the strip-shaped cloth piece 6 is set according to different output intensities of the generator, so that the front cavity 1 cannot be torn.

The embodiment of the application also discloses a knee air bag pre-folding assembly.

As shown in fig. 8 and 9, a knee airbag pre-folding assembly comprises the above-mentioned knee airbag assembly, a gas generator and a wrapping cloth, one end of the wrapping cloth 7 is sewn with the bolt hole 61, the other end is a free end 73, the free end 73 is provided with a sleeve hole 72 for sleeving on a bolt of the gas generator 93, the gas outlet end of the gas generator 93 is inserted into the front cavity 1, the bolt of the gas generator 93 extends out from the mounting point of the front cavity 1, the free end 73 of the wrapping cloth 7 surrounds the front cavity 1 and the rear cavity 2 which are wound and/or folded, and the sleeve hole 72 is sleeved on the bolt of the gas generator 93.

The present application also discloses a knee airbag device.

As shown in FIGS. 8 to 10, a knee airbag device comprises a case 9, a cover 92 and the above-mentioned pre-folding assembly, the case 9 is mounted on the bottom of an instrument panel 31 and is provided with an opening 91 facing the bottom of the vehicle and a bottom wall 95 facing the top of the vehicle, the cover 92 is provided with a reversible snap-fit opening 91, a gas generator 93 is bolted to the side of the bottom wall 95 remote from the occupant, and a front chamber 1 and a rear chamber 2 which are rolled and/or folded are disposed on the side facing the occupant in the case 9.

The case 9 has a long strip frame-shaped structure, and in the mounted state of the knee airbag device, the long side of the case 9 extends in the vehicle width direction, and a slope 94 is provided at the junction of the bottom wall 95 and the side facing the vehicle head, and the bolt of the gas generator 93 passes through and is fixed to the slope 94. One end of the cover plate 92 is fixed at the inclined plane 94 by a bolt of the gas generator 93, and the other end is fixed on the outer surface of the side part of the shell 9 after being fixedly wrapped on the opening 91 of the shell 9.

The middle part of the wrapping cloth 7 is sewn with the front cavity 1 between the vent holes 4 and the bolt holes 61 through a pre-sewing line 71, the pre-sewing line 71 can penetrate through the front panel 11 and the rear panel of the front cavity 1, and the pre-sewing line 71 is parallel to the folding line of the cloth piece of the rear cavity 2; the pre-stitches 71 tear during inflation of the inflator 93. The design of the pre-sewing line 71 sews the wrapping cloth 7 and the air bag assembly integrally, so that the folded air bag is consistent, and the stability of the unfolding angle is ensured.

The distance between the mounting point of the front cavity 1 and the pre-sewing line 71 is less than or equal to the width of the bottom wall 95 of the housing 9. The pre-stitched line 71 is located 55 + -10 mm from the air attachment point.

The front cavity 1 is folded back from the pre-sewing line 71 towards one side far away from the rear cavity 2 to form a folding-back part 8, a concave structure 81 facing a passenger is arranged on the folding-back part 8, the rear cavity 2 is wrapped by a wrapping cloth 7 after being wound and/or folded in the concave structure 81, and specifically, the upper part of the rear cavity 2 is folded and the lower part of the rear cavity 2 is folded and then is contained in the concave structure 81. The concave structure 81 is designed to generate a pushing force to the rear cavity 2 toward the lower leg of the occupant when the front cavity 1 is inflated and deployed, so that the rear cavity 2 is rapidly ejected.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A knee airbag assembly comprising a split front and rear chamber, said front chamber being at least partially secured to the underside of the vehicle dashboard and communicating with said rear chamber, said airbag assembly being inflated during deployment, said front chamber being at least partially inflated prior to the rear chamber, said rear chamber extending between the occupant's leg and the dashboard, characterized in that;

the front cavity and the rear cavity are both provided with a communicating panel pointing to an instrument panel, a mounting point of the front cavity is arranged on one side, far away from the passenger, of the front cavity communicating panel and is used for fixing the front cavity, a first abutting part is formed on one side, close to the passenger, of the front cavity communicating panel, and a second abutting part abutting against the first abutting part is arranged below the rear cavity communicating panel;

when the automobile is in a non-mounted inflation state, an included angle formed between the front cavity communicating panel and the rear cavity communicating panel is smaller than an included angle formed between a horizontal plane where a mounting point of the front cavity is located and an instrument panel corresponding to the leg of a passenger when the automobile is in a mounted state, the front cavity is fixed at the bottom of the instrument panel of the automobile through a fixing point of the front cavity and is in an inflation state, the first abutting part of the front cavity abuts against the second abutting part of the rear cavity, the rear cavity is pushed to deflect, and the front cavity is attached to the instrument panel of the automobile.

2. A knee airbag assembly according to claim 1 wherein the angle subtended by the front chamber communication panel and the rear chamber communication panel in the non-installed inflated condition is less than 90 °.

3. A knee airbag assembly according to claim 2, wherein a plurality of vent holes are provided in a lower portion of the rear chamber communication panel in a vehicle width direction, and a corresponding plurality of vent holes are provided in a side of the front chamber communication panel closer to the passenger, and the front chamber communication panel and the rear chamber communication panel are fixed along the vent holes.

4. The knee airbag assembly of claim 3, wherein the length of the first abutment is the same as the length of the second abutment.

5. A knee airbag assembly according to claim 3 or 4, wherein the rear chamber is formed by a unitary piece of cloth folded over opposite rear sewn edges, the vent hole is located at an end remote from a fold line, and an extension line of a plurality of the vent holes is parallel to the fold line, the fold line dividing the rear chamber into a protective side panel and the communication panel.

6. The airbag assembly of claim 5, wherein the rear cavity further comprises a plurality of spaced apart straps extending along the fold line, wherein two sides of the straps are connected to the protective side panel and the communication panel of the rear cavity, respectively, and the straps are provided with spaced apart vent holes.

7. The knee air bag assembly according to claim 5, wherein the front cavity is formed by folding an elongated cloth piece in half along a center line of a long side of the elongated cloth piece and sewing edges, the center line divides the front cavity into a front panel and a communication panel, an extending direction of the vent hole of the front cavity communication panel is perpendicular to the center line, a bolt hole is provided at a mounting point of the front cavity, the bolt hole is used for a bolt of a gas generator to pass through, the vent hole and the bolt hole of the front cavity are respectively located on both sides of the extending direction of the center line, and a mounting through hole for the gas generator to pass through is provided on the center line of the elongated cloth piece.

8. A knee air bag pre-fold assembly comprising the knee air bag assembly of any of claims 1-7, a gas generator, and a wrapping cloth, wherein a bolt hole is provided at a mounting point of the front cavity for a bolt of the gas generator to pass through, one end of the wrapping cloth is sewn to the bolt hole, the other end is a free end, the free end is provided with a sleeve hole for sleeving the bolt of the gas generator, the gas generator gas outlet end is inserted into the front cavity, the gas generator bolt extends from the front cavity mounting point, the free end of the wrapping cloth is wrapped around and/or folded behind the front cavity and the rear cavity, and the sleeve hole is sleeved on the bolt of the gas generator.

9. A knee airbag apparatus comprising a housing mounted on the instrument panel bottom, a cover provided with an opening toward the vehicle bottom and a bottom wall toward the vehicle top, the cover being turnably fastened to the opening, a pre-folding assembly according to claim 8, a bolt of the gas generator being mounted on the side of the bottom wall away from the occupant, the front and rear chambers being placed on the side of the housing facing the occupant after being rolled and/or folded.

10. The knee airbag device according to claim 9, wherein a plurality of vent holes are provided in a lower portion of the rear chamber communication panel in a vehicle width direction, the vent holes are provided in a corresponding arrangement in a side of the front chamber communication panel closer to the passenger, a middle portion of the wrapping cloth is sewn to the front chamber between the vent holes and the bolt holes by a pre-sewing line, the front chamber is folded back from the pre-sewing line toward a side away from the rear chamber to form a folded-back portion having a concave structure facing the passenger, and the rear chamber is wrapped by the wrapping cloth after being rolled and/or folded in the concave structure.

11. The knee airbag apparatus according to claim 10, wherein a distance between the mounting point of the front cavity and the pre-seam line is less than or equal to a bottom wall width of the case.

12. The knee airbag apparatus according to claim 11, wherein the pre-seam line is sewn through a front panel and a communication panel of the front cavity.

13. The knee airbag device according to claim 11, wherein an upper portion of the rear cavity is folded and a lower portion Z-folded and housed in the concave structure.