Knee airbag, airbag device and airbag manufacturing method

Abstract

The present invention provides a knee airbag for knee protection, an airbag device and an airbag manufacturing method. The knee airbag provided by the present invention is communicated with a gas generator and includes: an airbag main piece which is bent and sewn at the head and tail to form the upper surface and the lower surface of the knee airbag, and the width of the airbag main piece matches that of the instrument panel; and two airbag side pieces which are symmetrically sewn on both sides of the airbag main piece and form a sealed cavity with the airbag main piece, and an opening for communicating the sealed cavity with the gas generator is arranged on one of the airbag side pieces, wherein the shape of the airbag side piece is set according to the structural parameters of the instrument panel.

Description

Technical Field

[0001] The present invention relates to the field of automotive airbags, and particularly to a knee airbag for knee protection, an airbag device and a method for manufacturing an airbag. Background Art

[0002] A knee airbag device is generally installed at the lower part of an automotive instrument panel, in front of the occupant's knees and calves. The airbag in the knee airbag device matches the shape of the lower part of the automotive instrument panel after being inflated, so as to meet the protection requirements for the occupant's calves and knees. Currently, existing knee airbags generally adopt a two-dimensional design composed of two pieces of fabric front and back. The fabric of the airbag on the side close to the lower part of the automotive instrument panel is wrinkled to shorten the length above the airbag, and the fabric on the side close to the occupant's leg remains unchanged, making the fabric lengths on both sides of the airbag inconsistent. Relying on this inconsistency, the inflated airbag forms a "banana shape" to match the lower half of the automotive instrument panel. Or additional external straps need to be added to the surface of the airbag to enable the airbag to fit the lower instrument panel.

[0003] The above existing knee airbags have the following two disadvantages: 1. The sewing manufacturing process for the airbag to achieve a "banana shape" inflated state and match the lower part of the instrument panel is relatively troublesome, difficult to automate, and the matching degree is also difficult to adjust according to different vehicle models; 2. Since the "concave" shape inflated state needs to be achieved by shortening the fabric of one side of the airbag through wrinkling, the design of the existing knee airbag can only match the horizontal straps (vertical straps will affect the formation of wrinkles). And the horizontal straps will affect the flow rate of the air to a certain extent and will delay the inflation time of the airbag to a certain extent. Therefore, there are greater limitations when used in some vehicle models with a small interior space and very strict requirements for the airbag arrival time. Summary of the Invention

[0004] Therefore, in order to overcome the above disadvantages of the prior art, the present invention provides a knee airbag for knee protection and an airbag device.

[0005] The present invention provides a knee airbag, which is communicated with a gas generator and includes: a main airbag sheet, which is bent and sewn at the head and tail to form the upper surface and the lower surface of the knee airbag, and the width of the main airbag sheet matches the instrument panel; and two side airbag sheets, symmetrically sewn on both sides of the main airbag sheet, and form a sealed cavity with the main airbag sheet. An opening for communicating the sealed cavity with the gas generator is provided on one of the side airbag sheets, wherein the shape of the side airbag sheet is set according to the structural parameters of the instrument panel.

[0006] In one embodiment, the main airbag sheet is provided with a bending mark line, and this bending mark line makes the length of the lower surface of the main airbag sheet on the side close to the occupant greater than the length of the upper surface on the side close to the instrument panel.

[0007] In one embodiment, the airbag side piece includes a first portion near the bending marking line, a second portion away from the bending marking line, and a third portion connecting the first portion and the second portion, wherein the width of the third portion > the width of the first portion > the width of the second portion.

[0008] In one embodiment, the knee airbag further includes a pull belt disposed in the sealed cavity, connecting the upper surface and the lower surface.

[0009] In one embodiment, the width of the pull belt is smaller than the width of the airbag side piece.

[0010] In one embodiment, the airbag main piece is respectively provided with sewing marks for sewing the pull belt at corresponding positions on the upper surface and the lower surface, and the length of the sewing mark located on the lower surface is greater than the length of the sewing mark located on the upper surface.

[0011] In one embodiment, the sewing marks are arranged perpendicular or parallel to the bending marking line of the airbag main piece.

[0012] In one embodiment, the pull belt is provided with a plurality of ventilation holes.

[0013] The present invention also provides an airbag device for knee protection, including: a housing having a receiving cavity; a knee airbag disposed in the receiving cavity for allowing inflation gas to flow in, protruding from the receiving portion toward the rear side of the vehicle, and simultaneously expanding to protect the knees of passengers; and a gas generator disposed in the receiving cavity and communicating with the knee airbag for inflating the knee airbag, wherein the knee airbag is the above-mentioned knee airbag.

[0014] The present invention provides an airbag manufacturing method, including:

[0015] Cutting out an airbag main piece, two airbag side pieces and a plurality of pull belts on a blank;

[0016] Providing a bending marking line and sewing marks for a plurality of pull belts on the airbag main piece;

[0017] Bending the airbag main piece along the bending marking line into a U shape so that the sewing marks on the main piece are in corresponding upper and lower positions;

[0018] Sewing the pull belt located in the middle of the airbag, and then gradually sewing the pull belts located on both sides of the airbag;

[0019] Sewing the head and tail of the folded airbag main piece to form a closed ring-shaped semi-finished product;

[0020] Sewing the two airbag side pieces to both ends of the closed ring-shaped semi-finished product respectively to form a knee airbag.

[0021] Compared with the prior art, the advantages of the present invention are as follows: The knee airbag is a three-dimensional airbag on all four sides of the front, rear, left, and right. The shape of the airbag after inflation and expansion is determined by the shape of the airbag side panel, and the shape of the airbag side panel is set according to the structural parameters of the instrument panel, which can more accurately achieve the matching of the lower part of the instrument panel and improve the adaptability of the airbag device to different vehicle models. Moreover, such a setting also reduces the sewing difficulty of the airbag, saves costs and man-hours, and is easy to realize the automation of manufacturing production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram showing the protection of an occupant by the inflated airbag of the airbag device in an embodiment of the present invention;

[0023] Figure 2 is an exploded view of the airbag device in an embodiment of the present invention;

[0024] Figure 3 is a schematic structural diagram of the knee airbag in an embodiment of the present invention;

[0025] Figure 4 is a schematic flat view of the airbag main panel in an embodiment of the present invention;

[0026] Figure 5 a and Figure 5 b are schematic flat views of the airbag side panel in an embodiment of the present invention;

[0027] Figure 6 is a schematic diagram showing the stitching of the airbag main panel and the pull belt in an embodiment of the present invention;

[0028] Figure 7 a to 7e are schematic flat views of the internal pull belt of the airbag in an embodiment of the present invention;

[0029] Figure 8 is a top view of the knee airbag in an embodiment of the present invention;

[0030] Figure 9 is Figure 8 a cross-sectional view taken along the A-A plane in;

[0031] Figure 10 is a top view of the knee airbag in another embodiment of the present invention; and

[0032] Figure 11 is Figure 10 a cross-sectional view taken along the B-B plane in. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0034] As Figure 1And Figure 2 As shown in Figure 2 , the airbag device 100 provided in this embodiment includes a housing 12, a knee airbag 2, and a gas generator 9.

[0035] The housing 12 can accommodate the airbag 2 and the gas generator 9 in a folded state. The edge of the housing 12 matches the corresponding opening at the lower part of the vehicle instrument panel. The housing 12 can be made of a rigid material such as a metal material and is arranged on the back side of the instrument panel 3 with the rear side of the vehicle as the opening side. The housing 12 is supported on a reinforcing member such as an instrument panel reinforcing member (not shown) via a bracket. The housing 12 has an opening through which the airbag 2 can pass. When the airbag expands, the housing 2 cracks from the opening under the airbag expansion pressure above a predetermined value, causing the airbag to eject from the opening. The housing 2 is provided with a cover 13 for closing the opening at the opening. In one embodiment, the housing 12 may further include a mounting bracket 14, and the knee airbag device can be fixed to the corresponding designed position on the vehicle body through the mounting bracket 14.

[0036] Figure 3 is the shape presented after the knee airbag 2 is inflated. The overall shape of the knee airbag 2 is a "banana type" structure with a wide and flat top, a concave middle part, and a narrowed root. The top of the knee airbag 2 can extend to the passenger's knee position, and the width is slightly larger than the distance between the knees of the occupant's legs, providing effective protection for driving safety. The knee airbag 2 includes an airbag main sheet 6 and two airbag side sheets 7.

[0037] The airbag main sheet 6 forms the upper and lower surfaces of the knee airbag by bending and sewing the head and tail, and the width of the airbag main sheet matches the instrument panel. As Figure 4 shown, the length of the ad segment of the main sheet generally matches the leg space at the lower part of the instrument panel to meet the protection of the occupant's legs. The lengths of the cf / be segments at both ends of the main sheet are equal and match the length dimension of the housing 12. The airbag main sheet 6 is provided with a bending marking line 15, which makes the length of the lower surface of the airbag main sheet close to the occupant greater than the length of the upper surface close to the instrument panel. The distances L1 and L2 from the bending marking line 15 to the cf / be ends of the main sheet 6 can be adjusted according to the highest knee point position of the occupant in the vehicle. And because the "banana type" shape with both ends upturned needs to be formed after the airbag is deployed, the length of the side of the main sheet facing the occupant's knee is greater than the side facing the lower part of the instrument panel, that is, L1 > L2.

[0038] The airbag side sheets 7 are symmetrically sewn on both sides of the airbag main sheet 6 and form a sealed cavity with the airbag main sheet 6. As Figure 5As shown in a, an opening 16 is provided on an airbag side panel to connect the closed cavity with the gas generator so as to expose the connector of the generator. In order to prevent excessive gas from escaping, the diameter of the opening 16 will be 2 to 4 mm smaller than the diameter of the connector of the generator. The shape of the airbag side panel 7 is set according to the structural parameters of the instrument panel 3. The shapes of the two airbag side panels 7 determine the degree of matching between the shape of the airbag after expansion and the lower part of the instrument panel 3. The airbag side panel 7 includes a first part 71 close to the bending mark, a second part 72 away from the bending mark, and a third part 73 connecting the first part 71 and the second part 72. The width of the third part 73 is greater than the width of the first part 71 and the width of the second part 72.

[0039] The width of the airbag side panel 7 can be adjusted according to the required thickness after the airbag 2 is deployed, and the curvature of the airbag side panel matches the shape of the lower half of the car dashboard, which determines the degree of "banana-shaped" tilting of the airbag after it is filled. The perimeter of the airbag side panel 7 is equal to the length of the corresponding single side of the main panel 6. The perimeter S1 of the airbag side panel 7 is equal to the length of the main panel cb, and the perimeter S2 of the other side panel is equal to the length of the main panel ef.

[0040] The gas generator 9 is disposed in a preset area at the base of the airbag, and is connected to the knee airbag 2, and is used to inflate the knee airbag 2. The generator 9 can be inserted into the airbag through a preset opening at the bottom of the airbag, and the gas generator 9 can also include mounting bolts. The airbag 2 and the gas generator 9 are fixed to the housing 12 together by the mounting bolts.

[0041] In the above-mentioned knee airbag and airbag device, the knee airbag is a three-dimensional airbag with four sides, front, back, left, and right. The shape of the airbag after inflation is determined by the shape of the airbag side piece, and the shape of the airbag side piece is set according to the structural parameters of the instrument panel, which can more accurately match the lower part of the instrument panel and improve the adaptability of the airbag device to different models. Moreover, such a setting also reduces the difficulty of sewing the airbag, saves costs and working hours, and is easy to realize manufacturing automation.

[0042] In another embodiment, Figure 6 As shown, the knee airbag 2 further includes a drawstring 8 disposed in the sealed cavity. The drawstring 8 connects the upper surface and the lower surface formed by the airbag main sheet 6. The width of the drawstring 8 determines the local thickness between the upper and lower surfaces of the airbag 2 after it is filled, and can be defined separately according to requirements. Figures 8 - 9 As shown, the knee airbag 2 can be provided with a plurality of drawstrings 8 longitudinally on the airbag main sheet 6. The drawstrings 8 are sewn on the upper and lower surfaces of the airbag interior formed by bending the airbag main sheet 6, and the closed cavity inside the knee airbag is divided into a plurality of chambers 10. The number and volume of the inflatable chambers are determined by the arrangement position and width of the drawstrings 8. Figure 7As shown in Figures a to 7e, at least one ventilation hole is provided on each drawstring 8, enabling the air flow in each chamber 10 to communicate with each other and maintaining the internal pressure balance in the sealed cavity. The size and quantity of the ventilation holes can be adjusted according to actual protection performance requirements. The thickness of each chamber can be adjusted by regulating the width dimension of the drawstring 8 to meet different needs. The width of the drawstring 8 is less than the width of the side piece 7 to form an internal concave surface, thereby preventing the leg 4 from slipping out of the protection area of the airbag. Each drawstring 8 can include two sewn edges at both ends, which are respectively sewn on the upper and lower surfaces inside the airbag. The bending degree and shape of the drawstring are consistent with the horizontal projection of the side piece.

[0043] In the above knee airbag and airbag device, drawstrings can also be provided to accurately adjust the shape of the airbag, improving the matching degree between the airbag and the lower part of the instrument panel as well as the knees of the passengers.

[0044] In one embodiment, a number of longitudinal sewing marks 11 for the drawstrings 8 are also provided on the main piece 6. The number of sewing marks 11 is the same as the number of required drawstrings 8 and can vary according to actual requirements. Each sewing mark 11 consists of two segments on both sides of the bending marking line 15 distributed at the same horizontal position. The length of the L1 side is greater than that of the L2 side. Generally, the number of sewing marks 11 ranges from 1 to 10, and in this embodiment, it is 5. The overall arrangement of the drawstrings 8 is longer in the middle and shorter at both ends as the airbag narrows. The distance between every two sewing marks 11 can be adjusted according to the local thickness requirements after the airbag is filled. As Figure 4 shown, a certain distance L3 needs to be reserved from the sewing mark 11 to the bending marking line 15 of the main piece to ensure that the sewing of the drawstring 8 will not hinder the air flow between the chambers. The length of L3 is usually adjusted within the range of 50 to 200 mm. For the same reason, to ensure the smooth conduction of the gas in the airbag, the length of the distance L4 from the drawstring sewing mark to the edge of the airbag main piece 6 generally also remains within the range of 50 to 200 mm. The length of the drawstring sewing mark 11 is equal to the corresponding sewing side length of the corresponding drawstring 8. As Figure 7 shown in Figure e, the sewing mark L5 is equal to the length of the gh section of the drawstring, and the sewing mark L6 is equal to the length of the ij of the drawstring.

[0045] In another embodiment, as Figures 10 - 11 shown, the drawstring 8 can be set to be parallel to the bending marking line 15, that is, the arrangement mode of the drawstring 8 is changed from longitudinal to transverse. At the same time, the chamber 10 is also changed from longitudinal to transverse. In this embodiment, 4 drawstrings can be used. Similarly, the length of the middle drawstring is greater than that of the drawstrings on both sides. Since the direction of the drawstring determines the air flow transmission path, the deployment attitude and filling time of the airbag will change greatly. The airbag arrival time of the longitudinal drawstring is about 2 ms earlier than that of the transverse drawstring airbag.

[0046] In the above-mentioned knee airbag and airbag device, the arrangement direction of the pull belt can also be adjusted as needed, so as to shorten the time for the airbag to expand in place.

[0047] In one embodiment, the present invention also provides an airbag sewing method

[0048] Step 1: Cut out the airbag main piece 6, two airbag side pieces 7 and several pull belts 8 on the blank.

[0049] Step 2: Set the bending marking line 15 and the sewing marks 11 of several pull belts 8 on the airbag main piece 6.

[0050] Step 3: Bend the airbag main piece 6 along the bending marking line 15 into a U shape, so that the pre-defined pull belt sewing marks 11 on the main piece achieve corresponding upper and lower positions.

[0051] Step 4: Sew the longer pull belts located in the middle of the airbag, and then gradually sew the shorter pull belts located on both sides of the airbag.

[0052] Step 5: Sew the head and tail of the folded airbag main piece together to form a closed-loop semi-finished product.

[0053] Step 6: Sew the two airbag side pieces 7 to both ends of the above-mentioned closed-loop semi-finished product respectively to form a knee airbag as Figure 3 shown.

[0054] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and variations can still be made, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A knee airbag, which is connected to a gas generator, and is characterized in that, Comprising: A main airbag sheet, bent and sewn at the head and tail to form the upper and lower surfaces of the knee airbag, and the width of the main airbag sheet matches that of the instrument panel; And Two side airbag sheets, symmetrically sewn on both sides of the main airbag sheet, forming a sealed cavity with the main airbag sheet, and an opening for communicating the sealed cavity with the gas generator is provided on one of the side airbag sheets, wherein, the shape of the side airbag sheet is set according to the structural parameters of the instrument panel, the main airbag sheet is provided with a bending marking line, and this bending marking line makes the length of the lower surface of the main airbag sheet on the side close to the occupant greater than the length of the upper surface on the side close to the instrument panel, the bending degree of the side airbag sheet matches the lower part shape of the instrument panel, the side airbag sheet includes a first part close to the bending marking line, a second part far from the bending marking line, and a third part connecting the first part and the second part, and the width of the third part > the width of the first part > the width of the second part, the knee airbag further includes a pull belt arranged in the sealed cavity, connecting the upper surface and the lower surface.

2. The knee airbag according to claim 1, characterized in that, The width of the pull belt is smaller than the width of the side airbag sheet.

3. The knee airbag according to claim 1, characterized in that, Sewing marks for sewing the pull belt are respectively arranged at corresponding positions on the upper surface and the lower surface of the main airbag sheet, and the length of the sewing mark on the lower surface is greater than the length of the sewing mark on the upper surface.

4. The knee airbag according to claim 3, characterized in that, The sewing mark is arranged perpendicular or parallel to the bending marking line of the main airbag sheet.

5. The knee airbag according to any one of claims 2 - 4, characterized in that, A plurality of ventilation holes are arranged on the pull belt.

6. An airbag device for knee protection, characterized in that, Comprising: A housing having a receiving cavity; A knee airbag arranged in the receiving cavity, for allowing inflation gas to flow in, protruding from the receiving part towards the rear side of the vehicle, and simultaneously unfolding and inflating to protect the knees of the passengers; and A gas generator arranged in the receiving cavity, communicating with the knee airbag, for inflating the knee airbag, wherein, the knee airbag is the knee airbag according to any one of claims 1 to 5.

7. An airbag manufacturing method, characterized in that, Comprising: Cutting out a main airbag sheet, two side airbag sheets and a plurality of pull belts on a blank, and the bending degree of the side airbag sheet matches the lower half shape of the instrument panel; Arranging a bending marking line and sewing marks for several pull belts on the main airbag sheet; this bending marking line makes the length of the lower surface of the main airbag sheet on the side close to the occupant greater than the length of the upper surface on the side close to the instrument panel; Bending the main airbag sheet along the bending marking line into a U shape, so that the sewing marks on the main sheet achieve corresponding upper and lower positions; Sewing the pull belt located in the middle of the airbag, and then gradually sewing the pull belts located on both sides of the airbag; Sewing the head and tail of the folded main airbag sheet to form a closed ring-shaped semi-finished product; Sewing the two side airbag sheets to both ends of the closed ring-shaped semi-finished product respectively to form a knee airbag, wherein, the knee airbag is the knee airbag according to any one of claims 1 to 5.

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