Knee airbag

Abstract

The present application relates to a knee bladder (50) comprising a cushioning portion comprising overlapping sheets (52, 54) interconnected along a peripheral connection to define an inflatable volume of the knee bladder. The sheets are interconnected within a peripheral connection (60) along one or more internal connections defining an inflatable chamber within the inflatable volume. The knee airbag further includes a tether (80) connected to an outer surface of the cushioning portion at spaced apart locations. The tether has a length that is shorter than a distance between locations on the buffer portion that are connected to the tether. The tether is configured to tension and cause a bend to be formed in the cushioning portion in response to inflation of the cushioning portion.

Description

Technical Field

[0001] The present disclosure relates to a device for assisting in protecting an occupant of a vehicle when an event such as a vehicle collision occurs. More specifically, the present disclosure relates to a knee airbag. Background Art

[0002] It is known to deploy an inflatable vehicle occupant protection device (such as an airbag) when an event (such as a vehicle collision or rollover) in which occupant protection is desired occurs. The airbag is part of a conventional vehicle occupant protection device that includes sensors and a source of inflation fluid (such as an inflator). When an event in which it is desired to deploy the airbag is sensed, the source of inflation fluid is actuated and generates an inflation fluid that causes the airbag to inflate, so that it deploys in the vehicle occupant compartment to assist in protecting the vehicle occupant.

[0003] A particular type of inflatable vehicle occupant protection device is a knee airbag. The knee airbag is typically stored in a housing mounted in the lower portion of the instrument panel in the footwell area. The knee airbag can be inflated to a deployed state in which the knee airbag is located between the occupant's legs and the instrument panel to assist in protecting the vehicle occupant from injury, particularly injury to the occupant's legs. Summary of the Invention

[0004] The knee airbag includes a cushioning portion that includes overlapping panels that are interconnected along a peripheral connection portion to define an inflatable volume of the knee airbag. The panels are interconnected along one or more internal connection portions within the peripheral connection portion, and the internal connection portions define inflatable chambers within the inflatable volume. The knee airbag also includes a tether that is connected to an outer surface of the cushioning portion at spaced-apart locations. The tether has a length that is shorter than the distance between the locations on the cushioning portion to which the tether is connected. The tether is configured to be tensioned in response to inflation of the cushioning portion and to cause a bend to form in the cushioning portion.

[0005] According to one aspect, the chambers can be configured to extend along a longitudinal dimension of the cushioning portion. The knee airbag can be configured such that when inflated, the longitudinal dimension of the cushioning portion extends vertically in the vehicle.

[0006] According to another aspect, the tether can be configured to form a bend that is transverse to the longitudinal dimension of the cushioning portion.

[0007] According to another aspect, the cushioning portion can include a front panel configured to face the occupant and a rear panel configured to face the instrument panel. The outer surface to which the tether is connected can be the outer surface of the rear panel.

[0008] According to another aspect, the bend in the cushioning portion can be configured such that the cushioning portion conforms to the contour of the instrument panel.

[0009] According to another aspect, the bent portion in the buffer portion may define a first section and a second section of the buffer portion that extend angularly relative to each other on opposite sides of the bent portion. The bent portion may be configured such that the first section conforms to a first portion of the instrument panel and the second section conforms to a second portion of the instrument panel.

[0010] According to another aspect, the first portion and the second portion of the instrument panel may be generally flat surfaces that extend angularly relative to each other.

[0011] According to another aspect, the first portion and the second portion of the instrument panel may be portions of a curved surface of the instrument panel.

[0012] According to another aspect, the bent portion may be configured to be positioned at a location where the first portion and the second portion of the instrument panel meet.

[0013] According to another aspect, the buffer portion may have a generally rectangular configuration, and the internal connecting portion may connect the front sheet and the rear sheet to each other to form a chamber.

[0014] According to another aspect, the buffer portion may have a one-piece woven structure, in which the front sheet and the rear sheet are woven simultaneously. The peripheral connecting portion and the internal connecting portion may be defined by mutually woven portions of the front sheet and the rear sheet.

[0015] According to another aspect, the buffer portion may have an assembled structure, in which the front sheet and the rear sheet are separately woven sheets and are connected to each other along the peripheral connecting portion and the internal connecting portion by at least one of sewing, welding, and bonding.

[0016] According to another aspect, the tether may be a first tether, and the bent portion may be a first bent portion. The knee airbag may further include a second tether that is connected to an outer surface of the buffer portion at spaced positions. The second tether may have a length that is shorter than the distance between the positions on the buffer portion to which the second tether is connected. The second tether may be configured to be tensioned when the buffer portion inflates and to form a second bent portion spaced apart from the first bent portion in the buffer portion.

[0017] According to another aspect, the first bent portion and the second bent portion in the buffer portion may be configured such that the buffer portion conforms to the contour of the instrument panel.

[0018] According to another aspect, the first bent portion and the second bent portion in the buffer portion may define a first section, a second section, and a third section of the buffer portion that extend angularly relative to each other. The bent portion may be configured such that the first section conforms to a first portion of the instrument panel, the second section conforms to a second portion of the instrument panel, and the third section conforms to a third portion of the instrument panel.

[0019] According to another aspect, a knee airbag module may include a knee airbag, an inflator for inflating the knee airbag, and a housing for supporting the knee airbag and the inflator. The housing may include an opening through which the knee airbag is deployed, and the housing may be configured to be mounted in a vehicle instrument panel in a footrest area of the vehicle.

[0020] According to another aspect, a vehicle safety system may include: a knee airbag module; a sensor configured to sense the occurrence of an event for which deployment of the knee airbag is desired; and a controller configured to actuate the inflator to deploy the knee airbag in response to the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The foregoing and other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art by reference to the following description of the invention, in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout the drawings, and in which:

[0022] Figure 1 is a side view schematically showing a vehicle safety system including a device for assisting in protecting an occupant of a vehicle.

[0023] Figure 2 is Figure 2 a side view of the knee airbag of

[0024] Figure 3 is a rear perspective view of a knee airbag forming part of a vehicle safety system according to an exemplary configuration.

[0025] Figure 4 is Figure 2 a front view of the knee airbag of

[0026] Figure 5 is a side view of a knee airbag according to another exemplary configuration. DETAILED DESCRIPTION

[0027] Figure 1 There is shown a vehicle safety system 10 for assisting in protecting an occupant 14 of a vehicle 12. The safety system 10 includes a device in the form of a knee airbag module 30, which includes an inflatable knee airbag 50, an inflator 32 for inflating the knee airbag 50, and a housing 34 for supporting the knee airbag and the inflator. The knee airbag module 30 is configured to be attached to an instrument panel 20 of the vehicle 12 adjacent to or proximate a footrest area 22 of the vehicle.

[0028] In Figure 1In the illustrated embodiment, the knee airbag module 30 is a passenger knee airbag module configured to help protect an occupant 14 on the passenger side seat 16 of the vehicle 12. Those skilled in the art will understand that the systems and devices 10 disclosed herein can be adapted for a driver-side or center-seated vehicle occupant (not shown) or an occupant in the rear row of the vehicle 12, such as in the second row, third row, etc. of the vehicle (not shown).

[0029] The knee airbag 50 has a stored state, as Figure 1 shown by the dashed line as 50’ in which the knee airbag is folded and placed within the housing 34. The housing 34 helps to accommodate and support the knee airbag 50 and the inflator 32 within the instrument panel 20. The knee airbag module 30 is hidden within the instrument panel 20, for example, by a cover 36 that is in the form of a door or panel that is a part of the module itself, a part of the instrument panel, a trim piece of the instrument panel, or a combination of these components.

[0030] The inflator 32 is capable of being actuated to supply inflation fluid to the inflatable volume of the knee airbag 50 to deploy the knee airbag to Figure 1 the inflated state shown by the solid line in. The inflator 32 can be of any known type, such as a solid propellant or stored gas design, or a hybrid design that implements both solid propellant and stored gas. The safety system 10 includes a sensor schematically shown as 36 for sensing an event (such as a collision) for which it is desired to inflate the knee airbag 50. The inflator 32 is operatively connected to the sensor 36 via a lead 38.

[0031] The knee airbag 50 can be made of any suitable material, such as woven nylon (e.g., nylon 6-6), and can be manufactured in any suitable manner. For example, the knee airbag 50 can include one or more sheets or panels of material. If more than one sheet or panel is used, the sheets or panels can be connected to each other by known means (such as stitching, ultrasonic welding, thermal bonding, or adhesives) to form the knee airbag 50. The knee airbag 50 can be uncoated, coated with a material (such as airtight polyurethane), or laminated with a material (such as an airtight film). Thus, the knee airbag 50 can have an airtight or substantially airtight construction. Those skilled in the art will understand that alternative materials (such as polyester yarn) and alternative coatings (such as silicone) can also be used to construct the knee airbag 50.

[0032] Figures 2-4The knee airbag 50 is shown. As shown in these figures, the knee airbag 50 has a simple construction, where the front sheet 52 is configured to face the occupant 14, and the rear sheet is configured to engage the instrument panel 20. The front sheet and the rear sheets 52, 54 are interconnected around a peripheral connection portion 60 (e.g., a sewn, adhesively bonded, or welded seam). Within the perimeter, the sheets 52, 54 may be interconnected at one or more internal connection portions 62, such as a direct sheet-to-sheet connection via a sewn, adhesively bonded, or welded seam, or interconnected via a tether 64 that is connected to both the front sheet and the rear sheet and then sewn, adhesively bonded, or welded together. In the case of the tether 64, it may have a simple construction, such as an elongate rectangular construction. Regardless of the construction, the internal connection portion 62 helps to limit the expansion of the sheets 52, 54, control the inflation thickness of the knee airbag 50 as measured between the front sheet and the rear sheet, and define the inflatable chamber 64 of the knee airbag.

[0033] In a particular configuration, the knee airbag 50 may have a so-called one-piece woven (OPW) construction, where the overlapping sheets 52, 54 are woven simultaneously and intertwined with each other to form the peripheral connection portion 60 and the internal connection portion 62. The OPW knee airbag 50 including the connection portions 60, 62, and the inflatable chamber 64 can be formed in a single weaving step.

[0034] As Figures 2-4 shown, the internal connection portions 62 are essentially longitudinal, which means they are configured to be located in a vertical plane extending longitudinally along the vehicle 12. From the perspective of the seated occupant 14, the internal connection portions 62 extend vertically in the manner shown, for example, Figure 4 in. The vertically extending internal connection portions 62 help to define the vertically extending inflatable chamber 64 of the knee airbag 50. This construction is simple because it implements overlapping flat sheets 52, 54 with the peripheral connection portion 60 extending around its perimeter. Additionally, compared to more complex constructions, connecting the front sheet and the rear sheets 52, 54 with the internal connection portion 62 to control the thickness of the airbag and provide the inflatable chamber 64 is simple and inexpensive, where the internal connection portion is formed by a simple connection (e.g., sewing, adhesive, or welding) between the front sheet and the rear sheet or a generally uniform tether (e.g., elongate rectangular).

[0035] The cushion portion 70 of the knee airbag 50 (i.e., the interconnected front sheet and rear sheets 52, 54 and the internal connection portion (seam / tether)) has a natural inflation configuration, the nature of which may be similar to an air mattress. That is, in its natural inflated state, the cushion portion 70 may be generally rectangular (see, for example, Figure 4), and has a generally uniform thickness controlled by the internal connection portion 62. This configuration represents one of the simplest ways to achieve a buffer portion with a generally uniform thickness. However, the buffer portion 70 can deviate from the illustrated rectangular configuration without adding any significant complexity to the design. For example, the buffer portion 70 can have a tapered (e.g., trapezoidal) configuration or a circular (e.g., oval) configuration.

[0036] The distance between the instrument panel 20 and the occupant 14 can depend on factors such as the size of the occupant, the fore-and-aft position of the vehicle seat 16, and the architecture of the vehicle 12. To help ensure that the knee airbag 50 provides the highest level of protection to the occupant, it is important that the airbag deploys along the contour of the surface of the instrument panel 20. However, the contour of the instrument panel 20 can be complex, having curved surfaces and / or flat surfaces extending at different angles / directions. For example, in Figure 1 the instrument panel 20 has a first surface 24 that extends toward the occupant 14 at a first angle that is generally upward and rearward in the vehicle 12. The second surface 26 intersects the first surface 24 and extends upward and rearward toward the vehicle roof 28 at a second angle in a generally steeper direction.

[0037] To configure the buffer portion 70 of the knee airbag 50 to conform to the contour of the instrument panel 20 along the first and second surfaces 24, 26, a more complex configuration may be required with modified front and rear sheets, additional curved / tapered side sheets, and a modified and / or more complex tether configuration. However, advantageously, the knee airbag 50 includes one or more external tethers 80 that control the shape of the buffer portion 70 such that it simply conforms to the contour of the instrument panel 20 without unnecessary complexity.

[0038] Referring to Figures 2-4 , the tether 80 is large, rectangular, and spans the width of the buffer portion 70 or a significant portion of that width. The tether 80 is connected to the rear sheet 54 along a tether connection portion 82 that extends across the tether and the buffer portion 70 in the width direction. The tether connection portion 82 can be, for example, a sewn connection, an adhesive connection, or a welded connection.

[0039] The tether 80 has a length L1 that is longer than the length of the rear sheet 54 between the tether connection portions 82, which length is Figure 2shorter than the sum of lengths L2 and L3 shown in [FIG.]. Due to this length difference, when the knee airbag 50 inflates, the tether 80 becomes taut, which restricts the rear sheet 54 from fully assuming the normal flat configuration of the cushion portion 70. Thus, in the fully inflated and deployed state of the knee airbag 50, the tether 80 causes a bend 72 to form in the cushion portion 70. The first and second sections 74, 76 of the cushion portion 70 are defined on opposite sides of the bend 72 and extend away from the bend at an angle A.

[0040] The position of the bend 72, the respective lengths of the cushion sections 74, 76, and the angle A between the cushion sections are determined by the length of the tether 80 and the position of the tether connection portions 82. Generally, the position of the bend 72 occurs at or near the midpoint between the tether connection portions 82. The angle A depends on the difference between the tether length L1 and the distance L2+L3 between the tether connection portions 82. The tether length L1 is shorter than the tether connection portion distance L2+L3 by a defined ratio. Otherwise, no bend would form. Taking this into account, it can be seen that the bend angle A can be decreased, i.e., made steeper or sharper, by decreasing the tether length L1 and / or increasing the tether connection portion distance L2+L3. Conversely, the bend angle A can be increased, i.e., made flatter, by increasing the tether length L1 and / or decreasing the tether connection portion distance L2+L3.

[0041] Advantageously, through the configuration of the tether 80, the knee airbag 50 can be configured to conform to the contour of the instrument panel 20. As Figure 1 shown, the bend 72 created by the tether 80 causes the first section 74 of the cushion portion 70 to conform to the first part 24 of the instrument panel 20, and the second section 76 of the cushion portion to conform to the second part 26 of the instrument panel. The bend 72 is positioned at the location where the first and second parts 24, 26 meet each other. The manner in which the sections 74, 76 of the cushion portion 70 conform to the respective parts 24, 26 of the instrument panel 20 does not necessarily correspond exactly or precisely to the contour of the instrument panel. However, the cushion portion 70 conforms to the contour of the instrument panel 20 in a manner sufficient to maintain a close enough spacing to ensure that the knee airbag 50 can fully inflate and deploy without being blocked or otherwise impeded, such as by an occupant 14 positioned close to the instrument panel during deployment.

[0042] Additionally, the contour of the instrument panel 20 does not necessarily include distinct, substantially flat parts 24, 26 that extend at an angle relative to each other. For example, referring to Figure 3, the instrument panel can have a curved profile represented by 20' as shown by the dashed line. In this case, the portions covered by sections 74, 76 can be portions 24', 26' of the curved profile of the instrument panel 20'. In this case, the portions 24', 26' of the curved profile of the instrument panel 20' can be defined or marked by the curved portion 72 in the buffer portion 70.

[0043] Figures 1-4 The exemplary configuration of the knee airbag 50 shown in shows a buffer portion 70 having a single tether 80 configured to form a single curved portion 72 in the buffer portion. Additional tethers forming additional curved portions can be implemented. For example, referring to Figure 5 , the knee airbag 100 can include a buffer portion 102 having a first curved portion and a second curved portion 104, 106 formed by a first tether and a second tether 110, 112 respectively. The curved portions 104, 106 define a first section, a second section, and a third section 120, 122, 124 of the buffer portion 102. For example, this can enable the buffer portion 102 to conform to the profile of the instrument panel 130. In this configuration, the first section 120 can conform to the profile of the first part 140 of the instrument panel 130. The second section 122 can conform to the profile of the second part 142 of the instrument panel 130. The third section 124 can conform to the profile of the third part 144 of the instrument panel 130.

[0044] Similar to Figures 1-4 the exemplary configuration, for Figure 5 the exemplary configuration of the knee airbag 100 in, the manner in which the sections 120, 122, 124 of the buffer portion 102 conform to the corresponding parts 104, 142, 144 of the instrument panel 130 does not necessarily correspond exactly or precisely to the profile of the instrument panel. However, the buffer portion 102 conforms to the profile of the instrument panel 130 in a manner sufficient to maintain a close enough spacing to ensure that the knee airbag 100 can be fully inflated and deployed without being blocked or otherwise hindered, such as by an occupant positioned close to the instrument panel during deployment.

[0045] Advantageously, through the configuration of the tethers 110, 112, the knee airbag 100 can be configured to conform to the profile of the instrument panel 20. As Figure 5As shown, the bends 104, 106 created by the tethers 110, 112 cause the first section 120 of the cushion portion 102 to conform to the first part 140 of the instrument panel 130, the second section 122 of the cushion portion 102 to conform to the second part 142 of the instrument panel, and the third section 124 of the cushion portion 102 to conform to the third part 144 of the instrument panel. The bend 104 is located at the position where the first part and the second part 140, 142 meet each other. The bend 106 is located at the position where the second part and the third part 142, 144 meet each other.

[0046] The manner in which the sections 120, 122, 124 of the cushion portion 102 conform to the respective parts 140, 142, 144 of the instrument panel 130 does not necessarily correspond exactly or precisely to the profile of the instrument panel. However, the cushion portion 102 conforms to the profile of the instrument panel 130 in a manner sufficient to maintain a close enough spacing to ensure that the knee airbag 100 can fully inflate and deploy without being blocked or otherwise impeded, such as by an occupant positioned close to the instrument panel during deployment.

[0047] Additionally, the profile of the instrument panel 20 does not necessarily include distinct, substantially flat and angularly extending parts 140, 142, 144 relative to each other. For example, referring to Figure 5 , the instrument panel can have a curved profile as shown by the dashed line and denoted as 130'. In this case, the parts covered by the sections 120, 122, 124 can be the parts 140', 142', 144' of the curved profile of the instrument panel 130'. In this case, the parts 140', 142', 144' of the curved profile of the instrument panel 130' can be defined or marked by the bends 110, 112 in the cushion portion 102.

[0048] Examples of the present invention have been described above. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of describing the present invention, but those of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A knee airbag, comprising: A cushioning portion including overlapping sheets that are interconnected along a peripheral connection portion to define an inflatable volume of the knee airbag and are interconnected along one or more internal connection portions within the peripheral connection portion, the internal connection portions defining inflatable chambers within the inflatable volume; And Tethers connected to an outer surface of the cushioning portion at spaced positions, wherein the tethers have a length shorter than the distance between the positions on the cushioning portion to which the tethers are connected; Wherein the tethers are configured to be tensioned in response to inflation of the cushioning portion and to cause a bending portion to be formed in the cushioning portion.

2. The knee airbag according to claim 1, wherein the internal connection portions and chambers are configured to extend along a longitudinal dimension of the cushioning portion, and wherein the knee airbag is configured such that when inflated, the longitudinal dimension of the cushioning portion extends vertically in a vehicle.

3. The knee airbag according to claim 2, wherein the tethers are configured to form a bending portion transverse to the longitudinal dimension of the cushioning portion.

4. The knee airbag according to claim 1, wherein the cushioning portion includes a front sheet configured to face an occupant and a rear sheet configured to face a dashboard, and wherein the outer surface to which the tethers are connected is the outer surface of the rear sheet.

5. The knee airbag according to claim 1, wherein the bending portion in the cushioning portion is configured such that the cushioning portion conforms to the contour of the dashboard.

6. The knee airbag according to claim 5, wherein the bending portion in the cushioning portion defines a first section and a second section of the cushioning portion that extend angularly relative to each other on opposite sides of the bending portion, and wherein the bending portion is configured such that the first section conforms to a first portion of the dashboard and the second section conforms to a second portion of the dashboard.

7. The knee airbag according to claim 6, wherein the first portion and the second portion of the dashboard are substantially flat surfaces that extend angularly relative to each other.

8. The knee airbag according to claim 6, wherein the first portion and the second portion of the dashboard include portions of a curved surface of the dashboard.

9. The knee airbag according to claim 6, wherein the bending portion is configured to be positioned at a location where the first portion and the second portion of the dashboard meet.

10. The knee airbag according to claim 4, wherein the cushioning portion has a generally rectangular configuration, and wherein the internal connection portions interconnect the front sheet and the rear sheet to form the chambers.

11. The knee airbag according to claim 4, wherein the cushioning portion has a one-piece woven structure, wherein the front sheet and the rear sheet are woven simultaneously, and the peripheral connection portions and the internal connection portions are defined by mutually woven portions of the front sheet and the rear sheet.

12. The knee airbag according to claim 4, wherein the buffer portion has an assembled structure, wherein the front sheet and the rear sheet are separately woven sheets, and are connected to each other along the peripheral connection portion and the internal connection portion by at least one of sewing, welding, and adhesion.

13. The knee airbag according to claim 1, wherein the tether is a first tether and the bent portion is a first bent portion, and wherein the knee airbag further includes a second tether that is connected to the outer surface of the buffer portion at a spaced-apart position, wherein the second tether has a length shorter than the distance between the positions on the buffer portion to which the second tether is connected, and wherein the second tether is configured to be tensioned when the buffer portion is inflated and form a second bent portion spaced apart from the first bent portion in the buffer portion.

14. The knee airbag according to claim 13, wherein the first bent portion and the second bent portion in the buffer portion are configured such that the buffer portion conforms to the contour of the instrument panel.

15. The knee airbag according to claim 14, wherein the first bent portion and the second bent portion in the buffer portion define a first section, a second section, and a third section that extend angularly relative to each other in the buffer portion, wherein the bent portions are configured such that the first section conforms to a first part of the instrument panel, the second section conforms to a second part of the instrument panel, and the third section conforms to a third part of the instrument panel.

16. A knee airbag module, comprising: The knee airbag according to claim 1; An inflater configured to inflate the knee airbag; And A housing configured to support the knee airbag and the inflater, the housing including an opening through which the knee airbag is deployed; Wherein the housing is configured to be installed in a vehicle instrument panel in a footrest area of the vehicle.

17. A vehicle safety system, comprising: The knee airbag module according to claim 16; A sensor configured to sense the occurrence of an event that is expected to deploy the knee airbag; And a controller configured to actuate the inflater in response to the sensor to deploy the knee airbag.

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