JP2008110706A - Airbag device for knee protection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag device for knee protection so formed that the movement of a steering column when it absorbs impact force is not obstructed even if mounted on the steering column. <P>SOLUTION: This airbag device for knee protection is disposed at the inside lower part of a column cover 14. A case 25 is mounted on the steering column 3. The steering column 3 comprises a moving side member 8 moving forward of a vehicle when an impact force acts thereon forward and an unmoved fixed side member 9. The case 25 is formed integrally with the synthetic resin column cover 14 with a sheet member 27F buried therein. In the case 25, the front portion forming the area interfered with the fixed side member 9 is formed in a flexible part 30 formed of the sheet member 27F, and the rear portion of the flexible part 30 is formed in a mounting part 36 formed to have rigidity higher than that of the flexible part 30 and used for mounting the case on the steering column 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an airbag device for knee protection, which is disposed on a lower side in a column cover that covers a steering column, and is configured by storing a folded airbag in a case attached to the steering column.

Conventionally, as a knee protection airbag device configured to store a folded airbag in a case attached to a steering column, there is a configuration in which a sheet metal case is attached to a column tube of a steering column. (For example, refer to Patent Document 1).
JP 2002-37003 A

  For example, the impact force (impact energy) is absorbed by moving the main shaft toward the front side of the vehicle along the axial direction by, for example, deforming the impact energy absorbing material when the impact force is applied to the front side. When the conventional knee protection airbag device is mounted on the main shaft of the steering column, which is possible, the knee protection airbag device moves together with the main shaft. There is a possibility that the case is arranged around the main shaft and interferes with a member attached to the column tube side that does not move even when the main shaft moves.

  The present invention solves the above-described problems, and an object of the present invention is to provide a knee protection airbag device that does not hinder the movement of the steering column when absorbing the impact force, even if it is attached to the steering column. .

A knee protection airbag device according to the present invention is provided on a lower side in a column cover that covers a steering column, a case attached to the steering column, an airbag folded and stored in the case, an airbag, An inflator that supplies inflation gas to the bag, and
A airbag device for knee protection configured to protrude from a column cover so that the airbag is deployed and inflated while allowing the inflation gas discharged from the inflator to flow in and protects the seated driver's knee,
The steering column includes a moving side member that moves toward the vehicle front side along the axial direction when an impact force is applied to the front side, and a stationary side member that does not move. Made to absorb power,
The inflator is housed on the rear side of the folded airbag in the case,
Case
As a flexible sheet material is embedded, it is molded integrally with a synthetic resin column cover,
A flexible portion that is arranged at least on the front side portion that is an area that interferes with the fixed side member during movement of the moving side member, and that is configured to extend rearward from the column cover and is made of a sheet material When,
A mounting portion for mounting the case to the steering column, which is molded on the rear side of the flexible portion with rigidity from the flexible portion;
It is characterized by comprising.

  In the knee protection airbag device of the present invention, the front portion of the case, which is an area that interferes with the stationary member during movement when absorbing the impact force, is made of a flexible sheet material. Since it is a flexible part, when the steering column moves the moving side member and absorbs the impact force, the case that moves with the movement of the moving side member interferes with the fixed side member. However, the portion of the flexible part is easily deformed, the resistance at the time of interference with the stationary member of the case can be reduced, and the steering column does not hinder the movement of the movable member and the main shaft. Can absorb impact force.

  Therefore, in the knee protection airbag device of the present invention, the structure attached to the steering column is configured not to prevent the movement of the steering column when absorbing the impact force.

  In the knee protection airbag device according to the present invention, an attachment portion that is more rigid than the flexible portion is disposed on the rear side of the flexible portion of the case, and the case causes the case to be steered. Since it is configured to be attached to the column, the reaction force at the time of deployment of the airbag can be received by the portion of the flexible portion between the attachment portion and the column cover. It can project smoothly. Furthermore, in the knee protection airbag device of the present invention, the case is made of a synthetic resin integrated with the column cover. Therefore, compared to the case of using a sheet metal case separate from the column cover as in the conventional case. Thus, the weight of the apparatus can be reduced and the number of components can be reduced.

  Further, in the knee protection airbag device of the present invention, the column cover covers the airbag opening for the airbag formed on the lower side of the case, and the portion to be broken is disposed around when the airbag projects. If the door part that is integrally formed when the column cover is molded is arranged so that it can be opened by breaking the door, the door part that covers the protruding opening of the airbag should also be integrated with the column cover. Therefore, it is not necessary to provide a separate door portion, which is preferable.

  Furthermore, in the knee protection airbag device having the above-described configuration, the mounting portion of the case is disposed in the inflator, and the steering column is used together with the inflator by using a mounting bolt for attaching the airbag and the inflator to the case. If it is configured to be attached to the inflator, the inflator and the case can be attached to the steering column simply by fastening the inflator mounting bolt to the steering column, reducing the number of man-hours for assembling the knee protection airbag device to the vehicle. Is preferable.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 5, an airbag device M for knee protection includes a column cover 14 that covers a steering column 3 in a steering wheel 1. It is arrange | positioned at the lower part side. The knee protecting airbag device M includes a case 25 attached to the steering column 3, an airbag 38 that is folded and stored in the case 25, and an inflator 43 that supplies inflation gas to the airbag 38. The inflated airbag 38 protrudes from a protruding opening O formed by pushing the front door portion 19 and the rear door portion 23 formed on the column cover 14 and is seated, and the driver MD is seated. It is comprised so that it may arrange | position to the front side of both knees K (KL, KR). Further, in the knee protecting airbag device M of the embodiment, the case 25 is formed integrally with the column cover 14.

  In the case of the embodiment, as shown in FIG. 1, the steering column 3 includes a main shaft 4 and a column tube 7 that covers the periphery of the main shaft 4, and the column tube 7 is on the inner peripheral side. It is comprised from the cylindrical inner member 8 arrange | positioned at the main shaft 4 side, and the outer member 9 arrange | positioned at the outer peripheral side of the inner member 8 (refer FIG. 3). As shown in FIG. 1, the steering column 3 of the embodiment is deformed when an impact force (impact energy) acts on the steering wheel 1 toward the front side of the vehicle. An impact force absorbing mechanism 5 that moves to the front side of the vehicle along the axial direction is disposed. When the driver MD moves forward and interferes with the steering wheel 1, the impact force absorbing mechanism 5 is deformed so as to move the steering wheel 1 toward the vehicle front side along the axial direction of the main shaft 4. It absorbs energy and relaxes the impact force on the driver MD.

  In the case of the embodiment, the inner member 8 in the column tube 7 moves to the vehicle front side along the axial direction together with the steering wheel 1 (main shaft 4) when the impact force absorbing mechanism 5 is deformed as a moving side member. The outer member 9 in the column tube 7 is configured as a stationary member so as not to move even when the impact force absorbing mechanism 5 is deformed. The knee protecting airbag device M of the embodiment is configured to attach the case 25 to the inner member 8 in the column tube 7. An adjustment mechanism 10 constituting a fixed side member such as a tilt mechanism or a telescopic mechanism is attached to the outer member 9 and disposed on the front side of the knee protecting airbag device M. Further, in the case of the embodiment, the case 25 is attached to the inner member 8 in a region that is an area that interferes with the adjusting mechanism 10 attached to the outer member 9 when moving when absorbing the impact force.

  The column cover 14 has a substantially rectangular tube shape so as to cover the steering column 3. In the case of the embodiment, the column cover 14 includes an upper cover 15 and a lower cover 16 that are divided into two vertically along the axial direction of the steering column 3. It is configured. In the case of the embodiment, the upper cover 15 and the lower cover 16 are made of a synthetic resin made of an olefin-based thermoplastic elastomer or the like. The upper cover 15 is attached to the column tube 7 of the steering column 3 at a portion (not shown), and the lower cover 16 is a portion of mounting pieces 31 and 35 (described later) of the case 25 and mounting bolts 45c of an inflator 43 (described later). Utilized, it is attached to a mounting bracket 8 a formed on the inner member 8. Further, the upper cover 15 and the lower cover 16 are formed by using a plurality of engagement claw portions and engagement recesses (not shown) provided on the lower edge side of the upper cover 15 and the upper edge side of the lower cover 16 over substantially the entire circumference. Are connected.

  The lower cover 16 includes a main body portion 17 and a case constituting portion 26 that is formed on the inner peripheral side of the main body portion 17 and forms the case 25.

  A rear surface (lower surface) 17a of a portion projecting from a surrounding instrument panel (hereinafter abbreviated as “instrument panel”) 12 in the main body portion 17 is formed as a substantially rectangular plate shape on a curved surface that rises rearward in the vehicle longitudinal direction. ing. As shown in FIGS. 8 and 9, the body portion 17 is provided with a planned breakable portion 18 that can be pushed and broken by the airbag 38 in the area extending from the lower surface 17 a side to the left side surface 17 b and the right side surface 17 c. Thus, a front door portion 19 and a rear door portion 23 that are opened when the airbag 38 is deployed and inflated so that a protrusion opening O can be formed are formed. The front door portion 19 is configured to dispose the planned fracture portion 18 around the periphery and open the rear edge side toward the front side, the lower door portion 20 disposed on the lower surface 17a side of the main body portion 17, and The left door portion 21 disposed on the left side surface 17b side of the main body portion 17 and the right door portion 22 disposed on the right side surface 17c side of the main body portion 17 are divided into three. The rear door portion 23 is configured to open the front edge side toward the rear side, and extends from the lower surface 17a side of the main body portion 17 to the left side surface 17b and the right side surface 17c on the rear side of the front door portion 19. Arranged in the area.

  The case component 26 includes a front member 28 disposed so as to extend rearward from the front edge side of the front door portion 19, a rear member 33 disposed so as to extend forward from the rear edge side of the rear door portion 23, and The sheet materials 27F and 27B that are flexible and restrained from being stretched are embedded integrally with the main body portion 17, respectively. In the case of the embodiment, the sheet materials 27F and 27B are mesh members made of polyamide resin such as 6,6-nylon.

  The front member 28 is formed along the left-right direction on the front edge side of the front door portion 19 and is disposed so as to protrude from the inner peripheral surface side of the main body portion 17 toward the steering column 3 side. A flexible portion 30 composed of a portion 29, a sheet material 27 </ b> F embedded in the front vertical wall portion 29 and extending from the front vertical wall portion 29, and a substantially rectangular plate disposed on the distal end side of the flexible portion 30 Shaped attachment piece 31. The rear member 33 is formed along the left-right direction on the rear edge side of the rear door portion 23 and is disposed so as to protrude from the inner peripheral surface side of the main body portion 17 toward the steering column 3 side. A vertical wall portion, and a substantially rectangular plate-shaped attachment piece portion that is embedded in the rear vertical wall portion and is disposed on the front end side of the sheet material 27B that extends from the rear vertical wall portion. . Each of the attachment pieces 31 and 35 constitutes an attachment portion 36 for attaching the case 25 to the steering column 3 by using the attachment bolt 45c of the inflator 43. Each of the attachment pieces 31 and 35 has an inflator 43, respectively. The insertion holes 31a and 35a through which the mounting bolts 45c can be inserted are formed. Each of the front side member 28 and the rear side member 33 covers the folded airbag 38 and the inflator 43 in the left and right width dimensions, and the left and right ends of the front side door portion 19 and the rear side door portion 23 in the left and right direction. The dimensions are set so as to be arranged at positions close to both edge sides. The case 25 has the folded airbag 38 and the inflator 43 so as to cover the front member 28 and the rear member 33 around the folded airbag 38 and the inflator 43 from the front to the rear through the upper part. The mounting pieces 31 and 35 are overlapped with each other so that the mounting bolts 45c of the inflator 43 are inserted through the insertion holes 31a and 35a. In the case of the embodiment, the sheet materials 27F and 27B are also embedded in the portions of the attachment pieces 31 and 35, respectively, and are disposed over substantially the entire area of the front side member 28 and the rear side member 33.

  As shown in the two-dot chain line in FIGS. 1 and 2 and FIG. 10, the airbag 38 is configured to be a horizontally long rectangular plate with a long left and right direction when the inflation is completed. The driver side wall 39 is disposed on the MD side, and the column side wall 40 is disposed on the column cover 14 side. The driver side wall portion 39 and the column side wall portion 40 are cut from a woven fabric such as polyester or polyamide yarn to have the same outer shape, and the outer peripheral edges are sewn together to form the airbag 38. Further, the column side wall portion 40 is formed with mounting holes 41 for projecting mounting bolts 45c (see FIGS. 3 and 4) of the inflator 43 housed in the airbag 38 at two locations along the left and right. (See FIG. 5). Further, as shown in FIG. 2, when the airbag 38 is deployed and inflated, the lower surface (rear surface) 17a of the lower cover 16 in the column cover 14 protruding rearward from the instrument panel 12 with respect to the knees KL and KR of the driver MD. It is comprised in the shape which can cover the lower side of the column cover 14 in the instrument panel 12, and the rear surface side of both right and left sides.

  As shown in FIGS. 3 to 5, the inflator 43 includes a cylinder-type main body 44 that is arranged so that the axial direction is along the left-right direction, and a substantially cylindrical diffuser 45 that holds the main body 44. Yes. In the case of the embodiment, the main body 44 is provided with a plurality of gas discharge ports 44a along the left and right at a position near the center in the left-right direction and on the front side when the vehicle is mounted, not shown. Lead wires are connected. The diffuser 45 is configured to open both ends in the left-right direction to cover the main body 44 over the entire region and to allow the expansion gas G to flow out from the openings 45a and 45b on both ends, as shown in FIGS. Thus, it is set as the structure which hold | maintains the main body 44 by crimping several places along the periphery of an axis | shaft. The diffuser 45 is provided with two mounting bolts 45 c for mounting the inflator 43 to the inner member 8 of the column tube 7 together with the airbag 38 and the case 25. As shown in FIGS. 3 and 4, each mounting bolt 45 c is fixed to a bracket 8 a formed on the inner member 8 with a nut 46. In the case of the embodiment, the inflator 43 is housed in the case 25 together with the airbag 38 so as to be disposed on the rear side of the folded airbag 38.

  Next, the mounting of the knee protection airbag apparatus M of the embodiment on a vehicle will be described. First, an airbag in which the inflator 43 is housed inside by causing the mounting bolt 45c to protrude from the mounting hole 41. 38 is folded. Thereafter, the folded airbag 38 and the inflator 43 are arranged between the front vertical wall portion 29 and the rear vertical wall portion 34 of the case component 26 in the lower cover 16, and the front members 28 and the rear members 33 The front bolt 28c of the inflator 43 is protruded from the insertion holes 31a and 35a of the mounting pieces 31 and 35 so that the front member 28 and the rear member 33 are surrounded by the folded airbag 38 and the inflator 43. The airbag 38 and the inflator 43 are arranged around the folded airbag 38 and the inflator 43 so as to cover from the front through the upper part to the rear, and the airbag 38 and the inflator 43 are accommodated in the case 25, and the airbag 38 and the inflator 43 are also accommodated. The case 25 and the lower cover 16 are assembled. Thereafter, the lower cover 16 is attached to the mounting bracket 8a disposed on the inner member 8 of the steering column 3 already attached to the vehicle, the mounting bolt 45c is fixed to the nut 46, and attached to the steering column 3, and the upper cover 15 is attached to the steering column. If attached to the column 3, the knee protection airbag apparatus M can be mounted on the vehicle together with the column cover 14.

  Then, after mounting on the vehicle, if an operation signal is input to the main body 44 of the inflator 43 via a lead wire (not shown), the expansion gas G is discharged from the gas discharge port 44a of the inflator 43, and the expansion gas G is As shown in FIG. 5, the air flows into the airbag 38 through the openings 45 a and 45 b on the left and right ends of the diffuser 45. Then, the inflating airbag 38 pushes open the front door portion 19 and the rear door portion 23 of the column cover 14, protrudes downward from the protruding opening O, and the two-dot chain line in FIGS. As shown, the expansion will be completed. In the knee protection airbag apparatus M of the embodiment, since the diffuser 45 opens both the left and right sides, the inflation gas G discharged from the inflator 43 extends in the airbag 38 along the left-right direction. The airbag 38 that flows into and inflates first pushes open the left door part 21 and the right door part 22 of the front door part 19 and the left and right side parts of the rear door part 23, and then The lower door part 20 of the front door part 19 and the lower part of the rear door part 23 are pushed open, and the front door part 19 and the rear door part 23 are pushed open to the front and rear sides to open the projection. O is formed, and the airbag 38 projects downward from the projecting opening O.

  In the embodiment, when the driver MD interferes with the steering wheel 1 and largely presses the steering wheel 1 forward, the steering column 3 operates the impact force absorbing mechanism 5 so that the main shaft 4 Along with the inner member 8 in the column tube 7, it is configured to move forward toward the vehicle front side along the axial direction to absorb the impact force. In the knee protection airbag device M according to the embodiment, the front side portion, which is an area where the case 25 interferes with the outer member 9 as the stationary member during movement when absorbing the impact force, is flexible. Therefore, when the steering column 3 moves the inner member 8 as the moving side member to absorb the impact force, the inner member 8 is moved. Even if the moving case 25 interferes with the outer member 9 as shown in FIG. 10, the portion of the flexible portion 30 is easily deformed, and the case 25 interferes with the outer member 9. The resistance at the time can be reduced, and the impact force can be absorbed by the steering column 3 without hindering the movement of the inner member 8 and the main shaft 4. When the case 25 interferes with the outer member 9, since the airbag 38 is not stored in the case 25 in a folded state, the resistance at the time of interference is small.

  Therefore, in the airbag apparatus M for knee protection of the embodiment, the structure attached to the steering column 3 is configured not to prevent the movement of the steering column 3 when absorbing the impact force.

  Further, in the knee protection airbag device M of the embodiment, the attachment portion 36 that is molded more rigidly than the flexible portion 30 is disposed on the rear side of the flexible portion 30 in the case 25, and the attachment portion 36, since the case 25 is attached to the steering column 3, the airbag 38 is deployed by the portion of the flexible portion 30 between the attachment portion 36 and the column cover 14 (the main body portion 17 of the lower cover 16). The reaction force of time can be received, and the airbag 38 can be smoothly protruded downward from the column cover 14. In the knee protection airbag device M of the embodiment, the case 25 is configured to cover the periphery of the airbag 38 and the inflator 43 from the front through the upper part to the rear, and the left and right sides are opened. In the vicinity of the left and right openings of 25, the left and right side portions of the front door portion 19 and the rear door portion 23 (portions formed on the left side surface 17b and the right side surface 17c of the lower cover 16) are arranged close to each other. Therefore, it is not necessary to receive a reaction force from the airbag 38 that inflates at the left and right portions of the case 25. Even if the case 25 has a configuration in which the left and right sides are opened, the airbag 38 can be connected to the column cover. It can project smoothly downward from 14. Further, in the knee protection airbag device M of the embodiment, the attachment portion 36 is configured such that the two attachment pieces 31 and 35 in which the sheet materials 27F and 27B are embedded are overlapped with each other. Thus, the attachment strength is increased, and the case 25 can be firmly attached to the attachment bracket 8 a of the inner member 8 by the attachment bolt 45 c of the inflator 43. Furthermore, in the knee protection airbag apparatus M of the embodiment, the case 25 is made of a synthetic resin integrated with the column cover 14 (lower cover 16), so that the case made of sheet metal separate from the column cover as in the past. Compared with the case of using the device, it is possible to reduce the weight of the device and the number of components.

  Furthermore, in the knee protection airbag apparatus M of the embodiment, the lower door 16 constituting the column cover 14 is provided with the front door portion 19 that covers the projection opening O of the airbag 38 formed on the lower side of the case 25, and the rear door portion 19. Since the side door portion 23 is integrally disposed, a member as an airbag cover provided with the door portion may not be separately disposed. Of course, if such a point is not taken into consideration, a member as an airbag cover provided with a door portion may be separately provided.

  In the knee protection airbag device M of the embodiment, the device can be assembled by storing the airbag 38 and the inflator 43 that are folded in advance in a portion of the lower cover 16 that constitutes the case 25. If the lower cover 16 storing the airbag 38 and the inflator 43 is attached to the steering column 3, the knee protection airbag device M can be mounted on the vehicle simultaneously with the attachment of the lower cover 16 to the steering column 3. It is possible to reduce assembly man-hours, assembly man-hours, and costs.

  In the knee protection airbag device M according to the embodiment, the attachment portion 36 of the case 25 is attached to the steering column 3 together with the inflator 43 using the attachment bolt 45c of the inflator 43. By simply fastening the mounting bolt 45c to the mounting bracket 8a of the steering column 3, the inflator 43 and the case 25 can be attached to the steering column 3, and the number of assembling steps for the knee protection airbag device M can be reduced. It is possible and preferable. Of course, if this point is not taken into consideration, the mounting portion 36 of the case 25 may be mounted on the steering column 3 side separately from the inflator 43.

  The knee protection airbag device M according to the embodiment includes a front member 28 and a rear member 33 in which two sheet members 27F and 27B are embedded as a case component 26 that constitutes the case 25. However, the shape of the case component is not limited to this. For example, as shown in FIG. 11, only the front member 28 having the same configuration as the front member 28 described above, The sheet material 27F is embedded, the rear member 33A is configured not to embed the sheet material, and the rear vertical wall portion 34A and the attachment piece portion 35A are continuously disposed with the hinge portion 33a interposed therebetween. The case 25A may be formed by using the case component 26A configured as described above. Further, as shown in FIG. 12, the case component 26B having no rear member is used as shown in FIG. Te, may be formed in the case 25B. In the case component 26B, the sheet material 27FB has a length dimension that can cover the entire area of the folded airbag 38 and the inflator 43 from the front to the upper side and from the rear to the rear, and the front member 28B has a front and rear intermediate portion. The attachment piece portion 31 is disposed on the front end of the sheet material FB, and the engagement protrusion 49 that can be fitted in the engagement recess 48 formed on the rear edge side of the rear door portion 23 is disposed on the front end side of the sheet material FB. Yes.

1 is a schematic side view showing a portion in the vicinity of a steering column on which a knee protection airbag device according to an embodiment of the present invention is mounted. It is the schematic front view seen from the vehicle back side which shows the use condition of the airbag apparatus for knee protection of embodiment. It is a schematic longitudinal cross-sectional view of the vehicle front-back direction which shows the use condition of the airbag apparatus for knee protection of embodiment. It is a general | schematic expanded longitudinal cross-sectional view of the vehicle front-back direction of the airbag apparatus for knee protection. It is a schematic sectional drawing of the VV site | part of FIG. It is a schematic front view of the airbag used for the airbag apparatus for knee protection of embodiment. It is a schematic perspective view which shows the lower cover in the column cover used for the airbag apparatus for knee protection of embodiment. FIG. 8 is a schematic plan view of the lower cover of FIG. 7. It is a schematic partial perspective view which shows the open state of the front door part and rear door part which are formed in the lower cover of FIG. FIG. 2 is a schematic cross-sectional view in the vehicle front-rear direction showing a state where the airbag is completely inflated in the knee protection airbag device of the embodiment. It is a schematic sectional drawing of the vehicle front-back direction which shows the modification of a case. It is a schematic sectional drawing of the vehicle front-back direction which shows the modification of a case.

Explanation of symbols

1 ... Steering wheel,
3 ... Steering column,
4 ... Main shaft,
5 ... Shock absorbing mechanism,
7 ... Column tube,
8 ... Inner member (moving side member),
9: Outer member (fixed member),
10 ... adjustment mechanism,
14 ... Column cover,
16 ... Lower cover,
18 ... planned to break,
19 ... front door,
23: Rear door,
25 ・ 25A ・ 25B ... Case,
27F, 27B ... sheet material,
30 ... flexible part,
31, 35 ... mounting piece,
36 ... mounting part,
38 ... Airbag,
43 ... Inflator,
45c ... mounting bolts,
K (KL, KR) ... knees,
MD ... Driver,
M: Air bag device for knee protection.

Claims (3)

A case disposed on the lower side of a column cover that covers the steering column and attached to the steering column, an airbag that is folded and stored in the case, and an inflator that supplies inflation gas to the airbag And a configuration comprising:
The airbag is a knee protection airbag device configured to protrude from the column cover so that the airbag is deployed and inflated while allowing the inflation gas discharged from the inflator to flow in and protects the seated driver's knee. And
The steering column includes a moving side member that moves toward the front side of the vehicle along the axial direction when an impact force is applied to the front side, and a stationary side member that does not move, and when the moving side member moves It is configured to absorb impact force,
The inflator is housed on the rear side of the folded airbag in the case,
The case is
As the sheet material having flexibility is embedded, the column cover made of synthetic resin is integrally formed,
The sheet member is arranged at least at a front side portion that is an area that interferes with the stationary member when the movable member moves, and is configured to extend rearward from the column cover. A flexible part;
A mounting portion for mounting the case to the steering column, which is molded on the rear side of the flexible portion and having rigidity from the flexible portion;
A knee protection airbag device, comprising:   The column cover covers an opening for protruding the airbag formed on the lower side of the case, and when the airbag protrudes, it can be opened by breaking a planned breaking portion disposed around the airbag. The knee protection airbag device according to claim 1, wherein the knee protection airbag device is provided with a door portion formed integrally when the column cover is formed.   The mounting portion of the case is disposed on the inflator and is configured to be mounted on the steering column together with the inflator using a mounting bolt for mounting the airbag and the inflator to the case. The knee protection airbag device according to claim 1 or 2.

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