JP6287670B2 - Knee bolster - Google Patents

Description

  The present invention relates to a knee bolster that is deformed by an input of a load from an occupant's knee and absorbs an impact on the knee.

  The knee bolster is disposed in front of an occupant's knee sitting on the front seat of the vehicle, and has a function of protecting the occupant's knee by plastic deformation of the knee bolster when the vehicle collides head-on. Patent Document 1 discloses a knee bolster made of a blow molded article.

WO2012 / 137892

  The blow molded body can be formed by blowing air into the cavity of the split mold in a state where the molten parison is arranged in the split mold. Since the blow molded body is formed using a split mold, a parting line is formed on the outer periphery thereof. In blow molded products used for knee bolsters, a parting line may be placed on the load input surface where the input of load from the knee is input. In this case, the blow molded product tends to break at the parting line. is there.

  As a solution to such a problem, a method of preventing a crack in the parting line by providing a thick portion along the parting line can be considered. However, when such a method is adopted, as shown in FIG. 1 (a), the initial load increases due to the reaction force due to the thick wall, and then the blow molded body receives the buckling of the thick wall portion. It turned out that the problem that the load which can be produced falls rapidly arises.

  This invention is made | formed in view of such a situation, and provides the knee bolster which can suppress the generation | occurrence | production of the crack of a blow molded object and can absorb the impact to a knee appropriately.

  According to the present invention, the knee bolster is formed of a blow molded body that is deformed by an input of a load from an occupant's knee and absorbs an impact on the knee, and the blow molded body is a load to which the load is input. A parting line is formed on the input surface, and a thick portion is provided along the parting line. An initial striking portion to which the load is first applied is provided on the load input surface. A knee wall is provided with a thin wall adjacent to the striking portion, and the thin wall is thinner than a total thickness obtained by adding up the thicknesses of both side surfaces of the blow molded body at the initial striking portion.

  The present inventors have intensively studied to solve the problem of an increase in initial load caused by providing a thick part in the parting line, and are adjacent to the initial striking part where the load from the knee is first input. By providing a thin wall, as illustrated in FIG. 1B, it is possible to suppress an increase in initial load and a decrease in load due to buckling, and for this reason, an impact on the knee is appropriately absorbed. As a result, the present invention has been completed.

Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.
Preferably, the thin wall is provided substantially parallel to the input direction of the load.
Preferably, the initial hitting portion is a flat surface.
Preferably, a region around the initial hitting portion is inclined with respect to the initial hitting portion.
Preferably, the blow molded body has lateral groove ribs on a right side surface and a left side surface, and the lateral groove ribs are formed so that side walls thereof are substantially parallel to the input direction of the load. At least one has not reached the load input surface.

It is a graph which shows an example of the relationship between the deformation | transformation amount of a knee bolster, and a load. The example of attachment of the knee bolster 1 of this invention is shown. It is a perspective view of knee bolster 1 of one embodiment of the present invention. It is the perspective view seen from another angle of the knee bolster 1 of FIG. It is a left view of the knee bolster 1 of FIG. It is a front view of the knee bolster 1 of FIG. It is a right view of the knee bolster 1 of FIG. (A)-(b) is an AA end view and a BB end view in Drawing 3 and Drawing 6, respectively. (A)-(b) shows the blow molding method of the site | part corresponding to Fig.8 (a). (A)-(b) shows the blow molding method of the site | part corresponding to FIG.8 (b).

  Hereinafter, embodiments of the present invention will be described. Various characteristic items shown in the following embodiments can be combined with each other.

<Example of installation of knee bolster 1>
First, an example of mounting the knee bolster 1 according to this embodiment will be described with reference to FIG. FIG. 2 shows a state in which the knee bolster 1 shown in FIGS. 3 to 10 is attached to the automobile 100 as an impact absorber.

  An automobile 100 shown in FIG. 2 includes an occupant compartment 103 including a front seat 102 for an occupant including a driver 101, and a meter 104 is located on a side surface of the handle 105. The steering wheel 105 is connected to a steering column (not shown), and a steering support member that supports the steering column is supported on the inner wall surface of the vehicle body and provided in the vehicle width direction. The knee bolster 1 of the present embodiment is attached to the driver's seat side with the steering column sandwiched on both sides of the steering column. However, since the space on both sides of the steering column is vertically long in relation to the installation space of other vehicle components (meter 104, navigation device, air conditioner, etc.), each of the drivers 101 in the vertically long space The knee bolster 1 is attached so as to be adjacent to the knee 3. Thus, when the automobile 100 receives an impact, the knee 3 of the driver 101 comes into contact with each knee bolster 1, absorbs the impact by the knee bolster 1, and reduces the impact applied to the knee 3. FIG. 2 shows the knee bolster 1 on the driver's seat side, but an elbow support member is attached to the passenger seat side so as to be adjacent to the knee of the passenger seated in the passenger seat, similarly to the driver seat side. Will be.

<Configuration of knee bolster 1>
A knee bolster 1 according to an embodiment of the present invention will be described with reference to FIGS.
The knee bolster 1 includes a blow molded body 9 that is deformed by the input of a load F from the occupant's knee 3 and absorbs an impact on the knee 3.

  The blow molded body 9 includes a front surface 9f adjacent to the knee 3 and serving as a load input surface, a rear surface 9r facing the front surface 9f, an upper surface 9u connecting the front surface 9f and the rear surface 9r, a bottom surface 9b, a right side surface 9m, and a left side surface 9l. It consists of. In addition, in this specification, up and down, left and right, and front and rear are described from the viewpoint of the occupant.

  An initial striking portion 5 to which a load F from the knee 3 is first applied is provided on the front surface 9f. The initial striking portion 5 has a flat surface, which prevents the blow molded body 9 from falling sideways. Moreover, the area | region around the initial hit | damage part 5 inclines with respect to the initial hit | damage part 5, and is C surface or R surface. If there is a surface substantially parallel to the surface of the initial striking portion 5 in the vicinity of the initial striking portion 5, an increase in the initial load becomes remarkable due to the synergistic effect of the surface and the thick portion 19, By increasing the area around the initial striking portion 5 with respect to the initial striking portion 5 as in this embodiment, an increase in the initial load can be suppressed.

  6, 9 and 10, since the blow molded body 9 is formed by blow molding using split molds 11 and 12 that open and close in the left-right direction, the front surface 9f, the top surface 9u, the back surface 9r, The parting line PL is formed over the bottom surface 9b. In FIG. 6, the parting line PL is highlighted and displayed with a thick line. Further, burrs 15 are formed along the parting line PL. The burr 15 can be removed after the blow molded body 9 is taken out from the divided molds 11 and 12.

  As shown in FIG. 9A, the split molds 11 and 12 have compression parts 11b and 12b outside the pinch-off parts 11a and 12a, and the melt parisons 13 and 14 are sandwiched between the compression parts 11b and 12b. As a result, a part thereof moves in the cavity direction of the divided molds 11 and 12, and a thick portion 19 is formed as shown in FIG. 9B. For this reason, the thick part 19 is formed along the parting line PL. The thick part 19 is a part where the thickness is thicker than the adjacent part, and the thickness is not particularly defined, but is preferably 1.1 times or more the thickness of the part adjacent to the thick part 19, 1.2 times or more is more preferable. Although the upper limit of the thickness of the thick portion 19 is not particularly defined, for example, it is preferably not more than 3 times the thickness of the portion adjacent to the thick portion 19 and more preferably not more than 2 times. This is because if the thick portion 19 is too thick, the increase in the initial load becomes remarkable.

  As shown in FIG. 10 (a), the split molds 11 and 12 have other compression portions 11c and 12c inside the pinch-off portions 11a and 12a at the portion where the thin wall 7 is formed. As shown in FIG. 10 (b), the melt parisons 13 and 14 are sandwiched between the compression portions 11c and 12c, so that the melt parisons 13 and 14 are compressed and the thin wall 7 is formed. At this time, a part of the molten parisons 13 and 14 moves in the cavity direction of the divided molds 11 and 12 to form the thick portion 19.

  The thin wall 7 is formed at a position adjacent to the initial striking portion 5 so as to extend substantially parallel to the input direction of the load F. As described above, as a result of providing the thick portion 19 along the parting line PL, as shown in FIG. 1A, an increase in initial load and a decrease in load due to subsequent buckling are likely to occur. In the present embodiment, by arranging the thin wall 7 adjacent to the initial striking portion 5, as shown in FIG. 1B, it is possible to suppress the initial load and suppress the occurrence of buckling. ing. Further, in the waveform of FIG. 1A, the initial load is large, so that the knee 3 is easily damaged. However, in the waveform of FIG. 1B, the initial load is relatively low and the load is applied over a wide range of deformation. Is substantially constant, it is possible to prevent the knee 3 from being damaged without applying an excessive impact to the knee 3. The thin wall 7 is configured to be thinner than the total thickness obtained by adding the thicknesses of both side surfaces of the blow molded body 9 in the initial hitting portion 5. The thickness of the thin wall 7 is preferably 80% or less, more preferably 50% or less of the total thickness. Although the minimum of the thickness of the thin wall 7 is not prescribed | regulated in particular, For example, 10% or more of the said total thickness is preferable. This is because if the thin wall 7 is thinner than this, molding becomes difficult.

  The blow molded body 9 has lateral groove ribs 9c on the right side surface 9m and the left side surface 9l. The lateral groove rib 9c is recessed from each of the right side surface 9m and the left side surface 9l toward the parting line PL (that is, toward the hollow portion). Further, in order to increase the proof stress against the load F from the knee 3, the lateral groove rib 9c is formed so that the side wall thereof is substantially parallel to the input direction of the load F. Three lateral groove ribs 9c are formed on each of the right side surface 9m and the left side surface 9l, and the two upper and lower lateral groove ribs 9c are formed so as to extend from the back surface 9r to the front surface 9f. On the other hand, the central lateral groove rib 9c reaches the back surface 9r but does not reach the front surface 9f. With such a configuration, the blow molded body 9 is easily deformed in the vicinity of the initial striking portion 5, and an increase in the initial load is further suppressed.

  On the back surface 9r of the blow molded body 9, there are provided mounting projections 9g for mounting the blow molded body 9 to an object to be mounted. The object to be attached can be welded to the steering support member, or can be fixed to other parts by screwing or welding. As another configuration for attaching the blow molded body 9 to an attachment object, for example, one disclosed in Patent Document 1 can be cited.

1: knee bolster 3: knee 5: initial striking part 7: thin wall 9: blow molded body 19: thick part

Claims (5)

A knee bolster composed of a blow-molded body that is deformed by an input of a load from the occupant's knee and absorbs an impact on the knee,
The blow molded body is formed such that a parting line is provided on a load input surface to which the load is input, and a thick part is provided along the parting line,
The load input surface is provided with an initial striking portion to which the load is first applied,
A thin wall is provided adjacent to the initial striking portion,
The thin wall is a knee bolster that is thinner than a total thickness obtained by adding up the thicknesses of both side surfaces of the blow molded body at the initial striking portion. The knee bolster according to claim 1, wherein the thin wall is provided substantially parallel to an input direction of the load. The knee bolster according to claim 1, wherein the initial hitting portion is a flat surface. The knee bolster according to any one of claims 1 to 3, wherein a region around the initial striking portion is inclined with respect to the initial striking portion. The blow molded article has lateral groove ribs on the right side surface and the left side surface,
The lateral groove rib is formed so that the side wall thereof is substantially parallel to the input direction of the load,
The knee bolster according to any one of claims 1 to 4, wherein at least one of the lateral groove ribs does not reach the load input surface.