JP4137252B2 - Boss structure for mounting resin molded products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a mounting boss for a resin molded product.
[0002]
[Prior art]
Conventionally, as one of the mounting methods for a resin molded product in which a foam is provided between the resin base material and the skin, or a resin molded product made up of a single resin base material not covered with the skin or foam, the resin There is a method of performing through a boss integrally formed on the back side of the molded product.
[0003]
For example, in the door trim portion of the automobile shown in FIG. 12 , the armrest 205 made of a resin molded product is fixed by inserting a locking boss 605 formed on the back side of the armrest 205 into the locking hole 815 of the door trim 805. . In the illustrated example, a pocket door trim 705 is fixed to a predetermined portion of the door trim 805 by screws, welding, or the like, and the armrest 205 is attached so as to partially cover the pocket door trim 705. Reference numeral 505 denotes a skin of the armrest 205, 405 denotes a foam, and 305 denotes a base material.
[0004]
Further, when the armrest 205 is attached to the door trim 805 only by the locking boss 605, it is difficult to securely fix the armrest 205, and a gap or a step is generated at the joint S between the armrest 205 and the pocket door trim 705. It was easy. Therefore, recently, in the vicinity of the joint portion on the back surface of the base material 305 of the armrest 205, a cylinder is used instead of the locking boss 605 or in place of the locking boss 605 depending on the shape or the like of the resin molded product. On the other hand, a tapping screw insertion hole 715 is formed in the pocket door trim 705, and the tapping screw T is attached to the mounting boss 105 from the back side of the pocket door trim via the tapping screw insertion hole 715. It was inserted into the hole N and tightened.
[0005]
However, in the fixing method using the tapping screw T, the hole of the mounting boss 105 as shown in FIG. 13 is caused by shrinkage deformation after molding of the armrest 205 and the pocket door trim 705 or variation when the pocket door trim is assembled . N and the position of the tapping screw insertion hole 715 are often misaligned. In this case, it is difficult to insert the tapping screw, and not only is the installation work of the armrest troublesome, but in the worst case, it cannot be installed. there were.
[0006]
In general, the base material of a resin molded product is often molded by injection molding in which a molten resin is injected into a mold to form a molded product having a mold surface shape, and then the molded product is obtained by demolding. . At that time, in the base material having the cylindrical mounting boss, a pin for forming the hole of the mounting boss is erected on the mold surface of the molding die, and the hole of the mounting boss is formed by the pin. Must. The pin needs to be provided in parallel with the die-cutting direction so as not to prevent the die-cutting of the molded product when the molded product is removed.
[0007]
However, since the mold surface of the mold is a three-dimensional shape according to the surface shape of the molded product, the mold drawing direction is less flexible, and the mounting boss direction (tapping screw direction) is also resin molded. There are few degrees of freedom because it depends on the shape of the product (base material of the armrest) and the shape of the counterpart (pocket door trim). For that reason, the die cutting direction and the direction of the mounting boss (direction of the tapping screw) may be different. In that case, in order to prevent the pins on the mold surface from interfering with each other and preventing the molded product from being removed from the mold, the following has been conventionally performed. In other words, the pin is provided in the mold so that it can be moved forward and backward from the mold surface by the cylinder device, and when the base material is molded, the pin is protruded from the mold surface to form a cylindrical mounting boss, and when the molded product is demolded By removing the pin from the mounting boss by retracting the pin to the mold surface position or from the mold surface, the molded product can be removed. As a result, the mold size of the base material mold must be increased, and the size of the molding machine is increased accordingly.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and even if there is some deformation or variation in the resin molded product, it can be securely attached to the mating object with a tapping screw, and it can be removed when the resin molded product is molded. It is an object of the present invention to provide a structure of a boss for mounting a resin molded product that can be easily molded and can prevent an increase in size and cost of the molding die.
[0009]
[Means for Solving the Problems]
That is, according to the present invention, in the resin molded product in which the mounting boss is integrally formed on the resin molded product and the tapping screw is screwed onto the mounting boss, the mounting boss has at least two. A threaded portion formed by two opposing standing walls and a connecting standing wall that connects one end of the opposing standing walls, the side facing the connecting standing wall being open, and screwing the standing wall inner surface with a tapping screw The present invention relates to a structure of a mounting boss for a resin molded product characterized in that it is a surface.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
1 is a cross-sectional view showing the vicinity of a mounting boss of a resin molded product according to a first reference example , FIG. 2 is a perspective view of the mounting boss in FIG. 1, and FIG. 3 is a cross-sectional view along line BB in FIG. 4 is a cross-sectional view showing the vicinity of the mounting boss according to the first embodiment , FIG. 5 is a perspective view of the mounting boss in FIG. 4 as viewed from C, FIG. 6 is a perspective view of the mounting boss according to the second embodiment , and FIG. Is a sectional view of the mounting boss according to the third embodiment , FIG. 8 is a perspective view of the mounting boss according to the fourth embodiment , FIG. 9 is a perspective view of the mounting boss according to the fifth embodiment , and FIG. perspective of the mounting bosses diagram according to example 6, FIG. 11 is a sectional view when mounting the mounting boss of the sixth embodiment. In addition, it shows that the thing with the same code | symbol is the same thing.
[0011]
The resin molded product 20 shown in FIGS. 1 to 3 is attached to the pocket door trim 70 and the door trim 80 as an armrest of an automobile. Of course, the present invention is not limited to automobile parts.
[0012]
In the resin molded product 20, a locking boss 60 and a mounting boss 10 are integrally formed on the back side, which is the mounting side, and is locked to the door trim 80 by the locking boss 60. It is fixed to the pocket door trim 70. The door trim 80 and the pocket door trim 70 are integrally assembled by screws or welding.
[0013]
A locking hole 81 for inserting and locking the locking boss 60 is formed in the door trim 80 at a predetermined position and a predetermined shape. The pocket door trim 70 is formed with a tapping screw insertion hole 71 for inserting and locking the tapping screw T in a predetermined position and a predetermined shape.
[0014]
The resin molded product 20 is formed by laminating a base material 30, a foam 40 and a skin 50, and is molded by a known foam molding (commonly known as mold molding) using a molding die. The base material 30 is formed into a predetermined shape by injection molding or the like, and is made of a hard resin or the like, and a locking boss 60 and a mounting boss 10 are projected on the back surface 31 integrally with the base material 30.
[0015]
The locking boss 60 is located in the vicinity of the center of the base material 30 and the tip 61 has a hook shape. When the tip 61 is inserted into the locking hole 81 of the door trim 80, it is easily locked. It is designed not to come out. The locking boss 60 is useful as a temporary fixing at the time of fixing with the tapping screw T described later, but may not exist depending on the shape or the like of the resin molded product. Further, the locking boss and the locking hole are not limited to those described above, but may be configured to be locked by screws, tapping screws, welding, or the like.
[0016]
The mounting boss 10 has at least two opposing standing walls 11, 11, and in the first reference example , the mounting boss 10 is composed of parallel plate-like ribs facing each other. The inner surfaces 12 and 12 of the standing walls 11 and 11 are screw-forming surfaces that are screwed with the tapping screw T, and the tapping screw T is inserted when the tapping screw T is inserted between the standing walls 11 and 11 while being rotated. The interval W between the two standing walls 11, 11 facing each other so that the threaded portions can be engraved on the standing walls 11, 11, 12, 12 is set slightly smaller than the diameter on the base side of the threaded portion of the tapping screw T. ing. The front end surfaces 13 and 13 of the standing walls 11 and 11 are formed in an angle and shape along the surface of the pocket door trim 70 near the tapping screw insertion hole 71 so as to be able to contact the surface of the pocket door trim 70 without a gap. Yes. Further, the length L of the standing walls 11 is set to be larger than the diameter of the base side of the threaded portion of the tapping screw T.
[0017]
The resin molded product 20 is fixed to the mounting boss 10 by inserting the tapping screw T from the back side of the pocket door trim 70 through the tapping screw insertion hole 71 and rotating between the standing walls 11 and 11 of the mounting boss 10. Made by doing. At that time, since the tapping screw T may be inserted between the two opposing standing walls 11, 11, the hole of the mounting boss and the tapping screw insertion hole of the pocket door trim as in the conventional cylindrical mounting boss. Strict alignment is not required, and the tapping screw T is inserted between the standing walls 11 and 11 and screwed even if the tapping screw insertion hole 71 is slightly shifted in the length L direction of the standing walls 11 and 11. Can do.
[0018]
Further, the mounting boss 10 is composed of two opposing parallel standing walls 11, 11, and is not a cylindrical shape having a tapping screw hole at the center like the conventional cylindrical mounting boss. The mold drawing direction at the time of demolding at the time of molding can be rotated and inclined at a required angle in a direction parallel to the length L direction of the standing walls 11 and 11, and the degree of freedom in the drawing direction is increased. . Therefore, it becomes easy to design a base material mold, and it is not necessary to provide a pin and a cylinder device for forming a tapping screw hole in a mounting boss, which has been conventionally required. In other words, the structure is simple and inexpensive.
[0019]
Will now be described with reference to FIGS. 4 and 5 with the first embodiment of the present invention. In the first embodiment , the resin molded product base 30A molded by injection molding has a mounting boss 10A on the back surface 31A having a substantially U-shape in plan view, and two parallel standing walls 11A and 11A facing each other. The opposing standing walls 11A and 11A are connected to one end of the standing walls 11A and 11A. All the inner surfaces 12A, 12A, 120A of the three standing walls 11A, 11A, 110A, or the inner surfaces 12A, 12A of the two opposing standing walls 11A, 11A constitute a screw portion forming surface that is screwed with the tapping screw T. .
[0020]
The two standing walls 11A, 11A facing each other have a length L larger than the diameter on the base side of the screw portion of the tapping screw T, and the interval W between the standing walls 11A, 11A is the base portion of the screw portion of the tapping screw T. A space where the tapping screw T can be inserted while being tapped into the inner surfaces 12A, 12A, 120A of the three standing walls or the inner surfaces 12A, 12A of the two standing walls by being slightly smaller than the side diameter. It is secured. In particular, when the tapping screw T is inserted while being threaded into the three standing wall inner surfaces 12A, 12A, 120A, the tapping screw T is screwed on one more surface than in the first reference example, so that it is stronger. The resin molded product 20A can be fixed to the pocket door trim 70A. Other configurations are the same as those of the first reference example .
[0021]
Also in this first embodiment , when the resin molded product 20A is mounted, if the tapping screw insertion hole 71A of the pocket door trim 70A is located somewhere between the opposing standing walls 11A, 11A of the mounting boss 10A, tapping is performed. Since the screw T can be screwed between the standing walls 11A and 11A, it is easy to absorb the deviation of the tapping screw insertion hole 71A due to shrinkage of the resin molded product or variations during assembly. Further, vertical wall 11A also stamped direction of the base 30A to the opposite, since the 11A to the length L direction can be requirements rotational inclination increases the degree of freedom, as in the first reference example, the type design It is easy to prevent an increase in size and cost of the mold.
[0022]
FIG. 6 shows a mounting boss 10B according to the second embodiment . This second embodiment is different from the second embodiment in that reinforcing ribs 15B are provided on the outer surfaces 14B, 14B of the opposing standing walls 11B, 11B in the mounting boss 10B, and the other points are different from the second embodiment. The same. The reinforcing ribs 15B support the opposing standing walls 11B, 11B from the outer surface side, and the tapping screw can more reliably bite into the standing wall inner surfaces 12B, 12B (screw forming surface). Further, it can be firmly fixed to the pocket door trim. Although only one reinforcing rib 15B is illustrated, a plurality of reinforcing ribs 15B may be provided on the standing wall outer surfaces 14B and 14B.
[0023]
FIG. 7 shows a mounting boss 10C according to the third embodiment . The third embodiment is different from the second embodiment in that a guide rib 16C of the tapping screw T is erected between the opposing standing walls 11C, 11C of the mounting boss 10C, and the other points are the second embodiment. Same as example. The guide rib 16C is formed perpendicular to the back surface 31C of the base material 30C and lower than the height H of the standing walls 11C and 11C, and when a required amount of the tapping screw T is inserted between the standing walls 11C and 11C. The tip of the tapping screw T comes into contact with the surface 17C of the guide rib 16C facing the connecting standing wall 110C as described above, and the tip of the tapping screw T is inserted into the surface 17C of the guide rib 16C by further insertion of the tapping screw T. To guide along. Further, it is preferable that the tapping screw T is brought into a position where the tapping screw T comes into contact with the inner surface 120C of the connecting standing wall 110C by the guidance. The guide rib 16C guides the tapping screw T when the axial direction D of the tapping screw T is difficult to be determined by the material and shape of the mounting boss 10C or the shape of the pocket door trim 70C near the tapping screw insertion hole 71C. The axial direction D of the tapping screw T can be stabilized.
[0024]
FIG. 8 shows a mounting boss 10D according to the fourth embodiment . In this embodiment, the inner surface 120A of the connecting standing wall 110A in the mounting boss of the second embodiment has an arc shape R. As a result, when the tapping screw comes into contact with and engages with the inner surface 120D of the connecting standing wall 110D, the contact screwing portion increases, and the tapping screw is more firmly fixed to the mounting boss 10D.
[0025]
FIG. 9 shows a mounting boss 10E according to the fifth embodiment . In the fifth embodiment , a thick portion 18E is provided on the outer periphery of the standing wall from the connecting standing wall 110E side to the outer periphery of the connecting standing wall 110E of the two opposing standing walls 11E and 11E in the mounting boss 10E. By providing this thick portion 18E, sink F is generated at the boundary between the thick portion 18E and the general thick portion 19E of the standing walls 11E and 11E after injection molding of the base material 30E. The guide action of the tapping screw can also be exhibited. The direction of the boundary line K between the thick portion 18E and the general thick portion 19E is set to the axial direction of the tapping screw.
[0026]
FIGS. 10 and 11 show a mounting boss 10G according to the sixth embodiment . In the sixth embodiment , the guide rib in the mounting boss of the third embodiment is composed of a tapping screw locking portion 161G and a tapping screw guiding portion 162G. The guide rib 16G is provided between the opposing standing walls 11G and 11G in the mounting boss 10G as in the third embodiment, and is formed lower than the height H of the standing walls 11G and 11G. Yes.
[0027]
The tapping screw locking portion 161G of the guide rib 16G is formed so as to be substantially parallel to the axial direction D of the tapping screw T from the back surface 31G of the base material 30G. Further, the tapping screw guiding portion 162G is formed to be perpendicular to the back surface 31G of the base material 30G from the tip of the tapping screw locking portion 161G. When a required amount of the tapping screw T is inserted between the standing walls 11G and 11G, the tapping screw T is placed on the surface 172G of the tapping screw guiding portion 162G of the guide rib 16G facing the connecting standing wall 110G as described above. The leading end abuts, and the further tapping screw T is inserted to guide the leading end of the tapping screw T along the surface 172G of the tapping screw guiding portion 162G. Further, it is preferable to form the guide rib 16G so that the tapping screw T is brought into contact with and screwed with both the inner surface 120G of the connecting standing wall 110G and the surface 171G of the tapping screw locking portion 161G by the guidance.
[0028]
The guide rib 16G is formed by the tapping screw guiding portion 162G when the axial direction D of the tapping screw T is difficult to determine due to the material and shape of the mounting boss 10G or the shape near the tapping screw insertion hole 71G of the pocket door trim 70G. The tapping screw T can be guided to stabilize the axial direction D of the tapping screw T. When the inner surface 120G of the connecting standing wall 110G and the surface 171G of the tapping screw engaging portion 161G together with the inner surfaces 12G and 12G of the standing walls 11G and 11G are screw portion forming surfaces that are screwed with the tapping screw T, The tapping screw T is screwed on one surface, and the resin molded product can be more firmly fixed to the pocket door trim.
[0029]
For convenience, the mounting boss of the armrest of the automobile has been described as an example. However, the present invention is not limited to the above-described application, and can be used for mounting bosses of various resin molded products. Also, the size, shape and the like are not limited to those given in the examples.
[0030]
【The invention's effect】
As illustrated and described above, according to the structure of the mounting boss for a resin molded product according to the present invention, the mounting boss has at least two opposed standing walls, and the space between the standing walls is screwed with the tapping screw. Because it is a threaded surface, even if there is some deformation after molding or variation during assembly of the resin molded product, it is easy to align the mating tapping screw insertion hole and mounting boss, Screwing with a tapping screw can be performed reliably. Further, according to the present invention, the structure of the molding die is simplified and the die size can be reduced, so that the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the vicinity of a mounting boss of a resin molded product according to a first reference example of the present invention.
FIG. 2 is a perspective view of the mounting boss of FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is a sectional view showing the vicinity of a mounting boss according to the first embodiment .
5 is a perspective view of the mounting boss of FIG.
FIG. 6 is a perspective view of a mounting boss according to a second embodiment .
FIG. 7 is a cross-sectional view of a mounting boss according to a third embodiment .
FIG. 8 is a perspective view of a mounting boss according to a fourth embodiment .
FIG. 9 is a perspective view of a mounting boss according to a fifth embodiment .
FIG. 10 is a perspective view of a mounting boss according to a sixth embodiment.
FIG. 11 is a cross-sectional view of the mounting boss of the sixth embodiment when mounted.
FIG. 12 is a cross-sectional view showing the vicinity of a conventional mounting boss.
FIG. 13 is a cross-sectional view showing a shift in a conventional mounting boss.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Mounting boss 11 Standing wall 20 Resin molding 30 Base material 60 Locking boss 70 Pocket door trim 80 Door trim T Tapping screw

Claims (2)

In a resin molded product in which a mounting boss is integrally formed on a resin molded product and is fixed to a counterpart by screwing a tapping screw into the mounting boss, the mounting boss has at least two opposing standing walls ; It is composed of a connecting standing wall that connects one end of the opposing standing wall, the side facing the connecting standing wall is opened, and the inner surface of the standing wall is a screw part forming surface that is screwed with a tapping screw. The structure of the boss for mounting resin molded products.   2. The structure of a mounting boss for a resin molded product according to claim 1, wherein the mounting boss is substantially U-shaped in plan view.

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