JP5863271B2 - Inserted threaded insert and insert molding method - Google Patents

Description

  The present invention is an insert-molded threaded insert having a shank provided with flanges defining two heads on both axial sides of the insert at an axial end portion, and the thread portion is formed in the shank. A screw provided with an inner thread axial section to prevent the rotation of the insert after insert molding and means for preventing the axial movement of the insert after insert molding are arranged on the outside of the shank. With insert.

  The present invention is also a method of insert molding a threaded insert to be insert molded, comprising a shank provided with flanges defining two heads on both axial sides of the insert at the axial end, The shank is provided with an inner thread axial section for forming a threaded portion, one outer surface of the shank is provided with means for preventing the insert from rotating after insert molding, and on the other hand, the insert shaft after insert molding The present invention relates to a method provided with means for preventing directional movement.

  There are several types of threaded fixtures that are inserted into insert molded parts, such as fixtures that are inserted after the part is molded, or fixtures that are inserted before molding. The invention relates to the latter type in the field of insert molding threaded inserts.

  Conventionally, such a threaded insert has a threaded portion provided over its entire height, and there can be a knurled cut formed on the outer surface of the shank as a means to prevent the insert from rotating after insert molding. So that it is formed by a lathe. In addition, a rectangular cross-section groove may be formed at the joint between each head and the outer surface of the remaining portion of the shank.

  In one insert molding technique, the insert described above is pressed through one of its heads against the first part of the mold for insert molding, after which the second part of the mold is blocked by the mold. Press until The height between the two parts of the mold after closing is constant in one mold, but can vary from one mold to another. Similarly, the axial length between the insert heads is usually within predetermined tolerance limits, but may vary from manufacturing to manufacturing.

  It causes a change in two parameters that is too short or too long in the axial direction compared to the height between the two parts of the mold after the insert is closed. In the former case, the quality of the insert molding is reduced due to the accidental engagement of the material between one of the insert heads and the corresponding mold part. In the latter case, the mold blockage is accompanied by irreversible damage to the insert screw part, and the quality of the insert molded part is deteriorated.

  An insert-molded insert provided with two heads and a threaded inner hole is described in JP-A-8-156013. The insert is provided on its outer surface and has a groove concentric with the thread.

  It is an object of the present invention to provide an insert that mitigates both the risk of accidental engagement of material between one of the insert heads and the corresponding mold part and the risk of damage to the insert thread. It is said.

  The insert according to the invention has at least one fuse region in which the shank is arranged between the thread axial area and one of the heads and is largely axially deformed, the fuse area being in the thread axial direction. It is excellent in that it is configured to be deformed by a predetermined axial compression force applied to the head without causing deformation in the area.

  Such a fuse region shortens the axial length of the insert by the effect of a predetermined axial load without causing deformation and damage to the threaded portion when, for example, a mold for insert molding is closed. It has the effect that it becomes possible.

Further, the insert molding method according to the present invention includes:
-Pressing one of the insert heads against the first part of the insert mold;
-Pressing the second part of the mold against the other head of the insert;
The two parts of the mold are brought into close proximity by applying an axial compressive force to the head of the insert, and the screw thread is not deformed until the mold is completely closed, Deforming at least one fuse region which is disposed between the mountain axial area and one of the heads and which is largely deformed in the axial direction;
A step of injecting an insert molding material into a mold around the insert.

  Another advantage and feature is a detailed embodiment of the invention given for the purpose of illustrating a non-limiting example, the example of a threaded insert according to the invention shown in a longitudinal half section The following description of a detailed embodiment of the invention shown in the single accompanying drawing will become apparent.

FIG. 1 is a view showing an example of a threaded insert to be insert-molded according to the present invention.

  The single accompanying drawing shows an example of an insert molded threaded insert 10 according to the present invention. The right part shows the insert as seen from the outside and the left part shows the cross section in the axial direction.

  The insert 10 includes a tubular shank 11 that faces a direction along a rotation axis that is embodied in the axial direction X of the insert. The shank 11 is provided with a laterally outward flange at its axial end, thereby defining the heads 12, 13 on both axial sides of the insert. The axial length of the insert is indicated by L.

  Between the heads 12, 13, the shank 11 is provided with an inner thread axial section T1 for forming a thread 14 over at least part of the axial length L of the insert. Such a threaded portion 14 is configured to cooperate with a screw or bolt type fastening means (not shown) after insert molding.

  The shank 11 has means for preventing rotation of the insert after insert molding and means for preventing axial movement of the insert after insert molding. These two types of means are arranged outside the shank, complemented by their mechanical function. The anti-rotation means is achieved, for example, by being a cylinder including a directing curve in which the outer surface of the shank 11 exhibits a polygon over at least a part of its axial length L. In essence, a cylinder is a surface of space defined by a line called a generating line that passes through various points representing a closed flat curved surface, the so-called orientation curved surface, and maintains a certain direction. is there.

  An annular groove (15) is formed in the joint between one of the heads 12, 13 of the insert 10 and the outer surface of the remaining part of the shank 11. The annular groove (15) is formed on the outer surface of the shank and in a plane perpendicular to the axis X thereof. As an example, the cross section of the groove has a circular bottom and is generally V-shaped. In this case, one of the side walls of the groove can be orthogonal to the complete lateral direction, ie, the direction X, but the other side wall of the groove 15 is inclined in the direction of the other head. The main function of such a groove is to form a means to prevent axial movement of the insert after insert molding.

  In the illustrated example, the outer surface of the shank that separates the heads 12 and 13 is a cylinder that includes an orientation curved surface that exhibits a polygonal shape, for example, a hexagonal shape, in a region other than the region where the groove 15 is formed over the entire height. .

  Without being limited, the insert 10 is a penetrating structure, i.e. the internal duct is open at the location of two openings 16, 17 which are the ends through the two heads 12, 13. The portion of the duct that couples the threaded portion 14 to the opening 16 that opens in the head 12 can be formed by a cone 18 that is inclined in the direction of the corresponding head 12.

  A hole 19 is disposed in the axial section T2 of the shank 11 different from the thread axial section (T1). The hole 19 connects the head 13 to the head 12 on the opposite side where the groove 15 is disposed. Are connected. The hole 19 has an inner diameter larger than the diameter of the screw portion 14. This hole 19 has the effect of reducing the thickness of the shank 11 along the axial section T2 with respect to the thickness along the thread axial section T1.

  According to the present invention, the shank 11 has at least one fuse region that is largely axially deformed and disposed between the thread axial section T1 and one of the heads 12,13. The fuse region is configured to be deformed by a predetermined axial compressive force applied to the heads 12 and 13 without causing deformation of the thread axial region T1, and consequently the threaded portion 14.

  The first fuse region is formed by the arrangement of the holes 19. The second fuse region can be formed by the annular groove 15. The action of the annular groove 15 is enhanced on the inside by the provision of the cone 18.

  At the tip of the thread axial section T1 (end facing in the direction along the axis of the section T1), the thread preferably continues directly to the thread axial section T1, as in the example of FIG. It can be interrupted to allow the formation of at least one fuse region. In other words, the fuse region has no threads inside the shank. This always makes it possible to screw the corresponding element into the insert after deformation of the fuse region. Unlike the thread, the insert can easily screw the element having a thread corresponding to the threaded portion of the thread axial section T1, as described above, even after the fuse region is deformed. Can have holes 19 that allow Such holes prevent, for example, the formation of pads within the shank that prevent element passage and screw fastening.

  As an advantage of the manufacturing technique, the insert 10 can be made by cold heading. In addition, the present invention can be applied without problem to an insert having a blind structure. In this case, the internal duct defined by the shank will only open one of the heads at the position of the single opening.

  One technique for insert molding the threaded insert 10 is to press against the first part of the insert molding die through one of the heads 12, 13 as described above, and then the second of the mold. This part is pressed until the mold is closed. The advantage of the technology is that the axial length L of the insert 10 and the two parts of the mold are such that the height of the two parts of the mold after closure is slightly smaller than the expected axial length L. It is to provide that the difference in height between the two is smaller than the axial deformation capability of the fuse region provided in the insert.

  Thus, when the second mold part is fitted, the latter contacts the head 13 of the insert without reaching the closed position of the mold as the first stage. A mechanical force is then applied to the second mold part and movement is continued until closure is achieved. This is caused by the axial compressive force applied to the heads 12, 13 being transmitted to the insert at a value greater than a predetermined axial compressive force that deforms the fuse region of the insert. Finally, insert molding material can be injected into the insert mold.

In other words, the method of insert molding the threaded insert 10 to be insert-molded as described above is as follows.
Pressing one of the heads 12, 13 of the insert 10 against the first part of the insert mold,
Pressing the second part of the mold against the other head 13 of the insert 10;
By applying an axial compressive force to the heads 12, 13 of the insert 10, the two parts of the mold are brought into close proximity without causing deformation in the thread axial section T1 until mold closure is achieved. Deforming at least one fuse region which is arranged between the screw thread axial section T1 and one of the heads 12, 13 and which is largely deformed in the axial direction;
And a step of injecting an insert molding material into a mold around the insert.

Claims (7)

In threaded inserts that are insert molded,
A shank (11) provided with flanges defining two heads (12, 13) on both axial sides of the insert (10) at the axial end,
The shank (11) is provided with an inner thread axial area (T1) for forming a thread (14),
A means for preventing rotation of the insert (10) after insert molding and a means for preventing axial movement of the insert (10) after insert molding are disposed outside the shank (11).
The shank (11) has at least one fuse region that is largely axially deformed and disposed between the thread axial region (T1) and one of the heads (12, 13).
The screw region is configured such that the fuse region is configured to be deformed by a predetermined axial compressive force applied to the head without causing deformation of the thread axial region (T1). insert.   The fuse region is formed by an annular groove (15) provided on an outer surface of the shank (11) and extending in the circumferential direction about the axis (X). Inserts.   The fuse region is formed by a hole (19) disposed in an axial section (T2) of the shank (11) that is different from the thread axial section (T1). 3. Insert according to claim 1 or 2, characterized in that it has an inner diameter larger than the diameter of the threaded portion (14).   The outer surface of the shank (11) is a cylinder including an oriented curved surface showing a polygon over at least a part of the axial length (L). insert. The insert according to any one of claims 1 to 4 , wherein the insert is a penetrating structure. The insert according to any one of claims 1 to 4 , wherein the insert has a blind structure. A shank (11) provided with flanges defining two heads (12, 13) on both axial sides of the insert (10) is provided at an axial end, and the thread (14) is provided on the shank (11). An inner thread axial section (T1) is formed for forming the shank (11), one outer surface of the shank (11) is provided with means for preventing rotation of the insert (10) after insert molding, In a method of insert molding a threaded insert (10) to be insert-molded, provided with means for preventing axial movement of the insert (10) after insert molding,
Pressing one of the heads (12, 13) of the insert (10) against a first part of an insert mold;
Pressing the second part of the mold against the other head (12, 13) of the insert (10);
Thread axial direction until two parts of the mold are brought into close proximity by applying an axial compressive force to the head (12, 13) of the insert (10) until closure of the mold is achieved At least one fuse region deformed in a large axial direction disposed between the thread axial direction region (T1) and one of the heads (12, 13) without causing deformation in the region (T1). A step of deforming;
Injecting insert molding material into the mold around the insert (10).

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