JP2014057990A - Method of producing press-in part and press-in part produced thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the holding power for a press-in part to be forced into a hole of a resin product.SOLUTION: In a method of producing a press-in part 1 having a cylindrical or square cylindrical metal-made press-in part to be forced into a hole of a resin product, grooves extending in parallel with the axial direction x respectively from both ends of the press-in part in the forcing direction of the press-in part are formed by pressing a die onto the press-in part to move relatively, and the confluent part of the grooves is raised in the radial direction of the press-in part to form a protrusion 5. Since the protrusion can thereby be raised higher by plastic deformation in forming the grooves, the holding power for the press-in part on forcing into the hole of the resin product can be enhanced.

Description

  The present invention relates to a press-fit component that is press-fitted into a hole of a resin product, and more particularly, to a method for manufacturing the press-fit component.

  Generally, when a screw member such as a bolt is screwed into a hole formed in a resin part (hereinafter referred to as a resin product), depending on the strength and toughness of the resin product, May rotate around and loosen. Therefore, a structure in which a hollow cylindrical press-fitting part (for example, a collar) formed of a material harder than resin, such as metal, is press-fitted into a hole of a resin product, and a screw member is screwed into the press-fitted part is widely used. ing.

  Patent Document 1 discloses a structure of a nut (a nut whose cross section perpendicular to the axial direction is a regular polygon) pushed into a hole of a resin product. In the nut, a plurality of ridge line portions (corner portions) extending in parallel with the axial direction are provided with protruding portions that protrude in the radial direction. According to this, when the nut is pushed into the hole of the resin product, the protruding portion bites into the inner wall of the hole and restricts the rotation around the axis of the nut, so that the holding force of the nut can be increased.

JP 2007-315538 A

  By the way, the following manufacturing method is employ | adopted for the nut of patent document 1 in order to provide a protrusion part. That is, using a forging die, a part of the die is pressed against one end in the axial direction of the nut, and the die is relatively moved halfway along each ridge line portion of the nut. Accordingly, each ridge line portion is chamfered by passing a die, and a protruding portion that rises in the radial direction by plastic deformation is formed at the tip of the chamfer.

  However, when the manufacturing method of Patent Document 1 is applied to a nut having a relatively short overall axial length (total thickness), the height of the ridge line portion that rises in the radial direction, that is, the height of the protruding portion is reduced. There is a risk that the holding force of the nut with respect to the hole of the hole will be reduced.

  An object of the present invention is to increase the holding force of a press-fitted part press-fitted into a hole of a resin product.

  In order to solve the above problems, the present invention relates to a method for manufacturing a press-fitted part having a press-fitting part made of a cylindrical or rectangular tube that is press-fitted into a hole of a resin product. Thus, a groove extending in parallel with the axial direction is formed from both ends of the press-fitting portion in the press-fitting direction, and a converging portion of the groove is raised in the radial direction of the press-fitting portion to form a protruding portion.

  According to such a manufacturing method, since the portions plastically deformed at the time of forming the groove can be gathered from the both ends in the press-fitting direction to the protrusions, the protrusions in the radial direction of the protrusions can be increased. Thereby, since a protrusion part can be raised more effectively, the retention strength of the press-fit component press-fitted in the hole of the resin product can be increased.

  Further, the press-fitted component manufactured in this way has a cylindrical or rectangular tube-shaped metal press-fitted portion that is press-fitted into the hole of the resin product, and the press-fitted portion has a plurality of protrusions protruding from the outer surface. It has a protrusion part, and the groove | channel which extends in parallel with an axial direction from the front end of a press-fit part to the rear end is formed in the front-back direction of each protrusion part, It is characterized by the above-mentioned.

  In this case, it is preferable that the plurality of projecting portions are provided at a central portion in the axial direction of the press-fit portion.

  According to this, since the lengths of the grooves on both sides of the protruding portion are equal, variation in the shape of the protruding portion (particularly the shape of the protruding portion before and after in the press-fitting direction) can be suppressed, and the holding force of the press-fitting parts can be reduced. It can be stabilized.

  ADVANTAGE OF THE INVENTION According to this invention, the retention strength of the press-fit component press-fitted in the hole of a resin product can be improved.

It is a perspective view which shows the external appearance of the press-fit component to which this invention is applied. It is a perspective view which shows the external appearance of the press-fit component manufactured by the conventional manufacturing method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a method for manufacturing a press-fitted part to which the present invention is applied and an embodiment of a press-fitted part manufactured by the manufacturing method will be described with reference to the drawings. The press-fitting component of the present embodiment is used by being press-fitted into a hole (regardless of whether it is penetrating) of a resin product. In the present embodiment, a metal collar formed in a cylindrical shape will be described as an example of the press-fitting part. However, the press-fitting part is not limited to the collar, and may be a metal product such as a square tube nut. .

  FIG. 1 is a perspective view showing an appearance when the collar of the present embodiment is viewed obliquely with respect to the axial direction X. FIG. As shown in FIG. 1, the collar 1 includes a cylindrical portion 3 that is a press-fitted portion that is press-fitted into a hole of a resin product, a plurality of protruding portions 5 that are formed on the outer peripheral surface of the cylindrical portion 3, and an outer periphery of the cylindrical portion 3. It has a groove 7 formed along the surface. The cylindrical portion 3 has a through hole 9 formed in the center, and has the same outer diameter from one end to the other end in the axial direction X. In the collar 1, the axial direction X is the press-fitting direction.

  At both ends in the axial direction of the cylindrical portion 3, chamfers 15 are applied to the boundary portions with the inner peripheral surface 11 and the outer peripheral surface 13, respectively. By providing the chamfer 15 in this manner, for example, work when the collar 1 is press-fitted into the hole or when a female screw is formed in the through hole 9 is facilitated.

  The protruding portion 5 is formed by raising a part of the outer peripheral surface 13 of the cylindrical portion 3 in the radial direction when the groove 7 is formed by a manufacturing method described later. Four protrusions 5 are provided at equal intervals in the circumferential direction of the outer peripheral surface 13, all on the same plane orthogonal to the axial direction X, and the central portion of the entire length (thickness) of the cylindrical portion 3 in the axial direction X. Placed in. The diameters of the circles in contact with the four protruding portions 5 are larger than the diameter of the cylindrical portion 3. The protrusions 5 are each formed with a triangular plane 17 before and after the axial direction X.

  Grooves 7 extending in parallel with the axial direction X so as to sandwich the protruding portion 5 are formed on the front and rear of each protruding portion 5 in the press-fitting direction from the front end 19 to the rear end 21 of the cylindrical portion 3, respectively. . The groove 7 has a U-shaped cross section when viewed from the axial direction, and the dimension in the width direction perpendicular to the extending direction of the groove 7 is substantially the same as the dimension in the width direction of the protrusion 5.

  Next, the manufacturing method of the collar 1 of this embodiment is demonstrated. However, since the cylindrical part 3 can use a general-purpose product (purchased product), in this embodiment, it demonstrates focusing on the method of forming the protrusion part 5 in the cylindrical part 3. FIG. In the following description, the description will be given focusing on one projecting portion 5 for ease of explanation.

  First, the cylindrical part 3 in which the protrusion part 5 and the groove | channel 7 are not formed is prepared, and this is set to the metal mold | die for forging in which the die | dye was integrated. Then, a die is pressed against the front end 19 of the cylindrical portion 3, and the die is relatively moved along the outer peripheral surface 13 of the cylindrical portion 3 in parallel with the axial direction X. At this time, the cylindrical part 3 may be fixed and the die may be moved, or the die may be fixed and the cylindrical part 3 may be moved. The distance that the dies move relative to each other is approximately half the total length of the cylindrical portion 3. A groove 7a is formed on the outer peripheral surface 13 of the cylindrical portion 3 by plastic deformation, and a portion that rises in the radial direction of the cylindrical portion 3 by plastic deformation is formed at the tip of the groove 7a (in the middle of the entire length of the cylindrical portion 3). The

  Next, the cylindrical part 3 in which the groove 7a is formed in this way is inverted before and after the axial direction X and set again in the same mold. Then, a die is pressed against the rear end 21 of the cylindrical portion 3, and the die is moved relative to the extension line of the groove 7 a along the outer surface of the cylindrical portion 3. At this time, the distance that the dies move relatively is about half of the entire length of the cylindrical portion 3. According to this, the portion formed so as to be raised at the tip of the groove 7a and the portion formed so as to be raised at the tip of the groove 7b join together, and the portion formed at the tip of the groove 7a before forming the groove 7b. In addition, the protruding portion 5 that is raised in the radial direction of the cylindrical portion 3 is formed.

  Here, as a comparative example, FIG. 2 shows a color manufactured by the manufacturing method of Patent Document 1. In FIG. 2, the same configuration as that of the present embodiment is represented by the same reference numeral.

  The collar 23 shown in FIG. 2 has the groove 7a on the front end 19 side of the protrusion 25, but no groove is formed on the rear end 21 side of the protrusion 25.

  When comparing the collar 1 of the present embodiment with the collar 23 of the comparative example, the protruding portion 5 (FIG. 1) of the collar 1 is higher in the radial direction of the cylindrical portion 3 than the protruding portion 25 (FIG. 2) of the collar 23. Is getting higher. That is, in the present embodiment, when the two grooves 7a and 7b are formed, the protruding portions 5 are formed by gathering the plastically deformed portions at the tips of the grooves 7a and 7b and raising them in the radial direction. However, in the comparative example, since the groove 7b is not provided, the protruding portion 25 cannot be sufficiently raised, and the radial height as in the protruding portion 5 of the present embodiment cannot be ensured.

  The collar 1 formed in this way is, for example, press-fitted into a through hole of a resin product (not shown). The outer diameter of the cylindrical portion 3 is set slightly larger than the diameter of the through hole, for example. When the collar 1 press-fitted into the through-hole advances through the through-hole, the cylindrical portion 3 enters while expanding the through-hole, and the plurality of protruding portions 5 enter while biting into the inner wall of the through-hole. Therefore, the collar 1 can ensure a high holding force by the protrusion 5 firmly biting into the inner wall of the through hole.

  By the way, when the collar 1 is press-fitted into the through hole of the resin product, the protrusion 5 crushes the inner wall of the through hole, and the press-fitting proceeds while scraping off. At this time, a part of the inner wall of the through hole scatters as burrs, while the protruding portion 5 bites into the inner wall of the through hole, thereby causing a phenomenon that the inner wall of the through hole in the press-fitting direction rises.

  In this respect, the collar 1 of the present embodiment is formed with grooves 7 on both sides in the axial direction so as to sandwich the protruding portion 5, so that even if either end of the axial direction is press-fitted in the press-fitting direction, the collar 1 protrudes. The groove 7 can be positioned in the press-fitting direction of the part 5. Therefore, regardless of the press-in direction of the collar 1, the burrs and the bulge of the inner wall can always be accommodated in the groove 7, so that the burrs can be prevented from scattering from the through holes and the peripheral deburring can be prevented. Work can be reduced. In addition, since the operation for confirming the insertion direction of the collar 1 is not required, the efficiency of the operation can be improved.

  As mentioned above, although embodiment of this invention has been explained in full detail with drawing, the said embodiment is only an illustration of this invention and this invention is not limited only to the structure of the said embodiment. Needless to say, changes in design and the like within the scope of the present invention are included in the present invention.

  For example, in the collar according to the present embodiment, the press-fitting part that is press-fitted into the hole of the resin product is the cylindrical part 3, so that the entire collar is press-fitted into the hole, but the press-fitting part is a part that constitutes a press-fitting part. Alternatively, a portion that is not press-fitted into the through hole of the resin product may be formed in the axial direction.

  Moreover, although this embodiment demonstrated the example which forms a protrusion part in a cylindrical press-fit part, when forming a protrusion part in a square tube-like press-fit part, for example, along each ridgeline part (corner part) The groove may be formed, and the confluence portion of the groove may be raised in the radial direction in the same manner as in the present embodiment to form the protruding portion.

DESCRIPTION OF SYMBOLS 1 Color | collar 3 Cylindrical part 5 Protrusion part 7 Groove 9 Through-hole 17 Plane 19 Front end 21 Rear end

Claims (3)

  In the method of manufacturing a press-fitting part having a cylindrical or square-shaped metal press-fitting part that is press-fitted into a hole of a resin product, the press-fitting direction of the press-fitting part is achieved by pressing a die against the press-fitting part and moving the die relative Forming a groove extending in parallel with the axial direction from both ends of the groove, and forming a protruding portion by raising a confluence portion of the groove in a radial direction of the press-fitting portion.   In a press-fitting part having a cylindrical or rectangular tube-shaped metal press-fitted portion that is press-fitted into a hole of a resin product, the press-fitted portion has a plurality of projecting portions that project from the outer surface, and the press-fitting direction of each projecting portion The press-fitting part is characterized in that a groove extending in parallel with the axial direction is formed from the front end to the rear end of the press-fitting portion on the front and rear sides.   The press-fitting component according to claim 2, wherein the plurality of protrusions are provided in a central portion in the axial direction of the press-fitting portion.

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