JP2000052435A - Metal screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a metal screw of superior torque strength when being press-fitted into a resin part. SOLUTION: A metal screw 1 is connected with a resin part press-fitted into a hole of a resin part with the hole on the outer peripheral face by utilizing the ultrasonic vibration, and a plurality of vertical channels 12 are formed in the axial direction, while a plurality of horizontal channels 13 are formed on the outer peripheral face in the direction crossing the axial direction, and ribs 14 are formed in the horizontal channels 13 in the direction crossing the direction in which the horizontal channels 13 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal screw which is press-fitted into a resin part by using ultrasonic vibration.

[0002]

2. Description of the Related Art It has been conventionally practiced to press an iris-shaped knurled metal screw (a metal member for fastening) having a lattice-shaped groove on the outer periphery thereof into a resin molded product by using ultrasonic vibration. I have. When the metal screw is press-fitted into the resin molded product using ultrasonic vibration, frictional heat is generated between the resin molded product and the metal screw, and the resin molded product is melted. The molten resin is filled in the groove of the metal screw, and the metal screw is bonded to the resin molded product. Characteristics required when a metal screw is press-fitted into a resin molded product include strength characteristics such as torque resistance against torsion torque and pull-out resistance against a pulling load. In order to obtain such strength characteristics, for example, Japanese Patent Application Laid-Open No. 2-9620 discloses that a vertical groove receiving a torsional torque is formed on the outer periphery of a metal screw and a horizontal groove receiving a punching load is formed. Have been.

[0003]

For example, when the shape of a resin molded product is complicated like an intake manifold, a portion where the resin is not sufficiently filled occurs at the time of molding the resin molded product, so that the filling density of the resin is low. It becomes a resin molded product having a portion. When a conventional metal screw is press-fitted into a portion of a resin molded product having a low resin filling density, there is a problem that sufficient torque strength cannot be obtained. An object of the present invention is to provide a metal screw capable of obtaining high torque strength.

[0004]

The present invention to achieve the above object is as follows. (1) A metal screw which is press-fitted into a hole of a resin component having a hole by using ultrasonic vibration and is joined to the resin component on an outer peripheral surface, wherein a plurality of longitudinal grooves are formed in the outer peripheral surface in an axial direction. Are formed, a plurality of lateral grooves are formed in the outer peripheral surface in a direction intersecting with the axial direction, and ribs are formed in the lateral grooves in a direction intersecting with the direction in which the lateral grooves are formed. Metal screw. (2) the rib is formed in the lateral groove in the axial direction;
The metal screw according to (1). (3) The peaks between the adjacent vertical grooves are discontinuous in the axial direction by the horizontal grooves, and the inside of the horizontal groove between the adjacent peaks in the axial direction is formed. The metal screw according to (2), wherein the rib is formed on the metal screw. (4) The metal screw according to (1), wherein the rib is formed in a direction crossing the axial direction in the lateral groove. (5) The metal screw according to (1), (2), (3), or (4), wherein a plurality of the ribs are formed at equal pitches in the lateral groove. (6) The metal screw according to (1), (2), (3), (4), or (5), wherein the vertical groove, the horizontal groove, and the rib are formed by press molding.

In the above metal screws (1) to (6), the ribs are formed in the lateral grooves, so that the torque strength can be improved. In the metal screw of (4), since the rib is formed in the transverse groove in the direction intersecting in the axial direction, the torque strength is improved and the pulling strength is improved. In the metal screw of (5), since a plurality of ribs are formed at equal pitches in the lateral groove, stable torque strength is easily obtained. In the metal screw of (6), since the vertical groove, the horizontal groove, and the rib are formed by press molding, the cost is lower than that of the mechanical processing.

[0006]

1 and 2 show a metal screw according to a first embodiment of the present invention. FIG. 3 shows a method of manufacturing a metal screw common to all embodiments of the present invention. 8 shows a push cam which can be used for manufacturing a metal screw common to all embodiments of the present invention, and FIG. 9 shows a rear surface of the push cam used for manufacturing a metal screw of the first embodiment of the present invention. FIG. 10 schematically shows a side view of a metal screw according to a second embodiment of the present invention, and FIG.
FIG. 12 schematically shows a side surface of a metal screw according to a third embodiment of the present invention, FIG. 12 shows a back surface of a push cam used for manufacturing the metal screw according to the third embodiment of the present invention, and FIG. Fig. 7 schematically shows a side view of a metal screw of a fourth embodiment. The parts common to all the embodiments are denoted by the same reference numerals throughout the embodiments. First, an outline of a metal screw common to all embodiments of the present invention will be described with reference to FIGS. The metal screws of all the embodiments of the present invention are attached to a resin component such as a resin intake manifold. Thereby, the metal component can be coupled to the resin component via the metal screw.

[0007] The metal screw 1 has a shaft portion 10 provided with a hole 19 in the center. A plurality of vertical grooves 11 extending in the axial direction and a plurality of horizontal grooves 13 extending in the direction intersecting in the axial direction are formed on the outer peripheral surface of the shaft portion 10. In the lateral groove, one or a plurality of ribs 14 extending in a direction intersecting with the direction in which the lateral groove 13 is formed are formed. The rib 14
It connects to the bottom surface 13a and both side surfaces 13b of the lateral groove. On the inner peripheral surface of the metal screw 1, a female screw 15 for screwing a metal component to the metal screw is formed.

The shaft portion 10 in which the vertical groove 11 and the horizontal groove 13 of the metal screw 1 are formed has an outer diameter gradually reduced from the upper part to the lower part, and has a taper of about 2 °. A flange (head) 16 is provided at the upper end of the shaft.

The vertical grooves 11 are formed at equal pitches in the circumferential direction and all have the same axial length (for example, 10 mm). The shape of the vertical groove 11 is arbitrary, and is, for example, substantially V-shaped in cross section. Crests 12 between adjacent vertical grooves 11 are discontinuous in the axial direction by horizontal grooves. The shape of the peak 12 is arbitrary. FIG. 1 shows a shape in which the top (projecting end) of the ridge 12 on the upper side in the axial direction is sharp, and the top has a plane whose width is wider as the ridge 12 on the lower side. Note that the tops of all the ridges 12 may be sharp, or the tops of all the ridges 12 may be planar. The vertical groove 11 receives a torsional torque, and the groove depth of the vertical groove 11 affects the torque strength. For example, the depth of the vertical groove is 0.4 to 0.9 mm, more preferably 0.5 to 0.9 mm.
When the thickness is 0.8 mm, a high torque strength is obtained.

As shown in FIG. 1, the lateral groove 13 is formed in a circumferential direction of the outer peripheral surface of the metal screw (a direction perpendicular to the axial direction). Alternatively, it may be formed in a direction inclined with respect to the circumferential direction. Each of the lateral grooves 13 has a substantially equal pitch between adjacent lateral grooves, and is formed over the entire outer peripheral surface. The shape of the lateral groove is, for example, substantially U-shaped in cross section. Since the lateral groove receives the punching load, the groove depth of the lateral groove affects the punching load. For example, when the depth of the lateral groove is 0.4 to 0.9 mm, more preferably 0.5 to 0.8 mm, a high punching strength can be obtained.

The rib 14 is formed in the lateral groove 13 and has a predetermined thickness (length in the circumferential direction) and a predetermined height (height radially protruding from the bottom surface of the horizontal groove). The thickness and height vary depending on the position where the ribs 14 are formed. However, when the ribs 14 are formed in the lateral grooves 13 between the tops of the adjacent ridges, for example, the thickness is 0.2 ０．６0.6 mm.

Further, on the rear surface of the flange portion 16, grooves having the same number and the same phase as the vertical grooves may be provided on an extension of the vertical grooves. Thereby, torque is improved. The shape of the groove provided on the back surface of the flange 16 may be any shape, for example, the width of the groove is narrowed toward the outer edge of the flange, and the width of the groove is the same toward the outer edge of the flange. There are a straight shape and a curved shape in which the groove is curved toward the outer peripheral end of the flange. Also,
The depth of the groove may be shallower toward the outer peripheral end of the flange.

The outer peripheral surface of the lower end portion 17 of the shaft portion 10 of the metal screw 1 is located radially inside the vertical groove. A vertical groove and a horizontal groove are not formed in the lower end portion 17. Thereby, the filling of the resin into the groove portion of the metal screw is performed smoothly. In addition, the lower end 18 of the shaft portion expands radially outward. Thereby, the punching strength is improved.

To attach the metal screw 1 to the resin component,
Ultrasonic vibration is used. The metal screw is press-fitted into a hole of a resin component having a tubular hole (not shown) using ultrasonic vibration, so that the resin melted by frictional heat generated between the metal screw 1 and the resin component becomes a metal screw. The outer peripheral surface of the metal screw 1 and the resin component are joined by filling the vertical groove 11 and the horizontal groove 13.

An example of a method for manufacturing the above metal screw will be described below. The metal screw 1 is formed from a single metal plate by press molding. As shown in FIG. 3, a drawing step of forming the metal plate into a cup shape through n drawing steps, a sizing step, and a punching step of making a hole in a part of the cup-shaped bottom part,
The method includes a burring step, a drawing step of forming a vertical groove, an inner diameter squeezing step, an outer diameter coining step, a flange trimming step, and a thread rolling step of forming a screw on the inner peripheral surface. The vertical groove 11 is formed by pressing a pressed product after the burring step into a forming die having a plurality of grooves extending in the axial direction formed on the inner peripheral surface. The lateral groove 13 is
In the outer diameter coining step, for example, it is formed by the shifting cam 20 shown in FIGS. A plurality of shift cams 20 are used for forming one metal screw. Each cam 20
Are annularly arranged on the circumference having the same axis as the axis of the pressed product in which the vertical groove is formed, and are driven so as to be able to advance and retreat with respect to the axis. The shift cam 20 has a plurality of protruding portions 21 protruding toward the outer peripheral surface of the pressed product, and extending in a direction intersecting with the axial direction, for forming a lateral groove on the surface facing the outer peripheral surface of the pressed product. I have. At the time of forming the lateral groove, each shift cam 20 is driven forward toward the axis, and a plurality of projections 21 provided on each shift cam 20 press the outer peripheral surface of the pressed product. As a result, the ridges 12 between the adjacent vertical grooves 11 form protrusions 21 extending in a direction intersecting the axial direction.
, And is discontinuous in the axial direction, and a plurality of lateral grooves 13 are formed. The pressed ridge 12 becomes the same plane as the bottom surface of the vertical groove 11 or a surface slightly protruding radially outward from the bottom surface of the vertical groove 11.

As shown in FIG. 6, when the projecting portion 21 extends in a direction perpendicular to the longitudinal groove 11 of the metal screw 1, the lateral groove 13 extending in the circumferential direction as shown in FIG. It is formed. Further, as shown in FIGS.
When 1 ′, 21 ″ extends obliquely with respect to the longitudinal groove of the metal screw, a lateral groove extending in a direction inclined with respect to the circumferential direction is formed. When formed in the inclined direction, the resin shearing length with respect to the punching load is increased, so that the punching strength is improved, and further, as shown in FIGS. , Α) are arranged adjacent to each other, so that a U-shaped or inverted C-shaped lateral groove is formed, and the punching strength and torque strength are improved.

As shown in FIG. 4, adjacent shifting cams 20 have a gap S between the cams. Therefore, the shifting cam 20
Is driven forward, and when the lateral groove is formed by the protruding portion 21, the gap S is formed with a crest 12 not pressed by the shift cam 20 and a crest moved as a result of being pressed by the shift cam 20. Metal material is located. as a result,
Ribs 14 are formed. The metal screw 1 is formed only from a single metal plate by press molding, and does not require a cutting process.
Since cutting chips are hardly generated during the molding process, it can be manufactured at low cost.

A punch having a substantially conical tip is provided.
By pressing against the lower end of the pressed product from below the shaft of the pressed product, the metal screw 1 whose lower end 18 is expanded can be obtained as shown in FIG.

Next, a configuration specific to each embodiment of the present invention will be described. In the first embodiment of the present invention, as shown in FIG.
2 are formed parallel to the axial direction in the lateral groove 13 formed in the circumferential direction between the two, more specifically, in the lateral groove 13 between the tops of the adjacent peaks. . Rib 1
As shown in FIG. 1, reference numerals 4 are formed in the lateral grooves 13 at the same pitch in the circumferential direction and in the same axial direction. The height of the rib 14 (the height protruding radially outward from the bottom surface 13a of the lateral groove)
The height is substantially equal to the height of the ridge 12 before the lateral groove 13 is formed. When the ribs 14 are formed by pressing, as shown in FIG. 4, push cams 20 arranged at a constant pitch in the circumferential direction are used. The gap S between the adjacent push cams 20 and the top of the peak of the pressed product are on the same straight line.
Further, since the ribs 14 are formed in the respective lateral grooves 13 in the same axial direction, the division surface 22 of the push cam 20 is flat as shown in FIG. The effect is that the height of the ribs 14 is substantially equal to the height of the peaks 12 and is high, so that high torque strength can be obtained. The push cam 20 can be easily obtained because the dividing surface 22 is a flat surface, the protrusions 21 are provided at equal pitches in the axial direction, and the shape is simple. The rib 14
Are formed at equal pitches in the circumferential direction in each lateral groove,
The torque strength of the metal screw 1 is easily stabilized in the circumferential direction.
Even if there is a portion having a low resin filling density near the hole of the resin component into which the metal screw 1 is press-fitted, ribs 14 are formed in the horizontal groove 13 at equal pitches in the circumferential direction in the metal screw 1. Therefore, the proportion of the ribs 14 of the metal screw 1 located only in the hole of the resin component having a portion where the resin filling density is low is low. On the other hand, when the ribs 14 are formed in the biased positions, all the ribs 1 of the metal screw 1 are formed in the hole of the resin component having a portion where the resin filling density is low.
4 becomes higher. Therefore, even if the metal screw having the ribs 14 formed at equal pitches in the circumferential direction is press-fitted into a resin component having a portion with a low filling density, a high torque strength can be obtained. The torsion torque of the metal screw 1 of the embodiment of the present invention coupled to the resin component was improved by about 40% as compared with the metal screw without ribs coupled to the resin component.

In the second embodiment of the present invention, as schematically shown in FIG. 10, each rib 14 is provided in each of the lateral grooves 13 except between the ridges 12 adjacent to each other in the axial direction. , Are formed parallel to the axial direction. A plurality of ribs 14 are provided in each lateral groove 13 at a constant pitch in the circumferential direction. The height of the rib 14 is set lower than the height of the ridge 12 before the lateral groove 13 is formed. The ribs 14 are not always formed in the same axial direction. FIG. 10 shows a third-stage lateral groove 13. The ribs 14 formed in the first-stage and third-stage lateral grooves 13 are in the same axial direction. The formed ribs 14 are shifted from the first and second ribs 14 in axial position. Since the ribs 14 are not always formed in the same axial direction, when the ribs 14 are formed by pressing, a plurality of push cams 2 used for forming are formed.
0 is a plane in which each adjacent plane (divided plane) is complicated and complicated. The operation is substantially the same as that of the first embodiment, and a high torque strength can be obtained.

In the third embodiment of the present invention, as schematically shown in FIG. 11, a rib 14 is provided in a lateral groove extending in the circumferential direction at a predetermined angle (θ) with respect to the axial direction (for example, θ = 15 °). )
It is formed inclined. When the ribs 14 are formed by pressing, as shown in FIG. 12, a push cam 20 having a divided surface 22 inclined in the same direction at the same angle is used. Therefore, the gap S between the respective projecting portions 21 of the adjacent push cams 20 is inclined by θ with respect to the axial direction. The effect is that the rib 14 is inclined by θ, as in the first and second embodiments.
Is higher than the metal screw 1 formed in the axial direction.

In the fourth embodiment of the present invention, as schematically shown in FIG. 13, the adjacent ribs 14 formed in the lateral grooves having the same circumference are formed in different directions in a C shape or an inverted C shape. It is inclined. The effect is that the rib 14 is inclined, as in the first and second embodiments.
As compared with the metal screw 1 in which 4 is formed in the axial direction, the punching strength is improved.

[0023]

According to the metal screw of the first to sixth aspects, the rib is formed in the lateral groove, so that the torque strength can be improved. According to the metal screw of the fourth aspect, since the rib is formed in the transverse groove in the direction intersecting in the axial direction, the torque strength is improved and the pull-out load is improved. According to the metal screw of the fifth aspect, since a plurality of ribs are formed at equal pitches in the lateral groove, the torque strength is easily stabilized. According to the metal screw of claim 6, the vertical groove,
Since the lateral grooves and ribs are formed by press molding,
It is cheaper than machining.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a half of a metal screw according to a first embodiment of the present invention in cross section.

FIG. 2 is a bottom view of the metal screw according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 4 is a diagram showing a position of a push cam for performing a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 5 is a side view of a push cam for performing a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 6 is a front view of a push cam capable of performing a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 7 is a front view of a push cam capable of implementing a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 8 is a front view of a push cam capable of performing a method of manufacturing a metal screw common to all embodiments of the present invention.

FIG. 9 is a rear view of the push cam according to the first embodiment of the present invention.

FIG. 10 is a partial side view of a metal screw according to a second embodiment of the present invention.

FIG. 11 is a partial side view of a metal screw according to a third embodiment of the present invention.

FIG. 12 is a rear view of a push cam according to a third embodiment of the present invention.

FIG. 13 is a partial side view of a metal screw according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal screw 11 Vertical groove 12 Mountain part 13 Horizontal groove 14 Rib

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norio Ito 3-41 Iwata, Makidaira, Nada-cho, Nada-gun, Aichi Prefecture Inside Takagi Seisakusho Co., Ltd. (72) Kanji Suzuki Iwata, Makihira, Nada-cho, Nada-gun, Aichi Prefecture No. 3 41 Takagi Works Co., Ltd. F term (reference) 4F211 AD24 AH06 TA01 TA06 TA14 TC07 TD02 TD15 TH17 TN22 TN77 TQ05

Claims (6)

[Claims] 1. A metal screw press-fitted into a hole of a resin component having a hole using ultrasonic vibration and coupled to the resin component on an outer peripheral surface, wherein a plurality of threads are provided on the outer peripheral surface in an axial direction. A vertical groove is formed, a plurality of horizontal grooves are formed on the outer peripheral surface in a direction intersecting the axial direction, and a rib is formed in the horizontal groove in a direction intersecting the direction in which the horizontal groove is formed. Are, metal screws. 2. The metal screw according to claim 1, wherein the rib is formed in a lateral groove in an axial direction. 3. A crest between the adjacent flutes is discontinuous in the axial direction by the lateral groove, and the crest between the crests adjacent in the axial direction. The metal screw according to claim 2, wherein the rib is formed in a lateral groove. 4. The metal screw according to claim 1, wherein the rib is formed in a transverse groove in a direction intersecting in the axial direction. 5. The metal screw according to claim 1, wherein a plurality of the ribs are formed at equal pitches in the lateral groove. 6. The metal screw according to claim 1, wherein the vertical groove, the horizontal groove, and the rib are formed by press molding.