JP3979575B2 - Self-piercing rivet pressure judgment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-piercing rivet pressure determination method for determining an excess or deficiency of pressure when a plurality of plate members are caulked to each other by self-piercing rivets.
[0002]
[Prior art]
As a method of caulking a plurality of plate materials, there is known a method of driving a self-piercing rivet into a plate material to be fastened by a fastening device having a die and a punch (see Japanese Patent Publication No. 8-505087). According to this method, as shown in FIG. 9, the tip of the leg portion L of the self-piercing rivet SPR that penetrates the upper panel UP as the plate to be fastened stays inside the lower panel LP and expands in the radial direction, and the back surface of the lower panel LP On the side, a button-like bulge B is formed. As described above, in the caulking structure using the self-piercing rivet SPR, a hole is not opened on the back surface side of the lower panel LP, so that a good appearance and sealing performance can be obtained.
[0003]
In such a caulking method using the self-piercing rivet SPR, if the pressure applied to the head H of the self-piercing rivet SPR by the punch of the fastening device is excessive or insufficient, the radial direction of the leg portion L of the self-piercing rivet SPR As a result, the caulking force between the upper panel UP and the lower panel LP varies. Also, if the pressing oil that adheres to the lower panel LP is carried and collected in the cavity recess D2 that is the pressure receiving surface of the die, depending on the combination of the material and thickness of the upper panel UP and lower panel LP, they can be caulked properly. Sometimes you can't.
[0004]
Therefore, in order to make the caulking force between the upper panel UP and the lower panel LP constant, conventionally, it is determined whether the self-piercing rivet SPR is excessive or insufficient by observing the driving state of the self-piercing rivet SPR. That is, observe whether the head H of the self-piercing rivet SPR is lifted from the surface of the upper panel UP, and compare and observe the diameter and height of the button-like bulge B formed on the back surface of the lower panel LP. It was determined whether the pressure on the self-piercing rivet SPR was excessive or insufficient.
[0005]
[Problems to be solved by the invention]
By the way, it is difficult to specify the diameter and the height of the button-like bulging portion B because the corners are round, and the observation result of the diameter and the height of the bulging portion B shows a variation by the observer. . Therefore, the method for determining the excess or deficiency of the applied pressure based on the observation result of the driving state of the self-piercing rivet SPR has a problem that the objectivity is lacking and the reliability is low.
[0006]
However, if the caulking portion by the self-piercing rivet SPR is extracted and cut by inspection and the cut surface is observed, it is possible to more objectively determine whether the pressure of the self-piercing rivet SPR is excessive or insufficient. However, there is a problem that it takes a lot of time and labor for cutting, and it is impossible to inspect all the caulking points.
[0007]
Therefore, an object of the present invention is to provide a self-piercing rivet pressure determination method that can objectively and easily determine whether the pressure of a self-piercing rivet is excessive or insufficient in all caulking portions. .
[0008]
[Means for Solving the Problems]
As a means for solving the above-described problem, the self-piercing rivet pressure determination method according to the first aspect of the present invention is the method in which a self-piercing rivet is driven between a die and a punch to the plate material to be fastened and the plate material to be fastened is mutually connected. When caulking to a pressure receiving surface of the die, a plurality of concave markings formed in advance are determined on the basis of the degree of transfer of the self-piercing rivet to the fastening plate material according to the degree of transfer. The self-piercing rivet pressure determining method is as follows: each of the markings has a difference in how the markings are transferred by changing the roundness, opening width and depth of the opening of each marking. It was formed as described above.
[0009]
In the self-piercing rivet pressure determination method according to the first aspect of the present invention, the observer visually observes the transfer degree of the marking on the fastening plate material. Then, it is objectively determined that the pressure applied to the self-piercing rivet increases as the transfer degree of the marking increases, and the pressure applied to the self-piercing rivet decreases as the transfer degree of the stamp decreases.
[0010]
The pressure deciding method of the self-piercing rivet according to the second invention is the pressure judging method according to the first invention, wherein the die has an oil relief hole or a relief groove accumulated in a cavity recess of its pressure receiving surface. Is formed, and an end of the escape hole or escape groove is opened on the pressure receiving surface to form the marking.
[0011]
In the self-piercing rivet pressure determination method according to the second aspect of the invention, the greater the degree of transfer to the plate material to be fastened by the opening of the oil escape hole or the end of the escape groove, the greater the pressure applied to the self-piercing rivet, It is objectively determined that the pressure applied to the self-piercing rivet is smaller as the transfer degree of the stamp is smaller.
[0012]
A self-piercing rivet pressure determination method according to a third aspect of the present invention is characterized in that the marking is formed by a groove formed on a ring-shaped pressure receiving surface of the die.
[0013]
In the self-piercing rivet pressure determination method according to the third aspect of the present invention, the observer visually observes the degree of transfer of the lower limit value stamp, the appropriate value stamp, and the upper limit value stamp on the fastened plate material. Then, when the stamp transferred to the fastening plate material is only the lower limit value stamp, it is determined that the pressure of the self-piercing rivet is between the lower limit value and the appropriate value. If the value is stamped, it is determined that the pressure is between the appropriate value and the upper limit value. On the other hand, when the stamp is a lower limit stamp, an appropriate value stamp, and an upper limit stamp, it is determined that the applied pressure exceeds the upper limit value, and when any stamp is not transferred, It is determined that the pressure does not reach the lower limit value.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a self-piercing rivet pressure determination method according to the present invention will be described below with reference to the drawings. In the drawings to be referred to, FIG. 1 is a perspective view of a fastening device used in the self-piercing rivet pressure determination method of the present invention, and FIG. 2 is a sectional view of an upper panel and a lower panel that are crimped by the self-piercing rivet shown in FIG. FIG. 3 is a perspective view of a die used in the method for determining the pressure of the self-piercing rivet according to the first embodiment of the present invention.
[0015]
The self-piercing rivet pressure determination method according to the first embodiment is shown in FIG. 2 for the upper panel UP and the lower panel LP that are stacked as the fastening plates between the die D and the punch P of the fastening device 1 shown in FIG. As shown in the figure, when the self-piercing rivet SPR is driven and caulked, the magnitude of the applied pressure of the self-piercing rivet SPR is determined.
[0016]
As shown in an enlarged view in FIG. 3, the die D is formed in a stepped short column shape in which a small-diameter portion is continuous with a lower portion of the large-diameter portion. A ring-shaped pressure receiving surface D <b> 1 that contacts the back surface of the illustrated lower panel LP is formed. A cavity recess D2 into which the lower panel LP and the upper panel UP flow in by plastic flow in response to the driving of the self-piercing rivet SPR shown in FIG. 2 is formed inside the ring-shaped pressure receiving surface D1. In the central portion of the cavity recess D2, a raised portion D3 is formed in a gentle chevron for expanding the distal end portion of the leg portion L of the self-piercing rivet SPR shown in FIG. 2 in the radial direction.
[0017]
Here, on the ring-shaped pressure receiving surface D1 at the upper end surface of the die D, a transferable stamp is formed on the back surface of the lower panel LP pressed between the punch P shown in FIG. This stamp corresponds to the magnitude of the pressure applied to the head H of the self-piercing rivet SPR by the punch P shown in FIG. 2, for example, a pressure greater than or equal to the lower limit value of the appropriate pressure range, or greater than the intermediate appropriate value. The lower limit value stamp S1, the appropriate value stamp S2, and the upper limit value stamp S3, which are respectively transferred to the lower panel LP with a pressing force of not less than the upper limit value, are formed.
[0018]
The lower limit value stamp S1, the appropriate value stamp S2, and the upper limit value stamp S3 may have a convex shape, but are formed in a concave shape in the illustrated example. Specifically, the lower limit value stamp S1 is formed in a triangular recess Δ, the appropriate value stamp S2 is formed in a circular recess ○, and the upper limit value stamp S3 is formed in a square recess □.
[0019]
By the way, in the concave-shaped engraving, as the corner of the opening is smaller, the opening width is larger, and the depth is shallower, the bottom shape is more easily transferred to the lower panel LP, and conversely, the corner of the opening is larger. As the opening width is smaller and the depth is deeper, the bottom shape tends to be difficult to be transferred to the lower panel LP. Therefore, as shown in FIG. 4 (a), the lower limit value marking S1 made of the triangular recess Δ is more open than the appropriate value marking S2 made of the circular recess ○ shown in FIG. 4 (b). It is formed by reducing the roundness of the corners of the part, increasing the opening width, and decreasing the depth. Further, as shown in FIG. 4C, the upper limit value marking S3 made of the square recess □ is larger than the appropriate value marking S2 made of the circular recess ○ shown in FIG. The corners are rounded, the opening width is small, and the depth is deep.
[0020]
Next, a method for determining the pressure of the self-piercing rivet SPR using the lower limit stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 of the die D as described above will be described.
[0021]
First, when the punch P of the fastening device 1 shown in FIG. 1 is pushed to the die D side and the self-piercing rivet SPR is driven from the upper panel UP side to the lower panel LP side, the legs of the self-piercing rivet SPR are shown in FIG. The part L bites into the lower panel LP from the upper panel UP, and a part of the lower panel LP pressed by the self-piercing rivet SPR plastically flows together with a part of the upper panel UP and flows into the cavity recess D2 of the die D. The raised portion D3 formed in the central portion of the cavity concave portion D2 pushes a part of the lower panel LP into the inside of the leg portion L of the self-piercing rivet SPR, so that the tip portion of the leg portion L is expanded in the radial direction. It is done. As a result, the tip end portion of the leg portion L of the self-piercing rivet SPR remains inside the lower panel LP without penetrating.
[0022]
In the work process by the fastening device 1, the upper panel UP and the lower panel LP are sandwiched between the die D and the punch P and pressed up and down to be formed on the ring-shaped pressure receiving surface D 1 of the die D. The lower limit value stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 are pressed against the back surface of the lower panel LP. Therefore, in the self-piercing rivet pressure determination method of the first embodiment, the transfer degrees of the lower limit stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 on the back surface of the lower panel LP are visually observed.
[0023]
Here, when the stamp transferred on the back surface of the lower panel LP is only the lower limit stamp S1, it is determined that the pressure of the self-piercing rivet SPR is between the lower limit and the appropriate value. In this determination, it is preferable to determine whether or not the triangular bottom shape of the lower limit value marking S1 is well transferred. When the transferred stamps are the lower limit stamp S1 and the appropriate value stamp S2, it is determined that the pressure of the self-piercing rivet SPR is between the proper value and the upper limit. On the other hand, when the transferred stamps are the lower limit stamp S1, the appropriate stamp S2, and the upper limit stamp S3, it is determined that the pressure of the self-piercing rivet SPR exceeds the upper limit. Further, when none of the lower limit value stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 is transferred, it is determined that the pressure applied to the self-piercing rivet SPR is less than the lower limit value.
[0024]
As described above, in the self-piercing rivet pressure determination method of the first embodiment, the pressure of the self-piercing rivet SPR is determined depending on whether or not the lower limit value stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 are transferred to the back surface of the lower panel LP. Therefore, it is possible to objectively and easily determine whether the pressure of the self-piercing rivet SPR is excessive or insufficient. In addition, since the presence or absence of the transfer of the lower limit value stamp S1, the appropriate value stamp S2, and the upper limit value stamp S3 can be determined only by visual observation, it is determined whether the pressure applied to the self-piercing rivet SPR is excessive or insufficient at all caulking portions. Can do.
[0025]
Note that the lower limit value stamp S1, the appropriate value stamp S2, and the upper limit stamp S3 of the die D used in the self-piercing rivet pressure determination method of the first embodiment can be changed to appropriate shapes. For example, as shown in FIG. 5, three types of grooves having different opening widths and depths may be formed on the ring-shaped pressure receiving surface D1 for marking. In this case, the groove having the widest opening width and the shallowest depth is designated as the lower limit value stamp S4, and the groove having the narrowest opening width and the deepest depth is designated as the upper limit value stamp S6. The groove is designated as an appropriate value stamp S5.
[0026]
Even when such lower limit value stamp S4, appropriate value stamp S5 and upper limit value stamp S6 are used, the presence or absence of transfer of lower limit value stamp S4, appropriate value stamp S5 and upper limit value stamp S6 on the back surface of lower panel LP is visually observed. By doing so, it is possible to objectively and easily determine whether the pressure of the self-piercing rivet SPR is excessive or insufficient. Incidentally, in the grooves constituting the lower limit value stamp S4, the appropriate value stamp S5 and the upper limit value stamp S6, the pressing oil adhered to the lower panel LP shown in FIG. 1 is carried into the cavity recess D2 shown in FIG. If it accumulates, it also functions as a relief groove.
[0027]
Next, a method for determining the pressure applied to the self-piercing rivet according to the second embodiment will be described. In the self-piercing rivet pressure determination method of the second embodiment, a die D as shown in FIG. 6 is used. In the cavity recess D2 that is the pressure receiving surface of the die D, when oil for press adhering to the lower panel LP shown in FIG. 2 accumulates in the cavity recess D2, for example, the oil is released from the inside of the cavity recess D2. Three relief grooves G1, G2, and G3 are formed, and the upper end portions thereof are opened in the inner peripheral portion of the ring-shaped pressure receiving surface D1, thereby forming a stamp.
[0028]
The three escape grooves G1, G2, and G3 are of three types having different opening widths and depths, and the upper end opening of the escape groove G1 having the largest opening width and depth is designated as the lower limit value marking S7. The upper end opening of the clearance groove G3 having the smallest opening is defined as the upper limit value marking S9, and the upper end opening of the clearance groove G2 having the middle opening width and depth is defined as the appropriate value marking S8.
[0029]
In the self-piercing rivet pressure determination method of the second embodiment using the lower limit stamp S7, the appropriate value stamp S8, and the upper limit stamp S9 formed on the die D, the lower limit stamp on the back surface of the lower panel LP is used. By visually observing the presence or absence of transfer of S7, appropriate value stamp S8 and upper limit stamp S9, it is possible to objectively and easily determine whether the pressure of the self-piercing rivet SPR is excessive or insufficient. In addition, the pressing oil that is attached to the lower panel LP and carried into the cavity recess D2 escapes when a part of the lower panel LP flows into the cavity recess D2 by plastic flow as shown in FIG. Since it is pushed out from the upper end opening through the grooves G1, G2, G3, the lower panel LP is surely plastically flowed into the cavity recess D2 in response to the driving of the self-piercing rivet SPR, and the upper panel UP and the lower panel LP are securely caulked. Can be attached.
[0030]
In addition, instead of the lower limit value stamp S7, the appropriate value stamp S8, and the upper limit value stamp S9 of the die D used in the method for determining the pressure of the self-piercing rivet of the second embodiment, for example, as shown in FIG. The upper end portions of the oil escape holes H1 and H2 may be opened on the bottom surface of the cavity recess D2 to form the marking. In this case, the upper end opening of the escape hole H1 having a large opening diameter is set as a lower limit value stamp S10, and the upper end opening of the escape hole H2 having a small opening diameter is set as an upper limit value stamp S11.
[0031]
Even when such lower limit stamp S10 and upper limit stamp S11 are used, the self-piercing rivet SPR can be added by visually observing whether or not the lower limit stamp S10 and the upper limit stamp S11 are transferred to the back surface of the lower panel LP. It is possible to objectively and easily determine whether the pressure is excessive or insufficient.
[0032]
In the fastening device 1 shown in FIG. 1, in order to clarify the combination of the die D and the self-piercing rivet SPR used according to the plate thickness of the upper panel UP and the lower panel LP, the ring-shaped pressure receiving surface D1 of the die D is provided. A stamp corresponding to the stamp to be formed can be provided on the head H of the self-piercing rivet SPR. FIG. 8 shows an example of this, and as shown in FIG. 8 (a), the ring-shaped pressure receiving surface D1 of the shallow die D of the cavity recess D2 is provided with a rectangular mark for determining the pressure applied by the self-piercing rivet SPR. A square marking is also formed on the head H of the self-piercing rivet SPR having a short leg L corresponding to the die D. Further, as shown in FIG. 8B, a circular stamp for determining the pressure applied to the self-piercing rivet SPR is formed on the ring-shaped pressure receiving surface D1 of the die D deep in the cavity recess D2, and this die D A circular inscription is also formed on the head H of the self-piercing rivet SPR having a long leg L corresponding to.
[0033]
A plurality of stamps may be formed on the head H of the self-piercing rivet SPR so as to indicate the length of the leg portion L by the number of stamps.
[0034]
【The invention's effect】
As described above, in the self-piercing rivet pressure determination method according to the first aspect of the present invention, the degree of transfer of the marking on the fastening plate material is visually observed by an observer. Then, it is determined that the pressure applied to the self-piercing rivet increases as the transfer degree of the marking increases, and the pressure applied to the self-piercing rivet decreases as the transfer degree of the stamp decreases. Therefore, according to this pressure determination method, it is possible to objectively and easily determine whether the self-piercing rivet is excessive or insufficient in all the caulking portions.
[0035]
In the self-piercing rivet pressure determination method according to the second aspect of the invention, the greater the degree of transfer to the plate material to be fastened by the opening of the oil escape hole or the end of the escape groove, the greater the pressure applied to the self-piercing rivet, It is objectively determined that the pressure applied to the self-piercing rivet is smaller as the transfer degree of the stamp is smaller. Therefore, according to this pressure determination method, it is possible to objectively and easily determine whether the self-piercing rivet is excessive or insufficient in all the caulking portions. In addition, since the oil escape hole or escape groove is formed in the die used in this pressure determination method, the plate material to be fastened is surely plastically flowed into the cavity recess according to the driving of the self-piercing rivet, The fastened plate material can be securely crimped.
[0036]
In the self-piercing rivet pressure determination method according to the third aspect of the present invention, the observer visually observes the degree of transfer of the lower limit value stamp, the appropriate value stamp, and the upper limit value stamp on the fastened plate material. When the stamp transferred on the fastening plate material is only the lower limit value stamp, it is determined that the pressure of the self-piercing rivet is between the lower limit value and the appropriate value. If the value is stamped, it is determined that the pressure is between the appropriate value and the upper limit value. On the other hand, when the stamp is a lower limit stamp, an appropriate value stamp, and an upper limit stamp, it is determined that the applied pressure exceeds the upper limit value, and when any stamp is not transferred, It is determined that the pressure does not reach the lower limit value. Therefore, according to this pressure determination method, it is possible to more clearly determine whether the self-piercing rivet is excessive or insufficient.
[Brief description of the drawings]
FIG. 1 is a perspective view of a fastening device used in a method for determining pressure applied to a self-piercing rivet according to the present invention.
2 is a cross-sectional view of an upper panel and a lower panel that are crimped by a self-piercing rivet shown in FIG. 1. FIG.
FIG. 3 is a perspective view of a die used in the pressure determination method for a self-piercing rivet according to the first embodiment of the present invention.
4 is a cross-sectional view showing the comparison of the roundness, opening width, and depth of the corners of the opening of the lower limit marking, the appropriate value marking, and the upper limit marking shown in FIG. 3;
FIG. 5 is a perspective view of a die showing a modified example of the marking used in the method for determining the pressure of the self-piercing rivet according to the first embodiment.
FIG. 6 is a perspective view of a die used in a method for determining a pressure applied to a self-piercing rivet according to a second embodiment.
FIG. 7 is a cross-sectional view of a die showing a modification of the marking used in the method for determining the pressure applied to the self-piercing rivet according to the second embodiment.
FIG. 8 is a perspective view of the die and self-piercing rivet showing the indicia formed to clarify the combination of the die and self-piercing rivet shown in FIG.
FIG. 9 is a cross-sectional view of an upper panel and a lower panel showing a caulking structure using self-piercing rivets.
[Explanation of symbols]
1: Fastening device D: Die D1: Ring-shaped pressure receiving surface D2: Cavity recess D3: Raised portions S1, S4, S7, S10: Lower limit value stamps S2, S5, S8: Appropriate value stamps S3, S6, S9, S11: Upper limit Value stamp G1, G2, G3: Escape groove H1, H2: Escape hole P: Punch SPR: Self-piercing rivet H: Head L: Leg UP: Upper panel LP: Lower panel

Claims (3)

When a self-piercing rivet is driven between a die and a punch to squeeze the fastening plate material, a plurality of concave marks formed in advance on the pressure receiving surface of the die are fastened. a pressure determination method of self-piercing rivets, characterized by determining the magnitude of the pressure force of the self-piercing rivet according to the degree to be transferred to the plate,
Each of the inscriptions is formed by changing the roundness, opening width, and depth of the opening of each inscription so that the transfer of each inscription is different. Pressure judgment method.   The die has a relief hole or relief groove for oil accumulated in the cavity recess of the pressure receiving surface, and an end of the relief hole or relief groove is opened in the pressure receiving surface to form the inscription. The self-piercing rivet pressure determination method according to claim 1, wherein: The self-piercing rivet pressure determination method according to claim 1, wherein the marking is formed by a groove formed on a ring-shaped pressure receiving surface of the die.

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