JP7129368B2 - Mechanical clinch device for plate-like members - Google Patents

Description

The present invention relates to a mechanical clinch device for plate-like members.

BACKGROUND ART In the technical field, a so-called "caulking method", which is a type of mechanical fastening method that does not rely on welding or adhesion, is known as a method for joining plate-like members in an automobile body or the like. In addition, among the crimping methods, the "mechanical clinch method" is widely used, which can fasten plate-like members only by plastic deformation of the plate-like members without using other members such as rivets (for example, patent documents 1).

In the mechanical clinch method, as is well known to those skilled in the art, for example, a stacked plate-like member is punched from above to form a concave shape, and the upper plate-like member is attached to another plate adjacent to the lower side. In the inside of the shaped member, plastic flow is caused to the outside in the radial direction. As a result, a so-called "interlock portion" is formed in which the materials forming the two adjacent plate-shaped members are engaged with each other, and these plate-shaped members are fastened together.

In order to improve the fastening force between plate-shaped members by the mechanical clinch method as described above, the side surface of the recess formed by punching (hereinafter sometimes referred to as the “side surface of the recess”) has a plate-shaped surface. It is desirable to increase the thickness of the member and the depth of meshing between the plate-like members at the interlock portion (hereinafter sometimes referred to as "interlock amount").

Therefore, in this technical field, a wide variety of techniques have been proposed for the purpose of further improving the fastening force between plate members by the mechanical clinch method. For example, FIG. 13 is a schematic diagram showing an example of the configuration and operation of a conventional mechanical clinch device (hereinafter sometimes referred to as “conventional device”).

In the conventional device 200 illustrated in FIG. 13, as shown in (a), movable blades 6 are dividedly arranged on the outer periphery of a die (fixed anvil 5) having a concave conical surface toward the metal plate at the tip end. Two metal plates 1 and 2 are placed on top of each other, and the metal plates 1 and 2 are sandwiched and fixed between a stripper 4 and a blade 6. - 特許庁After that, as shown in (b), a cylindrical punch 3 having a convex conical surface at the tip is locally pushed into the metal plate from above, thereby plastically deforming the upper metal plate 1 and moving the blade 6. The lower metal plate 2 is plastically deformed by letting it escape in the outer peripheral direction, and the upper and lower metal plates are mechanically joined. As a result, the material forming the plate member (metal plate 2) below the interlock portion protrudes outward in the radial direction by a large amount, thereby expanding the interlock portion in the radial direction and increasing the fastening force. (See Patent Document 2, for example).

In addition, the die is composed of a first die that constitutes the axial center of the die and a second die that constitutes the outer periphery of the die, and after the first die is driven, the second die is driven into the die side of the interlock portion. A mechanical clinch construction method has been proposed (see Patent Document 3, for example). According to the mechanical clinch method, by driving the second die, the die-side portion of the interlock portion plastically flows outward in the radial direction, the interlock portion expands in the radial direction, and the plate shape on the side surface of the recess becomes The thickness of the member increases. As a result, the fastening force between the plate members can be increased.

However, in the mechanical clinch method as described above, a complex movable mechanism such as a blade configured to be movable in the radial direction and a die composed of a first die and a second die, and precise control of the movable mechanism is required. This may lead to problems such as an increase in manufacturing cost and complication of maintenance, for example. In addition, since the amount of overhang on the lower side of the interlock portion is increased, there is a possibility that it may lead to problems such as interference with other surrounding members and deterioration of aesthetics.

By the way, depending on the properties of the plate-like member, defects such as reduction in the thickness of the plate-like member or cracks or cuts may occur on the side surface of the concave portion as the punch is driven. Such defects lead to problems such as, for example, a decrease in the amount of interlocking and a decrease in fastening force between plate members. Therefore, a technology has been proposed to reduce the above defects by preheating the portion of the plate-shaped member where the punch is driven by irradiating the laser beam, thereby promoting the plastic flow of the plate-shaped member. (See Patent Document 4, for example). However, this technique has problems such as an increase in energy consumption in addition to problems such as complication of the configuration and control of the processing apparatus.

In addition, the reduction in the thickness of the plate-like member on the side surface of the concave portion as described above, or defects such as cracks or cuts, occur in the plate-like member on the die side more than the plate-like member on the punch side. becomes more pronounced when it is likely to occur. Specific examples of such a case include, for example, a case in which the die-side plate-like member is softer than the punch-side plate-like member, and a case in which the die-side plate-like member is softer than the punch-side plate-like member. A case where the thickness is thicker can be mentioned.

U.S. Pat. No. 4,760,634 JP 2009-274119 A Japanese Patent Application Laid-Open No. 2001-200813 JP 2019-000883 A

As described above, in the technical field, plate-shaped members can be formed by plastic deformation of a plate-shaped member only by a simple structure without using any other member such as a rivet, without requiring a complicated structure and/or control. There is a need for a mechanical clinch device capable of increasing the fastening force between members. Furthermore, even if the plate-like member on the die side is more susceptible to plastic flow due to the punching than the plate-like member on the punch side, the thickness of the plate-like member may be reduced on the side surface of the recess, or cracks or cuts may occur. There is a demand for a mechanical clinch device capable of increasing the fastening force between plate members while reducing defects.

In view of the above problems, as a result of intensive research, the present inventors have found that in a mechanical clinch device for fastening a plurality of plate-shaped members by a mechanical clinch method, the distance between the tip surface of the punch and the top surface of the die facing each other is It has been found that the above requirement can be met by structuring such that the distance from the center of the top face to the outside becomes smaller.

Specifically, the mechanical clinch device for a plate-like member according to the present invention (hereinafter sometimes referred to as the "apparatus of the present invention") is a plate-like member provided with a punch and a die facing each other so as to approach and move away from each other. It is a mechanical clinch device. The tip of the punch is formed with a tip surface facing the die. A cavity that opens toward the punch is formed at the tip of the die, and a protrusion that protrudes from the bottom surface of the cavity toward the punch is formed inside the cavity. , and a top surface, which is a surface facing the tip surface of the punch. In addition, in the apparatus of the present invention, a plurality of plate-like members are separated by striking a punch into the laminated portion where a plurality of plate-like members overlap and sandwiching the laminated portion between the tip surface of the punch and the top surface of the die. configured to be closed.

Furthermore, in the apparatus of the present invention, the top surface of the convex portion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip end surface of the punch and the top surface of the die is radially from the center of the top surface. is configured to become smaller toward the outside.

Preferably, the top surface of the die is formed as a concave spherical surface, the tip surface of the punch is formed as a convex spherical surface, and the radius of curvature r1 of the tip surface is larger than the radius of curvature r2 of the top surface.

According to the apparatus of the present invention, plate-like members can be fastened only by plastic deformation of the plate-like members with a simple structure without requiring complicated structure and/or control without using other members such as rivets. power can be increased. In addition, even if the plate-like member on the die side is more susceptible to plastic flow due to the punching than the plate-like member on the punch side, the thickness of the plate-like member may be reduced on the side surface of the recess, or cracks or cuts may occur. It is possible to increase the fastening force between the plate members while reducing defects.

Other objects, features and attendant advantages of the present invention will be readily understood from the description of each embodiment of the present invention described with reference to the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a configuration of a punch included in a mechanical clinch device (first device) for a plate member according to a first embodiment of the present invention; It is a schematic diagram which shows an example of a structure of the dice with which a 1st apparatus is provided. FIG. 3 is a schematic partial cross-sectional perspective view showing a state in which the punches and dies shown in FIGS. 1 and 2 are incorporated in a first device; 4 is a schematic partial cross-sectional side view of the punch and die shown in FIG. 3 as viewed from a direction perpendicular to a common axis; FIG. It is typical sectional drawing which shows a mode that the plate-shaped member of 2 sheets is fastened by the mechanical clinch construction method in a 1st apparatus in steps. FIG. 4 is a schematic cross-sectional view showing a specific example of the shape of the top surface of the die provided in the first device; FIG. 5 is a schematic cross-sectional view showing a specific example of the shape of the tip surface of the punch provided in the second device; FIG. 10 is a schematic cross-sectional view showing a specific example of a combination of shapes of the tip end surface of the punch and the top surface of the die provided in the second device; 2 is a schematic cross-sectional view showing a fastening portion between a first member and a second member formed by a mechanical clinch device (example device) according to an example of the present invention in Example 1. FIG. FIG. 2 is a schematic cross-sectional view showing a fastening portion between a first member and a second member formed by a mechanical clinch device (comparative example device) according to a comparative example of conventional technology in Example 1; FIG. 8 is a schematic cross-sectional view showing a fastening portion between a first member and a second member formed by a mechanical clinch device (example device) according to an example of the present invention in Example 2; FIG. 7 is a schematic cross-sectional view showing a fastening portion between a first member and a second member formed by a mechanical clinch device (comparative example device) according to a conventional comparative example in Example 2; It is a schematic diagram which shows an example of a structure and operation|movement of the mechanical clinch apparatus (conventional apparatus) which concerns on a prior art. It is a schematic diagram which shows an example of a structure of the punch with which a conventional apparatus is provided. FIG. 3 is a schematic diagram showing an example of the configuration of a die provided in a conventional device; FIG. 16 is a schematic partial cross-sectional perspective view showing a state in which the punches and dies shown in FIGS. 14 and 15 are incorporated in a conventional device; FIG. 17 is a schematic partial cross-sectional side view of the punch and die shown in FIG. 16 when viewed from a direction perpendicular to a common axis; It is typical sectional drawing which shows in steps how two plate-shaped members are fastened by the mechanical clinch construction method in a conventional apparatus.

<<1st Embodiment>>
Various embodiments of the mechanical clinch device for plate-like members (hereinafter sometimes referred to as "first device") according to the first embodiment of the present invention will be described below. Problems associated with the mechanical clinch device for plate members (conventional device) will be described.

<Configuration of conventional device>
(a) of FIG. 14 is a schematic side view showing an example of the configuration of a punch provided in a conventional device, and (b) is surrounded by a thick dashed line of the tip portion 211 of the punch 210 shown in (a). 1 is an enlarged view of a portion; FIG. A distal end surface 212 is formed as a flat surface on a distal end portion 211 of a punch 210 illustrated in FIG. 14 .

Next, (a) of FIG. 15 is a schematic perspective view showing an example of the configuration of a die provided in a conventional device, and (b) is a schematic view of the tip of the die 220 shown in (a). It is a front view. Also, (c) is a cross-sectional view of the die 220 along a plane including the axis of the die 220, and (d) is an enlarged view of the portion surrounded by the thick broken line at the tip of the die 220 shown in (c). is. As shown in (c) and (d), the tip of the die 220 is formed with a cavity 221 that opens toward the punch 210 side. Further, inside the cavity 221, a protrusion 222 is formed that protrudes from the bottom surface of the cavity 221 toward the punch 210 (in a state incorporated in a conventional device). Furthermore, the tip of the projection 222 is formed with a top surface 223 that faces the tip surface 212 of the punch 210 (in a state of being assembled in a conventional device).

Next, FIG. 16 is a schematic partial cross-sectional perspective view showing a state in which the punch 210 and the die 220 are incorporated in the conventional device 201, and FIG. 3 is a schematic partial cross-sectional side view when the punch 210 and the die 220 are observed from a direction perpendicular to the axis AX; FIG. Although the name "punch 210" is used in the following description, parts of the punch 210 other than the tip portion 211 are omitted in FIGS. 16 and 17. FIG.

In the example shown in FIGS. 16 and 17, the punch 210 is accommodated in a cylindrical space formed in the center of the punch holder 213 and driven by a driving device (not shown) to move the die 220 along the direction of the axis AX. It is configured to approach and separate. A tip portion of the die 220 is composed of a central portion 220a and a peripheral edge portion 220b. The center portion 220 a constitutes the bottom side of the cavity 221 and the convex portion 222 , and the peripheral portion 220 b constitutes the side surfaces and peripheral portions of the cavity 221 and the outer peripheral surface of the die 220 . However, the central portion 220a and the peripheral edge portion 220b do not necessarily have to be formed as separate members, and the die 220 may be formed as a continuous integral body.

In the conventional device 201 shown in FIGS. 16 and 17, a punch holder 213 and a laminate composed of a first member 301 that is a plate member on the punch 210 side and a second member 302 that is a plate member on the die 220 side. It is sandwiched between and fixed to the peripheral edge portion 220b of the die 220 . Then, the front end portion 211 of the punch 210 is driven from the first member 301 side by the above-described driving device, and the laminated body composed of the first member 301 and the second member 302 is formed by the front end surface 212 of the punch 210 and the top surface 223 of the die 220 . sandwiched between Thereby, the 1st member 301 and the 2nd member 302 are fastened by what is called a "mechanical clinch construction method."

FIG. 18 is an enlarged view of a portion surrounded by a thick dashed line in FIG. 17, showing the process of fastening the first member 301 and the second member 302 by the mechanical clinch method in the conventional device 201 having the configuration described above. is divided into five situations from (a) to (e) and represented step by step. (a) shows the situation when the tip portion 211 of the punch 210 comes into contact with the first member 301 fixed between the punch holder 213 and the peripheral edge portion 220b of the die 220. FIG. Next, in (b), the tip portion 211 is further pushed toward the cavity 221 of the die 220 to bend the laminate composed of the first member 301 and the second member 302 , and as a result, the second member 302 is bent into the die 220 . comes into contact with the top surface 223 of the . Therefore, during the period from (a) to (b), the laminate composed of the first member 301 and the second member 302 is subjected to bending.

Next, (c) shows a situation in which the tip portion 211 is further pushed in and a recess is being formed in the laminate composed of the first member 301 and the second member 302 . In addition to the bending process, the laminated body under this condition is subjected to a so-called "bulging process" in which the tip portion 211 is pressed to crush the laminated portion and cause plastic flow outward in the radial direction. Next, in (d), the tip portion 211 is further pushed in and the overhanging process further progresses, and the first member 301 enters the second member 302 to form an interlock portion, which is a portion where they are engaged with each other. represents the situation immediately before Finally, (e) represents the state in which the impacting of the tip 211 of the punch 210 is completed and the interlock portion is formed.

As described above, in order to improve the fastening force between the plate-like members by the mechanical clinch method as described above, the thickness of the plate-like member on the side surface of the recess formed by punching (the side surface of the recess) and the interlock It is desirable to increase the depth of engagement (interlock amount) between the plate-like members at the portion. However, for example, when the plate-like member on the die side is more likely to undergo plastic flow due to the impact of the punch than the plate-like member on the punch side, the thickness of the plate-like member is reduced, cracked, or cut on the side surface of the recess. defects tend to occur. Specific examples of such a case include, for example, a case in which the die-side plate-like member is softer than the punch-side plate-like member, and a case in which the die-side plate-like member is softer than the punch-side plate-like member. A case where the thickness is thicker can be mentioned.

Here, in the example shown in FIG. 18, when the second member 302 located on the die side is more likely to cause plastic flow than the first member 301 located on (the tip portion 211 of) the punch 210 (for example, , the second member 302 is softer or thicker than the first member 301, etc.). In this case, since the first member 301 is crushed less than the second member 302 in the process from (a) to (d) as the punch 210 is driven, plastic flow is performed outward in the radial direction. The first member 301 is also reduced. As a result, the first member 301 is locally stretched on the side surface of the recess, so that the thickness of the first member 301 is reduced or the first member 301 is broken. Moreover, since the interlock amount is also reduced, the fastening force between the first member 301 and the second member 302 is also reduced.

In order to increase the amount of interlocking in the case described above, it is necessary to strike the punch 210 deeper to increase the amount of crushing of the first member 301 . However, driving the punch 210 deeper leads to a further decrease in the thickness of the first member 301 and the second member 302 on the side surface of the recess.

As described above, in the conventional apparatus, while reducing defects such as reduction in thickness of the plate-like member on the side surface of the recess or cracking or cutting, a simple configuration does not require a complicated configuration and / or control. It is difficult to increase the fastening force between plate-like members only by plastic deformation of the plate-like members without using other members such as rivets.

<Configuration of the first device>
Therefore, in the mechanical clinch device (first device) for a plate-like member according to the first embodiment of the present invention, as described above, the distance between the tip surface of the punch and the top surface of the die facing each other is the top. The above problem is solved by structuring such that the distance from the center of the surface to the outside becomes smaller.

Specifically, the first device is a plate-like member mechanical clinch device provided with a punch and a die facing each other in a freely approachable/separable manner, and basically has the same configuration as the conventional device described above. Therefore, descriptions of structures well known to those skilled in the art, such as a mechanism for supporting a punch and a die so as to face each other so that they can approach and separate from each other, may be omitted.

The tip of the punch is formed with a tip surface facing the die. The die is formed with a cavity that opens toward the punch, and inside the cavity is formed a convex portion that protrudes from the bottom surface of the cavity toward the punch. Thus, the fact that the protrusion is formed inside the cavity means that the protrusion does not protrude outside the cavity, and the height of the protrusion from the bottom surface of the cavity is the depth of the cavity (punch and die). is less than or equal to the depth in the approaching/separating direction. Although the shape of the protrusion is not particularly limited, it is typically shaped like a truncated cone because it must withstand the impact and pressing force when the punch is driven.

A top surface, which is a surface facing the tip surface of the punch, is formed at the tip of the projection. Further, since the protrusion protrudes from the bottom surface of the cavity, the periphery of the protrusion on the bottom surface is lower than the top surface of the protrusion, and has a groove-like shape surrounding the protrusion. As a result, it is possible to receive the material forming the plate-like member that plastically flows as the punch is driven, thereby reducing the resistance to the punch driving and promoting the formation of the interlock portion. In addition, regarding the overall shape, structure, materials, etc. of the punch and die, for example, the design and specifications of the first device in which the punch and die are incorporated, and the shape, structure, material, etc. of the member to be fastened by the first device determined as appropriate depending on

In addition, the first device strikes a punch into the laminated portion where the plurality of plate-like members overlap, and sandwiches the laminated portion between the tip surface of the punch and the top surface of the die, thereby punching the plurality of plate-like members. configured to be closed. The number of plate-shaped members forming the laminated portion is not particularly limited as long as it is plural (that is, two or more), but is typically two. Also, the thickness and material of each plate-like member are not particularly limited, but typically each plate-like member is a metal plate.

The act of striking the stack with a punch to sandwich the stack between the tip surface of the punch and the top surface of the die may be accomplished by bringing the punch close to the die fixed in place, or This may be accomplished by bringing both the punch and die close together to sandwich the stack at a given location. The driving device and associated mechanisms for bringing the punch and the die closer together and away from each other are well known to those skilled in the art, and therefore descriptions thereof will be omitted here.

Furthermore, in the first device, the top surface of the convex portion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip surface of the punch and the top surface of the die is in the radial direction from the center of the top surface. is configured to become smaller toward the outside. The specific shape of the top surface formed as a concave surface is not particularly limited, as long as the distance between the tip surface and the top surface is configured to decrease radially outward from the center of the top surface. . The "distance between the tip surface of the punch and the top surface of the die" referred to here is the distance between the tip surface of the punch and the top surface of the die in the direction in which the punch and the die approach or separate. .

Here, one specific example of the first device will be described in more detail with reference to the drawings. FIG. 1(a) is a schematic side view showing an example of the configuration of the punch provided in the first device, and FIG. FIG. 4 is an enlarged view of a cut portion; The tip end portion 111 of the punch 110 illustrated in FIG. 1 has the tip end face 112 formed as a spherical surface having a radius of curvature r1, but the shape of the tip end face 112 is not limited to this as long as the above requirements are met. For example, it may be a curved surface other than a spherical surface, or it may be a flat surface.

Next, (a) of FIG. 2 is a schematic perspective view showing an example of the configuration of the die provided in the first device, and (b) is a schematic view of the tip of the die 120 shown in (a). It is a front view. Also, (c) is a cross-sectional view of the die 120 along a plane including the axis of the die 120, and (d) is an enlarged view of the portion surrounded by the thick broken line at the tip of the die 120 shown in (c). is. As shown in (c) and (d), the tip of the die 120 is formed with a cavity 121 that opens toward the punch 110 side. Further, inside the cavity 121, a convex portion 122 is formed that protrudes from the bottom surface of the cavity 121 toward the punch 110 (when assembled in the first device). Further, the tip of the projection 122 is formed with a top face 123 that faces the tip face 112 of the punch 110 (in the state of being incorporated in the first device).

The top surface 223 of the projection 222 provided in the above-described conventional device 201 is formed as a flat surface, whereas the top surface 123 of the projection 122 provided in the first device 101 is formed as a concave surface. As will be described in detail later, in the above-described conventional device 201, the distance between the tip surface 212 and the top surface 223 is constant at any position on the top surface 223, whereas the first device In 101, the distance between the tip surface 112 and the top surface 123 is configured to become smaller as it goes radially outward from the center of the top surface 123 .

Next, FIG. 3 is a schematic partial cross-sectional perspective view showing a state in which the punch 110 and the die 120 are assembled in the first device 101, and FIG. 2 is a schematic partial cross-sectional side view when the punch 110 and the die 120 are observed from a direction perpendicular to the axis AX of FIG. As shown in FIGS. 1-4, typically the punch 110 and the die 120 each have a generally cylindrical appearance and are coaxially (i.e., having a common axis AX) in the first apparatus. placed. Although the name "punch 110" is used in the following description, parts other than the tip portion 111 of the punch 110 are omitted in FIGS.

In the example shown in FIGS. 3 and 4, the punch 110 is accommodated in a cylindrical space formed in the center of the punch holder 113 and driven by a driving device (not shown) to move the die 120 along the direction of the axis AX. It is configured to approach and separate. A tip portion of the die 120 is composed of a central portion 120a and a peripheral edge portion 120b. The central portion 120 a constitutes the bottom side of the cavity 121 and the convex portion 122 , and the peripheral portion 120 b constitutes the side surfaces and peripheral portions of the cavity 121 and the outer peripheral surface of the die 120 . However, the central portion 120a and the peripheral portion 120b do not necessarily have to be formed as separate members, and the die 120 may be formed as a continuous integral body comprising the central portion 120a and the peripheral portion 120b.

In the first device 101 shown in FIGS. 3 and 4, a punch holder 113 is a laminate composed of a first member 301 that is a plate member on the punch 110 side and a second member 302 that is a plate member on the die 120 side. and the peripheral edge portion 120b of the die 120 and fixed. Then, the front end portion 111 of the punch 110 is driven from the first member 301 side by the above-described driving device, and the laminated body composed of the first member 301 and the second member 302 is formed by the front end surface 112 of the punch 110 and the top surface 123 of the die 120 . sandwiched between Thereby, the 1st member 301 and the 2nd member 302 are fastened by the mechanical clinch construction method.

FIG. 5 is an enlarged view of a portion surrounded by a thick dashed line in FIG. 4. In the first device 101 having the configuration described above, the first member 301 and the second member 302 are fastened by a mechanical clinch method. The process is divided into five situations from (a) to (e) and shown step by step. (a) shows the situation when the tip portion 111 of the punch 110 comes into contact with the first member 301 fixed between the punch holder 113 and the peripheral portion 120b of the die 120. FIG. Next, in (b), the tip portion 111 is further pushed toward the cavity 121 of the die 120 to bend the laminate composed of the first member 301 and the second member 302 , and as a result, the second member 302 is bent into the die 120 . comes into contact with the top surface 123 of the . Therefore, during the period from (a) to (b), the laminate composed of the first member 301 and the second member 302 is subjected to bending.

Next, (c) shows a state in which the tip portion 111 is further pushed in and a recess is being formed in the laminate composed of the first member 301 and the second member 302 . In addition to the bending process, the laminated body under this condition is subjected to a so-called "bulging process" in which the tip portion 111 is pressed to crush the laminated portion and cause plastic flow outward in the radial direction. Next, in (d), the tip portion 111 is further pushed in and the overhanging process further progresses, and the first member 301 enters the second member 302 to form an interlock portion, which is a portion where they are engaged with each other. represents the situation immediately before Finally, (e) represents the state in which the impacting of the tip portion 111 of the punch 110 is completed and the interlock portion is formed.

As described above, in the first device 101, the top surface 123 of the die 120 is formed as a concave surface, and the distance between the tip surface 112 of the punch 110 and the top surface 123 of the die 120 is the center of the top surface 123. It is configured to become smaller toward the outside in the radial direction from the top. As a result, plastic flow outward in the radial direction of the second member 302, which is a plate member on the die 120 side, is suppressed in the process of punching the punch 110 shown in FIGS. 5(a) to 5(d). Therefore, the amount of crushing of the second member 302 as the punch 110 is driven is also reduced. Correspondingly, the first member 301, which is a plate-like member on the punch 110 side, is crushed by the punch 110, and the radially outward plastic flow of the first member 301 is promoted.

As a result of the above, local stretching of the first member 301 on the side surface of the recess is suppressed, thereby reducing the problem of reduction in the thickness of the first member 301 and breakage of the first member 301 . Further, since the interlock amount is also increased, the fastening force between the first member 301 and the second member 302 is also increased.

<effect>
As described above, according to the first apparatus, while reducing defects such as reduction in thickness or cracks or cuts of the plate member on the side surface of the concave portion, a simple structure and/or control is not required. With this configuration, the fastening force between the plate-like members can be increased only by plastic deformation of the plate-like members without using other members such as rivets.

<Specific example of the top surface of the die provided in the first device>
As described above, in the first device, the top surface of the protrusion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip surface of the punch and the top surface of the die is the center of the top surface. The specific shape of the top surface of the die is not particularly limited, as long as it is configured such that it becomes smaller toward the outside in the radial direction from the top.

For example, as shown in (a) of FIG. 6, the top surface 123 of the convex portion 122 of the die provided in the first device may be formed as a concave curved surface. In this case, the top surface 123 may be formed as a concave spherical surface having a specific radius of curvature r2, as shown in FIG. 6(b). Alternatively, the top surface 123 of the convex portion 122 of the die provided in the first device may be formed as a concave conical surface having a specific cone angle θ2, as shown in FIG. 6(c). In this specification, the term "conical angle" means an angle formed by two generatrices in a cross section of a conical surface taken along a plane including an axis passing through the vertex of the conical surface.

<<Second embodiment>>
Various embodiments of the mechanical clinch device for plate-like members (hereinafter sometimes referred to as "second device") according to the second embodiment of the present invention will now be described.

At the tip portion 111 of the punch 110 illustrated in FIG. 1 described above, the tip surface 112 is formed as a spherical surface having a radius of curvature r1. However, as described above, as long as the distance between the tip end surface of the punch and the top surface of the die is configured to decrease radially outward from the center of the top surface, the shape of the tip end surface of the punch is not limited to this, and may be, for example, a curved surface other than a spherical surface, or may be a flat surface.

However, from the viewpoint of increasing the fastening force between the first member and the second member by reducing the thickness and/or breakage of the first member on the side surface of the recess or increasing the amount of interlock, it is difficult to drive the punch. It is more preferable to reduce the local stretching of the first member on the side surface of the recess by promoting plastic flow outward in the radial direction of the accompanying first member.

<Configuration of the second device>
Therefore, the second device is a mechanical clinch device for a plate-like member, which is the first device described above and in which the tip end surface of the punch is formed as a convex surface.

As described above, in the first device, the top surface of the protrusion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip surface of the punch and the top surface of the die is the center of the top surface. It is configured to become smaller toward the outside in the radial direction from the top. As a result, the outward plastic flow in the radial direction of the second member is suppressed, and the amount of crushing of the second member due to the impact of the punch is also reduced. Correspondingly, the amount of crushing of the first member increases with the impact of the punch, and the plastic flow of the first member to the outside in the radial direction is promoted. In addition to this, in the second device, since the tip end surface of the punch is formed as a convex surface, the radially outward plastic flow of the first member accompanying the driving of the punch is further promoted.

<effect>
As described above, according to the second device, the radially outward plastic flow of the first member accompanying the driving of the punch is further promoted. As a result, the local extension of the first member on the side surface of the recess is further reduced, the thinning and/or breakage of the first member on the side surface of the recess is further reduced, and the interlock amount is further increased. and the second member can be further increased in fastening force.

<Specific example of tip surface of punch provided in second device>
As described above, in the second device, the tip surface of the punch is formed as a convex surface. FIG. 7 is a schematic cross-sectional view showing a specific example of the shape of the tip surface of the punch provided in the second device, and is a schematic enlarged view of the tip portion 111 of the punch 110, similar to FIG. 1(b). is. The tip surface 112 of the punch 110 provided in the second device may be formed as a convex curved surface, for example, as shown in FIG. 7(a). In this case, the tip surface 112 may be formed as a convex spherical surface having a specific radius of curvature r1, as shown in FIG. 7(b). Alternatively, the tip surface 112 of the punch 110 provided in the second device may be formed as a concave conical surface having a specific cone angle θ1, as shown in FIG. 7(c). In this specification, the term "conical angle" means an angle formed by two generatrices in a cross section of a conical surface taken along a plane including an axis passing through the vertex of the conical surface.

Incidentally, as shown in FIG. 8A, when the tip surface 112 of the punch 110 is formed as a convex spherical surface and the top surface 123 of the die 120 is formed as a concave spherical surface, the tip surface 112 should be configured so that the curvature radius r1 of the top surface 123 is larger than the curvature radius r2 of the top surface 123. As a result, the above-mentioned requirement of the apparatus of the present invention that "the distance between the tip surface of the punch and the top surface of the die becomes smaller in the radial direction from the center of the top surface toward the outside" can be satisfied. effect can be achieved.

Further, as shown in FIG. 8B, when the tip surface 112 of the punch 110 is formed as a convex conical surface and the top surface 123 of the die 120 is formed as a concave conical surface, the tip The cone angle .theta.1 of surface 112 should be greater than the cone angle .theta.2 of top surface 123. FIG. As a result, the above-mentioned requirement of the apparatus of the present invention that "the distance between the tip surface of the punch and the top surface of the die becomes smaller in the radial direction from the center of the top surface toward the outside" can be satisfied. effect can be achieved.

By the way, when the tip end face of the punch is formed as a convex face as described above, the processing of the tip end face becomes complicated compared to the case where the tip end face of the punch is formed as a flat face, which may lead to an increase in manufacturing cost. Therefore, the top surface of the convex portion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip end surface of the punch and the top surface of the die becomes smaller toward the outside in the radial direction from the center of the top surface. If a sufficient effect is achieved by being configured so as to achieve a sufficient effect, the tip surface of the punch may be formed as a flat surface.

The effects of the present invention in reducing defects such as cracks or cuts and reducing the thickness of the plate member on the side surface of the recess in the mechanical clinch method and increasing the amount of interlock are confirmed. Specifically, using the mechanical clinch device according to the present invention and the mechanical clinch device according to the prior art, two metal plates made of different materials were fastened together, and cross-sections of the respective interlock portions were observed.

<Configuration of mechanical clinch device>
1 to 5, FIG. 6(b), FIG. 7(b), and As shown in FIG. 8(a), the tip surface of the punch is formed as a convex spherical surface and the top surface of the die is formed as a concave spherical surface. In the apparatus of the embodiment, the radius of curvature r1 of the tip end surface of the punch is 11 mm, and the radius of curvature r2 of the top surface of the die is 9 mm. As a result, the distance between the tip surface of the punch and the top surface of the die becomes smaller as it goes radially outward from the center of the top surface.

On the other hand, in a mechanical clinch device according to a comparative example of the prior art (hereinafter sometimes referred to as a “comparative device”), as shown in FIGS. The faces are formed as planes parallel to each other. That is, in the comparative example, the distance between the tip surface of the punch and the top surface of the die is constant at any position on the top surface.

<First member and second member>
A high-strength steel plate having a thickness of 1.0 mm and a tensile strength of 590 MPa was adopted as the first member, which is a plate-shaped member arranged on the punch side. On the other hand, as the second member, which is a plate-like member arranged on the die side, a plate material of aluminum alloy (A6061-T6) having a thickness of 2.0 mm was used.

As described above, the second member (aluminum alloy plate) is softer and thicker than the first member (high-tensile steel plate), so the second member is easier to punch than the first member. associated plastic flow is likely to occur. Therefore, the combination of the plate-like members described above corresponds to a combination in which defects such as reduction in the thickness of the plate-like members or cracks or cuts on the side surfaces of the concave portion as described above become more conspicuous.

<Fastening of the first member and the second member by the mechanical clinch method>
Using the above-described embodiment device and comparative example device, the above-described first member and second member were fastened by a mechanical clinch construction method. It is considered that the fastening process proceeded in the embodiment device as described with reference to FIG. 5, and the fastening process proceeded in the comparative example device as described with reference to FIG.

<Cross-sectional observation of the fastening portion between the first member and the second member>
The fastening portion (recessed portion formed by punching and its peripheral portion) between the first member (high-tensile steel plate) and the second member (aluminum alloy plate) formed as described above is commonly used for punches and dies. A micrograph of the cross section was taken by cutting along a plane containing the axis AX. FIG. 9 is a schematic cross-sectional view showing the fastening portion between the first member and the second member formed by the apparatus of the example, and FIG. It is a typical sectional view showing a fastening portion.

Regarding the combination of the first member and the second member described above, no breakage of the first member was observed on the side surface of the concave portion at the fastening portion by either the example device or the comparative example device, and the interlock portion was formed. (See area bounded by thick dashed line). However, as is clear from the comparison between FIG. 9 and FIG. 10, regarding the thickness T of the first member on the side surface of the recess and the amount of interlock L, the fastening portion according to the device of the example is better than that of the device of the comparative example. It was confirmed to be larger than the fastening portion.

This is because the top surface of the protrusion formed on the bottom surface of the die is formed as a concave surface, and the distance between the tip surface of the punch and the top surface of the die increases radially outward from the center of the top surface. This is considered to be due to the fact that the embodiment device is configured to be small. Furthermore, in the embodiment apparatus, the tip surface of the punch is formed as a convex spherical surface, and the top surface of the die is formed as a concave spherical surface. As a result, the plastic flow of the first member to the outside in the radial direction due to the impact of the punch is further promoted, so that the local extension of the first member on the side surface of the recess is further reduced. It is believed that the thinning was further reduced and the amount of interlock was further increased.

<effect>
As described above, according to the embodiment device of the present invention, compared to the conventional comparative example device, the thinning of the first member on the side surface of the recess can be reduced and the interlock amount can be increased. , the fastening force between the first member and the second member can be further increased. That is, according to the present invention, the thickness of the plate-shaped member on the side surface of the recess is reduced, and defects such as cracks and cuts are reduced, and a rivet can be formed by a simple configuration without requiring a complicated configuration and/or control. It is possible to increase the fastening force between the plate-like members only by plastic deformation of the plate-like members without using other members such as.

<Overview>
In Example 2, the same mechanical clinch device as in Example 1 (i.e., Example device and Comparative Example device) was used to fasten two metal plates made of different materials, and each interlock portion Observed the cross section of However, in Example 2, an ultra-high-tensile steel plate having a thickness of 1.0 mm and a tensile strength of 1180 MPa was used as the first member, which is a plate-shaped member arranged on the punch side. On the other hand, as the second member, which is a plate-like member arranged on the die side, a plate material of aluminum alloy (A6061-T6) having a thickness of 2.0 mm similar to that of Example 1 was adopted.

As described above, in Example 2, the first member (ultra-high-tensile steel plate) harder than the first member (high-tensile steel plate) in Example 1 was employed. Therefore, compared to Example 1, there is a greater difference between the first member and the second member in the likelihood of plastic flow occurring due to the impact of the punch. Therefore, in Example 2, compared with Example 1, it is expected that the difference between the present invention and the prior art will be expressed more clearly.

<Cross-sectional observation of the fastening portion between the first member and the second member>
The joint portion between the first member (ultra-high-tensile steel plate) and the second member (aluminum alloy plate) formed by the same joint process as in Example 1 is cut along a plane including the common axis AX of the punch and die. Then, micrographs of the cross section were taken. FIG. 11 is a schematic cross-sectional view showing the fastening portion between the first member and the second member formed by the apparatus of the example, and FIG. It is a typical sectional view showing a fastening portion.

As shown in FIG. 11, in the fastening portion by the example device, the thickness T and the interlock amount L of the first member on the side surface of the recess are greater than in Example 1 in which the ultra-high-strength steel plate is used as the first member. small. However, in the fastening portion according to the embodiment device, the interlock portion is formed without causing the breakage of the first member on the side surface of the recess (see the area surrounded by the thick dashed line), and the first member and the second member are connected. well concluded. On the other hand, as shown in FIG. 12, the first member fractured on the side surface of the concave portion at the fastening portion according to the comparative example device. When such breakage occurs, the fastening force between the first member and the second member is reduced.

<effect>
As described above, even when there is a large difference between the first member and the second member in the likelihood of plastic flow occurring due to the impact of the punch, according to the embodiment device of the present invention, the first Since thinning and breakage of the member can be reduced and the amount of interlock can be increased, the fastening force between the first member and the second member can be further increased. That is, according to the present invention, the thickness of the plate-shaped member on the side surface of the recess is reduced, and defects such as cracks and cuts are reduced, and a rivet can be formed by a simple configuration without requiring a complicated configuration and/or control. It is possible to increase the fastening force between the plate-like members only by plastic deformation of the plate-like members without using other members such as.

Although several embodiments and examples having specific configurations have been described above for the purpose of illustrating the present invention, sometimes with reference to the accompanying drawings, the scope of the present invention is not limited to these exemplary embodiments. It should not be construed as being limited to the embodiments and examples, and it goes without saying that modifications can be made as appropriate within the scope of the claims and the matters described in the specification.

DESCRIPTION OF SYMBOLS 101... Mechanical clinch apparatus (this invention), 110... Punch (this invention), 111... Tip part (this invention), 112... Tip surface (this invention), 113... Punch holder (this invention), 120... Die (this invention) Invention), 120a Central portion (present invention), 120b Peripheral edge portion (present invention), 121 Cavity (present invention), 122 Convex portion (present invention), 123 Top surface (present invention), 201 Mechanical Clinch device (prior art) 210 Punch (prior art) 211 Tip (prior art) 212 Tip face (prior art) 213 Punch holder (prior art) 220 Die (prior art) 220a... Central part (prior art) 220b... Peripheral part (prior art) 221... Cavity (prior art) 222... Convex part (prior art) 223... Top surface (prior art) 301... First member 302: second member, AX: axis, r1: radius of curvature (tip surface), r2: radius of curvature (top surface), θ1: cone angle (tip surface), and θ2: cone angle (top surface).

Claims (12)

Equipped with punches and dies that face each other so that they can approach and move away from each other,
A tip surface facing the die is formed at the tip of the punch,
A cavity opening toward the punch is formed at the tip of the die,
A convex portion protruding from the bottom surface of the cavity toward the punch is formed inside the cavity,
A top surface, which is a surface facing the tip surface, is formed at the tip portion of the convex portion,
The plurality of plate-shaped members are fastened together by punching the punch into the laminated portion where the plurality of plate-shaped members overlap and sandwiching the laminated portion between the tip surface and the top surface. , a mechanical clinch device for a plate-like member,
the top surface is formed as a concave surface,
The distance between the tip surface and the top surface is configured to decrease radially outward from the center of the top surface.
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 1,
The top surface is formed as a concave curved surface,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 2,
wherein the top surface is formed as a concave spherical surface;
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 1,
the top surface is formed as a concave conical surface;
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to any one of claims 1 to 4,
The tip surface is formed as a convex surface,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 5,
The tip surface is formed as a convex curved surface,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 6,
The tip surface is formed as a convex spherical surface,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 5,
The tip surface is formed as a convex conical surface,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to any one of claims 1 to 4,
The tip surface is formed as a plane,
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 3,
The tip surface is formed as a convex spherical surface,
the radius of curvature r1 of the tip surface is greater than the radius of curvature r2 of the top surface;
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to claim 4,
The tip surface is formed as a convex conical surface,
the cone angle θ1 of the tip surface is greater than the cone angle θ2 of the top surface;
Mechanical clinch device for plate-like members. A mechanical clinch device for a plate member according to any one of claims 1 to 11,
the protrusion is formed as a truncated cone having a concave top surface;
Mechanical clinch device for plate-like members.

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