Method for manufacturing a caulked assembly

Provided is a method for manufacturing a caulked assembly that is capable of manufacturing the caulked assembly at a low cost, preventing reduction of the strength of a columnar body caused by a circumferential groove, preventing deformation of the columnar body, and assembling a slimmer columnar body with a plate-like body. A mounting hole 10 for inserting and assembling a columnar body 2 is provided in a metallic plate-like body 1, and a thick portion 11 is formed along an inner circumferential edge of the mounting hole 10. Thereafter, as shown in FIG. 1(a), the columnar body 2 is inserted into the mounting hole 10 of the plate-like body 1 so that the plate-like body 1 is set in an assembly position on an outer circumferential surface of the columnar body 2. Further, the thick portion 11 is compressively pressed from an axial direction of the columnar body so as to be plastically deformed toward the center of the mounting hole 10 to thereby tighten and fix the thick portion 11 to the outer circumferential surface of the columnar body 2.

TECHNICAL FIELD

The present invention relates to a high-strength processing technique that is capable of firmly fixing a hollow or solid columnar body to a plate-like body.

BACKGROUND ART

Conventionally, a processing technique of this kind has been performed in the following manner as in Patent Document 1. A flange portion is formed on a midway part of a shaft body as shaft caulking, and a circular hole is punched on a plate-like body which is a press component as a subject of assembly. A tip of the shaft body which is inserted through the circular hole is crushed by a caulking machine for exclusive use so that the press component is sandwiched between the crushed head part of the shaft body and the flange portion to thereby assemble the shaft body with the plate-like body. Alternatively, a more complicated special shape is previously formed on the shaft body, and the shaft body is press-fitted into the circular hole formed in the press component to thereby join the shaft body to the press component.

However, a large flange portion needs to be provided on the midway part of the shaft body in order to sandwich the press component between the crushed head part of the shaft body and the flange portion. Accordingly, it is necessary to cut a shaft material that is approximately 50% thicker than a shaft diameter required for using as a product to produce a flange shape, which increases material and processing costs. Further, a high manufacturing cost is required also for forming the special shape, which limits the cost reduction.

In view of the above, there has also been proposed a caulking method in which a mounting hole for inserting and assembling a columnar body is provided in a metallic plate-like body, a thick portion is formed along an inner circumferential edge of the mounting hole by burring, a circumferential groove having a predetermined depth is formed at an assembly position on an outer circumferential surface of the columnar body to be inserted into the mounting hole, the columnar body is inserted into the mounting hole of the metallic plate-like body so as to be set in an assembly position where the thick portion and the circumferential groove face each other, and the thick portion is compressively pressed from an axial direction of the columnar body so as to be plastically deformed toward the center of the mounting hole to thereby cause the thick portion to bite into the facing circumferential groove of the columnar body (see Patent Document 2 and Patent Document 3).

In this method, it is not necessary to provide a flange portion on the midway part of the columnar body or produce a complicated special shape. Therefore, this method makes it possible to assemble the plate-like body with the columnar body by calking by easy press working as well as at a low cost only by providing the circumferential groove which can be easily formed in the columnar body and providing the thick portion on the periphery of the mounting hole of the plate-like body by burring. Further, since the thick portion is formed on the plate-like body, and then plastically deformed so as to bite into the circumferential groove, it is possible to obtain sufficient caulking strength as well as the strength of the plate-like body itself. Therefore, it is possible to achieve an effect that, even if the plate-like body is thinner than a conventional plate-like body, the same high caulking strength as that of the conventional one can be obtained.

CITATION LIST

Patent Literatures

SUMMARY OF INVENTION

Technical Problem

In the meantime, when the thick portion formed by burring and the like is crushed to caulk the plate-like body with the columnar body, a rough standard of the smallest size of a remaining convex portion of the thick portion of the plate-like body after the caulking is zero (shaft holding size plate thickness). However, if there is no straight remaining part across the circumferential groove other than the part biting into the circumferential groove, the accuracy in the perpendicularity and the like of the caulked columnar body cannot be ensured. Therefore, a limit of the plate thickness of the plate-like body depends on the width of the circumferential groove of the columnar body. For this reason, such a method is unsuitable for caulking of a thin plate.

In addition, since it is necessary to form the circumferential groove on the columnar body, a cost for the processing thereof is required. Further, stress concentration occurs in the circumferential groove, which may cause bend of such a part depending on handling thereof. Accordingly, the shaft diameter of the columnar body is limited, and the method is therefore unsuitable for caulking of a slim shaft. Further, when a circumferential groove is formed on the columnar body in this manner, directivity may be generated in the shaft, which may lead to an operational error. In order to solve such a problem, another circumferential groove can be added in a position that is symmetrical to the position where the circumferential groove is previously formed to thereby cancel the directivity. However, in this case, an additional cost is required. Further, even in the case of a relatively thick columnar body, when the columnar body is made partially or totally hollow, for example, by forming a screw hole in the axial direction thereof, and a circumferential groove is formed within the hollow area or in the vicinity thereof, there is a problem in that the wall thickness of the columnar body in such an area is made thin and an enough strength cannot, therefore, be obtained. Especially in the case of a columnar body that is made of a low-strength material such as resin and aluminum, strength poverty caused by forming a circumferential groove within a hollow area or in the vicinity thereof becomes pronounced. Such a problem arises also when forming a circumferential groove in a columnar body that is hollow from the beginning. Further, even in the case of a columnar body that is not hollow, when the columnar body is made of a low-strength material such as resin and aluminum, and a plate-like body is made of, for example, a material that is hard relative to the material of the columnar body such as iron materials and stainless steel materials, even if caulking is tried to be performed by forming a circumferential groove, the plate-like body cannot bite into the circumferential groove properly. As a result, caulking strength that should be obtained by the plate-like body biting into the circumferential groove cannot be obtained. Instead, stress is generated in the circumferential groove due to the plate-like body biting thereinto, or stress concentration is generated in the circumferential groove due to drop impact or the like of a product, which may cause a problem such as deformation and breakage of the product.

Further, although the burring of the thick portion is performed after a prepared hole is punched on the plate-like body, it is not possible to perform caulking on a shaft having a smaller diameter than the diameter of the prepared hole in a caulking method in which the thus formed thick portion is crushed. That is, when burring is performed on a plate member, blanking is first performed to form a so-called prepared hole, and a processing for forming a convex is then performed. A diameter for holding a caulked shaft, namely, the diameter of the mounting hole after crushing a thick portion which is composed of the convex formed by burring so that the thickness of the thick portion becomes the same as the thickness of the plate member, namely, a remaining convex becomes zero, never becomes smaller than the diameter of the prepared hole before the burring. That is, a shaft having a smaller diameter than the diameter of the prepared hole cannot be caulked. Further, it is generally recognized that a limit of the diameter of a prepared hole which is formed in a metallic thin plate having a thickness of equal to or less than 1 mm is approximately 0.6 mm on a mass-produced level. If the diameter of a prepared hole is made smaller than this value, a trouble such as punch break off may occur, thereby lowering the productivity. Therefore, it is not possible to assemble a shaft having a diameter equal to or smaller than 0.6 mm with such a thin plate by caulking.

As another method, there has been also proposed a method in which a washer member is provided on a lower surface of a plate-like body, the washer member is caulked so as to fill a circumferential groove formed in a pin, and the pin is held by sandwiching the plate-like body between a flange of the pin and the washer member (see Patent Document 4). However, in this method, a flange is required, a caulked assembly obtained after the caulking is made thick due to the thickness of the flange and a remaining part of the washer caused by insufficient caulking, and there is a problem also in the accuracy thereof.

Further, it is common to perform nitriding on a thin plate-like body in order to increase the strength thereof. However, the above-described caulking by burring is rigid and has low ductility, and cannot therefore be plastically deformed. Therefore, the nitriding cannot be performed due to generation of cracking and the like. Therefore, in the case of a grinding shaft that is particularly slim and has been hardened, there has been performed a method in which a columnar body2is previously press-fitted into a bush103, and the bush103is then caulked with a plate-like body1as shown inFIGS. 44(a) and 44(b). However, this method needs to perform both of a press-fitting step of the bush103and a caulking step, thereby limiting improvement of the manufacturing efficiency as well as increasing cost. Further, since the caulking is performed with the bush103into which the columnar body2being press-fitted, when mechanical shock and stress caused by the caulking are applied to the bush103, a problem such as reduction of press-fitting maintaining force is caused. Further, since the accuracy in perpendicularity and the like depends on the accuracy of components, the accuracy of perpendicularity and the like is also deteriorated due to the influence of variation of the components and the like.

Solution to Problem

In order to solve the above problems, the present invention provides a method for manufacturing a caulked assembly of a metallic plate-like body with a hollow or solid columnar body, the method comprising the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body and forming a thick portion along an inner circumferential edge of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the thick portion from an axial direction of the columnar body to plastically deform the thick portion toward a center of the mounting hole to tighten and fix the thick portion to the outer circumferential surface of the columnar body.

It is preferred that the columnar body be formed into a straight shape which does not have a flange portion to be locked with an upper surface or a lower surface of a circumferential edge of the mounting hole of the metallic plate-like body in an end part and a midway part in an axial direction of the columnar body.

Further, the present invention also provides a method for manufacturing a caulked assembly of a metallic plate-like body with a hollow or solid columnar body, the method comprising the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body and forming a step portion around the mounting hole along a whole circumference or a part of the circumference of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the step portion from an axial direction of the columnar body to plastically deform the step portion toward a center of the mounting hole to tighten and fix an inner circumferential part of the mounting hole to the outer circumferential surface of the columnar body.

It is preferred that a depressed surface of the step portion at one side thereof be made to serve as a receiving portion, and the step portion be deformed by applying pressure to a protruding surface of the step portion at the other side thereof.

In addition, it is preferred that the step portion be compressively pressed while positioning and holding the columnar body located at an inner side of the step portion by a press tool which supports the receiving portion of the step portion.

Further, it is preferred that the step portion be formed by half blanking of press working.

Further, it is also preferred that the step portion be formed in a region separated from an inner circumferential edge of the mounting hole.

Further, it is also preferred that a thick portion be formed along the inner circumferential edge of the mounting hole, and the step portion and the thick portion be compressively pressed.

In addition, it is also preferred that the method further comprise a step of forming a concave portion having a predetermined depth in the assembly position on the outer circumferential surface of the columnar body to be inserted into the mounting hole, and the caulking step be performed by compressively pressing the step portion from the axial direction to plastically deform the step portion toward the center of the mounting hole to tighten and fix the inner circumferential part of the mounting hole to the outer circumferential surface of the columnar body and cause the inner circumferential part of the mounting hole to bite into the concave portion.

Further, the present invention also provides a method for manufacturing a caulked assembly of a metallic plate-like body with a hollow or solid columnar body, the method comprising the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body by performing burring on the metallic plate-like body without a prepared hole and forming a cylindrical thick portion by the burring along an inner circumferential edge of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the thick portion from an axial direction of the columnar body to plastically deform the thick portion toward a center of the mounting hole to tighten and fix the thick portion to the outer circumferential surface of the columnar body.

It is preferred that the thick portion formed by the burring be formed into a circular truncated cone shape which is tapered toward a tip thereof, and the tip having a small diameter of the thick portion formed along the mounting hole be made capable of inserting the columnar body therethrough.

Further, it is also preferred that the method further comprise a step of forming a concave portion having a predetermined depth in the assembly position on the outer circumferential surface of the columnar body to be inserted into the mounting hole, and the caulking step be performed by compressively pressing the thick portion from the axial direction to plastically deform the thick portion toward the center of the mounting hole to tighten and fix the thick portion to the outer circumferential surface of the columnar body and cause the thick portion to bite into the concave portion.

Further, the present invention also provides a method for manufacturing a caulked assembly of a plate-like body with a hollow or solid columnar body, the method comprising the steps of providing, in the plate-like body, a fitting hole for fitting a holding member having a mounting hole for inserting the columnar body; fitting the holding member into the fitting hole; inserting the columnar body into the mounting hole of the holding member to set the plate-like body and the holding member in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the holding member from an axial direction of the columnar body to plastically deform the holding member both inwardly and outwardly, namely, toward a center of the mounting hole and also toward an inner circumferential surface of the fitting hole of the plate-like body to tighten and fix the holding member to the outer circumferential surface of the columnar body and cause the holding member to spread within an inner circumferential part of the fitting hole of the plate-like body so as to be fixed thereto.

It is preferred that the holding member be fixed to the inner circumferential part of the fitting hole of the plate-like body by fixing the holding member to the inner circumferential surface of the fitting hole by spread of the holding member, and also by plastically deforming the holding member so as to cover a part of a surface of the plate-like body around the fitting hole to fix the holding member to the surface.

Further, it is also preferred that a depression be formed on the inner circumferential surface of the fitting hole, and the holding member be fixed to the inner circumferential part of the fitting hole of the plate-like body by fixing the holding member to the inner circumferential surface of the fitting hole by spread of the holding member, and also by causing the holding member to bite into the depression.

Further, it is also preferred that the method further comprise a step of forming a concave portion having a predetermined depth in the assembly position on the outer circumferential surface of the columnar body to be inserted into the mounting hole of the holding member, and the caulking step be performed by compressively pressing the holding member from the axial direction to plastically deform the holding member both inwardly and outwardly, namely, toward the center of the mounting hole and also toward the inner circumferential surface of the fitting hole of the plate-like body to tighten and fix the holding member to the outer circumferential surface of the columnar body as well as cause the holding member to bite into the concave portion, and cause the holding member to spread within the inner circumferential part of the fitting hole of the plate-like body so as to be fixed thereto.

Advantageous Effects of Invention

The method for manufacturing the caulked assembly according to an aspect of the present invention as described above includes the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body and forming a thick portion along an inner circumferential edge of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the thick portion from an axial direction of the columnar body to plastically deform the thick portion toward a center of the mounting hole to tighten and fix the thick portion to the outer circumferential surface of the columnar body. Therefore, it is not necessary to provide a conventional circumferential groove. Accordingly, since grooving is not required, it is possible to manufacture the caulked assembly at a low cost, prevent reduction of the strength (concentration of stress) of the columnar body caused by a circumferential groove, prevent deformation of the columnar body, and assemble a slimmer columnar body with the plate-like body.

Generally, press-fitting between metals each having a particularly high hardness such as iron metal and stainless steel metal is difficult. However, it is possible to easily obtain a configuration equivalent thereto by the method of the present invention. Further, since it is not necessary to cause a plate-like body to bite into a circumferential groove, it is possible to firmly fixing even a thin plate-like body whose thick portion would have a small volume to a columnar body with sufficient strength by caulking. Further, if there is no straight remaining part across a circumferential groove other than a part of a columnar body, the part biting into the circumferential groove, it is not possible to ensure the accuracy in the perpendicularity and the like of the caulked columnar body. However, in the method of the present invention, since a circumferential groove is not provided, it is possible to assemble a plate-like body that is made thin to the limit of holding accuracy with a columnar body. In addition, also regarding a columnar body, it is possible to assemble a columnar body that is made slim to the limit of hole processing of a plate-like body with the plate-like body. Furthermore, since a circumferential groove is not required to be provided in a columnar body, it is possible to cancel directivity of a columnar body before assembling. Therefore, a mistake of an assembling direction can be prevented. In addition, control for producing a circumferential groove is not necessary as well as an operation is made easier, thereby making it possible to achieve a high manufacturing efficiency. Furthermore, it is possible to fix a plate-like body even to a columnar body that is partially or totally hollow by caulking not with insufficient strength, but with sufficient strength. Furthermore, even in a case where a columnar body is made of a low-strength material such as resin and aluminum, and a plate-like body is made of a material that is hard relative to the material of the columnar body such as iron materials and stainless steel materials, it is also possible to fix the plate-like body to the columnar body by caulking with sufficient strength. In this case, there is no risk of deformation or breakage of the columnar body due to insufficient strength.

Further, according to another aspect of the present invention, the method includes the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body and forming a step portion around the mounting hole along a whole circumference or a part of the circumference of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the step portion from an axial direction of the columnar body to plastically deform the step portion toward a center of the mounting hole to tighten and fix an inner circumferential part of the mounting hole to the outer circumferential surface of the columnar body. Also in this case, formation of a circumferential groove is not necessarily required, and the plate-like body and the columnar body can be firmly fixed to each other by caulking. Further, even in a case where a circumferential groove is omitted, the same effect as above can be achieved. In addition, a columnar body that is slimmer than the mounting hole can be assembled with the plate-like body, and a columnar body having an outer size equal to or smaller than the limit of the diameter of a pressed hole (0.6 mm, for example) can also be fixed to the plate-like body by caulking.

Further, since a depressed surface of the step portion at one side thereof is made to serve as a receiving portion, and the step portion is deformed by applying pressure to a protruding surface of the step portion at the other side thereof, it is possible to position and reliably hold the plate-like body by the receiving portion. Therefore, it is possible to assemble a columnar body that is slimmer than the mounting hole with the plate-like body accurately and reliably. Specifically, by compressively pressing the step portion while positioning and holding the columnar body located at an inner side of the step portion by a press tool which supports the receiving portion of the step portion, such a positioning can be ensured, and even a slim columnar body can therefore be accurately assembled with a plate-like body. Further, the step portion can be efficiently produced by half blanking of press working.

Further, according to yet another aspect of the present invention, the method includes the steps of providing, in the metallic plate-like body, a mounting hole for inserting and assembling the columnar body by performing burring on the metallic plate-like body without a prepared hole and forming a cylindrical thick portion by the burring along an inner circumferential edge of the mounting hole; inserting the columnar body into the mounting hole of the metallic plate-like body to set the metallic plate-like body in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the thick portion from an axial direction of the columnar body to plastically deform the thick portion toward a center of the mounting hole to tighten and fix the thick portion to the outer circumferential surface of the columnar body. Since there is no prepared hole, an effective filling volume can be obtained to the maximum extent possible. Accordingly, a columnar body that is made slim to the limit of obtaining a necessary filling volume can be fixed to the plate-like body by caulking. Further, since there is no prepared hole, a tip of a convex portion of the thick portion formed by burring has more irregularities than a case where a prepared hole is previously formed on the plate-like body, and the tip therefore becomes non-uniform and rough. However, such non-uniformity is made uniform by pressure applied thereto by caulking, and does not therefore cause an adverse effect on the fixing by caulking and the appearance of the caulked assembly.

Further, the thick portion formed by the burring is formed into a circular truncated cone shape which is tapered toward a tip thereof, and the tip having a small diameter of the thick portion formed along the mounting hole is made capable of inserting the columnar body therethrough. Therefore, an expansion amount of the tip of the thick portion formed by the burring is reduced, thereby reducing the above-described non-uniformity of the tip of the convex portion of the thick portion.

Further, according to yet another aspect of the present invention, the method includes the steps of providing, in the plate-like body, a fitting hole for fitting a holding member having a mounting hole for inserting the columnar body; fitting the holding member into the fitting hole; inserting the columnar body into the mounting hole of the holding member to set the plate-like body and the holding member in an assembly position on an outer circumferential surface of the columnar body; and caulking for compressively pressing the holding member from an axial direction of the columnar body to plastically deform the holding member both inwardly and outwardly, namely, toward a center of the mounting hole and also toward an inner circumferential surface of the fitting hole of the plate-like body to tighten and fix the holding member to the outer circumferential surface of the columnar body and cause the holding member to spread within an inner circumferential part of the fitting hole of the plate-like body so as to be fixed thereto. Therefore, it is possible to assemble the plate-like body with the columnar body without sandwiching the plate-like body between a flange of a pin and a washer. Therefore, the caulked assembly can be made thin. Further, since it is not necessary to perform press-fitting as shown inFIGS. 44(a) and 44(b), and the caulking can therefore be performed by a single step, the assembly can be performed with high working efficiency as well as at a low cost. In addition, since the holding member is arranged around the straight columnar body as well as within the range of the plate thickness of the plate-like body, and then pressed, a thin caulked assembly with high accuracy can be obtained. Furthermore, since the assembly is performed by forming the mounting hole not in the plate-like body, but in the holding member, even a mounting hole having a diameter equal to or less than 0.5 mm can be easily processed by cutting work. Therefore, it is also possible to assemble a further slimmer columnar body with a plate-like body.

DESCRIPTION OF EMBODIMENTS

First, the first embodiment of the present invention will be described with reference toFIG. 1(a)toFIG. 8(c).

In the present invention, a caulked assembly A of a metallic plate-like body1with a hollow or solid columnar body2is manufactured. In the present embodiment, as shown inFIGS. 1(a) to 1(c), a mounting hole10for inserting and assembling the columnar body2is provided in the metallic plate-like body1, and a thick portion11is formed along an inner circumferential edge of the mounting hole10. Thereafter, as shown inFIG. 1(a), the columnar body2is inserted into the mounting hole10of the plate-like body1so that the plate-like body1is set in an assembly position on an outer circumferential surface of the columnar body2. Further, as shown inFIGS. 1(b) and 1(c), the thick portion11is compressively pressed from an axial direction of the columnar body2so as to be plastically deformed toward a center of the mounting hole10to thereby tighten and fix the thick portion11to the outer circumferential surface of the columnar body2.

As just described, the present embodiment does not have a conventional structure in which a circumferential groove is formed on a columnar body, and a thick portion of a plate-like body is caused to bite into the circumferential groove, but has a structure in which the thick portion11is fixed to the outer circumferential surface of the columnar body2by pressure. Therefore, grooving for forming a circumferential groove is not required and the caulked assembly can therefore be manufactured at a low cost. In addition, reduction of the strength of the columnar body2can be prevented, which makes it possible to assemble the columnar body2which is slimmer than a conventional columnar body with the plate-like body1. The caulked assembly A is suitable for electronic components or the like. However, the caulked assembly A can, of course, be applied to other various components and products. For example, the caulked assembly A can be utilized in various forms such as a form of an assembly of a support plate on which components such as a circuit and a fan motor are placed with a strut member in the internal structure of a product, and a form of an assembly of components themselves such as a plurality of cylindrical bodies with a base plate when a heat sink is constructed by assembling the columnar bodies with the base plate.

The columnar body2has a straight shape which does not have a flange portion to be locked with an upper surface or a lower surface of a circumferential edge of the mounting hole10of the plate-like body1in an end part and a midway part in the axial direction thereof. The columnar body2may also have another shape as long as it does not have a flange portion for locking. That is, as long as a region of the columnar body2, the region being assembled to the plate-like body1, has a straight shape having neither a circumferential groove nor a flange, the columnar body2may have a groove, a flange, a structure having a shape other than a shaft-like shape and the like in the other region thereof. Further, the columnar body2may be solid, or may also be a cylindrical body which is made by forming a thin plate into a cylindrical shape such as a frame of a motor vehicle and a pillar. As a material of the columnar body2, various materials such as a synthetic resin, ceramics, wood, composite fiber can also be employed other than metal.

The mounting hole10for inserting and assembling the columnar body2is provided in the plate-like body1. The thick portion11is formed along the inner circumferential edge of the mounting hole10. Although, in the following description, the edge of the mounting hole10is raised into a cylindrical shape in a single direction by burring to thereby form the thick portion11, the thick portion11may be formed by another processing. The plate-like body1has to include at least the mounting hole10which is formed in a plate-like part thereof and the thick portion11of the mounting hole10, and may therefore include a structure having a shape other than a plate-like shape in the other part thereof.

Although, in the present embodiment, the mounting hole10of the plate-like body1on which the thick portion11is formed into a circular shape, and the columnar body2is a shaft body which is inserted and fitted into the mounting hole10and therefore includes the outer circumferential surface having a circular cross-sectional shape, the present invention is not limited to such a shape. For example, the plate-like body1can be assembled also with the columnar body2that has an irregular, arc, or square cross-sectional shape by forming the mounting hole10that has a shape corresponding to the shape of the columnar body2. Further, the shapes of the plate-like body1and the columnar body2may not be the same as each other. For example, it is also preferred that the columnar body2have a polygonal cross-sectional shape and the mounting hole10have a circular shape which makes external contact therewith, the columnar body2have a circular cross-sectional shape and the mounting hole10have a polygonal shape which makes external contact therewith, and the like.

In the plate-like body1of the present embodiment, a thick portion is not caused to bite into a circumferential groove of a columnar body as in a conventional method. Therefore, even when the thin plate-like body1is thin and the thick portion11therefore has a small volume, the plate-like body1can be firmly fixed to the columnar body2by caulking with high strength, and the plate-like body1that is made thin to the limit of the holding accuracy can be assembled with the columnar body2. Also, the columnar body2that is made slim to the limit of the hole processing of the mounting hole10of the plate-like body1can be assembled with the plate-like body1.

Such caulking can be performed using a press apparatus4as shown inFIGS. 1(a) to 1(c). In the present embodiment, the press apparatus4is composed of a lower receiving tool40which includes a fitting hole40ainto which the columnar body2is fitted and supports a lower surface of the plate-like body1from which the thick portion11does not protrude, an upper receiving tool41which is arranged on an upper surface of the plate-like body1and includes a fitting hole41adefined by an inner circumferential surface thereof which comes into contact with an outer circumferential surface of the thick portion11and an outer circumferential surface of a press tool42which presses the thick portion11, the press tool42which includes an insertion hole42athrough which the columnar body2is inserted and is slidingly guided in a vertical axis direction along the inner circumferential surface of the fitting hole41aof the upper receiving tool41to thereby apply pressure on the thick portion11in the axial direction from top to down, and a pressure applying tool43which applies pressure on the thick portion11by moving the press tool42downward.

By operating the pressure applying tool43to thereby move the press tool42downward, as shown inFIGS. 1(a) to 1(c), the press tool42presses the thick portion11downward. Accordingly, the thick portion11whose position is restricted by an upper surface of the lower receiving tool40and the inner circumferential surface of the fitting hole41aof the upper receiving tool41is plastically deformed toward the center of the mounting hole10and thereby fixed to the outer circumferential surface of the columnar body2by pressure. As a result, the caulked assembly A (FIG. 1(c)) in which the plate-like body1and the columnar body2are firmly integrated with each other can be obtained.

The press apparatus4is not limited to the above structure as long as it can compressively press the thick portion11from the axial direction to thereby plastically deform the thick portion11toward the center of the mounting hole10so that the thick portion11is fixed to the outer circumferential surface of the columnar body2by pressure. For example, although pressure is applied to the press tool42by the pressure applying tool43and the applied pressure is received by the lower receiving tool40in the present embodiment, pressure may also be applied to the lower receiving tool40by a pressure applying tool. The columnar body2is biased downward by a spring so as to prevent uplift thereof.

Further, as shown inFIGS. 1(a) and 3(a), a bent corner11aon the inner circumference of the mounting hole10is formed into an R shape due to shear drop at the time of burring, and a space between the corner11aand the apparatus serves as a caulking strength adjustable range in the present embodiment. That is, the strength adjustable range can be determined as a range from the start of filling of the space by deformation of the thick portion11until the completion of the filling. The space may be a tiny space. Further, the corner11amay have a shape other than an R shape. For example, as shown inFIG. 3(b), it is also preferred to form the corner11ainto a C-surface shape by sheet metal processing to thereby form a space in the same manner as above. Further, it is also preferred to combine an R shape with a C-surface shape so that the adjustable range is made broader.

Further, even when the corner11ais not formed into the above R shape or C-surface shape as shown inFIG. 3(c), by setting a space between the outer circumferential surface11bof the thick portion11and the inner circumferential surface of the fitting hole41aof the upper receiving tool41of the press apparatus4as shown inFIG. 2(a), for example, the thus set space can also serve as the strength adjustable range in the same manner as above.

In the above embodiment and the modifications thereof, the plate-like body1is assembled to the midway part of the columnar body2. However, as shown inFIGS. 4(a) to 4(c), it is also possible to obtain the caulked assembly A in which the plate-like body1is assembled to an end part of the columnar body2so that an upper end surface of the columnar body2is made flush with the upper surface of the plate-like body1in the same manner as above. In the modification ofFIG. 4, the press apparatus4is composed of a first lower receiving tool44which includes a fitting hole44ainto which the columnar body2is fitted and supports the thick portion11of the plate-like body1in the axial direction, the thick portion11cylindrically protruding downward at the upper end of the columnar body2, a second lower receiving tool45which is arranged on the lower surface of the plate-like body1, includes a fitting hole45adefined by an inner circumferential surface thereof which comes into contact with the outer circumferential surface of the thick portion11and an outer circumferential surface of the first receiving tool44which supports the thick portion11, and is slidingly guided in the vertical axis direction along the outer circumferential surface of the first lower receiving tool44, and a press tool46which applies pressure on the upper end surface of the columnar body2and the upper surface of the plate-like body1in the axial direction from top to down.

By moving the press tool46downward, as shown inFIGS. 4(a) to 4(c), the press tool46presses down the plate-like body1, the columnar body2, and the second lower receiving tool45in an integrated manner, and only the thick portion11is thereby compressively pressed between the press tool46and an upper end surface of the first lower receiving tool44which does not move. Accordingly, the thick portion11whose position is restricted by the upper end surface of the first lower receiving tool44and the inner circumferential surface of the fitting hole45aof the second lower receiving tool45is plastically deformed toward the center of the mounting hole10and thereby fixed to the outer circumferential surface of the end part of the columnar body2by pressure. As a result, the caulked assembly A (FIG. 4(c)) in which the plate-like body1and the columnar body2are firmly integrated with each other can be obtained.

Further, such a press apparatus4is also not limited to the above structure as long as it can compressively press the thick portion11from the axial direction to thereby plastically deform the thick portion11toward the center of the mounting hole10so that the thick portion11is fixed to the outer circumferential surface of the columnar body2by pressure. For example, although pressure is applied to the press tool46and the applied pressure is received by the first lower receiving tool44in this modification, pressure may also, of course, be applied to the first lower receiving tool44by a pressure applying tool. The columnar body2and the second lower receiving tool45are biased upward by springs so as to integrally move downward with closely contacting with the lower surface of the press tool46. Further, although the first lower receiving tool44is placed on a cylindrical base member47, the base member47may also, of course, be integrally formed with the first lower receiving tool44.

Further, as shown inFIGS. 5(a) to 5(c), it is preferred to provide a plurality of holes14around the mounting hole10(the thick portion11) of the plate-like body1so that an adverse effect caused by excessive caulking (such as reduction of the perpendicularity of the columnar body2and deformation of the plate-like body1) can be prevented or reduced. The holes14are provided around the mounting hole10at regular intervals.

Further, it is also a preferred modification that a step portion12is formed around the mounting hole10of the plate-like body1, and the thick portion11is formed in an inner circumferential region of the step portion12as shown inFIG. 6(a). As will be described later in a description of a second embodiment, the step portion12achieves the same function as the thick portion11to be fixed to the outer circumferential surface of the columnar body2by pressure caulking by pressing a protruding side of the step portion12until the step is gone and becomes flat so that the step portion12is plastically deformed inwardly. However, in this modification, the step portion12is not pressed in this manner, and only the thick portion11is plastically deformed. The step portion12in this modification is used for positioning the press apparatus4.

Specifically, as shown inFIGS. 6(b) and 6(c), a fitting convex portion40cwhich is fitted into a depressed receiving portion12bon a lower surface of the step portion12is formed on an upper surface of the lower receiving portion40. Further, a notched groove41cwhich is fitted into a convex portion12aon an upper surface of the step portion12is formed on a lower surface of the upper receiving tool41. The other configurations are the same as those shown inFIGS. 1(a) to 1(c). By operating the pressure applying tool43to thereby move the press tool42downward, as shown inFIGS. 6(b) and 6(c), the press tool42presses the thick portion11downward. Accordingly, the thick portion11whose position is restricted by the upper surface of the lower receiving tool40and the inner circumferential surface of the fitting hole41aof the upper receiving tool41is plastically deformed toward the center of the mounting hole10and thereby fixed to the outer circumferential surface of the columnar body2by pressure. Such a configuration makes it possible to accurately assemble the columnar body2that is slimmer than the mounting hole10of the plate-like body1with the plate-like body1with the columnar body2positioned in the center of the mounting hole10. The step portion12can be efficiently manufactured by half blanking of press working.

In an example shown inFIGS. 6(b) and 6(c), the plate-like body1is assembled to the midway part of the columnar body2. However, as shown inFIGS. 7(a) and 7(b), the plate-like body1may be assembled to the end part of the columnar body2in the same manner as above by forming, on the lower surface of the press tool46, a fitting convex portion46cwhich is fitted into the depressed receiving portion12bon the upper surface of the step portion12, and forming, on the upper surface of the second lower receiving tool45, a notched groove45cwhich is fitted into the convex portion12aon the lower surface of the step portion12. The other configurations are the same as those of the modification shown inFIGS. 4(a) to 4(c). Further, it is also preferred to achieve the same function as the thick portion11to be fixed to the outer circumferential surface of the columnar body2by pressure caulking by pressing the protruding side of the step portion12so as to be plastically deformed inwardly, in the same manner as in the second embodiment. Such a modification overlaps with the second embodiment, and is effective in caulking of a slimmer shaft because the plastically deformed step portion12serves as a filler in addition to the thick portion11in this manner. That is, although when a slim shaft that has a diameter smaller than the diameter of a mounting hole is assembled to a plate-like body, the volume of a thick portion for filling a space between the slim shaft and the mounting hole may be insufficient when the thick portion is formed by burring, it is possible to cover the shortfall volume by crushing the step portion12formed by half blanking. Specifically, as shown inFIGS. 8(a)to8(c), the above modification can be achieved in such a manner that a press tool is divided into two tools, namely, the press tool42for pressing the thick portion11and a press tool42A for pressing the step portion12, the thick portion11is first plastically deformed by the press tool42, and the press tool42A then further moves downward in conjunction with the press tool42to thereby press the step portion12.

FIGS. 36 to 38illustrate a specific embodiment of the caulked assembly A according to the above-described manufacturing method of the first embodiment.FIG. 36illustrates a bulb-type lighting device5which includes a lens body81covering a light source80at a distal end thereof and a base58to be connected to an external power supply at a base end thereof. The light source80is supported on a surface of a light source support base82which is made of a highly thermal conductive material such as aluminum, the surface facing the distal end of the lighting device5(hereinafter, referred to as “a distal end side surface”). Inlet/outlet ports are provided on a wall surface of a housing7at a position closer to the base end of the lighting device5than the light source support base82. Further, a fan motor50is provided inside the housing7. A forced air flow is generated in and out of the housing7by the fan motor50through the inlet/outlet ports. Heat generated from the light source80is released from a surface of the light source support base82, the surface facing the base end of the lighting device5(hereinafter, referred to as “a base end side surface”), to the outside of the housing7by the forced air flow.

As shown inFIG. 37, in the light source support base82, there are formed through holes84for allowing strut members52of a power supply circuit unit56to penetrate therethrough to fix the strut members52to a lens fixing member83by mounting screws85. On the base end side surface of the light source support base82, there is provided a heat sink member6which is made of a highly thermal conductive material such as aluminum. The housing7is composed of a first case51and a second case54. The light source support base82is connected to a distal end of the first case51. The base58is provided on a base end of the second case54. Each of the inlet/outlet ports is provided on a side wall of each of the first case51and the second case54. A support plate53which has an opening at a central part thereof and is made of a highly thermal conductive material such as aluminum is provided inside the first case51at a position close to a connection border between the first case51and the second case54. Further, the fan motor50is fixed to the support plate53by mounting screws so as to close the opening.

Further, the power supply circuit unit56is arranged inside the housing7. Heat generated from the power supply circuit unit56is also released to the outside of the housing7by the forced air flow generated by the fan motor50. A resin case57is composed of a case main body57A provided at the distal end side and a cover57B provided at the base end side. The case main body57A and the cover57B are assembled with each other by mounting screws. The case main body57A is connected to the base end side surface of the light source support base82by the strut members52, so that the power supply circuit unit56is arranged inside the second case54at a position close to the connection border between the first case51and the second case54.

The strut members52are caused to penetrate the support plate53of the fan motor50, and the thus penetrated parts of the support plate53are fixed to the respective strut members52by the caulking method of the first embodiment. Further, the power supply circuit unit56is fixed to the thus penetrating end surfaces of the strut members52, the end surfaces facing the base end of the lighting device5. In this manner, the fan motor50and the power supply circuit unit56are supported by the strut members52. The strut members52and the support plate53are caulked with each other, for example, by the caulking method as shown inFIGS. 1(a) to 3(c)in which through holes are provided in the support plate53, the periphery of each of the through holes is made thick by burring, and the thick portion is compressed in the axial direction of each of the strut members52to thereby fix the support plate53to the strut members52by pressure. In addition, the various caulking methods of the first embodiment can be utilized. Further, caulking methods of later-described second, third and fourth embodiments can also, of course, be employed. One end of each of the strut members52, the one end facing the distal end of the lighting device5, penetrates a through hole84of the light source support base82, and then comes into contact with the lens fixing member83and is fixed thereto by screwing a mounting screw85which penetrates a through hole provided in the lens fixing member83at a position corresponding to the contact position with each of the strut members52toward the base end of the lighting device into a screw hole52awhich is formed on one of end surfaces of each of the strut members52. Further, the other end of each of the strut members52, the other end facing the base end of the lighting device5, comes into contact with the case main body57A of the resin case57of the power supply circuit unit56, and is fixed thereto by screwing a mounting screw86which penetrates a through hole provided in the case main body57A at a position corresponding to the contact position with each of the strut members52toward the distal end of the lighting device5into a screw hole52bwhich is formed on the other end surface of each of the strut members52. In this embodiment, each of the strut members52is caulked with the support plate53at a position in which the screw hole52bis formed. Even in the case of such caulking with a hollow shaft, it is possible to perform the assembly with sufficient strength without deformation of the shaft by means of the method of the first embodiment.

Further,FIG. 38illustrates a modification of the heat sink member6of the lighting device5illustrated inFIGS. 36 and 37. In this modification, hollow or solid columnar bodies6deach of which is made of a highly thermal conductive metal are used as fins. A plate-like base member6bwhich constitutes a support and is also made of a highly thermal conductive metal is subjected to press working to thereby fix the columnar bodies6dto the plate-like base member6bby caulking, so that the columnar bodies6dare provided in a standing manner on a surface of the plate-like base member6b, the surface facing the base end of the lighting device5. The columnar bodies6dare fixed to the plate-like base member6bby caulking, for example, in such a manner that, as shown inFIGS. 1(a) to 3(c), mounting holes for inserting and fixing the respective columnar bodies6dare provided in the plate-like base member6bwhich constitutes support, thick portions6eare formed along inner circumferential edges of the mounting holes by burring, and the thick portions6eare compressively pressed from the axial direction of the columnar bodies6dwith the columnar bodies6dinserted into the respective mounting holes so that the thick portions6eare plastically deformed toward the centers of the respective mounting holes to thereby fixe the thick portions6eto outer circumferential surfaces of the columnar bodies6dby pressure. In addition, the various caulking methods of the first embodiment can be utilized. Further, caulking methods of the later-described second, third and fourth embodiments can also, of course, be employed.

Although each of the columnar bodies6dis formed into a hollow pipe to increase the surface area thereof, each of the columnar bodies6dmay be solid. Further, in this modification, each of the columnar bodies6dhas a hollow pipe shape and penetrates the support (the plate-like base member6b). Therefore, spaces on opposite sides of the plate-like base member6bcommunicate with each other through the columnar bodies6d. As a result, the columnar bodies6dachieve a stack effect for circulating air from a part having a higher temperature to a part having a lower temperature, thereby making it possible to further facilitate cooling. In the structure of this modification, since the plate-like base member6b(namely, bottoms of the columnar bodies6d) is closely attached to the surface of the light source support member82, there is no circulation of air and the stack effect does not, therefore, occur. However, it is possible to achieve the stack effect depending on the structure of a subject of cooling. Further, although not shown in the figures, by forming a hole which serves as an inlet for air on an outer wall of each of the columnar bodies6dat a position near the bottom thereof, air is circulated inside the columnar bodies6ddue to the stack effect, thereby making it possible to enhance heat releasing effect for releasing heat within the columnar bodies6dto the outside. Although a cross section of each of the columnar bodies6dhas a circular shape, the cross section may also, of course, have a quadrate shape, an elliptical shape, an irregular shape, and the like. Even in the calking of the hollow columnar bodies6dwith the plate-like base member6bas performed in this modification, it is possible to assemble the columnar bodies6dwith the plate-like member6bwith sufficient strength without deformation of the columnar bodies6dby means of the method of the first embodiment.

Next, the second embodiment of the present invention will be described with reference toFIGS. 9 to 17(b).

In the second embodiment, as shown inFIG. 9, a mounting hole10for inserting and assembling a columnar body2is provided in a metallic plate-like body1, and a step portion12is formed around the mounting hole10. As shown inFIG. 10(a), the columnar body2is inserted into the mounting hole10of the plate-like body1so that the plate-like body1is set in an assembly position on an outer circumferential surface of the columnar body2. Further, as shown inFIG. 10(b), the step portion12is compressively pressed from an axial direction of the columnar body2so as to be plastically deformed toward a center of the mounting hole10to thereby tighten and fix an inner circumferential part of the mounting hole10to the outer circumferential surface of the columnar body2. The step portion12can be efficiently manufactured by half blanking of press working.

Especially, in the present embodiment, since a depressed surface of the step portion12is determined as a receiving portion12b, and the step portion12is deformed by applying pressure to the other protruding surface (a convex portion12a), the columnar body2is firmly held in the center of the mounting hole10with the plate-like body1positioned by the receiving portion12b. Therefore, even when the columnar body2is slimmer than the mounting hole10, the columnar body2can be accurately and reliably assembled in the center of the mounting hole10.

Specifically, as shown inFIGS. 10(a) and 10(b), a fitting convex portion46cwhich is fitted into the receiving portion12bof the step portion12is formed on a lower surface of a press tool46. A first lower receiving tool44supports the convex portion12aas well as a part of a second lower receiving tool45at an outer circumferential side thereof, the part not corresponding to the step portion12. The other configurations are the same as those of the press apparatus4in the modification shown inFIGS. 4(a) to 4(c).

By moving the press tool46downward, as shown inFIGS. 10(a) and 10(b), the press tool46presses down the plate-like body1, the columnar body2and the second lower receiving tool45in an integrated manner, and only the step portion12is thereby compressively pressed between the fitting convex portion46cof the press tool46and an upper end surface of the first lower receiving tool44which does not move. Accordingly, the convex portion12aof the step portion12whose position is restricted by the upper end surface of the first lower receiving tool44and an inner circumferential surface of a fitting hole45aof the second lower receiving tool45is plastically deformed toward the center of the mounting hole10and thereby fixed to an outer circumferential surface of an end part of the columnar body2by pressure. As a result, the caulked assembly A (FIG. 10(b)) in which the plate-like body1and the columnar body2are firmly integrated with each other can be obtained. In this embodiment, the convex portion12ais deformed so as to completely lose its shape. However, the convex portion12amay also, of course, remain in some degree.

In this embodiment, the plate-like body1is assembled to the end part of the columnar body2. However, it is also, of course, possible to assemble the plate-like body1to the midway part of the columnar body2. In this case, as shown inFIGS. 11(a) and 11(b), in a press apparatus4having the same basic configuration as that of the press apparatus4ofFIGS. 1(a) to 1(c), a fitting convex portion40cis formed on a lower receiving tool40, and the convex portion12ais pressed by a press tool42in the same manner as above.

Further, as shown inFIGS. 12(a) and 12(b), it is also a preferred modification that a circumferential groove20having a predetermined depth is formed at the assembly position on the outer circumferential surface of the columnar body2, and, in a caulking step, the step portion12is compressively pressed from the axial direction of the columnar body2so as to be plastically deformed toward the center of the mounting hole10to thereby tighten and fix an inner circumferential part10aof the mounting hole10to the outer circumferential surface of the columnar body2as well as cause the inner circumferential part10ato bite into the circumferential groove20as shown inFIG. 12(b).

Further, as shown inFIGS. 13(a) and 13(b), in a modification in which the fitting convex portion46cof the press tool46is formed so as to protrude only into the outer circumferential side of the receiving portion12bof the step portion12so that the fitting convex portion46cis not completely fitted into the receiving portion12b, but a space s1is formed at the inner circumferential side thereof, the positioning of the plate-like body1can be performed by the fitting convex portion46cwhich is fitted into the receiving portion12bat the outer circumferential side thereof. In addition, the space s1can be made to serve as the caulking strength adjustable range. Further, the convex portion12aof the step portion12can be reliably deformed toward the center of the mounting hole10by leading the plastically deformed convex portion12ainto the space s1. Although, in order to enhance such an effect, an inner circumferential surface of the fitting convex portion46cis formed into an inclined surface in this modification, the shape of the inner circumferential surface of the fitting convex portion46cis not limited thereto. Further, the inclined surface of the inner circumferential surface of the fitting convex portion46calso serves as a draft angle for making it easy to remove the fitting convex portion46cfrom the receiving portion12bafter processing. Further, it is also preferred to form a drat angle also in the outer circumferential surface of the fitting convex portion46caccording to the need.

Also in this case, as shown inFIGS. 14(a) and 14(b), it is also preferred that the circumferential groove20having a predetermined depth be formed at the assembly position on the outer circumferential surface of the columnar body2, and, in the caulking step, the step portion12be compressively pressed from the axial direction of the columnar body2so as to be plastically deformed toward the center of the mounting hole10to thereby tighten and fix the inner circumferential part10aof the mounting hole10to the outer circumferential surface of the columnar body2as well as cause the inner circumferential part10ato bite into the circumferential groove20as shown inFIG. 14(b).

Although, in the above embodiment and the modifications thereof, the step portion12is formed in a region leading to the inner circumferential surface of the mounting hole10, the step portion12may be formed in a region that is separated from the inner circumferential edge of the mounting hole10so as to have a ring shape that is generally concentric with the mounting hole10as shown inFIGS. 15(a) and 15(b).FIGS. 16(a) and 16(b)illustrate a modification in which the circumferential groove20having a predetermined depth is further formed at the assembly position on the outer circumferential surface of the columnar body2in addition to the configuration of the modification shown inFIGS. 15(a) and 15(b), and the inner circumferential part10aof the mounting hole10is tightened and fixed to the outer circumferential surface of the columnar body2as well as caused to bite into the circumferential groove20. InFIGS. 16(a) and 16(b), a reference numeral48indicates a guide member for crushing the step portion12in the axial direction of the columnar body2. In the modifications shown inFIGS. 13(a) to 16(b), since a span for holding the columnar body2can be made wide, the accuracy and the like are stable.

Further, as shown inFIGS. 17(a) and 17(b), it is also a preferred modification that a thick portion11is formed along the inner circumferential edge of the mounting hole10in addition to the step portion12, and the step portion12and the thick portion11are compressively pressed to thereby fix the step portion12and the thick portion11to the outer circumferential surface of the columnar body2by pressure. In this case, a notched groove44bwhich receives the thick portion11protruding further downward than the convex portion12ais formed on the upper surface of the first lower receiving tool44. Accordingly, as shown inFIGS. 17(a) and 17(b), both of the convex portion12aof the step portion12and the thick portion11are deformed toward the center of the mounting hole10and thereby fixed to the outer circumferential surface of the columnar body2by pressure.

The columnar body, the plate-like body, the configuration of the press apparatus, and the modifications thereof of the second embodiment are basically the same as those of the first embodiment. Therefore, the same reference signs are used to refer to the same elements, and a description thereof will therefore be omitted. Especially, also in the embodiment and the modifications thereof shown inFIGS. 9 to 17(b), it is preferred to provide a plurality of holes as shown inFIGS. 5(a) to 5(c)around the mounting hole10and the step portion12of the plate-like body1so that an adverse effect caused by excessive caulking (such as reduction of the perpendicularity of the columnar body2and deformation of the plate-like body1) can be prevented or reduced. Providing the holes in this manner is preferred especially when a columnar body that does not have a circumferential groove is assembled to a plate-like body by caulking. Further, the step portion12is not limited to one formed along the whole circumference of the mounting hole10. For example, the step portion12may be formed in a part of the circumference of the mounting hole10. Further, when the step portion12is formed in a part of the circumference of the mounting hole10, the step portion12is not limited to one formed in a single location, but may be divided and formed in a plurality of locations. These forms of the step12are appropriately selected depending on the intended use. In particular, when caulking is performed on the step portion12divided and formed in a plurality of locations on the circumference of the mounting hole10, tightening stress is reduced compared to the case where caulking is performed with the step portion12formed along the whole circumference of the mounting hole10. As a result, an adverse effect caused by excessive caulking can be reduced as well as the caulking strength adjustable range is made broader. These forms can also be appropriately selected depending on the intended use.

FIGS. 39 to 43(f) illustrate specific embodiments of the caulked assembly A according to the manufacturing method of the above-described second embodiment, and modifications of the heat sink member6of the lighting device5illustrated inFIGS. 36 and 37. In these modifications, solid plate-like columnar bodies6aeach of which is made of a highly thermal conductive metal are used as fins. The plate-like base member6bwhich constitutes a support and is also made of a highly thermal conductive metal is subjected to press working to thereby fix the columnar bodies6awhich are radially arranged to the plate-like base member6bby caulking, so that the columnar bodies6aare provided in a standing manner on a surface of the plate-like base member6d, the surface facing the base end of the lighting device5.

The columnar bodies6aare fixed to the plate-like base member6bby caulking in the same manner as shown inFIGS. 9 to 10(b). That is, as shown inFIGS. 41(b) and 41(c), for example, the mounting holes10(square holes) for inserting and fixing the plate-like columnar bodies6aare provided in the plate-like base member6bwhich constitutes the support, and the step portions12are formed around the respective mounting holes10. The plate-like columnar bodies6aare inserted into the respective mounting holes10of the plate-like base member6band set in respective assembly positions. Then, each of the step portions12is compressively pressed from the axial direction of each of the columnar bodies6aso as to be plastically deformed toward the center of each of the mounting holes10to thereby tighten and fix an inner circumferential part of each of the mounting holes10to the outer circumferential surface of each of the columnar bodies6aas shown inFIG. 41(c). Further, by providing a through hole in a base end part of each of the plate-like columnar bodies6a, the base end part being tightened and fixed to the plate-like base member6b, each of the plastically deformed step portions12is caused to bite into the thus provided through hole, thereby making it possible to further enhance the supporting strength. Further, the caulking method of the first embodiment and caulking methods of the later-described third and fourth embodiments can also, of course, be employed.

As shown inFIGS. 42(a) to 42(c), it is also a preferred modification that the step portion12formed by half blanking is formed around each of the square mounting holes10only at one side of each of the columnar bodies6a, and the step portion12is therefore tightened and fixed from the one side. Accordingly, the inner surface of each of the mounting holes10at the other side is maintained as a cut surface. Therefore, excellent position accuracy and excellent perpendicularity of the columnar bodies6awhich are pressed against the inner surfaces of the mounting holes10are maintained. Further, it is also a preferred modification that, as shown inFIGS. 43(a) to 43(f), the step portions12are provided at both sides of each of the columnar bodies6, and only one of the step portions12that is provided at one of the sides of each of the columnar bodies6ais pressed to thereby tighten and fix the inner circumferential surface of each of the mounting holes10to each of the columnar bodies6aonly from the one side. In such a modification, the step portion12is formed also at the other side of the columnar body6a, and both ends in the width direction of the columnar body6aare positioned so as to correspond to both ends of the mounting hole10. In addition, the step portion12is not formed on the both ends of each of the mounting holes10(In the modifications shown inFIGS. 41(a) to 43(f), each of the step portions12is provided not throughout the entire width of each of the columnar bodies6a, but within a predetermined range in an intermediate part other than the both ends as shown inFIG. 43(d)). Therefore, the columnar body6ais supported between a bottom surface of the support (the plate-like base member6b) and an upper end of the step portion12at the other side (namely, a span d1inFIG. 43(d)), and tightening pressure from the one side is applied within the span d1as well as near the center of the columnar body6ain the width direction thereof. Accordingly, the span d1is made wider, and a good balance of pressure support is ensured, thereby further improving the accuracy. Although, in the modifications shown inFIGS. 41(a) to 43(f), the step portion12is configured so as to apply pressure to the predetermine range in the intermediate part of the columnar body6aother than the both ends thereof, the width of the step portion12may be the same as the width of the columnar body6a. For example, as shown inFIG. 43(e), it is also preferred to reduce only the width of the lower end part of the columnar body6awhich is inserted and fitted into the mounting hole10so that the width of the step portion12is made to be the same as the width of the lower end part of the columnar body6a. Further, in a case where the columnar body6ais in the form shown inFIG. 43(e), and a relationship between the mounting hole10and the step portion12is one shown inFIG. 43(d), it is needless to say that the columnar body6ais supported within the span d1in the same manner as above and the accuracy is therefore further improved. Further, the columnar body6amay have a U-shaped or L-shaped cross section as shown inFIGS. 40(a) and 40(b)other than a straight plate-like shape. In this case, the columnar body6aand the plate-like base member6bcan be fixed by caulking in such a manner that the mounting hole10is formed so as to have a size that is capable of inserting a wide region on the lower end part of the columnar body6a, and, in the same manner as above, the step portion12of the plate-like base member6bis plastically deformed and thereby fixed to the lower end part of the columnar body6aby pressure.FIG. 43(f)illustrates a modification in which a concave portion h1is provided in the columnar body6a, and the step portion12is caused to bite into the concave portion h1. The concave portion h1may or may not penetrate the columnar body6a. The number and the shape of the concave portion h1may be appropriately determined depending on the size or the intended purpose. Besides a square hole, a round hole, an irregular hole and the like can, of course, be employed as the shape of the concave portion h1.

Next, the third embodiment of the present invention will be described with reference toFIGS. 18(a) to 23(b).

In the present embodiment, as shown inFIGS. 18(a) and 18(b), a metallic plate-like body1in which a prepared hole is not provided is subjected to burring to thereby provide a mounting hole10for inserting and assembling a columnar body2and also form a thick portion11having a cylindrical shape along an inner circumferential edge of the mounting hole10by burring. Thereafter, in the same manner as in the first embodiment, the columnar body2is inserted into the mounting hole10of the plate-like body1so that the plate-like plate1is set in an assembly position on an outer circumferential surface of the columnar body2as shown inFIG. 19(a). Then, as shown inFIGS. 19(b) and 19(c), the thick portion11is compressively pressed from the axial direction of the columnar body2so as to be plastically deformed toward a center of the mounting hole10to thereby tighten and fix the thick portion11to the outer circumferential surface of the columnar body2. Further, a depression1ais formed on the plate-like body1ofFIG. 18(a)at a position corresponding to the center of the mounting hole10to be formed so that burring can be substantially uniformly performed even without a prepared hole.

In an example shown inFIGS. 19(a) to 19(c), a caulked assembly can be manufactured using the same press apparatus4as that shown inFIGS. 1(a) to 1(c)of the first embodiment. Also, in the same manner as in the first embodiment, a bent corner11aon the inner circumference of the mounting hole10is formed into an R shape due to shear drop at the time of burring, and a space between the corner11aand the apparatus serves as the caulking strength adjustable range. Further,FIGS. 20(a) to 20(c)illustrate a modification in which the columnar body2that is slimmer than the mounting hole10is assembled to the plate-like body1. The present embodiment is characterized in that, since there is no prepared hole in the plate-like body1as described above, it is possible to fix a columnar body that is made slim to the limit of obtaining necessary filling volume to the plate-like body1by caulking.

Also in the present embodiment, the plate-like body1can be assembled to the midway part of the columnar body2, and can also be assembled to the end part thereof as with the above-described first and second embodiments.FIGS. 21(a) and 21(b)illustrate a modification in which the plate-like body1is assembled to an end part of the columnar body2. Basically, the caulked assembly can be manufactured using the same press apparatus4as that shown inFIGS. 4(a) to 4(c)of the first embodiment. Further, as shown inFIGS. 22(a) and 22(b), it is also a preferred modification that the thick portion11is formed into a circular truncated cone shape which is tapered toward the tip thereof by burring. The columnar body2is inserted into the small-diameter tip part of the mounting hole10. Accordingly, the expansion amount of the tip by burring is reduced, thereby reducing non-uniformity of the tip.

Further, in the present embodiment, it is also a preferred modification that a circumferential groove20having a predetermined depth is formed in the assembly position on the outer circumferential surface of the columnar body2, and, as shown inFIG. 23(b), in the caulking step, the thick portion11is compressively pressed from the axial direction of the columnar body2so as to be plastically deformed toward the center of the mounting hole10to thereby tighten and fix the thick portion11to the outer circumferential surface of the columnar body2as well as cause the thick portion11to bite into the circumferential groove20in the same manner as in the second embodiment. Since the burring is performed on the plate-like body1in which a prepared hole is not provided, an end surface of the thick portion11may be non-uniform as shown inFIG. 18(b). However, since the thick portion11is plastically deformed by applying pressure, such non-uniformity is made uniform after the caulking. Further, in a case where the columnar body2that is slimmer than the mounting hole10is assembled with the plate-like body1, it is also a preferred modification that, in order to achieve high assembling accuracy, the step12as shown inFIGS. 6(a) to 6(c)is formed, and the columnar body2is positioned after positioning the plate-like body1as shown inFIGS. 7(a) and 7(b).

The columnar body, the plate-like body, the configuration of the press apparatus, and the modifications thereof of the third embodiment are also basically the same as those of the first embodiment. Therefore, the same reference signs are used to refer to the same elements, and a description thereof is therefore omitted.

Next, the fourth embodiment of the present invention will be described with reference toFIGS. 24(a) to 35(b).

In the present embodiment, as shown inFIGS. 24(a) and 24(b), a holding member3having a mounting hole30into which a columnar body2is inserted is interposed between a plate-like body1and the columnar body2to thereby assemble the plate-like body1with the columnar body2by caulking. In particular, a fitting hole13into which the holding member3is fitted is previously provided in the plate-like body1, and the holding member3is fitted into the fitting hole13. The columnar body2is then inserted into the mounting hole30of the holding member3as shown inFIG. 24(a)so that the plate-like body1and the holding member3are set in an assembly position on an outer circumferential surface of the columnar body2. Thereafter, as shown inFIG. 24(b), the holding member3is compressively pressed from the axial direction of the columnar body2so as to be plastically deformed both inwardly and outwardly, namely, toward a center of the mounting hole30and also toward an inner circumferential surface of the fitting hole13of the plate-like body1to thereby tighten and fix the holding member3to the outer circumferential surface of the columnar body2as well as cause the holding member3to spread within an inner circumferential part of the fitting hole13of the plate-like body1so as to be fixed thereto.

This method is characterized in that a remaining part of a washer due to insufficient caulking is not generated, a plate-like body can be assembled with the columnar body that does not have a flange and the like, a caulked assembly can be made thin, and caulking can be performed by a single step without performing press-fitting, thereby making it possible to perform the assembly with high working efficiency as well as at a low cost, and also obtain a thin assembly with high accuracy. Basically, the same press apparatus4as that shown inFIGS. 1(a) to 1(c)of the first embodiment can be used. Instead of the thick portion11, the holding member3is compressively pressed in the axial direction between the press tool42and the lower receiving tool40. The holding member3is also preferably made of metal, but not limited thereto. The holding member3is preferably made of, for example, resin as appropriate. In this case, it is preferred to heat the caulking apparatus or apply ultrasonic vibration to plastically deform the holding member3with higher accuracy. In a case where the holding member3is made of metal, a metallic material that is easily plastically deformed such as brass and aluminum is preferably used. However, the material of the holding member3is not limited thereto, and can be appropriately selected according to the intended purpose such as holding strength and accuracy.

In the embodiment shown inFIGS. 24(a) and 24(b), the plate-like body1is assembled to the midway part of the columnar body2. However, as shown inFIGS. 25(a) and 25(b), the plate-like body1may also, of course, be assembled to the end part of the columnar body2. Further, as shown inFIGS. 26(a) and 26(b), it is also a preferred modification that a circumferential groove20having a predetermined depth is formed at the assembly position on the outer circumferential surface of the columnar body2, and, in the caulking step, the holding member3is compressively pressed from the axial direction of the columnar body2to thereby fix the holding member3to the outer circumferential surface of the columnar body2by pressure as well as cause the holding member3to bite into the circumferential groove20in the same manner as in the second embodiment.

The fixing of the holding member3to the inner circumferential part of the fitting hole13of the plate-like body1is preferably performed in such a manner that the holding member3is fixed to an inner circumferential surface of the fitting hole13by the spread thereof, and the holding member3is also plastically deformed so as to cover a part of one or both of an upper surface and a lower surface of the plate-like body1around the fitting hole13and is thereby fixed thereto. For example,FIGS. 27(a) and 27(b)illustrate a modification in which a flange portion31which is engaged with the lower surface of the plate-like body1around the fitting hole13is previously provided on an end of the holding member3. Further, a space is set between an outer circumferential surface of the holding member3and the fitting hole41aof the upper receiving tool41. Accordingly, the plate-like body1is brought into a state where an area surrounding the fitting hole13protrudes into the set space and comes into contact with the outer circumferential surface of the holding member3. By applying pressure to the holding member3in the axial direction of the columnar body2, the holding member3is plastically deformed so as to cover a part of the upper surface of the plate-like body1, the part surrounding the fitting hole13, to thereby fix the holding member3to the plate-like body1so that the area surrounding the fitting hole13of the plate-like body1is surroundingly supported by the holding member3from both of the upper and lower surfaces thereof as shown inFIG. 27(b). As a result of this, the assembly strength is dramatically improved.

FIGS. 28(a) and 28(b)illustrate a modification in which the circumferential groove20having a predetermined depth is further formed at the assembly position on the outer circumferential surface of the columnar body2in addition to the configuration of the modification shown inFIGS. 27(a) and 27(b), and the holding member3is caused to bite into the circumferential groove20in the caulking step. As a result of this, the assembly strength is further improved.

FIGS. 29(a) to 29(c)illustrate a modification in which an inclined surface13ais formed on an upper opening edge of the fitting hole13of the plate-like body1so that the upper opening edge is formed into a tapered shape whose diameter is reduced toward the inside of the fitting hole13, and the holding member3is plastically deformed and thereby fixed to the inclined surface13aby pressure. When a depression (the inclined surface13aon the opening edge in this modification) is formed on the inner circumferential surface of the fitting hole13in this manner, a firm structure in which the area surrounding the fitting hole13of the plate-like body1is surroundingly supported by the holding member3is achieved as with the modification shown inFIGS. 27(a) and 27(b), and, at the same time, it is possible to provide a product having a flat upper surface as an assembly.FIGS. 30(a) and 30(b)illustrate a modification in which the circumferential groove20having a predetermined depth is further formed at the assembly position on the outer circumferential surface of the columnar body2in addition to the configuration of the modification shown inFIGS. 29(a)and29(b), and the holding member3is caused to bite into the circumferential groove20in the caulking step. As a result of this, the assembly strength is further improved.

Further, as shown inFIGS. 31(a) to 31(d), by forming depressions (upper and lower inclined surfaces13a) on both of upper and lower opening edges of the fitting hole13, it is possible to provide a product in which the area surrounding the fitting hole13is surroundingly supported by the holding member3, and the holding member3and the plate-like body1are assembled so as to have flat upper and lower surfaces. In this case, the flange portion31of the holding member3is not required. In this modification, as shown inFIGS. 31(b) to 31(d), the assembly can be reliably performed by dividing a manufacturing process into two steps including a step of plastically deforming a lower end of the holding member3so as to be fixed to the lower inclined surface13aof the fitting hole13by pressure, and a step of plastically deforming an upper end of the holding member3so as to be fixed to the upper inclined surface13aof the fitting hole13by pressure. Although the manufacturing process is divided into the two steps in this modification as just described, the manufacturing process may also, of course, be performed by a single step. When performing the manufacturing process by a single step, there is no problem if the upper end and the lower end of the holding member3are uniformly crashed. However, if the upper end and the lower end of the holding member3are alternately crashed, the processing may be performed with a relative position between the plate-like body1and the columnar body2in the axial direction of the columnar body2varying, which may cause variation in the accuracy and the holding strength. Therefore, in order to reliably and accurately perform the assembly, it is preferred to separately process the upper end and the lower end of the holding member3by the two steps.

More specifically, a press apparatus4is composed of a first lower receiving tool44which supports the holding member3from the lower surface thereof, a second lower receiving tool45which is slidingly guided up and down along an outer circumferential surface of the first lower receiving tool44and supports the plate-like body1from the lower surface thereof with being biased by a spring, a press tool42which presses the holding member3downward from the upper surface thereof in the axial direction of the columnar body2, an upper receiving tool41which is slidingly guided up and down along an outer circumferential surface of the press tool42, and presses and supports the plate-like body1from the upper surface thereof with being biased downward by a spring, a first pressure applying tool43A which integrally presses down the press tool42, the upper receiving tool41and the columnar body2which is biased upward by a spring and therefore movable, and a second pressure applying tool43B which can apply pressure only to the press tool42.

First, as shown inFIGS. 31(b) and 31(c), the press tool42, the upper receiving tool41and the columnar body2are integrally pressed downward by the first pressure applying tool43A. Accordingly, the plate-like body1and the second lower receiving tool45also integrally move downward. The lower end of the holding member3is thereby plastically deformed by applied pressure between the plate-like body and the first lower receiving tool44which does not move, and fixed to the lower inclined surface13aby pressure. Preferably, a relative movement distance of the second lower receiving tool45with respect to the first lower receiving tool44is determined so that the lower surface of the holding member3is made generally flush with the lower surface of the plate-like body1in the above state. Then, the first pressure applying tool43A is replaced with the second pressure applying tool43B, and only the press tool42is pressed downward by the second pressure applying tool43B. As a result, as shown inFIG. 31(d), the upper end of the holding member3is plastically deformed by the applied pressure, and thereby fixed to the upper inclined surface13aby pressure and assembled thereto so that the upper surface of the holding member3and the upper surface of the plate-like body1are made flat.

FIGS. 32(a) to 32(c)illustrate a modification in which the circumferential groove20having a predetermined depth is further formed at the assembly position on the outer circumferential surface of the columnar body2in addition to the configuration of the modification shown inFIGS. 31(a) to 31(d), and the holding member3is caused to gradually bite into the circumferential groove20by two caulking steps. As a result of this, the assembly strength is further improved. Although depressions on the inner circumferential surface of the fitting hole13are composed of the inclined surfaces13aon the opening edges in this modification, it is also a preferred modification that a similar circumferential groove is formed on the midway part, in the axial direction of the columnar body2, of the inner circumferential surface of the fitting hole13as a depression, and the holding member3is caused to bite into the thus formed circumferential groove.

Further, as shown inFIGS. 33(a) to 33(d), it is also a preferred modification that a depression (the inclined surface13a) on the inner circumferential surface of the fitting hole13is formed only on one of the opening edges thereof (the upper opening edge), the one edge being positioned at a side in which the resulting surface is desired to be flat, the inclined surface13ais not formed on the other opening edge thereof (the lower opening edge) and the flange portion31is also omitted, and pressure is applied to the lower end of the holding member3, the lower end protruding further downward than the plate-like body1, so that the lower end of the holding member3is plastically deformed so as to cover a part of the lower surface of the plate-like body1around the fitting hole13, to thereby fix the holding member3to the plate-like body1so that an area surrounding the fitting hole13of the plate-like body1is surroundingly supported by the holding member3from both of the upper and lower surfaces thereof. In this case, the same press apparatus4as that in the modification shown inFIGS. 31(a) to 31(d)can be used. Also in this case,FIGS. 34(a) to 34(c)illustrate modification in which the circumferential groove20having a predetermined depth is further formed at the assembly position on the outer circumferential surface of the columnar body2in addition to the configuration of the modification shown inFIGS. 33(a) to 33(d), and the holding member3is caused to gradually bite into the circumferential groove20by the two caulking steps. As a result of this, the assembly strength is further improved.

Further, it is also a preferred modification that, in order to increase a contact area between the holding member3and the outer circumferential surface of the columnar body2in a state of being fixed to each other by caulking (in an assembled state), as shown inFIGS. 35(a) and 35(b), an inner circumferential edge of a pressure applying surface (a lower end surface) of the press tool42which applies pressure to the holding member3, the inner circumferential edge facing the columnar body2, is taperedly notched, and the holding member3is plastically deformed into a space s3formed between the thus notched edge and the outer circumferential surface of the columnar body2to thereby increase the contact area. Although the holding member3has an annular shape in the present embodiment, the holding member3may also be formed into a part of an annular shape (a generally C-shape, for example), and these shapes can be appropriately selected depending on the intended use. Further, the shape of the holding member3can be appropriately selected depending on, for example, the shape of the columnar body2(a circular shape, a square shape, a plate-like shape and the like). For example, a modification in which the step portion12to be crushed shown inFIGS. 39 to 43(f) is replaced with the holding member3is also possible.

In the above, the embodiments of the present invention have been described. However, the present invention is not limited to these embodiments and may, of course, be embodied in various forms without departing from the scope of the invention. For example, although the circumferential groove20of each of the embodiments is a concave portion which is formed along the whole circumference of the columnar body2, the circumferential groove20may also be formed in a part of the circumference of the columnar body2as long as it has a concave shape. That is, all concave shapes (thorough or non-through) may be employed as the shape of the circumferential groove20as long as it is capable of causing an object to bite thereinto. These forms can be appropriately selected depending on the intended use.

REFERENCE SIGNS LIST