DESCRIPTION Title of Invention Pillar terminal and its manufacturing method Technical Field [0001] The present invention relates to a pillar terminal for fixing an electric wire inserted into a terminal frame of a hollow cylindrical shape by a terminal screw, the pillar terminal is mounted on a switching device, and manufacturing method of the pillar terminal. Background Art [0002] A pillar terminal for electrically connecting an electric wire to a conductor leading to an electric contact of a switching circuit and fixing them by using a terminal screw, where the wire is inserted into a cylindrical frame of the pillar terminal, is known in the prior art (for example, refer to Patent Literature 1). Citation List Patent Literature [0003] Patent Literature 1: JP2011-1085 86A Summary of Invention Technical Problem [0004] In the pillar terminal shown in the Patent Literature 1 mentioned above, four parts such as: an intermediate conductor to be electrically connected to the electric contact, the electric wire, the terminal frame, and the terminal screw are involved when the electric wire is electrically connected to the electric contact, and parts management and handling are complicated. It is desired to make these user-friendly and also to attain low cost. [0005] The present invention is to solve the above problem, and an object of the present invention is to provide a pillar terminal and its manufacturing method which can realize a easy handling at manufacturing and low cost pillar terminal unified with an electric contact which is a component of a switching device. Solution to Problem [0006] In order to achieve the above purpose, the present invention provides a pillar terminal for fixing an electric wire, which is mounted on a switching device, comprising: a terminal frame of a hollow cylindrical shape into which the electric wire is to be inserted; a terminal screw for fixing the electric wire inserted into the terminal frame; and a conductor having a head for an electric contact of the switching device, wherein the terminal frame is an iron-made frame having two surfaces facing mutually, the one of the surfaces has a screw hole into which the terminal screw is inserted, and the other of the surfaces has a through hole into which an end of the conductor opposite to the electric contact is inserted, and the conductor is fixed to the terminal frame by clinching the end of the conductor inserted into the through hole from an outside of the terminal frame, and the terminal screw is screwed into the screw hole to press the electric wire inserted into the terminal frame against the end of the conductor and to connect the electric wire to the conductor electrically. [0007] In the pillar terminal, preferably the size of the end of the conductor extended by the clinching is larger than the aperture of the screw hole. [0008] In the pillar terminal, preferably the terminal frame has a plating layer of which conductivity is higher than the iron of the terminal frame, the plating layer is equipped on an area that the end of the conductor extended by the clinching touches and on outskirts of the area, wherein the area and its outskirts are the inner surface of the terminal frame. [0009] In the pillar terminal, preferably the terminal frame has a metal plate of which conductivity is higher than the iron of the terminal frame, the metal plate is equipped on an area that the end of the conductor extended by the clinching touches and on outskirts of the area, wherein the area and its outskirts are the inner surface of the terminal frame. [0010] In the pillar terminal, preferably the terminal frame has a recess at an inside edge of the through hole, and the conductor is prevented from rotating by getting itself into the recess by the clinching. [0011] In he pillar terminal, preferably the terminal frame is fixed to an insulating substrate, which is a component of the switching device, by the clinching of the conductor, and the terminal frame has a projection in a surface facing the substrate and is prevented from rotating by sticking the projection into the substrate. [0012] Further, the present invention provides a method for manufacturing the pillar terminal, comprising the steps of: an inserting step for inserting the end of the conductor into the through hole so that the end protrudes inside the terminal frame; and a clinching step for fixing the conductor to the terminal frame by introducing a punch through the screw hole, and clinching the protruding end after the inserting step using the punch. [0013] In the method, preferably the clinching step extrudes the material of the conductor into the outside of the punch to make the end of the conductor larger than the screw hole. [0014] In the method, preferably the clinching step depresses growth of an edge in the material extruded into the outside of the punch by using a press plate for pressing the extruded material. Advantageous Effects of Invention [0015] According to the pillar terminal and its manufacturing method of the present invention, since an end of the conductor having the electrical contact is fixed to the terminal frame by the clinching, the number of parts count for wire connection can be decreased and the wire can be electrically connected to the electrical contact only by fixing the wire to the pillar terminal. Therefore, handling parts at manufacturing becomes easy, and also a cost reduction can be realized. Brief Description of Drawings [0016] FIG. 1A is a perspective view of a pillar terminal according to an embodiment of the present invention seen from a screw hole side, FIG 1B is a perspective view of the pillar terminal seen from an electric contact side, and FIG 1C is a perspective view showing a cross section of the pillar terminal. FIG 2A is a cross-sectional view showing an example that the pillar terminal is mounted as a component of a switching device, and FIG 2B is a cross-sectional view showing a state where the switching device is closed. FIG 3 is a flow chart showing a manufacturing method of the pillar terminal. FIG 4A is a cross-sectional perspective view in a state where a punch is introduced when the pillar terminal is manufactured, and FIG 4B is a cross-sectional perspective view in a state where a conductor having the electric contact is clinched when the pillar terminal is manufactured. FIG 5A is a cross-sectional perspective view showing a state after the clinching when the pillar terminal is manufactured, and FIG 5B is a cross-sectional perspective view after the manufacturing of the pillar terminal. FIG 6A is a cross-sectional perspective view in a state where a punch is introduced when a modification of the pillar terminal is manufactured, FIG 6B is a cross-sectional perspective view in a state where the conductor is clinched when the modification of the pillar terminal is manufactured, and FIG 6C is a cross-sectional perspective view showing an end of the conductor extended by the clinching. FIG 7A is a cross-sectional perspective view in a state where a press plate and the punch are introduced when another modification of the pillar terminal is manufactured, and FIG 7B is another cross-sectional view showing the state of FIG 7A. FIG 8A is a cross-sectional view in a state where the conductor is clinched when the modification of the pillar terminal is manufactured, and FIG 8B is a cross- sectional view showing a state where the press plate and the punch are removed from the state of FIG 8 A. FIG 9A is a cross-sectional perspective view showing the end of the conductor extended by the clinching, and FIG 9B is a cross-sectional perspective view showing the end of the conductor extended by the clinching in another modification of the pillar terminal. FIG 10A is a cross-sectional perspective view in a state where the punch is introduced when another modification of the pillar terminal is manufactured, FIG 10B is a perspective view showing the vicinity of a through hole of a terminal frame of the modification, and FIG 10C is a perspective view showing a cross section in the vicinity of the conductor of the modification. FIG 11A is a cross-sectional perspective view showing another modification of the pillar terminal in a state where the terminal frame and a substrate are separated, and FIG 11B is a cross-sectional perspective view in a state where the punch is introduced when the modification is manufactured. FIG 12 is a perspective view showing a cross section around the conductor of the modification. FIG 13A is a cross-sectional perspective view showing another modification of the pillar terminal in a state where the terminal frame and the substrate are separated, FIG 13B is a perspective view showing projections in the terminal frame of the modification, and FIG 13C is a cross-sectional perspective view of the modification. FIG 14A is a cross-sectional perspective view showing another modification of the pillar terminal, and FIG 14C is a cross-sectional view of the modification to which an electric wire is electrically connected. FIG 15A is a cross-sectional perspective view showing another modification of the pillar terminal, and FIG 15C is a cross-sectional view of the modification to which an electric wire is electrically connected. FIGS. 16A, 16B and 16C are cross-sectional views showing a clinching step for another modification of the pillar terminal in order, and FIG 16D is a cross- sectional view of the modification to which an electric wire is electrically connected. FIGS. 17A, 17B and 17C are cross-sectional views showing the clinching step for another modification of the pillar terminal in order, and FIG 17D is a cross- sectional view of the modification to which an electric wire is electrically connected. FIG 18A is a cross-sectional perspective view of another modification of the pillar terminal seen from the screw hole side, and FIG 18B is a perspective view of the modification seen from the electric contact side. FIG 19 is a cross-sectional view showing an example wherein the modification is mounted as a component of a switching device. Description of Embodiments [0017] Hereafter, a pillar terminal and its manufacturing method according to an embodiment of the present invention are described with reference to drawings. FIGS. 1 and 2 show a pillar terminal 1. As shown in FIGS. 1A, 1B and 1C, the pillar terminal 1 is equipped with a terminal frame 2 of a hollow cylindrical shape, a conductor 4 having a head for an electric contact 4a of a switching device 5 (shown in FIG. 2A), and a terminal screw 20. The pillar terminal 1 is mounted on the switching device 5. The terminal frame 2 is fixed integrally to a substrate 3 by clinching the conductor 4 having a rivet-like shape. The pillar terminal 1 fixes an electric wire 10 (shown in FIG 2A) inserted into the terminal frame 2 with the terminal screw 20. The terminal frame 2 is an iron-made frame having two surfaces facing mutually; the one of the surfaces has a screw hole 2a into which the terminal screw 20 is inserted; the other surface, facing the screw hole 2a, has a through hole 2b. The conductor 4 has a head at one end used as an electric contact 4a. The other end 4b of the conductor 4 opposite to the electric contact 4a is inserted into a through hole 3 a in the substrate 3 and also the through hole 2b from the outside of the terminal frame 2 so that it protrudes from the through hole 2b and faces the inside of the terminal frame 2. The conductor 4 is fixed to the terminal frame 2 by clinching the protruding end 4b of the conductor 4 flat so that the conductor 4 cannot move and the end 4b is used as an electric terminal. Since the conductor 4 has the electric contact 4a, the conductor 4 can be called a conductor for a contact or a contact conductor, and it is also a conductor for clinching fixation use and a conductor for electric wire connecting use. The pillar terminal 1 connects an electric wire 10 to the end 4b of the clinched and fixed conductor electrically by pressing the electric wire inserted in the terminal frame 2 against the end 4b using the terminal screw 20 screwed into the screw hole 20, and thereby, electrically connects the electric wire to the electric contact 4a. [0018] The terminal frame 2 can be manufactured by press molding or bending, for example using a cold rolled steel or a steel strip (SPCC etc.). The sizes of the terminal frame 2 are, for example, 1 mm in thickness, 9 mm in length (cylinder length), 8.5 mm in frame height, and 6 mm in frame width, and the diameter of the through hole 2b is 1.6 mm. It is made, for example, by rolling a steel strip of 6 mm wide into a rectangular cylinder, where the portion of the screw hole 2a is additionally overlapped for a strengthened structure. The conductor 4 for the contact is made of copper material, for example, and has a constitution as a clinching component: a part for the electric contact 4a of a proper outside dimension functioning as a rivet head, and a under-head part of a size thinner than the outside diameter of the electric contact 4a (for example, under-head diameter 1.5 mm, length 4.0 mm). The clinching component, namely, the conductor 4 for the contact is preferably plated at least in a portion of the electric contact 4a with gold, for example. The substrate 3 is an insulator, and a molded part of resin or reinforced resin with stiffener can be used for it, for example. [0019] The pillar terminal 1 is used in combination with a switching device 5, as shown in FIGS. 2A and 2B. The switching device 5 is equipped with: a covering 50, a key 51 exposed from the covering 50, a coil spring 52 mounted inside the key 51, an operation piece 53 at the end of the spring 52, a lever 54 caring out seesaw movements by operation of the operation piece 53, and a supporting conductor 55 used as a fulcrum of the seesaw movements. The switching device 5 including these is provided in a space facing the front surface of the substrate 3 where the electric contact 4a is arranged. The pillar terminal 1 is mounted on the rear surface of the substrate 3 (fixed contact). The substrate 3 is equipped with a similar terminal frame 2 resembling the terminal frame 2 in addition to the terminal frame 2 of the pillar terminal 1. The lever 54 is equipped with an electric contact 5a (moving contact), and carries out seesaw movements so that the electric contact 5a may contact with or depart from the electric contact 4a on the substrate 3. The key 51 is pivoted by a not-shown rotating shaft, and tilts freely according to on-off operation of the switch as shown by the arrow head R. The rotating shaft is fixed to the substrate 3. The supporting conductor 55 is arranged on the same front surface of the substrate 3 where the electric contact 4a is arranged, and mutually fixed to the substrate 3 and the terminal frame 2 by clinching a similar conductor 4 resembling the conductor 4 for the contact. The fixing between the supporting conductor 55, the substrate 3, and the terminal frame 2 may be done by screw-fixing, without using the clinching. In the state shown in FIG 2A, an electric wire 10 connected to the pillar terminal 1 is electrically connected to the electric contact 4a, and another electric wire 10 connected to another terminal frame 2 is electrically connected to the electric contact 5a through the conductor 4, the supporting conductor 55, and the lever 54, and these two electric wires 10 are in a non-conductive state mutually. On the contrary, in the state shown in FIG 2B, as a result of the pivoting of the lever 54 by operation of the key 51, the electric contact 5 a is electrically connected to the electric contact 4a, and the two electric wires 10 are in a conductive state mutually. [0020] As mentioned above, such as a copper terminal plate with a contact in a usual pillar terminal, used by inserting its part into a terminal frame, is unnecessary, because the pillar terminal 1 has a constitution that the electric contact 4a is directly fixed in the iron-made terminal frames 2 by the clinching. According to the pillar terminal 1, a special connection component (relaying conductor) of metal such as a copper plate which electrically connects the electric contact 4a and the terminal frame 2 is unnecessary, because the pillar terminal 1 has a constitution that the electric wire 10 is connected electrically to the end 4b of the conductor 4, and the conductor 4 has the electric contact 4a, and is fixed to the terminal frame 2 by the clinching. By these, a material cost can be reduced, and the number of parts count at the time for wire connection use becomes fewer. Since the wire can be electrically connected to the electrical contact only by fixing the wire to the pillar terminal 1, handling is easy, and the user-friendliness of the pillar terminal 1 becomes good. Furthermore, since the terminal frame 2 is made of iron, compared with the usual case where a terminal frame is made of copper, brass, etc., the material cost of the terminal frame 2 can be depressed and a cost reduction of the pillar terminal 1 can be realized, and miniaturization of the pillar terminal 1 can be achieved by its improved strength because of iron use. [0021] FIGS. 3 to 5 show a manufacturing method of the pillar terminal 1. As shown in FIG. 3, the manufacturing method of the pillar terminal 1 comprises a step (S1) for manufacturing the cylindrical terminal frame 2 which has the screw hole 2a and the through hole 2b, an inserting step (S2) for inserting the end of the columnar conductor 4 in the through hole 2b, and a clinching step (S3) for clinching the end of the conductor 4. In the step (S1), for example, a manufacturing method that rolls a steel strip into a rectangular cylinder as above mentioned can be used, and also a manufacturing method that performs followings in order can be used: making an iron circular pipe into square; forming the screw holes 2a and the through holes 2b with a predetermined interval in the square pipe; and cutting the pipe one by one based on a length of the terminal frame 2, etc. The step (S1) can include a process of plating for corrosion control etc. on the terminal frame 2. In the inserting step (S2), as shown in FIG 4A, the end of the conductor 4 is inserted into both the through hole 3a of the substrate 3 and the through hole 2b of the terminal frame 2 so that the end protrudes inside the terminal frame 2, where the end is opposite to the electric contact 4a in the conductor 4 and such conductor 4 is separately prepared in other step. The protruding end part 40 serves as a stock to be deformed by the clinching and therefore is referred to as a clinching stock 40. In the clinching step (S3), as shown in FIG 4B, a punch 6 for clinching use is introduced from the screw hole 2a, and the protruding clinching stock 40 of the conductor 4 prepared by the inserting step (S2) is clinched with the punch 6 to fix and unify the terminal frame 2 and the substrate 3 by the conductor 4 mutually. After that, as shown in FIG 5A, the punch 6 is taken out, and as shown in FIG 5B, the pillar terminal 1 is completed. The screw-thread formation by a tap in the screw hole 2a may be done at any time before and after the clinching step (S3). The clinching process is, for example, done using a punch 6 of outside diameter 3 mm and 400 kg of press load in the case that: the screw hole 2a is for a M4 screw (outside diameter of about 4 mm); the sizes of the under-head part of the contact conductor 4 are 1.5 mm in diameter and 4.0 mm in length; and the thickness of the substrate 3 is 1.5 mm, etc. In this case, for example, an end 4b extended is obtained in a size of outside diameter 2.61 mm. Moreover, the clinching step (S3) may be performed in one-step load operation, and also may be performed in multi-step load operation by making the punch 6 up and down, changing the press load and falling speed for every step, for example. [0022] FIGS. 6A, 6B and 6C show a modification of the pillar terminal 1 and its manufacturing method. In this pillar terminal 1, the end 4b of the conductor 4 extended by the clinching is formed more largely than the aperture of the screw hole 2a. Such an end 4b is formed, as shown in FIG 6A, using a conductor 4 having an enlarged volume in the clinching stock 40 to be deformed by the clinching. The volume enlargement is performed by enlarging the length or diameter of the clinching stock 40, for example. In the clinching step of the manufacturing method, as shown in FIG 6B, the end 4b of the conductor 4 extended by the clinching is made larger than the screw hole 2a by extruding the material of the conductor 4 into the outside of the punch 6. Here, using following notations for each size: a size D of the screw hole 2a, an outside diameter dl of the punch 6, an outside diameter d2 of the clinching stock 40 of the conductor 4, and an extended outside diameter d3 of the end 4b of the conductor 4, the relations between them are d2