Murata Manufacturing Co., Ltd.

Katsuhiro Onishi

Yukinori Ueda

Fumitoshi Masuda

Hideaki Tsukada

Kiminori Yamauchi

Yoshiyuki Nakatsu

Miroyuki Kishishita

In a resistance welding method and a resistance welding apparatus which prevent a decrease in bonding strength between a lead wire and a metal member due to a partially formed current flow path and which immediately removes a defective component from a manufacturing line, a plurality of second welding electrodes in contact with the metal member is provided so as to provide a plurality of current flow paths, and accordingly, to prevent an unevenly distributed current flow. The bonding strength is measured to determine whether it is satisfactory or not on the basis of currents flowing through the second welding electrodes. Also, the electronic component is fixed by the second welding electrodes after resistance welded.

Resistance welding method, resistance welding apparatus, and method for manufacturing electronic component

A variable resistor is constructed to reliably seal the space between a rotor and a substrate without insert-molding the substrate into a case, and to be produced at a very low cost. This variable resistor includes a hollow square-prism shaped case which is open at the top and the bottom, a substrate which is fitted into the lower opening of the case, and on the top surface of which a collector electrode and an arcuate resistor are provided, a rotor rotatably fitted into the upper opening of the case, a slider mounted on the bottom surface of the rotor and making sliding contact with the collector electrode and the resistor, an annular packing member disposed between the rotor and the substrate for sealing the space therebetween, terminals mounted on the substrate and electrically connected to the resistor and the collector electrode, and a metallic cover.

Variable resistor

A first rotor and a second rotor are prepared. The first rotor has a resistor and inner-peripheral and outer-peripheral electrodes respectively connected to end portions of this resistor. The second rotor has a resistor and inner-peripheral and outer-peripheral electrodes symmetrical with those of the first rotor, provided at a position corresponding to that obtained by rotating the first rotor about the axis of the first rotor by an angle of 180&deg; with respect to the first rotor. A variable resistor selectively uses either one of the first rotor and second rotor. This makes it possible to provide a variable resistor which requires few parts. Also, this makes it possible to reduce the kinds of bending operations that must be performed on the terminals.

A variable resistor includes at least two sliders fixed to the bottom of the concavity of a case, a rotor having an engaging portion for engagement with a tool, on the upper side thereof and rotatably received in the concavity of the case, a resistor substrate having a resistor and an electrode on the underside thereof, capable of being sliding-contacted with the slider, and attached to the underside of the rotor, a cover attached to the opening of the concavity of the case and held in such a manner that the rotor is restrained from rising and is rotatable, and an o ring performing the seal between the inner peripheral surface of the concavity of the case and the outer peripheral surface of the rotor. The rotor has a step portion formed in the outer peripheral surface on the underside thereof with the lower-side portion of the step portion having a short diameter. The resistor substrate is formed into a disk-shape having a diameter longer than that of the short diameter portion of the step portion of the rotor. The O ring is prevented from being released by fixing the resistor substrate to the underside of the rotor.

A variable resistor comprises a case, slide contactors, a rotor, a metal cover and lead terminals. Arms which are respectively provided at central portions of the slide contactors protrude from a bottom surface of a recess portion of the case and are each shaped like a comb. The arms are respectively contacted, at contact portions A, B and C, by electrodes and resistor of the rotor. Lead terminals are each circular in cross section and are respectively connected, at end surfaces of their lead wires, to the slide contactors. This makes it possible to obtain a variable resistor which is easy to manufacture, low in cost and excellent in reliability.

A first rotor and a second rotor are prepared. The first rotor has a resistor and inner-peripheral and outer-peripheral electrodes respectively connected to end portions of this resistor. The second rotor has a resistor and inner-peripheral and outer-peripheral electrodes symmetrical with those of the first rotor, provided at a position corresponding to that obtained by rotating the first rotor about the axis of the first rotor by an angle of 180.degree. with respect to the first rotor. A variable resistor selectively uses either one of the first rotor and second rotor. This makes it possible to provide a variable resistor which requires few parts. Also, this makes it possible to reduce the kinds of bending operations that must be performed on the terminals.

There is provided a variable resistor having a small number of parts and having an excellent heat releasing property. A rotor is rotatably contained in a concave portion of a case. The rotor has a resistive element provided on the bottom thereof and electrodes connected to both ends of the resistive element. Arms of sliders are provided on the bottom of the concave portion of the case in a sliding relationship with the respective electrodes and resistive element. A metal cover is disposed on the upper surface of the case in contact with the rotor.

Growing community of inventors

Sabae, Japan

Katsuhiro Onishi