Abstract: A shift device includes: a motor drive circuit; a motor driver unit for driving the motor drive circuit; a control unit that controls the motor driver unit; a motor power supply path; a system power supply path; and a buck-boost unit that converts electric power supplied from the system power supply path to a predetermined voltage and outputs the voltage. Electric power is supplied to the control unit via the buck-boost unit, and either the electric power from the motor power supply path or the electric power from the system power supply path is supplied to the motor driver unit based on a voltage.

Abstract: A method of producing a coil spring including a part of high hardness and a softening part of lower hardness than the part, the method including: a step of heating a wire rod; a step of forming the wire rod heated into a spiral shape; a step of quenching and tempering the wire rod spirally formed; and a step of carrying out electrical heating to a part that is the softening part on the wire rod quenched and tempered, with a pair of electrodes applied to both faces of the softening part.

Abstract: This coil spring has a part of high hardness and a part of lower hardness than the part. Also, it is preferable that the hardness of the part that comes into contact with other members is lower than the hardness of the part other than the part that comes into contact with the other members. Moreover, it is preferable that the hardness of an end turn part of the coil spring is lower than the hardness of the part other than the end turn part. Furthermore, it is preferable that the hardness of the part that comes into contact with a receiving member adapted to receive the end turn part of the coil spring is lower than the hardness of the part other than the part that comes into contact with the receiving member.

Abstract: To provide a lighting device which is enabled to light a lamp of an incandescent bulb or the like in high luminance by a battery to be amounted on a vehicle. A lighting source lighting device 10 includes: an inverter 11 for converting a direct current from a vehicle-mounted battery 15 into an alternating current; and current adding means 13 for adding the direct current from the vehicle-mounted battery 15 and alternating current generated by the inverter 11, to supply a light source 14, such as a head lamp, with the added electric current. In this construction, the light source 14 is driven with the electric current containing the direct current and alternating current superimposed thereon so that the light source luminance microscopically changes with the period of the alternating current.

Abstract: The present invention provides a silicon nitride sintered body having characteristics such as excellent wear resistance, a method for manufacturing the sintered body, and a cutting insert formed thereof. The silicon nitride sintered body is formed of a polycrystalline sintered body of predominantly &bgr;-Si3N4, wherein the oxygen content is 1.2-1.5 wt. %. The method for manufacturing the silicon nitride sintered body includes the following steps: adding an organic binder to a composition containing silicon nitride as an essential component and exhibiting a theoretical oxygen content of 2.0-3.0 wt. %; heating to remove the binder; introducing an oxygen-containing gas so as to control the carbon content to 0.10-0.60 wt. %; and sintering a resultant compact in an nitrogen atmosphere to control the oxygen content to 1.2-1.5 wt. %. The cutting insert of the present invention has excellent wear resistance.

Abstract: A cermet tool is made up of a binder metallic phase forming component of Ni or Ni and Co and a hard phase including a hard phase metallic element component of Ti as its main part and one or more of an additional metallic compound selected from V, Cr, Zr, Nb, Mo, Hf, Ta and W. A surface coating layer is formed on the surface of the cermet. The surface coating layer satisfies at least one of the appearance lightness Vs of 6 or more and the saturation Cs of 4 or more. When wear of a tip of a cermet tool proceeds, that part changes its color to a blackish tone (corresponding, for example, to Vs of from 4 to 1 and Cs of from N to 3). By adjusting the appearance lightness and the saturation of the surface coating layer to the ranges described above, a worn part and a non-worn part are easily distinguished by the naked eyes based on the difference in lightness or hue. As a result, distinction of a spent tool and judgement of the life of the tool can be easily conducted.

Abstract: A cermet tool and process for making the same is disclosed. The cermet tool has a surface coating layer which exhibits a function equivalent to or higher than a hard coating layer of a conventional cermet tool. The tool is economical to produce since no additional step such as a gas phase film forming method is necessary for the formation of the surface coating layer. The surface coating layer has essentially the same hard phase composition as the interior main body part, but the weight content of the binder metallic phase metallic element component is smaller than the average weight content of the binder metallic phase metallic element component through out the cermet (or the weight content in the main body part). This surface coating layer is formed on the surface outermost part of the cermet body. Because the surface coating layer has a content of the binder metallic phase smaller than that in the main body part, it has a hardness higher than the main body part.

Abstract: The present invention provides a silicon nitride sintered body having characteristics such as excellent wear resistance, a method for manufacturing the sintered body, and a cutting insert formed thereof. The silicon nitride sintered body is formed of a polycrystalline sintered body of predominantly .beta.-Si.sub.3 N.sub.4, wherein the oxygen content is 1.2-1.5 wt. %. The method for manufacturing the silicon nitride sintered body includes the following steps: adding an organic binder to a composition containing silicon nitride as an essential component and exhibiting a theoretical oxygen content of 2.0-3.0 wt. %; heating to remove the binder; introducing an oxygen-containing gas so as to control the carbon content to 0.10-0.60 wt. %; and sintering a resultant compact in an nitrogen atmosphere to control the oxygen content to 1.2-1.5 wt. %. The cutting insert of the present invention has excellent wear resistance.

Abstract: Titanium carbo-nitride complex silicon nitride tool is composed mainly of titanium carbo-nitride and silicon nitride and contains 10 to 56 wt % of Ti, 11.6 to 51 wt % of Si and 1 to 21 wt % in total of one or two or more of Ce, Y, Yb and Dy. The tool is mainly composed of Si.sub.3 N.sub.4 superior in both strength and resistance against thermal shock and TiCN superior in the effect of suppressing reactivity of Si.sub.3 N.sub.4 with Fe and exhibiting high hardness. By using oxides CeO.sub.2, Y.sub.2 O.sub.3, Yb.sub.2 O.sub.3 and Dy.sub.2 O.sub.3 as sintering aid so that the sum of the amounts of Ce, Y, Yb and Dy will be in the above range, both the resistance against flank notch (wear) of the end edge and resistance against thermal shock are improved resulting in improved durability as compared to the conventional silicon nitride cutting tool.

Abstract: Sintered silicon nitride articles for cutting tools and the like, having a high relative density, excellent wear resistance and nicking, particularly at high temperatures, and a method for preparing such articles are disclosed. The articles are made by mixing 0.25 to 3.0 vol % of magnesium oxide powder and 0.3 to 2.0 vol % of ytterbium oxide with silicon nitride starting materials, then crushing and mixing, optionally with 1.0%-vol. or less, preferably 0.5%-vol. or more of aluminum oxide powder and adding an organic binder. The article is formed using a metal press to a shape for usage as SNGN120408 tools. The sintered silicon nitride articles for tools are obtained by degasing the shaped articles, subjecting them to a primary firing at 1700 to 1900.degree. C. and 0.3 to 1.0 MPa temperature and pressure, and following with a secondary firing at a temperature which is substantially lower than the primary firing temperature, at a pressure of 100 MPa or greater.