Abstract: A spark plug includes a center electrode, an insulator, a metallic shell, and a seal member for providing a seal between the insulator and the metallic shell. The insulator includes a first portion, a second portion located axially forward of the first portion and being smaller than the first portion, and an insulator first-diameter-reducing-portion whose outside diameter reduces forward and which connects the first portion and the second portion. The metallic shell includes a protrusion that includes a metallic shell diameter-reducing-portion whose inside diameter reduces forward. The seal member is disposed between the insulator first-diameter-reducing-portion and the metallic shell diameter-reducing-portion.

Abstract: A spark plug includes an insulator including an axial hole and having an outer periphery with a tapered outer face; a metal shell having a thread portion and a tapered inner face; and a circular packing sandwiched between the tapered outer face of the insulator and the tapered inner face of the metal shell. On at least one cross section including the axis, (A/B)?3.1, B?0.25, and (A+B)?2.0 are satisfied, where A represents a length of (a difference between an effective diameter of the thread portion and an inner diameter at a rear end of the tapered inner face)/2, and B represents a length of (a difference between the inner diameter at the rear end of the tapered inner face and an inner diameter at a front end of the tapered inner face)/2.

Abstract: A spark plug includes: a rod-shaped center electrode extending in an axial direction; an insulator including a shaft hole that holds the center electrode inside of the shaft hole; a metal shell surrounding and holding a part of the insulator; and a ground electrode including a base end welded to the metal shell. The metal shell and the ground electrode are joined via a fusion portion formed by welding the ground electrode and the metal shell together. When the smallest thickness of the fusion portion in the axial direction is A, when, in a cross section that includes a center line of the ground electrode and is parallel to the axis, a length of a ground-electrode-side melted boundary formed between the fusion portion and the ground electrode is B, and when the ground electrode thickness is C, conditions of A?0.2 mm and B>C are satisfied.

Abstract: A drive state control apparatus is applied to a vehicle which has not only a transfer including a multi-disc clutch mechanism but also a changeover mechanism interposed in an axle and which can be switched between 2WD and 4WD. When a 2WD-to-4WD changeover condition is satisfied, the multi-disc clutch is immediately switched from a “decoupled state” to a “coupled state.” Meanwhile, a connecting operation of the changeover mechanism is started upon establishment of a state in which left and right rear wheels have no acceleration slippage, and a state in which rotational speeds of first and second axles on opposite sides of the changeover mechanism are approximately equal to each other. In addition, in the case where the left and right rear wheels have acceleration slippage after the 2WD-to-4WD changeover condition has been satisfied, an E/G output reduction control is executed. Thus, the connecting operation can be performed smoothly.

Abstract: A four-wheel-drive vehicle includes a clutch that is able to allow and interrupt transmission of driving force to a propeller shaft, and a traction control unit that controls at least one of the driving force generated by an engine and braking force applied to right and left front wheels to suppress a slip of the right and left front wheels. When the drive mode is switched from a two-wheel-drive mode to a four-wheel-drive mode, if the relative rotational speed between a first rotary member and a second rotary member constituting a clutch is equal to or higher than a predetermined value, an ECU outputs a control command signal for suppressing the slip of the right and left front wheels to the traction control unit.

Abstract: A spark plug includes a ceramic insulator extending in the direction of an axis (CL1) and a metallic shell provided around the ceramic insulator. Talc is pressed charged between the ceramic insulator and the metallic shell and a crimp portion is formed for fixing the metallic shell and the ceramic insulator while the metallic shell having the ceramic insulator inserted thereinto is supported by a tubular receiving member. The receiving member is made movable in relation to a pressing jig in its radial direction. Thus, at the time of pressing of the talc, etc., the eccentricity between the center axis (CL2), (CL3) of the pressing jig and the axis (CL1) in the radial direction can be reduced, whereby the misalignment between the axis (CL1) and the center axis of the metallic shell or the like assembly error can be suppressed.

Abstract: A spark plug and manufacturing method. The spark plug (1) includes a metallic shell (3) extending along an axis CL1, a ceramic insulator (2), a center electrode (5), and a ground electrode (27) having a base end portion joined to a front end face (26) of the metallic shell (3). The method includes assembling the metallic shell (3) and a center electrode assembly (41); and joining the ground electrode (27) to the front end face (26). The distance between a reference plane SP perpendicular to the axis CL1 and the front end face (26) as measured along the axis CL1 varies in the circumferential direction. In the joining step, the position of the distal end portion of the ground electrode (27) relative to the front end portion of the center electrode assembly (41) along the axis CL1 is adjusted by changing the region of the front end face (26) to which the ground electrode (27) is joined.

Abstract: An optical modulator module includes an optical modulator including an optical waveguide which conducts an inputted optical signal, and m modulator regions on the optical waveguide; and m discrete driving circuits serially connected to one another. The discrete driving circuits include a driving circuit which outputs a signal obtained from a digital input signal with a synchronization signal to one of the modulator regions, and a phase shifting circuit which outputs a signal resulting from giving a delay to a signal branched from the synchronization signal. A discrete driving circuit receives the signal outputted from the phase shifting circuit. Each of the modulator regions includes modulation electrodes, an electric field caused by a modulation electric signal applied to each of the modulation electrodes penetrates by a penetration length d, and every two adjacent modulation electrodes has a distance Lgap given by Lgap=2d.

Abstract: Waveguide-type optical phase modulator regions of a linear accelerator-type column electrode structure MZ optical modulator are arranged on a semiconductor optical waveguide. A transmission line of an integrated circuit receives a clock signal through a buffer circuit disposed on an input side. Clock terminators are connected between an end of the transmission line and clock terminator power supply electrodes (VCa, VCb). Individual driving circuits receive the clock signal from different positions of the transmission line. An i (1?i?m, i is an integer)-th individual driving circuit counted from the input side outputs a signal obtained by amplifying a digital input signal in synchronization with the clock signal to an i-th waveguide-type optical phase modulator region.

Abstract: The present invention provides a compact, broad-band, and low-drive-voltage optical modulator module capable of generating any multilevel optical modulation. The optical modulator module according to an exemplary aspect of the present invention includes a digital segmented electrode structure optical modulator and m individual driving circuits. The digital segmented electrode structure optical modulator includes semiconductor optical waveguides and at least m waveguide-type optical phase modulator regions. An i-th individual driving circuit includes a driving circuit and a phase shift circuit. The driving circuit amplifies a digital input signal in synchronization with a clock signal and outputs the signal to an i-th waveguide-type optical phase modulator region. The phase shift circuit applies a delay to a signal branched from the clock signal. A j-th individual driving circuit receives an output signal from the phase shift circuit of a (j?1)-th individual driving circuit as a clock signal.

Abstract: A spark plug includes a tubular metallic shell extending in the direction of an axis and having a tool engagement portion formed through extrusion. The tool engagement portion has a 12-point shape which is a sectional shape taken orthogonally to the axis and has a plurality of protrusions and recesses provided alternately. As viewed in a section taken orthogonally to the axis, when D (mm) represents the diameter of a circle which passes radially through the outermost positions on the protrusions, and d (mm) represents the diameter of a circle which passes radially through the innermost positions on the recesses, the relational expression 0.45?(D?d)/2?0.75 is satisfied. The spark plug can provide a more reliable restraint on the slippage of a tool at the time of mounting and enables the tool engagement portion to be reliably formed so as to form a desired shape.

Abstract: A spark plug includes a ceramic insulator having an axial bore extending in the direction of an axis (CL1) and a terminal electrode inserted into the axial bore. The terminal electrode includes a rodlike leg portion inserted into the a rear end portion of the axial bore and a head portion exposed at the rear end of the ceramic insulator. A front end subportion of the leg portion of the terminal electrode is fixed to the ceramic insulator, and the leg portion has a length of 35 mm or more along the axis (CL1). The center of gravity of the terminal electrode is located in the interior of the ceramic insulator.

Abstract: In a spark plug, at least one of a center electrode and a ground electrode has a cover portion and a core portion having a different thermal expansion coefficient. The core portion has a concave portion and a convex portion formed at a front end thereof. The convex portion is such that, in a cross section passing through a barycenter of a front surface of the electrode and also passing through the convex portion, an area of the convex portion delimited by a line perpendicular to a bisector of the convex portion and passing through a point 0.2 mm shifted from a front end of the convex portion in the direction of the bisector is smaller than an area of a triangle formed by connecting the front end of the convex portion and intersections of the line perpendicular to the bisector and a contour of the convex portion.

Abstract: A spark plug includes a ceramic insulator having a tapered rear end stepped portion whose diameter decreases from front to rear and a metal shell having a crimp portion which crimps the rear end stepped portion from the rear end. An area defined by an outer edge of the rear end stepped portion and an inner edge of the crimp portion is 5-25 mm2 when the spark plug is projected on a plane perpendicular to an axial line. An angle formed by a tapered surface of the rear end stepped portion and a plane perpendicular to the axial line is 20-60 degrees. A distance along the axial line from a front end of a proximal portion of the crimp portion to a frontmost position of a contact portion between an inner surface of the crimp and the rear end stepped portion is 0.4-1.8 mm.

Abstract: A method for manufacturing a spark plug includes an assembling step of assembling an insulator into a metallic shell by insertion of the insulator into the metallic shell from an axially rear end opening portion of the metallic shell. The assembling step includes a displacement restricting step of restricting a relative positional displacement between the metallic shell and the insulator in a radial direction intersecting with the axial direction so as to reduce eccentricity between the axis of the metallic shell and the axis of the insulator to a predetermined value or less, while allowing a relative positional displacement between the metallic shell and the insulator in the axial direction. In the assembling step, whether or not the insulator is cracked in the assembling step is judged by detecting acoustic emission from the insulator.

Abstract: A four-wheel-drive vehicle includes a clutch that is able to allow and interrupt transmission of driving force to a propeller shaft, and a traction control unit that controls at least one of the driving force generated by an engine and braking force applied to right and left front wheels to suppress a slip of the right and left front wheels. When the drive mode is switched from a two-wheel-drive mode to a four-wheel-drive mode, if the relative rotational speed between a first rotary member and a second rotary member constituting a clutch is equal to or higher than a predetermined value, an ECU outputs a control command signal for suppressing the slip of the right and left front wheels to the traction control unit.

Abstract: A spark plug includes a center electrode extending along an axial line, a ground electrode, and a noble metal tip. A center axis of the noble metal tip is displaced from a center axis of the ground electrode toward a base-end side in the axial line. The ground electrode includes an outer layer and an inner layer, and a distal end of the inner layer is closer to the axial line than a base end of the ground electrode. An overlap area between the inner layer and the noble metal tip occupies a ratio of 25% or more in a projective plane defined by projecting, along the center axis, a plane of the ground electrode viewed from a distal-end face on a cross section of the ground electrode in which a maximum cross-sectional area of the inner layer is achieved, among cross sections orthogonal to the center axis.

Abstract: There is provided manufacturing method of a spark plug that includes a center electrode and a ground electrode with a discharge gap left therebetween. At least one of the center electrode and the ground electrode has an electrode body containing a base metal and a noble metal tip welded to the electrode body. The spark plug manufacturing method includes a laser welding step for welding the noble metal tip and the electrode body by placing the noble metal tip at a given position on the electrode body, irradiating a pulsed laser onto the noble metal tip and the electrode body and thereby sequentially forming welding spots corresponding to pulses of the laser in a circumferential direction of the noble metal tip, wherein at least one of the laser pulses is an initially increasing type laser pulse having a laser intensity waveform in which a laser intensity increases with time during a predetermined initial period from a pulse start time.

Abstract: Disclosed is a spark plug having an insulator with good breakage resistance. A spark plug 1 contains a ceramic insulator 2, a plate packing 22 and a metal shell 3. The ceramic insulator 2 has, on an outer circumferential surface thereof, a step portion 14, a leg portion 13 and a curved surface portion 31 between the step portion 14 and the leg portion 13. The metal shell 3 has, on an inner circumferential surface thereof, a taper portion 21. The ceramic insulator 2 is fixed in the metal shell 3 with the step portion 14 retained on the taper portion 21 via the plate packing 22. Herein, 50% or more of an inner circumferential edge portion IP of the plate packing 22 is in contact with a part of the ceramic insulator 2 located front of a middle region CP of the curved surface portion 31.

Abstract: An on-demand-type drive state control apparatus for a vehicle is provided. In the case where acceleration slippage occurs at drive wheels (rear wheels) of a vehicle when a drive system is in a two-wheel drive state, the drive system is switched from the two-wheel drive state to a four-wheel drive state. That is, the maximum transmittable torque of a multi-disc clutch mechanism increases from “0” to a predetermined value. In the four-wheel drive state, the maximum transmittable torque decreases stepwise from the present value by a predetermined value every time the vehicle travels over a predetermined distance in a state in which none of the wheels cause acceleration slippages. That is, the clutch drive current supplied to the multi-disc clutch mechanism decreases gradually (stepwise or in a plurality of steps), and the drive torque distributed to the front wheels (rear wheels) decreases (increases) gradually.