Abstract: Disclosed herein is a vehicle including a variable intake pipe length device capable of adjusting the length of an intake pipe according to the condition of an engine, the intake pipe being provided in an intake passage for inducing air from an air cleaner box to an intake port of the engine, the intake pipe including a fixed funnel and a movable funnel movable relative to the fixed funnel by a driving force of an actuator, wherein the actuator is located inside of an envelope formed by the contour of the intake pipe.

Abstract: In an engine having a propeller mounted on one end of a crankshaft, the vibrations on an end portion of the crankshaft opposite to the propeller are effectively suppressed with a pair of vibration pendulum type weights arranged outside the crankcase whereby it is possible to easily perform a change of the vibration suppression structure in conformity with the property of the propeller.

Abstract: In an engine having a propeller mounted on one end of a crankshaft, the vibrations on an end portion of the crankshaft opposite to the propeller are effectively suppressed with a pair of vibration pendulum type weights arranged outside the crankcase whereby it is possible to easily perform a change of the vibration suppression structure in conformity with the property of the propeller.

Abstract: In a fuel injection type multicylinder engine, both the mounting of a camshaft angle sensor, which is operable in response to angular movement of a valve driving camshaft to detect a timing of injection of fuel injected from a fuel injection valve, on the engine and maintenance of the resulting engine are improved. A camshaft angle sensor S is operable in response to an angular movement of an exhaust-side valve driving camshaft and is mounted on the engine E at one side surface exposed from the lower portion of a frame F. Mounting of a cam pulsar of the angle sensor S from the side of the frame F and the maintenance is possible without being obstructed by the frame F.

Abstract: A transmission for a vehicle including first and second rotating shafts which are rotatable by the torque transmitted through a clutch. Each shaft includes several transmission gears. A resisting member can be disposed between a gear and its corresponding shaft, such that the resisting member reduces the difference in rotating speed between the first and second shafts. The resisting member serves to reduce shift shock and noise generated during shifting. Additional resisting members can be placed on either the first or second shaft in order to achieve reduced shift shock and noise.

Abstract: A gear having a high fatigue strength can be produced relatively inexpensively. The gear is produced by plastic working using a steel material containing C.ltoreq.0.01 wt %, Si.ltoreq.1 wt %, 0.05 wt %.ltoreq.Mn.ltoreq.0.5 wt %, P.ltoreq.0.1 wt %, S.ltoreq.0.03 wt %, 0.02 wt %.ltoreq.sol.Al.ltoreq.0.1 wt %, 0.8 wt %.ltoreq.Cu.ltoreq.1.7 wt %, and 0.02 wt %.ltoreq.Ti.ltoreq.0.1 wt %, the balance being Fe and inevitable elements. The gear is subjected to soft nitriding, serving as artificial aging, after a solution treatment. The resulting gear has a sufficiently deep, surface hardened layer. Further, the gear may be produced inexpensively since the simultaneous performance of the artificial aging and soft nitriding saves energy.

Abstract: An optical information recording and reproducing device is provided. The device includes a light source for emitting a light beam, a first diffraction element for splitting the light beam into at least three diffracted beams, an optical system guiding the diffracted beams to a recording medium, and a second diffraction element including at least one division line and a diffraction surface from which the diffracted beams are diffracted. The diffraction surface is divided into at least two regions by the division line or lines. One of the division lines is at a predetermined angle against the direction of a track on the recording medium, and the regions split each of the diffracted beams into at least two parts to diffract the parts in different directions. The device also includes an optical detecting element for detecting the light beams diffracted with the second diffraction element.

Abstract: The method of manufacturing an optical diffraction grating element of the present invention is characterized in adopting an ion beam made from a gas chemically reacting with a glass substrate when forming a diffraction grating having a serrated profile upon the glass substrate through an ion beam etching method. Also, when manufacturing an optical diffraction grating element that is divided into a plurality of regions whereon diffraction gratings having different diffraction angles with respect to an incident light are provided, the method of the present invention is characterized in forming slits into a resist film disposed upon a transparent substrate such as a glass substrate, in accordance with the patterns of the diffraction gratings, such that the width of the slits is constant irrespectively of the regions.

Abstract: The invention discloses an optical head device having a diffraction grating element divided into a plurality of diffraction gratings have a substantially equal diffraction angle, a substantially equal optical utilization efficiency, and different focal distances of first order diffracted lights, each of the first order diffracted lights being produced from a reflected light from the recording medium, at the respective diffraction gratings and a photodetector positioned at a mid-position between two focal points produced when there occurs no focusing error, the photo-detecting means having a plurality of photo-detecting parts juxtaposed in a direction substantially orthogonal to an average diffracting direction of the diffraction grating element. The above arrangement enables to produce a small size optical head device and improve the detecting of focusing errors and tracking errors.

Abstract: A process for preparing blazed holograms suitable for mass-production which includes fabricating a glass or metal plate having a surface of serrated cross section, disposing the glass or metal plate in an injection mold to allow the surface of serrated cross section to constitute an inner surface of the mold. Then injecting an acrylic resin in molten form into the mold under a specific molding pressure, and removing a molded acrylic resin from the glass plate or metal plate to obtain an acrylic blazed hologram.