Abstract: A reliable hydrodynamic bearing having high rotational accuracy is offered. The hydrodynamic bearing for a small-sized motor is made of a special nonmagnetic steel material that is excellent in terms of machinability, wear resistance, and corrosion resistance. This special steel material contains 14.00% Cr, 8.00% Mn, 0.20% C, 2.00% Ni, 0.35% Si, and less than 0.05% P. This special steel material has high machinability and so machining accuracies such as surface roughness and squareness can be enhanced. Consequently, the rotational accuracy of the hydrodynamic bearing can be enhanced. This special steel material also has such a property that when pressure is applied to plastically deform it, the pressed surface hardens. Using this nature, the surfaces at which rotating and stationary parts of the bearing contact with each other are pressed. Thus, the surfaces are hardened. Hence, the wear resistance is improved.

Abstract: A bottle-type plastic container has a body and an opening at one end of the container that allows liquid content to be filled into the container and emptied therefrom. The body includes at least one body portion having a substantially regular polygonal cross-section defined by a plurality of generally flat walls. The generally flat walls of the body portion include flexible walls and less-flexible walls, which are arranged alternately to each other in a circumferential direction of the body portion. When the container is filled with liquid contents at a high temperature and subsequently cooled to room temperature, a resultant pressure drop within the container is absorbed by the walls, initially by a primary inward deflection of the flexible walls and subsequently by a secondary inward deflection of the less-flexible walls. As such, the plastic container is particularly suited for hot fill applications.

Abstract: A double sleeve type dynamic bearing comprises a fixed shaft having at least one end fixedly mountable to an apparatus in which the bearing is utilized, a rotary sleeve arranged coaxially with the fixed shaft so that a first fine gap is formed therebetween, a fixed sleeve arranged coaxially with the rotary sleeve so that a second fine gap is formed therebetween, and a lubrication oil filled in the fine gaps. The first fine gap and the second fine gap each have an open end exposed to air outside the bearing and an opposite end that is not exposed to the air, the opposite ends being in communication with each other. A holding member holds the fixed shaft and the fixed sleeve and is disposed adjacent to a lower end surface of the rotary sleeve to form a third fine gap between the holding member and the lower end surface of the rotary sleeve. The third fine gap is formed with a thrust dynamic pressure producing groove, and opposite ends of the first and second fine gaps meet each other through the third fine gap.

Abstract: A method for lubricating a part without leaving air bubbles includes the steps of assembling components so that an open end is formed for application of lubricating fluid and a fluid path is provided through which the lubricating fluid is to be circulated, introducing the lubricating fluid into the open end and applying a centrifugal force to the component by moving the component about a circular path so that the centrifugal force causes the lubricating fluid to be urged throughout the fluid path. The method is used in an embodiment to lubricate a dynamic pressure bearing having a gap between relatively moving parts. The gap has an open end into which the lubrication fluid is dripped and a closed end. During movement of the bearing about a circular path, the fluid is urged from the open end to the closed end.

Abstract: A bottle-type plastic container has a body and an opening at one end of the container that allows liquid content to be filled into the container and emptied therefrom. The body includes at least one body portion having a substantially regular polygonal cross-section defined by a plurality of generally flat walls. The generally flat walls of the body portion include flexible walls and less-flexible walls, which are arranged alternately to each other in a circumferential direction of the body portion. When the container is filled with liquid contents at a high temperature and subsequently cooled to room temperature, a resultant pressure drop within the container is absorbed by the walls, initially by a primary inward deflection of the flexible walls and subsequently by a secondary inward deflection of the less-flexible walls. As such, the plastic container is particularly suited for hot fill applications.

Abstract: A bottle-type plastic container has a barrel portion and an opening at one end region of the barrel, for allowing liquid contents to be charged into the container and discharged therefrom. The barrel portion has a generally polygonal cross-section defined by a plurality of substantially flat walls, and a plurality of part-cylindrical corner walls extending contiguously between the flat walls. The flat walls each has a shape that is deflected inwards as the liquid contents charged into the container at a high temperature is cooled, to absorb a pressure drop within the container. The corner walls each has a center line of curvature extending in parallel with a longitudinal axis of the container, and a radius of curvature that decreases as the pressure drop is absorbed by the flat walls.

Abstract: The present invention is a double sleeve type fluid dynamic pressure bearing, comprising a fixed shaft having respective ends to be fixed to a utilized apparatus; a rotary sleeve arranged to provide a first fine gap between an inner peripheral surface thereof and an outer peripheral surface of the fixed shaft, a fixed sleeve arranged to provide a second fine gap between an inner peripheral surface thereof and an outer peripheral surface of the rotary sleeve, a holder member arranged to cooperate with a lower end surface of the rotary sleeve to provide a third gap, and wherein the first fine gap and the second fine gap are formed with radial dynamic pressure producing grooves while the third fine gap is formed with a thrust dynamic pressure producing groove, the first, second and third fine gaps being filled with lubrication oil, the first fine gap and the second fine gap having one ends made as opening ends contacting with the air and the other ends made as closed ends communicated with each other through the

Abstract: A fuel tank venting system for a vehicle comprises first and second vent passages connected to the fuel tank, and a third vent passage connected to the fuel tank. The first to third vent passages each have one end thereof located in the fuel tank at an upper front location thereof, an upper rear location thereof, and an upper central location thereof, respectively. An anti-overcharging valve is arranged in the fuel tank and connected to the other end of the third vent passage. A first valve is connected to the one ends of the first and second vent passages, and a confluent vent passage extends from the first valve toward an internal combustion engine installed in the vehicle. A second valve is arranged across the confluent vent passage on one side of the first valve closer to the engine. The third vent passage has the other end thereof connected to the confluent vent passage at a location intermediate between the first valve and the second valve.

Abstract: A process for casting a pipe such as a delivery pipe with transversal holes, the pipe having an elongate longitudinal hole and at least one pair of transversal holes communicating with the longitudinal hole in a substantially normal direction thereto. The process comprises the steps of positioning a rod-like center pin for forming the longitudinal hole in a predetermined positional relation to a cavity formation surface of a casting die, positioning a pair of mandrel pins for forming the pair of transversal holes such that end faces thereof are in contact with side surfaces of the center pin, and charging molten metal into a die cavity after the center pin and the pair of mandrel pins have been positioned. The molten metal is charged under the condition that the center pin is prevented from deforming by the pair of mandrel pins.

Abstract: A method of casting a pipe having an axially elongate hole of which a front end is closed, comprises the steps of positioning a rod-like center pin for forming the blind hole in a predetermined positional relation to cavity defining surfaces of a die cavity, supporting the positioned center pin sidewise with a support pin to prevent positional deviation of the center pin, charging molten metal into the die cavity, retreating the support pin apart from the center pin, and replenishing a space formed by the retreat of the support pin with molten metal.

Abstract: A casting mold includes a cavity formed therein, and an auxiliary mold projecting into the cavity. The auxiliary mold forms a concave portion in a cast product, and it exhibits a thermal expansion coefficient being more than a thermal expansion coefficient exhibited by a molten metal to be charged into the cavity. Hence, the auxiliary mold greatly expands thermally during casting, and it keeps the expanded state during the solidification of the molten metal. Accordingly, the casting mold can prevent the casting defects resulting from the shrinkage cavities from arising in the resulting cast products. All in all, the casting mold can obviate to give the auxiliary mold a tapered configuration, and it can reduce the after-casting machining allowance to be provided in the resulting concave portion.

Abstract: In a method of vacuum casting molten metal sucked from a molten metal reservoir into a cavity held under a reduced pressure by opening a gate having been blocking the communication between the molten metal reservoir and the cavity, the trapping of gas and foreign matter in the cavity is effectively prevented. To this end, an accommodation space for accommodating gas and foreign matter is provided in the molten metal reservoir. The accommodation space is provided at a position from which the accommodated matter is not sucked into the cavity.

Abstract: In a vacuum casting method, a mold cavity is reduced in pressure to a vacuum, and when a gate is opened, a molten metal which has been raised to a molten metal retaining dome is charged into the cavity at a high speed. When a portion of a molten metal held in a molten metal holding furnace is raised to the molten metal retaining dome, an upper surface of the molten metal is moved downwardly and upwardly through at least one cycle in the molten metal retaining dome, or a swirl flow is generated in the molten metal in a stalk. Such a unique motion as the downward and upward motion or the swirl flow effectively operates to detach solid metal pieces from an inside surface of the molten metal retaining dome or the stalk to push them to an upper portion of the molten metal. As a result, the detached metal pieces are prevented from being charged into the mold cavity to thereby cause defects in a cast product.

Abstract: A vacuum casting apparatus of the type wherein a gate mechanism (12 and 10) is closed to form a seal. The interior of a cavity (6) is evacuated by a vacuum pump. The side of the gate mechanism (12 and 10) opposite to the cavity is filled with molten metal. The gate mechanism includes a ring-shaped groove (10e) having a V-shaped cross section positioned on the side opposite to the cavity which extends towards the sealing portion of the gate mechanism (12 and 10). With this arrangement, the molten metal in passage (8) fills the ring-shaped groove (10e) and enters the small clearance which exists in the sealing portion of the gate mechanism. The molten metal solidifies both within the ring-shaped groove (10) and this small clearance formed in the sealing portion. The resulting solidified metal piece has generally a ring shape that can be readily peeled off from the gate mechanism (12 and 10) following die release.

Abstract: A method of casting including the steps of closing gates with a counter tip after lower and upper molds heated to a predetermined temperature have been clamped, pouring melt into a sleeve in which a plunger tip is lifted a predetermined distance, lowering the plunger tip while displacing the counter tip to a predetermined position to open the gates, which are formed such that the ratio of the volume of products to the cross-sectional area of the gates is 20-40 (i.e. the volume of products/(CM.sup.3) cross-sectional area of gates (CM.sup.2)=20-40), to allow the melt to flow into cavities via the gates by the force of gravity alone with the plunger tip reaching the upper surface of the melt the moment a percentage of the melt placed in the cavities has reached a value between 30 and 70%, and pressure-filling the cavities with the melt by the plunger tip with the melt passing through the gates at 0.4-0.8 m/sec.