Abstract: In an outboard engine system, an inertia force a generated longitudinally by a piston 14 is countervailed by an inertia force b generated by a crankshaft 15, and inertia forces c and d subsidiarily laterally generated vibrate a body of the outboard engine system laterally about a phantom center point C of vibration. At this time, an elastomeric member 74 resiliently supporting the system body on a hull has a rigidity in a tangent direction (in the direction of L3) about the phantom center point C of vibration, which is set to be lower than a rigidity in a radial direction (in the direction of L2) about the phantom center point C of vibration. Therefore, the lateral vibration is reduced effectively due to the lower rigidity of the elastomeric member 74. Thrusts e and f generated by a propeller and acting in a longitudinal direction (in the direction of L1) are transmitted to the hull through the elastomeric member 74.

Abstract: The present invention provides a numerical control apparatus for a machine tool, which corrects an axial displacement of a main spindle caused due to a change in preload level and occurring according to the rotation speed of the main spindle. The numerical control apparatus (3) comprises: a numerical control section (6) for numerically controlling the movement of a spindle head (2) and for outputting a rotation command; a spindle control section (7) for controlling the rotation of a main spindle (5); a preload change control section (8) for changing the level of a preload applied to bearings (36, 37); and a correcting section (9) for outputting correction data for correction of an axial displacement of the main spindle (5) caused due to a change in the preload level and occurring according to the rotation speed of the main spindle (5) to the numerical control section (6) on the basis of the rotation command.

Abstract: An outboard engine system includes a casing having a driving-force transmitting device provided therein, and an engine for transmitting power through the driving-force transmitting device to a propeller. The casing and the engine are carried on a hull for tilting-up movement. An engine cover made of a synthetic resin covers at least an upper portion of the engine, and an undercover comprises a pair of cover halves made of a synthetic resin and connected to each other to cover at least a lower portion of the engine from opposite sides. The undercover is detachably connected at its upper end to a lower end of the engine cover and fixed to an upper portion of the casing. In such outboard engine system, the undercover is detachably fixed at its upper portion to a body of the engine. Thus, the undercover can be supported so as to give an impression that the engine cover and the undercover are rigid during a tilting-up operation.

Abstract: The present invention provides a numerical control apparatus for a machine tool, which corrects an axial displacement of a main spindle caused due to a change in preload level and occurring according to the rotation speed of the main spindle. The numerical control apparatus (3) comprises: a numerical control section (6) for numerically controlling the movement of a spindle head (2) and for outputting a rotation command; a spindle control section (7) for controlling the rotation of a main spindle (5); a preload change control section (8) for changing the level of a preload applied to bearings (36,37); and a correcting section (9) for outputting correction data for correction of an axial displacement of the main spindle (5) caused due to a change in the preload level and occurring according to the rotation speed of the main spindle (5) to the numerical control section (6) on the basis of the rotation command.

Abstract: The present invention relates to a method and apparatus for calculating a correction value for thermal displacement whereby accurate correction values for thermal displacement can be calculated even when the rotation of the main spindle is restarted after interruption thereof, wherein the apparatus for calculating the correction value for thermal displacement comprises temperature measuring means 2 and 3 for measuring the temperature in the vicinity of the main spindle 15, thermal displacement amount estimating means 5 for estimating an amount of thermal displacement of the main spindle 15 on the basis of the measured temperature and a predetermined thermal displacement amount calculation expression, correction value calculating means 7 for calculating the correction value, and adjusting displacement amount calculating means 6, which estimates an amount of displacement delay in re-rotation caused by the interruption of the rotation of the main spindle 15, and calculates an adjusting displacement amount on the

Abstract: An outboard engine system includes a casing having a driving-force transmitting device provided therein, and an engine for transmitting power through the driving-force transmitting device to a propeller. The casing and the engine are carried on a hull for tilting-up movement. An engine cover made of a synthetic resin covers at least an upper portion of the engine, and an undercover comprises a pair of cover halves made of a synthetic resin and connected to each other to cover at least a lower portion of the engine from opposite sides. The undercover is detachably connected at its upper end to a lower end of the engine cover and fixed to an upper portion of the casing. In such outboard engine system, the undercover is detachably fixed at its upper portion to a body of the engine. Thus, the undercover can be supported so as to give an impression that the engine cover and the undercover are rigid during a tilting-up operation.

Abstract: In an outboard marine drive, the engine is received in an under case, and is closed by both a fan cover and an engine cover so that the engine may be entirely covered by the engine cover jointly with the under case for a favorable aesthetic effect. However, the fan cover covers the engine closely in cooperation with the under case so that a narrow air passage is defined around the engine, and cooling air of high velocity can be continuously passed around the engine. Thus, according to the present invention, no part of the engine is exposed, but the fan cover surrounding the engine defines an appropriate gap around the engine for effectively guiding cooling air around the engine.

Abstract: In an outboard engine, a support member for supporting a drive shaft and an exhaust pipe within an extension case can be cooled by outside water pumped by utilizing the exhaust pressure from the engine. The inside of the extension case is divided, by the support member for supporting the drive shaft and the exhaust pipe, into an upper chamber communicating with the open air, and a lower chamber into which outside water is introduced, so that the exhaust gas from the exhaust pipe is discharged into the lower chamber. Both the upper and lower chambers are in communication with each other through a communication pipe. Thus, during operation of the engine, the support member and the depending members are cooled by the outside water forced up from the lower chamber through the communication pipe into the upper chamber.

Abstract: In an outboard marine drive, a tubular socket member is sealingly fitted into an opening formed on one side of the crankcase of the engine at a level corresponding to a normal engine lubricating oil level, and a transparent window member is sealingly fitted into an outer end of the tubular socket member. An engine cover covering the engine is provided with an opening aligned with the transparent window member so as to allow the level of lubricating oil in the crankcase to be inspected from outside the engine cover. The socket member may also be provided with an oil filler pipe bifurcating upwardly from the socket member at an oblique angle, and an oil drain pipe bifurcating downwardly from the socket member at an oblique angle so that filling and removing lubricating oil into and out of the crankcase of the engine can be easily accomplished without complicating the structure for managing engine lubricating oil.

Abstract: In an outboard marine drive including a vertically oriented engine, a disk member is attached to a lower end of the crankshaft of the engine, and the upper end of the drive shaft is disposed coaxially with respect to the crankshaft and at a prescribed distance from the disk member so that a direct coupling member and an centrifugal clutch device may be interchangeably installed between them. The disk member is provided with axial holes for either pivotally supporting clutch shoes or fixedly attaching the upper end of the direct coupling member. The lower end of the direct coupling member and the clutch drum of the centrifugal clutch device are provided with an identical coupling arrangement for coupling with an upper end of the drive shaft.

Abstract: In an outboard marine drive, a primary partition made of elastomeric material is provided in a lower part of the extension case, and a drive shaft and an exhaust pipe are sealingly passed through the primary partition. Thereby, the extension case is kept out of direct contact from the exhaust gas, and is therefore prevented from excessive heating. The exhaust pipe and the drive shaft typically have a large length, and it is advantageous to support them at parts thereof near a lower end thereof. The use of elastomeric material for the primary partition is particularly advantageous because it not only can favorably insulate heat but also can accommodate any positional errors in the exhaust pipe and the drive shaft relative to the extension case. When a secondary opening is formed in an upper part of the exhaust pipe to prevent excessive build up of exhaust back pressure when the engine is idling, a secondary partition may also be provided in an upper part of the extension case.

Abstract: A vibration-proof power take-off device for an engine includes a resilient support device for carrying the engine on a support, and a displacement absorbing joint for connecting an output shaft of the engine to a power take-off member. The displacement absorbing joint has a first joint member connected to the output shaft, a second joint member connected to the power take-off member, and a resilient member for resiliently interconnecting the joint members. The first joint member includes a first hub having radially projecting first transmitting fins and the second joint member includes a second hub concentrically surrounding the first hub and having radially projecting second transmitting fins. The intermediate member has intermediate fins opposed to the first and second fins in a rotational direction. Opposed surfaces of the intermediate fins and the first and second fins are interconnected through the resilient member.