An engine device having a flywheel housing (7) in which a flywheel that is rotated integrally with a crankshaft (5) is accommodated on one side portion (303) of a cylinder block (6), in which the cylinder block (6) is integrally formed with housing bracket portions (304) each protruding in a direction away from the crankshaft (5) from each of opposite side portions (301) of the cylinder block (6) extending along a crankshaft axial direction (300), the housing bracket portions (304) protruding from end portions of the opposite side portions (301) close to the one side portion (303). A space surrounded by the one side portion (301), the housing bracket portions (304), and the flywheel housing (7) constitutes a gear case (330) for accommodating therein a gear train.

An added inertia resonant system (12) for a power toothbrush (10) comprises a drive shaft (16), a drive system (22), and at least one inertial weight member (24). The drive shaft (16) has a principal axis (26) that defines a center of rotation. The drive system (22) imparts a reciprocating motion to the drive shaft (16) about the principal axis (26). The at least one inertial weight member (24) couples to the drive shaft (16) and comprises a planar material having a complex shape balanced along an x-, y- and z-axis to enable the drive system (22) to achieve low power, high amplitude motion of the drive shaft (16) when placed under user loading. A method for providing added inertia in a resonant system for a power toothbrush is also disclosed.

A multiple-keyed crankshaft and flywheel provides for different ignition timing options for an internal combustion engine. The crankshaft of the engine includes multiple keyways set at designated angular displacements of the crankshaft that correspond with keyways on a flywheel for providing different timing options for the engine. The flywheel may be mounted to the crankshaft by aligning one of the keyways of the flywheel to one of the keyways of the crankshaft related to a particular ignition timing selection.

A flexible flywheel includes: a shaft fastening portion fixed to an end portion of an engine crankshaft; an annular inertia ring provided around the shaft fastening portion; a plurality of elastic spoke portions which extend in the radial direction between the shaft fastening portion and the inertia ring and connect the shaft fastening part and the inertia ring to each other, and that absorb vibration acting on the crankshaft by undergoing deflection; and weight portions provided between adjacent ones of the elastic spoke portions. The fastening portion, inertial ring, elastic spoke portions, and weight portions are formed integrally by casting or forging.

A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. For smaller units, the bearing cooling system is effective to enable a flywheel with a moment of inertia less than 40,000 lb in.sup.2 to be accelerated at a rate of 5 rpm/s or greater. For larger units, the bearing cooling system is effective to enable a flywheel with a moment of inertia greater than 40,000 lb in.sup.2 to be accelerated at a rate of 2.5 rpm/s or greater.

A method for producing a flywheel includes producing a damping plate part by permanently connecting at least a first metallic plate element provided for the flywheel to at least one further material layer to form a sandwich component. According to the method, the first plate element is connected by a joining process to at least a second, parallel plate layer, so that they lie on one another to form a disc-shaped structural unit. According to the method, at least two sheet metal layers from different materials and/or at least two sheet metal layers having different material strengths are connected with each other. This enables a large variance for the production of flywheels. In this way, it is possible, for example, to produce a flywheel having a plurality of superimposed plates adapted to the respective load situation in a defined flexibility.

An added inertia resonant system (12) for a power toothbrush (10) comprises a drive shaft (16), a drive system (22), and at least one inertial weight member (24). The drive shaft (16) has a principal axis (26) that defines a center of rotation. The drive system (22) imparts a reciprocating motion to the drive shaft (16) about the principal axis(26). The at least one inertial weight member (24) couples to the drive shaft (16) and comprises a planar material having a complex shape balanced along an x-, y-and z-axis to enable the drive system (22) to achieve low power, high amplitude motion of the drive shaft (16) when placed under user loading. A method for providing added inertia in a resonant system for a power toothbrush is also disclosed.

A drivetrain module for a motor vehicle including a flywheel connectable to a crankshaft, and a crankshaft starter-generator which has a rotor. The flywheel has a multiplicity of fastening points. In a region of magnetically soft action of the rotor, a multiplicity of passage openings is arranged in each case so as to be spatially assigned to the fastening points of the flywheel. Through the passage openings, pin-like fastening elements interact with the respectively assigned fastening points for the rotationally conjoint connection of rotor and flywheel.

A rotary tilling apparatus separates a power transmission system starting from a flywheel to a passive movement device through an elastic coupler from another power transmission system starting from the flywheel to a rotor of a motor generator, and thereby reduces a load applied to the rotor and prevents the power transmission system of the passive movement device from providing a negative effect to an engine and the rotor. A parallel hybrid power transmission mechanism includes an engine, a crank shaft disposed on the engine, a motor generator, a passive movement device configured to receive a motive power of the motor generator, an input shaft disposed on the passive movement device, a flywheel coupled to the crank shaft, an elastic coupler configured to couple the flywheel to the input shaft, and a rotor disposed on the motor generator and coupled to the fly wheel.

A gyroscopic roll stabilizer includes a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling one or more bearings supporting the flywheel. The bearing cooling system enables heat generated by the bearings to be transferred through the flywheel shaft to a heat sink disposed within a cavity in the end of the flywheel shaft, and then external to the enclosure.