Abstract: A beta-type free-piston Stirling cycle engine or cooler is drivingly coupled to a linear alternator or linear motor and has an improved balancing system to minimize vibration without the need for a separate vibration balancing unit. The stator of the linear motor or alternator is mounted to the interior of the casing through an interposed spring to provide an oscillating system permitting the stator to reciprocate and flex the spring during operation of the Stirling machine and coupled transducer. The natural frequency of oscillation, ?s, of the stator is maintained essentially equal to ? p ? 1 - ? p k p and the natural frequency of oscillation of the piston, ?p, is maintained essentially equal to the operating frequency, ?o of the coupled Stirling machine and alternator or motor.

Abstract: To provide a less expensive and high-efficient free-piston Stirling cycle machine with an outer diameter of entire machine being relatively small. In a Stirling cycle cooler as a free-piston Stirling cycle machine including a cylinder 7, a piston 18 which is reciprocable inside said cylinder 7 and an electromagnetic driving mechanism 19 for reciprocating said piston 18, said electromagnetic driving mechanism 19 is comprised of a mover 20 and a stator 35, said piston 18 and said mover 20 formed by disposing a permanent magnets 24 outside an inner yoke 23 made of magnetic flux conducting material are disposed in an axial alignment, and said stator 35 and said cylinder 7 are disposed in an axial alignment.

Abstract: To provide a less expensive and high-efficient free-piston Stirling cycle machine with an outer diameter of entire machine being relatively small. In a Stirling cycle cooler as a free-piston Stirling cycle machine including a cylinder 7, a piston 18 which is reciprocable inside said cylinder 7 and an electromagnetic driving mechanism 19 for reciprocating said piston 18, said electromagnetic driving mechanism 19 is comprised of a mover 20 and a stator 35, said piston 18 and said mover 20 formed by disposing a permanent magnets 24 outside an inner yoke 23 made of magnetic flux conducting material are disposed in an axial alignment, and said stator 35 and said cylinder 7 are disposed in an axial alignment.

Abstract: A beta-type free-piston Stirling cycle engine or cooler is drivingly coupled to a linear alternator or linear motor and has an improved balancing system to minimize vibration without the need for a separate vibration balancing unit. The stator of the linear motor or alternator is mounted to the interior of the casing through an interposed spring to provide an oscillating system permitting the stator to reciprocate and flex the spring during operation of the Stirling machine and coupled transducer. The natural frequency of oscillation, ?s, of the stator is maintained essentially equal to ?p ? p ? 1 - ? p k p and the natural frequency of oscillation of the piston, ?p, is maintained essentially equal to the operating frequency, ?o of the coupled Stirling machine and alternator or motor.

Abstract: An improved, free-piston, Stirling machine having at least three pistons series connected in an alpha Stirling configuration. Each cylinder is stepped so that it has a relatively larger diameter interior wall and a coaxial, relatively smaller diameter interior wall. Each piston is also stepped so that it has a first component piston having an end face facing in one axial direction and matingly reciprocatable in the smaller diameter cylinder wall and a second component piston having an end face facing in the same axial direction and matingly reciprocatable in the larger diameter, cylinder wall. One of the piston end faces bounds the compression space and the other end face bounds the expansion space. Preferably, each stepped piston has peripheral, cylinder walls that are axially adjacent and joined at a shoulder forming the end face of the larger diameter component piston.

Abstract: An apparatus for determining position of a free piston used in such as hydraulic compressor, which has no mechanical connection with crank shaft, and an apparatus for controlling reciprocating motion of the free piston are disclosed. A free piston position determining apparatus comprises a magnetic sensor disposed in a case containing a free piston, and a magnet disposed on the free piston. The magnet sensor generates pulse train when the magnet is positioned within a pre-determined distance form the magnet sensor. Stroke of the free piston is computed based on duration of the pulse, and offset of the average piston position from designed average position is computed based on interval of the pulse.

Abstract: The invention provides a compact and inexpensive cooling device with high heat transfer efficiency and with easy maintenance. The cooling device includes a condenser (10), an evaporator (20), and a pair of refrigerant flow passages between them. In each of the condenser (10) and the evaporator (20), through holes (11a, 21a) are formed in parallel with each other. The condenser (10) is formed in a cylindrical shape and installed around the cooling head of the refrigerator by a clamp (14). The evaporator (20) is installed the outside. The refrigerant is liquefied in the condenser (10) by releasing its heat, flows down into the evaporator (20) through the flow passage and is vaporized in the evaporator (20) by absorbing heat from the outside. The vaporized refrigerator flows up and returns into the condenser (10).

Abstract: The invention can prevent gas leakage and reduce friction force while relaxing tolerance for manufacturing a displacer and the like for Stirling cycle machines. Gas leakage between the outer periphery of a seal (1) and the inner peripheral surface (5a) of a cylinder (5) is prevented. Accordingly, precise finish of the radial clearance between the displacer (2) and the cylinder (5) is not required. As the difference of pressures between the front and rear spaces of the displacer (2) is small, the gas leakage is sufficiently prevented without pressing the seal (1) against the inner peripheral surface (5a) of the cylinder (5). On the other hand, as the friction force generated between them is significantly small, it does not affect the reciprocation of the displacer. As the seal (1) is provided so as not to be restricted axially and radially, the displacer is kept closely contacted with the inner peripheral surface (5a) of the cylinder (5) even if the displacer (2) eccentrically shifts.

Abstract: A gas restrictor particularly usrful for applicatio in gas bearing as used, for example, in free-piston Striling cycle machinery. Porous strip material together with a backing plate and orifice (bleed hole) is used to provide the restriction to the flow of gas into an annular gap between a piston and a cylinder.

Abstract: A heat pumping machine, such as used for home heating and cooling, has a free piston Stirling engine driving a vapor compression heat pump. The engine is mechanically linked to the compressor inside a common hermetically sealed enclosure. A fluid conducting passage connects the refrigerant flow path in communication with a working gas space in the Stirling engine. Although carbon dioxide may be used in both as the refrigerant and the engine working gas, preferably both helium and carbon dioxide are used and separated by a phase separator so that helium rich gas is directed into the Stirling engine and carbon dioxide rich fluid is directed through the heat pump.

Abstract: An enclosure for a refrigerated space. The enclosure may include a thermosiphon and a Stirling cooler. The thermosiphon may include a condenser end and an evaporator end. The ends may be connected by a small diameter pipe and a large diameter pipe. The Stirling cooler may drive the thermosiphon to cool the refrigerated space.

Abstract: A hollow evaporator is disposed in contact with the upper surface of the CPU. Heat from the CPU is absorbed by the evaporation of the refrigerant. The vaporized refrigerant ascends through the vapor flow channel by convection, flows into a condenser located above the evaporator, and radiates heat to be liquefied. The liquefied refrigerant flows down by its own weight through the liquid flow channel and returns to the evaporator. This circulation is repeated in this manner.