Abstract: A liquid cooling system includes a cooling body (1) defining an hollow portion receiving a pump (3) and a number of cooling fins (18) therein, and a contact portion for contacting an electrical component. The cooling body defines a passageway therein filled with liquid coolant, and an inlet (124) and an outlet (125) both in communication with the passageway. The pump defines an exit (31) and an entrance (32) connected to the inlet and the outlet of the cooling body respectively by two tubes (5). Heat is transferred from the electrical component to the contact portion, and then conducted to the coolant, and conducted to other portions of the cooling body as the coolant flows through the passageway. The heat is then conducted to the cooling fins for dissipation.

Abstract: A system and method for controlling the level of a process water pond is provided. According to one aspect of the invention, the method includes increasing the evaporation rate of the process water pond through the addition of heat from a power plant. According to another aspect, the method includes pumping process water through a condenser of the power plant. According to a further aspect, the method includes pumping substantially pure feedwater between a condenser of the power plant and a heat exchanger in thermal communication with the process water pond. According to yet another aspect, the method includes selectively pumping feedwater between a cooling tower and a condenser of the power plant, or pumping process water between the process water pond and the condenser. Aspects further provide a method for increasing recovery of substances contained in process water, and a method for cleaning a stagnant process water pond.

Abstract: A heat dissipation device is described. The heat dissipation device is suitable for electrical equipment, and particularly for a notebook computer. The heat dissipation device has a cooling fan and a plurality of heat dissipation fins. The heat dissipation fins are disposed at an outlet of the cooling fan to exhaust heat on the heat dissipation fins with airflow generated by the cooling fan. Each of spaces between the adjacent heat dissipation fins is determined so as to make the airflow velocity uniform. A preferred predetermined space is about C1×1/(V2?1), where V is an original airflow velocity at the adjacent heat dissipation fins and C1 is a coefficient.

Abstract: A heat exchanger useful for high temperature applications such as EGR cooling and fuel reformer applications comprises a tube bundle made up of a plurality of tubes, each having at least one end expanded to an enlarged polygonal cross-section, and having central portions with a generally smaller cross section. When the tubes are formed into a bundle, the enlarged end portions nest with one another and interstitial spaces are provided between the central portions of the tube. The enlarged end portions are preferably retained by a header ring having a multifaceted inner peripheral sidewall which is adapted to form brazed lap joints with the outward facing surfaces of the peripheral tubes end portions in the tube bundle. In one preferred arrangement, axially aligned enlarged portions are provided intermediate the ends of at least some of the tubes. These enlarged intermediate portions nest with one another and eliminate or reduce the need for baffle plates.

Abstract: A heat exchange assembly adapted for use in a water tank is provided. The heat exchange assembly includes a tube having end portions and a coiled portion between the end portions. A fitting is connected to at least one of the end s portions of the tube. The fitting has an end configured to extend through an opening in the water tank, and a surface positioned to limit the extension of the end through the opening in the water tank. The fitting also has an opposite end defining a bore configured to receive one of the end portions of the tube and to limit the extension of the end portion of the tube into the opposite end of the fitting. The bore extends axially beyond the surface of the fitting.

Abstract: An evaporator includes an enclosure having a fluid inlet manifold and a vapor outlet manifold. At least one blind passageway is arranged within the enclosure so as to open into a portion of the vapor outlet manifold. The interior surface of the enclosure that defines each passageway is covered with a capillary wick. A porous valve is arranged in fluid communication between the fluid inlet manifold and a blind end of the at least one blind passageway.

Abstract: A heat transfer tube and a method of forming a heat transfer tube with indents formed in the opposed walls. The indents may be cold welded or forge welded such that dimples or indentations meet in the middle of the tube. The bottom of a first indentation disposed on a first side of the tube is welded to the bottom of a second indentation formed in the opposite side of the tube.

Abstract: What is proposed is a heat-transfer interface device for use in a range of up 320° C. working temperatures for transfer of heat from a source of heat to a heat-receiving object under severe conditions. The device comprises an elastomeric material filled with an electrically-nonconductive and thermally-conductive filler material. The elastomeric material may have recesses on the surface or the surface may be curved, e.g., on the side facing the source of heat for forming a space between the surface of the device and the mating surface of the source of heat. The elastomeric material is clamped between the heat source and heat receiver in a compressed state so that when it is expanded under the effect of an increased temperature, the material is redistributed and the recesses are flattened. The elastomeric material comprises perfluoroelastomer polymer, and the filler can be selected from boron nitride, aluminum nitride, beryllium oxide, etc.

Abstract: An upper opening portion (74, 75) and lower opening portion (76, 77) are arranged in a door body (13b, 14b) located below a side window (13a, 14a), and an air conditioning unit (15, 16) is arranged inside the door body (13b, 14b), and a rotary position of a scroll casing (62, 63) of a blower (56, 57) is selected so that air can flow from the lower opening portion (76, 77) to the upper opening portion (74, 75) at the time of air-cooling and air can flow from the upper opening portion (74, 75) to the lower opening portion (76, 77) at the time of heating.

Abstract: A transmission line for downhole tools that make up all or part of a tool string for drilling and production of oil, gas, and geothermal wells that can withstand the dynamic gravitational forces and other accelerations associated with downhole excavations. The transmission line comprises a metal tube, or outer conductor, that houses a coaxial wire inner conductor. A non-metallic dielectric material is interposed between the inner and outer conductors. The outer and inner conductors and the dielectric are sufficiently compressed together so that independent motion between them is abated. Compression of the components of the transmission line may be achieved by drawing the transmission through one or more dies in order to draw down the outer conductor onto the dielectric, or by expanding the inner conductor against the dielectric using a mandrel or hydraulic pressure. Non-metallic bead segments may be used in aid of the compression necessary to resist the dynamic forces and accelerations of drilling.

Abstract: A method and related system of determining formation density by compensating actual inelastic gamma rays detected from a pulsed-neutron tool for the effects of neutron transport. The method and systems may model response of the tool and use the modeled response as an indication of an amount to compensate detected inelastic gamma rays.

Abstract: In a method of crude oil production where at a well head a mixture of particulates, crude oil and water is produced for storing in a production tank for settlement of the mixture in to the constituent parts for separate extraction from the tank or the mixture is pumped though a pipeline to a remote location, the mixture is transferred from the well head to the production tank or to the pipeline through a transfer duct in which an initial separation of the mixture is caused by heating material in the duct by a surrounding jacket and by running an auger flight with a ribbon flight in the duct which carries the particulate materials along the duct for discharge.

Abstract: A method for pressure- and flow-prevetive fixing of well pipes, preferably liners and casings (14, 54, 60, 66) in a well when drilling the well, wherein the method also may be used in a completed well in order to place a pressure- and flow-preventive barrier in an annulus (16) surrounded by at least one leaking well pipe. The method comprises the use of granular particles of unconsolidated matter which, by means of their particle sorting, are arranged with a suitably small permeability, and wherein the particles of unconsolidated matter thereafter are mixed with water and potential other additives to become a fluidised mixture of unconsolidated matter (22) subsequently being placed, preferably by pumping, as a pressure- and flow-preventive barrier of unconsolidated matter (38, 56, 62, 68) in the pertinent annulus (16).

Abstract: A monobore release for tubing conveyed perforating in a subterranean well. In a described embodiment, a well perforating system includes a release assembly interconnected in a tubular string. At least one perforating gun is releasably secured to the tubular string by the release assembly while the tubular string is conveyed into the well. The release assembly permits the perforating gun to be retrieved from the well through the tubular string, and also permits the perforating gun to be separated from the tubular string in the well.

Abstract: A formulation containing a copolymer derived from a cationic monomer effectively inhibits and controls the formation of inorganic scales. The formulation has particular application in the removal of zinc sulfide and iron sulfide scales formed when zinc bromide brines are used as completion fluids. The copolymer exhibit high solubility in high-density brines, such as zinc bromide brines. The polymers may be introduced into an oil or gas well as a portion of a carrier fluid or with brine. The preferred copolymer for use in the invention contains an acrylamide unit and a diallyldimethylammonium salt and, optionally, an acrylic acid or a salt thereof. The weight average molecular weight of such inhibitor copolymers is generally between from about 500,000 to about 5,000,000.

Abstract: A method of acidizing a subterranean formation with a diverting agent composed of a gelled or thickened viscoelastic foam or fluid generated from (i.) an amidoamine oxide gelling agent and (ii.) an acid or foam, water and/or brine. The gelled or thickened foam or fluid may be generated in-situ or introduced directly into the formation by mixing of the amidoamine oxide gelling agent and acid or foam, water and/or brine. As the acid spends, the acidizing fluid thickens. When the acid is further spent, the fluid viscosity declines eventually returning to a low viscosity state, allowing for easy cleanup. The process allows for selective acidizing of less permeable zones of the formation and more uniform stimulation of the hydrocarbon bearing formation.

Abstract: An erectable arm assembly for use in a borehole, the erectable arm assembly comprising a main body and an arm member, the arm member being able to move between a collapsed position in which the assembly can be removed from the borehole and an erected position, the erectable arm assembly being adapted to house a fluid drilling assembly comprising a fluid cutting device and a flexible hose drill string such that the arm member during erection can contain at least part of the fluid drilling assembly, and when in the erected position the arm member is able to guide the fluid cutting device towards the borehole wall, the assembly further including at least one sensor for monitoring the arm member or the fluid drilling assembly.

Abstract: Radial penetrator assembly 10 conducts fluid through the passageway in the wall to a wellhead housing 18 and into a port in a tubular hanger 14 positioned within a central bore 19 in the wellhead housing. The flexible tube 22 extends between the passageway in the wellhead housing and the port in the inner member, while sleeve-shaped adapter 30 extends radially from the wellhead housing and has an adapter bore sealed to a radial passageway in the wellhead housing. A radial outer seal 64 seals between the radial outer portion of the adapter 30 and a radially outer portion of the flexible tube 22. The flexibility of the tube permits an inner portion axis with the tube to be offset or slanted with respect to an outer portion axis of the tube.

Abstract: A method for controlling the ascent and descent of a tubular member passing through a pipe or casing slip into a well bore. A float control member is affixed beneath the top surface of the pipe or casing slip. The control member is activated to control the raising or lowering of the tubular member. A piston within a cylinder housing is positioned below the top surface of the slip. As the tubular member is lowered, but before there is significant weight on the supporting structure, the piston is moved to its maximum height extension. Once the slips are set and the weight of the tubular member is applied to the slips, the piston begins to descend in the cylinder housing floating the final descent of the string. The string may be raised by activating a pump to force fluid within the housing chamber, raising the piston and thereby raising or lifting the string.

Abstract: A modular weight bar usable in conjunction with downhole tools disposed within a pressurized wellbore. The modular weight bar adds mass to the downhole tool so it can be suspended and lowered within the pressurized wellbore on wireline. The modular weight bar is separatable from the downhole tool at a selected depth within the wellbore thereby allowing the downhole tool to be further lowered within the wellbore without being accompanied by the weight bar.

Abstract: A method and apparatus for forming an elastic memory foam into an expansion element with an outer diameter larger than a borehole, heating the expansion element to its transition temperature and compressing it to a smaller run-in diameter, cooling the compressed expansion element below its transition temperature and running it into the borehole, then raising the expansion element to its transition temperature to cause it to expand and seal against the borehole wall. Expansion can be enhanced by expanding a mandrel on which the expansion element is formed.

Abstract: A sprinkler head assembly includes a sprinkler head body, a frame including a pair of arms extending from the body from opposed sides of the body, and a deflector mounted to the frame spaced from the outlet opening of the sprinkler head body for deflecting fire extinguishing liquid flowing from the outlet opening. The sprinkler head assembly is adapted to direct a greater proportion of the fire extinguishing liquid from one side of the sprinkler body than the other side of the sprinkler body.

Abstract: There is provided a system and method that uses solid CO2 for the purposes of fire suppression. In particular, there is provided a method of preventing fires by covering an area, a structure or an item to be protected with a layer of solid CO2. There is also provided a fire fighting and prevention apparatus that comprises a vehicle, a source of CO2, a solid CO2 generating assembly and a solid CO2 distributor. This vehicle can be position to cover or fill a structure that is already on fire with solid CO2 to put out the fire, or cover or fill a structure that is in the risk of catching fire to prevent that structure from catching fire.

Abstract: A method and an apparatus for controlling the rate of pressure applied to an air controlled device. The apparatus includes a flow restrictor, a regulator, and a dome loaded regulator. The regulator is configured to be operatively connected to a pressure source and is set to a first selected pressure. The flow restrictor is arranged to control the rate of applying pressure to the air controlled device after the first pressure is reached. The dome loaded regulator is in communication with the regulator and the flow restrictor such that the regulator and the flow restrictor alternately determine the flow rate from the pressure source to the air controlled device. The method includes setting a predetermined parameter and automatically reducing the rate of applying pressure to the air controlled device after the predetermined parameter is reached.

Abstract: To provide a cooling method of a superconducting cable line wherein moistures contained in the cable in the superconducting cable line after laid is removed before cooling, so that solidification of the moistures can be prevented from clogging of piping including a coolant flow channel and a return pipe. There is provided an inert gas generating vessel so that before the coolant is flown into the superconducting cable line 15, the inert gas is blown into the cable line from an inflow pipe 23 connected with a supply pipe 19? and is discharged from a discharge pipe 22 together with the gas. The inert gas is preheated by a heater 3 before feeding it into the cable line. The discharge pipe 22 connected with a discharge side B of the return pipe 19 is provided with a moisture measuring instrument 20 to measure a moisture content of the discharged gas.

Abstract: A coaxial line, via which HF currents of more than 1 MW may be transmitted due to improved cooling, even in continuous operation, includes an inner conductor (3), through which the coolant may be conducted. The coolant may be supplied and removed via hollow insulating material struts (5). Particularly if a liquid coolant is used, a significant savings in weight is achieved practically without reducing the efficiency of the cooling if a tube (7) of smaller diameter is positioned in the inner conductor (3) and the coolant only flows through the annular space (8) between this tube (7) and the inner conductor (3).

Abstract: The invention describes a fiber optic module package which uses a metal-to-metal contact seal between a lid and a module housing. The metal-to-metal contact seal provides a sealing mechanism between the lid and the module housing. The module housing has a knife-shaped edge that can bite into a bottom surface of the lid when pressure is exerted on the lid. In a first embodiment, the module housing has a side slot in which an outer wall of the lid can enter which serves as a holding mechanism between the lid and the module housing. In a second embodiment, the module housing has an interior wall which can be pressed into a curved surface of the lid that serves as a holding mechanism between the lid and the module housing. In a third embodiment, multiple screws are inserted through multiple holes on the lid and into the module housing which serve as a holding mechanism between the lid and the module housing.

Abstract: A module includes a ceramic substrate, first and second electrodes provided on the ceramic substrate, a component having third and fourth electrodes connected to the first and second electrodes, respectively, and a resin filled in a space between the component and the ceramic substrate. The ceramic substrate has a surface thereof having a recess formed therein. The first and second electrodes are provided on the surface of the ceramic substrate so that the recess is located between the first and second electrodes. The component is located over the recess and spaced from the ceramic substrate with a space including the recess. The space including the recess is filled with the resin. The module allows each component to be surface mounted at higher bonding strength, thus preventing short-circuit between the electrodes on the substrate and improving the operation reliability.

Abstract: According to one aspect of the invention, an electronic assembly and a method for constructing an electronic assembly are provided. Insulating bodies interconnect a heat sink plate, or support plate, and a plurality of support members to form a heat sink assembly. The heat sink assembly is placed on a circuit board along with a semiconductor package. The entire circuit board is heated to solder the heat sink assembly and the semiconductor package to the circuit board. The insulating bodies thermally separate the heat sink plate and the support members so that heat is not conducted from the support members to the heat sink plate, and the heat sink plate and semiconductor package may be attached to the circuit board in a one-step heating process.

Abstract: A method for manufacturing a cover assembly including a transparent window portion and a frame of gas-impervious material that can be hermetically attached to a micro-device package base to form a hermetically sealed micro-device package. First, a frame of gas-impervious material is provided, the frame having a continuous sidewall defining a frame aperture there through. The sidewall includes a frame seal-ring area circumscribing the frame aperture. A sheet of a transparent material is also provided, the sheet having a window portion defined thereupon. The window portion has finished top and bottom surfaces. A sheet seal-ring area is prepared on the sheet, the sheet seal-ring area circumscribing the window portion. The frame is positioned against the sheet such that at least a portion of the frame seal-ring area and at least a portion of the sheet seal-ring area contact one another along a continuous junction region that circumscribes the window portion.

Abstract: A mounting system for securing an electrical box within a wall of a building. The electrical box is of typical construction having an open side thereof. The mounting system consists of an elongated bracket having one end region secured to the wall structure and a generally rectangular opening therein sized to permit access to the open side of the electrical box. An adapter plate is mounted to the bracket with this adapter plate having a central opening that is also sized to permit access to the open side of the electrical box. The adapter plate is further configured with box mounting structure to secure the electrical box to the adapter plate.

Abstract: Transmission of electrical signals can be conducted over a rail. The rail, which may be an at least partially open rail structure, may be disposed within an enclosure, and can be used to transmit data and power signals to an assembly of electrical components. A connector assembly may also be provided to facilitate the transmission of data and power signals between the components and the rail.

Abstract: The invention relates to a bushing (1) for supporting electric conductors. Said bushing contains a flange section (2), a corrugated section (3), which projects above the flange section in the longitudinal direction of the electric conductor, in addition to at least one retaining section (4), which has bushing orifices (7) that are open on both sides for receiving busbars. The aim of the invention is to reduce the production costs and simplify the assembly of a bushing of this type. To achieve this, the bushing (1) is configured in one-piece, each retaining section (4) being solely supported on the flange section (2) by means of the corrugated section (3).

Abstract: A tool for twisting of the bare ends of electrical wires or conductors or connectors while simultaneously restraining rotation of wires at a predetermined distance from their bare ends. The tool reduces repetitive motion of the user when making electrical connections and can also enables the user to make more secure electrical connections. The various embodiments illustrate the invention as a hand tool or in conjunction with a power tool.

Abstract: An intermediate jointing structure having excellent mechanical and electrical characteristics and method of preparing the same. The intermediate jointing structure includes a metal pipe and a jointing sleeve. The metal pipe is inserted between a pair of superconducting cables and is fixed to the formers by welding. A plurality of superconductor wires, shorter than the conductive metal tube, are arranged around a conductive metal tube in a longitudinal direction. The arranged superconductor wires are taped with Ag tape so as to form the jointing sleeve. The jointing sleeve is jointed and fixed on an outer surface of the metal pipe.

Abstract: The present invention relates to a composite insulator comprising: (i) a composite body having at least two connectors and (ii) a housing, wherein the housing includes silicone rubber and the composite body is located inside the housing.

Abstract: An object of the present invention is to provide a method of manufacturing a hybrid integrated circuit device, in which multiple circuit boards are manufactured from one large metal board by dicing. The hybrid integrated circuit device of the present invention includes a circuit board with a surface provided with an insulating layer, and conductive patterns provided on the insulating layer. Circuit elements are electrically connected to the conductive patterns. Further, each side surface of the circuit board includes a first inclined portion extending obliquely downward from a peripheral portion of the surface of the circuit board, and a second inclined portion extending obliquely upward from a back surface of the circuit board and formed to be larger than the first inclined portion.

Abstract: A printed circuit board and a routing scenario thereof are disclosed. The printed circuit board includes three dielectric layers, two signal layers and several differential pairs. Some differential pairs are disposed in one signal layer, while some differential pairs are interleavingly disposed in the adjacent other signal layer. The differential pairs in one signal layer carries signals that flows to one direction, while the differential pairs in the adjacent signal layer carries signals that flows to an opposite direction. Under such a routing scenario, the crosstalk between differential pairs in adjacent signal layers may be reduced.

Abstract: A method of fabricating printed circuit boards integrating thick film resistor components and thin film circuit portions thereon is disclosed. This is a two-phase process, where the first phase is to create multiple thick film resistors, and the second phase is to create a thin film circuit portion on the substrate with thick film resistors in existence, involving the printing of the electrodes and the resistive coating for the thick film resistors, and the printing of a low temperature passivation layer over the resistors; and the thin film circuit is formed by titanium and copper layers over the substrate, and electroplating of interconnections to form copper plated circuit. The present fabrication process does not require drilling of holes nor electroplating of leads to the resistors, thus the whole process can be automated to a greater extent than with conventional techniques.

Abstract: In a soldering method for soldering an electronic component including a palladium or palladium alloy layer formed on a surface of the electronic component and also including a soldering lead terminal onto a printed wiring board including a soldering land and plated through hole, a solder layer containing tin and zinc as main components is formed on the surfaces of the land through hole by a HAL treatment. The lead terminal is inserted and mounted in the through hole. The printed wiring board is brought into contact with jet flows of a solder containing tin and zinc as the main components to thereby supply a solder to the land and through hole.

Abstract: A resistivity logging sensor for logging while drilling a well using an oil-based mud includes a sensor body; a first current injector electrode disposed on the sensor body, wherein the first current injector electrode is electrically insulated from the sensor body; at least two current return electrodes disposed on the sensor body at a selected distance from the first current injector electrode, wherein the at least two current return electrodes are disposed proximate to each other and are electrically insulated from the sensor body; and an electrical source configured to energize the first current injector electrode with a current having a voltage of no less than 50 mvolts and a frequency of no less than 1 KHz.

Abstract: Methods and apparatus facilitating logging-while-drilling (LWD) using a multi-pole acoustic transmitter source. The multi-pole transmitter source enables measurement of formation velocities, including shear wave velocities through formations that are slower than velocities through local fluids. The methods and apparatus are particularly well suited for LWD and wireline seismic surveys in which both the seismic or acoustic source and receivers are both deployed in a borehole, but may also be used for VSPs (vertical seismic profiling).

Abstract: A method of reducing the torque required to provide relative rotation of two connected members includes providing impacts at or adjacent the connection between the two members at a rate of at least two impacts per second. An apparatus for reducing the torque required to provide relative rotation of two connected members includes an impact member adapted to provide an impact to at least one of the connected members, a driver for driving the impact member, wherein the driver is operable to cause the impact member to automatically and repeatedly impact upon the at least one member.

Abstract: The pressure reading tool includes a housing with an interior chamber and an orifice extending from the chamber to the exterior of the housing. A pulse member with a magnetostrictive ring and an excitation source are disposed within the chamber to produce a highly agitated fluid discharge through the orifice. The magnetostrictive ring, chamber volume, and orifice cooperate to induce Helmholtz resonance frequencies in the fluid in the chamber to thereby enhance the agitation of the fluid discharge. A sheathing encapsulates the pulse member to protect it from contact with the fluid. A dampening element is also interposed between the pulse member and housing to isolate vibration.

Abstract: This invention relates to a method of achieving a solid-liquid separation of an oil-based mud comprising the step of contacting said oil-based mud with a water-in-oil emulsion comprising a polymer derived from at least one water-soluble monomer, where the polymer is not dissolved prior to contact with the oil-based mud, mixing the water-in-oil emulsion and the oil-based mud and separating the solid phase from the liquid phase in the oil-based mud. In addition, this invention also relates to a composition comprising an oil-based mud with a water-in-oil emulsion comprising a polymer derived from at least one water-soluble monomer, wherein the polymer is not dissolved prior to contact with the oil-based mud.

Abstract: A drill member for percussive rock drilling is formed by forming a compound component and friction welding the compound component to the end of a drill rod. The compound component is formed by welding a core part within a shell part and machining a thread into either the shell part (male thread) or core part (female thread). The part in which the thread is machined is formed of low alloy steel, and the other part is formed of stainless steel, wherein the thread bottom is formed of stainless steel, and the thread crests are formed of low alloy steel.

Abstract: A shaped insert that includes a top portion, and a grip length, wherein the grip length is modified to have a non-uniform cross sectional area is disclosed. In another case, a shaped insert includes a top portion, and a grip length, wherein the grip length is modified such that the insert is non-cylindrical. In another case, a shaped insert includes a top portion, and a grip length, wherein the grip length is coated in a non-uniform manner.

Abstract: A balance (1, 101) has a draft protection device (2) that encloses a weighing compartment surrounding the weighing pan (15). A rear wall (22, 122) delimiting the weighing compartment on one side is made of a material (26) that diffuses the transmitted ambient light. The translucent, light-diffusing material (26) is in particular a frosted glass.

Abstract: A programmable event driver/interface has timekeeping and scheduling functions and tone and voice capabilities. A software-based interface allows for direct communication with individual annunciators and dynamic grouping of annunciators by zone. System state of health can be ascertained periodically for each annunciator, displayed in a visual summary, stored, and time tagged. Both tones and audio signals such as voice and radio can be commanded to be output by individual annunciators as well as by zones and by all annunciators at once. Schedules, including time-of day, day-of week, and date for annunciator outputs can be programmed for any or all annunciators.

Abstract: A vehicle drive device has a reduction gear is installed between first and second electric motors and a wheel axle so that the first and second electric motors can transmit torque to the wheel axle at different reduction ratios. More specifically, the reduction gear is configured such that the torque of the first electric motor is delivered to the wheel axle using a reduction ratio suitable for low speed travel and the torque of the second electric motor is delivered using a reduction ratio suitable for high speed travel. Thus, the vehicle drive device can deliver sufficient drive torque at rotational speeds ranging from low speeds to high speeds while preventing the size of the rotary drive source used to drive the vehicle from becoming large.