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Hydraulic Motor
A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation). The hydraulic motor is the rotary counterpart of the hydraulic cylinder as a linear actuator. Most broadly, the category of devices called hydraulic motors has sometimes included those that run on hydropower (namely, water engines and water motors) but in today's terminology the name usually refers more specifically to motors that use hydraulic fluid as part of closed hydraulic circuits in modern hydraulic machinery. Conceptually, a hydraulic motor should be interchangeable with a hydraulic pump because it performs the opposite function - similar to the way a DC electric motor is theoretically interchangeable with a DC electrical generator. However, many hydraulic pumps cannot be used as hydraulic motors because they cannot be backdriven. Also, a hydraulic motor is usually designed for working pressure at both sides of the motor, whereas mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gear Pump
A gear pump uses the meshing of gears to pump fluid by displacement. They are one of the most common types of pumps for hydraulic fluid power applications. The gear pump was invented around 1600 by Johannes Kepler. Gear pumps are also widely used in chemical installations to pump high viscosity fluids. There are two main variations: ''external gear pumps'' which use two external spur gears, and ''internal gear pumps'' which use an external and an internal spur gear (internal spur gear teeth face inwards, see below). Gear pumps are ''positive displacement'' (or ''fixed displacement''), meaning they pump a constant amount of fluid for each revolution. Some gear pumps are designed to function as either a motor or a pump. Theory of operation As the gears rotate they separate on the intake side of the pump, creating a void and suction which is filled by fluid. The fluid is carried by the gears to the discharge side of the pump, where the meshing of the gears displaces the flu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backdrive
A backdrive is a component used in reverse to obtain its input from its output. This extends to many concepts and systems from thought based to practical mechanical applications. Not every system can be backdriven. A DC electrical generator can be implemented by backdriving a DC electric motor, however a worm drive works only in one direction. Example: A CNC vertical mill has a vertical lead screw on the Z-axis. A low lead screw pitch (i.e. 5 turns per inch or fewer) means when the driving motor power is removed such as by turning the machine off, the weight of the spindle will cause the lead screw to rotate as the spindle motor falls down. The solution to prevent back-driving is to use a finer (higher) lead screw pitch (i.e. 10tpi or greater) or have a locking mechanism. Another example is the practice to add swivel caster wheels on a mobile robot A mobile robot is an automatic machine that is capable of locomotion.Hu, J.; Bhowmick, P.; Lanzon, A.,Group Coordinated Control of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Piston Pump
An axial piston pump is a positive displacement pump that has a number of pistons in a circular array within a ''cylinder block''. It can be used as a stand-alone pump, a hydraulic motor or an automotive air conditioning compressor. Description An axial piston pump has a number of pistons (usually an odd number) arranged in a circular array within a ''housing'' which is commonly referred to as a ''cylinder block'', ''rotor'' or ''barrel''. This cylinder block is driven to rotate about its axis of symmetry by an integral shaft that is, more or less, aligned with the pumping pistons (usually parallel but not necessarily). *Mating surfaces. One end of the cylinder block is convex and wears against a mating surface on a stationary ''valve plate''. The inlet and outlet fluid of the pump pass through different parts of the sliding interface between the cylinder block and valve plate. The valve plate has two semi-circular ports that allow inlet of the operating fluid and exhaust of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerotor
A gerotor is a positive displacement pump. The name ''gerotor'' is derived from "generated rotor". A gerotor unit consists of an inner and outer rotor. The inner rotor has ''n'' teeth, while the outer rotor has ''n''+1 teeth; with ''n'' defined as a natural number greater than or equal to 2. The axis of the inner rotor is offset from the axis of the outer rotor and both rotors rotate on their respective axes. The geometry of the two rotors partitions the volume between them into ''n'' different dynamically-changing volumes. During the assembly's rotation cycle, each of these volumes changes continuously, so any given volume first increases, and then decreases. An increase creates a vacuum. This vacuum creates suction, and hence, this part of the cycle is where the inlet is located. As a volume decreases compression occurs. During this compression period, fluids can be pumped, or, if they are gaseous fluids, compressed. Gerotor pumps are generally designed using a trochoidal inne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerotor Anm
A gerotor is a positive displacement pump. The name ''gerotor'' is derived from "generated rotor". A gerotor unit consists of an inner and outer rotor. The inner rotor has ''n'' teeth, while the outer rotor has ''n''+1 teeth; with ''n'' defined as a natural number greater than or equal to 2. The axis of the inner rotor is offset from the axis of the outer rotor and both rotors rotate on their respective axes. The geometry of the two rotors partitions the volume between them into ''n'' different dynamically-changing volumes. During the assembly's rotation cycle, each of these volumes changes continuously, so any given volume first increases, and then decreases. An increase creates a vacuum. This vacuum creates suction, and hence, this part of the cycle is where the inlet is located. As a volume decreases compression occurs. During this compression period, fluids can be pumped, or, if they are gaseous fluids, compressed. Gerotor pumps are generally designed using a trochoidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotary Vane Pump
A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside a cavity. In some cases these vanes can have variable length and/or be tensioned to maintain contact with the walls as the pump rotates. It was invented by Charles C. Barnes of Sackville, New Brunswick, who patented it on June 16, 1874. There have been various improvements, including a variable vane pump for gases (1909). They are considered less suitable than other vacuum pumps for high-viscosity and high-pressure fluids, and are complex to operate. They can endure short periods of dry operation, and are considered good for low-viscosity fluids. Type The simplest vane pump has a circular rotor rotating inside a larger circular cavity. The centers of these two circles are offset, causing eccentricity. Vanes and seal on all edges, creating vane chambers that do the pumping work. On the suction side of the pump the vane chambers are increased in volume. These are filled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swashplate Engine
A cam engine is a reciprocating engine where, instead of the conventional crankshaft, the pistons deliver their force to a cam that is then caused to rotate. The output work of the engine is driven by this cam. Cam engines are deeply rooted in history. The first engine to get an airworthiness certificate from the United States government was, in fact, a radial cam engine. A variation of the cam engine, the swashplate engine (also the closely related wobble-plate engine), was briefly popular. These are generally thought of as internal combustion engines, although they have also been used as hydraulic- and pneumatic motors. Hydraulic motors, particularly the swashplate form, are widely and successfully used. Internal combustion engines, though, remain almost unknown. Operation Operating cycle Some cam engines are two-stroke engines, rather than four-stroke. Two modern example are the KamTech and Earthstar, both radial-cam engines. In a two-stroke engine, the forces on the pisto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutoff (steam Engine)
In a steam engine, cutoff is the point in the piston stroke at which the inlet valve is closed. On a steam locomotive, the cutoff is controlled by the reversing gear. The point at which the inlet valve closes and stops the entry of steam into the cylinder from the boiler plays a crucial role in the control of a steam engine. Once the valve has closed, steam trapped in the cylinder expands adiabatically. The steam pressure drops as it expands. A late cutoff delivers full steam pressure to move the piston through its entire stroke, for maximum start-up forces. But, since there will still be unexploited pressure in the cylinder at the end of the stroke, this is achieved at the expense of engine efficiency. In this situation the steam will still have considerable pressure remaining when it is exhausted resulting in the characteristic “chuff chuff” sound of a steam engine. An early cutoff has greater thermodynamic efficiency but results in a lower Mean effective pressure so less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillating Engine
An oscillating cylinder steam engine (also known as a wobbler in the US) is a simple steam-engine design (proposed by William Murdoch at the end of 18th century) that requires no valve gear. Instead the cylinder rocks, or oscillates, as the crank moves the piston, pivoting in the mounting trunnion so that ports in the cylinder line up with ports in a fixed port face alternately to direct steam into or out of the cylinder. Oscillating cylinder steam engines are now mainly used in toys and models but, in the past, have been used in full-size working engines, mainly on ships and small stationary engines. They have the advantage of simplicity and, therefore, low manufacturing costs. They also tend to be more compact than other types of cylinder of the same capacity, which makes them advantageous for use in ships. Operation alt=oscillating cylinder diagram, Operation of a simple oscillating cylinder steam engine The steam needs to be fed into the end of the cylinder at just t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-acting Cylinder
In mechanical engineering, the cylinders of reciprocating engines are often classified by whether they are single- or double-acting, depending on how the working fluid acts on the piston. Single-acting A single-acting cylinder in a reciprocating engine is a cylinder in which the working fluid acts on one side of the piston only. A single-acting cylinder relies on the load, springs, other cylinders, or the momentum of a flywheel, to push the piston back in the other direction. Single-acting cylinders are found in most kinds of reciprocating engine. They are almost universal in internal combustion engines (e.g. petrol and diesel engines) and are also used in many external combustion engines such as Stirling engines and some steam engines. They are also found in pumps and hydraulic rams. Double-acting A double-acting cylinder is a cylinder in which the working fluid acts alternately on both sides of the piston. In order to connect the piston in a double-acting cylinder to an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Tyne
The River Tyne is a river in North East England. Its length (excluding tributaries) is . It is formed by the North Tyne and the South Tyne, which converge at Warden Rock near Hexham in Northumberland at a place dubbed 'The Meeting of the Waters'. The Tyne Rivers Trust measure the whole Tyne catchment as , containing of waterways. Course North Tyne The North Tyne rises on the Scottish border, north of Kielder Water. It flows through Kielder Forest, and in and out of the border. It then passes through the village of Bellingham before reaching Hexham. South Tyne The South Tyne rises on Alston Moor, Cumbria and flows through the towns of Haltwhistle and Haydon Bridge, in a valley often called the Tyne Gap. Hadrian's Wall lies to the north of the Tyne Gap. Coincidentally, the source of the South Tyne is very close to those of the Tees and the Wear. The South Tyne Valley falls within the North Pennines Area of Outstanding Natural Beauty (AONB) – the second larges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
