Showing papers on "Hydraulic machinery published in 2001"

Subsea mud pump and control system

Abstract: The invention is a subsea pump that includes pumping elements, each pumping element including a pressure vessel with a first and a second chamber therein and a separating member disposed between the first and second chambers. The first and second chambers are hydraulically connected to receive and discharge a hydraulic fluid and a drilling fluid, respectively. The separating member moves within the pressure vessel in response to a pressure differential between the first and second chambers. A hydraulic power supply is arranged to pump the hydraulic fluid to the first chamber of each of the pumping elements. A valve assembly is hydraulically coupled to the first chambers of the plurality of pumping elements and to the hydraulic power supply. Volume measurement devices are arranged to measure volumes of each of the first chambers and the second chambers. A valve controller is connected to the valve assembly and to the volume measurement devices, and the valve controller is arranged to control a rate and timing of a flow of the hydraulic fluid into the first chambers and a rate and timing of a flow of the hydraulic fluid out of the first chambers in response to the volume measurements. The valve controller is configured to maintain at least one of a substantially constant pump inlet pressure, a substantially constant pump discharge pressure, and a substantially constant total volume of the first chambers.

Non-linear adaptive robust control of electro-hydraulic systems driven by double-rod actuators

Abstract: This paper studies the high performance robust motion control of electro-hydraulic servo-systems driven by double-rod hydraulic actuators. The dynamics of hydraulic systems are highly non-linear and the system may be subjected to non-smooth and discontinuous non-linearities due to directional change of valve opening, friction and valve overlap. Aside from the non-linear nature of hydraulic dynamics, hydraulic servosystems also have large extent of model uncertainties. To address these challenging issues, the recently proposed adaptive robust control (ARC) is applied and a discontinuous projection based ARC controller is constructed. The resulting controller is able to take into account the effect of the parameter variations of the inertia load and the cylinder hydraulic parameters as well as the uncertain non-linearities such as the uncompensated friction forces and external disturbances. Non-differentiability of the inherent non-linearities associated with hydraulic dynamics is carefully examined and add...

Hydraulic system with cross function regeneration

Abstract: A regeneration method for a hydraulic system enables the fluid being forced from a first actuator to be used to power a second actuator. Often the force of the load acting on a hydraulic actuator is used to move the actuator into a given position which motion forces fluid from the actuator. Rather than simply draining that fluid to the system tank, the fluid is routed to a second actuator to be powered when the pressure of the fluid draining at the first actuator is greater than the pressure required to power the second actuator. At other times the draining fluid can be used to drive the pump which has been configured to operate as a motor thereby driving the prime mover connected to the pump. Alternatively the draining fluid can be routed to an accumulator where it is stored under pressure until needed to power an actuator of the system. A unique bidirectional pilot operated poppet valve.

Regenerative energy storage and conversion system

Abstract: A hydraulic circuit system and method for storing and converting hydraulic or mechanical energy to electricity wherein the hydraulic circuit system comprises: a power source for generating energy to produce electricity, a hydraulic power unit operably associated with the power source, one or more hydropneumatic accumulators operably associated with the hydraulic power unit, a hydraulic motor operably associated with the accumulators, a flywheel assembly operably associated with the hydraulic motor, a hydrostatic drive unit operably associated with the flywheel assembly, and a generator assembly operably associated with the hydrostatic drive unit wherein the generator assembly is further associated with the hydraulic power unit.

Hybrid machine with hydraulic drive device

Abstract: A hybrid machine with a hydraulic drive device having hydraulic actuators allowed to operate against and by external loads, comprising hydraulic cylinders (7), first hydraulic pumps (P1) connected, with closed circuits, to the head side pressure receiving chambers (7S) and the bottom side pressure receiving chambers (7L) of the hydraulic cylinders (7), and second hydraulic pumps (P2) connected, with open circuits, to the bottom side pressure receiving chambers (7L) and an external oil chamber (10), wherein the first and second hydraulic pumps (P1, P2) are connected to electric motors (M) so as to be driven.

Dual mode regenerative suspension for an off-road vehicle

Abstract: A vehicle suspension has one or more hydraulic cylinders connecting an axle to a frame of the vehicle and each cylinder has a first and second chambers. The suspension operates in either a regeneration mode, in which a fluid path is provided between the first and second chambers, and a double acting mode, in which the first and second chambers are isolated from each other and fluid flows between each chamber and a separate accumulator. The selection between the regeneration and double acting modes is made in response to the pressure level in the cylinder as determined by a pressure sensor of a closed loop control system or by the pressure versus current characteristics of a electrically operated valve in the suspension for a loop control system. The hydraulic system also is able to raise and lower the suspension as necessary due to changes in the load carried by the vehicle.

DP flow sensor using optical fibre Bragg grating

Abstract: An optical-based differential pressure (DP) flow sensor has been developed for an optically-powered hydraulic valve monitoring and feedback control system. The DP sensor employs two optical fibre single-mode Bragg grating elements, which are mounted on either side of the DP sensing diaphragm. The fluid flow-rate signal is obtained in the form of differential optical wavelength shift, and temperature compensation is provided. The sensor has been tested at fluid flow-rates from 0 to 800 cm 3 /s with temperature varying from 25 to 75°C. The optically-powered hydraulic valve using the DP flow sensor as a monitoring system has been tested with hydraulic oil with a flow-rate up to 6 cm 3 /s at a pressure of 700 kPa.

System and method for accumulating hydraulic fluid

Abstract: A hydraulic system is provided. The hydraulic system includes a a hydraulic actuator, a source of pressurized fluid, and a directional control valve controlling fluid flow into and out of the hydraulic actuator. An accumulator is disposed between a fluid input line and a fluid output line for the directional control valve. A regeneration control valve is disposed between the accumulator and the output of the source of pressurized fluid. A storage control valve is disposed between the fluid output line and a tank of the hydraulic system.

Hydroelectric turbine for producing electricity from a water current

Abstract: The invention takes energy from the periphery of a hydro electric turbine blade to produce electricity by mechanically driving a plurality of generators without the use of a hydraulic system.

Engineering Fluid Mechanics

Abstract: 1. Introduction to Fluid Mechanics 2. Hydrostatics 3. Fluid Dynamics 4. Dimensional Analysis 5. Open Channel Flows 6. Laminar Viscous Flows 7. Turbulent Viscous Flows 8. Measurement of Flow and Fluid Properties 9. Compressible Flows 10. Hydraulic Machinery 10. Conclusions

Electronically controlled hydraulic actuating system

Abstract: An electrically controlled hydraulic actuating system includes a servocontrol including a cylinder, a piston dividing the cylinder into two chambers each provided with a hydraulic connection port, a control valve connected to a hydraulic circuit. A two-way hydraulic pump is driven in rotation by an electric motor driven by power electronics. A switching device allows the connection ports of the chambers to be connected either to the control valve or the pump. The switching device connects the hydraulic connection ports both to the control valve and the pump, so as to allow the servocontrol to be supplied the sum of the hydraulic power delivered by the hydraulic circuit and the hydraulic power generated by the pump actuated by the electric motor.

Toroidal continuously variable transmission

Abstract: In a toroidal continuously variable transmission, a primary oil pump is driven by an engine, whereas a secondary oil pump is driven in response to rotation of a road wheel. A hydraulic servo mechanism is connected to a trunnion to create an offset of the trunnion from a neutral position for a tilting motion of the power roller. Also provided is a hydraulic system that supplies the hydraulic pressure discharged from the secondary pump to the hydraulic servo mechanism to prevent the offset of the trunnion in the trunnion-axis direction, corresponding to an upshift, occurring owing to rotation of the road wheel in a stopped state of the engine. A modulated hydraulic pressure, which is constantly produced by the hydraulic system during operation of the engine, acts to hold the secondary pump at either of an inoperative state and an unloaded condition during the operation of the engine.

Electro-hydraulically pressurized downhole valve actuator

Abstract: A petroleum well having a communication system and a hydraulic system is provided. The petroleum well includes a borehole and a piping structure positioned within the borehole. The communication system supplies a time varying electric current downhole along the piping structure. The hydraulic system (70), which is positioned downhole proximate the piping structure (26), receives the time varying current to operate an electric motor (78). The motor drives a pump (76) which pressurizes hydraulic fluid to selectively drive an actuator (84). The actuator (84) is operably connected to a downhole device, such as a shutoff valve, and operates the downhole device as the actuator (84) is driven by the pressurized hydraulic fluid.

Agricultural ground working implement with hydraulic downpressure circuit

Abstract: An agricultural implement includes a frame having a pair of tool-carrying wings pivotally mounted thereon for pivotal movement between raised transport positions and lowered ground-working positions Each wing has a hydraulic wing actuator connected thereto which is extendable and retractible for effecting the pivotal motion A hydraulic wing actuator circuit is connected to each of the wing actuators, which circuit, when connected to a tractor hydraulic system, enables the wing actuators to apply down pressure to said wings when the wings are in the lowered working positions A hydraulic pressure control valve system controls the down pressure exerted by the wing actuators

Implement pressure control for hydraulic circuit

Abstract: A method for controlling a hydraulic system may include receiving an input command from an input device, generating a desired working pressure value relating to a working chamber of an actuator based on the input command, and generating a desired pressure value relating to a non-working chamber of the actuator based on the input command. The method may also include operating a valve assembly to control a fluid flow condition of the working chamber and to control fluid flow from the non-working chamber.

Dynamic feed control system

Abstract: An injection molding apparatus and system are provided in which the rate of material flow during the injection cycle is controlled. According to one preferred embodiment, an injection molding system is provided that includes an injection molding machine including a hydraulic power source, a manifold for distributing material injected from said injection molding machine to a plurality of gates leading to one or more mold cavities, and a controller to individually control respective rates at which material is injected through said gates during an injection cycle. The controller is coupled to the hydraulic power source and the hydraulic power source supplies hydraulic power to both the injection molding machine and to control said respective rates.

Modeling and robust control design for aircraft brake hydraulics

Abstract: This article describes the modeling of an electrohydraulic pressure servo valve and brake hydraulic system, and the design of an inner-loop controller which can be used with independent anti-skid or auto-brake controllers. The effects of the connecting lines on stability and performance are explicitly taken into account in the control design by using the analytical solutions to 2D viscous compressible model of fluid motion in the pipe. The modal approximation technique is used in the simulations. In order to facilitate control design, singular perturbation analysis is employed to reduce the order of the model in a systematic fashion. Combining partial feedback linearization and linear H/sub /spl infin// control, guaranteed stability robustness against oil parameter variations and component wear is achieved. Both the model reduction and control design are described in some detail. Computational requirements are modest and with careful coding, the inner-loop controller can be incorporated into existing anti-skid controllers.

Hydraulic cylinder circuit

Abstract: A hydraulic cylinder circuit capable of operating a one side rod type hydraulic cylinder to an extension side and a retraction side at a same speed by a hybrid system driving a pump by a motor and simplifying a circuit configuration, characterized in that pressurized fluid is supplied to and discharged from both the head side and rod side pressure chambers (4a, 4b) of the one side rod type hydraulic cylinder (4) by both first and second hydraulic pumps (2, 3) driven by the motor (1) at a flow rate in correspondence with the cross sectional ratio of both side pressure chambers (4a, 4b), whereby the hydraulic cylinder (4) can be operated to the extension and retraction sides at the same speed.

Hydraulic circuit for working vehicle

Abstract: A hydraulic circuit for a loader vehicle includes a working machine hydraulic circuit, a steering hydraulic circuit, a variable displacement auxiliary hydraulic pump, in which the displacement volume becomes smaller as the operating oil pressure becomes higher, when the operating oil pressure exceeds a predetermined oil pressure by receiving the operating oil pressure of the working machine hydraulic circuit, and a flow dividing valve for switching and supplying oil discharge from the auxiliary hydraulic pump to either one of the hydraulic circuits with a priority being given to the steering hydraulic circuit. A pump capacity control device includes a working machine hydraulic actuator, a working machine hydraulic pump, a steering pump, a steering pump capacity servo, a working machine load sensor, and an engine speed sensor.

Active system and method for vibration and noise reduction

Abstract: An active mount is provided for use in a rotary wing aircraft between each of the gearbox and airframe mounting locations for mechanically suspending the airframe from the gearbox. The active mount comprises first and second linear hydraulic actuators each having a principal axis. The length of the actuators is variable along the principal axis for providing relative movement between the airframe and the gearbox. The principal axes of the actuators are adapted to lie in the directional planes of the primary forces necessary for supporting the airframe and acting on the transmission gearbox mounting locations for providing movement of the gearbox relative to the airframe in the planes at a frequency for reducing the transfer of vibration through the active mount to the airframe. A system for reducing vibration in the rotary wing aircraft further comprises a hydraulic system for supplying a controlled flow of pressurized hydraulic fluid to the actuators.

Low power miniature hydraulic actuator

Abstract: Electrohydraulic actuators and associated methods are utilized to control the operation of downhole well tool assemblies, representatively flow control devices In a described embodiment thereof, each actuator is positioned downhole and comprises a self-contained, closed circuit hydraulic system including an electrically operable double action primary pump drivingly coupled to an associated well tool assembly via a first hydraulic circuit, and an electrically operable switching pump coupled to the first hydraulic circuit via a second hydraulic circuit interposed therein and operative to selectively alter the control flow of hydraulic fluid to the well tool assembly in a manner reversing its operation To provide for selective, more rapid control of the well tool assembly, a chargeable accumulator is connected to the hydraulic circuitry and is selectively and drivably communicatable with the well tool assembly

Ground-surface adaptation device for attachments on harvesting machines

Abstract: The invention relates to a device for adapting attachments on harvesting machines to the ground surface, in particular for combine harvesters and forage harvesters. The aim of the invention is to produce a rapid adaptation to the ground surface, even at high speeds, that is extremely accurate and also cost-effective. To achieve this, a feed device (1), whose height can be adjusted by a hydraulic cylinder (5), has a shaft (7) which is aligned transversally to the direction of travel, the attachment (15) being mounted so that it can be rotated through a defined pivoting angle (9) about said shaft. The pivoting angle (9) can be modified by means of a hydraulic working cylinder (10) which connects the feed device (1) and the attachment (15), whereby the pivoting angle (9) is continuously monitored by a sensor (11). An additional sensor (18) continually measures the distance (17) of the attachment (15) to the ground surface. Both sensors (11; 18) are connected to the hydraulic systems of the hydraulic cylinder (5) and the hydraulic working cylinder (10) via a controller (40).

Method for boosting hydrocarbon production

Abstract: An apparatus and method that uses the local raw water injection equipment to use the minimally processed seawater as the hydraulic power fluid for the downhole turbine/pump arrangement. In one embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in an open loop arrangement. The raw water is co-mingled with the production fluids. In another embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in a closed loop arrangement. The raw water is not co-mingled with the production fluids. In another embodiment, the raw water provides hydraulic power to the downhole equipment via the production well annulus in an open loop downhole arrangement. The raw water discharged from the turbine is conveyed to a suitable formation for injection via a dual completion well.

Hydraulic Power Steering System Design and Optimization Simulation

Abstract: Hydraulic rack and pinion power steering system is a high This increases the differential pressure acting on the power bandwidth servo with stringent performance requirements piston and yields the desirable hydraulic power assist force. on accuracy, reliability, and cost. Design of such a system An optional speed sensitive steering controller modulates can be best achieved by using a validated and user friendly the fluid flow rate drawn by the RSV from the supply line, computer simulation program. Hydraulic integrated power using signals from wheel speed sensors and wheel torque steering ( HIPS ) program has been developed using basic sensor. The driver’s steering effort is increased by lowering concepts from science and engineering. HIPS provides a the hydraulic power assist during highway driving, hence design and test environment for the integrated steering and improving driver’s feel of the road during city and highway suspension system subjected to disturbance forces, which driving. The steering torque is obtained when the rack force may be induced by pump flow oscillations and tire loads. is applied to an off-center joint on the knuckle, which turns Two real-world automotive hydraulic steering systems are about the kingpin at the suspension strut, including a coil simulated with HIPS. The simulation results agree closely spring and damper assembly. with the dynamometer test results. The application of HIPS for design optimization is also demonstrated. The hydraulic power assist level, which is proportional to the diverted amount of fluid flow rate from the supply line INTRODUCTION by the RSV, is controlled by the relative angle between the steering wheel and pinion angles. This valve relative angle, Figure 1 shows a hydraulic rack and pinion power steering which is also called valve error angle, is equal to the twist system, which is a high bandwidth nonlinear servo capable angle of the torsion bar. The torsion bar is connected to the of generating a rack force of 4,000 N for cars and 6,000 N steering wheel intermediate shaft and the pinion at its top for small trucks. About 80% of the rack force comes from and bottom ends respectively. Torsion bar stiffness yields hydraulic power assist and the remaining 20% comes from the driver’s steering effort, and is designed to let the driver driver’s effort. At on-center position of the steering wheel, to turn the steering wheel with ease, and at the same time, a vane pump, which is driven by the engine, circulates the to give a memory function for the RSV in order to reduce fluid in a closed -loop hydraulic circuit which includes a the error angle towards zero, after the end of the driver’s reservoir, vane pump with flow control and pressure relief, steering demand. Since the RSV is a servo valve, during supply and return lines, and the rotary spool valve ( RSV ). on-center operation, it generates an opposing rack force to The flow control valve which connects the discharge and power piston motion subjected to tire shock and vibration inlet manifolds of the vane pump, regulates the pump flow loads. rate into the supply line at 2.1 gpm for cars and 3.5 gpm for small trucks, for engine speeds above 900 rpm. When Figure 2 shows a simplified schematic of the RSV and its the steering wheel is turned by the driver, RSV diverts the valve profile curves for two operating conditions. In valve supply line fluid flow to either side of the power piston for operating condition 1, occurring during parking, the valve a right or left turn of the vehicle. At the same time, RSV error angle is large, and valve gain, which is proportional passes an equal amount of fluid flow from the other side to the slope on the profile curve is high. As shown on the of the power piston through the return line to the reservoir. related valve profile curve, any oscillatory rack motion resulting from oscillatory pump flow rates induces a high Two real-world examples are studied with HIPS. Example 1 amplitude oscillatory pressure wave in the power cylinder is related to the front-end mechanical noise generated when of the steering gear. When this pressure wave excites the a car is driven at low speed on a bumpy road. Example 2 is structural modes at the support frame, steering shudder related to the steering wheel dither generated when a small occurs. Test results clearly show that the higher the slope truck with an unbalanced tire is driven at a certain speed on of the valve profile curve at the operating point, the more the highway. the intensity of shudder. In valve operating condition 2 occurring during city and highway driving, any oscillatory MODELING rack motion caused by tire shock and vibration loads will be opposed by the hydraulic force resulting from the servo The most important requirement in modeling a system is the action of the rotary spool valve. This causes the formation complete understanding of the performance specifications, of oscillatory pressure waves in both power cylinders. But physical and operational characteristics of each component the valve gain is low, and hence this pressure wave may in the system. The hydraulic rack and pinion power steering not have sufficient intensity to generate shudder. system of an automotive vehicle consists of hydraulic fluid lines, RSV, vane pump including flow control and pressure The steering system noise, vibration, and harshness(NVH) relief valves, power actuator, inner and outer tie rods, lower related problems occur from dynamic interaction between and upper control arms, suspension struts, front and rear roll the steering gear and suspension systems subjected to the stabilizers, disturbances such as engine torque pulsation and disturbances, such as engine torque pulsation, tire shock tire loads. A logical modularization of the integrated system and vibration loads. These NVH problems include: into steering gear and suspension component modules, and 1) Steering shudder; resulting from the excitation of the establishment of state variables with initial conditions in each fundamental frequency at the frame support by a fluid module, are determined to avoid integration blow-up and periodic flow force caused by the engine-driven vane achieve correct interpretation of simulation results. This is a pump. required method, since the integrated model of the real-world 2) Steering wheel nibble; resulting from the excitation of system under consideration consist of nonlinear components the fundamental frequency of the rack and pinion gear with discontinuous behavior. Figure 3 displays the modeling mechanism by a periodic rack force induced by brake architecture of the HIPS simulation program. disk roughness, during braking at highway speeds. 1) Steering Gear Model. 3) Mechanical front-end noise; resulting from the dynamic Figure 4 shows the hydraulic power steering model which interaction between the rack and steering gear housing, consists of the following component models: caused by tire shock and vibration loads generated by a) Closed-loop hydraulic circuit; including vane pump, tires riding on the bumps, stones, and pot holes on the flow control valve with pressure relief, tuned supply road during low speed driving. and return lines, cooler, reservoir, and RSV. 4) Steering wheel dither; caused by dynamic interaction b) Power actuator; including the steering wheel, torsion between the steering gear and front suspension struts bar, pinion gear, rack spring preload, power piston, subjected to a periodic vertical tire load induced by a tie rods, knuckle, tires, and housing. tire high spot at a certain highway speed. c) Driver commands for applying steering angle, steering rate, and engine rpm profiles. Present solutions for steering system NVH problems d) Disturbances; including pump flow rate oscillations and mentioned above, are usually achieved by using tuned tire shock and vibration loads, which occur when driving hoses, shorter or longer hoses in the hydraulic lines, on a rough terrain or with tire high spots on a highway. passive and active dampers, and reducing the RSV gain. Since, all of the above solutions are based on empirical The steering gear model is obtained by applying fundamental rules, their adaptation to new car platforms would be laws from fluid dynamics, heat transfer, and dynamics. The time consuming and expensive. But, these solutions may state variables are described by linear and nonlinear ordinary cause an increase in power losses, and a reduction in the ordinary differential equations, with discontinuous behavior steering system bandwidth. The steering system NVH and temperature-dependent parameters. related problems are solved best, by using a validated 2) Suspension Model. and user-friendly computer simulation program. The Figure 5 shows an 4-wheel independent suspension system hydraulic integrated power steering ( HIPS ) simulation consisting of the following component models: program consists of two modules: Module 1 contains a) The sprung mass frame, with three degrees of freedom; the steering gear model, and Module 2 contains the heave, roll, and pitch. suspension model. b) Four unsprung masses, each with heave motion. c) Four suspension struts. Each strut consists of a c) Optimization Test. coil spring and a nonlinear damper. Each strut is The system parameters representing torsion bar stiffness, connected between the movable end of the lower rack spring preload, and bushing stiffness at the housing control arm and a corner of the frame or the upper supports of the steering gear have been changed, one at control arm. Each control arm is pivoted about a a time, and corresponding simulation runs were carried rubber bushing connected to the frame. This gives out to obtain responses for XRK3MM and ZRK3MM. heave motion degree-of-freedom to the tire. Each The main goal of this study was to reduce the amplitude strut is tilted with respect to vertical direction, as of above responses, without degrading the steering fe

Hydraulic grain storage bin lifting system and method

Abstract: The present invention is a method for constructing cylindrical grain bins. The method employs a sets of identical, telescoping jacks actuated by hydraulic cylinders and an hydraulic system having separate hydraulic circuits that serve each set of jacks. Using the set of identical, hydraulic, telescoping jacks, successive rings of a grain bin structure made up of connected panels are lifted. After a first ring is lifted, a second ring can be attached to the lower edge of the first ring. The second ring is then lifted and the process is repeated until the grain bin is completed.

Electro-hydraulically pressurized downhole valve actuator and method of use

Abstract: A petroleum well having a communication system and a hydraulic system is provided. The petroleum well includes a borehole and a piping structure positioned within the borehole. The communication system supplies a time varying electric current downhole along the piping structure. The hydraulic system, which is positioned downhole proximate the piping structure, receives the time varying current to operate an electric motor. The motor drives a pump which pressurizes hydraulic fluid to selectively drive an actuator. The actuator is operably connected to a downhole device, such as a shutoff valve, and operates the downhole device as the actuator is driven by the pressurized hydraulic fluid.

A new robust sliding mode controller for a hydraulic actuator

Abstract: We present the design of a robust sliding mode controller for the force control of a hydraulic actuator in presence of significant system nonlinearities and uncertainties. Our control strategy is based on sliding mode control. The design of a switching surface is based on Lyapunov techniques, and a variable structure control law is designed using the theory of sliding mode control. For the control we use a nonlinear mathematical model of a hydraulic system interacting with the environment. We try and consider most of the nonlinear and uncertain dynamics of this system in order to achieve robust performance over a range of operating conditions. The simulation results show that the proposed sliding mode controller is not sensitive to a large variation of parameters such as flow gain, supply pressure or environmental stiffness, and has an excellent tracking performance for various set point forces under uncertainties.

Drive device for a machine with a traction drive system and a hydraulic work system

Abstract: A drive device is provided for a machine with a traction drive system and a hydraulic work system. The traction drive system has a drive axle and the hydraulic system has at least one electric motor and at least one pump driven by the electric motor. The electric motor and/or the pump are integrated into the drive axle or are located directly on the drive axle. In one configuration, the drive axle has two traction motors located on the ends of the drive axle. The electric motor and/or the pump are located axially between the traction motors. Downstream of the pump of the hydraulic work system there is a valve control device which is integrated into the drive axle or is fastened to the outside of the axle housing in the vicinity of the pump.

Hydraulic device for industrial vehicles

Abstract: A hydraulic device for industrial vehicles. A first motor drives a first hydraulic pump and a second hydraulic pump. The first hydraulic pump supplies hydraulic fluid to a power steering device and a brake device. The second hydraulic pump supplies hydraulic fluid to a carriage device. If an increased amount of hydraulic fluid need be supplied to the carriage device, a second motor drives a third hydraulic pump. Thus, together with the second hydraulic pump, the third hydraulic pump supplies hydraulic fluid to the carriage device.