620 results about "Variable displacement pump" patented technology

A hydraulic system is provided having a reservoir configured to hold a supply of fluid. The hydraulic system also has a variable displacement pump configured to supply charge fluid and pilot control fluid to the hydraulic system. In addition, the hydraulic system has a closed-loop portion configured to receive charge fluid from the variable displacement pump and drive a mechanism. The hydraulic system further has a pilot fluid supply portion configured to direct pilot control fluid from the variable displacement pump to closed-loop portion.

A Zero Turn Radius vehicle is provided that utilizes a drive system including a single hydraulic variable displacement pump and dual variable displacement hydraulic motors connected respectively one to each of two ground engaging wheels for use in steering and propelling the vehicle. The configuration of the drive system allows for proper ZTR steering of the in the forward and reverse directions.

A variable displacement oil pump for an automotive engine. The oil pump includes a cam ring accommodating thereinside a pump element having a rotor. The cam ring is swingingly movably accommodated in a housing and biased in a direction to increase an eccentricity amount of the cam ring relative to the axis of the rotor by a biasing member. First and second pressure chambers are defined inside the housing by the outer peripheral section of the cam ring. The first pressure chamber is supplied with a discharge pressure to be applied to the cam ring to oppose to a biasing force of the biasing member. The second pressure chamber is supplied with the discharge pressure to be applied to the cam ring to assist the biasing force of the biasing member. Additionally, a control device is provided for controlling supply of the discharge pressure to the second pressure chamber.

A pump chamber 18 is formed between a cam ring 17 and a rotor 15 in a pump body 11. The cam ring is formed so as to move to direction that pump capacity of the pump chamber increases and decreases. A first and second fluid pressure chambers 33 and 34 are formed at both sides of moving direction of the cam ring 17. The pump has a spool operates to axis direction by difference in fluid pressure of upper and lower stream sides of a metering throttle 50 formed on a way of a discharge side passage 27 of the pump chamber and provides at least a control valve 30 controlling fluid pressure in the first fluid pressure chamber. An electronic driving unit applying thrust to axis direction to the spool of the control valve, for example, a solenoid 60 is provided.

A control system for a variable displacement pump. The control system is operably associated with an engine control unit for passively or actively controlling the output of the pump in response to signals from the engine control unit.

Apparatus, system, and method for controlling a desired torque output on a hydromechanical transmission. Controlling torque output of a hydromechanical transmission provides improved operator feel and control. A control module determines a desired torque output and determines a pressure necessary to influence the displacement of the variable displacement pump to output the desired torque output. A pressure-controlling valve applies that amount of pressure to an actuator, which moves in response thereto, to change the displacement of the variable displacement pump. When the motor speed changes, the control module adjusts the pressure applied to the actuator to provide the desired torque output.

A pump including a pump chamber 18, formed in a pump body 11, between a cam ring 17 and a rotor 15. The cam ring is formed so as to move in a direction whereby the pump capacity of the pump chamber increases and decreases. First and second fluid pressure chambers 33 and 34 are formed at opposite sides of the cam ring 17. The pump has a spool that is axially moved by a difference in fluid pressure between upper and lower stream sides of a metering throttle 50 connected to a discharge side passage 27 of the pump chamber. The spool is part of a control valve 30 that controls fluid pressure in at least the first fluid pressure chamber. An electronic driving unit, for example, a solenoid 60, applies axial thrust to the spool of the control valve.

A system and method for controlling the movement of an implement of an earthmoving machine. The system includes a hydraulic actuator adapted to move the implement. A variable displacement pump is coupled to the actuator for delivering a pressurized fluid to and receiving pressurized fluid from chambers within the actuator. A sensor generates an output based on the position of the actuator's piston or piston rod, and a controller controls the displacement of the variable displacement pump in response to the output of the sensor by executing an algorithm to reduce the flow rate of the fluid to and from the actuator's chambers and thereby reduce the velocity of the piston as it approaches an end of a piston stroke thereof and prevent the piston from impacting the actuator at the end of the piston stroke.

A control device controls a hydrostatic transmission vehicle having a hydrostatic transmission including a variable displacement pump and a variable displacement hydraulic motor. The control device is configured to set a set vehicle speed based on a forward / rearward travel command and a gear stage command instructed by an operator, to set a torque limit usable for the hydrostatic transmission based on an engine speed, to set a vehicle speed limit based on a pressure in the hydraulic circuit and the torque limit, to select a lower one of the set vehicle speed and the vehicle speed limit, and to control respective displacements of the variable displacement pump and the variable displacement hydraulic motor based on the selected vehicle speed.

A variable displacement pump includes a pump structural member configured to change volumes of a plurality of working chambers by rotation of a rotor, so as to introduce oil through an inlet port into the working chambers and to discharge the oil through a discharge port, and further configured to oscillate a cam ring by a discharge pressure introduced into a control oil chamber. A first coil spring is provided to force the cam ring in a direction for increasing of a rate of change of the working-chamber volume. A second coil spring is provided to force the cam ring in a direction for decreasing of the rate of change of the working-chamber volume. The first and second coil springs are laid out on both sides of an arm portion of the cam ring in a manner so as to be opposed to each other.

The system includes a hydraulic surface actuator for operating a piston coupled to a structural member of an aircraft for moving the structural member. An electrical feedback sensor is coupled to the actuator piston rod. A summing circuit for receiving a command signal and the feedback signal is provided having an output which is coupled to a loop gain compensator for operating a servo motor. The shaft of the servo motor drives the shaft of a variable displacement pump having ports leading to the ports of the actuator. The variable displacement pump has a swash plate the angle of which is reduced by a hinge moment sensor and a de-stroking actuator when the load on the surface actuator exceeds a given percentage of maximum. A pump gain sensor measures the reduction in pump gain and produces an electrical output which is applied to the loop gain compensator to compensate for reduction in pump gain.

A cam ring 10 is slidably supported within a pump body 2, and a rotor 20 is rotatably disposed inside the cam ring. The cam ring is eccentric to a rotation shaft 22 of the rotor. The rotor carries a plurality of vanes 18 that can be advanced or retreated, in which a pump chamber 24 is formed in a space between the cam ring and the rotor. The cam ring is formed with the first and second fluid pressure chambers 14 and 16 on both sides thereof, and biased in a direction where the displacement of the pump chamber is at maximum by a spring 26. A control valve 28 is provided in which a differential pressure across a metering orifice is applied on both ends of a spool 32 and a spring 36 is disposed on the side of an end face where a downstream fluid pressure is applied. The fluid pressures of the fluid pressure chambers 14 and 16 are controlled by means of the control valve, whereby the cam ring is swung. A piston 58 that is moved in accordance with an increase in working pressure of a power steering apparatus is provided. This piston 58 exerts an axial thrust to an end face of the spool on the spring side.

Systems and methods for controlling and actuating actuators that perform multiple functions in a machine. Such systems and methods encompass a hydraulic system adapted to control and actuate the actuators of the machine. The hydraulic system includes variable displacement pump / motors connected to the engine in parallel. A first of the pump / motors controls a first of the actuators, and a second of the pump / motors is adapted to draw power from and deliver power to the engine and the first actuator, as well as control at least a second of the actuators. An energy storage device is connected in series with the second pump / motor and the second actuator, and accumulates a fluid pumped thereto by the second pump / motor, as well as delivers the fluid to the second pump / motor, depending on whether the second pump / motor delivers is delivering or drawing power from the engine or first actuators.

A variable displacement pump includes: a first control oil chamber which moves a cam ring toward a direction against a biasing force of a biasing member when a discharge pressure is introduced thereinto; a second control oil chamber which acts a hydraulic pressure upon the cam ring by cooperating with the biasing force of the biasing member when hydraulic oil is introduced thereinto; a switching mechanism which switches between one state in which hydraulic oil whose pressure is decreased than a discharge pressure is introduced to the second control oil chamber from the discharge section and another state in which hydraulic oil is discharged from the second control oil chamber; and a control mechanism operated before an eccentricity of the cam ring becomes a minimum and which discharges a greater amount of hydraulic oil within the second control oil chamber as the discharge pressure becomes larger.

A Zero Turn Radius vehicle is provided that utilizes a drive system including a single hydraulic variable displacement pump and dual variable displacement hydraulic motors connected respectively one to each of two ground engaging wheels for use in steering and propelling the vehicle. The configuration of the drive system allows for proper ZTR steering of the in the forward and reverse directions.

A load control structure for a work vehicle comprises: a device for detecting operating position of a manually operated speed change operating element; an engine load detection device for detecting load on an engine of the work vehicle; a swash plate position detecting device for detecting an operating position of a swash plate of a variable displacement pump of a hydrostatic continuously variable speed change device; a pump operating device for steplessly operating the swash plate of the variable displacement pump; a motor operating device for operating a swash plate of a variable displacement motor of the hydrostatic continuously variable speed change device between at least two speed change positions including a higher speed position and a lower speed position; a control device for controlling the operations of the pump operating device and the motor operating device. The control device has a automatic pump swash plate control device for controlling the operation of the pump operating device, based on detected information from the load detection device and detected information from the swash plate position detecting device, such that the greater an engine load is, greater is the extent to which the swash plate of the variable displacement pump is operated to a low speed side; and a motor swash plate control device for controlling the motor operating device so as to change the position of the swash plate of the variable displacement motor between the at least two speed change positions.

The invention discloses an energy-saving shield machine hydraulic pressure control system, adopting hydraulic transformer, which comprises a hydraulic transformer, a motor, a constant pressure variable displacement pump, a two-position three-way reversing valve, a proportional overflow valve, a safety valve, an accumulator, a hydraulic cylinder, a three-position four-way reversing valve, a hydraulic motor, a reducing valve and a two-position two-way reversing valve; wherein, the shield machine driving, the cutter head drive and the spiral transportation system are integrated in a loop; the constant pressure network comprising the constant pressure variable displacement pump and the accumulator provides the system with power energy; the propulsion system adopts group control and comprises a plurality of groups; the discharge capacity of variable displacement pump / motor inside the hydraulic transformer is adjusted in real-time to control the speed and the propulsive force of the propulsion hydraulic cylinder and the rotational speed and the output torque of the hydraulic motor. The energy-saving shield machine hydraulic pressure control system has the advantages of adopting hydraulic transformer and other energy-saving elements and control methods, lossless transfer of energy, guarding against energy loss in the throttling speed regulation system, and good performance of energy-saving.

The invention discloses an energy-saving control system and an energy-saving control method for an automobile crane. The energy-saving control method comprises the following steps of: providing the flow required by a hydraulic system of the automobile crane through a handle and detecting the load pressure of the hydraulic system through a pressure sensor; calculating or searching the minimum value of oil consumption in unit time of the engine under the current load within the set change range of the current rotating speed by utilizing an energy-saving algorithm module; and adjusting the engine to rotate at a rotating speed corresponding to the minimum value of the oil consumption in unit time, and adjusting a variable displacement pump of the hydraulic system to have the displacement matched with the rotating speed. The invention also discloses an automobile crane with the energy-saving control system. In the invention, the handle directly corresponds to the flow of the hydraulic system, and the joint control of the rotating speed of the engine and the displacement of the variable displacement pump is realized.

The present invention is a method and system for controlling a motor attached to a variable displacement pump for providing a supercritical fuel and fuel pressure to a plurality of fuel injectors of a vehicle engine. The system includes: a pump having a motor; a tachometer sensor for measuring a rotational displacement of a motor shaft and for sending a tachometer count value to a memory device; an engine control unit configured to generate a rotational displacement vs. pressure profile of the pump based on the displacement value and pressure value; an accumulator attached to the output of the pump; and a control method that allows for a look ahead and prediction of the pump requirements needed in a future cycle based on current demand to allow for an efficient fuel injection pump.

A method of reducing speed in a hydrostatic drive work machine, and a hydrostatic drive work machine are provided. The method includes the steps of retarding the work machine by at least one of, upstroking a variable displacement hydraulic motor thereof, and downstroking a variable displacement pump coupled with the motor. An offgoing clutch pressure is dropped after each of the motor and pump displacements reaches a predetermined point. The steps of slowing the work machine are carried out by adjusting the respective displacements at rates based on a predetermined acceleration limit and / or a predetermined jerk limit of the work machine. The hydrostatic drive work machine further includes an electronic control module having a control algorithm recorded thereon for to neutral.

A variable displacement pump includes: an urging mechanism which includes two spring members; an electromagnetic switching valve which is arranged to connect the second control chamber and the discharge portion in an energized state, and to connect the second control chamber and the low pressure chamber in a deenergized state; and a control valve which is actuated by the pressure of the discharge portion, and which is arranged to decrease the pressure within the second control chamber when the pressure of the discharge portion becomes equal to or greater than a predetermined pressure.

The invention discloses a pump / motor-based parallel-series hybrid hydraulic excavator driving system, which comprises a movable arm driving cylinder, a mounting mechanism, an electric quantity storage unit, a hydraulic control element, a group of other actuating mechanism consisting of a bucket cylinder, a bucket arm cylinder and a travel hydraulic motor, an engine, a first motor and a variable displacement pump which are in coaxial mechanical transmission connection with the other actuating mechanism, and a second motor, a pump / motor, an electromagnetic clutch and a speed reducer which are in coaxial mechanical transmission connection with the mounting mechanism. The displacement pump is connected to the other actuating mechanism through a hydraulic main control valve; the first motor iselectrically connected with the electric quantity storage unit; the second motor is electrically connected with the electric quantity storage unit; the hydraulic control element is communicated with oil circuits of the movable arm driving cylinder, a parallel hybrid system, a series hybrid system and the other actuating mechanism. The efficiency of an energy recovery system is improved, the flowing flexibility of recoverable energy and the diversity of control modes are increased, and the cost is reduced.

The present invention is a variable displacement pump having an inner rotor rotatable about a first axis and having at least two slots. The pump also has at least two vanes, each located in a distinct one of the at least two slots. The pump also has an outer rotor rotatable about a second axis, operably associated with the inner rotor, the outer rotor having two or more recesses, each configured to receive one of the vanes. The pump also includes an expandable chamber formed by the outer rotor and the inner rotor, an eccentric ring surrounding the outer rotor, and a housing. The eccentric ring is located within the housing for adjusting the relative relationship between the first axis and the second axis in order to vary the displacement of the pump.

Hydraulic system for driving an auxiliary power source is provided, which is specifically adapted for use with a system for controlling hydraulically driven AC generator. The system includes a hydraulic pump and hydraulic motor that are connected by a fluid circuit. The hydraulic motor drivably connected to an AC generator and is operated in a manner to generate a stable AC power output. The system may include a valve which bypasses fluid around the motor or a variable displacement pump so that the fluid flow rate through the hydraulic motor is controlled in a manner to maintain the desired AC generator output level. Sensors are further provided measuring operating parameters of the system so that the controller can maintain desired operating condition limits

An object of the present invention is to provide a hydrostatic transmission system integrally constructed without being large-sized while incorporating a variable displacement motor therein. In order to accomplish the object, a casing 11 has a variable displacement pump 1 and a variable displacement motor 3 incorporated therein in a manner to be juxtaposed to each other. The pump 1 is constituted by a cam plate type axial plunger pump which is constructed so as to render a tilting angle of a cam plate 18 variable and render a discharge rate of hydraulic fluid zero when the tilting angle is within a range set near 0 degree. The motor 3 is constituted by a cam plate type axial plunger motor including a cam plate 33 of which a tilting angle is variable. A cover 48 is provided with a pair of passages 2a and 2b, relief valves 9a and 9b, check valves 10a and 10b, and a change-over valve 5.

A fuel metering unit for controlling a variable displacement pump including a main metering valve in fluid communication with the pump for metering an output of the pump, a pressure regulator in fluid communication with the metering valve to create a spill return and a control valve in fluid communication with the pressure regulator and the pump for regulating the spill return flow so the spill return flow is maintained substantially constant at a low level to minimize the heat generated by recirculation by setting a displacement of the pump.

A variable displacement pump includes an urging mechanism to urge a cam ring in an eccentric direction and to increase the urging force when an eccentricity is decreased, a first control chamber to apply a force to the cam ring in a direction decreasing the eccentricity, and a second control chamber to apply a force, to the cam ring, in a direction increasing the eccentricity. The variable displacement pump further includes a thermosensitive mechanism to control the supply and drain of a discharge pressure supplied into the second control chamber, and a control valve to be operated by the discharge pressure and to decrease the pressure in the second control chamber when the discharge pressure increases.