Abstract: A hydraulic drive apparatus includes a flow-path selector valve and a flow-path switching control unit that operates the valve. The flow-path selector valve has a first position for a single operation state and a second position for a combined operation state, configured to, at the first position, form a first flow path connected to a first pump, a second flow path connected to a second pump, and a connecting flow path providing communication between the first flow path and the second flow path. When a driving state of a work actuator is deviated from an allowable range in the combined operation state, the flow-path switching control unit reduces an opening area of the connecting flow path as compared with that when the driving state is within the allowable range.

Abstract: A hydraulic rotating machine includes a case, a cylinder block housed in the case and having a plurality of cylinders, a piston reciprocatively inserted into the cylinder; a swash plate configured to reciprocate the piston as the cylinder block rotates, a tilt control piston configured to biase the swash plate and control a tilt angle of the swash plate, and a stopper mounted to the case, the stopper being configured to define a minimum tilt angle of the swash plate. The stopper has a sliding surface for slidably supporting the tilt control piston.

Abstract: Provided is a hydraulic drive apparatus including a specific working actuator making a working arm perform a traveling assist motion upon the slip, first and second traveling motors, first and second hydraulic pumps, a traveling selector valve switchable to a neutral position and a straight traveling position, a communication throttle portion between a working fluid passage and a traveling fluid passage in the straight traveling position, and a switching control part switching the traveling selector valve to the neutral position when a single operation action is performed and to the straight traveling position when a specific combined operation action including a forward traveling operation and the specific working operation is performed. The switching control section adjusts the opening of the communication throttle section to decrease the flow rate therethrough with an increase in the difference between the first and second pump pressures.

Abstract: A work vehicle provided with a loading hydraulic circuit (A), including at least a main hydraulic pump (31), a lift arm cylinder (8) and a control valve (32), an auxiliary hydraulic pump (31), a negative parking brake device (PB), and a parking brake releasing hydraulic circuit (B2), in which the vehicle includes: a loading operation hydraulic circuit (B1) located upstream of the parking brake releasing hydraulic circuit; an emergency flow path (80) for supplying the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device through the loading operation hydraulic circuit in an emergency; and a valve unit (81) located in the emergency flow path. If the pressure of the parking brake releasing hydraulic circuit is lower than the brake release pressure to release the braking state of the parking brake device, the valve unit is switched to the communicating position.

Abstract: Control systems and feedback assemblies for hydraulic axial displacement machines, such as pumps and motors. The control systems and feedback assemblies can reduce friction on the charging spools and provide for a more reliable return of the swashplate to a neutral position. Aspects of the control systems and feedback assemblies can be modularized for, e.g., easy maintenance and to reduce the overall size of the system.

Abstract: Displacement control device for providing pressure fluid to a servo unit for adjusting the displacement of a pressure fluid unit, having a control cylinder in which a control spool is mounted shiftable along the longitudinal axis of the control cylinder, an inlet port, a servo port and a discharge port are formed in the control cylinder longitudinally spaced from each other, wherein the control spool comprising: a basically cylindrical outer surface; a front face on which an actuation force can act for shifting the control spool along the longitudinal axis; a discharge area opposite to the front face; a longitudinal bore inside the control spool, wherein one end of the longitudinal bore opens towards the front face and the other end is connected via a backpressure orifice with the discharge area; a control recess provided lengthwise in the outer surface; a radial bore which connects via a flow limiting orifice the longitudinal bore with the outer surface, wherein the opening of the radial bore at the outer su

Abstract: A compressed air supply installation for operating a pneumatic installation, especially an air suspension installation of a vehicle, includes a compressed air supply unit, a compressed air port towards the pneumatic installation, a venting port towards the surroundings, a first pneumatic connection between the compressed air supply and the compressed air port, the first pneumatic connection having an air drier and a shut-off valve, and a second pneumatic connection between the compressed air port and the venting port. The shut-off valve is a pneumatically pilot-controlled check valve.

Abstract: A hydraulic system includes first and second control valves controlling a flow rate of operation fluid to be supplied to first and second hydraulic actuators, respectively, a supply fluid tube connecting the first control valve and the second control valve and being connected to a return fluid tube, and a discharge fluid tube connected to the second control valve. The second control valve is switched between primary, secondary, and tertiary positions, the primary position blocking between the supply fluid tube and the discharge fluid tube and allowing return fluid to be supplied to the second hydraulic actuator, the secondary position communicating between the supply fluid tube and the discharge fluid tube and stopping supplying the return fluid to the second hydraulic actuator, and the tertiary position communicating between the supply fluid tube and the discharge fluid tube and allowing the return fluid to be supplied to the second hydraulic actuator.

Abstract: The present invention relates to a hydrostatic transmission system comprising: at least one pump (110), at least two wheel motors (120, 122; 140, 142) supplied by the pump (110) for the mechanization of a machine, characterized by the fact that it comprises means (130) designed to offset in time a change of displacement of the motors (120, 122; 140, 142) into several groups so as to have a progressive evolution of the apparent displacement of the motors.

Abstract: A lubrication pumping system for an oil lubricated engine is provided that includes a pump with an outlet and inlet. A relief valve is included having a housing with a multidimensional bore having a first diameter section axially intersecting with a second different diameter section. Slidably mounted in the first section is a spring biased primary piston have a first landing for metering flow between a pump discharge connection and a pump inlet connection. A secondary piston is provided in a second different diameter section of the valve housing bore. The inventive system allows for multiple modes of operation of oil pressure versus engine speed relationships by control of the pilot pressure to minimize parasitic loads exerted by the oil pump on the vehicle engine.

Abstract: Hydrostatic adjusting device of a hydraulic machine, the swept volume of which can be adjusted by way of a servo adjusting unit, having a control unit which has a control cylinder which has at least one inlet for pressurized hydraulic fluid, at least one servo connector for a connecting line to the servo adjusting unit, and at least one outlet to a hydraulic fluid collecting region. A control piston is arranged in the control cylinder, which control piston can be displaced by means of at least one control piston actuator and has control edges. In interaction with control edges which are configured in the control cylinder, the inlet or the outlet can be alternately connected hydraulically to the connecting line, whereby the pressure which prevails in the connecting line can be returned hydraulically via a control line to at least one end side of the control piston.

Abstract: The present invention relates to a hydraulic control system for construction machinery capable of variably adjusting a set pressure of a relief valve, which controls a set pressure of a hydraulic system, according to a value inputted by means of pressure in the hydraulic system or the manipulation of a joystick.

Abstract: A transaxle comprises a hydrostatic transmission (HST), an axle, a gear train interposed between the HST and the axle, a casing and a partition. The casing defines an HST chamber and a gear chamber. The HST is disposed in the HST chamber. The gear train and the axle are disposed in the gear chamber. The partition is disposed in the casing so as to separate the HST chamber and the gear chamber from each other. The partition has an opening through which a hydraulic motor of the HST passes to extend from the HST chamber into the gear chamber so as to be drivingly connected to the gear train. The partition obstructs a flow of fluid between a fluid sump in the HST chamber from a fluid sump in the gear chamber.

Abstract: A slewing-type working machine includes: a slewing motor which is a hydraulic motor for slewing; a variable-displacement hydraulic pump; a slewing operation device including an operation member; a control valve controlling the slewing motor based on an operation signal thereof; a pump regulator; a relief valve letting excess fluid to a tank; operation detectors detecting an operation direction and amount of the operation member; a motor rotational speed detector; and a controller controlling a discharge flow rate of the hydraulic pump. The controller obtains a deviation between a target rotational speed of the slewing motor obtained from a slewing operation amount and an actual rotational speed detected by the motor rotational speed detector, and controls the discharge flow rate to make the deviation closer to 0.

Abstract: The invention provides a rotation control device capable of reducing a loss of a power of a hydraulic pump in a backward direction operation and also provides a construction machine including the same. The controller controls a capacity of the hydraulic pump such that, in a forward direction operation in which an operating direction detected by the operation sensor and a rotating direction detected by a rotation sensor coincide with each other, the capacity of the hydraulic pump is increased in accordance with an increase in the operation amount detected by an operation sensor, on the other hand, restricts the capacity of the hydraulic pump more in a backward direction operation, in which the operating direction detected by the operation sensor and the rotating direction detected by the rotation sensor are reverse to each other, than in the forward direction operation.

Abstract: A servo regulator that causes a servo piston to move on the basis of working fluid pressure in two pressure chambers includes: a sleeve that is inserted into an insertion hole formed in a case and has a supply port capable of supplying a working fluid from a fluid pressure source to one of the pressure chambers; a spool valve disposed in the sleeve so as to be biased by a biasing member; and a solenoid that is attached to the case in order to drive the spool valve via a plunger. The sleeve includes a pressure receiving portion on which a fluid pressure of the working fluid from the fluid pressure source is exerted, and is pressed against an end surface of the solenoid by a biasing force acting on the pressure receiving portion.

Abstract: In a working machine having an upper slewing body rotated by a slewing electric motor, a controller outputs a command for switching a communication valve, and a command for specifying a torque of the slewing electric motor. The controller includes an abnormal-switching detection section which detects occurrence of abnormal switching in the communication valve, wherein the controller (i) determines, as a target value, a pressure which would be generated in the hydraulic motor if the communication valve was absent, or a torque determined based on the pressure, based on an operation state of a slewing operation device and a slewing state of the upper slewing body; (ii) determines, as an actual value, a pressure actually generated in the hydraulic motor or a torque determined based on the pressure; and (iii) outputs the torque command on the basis of a value obtained by subtracting the actual value from the target value.

Abstract: A hydrostatic positive displacement machine (2) is operated in a closed circuit and delivers hydraulic fluid into a working circuit. The displacement volume is varied by a control device (6) having a variable displacement piston device (7). The machine (2) has a swivel-back device (40) which, in the event of a decrease of the feed pressure from the feed pressure source (11), guarantees actuation of the machine (2) toward a reduction of the displacement volume. The swivel-back device (40) includes at least one pressure sequence valve (41), which is in communication on the input side with the working circuit of the machine (2). In the event of a decrease in the feed pressure from the feed pressure source (11) below a limit pressure, the pressure sequence valve (41) makes it possible to supply the control device (6) of the machine (2) with hydraulic fluid from the working circuit.

Abstract: A hydraulic circuit is provided. The hydraulic circuit includes a primary pump, a displacement actuator, a charge pump, a direction control valve, and a pressure control valve. The displacement actuator is associated with the primary pump. The charge pump is configured to generate a flow of a pilot fluid. The direction control valve is configured to control the flow of the pilot fluid to the displacement actuator to affect a movement direction of the displacement actuator. The pressure control valve is configured to control a pressure of the pilot fluid to affect a movement amount of the displacement actuator. Further, the hydraulic circuit includes a controller. The controller is configured to control the direction and the pressure control valves to adjust a displacement of the primary pump based at least on one of a sensed engine parameter or a mode of operation of the primary pump.

Abstract: A multi-wheel drive system for a vehicle and a method of control. The system may include first and second inlet valves that may control the flow of fluid to a gerotor pump that may actuate a clutch to provide torque to a wheel set.

Abstract: A method of controlling a pump for a hybrid transmission includes commanding a first line pressure of the transmission and deriving a first torque value—an open-loop torque value—from the first line pressure command, and commanding the pump to operate at the first torque value. The method monitors actual speed of the pump and derives a second torque value—a closed-loop torque value—therefrom. A third torque value is derived from the first and second torque values, and the pump commanded to operate at the third torque value. A first speed value may be derived from the first line pressure command, and the second torque value derived from the difference between the monitored and the first speed values. Deriving the third torque value may include a substantially-linear combination of the first and second torque values.

Abstract: A pump displacement control cylinder is configured to control the displacement of a hydraulic pump according to pressure of hydraulic fluid and switches the discharge direction of the hydraulic fluid from the hydraulic pump according to the supply direction of the hydraulic fluid to the pump displacement control cylinder. A forward and backward progression switching valve is configured to switch the supply direction of the hydraulic fluid to the pump displacement control cylinder. A pressure control valve is configured to control the pressure of the hydraulic fluid supplied to the pump displacement control cylinder according to a command value input to the pressure control valve. A control section is configured to execute pump shuttle control which reduces the command value to the pressure control valve when switching between forward and backward progression using a forward and backward progression operation member.

Abstract: An electro-hydraulic steering system for an articulated machine includes an electrical circuit and a hydraulic circuit. The electrical circuit includes a controller, an electro-hydraulic valve assembly, and a spool position system. The hydraulic circuit includes a pump, at least one cylinder in selective fluid communication with the pump, and the valve assembly. The controller includes a computer-readable storage medium storing a steering system monitoring application which performs several steps. A desired flow of pressurized fluid to each cylinder and a desired spool position for the spool of the electro-hydraulic valve assembly, based upon the desired flow of pressurized fluid, are determined. The desired spool position and an actual spool position are compared to determine a spool-based flow error, which is summed over a period of time to determine a cumulative spool-based flow error. An event warning is issued when the cumulative spool-based flow error exceeds a threshold.

Abstract: A hydraulic pump controlling apparatus of a construction machine according to the present disclosure includes: a hydraulic pump in which a swash plate angle is controlled to control a discharge flow; an auxiliary pump; a control valve controlling a flowing direction of a fluid discharged from the hydraulic pump and selectively supplying the fluid to an actuator; an orifice and a relief valve connected between a center bypass line of the control valve and a tank T to be parallel to each other; signal pressure selecting units receiving a fluid passing through the center bypass line of the control valve and a fluid discharged from the auxiliary pump, and selecting the pressure of any one of the fluids as a signal pressure; and a regulator receiving the signal pressure selected from the signal pressure selecting units to control the swash plate angle of the hydraulic pump, and the signal pressure selecting unit selects the pressure of the fluid discharged from the auxiliary pump as the signal pressure and transfe

Abstract: A hydrostatic pump (1) with a variable delivery volume can be operated in a closed circuit. An electrically controllable actuator device (4) is provided for the control of the delivery volume of the pump (1). The electrically controllable actuator (4) has an electrically actuatable control valve device (6) which generates a positioning pressure which actuates a positioning piston device (5) which is in an operative connection with a delivery volume control device (3) of the pump. An electrical position feedback circuit (21) of the delivery volume control device (3) is provided and the actuator device (4) is provided with a switchable hydraulic neutral position control system (25), by means of which a restoring movement can be generated that acts on the positioning piston device (5) and places the delivery volume control device (3) into a neutral position.

Abstract: A method for controlling an automated clutch, which comprises a hydraulic clutch actuating system having a hydrostatic actuator, the pressure of which is detected. The method includes using the pressure of the hydrostatic actuator to adapt the characteristic curve of the clutch.

Abstract: Disclosed is a work machine having a traveling apparatus and a work implement driven by an engine. A hydraulic system mounted on the work machine includes an HST pump comprising a swash plate, variable displacement pump driven by the engine, an HST motor connected in a closed circuit to the HST pump and a pair of speed-changing oil passageways, the HST motor being driven by an amount of oil supplied by the HST pump, thereby to drive the traveling apparatus, a main pump driven by the engine, the main pump supplying pressure oil to the work implement, a pilot pump driven by the engine, a swash plate positioning circuit configured to effect positioning of a swash plate of the HST pump with pilot oil supplied from the pilot pump, and a bleed circuit configured to drain, via a throttle, a portion of the pilot oil supplied to the swash plate positioning circuit.

Abstract: A pumping system is provided which is a mobile, vehicle-mounted pumping system, such as for water or fuels, which mounts on a vehicle and may be used for various applications. The pumping system operates a drive system and control system for liquid pumps almost exclusively by hydraulic fluid pressure.

Abstract: The invention relates to a hydraulic circuit arrangement for setting the delivery volume of a pump, with an electrically activatable control-valve unit, by means of which, alternately, an active side of a servo system can be acted upon with pressure and, at the same time, its passive side can be relieved to the tank, and with a device for pressure limiting pressure regulation, which comprises pressure limiting valves, by means of which the working lines of the pump can be connected to the servo lines. To reduce the servo pressure load and improve the reaction time, check valves which shut off in the direction of the servo system are provided, by means of which the two servo sides can be connected in each case to the charge pressure via a relief line. Moreover, the device for Pressure limiting pressure regulation comprises an orifice which can be positioned in a line leading to the passive servo side. The invention relates, furthermore, to a method for pressure.

Abstract: A hydraulic control circuit for the overcontrol of a hydraulic system which controls a drive, in particular for controlling a hydraulic motor (5) for driving a slewing gear of a crane superstructure, wherein the pressure lines (3.9, 3.10) for the hydraulic motor (5) are connected by means of a supply piston (3.2) to a hydraulic pump (2) or a tank (1), and the pressure lines (3.9, 3.10) are each assigned pilot valves (3.4, 3.3), shuttle valves (3.8, 3.7) and directional control valves (3.6, 3.5). The shuttle valves (3.7, 3.8) are connected by means of control lines (3.11, 3.12) to an activatable proportional pilot valve (6), such that the separately activatable directional control valves (3.5, 3.6) can thus be activated by means of said pressure, which is built up by the pilot valve (6).

Abstract: A hydraulic control system for a machine is disclosed. The hydraulic control system may have a pump configured to pressurize fluid, a displacement control valve configured to affect displacement of the pump, and a tool control valve configured to receive pressurized fluid from the pump and to selectively direct to the pressurized fluid to a hydraulic actuator. The hydraulic control system may also have a controller in communication with the displacement control valve. The controller may be configured to determine a pressure gradient across the tool control valve substantially different than a desired pressure gradient, to determine a desired condition of the displacement control valve based the pressure gradient, and to determine a flow force applied to the displacement control valve based on the desired condition. The controller may be further configured to generate a load sense response signal directed to the displacement control valve based on the desired condition and the flow force.

Abstract: A hydraulic actuator for a hydraulic servomotor 4 is disclosed. The hydraulic servomotor 4 has a first chamber 5 and a second chamber 6 associated therewith. The hydraulic actuator is connected to a fluid source 2 and a fluid drain 3, and it comprises a valve assembly arranged between the fluid source 2 and the fluid drain 3 to control fluid pressures in the chambers 5, 6. At least one auxiliary valve 11 is fluidly connected between the valve assembly and the fluid drain 3, said auxiliary valve(s) 11 being of a kind which is normally closed in a de-energized state. In the case of a power cut off the auxiliary valve(s) 11 will close, thereby preventing fluid flow from the valve assembly towards the fluid drain 3. This causes a servomotor piston member 12 to be hydraulically locked in its instantaneous position, thereby locking the hydraulic servomotor 4. The valve assembly may be designed without taking the locking function into consideration.

Abstract: A hydraulic system for a leveling apparatus in excavator and forestry equipment is provided, whereby an upper frame of the equipment is kept in a horizontal state even if a lower frame of the equipment is on an inclined ground against a horizontal surface H. The hydraulic system a pair of first and second actuators and a pair of third and fourth actuators for rocking the lower part of the upper frame, first leveling control valves for simultaneously controlling extension and contraction of the first and second actuators, second leveling control valves for simultaneously controlling extension and contraction of the third and fourth actuators a reducing valve for discharging a reducing pilot signal pressure, and flow control valves for discharging the pilot signal pressure for the spool shifting of the first and second leveling control valves when a control signal is applied from a preset leveling controller.

Abstract: There is provided a hydraulic controller for a working machine in which a pilot hydraulic pressure source is connected in common to a plurality of pilot-operated hydraulic devices each having a pilot pressure input unit, and a common pilot pressure input switching valve is adapted to control the switching between a pilot pressure input from the pilot hydraulic pressure source to each pilot pressure input unit and a relief of the input. The switching control of a pilot pressure input by the pilot pressure input switching valve is performed based on the operating state of the working machine and pilot pressure input conditions of the respective pilot-operated hydraulic devices.

Abstract: A hydraulic circuit structure of a work vehicle capable of solving a problem in a conventional structure wherein, in a machine attitude control in back hoe operation, pressure oil is preferentially fed to light-loaded machines and some work machines are slowly moved or stopped and, accordingly, the attitudes of the machines cannot be rapidly controlled and work performance is affected. To solve this problem, the hydraulic circuit of the work vehicle comprises two valve groups for loader and back hoe having circuits to supply the pressure oil from one hydraulic pump P1 to a valve group 150 for back hoe control through a valve group 130 for loader control and the pressure oil from the other hydraulic pump P2 directly to the valve group 150 for back hoe control. The pressure oil is independently supplied from the hydraulic pumps P1 and P2 to valve sections 152 for controlling right and left stabilizer cylinders installed in the valve group 150 for back hoe control.

Abstract: Improvements in trunnion shaft-controlled swashplate axial hydraulic piston pumps as well as hydraulic systems used in hydrostatic transmissions utilized. e.g., in zero-turn-radius (ZTR) wheeled vehicles, such as grass mowers, with one embodiment thereof pertaining to, in combination, the noted pump, devoid of any internal servo control, and a reversible power actuator, for controlling the angle of the swashplate, externally affixed to the housing containing the pump and operatively interconnected with an end of the trunnion shaft extending from the pump housing, with the power actuator being one of a rotary actuator, a fluid power axial cylinder and a rotary electronic actuator.

Abstract: There is provided a hydraulic pump unit of variable displacement type disposed away from a pair of hydraulic motor units which are capable of being independently arranged, the pump unit fluidly-connected to the pair of hydraulic motor units so as to change the outputs of the pair of hydraulic motor units in both forward and reverse rotation directions. The pump unit includes a hydraulic pump body operatively rotated and driven by a driving source, a pump case surrounding the hydraulic pump body, a capacity adjusting mechanism for changing the capacity of the hydraulic pump body, and a hydraulic servomechanism for transmitting an external input based on a manual operation to the capacity adjusting mechanism by utilizing a hydraulic force.

Abstract: According to the present invention, an improved hydraulic transmission system is provided which includes a fluid supply adapted to supply hydraulic working fluid and having a hydraulic adjustment device for adjusting the flow rate of the hydraulic working fluid. A hydraulic control has an actuated condition in which the hydraulic control generates a hydraulic control fluid having a control pressure, which is adjustable between first and second control pressures. A first connection control operable by the hydraulic control fluid supplied from the hydraulic control is adapted to direct, upon actuation of the hydraulic control, the hydraulic control fluid to the hydraulic adjustment device. The first connection control includes a distributor having a control position in which it directs the hydraulic fluid to the adjustment device and a neutral position in which it connects the adjustment device to a tank.

Abstract: The invention relates to a connection block for a hydrostatic piston machine which is provided for simultaneous operation in a first hydraulic circuit and a second hydraulic circuit. A first working pressure duct (60) and a second working pressure duct (61) are formed in the connection block, via which ducts respectively a first and a second working line (7, 8) of the first hydraulic circuit can be connected to respectively a first and a second kidney-shaped control port of a control plate (52) of the hydrostatic piston machine. Furthermore, a third working pressure duct (62) and a fourth working pressure duct (63) are formed in the connection block (25), via which ducts respectively a third and a fourth working line (7?, 8?) of the second hydraulic circuit can be connected to respectively a third and a fourth kidney-shaped control port (70?, 71?) of the control plate of the hydrostatic piston machine.

Abstract: An axle driving apparatus comprising a common housing in which a hydraulic pump and a hydraulic motor fluidly connected with each other and an axle driven by the hydraulic motor are disposed, At least one of the hydraulic pump and the hydraulic motor is variable in displacement and has a capacity changing device for changing its capacity. A hydraulic actuator is provided in the housing for controlling the capacity changing device. A control valve for hydraulically controlling the hydraulic actuator is provided in the housing. A center section for fluidly connecting the hydraulic pump and the hydraulic motor with each other is fixedly disposed in the housing and a driving part of the hydraulic actuator and the control valve are incorporated in the center section. A rotary member operatively connected to a human-operated traveling control member provided on a vehicle is rotatably supported by the housing.

Abstract: A fluid pump control device for wheel loaders includes an engine for driving an axle through a transmission, a main pump, a variable-displacement steering pump with a pump regulator, an auxiliary pump, an electronic proportional control valve provided on a discharge quantity control signal line leading to the pump regulator for variably controlling a pilot pressure conveyed the pump regulator, a hydraulic load detector for detecting a real hydraulic load (Px), an engine revolution detector for detecting the number of revolution (N1) of the engine, a transmission revolution detector for detecting the number of output shaft revolution (N2) of the transmission. A controller is adapted to control the electronic proportional control valve and hence the fluid discharge quantity of the steering pump, based on the real hydraulic load (Px), the number of revolution (N1) of the engine and the number of output shaft revolution (N2) of the transmission.

Abstract: An axle driving apparatus comprising a common housing in which a hydraulic pump and a hydraulic motor fluidly connected with each other and an axle driven by the hydraulic motor are disposed, At least one of the hydraulic pump and the hydraulic motor is variable in displacement and has a capacity changing device for changing its capacity. A hydraulic actuator is provided in the housing for controlling the capacity changing device. A control valve for hydraulically controlling the hydraulic actuator is provided in the housing. A center section for fluidly connecting the hydraulic pump and the hydraulic motor with each other is fixedly disposed in the housing and a driving part of the hydraulic actuator and the control valve are incorporated in the center section. A rotary member operatively connected to a human-operated traveling control member provided on a vehicle is rotatably supported by the housing.

Abstract: An adjusting device (1) for adjusting the swash plate (12) of an axial piston engine (1) with a swash-plate construction has an actuating piston (18) which acts on the swash plate (12) of the axial piston engine (1); and a control value (19). The control valve (19) is used to regulate the actuating pressure which is present in an actuating volume (45) and which is acting on the actuating piston (18), in accordance with a control force acting on a valve piston (20) of the control valve (19). The actuating piston (18) is structurally separate from the control valve (19) and the actuating piston (18) is connected to the valve piston (20) of the control valve (19) by a readjusting spring (34) that opposes the control force.

Abstract: An axle driving apparatus comprising a common housing in which a hydraulic pump and a hydraulic motor fluidly connected with each other and an axle driven by the hydraulic motor are disposed, At least one of the hydraulic pump and the hydraulic motor is variable in displacement and has a capacity changing device for changing its capacity. A hydraulic actuator is provided in the housing for controlling the capacity changing device. A control valve for hydraulically controlling the hydraulic actuator is provided in the housing. A center section for fluidly connecting the hydraulic pump and the hydraulic motor with each other is fixedly disposed in the housing and a driving part of the hydraulic actuator and the control valve are incorporated in the center section. A rotary member operatively connected to a human-operated traveling control member provided on a vehicle is rotatably supported by the housing.

Abstract: A pump unit having a pump cylinder block mounted in a housing on an end cap. The cylinder block is driven by a pump input shaft, where the input shaft has a first driven end and a second end, and the second end extends through the end cap and out of the housing.

Abstract: In a configuration comprising a hydraulic servo mechanism (6) having a spool (72) as a hydraulic valve for controlling the swash plate angle disposed within a body housing (3) of a hydraulic continuously variable transmission (1 or 2), and a manual operation member (20) for operating the hydraulic servo mechanism disposed outside of the body housing, a casing (33) is provided between the manual operation member and the body housing, a neutral position holding mechanism (11) for holding the neutral position of a movable swash plate and a rotation control mechanism (34) for controlling the maximum rotating angle of the movable swash plate are installed in the casing, and further an over-stroke absorbing mechanism (27, 40) for absorbing the over-stroke of the manual operation member is installed in an area ranging from the inside of the casing to the inside of the body housing, and moreover a spool operating member (41) moving by operation of the manual operation member is disposed movably almost integrally with

Abstract: A fluid-pressure transmitting apparatus that is capable of securing the operationality of a working machine and braking and preventing against engine stall. The apparatus can switch between a working-machine operating device and a traveling operating device. When a second operating unit is operated during operation of a first operating unit, the pilot pressurized oil outputted from each operating means through first and second pilot-pressure admission passages is admitted to a low-pressure selecting valve. At this time, the pilot pressurized oil is automatically selected through the low-pressure selecting valve to control the delivery capacity of the traveling pump and braking and preventing engine stall and realizing travel at low speed.

Abstract: An axle driving apparatus comprising a common housing in which a hydraulic pump and a hydraulic motor fluidly connected with each other and an axle driven by the hydraulic motor are disposed. At least one of the hydraulic pump and the hydraulic motor is variable in displacement and has a capacity changing device for changing its capacity. A hydraulic actuator is provided in the housing for controlling the capacity changing device. A control valve for hydraulically controlling the hydraulic actuator is provided in the housing. A center section for fluidly connecting the hydraulic pump and the hydraulic motor with each other is fixedly disposed in the housing and a driving part of the hydraulic actuator and the control valve are incorporated in the center section. A rotary member operatively connected to a human-operated traveling control member provided on a vehicle is rotatably supported by the housing.

Abstract: The neutral override circuit of this invention includes a variable displacement pump controlled by a servo fluidly connected to a displacement control that is biased to a neutral position. A charge pump is connected to the pump and the displacement control. A solenoid-operated neutral override brake control valve is connected to the charge circuit upstream of the displacement control valve and is normally biased to an open position. However, the solenoid urges the valve to a closed position in a response to a signal indicating that the brake has been released. In the open position, the valve dumps charge flow to the pump case until the supply pressure to the displacement control is inadequate to overcome the centering bias of the displacement control. The characteristics of the brake control valve can be set so that some minimum charge pressure and lubricating flow are still provided to the rotating elements of the pump.

Abstract: A hydraulic system is provided for a vehicle having front, middle and rear portions. The hydraulic system includes a main pump located in the front portion, and a secondary pump located in the front portion which supplies fluid to an inlet of the main pump and to lube circuits. High pressure hydraulic functions are located in the middle and rear portions and receive high pressure fluid from the main pump. A hydraulic filter is located in the front portion and is connected to an outlet of the secondary pump for filtering fluid communicated to the inlet of the main pump. A relief valve is located in the front vehicle portion and is connected between the outlet of the secondary pump and the hydraulic filter. An inlet suction screen is located in the rear portion and is connected between a sump and the inlet of the main pump. An oil cooler is located in the front vehicle portion and is connected between the hydraulic filter and an inlet of the main pump.