Abstract: A fluid valve transmission having an automatic by-pass in neutral on the pump side and automatic brake or by-pass on the driven motor side while in the neutral position. Through holes and channels in the rotor are designed with close openings to open and close smoothly as the valve is turned, one opening as the other closes. All channels in the rotor are full of fluid at all times. The valve positions are designed with neutral midway between forward and reverse. This allows for quick start and stop and forward or reverse changes. Pressure equalization lines in the valve body from the pump and motor lines enter a circumferential channel on the rotor valve. This prevents the rotor from binding in high pressure applications.

Abstract: A hydrostatic transmission having a hydraulic pump and motor for use in a vehicle, including a center section for mounting and operatively connecting the pump and motor, a rotatable output drive shaft engaged to the hydraulic motor, and a running surface and support members integrally formed with the center section to fully support the output drive shaft, and further including a thrust bearing mounted in a housing for the transmission to engage said hydraulic motor, where the thrust bearing is supported by the upper and lower casing sections of the housing.

Abstract: The present invention relates to a control apparatus for a construction machine such as a hydraulic shovel, and the control apparatus for a construction machine includes a revolving operation member for operating a construction machine revolving unit (14), a fluid pressure pump (2) and an accumulator (5) for accumulating working oil from the fluid pressure pump (2), a fluid pressure actuator (7) for driving the construction machine revolving unit (14) to revolve with the working oil from the fluid pressure pump (2) and the accumulator (5), a first control valve (8) interposed between the fluid pressure actuator (7) and the fluid pressure pump (2), a second control valve (11) for controlling an inflow condition of the fluid from the fluid pressure actuator (7) into the accumulator (5), and control means (9) including first valve control means (9a) for controlling the first control valve (8) and second valve control means (9b) for controlling the second control valve (11).

Abstract: A hydraulic system for driving an axial piston type hydraulic motor wherein a swash plate can tilt at a right angle relative to a shaft.

Abstract: A neutral by-pass for hydraulic fluid in a hydrostatic transmission is provided by an essentially closed conduit comprising a pair of bores and a channel communicating the pair of bores, all formed in the cam ring of the transmission. When the neutral point is attained, the bores will be communicated with oil dampening pistons in communication with the hydraulic fluid supply passages and the fluid pressure between the passages will be equalized. This will operate from either the forward or reverse direction. As the cam ring is angularly moved, essentially closed conduit is moved away from the dampening pistons, so there can be no fluid flow therethrough. When this occurs, all fluid flow goes to the motor rotor, causing output rotation.

Abstract: An axle driving apparatus having a common housing of at least two separable pieces for a hydrostatic transmission comletely contained within the housing. A pair of oppositely-extending differentially-connected axles extend from the housing. The housing pieces are separable at a horizontal parting plane.

Abstract: A discharge flow control system and method of a hydraulic pump driven by an engine for the minimization of the difference between a discharge mount of flow in the pump and total mount of operating oil necessary to operate each actuator in hydraulic equipment. The control system is provided with a detector which detects the number of rotation of the engine, generates equal number of pulses to the number of rotation, a detector which detects the tilt angle of a swash plate of the pump, a detector which detects the operating displacement of the actuator, a detector which detects the load pressure acting on the pump, and a controll unit which controls a target discharge flow mount of the pump which is suitable for performing a predetermined work based on the number of rotation, the tilt angle, the displacement and the load pressure.

Abstract: An axle driving apparatus wherein a hydraulic motor and a hydraulic pump for a hydro-static-transmission are housed in a transmission casing of the axle driving apparatus and a center section for connecting the hydraulic motor and hydraulic pump is disposed in the transmission casing, the center section being fixed at the butt joint portion at the transmission casing, and an oil passage from the hydraulic pump to the hydraulic motor at the center section is bent at a right angle so as to extend the motor shaft in parallel to the axles, so that the rotation direction of the motor shaft conventionally changed by bevel gears is changed by the oil passages in the center section.

Abstract: A continuously variable hydrostatic transmission includes axially aligned input and output shafts journaled by a transmission housing and respectively coupled to a prime mover and a load. The input shaft drives a hydraulic pump unit, while a hydraulic motor unit is grounded to the transmission housing. A wedge-shaped swashplate is pivotally connected to the output shaft in operative position to accommodate pressurized hydraulic fluid exchanges between the pump and motor units. A controller is coupled to adjust the angular orientation of the swashplate relative to the output shaft axis and thus set the transmission ratio. A hydraulic circuit, connected into the hydraulic motor unit, is selectively operable to vent high and low fluid pressure sides of the swashplate to atmosphere, thus imposing a neutral transmission ratio condition regardless of the transmission ratio set by the controller.

Abstract: The present invention provides a swash plate type hydraulic actuator comprising cylinders provided with an inner oil passage, an outer oil passage, cylinder bores, radial valve holes extending between the inner oil passage and the outer oil passages, and ports opening into the cylinder bores and the valve holes, respectively. Distributing valves are slidably fitted in the valve holes for connecting the ports alternately to the inner oil passage and the outer oil passage. Swash plate holders, swash plates and eccentric rings supported on the swash plate holders so as to be engaged with the outer ends of the distributing valves respectively, are provided. Plungers are slidably fitted in the cylinder bores, respectively, in which the displacement can be changed whether or not the inclination of the swash plates is variable.

Abstract: A powered hose reel is described including a mounting base with a hydraulic motor mounted thereon. The motor is secured to a motor base that, in turn, is releasably secured to the mounting base. The motor further includes a driven rotatable live axle that directly mounts to a hose spool, providing direct driving forces to the spool. The spool includes a drum for receiving a hose, a central spacer disk mounted to the drum, and a center hub. The center hub is fitted to the live axle for coaxial rotation with the live axle such that the spool rotates in direct response to rotation of the motor live axle. A swivel is provided for connection to the inward hose end to allow winding and unwinding of the hose on the spool. Fairleads are provided on the base for guiding hose onto and off from the spool. A control valve may also be provided to selectively lock the motor, allow the motor to freewheel, or to operate to rewind the hose.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: A hydraulic nonstep transmission apparatus with low costs and high reliability is provided which is capable of automatically determining a speed-change ratio corresponding to engine speed and motor load and capable of smoothly performing clutch operation to a clutch-on state through a clutch meeting state. The apparatus comprises: a clutch means provided in a hydraulic closed circuit; a governor hydraulic actuator for moving the motor swash plate toward its vertical position in accordance with an increase in the rotational speed of an engine; and a governor hydraulic pressure switch means provided in a governor hydraulic fluid passage of the governor hydraulic actuator and drivingly connected to the clutch means to disconnect the governor hydraulic pressure during the period from a clutch-off state to the elapse of the clutch meeting state and to supply the governor hydraulic pressure before and after the transition to clutch-on after substantially completing the clutch meeting state.

Abstract: A ball and piston valve for controlling the flow of hydraulic fluid to a motive means have the ball and piston spring biased in opposing directions and with both initially subject to a first hydraulic fluid pressure that allows the springs to cause the ball to be unseated from its seat whereby fluid is directed to a fluid tank and wherein the ball is of sufficiently larger diameter than the piston that upon an increase in fluid pressure the ball is seated and remains seated when the pressure drops to the first hydraulic fluid pressure whereby the motive means to which the fluid is directed when the ball is seated does not have a sudden lurch upon a subsequent increase in pressure.

Abstract: A fluid pressure driving system for a vehicle includes a reservoir tank in which an amount of fluid is stored, a variable capacity oil pump sucking the fluid from the reservoir tank and discharging the resultant fluid, a control device for adjusting a quantity of the fluid discharged from the variable oil pump, and a distributor valve having an inlet port for receiving the fluid from the variable capacity oil pump. The distributor valve discharges a fixed amount of the fluid and the remaining amount of the fluid from a first outlet port thereof and a second outlet port thereof, respectively. A first passage connects the first outlet port of the distributor valve and the reservoir tank. A second passage connects the second outlet port of the distributor valve and the reservoir tank. A power steering device is associated with a steering wheel and disposed in the first passage. A hydraulic motor is disposed in the second passage, and a cooling fan is mounted rotatably on the hydraulic motor.

Abstract: A hydrostatic transaxle having a hydrostatic transmission includes a plate-like dump valve disposed between the transaxle housing or in a recess formed therein, adjacent a fluid conduit that connects the pump and motor of the transmission, the dump valve having fingers which unseat valves in the conduit to relief pressure therein. A rod having an offset portion extends through a bore in the dump valve, the rotation of the rod and offset portion urges the fingers of the plate-like dump valve towards or away from the conduit valves. The settling chamber disposed within the transmission includes protrusions upwardly projecting from the bottom of the chamber which trap particulates suspended in the hydraulic fluid that circulate through the system. A magnet is likewise disposed in the settling chamber adjacent the protrusions for attracting and holding magnetic particles and debris circulated by the hydraulic fluid.

Abstract: A clutch valve is constituted with a valve cylinder fitted in and fixed to the center of a cylinder block in a manner to form with the cylinder a third ring-shaped oil passage and a second ring-shaped oil passage to communicate with a first ring-shaped oil passage and a valve body slidably fitted in the valve cylinder in a switchable manner to communicate between the third and second ring-shaped oil passages and/or shut them off from each other.

Abstract: A hydraulically operated continuously variable transmission associated with the engine of a motor vehicle has a clutch for controlling the transfer of power through the transmission and a hydraulic servo unit for selectively connecting and disconnecting the clutch.

Abstract: A variable flowrate and variable pressure oil operated hydraulic rotary pump turbine, having radial blades, comprised of an oil tight casing (1) full of fluid, holding therewithin a rotor (2) provided with slots wherein blades (3) are slidably mounted. The blades having pivot pins and rings are guided in their motion by positive cams (7) machined in the casing cover. In the portion where the blades project the most out of the rotor, a sector (4) having semicylindrical cavity and whose motion is controlled by a camshaft (6) changes its distance relative to the blades whereby, in the pumping action, the fluid flowrate and pressure are modified. The camshaft is actuated by a lever with a centrifugal magnetic or electronic controller sensitive to the pump rotor RPM.

Abstract: A valve mechanism for a hydrostatic transmission having a variable displacement pump and a motor in fluid communication with each other via a closed-loop fluid system. The valve mechanism provides pressure relief and a wide neutral feature within a predetermined range of movement about a zero displacement or neutral position of the pump. The valve mechanism is variably controlled by and in coordination with the movement of the displacement pump control mechanism from a fully open position through a fully closed position, such that as the pump is shifted into and out of neutral from both a forward and reverse displacement position, the valve mechanism is moved therewith. The valve mechanism constitutes a ring surrounding the conduit and is responsive to the pump control mechanism so as to move concentrically therewith. The ring valve includes bores selectively communicating with respective bores in the fluid system such that the fluid system is in selective communication with a cavity formed in the housing.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: The invention refers to a hydraulic circuit for limiting the torque of a hydrostatic hydraulic motor connected in closed circuit to a hydraulic pump, which in braking mode operates as a hydraulic pump, in which pressure control valves are connected before and after the hydraulic motor. For the solution of this problem to develop such a hydraulic circuit which limits the maximum torque at the shaft of the hydraulic motor to approximately identical values independent of the fact whether the hydraulic motor is operated in the motor mode or in the pump mode, the pressure control valves consist of pilot-operated pressure control valves (6,7; 8,9). There is provided at least one on-off valve (5) which, when the hydraulic motor (2) is in the motor mode, switches the pilot-operated pressure control valve of the pressure side to a higher maximum pressure, and in pump mode it switches the pilot-operated pressure control valve of the other pressure side to a lower maximum pressure.

Abstract: An infinitely variable differential hydrostatic transmission utilizing a fixed displacement pump/motor and a variable displacement pump/motor interconnected with appropriate valving, to provide a mechanical/hydraulic differential drive which is capable of achieving an overall efficiency in the 98.degree.-99.degree. range. In the preferred embodiment, which utilizes axial piston type pump motors, pistons in multiples of four are utilized in order that each piston will have a piston located 90.degree. from it to serve as its control valve. The fixed and variable displacement motor/pump are provided as an integral unit containing bearing mountings, cylinder barrels, valve ports, piston seal mountings, hydraulic flow passages, pressure reservoirs and manifolding by forming a series of individual segments and sealing them together into a single structural unit. A unique mounting arrangement is utilized to positively attach the pistons to an anti-friction swashplate which eliminates all side loads on the piston.

Abstract: A hydraulic drive traveling system has a pressure compensated low control valve connected between a hydraulic pump and a variable displacement type hydraulic motor for controlling a flow rate of the hydraulic fluid supplied to the motor. The flow rate is controlled in accordance with the delivery pressure of the pump and demanded traveling speed of the motor. When the delivery pressure of the pump is at a high level, the motor is shifted to a first capacity. When the delivery pressure of the pump is low, the motor is shifted to either the second capacity or the first capacity depending upon the demanded traveling speed.

Abstract: An axle driving apparatus which houses in a transmission casing thereof a hydraulic motor and a hydraulic pump of a hydro-static-transmission and disposes in the transmission casing a center section for connecting the hydraulic motor and hydraulic pump, thereby fixing the center section at the butt joint of the casing and which disposes an oil filter and check valves or the like in the center section so that lubricating oil in the transmission casing is made absorbable as operating oil for the hydro-static-transmission.

Abstract: A hydrostatic transmission is provided of the type including a pump (15), a motor (17), and a pintle assembly (35) defining high (61) and low (63) pressure fluid conduits. In communication with the conduits, the pintle assembly includes a pair of acceleration valves (85, 89), each of which comprises a differential area piston. Adjacent each acceleration valve is a pilot valve means (95) disposed in a pilot bore (105) and including a valve member (115) operable, in response to system pressure in excess of the pressure relief setting of a spring (117) to relieve fluid pressure in a chamber (101), such that the acceleration valve (85) is biased toward an open position (FIG. 5) relieving fluid pressure spikes from the high pressure conduit (61) to the low pressure conduit (63).

Abstract: In an apparatus for controlling the operation of hydraulic motors having infinitely adjustable eccentricity, wherein a flow-control valve between a pump and a hydraulic motor supplied with pressure medium and a control valve for adjusting the eccentricity of the hydraulic motor as a function of the operating pressure required by the hydraulic motor are provided, in connection with pressure optimization for keeping constant the torque of the hydraulic motor, the hydraulic motor is provided with a regulating device (7,10) which is mechanically connected to the eccentric (3) and transmits an eccentric adjustment outward, wherein this mechanical regulating device (7,10) acts on the flow-control valve (17) in such a way that, as a function of the change in the eccentricity, the flow-control valve (17) controls the pressure-medium quantity supplied to the hydraulic motor in such a way that the speed of the hydraulic motor is kept constant.

Abstract: A hydrostatic transmission system axle driving apparatus for changing the speed of a vehicle which includes a hydraulic pump, hydraulic motor and braking unit. Neutral valves at an open position are automatically returned to a closed position with the operation of a brake controller. This allows the vehicle to be started at slow speed, but not abruptly.

Abstract: A power train for vehicles having a swashplate type continuously variable transmission having a swashplate hydraulic pump and a swashplate hydraulic motor, a transmission cylinder therebetween with a plurality of pump plunger holes and motor plunger holes formed therein. The transmission cylinder is rotatable about an axis and is coupled with the crankshaft of the engine. The pump swashplate is rotatable and disposed at an angle to the axis of the transmission cylinder and is coupled with pump plungers. A motor swashplate which is variably inclined relative to the axis of the cylinder and includes motor plungers associated with the cylinder.

Abstract: A variable-stroke crank mechanism includes a crankshaft rotatably mounted in a casing and having an eccentric crankpin, and a plurality of fluid pressure actuators disposed substantially radially with respect to the crankshaft, for pressing the eccentric crankpin to rotate the main shaft and the casing relatively to each other. The fluid pressure actuators are selectively supplied with a working fluid. An eccentric collar is rotatably mounted on the crankpin and operatively coupled to the fluid pressure actuators. The eccentric collar having an axis which is eccentrically displaced with respect to the axis of the crankpin. The crankpin and the eccentric collar are arrested in their respective angular positions by intermeshing internal and external gears. The crank mechanism may be incorporated in a plunger-type hydraulic unit, which may also be incorporated in a hydromechanical continuously variable transmission.

Abstract: A hydrostatic drive system consists respectively of an adjustable primary and secondary unit which are connected together via a conduit train with impressed pressure. The volume flow of the primary unit is regulated in dependence upon the impressed pressure and the volume flow of the secondary unit as a function of the speed. To avoid pronounced dropping of the impressed pressure the power of the secondary unit is limited. For this purpose a circuit is provided in which the volume flows of the primary and secondary units are compared. The power limitation intervenes when the volume flow of the secondary unit exceeds the volume flow of the primary unit.

Abstract: A torque transmission apparatus has a hydraulic assembly with a variable speed control, and comprises first and second rotors at a power side of the transmission apparatus, the rotors being coaxially rotatable with respect to each other. The first rotor has a swash plate facing the second rotor. The second rotor has a plurality of cylindrical bores which have open ends facing the swash plate and other ends which are communicated with through bores arranged in communication with ports. Plunger members are provided for sliding in the cylindrical bores, the plunger members being guided by the swash plate. A control rotor and a stator are provided at a control side of the transmission apparatus. The stator has a swash plate, and the control rotor has cylindrical bores having open ends facing the swash plate of the stator and communicating with through bores in the stator. Plungers are provided which slide in the cylindrical bores of the control rotor, guided by the variable swash plate of the stator.

Abstract: In a hydrostatic continuously variable transmission in which a clutch valve capable of operating between a clutch-on position for setting a hydraulic closed circuit between a hydraulic pump and a hydraulic motor to a hydraulic transmitting state and a clutch-off position for setting the hydraulic closed circuit to a hydraulic transmission cutting-off state is connected to the hydraulic closed circuit, a pressure bearing chamber for urging the clutch valve to the clutch-off position, and a pressure regulating spring for urging the valve to the clutch-on position are provided in the clutch valve, and a clutch controller for regulating the set load of the pressure regulating spring is connected to the pressure regulating spring. Thus, the degree of the hydraulic transmission between the pump and the motor can be controlled as desired without influence of the viscous change of a working oil. The clutch valve is disposed at one axial end of a transmission shaft.

Abstract: In a hydrostatic continuously variable transmission comprising an annular inner oil passage and an annular outer oil passage which are formed in the cylinder block between a large number of cylinder bores in the pump cylinder and a large number of cylinder bores in the motor cylinder so as to surround an axis of the cylinder block, large numbers of first and second distributor valves disposed radiately in the cylinder block and adapted to be reciprocally moved radially of the cylinder block, and a first and a second eccentric ring engaged with the first and second distributor valves, respectively, a large number of clutch valves are arranged radiately and circumferentially alternatively with the second distributor valves in the cylinder block and adapted to be reciprocally moved between radially inner and outer positions in the cylinder block to short-circuit the oil passages when the reciprocation stroke thereof exceeds a given value.

Abstract: A hydrostatically operated continuously variable transmission for use with an engine includes a swash-plate-type axial-piston hydraulic pump and a swash-plate-type axial-piston hydraulic motor which are interconnected by a closed hydraulic circuit. The pump and motor cylinders of the pump and the motor are disposed coaxially with each other and integrally coupled to each other into a cylinder block. An input shaft connected to an engine is coupled centrally to the cylinder block, and a output tubular shaft connected to a load is relatively rotatably disposed on an outer periphery of the cylinder block. The pump swash plate of the pump is supported by a stationary machine frame. The motor swash plate of the motor is supported by the output tubular shaft.

Abstract: When a first rotating shaft is rotationally driven, it rotates a first cylinder barrel splined thereto, and a second cylinder barrel and a valve block united with the first cylinder barrel. In accordance with these rotations, first pistons in first cylinders slide circumferentially on the inclined face of a first swash plate so that they are reciprocated axially in the first cylinder barrel, and second pistons in second cylinders slide circumferentially on the inclined face of a second swash plate so that they are reciprocated axially in the second cylinder barrel. Simultaneously with these reciprocations, a first change-over valve is switched in accordance with the rotations of the first rotating shaft, and a second change-over valve is switched in accordance with the relative rotations of the first rotating shaft and the second rotating shaft.

Abstract: In a hydrostatic transmission comprising a pump and a hydraulic motor arranged in a main line having low pressure and high pressure sections, wherein an oil drain line of the hydraulic motor is connected to the low pressure section of the main line, the housing of the hydraulic motor is freed from excessively high pressures in the main line by arranging a valve having an adjustable passage cross-section which decreases with increasing pressure in the main line before--in the direction of flow--the line connection of the oil drain line.

Abstract: A hydrostatic driving gear is described comprising a primary unit rotationally driven by a driving engine and a secondary unit rotationally driving an actuator. Each unit comprises a variable displacement hydraulic engine, in particular an axial piston engine. They cooperate in an open circuit. The primary unit and secondary unit each have a displacement adjusting device and can be continuously adjusted in respect of their direction of displacement through a zero displacement center position in two directions of displacement. The displacement adjusting device of the primary unit has associated with it a pressure flow controller which holds the working pressure at a constant presettable value. The displacement adjusting device of the secondary unit has associated with it a speed of rotation detecting device, having a position sensor to detect the flow setting.

Abstract: The present invention is a neutral shifting mechanism for a hydrostatic transmission. A motor track ring has a groove and cam slot for receiving a control rod of the transmission, with the control rod having a cam portion for engaging the cam slot to lock the track ring in a position concentric with the pintle of the hydraulic motor, i.e. a neutral position. In the normal position, the cam portion positions the track ring eccentrically, allowing a speed control shaft to shift the hydrostatic transmission by pivoting the pump track ring about the control rod.

Abstract: A hydromechanical drive wherein a prime mover drives an input shaft which, in turn, can drive a coaxial output shaft by way of a clutch or transmission having one or more axial piston pumps. The pressure and/or rate of fluid flow in the pump or pumps is adjustable by one or more valves or by one or more tiltable wobble plates in response to signals from one or more adjusting devices which receive signals from an electronic control circuit. The latter further receives signals from tachometer generators which monitor the RPM of the input and output shafts, from a gauge which monitors the pressure in the pump or pumps, from the valve or valves, or from the adjusting devices(s) for the tiltable wobble plate(s).

Abstract: A hydrostatic transmission having a housing with a sump and a pair of hydraulic displacement units interconnected by first and second fluid passages. A pair of bypass valves can be opened to place said first and second fluid passages in fluid communication. A recess, formed in the lower part of the housing, holds make-up oil and communicates with said first and second fluid passages when the bypass valves are opened. A passage extends upwardly from the housing recess and has its upper end normally sealed by seal means. A manually operable bypass rod extends lengthwise of the passage into the area of the housing recess and has structure associated therewith for causing opening of the bypass valves.

Abstract: An infinitely variable high efficiency drive mechanism that can act as a transmission or as a coupling between a prime mover and the reducing gears of a standard or automatic transmission, replacing a clutch or torque converter as a means of power transmission. This mechanism includes a hydraulic pump with a self-contained valve that keeps high pressure oil flow to a minimal distance. It can regulate shaft output torque ratio from zero (neutral) to 1:1 in locked position with minimal efficiency losses.

Abstract: A hydrostatically operated continuously variable transmission includes a cylinder block centrally coupled to a transmission shaft coupled to an engine, a swash-plate-type axial-piston hydraulic pump having a group of pump plungers, a hydraulic motor having a group of motor plungers, and a closed hydraulic circuit by which the hydraulic pump and the hydraulic motor are interconnected. The groups of pump and motor plungers are disposed in annular patterns in the cylinder block, and disposed concentrically such that one of the groups surrounds the other group. The plunger groups are positionally displaced in the circumferential direction of the cylinder block such that a circle inscribed in said one group passes through the other group.

Abstract: A hydraulically operated continuously variable transmission comprising a hydraulic motor of the variable displacement type having a motor cylinder coupled to an output shaft and including motor plungers slidably disposed respectively in a number of cylinder holes defined in an annular pattern surrounding the axis of rotation of the motor cylinder, and a hydraulic pump coupled to an input shaft. The hydraulic motor and hydraulic pump are interconnected by a closed hydraulic circuit in which the flow of working oil is controlled by a distribution ring which is relatively rotatably and slidably held against an end surface of the motor cylinder for successively switching the introduction of working oil into the cylinder bores and the discharge of working oil from the cylinder bores in response to rotation of the motor cylinder. The distribution ring has an asymmetrical hydraulic pressure bearing area in order to minimize forces tending to tilt the distribution ring relative to the motor cylinder end surface.

Abstract: A hydrostatic continuously variable transmission comprising a hydraulic pump having a pump cylinder, a hydraulic motor having a motor cylinder and a hydraulic closed circuit between the pump and motor, wherein the pump cylinder and motor cylinder are connected integrally rotatably to form a transmission member, one of input and output sections of the transmission being formed on the outer periphery of one of the cylinders and the other of the sections being formed by a transmission shaft which relatively rotatably carries the cylinders. The hydraulic closed circuit includes groups of first and second distributor valves for controlling transfer of working oil between the pump and motor through oil passages and first and second valve driving means for driving these groups of valves are arranged such that one is inside and the other is outside of a cylinder block formed of the pump and motor cylinders. This allows a transmission to have a compact size and a high industrial utility.

Abstract: The apparatus for the feed and control of the speed and torque of a hydraulic motor having variable swept volume according to this invention comprises a hydraulic feed device for the motor, adapted for supplying the required flow rate of hydraulic fluid under all conditions at the working pressure, a constant pressure hydraulic control circuit associated with the hydraulic device or devices for varying the swept volume fo the motor, adapted for modifying the swept volume itself in relation to the pressure of the hydraulic fluid supplied to the motor, and a flow regulator valve with proportional control, piloted by an electronic regulator generating a control signal for the valve and receiving the signal of a sensor of the rotational speed of the motor and a reference signal.

Abstract: In a hydrostatic continuously variable transmission, a pump cylinder of a swashplate type hydraulic pump is integrally and coaxially coupled with a motor cylinder of a swashplate type hydraulic motor. A number of distributor valves are radially arranged for reciprocal movement between radially inner and outer positions to put a large number of pump ports in the hydraulic pump into communication with the higher and lower pressure oil passages, and an eccentric ring circumscribed about the distributor valves is connected to an input member of the hydraulic pump for movement between a clutch OFF position and a clutch ON position. A clutch spring is connected to the eccentric ring for biasing the eccentric ring toward the clutch OFF position, and a weight is added to the eccentric ring and adapted to exhibit a centrifugal force for moving the eccentric ring toward the clutch ON position against a spring force of the clutch spring.

Abstract: A hydraulic continuously variable speed transmission comprises a hydraulic closed circuit for hydraulically connecting the hydraulic pump and the hydraulic motor, a direct clutch valve placed in the closed circuit to block it, a speed reduction ratio control actuator to control the speed reduction ratio, a direct clutch actuator for moving said direct clutch valve from a full-open position to a full-closed position, ratio detecting means which detects the speed reduction ratio and valve position detecting means which detects position of the direct clutch valve to find if the direct clutch valve is moved to a slight-open position. The direct clutch valve is moved quickly from the full-open position to the slight-open position when it is found by the ratio detecting means that the speed reduction ratio has become "1", and then the direct clutch valve is moved slowly from the slight-open position to the full-closed position when it is found that the direct clutch valve has been moved to the slight-open position.

Abstract: A continuously variable transmission employing a hydraulic motor and a hydraulic pump that are interconnected by a closed hydraulic circuit. An oil chamber is defined between the pump cylinder of the hydraulic pump and the motor cylinder of the hydraulic motor. A common oil cooling unit is connected through oil passages to the closed hydraulic circuit and the oil chamber for cooling heated oil supplied therefrom. The common oil cooling unit effectively cools the oil from the two sources since the heat developed in the oil from the two sources generally varies inversely during different modes of operation.