Abstract: A loop flushing circuit includes a loop flushing valve that is connected to the low pressure system line in a hydrostatic transmission for selectively bleeding fluid therefrom to the case drain without relying on a shuttle valve to identify the low pressure line. The loop flushing valve is adaptable to electrical or electro-hydraulic actuation by a microcontroller. Thus, the timing of loop flushing can be controlled based upon various system operating conditions or input values. Loop flushing with this circuit avoids adversely impacting control characteristics of the transmission, can be defeated around neutral, and can provide single-sided loop flushing.

Abstract: The present invention provides a pump unit including at least one hydraulic pump with inlet and outlet ports, a pump case for accommodating the hydraulic pump having an opening through which the hydraulic pump is insertable, and a lid, called a center section, closing the pump case. The center section forms a pair of inlet/outlet passages communicating an end with the inlet and outlet ports of the hydraulic pump and an end opening through a pump case abutting surface of the center section, and a first charging passage by which hydraulic fluid is fed through the pump case abutting surface of the center section. At least one of the pump case and the center section communicates the first charging passage with the pair of inlet/outlet passages via a first hydraulic fluid feeding valve preventing the reverse flow into said first charging passage.

Abstract: The tapping circuit forms part of a main fluid circuit which comprises a hydraulic motor having a preferred operating direction and at least two main pipes suitable for communicating with the cylinder block of the motor and constituting respectively, in said preferred operating direction, a feed main pipe and a discharge main pipe. The tapping circuit comprises a single tapping and removal valve connected continuously via a tapping pipe to that one of said main pipes which, in the preferred direction, serves for discharge purposes. This valve serves to replenish the fluid so as to cool it and/or to flush the internal space of the casing of the motor.

Abstract: A free piston engine system, particularly suitable for use in a motorized vehicle, is provided with at least one hydraulic pump, each pump having a first fluid port and a second fluid port. A free piston internal combustion engine includes a combustion cylinder and a hydraulic cylinder. A low pressure accumulator is fluidly coupled with the hydraulic cylinder. A first control valve interconnects the low pressure accumulator with the hydraulic cylinder. At least one high pressure accumulator is fluidly coupled with the hydraulic cylinder. At least one second control valve is provided, with each second control valve interconnecting a respective high pressure accumulator with the hydraulic cylinder. A third control valve interconnects the hydraulic cylinder with the first fluid port of each pump. A fourth control valve interconnects the hydraulic cylinder with the second fluid port of each pump. A first working pressure accumulator is coupled between each pump and the third control valve or fourth control valve.

Abstract: An hydraulic control system for an IDG includes in flow series arrangement a scavenge pump, a spool valve and a boost pump. When the spool valve detects an interruption in the supply pressure to the boost pump due to an adverse “g” condition, it reconfigures the system to a closed loop system. In this mode, the oil returning from the CVT is re-circulated back to the boost pump instead of back to the scavenge pump. A small accumulator of oil is used to make up for leakage in the system.

Abstract: A loop flushing arrangement for controlling a closed circuit hydraulic propulsion drive. The variable displacement pump 12 is driven by a combustion engine 11. A flush valve 21 is used to clean and cool the hydraulic fluid in the closed hydraulic circuit. The flush valve is electrically operated and, as a result, permits novel and varied control options. The flush valve is controlled automatically, for example by a digital computer 1 as a function of the vehicle speed, the rotational speed of the combustion engine 11, or the temperature of the hydraulic fluid in the variable displacement pump 12. This results in the flushing procedure only being triggered and carried out if the operating state of the vehicle requires and permits it, i.e. when traveling at high speeds, for example.

Abstract: A bypass mechanism is provided for use in a hydrostatic transmission, to enable the user to open or close a bypass between the hydraulic circuit of the transmission and a sump. The invention also comprises a safety mechanism to prevent excessive freewheeling of the vehicle by providing a plate or other bypass mechanism which engages a valve. The plate or other mechanism is moveable between a first position where the valve opens the hydraulic circuit to the sump and a second position where the valve closes the hydraulic circuit, and a spring mechanism enables the valve to override the bypass mechanism and force the circuit closed under excessive pressure.

Abstract: The invention provides a hydraulic circuit for construction machines, capable of obtaining a satisfactory suspending capability during load suspending work, and having an improved operation efficiency with a decrease in the working speed of a load suspending operation minimized, the hydraulic circuit including a suspension mode switch for setting a working mode to a suspension mode, a lift detecting sensor for detecting a predetermined actuator which has been operated to a load lifting side, a relief valve control unit capable of freely setting an object pressure of the relief valve 14 to a normal set level and a high set level higher than the normal set level, a cutoff valve control unit capable of freely switching the cutoff valve to a cutoff operation executing mode and a cutoff operation disengaging mode, and a controller adapted to increase a set pressure of the relief valve by outputting an instruction to the relief valve control unit when the controller receives a suspension mode signal and a lift dete

Abstract: The hydrostatic drive with regeneration circuit comprises a geroter flow divider which operates in conjunction with a two position three way valve and a check valve to provide regeneration flow for the hydrostatic drive when the valve is energized.

Abstract: A loop flushing circuit for a hydrostatic transmission module includes a three position, three port pilot pressure operated loop flushing valve having a first inlet port fluidly connected to the first system pressure line, a second inlet port fluidly connected to the second system pressure line and an outlet port fluidly connecting the loop flushing valve to the case drain through a drain line having a drain orifice therein. A loop flushing and lubrication line fluidly connected to the drain line upstream of the drain orifice extends within the casing and has an open end directed toward the rotating elements of one of the pump and motor. The three position valve has an intermediate position operatively located between the opposite end positions. System pressure from at least one of the first and second system pressure lines is always routed to the loop flushing and lubrication line through the valve regardless of which of the three positions the valve is in.

Abstract: A transaxle casing for a vehicle is adapted for various types of loading through the use of bearing holders. Power from an engine of the vehicle is transmitted to a differential in a transaxle casing. The transaxle casing has laterally outwardly extending left and right axle housing portions. Left and right driving axles are supported in the axle housing portions of the transaxle casing through bearings. Concavities are formed in each of the axle housing portions. When the transaxle casing is employed by a light vehicle or under a light load, needle bearings and seals are fitted in the concavities of the axle housing portions for journalling the ends of the left and right driving axles. When the transaxle casing is employed by a heavy vehicle or under a heavy load, the needle bearings and seals are removed and bearing holders containing ball bearings are attached to the ends of the axle housing portions by inserting convexities formed in the bearing holders into the concavities of the axle housing portions.

Abstract: An electromechanical bypass mechanism is provided for use in a hydrostatic transmission, to enable the user to open or close a bypass to the hydraulic circuit of the transmission through use of an switch mechanism attached to the bypass mechanism in the circuit. The invention also comprises an improved neutral feature for hydrostatic transmissions, with a switch connected to the control mechanism for the unit, whereby the switch is activated to place the unit in bypass when said mechanism is placed in the neutral location. A means is provided for opening and closing a shunt or bypass between the high pressure side and the low pressure side of the hydrostatic system which is triggered by an electrical signal.

Abstract: A relief pressure controlling device comprises a driving side relief pressure controlling valve, a capacity detector which detects the capacity of a hydraulic pump, and an engine throttle opening detector. When the hydraulic pump and the hydraulic motor which are connected by a first oil passage and a second oil passage constituting a hydraulic closed circuit are driven by an engine, the relief pressure controlling valve controls the relief pressure of the oil passage on the driving side that is either the first oil passage or the second oil passage whose pressure becomes higher than the other, to a target relief pressure. The target relief pressure is determined in correspondence with the engine output and corrected on the basis of the pump efficiency which is predetermined in relation to the capacity of the hydraulic pump and to the throttle opening, and this corrected target relief pressure is set as a driving side target relief pressure.

Abstract: A valve mechanism for use in a hydrostatic transmission including a closed porting system for hydraulic fluid and a sump is provided. The valve mechanism includes a valve body mounted to the hydrostatic transmission whereby the valve body is open to the closed porting system at one end thereof and open to the sump at the other end thereof. The valve body has a first open position whereby hydraulic fluid is pulled into the closed system from the sump when the pressure of the fluid in the closed system is below a first pressure, a second open position whereby hydraulic fluid exists the closed system to the sump when the pressure of the fluid is at a second pressure higher than the first pressure, and a closed position when the pressure of the hydraulic fluid in the closed system is at a third pressure higher than the second pressure.

Abstract: A hydrostatic-mechanical drive unit for a mixing drum, especially of a mobile concrete mixer has pistons (24) of a hydraulic motor (25) that are spring-loaded so as to constantly bear, via rollers (25), on a cam surface (26). With a hydraulic pump (2) stationary, the operating mode of the hydraulic motor (6) can be reversed. In order to reliably prevent further oscillation of the mixing drum, suction valves (32, 33) are connected to lines (4, 5) leading to the hydraulic motor (6) so that when the mode principle of the hydraulic motor (6) is reversed, oil can be inducted from an oil reservoir.

Abstract: A valve mechanism for use in a hydrostatic transmission including a closed porting system for hydraulic fluid and a sump is provided. The valve mechanism includes a valve body mounted to the hydrostatic transmission whereby the valve body is open to the closed porting system at one end thereof and open to the sump at the other end thereof. The valve body has a first open position whereby hydraulic fluid is pulled into the closed system from the sump when the pressure of the fluid in the closed system is below a first pressure, a second open position whereby hydraulic fluid exists the closed system to the sump when the pressure of the fluid is at a second pressure higher than the first pressure, and a closed position when the pressure of the hydraulic fluid in the closed system is at a third pressure higher than the second pressure.

Abstract: A hydrostatic transmission constructed so that a check valve and a relief valve are made as compact as possible to supply oil to a closed circuit for connecting a hydraulic pump and a hydraulic motor, and to regulate maximum pressure in the closed circuit. A check valve and a relief valve are contained in a valve casing. A valve body of the relief valve is disposed opposite to a valve body of the check valve. A relief spring of the relief valve is retained by a cover detachably mounted to an open end of the valve casing, thereby facilitating pressure setting of the relief valve. The valve body of the relief valve is contained in a relief valve casing slidably disposed in the valve casing. A plunger, capable of urging the check valve in the opening direction via the relief valve casing, is provided in the cover, thereby enabling the check valve to be manually opened.

Abstract: A hydraulic circuit for controlling a plurality of hydraulic motors of a machine has a reversible pump with its suction/pressure ports connected to the inputs of an OR-valve is connected to the input of at least one 3/2 electro-valve, which has its output connected to the inputs of the AND-valves which are not connected to the pump. The AND-valve outputs and the suction/pressure ports are used individually or in combination to control the hydraulic motors.

Abstract: A hydrostatic transmission. The hydrostatic transmission generally comprises a sump containing hydraulic fluid, a charge pump in flow communication with the sump for creating high pressure hydraulic fluid from the hydraulic fluid, a center section having hydraulic porting formed therein, a hydraulic pump, a hydraulic motor drivingly connected to the hydraulic pump through the hydraulic porting, and a manifold defining a gallery for storing the high pressure fluid. The gallery is in flow communication with the charge pump and the hydraulic porting.

Abstract: An axle driving apparatus in which a hydraulic pump and a hydraulic motor which constitute a hydrostatic transmission are disposed on a center section. In a horizontal portion of the center section are provided a pair of linear oil passages in parallel to each other. A pair of arcuate ports are provided on a pump mounting surface formed on the horizontal portion of the center section. The pair of arcuate ports are substantially perpendicular with respect to the direction in which the oil passages extend. The axis of slanting movement of a movable swash plate of the hydraulic pump extends laterally of the vehicle body on which the axle driving apparatus is provided. The rotating direction of an arm provided on a control shaft for slantingly operating the movable swash plate is coincident with the operating direction of a control rod connected with a speed changing member. Thus, the link mechanism for connecting the speed changing member and the control arm for the movable swash plate is simplified.

Abstract: An electrohydraulic control system that includes a bidirectional electric motor responsive to application of electrical power for rotation in either of two directions, and a hydraulic pump coupled to the motor and having ports for supplying hydraulic fluid in either of two flow directions as a function of direction of rotation of the electric motor. A hydraulic actuator is coupled to the pump for receiving fluid in either of two flow directions and performing work as a function thereof. An electronic controller applies electrical power to the electric motor so as to obtain a desired level of work at the actuator. The electronic controller includes one or more sensors operatively coupled to the actuator for applying electrical power to the motor as a function of motion at the actuator.

Abstract: The invention concerns a hydrostatic-mechanical gear for driving a mixed drum and, in particular, the drum of a concrete mixer vehicle. Cooling is provided for by the continuous removal of oil from a high pressure circuit, via a connecting pipe, and the constant feeding of the cooled oil, which has passed through an oil cooler, to the interior of a gear housing via a pipe. This pipe discharges into the interior of the gear housing immediately proximate a hydraulic motor. The oil then flows through the hydraulic motor, which is preferably a slow-speed radial piston motor, to reduce the noise generation of the hydraulic motor.

Abstract: Motor vehicle hydrostatic transmission having an internal oil expansion chamber including a main housing having at least one opening, this main housing including a sump pump oil reservoir having a predetermined volume of sump pump oil and an input cover sealingly attached to an opening in the main housing, this input cover having an internal oil expansion reservoir which captures or traps a specified volume of air above the sump pump oil level. Thus, when the oil level rises due to elevated operating temperatures, this captured or trapped air volume is decreased resulting in an increase in both the captured or trapped air pressure and the sump pump oil pressure. This causes an increase in the hydrostatic transmission's operating efficiency since the sump pump oil pressure acts as a charge pump to supercharge the low pressure inlet of the closed loop hydraulic system. In addition, the hydrostatic transmission bearing performance will increase since they are designed to operate under pressure.

Abstract: The invention relates to a fork-lift truck with a hydraulic drive comprising a hydraulic motor, a power source driving the hydraulic motor and a hydraulic control system driving the power source, characterized in that, the coupling of the hydraulic motor to the power source has arranged a sensor for measuring the pressure difference over the hydraulic motor, where the sensor is connected to a valve short-circuiting the hydraulic control system.

Abstract: The disclosure relates to a new valve and a hydraulic system incorporating such valve. A mode-selection assembly on the valve is adjustable between an open-loop position for system purging and a closed-loop position for normal system operation. A sealing member moves with the spool and with the mode-selection assembly in the open-loop position, the sealing member may be urged against a stationary abutment member in the valve. Such cooperative sealing member/abutment member contact blocks the closed-loop flow path and causes fluid to be "rerouted" to tank rather than back to the pump. The system is thereby temporarily converted to open-loop configuration for purging and is restored to closed-loop configuration by moving the mode-selection assembly to the closed-loop position. The new valve is particularly useful in hydraulic steering circuits for boats.

Abstract: An automotive air conditioning system is provided. The air conditioning system includes an air conditioning compressor. A reservoir having fluid is provided. A pump is interconnected with the reservoir and operatively interconnected with and driven by an engine of a vehicle. The pressure chamber is interconnected with the pump and receives fluid from the pump. A fluid drive element, located relative to the pressure chamber, and interconnected with the air conditioning compressor, converts a passage of pressurized fluid therethrough into mechanical driving force for driving the air conditioning compressor. A regulator maintains a selected level of pressure in the pressure chamber and diverts excess fluid from the pressure chamber to the reservoir so that a constant air conditioning compressor driving speed is maintained.

Abstract: A hydraulic circuit for supplying a plurality of series-operated consumers of a hydraulically controlled installation, in particular of an injection molding machine, having a pump with feed-flow pressure control, is described. To be able to slow down greater moving masses with very little expenditure in regard to circuitry and devices, only a portion of the consumers, such as the extruder, the injection unit and possibly the ejector are operated in open circulation, while at least one selected further consumer, such as the clamping unit of the injection molding machine, where a greater mass must be moved in alternating directions, is moved in semi-closed or closed circulation.

Abstract: A hydrostatic transmission constructed so that a check valve and a relief valve are made as compact as possible to supply oil to a closed circuit for connecting a hydraulic pump and a hydraulic motor, and to regulate maximum pressure in the closed circuit. A check valve and a relief valve are contained in a valve casing. A valve body of the relief valve is disposed opposite to a valve body of the check valve. A relief spring of the relief valve is retained by a cover detachably mounted to an open end of the valve casing, thereby facilitating pressure setting of the relief valve. The valve body of the relief valve is contained in a relief valve casing slidably disposed in the valve casing. A plunger, capable of urging the check valve in the opening direction via the relief valve casing, is provided in the cover, thereby enabling the check valve to be manually opened.

Abstract: A valve mechanism for use in a hydrostatic transmission including a closed porting system for hydraulic fluid and a sump is provided. The valve mechanism includes a valve body mounted to the hydrostatic transmission whereby the valve body is open to the closed porting system at one end thereof and open to the sump at the other end thereof. The valve body has a first open position whereby hydraulic fluid is pulled into the closed system from the sump when the pressure of the fluid in the closed system is below a first pressure, a second open position whereby hydraulic fluid exists the closed system to the sump when the pressure of the fluid is at a second pressure higher than the first pressure, and a closed position when the pressure of the hydraulic fluid in the closed system is at a third pressure higher than the second pressure.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

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 intergrated 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 therefor 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-motor drive circuit system includes an auxiliary hydraulic source connected to one end of an auxiliary line, a low-pressure selector connected to the other end of the auxiliary line and a pair of main lines for causing the other end of the auxiliary line to communicate with one of the main lines on the low pressure side during rotation of a hydraulic motor for driving an inertia load, and a switching control arranged in the auxiliary line for supplying the hydraulic fluid from the auxiliary hydraulic source to the other end of the auxiliary line when the directional control valve is in a neutral position, cutting off the hydraulic fluid from the auxiliary hydraulic source to the other end of the auxiliary line when the directional control valve is in an operative position.

Abstract: An hydraulic actuator composed of a double-acting actuator, a mobile switching member disposed in a housing connected hydraulically to the actuator, two fluid inlet and outlet pipes and a control member adapted to command the mobile switching member to move between a neutral configuration and an active service configuration. A variable speed pump system is connected to the housing by an auxiliary circuit; the mobile switching member has an active second configuration in which the actuator communicates with the auxiliary circuits, whereby the actuator, the pump system and the auxiliary circuit constitute a hydrostatic transmission.

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: Device for controlling the pressure in a hydraulic pressure system in which the output of a constantly running pump which feeds pressure medium to a pressure system is controlled by means of a suction throttle valve which itself is actuated as a function of the pressure in the pressure system of the vacuum in the connection between pump and suction throttle valve.An over pressure in the pump output acts to close the throttle valve, while under vacuum in the pump outlet acts to open the throttle valve, thus allowing for a two point control without additional control valves.

Abstract: The invention relates to a braking valve arrangement for a hydrostatic drive operated in open circuit, in particular for vehicle drives, wherein a hydraulic pressure medium is supplied to the hydraulic motor from the hydraulic pump via a reversing directional control valve as desired through one of two branches each containing a pressure limiting valve and a braking control valve, and the pressure medium is discharged to the tank through the respective other of the two branches. The braking control valve controls the flow of hydraulic medium through the respective branch depending on the pressure in the respective other branch and has parallel with it a non-return valve opening into the hydraulic motor.

Abstract: In a hydraulic drive, in which a double-acting working cylinder (10) is connected to the hydraulic power source by very long working lines (20, 22), it is proposed to connect a bypass line (36) containing a normally closed bypass valve (38) to the ends of the working lines (20, 22) nearest the cylinder. The bypass valve (38) is periodically opened to allow the fluid contained in the working lines (20, 22) to be completely replaced.

Abstract: A single hydraulic pump (6) is employed in a vehicle for supplementing fluid to a hydrostatic transmission (1) and for supplying fluid to a fluid-operated clutch (2) and to high pressure-actuated hydraulic actuators (3, 4, 5). Fluid discharge path (7) of the pump is connected to the hydrostatic transmission through a pressure-reducing valve (8). Fluid drain path (9) of the reducing valve is fashioned to a fluid supply path for the clutch. A second fluid supply path (11) is connected to the discharge path for supplying fluid to the hydraulic actuators and include a relief valve (12) or orifice (12A) for maintaining fluid pressure in the discharge path higher than the output pressure of the reducing valve. A high pressure relief valve (10) for establishing fluid pressure to be applied to the actuators is connected to the discharge path for minimizing a discharge pressure required to the pump.

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: A hydrostatic transmission pressure release valve control mechanism is provided to enable an operator to quickly release the transmission pressure and manually move the vehicle when the engine is not operating. The pressure release mechanism, which permits vehicle movement for repairs, maintenance and similar activities, is automatically deactivated to restore transmission pressure as the vehicle brake is depressed in preparation for restarting the engine.

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: In order that a hydraulic pump and a hydraulic motor of a hydrostatic transmission hitherto disposed to the exterior are attached to a hydrostatic transmission support member provided in a mission case, a charging pump hitherto attached to the hydraulic pump at the hydrostatic transmission is also attached to the hydrostatic transmission support member, and an oil filter hitherto attached to the outside of mission case is disposed therein, they are interposed between the lower surface of hydrostatic transmission support member and the charging pump. Furthermore, an outward takeout pump also is supported in the mission case.

Abstract: A control system for the hydraulic operating circuit associated with a vehicle lifting device in which the circuit is provided with pressure fluid control valves and flow sensors which are operative on the vehicle lowering cycle to establish substantial evenness of the lowering mechanism and protection against malfunction of an operating component to arrest the travel of the vehicle lifting device in its lowering cycle.

Abstract: An automatic speed changing apparatus, employable for a motorcar, which includes a hydraulic pump on the driving side mounted on a driving shaft, a plurality of hydraulic motors on the driven side mounted on a driven shaft, a distributor including a cylinder and a piston slidably received in the cylinder, a hydraulic oil collecting pipe having a large diameter in which working hydraulic oil is stored for the hydraulic pump and motors on both the driving and driven sides, an idling lever pivotally supported in the cylinder to be operable during a period of idling and a piston lever for displacing the piston axially in the cylinder during normal operation and during a period of engine braking.

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: A hydraulically operated tilt and trim system having an arrangement for permitting retraction of the trim cylinders when the outboard drive is in its tilted up out of the water condition. An arrangement for bleeding air from the system and for adding make up fluid to the system through the trim retraction circuit.

Abstract: An axle driving apparatus which houses in a transmission casing thereof a hydraulic motor and a hydraulic pump at 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: The present invention is an expander band for use in hydraulic pumps, motors, and hydrostatic transmissions. The band has a plurality of elongated slots located circumferentially which receive slippers attached to pistons. One reduced dimension slot fixes the position of a slipper relative to the expander band while the other slippers move within the elongated slots. The fixed slipper limits the range of movement of the other slippers relative to the band, and thus the slippers avoid abutting the side ends of the elongated slots.

Abstract: To inhibit potentially damaging cold startup of a hydrostatic unit in a vehicle transmission, a portion of the makeup fluid pump to the hydraulic pump and motor loop circuit of the hydrostatic unit is directed through a branch line including a viscosity insensitive, flow regulating fluidic element and a viscosity sensitive fluidic element. The latter element develops a fluidic signal varying as a function of fluid viscosity, which is utilized to control a valve to prevent over-pressurization of the loop circuit and to control a transmission controller to condition the transmission to neutral until the hydraulic fluid warms to a safe operating viscosity.