Abstract: A hydrostatic transaxle comprises: a housing, an interior space of the housing serving as a fluid sump; an axle supported by the housing; a hydrostatic transmission disposed in the housing so as to drive the axle, the hydrostatic transmission including a hydraulic pump disposed in the housing, a hydraulic motor disposed in the housing, and a center section disposed in the housing, wherein the hydraulic pump and the hydraulic motor are mounted onto the center section, and wherein the center section is formed therein with a fluid circuit for circulation of fluid between the hydraulic pump and the hydraulic motor, and formed with an outwardly opened hole connected to the fluid circuit; a valve holding member fitted into the hole; and a relief valve connected to the fluid circuit through valve holding member.

Abstract: An articulated vehicle with a working device has a first frame having a prime mover mounted thereon and supporting a first transaxle apparatus. The first transaxle apparatus includes an input shaft receiving power from the prime mover, a pair of first axles, and a hydrostatic transmission. The hydrostatic transmission comprises a variable hydraulic pump, a first hydraulic motor fluidly connected to the hydraulic pump via a fluid passage, and a housing with a port fluidly connected to the fluid passage. The second transaxle apparatus includes a pair of second axles having different lengths and a second hydraulic motor. The second hydraulic motor is fluidly connected to the port. Proximal ends of the first and second frames with respect to the vehicle are coupled to each other so that the first and second frames are rotatable around a vertical axis relative to each other when steered.

Abstract: An integrated hydraulic transaxle (IHT) comprises a hydrostatic transmission (HST), an axle driven by the HST, and a housing incorporating the HST and the axle. The HST includes a variable displacement hydraulic pump driven by a prime mover, and a hydraulic motor fluidly connected to the hydraulic pump. The hydraulic pump has a trunnion type movable swash plate. The internal displacement of the hydraulic motor is larger than the internal displacement of the hydraulic pump so as to increase the hydraulic deceleration activity of the HST. In the IHT, a mechanical deceleration drive train is interposed between the hydraulic motor and the axle. The mechanical deceleration activity of the mechanical deceleration drive train is reduced so far as the increase of the hydraulic deceleration activity of the HST.

Abstract: An articulate vehicle has first and second frames, which are coupled to each other at proximal ends thereof with respect to the vehicle through a coupling part so as to be relatively rotatable around a vertical axis according to steering operation. The first and second frames are distributed at front and rear portions of the vehicle. The first frame supports a first transaxle apparatus having first axles, and the second frame supports a second transaxle apparatus having a pair of second axles. A gearbox is disposed near the coupling part and provided with a pair of mutually drivingly connected horizontal shafts which are variable in relative angles thereof around the vertical axis according to steering operation. One of the horizontal shafts is drivingly connected to a power take-off shaft for extracting output power of a speed-changing arrangement in the first transaxle apparatus. The other of the horizontal shafts is drivingly connected to an input shaft of the second transaxle apparatus.

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: There is provided a pump unit configured to be capable of transmitting a rotational power from a driving power source which is operatively connected thereto to an actuator through a pair of hydraulic fluid lines. The pump unit includes: an input shaft; a hydraulic pump main body; a PTO shaft; a PTO clutch mechanism; an auxiliary pump main body; a suction line; a discharge line; a charge line; a PTO hydraulic fluid line; a pressure-reducing valve; and a resistance valve. The PTO hydraulic fluid line and the charge line are fluidly connected to the primary side and a secondary side of the pressure-reducing valve, respectively.

Abstract: An integrated hydraulic transaxle (IHT) comprises a hydrostatic transmission (HST), an axle driven by the HST, and a housing incorporating the HST and the axle. The HST includes a variable displacement hydraulic pump driven by a prime mover, and a hydraulic motor fluidly connected to the hydraulic pump. The hydraulic pump has a trunnion type movable swash plate. The internal displacement of the hydraulic motor is larger than the internal displacement of the hydraulic pump so as to increase the hydraulic deceleration activity of the HST. In the IHT, a mechanical deceleration drive train is interposed between the hydraulic motor and the axle. The mechanical deceleration activity of the mechanical deceleration drive train is reduced so far as the increase of the hydraulic deceleration activity of the HST.

Abstract: An axle driving system which houses in a housing thereof a hydrostatic transmission, axles, and a driving gear train for connecting output means of the hydraulic transmission and axles, so as to transmit power from a driving source to the hydrostatic transmission and to change the speed, thereby driving the axles. A first chamber therein contains the hydrostatic transmission and a second chamber therein contains the driving gear train. Both the first and second chambers are independent of each other so as to prevent a foreign object, such as iron powder produced in the driving gear train, from entering the hydrostatic transmission. The system includes an L-like-shaped center section on which the hydrostatic transmission is offset such that an imaginary plane which includes a motor mounting surface passes in proximity to the axis of a pump shaft. The pump shaft is disposed perpendicular to the axles. The motor shaft is disposed in parallel thereto.

Abstract: A hydrostatic transmission comprises a housing whose interior space serves as a fluid sump, a pair of first and second fluid passages disposed in the housing, the pair of first and second fluid passages interposed between the hydraulic pump and the hydraulic motor so as to constitute a closed fluid circuit of an HST. A charge fluid passage is disposed in the housing so as to be connected with each of the first and second fluid passages for supplying fluid from the fluid sump into the closed fluid circuit. A drain fluid passage including an orifice is disposed in the housing so as to be connected with at least one of the first and second fluid passages so that, when hydraulic pressure in the at least one of the first and second fluid passages is increased beyond its neutral level, excessive fluid in the at least one of the first and second fluid passages is drained through the drain fluid passage to the fluid sump, thereby expanding the neutral zone of the HST.

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: An axle driving unit having a housing (21,22) for supporting a first axle (17) for mounting thereon a first driving wheel (3L), and a longer second axle (18) for mounting thereon a second driving wheel (3R). The axle driving unit is eccentrically mounted on a body frame (1) in proximity to the first driving wheel (3L). A speed change transmission (T) is disposed in an enlarged region of the housing that extends substantially perpendicularly with respect to the axles (17,18). The axle driving unit can thus be easily disposed to the side of a chute (6) of a rear-discharge type lawn tractor.

Abstract: An axle driving system which houses in a housing thereof a hydrostatic transmission, axles, and a driving gear train for connecting output means of the hydraulic transmission and axles, so as to transmit power from a driving source to the hydrostatic transmission and to change the speed, thereby driving the axles. A first chamber therein contains the hydrostatic transmission and a second chamber therein contains the driving gear train. Both the first and second chambers are independent of each other so as to prevent a foreign object, such as iron powder produced in the driving gear train, from entering the hydrostatic transmission. The system includes an L-like-shaped center section on which the hydrostatic transmission is offset such that an imaginary plane which includes a motor mounting surface passes in proximity to the axis of a pump shaft. The pump shaft is disposed perpendicular to the axles. The motor shaft is disposed in parallel thereto.

Abstract: A pump unit for supply and discharge of hydraulic fluid into and from an actuator upon receiving driving power from a driving source is provided, in which said actuator is fluidly connected to said pump unit via a hydraulic circuit. The pump unit includes an input member operatively connected to the driving source, a first hydraulic pump body operatively connected to the input member, a pump case for accommodating the first hydraulic pump body and forming a hydraulic fluid sump, and a PTO unit accommodated within the pump case. The PTO unit includes a PTO shaft supported by the pump case so as to have an end extending outward from the pump case, and a clutch mechanism for selectively enabling and disabling transmission of driving power from the input member to the PTO shaft.

Abstract: An integrated hydraulic transaxle (IHT) comprises a hydrostatic transmission (HST), an axle driven by the HST, and a housing incorporating the HST and the axle. The HST includes a variable displacement hydraulic pump driven by a prime mover, and a hydraulic motor fluidly connected to the hydraulic pump. The hydraulic pump has a trunnion type movable swash plate. The internal displacement of the hydraulic motor is larger than the internal displacement of the hydraulic pump so as to increase the hydraulic deceleration activity of the HST. In the IHT, a mechanical deceleration drive train is interposed between the hydraulic motor and the axle. The mechanical deceleration activity of the mechanical deceleration drive train is reduced so far as the increase of the hydraulic deceleration activity of the HST.

Abstract: An axle driving unit having a housing including at least two housing parts joined to each other through a joint surface, at least one of the housing parts including a recess formed in a wall thereof. The axle driving unit further includes a pair of hydraulic devices mounted perpendicular to each other on corresponding mounting surfaces of a center section. The center section further includes a portion extending outwardly parallel to the joint surface, the portion being fitted into the recess of the housing part.

Abstract: A vehicle is installed with an integral transaxle apparatus constructed so that a single housing contains left and right axles, a driving hydrostatic transmission (HST) having a variable displacement first hydraulic pump and a first hydraulic motor fluidly connected with each other, a steering HST having a variable displacement second hydraulic pump and a variable displacement second hydraulic motor fluidly connected with each other, and a differential unit differentially connecting the axles with each other so as to be driven regularly or reversely by the output of the driving HST and to differentially drive the axles while receiving the output of the steering HST, wherein the first hydraulic pump receives power of a prime mover and has a first movable swash plate, and the second hydraulic pump receives power of the prime mover independently of the first hydraulic pump and has a second movable swash plate.

Abstract: A hydrostatic transmission, comprising a housing, an interior space of the housing serving as a fluid sump; a center section disposed in the housing so as to be submerged In the fluid sump; a hydraulic pump mounted on the center section in the housing: a hydraulic motor mounted on the center section in the housing, and a pair of first and second fluid passages formed within the center section so as to fluidly connect the hydraulic pump with the hydraulic motor. The second fluid passage has an upwardly slant opening toward the fluid sump. A draining device including a relief valve is provided in the opening of the second fluid passage. When hydraulic pressure in the second fluid passage is not more than a predetermined value but not less than that in the first fluid passage, the relief valve is opened so as to drain fluid from the second fluid passage to the fluid sump, thereby keeping the hydrostatic transmission in neutral.

Abstract: An articulated vehicle with a working device has a first frame having a prime mover mounted thereon and supporting a first transaxle apparatus. The first transaxle apparatus includes an input shaft receiving power from the prime mover, a pair of first axles, and a hydrostatic transmission. The hydrostatic transmission comprises a variable hydraulic pump, a first hydraulic motor fluidly connected to the hydraulic pump via a fluid passage, and a housing with a flexible port fluidly connected to the fluid passage. The second transaxle apparatus includes a pair of second axles having different lengths and a second hydraulic motor. The second hydraulic motor is fluidly connected via piping to a directionally adjustable connection portion of the flexible port. Proximal ends of the first and second frames with respect to the vehicle are coupled to each other so that the first and second frames are rotatable around a vertical axis relative to each other when steered.

Abstract: A pump unit for supply and discharge of hydraulic fluid into and from an actuator upon receiving driving power from a driving source is provided, in which said actuator is fluidly connected to said pump unit via a hydraulic circuit. The pump unit includes an input member operatively connected to the driving source, a first hydraulic pump body operatively connected to the input member, a pump case for accommodating the first hydraulic pump body and forming a hydraulic fluid sump, and a PTO unit accommodated within the pump case. The PTO unit includes a PTO shaft supported by the pump case so as to have an end extending outward from the pump case, and a clutch mechanism for selectively enabling and disabling transmission of driving power from the input member to the PTO shaft.

Abstract: An axle driving apparatus consisting of a housing for compactly housing inner portions of axles, a hydrostatic transmission, and a transmitting mechanism for transmitting power to the axles from an output shaft of the hydrostatic transmission. The housing is partitioned by an internal wall into a chamber containing the hydrostatic transmission and a chamber containing the other transmitting mechanisms. The housing is filled with oil in common with both chambers. A trunnion for changing the output rotation of the hydrostatic transmission is disposed in parallel to the axles. A shock absorber is provided to prevent abrupt speed change. A differential locking device is attached to the differential gear to thereby improve the straightforward running capacity of the vehicle.