Abstract: An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

Abstract: An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

Abstract: A hydraulic apparatus is provided with a return to neutral mechanism for returning a trunnion control bracket arm to a neutral position. The return to neutral mechanism comprises a pair of springs, one spring connecting a fixed bracket to a first rotatable bracket and the other spring connecting the fixed bracket to a second rotatable bracket. The mechanism uses springs with different spring constants and the springs are attached to the brackets in a single plane.

Abstract: A hydrostatic transmission includes a hydraulic pump, a top housing that houses the hydraulic pump, and a hydraulic motor. An endblock sub-assembly has a pump running face for interfacing with the hydraulic pump, and a motor connection portion for interfacing with a hydraulic motor. The enblock sub-assembly forms a porting manifold for communicating hydraulic fluid from the hydraulic pump to the hydraulic motor. The hydraulic motor includes an internal rotor set, and the hydraulic motor is secured to the endblock sub-assembly in a manner that permits rotation of the rotor set. The top housing is fixed to the endblock sub-assembly such that the housing and endblock sub-assembly form a reservoir for the hydraulic fluid. The motor connection portion of the endblock sub-assembly supports the hydraulic motor externally to the top housing. The hydrostatic transmission is suitable for incorporation into various light vehicle categories, including zero-turn radius vehicles.

Abstract: A return to neutral mechanism is provided for hydraulic apparatuses such as motors/pumps that utilize a swashplate and a trunnion arm to control flow. The return to neutral mechanism includes two rotating brackets which have ends aligned to a single plane. Two springs are utilized and attached to the ends of the two rotating brackets giving the force mechanism the ability apply the force in a direct path, reducing friction, increasing life, and improving accuracy. This design is an “x” type mechanism, the force arms are in-line and do not cross, the force is applied equally on both sides of the fulcrum and therefore balanced. The mechanism can be can be used with compression springs, tension springs, torsion springs, or leaf springs.

Abstract: A hydrostatic transmission includes a hydraulic pump, a top housing that houses the hydraulic pump, and a hydraulic motor. An endblock sub-assembly has a pump running face for interfacing with the hydraulic pump, and a motor connection portion for interfacing with a hydraulic motor. The enblock sub-assembly forms a porting manifold for communicating hydraulic fluid from the hydraulic pump to the hydraulic motor. The hydraulic motor includes an internal rotor set, and the hydraulic motor is secured to the endblock sub-assembly in a manner that permits rotation of the rotor set. The top housing is fixed to the endblock sub-assembly such that the housing and endblock sub-assembly form a reservoir for the hydraulic fluid. The motor connection portion of the endblock sub-assembly supports the hydraulic motor externally to the top housing. The hydrostatic transmission is suitable for incorporation into various light vehicle categories, including zero-turn radius vehicles.

Abstract: A hydraulic apparatus is provided with a return to neutral mechanism for returning a trunnion control bracket arm to a neutral position. The return to neutral mechanism comprises a pair of springs, one spring connecting a fixed bracket to a first rotatable bracket and the other spring connecting the fixed bracket to a second rotatable bracket. The mechanism uses springs with different spring constants and the springs are attached to the brackets in a single plane.