Methods and systems for a hydromechanical transmission are provided. In one example, the method includes responsive to rotation of a portion of a mechanical assembly induced by cranking of an engine, blocking an output shaft of the hydromechanical transmission via joint engagement of a forward drive clutch and a reverse drive clutch. The method further includes pressurizing a hydrostatic assembly while the forward drive clutch and the reverse drive clutch remain jointly engaged, where the mechanical assembly is coupled in parallel with the hydrostatic assembly.

Methods and systems for a hydromechanical transmission are provided herein. In one example, a vehicle system is provided that includes a hydromechanical transmission with a power-take off (PTO) that is designed to rotationally couple to an implement. The vehicle system further includes an engine coupled to the hydromechanical transmission and a power-management control unit configured to, during a drive or coast condition, cause the power-management control unit to: determine a net available power for the hydromechanical transmission and manage a power flow between the hydromechanical transmission, a drive axle, and the implement based on the net available power.

Systems and methods for controlling transmissions having CVTs are disclosed with multiple modes and gearing arrangements for range enhancements, where embodiments include synchronous shifting to allow the transmission to achieve a continuous range of transmission ratios, while minimizing “empty” cycling of the CVT during mode shifts. Embodiments provide for wide ratio range and performance and efficiency flexibility, while maximizing CVT usage through synchronous shifting.

A transmission (21) as a power transmission device for a vehicle comprises an input shaft (22), an output shaft (23), and a planetary continuously variable transmission mechanism (31). The planetary continuously variable transmission mechanism (31) comprises a planetary gear mechanism (32), a pump side clutch (33), a hydraulic pump (36), a hydraulic motor (38), and a motor side clutch (40). The hydraulic pump (36) and the hydraulic motor (38) are connected via a pair of main lines (37A, 37B). When the transmission (21) is switched from a traveling state to a neutral state, at least one clutch (33, 40) of the pump side clutch (33) and the motor side clutch (40) is released.

A hydro-mechanical hybrid transmission device with an energy management mechanism includes an input member, a mechanical transmission mechanism, an energy management mechanism, a power output mechanism, an output member, a convergence mechanism, a start mechanism, a hydraulic transmission mechanism, a clutch assembly, and a brake assembly. The clutch assembly connects the input member to the mechanical transmission mechanism, the power output mechanism, and the hydraulic transmission mechanism, and connects the energy management mechanism to the mechanical transmission mechanism and the power output mechanism. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member and/or the power output mechanism, between the energy management mechanism and the output member and/or the power output mechanism, and between the energy management mechanism together with the input member and the output member and/or the power output mechanism.

A power-split drive train for a working machine having a main drive element, drive output shafts (Ab1, Ab2, Ab3), and a continuous power-split transmission with three drive units (2a, 2b, 2c). The transmission enables all three output shafts to be operated at the same time with rotational speed variability. A first drive unit (2a) has two energy converters while second and third drive units (2b, 2c) each comprise one energy converter. All four energy converters are functionally connected to an electric line. The first unit (2a) is connected, via a first shaft, to the main drive element and, via a second shaft, to output shaft (Ab1). The first unit (2a) is connected to drive unit (2b) which is connected, via a third shaft, to output shaft (Ab2). The first drive unit (2a) is connected to drive unit (2c) which is connected, via a fourth shaft, to output shaft (Ab3).

A powertrain system in a machine includes a transmission, and a transmission drive mechanism coupled between the transmission and an engine. The transmission drive mechanism includes a split path architecture where a first input gear receives a torque input from a driveshaft and a second input gear receives a torque input from a variator. The transmission drive mechanism is thereby structured to operate the transmission at a range of speeds that is not dependent upon a speed of the engine, enabling the engine to operate at an engine speed set point or with an optimum engine speed range.

An HST of the present invention includes a main plate and a sub-plate supporting a center section, a pump-side swash plate holder and a motor-side swash plate holder by their inner surfaces facing each other. The main plate is provided with an extended region that extends farther outward in a planar direction of the main plate than an installation space of the center section, the pump-side swash plate holder and the motor-side swash plate holder and than the sub-plate as viewed along a direction in which the main plate and the sub-plate face each other.

A variable speed transmission having a plurality of tilting balls and opposing input and output discs is illustrated and described that provides an infinite number of speed combinations over its transmission ratio range. The use of a planetary gear set allows minimum speeds to be in reverse and the unique geometry of the transmission allows all of the power paths to be coaxial, thereby reducing overall size and complexity of the transmission in comparison to transmissions achieving similar transmission ratio ranges.

A hydrostatic drive system (1) with a hydrostatic pump (3) driven by a drive motor (2) and connected in a closed circuit with a hydrostatic motor (4). The hydrostatic motor (4) is connected with a consumer (5). The closed circuit is formed by a first hydraulic connection (6a) and a second hydraulic connection (6b). A pressure accumulator device (30) can be connected with the two hydraulic connections (6a, 6b) for the storage of energy and the output of energy. The pressure accumulator device (30) is a double piston accumulator (31) having a high-pressure-side pressure chamber (32) and a low-pressure-side pressure chamber (33). The high-pressure-side pressure chamber (32) can be connected with one of the two hydraulic connections (6a, 6b) of the closed circuit and simultaneously the low-pressure-side pressure chamber (33) can be connected with the respective other hydraulic connection (6b, 6a) of the closed circuit.