An integrated hybrid energy recovery and storage system for recovering and storing energy from multiple energy sources is disclosed. The system includes an accumulator unit having a high pressure accumulator and a low pressure accumulator. At least one piston is mounted for reciprocation in the high pressure accumulator. The accumulator unit is configured to receive, store, and transfer energy from the hydraulic fluid to the energy storage media. The system further includes two or more rotational directional control valves, in which at least one rotational directional control valve is positioned on each side of the accumulator unit. Each rotational directional control valve includes multiple ports. The system also includes two or more variable displacement hydraulic rotational units. At least one variable displacement hydraulic rotational unit is positioned adjacent each of the rotational directional control valves.

A method of drivingly engaging a first motor of a dual motor drive unit with an output shaft driven by a second motor of the dual motor drive unit includes actuating a clutching device for drivingly engaging the first motor with the output shaft. Next, a rotational speed of the first motor is synchronized with a rotational speed of the output shaft. When the rotational speed of the first motor and the rotational speed of the output shaft are synchronized, an output torque of the first motor is reduced. When the clutching device drivingly engages the first motor with the output shaft, the output torque of the first motor is increased. The invention further relates to a dual motor drive unit for carrying out the method.

A method of drivingly engaging a first motor of a dual motor drive unit with an output shaft driven by a second motor of the dual motor drive unit includes actuating a clutching device for drivingly engaging the first motor with the output shaft. Next, a rotational speed of the first motor is synchronized with a rotational speed of the output shaft. When the rotational speed of the first motor and the rotational speed of the output shaft are synchronized, an output torque of the first motor is reduced. When the clutching device drivingly engages the first motor with the output shaft, the output torque of the first motor is increased. The invention further relates to a dual motor drive unit for carrying out the method.

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.

A hydrostatic drive system is disclosed which allows for simpler and more robust control of hydraulic vibration. The system comprises first and second hydraulic drive units and a variable damping device. At least the first hydraulic drive unit is a variable displacement type and comprises a displacement control. The variable damping device comprises at least one variable element. The system comprises a first linkage apparatus between the displacement control and the variable element and is operable to control the variable element in accordance with the displacement of the displacement control.

A counter balance valve (71L) is located between a directional control valve (23) and a hydraulic motor (32L) and provided on the way of a pair of supply/discharge lines (25A, 25B). The counter balance valve (71L) allows a spool (72L) to be displaced axially based on a pressure difference between the supply/discharge lines (25A, 25B). The counter balance valve (71L) includes a communicating passage (73L) for communicating the supply/discharge lines (25A, 25B) when the displacement of the spool (72L) exceeds a predetermined amount (X.sub.CM), based on a pressure difference between the supply/discharge lines (25A, 25B). The communicating passage (73L) is provided in the spool (72L) of the counter balance valve (71L).

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.

A transmission case includes: a main transmission input shaft to which the driving force is transmitted from the engine; and a main transmission output shaft fit on the main transmission input shaft in a relatively rotatable manner. The main transmission input shaft is provided with a hydraulic pump unit, a cylinder block, and a fixed capacity hydraulic motor unit, forming a hydraulic mechanical transmission, arranged in series. Shifted driving force is transmitted to the main transmission output shaft via the fixed capacity hydraulic motor unit. The transmission case includes a planetary gear mechanism and a transmission shaft with which the shifted driving force via the main transmission output shaft and the combined driving force via the planetary gear mechanism can be transmitted.

A transmission case includes: a main transmission input shaft to which the driving force is transmitted from the engine; and a main transmission output shaft fit on the main transmission input shaft in a relatively rotatable manner. The main transmission input shaft is provided with a hydraulic pump unit, a cylinder block, and a fixed capacity hydraulic motor unit, forming a hydraulic mechanical transmission, arranged in series. Shifted driving force is transmitted to the main transmission output shaft via the fixed capacity hydraulic motor unit. The transmission case includes a planetary gear mechanism and a transmission shaft with which the shifted driving force via the main transmission output shaft and the combined driving force via the planetary gear mechanism can be transmitted.