Hydraulic drive system
First Claim
1. A hydraulic transmission comprising a first rotary hydraulic machine to be driven by a prime mover, at least one hydraulic drive unit, a hydraulic conduit connecting said first machine and said drive unit, a control operable to control delivery of fluid between said first rotary machine and said drive unit, an additional variable capacity machine mechanically connected to said first machine to supply fluid to an accumulator and a sensor to determine variations in load imposed by said first machine on said prime mover, said control operable to vary the capacity of said additional machine in response to variations in said load.
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0 Petitions
Accused Products
Abstract
A hydraulic drive system for an actuator uses a pair of pressure compensated hydraulic machines to control flow to and from the drive chambers of the actuator by varying the controlled pressure of one of the machines. The machines are mechanically coupled to permit energy recovery and charge an accumulator to store supplies energy. The drive system may be combined with other services including a transmission for incorporation in a vehicle. The transmission uses a pressure compensated supply and torque control of the wheels.
108 Citations
27 Claims
- 1. A hydraulic transmission comprising a first rotary hydraulic machine to be driven by a prime mover, at least one hydraulic drive unit, a hydraulic conduit connecting said first machine and said drive unit, a control operable to control delivery of fluid between said first rotary machine and said drive unit, an additional variable capacity machine mechanically connected to said first machine to supply fluid to an accumulator and a sensor to determine variations in load imposed by said first machine on said prime mover, said control operable to vary the capacity of said additional machine in response to variations in said load.
- 8. A method of operating a hydraulic transmission having a first rotary hydraulic machine to be driven by a prime mover, at least one hydraulic drive unit, a hydraulic conduit connecting said first machine and said drive unit, a control operable to control delivery of fluid between said first rotary machine and said drive unit, an additional variable capacity machine mechanically connected to said first machine to supply fluid to an accumulator and a sensor to monitor load imposed by said first machine on said prime mover, said method comprising the steps of monitoring said load and varying the capacity of said additional machine in response to variations maintain said speed at said desired level.
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13. A hydraulic drive system comprising:
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a hydraulic transmission comprising a first rotary hydraulic machine to be driven by a prime mover, at least one hydraulic drive unit, a hydraulic conduit connecting said first machine and said drive unit, a control operable to control delivery of fluid between said first rotary hydraulic machine and said drive unit, and, a hydraulic actuator having a pair of chambers separated by a drive member and disposed to apply a motive force in opposite directions to said drive member, each chamber being connected to a respective one of a pair of variable capacity machines, at least one of which is operable in a pumping mode to supply fluid to one of said chambers and at least the other of which is operable in a motoring mode to consume fluid expelled from the other of said chambers, each of said machines having a pressure compensating control to condition said machine to maintain a respective predetermined pressure in said chambers, a mechanical transmission to connect said first rotary hydraulic machine and said variable capacity machines to transfer energy therebetween, and an external control operable to modulate said predetermined pressure in at least one of said variable capacity machines and thereby vary the motive forces acting on said drive member. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A hydraulic drive system comprising:
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a pair of actuators, each having a pair of chambers separated by a drive member and disposed to apply a motive force in opposite directions to said drive member, each chamber being connected to a respective variable capacity machine, each of said actuators being associated with at least one variable capacity machine which is operable in a pumping mode to supply fluid to a chamber of a respective actuator, and being associated with at least one other variable capacity machine which is operable in a motoring mode to consume fluid expelled from the other of said chambers of the respective actuator, each of said variable capacity machines having a pressure compensating control to condition said machine to maintain a respective predetermined pressure in said chambers, a mechanical transmission to connect said variable capacity machines to transfer energy therebetween, and, an external control operable to modulate said predetermined pressure in at least one of said machines and thereby vary the motive forces acting on a drive member of said actuator associated with said one of said machines. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification