US 6,119,802 AGranted

Hydraulic drive system for a vehicle

AssigneeAnser, Inc.

InventorEdwin E. Puett, Jr.

Life of this patent

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Abstract

A hydraulic drive system for a vehicle includes a pressurizing circuit and a working circuit. The pressurizing circuit incorporates a pump driven by a prime mover having a nominal horsepower rating. The prime mover is either shut off or idled when the pressure sensed within the pressurizing circuit is within a desired range and run at an optimum high RPM range when the pressure falls below the desired range. At least one accumulator is provided in the pressurizing circuit. The working circuit includes a plurality of motors for driving at least one vehicle wheel and a motor control valve arrangement which isolates one or more motors from the flow of pressurized fluid while deactivated and drives the motors while activated. As vehicle speed increases and drive resistance decreases, the number of motors propelling the vehicle is progressively reduced. A flow control valve alters flow to the motors.

Claims18

Dependent claims

A fluid drive system in a vehicle comprising:

a prime mover including a rotatable driveshaft;
an adjustable vehicle control member;
a reservoir for maintaining a supply of working fluid;
a working circuit including:
a plurality of fluid motors, each of said motors being drivingly connected to at least one wheel of the vehicle and including first and second fluid ports;
a first working conduit system fluidly connecting to the first fluid port of each of said motors, said first working conduit system including a main working pressure line;
a second working conduit system fluidly connected to the second fluid port of each of said motors, said second working conduit system terminating, within said working circuit, in a common, auxiliary working pressure line;
motor control valve means interposed between said motors and at least one of said main and auxiliary working pressure lines for establishing fluid communication between at least one of said motors and at least one of said main and auxiliary working pressure lines in a working position and interrupting fluid communication between said motors and said at least one of said main and auxiliary working pressure lines in an isolating position, wherein said plurality of fluid motors are arranged with respect to said first and second working conduits, parallel to one another and at least two of said plurality of fluid motors are drivingly connected to a common output shaft, said common output shaft being drivingly connected to at least one wheel of the vehicle;
a pressurizing circuit including:
a pump drivingly coupled to the driveshaft of said prime mover, said pump including an inlet in fluid communication with said reservoir and an outlet;
an accumulator in fluid communication with the outlet of said pump;
a main pressure supply line in fluid communication with said accumulator, said main pressure supply line including a terminal portion located downstream of said accumulator;
an adjustable flow control valve located in said main pressure supply line downstream of said accumulator, said adjustable flow control valve being linked to said adjustable vehicle control member such that selective movement of said adjustable vehicle control member repositions said adjustable flow control valve;
directional flow control valve means interconnected between said main pressure supply line, said main working pressure line, said auxiliary working pressure line and said reservoir for controlling the flow of working fluid between said working and pressurizing circuits;
and
means for shifting said motor control valves means between said working and isolating positions.

13 more elements

A fluid drive system in a vehicle comprising:

a plurality of fluid, wheel driving motors, with at least two of said plurality of fluid motors being drivingly connected to at least one common wheel of the vehicle;
motor control valve means for controlling a number of said plurality of fluid motors used to drive the vehicle;
a prime mover including a rotatable driveshaft;
a regulating unit adapted to control an operating speed of said prime mover;
a reservoir housing a source of working fluid;
a pump drivingly coupled to the driveshaft of said prime mover, said pump being in fluid communication with said source of working fluid and a pressurizing circuit leading to said plurality of fluid motors;
a flow control valve interposed in said pressurizing circuit between said pump and said plurality of fluid motors;
a first relay unit for detecting a first operating condition of said fluid drive system associated with an available amount of working fluid in said pressurizing circuit between said pump and said flow control valve and signalling said regulating unit to control the operating speed of said prime mover;
and
a second relay unit for detecting a second operating condition of said fluid drive system associated with a flow of working fluid through said flow control valve to said plurality of fluid motors and signalling the second operating condition to said motor control valve means to control the number of said plurality of fluid motors used to drive the vehicle.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/930,306Filed 22 Oct 1997 · continuation in part
Priority: 28 Apr 1995
Granted: 19 Sep 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

F16H 61/4096
Fluid exchange between hydrostatic circuits and external sources or consumers: with pressure accumulators
B60K 17/10
Characterised by arrangement, location or kind of gearing: of fluid gearing
B60K 17/356
For driving both front and rear wheels, e.g. four wheel drive vehicles: having fluid or electric motor, for driving one or more wheels
F16H 61/44
Hydrostatic: with more than one pump or motor in operation