Dual-motor electric drive system for vehicles
First Claim
1. An electric drive system for propelling a track-laying vehicle through both a low speed range and a high speed range to a desired maximum vehicle speed, said drive system comprising:
- first and second electric propulsion motors capable of delivering independent propulsion forces;
said first and second electric propulsion motors each having a maximum speed;
left and right drive tracks;
a final drive system for transferring propulsion forces to the drive tracks;
a predetermined transition speed less than the maximum vehicle speed delineating the transition from the low speed range to the high speed range of the vehicle;
a first drive ratio is provided between said first propulsion motor and said final drive system;
said first drive ratio assures that said first propulsion motor reaches its maximum speed when said vehicle is at its maximum speed;
a second drive ratio is provided between said second propulsion motor and said final drive system;
said second drive ratio assures that said second propulsion motor reaches its maximum speed at approximately said transition speed;
the relationship of said first and second drive ratios effecting multiplication of the output torque from said second propulsion motor to said final drive system at speeds lower than said transition speed;
said first propulsion motor operatively connected to said final drive system to provide the desired maximum vehicle speed; and
,means to engage said second propulsion motor to said final drive system to provide the output torque from said second propulsion motor to said final drive when torque in addition to that supplied by said first propulsion motor is required at speeds below said transition speed;
means to disengage said second propulsion motor from said final drive system at said transition speed when the output torque from said first propulsion motor is sufficient for said final drive system to propel the vehicle in the high speed range.
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Accused Products
Abstract
A dual-motor electric drive system is particularly suited for driving track-laying vehicles. The propulsion motors of the drive system are each individually selected to provide the speed and torque for selected portions of the operational requirements of the vehicle. The electric drive system utilizes a primary motor to provide the maximum speed requirements and a secondary motor to provide the high torque requirements for low speed operation. The primary and secondary propulsion motors are interconnected by a predetermined drive ratio so that the secondary motor provides torque until it attains a maximum predetermined speed whereupon it is disconnected from the primary motor.
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Citations
13 Claims
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1. An electric drive system for propelling a track-laying vehicle through both a low speed range and a high speed range to a desired maximum vehicle speed, said drive system comprising:
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first and second electric propulsion motors capable of delivering independent propulsion forces; said first and second electric propulsion motors each having a maximum speed; left and right drive tracks; a final drive system for transferring propulsion forces to the drive tracks; a predetermined transition speed less than the maximum vehicle speed delineating the transition from the low speed range to the high speed range of the vehicle; a first drive ratio is provided between said first propulsion motor and said final drive system; said first drive ratio assures that said first propulsion motor reaches its maximum speed when said vehicle is at its maximum speed; a second drive ratio is provided between said second propulsion motor and said final drive system; said second drive ratio assures that said second propulsion motor reaches its maximum speed at approximately said transition speed; the relationship of said first and second drive ratios effecting multiplication of the output torque from said second propulsion motor to said final drive system at speeds lower than said transition speed; said first propulsion motor operatively connected to said final drive system to provide the desired maximum vehicle speed; and
,means to engage said second propulsion motor to said final drive system to provide the output torque from said second propulsion motor to said final drive when torque in addition to that supplied by said first propulsion motor is required at speeds below said transition speed; means to disengage said second propulsion motor from said final drive system at said transition speed when the output torque from said first propulsion motor is sufficient for said final drive system to propel the vehicle in the high speed range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification