VEHICLE DRIVE WITH TWO ELECTRIC MOTORS

• US 3,870,935 A
• Filed: 02/13/1973
• Issued: 03/11/1975
• Est. Priority Date: 08/06/1971
• Status: Expired due to Term

• Current Assignee: Siegfried Puschel, Theodor Abels
• Original Assignee: Siegfried Puschel, Theodor Abels
• Inventors: Abels, Theodor, Puschel, Siegfried
• Primary Examiner(s): Lynch, T. E.
• Application Number:
  US05/332,226
• Time in Patent Office: 756 Days
• Field of Search: 318/8,52,85,345 180/6.5
• US Class Current: 318/52
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 2200/42 Fork lift trucks
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/429 Current
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 7/006 Dynamic electric braking by reversing current, i.e. plugging
• CPC Class Codes: Y02P 90/60 Electric or hybrid propulsion means for production processes
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An electric-powered vehicle, e.g. of the fork-lift, plantutility or other type in which a pair of electric motors are driven by power derived from a rechargeable battery, has two motors for driving wheels on the opposite sides of the vehicle and capable of differential operation. The two motors are connected in parallel to a single pulse control (pulse generator) and are selectively excited or de-energized or accommodate differential action during turns of the vehicle, but are connected jointly to the single pulse control when no differential action is required.

Claims

1. In an electrically operated vehicle having a pair of driving wheels on opposite sides of the vehicle, a source of electric current, and respective motors operatively connected to said wheels, the improvement which comprises a control circuit connected between said source and said motors and including driving-pulse generating means in circuit with said source, respective switches connecting said generating means to said motors in parallel and operable to cut off one of said motors selectively to enable differential rotation of said wheels, each of said motors being a series-wound direct current motor having a field winding and an armature connected in series with one another, each of said switches being connected in series with the field winding and armature of a respective motor at one side thereof, the series network of field winding, switch and armature of both motors being connected together on one side thereof via a common conductor, a sensor provided in circuit with said common conductor and connected in a feedback path to said pulse generating means each of said field windings including a pair of field coils respectively excitable for driving the respective motor in opposite senses, each switch associated with the respective motor including a switch member in series with a coil of the respective pair, a free running diode connected between said common conductor and said pulse generating means across at least one of said motors, and at least one armature diode connected between said common conductor and across at least one of said armatures between said one of said armatures and the respective field winding.

2. The improvement defined in claim 1 wherein said vehicle has steerable wheels further comprising means responsive to the orientation of said steerable wheels for selectively operating said switches.

3. The improvement defined in claim 1 wherein a respective armature diode is provided across each of said armatures between said common conductor and a respective junction of each field windIng with the respective armature.

4. The improvement defined in claim 1, further comprising a bridge network tied to each of said motors between a respective armature and its field winding and connected to said armature diode whereby said armature diode is effective for both said motors.

5. The improvement defined in claim 4, further comprising respective cutout switches in said network between the armature diode and the junction between each armature and the respective field winding and open-circuitable in conjunction with the respective switch in series with the field winding of the respective motor.

6. The improvement defined in claim 1 wherein said pulse generating means includes a single pulse generator and both said motors and a pair of branch conductors connected in common to said pulse generator, said free running diode being connected between said common conductor and both said branch conductors, each of said branch conductors being in series with a respective one of said switches, a pair of such armature diodes being provided across each of said armatures between said common conductor and a junction between each armature and the respective field winding.

7. The improvement defined in claim 1 wherein said pulse generating means includes a respective pulse generator assigned to each of said motors, and a sensor connected between said motors for selectively controlling said pulse generator.

8. The improvement defined in claim 7 wherein said sensor connected between said motors has an input connected to each motor between the respective armature and field winding.

9. The improvement defined in claim 8 wherein said pulse generating means further comprises an amplifier receiving an input from the sensor connected between both said motors and from said sensor connected to said common conductor and having outputs connected to said pulse generators for selectively applying feedback control signals thereto.