Motor control system for a linearly reciprocating load device such as automotive vehicle closure including sun roof

• US 4,220,900 A
• Filed: 06/16/1978
• Issued: 09/02/1980
• Est. Priority Date: 06/16/1978
• Status: Expired due to Term

• Current Assignee: Sky-Top Sunroofs Limited
• Original Assignee: Sky-Top Sunroofs Limited
• Inventors: Mintz, Irwin H.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Redman, John W.
• Application Number:
  US05/916,206
• Time in Patent Office: 809 Days
• Field of Search: 296/137 E, 296/137 F, 296/137 G, 318/255, 318/256, 318/261, 318/264, 318/266, 318/275, 318/445, 318/446, 318/447, 318/450, 318/452, 318/453, 318/466, 318/467, 318/468, 318/469, 318/474, 318/476 , 318/471-473
• US Class Current: 318/266
• CPC Class Codes: H02H 3/087 for dc applications
• CPC Class Codes: H02H 7/0851 for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal
• CPC Class Codes: H02H 7/0855 avoiding response to transient overloads, e.g. during starting

Abstract

A system is provided to control a load responsive to a maximum load condition to disable the load when the maximum load condition exists, the control being altered first to provide a period of non-response during load start up and secondly to provide temperature compensation over a very wide temperature range and more particularly where the load device is a motor means for linearly reciprocating a closure member such as a sun roof, a window or a door, particularly for a vehicle such as an automotive vehicle.

Claims

1. A control system for starting and stopping a load device having a predetermined maximum steady state value of load current and a starting current substantially in excess of said steady state load current, a load circuit power source, means for providing a reference voltage which is indicative of said maximum steady state value of load current, said means comprising a resistor network including resistor means whose voltage drop is indicative of said predetermined value of steady state current, and a circuit network comprising temperature compensating means for maintaining accuracy of said reference voltage through a wide range of temperature variation, means for limiting the temperature response at the lower limit of the temperature range and means for limiting the temperature response at the high end of the temperature range, a load resistor in series with said load device, the voltage drop in said load resistor being indicative of the current flowing in said load device, means for comparing said reference voltage and said voltage drop across said load resistor to produce a difference voltage, means responsive to said difference voltage to disable said load device when the steady state current of said load device exceeds the predetermined maximum steady state value and means for delaying the response of said difference voltage responsive means for a predetermined time so that the control system is not responsive to the starting current of said load device.

2. A control system as set forth in claim 1, wherein said delay means comprises a resistor-capacitor combination.

3. A motor control system for a motor adapted to drive a load and to be started and run in either forward or reverse direction and to be stopped at definite limits of travel of the load, a motor, means for disabling said motor when a predetermined value of torque is exceeded as measured by the motor load current, a power source for said motor, a reversing switch for controlling the energization of said motor for rotation in either forward or reverse direction, a load resistor in series with said motor so that the voltage drop across said load resistor is indicative of said motor load current and hence of the resultant motor torque, a resistor network for providing a reference voltage which is indicative of the maximum steady state motor current which corresponds to the maximum permissible motor torque, said resistor network comprising a resistor whose voltage drop corresponds to the maximum steady state motor current, and a circuit network comprising temperature compensating means for maintaining accuracy of said reference voltage through a wide range of temperature variation, means for limiting the temperature response at the lower limit of the temperature range and means for limiting the temperature response at the high end of the temperature range, comparator means for comparing said reference voltage and the voltage drop across said load resistor to produce a difference voltage, means responsive to said difference voltage to disable said motor when the steady state motor current exceeds the value corresponding to said maximum value of motor torque and means for delaying the response of said difference voltage responsive means for a predetermined time so that the control system is not responsive to the starting current of said motor.

4. A motor control system as set forth in claim 3, including means connected to both of the terminals of said motor for deriving a voltage of fixed polarity regardless of how said motor is energized for either forward or reverse operation to be applied to said comparator means.

5. A motor control system as set forth in claim 4, wherein said delaying means comprises a resistor-capacitor combination.

6. A linearly reciprocating closure control system including a closure member having a terminal open position and a terminal closed position, a transmission, drive means for said closure member comprising a motor which drives said closure member through said transmission, a control system for said motor comprising a reversing switch which energizes said motor to rotate in either a forward or a reverse direction to drive said closure member to either a terminal open or a terminal closed position, means for disabling said motor when a predetermined value of torque is exceeded as measured by the motor load current, a load resistor in series with said motor so that the voltage drop across said load resistor is indicative of said motor load current and hence of the motor torque, a resistor network for providing a reference voltage which is indicative of the maximum steady state motor current which corresponds to the maximum permissible motor torque, said resistor network comprising a resistor whose voltage drop corresponds to the maximum steady state motor current, and a circuit network comprising temperature compensating means for maintaining accuracy of said reference voltage through a wide range of temperature variation, means for limiting the temperature response at the lower limit of the temperature range and means for limiting the temperature response at the high end of the temperature range, comparator means for comparing said reference voltage and the voltage drop across said load resistor to produce a difference voltage, means responsive to said difference voltage to disable said motor when the steady state motor current exceeds the value corresponding to the maximum value of motor torque thereby to stop said closure member at the position where an obstruction comes into contact with said closure member and means for delaying the response of said difference voltage responsive means for a predetermined time so that the control system is not responsive to the starting current of said motor.

7. A linearly reciprocating closure control system as set forth in claim 6, wherein said transmission comprises gearing driving a screw member which engages a drive nut which is secured to said closure member.

8. A linearly reciprocating closure control system as set forth in claim 7, wherein said closure member is a sun roof for an automobile.