JPH0373498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a retractable automotive lighting system, and more particularly to a control device for operating a motor-driven headlamp carrier.

Systems of the type described above typically include an electric motor connected to a movable headlamp carrier through a suitable linkage and a control for raising or lowering the headlamp carrier in response to operation of a headlamp switch by the vehicle operator. Including equipment. When the headlamp switch is placed in the ON position, the motor is energized to move the headlamp carrier to the upper limit position that fully exposes the headlamp. When the headlamp switch is placed in the OFF position, the motor is energized in the opposite direction to move the headlamp carrier to a lower limit position that completely covers the headlamp.

Systems of the type described above additionally require a device for stopping the headlamp carrier and interrupting the energization of the motor when the headlamp carrier reaches its upper or lower limit position. In the prior art, two different devices were used: a position sensing device and a torque sensing device.

In the position sensing device, a limit switch is provided opposite the upper or lower limit position of the headlamp carrier, which interrupts the energization of the motor when the headlamp carrier reaches the limit position. When the motor is de-energized, the headlamp carrier stops and remains in that position until the motor is re-energized to move the carrier to the other limit position. Although this mechanism is relatively simple, accurate positioning of the headlamp carrier is difficult due to carrier and motor slippage that occurs after motor energization is interrupted.

In the torque limiting mechanism, a mechanical stop is provided at a position to engage the headlamp carrier when the carrier reaches its upper or lower limit position, thereby ensuring accurate positioning of the headlamp. The torque limit switch interrupts energization of the motor when the output torque of the motor exceeds a reference amount. As a result, the energization of the motor will be interrupted after the headlamp carrier has been moved into engagement with the corresponding stop. A detailed description of such systems is given in the 1982 Pontiac Firebird Service Manual.

The present invention provides an improved method and apparatus for controlling the operation of a motor-driven headlamp carrier, in which the motor engages the carrier with a fixed mechanical stop that defines its travel limit position. It is biased to move and the engagement of the carrier with this stop is detected without the use of a limit switch mechanism. In the present invention, whether or not the motor is rotating is determined by detecting the motor counter EMF related voltage determined by the counter EMF (back electromotive force) from the motor and the battery voltage using an electronic control device. It is designed to make a judgment and stop the motor. In other words, when the motor counter EMF drops to almost 0, the voltage related to the motor counter rises to almost the battery voltage, so by detecting this rise, the headlamp carrier moves to a position where it engages with the mechanical stop. As a result, it can be determined that the motor has stopped rotating, and a stop signal can be outputted to stop the power supplied to the motor.

An oscillator mechanism within the controller outputs a series of pulses to energize the motor, which are interrupted to interrupt energizing the motor in response to generation of the pulse stop signal. To start the motor operation,
By energizing the motor independently of the oscillator mechanism in the controller for a period sufficient to provide motor energization to substantially increase the motor counter EMF above zero. The energization of the motor is then controlled by the oscillator mechanism and counter EMF detection mechanism as described above. Since the above-described control is performed, the motor output torque is limited only when the motor is stopped. However, in systems using torque limit switches, the torque reference is set to the lowest expected system operating voltage, and the battery voltage, and therefore the motor energization, is reduced when the motor torque provided is relatively low. It is necessary to ensure interruption. In other words, the control system of the present invention allows the use of smaller and lighter electric motors than would otherwise be possible.

Operation of the motor is initiated in response to operation of a headlamp switch by the driver, and the motor is deenergized independently of the counter EMF detection mechanism after a predetermined period of time. This predetermined period is longer than the period required to perform a full operation of the carrier, and thus prevents the motor from continuing to operate when the motor is disconnected from the headlamp carrier.

The present invention further provides a fail-safe mode of operation when motor energization is inconsistent with that indicated by the headlamp switch position. If the motor is energized to lower the headlamp when the headlamp switch is not in the OFF position, energization of the motor is discontinued to interrupt operation of the headlamp carrier. When the headlamp switch is turned to the OFF position,
Normal operation resumes.

Turning to a more detailed explanation of Figure 1, reference numerals
10 indicates the right side headlamp assembly of the automobile. A left headlamp assembly (not shown) is provided on the opposite side of the vehicle in a conventional manner. The headlamp assemblies are generally identical, and the following description of the right-hand headlamp assembly 10 applies equally to the left-hand headlamp assembly. Headlamp assembly 10
includes a movable carrier 12 pivotally mounted about a pin 14 on a body panel 16, an electric motor 18, and a coupling mechanism 20 connecting a motor output shaft 22 to the carrier 12. Head lamp 24
is mounted in the carrier 12, and the motor 18, when driven in a clockwise direction, moves the linkage 20 into engagement with the mechanical stop 26 to completely move the headlamp as shown by the solid line in FIG. be exposed. When motor 18 is driven counterclockwise as shown by arrow 28, coupling mechanism 20 is moved into engagement with mechanical mechanism 30, causing headlamp 24 to move as shown by the dotted line in FIG.
completely cover.

A headlamp switch, designated by the reference numeral 40, is mounted on the instrument panel 42 of the motor vehicle;
It is used by the driver of a car to turn on or blink the headlamp 24. The head lamp switch 40 includes a stem 44, a contact bar 46 which is a part thereof, and a pair of input contacts 48.
and 50, and a pair of output contacts 52 and 54. Input contacts 48 and 50 are electrically coupled at terminal 56, which is connected to the positive terminal of vehicle battery 60 via line 58. The negative terminal of storage battery 60 is connected to ground potential. Therefore, headlamp switch 4
When 0 is in the OFF position as shown in Figure 1,
Output contact 52 is opened and output contact 54 is connected to the positive terminal of battery 60 through contact bar 46 . When a driver pulls the headlamp switch stem 44 to turn on the vehicle's headlamps 24, the contact bar 46 disengages the input contact 50 and output contact 54 and engages the input contact 48 and output contact 52. Move to.
In this position, output contact 54 is open and connected to the positive terminal of battery 60 through output contact bar 46. Output contacts 52 and 54 of headlamp switch 40 are connected to input terminals 62 and 64 of a controller 66 which energizes motor 18 in response to predetermined voltages at its input terminals 62 and 64. is controlled to move the headlamp carrier 12 up and down.
For this purpose, lines 68 and 70 connect controller output terminals 72 and 74 to the input terminals of motor 18. Controller output terminals 76 and 78 are connected by similar devices to a second vehicle headlamp assembly (not shown). Control device 66
The power for
is obtained via a line 80 connecting the voltage to the positive terminal of the accumulator 60 as well as a line 82 connecting the control device 66 to ground potential. Controller input terminal 62 is connected to line 8 to energize headlamp 24 each time headlamp switch 40 is in the ON position.
4 to the terminal of the headlamp 24. The other terminals of the headlamp 24 are connected to the vehicle body panel 16 through a suitable device (not shown).
connected to ground potential at

FIG. 2 is a circuit diagram of the controller shown in FIG. 1, including controller input terminals 62 and 64, controller output terminals 72-78, and controller power connections and controller ground connections. For clarity of explanation, the controller 66 is functionally connected to the oscillator circuit 9
0, output circuit 92, starting circuit 94, input and reset circuit 96, stop detection circuit 98, and speed detection circuit 100. When activated, oscillator circuit 90 produces a series of output pulses for controlling the energization of motor 18. Output circuit 92 is responsive to the output pulses generated by oscillator circuit 90 and energizes motor 18 accordingly. Start circuit 94 operates each time motor 18 is started and generates a start pulse to energize motor 18 through output circuit 92 . Input and reset circuit 96 functions to properly operate oscillator circuit 90 and starting circuit 94 in response to operator operation of headlamp switch 40. The stall detection circuit 98 functions to interrupt energization of the motor when the headlamp carrier 12 moves relative to the mechanical stop 26 or 30 in response to the motor counter EMF related voltage. Speed detection circuit 1
00 also has the function of interrupting the energization of the motor when the rotational speed of the motor 18 exceeds the reference position in response to the motor counter EMF related voltage.

Oscillator circuit 90 is implemented by an integrated circuit motor 101, such as an ICM 7555 timer manufactured by Intersil Inc., Cupertino, California. In the illustrated embodiment, timer 101 operates as an oscillator, alternately charging or discharging capacitor 102. The charging circuit for capacitor 102 is the output (0) of capacitor 102 and timer 101.
a series-connected resistor 104 connected between
and a diode 106, and the discharge circuit also includes a series connected resistor 108 and a diode 110 connected between the output of the capacitor 102 and the OR gate 112. One input of OR gate 112 is connected via line 114 to the output (0) terminal of timer 101, thereby controlling its operation. When the output (0) terminal of motor 101 switches from its low state to its high state, capacitor 102 connects resistor 104 and diode 106.
The timer 101 is charged until the voltage therebetween exceeds a predetermined threshold value set inside the timer 101. When the threshold is exceeded, timer 101
(0) and thus the output of OR gate 112 changes from its high state to its low state, and cocapacitor 102 connects diode 110 and resistor 10
It is discharged through 8. When the voltage across capacitor 102 falls below a second threshold voltage generated internally in timer 101, the output (0) of timer 101 is switched back to its high output state and capacitor 102 is reactivated as described above. It will be charged. In this manner, oscillator circuit 90 provides a series of output signals on line 116, the frequency of which is determined by the combination of resistors 104 and 108 and the capacitor charge and discharge timer constants.

The foregoing operation is dependent on the voltage at the enable (EN) input of timer 101. When the activation input is held at a logic 1 potential, oscillator circuit 90 generates a series of output pulses as described above, while the activation input is held at a logic 0 potential.
Once held at potential, motor 101 is reset and the voltage on line 116 is held at a logic zero potential. As will be explained later, the voltage applied to the starting input of motor 101 is applied to input and reset circuit 9.
6. As also explained below, the second input of OR gate 112 is connected to speed detection circuit 100 to prevent capacitor 102 from discharging when a motor overspeed condition is detected.

The output circuit 92 includes a left motor drive circuit 120, a right motor drive circuit 122, and a motor reversing relay 12.
Contains 4. Left and right motor drive circuits 120 and 1
22 are AND gates 125, 126 connected to receive input signals from the oscillator circuit 90 via line 128 and from the stall detection circuit 98 via lines 130 and 132, respectively;
8 and the corresponding AND gate 12 via 140
5, 126 and starting circuit 9 via line 142
OR gate 13 for receiving input signals from 4
Contains 4,136. Left and right motor drive circuit 12
0 and 122 are also power transistors 144, 146 and corresponding OR gates 13, respectively.
4,136 and associated input resistors 148,150 connected between the motor reversing relay 124 and the motor reversing relay 124.
Power transistors 144, 146 control the energization of a headlamp control motor (eg, motor 18), and the conduction of power transistors 144, 146 is controlled by the output state of associated OR gates 134, 136. Left and right motor drive circuits 120 and 122 normally operate together in response to the output of oscillator circuit 90 or starting circuit 94, but when a motor stall condition is detected, line 13
A stop can also be made in place by a stop detection circuit 98 which operates to hold 0 and/or 132 at a logic 0 potential. power transistor 14
4 and 146 from inductive switching transients.
22 are the corresponding power transistors 14
4,146 includes a protection circuit consisting of series-connected diodes 152, 154 and Zener diodes 156, 158 connected between the gate and source circuits. When an inductive transient occurs, Zener diodes 156 and 158 conduct to keep power transistors 144 and 146 conductive.

Motor reversing relay 124 includes left and right bipolar dual-make switch mechanisms 160 and 162. The left and right switch mechanisms 160 and 162 include pairs of switch arms 164 and 166, 168 and 170, respectively, which can be selectively switched to one of two positions according to the energization of an electrical winding 172. . A spring or other resilient mechanism (not shown) typically holds the switch arms 164, 170 in the position shown in FIG.
with sufficient tension to move the contact downward into engagement with another contact. Power transistors 144 and 146 are connected to switch arm 1, respectively.
66 and 168, and is also connected to the automobile storage battery 6
0 to switch arm 164 via line 174
and 170. Regarding the motor 18,
Motor reversing relay 124 connects battery 60 to output terminal 72 and connects the drain of power transistor 146 to output terminal 74 in the position shown in FIG.
Connect to. Similarly, the storage battery 60 has an output terminal 78
and the drain of power transistor 144 is connected to output terminal 76 . In this condition, the motor DC, controlled through power transistor 146, produces counterclockwise rotation of motor 18 to lower headlamp carrier 12 to the fully covered position.

When electrical coil 172 is energized, switch arms 164-170 are switched to their opposite positions as described above. With respect to motor 18 , vehicle battery 60 is connected to output terminal 74 and the drain of power transistor 146 is connected to output terminal 72 . Similarly, battery 60 is connected to output terminal 76 and the drain of transistor 144 is connected to output terminal 78. In this condition, the motor current controlled through power transistor 146 produces clockwise rotation of motor 18, raising headlamp carrier 12 to the fully exposed position. Electrical coil 172 is connected to controller input terminal 62 through line 176 such that electric coil 172 is energized each time headlamp switch 40 is in the ON position and during the period that headlamp 24 is turned on.

Start circuit 94 includes a counter circuit 180 and a latch circuit 182. In the illustrated embodiment,
Counter circuit 180 may be an integrated circuit counter, such as a National Semiconductor counter.
CD4060 manufactured by Semiconductor Corporation), Santa Clara, California.
This can be realized with a 12-stage ripple-carrier binary counter. The output of oscillator circuit 90 is connected via line 116 to the clock C input of counter 184, which also produces output pulses on lines 186, 188 and 190 after a predetermined number of oscillator pulses have been counted. In the illustrated embodiment, one pulse is generated on line 186 after eight oscillator pulses have been counted, and 16
line 1 after oscillator pulses have been counted.
One pulse is generated on line 190 after 88 and 256 oscillator pulses have been counted.
One pulse is generated on the top. counter 184
When the reset input R of is raised to a logic 1 potential,
Output lines 186, 188 and 190 are set to zero.

The latch circuit 182 of the starting circuit 94
84 is operative to generate a starting pulse on line 142 to energize motor 18 at the beginning of motor operation. More specifically, latch circuit 182
is ANDed with a starting latch 192 consisting of an OR gate 194 and an AND gate 196 and an OR gate 200.
It includes a stop latch 198 consisting of a gate 202.
One input of OR gate 194 is connected to counter output line 186 and one input of OR gate 200 is connected to counter output line 188. AND gate 1 to provide latch operation.
96 is connected as an input to OR gate 194, and the output of AND gate 202 is connected to OR gate 2.
Connected as input to 00. OR gate 19
The output of 4 provides the input to AND gate 196;
The output of OR gate 200 provides an input to AND gate 202. AND gates 196 and 202
A separate input to is provided by input and reset circuit 96 through OR gate 218 and inverter 228 on line 204. line 204
is held at a logic one potential, output AND gate 196 latches at a logic one potential in response to an output pulse on counter output line 186, and
AND gate 202 output is counter output line 1
latches at a logic 1 potential in response to an output pulse on 88. The outputs of AND gates 196 and 202 are applied as inputs to exclusive OR gate 206, which outputs power transistors 144 and 1
46 is connected to line 142 to control conduction of 46.

Input and reset circuit 96 appropriately operates controlled oscillator circuit 90 and starting circuit 94 to provide the desired operation of headlamp carrier 12 in response to the voltages at controller input terminals 62 and 64. Controller input terminals 62 and 64 are exclusive ORed through input resistors 210 and 212 as inputs.
Connected to gate 214. exclusive OR gate 2
14 output is inverter 216 and OR gate 2
18 to the reset input R of the counter 184 and as an input to the AND gate 220 of the reset latch circuit designated by reference numeral 222. Reset latch circuit 222
further includes an OR gate 224 coupled across to AND gate 220. Output line 190 of counter 184 is applied as another input to OR gate 224. The output of OR gate 218 is connected to line 204 through inverter 228.

Controller input terminals 62 and 64 are typically held at approximately ground potential by electrical coil 172 and resistor 214. When the headlamp switch 40 is in its ON or OFF position, the
The output of OR gate 214 is held at a logic 1 potential. However, when headlamp switch 40 is shifted from one position to the other, exclusive
The output of OR gate 214 momentarily drops to a logic 0 potential, thereby driving the output of OR gate 218 to a logic 1 potential and the output of AND gate 220 to a logic 0 potential. As a result, counter 184 is reset and the output of AND gate 220 is held at a logic 0 potential. In addition to this, line 204 is driven to a logic zero potential and starting circuit 94
and disables oscillator circuit 90. When the headlamp 40 reaches its new position, the exclusive OR
The output of gate 214 returns to a logic one potential, thereby driving the output of OR gate 218 to a logic zero potential, and reset latch circuit 222 by driving one input of AND gate 220 to a logic one potential. Start. OR gate 224 is
The other input of AND gate 220 is held at a logic O potential, and line 204 is at its normal logic 1
potential, thereby activating the starter circuit 94 and oscillator circuit 90. Counter 184 is 256
After counting oscillator clock pulses, counter output line 190 is raised to a logic one potential, and the output of AND gate 220 is thereby latched at a logic one potential. as a result,
The output of OR gate 218 is raised to a logic one potential, which resets counter 184 and disables starter circuit 94 and oscillator circuit 90. This state is called the rest state and is maintained until the headlamp 40 is shifted to a new position.

The stop detection circuit 98 includes left and right detection circuits 230 and 231, each of which has a motor counter EMF.
Detecting a motor stop condition in response to an associated voltage. Right detection circuit 232 is responsive to counter EMF related voltages to motor 18 and is also responsive to left detection circuit 2
30 is responsive to a counter EMF to a headlamp operating motor, not shown in FIG. Each of circuits 230 and 232 includes a transistor 234, 236 connected to compare the voltage at the drain terminal of a corresponding power transistor 144, 146 to the battery voltage. The drain terminal of the power transistor terminal 144 is connected to the transistor 23
8 to the base input of transistor 234, and the drain terminal of power transistor 146 is connected to transistor 236 through resistor 240.
connected to the base input of The emitter inputs of both transistors 234 and 236 are connected to the starting circuit 94.
The stall detection circuit performs the voltage comparison only after the starting circuit 96 generates a starting pulse to start the motor. The collector of transistor 234 is connected as an input to AND gate 124 of left motor drive circuit 120, and the collector of transistor 236 is connected as an input of AND gate 126 of right motor drive circuit 122. The resistor 250 is usually
The input of AND gate 124 is held at ground potential,
Resistor 252 also typically holds this input of AND gate 126 at ground potential. While the headlamp carrier motor is operating, transistor 2
34 and 236 are biased conductive, thereby allowing AND gates 124 and 126 to pass the oscillator output signal applied thereto via line 128. However, the headlamp operating mechanism 1
When the zero linkage 20 engages the stop 26 or 30, the motor 18 stops and the motor counter EMF drops to approximately zero. As soon as the corresponding power transistor 144, 146 is biased to its non-conducting state, the voltage at its drain rises to approximately the battery voltage. At this point, transistors 234 and/or 23
6 becomes non-conducting and AND gates 124 and/or 126 interrupt further oscillator output pulses on line 128, thereby interrupting further energization of the motor.

The speed detection circuit 100 includes a power transistor 14
6 at the drain terminal of line 260 and resistors 262 and 264.
is connected to the base terminal of transistor 266 via. The positive terminal of battery 60 connects junction 26 between resistors 262 and 264 to measure the magnitude of the voltage sensed across resistor 268.
Connected to 9. Furthermore, a voltage divider consisting of resistors 270, 272 and 274 connected in series and a Zener diode 276 is connected between the positive terminal of storage battery 60 and ground potential for the purpose of generating a reference voltage with which the detected voltage is compared. . The reference voltage is the junction 278 between resistors 270 and 272.
, which corresponds to a motor speed that must not be exceeded. The collector of transistor 266 is connected as an input to AND gate 280;
It is also connected to the output of the OR gate 218 via a resistor 284. Another input to AND gate 280 is AND gate 202 of starting circuit 94.
obtained from the output of The output of AND gate 280 is connected to oscillator circuit 9 via line 282 as an input.
0 OR gate 112.

When the speed of motor 18 falls below the reference speed and transistor 146 becomes non-conducting, transistor 266 remains non-conducting and resistor 284 holds the collector of transistor 266 at a logic zero potential. As a result, the output of AND gate 280 is also held at a logic zero potential and the discharge of capacitor 102 is not interrupted. However, when the motor speed increases above the reference speed,
Motor counter EMF is power transistor 14
holding the voltage at the drain of 6 low enough to bias transistor 266 into a conducting state;
This raises the voltage at its collector to a logic one potential. The output of AND gate 202 is logic 1
Once the potential is reached (i.e., once the motor start pulse is complete), the output of AND gate 280 is also a logic one.
By this, the OR of the oscillator circuit 90 is
The output of gate 112 is held at a logic one potential, interrupting operation of oscillator circuit 90, and capacitor 10
2. Prevents discharge. As a result, when the motor speed falls below the reference speed, transistor 266 returns to its non-conducting state and the output of OR gate 112 is again dominated by the logic level at the output (0) of timer 101. In this state, oscillator circuit 90 resumes producing output pulses for output circuit 92 on line 128.

A fail-safe circuit, designated by the reference numeral 290, monitors the motor drive status and the status of the headlamp switch 40, and
When motor 18 is energized to lower headlamp 20 when headlamp 0 is not in the OFF position, it operates to reset latch 222 of input and reset circuit 96. Fail-safe circuit 290 includes a three-input OR gate 292 whose output is connected to latch 222 as an input through inverter 294.
is added to the OR gate 224 of OR gate 2
The first input to 92 is headlamp switch 40.
and also line 296 and resistor 2
12 to a control device input terminal 64. When headlamp switch 40 is in the OFF position, this input is at a logic 1 potential, and when headlamp switch 40 is in the ON position, this input is at a logic 0 potential. A second input to OR gate 292 is responsive to the drive state of motor 18;
and through line 300 the control device output terminal 7.
Connected to 4. A pull-up resistor 302 connects line 300 to the positive terminal of battery 60. With motor reversing relay 124 in the position shown in FIG. 1 and power transistor 146 biased in its conductive state, motor 18 is driven in a direction that lowers headlamp carrier 12. In this state, the second input to OR gate 292 is driven from its normal logic 1 potential to a logic 0 potential.
Therefore, the second input to OR gate 292 will be at a logic one potential at all times except when motor 18 is driven in a direction that lowers headlamp carrier 12. A third input to OR gate 292 detects the output state of right motor drive circuit 122 and is also connected to the output of OR gate 136 via line 304 and inverter 306. OR
The output of the gate 136 is the power transistor 146
This input becomes a logic 0 potential when driven to a logic 1 potential to drive it into its conductive state. Otherwise, this input is at a logic 1 potential. Headlamp switch 40 is not in the OFF position and is in the OR position.
When gate 136 is driven to a logic one potential to bias power transistor 146 to its conducting state, the output of OR gate 292 falls to a logic zero potential. The output of inverter 294 then rises to a logic one potential, thereby setting latch 222 of input and reset circuit 96. As a result, the outputs of AND gate 220 and OR gate 218 rise to a logic one potential, thereby resetting counter 184 and disabling timer 101. Failsafe circuit 290 thus prevents controller 66 from energizing motor 18 in a direction that lowers headlamp carrier 12 unless headlamp switch 40 is in the OFF position.

The operation of the control device of the present invention will be explained with reference to FIGS. 1 and 2. In the sleep or reset condition, headlamp switch 40 is in the OFF position, holding controller input terminal 64 at a logic one potential and opening controller input terminal 62 to de-energize headlamp 24. Within controller 66, exclusive OR gate 214 is held at a logic one potential and latch circuit 222 of input reset circuit 96 is held in a set position. As a result, the output of OR gate 218 is held at a logic one potential, resetting counter 184 and disabling starting circuit 94 and timer 101. Electric coil 172 of motor reversing relay 124 is deenergized and relay contact arms 164-170 are
It is held in the position shown in the figure.

When the vehicle operator shifts the headlamp switch 40 to the ON position to turn on the vehicle headlamp 24, the controller input terminal 64 is opened and the input terminal 62 is connected via line 84 to energize the headlamp 24. is connected to the positive terminal of the storage battery 60. At the same time, the electric coil 172 of the motor reversing relay 124
64-170 are biased to a position opposite to that shown in FIG. In addition, the output of exclusive OR gate 214 is temporarily pulled to a logic zero potential, thereby temporarily resetting counter 184. At the end of this reset, timer 101 begins producing output pulses on line 116 and counter 184 counts the pulses. Once eight such pulses have been counted, counter 184 will
6, which sets the start latch 192 of the start circuit 198. As a result, line 142 rises to a logic one potential, causing power transistors 144 and 146 to OR gate 13.
4 and 136 to the conductive state, energizing the headlamp motor 18. Due to the energization of the relay electric coil 172, this motor energization produces motor rotation in the direction of raising the headlamp carrier 12. When 16 timer output pulses have been counted by counter 184, line 1
An output pulse is generated on 88 which sets stop latch 198 of starting circuit 94. At this point, the output of exclusive OR gate 206 drops to a logic zero potential and power transistor 1
44 and 146 are biased to their non-conducting state to de-energize motor 18. In the preferred embodiment, timer 101 produces output pulses on line 116 at a rate of approximately 60 Hz. Therefore, the output pulse on line 186 of counter 184 occurs approximately 170 milliseconds after the temporary reset caused by shifting headlamp switch 40 to the ON position. Thus, the counter 184 inserts a delay between shifting the headlamp switch 40 to the ON position and energizing the headlamp motor 18, which delay is caused by the electrical coil 172 of the motor reversing relay 124 passing through the relay contact arms 164-170. 2 to the opposite position as shown in FIG. Similarly,
Counter 184 inserts a delay of approximately 170 milliseconds between the generation of the output pulse on line 186 and the output pulse on line 188. As a result, starting circuit 94 energizes motor 18 through OR gates 134 and 136 for a period of approximately 170 milliseconds, which provides motor rotation to increase motor counter EMF substantially above zero. This is a sufficient period of time. Thus, transistors 234 and 236 of left and right stall detection circuits 230 and 232 remain conductive after the motor start pulse has terminated, and motor energization remains on line 12.
It is activated according to the output pulse of timer 101 on 8. This output pulse coordinately biases power transistors 144 and 146 through AND gates 124 and 126, OR gates 134 and 136, and resistors 148 and 50 to conductive and nonconductive states. During this operation, the speed of motor 18 is typically forced below a reference speed defined by the voltage divider of speed detection circuit 100, such that transistor 266 is in a non-conducting state when motor 18 is not energized. Ru. If the rotational speed of motor 18 creates a motor counter EMF such that the sensed voltage on line 260 exceeds the reference while headlamp carrier 12 is being raised, transistor 266 remains conductive and AND gate 280 The output of oscillator circuit 90 is held at a logic one potential to prevent capacitor 102 of oscillator circuit 90 from discharging. This action interrupts the energization of the motor 18 and energization is inhibited until the rotational speed of the motor falls below its speed reference. Such overspeed conditions can be caused, for example, by abnormally high system operating voltages.

With the mechanism of the present invention, the raising of the vehicle headlamp 24 takes approximately 0.6 seconds. When the headlamp is raised to its normal position, coupling member 20 engages fixed mechanical stop 26, thereby stopping carrier 12 and stopping motor 18.
At this point, the motor counter EMF drops rapidly to approximately zero, and transistors 234 and 232 of left and right stall detection circuit 230 become non-conducting each time motor 18 is deenergized. At this point, lines 130 and 132 fall to a logic zero potential, inhibiting the motor from being energized through AND gates 124 and 126. The left and right stop detection circuits 230 and 232 operate independently of each other and are connected to each headlamp drive motor 1.
8 is stopped at the appropriate time. Timer 101 continues to generate output pulses, but these pulses have no effect on energizing headlamp motor 18.
Counter 184 is approximately 4 on line 190 following a shift of headlamp switch 40 to the ON position.
It generates a second output pulse which stops this drive by setting the latch circuit 222 of the input and reset circuit 96. As a result, AND gate 220 and OR gate 21
8 rises to a logic 1 potential, and the counter 184
and also resets the starting circuit 94 and timer 10.
disable 1. The period of time shutdown thus provided is independent of the shutdown detection circuits 230 and 232, and thus serves to interrupt energization of the motor if the motor 18 is disconnected from the headlamp carrier 12. This condition continues until headlamp switch 40 is shifted to the opposite position to lower the vehicle headlamps.

The driver of the car turns on the headlamp switch 40.
When the headlamp 24 is deenergized by shifting from the ON position to the OFF position, the controller input terminal 64 is connected to the positive terminal of the battery 60 and the controller input terminal 62 is opened to deenergize the headlamp 24. . At this point, motor reversing relay 1
24 electrical coils 172 are deenergized and relay contact arms 164-170 return to the position shown in FIG. motor rotation will be generated. With the exception of the motor reversing relay operation described above, the operation of the controller 66 to lower the headlamp carrier 12 is similar to the operation described above with respect to raising the headlamp carrier 12. That is, exclusive
OR gate 214 temporarily resets counter 184, and after a sufficient time delay for relay contact arms 164-170 of motor reversing relay 124 to assume their new positions, counter 184 causes motor rotation. provides start and stop pulses to the start circuit 94 of the. The 170 millisecond period of operation of starting circuit 94 is sufficient to provide a motor counter EMF to bias transistors 234 and 236 of left and right stall detection circuits 230 and 232 to their transmission states, and thereafter The motor is energized by line 1.
It is controlled according to the output pulse of timer 101 on 28. After that, the motor speed is determined by the speed detection circuit 10.
Once the speed reference set by zero is exceeded, transistor 266 is biased to its conductive state, interrupting the production of further output pulses from timer 101. When the headlamp is completely covered, motor link 20 engages fixed mechanical stop 30 and motor 18 is stopped. At this point, the motor counter EMF is essentially 0.
and transistors 234 and 236
becomes non-conducting, thereby inhibiting further energization of the motor through AND gates 124 and 126. Then, after a short period of time, counter 184 produces an output on line 190 to close latch 222 of reset and latch circuit 96.
is set to reset counter 184 and also disable starter circuit 94 and oscillator circuit 90.

In the manner described above, the control system of the present invention controls the raising and lowering of the headlamp carrier 12 and its engagement with the mechanical stops 26, 30 without the use of position or torque limit switches. To detect. Most of the controller circuitry shown in FIG. 2 can be implemented with a single conventional integrated circuit, thereby reducing manufacturing costs and power consumption. Although the invention has been described in the context of a system with a movable headlamp, it is equally applicable to systems with one fixed headlamp and a movable headlamp cover. These and other modifications are possible to those skilled in the art, and systems incorporating these modified embodiments are also within the scope of the invention as defined by the appended claims.

[Brief explanation of drawings]

1 is a simplified diagram showing the headlamp mechanism and control device of the present invention; and FIG. 2 is a circuit diagram of the control device shown in FIG. 1.

Claims (1)

[Scope of Claims] 1 An automobile lighting device comprising: a headlamp; a headlamp switch operated by the driver; a movable storage means; a DC voltage source; connected to the storage means and powered by the voltage source. an electric motor operated to engage the retraction means with a mechanical stop to fully expose the headlamp; and motor control means, the motor control means being responsive to operator operation of the headlamp switch. oscillator means for generating pulses of; and in response to the pulses generated by the oscillator means, for energizing the motor with the voltage source to move the storage means toward the mechanical stop. a running means; detecting a motor counter EMF-related voltage to determine whether the motor is rotating; and when the motor counter EMF falls to approximately 0, it is determined that the speed of the motor has fallen to approximately 0; voltage response means for outputting a stop signal indicating the stop signal to detect engagement between the storage means and the stop without using a limit switch; a stop means for responsively inhibiting further movement of the travel means and interrupting energization of the motor after the motor has moved the storage means into engagement with the mechanical stop; In response to operator operation of a switch, the motor is turned on independently of the traveling device for a period of time sufficient to provide motor rotation to increase the motor counter EMF to substantially zero or more. and starting means for controlling the energization of the motor by the running means, the voltage responsive means and the stopping means, the motor control means controlling the operation of the running means by controlling the operation of the headlamp switch. A vehicle lighting system including means for preventing continued energization of the motor when the motor is disconnected from the storage means by inhibiting for a predetermined period of time after operation by a driver. 2. In a motor vehicle lighting system, movable storage means for a headlamp; a DC voltage source; energized by the voltage source to move the movable storage means into engagement with a first or second mechanical stop; an electric motor for completely exposing or covering the headlamp; energizing the headlamp when turned on by the driver;
It also includes a headlamp switch operable to de-energize the headlamp by turning it to the OFF position; and a motor control means that outputs a series of pulses in response to operator operation of the headlamp switch. oscillator means for generating; energizing the motor with the voltage source in response to pulses generated by the oscillator means to activate the storage means when the headlamp switch is in the ON position; move toward the first mechanical stop to expose the headlamp, and the headlamp switch is
a motor counter for moving towards a second mechanical stop when in the OFF position;
Detects EMF-related voltage to determine whether the motor is rotating, and when the motor counter EMF falls to approximately 0, outputs a stop signal indicating that the speed of the motor has fallen to approximately 0. , voltage response means capable of detecting engagement between the storage means and the stop without using a limit switch; and a voltage response means capable of detecting engagement between the storage means and the stop; a stop means for inhibiting further operation and interrupting energization of the motor after the motor has moved the storage means into engagement with the mechanical stop; In response, the motor is energized for a period of time independent of the travel means sufficient to provide motor rotation to increase the motor counter EMF to substantially zero or more; starting means whose energization is controlled by said running means, said voltage responsive device and said stopping device; when said headlamp switch is in the ON position said motor causes said second mechanical stop to retract said headlamp; and means for interrupting energization of the motor to prevent further movement of the storage means when the storage means is energized to move the storage means towards. 3. A headlamp switch operated by the driver, a movable carrier for the headlamp, a DC voltage source and energized by the voltage source connected to the carrier to move the carrier in the direction of engagement with a mechanical stop. A method of operating a vehicle lighting system including an electric motor for fully exposing the headlamp by: activating the motor in response to operation by a driver of the headlamp switch to fully expose the headlamp; moving said carrier toward said machine stop by energizing for a predetermined period sufficient to provide motor rotation to increase the EMF substantially above zero; and thereafter said headlamp. Continuing to energize the motor with a series of pulses to further move the carrier: Detecting the motor counter EMF related voltage to determine if the motor is rotating;
using a limit switch to detect engagement of the carrier with the stop by outputting a stop signal indicating that the motor speed has fallen to substantially zero when the EMF has fallen to substantially zero; Detecting engagement without interruption: interrupting energization of the motor in response to the output of a stop signal, thereby ensuring that the motor is further energized after the carrier has engaged with the mechanical stop. and continuing energization of the motor when the motor is disconnected from the headlamp carrier by deenergizing the motor for a predetermined period following operation of the headlamp switch by the operator. A method of operation comprising the step of: 4. A movable carrier for the headlamp, a direct current voltage source, energized by the voltage source to move the carrier to a first
or an electric motor for completely exposing or covering the headlamp by moving it in a direction that engages with a second mechanical stop, and energizing the headlamp by turning it into the ON position or turning it OFF by operation of the driver. A method of operating a motor vehicle lighting system including a headlamp switch capable of deenergizing the headlamp by: activating the motor in response to operator operation of the headlamp switch. When the headlamp switch is in the ON position, the carrier is energized for a predetermined period sufficient to provide motor rotation to increase the motor counter EMF substantially above zero. exposing the headlamp by moving it towards a stop, and covering the headlamp by moving it towards a second mechanical stop when the headlamp switch is in the OFF position:
and thereafter continuing to energize the motor with a series of pulses to further move the headlamp carrier; detecting a motor counter EMF related voltage to determine whether the motor is rotating; a headlamp switch for detecting engagement of the carrier with the stop by outputting a stop signal indicating that the motor speed has fallen to substantially zero when the counter EMF has fallen to substantially zero; detecting the engagement without use; interrupting energization of the motor in response to outputting a stop signal, thereby further energizing the motor after the carrier has engaged the mechanical stop; and the headlamp switch is in the ON position and the motor is energized to move the headlamp carrier toward the second mechanical stop to cover the headlamp. 2. A method of operation comprising the step of: interrupting energization of the motor to prevent further movement of the headlamp carrier.