Vehicular mirror angle controller

• US 6,841,960 B2
• Filed: 04/10/2003
• Issued: 01/11/2005
• Est. Priority Date: 04/19/2002
• Status: Expired due to Fees

• Current Assignee: Murakami Corporation
• Original Assignee: Murakami Corporation
• Inventors: Nagao, Mituyoshi, Sato, Hidenori, Yamada, Ayako
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US10/410,233
• Publication Number:
  US 20030214738A1
• Time in Patent Office: 642 Days
• Field of Search: 318/445, 318/446, 318/466, 318/468, 359/874, 359/876, 359/877, 250/206
• US Class Current: 318/468
• CPC Class Codes: B60R 1/07 by electrically powered actuators

Abstract

In response to an operation of reversing a vehicle, a tilt motor is rotated by a specific amount in a normal direction to tilt a mirror angle to a position that permits a mirror to provide the driver with a view of the area near a rear wheel of the vehicle, while in response to an operation of releasing the reverse gear, the tilt motor is rotated by a specific amount in a reverse direction to restore the tilt angle to a normal position thereof. During the operations, a high-frequency signal generated upon switching a brush of the motor is detected using a pickup coil to determine an amount of rotation of the motor. One and the same pickup coil may be used for detection during both of normal and reverse rotations. A voltage of a battery 3 is stabilized in a motor power stabilizing circuit 10, and supplied via a motor driving circuit 8 to a tilt motor M2. Polarity of the voltage outputted from the motor power stabilizing circuit 10 is fixed. Polarity of the voltage outputted from the motor driving circuit 8 is switchable according to a switching operation of the motor driving circuit 8 based upon a driving direction instruction. The pickup coil L10 is provided between the motor power stabilizing circuit 10 and the motor driving circuit 8.

Claims

1. A vehicular mirror angle controller comprising:

a tilt motor comprised of a direct current brush motor that adjusts a mirror angle;

a motor driving circuit that drives the tilt motor to rotate;

a feed line for the tilt motor that provides connection from a direct current power supply via the motor driving circuit to the tilt motor; and

a pickup coil provided in the feed line between the direct current power supply and the motor driving circuit to detect a high-frequency signal that is generated when a brush is switched during rotation of the tilt motor,

wherein if an instruction is given to rotate the tilt motor by a specified amount in one of two opposite directions, the controller drives the tilt motor to rotate in the instructed direction, and controls an operation of the tilt motor according to an actual rotation amount of the tilt motor determined based upon the high-frequency signal detected by the pickup coil;

wherein polarity between the direct current power supply and the motor driving circuit is fixed, while polarity between the motor driving circuit and the tilt motor is switched according to a switching operation of the motor driving circuit based upon a driving direction instruction; and

wherein one and the same pickup coil is used to detect the high-frequency signal on both occasions where the tilt motor is rotated in one of the opposite directions and where the tilt motor is rotated in the other of the opposite directions.

5. A vehicular mirror angle controller according to claim 1, wherein the direct current power supply includes a battery and a motor power stabilizing circuit that stabilizes an output voltage of the battery to supply the stabilized voltage to the motor driving circuit;

and

wherein the pickup coil is provided between the motor power stabilizing circuit and the motor driving circuit.

2. A vehicular mirror angle controller comprising:

a tilt motor comprised of a direct current brush motor to which a power supply voltage is manually applied to drive the tilt motor to rotate, so as to make a mirror angle adjustable, the tilt motor being controlled to normally rotate to tilt a mirror to a desired set position in response to a supply of an external signal, while being controlled to reversely rotate to return the mirror to a normal position in response to suspension of the supply of the external signal;

a motor driving circuit that drives the tilt motor to rotate;

a feed line for the tilt motor that provides connection from a direct current power supply via the motor driving circuit to the tilt motor;

a pickup coil provided in the feed line between the direct current power supply and the motor driving circuit to detect a high-frequency signal that is generated when a brush is switched during rotation of the tilt motor;

a pulse counter that counts the number of pulses in the high-frequency signal detected by the pickup coil; and

a rotation angle correcting means that detects as an excess count value the number of pulses in the high-frequency signal corresponding to extra rotation of the tilt motor coasting beyond the set position when the tilt motor is normally rotated to adjust the mirror angle to the set position and beyond the normal position when the tilt motor is reversely rotated to adjust the mirror angle to the normal position, and based upon the detected excess count value corrects a rotation amount of the mirror to be rotated next time when the tilt motor is reversely rotated to adjust the mirror angle to the normal position and when the tilt motor is normally rotated to adjust the mirror angle to the set position,

wherein polarity between the direct current power supply and the motor driving circuit is fixed, while polarity between the motor driving circuit and the tilt motor is switched according to a switching operation of the motor driving circuit based upon a driving direction instruction; and

wherein one and the same pickup coil is used to detect the high-frequency signal on both occasions where the tilt motor is normally rotated and where the tilt motor is reversely rotated.

4. A vehicular mirror angle controller according to any one of claims 2 and 3, further comprising:

a waveform-shaping means that shapes a waveform of the high-frequency signal detected by the pickup coil so as to generate a rectangular wave as a unit corresponding to one switching operation of a brush; and

a rectangular wave generating means that generates another rectangular wave which is turned on and kept for a specific period in synchronization with timing of generation of the rectangular wave as a unit,

wherein the pulse counter counts the number of pulses in a pulse signal obtained through a logic operation of an output signal from the waveform-shaping means and an output signal from the rectangular wave generating means.

6. A vehicular mirror angle controller according to claim 2, wherein the direct current power supply includes a battery and a motor power stabilizing circuit that stabilizes an output voltage of the battery to supply the stabilized voltage to the motor driving circuit;

and

wherein the pickup coil is provided between the motor power stabilizing circuit and the motor driving circuit.

8. A vehicular mirror angle controller according to claim 4, wherein the direct current power supply includes a battery and a motor power stabilizing circuit that stabilizes an output voltage of the battery to supply the stabilized voltage to the motor driving circuit;

and

wherein the pickup coil is provided between the motor power stabilizing circuit and the motor driving circuit.

3. A vehicular mirror angle controller comprising:

a tilt motor comprised of a direct current brush motor to which a power supply voltage is manually applied to drive the tilt motor to rotate, so as to make a mirror angle adjustable, the tilt motor being controlled to normally rotate to tilt a mirror to a desired set position in response to a supply of an external signal, while being controlled to reversely rotate to return the mirror to a normal position in response to suspension of the supply of the external signal;

a motor driving circuit that drives the tilt motor to rotate in one of normal and reverse directions based upon a motor drive control signal;

a feed line for the tilt motor that provides connection from a direct current power supply via the motor driving circuit to the tilt motor;

a pickup coil provided in the feed line between the direct current power supply and the motor driving circuit to detect a high-frequency signal that is generated when a brush is switched during rotation of the tilt motor;

a pulse counter that counts the number of pulses in the high-frequency signal detected by the pickup coil;

a reference count value setting means that sets as a reference count value the number of pulses in the high-frequency signal counted by the pulse counter when the tilt motor is normally rotated to adjust the mirror angle to the set position and when the tilt motor is reversely rotated to adjust the mirror angle to the normal position;

an excess count value storing means that stores as an excess count value the number of pulses in the high-frequency signal corresponding to extra rotation of the tilt motor coasting beyond the set position when the tilt motor is normally rotated to adjust the mirror angle to the set position and beyond the normal position when the tilt motor is reversely rotated to adjust the mirror angle to the normal position; and

a motor drive controller that outputs a motor drive control signal instructing the tilt motor to rotate next time reversely to adjust the mirror angle to the normal position and normally to adjust the mirror angle to the set position by such a rotation amount that the number of pulses in the high-frequency signal to be generated when the tilt motor is rotated becomes the number of pulses obtained by adding the excess count value to the reference count value,

wherein polarity between the direct current power supply and the motor driving circuit is fixed, while polarity between the motor driving circuit and the tilt motor is switched according to a switching operation of the motor driving circuit based upon a driving direction instruction; and

wherein one and the same pickup coil is used to detect the high-frequency signal on both occasions where the tilt motor is normally rotated and where the tilt motor is reversely rotated.

7. A vehicular mirror angle controller according to claim 3, wherein the direct current power supply includes a battery and a motor power stabilizing circuit that stabilizes an output voltage of the battery to supply the stabilized voltage to the motor driving circuit;

and

wherein the pickup coil is provided between the motor power stabilizing circuit and the motor driving circuit.