JP2994403B2 - Drive control device for electric folding rearview mirror - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive control device for automatically stopping a housing of a vehicle electric retractable rearview mirror at a retracted or used position.

(Prior Art) Conventionally, as a device for rotating a housing of a vehicle electric retractable rearview mirror by driving a motor and storing or stopping it at a use position, a drive unit housed in a housing or the like has a drive unit mounted on a vehicle body side. There is known a device in which a mechanical switch such as a limit switch is arranged between a fixed supporting member and a movable member on the housing side to cut off power supply to a motor.

In addition, there has been known an apparatus in which a change in load current of a motor is detected in place of the limit switch or the like to cut off power supply to the motor (for example, Japanese Patent Application Laid-Open No. SHO 61-110938).
Reference).

(Problems to be Solved by the Invention) In the former among those described in the prior art, in the drive unit, in addition to a motor as a drive source and a reduction gear, parts such as a limit switch must be housed in a housing. In addition, there is a problem that the shape of the housing is restricted and it is difficult to make the housing compact, and that a high switch accuracy and an assembling accuracy are required to correctly set the stop position.

Further, the latter has a problem that the load of the motor is different due to the variation of the motor and the reduction gear, and it is necessary to consider a change with time, and it is not easy to determine the reference value of the load current. Was.

The present invention has been made in view of the above-described problems of the related art, and an object of the present invention is to detect a change in the number of rotations of a motor and input a power supply cutoff command to a motor drive circuit. Therefore, it is an object of the present invention to provide a compact and stable drive control device for an electric retractable rearview mirror that does not require a limit switch by stopping the motor.

(Means for Solving the Problems) In order to solve the above problems, the present invention is directed to a mirror housing which is used in a storage position with respect to a support member fixed to a vehicle body by rotating a motor disposed in a mirror housing in a normal or reverse direction. A change in the number of rotations of a driving member by a rotation restricting member that restricts a rotation range provided between the support member and the housing is detected in an electric folding rearview mirror that is mounted so as to be rotatable between the position and the position. A motor stop command circuit for comparing the output value of the rotation detector with a preset reference value and outputting a power supply cutoff command to the motor drive circuit.

(Operation) In the present invention configured as described above, the increase or decrease in the load applied to the motor by the rotation restricting member causes a change in the rotation speed of the drive member, and the change is detected by the motor rotation detector, and A comparison is made with the set reference value, a power supply cutoff command is output to the motor drive circuit, and the housing is stopped at the storage position or the use position.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partially cutaway front view of an electric retractable rearview mirror provided with a drive control device according to the present invention, FIG. 2 is an exploded view of a support member and the like, and FIG. FIG.

As shown in FIG. 1, the electric retractable rearview mirror is configured such that a motor 2 disposed in a mirror housing 1 is rotated forward and backward to form a cylindrical member with a base member 3 fixed to the vehicle body via a reduction gear group G. The mirror housing 1 is attached to a supporting member 5 integrally formed with the fixed shaft 4 so that the mirror housing 1 can be rotated between the storage position and the use position by driving the motor 2.

Further, an iron piece 2b is fixed near the outer periphery of the side surface of the worm wheel G2 meshing with the worm G1 fixed to the output shaft 2a of the motor 2 in order to detect the rotation speed of the driving member.
The rotation detector S is provided at a position facing the rotation detector S. The rotation detector S is a magnetic sensor that detects a moving magnetic body such as iron or the like in a non-contact manner and outputs a pulse signal. Incidentally, a plurality of iron pieces 2b may be provided at equal intervals so as to pass under the rotation detector S. Further, a pulse generator or the like may be directly attached to the output shaft 2a of the motor 2 as the rotation detector S.

Further, between the support member 5 and the mirror housing 1, a rotation restricting member 6 for restricting the rotation range of the mirror housing 1 is formed.

The rotation restricting member 6 is, as shown in FIG.
A plurality of first concave portions formed radially on the upper surface of the central step portion 3a
3b, a second recess 3c formed between the first recesses 3b, and a plurality of engagement holes 7b formed on the lower surface of a base 7a of a bracket 7 rotatably fitted on the fixed shaft 4. It consists of a ball 8.

Some of these steel balls 8 protrude downward from the engagement holes 7b to form convex portions, and the protruding portions correspond to the first concave portions 3b or the second concave portions 3b.
It engages with the recess 3c. Further, since the bracket base 7a is pressed downward by the spring 9, it is engaged with a predetermined pressure. Therefore, in a normal state, the position of the bracket 7 is held with respect to the base member 3.

As shown in FIG. 3, the position where the first concave portion 3b and the steel ball 8 are engaged is the position where the mirror housing 1 is used, and the second concave portion 3c and the steel ball 8 are engaged. The position is the storage position of the mirror housing 1.

Therefore, when the mirror housing 1 moves from the use position to the storage position, the steel ball 8 separates from the first recess 3b against the elasticity of the spring 9, and slides on the upper surface of the drive collapsible sliding surface 3d, It engages with the two concave portions 3c, and its position is maintained. Conversely, when the mirror housing 1 moves from the storage position to the use position, the steel ball 8 separates from the second concave portion 3c and slides on the drive collapsible sliding surface 3d to engage with the first concave portion 3b.

When the mirror housing 1 is rotated by the motor 2 from the use position to the storage position or from the storage position to the use position to be positioned at that position, the steel ball 8 is moved to the first position.
The motor 2 is stopped by detecting a change in the number of rotations of the driving member when engaging with the concave portion 3b or the second concave portion 3c.

FIG. 4 shows a case where the rotation number of the worm wheel G2, which is a driving member driven by a motor driving circuit 22 composed of a constant voltage power supply circuit 20 and a motor control circuit 21, is detected by a rotation detector S, and a predetermined reference value is set. 4 shows a drive control device provided with a motor stop command circuit 23 that outputs a power supply cutoff command to the motor drive circuit 2 when a predetermined number of revolutions is reached.

The output signal of the rotation detector S is input to the counting and comparing circuit 28 via the waveform shaping circuit 25, the amplitude limiting circuit 26, and the gate circuit 27 of the amplifier circuit 24. On the other hand, crystal oscillation circuit 29, frequency divider 3
0, the reference value created by the gate control circuit 31 is also input to the count comparison circuit 28. Then, the frequency of the output signal of the rotation detector S and the frequency of the reference value are compared, and the steel ball 8 is engaged with the first or second concave portion 3b, 3c, and the frequency of the reference value and the output of the rotation detector S are output. When the difference from the frequency of the signal falls within a predetermined range, the count comparison circuit 28 inputs a power supply cutoff command to the constant voltage power supply circuit 20 via the prohibition circuit 32, and stops the motor 2. The prohibition circuit 32 is a circuit for cutting the output signal of the rotation detector S when the motor 2 starts. 33 is a start switch, and 34 is a battery.

FIG. 5 is a diagram showing a configuration of a reference value based on an output signal generated at the rotation detector S during driving in a steady state except when the motor 2 is started, instead of the crystal oscillation circuit 29 for generating the reference frequency shown in FIG. 1 shows a drive control device provided with a motor stop command circuit 35 for creating a frequency.

In order to create a reference frequency, the output of the amplitude limiting circuit 26 is input to the oscillation circuit 37 via the photocoupler 36. on the other hand,
The output signal of the rotation detector S, which is compared with the reference frequency, is input to the count comparison circuit 28 via the delay circuit 38, the gate circuit 27, and the gate circuit 27 in order to secure the time required for generating the reference frequency. When the steel ball 8 is engaged with the first or second concave portion 3b, 3c and the frequency of the output signal of the rotation detector S becomes lower than the reference frequency by a predetermined value, the power supply cutoff command is inhibited.
The signal is input to the constant voltage power supply circuit 20 via 32 and the motor 2 is stopped.

(Effects of the Invention) As described above, according to the present invention, it is possible to reduce the size of the electric retractable rearview mirror without requiring a mechanical limit switch or the like for interrupting power supply to the motor.

Further, a stable stopping operation at the storage position or the use position of the mirror housing can be ensured without being affected by environmental conditions such as a temperature change.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an electric retractable rearview mirror having a drive control device according to the present invention, FIG. 2 is an exploded view of a support member and the like, and FIG. FIG. 4, FIG. 4 and FIG. 5 are block diagrams of the drive control device. In the drawings, 1 is a mirror housing, 2 is a motor, 5 is a support member, 6 is a rotation restricting member, 22 is a motor drive circuit, 2
Reference numerals 3 and 35 are motor stop command circuits.

Claims (1)

(57) [Claims] An electric motor mounted on a support member fixed to a vehicle body by rotating a motor disposed in a mirror housing in a normal or reverse direction so that the mirror housing can rotate between a storage position and a use position. In the inverted rearview mirror, a rotation detector that detects a change in the number of rotations of a driving member by a rotation restricting member that restricts a rotation range provided between the support member and the housing, and an output value of the rotation detector and A drive control device for an electric retractable rearview mirror, comprising a motor stop command circuit for comparing a set reference value and outputting a power supply cutoff command to a motor drive circuit.