JPH068094B2 - Control device for automobile electric mirror - Google Patents

Description

Description: [Object of the invention] (Field of industrial application) The present invention relates to a control device for an electric mirror for an automobile, in which a mirror surface is rotated by a motor.

(Prior Art) For example, a remote control door mirror of an automobile has a limited view due to a reflected image on the mirror surface, so that when the automobile is put in the garage and when the vehicle is moved close to the garage or the driver takes turns, the seat is seated. When the position is changed, the mirror surface is rotated from the passenger compartment to a desired position. When the mirror surface is rotated in this way, it is necessary to return the mirror surface to the original position when the garage entry is completed after that or when the original driver is replaced again.
Actually, there is a problem that the operation itself for returning the mirror surface to the original position becomes complicated. For this reason, in recent years, the normal position of the mirror surface is stored, and after the mirror surface is rotated to the desired position as described above, the mirror surface is rotated in response to an operation command (for example, operation of a return switch). It is conceivable to provide a mirror control device having a structure for automatically returning the main body to the storage position, and FIG. 4 shows a schematic structure of the mirror control device.

That is, in FIG. 4, reference numeral 1 denotes a mirror assembly unit for rotating the mirror body 2 and thus its mirror surface 2a in addition to the mirror body 2 rotatably supported in a mirror housing (not shown). The DC drive type motor 3 and the position sensor 4 that detects the rotational position of the mirror surface 2a and outputs the position signal Sp indicating the rotational position. Actually, two motors 3 are provided for rotating the mirror surface 2a in the left-right direction and the vertical direction, respectively, and two position sensors 4 are provided accordingly. Reference numeral 5 denotes a control circuit electrically connected to the mirror assembly unit 1 described above, which comprises the following components. That is, 6 is an input processing circuit for matching the position signal Sp from the position sensor 4, and 7 is a storage circuit that stores a specific rotation position of the mirror surface 2a (normal use position in this case). From now on, the specific position signal Sc indicating the specific rotation position is output. 8 is the position signal S that has passed through the input processing circuit 6
p is a comparison circuit that compares p with the specific position signal Sc from the storage circuit 7, and the comparison output is given to the determination circuit 9. This judgment circuit 9 is used for normal / reverse rotation of the motor 3 (normal / reverse energization).
Is controlled via the driver 10, and when the operation command signal is given from the return switch 11, the motor 3 is energized and driven until the comparison output of the comparison circuit 9 coincides with each other. 2a is configured to rotate to a specific rotation position indicated by the specific position signal Sc. Actually, a part of the internal circuit of the control circuit 5 is replaced with the program of the microcomputer.

(Problems to be Solved by the Invention) In the above-described conventional configuration, it is necessary to rotate the mirror body 2 by, for example, freezing the water that has entered the mirror assembly unit 1 or mixing foreign matter into the unit 1. Although the torque is often increased, in such a state, the motor 3 may fall into an overload state, and the motor 3 may be overheated and its life may be shortened. . In order to deal with such a problem, conventionally, a current detection means for detecting the load current of the motor 3 is provided, and the current detected by the current detection means is set to a predetermined value due to the lock or overload state of the motor 3. A configuration is adopted in which the motor 3 is cut off when the voltage rises above a value. However, with this configuration, a new problem arises in that the current detection means is separately required and the overall configuration becomes complicated. Further, conventionally, the energization required time of the motor 3 when the mirror body 2 is rotated in the maximum range is preset in the timer means, and the continuous energization time of the motor 3 exceeds the time set in the timer means. When the motor 3 is turned off, the motor 3 is cut off. However, in this structure, when the motor 3 falls into an overload state, the motor 3 is not operated until the set time elapses. Therefore, it cannot be said that the above-mentioned problems such as the overheating of the motor 3 and the shortening of the service life associated therewith can be sufficiently solved.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably prevent overheating of a motor for rotating a mirror surface and a reduction in service life thereof without complicating the structure. An object of the present invention is to provide a control device for an electric mirror for an automobile capable of performing the above.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention outputs a position signal output from a position sensor indicating a rotational position of a mirror surface and a position signal indicating a specific rotational position. On the basis of the comparison with the above, in a control device for an electric mirror for an automobile, which comprises a control circuit for driving the mirror surface rotating motor to rotate the mirror surface to the specific rotation position, A speed calculation means for calculating a rotation speed of the mirror surface based on a position signal from the position sensor, and turning off the motor when a calculation result by the speed calculation means is equal to or lower than a preset limit speed. It is configured to include a motor stopping means.

(Operation) When the torque required to rotate the mirror surface increases, the rotation speed of the mirror surface decreases.
On the other hand, the speed calculating means in the control circuit calculates the rotation speed of the mirror surface based on the position signal from the position sensor, and the calculation result is the rotation speed of the mirror surface as described above. When the speed becomes equal to or lower than the preset limit speed according to the decrease of the electric current, the motor stop means in the control circuit will turn off the motor. Therefore, the situation in which the motor is energized in the overloaded state is eliminated early, and the overheating and the shortened life of the motor can be reliably prevented. In this case, the information necessary for disconnecting the motor as described above, that is, the rotation speed of the mirror surface, is obtained by using the position sensor originally required for controlling the rotation of the mirror surface. Therefore, the structure is not complicated.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. However, since this embodiment includes the same components as those in FIG. 4, the same reference numerals are given to those components and the description thereof will be omitted.

In FIG. 1, which schematically shows the entire electrical configuration in the form of a combination of functional blocks, 12 is a control circuit, which is the fourth circuit.
The input processing circuit 6, the storage circuit 7, the comparison circuit 8 shown in the figure,
In addition to the judgment circuit 9 and the driver 10, it is configured to include an arithmetic processing circuit 13 having the functions of a speed calculation means and a motor stop means according to the present invention. In this case, the judging circuit 9 is adapted to receive a stop command signal Soff output from the arithmetic processing circuit 13 as will be described later, and when receiving the stop command signal Soff, the determination circuit 9 sends a signal to the motor 3 via the driver 10. It is designed to stop energization. The arithmetic processing circuit 13 is actually realized by a program of a microcomputer, and is based on a position signal Sp given through the input processing circuit 6 and a program stored in advance as shown in FIG. It is designed to control.

Now, in the following, the control content of the arithmetic processing circuit 13 will be described with reference to FIG. That is, the arithmetic processing circuit 133 cyclically executes a routine including steps a to e described below in a constant cycle while the motor 3 is energized. First, in step a, the position signal Sp from the position sensor 4 is read, and in the next step b, the mirror surface 2a indicated by the position signal Sp is read.
The position is stored as position information Pn at time tn. Next, in step c, the position information Pn and the time t _n-1
The absolute value Pz of the difference from the position information P _n-1 of the mirror surface 2a at (execution time of step b one cycle before) is calculated. At this time, since the time difference T between the time t _n-1 and the time tn is constant, the absolute value Pz (= | Pn-P _n-1 |) calculated as described above.
Corresponds to the rotation speed of the mirror surface 2a.

Then, in the subsequent step d, the absolute value Pz is
Is less than or equal to a preset movement amount q. In this case, when the mirror assembly unit 1 is in a normal state (the state shown by the solid line in FIG. 3) as shown in FIG. 3 which shows the position change state of the mirror surface 2a according to the energization of the motor 3, The amount of movement per time T is represented by Q. On the other hand, when an abnormality occurs in the mirror assembly unit 1 and the torque required to rotate the mirror body 2 increases, the rotation speed of the mirror surface 2a decreases (indicated by a broken line in FIG. 3). State), and the amount of movement of the mirror surface 2a per time T decreases to q or less. This movement amount q corresponds to the limit speed of the mirror surface 2a, and accordingly, in the step d, it is judged whether or not the rotation speed of the mirror surface 2a is equal to or lower than the limit speed.
When "YES" is determined in the above step d, that is, when the rotation speed of the mirror surface 2a is less than or equal to the limit speed, the stop command signal Soff is output in step e to energize the motor 3 by the driver 10. To stop. When it is determined to be "NO" in step d, the above step e is jumped and the process returns to step a, after which the above-described operation is repeated.

In short, the arithmetic processing circuit 13 causes the mirror body 2 to rotate due to an abnormal state such as freezing of water that has entered the mirror assembly unit 1 or mixing of foreign matter into the unit 1. When the torque required for is increased, it is detected that the rotation speed of the mirror surface 2a has become less than or equal to the limit speed, and the motor 3 is stopped by disconnection.
As a result, the situation in which the motor 3 is energized and driven in the overloaded state can be eliminated at an early stage, and the overheating of the motor 3 and the shortened life thereof can be reliably and effectively prevented. Of course, even when a person's finger is caught between the mirror body 2 and the mirror housing accommodating the mirror body 2, the motor 3 is immediately cut off and the safety is improved. Further, the information for stopping the disconnection of the motor 3 as described above, that is, the information necessary for obtaining the rotation speed of the mirror surface 2a is originally necessary for the rotation control of the mirror surface 2a. Since it is obtained by using the position signal Sp from the position sensor 4, the overall configuration is not complicated. In this case, in particular, the arithmetic processing circuit 13
Since the above function is obtained by the program of the microcomputer forming the control circuit 12, there is no need to add a hardware configuration and the cost can be reduced.

In the above embodiment, the limit speed of the mirror surface 2a is set in only one step, but if it is set in a plurality of steps, various abnormal states can be appropriately dealt with. .

[Effects of the Invention] According to the present invention, as is apparent from the above description, a motor for rotating the mirror surface and a position signal indicating the rotation position of the mirror surface are detected. A control circuit for rotating the mirror surface to the specific rotation position by driving the motor based on a comparison between a position sensor for outputting and a position signal from the position sensor and a command signal indicating the specific rotation position. In the control device for an electric mirror for an automobile including the above, the present invention has an excellent effect that it is possible to surely prevent the above-mentioned motor from overheating and the resulting shortening of the life without complicating the structure.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a block diagram showing an electrical configuration, FIG. 2 is a flow chart showing a main part of control contents, and FIG. 3 is a mirror surface. It is a characteristic view showing the position change state of. Further, FIG. 4 is a view corresponding to FIG. 1 showing a conventional example. In the figure, 1 is a mirror assembly unit, 2 is a mirror body, 2a is a mirror surface, 3 is a motor, 4 is a position sensor, 7
Is a storage circuit, 8 is a comparison circuit, 9 is a determination circuit, 12 is a control circuit, and 13 is a signal processing circuit (speed calculation means, motor stop means).

Claims (1)

[Claims] 1. A motor for rotating a mirror surface, a position sensor for detecting a rotation position of the mirror surface and outputting a position signal indicating the rotation position, and a position signal from the position sensor. A control device for an electric mirror for an automobile, comprising: a control circuit that rotates the mirror surface to the specific rotation position by driving the motor based on a comparison with a command signal indicating a specific rotation position. The control circuit
Speed calculation means for calculating the rotation speed of the mirror surface based on the position signal from the position sensor, and a motor for disconnecting the motor when the calculation result by the speed calculation means is below a preset limit speed. A control device for an electric mirror for an automobile, comprising: a stopping means.