JPH0132191Y2 - - Google Patents

Description

[Detailed description of the invention] This invention uses the rotation of a cam having a plurality of cam grooves to control the rotation of a cam motor that rotates the cam in a magnetic recording device such as a tape recorder that drives a head stand, a pinch roller, etc. The present invention relates to a rotational position control device for a cam drive motor in a magnetic recording device that detects and controls the rotational position of a cam drive motor.

Conventionally, there has been a device of this type as shown in FIG. In FIG. 1, 1 is a cam having gears around it, 2 is a gear formed coaxially with the cam 1, 3 is a cam drive motor, and a pulley 4 and a gear 5 formed coaxially with the pulley 4. A driving force is applied to the cam 1 through the cam 1. A potentiometer 6 detects the rotation of the cam 1 and outputs a voltage according to its rotational position. 7a, 7b, and 7c are comparison circuits whose comparison voltages are V ₁ , V ₂ , and V ₃ respectively.
different from. A control circuit 8 controls the rotational position of the cam drive motor 3 based on the outputs of the comparison circuits 7a, 7b, and 7c.

With the above configuration, when the cam 1 rotates, the potentiometer 6 supplies an output corresponding to the rotational position to the comparison circuits 7a, 7b, and 7c. In the comparison circuit 7a, the potentiometer 6
When the output from the cam drive motor 3 reaches _V1 , a stop mode signal is supplied to the control circuit 8 to stop the cam drive motor 3. Similarly, when the output of the potentiometer 6 becomes V ₂ or V ₃ , the comparison circuits 7 b and 7 c output a fast-forward mode signal and a play mode signal, respectively, and the control circuit 8 stops the cam drive motor 3 .

However, if the above-mentioned conventional device is applied to a device having a large number of modes, such as a reverse type tape recorder, the number of comparison circuits must be increased, resulting in an increase in cost.

The present invention was made to eliminate the drawbacks of the conventional ones as described above, and it determines the rotation speed of the cam drive motor, its rotation direction, the reference position, and in which rotation direction it is currently stopped from the reference position. A rotational position control device for a cam drive motor in a magnetic recording device that controls the rotational position of a cam drive motor by providing four detection devices for detecting the presence of an animal, and is capable of highly accurate position detection with a simple configuration. is intended to provide.

An embodiment of this invention will be described below with reference to FIGS. 2, 3, and 4. In Figure 2, 1
a, 1b are cams provided so that the surrounding gears mesh with each other; 4' is a detection pulley having a slot around it; 9, 10 is a photo sensor for detecting the slot around the detection pulley 4';
Reference numeral 1 denotes photo sensors disposed above and below the cam 1a, and a fan-shaped hole 12 provided on the cam 1a.
The photo sensor 9 is set to count pulses while the fan passes through the photo sensor 11 due to rotation, and while the fan-shaped hole 12 passes the photo sensor 11 (at this time, the output of the photo sensor 11 The cam grooves (not shown) of the cams 1a and 1b are formed so that the output (is at a low level as shown by output 3 in FIG. 3) is in the stop mode. Further, 13 is a leaf switch, which is an end cam (not shown) provided on the cam 1b.
It is configured to turn on and off depending on the
A control circuit 15 controls the cam drive motor 3 using output pulses obtained from the photo sensors 9, 10, 11 and the leaf switch 13. In addition, FIG. 3 shows the photo sensors 9, 10,
11 and the leaf switch 13, output 1 is the output pulse of the photo sensor 9, output 2 is the output pulse of the photo sensor 10, output 3 is the output pulse of the photo sensor 11, and output 4 is the output pulse of the leaf switch 13. shows the output pulse of

Here, the photo sensors 9 and 10 are installed so as to output pulses with a 1/4 period phase shift, as shown in FIG.
By counting the output pulses shown in , the rotational positions of cams 1a and 1b can be determined, and from outputs 1 and 2 from photo sensors 9 and 10, cam 1
The rotation directions of a and 1b are known. That is, when the detection pulley 4' is rotating clockwise,
When the falling part X of the pulse of output 1 in FIG. 3 falls within the high level period of the pulse of output 2 and the detection pulley 4' is rotating counterclockwise,
The positions of the photo sensors 9 and 10 are determined so that the trailing edge X' of the output 1 pulse in FIG. 3 is within the low level period of the output 2 pulse. Here, the pulse count -6 to 6 counted by the photo sensor 9 while the sector-shaped hole 12 passes the photo sensor 11 is set as the stop mode, and the pulse count 86 to 96 (pulse count -86 to -96) is set as the forward mode. (reverse mode), and pulse count 18 to 30 (pulse count -18 to -30) is set to rewind mode (first forward mode).

The above modes have a positional relationship as shown in FIG. 4 on the actual cam. In Fig. 4, numeral 14 is a cam shown simply for explanation, and when this cam rotates once, the pulse count is -96 to 96 (in addition, the pulse count is -96).
96 and pulse count 96 are at the same position. ) That is, 192 pulses are counted by the photo sensor 9. As shown in FIG. 4, the position of each mode is determined by the count of the photo sensor 9. Here, since the stopping position shifts due to the inertia of the motor, a certain width is provided. First, the stop mode position is determined by the pulse of output 3 shown in FIG. Next, when entering the rewind mode, this cam 14 rotates counterclockwise and when the photo sensor 9 counts 43 pulses, the control circuit 15 supplies a reversal signal to the cam of the cam drive motor 3, the cam is reversed, and the rewind is started. Enter the mode and stop. Instead of directly entering the rewind mode from the stop mode, a cam claw is provided so that the rewind mode is reversed and entered after passing the rewind mode position as described above. This is to avoid entering rewind mode midway when the mode changes from stop mode to forward mode. Also, even if a reversal signal is supplied to the cam motor after actually counting 43 pulses, it will not reverse immediately, but the reversal position will shift due to inertia. Furthermore, the rotational direction of the cam is detected by outputs 1 and 2 of photo sensors 9 and 10.

When counting these pulses, be sure to use the stop mode position (rotation reference position, i.e., the point where the output of the photo sensor 11 becomes low level) as a reference, and then count the pulses after the output 3 in Figure 3 goes from low level to high level. The pulse of output 1 is set to 7 or -7, and counting is performed using this value.

As shown in Fig. 3, the leaf switch 13 is installed to turn on and off when the output of the photo sensor 11 is at a low level. It detects whether it is stopped at a point where it is turned or whether it is stopped at a point where it has turned clockwise. That is, when the pulse count shown in output 1 in FIG. 3 is a positive value, it is a low level, and when it is a negative value, it is a high level. This is to know the rotational position of the cam when the power is turned on. In other words, when the power is turned on, the count number is not known at all, but as mentioned above, the stop mode position is fixed, so you can know which direction to rotate to return the cam to the stop mode position faster. The output of the leaf switch 13 is detected and the control circuit 15 uses the output to rotate the cam drive motor 3 in a desired direction.

As mentioned above, the present invention includes the cam drive motor 3,
A cam 1 that rotates in conjunction with the cam drive motor 3.
In a magnetic recording device such as a tape recorder whose mechanism is operated by a and 1b, the number of rotations of the cam drive motor 3, its rotation direction, a rotation reference position, and which rotation direction is currently being moved from the rotation reference position. Photo sensor 9, 1 that detects whether it is stopped
0, 11 and a leaf switch 13, and a control circuit 15 that controls the cam drive motor 3 based on the output of the detection device, and the rotation of the cam drive motor is controlled by the detection device. Since the position is controlled, highly accurate position detection and control is possible with a very simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a conventional rotational position control device for a cam drive motor, Fig. 2 is a plan view showing an embodiment of the present invention, and Figs. 3 and 4 illustrate an embodiment of the present invention. It is a time chart and an explanatory diagram for doing so. 1a, 1b... cam, 3... cam drive motor,
9, 10, 11...Photo sensor, 13...Leaf switch, 15...Control circuit.

Claims (1)

[Scope of utility model registration request] In a magnetic recording device such as a tape recorder in which a mechanism is operated by a cam drive motor and a cam that rotates in conjunction with the cam drive motor, the number of rotations of the cam drive motor, its rotation direction, and rotation reference position are determined. , four detection devices for detecting in which rotational direction the rotational reference position is currently stopped;
A cam drive motor in a magnetic recording device, comprising: a control circuit that controls the cam drive motor based on the output of the detection device, and the rotational position of the cam drive motor is controlled by the detection device. Rotary position control device.