JP2002027771A - Brake for dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply brake in order to lighten impart on the occasion of reverse rotation by a spring which occurs when a motor is stopped, in a mechanism which is operates by the reciprocating movement of an actuator to be moved by the motor. SOLUTION: A zener diode is connected in parallel with the motor. Consequently, current generated by the reverse rotation of the actuator by the spring which occurs when the operation of the motor is stopped, is made to act as a brake against the reverse rotation of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor brake for driving an actuator or the like that reciprocates.

[0002]

2. Description of the Related Art A conventional example of an apparatus which uses an actuator or the like which reciprocates by driving a DC motor and uses the operation thereof will be described as an example using a shutter opening / closing apparatus.

FIG. 1 shows a configuration in which a brake device of the present invention, which will be described in detail later, is applied to a shutter opening / closing device. A conventional shutter device without the brake device of the present invention also has an electric motor for driving a motor. The mechanical parts other than the circuits and the like have the same configuration as those shown in FIGS. 1 (A), 1 (B) and 1 (C). Accordingly, the description of the conventional example will be described with reference to FIGS. 1A, 1B, and 1C, and FIG.
It will be described based on the above.

[0004] Of (A), (B), and (C) in Fig. 1, (A) is a driving unit, (B) is a state in which a shutter is closed, and (C) is a state in which the shutter is open. Is shown. FIG. 8 shows an electric circuit for driving a DC motor.

In FIGS. 1A, 1B, and 1C,
1 is a motor, 3 is a pinion fixed to the output shaft 2 of the motor 1, 4, 5 and 6 are gears, 7 is a drive shaft, 8 is a spring fixed to the drive shaft 7 and acting in the direction to reverse the motor 1. (Spring), 9 is a drive lever (actuator) fixed to the drive shaft 7, 10 is a stopper, 11 is a rotary shutter, 12 is another stopper, 13, 14 are window vertical members, 15 is a shutter shaft,
Reference numeral 16 denotes a drive pin provided on the drive lever 9.

In the circuit shown in FIG. 8, 1 is a motor, and 18 is a switch.

In this shutter opening and closing device, when the switch 18 shown in FIG. 8 is turned on to drive the motor 1, the pinion 3 fixed to the output shaft 2 rotates, and the rotating shaft 7 rotates against the force of the spring 8. Then, the drive lever 9 moves the shutter 11 to the right and the drive lever 9 hits the stopper 12 and stops. This opens the window as shown in FIG.

On the other hand, when the switch 18 is turned off to stop driving the motor 1, the rotation shaft 7 is rotated in the opposite direction by the force of the spring 8, and the drive lever 9 is rotated in the opposite direction, that is, in FIG. Rotate counterclockwise to rotate shutter 11
Closes.

In this shutter opening / closing device, as shown in FIG. 1C, in order to keep the shutter 11 open, it is necessary to keep the voltage applied to the motor 1.

When the motor 1 is driven to maintain the shutter 11 in the open state as described above, the motor 11 is overheated. In some cases, a process such as detecting an overcurrent at the time of hitting the stopper 12 and lowering the voltage applied to the motor 1 is performed.

In order to close the shutter in this shutter device, the switch 18 is turned off and the voltage applied to the motor 1 is turned off, so that the rotational force of the motor 1 is lost and the force stored in the spring 8 As a result, the motor 1 is reversed via the gears 6, 5, 4 and the pinion 3, and the drive lever 9 rotates counterclockwise and hits the stopper 10 and stops. This drive lever 9
, The shutter 11 closes the window opening 17.

As described above, in the electric circuit shown in FIG. 8, the switch 18 is turned off to stop the driving portion of the motor 1, and the driving lever 9 is rotated counterclockwise by the force of the spring 8 shown in FIG. When the window opening 17 is closed by the shutter 11, the counterclockwise rotation of the drive lever 9 is gradually accelerated and then hits the stopper 10 and stops. At this time, the driving lever 9 has a very high rotation speed and is stopped suddenly by the stopper 10, so that each member, that is, the driving lever 9, the stopper 10, the gears 6, 5, 4,. It is necessary to strengthen the pinion 3 and the like. Therefore, there are drawbacks such as an increase in the size of the entire apparatus and an increase in cost.

[0013]

SUMMARY OF THE INVENTION The present invention relates to an apparatus provided with a reciprocating mechanism driven by a DC motor.
It is an object of the present invention to provide a device in which a reverse rotation movement by a spring is automatically braked when a motor is turned off.

[0014]

A brake device according to the present invention comprises a motor, a spring mounted on a rotating shaft rotated by driving the motor, and a reciprocally movable actuator fixed to the rotating shaft. The actuator is rotated in one direction by the rotation of the rotating shaft in one direction by the driving of the motor, and by stopping the driving of the motor, the rotating shaft is rotated by the action of the spring to reverse the actuator. In a mechanism that rotates in the direction, a zener diode is connected in parallel with the motor, and when the driving of the motor is stopped, the motor is reversely rotated by the spring when the motor is stopped. And act as a brake.

[0015]

Embodiments of the present invention will be described.

FIG. 1 is a view showing a first embodiment of the present invention, in which (A) is a view showing a configuration of a drive section, (B) is a view showing a state in which a shutter is closed by this drive section, (C)
FIG. 4 is a diagram showing a state in which a shutter is opened, and FIG. 4D is a diagram showing an electric circuit for driving a motor.

The first embodiment of the present invention has a structure as shown in FIGS. 1A, 1B and 1C.
A circuit as shown in (D) is used as the electric circuit.

First, the overall configuration shown in FIGS. 1A, 1B and 1C will be described. In these figures, 1 is a motor, 3 is a pinion fixed to the output shaft 2 of the motor 1, 4, 5, and 6 are gears, 7 is a drive shaft, and 8 is a drive shaft 7.
, A spring (spring) acting in a direction to reverse the motor 1, 9 a drive lever (actuator) fixed to the drive shaft 7, 10 a stopper, 1
1 is a rotary shutter, 12 is another stopper, 1
Reference numerals 3 and 14 denote window upper and lower members, 15 denotes a shutter shaft, and 16 denotes a drive pin provided on the drive lever 9. FIG.
In (D), 18 is a switch, 19 is a Zener diode, and 20 is a resistor.

In this shutter opening / closing device, FIG.
When the motor 1 is driven by turning on the switch 18 shown in (D), the pinion 3 fixed to the output shaft 2 rotates, the rotating shaft 7 rotates against the force of the spring 8, and the driving lever 9 rotates.
Moves the shutter 11 clockwise and the drive lever 9 hits the stopper 12 and stops. This allows
The window is opened as shown in FIG.

On the other hand, when the switch 18 is turned off to stop driving the motor 1, the driving lever 9 rotates in the reverse direction by the force of the spring 8 and stops against the stopper 12. Further, the output shaft 2 of the motor 1 is reversely rotated via the gears 6, 5, 4 and the pinion 3 by the rotation of the drive lever 9 in the reverse direction.

Here, the electric circuit is as shown in FIG. 1D. The Zener diode 19 has a Zener voltage selected sufficiently higher than the power supply voltage E. When the switch 18 is turned on, the Zener diode 19 is different from the conventional example. Works exactly the same.

When the driving of the motor 1 is stopped (when the switch 18 is turned off), the motor 1 is reversed by the spring 8. At this time, the motor 1 becomes a generator, and the generated voltage increases in proportion to the rotation speed, and when the rotation speed exceeds a certain rotation speed, a current flows through the Zener diode, thereby suppressing the motor 8 from increasing the reverse rotation speed by the spring 8. This serves as a brake, thereby suppressing an increase in the number of rotations of the rotating shaft 7 and reducing the impact when the drive lever hits the stopper.

In the illustrated electric circuit, the resistor 20 is for preventing heat loss of the Zener diode 19,
It is not necessary to use it.

Next, a case where the motor 1 of the above-described device is a brushless motor will be described. That is, a shutter device in which a motor for driving the device is a brushless motor will be described.

A brushless motor is a motor that uses a commutator and a brush to rotate, while a general DC motor rotates by switching an electric current by an electronic circuit. The brushless motor has an advantage of a very long life. It is used when reliability is required.

Even when this brushless motor is used, the mechanical structure shown in FIGS. 1A, 1B and 1C does not change, so that the electrical part will be described.

FIG. 2 shows a configuration of a general three-phase brushless motor, in which 18 is a switch, 21 is a control circuit, and 22 is a coil.

In FIG. 2, when the switch 18 is turned on, the control circuit 21 controls the current flowing through the coil 22 to rotate the motor. Here, since the motor is a three-phase motor, three coils 22 are shown in FIG.
Some use multiple coils.

In contrast to the general three-phase motor shown in FIG. 2, according to the present invention, as shown in FIG.
And are connected in series. Here, the resistor 20 need not be used.

FIG. 4 shows another example in which the present invention is applied to a brushless motor, in which diodes 19 are connected in parallel.

FIG. 5 shows another third example in which a diode is connected between one coil and the ground.

FIGS. 6 and 7 show a case where one varistor 23 is used instead of two Zener diodes.

In the case of a two-phase brushless motor other than a three-phase brushless motor, the apparatus of the present invention can be constituted by using one or more sets of zener diodes or one or more varistors.

In particular, if the present invention is applied to a device using a brushless motor, not only can the shock when the actuator hits the stopper pin at the time of stoppage be reduced, but also the electronic components of the control circuit such as transistors and ICs can be reduced by the high voltage generated. It can prevent damage.

The embodiment of the apparatus of the present invention described above is as follows.
It is related to the shutter device, but not limited to this.
What is necessary is just a device provided with the actuator which reciprocates. For example, the present invention can be used for other devices such as an automatic opening / closing device in a water tap in a washroom.

[0036]

According to the present invention, the impact is reduced by the braking effect of the reverse rotation of the output shaft of the motor at the time of reverse rotation by the spring (spring), thereby avoiding an increase in the size and cost of the device due to strengthening of parts. Small and low cost actuators.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows a general three-phase brushless motor.

FIG. 3 is a diagram showing a three-phase brushless motor and an electric circuit used in the embodiment of the present invention.

FIG. 4 is a diagram showing another three-phase brushless motor and an electric circuit used in the embodiment of the present invention.

FIG. 5 is a diagram showing another three-phase brushless motor and an electric circuit used in the embodiment of the present invention.

FIG. 6 is a diagram showing an example in which a varistor is used instead of a Zener diode in a three-phase motor and an electric circuit.

FIG. 7 is a diagram showing an example in which a varistor is used in a three-phase motor and an electric circuit.

FIG. 8 is a conventional motor and electric circuit diagram used for a shutter device and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Motor output shaft 3 Pinion 4, 5, 6 Gear 7 Rotary shaft 8 Spring 9 Drive lever

Claims (4)

[Claims] 1. A motor, a spring attached to a rotating shaft rotated by the driving of the motor, and a reciprocally movable actuator fixed to the rotating shaft, one of the rotating shaft driven by the motor. A mechanism in which the actuator is turned in one direction by turning in the direction, and the actuator is turned in the opposite direction by rotating the rotation shaft by the action of the spring by stopping the driving of the motor, A brake device in which a zener diode is connected in parallel with the motor, and when the driving of the motor is stopped, a current generated by the motor rotating reversely by the spring acts as a brake against the reverse rotation of the motor. 2. A motor, a spring attached to a rotating shaft rotated by the driving of the motor, and a reciprocally movable actuator fixed to the rotating shaft, one of the rotating shaft driven by the motor. A mechanism in which the actuator is turned in one direction by turning in the direction, and the actuator is turned in the opposite direction by rotating the rotation shaft by the action of the spring by stopping the driving of the motor, The motor is a brushless motor, two zener diodes are connected between at least one coil of the motor and ground, and a current generated when the motor is reversely rotated by the spring when the driving of the motor is stopped. Will act as a brake against reverse rotation of the motor Seat brake device. 3. The brake device according to claim 2, wherein said two Zener diodes are connected in parallel to a coil. 4. The brake device according to claim 2, wherein a varistor is connected in place of said two Zener diodes.