JPS62261398A - Brake device of dehydration motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a dewatering motor braking device that electrically brakes the dewatering motor in order to stop a dewatering tank rotating by inertia. .

(Prior Art) A braking device for a dewatering motor that employs an electric braking force type has advantages such as no wear compared to a mechanical braking system that uses a brake shoe in pressure contact with a drum. Therefore, conventionally, a DC braking method has been considered in which a DC voltage obtained by rectifying an AC power source is applied to the windings of a dewatering motor during inert rotation.

However, in general, the direct current braking system has a property that the braking force increases as the rotational speed of the motor and the applied voltage increase. However, in the past, a constant DC voltage was applied over the entire braking period, so an excessive braking force was applied at the beginning of braking when the motor was still inertly rotating at high speed, and as the rotation speed decreased, the braking force increased. There was a tendency for the power to decrease rapidly. This has the disadvantage that the excessive braking force applied at the beginning applies a large shock to the motor and the dehydration tank, and furthermore, the reduction in braking force in the latter stages of braking takes a long time for the dehydration tank to completely stop.

(Problems to be Solved by the Invention) As described above, in the dehydration motor braking device that employs the conventional electric braking method, there is a problem that the shock at the beginning of braking is large and it takes a long time to reach the stop. There was.

The present invention has been made to solve the above-mentioned problems, and therefore, its purpose is to brake a dewatering motor that can stop a dewatering tank in as short a time as possible without applying an excessive shock at the beginning of braking. We are here to provide you with the equipment.

[Structure of the Invention] (Means for Solving the Problems) A braking device for a dehydration motor according to the present invention includes a DC braking means that applies a DC voltage that gradually increases to the windings of a dehydration motor; A reverse phase braking means is provided for applying an alternating current voltage to the windings of the motor so as to generate torque in a direction opposite to that during operation, and the direct current braking means is operated by a timer means at the beginning of braking, and then the reverse phase braking means is activated. The feature is that it is activated.

(Function) At the beginning of braking, the timer means activates the DC braking means, and since this DC braking means gradually increases the voltage applied to the motor windings, the rotor is initially rotating at high speed. Even with the IC, there is no shocking braking force. Even if the rotational speed of the rotor decreases due to the operation of the DC braking means and its braking force tends to decrease, the timer means then activates the reverse phase braking means, so even if the rotational speed of the rotor is low, the large υ1
Power can be applied and rapid deceleration is possible.

(Example) Hereinafter, an example in which the present invention is applied to a dehydrator of a so-called two-tub type washing machine will be described with reference to the drawings.

In FIG. 1, 1 is an AC power supply, and 2 is a dewatering motor constituted by a capacitor run type single-phase induction motor capable of forward and reverse rotation. Both bus bars 1a of the AC power supply 1.

A lid switch 3, a timer switch 4, and a relay coil 5 are connected in series between the terminals lb and lb. The lid switch 3 is closed when a lid 115 for opening and closing a dehydration tank (not shown) is closed, and is opened when the lid is opened.

The timer switch 4 is closed when a dehydration timer (not shown) is set, and is opened when the set dehydration time has elapsed. 6 to 8 are first to third relay switches operated by the relay coil 5. The common contact 6C of the first relay switch 6 is the normal rotation terminal 2 of the motor 2.
The normally open contact 6a is connected to the over-connection point of the timer switch 4 and the relay coil 5. The common contact 7c of the second relay switch 7 is connected to the common terminal 2c of the dehydration motor 2. , the normally open contact 7a is connected to the bus bar 1b of the AC power supply 1. Therefore, as shown in FIG.
When both the lid switch 3 and the timer switch 4 are closed, the relay coil 5 is energized, so the first
The normally open side of each second relay switch 6.7 is closed, and the normal rotation terminal 2a and common terminal 2C of the motor 2 are connected to the AC power supply 1.
The motor 2 rotates in the forward direction. Further, the third relay switch 8 is of a normally closed type, and when the lid switch 3 or the timer switch 4 is opened and the motor 2 is de-energized, the relay coil 5 is simultaneously de-energized. It closes and gives a trigger signal to the timer means 9. When the timer means 9 is given a trigger signal, the timer means 9 controls the first to fifth clocks in the order described later.
The sequential switches 10 to 14 are activated.

Now, the first and second sequential switches 10°1
1 constitutes a reverse phase braking means 15, and a normally open first
The sequential switch 10 is connected to the bus line 1a of the AC power supply 1.
and the reversing terminal 2b of the motor 2, and the normally open contact 11a and the common contact 11c of the second sequential switch 11 are connected to the bus bar 1b of the AC power supply 1 and the normally closed contact 7b of the second relay switch 7, respectively. It is connected to the. Therefore, each of the first and second sequential switches 10, 1
1 operates and switches to the normally open side, bus 1 of AC power supply 1
a is connected to the reverse terminal 2b of the motor 2, and the bus bar 1b is connected to the common terminal 2c, so that an AC voltage is applied to the windings of the motor 2 so as to generate torque in the opposite direction to that during dehydration operation. applied.

Next, 16 is a DC braking means, which includes a rectifier circuit 17 having four diodes connected in a bridge, and a time constant circuit 20 comprising a resistor 18 and a capacitor 19 connected to the DC output side of the rectifier circuit 17. The AC input side of the rectifier circuit 17 is
One side is directly connected to the bus bar 1a, and the other side is a normally open third
It is connected to the bus bar 1b via a sequential switch 12. Further, one terminal of the capacitor 19 is connected to the normally closed contact 6b of the first relay switch 6 via the normally open fourth sequential switch 13, and the other terminal of the capacitor 19 is connected to the normally closed contact 6b of the first relay switch 6 via the normally open fourth sequential switch 13. It is connected to the normally closed contact 11b of the switch 11. The fifth sequential switch 14 is of a normally open type and is connected in parallel so as to bypass the resistor 18.

Next, the operation of this embodiment will be explained with reference to FIG. 2 as well.

When the lid switch 3 and the timer switch 4 are both closed, the relay coil 5 is energized and the first and second
Since each relay switch 6.7 is switched to the normally open side (see FIG. 1), an alternating current voltage is applied to the forward rotation terminal 2a of the motor 2, and the motor 2 rotates at high speed in the forward direction. Here, when the lid of the dehydration tank is opened and the lid switch 3 is turned off, or when the dehydration timer finishes measuring operation and the timer switch 4 is turned off, the motor 2 is cut off and the dehydration tank becomes inert. The dehydration tank is braked in the following manner in order to immediately stop the dehydration tank which rotates due to inertia. First, when the lid switch 3 or the timer switch 4 is turned off, the relay coil 5 becomes de-energized and the first and second relay switches 6.7 are turned to the normally closed side (6b, 7b).
), and the eleventh third relay switch 8 is turned on (times t, o in FIG. 2). Then, as a trigger signal is given to the timer means 9 by turning on the third relay switch 8, the timer means 9 immediately turns on the third and fourth sequential switches 12 and 13 and operates the DC braking means 16. .

When the third sequential switch 12 is turned on, a DC voltage obtained by rectifying the AC power source 1 is output to the DC output side of the rectifier circuit 17. A time constant circuit 20 is connected to the rectifier circuit 17, and the capacitor 19 is a resistor. 18, the terminal voltage of the capacitor 19 is as shown in Fig. 2 (B).
gradually rises as shown in . Here, the first and second
The relay switch 6.7 is switched to the normally closed side,
In addition, the second sequential switch 11 is on the normally closed side (11
(b-11c closure) (see Figure 2 (A)),
Both terminals of the capacitor 19 are the forward rotation terminal 2a of the dehydration motor 2.
and is connected to the common terminal 2C. Therefore, at the beginning of braking, a DC voltage that gradually increases is applied to the windings of the motor 2 by the IJi flow braking means 16 as shown in FIG. 2(B).

This causes a braking force to act on the rotor of the motor 2, but since the initially applied voltage is small, this braking force does not act impulsively and acts while increasing relatively slowly. However, since the rotor is initially rotating at high speed, this braking force is sufficient to decelerate the dehydration tank. Thereafter, when a predetermined period of time has elapsed (time t1), the timer means 9 causes the fifth
The sequential switch 14 is turned on, so that the full output voltage of the rectifier circuit 17 is applied to the windings of the motor 2, and as a result, the motor 2 is further decelerated. When the rotational speed of the rotor decreases due to the deceleration effect of the DC braking means 16, the deceleration force exerted by the DC braking means 16 gradually decreases as the rotational speed decreases.

However, this time, at time t2, the first sequential switch 10 is turned on by the timer means 9, and one second sequential switch 11 is set to the normally open side (lla-
The winding of the motor 2 is disconnected from the DC braking means 16, and the bus bar 1a of the AC power supply 1
lb are connected to the reverse terminal 2b and the common terminal 2c, respectively. As a result, a torque in the opposite direction to that during the dehydration operation is applied to the motor 2, and the rotational speed of the rotor is further reduced by so-called anti-phase braking. With anti-phase braking, even if the rotational speed of the rotor is small, a sufficient braking force can be applied to the rotor, so the rotational speed is rapidly reduced. After this, the rotational speed of the rotor approaches zero (around -1 (time t3)
), the first sequential switch 10 is turned off, and the second sequential switch 11 is switched to the normally closed side. As a result, the reverse rotation terminal 2b of the motor 2 and the common terminal 2
c is separated from the bus bars 1a and lb, and the normal rotation terminal 2a and the common terminal 2c are connected to both terminals of the capacitor 19 of the DC braking means 16. Therefore, the full output voltage of the rectifier circuit 17 is applied to the windings of the motor 2, and the rotor is completely stopped. Thereafter, at time t4, the third sequential switch 12 is turned off, thereby disconnecting the rectifier circuit 17 from the AC power supply 1, and the charge in the capacitor 19 is discharged through the windings of the motor 2, returning to the original state.

In this embodiment, in view of the fact that the DC braking method can apply a larger braking force as the rotation speed increases, the DC braking method is used to apply braking at the beginning of braking, and the applied voltage is changed over time. The first feature is that the constant circuit 20 is used to gradually increase the size. Therefore, while enabling rapid braking from the beginning of braking, it is possible to reliably prevent excessive impact force from acting on the motor 2 or the dewatering tank due to impulsive braking. The second feature of this embodiment is that after a certain amount of braking is applied using the DC braking method, anti-phase braking is applied. As a result, the DC braking method can compensate for the drawback that the braking force also decreases as the rotational speed decreases, and it is possible to apply sufficient braking force even after the rotational speed has decreased.

Therefore, the dehydration tank can be brought to a halt in an extremely short time compared to the conventional system which employs a direct current braking system over the entire braking period. Historically, the third feature of this embodiment is that DC braking is performed again after applying reverse phase braking. This is to deal with the possibility that if the reverse phase braking period is too long, the dehydration tank may start rotating in the opposite direction again after it has stopped. That is, according to this embodiment, since direct current braking is applied after reverse phase braking, it is possible to reliably stop the dehydration tank without starting it in the opposite direction. However, the present invention does not necessarily apply direct current braking at the end of the braking period, but can, for example, release the anti-phase braking after a standard period of time for stopping the anti-phase braking, or release the anti-phase braking. The rotation state of the water tank may be detected and the reverse phase braking may be released when the rotation has stopped.

In addition, the present invention is not limited to the second embodiment, and for example, in order to gradually increase the applied voltage in the DC braking means, the time constant circuit 20 may not necessarily be provided.
Alternatively, a chopper circuit may be provided on the output side of the rectifier circuit 17 so that the duty ratio of the switching element gradually increases, or a phase control type rectifier circuit may be adopted so that the control angle gradually increases. It may be configured to be large. Furthermore, when performing DC braking, it is of course possible to simultaneously apply DC voltage to both the forward rotation and reverse rotation windings of the motor, or to increase the applied voltage in stages. . The present invention can be applied not only to the dewatering motor in a two-tub washing machine, but also to a braking device for a drive motor in a dehydrating washing machine that performs washing and centrifugal dehydration using a washing and dehydrating tank.

[Effects of the Invention] As described in I- below, the present invention is characterized in that DC braking is applied by applying a gradually increasing voltage at the beginning of braking, and then reverse H1 braking is applied. As a result, it is possible to compensate for the shortcomings of the conventional DC braking system, in which the braking force initially acts as a shock and then rapidly decreases, and it is possible to shorten the braking time without applying excessive shock to the dehydration motor or dehydration tank. It has excellent effects.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a circuit diagram, and FIG. 2 is a circuit diagram.
The figure is a timing chart of each switch shown together with the voltage waveform applied to the dewatering motor. In the drawing, 1 is an AC power supply, 2 is a dehydration motor, 9 is a timer means, 15 is a reverse phase braking means, 16 is an ia flow braking means, and 20 is a time constant circuit.

Claims (1)

[Claims] 1. A DC braking means that applies a brake to a dewatering motor to stop a dewatering tank rotating by inertia, and applies a gradually increasing DC voltage to the windings of the motor, and a DC braking means during dewatering operation. anti-phase braking means for applying an alternating current voltage to the windings of the motor so as to generate torque in the opposite direction; and timer means for activating the direct current braking means at the beginning of braking and then operating the anti-phase braking means. A braking device for a dewatering motor.