JPH0819687A - Vibration isolator for fully automatic washer - Google Patents

Abstract

PURPOSE:To provide a fully automatic washer with reduced noise and vibration by suppressing resonance by suspending and supporting a vibration isolator with a variable damping ratio of the outer tub of a fully automatic washer utilizing liquid with viscosity variable by voltage or electric field. CONSTITUTION:In a washing machine suspending the outer tub 4 by a suspending rod and a vibration isolator in the outer frame, the vibration isolator conforms a spring 23 and a vibration isolating device 24, a spring 23 is section the lower part of the suspending rod and the vibration isolating device 24 is set on the upper part of the spring 23 and the outer tub 4 is supported by the upper part of the vibration isolating device 24. The vibration isolating device 24 injectes electroviscous fluid 26 in a case 25 and when an electric field is generated between a circular electrode plate 2a and an electrode 25a, the visocity of the electroviscous fluid 26 is risen to disturb movement and the damping ratio is increased by receiving the resistance of the circular electrode plate 2a. On the other hand, when the electric field is off, the damping ratio is decreased by the electroviscous fluid 26 coming to be freely movable by viscosity reducing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation device for a fully automatic washing machine.

[0002]

2. Description of the Related Art When an outer tub is suspended from the upper part of a main body by a hanging rod via a spring and is vibration-isolated and supported, if clothes are unevenly distributed, imbalance and vibration occur during a dehydration operation. When the vibration matches the natural frequency of the supported outer tank or the like, the vibration becomes extremely large, and the outer tank flies up and down or collides with the outer frame.

Therefore, conventionally, in order to prevent vibration, it is suppressed by a damping device composed of a cylinder and an elastic body.

Originally, as shown in FIG. 9 of vibration transmissibility-frequency of external force / natural frequency (hereinafter ω / ωo), the resonance point (ω / ωo is about 1) is exceeded and ω / Up to the position where ωo is √2, the damping ratio is increased to suppress the vibration due to resonance,
Ideally, after the position where / ωo is √2, the damping ratio is reduced to reduce the vibration transmissibility and suppress the vibration.
With the attenuator having this configuration, it is difficult to set the damping ratio because the damping ratio has a constant value.

[0005]

SUMMARY OF THE INVENTION In a fully automatic washing machine, in order to solve the above-mentioned problems during dehydration operation, ω / ωo
However, the vibration due to resonance is suppressed by increasing the damping ratio beyond the resonance point to the position of √2, and after the position where ω / ωo is √2, the damping ratio is decreased and the vibration transmissibility is reduced to reduce the vibration. (EN) Provided is an anti-vibration device which can suppress and further reduce noise due to vibration.

[0006]

As a means for achieving the above object, the present invention is a liquid having a normal fluidity. However, an electrorheological fluid which has a viscosity which increases when an electric field is generated and which returns to the original state when the electric field is cut off is used. The damping device is provided with means for changing the viscosity of the electrorheological fluid and varying the damping ratio depending on whether the electric field is turned on or off and the strength of the electric field.

[0007]

[Function] When performing dehydration operation in a fully automatic washing machine,
Using the above means, the vibration exceeds the resonance point
The damping ratio is increased up to the position where / ωo is √2, and ω / ωo
After the position of √2, the damping ratio is reduced to suppress resonance and vibration and further reduce noise.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a washing machine adopting one embodiment of the present invention includes a suspension rod 2 and a vibration isolator 3 including a spring 23 and a damping device 24 in an outer frame 1 made of a steel plate. The outer tank 4 made of synthetic resin is suspended. Hanging rod 2 and anti-vibration device 3
Are provided at four locations. In the outer tub 4 for washing, a dehydration tub 5 made of synthetic resin is provided.

The dewatering tank 5 is provided with a large number of dewatering holes 5a,
Further, a stirring blade 6 for moving and washing clothes is provided at the center bottom. When washing and rinsing, leave the dehydration tank 5 stationary,
The stirring blade 6 is rotated twice in the forward and reverse directions with a constant cycle to move the clothes and wash the clothes. The rotation of the stirring blade 6 and the dehydration tank 5 is performed by the drive device 7.

The drive unit 7 includes an induction motor 8 and a transmission means 9 including a pulley 9a and a belt 9b for transmitting the rotation of the motor 8 to the stirring blade 6 or the dehydration tank 5.
And rotating only the stirring blade 6 at the time of washing and rinsing,
Alternatively, it comprises a clutch device 10 for rotating the dehydration tank 5 during dehydration, a solenoid 7a for switching the dehydration tub 5, and a drainage device 11 for drainage. A drainage hose 12 is connected to the drainage device 11.

The drive device 7 is fixed to the bottom surface of the outer tank 4 by using a support plate 13 made of a steel plate. In the outer tub 4, the ps tube 1 for transmitting the pressure of the water in the outer tub 4 to the water level sensor 14.
An inlet for connecting 5 is provided.

On the upper portion of the outer frame 1, there is provided a top cover 16 made of synthetic resin, which has an input port 16a for loading and unloading laundry and an operation box 16b for accommodating electric and electronic parts such as a controller and a microcomputer 20. is there. Input port 16a
Is provided with a lid 17 made of synthetic resin. The top cover 16 is provided with a power switch 18 and a water supply valve 19 for supplying water during washing and rinsing.

FIG. 2 shows a block diagram of the control of the microcomputer 20.

An electric command from the fully automatic washing machine is input to the input side. This is a pulley 9a mainly attached to the power switch 18, the water level sensor 14, and the clutch device 10.
A rotation speed sensor 21 (not shown) or the like for measuring the rotation speed of is connected. On the output side, the motor 8 and the water supply valve 1
9, a solenoid 7a, a drainage device 11, a DC voltage generator 22 (not shown) attached to the center base, etc. are connected, and the washing machine is controlled by the input / output of the microcomputer 20 to perform a series of washing operations. .

FIG. 3 shows the suspension rod 2 and the vibration isolator 3 in detail.

The vibration isolator 3 comprises a spring 23 and a damping device 24.
The spring 23 is arranged at the lower part of the suspension rod 2, and the spring 23
The damping device 24 is arranged on the upper part of the above, and the outer tub 4 is received by the upper part of the damping device 24. The structure of the damping device 24 is such that an electrorheological fluid 26 is injected into a hollow cylindrical case 25, the hanging rod 2 is inserted through the center of the circle, and the hanging rod 2 is inserted. A packing 27 is added to the upper and lower parts so that the electrorheological fluid 26 in the case 25 does not flow out. Hanging rod 2 in case 25
A circular electrode plate 2a smaller than the inner diameter of the case 25 is added to the portion, and the lead wire connected to the circular electrode plate 2a is
The amplifier 2 is passed through between the fishing rod 2 and the hard protection tube 28.
9 is connected.

Further, an electrode 25a is added to the entire circumference of the case 25 in the circumferential direction and is connected to the amplifier 29. When an electric field is generated between the circular electrode plate 2a and the electrode 25a, the viscosity of the electrorheological fluid 26 between the circular electrode plate 2a and the electrode 25a increases, and the movement of the electrorheological fluid 26 in the case 25 is hindered. In addition, the circular electrode plate 2a added to the suspension rod 2 receives resistance, so that the damping ratio increases. When the electric field is cut off, the viscosity of the electrorheological fluid 26 decreases, the electrorheological fluid 26 can move freely, and the damping ratio decreases.

In FIG. 4, the circular electrode plate 2a of the damping device 24,
A block diagram for applying a voltage between the electrodes 25a to generate an electric field is shown.

A DC voltage generator 22 generates a DC voltage in response to a signal from the microcomputer 20, and the DC voltage generator 2
Amplifier 29 mounted on the center base in the same manner as 2
The voltage is amplified by (not shown), and the voltage is applied between the circular electrode plate 2a and the electrode 25a of the attenuator 24, and the voltage is applied to generate an electric field.

FIG. 5 shows the relationship between the electric field strength and the apparent viscosity of the electrorheological fluid 26. From the figure, it can be seen that the viscosity increases when an electric field is applied and decreases when it is turned off.

FIG. 6 is a block diagram showing the steps of the fully automatic washing course executed by this fully automatic washing machine. The steps of water supply, washing, drainage, dehydration, water supply, rinse, drainage and dehydration. It consists of process, water supply process, rinsing process, drainage process and final dehydration process.

FIG. 7 shows the relationship between the spinning speed and the spinning time during the spinning operation in the final spinning step. In the dehydration operation, intermittent on-off cycle is repeated at intervals of several seconds from the start to the steady rotation speed, the rotation speed is gradually increased, and when the steady rotation speed is reached, the set time operation is performed and the operation is completed.

Also in the dewatering process other than the final dewatering process in the fully automatic washing course, the intermittent dewatering is repeated by repeating the on-off at several seconds intervals from the start up to the steady rotation speed similarly to the final dewatering process, and the rotation speed is gradually increased. Up,
When the number of rotations reaches a steady value, the engine is operated for a set time which is relatively shorter than the final dehydration step, and the operation is completed.

In the above construction, the vibration occurring during the final dehydration step and the intermittent dehydration step of the fully automatic washing course, and the natural frequency of the vibration isolator 3 and the outer tub 4 supported by the vibration isolator 3 and the like. When the clothes in the dehydration tank 5 are distributed unevenly in rare cases through the resonance point where and coincide with each other, the vibration becomes large.

FIG. 8 shows the control of the damping device 24 in the dehydration process.

When the dehydration process is started, a DC voltage generator 22 generates a DC voltage in response to a signal from the microcomputer 20, the amplifier 29 amplifies the voltage, and the voltage between the circular electrode plate 2a and the electrode 25a of the attenuator 24 is increased. Generate an electric field in
Electrorheological fluid 26 between the circular electrode plate 2a and the electrode 25a
To increase the viscosity of the anti-vibration fluid 26 in the case 25, and to increase resistance of the circular electrode plate 2a attached to the suspension rod 2 to increase the damping ratio of the vibration isolator 3 to prevent vibration due to resonance. suppress.

If the damping ratio remains large after the normal rotation, the vibration transmissibility remains large, which affects vibration and noise.

Therefore, the pulley 9a is detected from the rotation speed sensor 21.
When the number of revolutions is detected and the set number of revolutions is reached after ω / ωo exceeds the position of √2 beyond the resonance point, the DC voltage generator 22 is stopped by the signal from the microcomputer 20, and the electrorheological fluid 26 To reduce the viscosity and allow the electrorheological fluid 26 to move freely, reduce the damping ratio of the vibration isolator 3 and the vibration transmissibility to reduce vibration,
Reduce noise.

[0030]

According to the present invention, in the dehydration process of a fully automatic washing machine, an electrorheological fluid is used as a damping device, and the damping ratio of a vibration isolator is made variable by turning on and off an electric field, thereby suppressing resonance and vibration. The noise can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a fully automatic washing machine.

FIG. 2 is an explanatory diagram of microcomputer control.

FIG. 3 is a sectional view of a vibration isolation device.

FIG. 4 is a block diagram of an electric field generating means.

FIG. 5 is a characteristic diagram of electric field strength-apparent viscosity of an electrorheological fluid.

FIG. 6 is an explanatory view of a process of a fully automatic washing course.

FIG. 7 is a characteristic diagram showing the relationship between the spin-drying speed and time.

FIG. 8 is a flowchart of control of the damping device.

FIG. 9 is a characteristic diagram showing the relationship between the vibration transmissibility and the frequency / external frequency of external force.

[Explanation of symbols]

2 ... Hanging rod, 2a ... Circular electrode plate, 3 ... Antivibration device, 4 ... Outer tank, 21 ... Rotation speed sensor, 22 ... DC voltage generator, 2
3 ... Spring, 24 ... Damping device, 25 ... Case, 25a ... Electrode, 26 ... Electrorheological fluid, 27 ... Packing, 28 ... Protective tube, 29 ... Amplifier.

Claims (3)

[Claims] 1. A fully automatic washing machine having an outer tub supported through a vibration isolator, wherein a liquid whose viscosity can be changed by a voltage or an electric field is used to make the damping ratio of the vibration isolator variable. Anti-vibration device for fully automatic washing machines. 2. A vibration isolation device for a fully automatic washing machine according to claim 1, wherein a rotation speed during a dehydration operation is detected and a damping ratio of the vibration isolation device is changed in accordance with a change in the dehydration rotation speed. 3. The vibration isolator according to claim 1, wherein the damping ratio of the vibration isolator is changed according to a set time.