JP2966122B2 - Drum type washing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration means for a drum type washing machine having a horizontal rotating shaft.

[0002]

2. Description of the Related Art A drum type washing machine which performs washing, dehydration and drying inside a drum having a horizontal rotating shaft supports the drum with a structure as shown in FIG. 5 , for example.

That is, a washing tub 2 in which a drum is rotatably housed is suspended by a coil spring 3 inside a case 1 placed on a floor 10, while a damper 11 having one end connected to a lower portion of the case 1. The drum 4 is supported from below.

[0004] This is to prevent the laundry receiving tub 2 from vibrating greatly when the laundry 12 is not uniformly pressed against the inner periphery of the drum 4 during dehydration and the rotation of the drum becomes unbalanced.

[0005] A motor 7 for rotating the drum is attached to the lower part of the washing tub 2 and transmits a rotating force to the drum 4 via a belt.

[0006]

The mechanism for absorbing vibration of the drum in this case is shown in the model of FIG. The equation of motion of this model is as shown in Equation 1.

[0007]

(Equation 1)

Further, when the vibration transmissibility on the floor 10 is obtained from this equation, a graph shown in FIG. 7 is obtained. In the graph, C is an attenuation coefficient, C = 0 is a case where the damper 11 is not used, C = ∽ is a case where the washing tub 2 is rigidly connected to the case ₁ , and C = C ₁ is a washing tub with the damper 11. 2 is shown in FIG .

As is apparent from this graph, the resonance is suppressed by the damping effect of the damper 11 in the low-speed rotation region near the resonance point fa. However, in the high-speed rotation region above fb, the use of the damper 11 is reversed. The vibration transmissibility is high.

However, in a general drum type washing machine, the rotation speed of the drum in the dehydration stage is changed from a low speed to a resonance point fa.
In most cases, the damper 11 rises after passing through and reaches a steady rotation in a high-speed rotation range exceeding fb. Therefore, the damper 11 is required so that the washing tub 2 does not vibrate greatly at the resonance point fa. I had to be prepared for the increase in vibration to some extent.

The present invention has been made to solve the above problems, and has as its object to efficiently suppress the vibration of a drum type washing machine from a low rotation speed to a high rotation speed in a wide range.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a washing tub having a rotating drum housed therein is provided inside a case, and a washing tub is provided inside the case.
Hanging spring and low-speed rotation near the drum resonance point
In a drum type washing machine supported by a damper that attenuates vibration in the area, a damping force adjustment mechanism that changes the damping force by exciting a solenoid is provided in the damper, and a resonance point is provided.
As described above, the fb rotation speed that does not exceed the steady rotation speed during dehydration is set.
Power supply to the motor that rotates the drum during spin-drying.
Where the rotation speed of the drum rises to fb rotation speed
Set a fixed time with a timer and actuate damping force by timer operation
To the motor that rotates the drum
After stopping the power supply, the drum rotation speed drops to fb rotation speed.
Preset time is set by a timer and attenuated by timer operation
Means were provided for interrupting the supply of the exciting current to the solenoid so as to exert a force .

[0013]

[Function] While the damping force generated by the damper is changed in accordance with the excitation of the solenoid, the exciting current is intermittently controlled by the timer, so that the optimum damping force corresponding to the rotating state of the drum can be easily obtained. The vibration of the drum can be suppressed in a wide range.

[0014]

The embodiments of the present invention will be described with reference to EXAMPLES 1 to 4.

[0015] The damper 1 shown here in FIGS. 5 and 6
1 is replaced by an electromagnetic damper 5 shown in FIG.

The electromagnetic damper 5 has a piston 21 slidably housed inside a cylinder 20 and a piston rod 22 fixed to the piston 21 slidably projecting from the cylinder 20 in the axial direction. A bracket 36 for attaching the electromagnetic damper 5 to the washing tub and the case is attached to each base end of the piston rod 22 and the piston rod 22.

The outside of the cylinder 20 is covered with an outer shell 23, and an oil reservoir 24 for storing the hydraulic oil flowing out of the cylinder 20 is provided in these annular gaps.

The inside of the cylinder 20 is defined by a piston 21 into an oil chamber 25 on the piston rod 22 side and an oil chamber 26 on the opposite side, and hydraulic oil flows through the piston 21 only from the oil chamber 26 to the oil chamber 25. A check valve 27 is provided. A check valve 28 is provided at the bottom of the cylinder 20 to allow only oil to flow from the oil reservoir 24 to the oil chamber 26.

A valve guide 30 having a port 29 formed at the tip of the cylinder 20 for communicating the oil chamber 25 with the oil reservoir 24.
Is fixed, and a valve 31 that opens and closes the port 29 is fitted slidably in the axial direction on the outer periphery of the valve guide 30.

A solenoid 32 for driving the valve 31 is attached to the inside of the outer shell 23 via a holder 33 so as to surround the outside of the piston rod 22.

The holder 33 supports a stopper 34 for regulating the displacement of the valve 31 and one end of a spring 35 for urging the valve 31 in the closing direction.

The valve 31 is held by the spring 35 in a position where the port 29 is closed. The solenoid 32 is excited by a current supplied from the outside through a wiring (not shown), and opens the port 29 by attracting the valve 31 made of a magnetic material to the stopper 34 against the spring 35.

On the other hand, a controller 40 shown in FIG. 2 is provided inside the case of the washing machine to control the energization of the solenoid 32.

The controller 40 has a timer which is linked to the switch 6 of the motor for driving the drum to rotate. As shown in FIG. 3, a predetermined time T _{1 has} elapsed since the switch 6 was turned on.
, The energization of the solenoid 32 is started.

Further, to cut off the power supply to the solenoid 32 when the switch 6 has passed the predetermined time T ₂ from off.

[0026] Incidentally, T ₁ is the time from the start of motor rotation until the rotation speed of the drum reaches fb in FIG 7, T ₂
Is the time from when the power supply to the motor is stopped in the steady rotation state of the drum to when the rotation of the drum falls to fb, and is set based on actual measurement.

The other structure is the same as that of the conventional example.
Next, the operation will be described.

In this electromagnetic damper 5, the piston 21
Slides inside the cylinder 20, the piston 21
The flow of hydraulic oil from the oil chamber 25 to the oil reservoir 24 is formed irrespective of the sliding direction. This flow of hydraulic oil flows through the port 29 without resistance due to the magnetic force of the excited solenoid 32 when the valve 31 opens the port 29. However, when the solenoid 32 is not excited, the valve 31 closes the port 29. In this case, the hydraulic oil cannot flow except for leaking from the gap between the valve 31 and the valve guide 30, and as a result, a large damping force as shown in FIG. 4 is generated.

On the other hand, the controller 40 starts the timer when the switch 6 of the motor for rotating the drum is turned on to start the energization of the solenoid 32 after a time T _1. Similarly to the switch 6 and to cut off the energization to the solenoid 32 after a turn off when the time T _2.

As a result, the electromagnetic damper 5 has a hard damping force characteristic when the rotation speed of the drum is less than fb, and has a soft damping force characteristic when the rotation speed is more than fb. As a result, in a low rotation region around the resonance point fa, resonance is prevented by a large damping coefficient C, and in a high rotation region including a steady rotation state, transmission of vibration of the drum is interrupted by a damping coefficient close to zero. A favorable vibration damping effect can be obtained over the entire speed range.

[0031]

[0032]

[0033]

As described above, according to the present invention, the washing tub for accommodating the drum of the drum type washing machine is supported by the electromagnetic damper which varies the damping force according to the rotation speed of the drum. The vibration damping of the washing machine can be enhanced over a wide range from the high speed range to the high speed range.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic damper showing an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a method of controlling an electromagnetic damper.

FIG. 3 is a graph illustrating a relationship between a change in the number of revolutions of a motor and energization of a solenoid.

FIG. 4 is a graph showing damping force characteristics of an electromagnetic damper.

FIG. 5 is a schematic structural view of a drum type washing machine showing a conventional example.
You.

FIG. 6 is an explanatory diagram of a one-degree-of-freedom system vibration absorption model.

FIG. 7 is a graph showing a vibration transmissibility.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-29674 (JP, U) JP-A-2-112504 (JP, U) (58) Fields surveyed (Int.Cl. ⁶ , DB name) D06F 37/22 D06F 25/00

Claims (1)

(57) [Claims] 1. A spring for suspending a laundry receiving tub having a rotating drum housed inside the case and the laundry receiving tub inside the case,
In a drum-type washing machine supported by a damper that attenuates vibration in a low-speed rotation region near a drum resonance point, a damping force adjustment mechanism that changes a damping force by exciting a solenoid is provided in the damper, and the resonance point is higher than the resonance point. For steady rotation during dehydration
Set the fb rotation speed not to exceed the number, and rotate the drum during dehydration.
After turning on the motor to rotate, start rotating the drum.
A predetermined time during which the number increases to the fb rotation speed is set by a timer,
Do not apply damping force by timer operation,
Stop supplying power to the motor that rotates the ram, and then
The timer sets the predetermined time during which the system rotation speed falls to fb rotation speed.
And a means for interrupting the supply of the exciting current to the solenoid so that the damping force is activated by a timer operation .