JPH0332400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a direct current solenoid suitable for simultaneously operating a brake device, a drain valve, etc. in, for example, a washing machine.

Conventional structure and its problems Conventionally, in a single-tub centrifugal dehydrating washing machine, the first
It has a structure as shown in the figure, and in the figure,
1 is an outer tank for receiving washing water, and 2 is a washing/dehydration tank provided inside the outer tank 1. A pulsator 3 is arranged at the inner bottom, and a large number of small holes 4 for draining water are provided on the circumferential side wall. There is. Reference numeral 5 denotes a mechanical case, which has a mechanism for transmitting the drive of the motor 6 so as to rotate only the pulsator 3 during washing, and to rotate the washing and dehydrating tub 2 during dehydration. The motor 6 transmits drive to the mechanical case 5 through a belt 7 and a pulley 8. 9 is a drain valve connected to the inner bottom of outer tank 1; 10
1 is a brake arm, 11 is a solenoid that pulls the drain valve 9 and the brake arm 10, 12 is a support plate, on which the outer tank 1, motor 6, mechanical case 5, etc. are arranged, and is suspended from the outer tank 14 by a rod 13. ing. 15 is a balancer provided at the top of the washing and dewatering tank, and 16 is a drain hose.

Next, the operation of the solenoid 11 will be explained using FIG. 2. The drain valve 9 is connected to the drain valve 9 via a connecting member 17. Inside the mechanical case 5, there is a brake wheel 18 and a brake band 19.
The brake band 19 can be press-contacted to and detached from the brake wheel 18, and performs a braking action. The rotation of the brake wheel 18 is transmitted as the rotation of the washing and dehydrating tub 2. That is,
When the brake band 19 is pressed, the brake wheel 18 does not rotate, and the washing and dehydrating tub 2 also does not rotate.

During washing, the solenoid 11 is not energized, so the drain valve 9 is closed by the force of the built-in spring and brake spring 20. Further, since the brake wheel 18 is pressed against the brake band 19 and does not rotate, the washing and dehydrating tub 2 does not rotate.
Washing can be done by rotating only the pulsator 3.

During drainage and dehydration, the solenoid 11 is energized and the plunger 11-a of the solenoid 11 is attracted. The connecting member 17 connected thereto will move in the direction of the arrow. Therefore, the drain valve 9 opens, the brake arm 10 rotates, and the brake band 19 separates from the brake wheel 18, resulting in a dewatering operation.

As described above, the solenoid 11 is used to open and close the brake device and the drain valve 9 of the washing and dewatering tank 2.

Here, there are two types of solenoids: AC solenoids and DC solenoids.
As shown in the figure, a coil 11-a that generates a magnetic field,
It is composed of a plunger 11-b that is attracted and moves, and a fixed iron core 11-c that is fixed. And their characteristics can be listed as follows.

In the AC solenoid, the reactance of the coil 11-a is extremely large compared to the resistance, so the current changes depending on the stroke. At this time, the larger the stroke, the larger the current flows. on the other hand,
In a DC solenoid, the steady current is determined only by the DC resistance of the coil 11-a, regardless of the stroke. Also, the attractive force is determined by the magnetomotive force, which is given by the product of the current and the winding. Therefore, the AC solenoid can handle a large load with a larger stroke than the DC solenoid, relative to the amount of copper in the coil 11-a. Therefore, in single-tub centrifugal dehydrating washing machines, it is common to use an AC solenoid.

However, in an AC solenoid, the current value changes depending on the stroke, so the plunger 11
- If voltage is applied for a long time without being completely absorbed, there is a risk of burnout. In addition, since alternating current is used, beats are likely to occur when there is a slight gap. As can be seen from these facts, in the case of an AC solenoid, it is necessary to completely attract the plunger 11-b and the fixed core 11-c. It is impossible to use cushioning material.

Furthermore, the AC solenoid is better for plunger 1.
The acceleration of 1-b is large and the impact is large. Therefore, when an AC solenoid is used, a large impact sound is always generated, resulting in noise. DC solenoids do not have the above-mentioned problems and have a quiet structure, so DC solenoids are more advantageous in terms of performance.

However, at present, the noise reduction structure of DC solenoids cannot be said to be perfect. In other words, if a cushioning material is provided between the plunger and the fixed core, the suction force and adhesion holding force will be significantly reduced.
In order to prevent such a decrease, it is necessary to increase the wire area of the coil. Moreover, this inevitably led to an increase in costs.

OBJECTS OF THE INVENTION The present invention solves these conventional problems and provides a direct current solenoid that can reliably have a silent structure at a low price comparable to or lower than that of an alternating current solenoid.

Structure of the Invention In order to achieve the above-mentioned object, the present invention connects a plunger that sucks a load and a fixed iron core that comes into contact during suction to the solenoid outer frame via a buffer member.
Due to the slidable engagement, the collision noise when the plunger is attracted is eliminated without reducing the suction force or the close holding force.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 5, reference numeral 21 denotes a connecting member for connecting and connecting the plunger 22 made of a magnetic material and a load portion such as the drain valve 9, and is connected to the plunger 22 by a fixing pin 23. Reference numeral 24 denotes a solenoid outer frame made of a magnetic material, which includes a bobbin 25, a coil 26 wound around the outer periphery of the bobbin 25, and an external power terminal 27 fixed inside the coil 26. Reference numeral 28 denotes a fixed core that comes into close contact with the plunger 22 during suction, and when the plunger 22 is in close contact with the plunger 22, the concave portion 22-a on the end face of the plunger 22 and the convex portion 2 of the fixed core 28
8-a are in close contact with each other. And fixed core 2
8 on the side opposite to the plunger 22 is slidably engaged with the solenoid outer frame 24 via a buffer member 31 having a buffer effect such as rubber or a spring.
Furthermore, between the tip pressing part 21-a of the connecting member 21 and the suction plate 30 made of a magnetic material, there is an adsorption auxiliary plate 29 with a buffering effect, so that the suction plate 30 completely adheres to the solenoid outer frame 24 during suction. It is configured to do so.

In the DC solenoid having the above configuration, when the power is turned on, a magnetomotive force is generated by the action of the current flowing through the coil 26, and the plunger 22, which has been pulled toward the load side, is attracted toward the fixed iron core 28 side. Then, as the plunger approaches the fixed iron core 28, the suction force becomes stronger, so it is accelerated, and the plunger 22 collides with the fixed iron core 28 with considerable force.
However, a buffer member 31 is provided on the back surface of the fixed iron core 28, which softens the shock during suction and suppresses transmission of the shock to the solenoid outer frame 24. Therefore, the sound caused by the collision is suppressed, and no resonance occurs in the solenoid outer frame 24. Furthermore, since the fixed core 28 is slidably engaged with the solenoid outer frame 24, the presence of the buffer member 31 does not cause problems such as inability to secure a magnetic circuit for attracting the plunger 22. do not have.

In other words, the generated magnetism is transmitted to the solenoid outer frame 24.
The magnetic material passes through the suction plate 30 to the plunger 22, and then to the solenoid outer frame 24 via the fixed iron core 28, forming a complete magnetic sealed circuit, so that there is no loss of efficiency.

The material for the buffer member 31 is generally rubber, which has a high sound-absorbing effect, but the use of an iron-based spring, which is a magnetic material, is effective in forming a magnetically sealed circuit. Furthermore, if the rubber base material is mixed with magnetic materials such as iron powder,
Magnetism can be secured without damaging elasticity, so
This can prevent the solenoid's suction power from decreasing.

Effects of the Invention As is clear from the above embodiments, the DC solenoid of the present invention can eliminate the impact noise that conventionally occurs during suction without impairing the suction force. On the other hand, since there is no particular difference from the conventional method, it can be obtained at a low cost.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a conventional washing machine with a dehydrating function (single tank type), Fig. 2 is a cutaway plan view of the main parts near the solenoid, Fig. 3 is a perspective view of the appearance of a conventional DC solenoid, and Fig. 4 The figure is a sectional view of the same solenoid, and FIG. 5 is a sectional view of a DC solenoid in an embodiment of the present invention. 11... Solenoid, 22... Plunger,
24... Solenoid outer frame, 28... Fixed iron core, 3
1...Buffer member.

Claims (1)

[Claims] 1. A fixed iron core that comes into contact with the plunger during suction,
A DC solenoid that is slidably engaged with a solenoid outer frame made of a magnetic material via a buffer member. 2. The DC solenoid according to claim 1, wherein the buffer body is made of an elastic body such as rubber mixed with a magnetic material. 3. The DC solenoid according to claim 1, wherein the buffer body is a spring made of iron.