JPS5814590B2 - solenoid valve - Google Patents

Description

[Detailed description of the invention] The present invention relates to a solenoid valve.

Conventionally, as seen in Utility Model Application Publication No. 50-50429,
2. Description of the Related Art An electromagnetic valve is known in which a movable core is slidably provided in a hollow part of a resin bobbin provided in a case, and a valve fixed to the movable core is driven to control a fluid passage.

First, the structure and operation of this solenoid valve will be explained based on FIG. It is provided.

Then, the coil 5 is
is excited, the metal magnetic plate 6, the case 1,
A magnetic flux circuit 8 is formed by the fixed iron core 7 and the movable iron core 3, whereby when energized, the movable iron core 3 slides so as to overcome the spring force of the presser spring 9 and project the needle valve 10 to the outside by a predetermined stroke length. On the other hand, when the electrical signal to the terminal 4 is cut off, the movable core 3 is pulled in by the push spring 9 for a predetermined distance.

In such a solenoid valve, a pair of collar portions 12A and 12B for winding five coils are provided on the outer periphery of the bobbin 2 integrally with the bobbin 2 due to its structure.

However, among these collar portions 12A and 12B, collar portion 1
2B is included in the sliding range of the movable iron core 3, an abnormal expansion part 13 is formed inside the bobbin 2 near the collar part 12B as shown in FIG. 2 due to temperature rise due to long-term operation of the solenoid valve. There is.

The reason why this abnormally expanded portion 13 is formed has not been elucidated in detail, but it is thought that the amount of resin in the vicinity of the collar portion 12B is large, and therefore the resin in the vicinity of the collar portion 12B expands abnormally.

When this abnormal expansion part 13 is formed, the bobbin 2
If the gap Δd between the inner circumferential diameter of the movable iron core 3 and the outer circumferential diameter of the movable iron core 3 is small, there is a phenomenon in which the two contact each other and cause malfunction.

If the gap Δd is increased over the entire length of the movable core 3 in order to eliminate the influence of the abnormally expanded portion 13, the resistance of the magnetic flux circuit 8 increases, resulting in drawbacks such as a decrease in attractive force.

An object of the present invention is to enable a movable iron core to slide smoothly even if an abnormally expanded portion of resin occurs in the collar of a resin bobbin.

In order to achieve this object, in the present invention, an outer peripheral groove having a width of a predetermined length is provided on the outer periphery of the movable core, and when the movable core moves according to the state where the coil is demagnetized to the excited state, The flange formed near the movable core is always positioned within the width of the outer circumferential groove.

According to this, when the movable core is displaced from a state in which current flows to the coil to a state in which current to the coil is cut off,
The formation position of the collar portion of the bobbin is always located within the width of the outer circumferential groove of the movable iron core.

Therefore, the abnormal expansion portion generated at the collar of the bobbin and the movable core do not come into contact with each other, allowing the movable core to operate smoothly.

At this time, the portions of the movable core other than the outer circumferential groove are similar to the gap between the movable core and the inner circumferential portion of the bobbin in the prior art, so that the suction force does not decrease so much.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of a solenoid valve according to the present invention will be described with reference to the accompanying drawings.

In explaining the solenoid valve of the present invention, the shape and structure of the main body are as follows:
Since the structure is not different from the conventional solenoid valve shown in Figure 1,
The explanation of that part will be omitted.

As shown in FIGS. 3 and 4, the solenoid valve according to the present invention has an outer circumferential groove 16 having a predetermined width l on the outer circumference of the movable iron core 15 facing the collar portion 12B formed on the outer circumference of the bobbin 2.
is formed.

Then, the movable iron core 1 in which such an outer circumferential groove 16 is formed
5 is such that when the movable core 15 is displaced from a state in which current flows through the coil 5 to a state in which the current to the coil 5 is cut off, the formation position of the flange portion 12B is always in the outer circumferential groove 16 of the movable core 15. It is driven to be located within the width l.

Here, when the movable core is displaced from a state in which current flows through the coil 5 to a state in which the current flows to the coil 5 is cut off, the formation position of the flange portion 12B is always within the width of the outer circumferential groove 16 of the movable core 15. The reason why it is located at 12B is that
This is because the part expands the most, and the brim part 12 always expands the most.
This is because if the portion B is within the width of the outer circumferential groove 16, the movable core 15 can be operated without coming into contact with the abnormally expanded portion 13.

In this way, in the present invention, since the outer circumferential groove 16 having a width of a predetermined length is provided on the outer periphery of the movable core 15, the abnormal expansion portion 13 does not interfere with the movable core in any way, and therefore the movable core 15 can operate smoothly. Moreover, since the diameter of the groove other than the outer circumferential groove 16 is the same as that of the conventional one, the suction force does not decrease so much.

Here, as an example of the present invention, the outer peripheral groove 16 provided in the movable iron core 15 has a width l of 24 mm or more, a depth H of 0.15 mm or more, and 1. 5m
m or less.

In this way, the dimensions and shape of the outer circumferential groove 16 of the movable core 15 were determined based on the fact that in many cases, the specific dimensions of the abnormally expanded portion 13 of the bobbin 2 made of various resins were experimentally determined to have a maximum height of 0.15 m.
m, its total length is 20 mm, and the sliding stroke length of the movable iron core 15 is generally 4.0 mm or less.

Therefore, in order to eliminate all the effects of the abnormal expansion part 13, it is ideal to have a depth of 0.15 m on the outer periphery of the movable core 15.
By providing the outer circumferential groove 16 with a width of about 24 mm or more and a width of about 24 mm, even if the temperature of the coil 5 rises, the movable core 15 will not come into contact with all of the abnormal expansion part 13 of the resin bobbin 2 and will operate smoothly. be able to.

On the other hand, from FIG. 5, even if the outer circumferential groove 16 is provided, the predetermined value 14
In order to obtain the above suction force, the outer circumferential groove 1 of the movable iron core 15 must be
6, it can be seen that the depth is preferably 1.5 mm or less.

Therefore, if an outer circumferential groove 16 with a width of about 24 mm and a depth of about 0.15 mm to 1.5 mm is formed at a predetermined outer circumferential portion of the movable iron core 15, this outer circumferential groove 16 will be affected by the abnormal expansion part 13 of the resin bobbin 2. The movable iron core 15 can be smoothly operated without reducing the required suction force.

In the description of one embodiment of the present invention, a movable iron core in which a circumferential outer groove is formed is shown, but as shown in FIG. Abnormal expansion part 13 of bobbin 2 whose movable iron core is made of resin with outer peripheral groove
You may try not to come into contact with it.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view showing a conventional solenoid valve, Figure 2 is a partially enlarged view of the conventional movable core and the collar of the resin bobbin, and Figure 3 is a vertical cross-sectional view showing a conventional solenoid valve.
The figure is a partially enlarged cross-sectional view of the movable iron core and flange part incorporated in a solenoid valve according to an embodiment of the present invention, FIG. 4 is a perspective view of the movable iron core of FIG. 3, and FIG. FIG. 6 is a diagram showing a characteristic of attraction force with respect to the notch groove depth dimension of the movable core from the circumference, and FIG. 6 is a diagram showing a modification of the movable core. 1... Case, 2... Resin bobbin, 3, 15... Moving iron core, 5... Coil, 6... Plate. , 7... Fixed iron core, 8... Magnetic flux circuit, 10... Needle valve, 1
2A, 12B...Brim part, 16...Outer circumferential groove.

Claims (1)

[Claims] 1. A bobbin made of resin having a hollow part, first and second collar parts integrally formed with the bobbin on the outer periphery of the bobbin, and a ring on the outer periphery of the bobbin between the first and second collar parts. a wound coil, a fixed core that extends beyond the position where the first flange is formed into the hollow portion of the bobbin and is housed and fixed in the hollow portion; In a solenoid valve comprising a movable core disposed near a position where a second flange is formed and having a valve body at one end, the movable core moves according to the state of the coil from a demagnetized state to an energized state. In the electromagnetic valve, an outer peripheral groove is formed on the outer periphery of the movable iron core so as to always include the formation position of the second flange portion.