JPH0453208A - Electromagnet - Google Patents

Abstract

PURPOSE:To improve positional accuracy in movement of a movable core by a method wherein the guidance of advancing and retreating movements of a movable core is conducted only by the non-magnetic member of a pipe. CONSTITUTION:In order to prevent a movable core 10 from coming into contact with the part 24 of a magnetic member, the gap between the inner circumferential surface of the part 24 of the magnetic member of a pipe 1 and the outer circumferential surface of the part opposing to the movable core 10 is made larger than the gap between the inner circumferential surface of the part 25 of the non-magnetic member of the pipe 1 and the other circumferential surface of the part opposing to the movable core 10. The movable core 10 moves toward a fixed core 2 when magnetic force reaches the movable core by the application of a current to a coil. The movable core 10 is guided only by the part 25 of the non-magnetic member of the pipe, and the core 10 does not come in contact with the part 24 of the magnetic member. Accordingly, the sliding resistance of the pipe 10 and the movable core 10 is small, and the positional accuracy of the shifting of the movable core 10 can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to electromagnets used to operate valves and other devices.

[Conventional technology]

A conventional electromagnet has a pipe for guiding a movable core, a fixed core is disposed at one end of the pipe, a yoke is disposed at the outer circumference of the other end of the pipe, and - around the pipe. A ring-shaped coil is disposed within the pipe, and a movable core is provided in the pipe so as to be able to move forward and backward.The pipe is formed of two different members: a magnetic member on the yoke side and a non-magnetic member on the fixed core side. The movable parts of the valve and other devices are moved by the movement of the movable iron core.

[Problems to be solved by the invention]

By the way, for example, in a proportional control valve used in a precision machine, it is necessary to control the opening degree of the valve with high precision.

For this reason, in an electromagnet for operating such a proportional control valve, it is necessary to move the movable iron core with extremely high positional accuracy. However, in the above-mentioned conventional electromagnet, the entire L pipe guides the movable core in its forward and backward movement, so a large magnetic attraction force is generated at the contact area between the movable core and the magnetic member. The sliding resistance there increases, and as a result, the hysteresis of the movable core becomes large as shown in Fig. 6.7, resulting in a problem that the positional accuracy of the movable core is low.

The present invention has been made in order to solve the problems (technical problems) of the prior art described above. The object of the present invention is to provide an electromagnet that can perform this with extremely high positional accuracy.

[Means for solving the problem] In order to achieve the above object, the electromagnet in the present invention has the following features:
It has a pipe for guiding the movable core, a fixed core is arranged at one end of the pipe, a yoke is arranged at the outer circumferential side of the other end of the pipe, and a ring-shaped coil is arranged around the pipe. - A movable iron core moves forward and backward inside the pipe. 1
The pipe is formed of two different members: a magnetic member on the yoke side and a non-magnetic member on the fixed core side, and the inner diameter of the non-magnetic member portion is the same as that of the movable core. Guide the advance and retreat of
In an electromagnet formed to have an inner diameter close to the outer diameter of the J moving iron core, the inner circumferential surface of the magnetic member portion of the pipe is prevented from contacting the moving iron core with the magnetic member portion of the pipe. The gap between the outer circumferential surface of the portion of the movable iron core that is opposite thereto, and the inner circumferential surface of the non-magnetic member portion of the pipe and the outer circumferential surface of the portion of the movable iron core that is opposite thereto. 4), which is larger than the gap.

[Effect]

When a magnetic force is applied to the movable core by energizing the coil, the movable core moves toward the fixed core. During this movement, the movable core is guided only by the non-magnetic part of the pipe and does not come into contact with the magnetic part. Therefore, the sliding resistance between the pipe and the movable iron core is small. This small sliding resistance increases the movement of the movable iron core from position to position.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, the electromagnet A for a solenoid valve of this example is attached to a well-known valve body (=JlJ) to form a proportional control solenoid valve. The electromagnet A consists of an iron core assembly B, an annular coil assembly C disposed around the core assembly in a manner that it can be freely inserted and removed, and a fixture for fixing the latter to the former.

Below - the above core assembly B will be explained. J is a pipe for guiding the movable core, and 2 is a fixed core connected (for example, welded) to one end of the pipe 1, and is made of a magnetic material such as pure iron or low carbon steel. Reference numeral 3 denotes a mounting portion formed and provided on the fixed iron core 2, and a male thread 4 for screwing into the valve body is formed around the mounting portion. 5 indicates a through hole, and a valve bin 6
is inserted through it so that it can move forward and backward. 7 is a closed body connected (for example, welded) to the other end of the pipe 1, and is equipped with a bushing pin 8 for manual operation that can be moved forward and backward, and a male thread 9 for screwing a fixing device is formed on the outer peripheral surface. There is.

Reference numeral 10 denotes a movable iron core that is provided inside the pipe so as to be able to move forward and backward, and is made of a magnetic material such as pure iron or low carbon steel in the shape of a round bar. is formed.

Next, the coil assembly C will be explained. Reference numeral 13 denotes a coil, which is constructed by winding 15 on a bobbin 14. Reference numeral 16 denotes a yoke disposed on the outer circumferential side of the other end of the pipe 1, which is made of a magnetic material such as pure iron or low carbon steel. It is designed to connect properly.

17! :i: A molded body that integrates the coil 13 and the yoke] 6, and also serves as a case, and is made of well-known thermosetting or thermoplastic casting resin with high heat resistance. Additionally, glass powder may be mixed in to increase mechanical strength. The lead wire of the coil 13 is connected to a plug whose base part is embedded in the molded body 17.

Next, the fixing tool I] is formed in an annular shape, has a female thread 21 formed therein which is screwed into the male thread 9, and has a presser foot #22 for holding down the coil terminal C. .

Next, the pipe 1 will be explained in detail based on FIG. That is, the portion 24 on the side of the yoke 16 is made of a magnetic material, for example, stainless steel, and serves as a magnetic portion, and the portion 25 on the side of the 21st column 2 is made of a non-magnetic portion 44, e.g.
゛It is made of non-magnetic stainless steel and serves as a non-magnetic part.

Both parts 24 and 25 are integrated by joining (for example, welding) one end of each at a joint part 26, and the magnetic part 24 (t
The H end is joined (for example, welded) to the closure body 7, and the non-magnetic part 2
The other end of 5 is joined (for example, welded) to the fixed iron core 2 at a joint 27. Note that the magnetic part and the non-0171 part may be originally formed integrally from two materials and then heat-treated to separate the properties into magnetic and non-magnetic, thereby forming C. The inner diameter of the non-well 14 part 25 is
In order to stably guide the movable iron core 10, the size approximates the diameter of the groove, for example, the inner peripheral surface of the non-magnetic part 25 and the movable iron core 10.
Gap G between the outer circumferential surface of the opposing part
li (In the present Mei Ia, the dimensions of the above-mentioned gap are indicated by the difference in diameter) are formed so that they are 10 to 201 Jm. The length 2 of the portion of the non-magnetic portion 25 that guides the movable core 10 is preferably about 60% or more of the length 1, 1 of the movable core 10 so that the movable core 10 can be guided stably. On the other hand, the inner diameter of the magnetic part 24 is made larger than the inner diameter of the non-magnetic part 25 so that the movable core 10 does not come into contact with the inner circumferential surface of the magnetic part 24 during the entire process of advancing and retracting the movable core 10. The gap G2 between the inner circumferential surface and the outer circumferential surface of the opposing portion of the movable iron core 10 is larger than the gap G1 in the magnetic part 24 (for example, 60 to 7
Q, um). Note that the non-magnetic portion 25 may include a portion formed at the upper portion thereof to have the same inner diameter as the magnetic portion 24 described above. Further, in FIG. 2, reference numeral 29 is a spacer for preventing the movable core 2 from being attracted to the fixed core 2 xL, and is made of a non-magnetic material.

Next, the operation of the electromagnet having configuration 1- is as follows.

When the winding 15 of the coil is energized through the plug I8, the magnetic flux generated thereby circulates through the coke 16, the movable iron core IO1, the fixed iron core 2, and the yoke shown in FIG. As a result, movable iron core 10C No. 2 fixed iron core 2
The attraction force towards the This suction force causes it to move toward the fixed iron core 2 side. In this case of non-hyperactivity, the movable iron core 10 is non-magnetic (only 25 years old,
I was guided by "l-" and looked at it! K? , R24c does not come into contact. At the same time, the sliding resistance of the movable iron core 10 for Byfu River (
Yo 11\sai. As a result, the movable iron core 10 reliably moves to a position corresponding to the current value of the winding 15 of the coil /l/+2 current with high accuracy. -The movable core 10 is moved by the bin 6.
ζ is transmitted to the spool of the valve body, for example, and causes it to move. On the other hand, when the energization to the S wire 15 of the ':1 line is cut off, the magnetic flux disappears, so that the movable iron core 101 loses its attractive force. In this case, for example, if the spool is returned to the neutral position by a well-known return spring disposed within the valve body, its return causes The movable iron core 10 is also returned.

Next, FIG. 3 shows the electromagnet A (the outer diameter of the movable core 10 is 12 mm).
．． 47mm, length 22mm, gap G1 1.0
．． +Jm, gap G2 is 60μm example) Stroke:
This shows an example of the characteristics of horizontal attraction force, and FIG. 4 shows an example of the characteristics of current to the electromagnet: horizontal attraction force. These figures and Figure 6.7, which shows similar characteristics for an electromagnet with a conventional configuration that does not have the difference in gap GIG2 as described above, are shown in Figure 6.7. In the electromagnet A of this example, which has the above-mentioned gaps Gl and G2, the hysteresis H4 is much smaller than the hysteresis H1'~114'' of the conventional one. In the characteristic diagram of stroke O
0 indicates the position closest to the fixed core 2.

Next, FIG. 5 shows a different embodiment of the present application, in which a movable core 1. By forming the outer diameter of the portion 32 facing the magnetic portion 24e in the pipe le smaller than the outside diameter of the portion 31 facing the non-magnetic portion 25e in the pipe le, the inner peripheral surface of the magnetic portion 24e and the movable iron core 10e are The gap between the opposite circumferential surface of the portion 32 is
5e shows an example in which the gap is larger than the gap between the inner circumferential surface of the movable iron core 10e and the outer circumferential surface of the portion 31 that is paired therewith in the movable iron core 10e.

It should be noted that parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

〔Effect of the invention〕

As described above, in the present invention, by energizing the coil 13, it is possible to exert a magnetic force on the movable core 10 and move it, and of course, this movement can be used, for example, to operate a valve. When moving the movable core 10 as described above, since the movable core 10 is guided only by the non-magnetic member portion 25 of the pipe 1, the hysteresis of the movable core 10 is shown, for example, in FIG. 3.4. As such, it is smaller than the conventional example shown in FIG. 6.7, and has the effect that the movable core 10 can be moved with extremely high positional accuracy.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and Fig. 1 is a longitudinal cross-sectional view of an electromagnet, Fig. 2 is an enlarged view of the main part of Fig. 1, and Fig. 3.4 is a graph showing the characteristics of the electromagnet shown in Fig. 1. , FIG. 5 is an enlarged view of the main part showing a different embodiment, and FIG. 6.7 is a graph showing the characteristics of a conventional electromagnet. 1... Pipe, 2... Fixed iron core, 10. Movable iron core,
16...Yoke, 24...Magnetic portion, 25.Nonmagnetic portion. ] 2 P4-gi E ku

Claims (1)

[Claims] It has a pipe for guiding a movable core, a fixed core is arranged at one end of the pipe, a yoke is arranged at the outer circumferential side of the other end of the pipe, and an annular coil is arranged around the pipe. A movable core is provided in the pipe so as to be able to move forward and backward, and the pipe is formed of two different members: a magnetic member on the yoke side and a non-magnetic member on the fixed core side. The inner diameter of the magnetic member portion is formed to have an inner diameter approximate to the outer diameter of the movable core so as to guide the advance and retreat of the movable core.In the electromagnet, contact between the movable core and the magnetic member portion of the pipe is made In order to prevent this, the gap between the inner circumferential surface of the magnetic member portion of the pipe and the outer circumferential surface of the opposing portion of the movable core is set so that the gap between the inner circumferential surface of the non-magnetic member portion of the pipe and the An electromagnet characterized by having a gap larger than the gap between the movable core and the outer peripheral surface of the opposing portion.