JP2542966B2 - DC electromagnet - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a DC electromagnet used in an industrial hydraulic solenoid valve or the like.

(Prior Art) Conventionally, a DC electromagnet has been widely used for switching spools of a hydraulic solenoid directional control valve, but its structure is generally described in, for example, JP-A-62-82412. there were. As shown in FIG. 4, a thin guide tube A made of a non-magnetic material, which is provided inside the solenoid coil and has one end widened in a conical shape, is provided with sealing materials D and E between a stator B and an upper cover C. And the plunger F forms an axially movable cylindrical oil chamber. The order of assembling is to fix the coil case G on the plate portion L of the stator B by brazing the periphery of the coil case G at the corners H, and in the coil case G, the solenoid parts, the yoke J, and the upper cover C.
After mounting, the upper end K of the coil case G is caulked and joined to the outer periphery of the upper lid C.

However, in the above-described conventional electromagnet, it is necessary to braze the coil case G to the plate portion L of the stator B at the corners H to fix the coil case G.
Since it is necessary to caulk and join at the outer periphery of the upper lid C of the upper end K of the coil case G, a large number of manufacturing steps are required, and a large caulking machine is required, resulting in a high manufacturing cost.

Further, when the solenoid coil is broken or burnt, the solenoid coil needs to be replaced, but in this case, the entire electromagnet described above must be replaced, which is uneconomical.

On the other hand, Japanese Unexamined Patent Publication No. 2-114502 discloses that the upper plate C is a substantially cylindrical plug having a screw, and the tip of the guide tube A is welded to the outer peripheral surface of the cylinder of the plug. However, in such welding, it takes time to weld because the welded portion of the weld needs to be reliable, and there is a possibility that local defects, that is, poor weldedness or pinholes may cause insufficient strength or oil leakage. It was Further, in Japanese Utility Model Laid-Open No. 57-80807, instead of the upper plate C, a deeply drawn guide tube is inserted with one end of a cylindrical plug having a constriction in the central part open, and the guide tube at the constricted part is inserted. Is fixed by rolling and caulking. With such a structure,
Since it can be processed in a shorter time than in the case of welding and there are no local defects such as welding defects, there is little risk of insufficient strength or oil leakage.

(Problems to be Solved by the Invention) However, in the case of Japanese Utility Model Laid-Open No. 57-80807, since the plug is surrounded by the entire guide tube, complicated processing such as a screw at the tip of the plug or the guide tube cannot be performed. In addition, positioning is difficult because the plug is inserted into the guide tube for processing. Furthermore, since the caulking of the plug and the guide tube is performed by rolling caulking, there is a problem that a large caulking machine is still required. An object of the present invention is to provide a DC electromagnet which is easy to manufacture even if the tip of the guide tube has a complicated shape, has a small number of steps, does not require a large caulking machine, and has a low manufacturing cost.

(Means for Solving the Problems) Therefore, the present invention has solved the problems of the prior art by providing a DC electromagnet having the configuration described in the claims.

(Example) Next, the Example of this invention is described with reference to drawings. In FIG. 1 showing an embodiment of the present invention, reference numeral 1 denotes a main body of a molding member of an electromagnet, which encloses a guide tube 2 at a central portion thereof and has a solenoid coil 8 having a current-carrying wire 14 wound around a coil bobbin 7 and a magnet. It incorporates the yokes 5 and 6 and the coil case 21 which are the paths. The O-rings 12 and 15 prevent water and the like from entering the mold member body 1. A thin guide tube 2 with a flange made of a cylindrical non-magnetic material that is press-formed through the center of the mold member main body 1 is provided, and one end surface (right side of the drawing) of the guide tube 2 with respect to the center axis of the cylinder is provided. A flange portion 19 is formed at a right angle on the outside of the cylinder, and a flange portion 20 is formed on the inside of the cylinder on the other end surface (left side of the drawing, portion II).

As shown in detail in FIG. 2, the stepped portion 26 of the threaded plug 10 is inserted through the O-ring 13 inside the flange portion 20 formed on the other end surface of the guide tube 2. It Further, since the threaded plug 10 is preformed with the annular protrusion 30 shown by the broken line, it is necessary to caulk the fixing tool 27 and the tip as shown in FIG. 3 after being inserted into the guide tube 2. The caulking jig 28 having an angle θ presses in the direction of the arrow, and as shown by the solid line in FIG. 2, the brim portion 20 of the guide tube 2 is caulked and connected so as to be sandwiched by the annular protrusions 30.

Further, the male screw portion 22 and the hexagon nut 9 of the threaded plug 10 are fixed by clamping the plate 17 via the washer 11 by the collar portion 19 at the right end of the guide tube 2 with the mold member body 1 of the electromagnet sandwiched inside. There is.

As a result, an oil chamber 25 is formed in the guide tube 2, and a cylindrical plunger 3 that reciprocates in the l dimension so as to move back and forth in the axial direction and a rod 23 that is attached to the plunger 3 and reciprocates. A cylindrical stator 4 that holds the fitting state is provided. In this case, the stator 4 is positioned and fixed to the valve body of the hydraulic switching valve (not shown) by the end surface 24 of its enlarged portion.

A small hole 18 is provided in the plunger 3 as an escape port for oil.

As shown in FIG. 1, the rod 23 is slidably inserted into the center hole 4'of the stator 4 by the plunger 3 and is slidably inserted into a driven body (not shown) of the DC electromagnet, such as a spool of a hydraulic switching valve. Abutted. When the electromagnet does not act, the plunger 3 is returned to the other end side by the spring attached to the spool of the hydraulic switching valve.

In the embodiment configured as described above, the electromagnet can be rotated by loosening the hexagon nut 9, so that the current-carrying wiring 14 can be set at an arbitrary position, and the hexagon nut 9, By removing the seat 11 and the seal 12, the solenoid coil 8 can be easily taken out together with the mold member body.

The O-ring 13 of the present invention is provided to prevent the oil in the oil chamber 25 from leaking from the caulking portion, and the caulking portion only needs to have strength. On the other hand, with the above-described welding, it is difficult to weld the O-ring in a small space because the O-ring is melted by the welding heat, and the welded portion has both strength and oil tightness. Need functionality. Further, in the caulking process, since the flange portion 20 of the guide tube is brought into contact with the stepped portion 26 of the plug 10, the positioning is simple and accurate, and the processed state is visible from the outside. Further, even if the tip shape of the plug attached to the tip of the guide tube is complicated, it can be processed.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the plug having the O-ring between the outer circumference of the plug and the guide tube and the guide tube are caulked. There is no problem of insufficient strength or oil leak cylinder due to welding defects. In the caulking process,
Since a step is provided on the circumference of the plug and the flange of the guide tube is brought into contact with this step and crimped by the annular protrusion, complicated tip shape processing is possible and positioning is easy and accurate. Moreover, since the processing state is visible from the outside, processing errors can be prevented. Therefore, it does not require a large caulking machine, it is easy to manufacture and the number of steps is small,
Manufacturing costs can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is an enlarged vertical sectional view of a portion II in the figure, FIG. 3 is a vertical sectional view showing a caulking procedure of the embodiment, and FIG. 4 is a vertical sectional view showing a conventional technique. 2 ... Guide tube, 3 ... Plunger, 4 ... Stator, 7 ... Coil bobbin, 8 ... Solenoid coil, 9 ... Hexagon nut, 10 ... Threaded plug, 11 ...
Washer, 13 ... O-ring, 14 ... Conductive wiring, 17 ... Plate, 19 ... Collar part, 20 ... Collar part, 22 ... Male screw part, 25 ...
… Oil chamber, 26 …… Step section, 27 …… Fixing tool, 28 …… Caulking jig, 30 …… Circular convex section.

Claims (1)

(57) [Claims] 1. A plunger disposed movably in a non-magnetic cylindrical guide tube forming an oil chamber, a stator provided at one end of the guide tube, and a coil bobbin surrounding the guide tube. In an electromagnet, which is provided with a solenoid coil provided with the solenoid coil, and the plunger is moved by energizing the solenoid coil,
One end of the guide tube is attached to the outside and a flange is formed on the inside of the guide tube at the other end, and has a (threaded portion) annular convex portion, a step portion and an O-ring groove from the head end. The oil chamber is formed by inserting an O-ring into the O-ring groove of the plug, abutting a flange portion formed inside the guide tube to the step portion, and caulkingly coupling with an annular convex portion of the plug. A DC electromagnet characterized by the above.