JPH0376207A - Manufacture of plunger guide for solenoid - Google Patents

Abstract

PURPOSE:To enhance processing accuracy, and to improve durability, hysteresis characteristics, attraction force characteristics and the like by a method wherein magnetic metal material and non-magnetic metal material are formed by conducting a two-layer cold drawing work in such a manner that the non-magnetic metal material is formed in the desired thickness and outside diameter, and a plurality of magnetic metal material rings are integrally formed in axial direction on the outer circumference of the magnetic metal material. CONSTITUTION:A two-layer cold drawing work is conducted on a magnetic round steel bar, on which non-magnetic metal material such as copper and brass is wound around, and the layer 2 of the non-magnetic metal material outside the center part 1 of copper is formed in the desired diameter D and thickness (t). An intermediate article 4, having the layer 2 of non-magnetic material, is formed on the steel main body 3 and its circumference by cutting the above-mentioned material into the desired length (l). A plunger is formed by conducting a cutting work on the intermediate article 4 and by eliminating unnecessary part completely leaving several parts which are necessary as rings 5 of width W among the layer 2. As heat is not added to the magnetic material as in the case of a padding work, the adverse effect of heat can be removed, the plunger can be formed in fixed shape, and hysteresis and attraction characteristics can also be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a method for manufacturing a plunger for a solenoid, and more particularly to a plunger having a thin ring made of a non-magnetic material on its outer periphery.

(b) Conventional electromagnetic valves, especially plungers for proportional solenoid valves, have a thin non-magnetic metal (e.g. copper or copper-zinc alloy) on the outer periphery of the plunger as a method to improve hysteresis characteristics and increase attraction characteristics. ) rings are joined in a headwind shape.

The conventional method of joining this ring to the outer periphery of the plunger is by metal spraying or brazing welding to the outer periphery of the plunger P to a desired width W (the axial length of the plunger), as shown in Fig. 3(C). A common method is to build up the material, then cut and polish the outer periphery by machining.

However, with such conventional methods, there are problems in that the heat for overlaying has an adverse effect on the metal part (adhesion of oxide scale or dimensional change), and post-processing or machining such as removing scale and cutting the outer periphery. There are problems in that the shape of the built-up layer cannot be made constant, and that hysteresis and suction force characteristics are poor. Furthermore, the number of processing steps (pre-processing, overlay processing,
There is also the problem that there is a lot of post-processing (such as grinding, etc.), which increases the cost.

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are to provide a method for manufacturing a plunger for a solenoid, by using two-layer cold drawing process, and to perform overlay processing and subsequent post-processing. The purpose is to omit the above-mentioned problems of the conventional method.

(d) Means for Solving the Problems The method for manufacturing a plunger for a solenoid according to the present invention involves surrounding the outer periphery of a magnetic metal material with a non-magnetic metal material, and forming two cold layers of the magnetic metal material and the non-magnetic metal material. The non-magnetic metal material is formed by drawing to have a desired thickness and a desired outer diameter, and the non-magnetic metal material is cut into an annular shape excluding a plurality of locations separated in the axial direction, thereby forming the magnetic material. The bottom of the tank is formed such that a plurality of rings of non-magnetic metal material are integrally formed on the outer periphery of the metal material while being spaced apart in the axial direction.

(e) Effect In the above configuration, since heat is not applied to the magnetic material constituting the body of the plunger as in build-up processing, the adverse effects caused by it can be eliminated, and the shape of the ring can be made constant, reducing hysteresis and attraction force. Characteristics can be kept constant.

(f) Example Embodiments of the present invention will be described below with reference to the drawings.

In the manufacturing method of the present invention, first, a non-magnetic metal material such as copper or brass is wound around the outer periphery of a round bar made of magnetic material used for a normal plunger, and then a material is processed by a known two-layer cold drawing process. The outer diameter of the layer 2 of non-magnetic metal material outside the copper core 1 is the desired diameter as shown in FIG.

Shape the bottom so that it has a thickness of t. The product thus drawn is cut into a desired length l as shown in FIG. 1(B). This produces an intermediate product 4 having a steel body 3 and a layer 2 of non-magnetic metal material around its outer periphery.

Next, cutting is performed on this intermediate product 4, leaving only a few parts (two in this example) of the layer 2 that are necessary for the ring 5 having a width (the axial length of the plunger) W, and removing unnecessary parts. It is completely removed to form a plunger 6 as shown in FIG. 1(C).

As shown in FIG. 2, since it is necessary to fit and fix the bushing rod 7 to the end face of the plunger 6, the processing for forming the hole is carried out in the same manner as in the conventional method. In the same figure, 8 is a plunger guide; 9 is a fixed iron core.

(g) Effects According to the plunge manufacturing method of the present invention, the following effects can be achieved.

■ Machining accuracy is greatly improved by double-layer cold drawing of the plunger, and plungers with excellent durability, hysteresis characteristics, suction force characteristics, etc. can be manufactured.

■ Eliminates the negative effects of heat unlike the brazing method.

■ Conventional manufacturing methods such as the brazing method had to rely on loft production (manual work), but the method of the present invention enables mass production through automation.

■ Machining time can be significantly shortened and machining costs can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 [0 to C] is a diagram explaining the method of manufacturing the plunger of the present invention, Fig. 2 is a sectional view showing an example of use during plunging, and Fig. 3 is an example of the conventional method of manufacturing the plunger. It is a diagram. 3; Body 5; Ring 6; Plunging

Claims (1)

[Claims] The outer periphery of the magnetic metal material is surrounded by a non-magnetic metal material, and the magnetic metal material and the non-magnetic metal material are subjected to two-layer cold drawing processing so that the non-magnetic metal material has a desired thickness and a desired outer diameter. and cutting the non-magnetic metal material into an annular shape except for a plurality of axially spaced locations, thereby integrally forming a plurality of rings of the non-magnetic metal material on the outer periphery of the magnetic metal material spaced apart in the axial direction. A method for manufacturing a plunger for a solenoid, characterized in that a plunger is formed.