JPH041700Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a mounting structure for a push rod for an oil-immersed solenoid.

(b) Prior Art Conventionally, there have been the following structures for attaching a push rod to the plunger of an oil-immersed solenoid, each of which has its own problems.

(1) As one structure, as shown in Fig. 4, the push rod r may be press-fitted into the hole h in the axial center of the plunger p, or it may be brazed.
Or it is attached using an adhesive.

However, in the case of press-fitting, an axial force is applied to the push rod r, so if the force increases beyond a certain level, the push rod r will bend. There was a problem with exiting from h.

In addition, in the case of brazing, push rod
There was also a problem that the plunger p was heated. Furthermore, in the case of adhesive bonding, there was a problem in that a gap was required between the hole h and the push rod r, and excess or overflowing adhesive had to be removed.

Also, in any of these three methods, when inserting the push rod r into the hole h,
A hole v is required to allow the air inside to escape.

(2) Other structures, as shown in Figure 5,
There is a device in which an annular groove g is formed on the outer periphery of the push rod r, and the inlet corner c of the hole h of the plunger p is caulked so as to project into this groove to fix the push rod r.

However, if the caulking thickness varies around the annular groove g when caulking the corner c, there is a problem that the push rod r tends to be inclined with respect to the plunger p, making the caulking process difficult. .

(3) As another structure, as shown in Fig. 6, a groove s is formed between both ends of the hole h of the plunger p, and the end face e of the push rod r is pressed in the axial direction. There is a device in which a push rod r is fixed to a plunger p by expanding the outer periphery of the plunger to form a convex portion t, which is fitted into a groove s.

However, it is difficult to form a convex part t on the push rod r and to fit it into the groove s (this is due to the small outer diameter of the push rod of 4 to 6 mm), and it is also difficult to process it due to the pressure force in the axial direction. There was a problem that the push rod could bend.

(c) Problems to be solved by the invention The problem to be solved by the invention is that in the structure in which the push rod of the solenoid is attached to the plunger, it is possible to process the solenoid without bending or heating the push rod during processing. To easily fix a push rod to a plunger without requiring skill, and to ensure that a push rod is fixed to a plunger with correct dimensions.

(d) Means for solving the problems The present invention provides a solenoid push rod mounting structure in which an axial hole is formed in the center of the plunger and a push rod is inserted into the axial hole.
forming an uneven portion on the outer periphery of the end of the push rod;
A hole extending inside the uneven portion is formed in the end portion, and a steel ball is press-fitted into the hole, so that the uneven portion bites into the inner wall of the axial hole of the plunger, and the push rod is inserted into the axial hole. The structure is characterized in that it is fixed to.

(E) Effect In the solenoid push rod mounting structure having the above configuration, when the push rod and plunger are attached, the uneven portion of the push rod is expanded in the radial direction by the steel ball, so a large axial force is not applied to the push rod. This is not necessary, and the combination of the two can be ensured.

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

In FIG. 1, reference numeral 100 denotes an oil-immersed solenoid equipped with a solenoid push rod mounting structure (hereinafter referred to as mounting structure) 1 according to the present invention,
The end of the push rod 2 is a hole formed in the center of the plunger 3 in the axial direction (hereinafter referred to as the axial hole).
It is inserted in 31.

The plunger 3 is movably inserted into a guide sleeve 6 fixed to the inside of the pressure tube 4 via a guide presser 5. A fixed iron core 7 is fixed to one end of the pressure tube 4, and a stopper 8 is fixed to the other end.A coil 9, a frame 10, and a bonnet 11 are arranged around the outer periphery of the pressure tube 4. A push button 12 is inserted into a hole formed in the center.

As shown in FIGS. 2 and 3, the mounting structure 1 includes one or more annular grooves 21 formed on the outer periphery of the end of the push rod 2 to form a concave and convex portion. A hole 22 is formed in the center in the axial direction. The hole 22 is formed so as to form a large diameter part 22a with a large diameter at the entrance of the hole on the end face, and a small diameter part 22b with a slightly smaller diameter at the deeper part. The depth of the hole 22 is determined by considering the position of the groove 21 so that when a steel ball 23 whose outer diameter is approximately equal to the inner diameter of the large diameter portion 22a is press-fitted into the hole 22, the protrusions 21a and 21b on both sides of the groove 21 are connected to the plunger. The depth is set to be optimal for biting into the inner wall of the axial hole 31.

In the mounting structure 1 having the above configuration, in order to attach the push rod 2 to the plunger 3, the push rod 2 is inserted into a predetermined position in the axial hole 31 of the plunger 3, and the push rod 2 is attached using a jig (not shown). The relative position of the plunger 3 is fixed so that it does not move. Next, the steel ball 23 is inserted into the hole 22 of the push rod, and the steel ball is pressed into the hole 22 by being pressed by a pressing rod (not shown). Then, as the steel ball 23 advances from the large diameter part 22a to the small diameter part 22b of the hole, the outer periphery of the end of the push rod 2 swells, forming a protrusion 21 defined by the groove 21 of the uneven part.
a, 21b bite into the inner wall of the axial hole 31 of the plunger, and the push rod 2 presses into the axial hole 31.
fixed inside.

(g) Effects The solenoid push rod mounting structure according to the present invention allows the push rod to be fixed at any position in the axial hole of the plunger, so a single push rod can be used to combine several push rods and plungers with several axial dimensions. This fixing method also requires pressing the steel ball in the axial direction of the push rod with a smaller force than the conventional technology, so the push rod does not bend, and the work is simple and easy, just press-fitting the steel ball, and requires skill and precision. No expensive jigs are required.

Further, since the protrusion defined by the outer circumferential groove of the push rod bites into the inner wall of the axial hole of the plunger, it is securely fixed and the push rod will not come off due to impact or the like. Furthermore, since the portion to which the steel ball is press-fitted is located inside the plunger and not on the end face, magnetostriction does not occur due to magnetic properties and will not adversely affect the attractive force.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an oil-immersed solenoid with a push rod mounting structure according to the present invention, Figs. 2 and 3 are partial sectional views of the same, and Figs.
The figure is a sectional view showing a push rod mounting structure according to the prior art. 1... Push rod mounting structure, 2... Push rod, 21... Groove, 22... Hole, 22a...
Large diameter part of the hole, 22b... Small diameter part of the hole, 23... Steel ball, 3... Plunger, 31... Axial hole, 4...
...Pressure tube, 7... Fixed iron core, 8... Stopper, 100... Oil-immersed solenoid.

Claims (1)

[Scope of utility model registration request] In a solenoid push rod mounting structure in which an axial hole is formed in the center of the plunger and a push rod is inserted into the axial hole, an uneven part is formed on the outer periphery of the end of the push rod, and the uneven part is inside the end. A hole extending inside the plunger is formed, and a steel ball is press-fitted into the hole so that the uneven portion bites into the inner wall of the axial hole of the plunger and the push rod is fixed to the axial hole. Push rod mounting structure for solenoid.