JPS6125158Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electromagnetic switch, particularly an electromagnetic switch for an engine starting motor, and relates to an improvement in means for preventing a plunger from falling off from a case.

A conventional device of this type is shown in FIG. In the figure, reference numeral 1 denotes a cylindrical case, and one end thereof has a side wall projecting in the inner diameter direction. 1a
2 is a screw hole provided on the side wall of the case 1, into which a torsion for attaching the case to a starter motor (not shown) is screwed; 3 is an electromagnetic coil attached to the inner periphery of the case 1; 4 is a cylindrical winding frame around which this electromagnetic coil is wound; 5 is a cylindrical bush on the inner periphery of this winding frame; 2
A cylinder made of a non-magnetic material is fixed so as to have the same inner diameter as the cylinder. Reference numeral 6 is a fixed iron core inserted into the left side of this cylinder, and constitutes the magnetic path of the electromagnetic coil 3. 7
A contact rod is slidably inserted into the inner periphery of the fixed iron core 6, and a movable contact (not shown) is fixed to the left end thereof to be connected to a fixed contact (not shown). A plunger 8 is slidably mounted inside the bush 2 and the cylinder 5, and is attracted to the left when the electromagnetic coil 3 is energized. Reference numeral 9 denotes a movable body mounted on the inner circumference of the plunger, and 10 a compression spring mounted between the movable body and the fixed iron core 6, which constantly presses the plunger 8 to the right. Reference numeral 11 denotes an annular body fixed to the right side surface of the case 1, which contacts the right end of the plunger 8 at one location on its circumference to prevent the plunger 8 from falling out of the case 1. A locking piece 11a is formed.

In the conventional device configured as described above, when the plunger 8 is inserted into the cylinder 5 and the bush 2 during assembly, the plunger 8 is pressed to the right by the spring 10 and falls out of the case 1. try to. If this plunger 8 falls off, when an electromagnetic switch is assembled to the starter motor, not only the electromagnetic switch will not function, but the starter motor will no longer function at all. Therefore, conventionally,
After fixing the annular body 11 to the right end surface of the case 1 and inserting the plunger 8 into the cylinder 5 and the bush 2, bend the locking piece 11a of the annular body 11 inward as shown in FIG. The bent portion was brought into abutting engagement with the right end surface of the plunger 8 to hold the plunger 8 in position within the case 1. However, in the conventional case, the annular body 11 must be formed only as a means to prevent the plunger 8 from falling off, and the annular body 11 must be fixed to the case 1.
As a result, the number of component parts and the number of manufacturing steps increase, resulting in extremely low productivity and high costs.

This invention provides an excellent electromagnetic switch that overcomes the above drawbacks.

An embodiment of this invention shown in FIG. 2 will be described below. In FIG. 2, 12 is the winding frame 4.
This is a cylindrical bush that is fitted into the inner circumferential surface of the case 1 and the inner circumferential surface of the side wall protruding in the inner radial direction at one end of the case 1 to allow the plunger 8 to slide smoothly. A locking piece 12a that protrudes in the axial direction is formed at one location on the circumference.
This locking piece 12a extends linearly until the plunger 8 is inserted into the bush 12, and comes into contact with the right end surface of the plunger 8 when the plunger 8 is inserted into the bush 12. The plunger 8 is bent so that it can be engaged and held in position within the case 1.

That is, if configured as described above, the plunger 8
can be prevented from falling off from the case 1 by the locking piece 12a formed on the bush 12, so there is no need to use a member dedicated to preventing falling off like the conventional annular body 11, which reduces material costs. Of course, the number of manufacturing steps can also be reduced. Further, if the bush 12 is made to serve as the conventional cylinder 5 and bush 2, the number of parts can be further reduced.

As described above, this invention has a bush that is fitted and fixed to the inner circumferential surface of one end protruding in the radial direction of the case of the electromagnetic switch to allow the plunger to slide smoothly, and which abuts and engages with the outer circumferential surface of the plunger. Since the locking piece that prevents the plunger from falling out of the case is integrally formed, there is no need to provide any special member to prevent the plunger from falling off, which reduces the number of parts. Since the number of manufacturing steps can be reduced, an electromagnetic switch with good productivity can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional device, and FIG. 2 is a sectional view showing an embodiment of this invention. In the figure, 1 is a case, 2 is a bush, 3 is an electromagnetic coil, 4 is a winding frame, 5 is a cylinder, 6 is a fixed core, 8 is a plunger, 9 is a movable body, 11 is an annular body, 12 is a bush, and 12a is a It is a locking piece. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A cylindrical case in which a cylindrical winding frame around which an electromagnetic coil is wound is housed in its inner periphery and one end protrudes in the radially inner direction; a plunger movably provided along the inner periphery of one end of the frame; a fixed core provided opposite the plunger on the inner periphery of the other end of the winding frame, and attracting the plunger when the electromagnetic coil is energized; , a spring provided between the fixed iron core and the plunger to press the plunger in the anti-suction direction, and a spring fixed to the inner circumferential surface of one end of the case projecting in the inner diameter direction to smoothly move the plunger. A cylindrical bush,
and an electromagnetic switch that is integrally formed with the bushing and includes a locking piece that comes into contact with the outer peripheral surface of the plunger to prevent the plunger from falling out of the case.