JPS583243Y2 - magnetic switch - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a magnetic switch having a structure in which a plastic material is used for a contact holding shaft that holds a movable contact.

This invention will be explained below based on an embodiment shown in the drawings.

In FIGS. 1 to 3, 1 is a switch body, 2 is an excitation coil housed in the switch body, and 3 is one end fixed to a movable iron core (not shown), and the other end has a groove 3a for a movable contact. A contact holding shaft to hold, 4 a movable contact mounted on the holding shaft 3, 5 a movable contact for holding the contact pressure of the movable contact.
(1) a spring mounted on the holding shaft 3; (11) a fixed contact provided opposite the movable contact 4 and fixed to the case 7; and (8) a groove 3a of the contact holding shaft 3; A retaining ring 9 is a return spring stretched between the retaining ring 8 and the case.

In the device configured as described above, when the excitation coil 2 is excited, the contact holding shaft 3 moves in conjunction with the movable iron core (not shown) mentioned above and moves to the left in the figure, so that the movable contact 4 is moved to the fixed contact 6.
, 6' to close the circuit as is well known.

By the way, the magnetic switch having the above structure is characterized in that the movable contact holding shaft 3 is made of plastic material and no insulating material is used to insulate the movable contact 4 as in the past. 3, as shown in Fig. 2, the groove 3a into which the retaining ring 8 fits has a small diameter, and when manufacturing and molding this, air is filled in the groove 3a, or glass fiber is added to strengthen the material. If a mixture of During each operation, the retaining ring 8 moves axially within the groove 3a.
There was a problem that this portion 3a broke due to the movement in the direction.

This state is shown in Figs. 2 and 3, with Fig. 2 showing the movement of the retaining ring 8 before operation, and Fig. 3 showing the movement of the retaining ring 8 during operation and load fluctuations in the groove 3a of the movable contact holding shaft 3. .

In order to eliminate these drawbacks, this invention prevents breakage of the movable contact holding shaft 3 by regulating the force of the contact return spring and the force of the contact contact pressure spring, making it more compact and durable. The purpose of this invention is to provide a magnetic switch with high performance.

That is, the reason why the load changes in the groove 3a portion of the movable contact holding shaft 3 is due to the existence of a gap g between the retaining ring 8 and the groove 3a, and the fact that the force of the contact return spring 9 is weaker than that of the contact pressure spring 4. However, since it is difficult to eliminate the above-mentioned gap g, if the retaining ring 8 is always pressed against the movable contact 4 side, load fluctuations will not occur in the groove 3a of the movable contact holding shaft 3 every time it is operated. Groove 3 of movable contact holding shaft 3
Part a will not break.

As described above, according to this invention, the force of the return spring for returning the contact is set to be stronger than the force of the spring that maintains the contact pressure in the closed state of the contact, thereby increasing the force of the movable contact holding shaft made of plastic. This has the effect of preventing breakage defects and making it possible to downsize.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the magnetic switch, FIG. 2 is a sectional view showing the state of the gap in the groove on the movable contact holding shaft before operation, and FIG. 3 is a sectional view during operation. In the figure, 1 is the switch body, 2 is the excitation coil, 3 is the contact holding shaft, 4 is the movable contact, 5 is the spring, 6.6'
is a fixed contact, 7 is a case, 8 is a retaining ring, and 9 is a return spring. In the figures, the same reference numerals indicate the same parts.

Claims (1)

[Scope of utility model registration request] A return for returning the movable contact from a closed state to an open state in a device comprising a fixed contact, a movable contact that can close the fixed contact, and a contact holding shaft that holds the movable contact and is made of a plastic material. A magnetic switch characterized in that the force of the spring is set to be greater than the force of the spring that maintains contact pressure when the contact is in a closed circuit state.