RELATED APPLICATIONS

This Application is a national stage filing under 35 U.S.C. 371 of International Patent Application Serial No. PCT/CN2018/084478, filed Apr. 25, 2018, entitled “ULTRA-SMALL ELECTROMAGNETIC RELAY WITH HIGH STATIC CONTACT POINT POSITIONING PRECISION”. Foreign priority benefits are claimed under 35 U.S.C. § 119(a)-(d) or 35 U.S.C. § 365(b) of Chinese application number 201710311555.1, filed May 5, 2017.

TECHNICAL FIELD

The present disclosure relates to the technical field of relay, in particular to an ultra-small electromagnetic relay with high stationary contact positioning precision.

BACKGROUND

In the related art, the stationary spring, the base and the bobbin of a relay are generally formed by integral combined injection molding, thereby achieving an effect of reducing volume and improving insulation capacity. Stationary contacts have been welded on the stationary spring before the stationary spring, the base and the bobbin are injection molded. Therefore, how to ensure positioning precision of the stationary spring during injection molding, and then ensure positioning precision of the stationary contact has a great influence on consistency of the product.

An ultra-small electromagnetic relay in the related art is shown inFIG. 1toFIG. 5.FIG. 1is a structural schematic diagram of stationary spring strips in the related art.FIG. 2is a schematic diagram of a stationary spring and a bobbin matching with each other in the related art.FIG. 3is a schematic diagram of a stationary spring and a bobbin matching with each other (in a reverse state relative to the structure ofFIG. 2) in the related art.FIG. 4is a structural schematic diagram of a stationary spring, a bobbin and a base which are integrated by injection molding in the related art.FIG. 5is a structural schematic diagram of a stationary spring, a bobbin and a base which are integrated by injection molding (in a reverse state relative to the structure ofFIG. 4) in the related art, wherein a stationary contact102has been welded on a contact surface101of a stationary spring100. After the stationary spring100is matched with the bobbin103, the stationary spring100, the bobbin103and the base104are formed an integrated structure by injection molding. In the ultra-small electromagnetic relay, when a contact part of the stationary spring100and the bobbin103are formed a base structure by the injection molding, the positioning location of the stationary spring100in a mold is generally at an edge of the stationary spring close to an outside of the base. In the related art, two locations positioning method is adopted to achieve positioning the contact102of the stationary spring100. wherein a first positioning is at a leading-out terminal of the stationary spring along a width direction of the base, which is equivalent to providing a first positioning part105at the leading-out terminal of the stationary spring100. A second positioning is at a local leading-out terminal along a length direction of the base, which is equivalent to providing a second positioning part106at an end of one side of the contact surface101of the stationary spring100. Since a direct positioning of a center position of the contact of the stationary spring100is not achieved, the positioning method has following drawbacks.

1. The positioning is not complete and stable. The direct positioning is not performed at a contact position of the stationary spring. If the stationary spring at the contact position is slightly deformed and tilted and is not corrected by the positioning, it will result in poor positional consistency of the contact after the injection molding is performed to form the base, thereby affecting the consistency of parameters such as a contact gap and overtravel of the relay, and not conducive to improve product productivity and performance consistency.

2. The positioning at the contact position is unstable, which is easy to result in that the contact position of the stationary spring will be impacted by the flow of liquid plastic injected from the mold gate when the base is injection molded, and then the stationary spring is easy to be deformed in a direction of opening and closing of the mold, and a gap is generated between the stationary spring and the mold, all of which results in occurrence of injection burrs at the position and affects performance quality of the product. The method in the related art for dealing with these defects is generally to reduce direct impact of the liquid plastic at the contact position of the stationary spring by changing structures of the gate and location of components of the base, or by changing the parameters of process of the injection molding. These changes will greatly increase the difficulty of design of the base and the mold and production control.

3. Since the position of the surface of the stationary spring is close to the mold cavity (the terminal protruding at the position of the stationary spring contact, that is, a part where the second positioning part106is covered with plastic in the length direction of the base), it is easy to cause the stationary spring to interfere with the mold and then damage the mold, and affect the cost and efficiency of manufacturing.

SUMMARY

The technical solution adopted by the present disclosure to solve the technical problem thereof is as follows. An ultra-small electromagnetic relay with high stationary contact positioning precision including a stationary spring, a bobbin and a base which are integrated by injection molding, and the stationary spring includes a stationary spring body on which stationary contacts are disposed and a leading-out terminal of the stationary spring extending from the stationary spring body to an outer part of the base; in the leading-out terminal of the stationary spring, a first positioning part configured to position the stationary spring during injection molding is disposed at a position corresponding to an edge in a width direction W of the base; wherein in the stationary spring body, a convex extending part is provided in a length direction L corresponding to the base, and the convex extending part extends outside the base and is designed as a second positioning part during the injection molding; in the base, a through hole formed through the base in the thickness direction T of the base is provided at a position corresponding to a back surface of the stationary spring body on which the stationary contact is mounted, the back surface of the stationary spring body on which the stationary contact is mounted is designed as a third positioning part during injection molding, so that the positioning part can be supported and positioned by a positioning member inserting through of the through hole of the base.

The convex extending part extending outside the base and designed as a second positioning part during injection molding may be cut off to stretch out or not stretch out the outside of the base in the length direction L of the base after the injection molding is completed.

The bobbin is located between the stationary spring body of the stationary spring and the base, and the bobbin is configured to give way to the through hole of the base, so that a positioning member passing through the through hole of the base can bypass the bobbin at a back surface of the stationary contact to support and position the third positioning part of the stationary spring body.

One end which is close to the inner position of the base of the through hole is abutted against the back surface of the stationary spring body being opposite to the stationary contact or the back surface of the stationary spring body close to the stationary contact.

A cross-section of the through hole is designed as a circular shape or a square shape or a triangular shape or a polygon shape or an ellipse shape.

The diameter of the through hole is gradually decreased in the direction from the outer position to the inner position of the base.

The edge of the stationary spring body of the stationary spring is provided with at least one hook which is integrally extended outwardly and bent by the static spring body, and the hook is embedded in the base.

A bending angle of the hook is approximately 90 degrees.

The size of the hook is gradually increased from the root part toward the free end of the hook.

The embodiments of the present disclosure are further described in detail below with reference to accompanying drawings. However, the structure of the present disclosure is not limited to illustrated embodiments.

