Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Polarity-responsive
Reexamination Certificate
2001-09-05
2002-11-19
Barrera, Ramon M. (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Polarity-responsive
C335S202000
Reexamination Certificate
active
06483407
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an electromagnetic relay wherein one of the flanges of the spool is arranged inside of an opening of a case and a stationary terminal is attached to this spool. In particular, the invention relates to an electromagnetic relay wherein the problem of dust occurring at the time of the attachment of the stationary terminal is solved and the stationary terminal (in particular, a portion where a stationary contact point is provided). can be implemented so as to become attached in an excellent condition.
BACKGROUND TECHNOLOGY
In general, in an electromagnetic relay a movable contact point and a stationary contact point are arranged on the side (hereinafter referred to, in some cases, as the rear side of the case) opposite to the terminal side where the edges for connection of the terminals are lead out. Then, as for the above electromagnetic relay, in many structures the movable contact point shifts in the direction of the coil axis so that the switching with respect to the stationary contact point is carried out to the conductive condition (contact condition). In such an electromagnetic relay of a conventional type, as may be seen in Japanese unexamined patent publication S56(1981)-93234 (first prior art), the stationary terminal, wherein a stationary contact point is secured on one end, is attached by a manner such as compressive insertion to a thick portion provided in a flange, located on the rear side of the case of a spool made of resin around which a coil is wound. Here, as may be seen in FIG. 2 of Japanese examined utility model publication H3(1991)-12198 (second prior art), there is also a type where the other side of the stationary terminal (edge portion for connection) is pushed into a base (substrate) which is arranged outside of the flange on the side of the terminal of the spool in a condition of penetration so as to support and fix the stationary terminal.
Here, in recent years, miniaturization and cost reduction have been increasingly required for a compact type electromagnetic relay (small type where the dimension of height is, for example, 20 mm, or less) which is mounted on a circuit substrate, or the like, in order to be mounted in a car. Therefore, further reduction of the number of portions and assembly structure of each portion in a high density have become important. Therefore, as is disclosed in Japanese unexamined patent publication H10(1998)-162712 (third prior art), a type of relay wherein one of the flanges of the spool is made to function as a base has appeared. That is to say, a member called a base which is conventionally the foundation of the assembly is eliminated and one of the flanges of the spool around which a coil of the electromagnet is wound is arranged inside of the opening of the case in the relay.
In addition, in this type of compact electromagnetic relay, which is the most widely used type,, the relay is usually sealed (that is to say, sealed type relay) in order to withstand cleaning after the mounting of the substrate or in order to secure a predetermined waterproof or dustproof condition. In particular, the cleaning of the above is carried out after soldering for the mounting of the substrate. Therefore, the relay is rapidly cooled down from the heated condition by a cleaning liquid. As a result of this, a difference in atmospheric pressure occurs between the inside and the outside of the relay so that the cleaning liquid is easily absorbed into the inside even through a slight gap and, therefore, an extreme airtightness is required.
DISCLOSURE OF THE INVENTION
(Technical Problem to be Solved by the Invention)
In the above conventional relay there is the problem that defects in performance are easily caused by dust which occurs due to the attachment of the stationary terminal. In addition, in the above conventional relay there is the problem that a stationary terminal (in particular, a portion where a stationary contact point is provided) cannot be implemented so as to achieve the attachment in an excellent condition.
More precisely, in the case of the first stationary terminal is secured to the flange located in the rear side of the case of the spool in the vicinity of the stationary contact point by a manner such as compressive insertion. Therefore, at the time of this securing, the resin material forming the spool is shaved by the stationary terminal, which is of metal, so that an insulating dust (shavings) occurs and this dust easily enters in between the points of contact. As a result of this, the possibility of the occurrence of the obstruction of the points of contact (fluctuation of contact resistance, defective conductance of the contact point, or the like) due to the above dust is high.
In addition, in the first prior art a structure where the flange on the rear side of the case is secured in the vicinity of the stationary contact point of the stationary terminal is provided. Therefore, the position (in particular, the position in the direction of the coil axis) of the stationary contact point changes due to deformation (warping) of the above flange in the direction of the coil axis and the contact pressure changes and, therefore, an excessive dispersion of the operational characteristics easily occurs.
That is to say, a force (i.e. pressure in the direction of the coil axis) works so that the tightly wound coil in the spool of an electromagnetic relay is led to the outside. In particular, the flange of the spool is thin in the compact (small-sized) electromagnetic relay as described previously. Thereby, a considerable amount of deformation (warping) in the form of a curved surface occurs in the flange of the spool due to the above pressure in the direction of the coil axis. As a result of this, the stationary contact point is also displaced due to the above deformation and, therefore, there is the risk that the characteristics differ greatly from the design value.
Here, a shift in the position of the contact point in the lateral direction has a comparatively small effect on the characteristics such as contact resistance and can be covered by the contact size. However, the displacement of the stationary contact point in the direction of contact (that is to say, the direction of the coil axis) along which the movable contact point shifts greatly affects the contact pressure and causes a great fluctuation in the operational characteristics and, therefore, this is, in particular, a problem.
On the other hand, in the case of the second prior reference, the place to which the stationary terminal is secured by pushing, for instance, for fitting is the base arranged outside of the flange on the terminal side of the spool which is a position far away from the stationary contact point or from the movable contact point. Therefore, the possibility of the occurrence of the obstruction of the contact point due to dust, as described above, is comparatively low. In addition, there is no problem of fluctuation in the characteristics due to deformation of the flange. However, the second prior art provides a structure wherein the entirety of a long stationary terminal is supported at only one end portion (side of the end portion for connection). Therefore, it is difficult to maintain the position of the stationary terminal as a whole in a sufficiently fixed manner (to secure the strength) and there is the problem that the positioning precision of the stationary contact point on the side of the other end is poor. Furthermore. when sufficient holding strength is to be assured by increasing supporting distance of the terminal, which has been compressively inserted within the base, then corresponding thickness of the base must become larger. Therefore, there is the disadvantage that the dimensions of the entire relay increases so as to become a larger type or the coil space decreases so that the attraction characteristics of the electromagnet become worse.
In addition, in the electromagnetic relay for mounting on a substrate as described above, of which miniaturization is strongly required, it is ne
Kubota Nobuyoshi
Matsuda Kazuhisa
Matsuo Ken-ichi
Nakata Muneo
Barrera Ramon M.
Morrison & Foerster / LLP
Omron Corporation
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