Measuring and testing – Fluid pressure gauge – Diaphragm
Reexamination Certificate
2001-01-08
2002-08-13
Oen, William (Department: 2855)
Measuring and testing
Fluid pressure gauge
Diaphragm
Reexamination Certificate
active
06431004
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pressure sensitive sensor for detecting an external force by a housing elastically deformed by external pressure and electrodes provided in the housing contacting each other, and to a pressure sensitive sensor terminal processing method and manufacturing method.
2. Description of the Related Art
There are pressure sensitive sensors in which a plurality of electrodes made of metal plates, metal wires or the like are disposed within an elastically deformable housing so as to be spaced apart from one another. The housing is elastically deformed by pressure such that the plurality of electrodes contact one other, thereby causing electrical continuity, or a short-circuit, so that the pressure is detected.
In such a pressure sensitive sensor, terminal portions are open in order to be coupled to a connecting means, such as a cord, extending from a determination means such as a computer. Therefore, usually, the connecting means and the electrodes are coupled and then sealed to prevent malfunctioning resulting from, for example, entry of water. From the viewpoints of the reliability of the seal and work efficiency in the sealing operation, it is preferable that the seal used is formed by, for example, molding the terminal portions of the pressure sensitive sensor including the vicinity of the terminals of the connecting means with a synthetic resin material from the outside, in a state in which the terminals of the electrodes are connected to the connecting means.
However, when molding is carried out by using a synthetic resin material, while the connecting means and the electrodes are coupled, the terminal portions of the pressure sensitive sensor are put into the interior of a mold or the like. In this state, molten synthetic resin material is injected to effect molding as in the case of injection molding. Therefore, there is the possibility that the pressure applied during injection of the synthetic resin material will cause the electrodes exposed from the end portion of the housing to contact each other and make electrical continuity.
In addition, there is the possibility that during molding, the molten synthetic resin material will enter the spaces between the electrodes and such that dead zones are formed in places in the pressure sensitive sensor.
Due to these possibilities, it has been difficult to actually carry out terminal processing by molding.
SUMMARY OF THE INVENTION
In consideration of the above facts, a first object of the present invention is to obtain a pressure sensitive sensor and a pressure sensitive sensor terminal processing method capable of ensuring reliability of a seal, improving work efficiency of the sealing operation and enhancing reliability of the sensor itself.
To attain the first object stated above, the pressure sensitive sensor in a first aspect according to the present invention comprises: an insulating housing having a hollow interior and open terminal portions, said housing being elastically deformable by an external force; a plurality of electrode held within said housing in a state in which at least one end of each of said electrodes is pulled out and the respective electrodes are set apart from one another with a space therebetween, said electrodes being deformed by an external force acting on said housing so as to contact one another to make electrical continuity; an insulating spacer provided to come in contact with said plurality of electrodes correspondingly to the inner terminal portions of said housing in which said spacer insulates said plurality of electrodes respectively; and an insulating seal sealing the terminal portions of said housing as well as said electrodes and said spacer.
According to the pressure sensitive sensor having the above structure, the terminal portions of the housing are sealed by the seal portion. Therefore, no foreign matter such as water droplets, enters the housing from the opening portions of the terminal portions, thus preventing erroneous operation. Here, a spacer is disposed between the plurality of electrodes at the terminal portions of the housing. This, even if external pressure (i.e., pressure from the exterior of the housing) acts thereon, the electrodes do not contact one another and thus do not make electrical continuity. For this reason, even if pressure acts on the housing when the terminal portions of the housing are sealed by the seal portion, this pressure does not cause the electrodes to contact each other. This makes it easy to form a seal portion by molding with, for example, a synthetic resin material, thereby making it possible to enhance work efficiency and to reduce costs.
The pressure sensitive sensor preferably comprises a support member supporting connecting portions which connect connecting means and said plurality of electrodes, said connecting means electrically connecting said plurality of electrodes to a determination means from sides of the terminal portions of said housing, said determination means determining whether said plurality of electrodes are contacting one another so as to make electrical continuity said support member together with said plurality of electrodes and said spacer being sealed by said seal.
According to the pressure sensitive sensor having the above structure, the support member which supports the connecting means for electrically connecting the electrodes and the determination means is, together with the electrodes and the spacer, sealed by the seal portion. Accordingly, no foreign matter such as water droplets adheres to the connecting portions of the electrodes and the connecting means at the support member, thus making it possible to prevent erroneous operation. Further, sealing by the seal portion enables improvement of corrosion-resistance and maintenance of the states of the electrical and mechanical connection.
Furthermore, as stated above, if the seal portion is formed by, for example, molding with synthetic resin material, and the synthetic resin material, when molten, is provided with viscosity and stickiness, then the seal portion supports the connecting portions of the support member from the outer side. In this sense as well, it is possible to maintain the state of mechanical connection.
Preferably, the support member is integral with the spacer in the pressure sensitive sensor.
According to the pressure sensitive sensor having the above structure in which the support member is integral with the spacer, the number of parts can be decreased and costs can be reduced. In addition, if the spacer is inserted between the electrodes from the terminal portion of the housing, the support member can be naturally arranged in the vicinity of the terminal portion. In this state, the support member has been positioned, and thus, the work efficiency in the assembly process improves.
A pressure sensitive sensor terminal processing method of a second aspect according to the present invention is a method for sealing terminal portions in a pressure sensitive sensor in which at least one end of each of a plurality of electrodes is pulled out and the plurality of electrodes are fixed, so as to be spaced apart from each other with a space therebetween, in an insulating housing whose interior is hollow and which is elastically deformed by external pressure and at which the terminal portions, which are open, are provided, the pressure sensitive sensor sensing external pressure by the plurality of electrodes being made to contact each other, due to the external pressure, so as to make electrical continuity, wherein disposing an insulating spacer in the space between said plurality of electrodes to come in contact with said plurality of electrodes correspondingly to the inner terminal portions of said housing in which said spacer insulates said plurality of electrodes respectively; and sealing the terminal portions of said housing as well as said spacer by an insulating seal member.
According to this pressure sensitive sensor terminal processing method, the terminal portions of t
Horii Koji
Ishihara Hidenori
Kashiwazaki Shigeru
Nakahigashi Fumitaka
Tsuge Noboru
Asmo Co., Ltd. & Hitachi Cable, Ltd.
Oen William
Parkhurst & Wendel LLP
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