JP2006319592A - Ultrasonic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that an acoustic matching layer 2 is corroded away by chemicals in the case of a conventional ultrasonic sensor. <P>SOLUTION: An acoustic matching layer 8 is mounted on the bottom of a case 7, a piezoelectric ceramic 9 is mounted on the acoustic matching layer 8, a screw part 11d formed at a lower end of a lid part 11 is fitted into a screw part 7a formed near an upper end of the case 7, flat packing 12 is mounted on the lid part 11 with which the top edge of the case 7 is brought into contact, O-ring packing 13 is attached on a side part of the lid part 11 with which a part near the top edge of the case 7 is brought into contact, a cable 10 is pulled out through a hollow part 11b of a pulling-out part 11a formed at the upper part of the lid part 11, a connector 14 is mounted on the top end of the pulling-out part 11b of the lid part 11 to thereby prevent liquid from intruding from the top end of the pulling-out part 11a, and a mounting screw 11c for mounting an ultrasonic sensor is formed at a side face of the upper end of the pulling-out part of the lid part 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic sensor that can be used in a chemical environment, in which a piezoelectric ceramic and an acoustic matching layer are sealed by a case and a lid so that ultrasonic vibration is not transmitted to the outside.

  Conventionally, as shown in FIG. 2, the piezoelectric element 1 is fixed to the acoustic matching layer 2, and the cylindrical case 3 is fixed to the acoustic matching layer 2 so as to surround the piezoelectric element 1, and is cylindrical so as to fill the piezoelectric element 1. An ultrasonic sensor in which a case 3 is filled with an elastic resin 4 and a connector 6 is connected to the piezoelectric element 1 via a cord 5 has been proposed.

In the conventional ultrasonic sensor configured as described above, since the acoustic matching layer 2 is exposed, there is a problem that when this ultrasonic sensor is used in a chemical environment, the acoustic matching layer 2 is corroded by the chemical. .
Japanese Patent Laid-Open No. 10-224895

    The problem to be solved is that in the conventional ultrasonic sensor, the acoustic matching layer 2 is corroded by chemicals.

  In the present invention, the acoustic matching layer is attached to the bottom of the case, the piezoelectric ceramic is attached to the acoustic matching layer, the cable is configured to pull out a cord to which the piezoelectric ceramic is connected, and the lid portion is a side portion of the case. The screw part that fits into the screw part formed in is formed in the fitting part, and the cable is drawn out through the connector attached to the drawer part formed in the upper part, and the flat packing is connected to the case of the lid part. It is attached to the contact surface.

  In the ultrasonic sensor of the present invention, by using an O-ring packing or a flat packing between the case and the lid, confidentiality is provided between the case and the lid, and vibrations generated from the piezoelectric ceramics are generated. There is an advantage that it is not transmitted to the member attached to the drawer portion via the lid portion.

  In the present invention, in order to use the ultrasonic sensor in a chemical environment, an acoustic matching layer is attached to the bottom of the case, piezoelectric ceramics are attached to the acoustic matching layer, a lid is screwed to the case, A flat packing and an O-ring packing were used between the lids.

  FIG. 1 is a side sectional view of an ultrasonic sensor according to an embodiment of the present invention. An acoustic matching layer 8 is attached to the bottom of a case 7, and a piezoelectric ceramic 9 is attached on the acoustic matching layer 8. The cords 10 a and 10 b drawn from the cable 10 are connected to the upper and lower surfaces, and the screw portion 11 d formed at the lower end of the lid portion 11 is fitted to the screw portion 7 a formed near the upper end of the case 7, thereby The flat packing 12 is attached to the lid portion 11 in contact with the upper portion of the case 7, and the O-ring packing 13 is attached to the side portion of the lid portion 11 in contact with the vicinity of the upper end of the case 7. The cable 10 is pulled out through the hollow portion 11b in the inside, and the connector 14 is attached to the upper end of the drawer portion 11a of the lid portion 11 to prevent liquid from entering from the upper end of the drawer portion 11a. It constitutes the, also mounting screw 11c for mounting the ultrasonic sensor to the upper end side of the lead portion 11a of the lid portion 11 is formed, further by molding resin into the case 7.

  In the ultrasonic sensor of this embodiment configured as described above, the case 7 and the lid portion 11 are integrally formed by screw fitting, the acoustic matching layer 8 and the piezoelectric ceramic 9 are mounted in the case 7, and screw fitting is performed. Since the flat packing 12 or O-ring packing 13 is attached to the mating portion to prevent the invasion of chemicals, the acoustic matching layer 8 and the piezoelectric ceramic 9 are contaminated with chemicals even when used in a chemical environment. In addition, by sealing the resin in the case 7, it is possible to further provide hermeticity. Also, the case 7 and the lid portion 11 are screw-fitted and a flat packing is provided in the vicinity of the screw-fitting. By mounting the 12 or O-ring packing 13, the vibration generated from the piezoelectric ceramic 9 is blocked by the flat packing 12 or the O-ring packing 13, and transmitted to the outside via the mounting screw 11 c of the lid 11. There is the advantage that it will not be.

  In the above embodiment, the resin molded in the case 7 is preferably a fluororesin, and the packing attached to the fitting portion between the case 7 and the lid 11 is either the flat packing 12 or the O-ring packing 13. Good.

It is side surface sectional drawing of the ultrasonic sensor of the Example of this invention. It is side surface sectional drawing of the conventional ultrasonic sensor.

Explanation of symbols

7 Case 8 Acoustic matching layer 9 Piezoelectric ceramics 10 Cable 11 Lid 12 Flat packing 13 O-ring packing 14 Connector

Claims (4)

  An acoustic matching layer attached to the bottom of the case, a piezoelectric ceramic attached to the acoustic matching layer, a cable for drawing a cord connected to the piezoelectric ceramic, and a screw portion formed on the side of the case A screw part to be fitted to the lid is formed in the fitting part, and is attached to the contact surface between the lid and the case so that the cable is pulled out via a connector attached to the drawer part formed on the upper part. An ultrasonic sensor characterized by comprising a flat packing.   The ultrasonic sensor according to claim 1, wherein an O-ring packing is attached to an upper portion of the screw portion of the lid portion.   The ultrasonic sensor according to claim 1, wherein a mounting screw is formed on a side portion of the drawer portion of the lid portion.   The ultrasonic sensor according to claim 1, wherein a resin is filled around the acoustic matching layer and the piezoelectric ceramic in the case.

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