JPS59865Y2 - Ultrasonic transducer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic transducer for a depth sounder, a fish finder, etc., and is applied to cases where the ultrasonic transducer is used in a field with strong shaking.

Generally, under conditions of severe vibration, in the configuration of a conventional transducer that is fixedly held, the radiation surface from the housing becomes the oscillator radiation surface, so the orientation direction of the radiation surface is constantly fluctuates with the oscillation, making ultrasonic transmission and reception with the main target extremely inaccurate.

The present invention eliminates the drawbacks of the conventional type due to this vibration, which causes inaccuracies in transmitting and receiving ultrasonic waves, with a simple configuration.
This also takes into account the response to temperature changes.

The details will be explained below. In the figure, a cymbal ring 3 is rotatably held at a fulcrum 2 inside a sealed housing 1.

This gimbal ring 3 rotatably holds the vibrator holding plate 5 at a fulcrum 4.

A vibrator 6 is fixed to the lower part of the vibrator holding plate 5, and a floating ball 7 is fixed to the upper surface thereof.

The mounting center of gravity of the vibrator 6 is set lower than the fulcrums 2 and 4, and the mounting buoyancy position of the floating ball 7 is set higher than the fulcrums 2 and 4.

The vibrator 6 includes an element 6a that performs ultrasonic vibration, a winding 6b, and a radiation plate 5c that holds the radiation surface 6a' of the element 6a with adhesive.

In order to make the vibration of the element 6a effective in the radial direction, it is constituted by a reflective material 6d that covers the entire surface of the element 6a except for the radiation surface 6a'.

The reflective material 6d is generally made of a soft elastic material (for example, neoprene rubber sponge) that evenly contains a large number of closed cells.

Further, the winding 6b of the internal vibrator 6 is connected to the outside by a lead wire 8 via a metal fitting 9.

A radiation plate 10 made of a material that does not impede the transmission of ultrasonic waves (for example, neoprene rubber, etc.) is fixed to the flange 1' portion of the bottom surface of the sealed housing 1 in a sufficiently watertight manner.

Furthermore, a partition wall 11 is provided on the inside upper part of the sealed casing 1 in such a range that the float 7 inside the interior does not come into contact with it even if it swings.

This partition wall 11 is provided with a plurality of communication holes 11' penetrating from its upper surface to its lower surface, and an appropriate amount of liquid 13 and gas 14 are introduced into the sealed case 1 through the liquid inlet 12 provided on the upper wall of the sealed case 1. Fill below the allocation.

The liquid 13 is a liquid substance that easily transmits ultrasonic waves (for example, water,
The gas 14 is a substance having a lower compressibility than the liquid 13 (for example, air, nitrogen gas, etc.).

When filling the liquid 13, an appropriate amount is injected while allowing air bubbles to escape to the upper surface of the partition wall 11 through the through hole 11' so that no gas 14 remains on the lower surface of the partition wall 11.

In addition, when using this device, the flange 1 at the bottom of the sealed housing 1
A holding body 15 (e.g., the bottom of a ship), which is moving at
Fixed side up.

The operation and effect of the above configuration will be explained.

When this transducer is fixed to a swinging holder 15, the sealed housing 1 swings together with the holder 15.

At this time, in the sealed housing 1, the vibrator holding plate 5 moves to align its axis with the earth normal direction by the restoring torque of the synergistic gravitational force and buoyancy of the fixedly held vibrator 6 and floating ball 7.

This movement is performed at the fulcrum 2. Cymbal ring 3. As long as the closed housing 1 and the vibrator holding plate 5 are rotatably supported via the fulcrum 4, it goes without saying that this restoring operation can be expected in all horizontal directions.

Further, the liquid 13 provides buoyancy to the floating ball 7, and also has the effect of quickly attenuating the swing amplitude of the vibrator holding plate 5 by utilizing the liquid viscosity.

In addition, when the gas 14 existing on the upper surface of the partition wall 11 mixes with the liquid 13 due to rocking and generates bubbles or sometimes an emulsion, the partition wall 11 reduces the buoyancy of the floating ball 7 or This has the role of preventing disturbances to the movement and interference with the ultrasonic transmission and reception of the transducer 6 due to ultrasonic noise induced when bubbles are generated and disappear.

Next, temperature is the second most severe condition in the environment in which a transducer is used, second only to vibration.

In particular, in the case where the holder 15 is a part of the bottom of a ship in a transducer used in the ocean, the nautical range is wide, and the difference in temperature of the seawater in contact with the transducer varies significantly depending on farsightedness.

Corresponding to this temperature difference, the liquid 13 within the sealed casing 1 expands and contracts in volume depending on the ambient temperature at the time.

When the sealed casing 1 is filled with the liquid 13, the compressibility of the liquid is extremely small (for example, in the case of water, the compressibility is 2
4.75 x 10-'' cm2/kg at 0° C.) Therefore, the liquid pressure inside the sealed casing 1 changes significantly due to the expansion and contraction of the liquid 13, sometimes leading to the rupture of the sealed casing 1 from within.

Moreover, this pressure change compresses or expands the reflective material 6d constituting the vibrator 6, shrinks or expands the bubble group held inside the reflective material 6d, and sometimes destroys the bubble group. reach.

This fluctuation or destruction of the bubble group within the reflective material 6d severely reduces the ultrasonic transmission/reception ability of the element 6a, sometimes making it irrecoverable.

The present invention, which has this serious flaw, has a structure in which liquid 13 and gas 1 are placed inside the sealed housing 1 in order to alleviate changes in liquid pressure within the sealed housing 1.
4 in an appropriate ratio (as described above, the partition walls 11
Inject the amount of liquid so that the level of liquid 13 is above the
By using the fact that the compressibility of the gas 14 is significantly higher than that of the liquid 13, the expansion and contraction of the liquid 13 due to changes in external temperature is absorbed by the compression and expansion of the gas 14, and the pressure inside the sealed casing 1 is significantly increased. It is possible to moderate the increase and decrease, to minimize changes in the bubble group of the reflective material 6d, and to prevent the ultrasonic transmission and reception function of the vibrator 6 from deteriorating.

As mentioned above, the present invention has a simple configuration that can sufficiently adapt to the harsh conditions of vibration and temperature that have been problems in the past in ultrasonic transducers. It is industrially very effective.

[Brief explanation of the drawing]

Figure 1 is a top view of the transducer of the present invention, and Figure 2 is the top view of the transducer of the present invention.
A cross-sectional view taken along the A-A' axis in the figure, Figure 3 is B in Figure 1.
It is a sectional view taken along the -B' axis. 1... Sealed housing, 1'... Flange, 2
...Fulcrum, 3...Gimbal ring,
4... Fulcrum, 5... Vibrator holding plate, 6
...Resonator, 6a...Element, 6a'.
...Radiation surface, 6b... Winding, 6C...
...Radiation holding plate, 6d...Reflector, 7...
...Floating ball, 8...Leader wire, 9...Watertight penetrating hardware, 10...Radiation plate, 11...
・Partition wall, 12...Liquid inlet, 13...
Liquid, 14... Gas, 15... Holder, 16... Medium.

Claims (1)

[Scope of utility model registration request] It has an ultrasonic radiating plate on the bottom, has an ultrasonic transducer and a floating ball fixed on the bottom and top, respectively, and is rotatably held via a gimbal, as well as a sealed casing filled with liquid and gas. An ultrasonic wave transmitter/receiver having a structure in which a gap on the inside thereof is divided into two by providing a partition wall having a plurality of communication holes that communicate with each other.