Ultrasonic transducer

The invention is based on an ultrasonic transducer with a pot-like housing with an annular wall and with a bottom surface as a diaphragm, a piezo-element which is connected with connection lines being arranged at the inner side of the bottom surface.

An ultrasonic transducer having a pot-shaped housing is known from EP 0 075 302 B1. Ultrasonic transducers of this type are used, for example, as sensors for distance measuring devices.

It is the object of the present invention to suggest an ultrasonic transducer with stable contacting suitable to mounting.

This object is met in the ultrasonic transducer according to the invention in that the edge remote of the bottom surface is surrounded by a decoupling ring and in that the decoupling ring is formed as a holder for the connection lines.

In a first advantageous embodiment form of the ultrasonic transducer according to the invention, the decoupling ring substantially fills the housing and is provided with bore holes for holding the connection lines.

In a second embodiment form, the decoupling ring has a central opening and grooves are arranged at the edge of the latter for holding the connection lines. In this case, it is advantageous when a portion of the interior of the housing not occupied by the decoupling ring, including the central opening, is filled with a damping material.

An advantageous construction of the ultrasonic transducer according to the invention consists in that the connection lines are constructed so as to be flexible. Nevertheless, due to the holding of the flexible connection lines, which are formed by cords, for example, it is possible to mount the ultrasonic transducer according to the invention on a printed circuit board in a simple manner, and the connection lines fit through the holder into the bore holes which are arranged in the respective grid dimensions provided.

In another advantageous construction of the ultrasonic transducer according to the invention, the connection lines held in the decoupling ring are constructed so as to be rigid and are connected with the piezo-element via flexible sections of line. Simple mounting is likewise ensured in this case. In this construction, it is preferably provided that the decoupling ring, besides the bore holes for holding the connection lines, also has an opening and that the opening and a portion of the interior of the housing not occupied by the decoupling ring are filled with a damping material. In this construction, the rigid connection lines can be guided out in a straight manner or can be bent outside the housing by 90°.

In order to accurately maintain the position of the connection lines and their spacing in spite of the elastic characteristics of the decoupling ring, it can be provided according to a further development that the connection lines are held at the surface of the decoupling ring by a crosspiece or web which is preferably ring-shaped.

Embodiment examples of the invention are shown in the drawing in several Figures and described more fully in the following description.

FIG. 1 shows a first embodiment example in four views;

FIG. 2 shows a second embodiment example in four views; and

FIG. 3 shows a third embodiment example in three views.

Identical parts are provided with identical reference numbers in the Figures. The Figures show the embodiment examples considered from the radiating direction or reception direction (a), in a top view from the connection side (b) and in longitudinal section (c) and (d).

Each of the embodiment examples shown in the drawings contains a sensor transducer pot 1 which is made of aluminum, the piezo-element 2 being fastened, for example, glued in, on the inner side of the bottom of the sensor transducer pot 1 . A decoupling ring 4 , 6 , 9 is provided for the purpose of mounting the ultrasonic transducer in a stationary part, for example, in a part of a motor vehicle body, this decoupling ring 4 , 6 , 9 being made of elastic material, preferably silicone, and embracing the edge of the transducer pot 1 . A corresponding contour of the transducer pot 1 and on the outer side of the decoupling ring 4 , 6 , 9 serves for secure fastening simply by pressing into a corresponding opening of the body part, not shown.

In the embodiment example according to FIG. 1, connection cords 3 contact the piezo-element 2 . The decoupling ring 4 comprises a central opening whose edge is provided with grooves for holding the connection cords 3 . The remaining hollow spaces are filled up with a damping material 5 , for example, foamed silicone.

In the embodiment example according to FIG. 2, the decoupling ring 6 is formed in such a way that it occupies the entire interior space of the sensor pot 1 . A bore hole running through the entire decoupling ring 6 is provided for the connection cords 3 .

In the embodiment example according to FIG. 3, two rigid connection lines 4 are provided, each being connected with the piezo-element 2 via a flexible line 7 . The rigid connection lines 8 are in turn held in the decoupling ring 9 ; an additional web 10 made of a material with low elasticity additionally fixes the connection lines 8 in position. Also, in the embodiment example according to FIG. 3, the hollow spaces are filled with a damping material 11 .