IE902986A1 - Piezoceramic transformer - Google Patents

Abstract

In the piezoceramic transformer, the piezoceramic is encapsulated with the electrodes in a housing consisting of silicone rubber encapsulating compound having a Shore hardness of

Description

HOECHST CERAMTEC AG HOE 89/C 008 D.Ph.HS/AP Description Piezoceramic transformer The invention relates to a piezoceramic transformer for 5 transforming electrical alternating voltages.

Piezoceramic transformers are known. By using the reciprocal piezoelectric effect upon application of a primary alternating voltage, they generate a mechanical resonant vibration and convert the latter by the direct piezoelectric effect into a secondary alternating voltage. Since in the generation of high secondary voltages the resonance sharpness, i.e. the mechanical vibrational Q, is also utilized, it is important for mechanical dampings to be avoided or at least kept small. This is also important in order to achieve a useful efficiency.

Since the mechanical damping is essentially dependent upon the type of mount of the piezoceramic, particular care has to be exercised in this regard. The invention is intended to solve this problem by providing a piezotrans20 former with a mount.

It is a typical feature of the piezoceramic transformer according to the invention that the piezoceramic is encapsulated with the electrodes in a housing made of silicone rubber casting compound with a Shore hardness < 40 and the housing is provided with devices for fastening the piezotransformer.

The housing can be arranged in a lost sheathing made of metal, plastic or the like, and the sheathing can have lugs with openings for accepting fastening elements. It is also possible for threaded bolts or nuts to be injected or cast into the housing or the lost sheathing as a device for fastening the transformer. The terminals for the electrodes also come - embodied as soldering spikes into consideration as a fastening device. The transformer - 2 can be inserted and fastened into contact wafers by means of them.

Instead of the spikes, the electrical terminals can also consist of encapsulated nuts and/or threaded bolts.

Furthermore, the housing can contain the capacitive feedback electrode possibly necessary for operation, the capacitors and diodes of a multiplier chain for generating high direct voltage, as well as an electronic control circuit.

Illustrative embodiments of the invention are represented in the drawings and described in more detail below.

Figure 1 shows a piezotransformer encapsulated in a housing and having pigtail leads and a lost sheathing, Figure 2 shows a variant of the piezotrans former in accordance with Figure 1, and Figure 3 shows a piezotransformer encapsulated in a housing and having threaded bolts as electrical terminals and fastening elements.

In the piezoceramic trans former the piezoceramic (1) with the associated electrodes (2, 3, 4) and the electrical terminals (5, 6, 7) are surrounded on all sides by a housing (8) made of low-damping casting compound, e.g. silicone rubber, with a Shore hardness < 40. The housing (8) can be arranged in a lost sheathing (9) made of metal, plastic or the like. For the purpose of fastening the piezotransformer, e.g. to a support, a wafer or the like (not represented), the lost sheathing (9) can be provided with lugs (11) and openings (10), which serve to accept fastening elements. As an alternative to this, the piezotransformer can also be fastened by soldering spikes (12, 13, 14), which serve simultaneously as terminals for the electrodes and are encapsulated in the housing (8) - 3 and, if required, are led in an insulated fashion through the lost sheathing (9) (Figure 2).

In the embodiment according to Figure 3, threaded bolts (15, 16, 17, 18) are encapsulated in the housing (8) as electrical terminals and fastening for the piezotransformer; the same holds for a feedback electrode (19).

The advantage achieved with the invention consists particularly in that the user can install the piezotransformer, as he is accustomed to doing with the usual electronic components, without having to pay particular heed to the mechanical requirements of the piezotransformer. Moreover, considerable savings arise in the manufacturing outlay, if further components, such as a rectifier circuit or control electronics, are also encapsulated.

Claims (3)

1. Patent Claims A piezoceramic transformer, wherein the piezoceramic (1) is encapsulated with the electrodes (2, 3, 4) in a housing (8) made of silicone rubber casting compound with a Shore hardness < 40 and the housing (8) is provided with devices (12 to 18) for fastening the piezotransformer .

The piezoceramic transformer as claimed in claim 1, wherein the housing (8) is arranged in a lost sheathing 3.

3. The piezotransformer as claimed in claim 2, wherein the sheathing (9) has lugs (11) with openings (10) for accepting fastening elements. A piezoceramic transformer according to claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.