DE102006053421A1 - vibration generator - Google Patents

Abstract

The invention relates to a vibration generator for a radio with a swinging arm (2) which can be fastened to a carrier (4) and has at least one bend or an angled region and is coupled to a piezoactuator.

Description

A vibration generator with a piezoelectric element is from the document US 5,229,744 known.

A to be solved The task is to specify another vibration generator which is particularly efficient.

It becomes a vibration generator provided for generating a vibration alarm with a swingable Swing arm specified, the at least one bend or an angled Area, wherein the swing arm coupled to a piezoelectric actuator is.

By The specified embodiment of the swing arm manages to be a special size Length of the To achieve swing arm with a small size. The great length has the advantage that thus a low oscillation frequency can be achieved can. A further lowering of the oscillation frequency can be achieved by a be effected connected to the swing arm weight.

Of the Swing arm is on a support fixable. The bend may be formed as a fold.

Of the Swing arm is in a preferred embodiment except for its in or attached to the carrier End range capable of vibration. A first end of the swing arm is preferably oscillatable and a second end on or in the carrier attached.

Of the carrier is preferably the housing or a circuit board of a radio, which is preferably portable.

Of the Piezo actuator can be connected to a voltage source, from which it vibrates is electrically driven.

Of the Piezo actuator has a body on, in which several parallel internal electrodes can be arranged alternately connected to a first and a second outer electrode are. The outer electrodes are preferably on the opposite lying side surfaces of the body arranged. These side surfaces are arranged in a variant parallel to the main surface of the swing arm. You can alternatively stand perpendicular to the main surface of the swing arm.

Of the Swing arm preferably has a major surface which is substantially parallel to the surface of the carrier is arranged. The swing arm has an angled in a variant or curved Coupling area on, which is coupled to the carrier is. The coupling region is in a variant perpendicular or oblique to the main surface of the Swing arm arranged.

Of the Swing arm is in an advantageous embodiment as a U-piece with two Thighs and a yoke connecting the thighs, d. H. Connector, formed. That of the connector opposite end of the first, z. B. upper leg is preferably freely swingable, whereas that of the connector opposite end of the second leg is coupled to the carrier. The second, z. B. lower leg preferably has a major surface, parallel to the main surface the first leg is aligned, and at least one angled at least Area provided for attachment to the carrier or in the carrier interior is.

Of the Swing arm is preferably made of an electrically conductive material manufactured and can be used as an electrical supply line to the piezoelectric actuator to be used. The swing arm is preferably in one piece, for example formed from a multi-curved sheet metal.

Of the Includes swing arm in a further variant, a preferably reinforced with glass fibers plastic. The surface the swing arm can in this case have a metallization, which are used as an electrical supply line to the piezoelectric actuator can.

The running parallel to the carrier surface main areas the legs have in a variant different from each other lengths on. The length the main surface of the to the carrier coupled thigh of the U-piece can be bigger than that of the thigh be chosen with a free end. But it can also be shorter chosen become.

Of the Piezoelectric actuator is in a variant on the first or second leg of the U-piece attached and spaced from the other leg. The piezoelectric actuator can but also be arranged between the thighs of the U-piece, being he from the connector preferably spaced. The piezoelectric actuator is in this case preferably clamped between the legs and biased.

In a variant, a preferably electrically insulating intermediate layer is arranged between the piezoactuator and the oscillating arm. The intermediate layer is preferably provided as an adhesive layer for imparting adhesion between the actuator and the swing arm. The piezoelectric actuator is firmly connected in one variant by means of the intermediate layer over the entire surface with the swing arm. Alternatively, it is possible to ver the piezoelectric actuator with the swing arm via connecting elements bind, which are arranged at a distance from each other and serve as spacers to form a gap between the actuator and the swing arm.

Of the Piezoelectric actuator is in an advantageous variant between the swing arm and the carrier arranged, preferably clamped and biased.

At the free swinging end of the swing arm, preferably at the end of first leg, in a variant, a weight is attached. Of the Weight value is - depending on the length the swing arm and the weight of the piezoelectric actuator - preferably chosen such that in the vibration generator, a predetermined resonance frequency is achieved. The piezoelectric actuator is preferably excited with an electrical signal, its frequency at the resonant frequency of the vibration generator or near this frequency is.

For transmission the vibration of the actuator body to the swing arm transmission elements are in an advantageous variant provided between the actuator and the respective leg of the U-shaped folded swing arm are arranged. Each transmission element preferably has a rejuvenation on. As a transfer element In particular, a prism is suitable whose base surface with the actuator body preferably firmly connected. The edge facing away from the base surface and an area of the prism adjacent to this edge touches the Swingarm. There is a possibility alternatively the actuator body with such rejuvenations train to form a contact surface between to minimize the actuator and the swing arm.

Of the Swing arm preferably has at least one shape, in a contact region of the piezoelectric actuator or the transmission element projects into it. The shape is formed in a variant in the form of a groove and for example by a bulge or notch of the swing arm educated. If the piezo actuator is biased between the swing arm and the carrier can be in the vehicle also be provided such a shape.

The Alignment of the vibration axis of the piezo actuator, d. H. an axis, along which the vibrations of the actuator body are excited corresponds preferably the maximum cross-sectional size, d. H. the length, the Body. Thus, you can Vibrations are excited with the lowest frequency. Other Alignments of the vibration axis are also possible.

The Vibration axis of the piezoelectric actuator is at a fixed to the swing arm Piezoactuator preferably in the longitudinal direction aligned this swing arm. At the deformation of the actuator a firmly connected to this area of the swing arm is pulled along and thus deformed. Due to the expansion of the actuator when applying an electrical voltage occurs a mechanical bending stress on, which deflects the swing arm. With corresponding cyclical excitation of the actor Thus, vibrations of the system are stimulated that the composite of the actuator and the swing arm comprises.

The Vibration axis of the piezoelectric actuator, between two main surfaces of the Leg of the swing arm is arranged, is preferably perpendicular to these main surfaces, that is, perpendicular to the orientation of the legs of the swing arm, aligned.

Of the Piezo actuator can have two bodies comprise mutually oppositely directed polarization axes. These bodies are in a first variant z. B. by gluing to form a Composite of the body firmly connected. This composite is with the swing arm firmly connected, creating a composite of the body and the swing arm comes.

In In a second variant, the swing arm is arranged between these bodies. Every body is firmly connected to the swing arm, creating a composite of the body and the swing arm comes about. In both cases, at the suggestion of the Piezoaktors bending vibrations of the composite of the body and the swing arm caused.

Of the specified vibration generator will now be based on schematic and not to scale Figures explained. Show it:

1 in cross-section a vibration generator with a swing arm in U-shape with unequal length of legs, wherein the lower leg a piezoelectric actuator is attached;

2 in cross-section a vibration generator with a swing arm in U-shape with unequal length of legs, wherein a piezoelectric actuator is attached to the upper leg;

3A in cross section an exemplary piezoelectric actuator;

3B in a perspective view of another exemplary piezoelectric actuator;

4 a variant of in 1 shown vibration generator, in which between the piezoelectric actuator and the swing arm a gap. is formed;

5 in cross section a vibration generator with a piezoelectric actuator which is clamped between a swing arm and a carrier;

6 in cross-section a vibration generator with a swing arm in a U-shape, wherein between the legs of the swing arm, a piezoelectric actuator is arranged;

7 in cross-section a vibration generator with a swing arm having the formations for receiving the piezoelectric actuator;

8th in a perspective view of a piezoelectric actuator with tapered edge regions.

In the 1 is a vibration generator with a swing arm 2 shown, which is angled several times, with one end, namely attachment area 2d , the swing arm in the vehicle 4 is attached.

The swing arm 2 has a U-piece with a lower leg 2a and an upper leg 2 B and a yoke, ie connector 2c on, that's the thighs 2a . 2 B combines. The main surfaces of the thighs 2a . 2 B are at rest parallel to the surface of the carrier 4 aligned.

At the top of the lower thigh 2a is a piezoelectric actuator 1 attached. At the free end of the upper thigh 2 B is a weight 3 attached. The lower thigh 2a is shorter than the upper leg 2 B , In this case, a particularly large oscillation amplitude of the free end of the swing arm can be achieved.

In the variant according to the 1 is the piezoelectric actuator 1 though between the thighs 2a . 2 B arranged, but only on the lower leg 2a coupled while he is from the upper thigh 2 B is spaced. In the 2 is indicated that the piezoelectric actuator on the upper leg 2 B can be arranged.

Between the piezo actuator 1 and the leg to which it is coupled is according to the 2 an intermediate layer 5 arranged. This layer is preferably electrically insulating if an electrical contact between the actuator and the electrically conductive swing arm 2 should be prevented. However, this layer may also be electrically conductive, if an electrical contact, for example, between the lower outer electrode of the actuator and the electrically conductive swing arm 2 is intended.

The piezo actuator 1 comprises in an advantageous variant, a body having a plurality of piezoelectric layers, which preferably contain ceramic. Between the piezo layers are internal electrodes 7 and on the surface of the body external electrodes 71 . 72 arranged, see 3A . 3B , Several first internal electrodes are conductive with the first external electrode 71 and a plurality of second internal electrodes with the second external electrode 72 connected. First and second internal electrodes are arranged alternately. The outer electrodes 71 . 72 are over connecting wires 9 electrically contactable.

The surfaces of the internal electrodes 7 in the variant according to the 3A are parallel to the bearing surface of the piezoelectric actuator 1 , ie parallel to the surface area of the swing arm 2 arranged to which the piezoelectric actuator 1 is coupled. In this case, vibrations are excited parallel to the internal electrodes with the piezoelectric coefficient d ₃₁ . The lower area of the outer electrode 71 can in this case by means of a conductive adhesive, ie a conductive intermediate layer 5 , conductive with the swing arm 2 be connected. The overhead area of the outer electrode 72 is with a connecting wire 9 connected. Alternatively, it is possible, the arranged on the side surfaces of the actuator body portions of the outer electrodes 71 . 72 contact via connecting wires.

The surfaces of the internal electrodes 7 in the variant according to the 3B are perpendicular to the contact surface of the piezoelectric actuator 1 arranged. In this case, vibrations are excited perpendicular to the internal electrodes with the piezoelectric coefficient d ₃₃ . So that a short circuit between the outer electrodes 71 . 72 can be prevented, the piezoelectric actuator in this case, preferably by means of an electrically insulating intermediate layer 5 on the swing arm 2 attached.

In the 4 a variant is shown in which between the piezoelectric actuator 1 and the lower leg of the swing arm 2 , to which the actuator is attached, an air gap is provided. The actuator is connected to the swing arm by means of connecting elements 6 connected, which serve as spacers to form the gap.

In the 5 is implied that the length of the lower leg can go to zero, so the swing arm 2 is formed in principle as an L-piece, whose angled portion 2c in the carrier 4 is attached.

The piezo actuator 1 is in this case between the main surface 2 B the swing arm and the carrier arranged. The location of a contact area between the actuator and the surface 2 B determines the length of a swingable area of the surface 2 B formed lever arm and its oscillation frequency.

The actuator is from the angled area 2c the swing arm 2 spaced, but arranged near this area. Alternatively, the actuator can directly adjoin this area.

In the variant according to the 6 is the piezoelectric actuator 1 between the thighs 2a . 2 B of the U-shaped swing arm 2 arranged. The carrier 4 forms in this case a housing in which the vibration generator is included. In other embodiments, the carrier 4 be formed as a housing.

In the 7 is indicated that the lower leg of the swing arm 2 in principle longer than the upper one can be selected.

In the variant according to the 7 is between the piezo actuator 1 and the respective leg of the swing arm 2 a transmission element 8th arranged, which is preferably fixedly connected to the actuator body or part of this body. The transmission elements 8th serve to transmit vibrations from the piezoelectric actuator 1 on the swing arm 2 , Every transmission element 8th is formed in the form of a prism, whose base surface faces the piezoelectric actuator, see 8th ,

For receiving a contact region of the transmission element 8th is in each leg a groove-shaped formation 10 educated. The shape 10 is formed as a bulge.

The internal electrodes 7 are in the arrangement of the actuator between the legs of the swing arm 2 preferably as in the variant according to 8th aligned parallel to the major surfaces of the legs. The vibration in this case becomes perpendicular to the internal electrodes 7 excited with a piezoelectric coefficient d ₃₃ .

A different orientation of the internal electrodes is also possible in principle, wherein in particular a piezoelectric effect can be exploited, which is characterized by piezoelectric coefficients d ₃₁ and d ₁₅ .

The Embodiment of the vibration generator, in particular the shape of the Swing arm and the internal structure of the piezoelectric actuator, is on the in The examples shown in the figures are not limited.

1

piezo actuator

2

swing arm

2a

lower Thighs of the U-piece

2 B

upper Thighs of the U-piece

2c

joint

2d

fastening area

3

Weight

4

carrier

5

interlayer

6

fasteners

7

internal electrodes

71,

72 external electrodes

8th

transmission element with rejuvenation

9

leads

10

formation

Claims (11)

Vibration generator for a vibration alarm, - with one on a support ( 4 ) attachable, oscillatable swing arm ( 2 ) having at least one bend, - wherein the swing arm ( 2 ) is coupled to a piezoelectric actuator. Vibration generator according to claim 1, - wherein the oscillating arm ( 2 ) has an angled end portion which is attached to the support ( 4 ) is coupled. Vibration generator according to claim 1, - wherein the oscillating arm ( 2 ) is formed as a U-piece with two legs and a connecting piece connecting the legs, - wherein the end facing away from the connecting piece of one of these legs to the carrier ( 4 ) is coupled. Vibration generator according to claim 3, - wherein the to the carrier ( 4 ) Coupled leg shorter than the leg is formed with a free end. Vibration generator according to claim 3, - wherein the to the carrier ( 4 ) coupled leg longer than the leg is formed with a free end. Vibration generator according to one of claims 3 to 5, - in which the piezoelectric actuator attached to one leg of the U-piece and the other Leg is spaced. Vibration generator according to one of claims 3 to 6 - in which the piezoelectric actuator is biased between the legs of the U-piece. Vibration generator according to one of claims 3 to 6, - wherein the piezoelectric actuator between the swing arm ( 2 ) and the carrier ( 4 ) is biased. Vibration generator according to one of claims 1 to 8, - wherein at the freely oscillating end of the swing arms ( 2 ) a weight ( 3 ) is attached. Vibration generator according to one of claims 1 to 9, - wherein the oscillating arm ( 2 ) has at least one shape in which a contact region of the piezoelectric actuator projects into. Vibration generator according to claim 10, - in which the piezoelectric actuator has a taper in cross-section, in the Forming protrudes into it.