WO2009023885A1

WO2009023885A1 - Suppression of vibrations in folding roofs of motor vehicles

Info

Publication number: WO2009023885A1
Application number: PCT/AT2008/000290
Authority: WO
Inventors: Andreas Dantele; Thomas Rittenschober; Markus Gusenbauer
Original assignee: Profactor Produktionsforschungs Gmbh
Priority date: 2007-08-17
Filing date: 2008-08-14
Publication date: 2009-02-26
Also published as: EP2176082A1; AT505708A1; AT505708B1

Abstract

Device for preventing solid-borne sonic vibrations which are caused by the air flowing around the folding roof of a convertible car and which are emitted into the passenger compartment of the vehicle, wherein at least one vibration-sensing sensor (3) composed of a vibration-sensitive functional material which is pliable and flexible like the folding roof and which outputs corresponding sensor data is arranged on the surface regions (20) of the folding roof which have a tendency to vibrate, which vibration-sensing sensor (3) is connected in terms of sensor data flow via a control unit (5) for converting the absolute value range and phase range of the currently occurring vibrations into actuator activation data, and wherein the control unit is connected in terms of actuator data flow to at least one counter-vibration actuator (4) which can be made to vibrate by means of actuator activation data, and the control unit supplies this actuator (4) with phase-shifted actuator activation data which excites the counter-vibrations which cancel out the vibrations of the folding roof.

Description

Vibration suppression in folding roofs of automobiles

The present invention is a new device for

Reduction, in particular to prevent or neutralize, equipped at higher speeds of having a textile or foil folding roof

Motor vehicles, in particular cabriolets, by the air surrounding the folding roof and their turbulence, and possibly there by drive units of the vehicle, caused and radiated into the vehicle interior, auditory frequency exhibiting, disturbing structure-borne vibrations or vibrations, especially in the low-frequency acoustic range, for a significant increase in the acoustic comfort in the

Vehicle interior, according to the O b e r b e g r i f f of the A n s p r e c h e s!

For drivers and passengers uncomfortable are the on convertible with folding top up

Textile or film base occurring from a certain speed, caused by the air flowing past the roof vibrations or vibrations in parts of the driver, the passenger and the passenger compartment spanning closed folding roof or folding top.

Therefore, in recent years, the automobile industry has been steadily advancing the development of sheet-metal folding roofs and the replacement of the conventional textile roofs by them. Reasons for this are in particular the following: Better suitability of the vehicle for colder weather conditions.

Less problems with aeroacoustic phenomena, such as pass-by noise, turbulence noise, and the like.

The folding roofs of four-seater convertibles generally have a larger area and therefore tend to be more likely to excite vibrations due to turbulence and other disturbances caused by the air flowing past when driving.

However, the main disadvantages of sheet metal folding roofs remain the following:

The necessary additional hydraulic actuators with complex mechanics increase the vehicle weight and thus the fuel consumption. There is much more space for accommodating the actuators and

Mechanics compared with textile roofs needed.

The aesthetic appearance due to the chunky rear area is questionable. Many vehicle categories do not allow the integration of sheet metal folding roofs from the outset for the reasons just mentioned. Investigations and measurements on a concrete cabriolet, namely on a sporty two-seater, have shown that disturbing vibrations on a fabric roof, which are initiated by air flow turbulence, in the Audible frequency range, low-frequency vibration components, eg at below 1000 Hz include. It was further found that the frequency content practically does not change with increasing travel speed. The flutter of the rear window and in particular the two-sided lateral membrane areas of the folding roof, are judged to be particularly disadvantageous for the driving and listening comfort.

One of the possibilities which have been investigated to stabilize textile folding roofs of vehicles against alteration thereof as a result of environmental conditions, different driving speeds, age-related changes or the like is described in DE 19518070. The folding top of a cabriolet described therein has an active adjustment system with at least one tensioning cable and an adjusting mechanism, which, e.g. together, depending on the speed of travel, be effective and include a passive adjustment system with at least one adjusting mechanism upstream spring element, whereby changes in the canopy reference voltage can be compensated. From WO 2006/062608 A2 an adjustable structural element for vehicles with a fixed roof has become known, wherein at least a portion of the roof is formed of an active material which is responsive to an activation signal, e.g. in case of a collision, e.g. with another vehicle, and activated in this way, the mechanical and / or structural conditions or properties, eg. change the stiffness of the top or in particular can increase.

The activation signals may preferably be thermal, magnetic or electrical. The active material may be a shape memory material, a magnetic shape memory, a piezoelectric material or the like. Furthermore, devices and methods for the suppression of disturbing periodic

Pressure changes, so ultimately known from acoustically audible vibrations in the interior of vehicles with a fixed roof, which occur when a window and in particular when the sunroof of the car is open.

There, the active element, such as a piezo element, by means of which a targeted vibration-reducing change in the flow direction of the outer flow is achieved by the car. For this purpose, for example, DE 19750218 A1 called.

Furthermore, such device is described for example in US 5812684 A, which are arranged on the sliding side windows of motor vehicles in order to reduce the vibration noise disturbing the occupants. In this case, the disturbing vibrations detecting sensors mounted on the side windows and in addition to the same actuators, which generates targeted in a contrary to the noise generated by the sensor noise-causing vibration phase "backlash", so that the vibrations of the side windows are either canceled or at least substantially reduced. According to this document, the actuators supplying the opposite oscillation are piezoceramic actuators which are arranged both inside and outside on the disc in the disc section which is always remaining in the vehicle door and thus not visible from the outside.

They are controlled by at least one sensor and at least one actuator arranged in close proximity, which produces an output signal proportional to the vibration signal, with a phase opposite to the current vibration, and an amplifier for generating the attenuation signal associated with the Actuator is connected.

Finally, Lecce L. et al: Vibration active control inside a car by using piezo actuators and sensors. Proceedings of Conference on Mechatronics - Efficient Computer Support for Engineering, Manufacturing, Testing and Reliability; 18-22 Sept. 1995. Stuttgart, Germany, pp. 423-432, section 4.5, which prior publication discloses an arrangement of piezoelectric vibration detecting sensors and corresponding counter vibration generating actuators for reducing the vibration induced noise in a vehicle in the roof area thereof describes.

The present invention has set itself the goal of folding roofs or Faltverdecken of cabriolets made of soft, flexible (flat) material, such as in particular of textile or foil-like material, the perceived as unpleasant vibrations in the audible frequency range, from a certain driving speed through the Flow around the vehicle and in particular the folding roof by the outside air arise neutralize, as equal as possible in those areas of the folding top, where they actually occur, in particular the flexibility, flexibility of the folding roofing material is to be considered as an essential aspect.

According to the invention, the use of functional materials at quite specific discrete positions of the folding roof structure is proposed in order to introduce controlled countervailing vibrations into these structures in order thus to prevent disturbances by e.g. To suppress turbulence and possibly also by operating aggregates. Here, the soft flexible nature of the foldable, textile or foil-like roofing material should be fully considered.

The invention thus relates to a device of the type mentioned in the introduction, which comprises the measuring cell which originates from the c e n e c e c e s of the entry n e r c h e s e 1.

The placement of the sensors and actuators formed with the functional or functional materials is based on the already mentioned investigation of the mechanical properties of the textile roof of a real convertible and on the effects of induced by disturbances of the flow around the folding top vibrations to the acoustic comfort in the vehicle interior.

Since it is a forced oscillation of textile fabric roof in the operating condition of the vehicle, it is advantageous to accommodate the functional materials in such a way or in the structure that throughout the operating range of the vehicle by appropriate control, there is the possibility by the flow To simulate generated vibration form, ie to generate an image of the same and then ultimately extinguish the forced oscillation by means of a corresponding counter-image at least substantially.

The corresponding control signals for the functional materials in use as actuators are provided by a control unit, which in turn receives its information about the current state of vibration of the structure to be controlled by sensors, which in turn formed from or with functional materials are and advantageously meet the same requirements with regard to integrability in a vehicle folding roof and flexibility.

The closed system, consisting of sensors or actuators of vibration-passive and / or actively functional materials, an electronic unit or a transducer and amplifier for the sensors that provide the signal conditioning or amplification and a - advantageously integrated into the same - Electronic unit for the training or release of the actuators ultimately activating control signal of the control and regulation unit, in which by means of appropriate algorithms an image of the incoming vibration signals, thus changed by means of anti-vibration signals, the natural vibration behavior of textile roof construction and affects the acoustic comfort in the vehicle interior Suppression of the structure-borne sound emitted by the folding roof positively.

Here, a completely new feature of the invention is that for the first time the mechanical properties of the vibration detection sensors and the counter-vibration actuators are tuned to the genuinen characteristics of the flexible Faltdachmaterials. Thus, further eliminates the previously unavailable installation of ultimately rigid and at least small areas of the folding roof-claiming functional elements. There are vibration detection sensors and close to the same spatially, accordingly energizable counter-vibration actuators provided in the vibratory active areas of the folding roof. If the vibration detection sensor, as advantageously provided according to the invention, is formed from a functional material, a mechanical deformation thereof causes a change in the electrical voltage level at the electrodes attached to this sensor. So causes, for example, in piezoelectric materials, an electric field a

Shape change and vice versa causes a change in shape, a voltage change at the electrodes. Of significant advantage is that one and the same piezoelectric material can optionally be used both as an actuator or drive means and as a sensor. Is the substantially soft-flexible sensor with a flat side flat to the

Tethered membrane bounded, causes a change in shape, in particular a curvature or distortion of the membrane, which then just transferred directly to the vibration detection sensors, a voltage change to the electrodes arranged on this sensor. This design has the further advantage that it can be determined by a corresponding structural shape of the sensor and the effective direction of the deformation and the same can be counteracted.

In a corresponding or correspondingly structured arrangement of the sensors, it is possible to reliably detect deformations and vibration forms occurring there across the membrane or at their flat locations or on the flat side of the folding roof.

If the drive means or the actuator is likewise formed from a piezoelectric material, no moving parts are required for the drive or for the application of the countervibrations. This is of particular advantage since moving or moving drive parts are always subject to wear and are therefore disadvantageous in devices which are designed for the longest possible service life.

According to an advantageous development, the piezoelectric material of the sensors has the piezoelectric effect d31 or d32 or d33. An important advantage of the piezoelectric effect d31 is that a contraction as well as an expansion thereof can be achieved by an electric field applied to such a piezo element.

It is any material suitable for the formation of the drive means or actuator, in which an acting field, be it the same now electrically, magnetically, thermally od. Like., Or an applied electromagnetic radiation, such as light, causes a deformation of an actuator.

It has been found in the context of the invention to be particularly favorable, as the A nspruch 2 refer to, as described so far, functional material to use, which has the properties of the flexibility and flexibility of Faltdachmaterials adapted flexibility, as is the case for example in piezoelectric cable fibers or embedded in elastomers or elastomeric piezoceramics, which, for example, textile or filament-like functional material equal to the context of the textile manufacturing process the folding roof can be integrated.

This is particularly favorable if the functional material is applied in regions of the folding top in which folding of the textile takes place, in particular if it is designed as flat foil bonded to the folding roofing material.

In this sense, it is particularly advantageous if a co-interweaving of the functional material as well as the data and power lines, in the manner of a co-interweaving, is provided, as the A n s p r u c h 3 shows.

The A n s p r u c h 4 relates to the processing of the vibration data supplied by the sensors to the supplied to the actuators counter-vibration data.

Advantageous real details of the new flexible sensors and actuators can be found in the appendix 5.

The A n s p r u c h 6 shows the various possibilities of the basic principles underlying the vibration detection sensors and the anti-vibration generation actuators.

It can be inferred from the invention that sensors and actuators based in particular on the piezo principle, in particular as a result of their technical maturity, are of particular value for the invention.

If the functional elements or sensors and actuators are formed at least predominantly from a piezoelectric material, due to the reciprocal piezoelectric effect, each such functional element can be used both as a drive means, ie as an actuator and as a vibration detection sensor. This makes it possible, for example, to change the arrangement of actuators and sensors without having to change the physical position of two functional elements.

The selection of the function and the operating mode is taken over by the control or regulating device. If the functional element is subjected to an electrical voltage, it functions as a drive means or as an actuator. If the voltage is measured at the electrodes attached there, it works as a sensor.

Accordingly, an embodiment of the new vibration neutralization device according to this claim is particularly preferred. It is advantageous if, as provided according to A n s p r u c h 8, the current / voltage amplifier units are integrated into the control and regulation unit.

The invention will be explained in more detail with reference to the drawing. 1 shows a first embodiment of the vibration suppression device according to the invention, FIG. 2 shows a second type of embodiment of such a device, and FIG. 3 shows such a device having vibration-flexible functional elements. Fig. 1 shows an upper body part of a convertible 21 with a folding roof

2, where there are radiated from that rear, here left, side region 20 of the same next to the rear window 23 starting in the interior disturbing vibrations. Here, for example, only two vibration detection sensors 3 with derivatives or sensor data lines 35 are provided, via which the current / voltage signals corresponding to the vibrations emitted by the vibration detection sensors 3 as charge fluctuations, ie the sensor data to the sensor electronics or to the signal data converter 51 the control unit 5 are supplied. These are passed on to the corresponding conversion within the same to the central unit 50, where ultimately an image of the vibration and - following a respective predetermined algorithm - the calculation of a vibration compensating drive signal takes place.

The filtered sensor signal spectrum is forwarded to the actuator electronics 52, which are likewise integrated in the control and regulation unit 5, from where they are amplified to power-effective current / voltage via the actuator data line (s) 54 to the counter-vibration actuators 4. which for the impression of a - compared to the vibrations recorded by the vibration detection sensors "shifted" or "offset", vibration - thus provide a counter-vibration in the vibration-sensitive area 20 of the folding roof 2, through which generated by the turbulence of the folding roof 2 air flowing around Vibrations or vibrations of the same are "neutralized" and are thus suppressed and can no longer be heard.

For the purposes of the invention, an embodiment of the new vibration or vibration suppression device is particularly preferred in which the vibration detection sensors and the counter-vibration actuators are integrated as part of a self-sensing system or even only a functional element 3 for vibration detection and form Gegenschwingungsaufprägung, as it shows in principle the Fig. 2 with otherwise constant reference numerals meaning.

To the functional element 3, a data line 354 for the line of actuator data to the control and regulation unit 5 is connected. On the route of the same between the functional element 3 and the control and regulation unit 5, a charge tapping unit 350 is connected to this line 354 approximately in the manner of a current clamp with sensor data line 35 leading away from it. This line 35 inherently bears as information on the one hand the vibrations performed by the folding roof 2 and on the other hand the actuator data impressed by the control and regulation unit and brings those recorded data into the - as previously explained - control and regulation unit 5 from the sensor side. From the same comes the aforementioned data line 354, via which the of the

Control and regulating unit 5 submitted actuator data are forwarded to the functional element 3, which carries there for the application of counter-vibrations and thus for the neutralization of the folding roof 2 occurring vibrations in the audible frequency range care. Fig. 3 shows at otherwise constant reference numerals - schematically a section through the material (2, 201) of a motor vehicle folding roof, to which a combination of a film-like flexible sensor 3 for the registration of disturbing vibrations and delivery of corresponding sensor signals with two here via a non Such flexible-flexible, film-like sensors 3 and actuators 4, in particular on a piezo-based basis, are used, for example, by the. shown counter-vibration generator unit (51, 52, 53) to the same connected with higher voltage counter-vibration signals acted likewise foil-like flexible actuators Argillon (USA), Ceramtech (DE) or Physical Instruments (DE).

Claims

claims:

1. A device for reducing, in particular for preventing or neutralizing, at higher speeds of vehicles equipped with a textile or foil folding roof motor vehicles, in particular Cabriolets through which the folding roof umströmende air and their turbulence and / or by drive units of the vehicle od. Like., Caused and in the vehicle interior radiated, auditory frequency having, disturbing structure-borne sound vibrations or vibrations, especially in the low-frequency acoustic range, for a substantial increase in the acoustic comfort in the vehicle interior,

- Wherein at or in the for or for the occurrence of said oscillations tending discrete surface areas (20) in each case at least one mechanically deformable and correspondingly variable sensor data donating vibration ungserfassungs sensor (3) is arranged from a stimulable by vibrations functional material, which via sensor electronics (51) having at least one control and regulating unit (5) for recording, analyzing and processing or converting at least the magnitude and phase spectrum of the oscillations currently occurring in each case and detected by said sensor (3) into corresponding actuator Activation data sensor data flow is connected, and

- In which the control and regulating unit (5) in turn via their actuator electronics (52), arranged with at least one in the vicinity of the vibration detection sensors (3) by correspondingly variable actuator activation data oscillatable counter-vibration actuator (4) a vibrator-stimulable, mechanically deformable functional material aktuatordatenfluss-connected and the actuator (4) with the - specifically to the inflowing sensor vibration data phase-shifted, each having a corresponding magnitude and phase spectrum - neutralizing the vibrations of the folding roof (2) or activating counteractivating activating actuator data, characterized in that the vibration detection sensors (3) and / or the Gegenschwingungs- actuators (4) as to the extension and rapid changes in shape, in particular to the 3D surface extension and the movements, the to the vibrations or vibration adapted to stimitable portions (20) of the folding roof (2), in particular flat, variable current / voltage values as a result of the oscillations of the folding roof (2) emitting and / or stimulated as corresponding phase-shifted, variable current / voltage values in their Gegenschwingungs-generation . preferably piezoelectric, vibration detection sensors (3) and / or counter-vibration actuators (4) are formed.

2. Device according to claim 1, dad urch geken nzeich net that the vibration detection sensors (3) and / or the Gegenschwingungs- actuators (4) have a flexibility or flexibility, which substantially the flexibility or flexibility and shape change behavior of the textile - or film material (201) of the folding roof (2) corresponds.

3. Device according to claim 1 or 2, d ad urch g ekennzeichnet that the vibration detection sensors (3) and / or the Gegenschwingungs- actuators (4) and / or their Datenab- and -Zuleitungen (35, 54) to the and of the control and regulating unit (5), and possibly also the same, in the textile or film material (201) of the folding roof (2) integrated, in particular in the same or with the same entangled, are.

4. Device according to one of claims 1 to 3, d ad urch in that the, vibration detection sensors (3) and / or the Gegenschwingungs- actuators (4) each for the outgoing or discharging of - in the folding roof (2 ) currently occurring oscillations - corresponding variable current / voltage values from or for the introduction of, preferably amplified, current / voltage values for the generation of each phase-shifted negative oscillations in the, in particular textile, structure of the folding roof (2) of the Cabiolets ( 21).

5. Device according to one of claims 1 to 4, characterized in that the vibration detection sensors (3) and / or the counter-vibration actuators (4), preferably those based on piezo-ceramics, in optionally elastic, fibers, filaments and / or embedded in elastomers or elastomeric films, and these fibers, filaments or elastomers or elastomeric films themselves form the vibration or vibration-prone subregions (20) of the planar, in particular textile, structure of the folding roof (2).

6. Device according to one of claims 1 to 5, characterized in that instead of each individual or common vibration detection sensors (3) and / or counter-vibration actuators (4) based on piezoelectric materials, preferably in fibers, filaments or elastomers respectively.

Elastomer foils of the folding roof (2) or embedded on or in the folding roof,

Vibration detection sensors (3) and / or counter-vibration actuators (4)

Has basis of pyroelectric, thermoelectric, ferroelectric, magnetic, magnetorheological and / or shape memory functional materials and / or of materials based on electroactive polymers.

7. Device according to one of claims 1 to 6, characterized in that vibration detection sensors (3) and the counter-vibration actuators (4) each as responsible for the vibration detection and the counter-vibration application, common functional elements (3-4) of a self- Sensing system are formed, these functional elements (3-4) are preferably formed by piezoelectric elements.

8. Device according to one of claims 1 to 7, dad urch in that the control and regulating unit (5) comprises a current / voltage amplifier unit.