JP2009126232A - Vibration control system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control system for a vehicle achieving simple constitution and good energy efficiency in handling vibration for improving driving comfortability of an automobile. <P>SOLUTION: The vibration control system for a vehicle comprises a first transducer 2 attached to a construction member 1, 10, 11 generating vibration while driving an automobile, inputting vibration, and outputting a vibration electric signal, a second transducer 3 attached to the construction member and outputting mechanical vibration to the construction member by a driving electric signal added, and a signal processing means 4 inputting the vibration electric signal, generating the driving electric signal from the vibration electric signal, and outputting it. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle vibration control system that controls vibration generated in an automobile to improve driving comfort of the automobile.

  Conventionally, vibration in each component of an automobile has an adverse effect on driving comfort, and various vibration suppression measures have been taken. However, there is also known a technology that produces an advantage by applying vibrations to specific components of the automobile. For example, there is known a raindrop removing device including a high frequency speaker on at least one of an upper part or a side part of an outer surface of a raindrop adhesion member such as a mirror or a window glass attached outside a vehicle (for example, a patent Reference 1). This raindrop removing device pushes down water droplets staying on a mirror or glass with a large sound pressure output by operating a high-frequency speaker. In order to generate such a large sound pressure, it is necessary to prepare a corresponding power supply circuit, oscillator, high frequency generation circuit, and amplifier, which not only makes the apparatus large, but also has a problem in terms of energy efficiency.

  In addition, ultrasonic vibrators are attached to the upper and lower ends of the windshield of an automobile, and by applying an alternating current to the ultrasonic vibrator, the windshield is vibrated strongly, removing water droplets that shake off the raindrops adhering to the surface. A method is also known (see, for example, Patent Document 2). Also in this water droplet removal method, in order to drive the ultrasonic transducer, a power supply circuit, an alternating current generator, an amplifier, and the like are necessary, and the apparatus becomes large.

JP-A-8-295204 (paragraph number 0008-0021, FIG. 3) JP 2007-191129 A (paragraph numbers 0034-0036, FIG. 6 and FIG. 7)

  In view of the above circumstances, an object of the present invention is to provide a vehicle vibration control system that realizes a simple configuration and good energy efficiency when handling vibrations in order to improve driving comfort of an automobile. .

  In order to solve the above-described problems, a vehicle vibration control system according to the present invention is attached to a component of an automobile that generates vibration during operation of the automobile, and a first transducer that outputs the inputted vibration as a vibration electric signal; A second transducer that is attached to the component and converts the input drive electric signal into mechanical vibration and outputs the mechanical vibration to the component; and the vibration electric signal input from the first transducer based on the vibration electric signal. Signal processing means for generating the drive electrical signal from the oscillating electrical signal and outputting it to the second transducer.

  According to this configuration, the vibration generated in the components of the vehicle during the operation of the vehicle is captured as a vibration electrical signal, and the drive electrical signal obtained from the captured vibration electrical signal is converted into mechanical vibration. It can be applied to places that require vibration. In other words, in this vehicle vibration control system, the vibration that is the source of the final vibration output is the vibration generated in the constituent members of the automobile, and therefore the oscillation circuit that is essential in the prior art is unnecessary. In addition, when the first transducer is disposed at a place where vibration is unnecessary or where vibration is harmful, some vibration damping effect can be obtained as a secondary effect by taking out the vibration.

  In the vehicle vibration control system according to the present invention, the phase of the vibration output from the second transducer and the phase of the vibration generated in the constituent member at the mounting position of the second transducer are opposite in phase. Thus, the first transducer and the second transducer are attached to the component member. According to this feature, the mechanical vibration output from the second transducer and propagated to the component member acts to cancel the amplitude of the vibration generated in the component member at that time. Therefore, the vehicle vibration control system according to this configuration obtains the effect of damping the same component using the vibration generated in the component of the automobile as it is.

  In the vehicle vibration control system according to the present invention, the phase of the vibration output from the second transducer and the phase of the vibration generated in the constituent member at the mounting position of the second transducer are in reverse phase. Thus, the signal processing means generates the drive electrical signal. That is, the signal processing means has a phase shift function. Due to this feature, the mechanical vibration that is output from the second transducer and propagates to the component member regardless of the mounting position of the first transducer and the second transducer, the amplitude of the mechanical vibration generated in the component member at that time Can work to counteract. Therefore, the vehicle vibration control system according to this configuration obtains the effect of damping the same component using the vibration generated in the component of the automobile as it is.

  Further, in the vehicle vibration control system according to the present invention, the signal processing means further superimposes a specific high frequency converted from the frequency of the vibration electric signal on the frequency of the vibration electric signal, to thereby generate the drive electric signal. It is characterized by generating. The conversion from the frequency of the oscillating electrical signal to the specific high frequency uses a high-pass filter of a specific high frequency band by utilizing the high frequency component of the oscillating electrical signal as the center frequency. Can be adopted. It is also possible to employ a method of converting the center frequency of the vibration electrical signal. With this feature, the second transducer outputs a vibration obtained by superimposing a second vibration composed of a desired specific high-frequency component on the first vibration having the same vibration characteristics as those of the constituent members of the automobile. As a result, it is possible to obtain the effect of damping the structural member through the first vibration and the effect of removing raindrops through the second vibration. When the main purpose is raindrop removal, the signal processing means may be configured to generate the drive electrical signal by converting the frequency of the vibration electrical signal to a specific high frequency. In that case, the vibration which consists of a desired specific high frequency component can be output from a 2nd transducer, and can be propagated to a structural member, and raindrop removal is implement | achieved by the high frequency vibration. If the drive electric signal band exceeds the audible frequency range, the high-frequency vibration output from the second transducer is not perceived by the human ear, which is advantageous in terms of noise countermeasures.

  In order to output mechanical vibration having a large power from the second transducer, it is necessary to electrically amplify the vibration electric signal obtained by the first transducer to generate a drive electric signal. To this end, the vehicle vibration control system according to the present invention is further characterized in that the signal processing means is preferably provided with a positive feedback amplifier. When a positive feedback amplifier is used as the means for amplifying the oscillating electrical signal, self-excited oscillation is performed, so that amplification efficiency is good and convenient.

As described above, since the vehicle vibration control system according to the present invention can obtain both the effects of raindrop removal and vibration suppression, in particular, the first transducer and the second transducer are attached to a glass or mirror such as a window. Conveniently installed. Further, by attaching the first transducer to a bonnet or the like where a large vibration can be obtained and attaching the second transducer to the door mirror, a vehicle vibration control system that takes into account energy loss due to vibration conversion efficiency can be realized.
Further, the first transducer used in the vehicle vibration control system of the present invention converts the vibration generated in the automobile component into a vibration electric signal. Therefore, the first transducer is generated in the component. It can be used as a vibration detection sensor. Accordingly, in the vehicle vibration control system according to the present invention, as an additional function, the first transducer is attached to an automobile door including a door window, and the signal processing means knocks the vehicle door based on the vibration electrical signal. Can be detected and output as a knock detection signal based on the detection result. This knock detection signal is used as a trigger signal for unlocking the door lock or opening the door.

  In the vehicle vibration control system of the present invention, the first transducer and the second transducer are attached to components of the automobile. Also, in order to enhance the effects of raindrop removal and vibration control, it is necessary to distribute a plurality of them at appropriate positions. Accordingly, a compact transducer is preferable. For this reason, it is preferable that the first transducer and the second transducer are composed of piezoelectric elements. Furthermore, since most of the structural members of automobiles have a curved surface shape, if considering the efficiency of vibration propagation to the structural members, both transducers may have a vibration surface that can be in close contact with the curved surface shape as much as possible. is important. Accordingly, in a preferred embodiment of the present invention, the first transducer and the second transducer are composed of sheet-like flexible polymer piezoelectric elements.

  FIG. 1 shows a principle diagram of a vehicle vibration control system according to the present invention. FIG. 1 shows components of an automobile such as a bonnet, a door, a window glass, and a door mirror. This constituent member 1 is a member that generates vibration during operation of the automobile. A first transducer 2 for converting vibration generated in the component 1 into a vibration electric signal is attached to the component 1. Furthermore, a second transducer 3 that excites mechanical vibration by applying a drive signal is attached to the component 1 so that the mechanical vibration is propagated to the component 1. A signal to be given to the second transducer 3 as a drive electric signal by substantially subjecting the oscillating electric signal output from the first transducer 2 to the second transducer 3 substantially as it is or by subjecting it to electrical processing such as amplification and frequency component selection as necessary. Processing means 4 is also provided. The signal processing means 4, the first transducer 2, and the second transducer 3 constitute a vehicle vibration control system. The signal processing means 4, the first transducer 2 and the second transducer 3 are connected by a cable, and the signal processing means 4 can be attached to an appropriate member other than the component member 1.

  In FIG. 2, the vehicle vibration control system of the embodiment in which the first transducer 2 and the second transducer 3 are attached to the window glass 10 of the door 11 as the component 1 and the signal processing means 4 is attached to the door 11. It is shown. Of course, the signal processing means 4 can also be attached to the same window glass 10.

  Since the window glass 10 has a curved surface, here, the first transducer 2 and the second transducer 3 are composed of sheet-like flexible polymer piezoelectric elements. That is, the flexible polymer piezoelectric element is formed by forming the electrode layers 21 and 22 on both surfaces of the thin flexible polymer piezoelectric sheet 20 cut into a predetermined size. One of the electrode layers 21 and 22 functions as a positive electrode and the other functions as a negative electrode. A cable joined to each of the electrode layers 21 and 22 is joined, and this cable is connected to the signal processing means 4. Here, the signal processing means 4 includes an amplifier 40, which amplifies the oscillating electrical signal obtained by the first transducer 2 and generates a drive electrical signal. At this time, it is convenient to set the amplification factor of the amplifier 40 so that a drive electric signal capable of efficiently outputting mechanical vibration can be applied to the second transducer 3. If the amplifier 40 is configured as a positive feedback amplifier, it self-oscillates, which is convenient for producing a strong drive electric signal.

When the vehicle vibration control system according to the present invention is used for damping the window glass 10, the following two embodiments can be employed.
In the first embodiment, the arrangement of the first transducer 2 and the second transducer 3 is important. For example, if it is considered that the vibration of the window glass 10 acts as a plate wave, as shown in FIG. 4, the mounting interval between the first transducer 2 and the second transducer 3 is the wavelength at the resonance frequency f0 of the window glass 10. The length may be (n + 1/2) times λ0 (n is 0, 1, 2,...). Thereby, the phase of the vibration output from the second transducer 3 and the phase of the vibration generated in the window glass 10 at the mounting position of the second transducer are opposite to each other. As a result, the vibration generated in the window glass 10 at the mounting position of the second transducer is canceled by the vibration output from the second transducer, and the window glass 10 is damped.
In the second embodiment, as shown in FIG. 5, the signal processing means 4 is provided with a phase shifter 44, and the drive is performed by shifting the frequency of the oscillating electrical signal obtained by the first transducer 2 to an arbitrary position. An electrical signal is generated. At this time, the phase shift amount of the vibration electric signal shifted by the phase shifter 44 is such that the vibration phase output from the second transducer 3 by the drive electric signal is generated in the window glass 10 at the mounting position of the second transducer 3. The phase is determined so as to be opposite to the phase of the vibration. Thereby, no matter where the second transducer 3 is attached to the window glass 10, the vibration generated in the window glass 10 at the attachment position of the second transducer is selected from the second transducer 3 by selecting an appropriate phase shift amount. The window glass 10 is damped by the output vibration.

Further, in order to use this vehicle vibration control system for removing raindrops and the like attached to the window glass 10, the frequency band of the mechanical vibration output by the second transducer 3 is important. Foreign matter adhering to a flat plate such as glass can be satisfactorily shaken off by vibration in a high frequency band. For this reason, a driving electric signal in a high frequency band is applied to the second transducer 3, and mechanical vibrations in the high frequency band are output from the second transducer 3. At this time, if the high frequency band of the drive electrical signal is outside the audible frequency band, the problem that the vibration propagates to the air and becomes noise can be solved. One preferred form for generating such a high-frequency band drive electrical signal by the signal processing means 4 is schematically shown in FIG. Here, the signal processing means 4 is provided with a filter 41 as frequency conversion means for converting the frequency of the oscillating electrical signal to a specific higher frequency. If it is necessary to compensate for the loss due to filtering, an amplifier 40 may be provided. The filter 41 is a high-pass filter that passes only a specific frequency component outside the audible frequency band from the vibration frequency signal including the resonance frequency component of the window glass 10 and the high frequency component, thereby generating a drive electric signal having the specific frequency component. Is done. As the frequency converting means, not only a filter but also a frequency multiplier can be adopted.
Furthermore, it is also possible to generate a drive electric signal by superimposing a high frequency vibration converted from the vibration electric signal by the frequency conversion means on the resonance frequency vibration which is the base of the vibration electric signal. As shown in FIG. 7, in the vibration output from the second transducer 3 based on such a drive electric signal, a high frequency is superimposed on the resonance frequency. Therefore, the vibration of the window glass 10 can be controlled by the mechanical vibration of the resonance frequency output from the second transducer 3, and the raindrop removal of the window glass 10 can be performed by the mechanical vibration of the specific high frequency. Thus, a simple form for extracting the resonance frequency component and the high frequency component from the vibration electric signal is to employ a duplexer as the filter 41. This duplexer has two band-pass filters that allow the resonance frequency component of the window glass 10 and a specific high-frequency component outside the audible frequency band to pass therethrough. FIG. 8 shows a vehicle vibration control system that superimposes high-frequency vibrations converted from vibration electric signals using a frequency multiplier 45 as frequency conversion means on resonance frequency vibrations. At that time, the vibration electric signal is shifted to an appropriate phase by the phase shifter 44. Therefore, the vibration output from the second transducer 3 by the superimposed drive power signal has a damping action and a raindrop removing function at the mounting position of the second transducer.

  In the vehicular vibration control system of the embodiments so far, only one first transducer 2 and two second transducers 3 are provided in order to simplify the description. Good. For example, as schematically shown in FIG. 9, the vibration electric signals obtained from the plurality of first transducers 2 are integrated or individually processed to generate a drive electric signal, and the drive electric signal is converted into a plurality of first electric signals. 2 can be applied to the transducer 3. Thereby, vibration can be taken in from a wide range and the vibration can be applied to a wide range. Furthermore, instead of the plurality of first transducers 2, a modification in which the first transducer 2 having a configuration in which a plurality of piezoelectric elements are linear arrays is also possible. In this modification, it is also possible to finally input a vibration electric signal with a large amplitude to the signal processing means 4 by superimposing the vibration electric signals obtained from the respective piezoelectric elements by appropriately shifting the phase. .

  FIG. 10 is a block diagram showing an embodiment in which the vehicle vibration control system according to the present invention is incorporated in the door opening / closing control system 100. The door opening / closing control system 100 is a system called a smart key system, which performs authentication based on encryption communication with an approaching authentication card or the like and automatically releases the door lock. Further, in this door opening / closing control system, a door opening / closing control is adopted in which the driver who owns the authentication card approaches the car and knocks the door to be opened to release the door lock of the door. . Therefore, a sensor mechanism that detects a door knock performed on a specific door and sends a knock detection signal is required. A vehicle vibration control system according to the present invention is used for this sensor mechanism. That is, the first transducer 2 is installed so as to output a vibration electric signal in response to the vibration of the door knock generated in the door 11 or the door window 10. This vibration electric signal is transferred to the buffer 101 as a knock detection signal via the signal processing means 4. When the knock detection signal transferred to the buffer 101 is taken into the door opening / closing control system 100, the lock of the knocked door 11 is unlocked. In order to prevent erroneous operations, it may be required to distinguish between vibration caused by door knock and vibration caused by other disturbances. In that case, the vibration characteristics of the oscillating electrical signal that is output in response to the vibration of the door knock (frequency characteristics, elapsed time of vibration, etc.) and the vibration characteristics of the oscillating electrical signal that is output in response to vibration generated by something other than the door knock The signal processing means 4 may be provided with a comparator 42 relating to a specific vibration characteristic for distinguishing between the signal processing means 4 and the signal processing means 4. When the comparator 42 determines that a vibration electrical signal due to door knock has been input, the knock detection signal is transferred from the signal processing means 4 to the buffer 101.

  In the embodiment described above, the vehicle vibration control system includes the first transducer 2 that converts mechanical vibrations into electrical signals and the second transducer 3 that converts electrical signals into mechanical vibrations. However, when a piezoelectric element or the like is used, it is possible to convert a mechanical vibration into an electric signal and to convert an electric signal into a mechanical vibration with the same transducer. Accordingly, a vehicle vibration control system that includes only a single transducer that converts mechanical vibrations into electrical signals and converts electrical signals into mechanical vibrations is also within the scope of the present invention. Such a vehicle vibration control system is only schematically shown in FIG. 11, but the signal processing means 4 is provided with a time division control unit 43. One transducer 2 or 3 is operated alternately as a first transducer 2 and as a second transducer 3 by time division control.

  As a modification of this single transducer configuration, a single piezoelectric element type transducer is combined with a first piezoelectric element 20a that operates as the first transducer 2 and a second piezoelectric element 20b that operates as the second transducer 2. It is also proposed. At this time, the first piezoelectric element 20a and the second piezoelectric element 20b are preferably arranged concentrically. As the concentric arrangement, various arrangement forms such as a concentric circle arrangement as shown in FIG. 12A and a concentric rectangular arrangement as shown in FIG. 12B can be adopted.

  As described above, the vehicle vibration control system according to the present invention applies vibrations taken from the automobile structural members to desired locations through mutual conversion between mechanical vibrations and electrical signals, thereby damping the structural members. And raindrop removal with a simple configuration.

The block diagram explaining the principle of the vibration control system for vehicles by the present invention The schematic diagram explaining embodiment which applied the vibration control system for vehicles by this invention to the vibration control and raindrop removal of a door window Schematic diagram illustrating the structure of the transducer employed in the vehicle vibration control system shown in FIG. Explanatory drawing explaining arrangement | positioning of the transducer which suppresses the plate wave vibration of a door window Block diagram of signal processing means for generating a drive electric signal by shifting the frequency of the vibration electric signal Block diagram of signal processing means for selecting a frequency band and generating a drive electric signal Explanatory drawing explaining creating an output signal with resonance frequency vibration and high frequency vibration superimposed Block diagram of signal processing means for generating a drive electrical signal by superimposing a resonance frequency and a high frequency from a vibration electrical signal based on the resonance frequency Block diagram illustrating an example of a vehicle vibration control system employing a plurality of first and second transducers Schematic diagram illustrating an embodiment in which a vehicle vibration control system according to the present invention is incorporated in a door opening / closing control system. Block diagram illustrating a vehicle vibration control system employing a single transducer Illustration of a single transducer using concentric piezoelectric elements

Explanation of symbols

1: automotive component 2: first transducer 3: second transducer 4: signal processing means 10: door window (automobile component)
11: Door (component of automobile)
20: Polymer piezoelectric sheet 40: Amplifier (signal processing means)
41: Filter (signal processing means)
42: Comparator (signal processing means)
43: Time division control unit (signal processing means)
44: Phase shifter (signal processing means)
45: Frequency multiplier (signal processing means)

Claims (10)

A first transducer that is attached to a vehicle component that generates vibration during operation of the vehicle and outputs the input vibration as a vibration electrical signal;
A second transducer that is attached to the component and converts an input drive electrical signal into mechanical vibration and outputs the mechanical vibration to the component;
A vehicle vibration control system comprising: signal processing means for generating the drive electrical signal based on the vibration electrical signal input from the first transducer and outputting the generated drive electrical signal to the second transducer.   The first transducer and the second transducer so that the phase of vibration output from the second transducer and the phase of vibration generated in the component at the mounting position of the second transducer are opposite to each other. The vibration control system for vehicles according to claim 1 attached to said component.   The signal processing means outputs the drive electrical signal so that the phase of vibration output from the second transducer and the phase of vibration generated in the component at the mounting position of the second transducer are opposite to each other. The vehicle vibration control system according to claim 1 to be generated.   The said signal processing means is comprised so that the specific high frequency converted from the frequency of the said vibration electrical signal may be superimposed on the frequency of the said vibration electrical signal, and the said drive electrical signal is produced | generated. The vehicle vibration control system according to any one of the preceding claims.   The vehicle vibration control system according to claim 1, wherein the signal processing unit is configured to convert the frequency of the vibration electric signal to a specific high frequency to generate the drive electric signal.   6. The vehicle vibration control system according to claim 4, wherein the specific high frequency component is a frequency band exceeding an audible frequency.   The vehicle vibration control system according to claim 1, wherein the signal processing means includes a positive feedback amplifier.   The vehicle vibration control system according to any one of claims 1 to 7, wherein the first transducer and the second transducer are attached to glass or a mirror.   The first transducer is attached to an automobile door, and the signal processing means detects knock vibration with respect to the automobile door based on the vibration electric signal, and outputs the knock detection signal based on the detection result. The vehicle vibration control system according to any one of 1 to 7.   The vehicle vibration control system according to any one of claims 1 to 9, wherein the first transducer and the second transducer are composed of piezoelectric elements.

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