RION-ENG-vol7

17/24

● Arbitrary waveform (electrical signal)● Possible● Portable (supporting output from smartphone or notebook PC)● Vibration can be induced if a finger can fit into the space●●▲▲▲▲●▲100 mm or more *Approx. 200 g *76 mm in dia. × 75 mm or more * Approx. 1.1 kg *15Structural advantages of the BA-S type vibratorWith conventional BA types, the armature serves both as the magnetic and mechani­cal component. In contrast, the armature in the BA­S type vibrator functions only as a magnetic component while a spring serves as the mechanical component, which offers greater freedom in design. With conventional BA types, one end of the armature moves along an arc, while the other end is fixed. In contrast, the new type allows translational motion of the armature, making it more effective and versatile as a transducer.Comparison with other vibration sourcesThe BA­S type vibrator has a higher degree of freedom in terms of installation location, and since it can be used even in narrow spaces or on waterproof structures, diverse applications are anticipated in the future.Inducing Vibrations Where It Was Previously Not PossibleUnexpected Applications* When incased in resin designprototype cartilage conduction hearing aids. “A piezoelectric transducer doesn’t provide sufficient amplitude and involves high power consumption as it requires a driver IC,” explains Ishikawa. The structure of the BA-S type vibrator, designed to overcome all these issues, revolutionizes conventional BA-type transducers. A transducer of the BA-type will inevitably generate eccen-tric motion because one of the arma-tures is fixed and one is free to vibrate. In contrast, with the BA-S type vibrator, both ends are supported by springs, and the vibration is translational, making it a more effective and versatile transduc-er. This structure makes it possible to assemble the BA-S type vibrator into a cartilage conduction hearing air while keeping the low power consumption feature of BA-type transducers.“Another notable feature of the BA-S type vibrator compared to the BA-type,” continues Ishikawa, “is that it offers more freedom in design. When it’s ass-em bled so that the firmness of the spring and the attraction of the magnet are in balance, motion (in an ideal state) can be induced with even very weak currents. This allows the BA-S type vibrator(for example) to incorporate wide gaps between the magnet and armature to increase amplitude or to elongate in the direction of width or length.While the BA-S type vibrator was origina lly developed for use in hearing aids, Ishikawa and his team are now considering applications beyond this field. He comments, “Rion also manu-factures measuring instruments, so when we considered using the BA-S type vibrator in them, we thought it might offer potential in applications related to vibration testing. We’re cur-rently developing an exciter using the BA-S type vibrator.”An exciter is, literally, a device that induces vibration. For example, when test driving a car during automobile development, abnormal noises or vibra-tions may arise. In such cases, a vibra-tion test is done to identify the source of the abnormal vibration. Conventional vibration tests are performed by strik-ing the vehicle with an impulse ham-mer or by inducing vibrations with an exciter to study the response.“In the case of hybrid vehicles, there’s an electrical system in addition to the engine. In many cases, the interi-or of the hood is densely packed with devices,” says Ishikawa. “Sometimes, the lack of space prevents the use of an impulse hammer, or it’s impossible to place the exciter at the desired position.” One advantage of the BA-S type vibra-tor is that it’s capable of exerting a large excitation force for its size. “You can install the BA-S type vibrator under a crowded hood, for example, as long as you can get your finger inside. The abil-ity to induce vibration in tight spaces is one of its advantages.”Conventional exciters also require power amplifiers, which require stable power sources. This in turn places con-strains on measurements, such as the need for a power outlet nearby or for the weather not to be rainy during mea-surements.Exciters that use the BA-S type vibrator can be driven by a low-power source, allowing use, for example, with power delivered by the earphone jack of a smartphone.“This is what makes the BA-S type vibrator so interesting,” comments Ishi-kawa. “They allow easy measurements even at sites where no power outlets are available. And conventional exciters and impulse hammers can’t induce vibrations beneath the hood when the hood is closed. The BA-S type vibrator can, making it usable in situations where we couldn’t use such devices in the past.”In addition to application in exciters for vibration testing, Ishikawa and his team are looking forward to discover-ing applications in other fields.“The BA-S type vibrator has low power consumption. That makes it suit-able for applications previously ruled out by the lack of available power—for example, applications requiring sus-tained vibrations. Given the current global trend toward lower power con-sumption, we’re hoping the BA-S type vibrator can be used to replace conven-tional products.”Ishikawa also dreams of applica-tions beyond current thinking.“I think we might be able to make progress using the BA-S type vibrator in situations we’d previously given up on; applications we’d judged as unfeasible. I’d be delighted if information about the BA-S type vibrator were shared more widely and this lead to completely new and unprecedented applications.”*Approximate values, based on in-house researchUltra compact design and super low power consumptionHigh degree of design Allows translational 100 % waterprooffreedom movement7.8mm4.7mm11.9mmApprox. 1 g; can be attached with double-sided tapeGapTypesImpulse hammerDimensions and weightDegree of freedom of input waveformInput level adjustmentsDegree of freedom of installation locationVibrations in narrow spacesExciter (Electrodynamic type)BA-S type vibratorBB-01 (for cartilage conduction transducer) Conventional BA typeDirection of magnetizationBA-S type vibratorYokeArmatureMagnetCoilSpring