机械振动控制方法.ppt

1、Control vibration in mechanism,Control vibration in transmission reasonable selection of parameters elastic supporting arranged symmetrically Reduce the vibration from source Rational arrangement of the vibration source.,Control vibration in transmission,Elastic support as a device vibration isolato

2、r Damping rubber spring washers gaskets,reasonable selection of parameters,we call it motion trainability , only when r0.707 the system has the effect of vibration isolation, . But when the system has resonance. Avoid resonance and has vibration isolation, the best way from these formula is decrease

3、d . Natural frequency is equal , m always given, Can achieve our objective from the reduction in k.,Elastic supporting arranged symmetrically,When the elastic supporting are arranged symmetrically in the four corners of the device . While when the centroid have the disturbance force on vertical dire

4、ction, the device only do vibration along vertical line or the OX axis., and does not cause other vibration on other direction.(As shown in Fig 1 (a),Compare two situation,While in Figure 1 (b), although the size of the disturbance force, the same position, and elastic supporting spots are almost in

5、 the same plane with the centroid, but the four elastic support are arranged asymmetric so that, would have vertical vibrated vibrate at the same time not only that, the device further as pitching vibration along the centroid horizontal axis (z axis). The objects has vibration in the space has six d

6、egrees of freedom, along the lines of the three coordinate axis direction , and around the three axes directions of the angular vibration. One more modes, one more natural frequency, also more time cause resonance.,Reduce the vibration from source,Consider how to satisfy the strength and functional

7、requirements but at the same time reduce the vibration when the product design begin, in order to get a good dynamic characteristics. Most of the machanism vibration is a steady-state vibration. The steady vibration usually can change the mass of the equipment or location to reduce in the steady vib

8、ration excitation. Control the vibration source is more direct and economical a way.,Rational arrangement of the vibration source.,A mass-spring system, m=1200kg, I=200kg* (Rotate by O-Y, rotating angle is ) , k=700KN /m, I= 150kg* (Rotate by O-Z, rotating angle is ), =100, F=Asin(t). O-X: O-Y: O-Z:

9、 so,Rational arrangement of the vibration source.,when the excitation source locating at point E. The maximum amplify is If vibration source device at the centroid of the machine . Each elastic support at the excitation response, only F doing vertical lines Vibration These two values is a difference of ten times. Although it is in