Vibration exciter is attached to some machinery and equipment to generate excitation force, is an important part of the use of mechanical vibration. The vibration exciter can make the object get a certain form and size of vibration, so as to carry out vibration and strength test on the object, or calibrate the vibration testing instrument and sensor. The vibration exciter can also be used as an excitation component to form a vibration machine, which can realize the transportation, screening, compaction, molding and tamping of soil sand and gravel. According to the different types of excitation, the exciter can be divided into inertia electric type, electromagnetic type, electro-hydraulic type, pneumatic type and hydraulic type. The exciter can produce unidirectional or multidirectional, harmonic or anharmonic excitation force.
Inertial vibration exciter
The eccentric block is used to generate the required excitation force. The inertial vibration exciter with unidirectional excitation force (Fig. 1 [schematic diagram of inertial vibration exciter with unidirectional excitation force]) is generally composed of two rotating shafts and a pair of gears with speed ratio of 1. The two shafts rotate in the opposite direction at the same speed.
Two eccentric blocks on the axis produce the resultant force of inertia force in Y direction. When working, the exciter is fixed on the excited part, and the excited part can obtain the required vibration. A self synchronous inertial vibration exciter is widely used in vibration machinery. The two shafts of the exciter are driven by two induction motors with similar characteristics, and without gears, the two shafts with eccentric blocks can rotate in the opposite direction at the same speed according to the principle of vibration synchronization, so as to obtain one-way excitation force.
Electric vibration exciter
The alternating current is fed into the moving coil to make the coil vibrate under the action of electromagnetic excitation force in the given magnetic field. The constant magnetic field of the electric vibration exciter (Fig. 2 [schematic diagram of the electric vibration exciter]) is generated by the direct current passing through the excitation coil, and then the alternating current.
Mechanical analysis of vibration exciter
When electricity is applied to the moving coil, the moving coil is affected by the periodic electromagnetic excitation force, which drives the ejector rod to make reciprocating motion. The expected vibration can be obtained by contacting the ejector rod with the excited part.
When the periodic current is input into the electromagnet coil, a periodic excitation force is generated between the excited part and the electromagnet. The electromagnetic vibration exciter used in vibration machinery (Fig. 3 [schematic diagram of electromagnetic vibration exciter]) is usually composed of an electromagnet core and an armature with a coil, and a spring is installed between the iron core and the armature. When the coil input AC, or AC plus DC, or after half wave rectification of the pulse.
When the current is applied, a periodic excitation force can be generated. Usually, the armature is fixed directly on the working part to be vibrated.
Electro hydraulic vibrator
The hydraulic servo valve is driven by a small power electric vibration exciter to control the hydraulic pressure medium in the pipeline. A great exciting force is generated on the piston in the hydraulic cylinder, so that the excited parts can obtain vibration.