CN205613669U - Small -size inertial -type vibration exciter - Google Patents

Abstract

The utility model discloses a small inertial vibration exciter. The DC motor (1) is fixed on the chassis, and the reduction gear pair (4) installed on the output shaft of the motor transmits the power to the transmission shaft placed on the chassis. (2), the transmission shaft (2) is placed on the chassis through the bracket, and two excitation mechanisms are symmetrically arranged at its two ends; The eccentric rotor (6) rotates synchronously, the rotating shaft (3) is perpendicular to the transmission shaft (2) and is on the same horizontal plane; the power direction change is realized through the bevel gear pair (5) between the transmission shaft (2) and the rotating shaft (3) transfer. The utility model has a simple structure. While generating the excitation force required for tests such as modal measurement and dynamic performance analysis, the continuous speed control of the motor is realized by using the rotational speed of the PWM governor knob. It has the advantages of convenient control, small size and easier New features that connect to different test objects for more flexibility.

Description

Small inertial vibrator

technical field

The utility model relates to the field of vibration exciter technology and the field of dynamic experiments, in particular, it relates to the vibration exciter equipment or device used as an excitation source or providing control force in dynamic modal analysis.

Background technique

A vibrator is a device attached to certain machinery and equipment to generate excitation force. The methods used for structural excitation modal experiments can be basically divided into contact type and non-contact type. The commonly used contact exciters are mechanical, electromagnetic and electro-hydraulic. Such exciters are usually bulky and have a non-negligible mass compared to the model. During the test, it is usually placed and fixed on the ground or on the test bench, and the periodically changing exciting force is transmitted to the measured object through a rigid connecting rod, causing it to vibrate forcedly, and the measured structure is obtained through the signal collector Displacement time transformation relationship at the point, so as to carry out calculation and analysis. The connecting rods used in the above structure form additional support on the structure under test with additional stiffness and limited vibration displacement amplitude, which may easily cause errors in data collection, making it difficult for the calculation results to meet the accuracy requirements of the modal test and affect the test results.

At present, if a vibrator is used as the excitation source in the modal test experiment, most of it must be connected with the excitation object, so as to form additional stiffness and additional support for the structure under test. In some cases, the error of the modal parameters obtained in the test is relatively large. It is difficult to meet the accuracy requirements of modal testing.

Utility model content

The purpose of this utility model is to overcome the deficiencies of the existing laboratory vibrator, to provide a vibration exciter that can be adjusted in frequency, does not produce attachment stiffness and attachment damping to the structure under test, is convenient to arrange, and is suitable for structures with low stiffness and low frequency. Small inertial shaker for physical modal testing.

The technical scheme adopted by the utility model is as follows: a small inertial vibration exciter is composed of an electric power system and a mechanical excitation system. The DC motor 1 is fixed on the chassis, and the reduction gear pair 8 installed on the output shaft of the motor transmits power to the transmission shaft 2 placed on the chassis. The transmission shaft 2 is placed on the chassis through the bracket, and its two ends are symmetrical. There are two excitation mechanisms; the excitation mechanism is composed of a rotating shaft 3 standing on the chassis and an eccentric mass 6 sleeved on the rotating shaft and rotating synchronously therewith. The rotating shaft 3 is perpendicular to the transmission shaft 2 and is on the same level. Between the transmission shaft 2 and the rotating shaft 3, the power direction-changing transmission is realized through the bevel gear pair 5.

Further, a PWM DC motor speed regulating device for controlling the motor speed is arranged between the DC motor and the motor power supply.

Further, the eccentric rotors of the two excitation mechanisms are installed on the same vertical plane.

Further, a speed measuring code disc for indicating the current actual rotational speed of the rotor is installed on the rotating shaft 3 .

In this way, when working, the control system controls the DC motor, uses the gear and the transmission rod to drive the two eccentric masses with adjustable mass to rotate in reverse, and obtains a pair of equal large reverse excitations with the same natural frequency as the test object in direct contact. Vibration force for modal testing.

In a specific embodiment, the eccentric mass rotor can be embedded with an additional mass block to increase the relative magnitude of the exciting force, so as to optimize the exciting effect and make the actuator more universal.

The device provided by the utility model is small in size and light in weight, and the influence on model modal parameters can be neglected when placed on an action object. By adopting the utility model, while generating the excitation force required for tests such as modal measurement and dynamic performance analysis, the continuous speed control of the motor is realized by using the rotational speed of the PWM governor knob, which has the advantages of convenient control, small size and easier connection New features on different test objects for more flexibility.

Description of drawings

Figure 1 is a front view of the excitation system.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a left side view of Fig. 1 .

Figure 4 is a block diagram of the control system.

Fig. 5 is an external view of the adjustable mass rotor.

FIG. 6 is a sectional view of FIG. 5 .

Among the figure: 1. motor, 2. transmission shaft, 3. rotating shaft, 4. reduction gear pair, 5. bevel gear pair, 6. eccentric rotor, 7. support, 8, coupling hole, 9. support.

detailed description

The utility model will be further described below in conjunction with the accompanying drawings and examples. The implementation of the utility model includes but not limited to the following examples.

It can be seen from Figures 1-3 that the DC motor 1 in the vibration excitation system is fixed on the chassis through two fixing brackets 7, and the reduction gear pair is installed between the motor shaft and the transmission shaft 2 to cooperate with changing the maximum output speed of the motor. The transmission shaft 2 is fixed by two brackets 9 fixed on the chassis. A bevel gear pair 5 is respectively installed at both ends of the transmission shaft 2, and the transmission direction is changed with the two rotating shafts 3 to transmit a pair of equal and large reverse exciting forces. The eccentric rotor 6 is installed on the rotating shaft 3 , and the two rotating shafts are on the same horizontal plane, supported by four brackets 9 .

When the system is stationary, the center of gravity of the two eccentric rotors 6 should be adjusted to the same horizontal line by adjusting the bevel gear pair 5, and the initial phases of the two should be controlled to be the same.

It can be seen from Figure 4 that the PWM DC motor speed control device in the control system is connected between the DC motor and the motor power supply to control the motor speed.

A speed measuring code disc can be installed on the rotating shaft 3, and the output signal of the code disc is connected to the tachometer to measure the current actual speed of the rotor, which can accurately and quickly realize the frequency sweeping work in the modal test. As an improvement, the eccentric rotor is provided with coupling holes 8 with different mass blocks, and the rotor can be inserted into different mass blocks to change the excitation force, so as to adapt to models with different natural frequencies.

In the specific experiment, the assembled vibrator is placed in the center of the measured model (such as a simply supported beam model bridge deck), connected with the speed control device and the power supply system through wires, and the first-order natural frequency is obtained through theoretical calculation, and the rotor speed is adjusted. The modal test is carried out when the circular frequency reaches the theoretical natural frequency, and the first-order natural frequency and other modal parameters of the test can be obtained conveniently.

The small-scale vibrator provided by the utility model has been introduced in detail above, and specific examples have been used to illustrate the principle and implementation of the utility model. The description of the above embodiments is only used to help understand the core idea of the utility model. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made to the utility model, and these improvements and modifications also fall into the protection of the claims of the utility model. within range.

Claims (5)

1. a small-sized inertial exciter, is made up of power system and machanical vibratory extracting-driving system, It is characterized in that, direct current generator (1), by being fixed on chassis, is arranged on motor output shaft On speed reducing gear pair (4) power is sent to the power transmission shaft (2) that is placed on chassis, pass Moving axis (2) is by support with being placed on chassis, and its two ends are symmetrically arranged with two exciting agencies； Exciting agency is by the rotating shaft (3) stood on chassis and is nested with in rotating shaft and synchronous axial system therewith Eccentric rotor (6) constitute, rotating shaft (3) is vertical with power transmission shaft (2) and is in same water In plane；Realize that power becomes by bevel gear pair (5) between power transmission shaft (2) and rotating shaft (3) To transmission.

2. small-sized inertial exciter according to claim 1, it is characterised in that straight It is provided with the PWM direct current generator for controlling motor speed between stream motor (1) and motor power Arrangements for speed regulation.

3. small-sized inertial exciter according to claim 1, it is characterised in that two The eccentric rotor of individual exciting agency is arranged on same vertical plane.

4. small-sized inertial exciter according to claim 1 and 2, it is characterised in that It is provided with in rotating shaft (3) for indicating that current rotor actual speed tests the speed code-disc.

5. small-sized inertial exciter according to claim 1, it is characterised in that partially It is provided with the connection holes of configuration different quality block on heart rotor.