CN111195586A - Small eccentric vibration exciter with controllable output force - Google Patents
Small eccentric vibration exciter with controllable output force Download PDFInfo
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- CN111195586A CN111195586A CN202010085952.3A CN202010085952A CN111195586A CN 111195586 A CN111195586 A CN 111195586A CN 202010085952 A CN202010085952 A CN 202010085952A CN 111195586 A CN111195586 A CN 111195586A
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- eccentric block
- eccentric
- vibration exciter
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/10—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of mechanical energy
- B06B1/16—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of mechanical energy operating with systems involving rotary unbalanced masses
- B06B1/161—Adjustable systems, i.e. where amplitude or direction of frequency of vibration can be varied
- B06B1/162—Making use of masses with adjustable amount of eccentricity
- B06B1/164—Making use of masses with adjustable amount of eccentricity the amount of eccentricity being automatically variable as a function of the running condition, e.g. speed, direction
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- Apparatuses For Generation Of Mechanical Vibrations (AREA)
Abstract
The invention belongs to the field of mechanical automation, and relates to a small eccentric vibration exciter with controllable output force, which can be used for structural dynamics experiments in mechanics. The vibration exciter of the invention mainly comprises two sets of symmetrical devices, wherein each set comprises a stepping motor, a motor frame, two eccentric blocks, a sleeve, a gasket, a hand-screwed screw and a dial. The invention can change the magnitude of the output dynamic load by adjusting the included angle of the two eccentric blocks, so that the output dynamic load can not change along with the change of the frequency any more, and the purpose can be achieved by loosening and screwing the hand-screwed screw, thereby being convenient and fast. Compared with the traditional electromagnetic vibration exciter, the vibration exciter is directly placed on a structure and is not connected with other foundations, so that the stroke of a loading point of the structure is not limited; compared with the traditional eccentric vibration exciter, the invention can control the amplitude of the output dynamic load and overcome the defect that the amplitude of the output dynamic load of the traditional eccentric vibration exciter is increased along with the increase of the frequency.
Description
Technical Field
The invention belongs to the field of mechanical automation, and relates to a small eccentric vibration exciter with controllable output force, which can be used for structural dynamics experiments in mechanics.
Background
The structure dynamics is an important branch in the field of mechanics, and has important application in the fields of civil engineering, mechanical engineering, aerospace and the like. "resonance" is the most fundamental point of knowledge in structural dynamics, which can be expressed as, for example, the fundamental single degree-of-freedom system: when the single-degree-of-freedom system is subjected to dynamic load action of different parameters, if the dynamic load amplitude is unchanged, in the process that the load frequency is increased from zero to the basic frequency of the structure, the structure dynamic displacement amplitude is increased along with the increase of the load frequency and reaches the maximum at a resonance point, and then the structure dynamic displacement amplitude is reduced along with the increase of the load frequency until the structure dynamic displacement amplitude approaches to zero.
The demonstration experiment of the relation between the structure dynamic displacement amplitude and the dynamic load frequency comprises the following steps: firstly, the amplitude of a dynamic load is specified, for example, 5N; secondly, measuring the fundamental frequency of the structure; then measuring the displacement of the structure under the static load with the size of 5N as the displacement when the dynamic load frequency is zero; then keeping the dynamic load amplitude unchanged, gradually increasing the load frequency to infinity (generally reaching 5 times of the natural frequency of the structure), and respectively measuring the dynamic displacement amplitudes of the structure under the same load amplitude and different load frequencies; and finally, drawing a relation curve of the structure dynamic displacement amplitude and the load frequency by taking the ratio of the load frequency to the basic frequency of the structure as an abscissa and the dynamic displacement amplitude of the structure under different load frequencies as an ordinate.
In order to achieve the purpose of experiment, a loading device capable of adjusting the load frequency and ensuring the amplitude of the dynamic load to be unchanged is needed. At present, when a demonstration experiment of the relation between the structural dynamic displacement amplitude and the dynamic load frequency is generally carried out, the adopted loading equipment comprises a vibrating table, an electromagnetic vibration exciter and the like, the loading equipment can output the dynamic load with fixed frequency, but the loading equipment cannot accurately control the amplitude of the output dynamic load, the amplitude of the output dynamic load can be obtained only through subsequent measurement and then is converted in proportion, the stroke of the traditional electromagnetic vibration exciter is limited, and vibration excitation cannot be carried out at any point of the structure, so that the loading equipment cannot achieve a sufficient visual effect in the teaching demonstration experiment.
Disclosure of Invention
In order to solve the problems that the dynamic load amplitude and the stroke are insufficient and cannot be accurately controlled by the loading equipment, the invention provides the small eccentric vibration exciter with controllable output force, and aims to demonstrate an experiment of the relation between the structural dynamic displacement amplitude and the dynamic load frequency.
The technical scheme of the invention is as follows:
a small eccentric vibration exciter with controllable output force mainly comprises a stepping motor 1, a motor frame 2, an eccentric block a4, an eccentric block b5, a sleeve 6, a hand-screwed screw 8 and a dial 9;
the stepping motors 1 are symmetrically fixed at the bottom of the motor frame 2 through fixing screws 3, and motor shafts of the stepping motors 1 vertically and upwards penetrate through the motor frame 2 and are positioned in the motor frame 2; the number of the sleeves 6 is two, the lower parts of the two sleeves 6 are respectively arranged on the motor shafts of the two stepping motors 1, and the upper parts of the two sleeves are higher than the top ends of the motor shafts; each sleeve 6 is sleeved with an eccentric block a4 and an eccentric block b 5; the dial 9 is fixedly arranged on the upper surface of the eccentric block a4, the dial 9 is positioned above the eccentric block a4 and the eccentric block b5, the circular dial 9 is coaxial with a motor shaft of the stepping motor 1, and the included angle of the eccentric block a4 and the eccentric block b5 in the horizontal direction is obtained through the dial 9; the inner wall of the upper part of the sleeve 6 is provided with threads, a gasket 7 is sleeved on a hand screw 8, the hand screw 8 is screwed into the sleeve 6 from the top, and the sleeve 6, the eccentric block a4 and the eccentric block b5 are fixed into a whole by extrusion friction force generated by screwing the hand screw 8.
When the included angle between the eccentric block a4 and the eccentric block b5 is adjusted, the hand screw 8 is loosened, the included angle between the eccentric block a4 and the eccentric block b5 is adjusted to a required angle according to the index of the dial 9, and then the hand screw 8 is tightened.
The invention can change the magnitude of the dynamic load output by adjusting the included angle between the eccentric block a4 and the eccentric block b5, so that the dynamic load output can not change along with the change of frequency any more, and the purpose can be achieved by loosening and tightening the hand-screwed screw 8, thereby being convenient and rapid.
The invention has the beneficial effects that:
compared with the traditional electromagnetic vibration exciter, the vibration exciter is directly placed on a structure and is not connected with other foundations, so that the stroke of a loading point of the structure is not limited; compared with the traditional eccentric vibration exciter, the invention can control the amplitude of the output dynamic load and overcome the defect that the amplitude of the output dynamic load of the traditional eccentric vibration exciter is increased along with the increase of the frequency.
Drawings
Fig. 1 is a front elevation view of a small eccentric type vibration exciter of which output force is controllable according to the present invention.
Fig. 2 is a plan view of a small eccentric type vibration exciter of which output force is controlled according to the present invention.
In the figure: 1 step motor, 2 motor frames, 3 fixed screws, 4 eccentric blocks a, 5 eccentric blocks b, 6 sleeves, 7 gaskets, 8 hand-screwed screws and 9 dials.
Detailed Description
The following further describes a specific embodiment of the present invention with reference to the drawings and technical solutions.
As shown in fig. 1 and 2, the small eccentric vibration exciter with controllable output force of the present invention mainly comprises a stepping motor 1, a motor frame 2, a fixing screw 3, an eccentric block a4, an eccentric block b5, a sleeve 6, a gasket 7, a hand screw 8 and a dial 9.
The installation mode of the device of the invention is as follows:
two stepping motors 1 are fixed at the bottom of a motor frame 2 through 8 fixing screws 3, a sleeve 6 is sleeved on a motor shaft of the stepping motor 1, an eccentric block a4 is firstly sleeved on the sleeve 6, an eccentric block b5 is sleeved on the sleeve 6, an eccentric block a4 is arranged below, an eccentric block b5 is arranged above, and the included angle between the two eccentric blocks can be freely adjusted. The dial 9 is adhered to the upper surface of the eccentric block a4 by glue or double-sided adhesive tape, the dial 9 is coaxial with the motor shaft of the stepping motor 1, and the dial 9 is not adhered to the eccentric block b 5.
Sleeving a gasket 7 on a hand-screwed screw 8, wherein the upper surface and the lower surface of the gasket 7 are respectively contacted with the hand-screwed screw 8 and an eccentric block; the hand screw 8 is screwed into the thread of the sleeve 6 and tightened, and the sleeve 6, the eccentric mass a4 and the eccentric mass b5 are fixed together by the pressing friction force generated by tightening the hand screw 8, and the washer 7 functions to protect the pressing surface.
When adjusting the contained angle between two eccentric blocks, loosen hand screw 8, adjust the contained angle of two eccentric blocks to required angle through the reading of calibrated scale 9, tighten hand screw 8 again.
The mode of controlling the output force of the invention is as follows:
according to Newton's second law, the rotation of the eccentric mass around the central axis applies a centrifugal force to the central axis, which is directed from the axis of rotation to the center of mass of the eccentric mass, the magnitude of this force being related to the mass, eccentricity and angular velocity of the eccentric mass; the direction is always from the rotating shaft to the mass center of the eccentric block. The centrifugal force generated when the eccentric block rotates can be expressed by the following formula:
F＝m·2r
in the formula: f is the centrifugal force generated when the eccentric block rotates;
angular velocity of the eccentric mass rotation;
r is the eccentricity of the eccentric block to the central shaft.
Because the centrifugal force direction generated by the single motor and the eccentric block always points to the mass center of the eccentric block from the rotating shaft, namely a circle in a plane, and the dynamic load required by the experiment is in a single direction, the invention adopts the design of two sets of motors and eccentric blocks: when the vibration exciter is used, the vibration exciter is directly placed on a structure, two sets of eccentric blocks on two stepping motors 1 are adjusted to be completely symmetrical (the included angles of the two sets of eccentric blocks are the same, the initial phases are also the same) in an initial state, then the two stepping motors 1 are enabled to move reversely when in work, and because the dynamic loads generated by the two sets of eccentric blocks are the same in magnitude and are all directed to the mass center of the eccentric block from a rotating shaft at the same time and are symmetrical about the central axis of the two motors, the symmetrical centrifugal forces generated by the two sets of eccentric blocks are mutually offset in other directions, and only the force in the direction of the central axis of the two stepping motors. Finally, the dynamic load output by the vibration exciter of the invention is a sine function which changes along with time, the frequency is the same as the rotation frequency of the motor, and the amplitude is the sum of the centrifugal force generated by the two sets of eccentric blocks.
According to the invention, the eccentric distance of the eccentric blocks is changed by loosening the hand-screwed screws 8 and manually adjusting the included angle between the two eccentric blocks according to the dial 9, and the magnitude of the eccentric force output by the eccentric blocks under different rotating speeds and different included angles of the eccentric blocks can be obtained through calculation, for example: when the output eccentric force is controlled to be constant at 2N, the included angle of the eccentric block corresponding to the motor frequency of 2Hz is 114.5 degrees; the motor frequency is 3Hz, and the included angle of the eccentric block is 152.2 degrees; the motor frequency is 4Hz, which corresponds to the eccentric block included angle of 164.4 degrees.
Claims (2)
1. The small eccentric vibration exciter with controllable output force is characterized by mainly comprising a stepping motor (1), a motor frame (2), an eccentric block a (4), an eccentric block b (5), a sleeve (6), a hand-screwed screw (8) and a dial (9);
the two stepping motors (1) are symmetrically fixed at the bottom of the motor frame (2) through fixing screws (3), a motor shaft of each stepping motor (1) vertically and upwards penetrates through the motor frame (2), and the motor shaft is positioned in the motor frame (2); the number of the sleeves (6) is two, the lower parts of the two sleeves (6) are respectively arranged on the motor shafts of the two stepping motors (1), and the upper parts of the two sleeves are higher than the top ends of the motor shafts; each sleeve (6) is sleeved with an eccentric block a (4) and an eccentric block b (5); the dial (9) is fixedly installed on the upper surface of the eccentric block a (4), the dial (9) is located above the eccentric block a (4) and the eccentric block b (5), the circular dial (9) is coaxial with a motor shaft of the stepping motor (1), and an included angle between the eccentric block a (4) and the eccentric block b (5) in the horizontal direction is obtained through the dial (9); the inner wall of the upper part of the sleeve (6) is provided with threads, the hand-screwed screw (8) is sleeved with the gasket (7), the hand-screwed screw (8) is screwed into the sleeve (6) from the top, and the sleeve (6), the eccentric block a (4) and the eccentric block b (5) are fixed into a whole by the extrusion friction force generated by screwing the hand-screwed screw (8).
2. The small eccentric vibration exciter with controllable output force according to claim 1, characterized in that when the included angle between the eccentric block a (4) and the eccentric block b (5) is adjusted, the hand screw (8) is loosened, the included angle between the eccentric block a (4) and the eccentric block b (5) is adjusted to a required angle according to the index of the dial (9), and then the hand screw (8) is tightened.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010085952.3A CN111195586A (en) | 2020-02-11 | 2020-02-11 | Small eccentric vibration exciter with controllable output force |
| PCT/CN2020/119805 WO2021159720A1 (en) | 2020-02-11 | 2020-10-05 | Small eccentric vibration exciter having controllable output force |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010085952.3A CN111195586A (en) | 2020-02-11 | 2020-02-11 | Small eccentric vibration exciter with controllable output force |
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| CN111195586A true CN111195586A (en) | 2020-05-26 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010085952.3A Pending CN111195586A (en) | 2020-02-11 | 2020-02-11 | Small eccentric vibration exciter with controllable output force |
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| CN (1) | CN111195586A (en) |
| WO (1) | WO2021159720A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021159720A1 (en) * | 2020-02-11 | 2021-08-19 | 大连理工大学 | Small eccentric vibration exciter having controllable output force |
| CN113385412A (en) * | 2021-07-21 | 2021-09-14 | 山东理工大学 | Circular vibration relaxation sieve with online adjustable exciting force and exciting force adjusting method |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3410449A1 (en) * | 1984-03-22 | 1985-09-26 | Uhde Gmbh, 4600 Dortmund | Unbalanced oscillatory drive |
| DE3515690C1 (en) * | 1985-05-02 | 1986-09-11 | Gebr. Lindenmeyer GmbH & Co Maschinenfabrik, 8906 Gersthofen | Vibrationsbaer with unbalance adjustment |
| CN2239298Y (en) * | 1995-04-11 | 1996-11-06 | 包头市永磁电机研究所 | Exciter |
| CN2413805Y (en) * | 1999-12-03 | 2001-01-10 | 西安建筑科技大学 | Reversal vibration exciter |
| CN2616310Y (en) * | 2003-03-07 | 2004-05-19 | 江群峰 | Reverse synchronous vibrating apparatus |
| CN201699516U (en) * | 2010-05-27 | 2011-01-05 | 卧龙电气集团股份有限公司 | Exciting force adjusting device of vibration motor |
| CN104259084B (en) * | 2014-07-31 | 2016-06-01 | 中国船舶重工集团公司第七一一研究所 | A kind of active damping device vibrator |
| CN111195586A (en) * | 2020-02-11 | 2020-05-26 | 大连理工大学 | Small eccentric vibration exciter with controllable output force |
-
2020
- 2020-02-11 CN CN202010085952.3A patent/CN111195586A/en active Pending
- 2020-10-05 WO PCT/CN2020/119805 patent/WO2021159720A1/en active Application Filing
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021159720A1 (en) * | 2020-02-11 | 2021-08-19 | 大连理工大学 | Small eccentric vibration exciter having controllable output force |
| CN113385412A (en) * | 2021-07-21 | 2021-09-14 | 山东理工大学 | Circular vibration relaxation sieve with online adjustable exciting force and exciting force adjusting method |
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| Publication number | Publication date |
|---|---|
| WO2021159720A1 (en) | 2021-08-19 |
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