JP2739599B2 - Noise reduction device for vibration transfer machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for effectively reducing noise generated during operation of a vibration transfer machine suitable for transfer of, for example, small castings and molding sand.

2. Description of the Related Art In a vibratory transfer machine configured to transfer an object to be conveyed by rotation of an eccentric drive shaft of a vibration system and reciprocation of a trough synchronized with rotation of the eccentric drive shaft, a trough having a large area is used. It is known that air vibration is generated due to the reciprocation of the air, and noise (90 dB at a position 1 m on the machine side) due to the air vibration is generated.

Moreover, even in the case of the same type of vibration carrier, there is a very small difference in the actual number of revolutions of each eccentric drive shaft. In the region where the displacement angular phase of the eccentric drive shaft matches due to the difference, a high-level noise exceeding 100 dB (ultra-low frequency noise) is generated due to the resonance phenomenon. As a result, vibration disturbances that increase psychological and physiological discomfort, and also damage buildings and deteriorate the environment occur.

[Problems to be Solved by the Invention] As a means for coping with such a situation, a soundproof wall having extremely high rigidity is generally constructed to block sound, but this requires a large construction space and expensive construction costs. In addition to being economically disadvantageous, there is a problem that effective sound insulation cannot be expected because of not having a function of actively reducing noise.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and a noise reduction device for a vibration transfer device capable of achieving compactness and cost reduction with simplification of the configuration and capable of positively reducing noise. The purpose is to provide.

[Means for Solving the Problems] To achieve the above object, the present invention provides at least one
A pair of displacement angle detecting means for detecting a displacement angle of the eccentric drive shaft of each of the pair of vibration transfer machines; and a displacement angle of the other eccentric drive shaft with respect to the detected displacement angle of one of the eccentric drive shafts. Phase difference setting means for setting an arbitrary phase difference; and calculating means for receiving a detection signal from the two displacement angle detecting means, calculating a shift amount between the set phase difference and the actual phase difference, and outputting a correction signal. And control means for outputting a rotation control signal to a drive motor for one of the eccentric drive shafts selected based on the correction signal from the calculation means.

[Operation] According to the present invention, the displacement angle of one eccentric drive shaft detected by one displacement angle detecting means is shifted by 180 ° by the phase difference setting means by the phase angle setting means. Set to lag phase. Then, detection signals from both displacement angle detecting means are input to the calculating means.

The calculating means calculates a difference between the set phase difference and the actual phase difference between the displacement angle input from one displacement angle detecting means and the displacement angle input from the other displacement angle detecting means. The control signal output from the control means controls the rotation of the drive motor for the other eccentric drive shaft, and outputs the correction signal by 180 degrees with respect to the rotation angle of one eccentric drive shaft. Vibration is reduced by providing a phase difference.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic front view showing an example of a vibration transfer machine to which the apparatus of the present invention is applied, and FIG. 2 is a schematic side view thereof. In these figures, the vibration transfer machine 1 has an eccentric drive shaft of a vibration system 2. 3
And the reciprocating motion of the trough 4 synchronized with the rotation of the eccentric drive shaft 3 to convey the load. That is, the eccentric drive shaft 3 to which the pulley 5 is fixed at one end is rotatably and horizontally supported by the bearings 6,6. A bracket 7 is attached to the lower surface of the trough 4, and a horizontal bar 9 having elastic members 8, 8 made of rubber or the like disposed on both side ends, is mounted on the bracket 7.

The eccentric drive shaft 3 and the horizontal bar 9 are connected to each other by a connecting rod 10. Therefore, the eccentric drive shaft 3 is driven by the motor 11 via the belt 12.
Is rotated, the trough 4 reciprocates by a stroke amount corresponding to the amount of eccentricity of the eccentric drive shaft 3 and conveys the conveyed object.

For example, as shown in FIG. 3, two such vibration transfer machines 1 are installed side by side in a state where the same types are relatively close to each other. For convenience of explanation, one vibration carrier 1 and the other vibration carrier 1A are denoted by reference numerals, and the eccentric drive shaft 3 is also distinguished by one eccentric drive shaft 3 and the other eccentric drive shaft 3A. Assign a sign.

The eccentric drive shafts 3, 3A are connected to displacement angle detecting means 15, 15A via well-known synchronous rotation transmitting means 13, 13 constituted by a timing pulley and a timing belt, and helical couplings 14, 14, respectively. Therefore, one displacement angle detecting means 15 detects the displacement angle θ1 when one eccentric drive shaft 3 rotates, and the other displacement angle detecting means 15A detects the displacement angle θ2 when the other eccentric drive shaft 3A rotates. Will be.

The phase difference setting means 16 sets the detected displacement angle θ1 of one eccentric drive shaft 3 to the displacement angle θ2 of the other eccentric drive shaft 3A.
This is for setting a phase difference θx of 180 degrees, and is electrically connected to both displacement angle detecting means 15, 15A. Numeral 17 denotes arithmetic means, which is, for example, a thyristor inverter. In this arithmetic means 17, the set phase difference θx set by the phase difference setting means 16, the displacement angle θ1 input from one displacement angle detecting means 15, and the other The amount of deviation of the displacement angle θ2 input from the displacement angle detection means 15A from the actual phase difference is calculated,
A correction signal corresponding to the amount of deviation is output to the control means 18, and a rotation control signal is output from this to the drive motor 11A of the other eccentric drive shaft 3A.

In the above configuration, when the vibration transfer machines 1 and 1A are operated at the same time, the displacement angle θ1 of one eccentric drive shaft 3 detected by one displacement angle detection unit 15 is changed by the displacement of the other eccentric drive shaft 3A. The angle θ2 is set by the phase difference setting means 16 to a leading phase or a lagging phase θx of 180 degrees. Then, the detection signals from the displacement angle detecting means 15 and 15A are input to the calculating means 17.

The calculating means 17 calculates the difference between the set phase difference θx and the actual phase difference between the displacement angle θ1 input from the one displacement angle detecting means 15 and the displacement angle θ2 input from the other displacement angle detecting means 15A. Is done. Then, a correction signal corresponding to the amount of deviation is output to the control means 18, and the control signal output from the control means 18 controls the rotation of the drive motor 11A of the other eccentric drive shaft 3A, and the other eccentric drive The rotation angle θ2 of the shaft 3A is synchronized with the rotation angle θ1 of the one eccentric drive shaft 3 by providing a leading phase or a lagging phase difference θx of 180 degrees.
As a result, the troughs 4 of the two vibration transfer machines 1 and 1A are reciprocated in opposite phases, so that air vibrations are canceled out and the noise is positively reduced.

As a result, even if the same type of vibration transfer machine 1, 1A with a very small difference in the actual rotation speed of each eccentric drive shaft 3, 3A is installed relatively close, 100 dB due to the resonance phenomenon as in the past High-level noise (extremely low-frequency noise) exceeding 90 dB can be reduced to 90 dB or less, which is equivalent to the noise level of one vibration carrier 1. Therefore, psychological and physiological discomfort can be reduced, and a vibration disturbance that damages the building and deteriorates the environment is avoided. Moreover, downsizing and cost reduction due to simplification of the configuration can be realized.

In the above embodiment, the displacement angle θ2 of one eccentric drive shaft 3A detected by the one displacement angle detection means 15 and the displacement angle θ2 of the other eccentric drive shaft 3A are detected by the phase difference setting means.
Although the description has been made so that the phase is set to the 180-degree leading phase or the lagging phase θx by 16, the present invention is not limited to the above embodiment, and the other displacement angle detecting means 15A is used.
With respect to the displacement angle θ2 of the other eccentric drive shaft 3A detected by the above, the displacement angle θ1 of the one eccentric drive shaft 3 is set to 180 ° advance phase or lag phase θx by the phase difference setting means 16. Also, the same operation and effect as those of the above embodiment can be obtained.

[Effects of the Invention] As described above, the present invention provides a pair of displacement angle detecting means for detecting a displacement angle of an eccentric drive shaft of each of at least one pair of vibration transfer machines, and one of the detected eccentricities. Phase difference setting means for setting the displacement angle of the other eccentric drive shaft to an arbitrary phase difference with respect to the displacement angle of the drive shaft; detection signals from the two displacement angle detection means are input to set the phase difference and the actual position; Calculating means for calculating the amount of deviation from the phase difference and outputting a correction signal; and control for outputting a rotation control signal to a driving motor for one of the eccentric drive shafts selected based on the correction signal from the calculating means. Therefore, even if the same type of vibrating conveyance machine having an extremely small difference in the actual number of rotations of the eccentric drive shaft is installed relatively close, a high level due to the resonance phenomenon as in the related art Noise (ultra low frequency noise) by one unit It can be positively reduced to below the noise level of the transporter. Therefore, psychological and physiological discomfort can be reduced, and a vibration disturbance that damages the building and deteriorates the environment is avoided. Moreover, there is an effect that the cost can be reduced and the economical advantage can be secured by the compactness accompanying the simplification of the configuration.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing an example of a vibration transfer machine to which the apparatus of the present invention is applied, FIG. 2 is a schematic side view of the same, and FIG. 1,1A ... Vibration transfer machine, 2 ... Vibration system, 3,3A ... Eccentric drive shaft, 4 ... Trough, 11,11A ... Drive motor, 15,15A ...
... displacement angle detecting means, 16 ... phase difference setting means, 17 ... calculating means, 18 ... control means, θ1, θ2 ... displacement angle, θx ...
Phase difference.

Claims (1)

(57) [Claims] 1. A noise reduction device for a vibration transfer machine for transferring an object to be conveyed by rotation of an eccentric drive shaft of a vibration system and reciprocation of a trough synchronized with rotation of the eccentric drive shaft, comprising at least one pair of vibrations. A pair of displacement angle detecting means for detecting a displacement angle of the eccentric drive shaft of each of the transfer machines; and an arbitrary displacement angle of the other eccentric drive shaft with respect to the detected displacement angle of one of the eccentric drive shafts. Phase difference setting means for setting the phase difference; calculating means for receiving the detection signals from the displacement angle detecting means to calculate the amount of deviation between the set phase difference and the actual phase difference and outputting a correction signal; Control means for outputting a rotation control signal to a drive motor of one of the eccentric drive shafts selected based on a correction signal from the means.