CN100358005C - Control system for active noise of hydraulic pump - Google Patents

Abstract

The invention discloses an active noise control system for a hydraulic pump. The system includes a sound insulation cover, a muffler, a control source, a microphone, a tachometer and a multi-channel self-adaptive active controller, which can better control the hydraulic pump. The noise component above 600HZ can also better control the noise component of the hydraulic pump below 600Hz. The degree of automation is high, and the sound insulation effect of low frequency is good. Compared with the noise reduction effect of the traditional sound insulation cover, it can maintain the original sound insulation cover Under the condition of a smaller volume, its low-frequency noise reduction performance is increased; at the same time, it is less affected by the installation space on site, and can reduce the volume of the sound insulation cover used while maintaining the sound insulation and noise reduction performance.

Description

Active Noise Control System for Hydraulic Pumps

1. Technical field

The invention relates to a noise control system, in particular to a noise control system of a hydraulic pump.

2. Background technology

The hydraulic pump is the power source in the liquid transmission system, which produces two types of noise: one is liquid dynamic noise, and the other is mechanical noise. The more polluting noise is concentrated in the low frequency. The "Noise and Vibration Control Engineering Handbook" published by the Mechanical Industry Press in 2002 discloses the use of a sound insulation cover to seal the hydraulic pump, thereby reducing the hydraulic pump by using the sound insulation function of the sound insulation material and the sound absorption function of the lining sound absorption material. A hydraulic pump noise control method for surrounding noise pollution. This technology uses a fully enclosed sound insulation cover to isolate the noise radiation of the hydraulic pump, but it also brings ventilation and heat dissipation problems. The current solution is to introduce a muffler to solve the ventilation and heat dissipation problems, but the result is Low frequency noise is not well controlled. In this case, the problem of insufficient low-frequency sound insulation can only be solved by thickening the thickness of the sound insulation cover and increasing the length of the muffler, which will inevitably lead to an increase in the volume of the sound insulation cover. However, under certain site conditions, especially when the surrounding space environment is complex and the facilities are relatively tight, the surrounding space does not allow the volume of the sound insulation cover to be too large, so that it is impossible to increase the volume of the sound insulation cover and improve the insulation performance. sound effects. Therefore, the disadvantages of this noise control scheme using the sound insulation cover are: 1. The low-frequency noise control effect of the hydraulic pump is not good; 2. It is limited by the surrounding installation space in actual use.

The development of modern electronic technology, signal processing, control theory and transducer technology makes active noise control system widely used in the field of noise control. At present, the active control systems that have been practical include: active anti-noise earmuffs, active noise control in pipelines, active noise control in aircraft and car cabins, and active control of transformer single-frequency noise. There are no systems that combine active noise control systems with traditional acoustic enclosures. "Experimental Research on Active Control of Exhaust Noise of a Highly Intensified Diesel Engine" published in "Noise and Vibration Control" Issue 2, 2001, Page 6-8, and "Journal of Nanjing University of Aeronautics and Astronautics", Issue 35, 2003 "Simulation Experimental Research on Adaptive Internal Model Control of Helicopter Cabin Noise" on pages 253-257 of the issue discloses active noise control technology in terms of active control of sound input and active control in pipelines and small volume spaces However, there is no precedent of applying the active noise control system to the sound insulation enclosure system of the hydraulic pump at home and abroad.

3. Contents of the invention

1. Purpose of the invention: The purpose of the invention is to provide a hydraulic pump noise control system with good low-frequency sound insulation effect and little influence from installation space conditions.

2. Technical solution: In order to achieve the purpose of the above invention, the hydraulic pump active noise control system of the present invention includes a sound insulation cover, and a muffler is arranged on the sound insulation cover. The system also includes a control source, a microphone, a tachometer and a multi-channel automatic noise control system. Adaptive active controller, wherein the tachometer is installed on the shaft of the hydraulic pump, the multi-channel adaptive active controller is arranged outside the sound insulation enclosure, and the control source, microphone and tachometer are respectively connected with the multi-channel adaptive active controller Connection; the control source is distributed above and around the hydraulic pump, and should be installed close to the hydraulic pump. The closer the distance, the better the control effect of the system on the low-frequency line spectrum component of the noise.

The control source can be a loudspeaker, an exciter, or an electromagnetic driver.

The microphone can adopt an electret microphone, and the electret microphone can be improved according to the site conditions.

The sound insulation cover and the muffler in the hydraulic pump active noise control system of the present invention are mainly aimed at the medium and high frequency noise of the hydraulic pump.

Other devices in the hydraulic pump active noise control system of the present invention specifically control the low-frequency line spectrum components of the hydraulic pump noise. The tachometer is installed on the shaft of the hydraulic pump to obtain the speed information, and the microphone is placed in the soundproof enclosure to obtain the sound field information in the enclosure. The information of these sensors is fed into the multi-channel adaptive active controller, and then the multi-channel adaptive active controller The source controller generates corresponding control signals to drive the control source, and the control source starts to work to reduce the radiation of the low-frequency line spectrum component of the hydraulic pump.

The principle of the present invention is: the traditional sound insulation cover has a better control effect on the noise component above 600 Hz of the hydraulic pump, but for the noise component of the hydraulic pump below 600 Hz, although the sound insulation cover and the muffler still have a certain effect on the low frequency noise, However, due to the characteristics of low-frequency sound waves of noise, its sound insulation effect at low frequencies is relatively poor in general, and cannot meet the sound insulation indicators required in practice. The active system part of the present invention is specially aimed at the noise component below 600Hz. After the noise signal is obtained by the microphone, the active adaptive controller sends a control signal to the speaker to drive the speaker to work, thereby reducing the low-frequency line spectrum of the hydraulic pump. weight purpose.

3. Beneficial effects: the present invention has the following advantages: (1) The low-frequency sound insulation effect is good. Compared with the noise reduction effect of the traditional sound insulation cover, it can increase its low-frequency noise reduction under the condition of maintaining the volume of the original sound insulation cover. (2) It is less affected by the installation space on site, and can reduce the volume of the sound insulation cover used while maintaining the sound insulation and noise reduction performance.

4. Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a top view of Fig. 1 , for clarity, the speaker above the hydraulic pump is omitted in the figure.

5. Specific implementation

Embodiment 1: Measure the noise of the hydraulic pump to be controlled. If the main noise spectrum covers a wider frequency band, the traditional sound insulation cover needs a larger volume or the low-frequency noise reduction effect is not good, then the present invention should be used .

Firstly, measure the required noise reduction and its frequency band for the noise of the hydraulic pump, and then use the measured data to optimize the position and number of microphones and control sources. The optimization method used can be found in "Adaptive Active Noise Control-Principle, Algorithm and Realization" published by Northwestern Polytechnical University Press in 1993 and "Noise and Vibration Control Engineering Handbook" published by Mechanical Industry Press in 2002.

As shown in Figures 1 and 2, the hydraulic pump active noise control system of this embodiment includes a sound insulation cover 1, and a muffler 2 is arranged on the sound insulation cover 1. The system also includes a control source 3, a microphone 4, and a tachometer. 5 and a multi-channel self-adaptive active controller 6, the tachometer 5 is installed on the rotating shaft of the hydraulic pump 7, the multi-channel self-adaptive active controller 6 is arranged outside the sound insulation cover 1, and the control source 3, the microphone 4 and the tachometer 5 are respectively connected with the multi-channel self-adaptive active controller 6, and the connection circuit adopts the existing technology;

The control source 3 adopts speakers, the number of which is 8, and are evenly distributed above and around the hydraulic pump 7, wherein two speakers are located above the hydraulic pump 7, and the remaining 6 are evenly distributed around the hydraulic pump 7;

The microphone 4 is an electret microphone, the number of which is 8, and is installed in the sound insulation cover 1 .

Claims (5)

1. An active noise control system for a hydraulic pump, comprising a sound insulation cover (1), and a muffler (2) is arranged on the sound insulation cover (1), and it is characterized in that: the system also includes a control source (3), a microphone ( 4), tachometer (5) and multi-channel self-adaptive active controller (6), wherein, tachometer (5) is installed on the rotating shaft of hydraulic pump (7), control source (3), microphone (4) and The tachometer (5) is respectively connected with the multi-channel self-adaptive active controller (6) located outside the sound insulation cover (1); the control source (3) is distributed above and around the hydraulic pump (7). 2. The hydraulic pump active noise control system according to claim 1, characterized in that the control sources (3) are evenly distributed above and around the hydraulic pump (7). 3. The hydraulic pump active noise control system according to claim 1 or 2, characterized in that: the control source (3) is close to the top and surrounding of the hydraulic pump (7). 4. The hydraulic pump active noise control system according to claim 1 or 2, characterized in that the control source (3) is a loudspeaker. 5. The hydraulic pump active noise control system according to claim 1, characterized in that the microphone (4) is an electret microphone.

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