Noise reduction method for concrete shock excitation forming platform

Abstract

The invention relates to a noise reduction method for a concrete shock excitation forming platform, and belongs to the field of vibration and noise. According to the noise reduction method of the concrete shock excitation forming platform, a hydraulic cylinder actuator is used for clamping a mold on a vibration platform, the hydraulic actuator is driven by a 2D hydraulic shock excitation valve and is connected with a three-position five-way servo sliding valve in parallel, and the tail end of a piston rod of the hydraulic actuator is connected with a composite shock absorber. According to vibration parameters measured by the vibration analyzer, the embedded system controls the hydraulic actuator to enable the composite shock absorber to achieve the work cycle of pressing-same-frequency and same-phase vibration-loosening, collision caused by separation of the platform and the mold is avoided, and the purpose of active vibration control is achieved. The vibration damper has the advantages of being simple and reasonable in structure and convenient to manufacture, install and use, is particularly suitable for vibration forming equipment of concrete members, such as a sleeper vibration forming process, can effectively overcome the defect that noise is large in heavy-load high-frequency excitation, improves the production environment, and protects physical and psychological health of staff.

Description

Technical Field

[0001] The invention relates to a noise reduction method for a concrete excitation forming platform, in particular to a shock absorption and noise reduction technology for special equipment for producing train sleepers, and belongs to the field of vibration and noise. Background Art

[0002] Since the early years of prefabricated cement floor slabs, the concrete excitation molding platform has been an essential production equipment. Although the degree of automation has been greatly improved, the noise in the production environment is too high, threatening the physical and mental health of workers. For example, the concrete excitation production line responsible for the vibration molding of the sleeper will produce noise up to 120 dB, which is particularly prominent. This is mainly because the current vibration is mostly mechanical vibration of the centrifugal force of the eccentric block. Although it has the advantages of large vibration force and large amplitude, the huge molding mold filled with concrete vibrates up and down on the platform. The excitation force is a sinusoidal change of time. When the absolute value of the upward acceleration is higher than the gravity acceleration and the downward acceleration value is greater than one g, the molding mold will be vibrated off the platform, that is, the impact frequency is much higher than the excitation frequency. The general mechanical vibration frequency is 40-50Hz, and the corresponding impact frequency is above 100Hz, which objectively increases the vibration frequency and enhances the vibration effect. However, the high-energy collision between the steel mold and the steel platform also has a very prominent noise hazard. In order to reduce noise, the mold must be reliably "tied" to the platform to avoid the above collision. 202421119580.1 The same is true for the excitation principle of a material compact and uniform vibration platform. If there is no fixture, the collision noise between the platform and the mold is inevitable. The current electro-hydraulic exciter is mainly composed of a hydraulic oil source, an electro-hydraulic servo valve, a hydraulic actuator, a rack and a computer control system. The high-frequency servo valve controls the hydraulic power source to enter and exit the two chambers of the hydraulic cylinder or hydraulic motor, and drives the piston to output the hydraulic pressure. Limited by the inherent characteristics of the servo valve, it is difficult to meet the requirements of high frequency and wide amplitude at the same time. Even so, when the actuator is high-frequency reversing, the acceleration will change suddenly, and its absolute value will instantly become hundreds to hundreds of times the exciting force, and then immediately drop to zero, and quickly maintain a stable exciting force. The reversal of the actuator may also cause the molding mold to detach from the platform. The most critical thing is that the sleeper production line can only adopt multi-platform joint vibration, especially mechanical vibration, because of the huge load and the large size of the high-power motor. It is difficult to accurately adjust the force output phase of each platform, making the collision noise more intense. Therefore, it is necessary to develop a noise reduction method for the concrete vibration forming platform, rather than a passive energy-consuming vibration reduction method such as ordinary shock absorbers or vibration isolation pads. Because for the rail sleeper vibration forming equipment, the rubber contact surface of the ordinary vibration isolation pad placed between the platform and the steel mold is very easy to wear, and the general shock absorbers or vibration isolation pads are energy-consuming, and the shock-absorbing clamp only clamps the mold on the platform, and the shock-absorbing clamp itself hardly absorbs the exciting force, but is a semi-active shock-absorbing measure.However, although active shock absorption or hybrid shock absorption with semi-active shock absorption is difficult to promote in building shock absorption because the control object is too large and the energy cost is too high, it is feasible to borrow vibration control methods from the field of building structure on the concrete vibration forming platform. The only difference is that building structure shock absorption is to eliminate the impact of low-frequency vibrations such as earthquakes or underground rail transit vibrations and wind vibrations on ground buildings, while the concrete vibration forming platform is more for better utilizing the exciting force transmitted by the vibration platform, transmitting it to the concrete mortar in the mold for tamping, and preventing the mold from being vibrated off the platform during vibration and causing collision and impact noise. Summary of the invention

[0003] The purpose of the present invention is to provide a noise reduction method for a concrete vibration forming platform, which can overcome the above technical problems. The scheme is as follows: The present invention discloses a noise reduction method for a concrete excitation forming platform, which uses a hydraulic cylinder actuator to clamp the mold on the vibration platform. The hydraulic actuator is driven by a 2D hydraulic excitation valve, and is connected in parallel with a three-position five-way servo slide valve. The end of the piston rod of the hydraulic actuator is connected to a composite shock absorber. The composite shock absorber can be controlled to tighten or loosen the mold with a large stroke by controlling the three-position five-way servo slide valve. The excitation force driven by the 2D hydraulic excitation valve further controls the appropriate elastic block preload to offset the influence of the unbalanced force between the excitation platform and the object to be vibrated, that is, the upward excitation force is greater than the dead weight of the object to be vibrated or the acceleration of the downward excitation force is greater than one g, so that the object to be vibrated loses weight, the pressure on the platform is zero, and it is separated, so as to avoid the collision between the platform and the object to be vibrated due to separation, and achieve the purpose of active noise reduction.

[0004] As a preferred method for reducing the noise of the concrete excitation forming platform, the hydraulic cylinder actuator is specifically a plurality of hydraulic cylinders with the same parameters, and is synchronously acted on by the same 2D hydraulic excitation valve through a synchronous hydraulic circuit. The mold can be clamped at multiple points to prevent the long mold from being deformed or worn due to long-term use and having poor contact with the vibration platform, so that the vibration platform can better transmit the excitation force.

[0005] Preferably, a noise reduction method for a concrete vibration forming platform is provided, wherein the hydraulic cylinder actuator is a small shock-absorbing cylinder, and the 2D hydraulic vibration valve is also connected in parallel with a main vibration cylinder via a synchronous hydraulic circuit, and the main vibration cylinder is placed below the vibration platform. The essence of this solution is to use the same high-pressure hydraulic oil on the electro-hydraulic vibration platform to drive each branch of the synchronous hydraulic circuit to vibrate at the same frequency and in the same phase, but the main vibration cylinder drives the platform to vibrate up and down, while the small shock-absorbing cylinder clamps the mold and vibrates at the same frequency to adjust the force of the composite shock absorber. This solution can directly eliminate the sensors related to the vibration meter, and the matching adjustment and control of the vibration parameters can be guaranteed by the liquid system alone, simplifying the control strategy to an open-loop active control measure.

[0006] As a preferred embodiment, a noise reduction method for a concrete excitation molding platform is provided, wherein a vibration analyzer is installed on the vibration platform, and the composite shock absorber is controlled by an embedded system to preload and tighten downwards - excite at the same frequency and phase - release and rise according to the real-time working parameters, i.e., open-loop active control. For any excitation method, according to the real-time working parameters measured by the vibration analyzer, the embedded system controls the composite shock absorber to preload and tighten downwards - excite at the same frequency and phase by a parallel three-position five-way servo slide valve - and finally the composite shock absorber is raised by a parallel three-position five-way servo slide valve to release the mold. The vibration analyzer inputs the measured vibration main frequency, amplitude, phase and other parameters into the embedded system, controls the 2D hydraulic excitation valve to excite at the same frequency and phase, and the composite shock absorber can generate a suitable additional force to prevent the mold from being vibrated off the platform. The so-called suitable additional force is the platform excitation force = mold gross weight + additional force. It should be noted that the platform excitation force and the additional force are both time-varying forces with the same frequency and phase, except that the hydraulic actuator drives the composite shock absorber to clamp the mold downward on the vibration platform.

[0007] Preferably, a noise reduction method for a concrete vibration forming platform is provided, wherein a plurality of composite shock absorbing fixtures are installed on the vibration platform to realize hybrid control. On the basis of the active control of the aforementioned scheme, a plurality of composite shock absorbing fixtures are installed on the vibration platform to realize hybrid control, which can appropriately reduce the energy consumption of the hydraulic actuator in active control without increasing the cost much. The use of composite shock absorbing fixtures is a semi-active control. When the composite shock absorbing fixtures are loaded, the stiffness and damping of the vibration platform and the mold are changed. This change is the internal force between the vibration platform and the mold, which does not require the input of external energy, thereby achieving energy saving.

[0008] Therefore, the present invention has the characteristics of reasonable structure, easy manufacturing, installation and use. The noise reduction method of the concrete vibration forming platform is particularly suitable for vibration forming equipment of concrete components, such as use in the vibration forming process of sleepers. It can effectively overcome the shortcomings of high noise in heavy-load vibration, improve the production environment, and protect the physical and mental health of employees. Some schemes can be used to transform the existing concrete vibration forming platform at a low cost, which can achieve considerable social value and embody the purpose of "people-oriented, quality first". BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a working principle diagram of the present invention; Figure 2 is a hydraulic principle diagram of embodiment 1 of the present invention (extended); Figure 3 is a hydraulic principle diagram of embodiment 1 of the present invention (retracted); Figure 4 is a schematic diagram of the working example 2 of the present invention; Figure 5is a hydraulic principle diagram of embodiment 3 of the present invention; Figure 6 It is a control principle diagram of embodiment 4 of the present invention.

[0010] In the figure: 1. 2D excitation valve; 1a. Valve core; 1b. Valve sleeve; 1c. Window; 2. Hydraulic actuator; 2a. Small shock-absorbing cylinder; 2b. Main exciting cylinder; 3. Three-position five-way servo slide valve; 4. Composite shock absorber; 5. Composite shock absorbing fixture; 6. Vibration platform; 7. Mould. DETAILED DESCRIPTION

[0011] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0012] Embodiment 1: According to Figures 1 to 3The scheme published is now explained in detail. A noise reduction method for a concrete excitation molding platform uses a plurality of hydraulic actuators 2 to clamp the mold 7 on the vibration platform 6. The hydraulic actuator is driven by a 2D hydraulic excitation valve 1, and a three-position five-way servo slide valve 3 is connected in parallel. The end of the piston rod of the hydraulic actuator 2 is connected to the composite shock absorber 4. The embedded system controls the three-position five-way servo slide valve to achieve the large stroke of the composite shock absorber to press or loosen the mold. The excitation force driven by the 2D hydraulic excitation valve 2 further controls the appropriate pre-tightening force of the composite shock absorber 4 to offset the influence of the unbalanced force between the vibration platform 6 and the mold 7, that is, the upward excitation force is greater than the gross weight of the mold 7 or the acceleration of the downward excitation force is greater than one g, and the mold 7 loses weight, the pressure on the vibration platform 6 is zero, causing separation, avoiding the collision between the vibration platform 6 and the mold 7 due to separation, and achieving the purpose of active noise reduction. The 2D excitation valve 1 used in the present invention is a new type of high-efficiency hydraulic software invented by Professor Ruan Jian of Zhejiang University of Technology. Driving the valve can realize high-frequency reversal of the liquid flow. When the valve core 1a rotates at high speed, the fixed valve sleeve 1b can periodically close the window 1c, and the high-pressure liquid flow switches the direction in the two oil chambers of the hydraulic actuator 2 at high frequency, realizing the excitation of the hydraulic actuator 2. The axial displacement of the driving valve core 1a can also change the flow rate and flow rate from the axial switch window 1c. In short, the 2D excitation valve 1 has adjustable frequency and amplitude. The hydraulic transmission has a high energy density and can achieve high-thrust high-frequency vibration. For the sleeper production line of concrete component molding, it is not actually necessary to have a large amplitude. The key indicator is high thrust and high frequency. That is, when the upward excitation force is greater than the gross weight of the mold 7 or the acceleration of the downward excitation force is greater than one g, and the mold 7 loses weight, the pressure applied by the mold 7 to the vibration platform 6 is zero, causing separation. In order to avoid the vibration platform 6 and the mold 7 from detaching and causing a head-on collision or chase collision, the purpose of active noise reduction is achieved. The three-position five-way servo slide valve 3 drives the composite shock absorber 4 at the end of the piston rod of the hydraulic actuator 2 to move downward to press the mold 7 and maintain the pressure, and controls the valve core 1a of the 2D hydraulic excitation valve 2 to rotate at high speed, so that the high-pressure oil repeatedly enters and exits the hydraulic actuator 2, and vibrates at the same frequency and phase as the exciting force on the vibration platform 6. The composite shock absorber 4 generates a suitable additional force, and the so-called suitable additional force is the vibration platform exciting force = mold gross weight + additional force. It should be noted that the vibration platform exciting force and the additional force are both time-varying forces with the same frequency and phase, but the hydraulic actuator drives the composite shock absorber to clamp the mold downward on the vibration platform 6. After the vibration tamping time is up, the excitation stops, and the three-position five-way servo slide valve 3 drives the composite shock absorber 4 at the end of the piston rod of the hydraulic actuator 2 to move upward with a large displacement to release the mold 7, allowing the mold 7 to move forward and leave the vibration platform 6 to complete a working cycle.

[0013] Embodiment 2: According to Figures 1 to 4The scheme published is now explained in detail. Compared with Example 1, several composite shock-absorbing clamps 5 are also installed on the vibration platform 6 in this example to achieve hybrid control. On the basis of the active control of the aforementioned scheme, several composite shock-absorbing clamps 5 are also installed on the vibration platform 6 to achieve hybrid control, which can reduce the diameter of the hydraulic actuator 2 without increasing the cost, facilitate the layout, and also reduce the energy consumption of the hydraulic actuator 2 in active control. The use of the composite shock-absorbing clamp 5 is a semi-active control. The composite shock-absorbing clamp 5 is loaded, so that the stiffness and damping of the vibration platform 6 and the mold 7 as a whole change. And this change is the internal force between the vibration platform 6 and the mold 7, without the input of external energy, so as to achieve the effect of energy saving. And multi-point clamping can better ensure the close fit between the vibration platform 6 and the mold 7, prevent the mold 7 from being vibrated away and then colliding, and generate noise. In engineering practice, the hybrid control of active vibration control and semi-active vibration control is relatively rare, especially in the application scenario of concrete excitation molding that itself uses vibration. The purpose is to reduce passive energy consumption as much as possible, so that the exciting force is fully absorbed by the mortar in the mold 7 to make it uniform, and squeeze out the air to ensure the quality of the concrete prefabricated part. Especially in the sleeper exciting forming process with a very long mold 7, the effect of the multi-point arrangement of the composite shock absorbing fixture 5 is very significant.

[0014] Embodiment 3: Figure 1 and Figure 5 The scheme published is a noise reduction method for a concrete excitation forming platform, wherein the plurality of hydraulic cylinder actuators 2 are small shock-absorbing cylinders 2a, and the 2D hydraulic excitation valve is also connected in parallel with a main excitation cylinder 2b through a synchronous hydraulic circuit, and the main excitation cylinder 2b is placed below the vibration platform 6. The essence of this scheme is to use the same high-pressure hydraulic oil on the electro-hydraulic excitation platform to drive the branches of the synchronous hydraulic circuit to vibrate at the same frequency and phase, but the main excitation cylinder 2b drives the platform to vibrate up and down, while the small shock-absorbing cylinder 2a clamps the mold 7 and vibrates at the same frequency to adjust the force of the composite shock absorber. Note that the small shock-absorbing cylinder 2a actually installed is installed downward. This scheme can directly cancel the embedded system of the relevant sensors or control strategies of the vibration meter, and only the liquid system can ensure the matching adjustment and control of vibration parameters, such as amplitude, excitation force, frequency and phase difference, simplify the control strategy to an open-loop active control measure, reduce the control cost, and change the vibration mode of the vibration platform is also a way to reduce noise. The relevant invention application has been submitted in the early stage.

[0015] Embodiment 4: Figure 1 and Figure 6, a noise reduction method for a concrete excitation molding platform, a vibration analyzer is installed on the vibration platform 6, and the embedded system controls the downward pre-tightening-same frequency and same phase excitation-release and rising of the composite shock absorber 4 according to the real-time working parameters, that is, open-loop active control. For any excitation method, according to the real-time working parameters measured by the vibration analyzer, the embedded system controls the parallel three-position five-way servo slide valve 3 to first drive the composite shock absorber 4 to press down and pre-tighten-same frequency and same phase excitation-finally, the parallel three-position five-way servo slide valve 3 is used to make the composite shock absorber 4 rise and release the mold 7. The vibration analyzer inputs the measured vibration main frequency and amplitude, phase and other parameters into the embedded system, controls the 2D hydraulic excitation valve to excite at the same frequency and same phase, and the composite shock absorber 4 can generate a suitable additional force to prevent the mold 7 from being vibrated away from the platform 6. The so-called suitable additional force, that is, the platform excitation force = mold gross weight + additional force. It should be noted that the platform excitation force and the additional force are both time-varying forces of the same frequency and phase, except that the hydraulic actuator 2 drives the composite shock absorber 4 to clamp the mold downward on the vibration platform 6. The vibration analyzer can use the Japanese RION vibration analyzer, and the data can be directly imported into the embedded system, which reduces the computing pressure of the embedded system itself and focuses on the use of input signals and the output of control signals. The concrete excitation molding platform of this embodiment realizes intelligent control, improves automation, and achieves the beneficial effects of high efficiency, energy saving and environmental protection.

[0016] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that simple variations such as changing the number of composite shock absorbers 4 or the specific computer platform of the controller can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A method for reducing noise of a concrete vibration forming platform, using a hydraulic actuator (2) to clamp a mold (7) on a vibration platform (6), characterized in that The hydraulic actuator (2) is driven by a 2D hydraulic excitation valve (1) and is connected in parallel with a three-position five-way servo slide valve (3). The end of the piston rod of the hydraulic actuator is connected to a composite shock absorber (4).

2. The noise reduction method of the concrete vibration forming platform according to claim 1, characterized in that The hydraulic actuator (2) is specifically a plurality of hydraulic cylinders with the same parameters, and is synchronously acted upon by the same 2D hydraulic excitation valve (1) via a synchronous hydraulic circuit.

3. The noise reduction method of the concrete vibration forming platform according to claim 1 or 2, characterized in that The hydraulic actuator (2) is a small shock-absorbing cylinder (2a), and the 2D hydraulic excitation valve (1) is also connected in parallel with a main excitation cylinder (2b) via a synchronous hydraulic circuit, and the main excitation cylinder is placed below the vibration platform (6).

4. The noise reduction method of the concrete vibration forming platform according to claim 1 or 2, characterized in that A vibration analyzer is installed on the vibration platform (6), and the composite shock absorber (4) is controlled by an embedded system according to real-time working parameters to perform downward pre-tightening, same-frequency and same-phase excitation, and loosening and rising, i.e., open-loop active control.

5. The noise reduction method of the concrete vibration forming platform as claimed in claim 4, characterized in that A plurality of composite shock-absorbing fixtures (5) are also installed on the vibration platform (6) to achieve hybrid control.

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