CN101972994B - Soft abrasive grain flow generation and circulation system - Google Patents

Abstract

The invention relates to a soft abrasive grain flow generation and circulation system comprising a soft abrasive grain flow generation device and a soft abrasive grain flow circulation storage device, wherein the soft abrasive grain flow generation device comprises abrasive grain hydraulic control equipment and transfer fluid generation equipment; the liquid carrier generation equipment comprises a high-speed jet pump and a liquid carrier storage tank; the high-speed jet pump is connected with the transfer fluid storage tank through a pipeline; the abrasive grain hydraulic control equipment comprises a hydraulic transmission shaft and an abrasive grain storage tank; the output port of the high-speed jet pump is connected with the output port of the abrasive grain storage tank to form the outlet of the soft abrasive grain flow generation device; the soft abrasive grain flow circulation storage device comprises a constraint module and an abrasive grain flow storage tank; the inlet of the constraint module is connected with the outlet of the soft abrasive grain flow generation device; a piezoelectric thin film sensor is arranged on the pipeline at the inlet of the constraint module; and the piezoelectric thin film sensor is connected with an abrasive grain hydraulic control module. The system effectively prevents the pump body from damaging and realizes the accurate control of the viscosity and the circulation processing of a soft abrasive grain flow.

Description

Soft abrasive flow generation and circulation system

technical field

The invention aims at the problems of abrasive flow generation equipment loss due to the grinding action of solid particles in the soft abrasive flow precision finishing technology, and the control, output, and recycling of soft abrasive flow during processing. , Design a soft abrasive flow generation and circulation system.

Background technique

With the advancement of modern science and technology, the technological requirements for precision mechanical parts in aviation, electronics, computer and other industries are constantly increasing, and the trend of miniaturization of spare parts is also increasing, and the precision of workpieces is also continuously improving. Traditional machining methods with tools can no longer meet the needs of the manufacturing industry. In order to break through the technical bottleneck of traditional precision finishing, domestic and foreign experts have proposed fluid processing methods. Due to the "pervasive" flow characteristics of the fluid, the fluid can form a "seamless" contact with the processing surface, so the fluid processing technology has incomparable advantages in some specific processing occasions. Using the micro-force and micro-cutting effect of soft abrasive grain flow, tool-free precision machining of structured surfaces is realized.

In the processing process, the generation, output, circulation and recovery of the soft abrasive flow, as well as the design and installation of the restraint module are all important links. For the convenience of description, the implementation background and necessity of the soft abrasive flow generation and circulation system involved in the present invention are discussed here in conjunction with the solid-liquid two-phase abrasive flow processing technology.

The essence of soft abrasive flow processing is to use organic polymer materials as the carrier to suspend the abrasive particles with cutting effect to form a weakly viscous or non-viscous abrasive flow. The machined surface moves to produce cutting action for finishing. Among them, the soft abrasive flow is composed of carrier, additives and abrasive grains, and is a "flexible" tool for finishing. This technology effectively makes up for the disadvantages of traditional finishing processing methods for fine-scale structured surface processing, and can also process the surface processing of other complex workpieces.

Contents of the invention

In order to overcome the deficiencies of the existing soft abrasive flow generating device, which is easy to cause damage to the pump body, has poor viscosity control accuracy, and cannot realize cycle processing, the present invention provides a device that can effectively prevent damage to the pump body and realize the viscosity adjustment of the soft abrasive flow. Accurately control and realize the soft abrasive flow generation and circulation system of cyclic processing.

The technical solution adopted by the present invention to solve its technical problems is:

A soft abrasive flow generating and circulation system, comprising a soft abrasive flow generating device and a soft abrasive flow circulation storage device, the soft abrasive flow generating device includes abrasive hydraulic control equipment and carrier fluid generating equipment The carrier fluid generating equipment is composed of a high-speed jet pump and a carrier fluid storage tank, and the high-speed jet pump and the carrier fluid storage tank are connected by pipelines; the abrasive particle hydraulic control device is composed of a hydraulic transmission shaft and an abrasive particle storage tank Composition, the end of the hydraulic transmission shaft is connected with the piston, and the piston is movably sealed and installed in the abrasive storage box, the abrasive storage box on one side of the piston is a hydraulic oil chamber, and the abrasive storage box on the other side of the piston The grain storage box is an abrasive grain chamber, and the hydraulic transmission shaft is linked with the output shaft of the motor; the output port of the high-speed jet pump is connected with the output port of the abrasive grain storage tank to form the outlet of the soft abrasive grain flow generating device; The soft abrasive flow circulation storage device includes a restraint module and an abrasive flow storage box, the restraint module has a built-in workpiece, the inlet of the restraint module is connected with the outlet of the soft abrasive flow generating device, and the restraint module The outlet of the abrasive particle flow storage box is connected with the inlet of the abrasive particle flow storage box, the middle part of the abrasive particle flow storage box is provided with a filter screen, the abrasive particle flow storage box on one side of the filter screen is provided with an inlet and a first outlet, and the other The abrasive flow storage tank on one side is provided with a second outlet, the second outlet is connected to the input port of the high-speed jet pump, and the first outlet is connected to the carrier fluid storage tank;

The piezoelectric film sensor used to detect the pressure generated when the abrasive particle flow in the flow channel impacts the sensor is installed on the pipeline at the entrance of the constraint module. The piezoelectric film sensor is used to set the pressure threshold and the pressure and motor. The linear relationship of output power, when the pressure value detected by the sensor exceeds the pressure threshold, the motor output power is reduced, and when the pressure value detected by the sensor is lower than the pressure threshold, the wear particle hydraulic control module increases the motor output power.

Further, the piezoelectric film sensor uses polyvinylidene fluoride piezoelectric film as its sensitive element.

Still further, the output end of the piezoelectric film sensor is connected to a filter circuit, and the filter circuit includes an analog filter and a digital filter, the analog filter adopts a second-order Butterworth filter, and the digital filter adopts a singular value decomposition bandpass filter.

Furthermore, the filter circuit is connected to a limiter conditioning circuit for proportionally limiting the amplitude of the filtered signal within a range acceptable to the embedded digital signal processor.

The limiting and conditioning circuit is connected to an analog-to-digital conversion and conditioning circuit for converting the limited signal into a digital signal that can be recognized by the embedded digital signal processor.

The abrasive particle hydraulic control device and the carrier fluid generating device are placed in parallel.

The technical idea of the present invention is: the present invention mainly proposes how to generate the soft abrasive flow and how to recycle the workpiece after processing. Since the soft abrasive flow needs to have high speed and high pressure when it enters the restraint module to realize the turbulent flow form, it is necessary to use a water pump to inject the soft abrasive flow in the storage tank into the restraint module. Most of the water pumps with high-speed and high-pressure output cannot spray liquid with impurities (such as abrasive flow), which puts forward certain requirements for the generation of soft abrasive flow; at the same time, in order to meet the working conditions of the pump , It is bound to need to store the abrasive particles and the carrier fluid separately, so it also causes difficulties for the recycling of the soft abrasive flow.

Therefore, the present invention uses a high-speed jet pump and abrasive hydraulic control equipment to generate the carrier fluid and solid particles in the abrasive flow respectively, and mix them before entering the restraint module, which can effectively avoid abrasive particles with grinding ability The flow causes damage to the water pump; the feedback control system is formed by the embedded digital signal processor control chip, which can control the solid phase volume fraction of the abrasive flow at any time, so as to realize the adjustment of the viscosity of the abrasive flow, and finally achieve the best processing Efficiency; In addition, the separation of abrasive particles and carrier fluid in the abrasive flow storage tank solves the problem of separate feeding and collection of abrasive particles and carrier fluid during abrasive flow circulation processing.

The silicon carbide particles and fluid are stored in the abrasive particle flow storage tank, the storage tank includes an inlet and two outlets, and the two outlets serve as the inlets of the high-speed jet pump and the abrasive particle hydraulic device respectively. One of the outlets of the storage tank (at the inlet of the high-speed jet pump) is equipped with a filter screen, the purpose of which is to prevent the solid particles deposited at the bottom of the storage tank from being brought into the pump when the jet pump is working. When the system is working, the fluid in the abrasive particle flow storage tank is ejected at a high speed through the high-speed jet pump, and the abrasive particle hydraulic device ejects the abrasive particles in the abrasive particle storage tank through hydraulic work, and the fluid and abrasive particles enter the restraint module Before mixing. By controlling the power of the hydraulic device, the injection amount of abrasive particles can be controlled, so as to achieve the purpose of controlling the volume fraction of the solid phase of the soft abrasive flow. After the abrasive particle flow enters the restraint module, the workpiece is subjected to micro-force and micro-amount grinding. The processed abrasive flow enters the abrasive flow storage tank from the outlet of the restraint module. There is no stirring device installed in the storage tank, and the abrasive particles flow in the fluid. The medium naturally settles to the bottom of the box, waiting for the next cycle of operation. The structure diagram of this system is shown in Figure 1.

The abrasive particle hydraulic control device in the present invention is conceived as follows: the piezoelectric film sensor is installed at the entrance of the restraint module, and when the abrasive grain flow enters the restraint module, a pressure effect will be generated on the piezoelectric film sensor, and the piezoelectric film sensor will generate a piezoelectric signal, After the signal is digitally filtered (singular value decomposition band-pass filter method), amplitude limiting conditioning (because the signal entering the embedded digital signal processor has an upper limit of amplitude), analog-to-digital conversion, etc., it enters the embedded digital signal processor , after the embedded digital signal processor is processed, the initial pressure signal is converted into a control signal for controlling the power of the hydraulic motor, and the power of the hydraulic motor is adjusted to adjust the output of solid abrasive particles, and finally realize the adjustment of abrasive flow solids The purpose of particle volume fraction. The schematic diagram of the control system is shown in Figure 4.

The beneficial effects of the present invention are:

(1) The carrier fluid and abrasive particles are independently generated, which can effectively prevent solid particles from entering the high-speed jet pump and causing damage to the pump body;

(2) Using the embedded digital signal processor feedback control system to control the abrasive hydraulic device, the volume fraction of solid particles in the soft abrasive flow can be configured according to the needs, so as to realize the control of the viscosity of the soft abrasive flow. To achieve the best processing effect;

(3) Through the design method of separating the carrier fluid and abrasive particles in the abrasive flow storage tank, the soft abrasive flow cycle processing can be completed, which plays the role of energy saving and environmental protection.

Description of drawings

Fig. 1 is a schematic diagram of the overall system structure of the present invention.

Fig. 2 is a schematic diagram of the abrasive flow storage tank of the present invention.

Fig. 3 is a schematic diagram of the abrasive particle flow generating device of the present invention.

Fig. 4 is a control schematic diagram of the abrasive particle hydraulic control device of the present invention.

Fig. 5 is a control flow chart of the abrasive particle hydraulic control device of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1, Fig. 2, Fig. 3, Fig. 4, a soft abrasive flow generation circulation system is characterized in that it includes a soft abrasive flow circulation storage device 1 and a soft abrasive flow generation device 3; The soft abrasive flow circulation storage device 1 is composed of a soft abrasive flow storage tank 11 and a connecting pipeline 2; the soft abrasive flow generating device 3 is composed of a carrier fluid generating device 31 and an abrasive hydraulic control device 32; The soft abrasive flow storage device 1 and the generating device 3 are connected by pipelines 14 and 15 .

The soft abrasive flow generating device 3 includes carrier fluid generating equipment 31 and abrasive hydraulic control equipment 32; the carrier fluid generating equipment 31 is composed of a high-speed jet pump 314 and a carrier fluid storage tank, and the high-speed jet pump 314 is connected to a carrier fluid storage tank. The fluid storage tanks are connected by a pipeline 15; the abrasive particle hydraulic control device 32 is composed of an abrasive particle storage tank 321, a hydraulic transmission shaft 322 and a motor 323; the abrasive particle hydraulic control device 32 and the carrier fluid generating device 31 are parallel Placement; the output port 313 of the carrier fluid generating device 31 is connected to the output port 324 of the abrasive grain hydraulic control equipment, and the carrier fluid 311 is ejected to the abrasive grain outlet by the high-speed jet pump 314, so that the carrier fluid 311 and the abrasive grain 325 are mixed to form a certain concentration of soft abrasive particles flow 312 .

The abrasive particle hydraulic control device 32, the abrasive particle hydraulic control device 32 controls the hydraulic transmission shaft 322 through the motor 323, presses the solid abrasive particles out of the soft abrasive flow storage tank 11, and mixes them with the carrier fluid 311 to form A certain concentration of soft abrasive flow 312 .

The end of the hydraulic transmission shaft 322 is connected to the piston, and the piston is movably sealed and installed in the abrasive grain storage box 11. The abrasive grain storage tank 11 on one side of the piston is a hydraulic oil chamber, and the abrasive grain storage tank 11 on the other side of the piston is a hydraulic oil chamber. The abrasive grain storage box 11 is an abrasive grain chamber,

The abrasive particle hydraulic motor control system 32 , the abrasive particle hydraulic motor control system 32 uses an embedded digital signal processor 326 for feedback control, and the feedback signal comes from a piezoelectric film sensor 328 at the entrance of the constraint module 4 .

The piezoelectric film sensor 328, the piezoelectric film sensor 328 uses a polyvinylidene fluoride piezoelectric film as its sensitive element, and the polyvinylidene fluoride piezoelectric film is a unique polymer sensing material that can The corresponding voltage signal is output to the change of pressure; the input signal collected by the piezoelectric film sensor comes from the pressure 327 generated when the abrasive particle flow 312 in the flow channel impacts the sensor 328; the output signal of the piezoelectric film sensor 328 passes through Filtering, clipping, analog-to-digital conversion, etc. are adjusted and entered into the embedded digital signal processor 326 for feedback control calculation.

The filter conditioning process, the filter conditioning process includes analog filtering and digital filtering, the analog filtering uses a second-order Butterworth filter, and its main function is to filter glitches and clutter in the sampling signal; The digital filtering adopts the singular value decomposition band-pass filtering method, and its main function is to process the sampled error signal in the digital signal to obtain the best sampling value involved in the calculation; the main function of the limiting conditioning process is to convert the The equal ratio of the filtered signal amplitude is limited within the acceptable range of the embedded digital signal processor 326, so as to prevent damage to the embedded digital signal processor 326; The signal processor 326 has its own A/D conversion unit to convert the limited signal into a digital signal that can be recognized by the embedded digital signal processor.

In the embedded digital signal processor feedback control system, the embedded digital signal processor 326 feedback control system adopts negative feedback proportional control. When the pressure value detected by the sensor is too large, it means that the viscosity of the abrasive grain flow is too high, The content of abrasive grains is large, and the output power of hydraulic motor 323 can be controlled by online adjustment, thereby reducing the output of abrasive grains and achieving the purpose of reducing the viscosity of abrasive grain flow; the same can be obtained when the viscosity of abrasive grain flow is too low.

The soft abrasive flow circulation storage device 1 is composed of a restriction module 4 , a pipeline 5 and a soft abrasive flow storage tank 11 . The restraint module 4 has a built-in workpiece, the inlet of the restraint module 4 is connected with the outlet of the soft abrasive flow generating device 3 , and the outlet of the restraint module 4 is connected with the soft abrasive flow storage tank 11 .

The soft abrasive flow storage box 11, the abrasive flow storage box 11 is composed of an inlet 2 and two outlets 14, 15, the inlet 2 is connected to the outlet of the restriction module 4 through pipelines, so that the complete The processed soft abrasive flow 12 enters the abrasive flow storage tank 11; the two outlets 14, 15 serve as the ports of the abrasive hydraulic control device 32 and the carrier fluid generating device 31 in the soft abrasive flow generating device 3 respectively. Entrance.

The abrasive flow storage tank 11 has a built-in filter screen 16, and the filter screen 16 separates an outlet (inlet of the high-speed jet pump) 15 in the abrasive flow storage tank from the abrasive particles 13 to ensure that the abrasive particles enter the high-speed jet pump 314 The purity of the fluid. The specific structure is: the middle part of the abrasive flow storage box is provided with a filter screen 16, the abrasive flow storage box on one side of the filter screen 26 is provided with an inlet and a first outlet, and the abrasive flow storage box on the other side A second outlet is provided, the second outlet is connected to the input port of the high-speed jet pump, and the first outlet is connected to the carrier fluid storage tank

The invention can be used to process the structured surface of the fine-sized mold by adopting the soft abrasive grain flow, and provides recyclable solid-liquid two-phase soft abrasive grain flow. In the present invention, the embedded digital signal processor control chip adopts the TMS320LF2407 DSP control chip, which has strong digital signal processing capability and can quickly process the sampled data. The piezoelectric thin film sensor in the present invention adopts a polyvinylidene fluoride (PVDF) piezoelectric thin film sensor, which has higher sensitivity to micro pressure signals.

The working process of the present invention is: silicon carbide particles 13 and fluid 311 are stored in the abrasive particle flow storage tank 11, the storage tank 11 includes an inlet 1 and two outlets 14,15, and the two outlets 14,15 are respectively used as high-speed jets Inlet for pump 314 and abrasive hydraulics 32 . One of the outlets (at the inlet of the high-speed jet pump) 15 of the storage tank 11 is equipped with a filter screen, the purpose of which is to prevent the solid particles 13 deposited at the bottom of the storage tank 11 from being brought into the pump when the jet pump 314 is working. When the system is working, the fluid in the abrasive flow storage tank 11 is ejected at a relatively high speed through the high-speed jet pump 314, and the abrasive particle hydraulic device 32 ejects the abrasive particles 13 in the abrasive particle storage tank 11 through hydraulic work, and the fluid 311 and The abrasive particles 13 are mixed before entering the confinement module 4 . The piezoelectric film sensor 328 is installed at the entrance of the constraint module 4. When the mixed abrasive grain flow 312 enters the constraint module 4, a pressure effect will be generated on the piezoelectric film sensor 328. The piezoelectric film sensor generates a piezoelectric signal 327, and the signal Perform digital filtering (singular value filtering), limiting conditioning (because the signal entering the embedded digital signal processor has an upper limit of amplitude), analog-to-digital conversion, etc., and then enter the embedded digital signal processor 326, and the embedded digital signal processing After calculation and processing, the device 326 converts the initial pressure signal 327 into a control signal for controlling the power of the hydraulic motor, and adjusts the power of the hydraulic motor 323, thereby adjusting the output of solid abrasive particles, and finally adjusting the volume fraction of solid particles in the abrasive flow. the goal of. After the abrasive particle flow 312 enters the constraint module 4, the workpiece is subjected to micro-force and micro-amount grinding, and the processed abrasive particle flow 12 enters the abrasive particle flow storage box 11 through the constraint module outlet pipeline 5, and the storage box 11 is not installed. Stirring device, the abrasive particles 13 naturally settle to the bottom of the box in the fluid, waiting for the next cycle of operation.

The content described in the embodiments of this specification is only a partial list of the realized forms of the inventive concept. The protection scope of the present invention should not be limited to the specific forms stated in the examples. The protection scope of the present invention is limited to those skilled in the art according to the present invention Equivalent technical means that can be imagined by the technical concept.

Claims (6)

1. a soft abrasive stream takes place and the circulatory system, it is characterized in that: comprise soft abrasive flow generating apparatus and soft abrasive stream circulation storage device, said soft abrasive flow generating apparatus comprises abrasive particle hydraulic-pressure control apparatus and carrying object generation equipment; Said carrying object generation equipment is made up of high-speed jet pump and carrying object storage bin, is linked to each other by pipeline between high-speed jet pump and the carrying object storage bin; Said abrasive particle hydraulic-pressure control apparatus is made up of hydraulic drive axle and abrasive particle storage bin; The end of said hydraulic drive axle is connected with piston; Said piston seals movably and is installed in the said abrasive particle storage bin; The abrasive particle storage bin of piston one side is a hydraulic fluid chamber, and the abrasive particle storage bin of piston opposite side is the abrasive particle chamber, the output shaft interlock of said hydraulic drive axle and motor; The delivery outlet of said high-speed jet pump links to each other with the delivery outlet of abrasive particle storage bin and forms the outlet of soft abrasive flow generating apparatus; Said soft abrasive stream circulation storage device comprises constraints module and abrasive Flow storage bin; The built-in workpiece to be machined of said constraints module; The inlet of constraints module links to each other with the outlet of said soft abrasive flow generating apparatus, and the outlet of said constraints module links to each other with the inlet of said abrasive Flow storage bin, and the middle part of said abrasive Flow storage bin is provided with screen pack; The abrasive Flow storage bin of one side of said screen pack is provided with the inlet and first outlet; The abrasive Flow storage bin of opposite side is provided with second outlet, and said second outlet links to each other with the input port of high-speed jet pump, and said first outlet links to each other with said carrying object storage bin;

On the pipeline of said constraints module import department, install in order to detect the piezoelectric film sensor of the pressure that is produced when abrasive Flow is impacted sensor in the runner; Said piezoelectric film sensor is connected with the abrasive particle hydraulic control module; Said abrasive particle hydraulic control module is in order to the linear relationship of setting pressure threshold value and pressure and motor power output; When the detected force value of sensor exceeds pressure threshold, reduce the motor power output, when the detected force value of sensor is lower than pressure threshold, increase the motor power output.

2. soft abrasive stream as claimed in claim 1 takes place and the circulatory system, it is characterized in that: said piezoelectric film sensor adopts poly meta fluoroethylene piezoelectric film as its sensing element.

3. according to claim 1 or claim 2 soft abrasive stream takes place and the circulatory system; It is characterized in that: the output of said piezoelectric film sensor connects filter circuit; Said filter circuit comprises analog filtering and digital filtering; Said analog filtering adopts the fertile thatch wave filter of second order Bart, and said digital filtering adopts the singular value decomposition bandpass filter.

4. soft abrasive as claimed in claim 3 stream takes place and the circulatory system, it is characterized in that: said filter circuit connect in order to will pass through filtered signal amplitude equal proportion be limited to embedded dsp the amplitude limit modulate circuit within the receptible scope.

5. soft abrasive as claimed in claim 4 stream takes place and the circulatory system, it is characterized in that: said amplitude limit modulate circuit connects in order to the signal after the amplitude limit is converted into the analog-to-digital conversion modulate circuit of the data signal that embedded dsp can discern.

6. according to claim 1 or claim 2 soft abrasive stream takes place and the circulatory system, it is characterized in that: the parallel placement of said abrasive particle hydraulic-pressure control apparatus and carrying object generation equipment.

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