CN103231310B - Cryogenic cooling and nano particle jet flow minimal quantity lubrication coupling grinding medium supply system - Google Patents

Abstract

The invention relates to a grinding medium supply system coupled with low-temperature cooling and nano-particle jet micro-lubrication. It includes at least one combination unit of micro-lubrication and low-temperature cooling nozzle, which is arranged on the side of the grinding wheel cover of the grinding wheel and cooperates with the workpiece on the workbench; The atomizing micro nozzle is connected to the nanofluid pipeline and the compressed air pipeline, and the low-temperature cooling nozzle is connected to the low-temperature coolant pipeline; the nanofluid pipeline, compressed air pipeline and low-temperature coolant pipeline of each unit pass through the control valve It is connected with the nanofluid supply system, the low temperature medium supply system and the compressed air supply system, and the nanofluid supply system, the low temperature medium supply system and the compressed air supply system are connected with the control device. It effectively solves grinding burns, improves the surface quality of workpieces, and realizes low-carbon green and clean production with high efficiency, low consumption, environmental friendliness and resource saving.

Description

Grinding medium supply system coupled with cryogenic cooling and nanoparticle jet microlubrication

technical field

The invention relates to a grinding medium supply system in the field of grinding processing, in particular to a grinding medium supply system coupled with low-temperature cooling and nano particle jet microlubrication.

Background technique

Due to the high grinding force and specific grinding energy, the grinding process generates a lot of heat in the grinding area. Since the metal layer to be cut is relatively thin, about 60%-90% of the heat is transferred to the workpiece, and only less than 10% of the heat is taken away by the grinding debris. The heat introduced into the workpiece is often too late to be transmitted to the depth of the workpiece during the grinding process, and it gathers in the surface layer to form a local high temperature. The surface temperature of the workpiece can often reach above 1000 °C. The layer forms a huge temperature gradient (up to 600-1000°C/mm). Therefore, the thermal effect of grinding has a great influence on the surface quality and performance of the workpiece. Especially when the temperature exceeds a certain critical value on the interface, it will cause surface thermal damage (surface oxidation, burns, residual stress and cracks), which will result in reduced wear resistance of parts and increased sensitivity to stress corrosion , The anti-fatigue performance becomes poor, thereby reducing the service life and working reliability of the parts. In addition, the cumulative temperature rise of the workpiece during the grinding cycle often leads to errors in the dimensional accuracy and shape accuracy of the workpiece. On the other hand, the grinding heat in the grinding zone not only affects the workpiece, but also affects the service life of the grinding wheel. Therefore, controlling the temperature in the grinding area is one of the powerful measures to improve the grinding ability and the surface quality of the workpiece. In actual production, the temperature of the grinding zone is often reduced by selecting appropriate grinding wheels, optimizing process parameters, increasing supply (cooling) fluid pressure and flow rate, but these methods can only reduce grinding damage to a certain extent. However, because the grinding fluid used in grinding contains oil and a large amount of harmful chemical components, it will cause serious environmental pollution. Therefore, a low-toxicity, low-pollution low-temperature grinding system is developed, so that it has good low-temperature fluidity, strong cooling performance and good lubrication performance, and can be poured continuously in the grinding area under low temperature conditions to form In the local low-temperature area, less or no grinding fluid is used, and green manufacturing in grinding processing is realized.

In order to reduce the temperature in the grinding area, many methods have been adopted, such as low-temperature liquid nitrogen cooling processing method and low-temperature CO2 spray processing method. These processing methods have been proved to have good processing effects. Low-temperature cooling grinding sprays low-temperature cooling medium to the grinding area, and takes away the heat generated in the grinding area through heat exchange, so as to achieve the purpose of cooling.

At present, the grinding process uses a large amount of lubricants, also known as cast grinding, which is very harmful to the environment and workers' health. Due to the requirements of environmental protection, the waste liquid of lubricant must be treated and discharged after reaching the standard. Waste liquid treatment costs a lot, as high as 54% of the cost of lubricant, so people have to re-evaluate lubricant. Germany has conducted a survey on automobile manufacturers, and the result is that the tool cost only accounts for 2%-4% of the processing cost; but the cost related to lubricants accounts for 7%-17% of the cost, which is 3% of the tool cost. -5 times. Energy consumption in machining, the power required for the spindle to run only accounts for 20%, and the energy consumption related to cooling and lubrication accounts for 53%. This shows that due to the requirements of "environmental protection and low carbon", the cheap advantage of lubricants no longer exists, and has become an obstacle affecting the development of production.

In order to protect the environment and reduce costs, dry grinding, which consciously completely stops the use of lubricants, came into being. Due to the abandonment of the use of lubricants, the advantages of dry grinding in terms of environmental protection are self-evident. However, since the energy consumed by grinding per unit volume of material is much greater than that of milling, turning, drilling and other processing methods, such a high energy density is generated at the grinding wheel/workpiece interface, and only less than 10% of the heat is ground The heat transferred to the workpiece will gather in the surface layer to form a local high temperature. Therefore, no lubricant is used in the grinding process, which not only deteriorates the surface quality of the processed workpiece, but also greatly reduces the service life of the grinding wheel, or even scraps it. .

The minimum quantity lubrication technology between pouring wet grinding and dry grinding is to use the minimum amount of lubricant under the premise of ensuring lubricating performance and cooling effect. Minimal quantity lubrication is to mix a small amount of lubricant into the high-pressure gas, which is mixed and atomized by high-pressure airflow (4.0-10bar) and then enters the high-temperature grinding area. The amount of grinding media used in the traditional pouring liquid supply method is 60L/h per unit width of the grinding wheel, while the consumption of grinding media for minimal quantity lubrication is only 30-100ml/h per unit width of the grinding wheel. The high-pressure airflow plays the role of cooling and chip removal, and the lubricant adheres to the processing surface of the workpiece to form a protective film and play the role of lubrication. This technology combines the advantages of pouring grinding and dry grinding, and the lubrication effect is almost the same as that of traditional pouring grinding. Lubricants generally use vegetable oil as the alkyl ester of the base oil, which has excellent biodegradability, lubricating performance, high viscosity index, low volatility, renewable, short production cycle, and less environmental diffusion. The amount of lubricant used It is only a few thousandths or even a few ten thousandths of the traditional processing method, which greatly improves the working environment and is an efficient, low-carbon and environmentally friendly processing technology. However, studies have shown that the cooling effect of high-pressure airflow is very limited, which cannot meet the needs of enhanced heat transfer in high grinding areas. The processing quality of workpieces and the life of grinding wheels are significantly lower than those of traditional pouring grinding, indicating that the minimal quantity lubrication technology needs further improvement. with perfection.

According to the enhanced heat transfer theory, the heat transfer capacity of solid is much greater than that of liquid and gas. At room temperature, the thermal conductivity of solid materials is several orders of magnitude greater than that of fluid materials. The thermal conductivity of a liquid suspended with metal, non-metal or polymer solid particles is dozens or even hundreds of times greater than that of a pure liquid. Adding solid particles to the MQL medium can significantly increase the thermal conductivity of the fluid medium, improve the ability of convective heat transfer, and greatly compensate for the lack of cooling capacity of MQL. In addition, nanoparticles (refers to ultra-fine solid particles with at least one dimension in the nanoscale range (1-100nm) in three-dimensional space) also have special anti-wear and friction reduction and high load-bearing capacity in terms of lubrication and tribology. academic characteristics.

The preparation method of the minimum quantity lubrication lubricant is to add alkyl sulfonate surfactant and dimethyl sulfate dispersant to the mixture of nanoparticles and degradable grinding media, and then use 16,000-20,000 times/minute high Frequency vibration to obtain a stable suspension.

Nanoparticles are graphite particles or aluminum oxide, carbon nanotubes, and metals with a particle size of less than 100nm. The volume content of nanoparticles in the lubricant is 1%-30vol%, and the grinding medium is degradable lubricating oil or vegetable oil.

The inventor has carried out in-depth theoretical analysis and experimental verification on the minimum quantity lubrication grinding supply system. The research results have applied for related patents. No.: 201210153801.2) discloses a nano-particle jet micro-quantity lubrication grinding lubricant supply system, which adds nano-scale solid particles into degradable grinding fluid to make a micro-quantity lubrication grinding lubricant, which is supplied by the micro-quantity supply device The lubricant becomes pulse droplets with fixed pressure, variable pulse frequency, and constant droplet diameter, and is sprayed into the grinding area in the form of a jet under the action of the air isolation layer generated by the high-pressure gas. It has all the advantages of minimal quantity lubrication technology, and has stronger cooling performance and excellent tribological characteristics, effectively solves the grinding burn, improves the surface quality of the workpiece, and realizes low-carbon green with high efficiency, low consumption, environmental friendliness and resource saving Cleaner production is of great significance.

Invention patent: Method and device for predicting grinding surface roughness by nanoparticle jet microlubrication (patent number 201210490401.0) discloses a method and device for predicting grinding surface roughness under nanoparticle jet microlubrication conditions. It includes a sensor lever, the left end of the sensor lever is provided with a stylus, the stylus is in contact with the surface of the grinding wheel, the right end of the sensor lever is connected to the inductive displacement sensor, and the fulcrum of the sensor lever is hinged with the body of the measuring device; the inductive displacement sensor is connected to the AC The power supply is connected; the data output end of the inductive displacement sensor is connected with the filter amplifier, the filter amplifier is respectively connected with the calculator and the oscilloscope, and the calculator is also connected with the memory. It uses a matrix to represent the shape of the grinding wheel, and then according to the mechanism of the surface shape of the grinding workpiece, the prediction model has high precision, not only convenient measurement, high equipment integration rate, high utilization rate, but also high measurement accuracy and good reliability. more instructive.

Invention patent: Three-phase flow supply system for nano-particle jet micro-lubrication grinding (patent number 201110221543.2) discloses a three-phase flow supply system for nano-particle jet micro-lubrication grinding. At the nozzle, the high-pressure gas enters the nozzle through the gas path at the same time, the high-pressure gas and the nanofluid are fully mixed and atomized in the nozzle mixing chamber, and then enter the vortex chamber after being accelerated by the acceleration chamber, and the compressed gas enters through the vent hole of the vortex chamber at the same time, so that the three-phase flow After further rotary mixing and acceleration, the three-phase flow is sprayed to the grinding zone through the nozzle outlet in the form of atomized droplets.

Invention patent: Nano-fluid electrostatic atomization controllable jet micro-lubrication grinding system (201310042095.9) discloses a nano-fluid electrostatic atomization controllable jet micro-lubrication grinding system, which can make sprayed droplets controllable through the principle of electrostatics distribution, thereby reducing the pollution to the environment and providing better health protection for the staff. Its grinding system is equipped with a corona charging nozzle, the nozzle body of the corona charging nozzle is connected to the liquid supply system and the gas supply system, and the high-voltage DC electrostatic generator at the bottom of the nozzle body is connected to the negative pole of the adjustable high-voltage DC power supply, which can The positive electrode of the high-voltage DC power supply is connected to the workpiece power supply device, and the workpiece power supply device is attached to the unprocessed surface of the workpiece; the nanofluid grinding fluid is sent to the corona charging nozzle through the liquid supply system, and the air supply system sends compressed air to Entering the corona charging nozzle, the nanofluid grinding fluid is driven by compressed air to spray out from the outlet of the nozzle body and atomize, and at the same time, it is charged by a high-voltage DC electrostatic generator to become a controllable jet, which can be controlled under the action of electric field force and pneumatic force. The distribution to the grinding area of the workpiece.

However, none of the above technical solutions is a grinding medium supply system coupled with low-temperature cooling and nano-particle jet microlubrication, so that it does not maximize the powerful convective heat transfer capacity of the low-temperature cooling medium and the excellent tribological properties of the nano-particle jet.

The inventors have shown through experimental research that the temperature of the grinding zone can be effectively controlled by using low-temperature CO2 and liquid nitrogen as the grinding cooling medium. Compared with dry grinding and pouring oil cooling grinding, liquid nitrogen low temperature cooling grinding force, specific grinding energy and grinding zone temperature are significantly reduced, the surface quality and integrity of the workpiece are significantly improved, and the use of grinding wheels is also significantly improved Life and reduce the pollution of the coolant to the environment. Cryogenic cooling has the following advantages:

(1) Low-temperature cooling grinding can effectively control the temperature of the grinding area, avoiding thermal damage, micro-cracks and tensile residual stress on the surface of the workpiece caused by excessive temperature, and improving the surface integrity of the workpiece;

(2) Compared with cooling oil grinding and dry grinding, low-temperature cooling grinding has significantly lower grinding force, which reduces the wear of the grinding wheel and improves the machining accuracy of the workpiece.

(3) With the increase of the grinding depth, the low-temperature cooling grinding reduces the specific grinding energy, which is beneficial to the reduction of the temperature in the grinding area.

(4) The low-temperature cooling grinding chips are mainly removed by shearing, which reduces the occurrence of sliding friction, plowing and plastic deformation, and improves the surface quality of the workpiece.

Although many scholars have carried out theoretical analysis and experimental research on nano-particle jet MQL grinding and cryogenic cooling cutting/grinding, and have done a lot of demonstrations and experiments. From the literature search, it can be seen that there is no organic combination of nano-particle jet micro-lubrication grinding and low-temperature cooling grinding, and the internal relationship between convective enhanced heat transfer in the grinding area and nano-particle jet and low-temperature cooling medium has not been established. The formation mechanism of the oil film on the surface of the workpiece under the coupling condition of the nanoparticle jet and the low-temperature cooling medium has not been established, and the advantages of the lubrication and heat dissipation of the nanoparticle jet and the low-temperature cooling medium on the grinding wheel/workpiece interface cannot be brought into play.

Contents of the invention

The object of the present invention is to solve the above problems, and provide a grinding medium supply system coupled with cryogenic cooling and nano-particle jet micro-lubrication. When grinding the workpiece material, the low-temperature cooling lubrication film can be formed in the grinding area by using the coupling method of nano-particle jet micro-lubrication and low-temperature cooling lubrication. During the grinding process, the low-temperature medium quickly evaporates and takes away a large amount of heat in the grinding area, which reduces the evaporation of the micro-lubricating grinding medium, and at the same time cools the surface of the workpiece and the grinding debris, improves the heat transfer capacity, and minimizes the grinding process. Cut heat damage, improve the surface integrity and machining accuracy of the processed workpiece. It has all the advantages of minimal quantity lubrication technology, and has stronger cooling performance and excellent tribological characteristics, effectively solves the grinding burn, improves the surface quality of the workpiece, and realizes low-carbon green with high efficiency, low consumption, environmental friendliness and resource saving Cleaner production is of great significance.

To achieve the above object, the present invention adopts the following technical solutions:

A grinding medium supply system coupled with low-temperature cooling and nano-particle jet micro-lubrication, which includes at least one micro-quantity lubrication and low-temperature cooling nozzle combination unit, which is arranged on the side of the grinding wheel cover of the grinding wheel and cooperates with the workpiece on the workbench; The unit includes a micro-quantity lubrication atomizing nozzle and a low-temperature cooling nozzle, the micro-lubricating atomization micro-nozzle is connected with a nanofluid pipeline and a compressed air pipeline, and the low-temperature cooling nozzle is connected with a low-temperature coolant pipeline; the nanofluid of each unit The pipelines, compressed air pipelines and low-temperature coolant pipelines are all connected to the nanofluid supply system, low-temperature medium supply system and compressed air supply system through control valves, and the nanofluid supply system, low-temperature medium supply system and compressed air supply system are connected with the control valve. device connection.

There are two combination units of minimal quantity lubrication and low-temperature cooling nozzles, which are respectively symmetrically installed on both sides of the grinding wheel cover. When working, the micro-lubrication atomizing nozzle and the low-temperature cooling nozzle on one side provide cooling and lubrication to the grinding area, and the micro-quantity lubrication atomizing nozzle on the other side only sprays compressed air for cleaning and chip removal, and the low-temperature cooling nozzle is closed.

The nanofluid supply system includes a nanofluid liquid storage tank, which is connected to the corresponding control valve through a hydraulic pump II, a pressure regulating valve II, a throttle valve II, and a turbine flowmeter II;

The compressed air supply system includes an air compressor, which is connected to the corresponding control valve through a filter, an air storage tank, a pressure regulating valve III, a throttle valve III, and a turbine flowmeter III;

The low-temperature medium supply system includes a low-temperature medium liquid storage tank, which is connected to the corresponding control valve through a hydraulic pump I, an oil-water separator, a pressure regulating valve I, a throttle valve I, and a turbine flowmeter I.

The pressure regulating valve II is also connected with the overflow valve II and the nanofluid recovery tank;

The pressure regulating valve III is also connected with the overflow valve III and the compressed air recovery tank;

The pressure regulating valve 1 is also connected with the overflow valve 1 and the low temperature medium recovery box.

The control valve is a manual reversing valve of a four-position six-way valve. The valve body is provided with a compressed air inlet _T1 , a nanofluid inlet P, and a liquid cryogenic medium inlet _T2 , as well as a compressed air outlet A, a nanofluid outlet B and a liquid cryogenic medium. Medium outlet C; the valve core is positioned by a spring steel ball, and there is a tapered sealing internal thread at the left end of the axial hole of the valve core, which is sealed with a tapered sealing screw during installation. The sealing screw is a tapered screw with fine thread. Apply sealant to threads.

The micro-quantity lubrication atomizing micro-quantity nozzle includes a mixing chamber, one section of the mixing chamber is equipped with an air injection pipe, and the other end is installed with a spray head; the air injection pipe is assembled with the mixing chamber through the left nut and sealing washer 1, and the spray head is passed through the right nut and sealing washer II is assembled with the mixing chamber; the liquid inlet plug divides the mixing chamber into a liquid inlet chamber and a mixing chamber, the mixing chamber is connected to the acceleration section, and the acceleration section is connected to the nozzle; A section of the side wall of the mixing chamber is provided with a number of swirling air holes, and the top of the gas injection pipe is provided with an air outlet.

The liquid inlet plug is disc-shaped, with 4-8 liquid inlet holes symmetrically distributed around it; 4-8 spiral air holes are arranged along the wall array of the gas injection pipe, and the outlet axis is aligned with the inner wall of the gas injection chamber. Cut, the compressed gas enters into the mixing chamber 48 at a tangential velocity v through the swirling air hole, and impels the air flow to rotate around the gas injection pipe in the mixing chamber, thereby driving the nanofluid to rotate to form a vortex; the axial angle between the swirling air hole and the gas injection pipe is δ=25-75° and inclined to the nozzle outlet.

The nozzle is a flat fan-shaped nozzle, and the inner surface of the flat fan-shaped nozzle is a semi-ellipsoid or a hemispherical surface; a V-shaped groove is opened on the top of the semi-ellipsoid, and the two slopes of the V-shaped groove are symmetrical about the axis of the nozzle and formed by intersecting with the semi-ellipsoid For a long and narrow spout, the slope angle α is half the angle of the V-shaped groove.

The low-temperature cooling nozzle is an integrated duckbill nozzle, the total length of the nozzle is Dz=25-55mm, the inlet size of the front section of the nozzle is dr×hr, and the outlet size is dc×hc, wherein dr is 10-40mm, hr is 5- 35mm, 20-50mm for dc, 15-45mm for hc.

The injection distance from the micro-lubrication atomizing micro-quantity nozzle to the workpiece in each micro-lubrication and low-temperature cooling nozzle combination unit is d, which is 10-20cm, and the injection angle is β, which is 15-30°; the injection flow rate is 2.5-3.2 ml/min, the pressure of compressed air is 4.0-10bar;

The vertical distance from the cryogenic cooling nozzle to the workpiece is h, which is 2-5cm; the spray angle is γ, which is 3-8°; the flow rate of the liquid cryogenic medium is 10-40L/min.

The beneficial effect of the present invention is to provide a grinding medium supply system coupled with low-temperature cooling and nano-particle jet micro-lubrication, the system has two sets of nozzles, the micro-quantity lubrication atomization nozzle I and the low-temperature cooling nozzle I are fixed on the right side of the grinding wheel, The cryogenic cooling nozzle II and the minimum quantity lubrication atomizing nozzle II are fixed on the left side of the grinding wheel. When grinding ordinary materials, such as 45 steel, the manual reversing valve I is adjusted to the second working position, and the nanofluid in the nanofluid storage tank flows sequentially under the action of the hydraulic pump II. After the pressure regulating valve II, throttle valve II, turbine flowmeter II, and then through the manual reversing valve I, it enters the micro-lubrication atomizing nozzle I. Flow valve Ⅲ, turbine flowmeter Ⅲ, then flow through the manual reversing valve Ⅰ and enter the micro-lubrication atomization nozzle Ⅰ to perform nano-particle jet micro-lubrication on the grinding area, and at the same time adjust the manual reversing valve Ⅱ to the third working position, compress After the air flows out of the air storage tank, it flows through the pressure regulating valve III, the throttle valve III, the turbine flowmeter III, and then flows through the manual reversing valve II and enters the micro-lubrication atomizing nozzle II to remove chips from the grinding wheel and the workpiece. When backgrinding 45 steel, exchange the working positions of the manual reversing valve I and the manual reversing valve II. When performing smooth grinding on difficult-to-machine materials, such as nickel-based alloys, the manual reversing valve I is adjusted to the first working position, and the nanofluid in the nanofluid storage tank is released under the action of the hydraulic pump II. It flows through the pressure regulating valve II, throttle valve II, turbine flowmeter II in sequence, and then flows through the manual reversing valve I and enters the micro-lubrication atomizing nozzle I. The compressed air flows out of the air storage tank and then flows through the pressure regulating valve III in sequence. , throttle valve Ⅲ, turbine flowmeter Ⅲ, then flow through the manual reversing valve Ⅰ and enter the micro-lubrication atomization nozzle Ⅰ, and the low-temperature medium in the low-temperature medium liquid storage tank flows through the oil-water separator in sequence under the action of the hydraulic pump Ⅰ , pressure regulating valve Ⅰ, throttle valve Ⅰ, and turbine flowmeter Ⅰ then flow through the manual reversing valve Ⅰ and enter the low-temperature cooling nozzle Ⅰ, and carry out nano-particle jet microlubrication and low-temperature cooling coupled cooling lubrication on the grinding area. Adjust the directional valve Ⅱ to the third working position. After the compressed air flows out of the air storage tank, it flows through the pressure regulating valve Ⅲ, the throttle valve Ⅲ, the turbine flowmeter Ⅲ, and then flows through the manual directional valve Ⅱ to enter the micro-lubrication atomization Nozzle II, for chip removal and cleaning of the grinding wheel and workpiece. When backgrinding nickel-based alloys, exchange the working positions of manual reversing valve I and manual reversing valve II.

When grinding difficult-to-machine materials, the method of coupling nanoparticle jet microlubrication and cryogenic cooling lubrication can form a low-temperature frozen lubricating film in the grinding area. During the grinding process, the low-temperature medium liquid quickly evaporates and takes away a large amount of heat in the grinding area, which reduces the evaporation of the micro-lubricating grinding fluid, and cools the surface of the workpiece and the grinding debris at the same time. According to the principle of the capillary in the grinding area, in ordinary minimal quantity lubrication and traditional pouring lubrication, the liquid cooling lubricant penetrates into the capillary in three stages. Under the action of the temperature in the grinding zone, the grinding fluid evaporates and “explodes”. The third stage is the gas phase filling. The explosive gas fills the capillary, hindering the subsequent entry of grinding fluid, thereby reducing the grinding fluid’s Cooling and lubricating properties. When low-temperature cooling and lubrication are used at the same time, the heat taken away by the evaporation of the low-temperature medium liquid avoids the "explosion" of the micro-lubricant in the capillary or the rapid cooling of the vapor after the "explosion", ensuring the entry of subsequent grinding fluid to play Good cooling and lubricating performance of grinding fluid. This is very beneficial for grinding difficult-to-machine materials.

Description of drawings:

Fig. 1 is the general assembly axonometric view of this embodiment;

Fig. 2 is a schematic diagram of the system of the micro-lubrication gas circuit, liquid circuit and low-temperature cooling liquid circuit of this embodiment;

Fig. 3 is the structural diagram of manual reversing valve in this embodiment;

Fig. 4 is the working principle figure of manual reversing valve in this embodiment;

Fig. 5 is a sectional view of the assembly of the minimal quantity lubrication atomizing nozzle of this embodiment;

Figure 5a is a partial sectional view of the gas injection tube;

Fig. 6 is a cross-sectional view of the micro-quantity lubrication atomizing nozzle in this embodiment;

Fig. 7 is a sectional view of the nozzle of this embodiment;

Fig. 8 is the structural diagram of the cryogenic cooling nozzle of this embodiment;

Fig. 8 a is the positive two side views of the cryogenic cooling nozzle of this embodiment;

Figure 8b is a left side view of the cryogenic cooling nozzle of this embodiment;

Figure 8c is a top view of the cryogenic cooling nozzle of this embodiment;

Fig. 9 is a schematic diagram of the relative positions of the two kinds of nozzles and the workpiece in this embodiment.

Among them, 1-part workbench, 2-workpiece, 3-grinding wheel, 4-grinding wheel cover, 5-magnetic fixed suction cup, 6-low temperature medium delivery tube, 7-nanometer fluid delivery tube, 8-compressed air delivery tube, 9- Minimal quantity lubrication atomizing nozzle Ⅰ, 10-low temperature cooling nozzle Ⅰ, 11-nano fluid storage tank, 12-air compressor, 13-low temperature medium liquid storage tank, 14-hydraulic pump Ⅰ, 15-filter, 16-nanometer Fluid recovery tank, 17-oil-water separator, 18-hydraulic pump Ⅱ, 19-pressure gauge Ⅳ, 20-pressure regulating valve Ⅲ, 21-pressure regulating valve Ⅱ, 22-pressure regulating valve Ⅰ, 23-overflow valve Ⅱ, 24-throttle valve III, 25-throttle valve II, 26-throttle valve I, 27-turbine flowmeter III, 28-turbine flowmeter II, 29 turbine flowmeter I, 30-air storage tank, 31-manual Reversing valve Ⅰ, 32-valve body, 33-spool, 34-left nut, 35-injection pipe, 36-sealing washer Ⅰ, 37-inlet threaded pipe, 38-inlet plug, 39-right nut, 40 -Sealing gasket II, 41-spray head, 42-mixing chamber, 43-minimum quantity lubrication atomizing nozzle II, 44-low temperature cooling nozzle II, 45-manual reversing valve II, 46-inlet chamber, 47-inlet chamber , 48-mixing chamber, 49-acceleration section, 50-nozzle outlet, 51-relief valve Ⅲ, 52-relief valve Ⅰ, 53-pressure gauge Ⅰ, 54-pressure gauge Ⅱ, 55-pressure gauge Ⅲ, 56- Compressed air recovery box, 57-low temperature medium recovery box, 58-sealing screw.

Detailed ways:

Below in conjunction with accompanying drawing and embodiment the present invention is described:

It can be seen from Figure 1 that there are two sets of nozzles in this embodiment, which are the micro-lubrication atomization nozzle I9 and the low-temperature cooling nozzle I10 on the right side of the grinding wheel, and the micro-lubrication atomization nozzle II43 and the low-temperature cooling nozzle II44 on the left side of the grinding wheel. . The minimal quantity lubrication atomizing nozzle I9 is connected with the nanofluid delivery pipe 7 and the compressed air delivery pipe 8 , and the low-temperature cooling nozzle I10 is connected with the low-temperature medium delivery pipe 6 . The minimal quantity lubrication atomizing nozzle II43 and the low-temperature cooling nozzle II44 are also connected to the delivery pipe on the other side. The magnetic fixed suction cup 5 is adsorbed on the side of the grinding wheel 3 and is used to fix the nanofluid delivery tube 7 , the compressed air delivery tube 8 and the cryogenic medium delivery tube 6 . Minimal quantity lubrication atomizing nozzle I9 and minimal quantity lubrication atomizing nozzle II43 provide minimal quantity lubrication for the grinding zone between the grinding wheel 3 and the workpiece 2 . The low-temperature cooling nozzle I10 and the low-temperature cooling nozzle II44 can provide low-temperature cooling and lubrication for the grinding zone between the grinding wheel 3 and the workpiece 2 . Minimal quantity lubrication atomizing nozzle Ⅰ9 and low-temperature cooling nozzle Ⅰ10 can provide cooling and lubrication to the grinding area during smooth grinding, and the microlubrication atomizing nozzle Ⅱ43 on the other side only sprays compressed air for cleaning and chip removal, and low-temperature cooling nozzle Ⅱ44 is closed. Conversely, when reverse grinding, the micro-lubrication atomizing nozzle II43 and the low-temperature cooling nozzle II44 can provide cooling and lubrication to the grinding area, and the micro-lubrication atomizing nozzle I9 on the other side only sprays compressed air to clean and remove chips, and the low-temperature cooling nozzle I10 is closed.

As shown in the system diagram of the minimal quantity lubrication gas circuit, liquid circuit and low-temperature cooling liquid circuit in this embodiment of Figure 2, the air compressor 12 produces compressed air, which is stored in the air storage tank 30 after passing through the filter 15, and is controlled by the pressure Table IV19 detects the pressure in the air storage tank 30. After the compressed air flows out of the air storage tank 30, it flows through the pressure regulating valve III20, throttle valve III24, turbine flowmeter III27 in sequence, and then flows through the manual reversing valve I31 to enter the minimum quantity lubrication The atomizing nozzle I9 or flows through the manual reversing valve II45 and enters the minimal quantity lubrication atomizing nozzle II43. The overflow valve III51 and the compressed air recovery tank 56 constitute a protection circuit. Under the action of the hydraulic pump II18, the nanofluid in the nanofluid storage tank 11 flows through the pressure regulating valve II21, the throttle valve II25, and the turbine flowmeter II28 in sequence, and then flows through the manual reversing valve I31 and enters the micro-quantity lubrication atomizing nozzle I9 or flows through the manual reversing valve II45 and enters the micro-lubrication atomizing nozzle II43, while the overflow valve II23 and the nanofluid recovery tank 16 form a protection circuit. Under the action of the hydraulic pump I14, the low-temperature medium in the low-temperature medium liquid storage tank 13 flows through the oil-water separator 17, the pressure regulating valve I22, the throttle valve I26, the turbine flowmeter I29, and then flows through the manual reversing valve I31 to enter the low-temperature medium. The cooling nozzle I10 or the flow through the manual reversing valve II45 enters the low-temperature cooling nozzle II44. The overflow valve I52 and the low-temperature medium recovery tank 57 constitute a protection circuit. Pressure gauge I53, pressure gauge II54 and pressure gauge III55 are used to monitor the pressure of the cryogenic medium passage, nanofluid passage and compressed gas passage respectively.

As shown in Figures 3 and 4, the structure and working principle diagram of the manual reversing valve in this embodiment, it can be seen that the valve is a four-position six-way valve, and there are three inlets on the valve body 32, which are respectively compressed air inlets _T1 , the nanofluid inlet P and the liquid cryogenic medium inlet T ₂ . The three outlets on the valve body 32 are compressed air outlet A, nanofluid outlet B and liquid cryogenic medium outlet C. 1 and 2, it can be seen that the compressed air inlet _T1 is connected to the compressed air delivery pipe 8, the nanofluid inlet P is connected to the nanofluid delivery pipe 7, and the liquid cryogenic medium inlet _T2 is connected to the cryogenic medium delivery pipe 6. The compressed air outlet A and the nanofluid outlet B are connected to the compressed air inlet and the nanofluid inlet of the minimum quantity lubrication atomization nozzle I9 and the minimum quantity lubrication atomization nozzle II43, and the liquid low temperature medium outlet C is connected to the low temperature cooling nozzle I10 and the low temperature cooling nozzle II44 . It can be seen from the figure that the valve is a valve with a spring steel ball positioning structure. When the handle is released, the valve still remains at the desired working position. The valve has four working positions. When the valve is in the first working position, minimum quantity lubrication and low-temperature cooling lubrication will be carried out at the same time. When the valve is in the second working position, only minimal lubrication is performed, and low-temperature cooling lubrication stops. When the valve is in the fourth working position, all passages are cut off, and the system is in a stop working state. When the valve is in the third working position, the compressed air enters through the passage in the valve core 33 from the inlet _T1 and then flows out from the outlet B. At this time, only spraying compressed air can clean the MQL spray nozzle I9 and the MQL atomizer The function of the nanofluid channel in the nozzle II 43 can also clean the workpiece surface. Visible in the figure has the taper sealing internal thread at the left end of spool 33 axial holes, seals with taper sealing screw 58 when installing, and sealing screw 58 is the taper screw of fine thread, smears sealant at thread place when sealing.

As shown in the sectional view of the assembly of the minimal quantity lubrication atomizing nozzle of this embodiment in Fig. 5, it can be seen that the minimum quantity lubrication atomizing nozzle I9 and the minimum quantity lubrication atomizing nozzle II 43 designed and used in this embodiment are composed of the left nut 34 and the gas injection pipe 35 , sealing washer I36, liquid inlet threaded pipe 37, liquid inlet plug 38, right nut 39, sealing washer II40, nozzle 41 and mixing chamber 42, the assembly is shown in Figure 5. It can be seen from the figure that the MQL atomizing nozzle I9 and the MQL atomizing nozzle II43 also include an air inlet chamber 46 , a liquid inlet chamber 47 , a mixing chamber 48 , an acceleration section 49 and a nozzle outlet 50 . Compressed air and nanofluid enter the mixing chamber after passing through the air inlet chamber 46 and the liquid inlet chamber 47 respectively for mixing. The liquid inlet plug 38 is disc-shaped, and 4-8 liquid inlet holes can be symmetrically distributed around as required, so that the The compressed air and the nanofluid have sufficient mixing space in the mixing chamber 48 . The compressed air and the nano fluid are fully mixed in the mixing chamber 48 to form a subsonic three-phase (compressed air, liquid lubricating base oil and solid nano particles) bubble flow. After the bubbly flow enters the acceleration section, the conical structure of the acceleration section reduces the flow space of the three-phase bubbly flow, thereby increasing the pressure and velocity of the three-phase bubbly flow, and reducing the bubble diameter. At the same time, when the three-phase bubble flow passes through the acceleration section, it is squeezed and becomes unstable, and breaks into smaller bubbles and droplets, which increases the number of droplets and improves the atomization effect. At the same time, the three-phase bubbly flow is accelerated and ejected at near-sonic speed at the nozzle mouth, which increases the jet velocity. When the pressure suddenly drops to the ambient pressure, the bubbles expand rapidly and explode to form the power of liquid atomization, and the surrounding bubbles will be affected by the shock wave and explode. And collide with each other to make the atomized particles extremely small.

As shown in the cross-sectional view of the swirling air holes of the minimal quantity lubrication atomizing nozzle in this embodiment of Fig. 6, the main feature of the swirling air holes is that they are located on the side of the gas injection pipe 35, and 4-8 are arranged in an array along the pipe wall according to actual needs. The axis is tangent to the inner cavity wall of the gas injection pipe 35, and the compressed gas enters the mixing chamber 48 at a certain tangential velocity v through the vent hole. The fluid swirls to form a vortex. At the same time, it can be seen from Figure 5a that these swirling vent holes are inclined to the nozzle outlet at an angle of δ (25-75°) to the axial direction, which can promote the three-phase bubble flow to advance to the nozzle hole, and at the same time, there is An air outlet, which can accelerate the mixed three-phase bubbly flow.

As shown in the sectional view of the spray head of this embodiment in FIG. 7 , it can be seen that the spray head 41 is a flat fan-shaped spray head. The inner surface of the flat fan nozzle is usually a semi-ellipsoid or a hemisphere. A V-shaped groove is opened on the top of the semi-ellipsoid, and the two slopes of the V-shaped groove are symmetrical to the nozzle axis and intersect with the semi-ellipsoid to form a long and narrow nozzle. This nozzle can produce fan-shaped uniform flat jet flow, which has uniform impact force, large impact range, and the diffusion angle can also be adjusted within a wide range, and its cleaning ability is particularly outstanding. Therefore, when the surface of the workpiece is cleaned with compressed air, the effect is particularly obvious. In the figure, a is the length of the semi-major axis of the ellipse, b is the length from the center of the ellipse to the bottom of the V-shaped groove, c is the diameter of the incident section of the nozzle, and α is half of the angle of the V-shaped groove.

As shown in the structural diagram of the low-temperature cooling nozzle of this embodiment in FIG. 8 , this kind of cooling nozzle is an integrated nozzle with a simple structure, simple processing and low cost. According to Figure 8a, Figure 8b and Figure 8c, it can be seen that the total length of the nozzle is Dz (25-55mm), the inlet size of the front section of the nozzle is dr×hr, and the outlet size is dc×hc, where dr is 10-40mm and hr is 5 -35mm, dc can be 20-50mm, hc can be 15-45mm, the thread at the rear end can be selected according to different requirements according to thread specifications such as M36, M24 and M40, and the thread at the rear end is connected with the low-temperature medium delivery pipe 6. The liquid flow space inside the duckbill nozzle tends to decrease slowly, so that the outlet liquid has a certain speed. This type of nozzle is suitable for larger flow liquids and is not easy to clog.

As shown in the schematic diagram of the relative positions of the two nozzles and the workpiece in this embodiment of Fig. 9, the spraying distance from the minimal quantity lubrication atomizing nozzle I9 to the workpiece 2 is d, which is generally 10-20 cm. The spray angle of the minimal quantity lubrication atomizing nozzle I9 is β, which is generally 15-30°. The vertical distance from the cryogenic cooling nozzle I10 to the workpiece 2 is h, generally 2-5cm, and the spray angle of the cryogenic cooling nozzle I10 is γ, generally 3-8°. Minimal quantity lubrication atomizing nozzle II43 and low temperature cooling nozzle II44 are installed symmetrically with the minimum quantity lubrication atomizing nozzle I9 and low temperature cooling nozzle I10 on the grinding wheel twice. At the same time, the injection flow rate of the minimum quantity lubrication atomization nozzle Ⅰ9 and the minimum quantity lubrication atomization nozzle Ⅱ43 is 2.5-3.2ml/min, the pressure of the compressed air is 4.0-10bar, and the flow rate of the liquid low-temperature medium of the low-temperature cooling nozzle Ⅰ10 and the low-temperature cooling nozzle Ⅱ44 is 10- 40L/min.

The specific working process of this program is as follows:

Minimal quantity lubrication technology has been widely concerned by scholars at home and abroad, and the technology is becoming more and more mature, and has been more and more applied in production and processing. The technology of adding nanoparticles to the micro-lubricating fluid to form a jet of nanoparticles to cool and lubricate the grinding area has also achieved relatively ideal results. However, as difficult-to-machine materials such as titanium-based alloys, nickel-based alloys, stainless steel, magnesium-based alloys, and composite materials play an increasingly important role in important fields such as aviation industry, automobile industry, nuclear energy industry, and biomedicine, micro-quantity lubrication technology and nanoparticles Jet technology is not ideal for cooling and lubrication when grinding some difficult-to-machine materials.

Due to the high grinding force and specific grinding energy, the grinding process generates a lot of heat in the grinding area. Since the metal layer to be cut is relatively thin, about 60%-90% of the heat is transferred to the workpiece, and only less than 10% of the heat is taken away by the grinding debris, and the heat introduced into the workpiece is often too late to be transmitted into the depth of the workpiece during the grinding process, and it gathers in the surface layer to form a local high temperature, and the surface temperature of the workpiece can often reach above 1000 °C. Such a high temperature can easily cause problems with the surface accuracy and geometric dimension accuracy of the workpiece, and in severe cases, it will cause burns on the surface of the workpiece. Nano particle jet microlubrication can play a better role in cooling and lubrication in general grinding. When processing difficult-to-machine materials, due to a series of characteristics such as low thermal conductivity, high hardness and thermal strength, and high work hardening performance of difficult-to-machine materials, the temperature in the grinding zone will increase sharply, the grinding force will increase sharply, and the grinding wheel will wear The sharp increase, the surface quality of the workpiece will drop sharply, and even explosion, combustion, etc. will occur.

Theoretically, the material exhibits high strength, high hardness, high ductility, high adhesion, low thermal conductivity, and flammability and reaction, one or more of which are called difficult-to-process materials. Such as titanium-based alloys and nickel-based alloys, their thermal conductivity is very low, and the abrasive debris generated during grinding is not enough to take away a large amount of heat. At the same time they have high hardness and thermal strength, and high work hardening properties, which lead to a sharp increase in grinding force, which in turn leads to a further increase in temperature in the grinding zone. Conventional grinding fluids cannot penetrate to the contact surface between the grinding chip and the grinding wheel and reach the highest temperature area especially at high speed grinding. The grinding fluid evaporates in the high temperature zone and forms a high temperature cover film in the grinding zone which leads to a further increase in temperature. Although the nanoparticle jet can enter the grinding area driven by compressed air, it cannot form an effective cooling lubricating film due to the high temperature and high grinding force in the grinding area. The amount of nano particle jet is very small, and a small amount of lubricating oil will evaporate in large quantities under the action of ultra-high temperature in the grinding area, and the oil film formed is not ideal. Difficult-to-machine materials such as titanium-based alloys and nickel-based alloys should pay special attention to controlling the temperature in the grinding area during processing. When the temperature in the grinding area exceeds a certain temperature, combustion or various problems will occur during processing, such as titanium Base alloy processing should be controlled within 400 °C. Titanium-based alloys and nickel-based alloys are very reactive to all known tool materials. The performance of this reaction increases at higher temperatures, which will lead to phenomena such as sticking, which will block the pores of the grinding wheel, which will seriously affect the performance and life of the grinding wheel. As a result, the environment in the grinding area is further deteriorated, and the final performance is poor surface quality of the workpiece, poor geometric accuracy of the workpiece, poor wear debris formation ability, sharp wear of the grinding wheel or even failure.

For magnesium-based alloys, we believe that magnesium-based alloys are easy-to-machine structural materials due to low grinding force, high surface finish, easy formation of wear debris, and long service life of grinding wheels. Magnesium-based alloys are however highly flammable materials whose danger of burning increases with temperature above 450°C to its melting point of 650°C. Magnesium-based alloys can burn in different gases such as nitrogen, carbon dioxide, water vapor, etc. even in the absence of oxygen. Therefore, in order to ensure that no combustion occurs, it is very critical to control the cutting temperature during machining. The presence of flammable grinding debris in the grinding area further increases the risk of fire in the workplace, so it is very important to remove grinding debris from the workpiece material from the grinding wheel and workpiece during machining, which requires grinding systems with Good cleaning function.

Based on the above problems, this invention proposes a grinding medium supply system coupled with low-temperature cooling and nano-particle jet micro-lubrication. The system has two sets of nozzles, the micro-quantity lubrication atomization nozzle I9 and the low-temperature cooling nozzle I10 are fixed on the right side of the grinding wheel. The cryogenic cooling nozzle II44 and the minimal quantity lubrication atomizing nozzle II43 are fixed on the left side of the grinding wheel. When grinding ordinary materials, such as 45 steel, the manual reversing valve Ⅰ31 is adjusted to the second working position, and the nanofluid in the nanofluid liquid storage tank 11 is under the action of the hydraulic pump Ⅱ18. It flows through pressure regulating valve Ⅱ21, throttle valve Ⅱ25, turbine flowmeter Ⅱ28, then flows through manual reversing valve Ⅰ31 and enters micro-lubrication atomizing nozzle Ⅰ9, and the compressed air flows out of air storage tank 30 and then flows through pressure regulating valve Ⅲ20 , throttle valve Ⅲ24, turbine flowmeter Ⅲ27, and then flow through the manual reversing valve Ⅰ31 into the micro-lubrication atomization nozzle Ⅰ9 to perform nano-particle jet micro-lubrication on the grinding area, and at the same time adjust the manual reversing valve Ⅱ45 to the third working position , the compressed air flows out of the air storage tank 30 and then flows through the pressure regulating valve III20, the throttle valve III24, the turbine flowmeter III27, and then flows through the manual reversing valve II45 and enters the micro-lubrication atomizing nozzle II43 to discharge the grinding wheel and the workpiece. crumb cleaning. When backgrinding 45 steel, exchange the working positions of the manual reversing valve I31 and the manual reversing valve II45. When grinding hard-to-machine materials, such as nickel-based alloys, the manual reversing valve I31 is adjusted to the first working position, and the nanofluid in the nanofluid storage tank 11 is under the action of the hydraulic pump II18 , flows through the pressure regulating valve II21, throttle valve II25, turbine flowmeter II28 in sequence, and then flows through the manual reversing valve I31 and enters the micro-lubrication atomizing nozzle I9. The compressed air flows out of the air tank 30 and then flows through the pressure regulating Valve Ⅲ20, throttle valve Ⅲ24, turbine flowmeter Ⅲ27, and then flow through the manual reversing valve Ⅰ31 to enter the micro-lubrication atomizing nozzle Ⅰ9, and the low-temperature medium in the low-temperature medium liquid storage tank 13 flows through it in turn under the action of the hydraulic pump Ⅰ14 The oil-water separator 17, the pressure regulating valve I22, the throttle valve I26, and the turbine flowmeter I29 flow through the manual reversing valve I31 and enter the low-temperature cooling nozzle I10, and carry out nano-particle jet micro-lubrication and low-temperature cooling coupling cooling lubrication on the grinding area, At the same time, adjust the manual reversing valve II45 to the third working position, the compressed air flows out from the air storage tank 30 and then flows through the pressure regulating valve III20, the throttle valve III24, the turbine flowmeter III27, and then flows through the manual reversing valve II45 Enter the minimal quantity lubrication atomizing nozzle Ⅱ43 to clean the grinding wheel and the workpiece for chip removal. When backgrinding nickel-based alloys, exchange the working positions of the manual reversing valve I31 and the manual reversing valve II45.

When grinding difficult-to-machine materials, the method of coupling nanoparticle jet microlubrication and cryogenic cooling lubrication can form a low-temperature frozen lubricating film in the grinding area. During the grinding process, the low-temperature medium liquid quickly evaporates and takes away a large amount of heat in the grinding area, which reduces the evaporation of the micro-lubricating grinding fluid, and cools the surface of the workpiece and the grinding debris at the same time. According to the principle of the capillary in the grinding area, in ordinary minimal quantity lubrication and traditional pouring lubrication, the liquid cooling lubricant penetrates into the capillary in three stages. Under the action of the temperature in the grinding zone, the grinding fluid evaporates and “explodes”. The third stage is the gas phase filling. The explosive gas fills the capillary, hindering the subsequent entry of grinding fluid, thereby reducing the grinding fluid’s Cooling and lubricating properties. When low-temperature cooling and lubrication are used at the same time, the heat taken away by the evaporation of the low-temperature medium liquid avoids the "explosion" of the micro-lubricant in the capillary or the rapid cooling of the vapor after the "explosion", ensuring the entry of subsequent grinding fluid to play Good cooling and lubricating performance of grinding fluid. This is very beneficial for grinding difficult-to-machine materials.

Claims (9)

1. a sub-cooled is coupled with nano particle jet micro lubricating grinding medium feed system, it is characterized in that, it comprises at least one micro lubricating and sub-cooled Nozzle combination unit, and this unit is arranged on the wheel guard side of emery wheel, and matches with the workpiece on workbench; Described unit comprises micro lubricating and is atomized micro-nozzle and sub-cooled nozzle, and micro lubricating is atomized micro-nozzle and is connected with nano-fluid pipeline and compressed air line, and sub-cooled nozzle is connected with sub-cooled liquid pipeline; Nano-fluid pipeline, the compressed air line of each unit are all connected with nano-fluid feed system, cryogenic media feed system and compressed-air supply system by control valve with sub-cooled liquid pipeline, and nano-fluid feed system, cryogenic media feed system are connected with control device with compressed-air supply system;

Described micro lubricating is atomized micro-nozzle and comprises mixing chamber, and mixing chamber one section installs air injection pipe, other end mounting spray head; Air injection pipe is assembled together by left nut and seal washer I and mixing chamber, and shower nozzle is assembled together by right nut and seal washer II and mixing chamber; Mixing chamber is divided into admission chamber and hybrid chamber by feed liquor plug, and hybrid chamber is connected with accelerating sections, and accelerating sections is connected with shower nozzle; Feed liquor screwed pipe is communicated with admission chamber, and one section of sidewall that air injection pipe is positioned at hybrid chamber is provided with some rotation direction pores, and air injection pipe top is then provided with venthole.

2. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, and it is characterized in that, described micro lubricating and sub-cooled Nozzle combination unit have two, respectively the both sides being arranged on wheel guard of symmetry; During work, micro lubricating atomizer and the sub-cooled nozzle of side provide cooling and lubricating to grinding area, and the micro lubricating atomizer of opposite side only sprays compressed air and carries out cleaning chip removal, and sub-cooled nozzle is closed.

3. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, it is characterized in that, described nano-fluid feed system comprises nano-fluid fluid reservoir, and it is connected with corresponding control valve by hydraulic pump II, pressure regulator valve II, choke valve II, turbine flowmeter II;

Described compressed-air supply system comprises air compressor, and it is connected with corresponding control valve by filter, air accumulator, pressure regulator valve III, choke valve III, turbine flowmeter III;

Described cryogenic media feed system comprises cryogenic media fluid reservoir, and it is connected with corresponding control valve by hydraulic pump I, oil water separator, pressure regulator valve I, choke valve I, turbine flowmeter I.

4. sub-cooled as claimed in claim 3 is coupled with nano particle jet micro lubricating grinding medium feed system, and it is characterized in that, described pressure regulator valve II is also connected with overflow valve II, nano-fluid collection box; Described pressure regulator valve III is also connected with overflow valve III and compressed air collection box; Described pressure regulator valve I is also connected with overflow valve I, cryogenic media collection box.

5. the sub-cooled as described in claim 1 or 3 is coupled with nano particle jet micro lubricating grinding medium feed system, it is characterized in that, described control valve is the hand-operated direction valve of four six-way valves, and valve body is provided with compressed air inlet T1, nano-fluid entrance P and liquid low temperature medium inlet T2 and compressed air outlet A, nano-fluid outlet B and liquid low temperature media outlet C; Spool adopts spring steel ball location, has cone seal internal thread at the left end of spool axial hole, and when mounted with the sealing of cone sealing screw, sealing screw is fine thread cone screw, is coated with fluid sealant when sealing at screw thread place.

6. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, and it is characterized in that, described feed liquor plug is disc, around symmetrical 4-8 inlet opening; Described rotation direction pore is along tube wall array arrangement 4-8 of air injection pipe, outlet axes and its gas injection cavity wall face tangent, Compressed Gas enters in hybrid chamber 48 with tangential velocity v through rotation direction pore, impels air-flow to rotate around air injection pipe in hybrid chamber, thus drives nano-fluid to rotate formation eddy current; Rotation direction pore and air injection pipe are axially angled °-75 °, δ=25 and tilt to spray outlet.

7. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, and it is characterized in that, described shower nozzle is flat fan shower nozzle, and flat fan shower nozzle inner surface is semielliptical or hemisphere face; Open a V-shaped groove on the top of semielliptical, V-shaped groove two inclined-plane is about shower nozzle axisymmetrical and become long and narrow spout with semiellipse ball intersecting shape, and bevel angle α is the half of V-shaped groove angle.

8. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, it is characterized in that, described sub-cooled nozzle is integral type Duckbill type nozzle, nozzle total length degree is Dz=25-55mm, and nozzle leading portion entrance opening dimension is dr × hr, and outlet size is dc × hc, wherein dr gets 10-40mm, hr gets 5-35mm, and dc gets 20-50mm, and hc gets 15-45mm.

9. sub-cooled as claimed in claim 1 is coupled with nano particle jet micro lubricating grinding medium feed system, it is characterized in that, in described micro lubricating and sub-cooled Nozzle combination unit, micro lubricating is atomized micro-nozzle to the jet length of workpiece is d, get 10-20cm, spray angle is β, and value is 15 °-30 °; Injection flow is 2.5-3.2ml/min, and compressed-air actuated pressure is 4.0-10bar;

Described sub-cooled nozzle is h to the vertical range of workpiece, gets 2-5cm, and spray angle is γ, and value is 3 °-8 °; Liquid low temperature rate-of flow is 10-40L/min.