Heat dissipation cooling system for ball screw nut of machine tool

Abstract

The invention discloses a heat dissipation and cooling system for a ball screw nut of a machine tool. The heat dissipation and cooling system comprises cooling liquid, a cooling liquid circulation subsystem and a cooling liquid cooling subsystem. The cooling liquid circulation subsystem comprises a cooling input pipeline and a cooling output pipeline, one end of the cooling input pipeline is connected with the water tank, and the other end is connected with an inlet of the axial heat dissipation channel; one end of the cooling output pipeline is connected with the water tank, and the other end is connected with an outlet of the axial radiating channel; a hydraulic pump and a flow control valve are arranged on the cooling input pipeline; a radiator is arranged on the cooling output pipeline, an S-shaped radiating pipe is arranged on the radiator, and the S-shaped radiating pipe is connected with the cooling liquid cooling subsystem. The axial water channel is designed for the ball screw nut of the machine tool, and cooling liquid is uniformly cooled in the nut, so that the phenomena of heat source generation and thermal expansion during high-speed operation of the ball screw nut are reduced, high-precision and high-speed operation of the ball screw nut is ensured, the precision maintainability of the machine tool is enhanced, and the service life of the machine tool is prolonged. The machining precision degradation of the machine tool is prevented.

Description

Technical Field

[0001] The invention relates to the field of thermal deformation compensation of precision machinery, and in particular to a heat dissipation cooling system for a ball screw nut of a machine tool. Background Art

[0002] The ball screw of a machine tool is an important transmission element, which is widely used in various machine tool equipment. With the development of industrial automation and digitalization, the performance and technical requirements of the ball screw of a machine tool are also constantly improving. At present, the ball screw of a machine tool is mainly developing in the direction of high speed, high precision and high rigidity. With the increasing requirements for the processing speed and processing accuracy of machine tools, the speed and accuracy of the ball screw of a machine tool have also been further improved. The use of high-performance materials, precision processing technology and advanced lubrication technology enables the ball screw of a machine tool to achieve higher speed and higher accuracy. However, maintaining the high precision and high speed of the machine tool has become a key issue. As the working time of the machine tool continues to increase, the system heat continues to increase, and the system heat will have a great impact on the processing accuracy of the machine tool. Therefore, in order to ensure the maintenance of the machine tool accuracy, a uniform cooling circulation system is designed for the machine tool.

[0003] At present, forced cooling is generally used to cool the screw or nut. However, this method will cause the temperature of the nut material to change from one extreme hot to another extreme cold. This will shorten the service life of the material, and the overall temperature of the nut cannot be effectively balanced, and thermal deformation of the nut will occur. Therefore, it is necessary to propose a heat dissipation cooling system for ball screw nuts that can achieve continuous and uniform temperature reduction. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a heat dissipation and cooling system for a ball screw nut of a machine tool.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A heat dissipation cooling system for a machine tool ball screw nut is provided, which is used in conjunction with a screw nut to be cooled. The screw nut to be cooled is provided with a plurality of axial heat dissipation channels, including a coolant, a coolant circulation subsystem and a coolant cooling subsystem. The coolant circulation subsystem cooperates with the coolant to cool the screw nut to be cooled, and the coolant cooling subsystem is used to cool the coolant. The coolant circulation subsystem comprises a cooling input pipeline and a cooling output pipeline, one end of the cooling input pipeline is connected to a water tank, and the other end is connected to the inlet of the axial heat dissipation channel; one end of the cooling output pipeline is connected to the water tank, and the other end is connected to the outlet of the axial heat dissipation channel; a hydraulic pump and a flow control valve are provided on the cooling input pipeline; a radiator is provided on the cooling output pipeline, and an S-shaped heat dissipation pipe is provided on the radiator, and the S-shaped heat dissipation pipe is connected to the coolant cooling subsystem.

[0007] Furthermore, a plurality of guide plates are arranged in the radiator, which divide the interior of the radiator into a continuous S-shaped flow cavity. A radiator inlet and a radiator outlet are also arranged on the radiator, and the radiator is installed on the cooling output pipe through the radiator inlet and the radiator outlet.

[0008] Furthermore, the coolant cooling subsystem includes a capillary tube, a filter, a condenser and a compressor, and the S-shaped heat dissipation tube, the capillary tube, the filter, the heat sink and the compressor are connected end to end in sequence through pipelines.

[0009] Furthermore, a pressure relay is provided between the lead screw nut to be cooled and the radiator.

[0010] Furthermore, a hydraulic indicator light is provided between the heat dissipation lead screw nut and the flow control valve.

[0011] Furthermore, an overflow valve is connected between the hydraulic pump and the flow control valve, and an overflow end of the overflow valve is connected to the water tank.

[0012] Furthermore, a one-way valve is arranged in parallel with the flow control valve, and the effective flow direction of the one-way valve is the same as the outflow direction of the flow control valve.

[0013] Furthermore, a heat dissipation fan is included, and the heat dissipation fan is arranged on the outside of the radiator.

[0014] Furthermore, three heat dissipation screw nuts are provided, and the axial heat dissipation channel inlets of the three heat dissipation screw nuts are connected to the cooling input pipeline through a diverter, and the axial heat dissipation channel outlets of the three heat dissipation screw nuts are connected to the cooling output pipeline through a confluence.

[0015] Furthermore, a filter screen is provided at the inlet of the cooling input pipe.

[0016] The beneficial effects of the present invention are:

[0017] Compared with the existing forced cooling method, the present invention can uniformly cool down the nut material to ensure that it is not affected by thermal expansion and contraction. The nut can be kept in a thermal equilibrium state for a long time, thereby improving the transmission accuracy of the ball screw. The ball in the nut may have a local overtemperature due to severe friction, which may cause oxidation or decarburization, causing the ball to lose its luster and generate noise in the nut in the early stage. As the use time increases, the ball surface will fall off or pitting will occur in the later stage, shortening the service life. The forced cooling method will cause the ball surface to change from two extremes, overheating to overcooling, which will shorten the service life of the ball material.

[0018] The present invention cooperates with a coolant cooling subsystem, which ensures the stability of the coolant flow on the one hand, and re-cools the coolant carrying the heat of the nut on the other hand, so that the coolant entering the nut always maintains the rated cooling temperature, thereby repeatedly taking away the excess heat in the nut.

[0019] The present invention cooperates with the axial heat dissipation channel set inside the nut to introduce the coolant into the nut for uniform cooling, which avoids the thermal deformation caused by the nut working for a long time to the greatest extent, and achieves the purpose of high speed and high precision; the liquid circulates in the channel in the nut and exchanges heat with the cooler to obtain the best temperature control quality and accuracy. It is suitable for application in high-speed machine tools and high-speed comprehensive machining centers.

[0020] The present invention designs an axial water channel for the ball screw nut, and passes a forced cooling liquid through the nut to reduce the heat source generation and thermal expansion phenomenon when the ball screw nut is operated at high speed, thereby ensuring high-precision and high-speed operation of the ball screw nut. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the screw nut;

[0023] Figure 3 It is a cross-sectional view of the screw nut;

[0024] Figure 4 It is a schematic diagram of flow diversion;

[0025] Figure 5 Working principle of radiator Figure 1 ;

[0026] Figure 6 Working principle of radiator Figure 2 ;

[0027] Figure 7 It is a working principle diagram of the present invention;

[0028] Figure 8 This is the heat flow change process diagram of the cooling nut;

[0029] Fig. 9 This is the heat flow change process of an ordinary nut;

[0030] Fig.10 This is the steady-state heat flow movement change diagram of an ordinary nut;

[0031] Fig.11 This is the steady-state heat flow movement change diagram of the liquid-cooled nut;

[0032] Fig.12This is the axial temperature diagram of a normal nut in steady state;

[0033] Fig.13 This is the axial temperature diagram of the liquid-cooled nut in steady state;

[0034] Fig.14 It is the principle of temperature movement direction of steady-state ordinary nut and liquid-cooled nut;

[0035] Fig.15 The front view of the ordinary nut and the liquid-cooled nut under working conditions;

[0036] Fig.16 This is the radial temperature distribution diagram of a common nut;

[0037] Fig.17 This is the radial temperature distribution diagram of the liquid-cooled nut;

[0038] Fig.18 This is a comparison chart of the cooling of ordinary nuts and liquid-cooled nuts;

[0039] Fig.19 Comparison of temperature rise between THK nut and liquid-cooled nut;

[0040] Fig. 20 Comparison of thermal stability between THK nuts and liquid-cooled nuts;

[0041] Fig.21 This is the thermal expansion diagram of a common nut;

[0042] Fig. 22 This is the thermal expansion diagram of the liquid-cooled nut;

[0043] The main components in the figure are described as follows:

[0044] 1. Coolant; 2. Filter; 3. Hydraulic pump; 4. Motor; 5. Overflow valve; 6. Check valve; 7. Flow control valve; 8. Hydraulic indicator light; 9. Diverter; 10. X-axis screw; 11. Y-axis screw; 12. Z-axis screw; 13. X-axis nut heat dissipation inlet; 14. X-axis nut heat dissipation outlet; 15. Y-axis nut heat dissipation inlet; 16. Y-axis nut heat dissipation outlet; 17. Z-axis nut heat dissipation inlet; 18. Z-axis nut heat dissipation outlet; 19. Converger; 20. Pressure relay; 21. Radiator inlet; 22. Guide plate; 23. Radiator; 24. Cooling system inlet; 25. Capillary; 26. Filter; 27. Condenser; 28. Cooling system outlet; 29. ​​Radiator outlet; 30. Cooling fan; 31. Compressor inlet; 32. Compressor outlet; 33. Compressor; 34. Coolant tank; 35. Cooling input pipeline; 36. Cooling output pipeline. DETAILED DESCRIPTION

[0045] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0046] like Figure 1 , 2 As shown in Figure 3, the heat dissipation cooling system of the ball screw nut of the machine tool is used in conjunction with the screw nut to be cooled. The screw nut to be cooled is provided with a plurality of axial heat dissipation channels, which include axial channels and radial channels. The axial channels are connected with the radial channels to form an axial heat dissipation channel. The screw nut to be cooled adopts 3D printing technology, and an axial heat dissipation channel can be quickly formed inside the screw nut to be cooled. The ball screw nut and its heat dissipation cooling system include a coolant 1, a coolant circulation subsystem and a coolant cooling subsystem. The coolant circulation subsystem cooperates with the coolant 1 to cool the screw nut to be cooled, and the coolant cooling subsystem is used to cool the coolant 1. The coolant circulation subsystem includes a cooling input pipeline 35 and a cooling output pipeline 36. One end of the cooling input pipeline 35 is connected to the water tank 34, and the other end is connected to the inlet of the axial heat dissipation channel. One end of the cooling output pipeline 36 is connected to the water tank 34, and the other end is connected to the outlet of the axial heat dissipation channel. A hydraulic pump 3 and a flow control valve 7 are provided on the cooling input pipeline 35. The cooling output pipeline 36 is provided with a radiator 23 , and the radiator 23 is provided with an S-shaped heat dissipation pipe, and the S-shaped heat dissipation pipe is connected to the cooling liquid temperature reduction subsystem.

[0047] like Figure 5 and 6 As shown, a plurality of guide plates 22 are arranged in the radiator 23, and the plurality of guide plates 22 divide the interior of the radiator 23 into a continuous S-shaped flow cavity. A radiator inlet 21 and a radiator outlet 29 are also arranged on the radiator 23. The radiator 23 is installed on the cooling output pipe 36 through the radiator inlet 21 and the radiator outlet 29, and the radiator inlet 21 and the radiator outlet 29 are staggered.

[0048] The coolant cooling subsystem includes a capillary 25, a filter 26, a condenser 27 and a compressor 33. The S-shaped heat pipe, the capillary 25, the filter 26, the heat sink 27 and the compressor 33 are connected end to end through pipes in sequence. The coolant cooling subsystem is filled with Freon, such as R22 and R134a, which can cooperate with the coolant cooling subsystem to cool the coolant. The capillary 25 can also be replaced with a more effective expansion valve to make the use of Freon more efficient. When Freon passes through the capillary 25 in the coolant cooling subsystem, the temperature of the S-shaped heat pipe at the outlet end of the capillary 25 gradually decreases, so that the S-shaped heat pipe is used to dissipate heat for the coolant 1 in the radiator 23, thereby ensuring that the coolant 1 efficiently dissipates heat to the screw nut to be cooled. The Freon flows out through the compressor 33, and the matched condenser 27 discharges the heat, and finally returns to the capillary 25 through the filter 26, realizing a cyclic refrigeration operation, and continuously dissipating the heat and cooling the coolant 1 passing through the radiator 23, which ensures the efficient heat dissipation of the lead screw nut to be cooled during operation, and is conducive to ensuring the movement accuracy of the lead screw nut to be cooled during operation.

[0049] In this embodiment, a hydraulic indicator light 8 is provided between the lead screw nut to be cooled and the flow control valve 7, and the hydraulic indicator light 8 is used to indicate whether the coolant circulation subsystem is working normally.

[0050] In this embodiment, an overflow valve 5 is connected between the hydraulic pump 3 and the flow control valve 7, and the overflow end of the overflow valve 5 is connected to the water tank 34. The overflow valve 5 allows the excess flow to overflow back to the coolant tank 34, thereby maintaining the outlet pressure of the hydraulic pump 3 constant.

[0051] In this embodiment, the flow control valve 7 is provided in parallel with a check valve 6, and the effective flow direction of the check valve 6 is the same as the outflow direction of the flow control valve 7. The check valve 6 can effectively prevent the coolant 1 from flowing back in the coolant circulation subsystem.

[0052] In this embodiment, a heat dissipation fan 30 is further included. The heat dissipation fan 30 is disposed outside the radiator 23 . The heat dissipation fan 30 can better dissipate heat from the radiator 23 .

[0053] In this embodiment, a pressure relay 20 is provided between the lead screw nut to be cooled and the radiator 23. The pressure relay 20 can detect the water pressure of the coolant flowing out of the lead screw nut to be cooled, so as to facilitate the adjustment of the hydraulic pump 3 to control the water pressure of the coolant. The hydraulic pump 3 is driven by the motor 4 to adjust the speed of the motor 4, thereby realizing the adjustment and control of the pressure of the hydraulic pump 3.

[0054] In this embodiment, a filter screen 2 is provided at the inlet of the cooling input pipe 35. The filter screen 2 can effectively intercept impurities entering the cooling input pipe 35, prevent the impurities from entering the axial heat dissipation channel of the lead screw nut to be cooled, block the axial heat dissipation channel, and affect the cooling and heat dissipation of the lead screw nut to be cooled.

[0055] In this embodiment, the outlet end of the capillary tube 25 is connected to the inlet end of the S-shaped heat pipe, the inlet end of the capillary tube 25 is connected to the outlet end of the filter 26, the inlet end of the filter 26 is connected to the outlet end of the condenser 27, and the compressor 33 is connected to the outlet end of the S-shaped heat pipe through the compressor inlet 31, and is connected to the inlet end of the condenser 27 through the compressor outlet 32.

[0056] In this embodiment, there are three places where the heat dissipation screw nut is provided, and the axial heat dissipation channel entrances of the three heat dissipation screw nuts are connected to the cooling input pipe 35 through the diverter 9, and the axial heat dissipation channel exits of the three heat dissipation screw nuts are connected to the cooling output pipe 36 through the confluence 19. Cooling and dissipating the three heat dissipation screw nuts can meet the processing requirements of three-axis machine tools, three-axis printers, etc. The three screw nuts are respectively the X-axis screw 11, the Y-axis screw 12 and the Z-axis screw 13, and the X-axis screw nut is provided with an X-axis nut heat dissipation entrance 13 and an X-axis nut heat dissipation exit 14, the Y-axis screw nut is provided with a Y-axis nut heat dissipation entrance 15 and a Y-axis nut heat dissipation exit 16, and the Z-axis screw nut is provided with a Z-axis nut heat dissipation entrance 17 and a Z-axis nut heat dissipation exit 18. The cooling input pipe is connected to the X-axis nut heat dissipation entrance 13, the Y-axis nut heat dissipation entrance 15 and the Z-axis nut heat dissipation entrance 17 through the diverter 9. The cooling output pipeline is connected to the X-axis nut heat dissipation outlet 14, the Y-axis nut heat dissipation outlet 16 and the Z-axis nut heat dissipation outlet 18 through the concentrator 19. The X-axis lead screw 11, the Y-axis lead screw 12 and the Z-axis lead screw 13. The flow divider 9 and the concentrator 19 both use multi-channel pipe joints. The schematic diagram of the graded flow direction of the lead screw nut to be cooled to the heat dissipation channel is as follows: Figure 4 shown.

[0057] Working process and principle: Figure 7 As shown, blue represents the inflow of coolant 1 into the coolant circulation subsystem, red represents the outflow of coolant 1 from the coolant circulation subsystem, and green represents the cooling process of coolant 1 by Freon in the coolant cooling subsystem.

[0058] like Figure 8As shown in the figure, the coolant does not flow to the tail end of the nut immediately after entering the nut, but pauses in the flange chamber first, and then gradually begins to transition to the tail end of the nut. During this period, the cooling nut begins to exchange heat, so the maximum flow rate of the heat flow is not at the tail end of the nut, but is mainly distributed at the transition position between the flange and the nut body. Since the coolant is buffered in the flange chamber, the potential energy is greatly weakened, and the coolant itself has a certain viscosity, so the heat flow exchange of the cooling nut is relatively slow at the beginning, but when the coolant adapts to the buffer, the heat flow exchange begins to gradually accelerate, and when t=6s, the coolant speed begins to increase significantly.

[0059] like Fig. 9 As shown in the figure, ordinary nuts are not designed with coolant flow channels, so there is a lack of coolant support, the heat capacity of the nuts is very limited, and the equivalent load wrapped on the ordinary nuts seriously hinders the heat exchange of the nuts, so most of the heat of the ordinary nuts cannot be discharged in time. In the same time period, the heat flow reaction inside the ordinary nut is more intense. The maximum speed band of the heat flow is widely distributed, mainly starting around the inner diameter of the nut, which is the main place where the heat source of the nut occurs. And starting from t=6s, the heat flow forms turbulence at the transition position between the flange and the nut body. This shows that the heat flow velocity doubles at this position, and the heat flow changes most dramatically. Many small vortices are formed in the flow field, and the laminar flow is destroyed, resulting in sliding and mixing between adjacent flow layers, and finally forming turbulence. However, no turbulence phenomenon in the heat flow field occurred in the cooling nut experiment. When t=0s~4s, the heat flow diffusion speed of the cooling nut is slow and basically in stratified flow, without mixing, which belongs to steady flow change. When t=4s~10s, the heat flow velocity gradually increases, and the fluid streamlines begin to swing in a wave-like manner. The frequency and amplitude of the swing increase with the increase in flow velocity, and a transitional flow change occurs.

[0060] like Fig.10 As shown in the figure, the situation when the ordinary nut and the liquid-cooled nut reach thermal steady state. The heat flux of the ordinary nut at the heat source position of the raceway changes more violently, and the influence on the surrounding area is gradually developing. This is the reason why the heat flux cannot be eliminated in time. On the one hand, the heat source cannot be suppressed, and on the other hand, the heat flux cannot be eliminated in time, so the following occurs. Fig.10 As shown, the maximum heat flow velocity is basically distributed at the inner diameter of the nut.

[0061] like Fig.11As shown in the figure, the diffusion of heat flow at the cooling nut flange position is suppressed, mainly due to the design of the cooling nut flange chamber, which can store and buffer a part of the coolant, thereby suppressing the further diffusion of friction heat. The heat flow movement of the cooling nut is relatively slow. This is because the cooling nut adopts an annular cooling channel. The channel covers the entire nut heat source and is closer to the heat source. It can effectively suppress the further diffusion of heat flow. The coolant in the channel carries the heat flow out of the nut in time. At the same time, the diffusion of heat flow at the tail of the cooling nut is also relatively suppressed. Since the nut bottom cover also plays the role of coolant buffering, it increases the residence time of the coolant and fully absorbs the heat flow of the nut, so that the coolant is efficiently utilized.

[0062] High-speed ball screw nut temperature rise analysis: Heat flow is a reflection of the nut temperature rise, and the nut temperature rise is a measure of the accumulated heat flow. Therefore, a comprehensive analysis of the nut temperature is to further explore the expansion mechanism of the liquid-cooled nut.

[0063] Analysis of axial temperature rise of high-speed ball screw nuts: Compared with radial temperature, axial temperature change of the nut will more comprehensively reflect the temperature distribution of the nut, thus providing a certain degree of pertinence for the formulation of nut cooling strategies. The nut works under load conditions, and it is more objective to observe the temperature distribution of the nut and make an evaluation. Ignoring the load conditions and simply evaluating the temperature rise of the nut is one-sided, as the load conditions and installation methods will seriously affect the heat dissipation of the nut surface.

[0064] The temperature rise test parameters are shown in Table 1. The axial temperature zone distribution of the nut after it forms a steady state under load conditions is as follows: Fig.12 and 13 As shown. For ordinary nuts, there is a lack of liquid cooling. The heat on the nut surface is difficult to dissipate in time due to the heat wrapped by the load, so most of the temperature is concentrated on the nut surface. After the temperature of the nut surface is saturated, the temperature begins to expand to the two end faces. At this time, the nut flange and the tail end become the heat exchange ends with the air, and are also the main channels for the nut to dissipate heat. Due to the sheet structure, the flange not only plays a connecting role, but also serves as a heat sink, so the temperature rise is second only to the nut body and presents a very high trend. Therefore, the temperature will begin to develop towards both ends of the nut.

[0065] The axial temperature change of the liquid-cooled nut is relatively uniform, mainly due to the design of the annular cooling channel. The coolant evenly covers the entire nut, effectively suppressing the heat source of the nut in a timely manner. The temperature diffusion does not gather, and the distribution is relatively uniform.

[0066] Although both use the same nut drive, their cooling methods are completely different. The heat dissipation principle of ordinary nuts is essentially to exchange heat with the air, which is air cooling. The heat dissipation principle of liquid-cooled nuts is to exchange heat with liquid, which is liquid cooling. Fig.14As shown in the figure, the expansion modes of the two nuts change. The temperature diffusion of the liquid-cooled nut mainly develops radially, while the temperature diffusion of the ordinary nut develops axially. This is because the nut load limits the heat dissipation of the nut into the air, causing the two end faces of the nut to become the main heat dissipation surfaces for air convection, thus inducing the heat of the ordinary nut to continue to develop towards both ends. However, due to the presence of coolant flow channels throughout the liquid-cooled nut, the heat of the nut will be gradually reduced along the axial direction and integrated into the coolant until it is carried out of the nut and induced to develop in the radial direction of the nut.

[0067]

[0068] Table 1 Basic parameters of temperature field

[0069] High-speed ball screw nut radial temperature analysis: The radial temperature of the nut is to explore the distribution of the nut temperature gradient. Through radial temperature analysis, we can understand the temperature changes in space and find possible temperature gradients. The second is to evaluate the thermal conductivity of the nut, so as to understand the heat transfer characteristics of the special structure of the nut.

[0070] like Fig.15 As shown in the figure, the radial temperature distribution of ordinary nuts and liquid-cooled nuts changes. The surface temperature of ordinary nuts is higher than the internal temperature. This is because the heat exchange between the nut surface and the outside world is closer, which accelerates the heat to approach the heat exchange surface. The liquid-cooled nut is centered on the annular water channel, and the heat of the nut uniformly shrinks toward the annular water channel. Compared with ordinary nuts, liquid-cooled nuts change the heat trend. The inner surface of the nut exchanges heat with the annular water channel. On the one hand, the annular water channel increases the heat exchange area compared to ordinary nuts. On the other hand, the coolant has a larger specific heat capacity, so it can carry more heat per unit time.

[0071] like Fig.16 As shown in the figure, there is a gradient in the radial temperature of ordinary nuts, and there is a significant difference in the temperature between the surface and the inside of ordinary nuts. Fig.17 As shown in the figure, the radial temperature gradient of the liquid-cooled nut becomes larger, indicating that the temperature transition occurs near the water channel. At the annular water channel of the liquid-cooled nut, the temperature completes the heat exchange movement, so the temperature here is higher. Under the condition of ensuring the coolant flow, as time increases, the liquid-cooled nut is easier to reach a stable state than the ordinary nut. Therefore, the change trend of each cross section of the liquid-cooled nut is relatively slow.

[0072] like Fig.18 As shown in the figure, compared with the ordinary nut air cooling, the liquid cooling nut has a more obvious cooling effect, with an average temperature reduction of 41.2%. Fig.19As shown in the figure, as the working time of the nut increases, the thermal stability of the liquid-cooled nut is higher than that of the THK. This is because the THK cooling water channel is too narrow and cannot fully cover the nut, so the initial temperature rise of the nut is enough to suppress the heat source and the thermal stability is good. However, after 50 minutes, the thermal stability of the nut fluctuated significantly, indicating that the cooling water channel is no longer sufficient to cope with the heat generated by the nut. The liquid-cooled nut annular water channel has a large expansion area and wide coverage, so it can fully suppress the temperature rise of the nut and has good thermal stability. Fig. 20 As shown, the liquid-cooled nut is not superior to the THK liquid-cooled nut in temperature reduction performance, but in excellent thermal stability. The thermal stability is improved by an average of 48.1% compared to the THK liquid-cooled nut. Fig.21 , 22 As shown in the figure, the expansion form of the ordinary nut is convex and mushroom-shaped. The liquid-cooled nut is concave and Y-shaped. Compared with the ordinary nut, the axial expansion is reduced by 60.5% and the radial expansion is reduced by 71.9%.

[0073] In summary: The present invention has designed a cooling water channel structure for the liquid-cooled nut, and conducted a temperature change simulation experiment. The nut heat flow change law and temperature distribution are analyzed, and the following beneficial effects are obtained: 1. The nut heat flow is a reflection of the nut temperature rise, and the nut temperature rise is the cause of the nut expansion. The progressive development of the three constitutes the nut thermal deformation mechanism. 2. Compared with ordinary nuts, the working temperature of liquid-cooled nuts is reduced by an average of 41.2%; compared with THK liquid-cooled nuts, the thermal stability is improved by 48.1%. 3. For the evaluation of nut cooling performance, cooling is not the most powerful evaluation indicator. The evaluation indicators from low to high are cooling performance, thermal uniformity retention, and thermal stability retention.

Claims

1. A heat dissipation cooling system for a ball screw nut of a machine tool, used in conjunction with a ball screw nut to be cooled, wherein the ball screw nut to be cooled is provided with a plurality of axial heat dissipation channels, and characterized in that: It comprises a coolant (1), a coolant circulation subsystem and a coolant cooling subsystem, wherein the coolant circulation subsystem cooperates with the coolant (1) to cool the lead screw nut to be cooled, and the coolant cooling subsystem is used to cool the coolant (1); The cooling liquid circulation subsystem comprises a cooling input pipe (35) and a cooling output pipe (36); one end of the cooling input pipe (35) is connected to the water tank (34), and the other end is connected to the inlet of the axial heat dissipation channel; one end of the cooling output pipe (36) is connected to the water tank (34), and the other end is connected to the outlet of the axial heat dissipation channel; The cooling input pipeline (35) is provided with a hydraulic pump (3) and a flow control valve (7); the cooling output pipeline (36) is provided with a radiator (23), the radiator (23) is provided with an S-shaped heat dissipation pipe, and the S-shaped heat dissipation pipe is connected to the cooling liquid temperature reduction subsystem.

2. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 2, characterized in that: The radiator (23) is provided with a plurality of guide plates (22), and the plurality of guide plates (22) divide the interior of the radiator (23) into a continuous S-shaped flow cavity. The radiator (23) is also provided with a radiator inlet (21) and a radiator outlet (29). The radiator (23) is installed on the cooling output pipe (36) through the radiator inlet (21) and the radiator outlet (29).

3. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: The cooling liquid cooling subsystem comprises a capillary tube (25), a filter (26), a condenser (27) and a compressor (33); the S-shaped heat dissipation tube, the capillary tube (25), the filter (26), the heat sink (27) and the compressor (33) are connected end to end in sequence through pipelines.

4. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: A pressure relay (20) is provided between the lead screw nut to be cooled and the radiator (23).

5. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: A hydraulic indicator light (8) is provided between the lead screw nut to be cooled and the flow control valve (7).

6. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: An overflow valve (5) is connected between the hydraulic pump (3) and the flow control valve (7), and an overflow end of the overflow valve (5) is connected to a water tank (34).

7. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: The flow control valve (7) is provided with a one-way valve (6) in parallel, and the effective flow direction of the one-way valve (6) is the same as the outflow direction of the flow control valve (7).

8. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: A heat dissipation fan (30) is also included, and the heat dissipation fan (30) is arranged outside the radiator (23).

9. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: The screw nut to be cooled is provided at three locations, and the axial heat dissipation channel inlets of the three screw nuts to be cooled are connected to the cooling input pipeline (35) through a diverter (9), and the axial heat dissipation channel outlets of the three screw nuts to be cooled are connected to the cooling output pipeline (36) through a confluence (19).

10. The heat dissipation and cooling system for a machine tool ball screw nut according to claim 1, characterized in that: A filter screen (2) is provided at the inlet of the cooling input pipe (35).

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