Flexible adjustable mixed line machine tool spindle cooling system and method

Abstract

The invention provides a flexible adjustable mixed line machine tool spindle cooling system and method, and belongs to the technical field of machine manufacturing. The system comprises a main shaft cooling unit, a dry type air cooling unit, a circulating cooling water unit and a cutting fluid cooling unit, integrates four cooling modes of traditional cutting fluid, minimal quantity lubrication, dry type air cooling and circulating water cooling, and is provided with temperature, flow, cutting force and liquid level monitoring instruments as well as a regulating valve, a switching valve, power equipment and the like which are correspondingly interlocked. By monitoring machine tool machining states such as spindle temperature and cutting force in real time and dynamically optimizing a cooling strategy, flexible switching among four modes and parameter regulation and control are achieved, so that machining heat damage is reduced, the service life of a tool is prolonged, the machining efficiency is improved, meanwhile, cooling medium consumption is reduced, and the efficient, low-cost, low-carbon and safe machining process is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical manufacturing, and in particular relates to a flexible and adjustable mixed-line machine tool spindle cooling system and method. Background Art

[0002] In today's aviation manufacturing sector, aircraft structural parts are produced in a variety of varieties and small batches. This requires machining shops to adopt a flexible mixed-line production model, where the same machine tool alternates between processing different materials, such as aluminum alloy and titanium alloy. However, the machining characteristics of these two materials differ significantly: aluminum alloy has good thermal conductivity, allowing for high-speed cutting, but the chips tend to stick to the tool; titanium alloy has poor thermal conductivity (only 1 / 16 of that of aluminum alloy), which easily generates high temperatures during cutting, leading to rapid tool wear and thermal deformation of the spindle. This mixed-line processing requirement poses a severe challenge to the machine tool cooling system—it must adapt to the cooling requirements of different materials while maintaining stable machining accuracy even when frequently switching between machining objects.

[0003] Currently, mainstream cooling methods include traditional cutting fluid cooling, minimal quantity lubrication (MQL), and dry air cooling, all of which have significant shortcomings when dealing with mixed-line machining. While traditional cutting fluid cooling is suitable for titanium alloy machining and effectively reduces temperatures, it can lead to overcooling when applied to aluminum alloys. This not only increases energy consumption (cooling system power consumption can account for 20% of the machine tool's total power consumption) but can also degrade the surface quality of aluminum alloy workpieces. Extensive use not only increases machining costs (accounting for approximately 15-20% of total machining costs) but also creates challenges with waste fluid disposal, which is inconsistent with the trend of green manufacturing. Furthermore, cutting fluid penetration can contaminate spindle bearings, reducing their service life. Minimum quantity lubrication (MQL) performs well under moderate cutting parameters, such as in aluminum alloy machining. However, its cooling capacity is insufficient for high-efficiency machining of titanium alloys (e.g., cutting speeds exceeding 100 m / min). Furthermore, current systems struggle to optimize the oil-air mixture ratio and injection parameters in real time based on machining conditions, resulting in unstable cooling. Although dry air cooling is environmentally friendly, its cooling efficiency is low and it is difficult to meet the high heat dissipation requirements of titanium alloy processing. It also lacks precise control of air flow temperature and flow, which affects chip discharge and processing quality.

[0004] Most existing cooling systems use fixed modes and cannot be adaptively adjusted according to the processing material, tool status and cutting parameters, resulting in low cooling efficiency or waste of resources, which has proven to affect the efficiency of mixed-line production. At present, the spindle cooling solutions of existing patents and machine tools only support a single cooling mode, and the hybrid cooling system lacks a dynamic collaborative control mechanism when switching modes, which easily causes fluctuations in the processing process. Therefore, it is urgent to develop an intelligent and adjustable cooling system that can flexibly switch between four modes: traditional cutting fluid, minimal lubrication, dry air cooling and circulating water cooling according to processing requirements, and dynamically optimize the cooling strategy by real-time monitoring of parameters such as spindle temperature and cutting force to reduce processing thermal damage, extend tool life and improve processing efficiency, while reducing cooling medium consumption. This is of great significance to the flexibility and intelligence of aviation manufacturing. Summary of the Invention

[0005] In order to solve the applicability problem caused by the single cooling mode and fixed parameters of traditional machine tool spindles, a flexible and adjustable mixed-line machine tool spindle cooling system and method are proposed. The cooling mode and parameters can be flexibly switched according to processing requirements and real-time status, thereby realizing an efficient, low-cost, low-carbon and safe machining process.

[0006] In the first aspect, the present invention provides a flexible and adjustable mixed-line machine tool spindle cooling system, the cooling system comprising a spindle cooling unit, a dry air cooling unit, a circulating cooling water unit and a cutting fluid cooling unit; The spindle cooling unit is composed of a spindle cooling medium inlet, a spindle, a spindle spiral fin, a spindle protection shell, a spindle cooling medium outlet, a machining tool and a tool cooling nozzle; The spindle, the spindle spiral fins, the spindle protective housing, and the spindle cooling medium outlet are connected in sequence from the inside to the outside, the spindle cooling medium inlet is connected to the spindle spiral fin inlet through the spindle protective housing, the spindle cooling medium outlet is connected to the spindle spiral fin outlet through the spindle protective housing, the machining tool is connected to the lower end of the spindle, and N tool cooling nozzles are located outside the machining tool; N is an even number greater than 2; The dry air cooling unit consists of a cold air blower, a cold air source, a cold air regulating valve V1, an exhaust valve V3 and N cold air nozzle switch valves; Among them, the cold air blower inlet is connected to the cold air source outlet, the cold air blower outlet is connected to the cold air regulating valve V1 inlet, the cold air regulating valve V1 outlet is connected to the spindle cooling medium inlet, the exhaust valve V3 inlet is connected to the spindle cooling medium outlet, and the exhaust valve V3 outlet is connected to the exhaust pipe; the N cold air nozzle switch valve inlets are all connected to the cold air blower outlet, and the N cold air nozzle switch valve outlets are respectively connected to the N tool cooling nozzle inlets; The circulating cooling water unit consists of a cooling water storage tank, a cooling water supply pump, a condenser, a circulating cooling water inlet, a circulating cooling water outlet, a cooling water regulating valve V2 and a condensing regulating valve V4; Among them, the cooling water supply pump inlet is connected to the cooling water storage tank outlet, the cooling water supply pump outlet is connected to the cooling water regulating valve V2 inlet, the cooling water regulating valve V2 outlet is connected to the spindle cooling medium inlet, the spindle cooling medium outlet is connected to the condensation regulating valve V4 inlet, the condensation regulating valve V4 outlet is connected to the circulating cooling water inlet, the condenser inlet is connected to the circulating cooling water inlet, the condenser outlet is connected to the circulating cooling water outlet, and the circulating cooling water outlet is connected to the cooling water regulating valve V2 inlet; The cutting fluid cooling unit is composed of a cutting fluid storage tank, a cutting fluid recovery device, a cutting waste fluid delivery pump, a cutting fluid supply pump, a cutting waste fluid storage tank, N cutting fluid nozzle regulating valves and a cutting waste fluid regulating valve V13; Among them, the outlet of the cutting fluid storage tank is connected to the inlet of the cutting fluid supply pump, the outlets of the cutting fluid supply pump are all connected to the inlets of N cutting fluid nozzle regulating valves, the outlets of the N cutting fluid nozzle regulating valves are respectively connected to the inlets of N tool cooling nozzles, the inlet of the cutting waste fluid storage tank is connected to the outlet of the tool cooling nozzle, the outlet of the cutting waste fluid storage tank is respectively connected to the cutting waste fluid delivery pump and the cutting fluid supply pump, the outlet of the cutting waste fluid delivery pump is connected to the inlet of the cutting fluid recovery device, and the outlet of the cutting fluid recovery device is connected to the inlet of the cutting fluid storage tank.

[0007] Furthermore, the system also includes: 3 flow meters, 2 temperature meters, 3 liquid level meters, and a cutting force monitoring instrument C, wherein the 3 flow meters are respectively located at the outlets of the cooling water supply pump, the cold air blower, and the cutting fluid supply pump; Two temperature instruments are located between the spindle and the spindle spiral fins and at the circulating cooling water outlet; the cutting force monitoring instrument C is loaded on the spindle; and the three liquid level instruments are located at the cooling water storage tank, the cutting waste liquid storage tank and the side wall of the cutting fluid storage tank.

[0008] Furthermore, the cooling water supply pump, cold air blower, and cutting fluid supply pump are all frequency conversion devices, which are interlocked with three flow meters respectively, and are all interlocked with the cutting force monitoring instrument C; the cooling water supply pump is interlocked with the cooling water regulating valve V2 and the condensation regulating valve V4; the cold air blower is interlocked with the cold air regulating valve V1, the exhaust valve V3, and N cold air nozzle switch valves; the cutting fluid supply pump is interlocked with N cutting fluid nozzle regulating valves; the temperature instrument T1 is interlocked with the cooling water supply pump, the cooling water regulating valve V2, the cold air blower, and the cold air regulating valve V1; the temperature instrument T2 is interlocked with the condenser power; and the two liquid level instruments are interlocked with the cutting waste liquid delivery pump and the cutting waste liquid regulating valve V13.

[0009] Furthermore, the spindle, spindle spiral fins, spindle protective shell, and spindle cooling medium outlet are coaxially combined from the inside to the outside, wherein the spindle spiral fins are fastened to the inner wall of the spindle protective shell, and the connection form is welding, riveting or screwing; the spindle spiral fins and the spindle protective shell are fastened to the spindle as a whole and sealed to form a hollow space; the temperature instrument T1 measuring point is placed at the bottom of this hollow space, and the lead direction and the header position are determined according to the machine tool space.

[0010] Furthermore, the shaft cooling medium inlet is located at the upper end of the main shaft protective shell, and is connected to the spiral flow channel that passes through the main shaft protective shell and is connected to the main shaft spiral fin; the main shaft cooling medium outlet is located at the bottom end of the main shaft protective shell, and is connected to the spiral flow channel that passes through the main shaft protective shell and is connected to the main shaft spiral fin.

[0011] Furthermore, the tool cooling nozzle adopts a dual-channel design, with the cold air channel located inside and the cutting fluid channel located outside, and the cold air channel and the cutting fluid channel are coaxial.

[0012] Furthermore, the N tool cooling nozzles are distributed at equal distances and angles on the upper end of the machining tool with the machining tool as the center of the circle, and the nozzle axis is collinear with the normal of the machining tool; the tool cooling nozzle inlet has two branches, which are respectively connected to the N cold air nozzle switch valves and the N cutting fluid nozzle regulating valves.

[0013] Furthermore, the cutting waste liquid storage tank is integrated at the bottom of the machine tool and is connected to the cutting fluid at the outlet of the tool cooling nozzle; the inlet of the cutting waste liquid delivery pump is located at the bottom of the cutting waste liquid storage tank, and a discharge port is provided at the top of the cutting waste liquid storage tank.

[0014] Furthermore, the circulating cooling water inlet and circulating cooling water outlet are respectively located at the lower end and upper end of the condenser; the cooling water supply pump inlet is located at the bottom of the cooling water storage tank, the cutting fluid supply pump inlet is located at the bottom of the cutting fluid storage tank, and the cutting fluid recovery device outlet is located at the top of the cutting fluid storage tank.

[0015] In a second aspect, the present invention further provides a flexible and adjustable mixed-line machine tool spindle cooling method, which is applied to the system and includes the following steps: 1) The system uses a dry air cooling unit by default to cool the machine tool spindle. Cold air from the cold air source flows through the cold air blower, cold air control valve V1, and the spindle cooling medium inlet, entering the spiral flow channel between the spindle protection housing and the spindle spiral fins to cool the spindle. It then flows out of the spindle cooling medium outlet and is exhausted through the exhaust valve V3. Other valves remain normally closed, and the power unit remains in the shutdown state. According to the display of temperature instrument T1, if the spindle temperature fluctuates within the designed upper and lower limits, the cold air blower frequency and the opening of the cold air control valve V1 are adjusted through interlocking feedback. 2) According to the display of temperature instrument T1, if the spindle temperature exceeds the design upper limit of the air cooling mode, the circulating cooling water unit is switched to cool the machine tool spindle. The cold air regulating valve V1 and exhaust valve V3 are closed, and the cooling water regulating valve V2, condensation regulating valve V4, and condenser are opened. The cooling water from the cooling water storage tank passes through the cooling water supply pump, cooling water regulating valve V2, and spindle cooling medium inlet in sequence and enters the spiral flow channel of the spindle protection shell and the spindle spiral fins to cool the spindle. It then flows out from the spindle cooling medium outlet, passes through the condensation regulating valve V4 and the condenser to condense into circulating cooling water, and then enters the spindle cooling unit through the cooling water regulating valve V2 again. After the circulation is stable, the cooling water supply pump automatically shuts down. According to the display of temperature instrument T1, the spindle temperature is adjusted through interlocking feedback to adjust the cooling water supply pump frequency and the opening of the cooling water regulating valve V2. 3) The system uses a dry air cooling unit by default for machining tool cooling. Cold air from the cold air source is sequentially ejected through the cold air blower, N cold air nozzle switch valves, and the tool cooling nozzles to cool the tool. Other valves remain normally closed, and the power unit remains in a shutdown state. According to the display of the cutting force monitoring instrument C, if the cutting force fluctuates within the upper and lower limits of the air cooling mode design, the frequency of the cold air blower and the opening and closing of the N cold air nozzle switch valves are adjusted through interlocking feedback. 4) According to the display of the cutting force monitoring instrument C, if the tool cutting force exceeds the design upper limit of the air cooling mode, the cutting fluid cooling unit is started, and the mode is switched to the minimal lubrication mode. The N cold air nozzle switch valves are kept open, and the N cutting fluid nozzle regulating valves, cutting fluid supply pump, and cutting waste fluid delivery pump are started; the cutting fluid from the cutting fluid storage tank is sprayed out through the cutting fluid supply pump, N cutting fluid nozzle regulating valves, and tool cooling nozzle to cool the tool; the flowing cutting fluid is collected in the cutting waste fluid storage tank at the bottom of the machine tool, enters the cutting fluid recovery device through the cutting waste fluid delivery pump, and re-enters the cutting fluid storage tank for recycling after treatment; if the cutting force fluctuates within the design upper and lower limits of the minimal lubrication mode, the frequency of the cutting fluid supply pump and the opening of the N cutting fluid nozzle regulating valves are adjusted through interlocking feedback; if the cutting force exceeds the design upper limit of the minimal lubrication mode, the cold air blower and the N cold air nozzle switch valves are shut down in sequence, and as the cutting force changes, the frequency of the cutting fluid supply pump and the opening of the N cutting fluid nozzle regulating valves are adjusted through interlocking feedback; 5) According to the display of temperature instrument T2, the circulating cooling water temperature adjusts the condenser power through interlock feedback; 6) According to the display of the two liquid level instruments, the liquid levels of the cutting waste liquid storage tank and the cutting fluid storage tank are adjusted through interlocking feedback to adjust the start and stop and frequency of the cutting waste liquid delivery pump and the opening of the cutting waste liquid regulating valve V13.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The flexible and adjustable mixed-line machine tool spindle cooling system and method disclosed in the present invention innovatively integrates four cooling modes: traditional cutting fluid, minimal lubrication, dry air cooling, and circulating water cooling. It is equipped with temperature, flow, cutting force, and liquid level monitoring instruments, as well as corresponding interlocking regulating valves, switch valves, power equipment, etc., to form a flexible and adjustable mixed-line machine tool spindle cooling system. Based on the processing method of the above system, it innovatively proposes to dynamically optimize the cooling strategy by real-time monitoring of parameters such as spindle temperature and cutting force, thereby achieving flexible switching and parameter control between the four modes. Compared with the existing technology, this patent can enable mechanical processing to be carried out in a cooling mode and working condition that is more suitable for the processing state and working conditions, that is, it avoids damage to the machine tool caused by spindle overheating, rapid wear and workpiece damage caused by tool overheating, reduces processing heat damage, extends tool life, and improves processing efficiency, and avoids excessive consumption of cooling medium, increased carbon emissions, and environmental pollution caused by the over-protection cooling mode of mixed-line processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a flexible and adjustable mixed-line machine tool spindle cooling system; Among them, 1 is the spindle cooling medium inlet, 2 is the spindle, 3 is the spindle spiral fin, 4 is the spindle protective shell, 5 is the spindle cooling medium outlet, 6 is the circulating cooling water inlet, 7 is the condenser, 8 is the circulating cooling water outlet, 9 is the cutting fluid storage tank, 10 is the cutting fluid recovery device, 11 is the cutting waste liquid delivery pump, 12 is the cutting fluid supply pump, 13 is the cutting waste liquid storage tank, 14 is the machining tool, 15 is the tool cooling nozzle, 16 is the cold air blower, 17 is the cold air source, 18 is the cooling water supply pump, 19 is the cooling water storage tank, V1 is the cold air regulating valve, V2 is the cooling water regulating valve, V3 is the exhaust valve, V4 is the condensation regulating valve, V5-V8 is the cold air nozzle switch valve, V9-V12 is the cutting fluid nozzle regulating valve, and V13 is the cutting waste liquid regulating valve. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain the present invention rather than to limit it.

[0019] See also Figure 1 The present invention provides a flexible and adjustable mixed-line machine tool spindle cooling system, which includes a spindle cooling unit, a dry air cooling unit, a circulating cooling water unit and a cutting fluid cooling unit.

[0020] (1) The spindle cooling unit consists of a spindle cooling medium inlet 1, a spindle 2, a spindle spiral fin 3, a spindle protective housing 4, a spindle cooling medium outlet 5, a machining tool 14, and a tool cooling nozzle 15. The cooling medium from the dry air cooling unit and the circulating cooling water unit sequentially enters the spindle cooling medium inlet 1, the spiral cooling channel consisting of the spindle 2, the spindle spiral fin 3, and the spindle protective housing 4, and the spindle cooling medium outlet 5 to complete the cooling process of the spindle; the cooling medium from the dry air cooling unit, the circulating cooling water unit, and the cutting fluid cooling unit enters the tool cooling nozzle 15 to complete the cooling process of the machining tool.

[0021] (2) The dry air cooling unit consists of a cold air blower 16, a cold air source 17, a cold air regulating valve V1, an exhaust valve V3, and cold air nozzle switch valves V5-V8. In the air cooling mode, cold air from the cold air source 17 enters the spindle unit through the cold air blower 16, the cold air regulating valve V1, and the spindle cooling medium inlet 1, cooling the spindle 2. The air is then exhausted through the exhaust valve and cools the machining tool 14.

[0022] (3) The circulating cooling water unit consists of a cooling water storage tank 19, a cooling water supply pump 18, a condenser 7, a circulating cooling water inlet 6, a circulating cooling water outlet 8, a cooling water regulating valve V2, and a condensation regulating valve V4. In the water cooling mode, the cooling water from the cooling water storage tank 19 flows through the cooling water supply pump 18 and the cooling water regulating valve V2 in sequence, enters the spindle unit to cool the spindle 2, and then passes through the condensation regulating valve V4 and the condenser 7 to form circulating cooling water. The water then flows back through the cooling water regulating valve V2 and enters the cooling system. After the circulation stabilizes, the cooling water supply pump 18 automatically shuts down.

[0023] (4) The cutting fluid cooling unit is composed of a cutting fluid storage tank 9, a cutting fluid recovery device 10, a cutting fluid waste pump 11, a cutting fluid supply pump 12, a cutting fluid storage tank 13, cutting fluid nozzle regulating valves V9-V12, and a cutting fluid waste regulating valve V13. In the cutting fluid cooling mode, the cutting fluid from the cutting fluid storage tank 9 passes through the cutting fluid supply pump 12 and the cutting fluid nozzle regulating valves V9-V12, enters the tool cooling nozzle 15, and is sprayed out to cool the tool; the flowing cutting fluid is collected in the cutting fluid storage tank 13 at the bottom of the machine tool, enters the cutting fluid recovery device 10 through the cutting fluid supply pump 11, and re-enters the cutting fluid storage tank 9 for recycling after treatment.

[0024] (5) During the cooling process of spindle 2, the system uses a dry air cooling unit by default to cool the machine tool spindle, monitors the temperature instrument T1, and adjusts the cooling mode and parameters according to the reading. If the spindle temperature fluctuates within the design upper and lower limits, the frequency of the cold air blower 16 and the opening of the cold air regulating valve V1 are adjusted through interlocking feedback; if the spindle temperature exceeds the design upper limit of the air cooling mode, the circulating cooling water unit is switched to cool the machine tool spindle, the cold air regulating valve V1 and the exhaust valve V3 are closed, the cooling water regulating valve V2, the condensation regulating valve V4, and the condenser 7 are opened, and the spindle temperature is controlled by adjusting the frequency of the cooling water supply pump 18 and the opening of the cooling water regulating valve V2.

[0025] (6) During the cooling process of the machining tool 14, the system uses the dry air cooling unit by default to cool the machining tool 14, monitors the cutting force monitoring instrument C, and adjusts the cooling mode and parameters according to the readings. If the cutting force fluctuates within the upper and lower limits of the air cooling mode design, the frequency of the cold air blower 16 and the opening and closing of the cold air nozzle switch valve V5-V8 are adjusted through interlocking feedback; if the tool cutting force exceeds the upper limit of the air cooling mode design, the cutting fluid cooling unit is started, switched to the minimal lubrication mode, and the cold air nozzle switch valve V5-V8 is kept open. Open, start the cutting fluid nozzle regulating valve V9-V12, the cutting fluid supply pump 12, and the cutting waste liquid delivery pump 11, and control the cutting force of the machining tool by adjusting the frequency of the cutting fluid supply pump 12 and the opening of the cutting fluid nozzle regulating valve V9-V12; if the cutting force exceeds the design upper limit of the minimal lubrication mode, shut down the cold air blower 16 and the cold air nozzle switch valve V5-V8 in turn, and adjust the frequency of the cutting fluid supply pump 12 and the opening of the cutting fluid nozzle regulating valve V9-V12 through interlocking feedback as the cutting force changes.

[0026] The flexible and adjustable mixed-line machine tool spindle cooling system and method disclosed in the present invention innovatively integrates four cooling modes: traditional cutting fluid, minimal lubrication, dry air cooling, and circulating water cooling. It is equipped with temperature, flow, cutting force, and liquid level monitoring instruments, as well as corresponding interlocking regulating valves, switch valves, power equipment, etc., to form a flexible and adjustable mixed-line machine tool spindle cooling system. Based on the processing method of the above system, it innovatively proposes to dynamically optimize the cooling strategy by real-time monitoring of parameters such as spindle temperature and cutting force, thereby achieving flexible switching and parameter control between the four modes. Compared with the existing technology, this patent can enable mechanical processing to be carried out in a cooling mode and working condition that is more suitable for the processing state and working conditions, that is, it avoids damage to the machine tool caused by spindle overheating, rapid wear and workpiece damage caused by tool overheating, reduces processing heat damage, extends tool life, and improves processing efficiency, and avoids excessive consumption of cooling medium, increased carbon emissions, and environmental pollution caused by the over-protection cooling mode of mixed-line processing.

Claims

1. A flexible and adjustable mixed-line machine tool spindle cooling system, characterized in that: The cooling system includes a spindle cooling unit, a dry air cooling unit, a circulating cooling water unit and a cutting fluid cooling unit; The spindle cooling unit is composed of a spindle cooling medium inlet (1), a spindle (2), a spindle spiral fin (3), a spindle protective housing (4), a spindle cooling medium outlet (5), a machining tool (14) and a tool cooling nozzle (15); The dry air cooling unit is composed of a cold air blower (16), a cold air source (17), a cold air regulating valve V1, an exhaust valve V3 and N cold air nozzle switch valves; The circulating cooling water unit is composed of a cooling water storage tank (19), a cooling water supply pump (18), a condenser (7), a circulating cooling water inlet (6), a circulating cooling water outlet (8), a cooling water regulating valve V2 and a condensation regulating valve V4; The cutting fluid cooling unit is composed of a cutting fluid storage tank (9), a cutting fluid recovery device (10), a cutting fluid waste delivery pump (11), a cutting fluid supply pump (12), a cutting fluid waste storage tank (13), N cutting fluid nozzle regulating valves, and a cutting fluid waste regulating valve V13.

2. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1 is characterized in that: The spindle (2), the spindle spiral fin (3), the spindle protective housing (4), and the spindle cooling medium outlet (5) are connected in sequence from the inside to the outside, the spindle cooling medium inlet (1) is connected to the spindle spiral fin (3) inlet through the spindle protective housing (4), the spindle cooling medium outlet (5) is connected to the spindle spiral fin (3) outlet through the spindle protective housing (4), the machining tool (14) is connected to the lower end of the spindle (2), and N tool cooling nozzles (15) are located outside the machining tool (14); N is an even number greater than 2; The inlet of the cold air blower (16) is connected to the outlet of the cold air source (17), the outlet of the cold air blower (16) is connected to the inlet of the cold air regulating valve V1, the outlet of the cold air regulating valve V1 is connected to the inlet of the spindle cooling medium (1), the inlet of the exhaust valve V3 is connected to the outlet of the spindle cooling medium (5), and the outlet of the exhaust valve V3 is connected to the exhaust pipe; the inlets of the N cold air nozzle switch valves are all connected to the outlet of the cold air blower (16), and the outlets of the N cold air nozzle switch valves are respectively connected to the inlets of the N tool cooling nozzles (15); The inlet of the cooling water supply pump (18) is connected to the outlet of the cooling water storage tank (19), the outlet of the cooling water supply pump (18) is connected to the inlet of the cooling water regulating valve V2, the outlet of the cooling water regulating valve V2 is connected to the spindle cooling medium inlet (1), the spindle cooling medium outlet (5) is connected to the inlet of the condensation regulating valve V4, the outlet of the condensation regulating valve V4 is connected to the circulating cooling water inlet (6), the inlet of the condenser (7) is connected to the circulating cooling water inlet (6), the outlet of the condenser (7) is connected to the circulating cooling water outlet (8), and the circulating cooling water outlet (8) is connected to the inlet of the cooling water regulating valve V2; The outlet of the cutting fluid storage tank (9) is connected to the inlet of the cutting fluid supply pump (12), the outlets of the cutting fluid supply pump (12) are all connected to the inlets of N cutting fluid nozzle regulating valves, the outlets of the N cutting fluid nozzle regulating valves are respectively connected to the inlets of N tool cooling nozzles (15), the inlet of the cutting waste fluid storage tank (13) is connected to the outlet of the tool cooling nozzle (15), the outlet of the cutting waste fluid storage tank (13) is respectively connected to the cutting waste fluid delivery pump (11) and the cutting fluid supply pump (12), the outlet of the cutting waste fluid delivery pump (11) is connected to the inlet of the cutting fluid recovery device (10), and the outlet of the cutting fluid recovery device (10) is connected to the inlet of the cutting fluid storage tank (9).

3. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1 is characterized in that: The system also includes: 3 flow meters, 2 temperature meters, 3 liquid level meters, cutting force monitoring instrument C, The three flow meters are respectively located at the outlets of the cooling water supply pump (18), the cold air blower (16), and the cutting fluid supply pump (12); Two temperature instruments are respectively located between the spindle (2) and the spindle spiral fin (3) and at the circulating cooling water outlet (8); a cutting force monitoring instrument C is loaded on the spindle (2); and three liquid level instruments are respectively located on the side walls of the cooling water storage tank (19), the cutting waste liquid storage tank (13) and the cutting fluid storage tank (9).

4. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1 is characterized in that: The cooling water supply pump (18), cold air blower (16), and cutting fluid supply pump (12) are all frequency conversion devices, which are interlocked with three flow meters respectively and are all interlocked with the cutting force monitoring instrument C; the cooling water supply pump (18) is interlocked with the cooling water regulating valve V2 and the condensation regulating valve V4; the cold air blower (16) is interlocked with the cold air regulating valve V1, the exhaust valve V3, and the N cold air nozzle switch valves; the cutting fluid supply pump (12) is interlocked with the N cutting fluid nozzle regulating valves; the temperature meter T1 is interlocked with the cooling water supply pump (18), the cooling water regulating valve V2, the cold air blower (16), and the cold air regulating valve V1; the temperature meter T2 is interlocked with the power of the condenser (7); and the two liquid level meters are interlocked with the cutting waste liquid delivery pump (11) and the cutting waste liquid regulating valve V13.

5. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1 is characterized in that: The spindle (2), the spindle spiral fin (3), the spindle protective housing (4), and the spindle cooling medium outlet (5) are coaxially assembled from the inside to the outside, wherein the spindle spiral fin (3) is fastened to the inner wall surface of the spindle protective housing (4) by welding, riveting, or screwing; the spindle spiral fin (3) and the spindle protective housing (4) are integrally fastened to the spindle (2) and sealed to form a hollow space; the temperature meter T1 measuring point is placed at the bottom of the hollow space, and the lead direction and the meter head position are determined according to the machine tool space.

6. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1, characterized in that: The shaft cooling medium inlet (1) is located at the upper end of the main shaft protective housing (4), and is connected to the spiral flow channel of the main shaft spiral fin (3) through the main shaft protective housing (4); the main shaft cooling medium outlet (5) is located at the lower end of the main shaft protective housing (4), and is connected to the spiral flow channel of the main shaft spiral fin (3) through the main shaft protective housing (4); The tool cooling nozzle (15) adopts a dual-channel design, with a cold air channel located inside and a cutting fluid channel located outside, and the cold air channel and the cutting fluid channel are coaxial.

7. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1, characterized in that: The N tool cooling nozzles (15) are circumferentially distributed at equal distances and angles on the upper end of the machining tool (14) with the machining tool (14) as the center of the circle, and the nozzle axis is collinear with the normal of the machining tool (14); the inlet of the tool cooling nozzle (15) has two branches, which are respectively connected to the N cold air nozzle switch valves and the N cutting fluid nozzle regulating valves.

8. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1, characterized in that: The cutting waste liquid storage tank (13) is integrated at the bottom of the machine tool and is connected to the cutting fluid at the outlet of the tool cooling nozzle (15); the inlet of the cutting waste liquid delivery pump (11) is located at the bottom of the cutting waste liquid storage tank (13), and a discharge port is provided at the top of the cutting waste liquid storage tank (13).

9. The flexible and adjustable mixed-line machine tool spindle cooling system according to claim 1, characterized in that: The circulating cooling water inlet (6) and the circulating cooling water outlet (8) are respectively located at the lower end and the upper end of the condenser (7); the inlet of the cooling water supply pump (18) is located at the bottom of the cooling water storage tank (19); the inlet of the cutting fluid supply pump (12) is located at the bottom of the cutting fluid storage tank (9); and the outlet of the cutting fluid recovery device (10) is located at the top of the cutting fluid storage tank (9).

10. A flexible and adjustable cooling method for a mixed-line machine tool spindle, the method being applied to the system according to any one of claims 1 to 9, characterized in that: The following steps are involved: 1) The system uses a dry air cooling unit by default to cool the machine tool spindle. The cold air from the cold air source (17) passes through the cold air blower (16), the cold air regulating valve V1, the spindle cooling medium inlet (1), and enters the spiral flow channel of the shaft protection housing (4) and the spindle spiral fin (3) to cool the spindle (2). The cold air then flows out from the spindle cooling medium outlet (5) and is exhausted through the exhaust valve V3. The other valves remain normally closed and the power unit remains in a shutdown state. According to the display of the temperature instrument T1, if the spindle temperature fluctuates within the design upper and lower limits, the frequency of the cold air blower (16) and the opening of the cold air regulating valve V1 are adjusted through interlocking feedback. 2) According to the display of the temperature instrument T1, if the spindle temperature exceeds the upper limit of the air cooling mode, the circulating cooling water unit is switched to cool the machine tool spindle, the cold air regulating valve V1 and the exhaust valve V3 are closed, and the cooling water regulating valve V2, the condensation regulating valve V4, and the condenser (7) are opened; the cooling water from the cooling water storage tank (19) enters the spiral flow channel of the shaft protection shell (4) and the spindle spiral fin (3) through the cooling water supply pump (18), the cooling water regulating valve V2, and the spindle cooling medium inlet (1) in sequence to cool the spindle (2), and then flows out from the spindle cooling medium outlet (5), passes through the condensation regulating valve V4 and the condenser (7) to condense to form circulating cooling water, and then enters the spindle cooling unit through the cooling water regulating valve V2 again. After the circulation is stable, the cooling water supply pump (18) is automatically closed; according to the display of the temperature instrument T1, the spindle temperature is adjusted through the interlocking feedback to adjust the cooling water supply pump (18) frequency and the opening of the cooling water regulating valve V2; 3) The system uses a dry air cooling unit by default to cool the machining tool (14), and the cold air from the cold air source (17) is ejected in sequence through the cold air blower (16), N cold air nozzle switch valves, and the tool cooling nozzle (15) to cool the tool; other valves remain normally closed, and the power unit remains in a shutdown state; according to the display of the cutting force monitoring instrument C, if the cutting force fluctuates within the upper and lower limits of the air cooling mode design, the frequency of the cold air blower (16) and the opening and closing of the N cold air nozzle switch valves are adjusted through interlocking feedback; 4) According to the display of the cutting force monitoring instrument C, if the cutting force of the tool exceeds the upper limit of the air cooling mode, the cutting fluid cooling unit is started, and the tool is switched to the minimal lubrication mode. The N cold air nozzle switch valves are kept open, and the N cutting fluid nozzle regulating valves, the cutting fluid supply pump (12), and the cutting waste fluid delivery pump (11) are started; the cutting fluid from the cutting fluid storage tank (9) is sprayed out through the cutting fluid supply pump (12), the N cutting fluid nozzle regulating valves, and the tool cooling nozzle (15) to cool the tool; the flowing cutting fluid is collected in the cutting waste fluid storage tank (13) at the bottom of the machine tool, and enters the cutting fluid recovery device (10) through the cutting waste fluid delivery pump (11), and after being treated, it re-enters the cutting fluid storage tank (9) for recycling; if the cutting force fluctuates within the upper and lower limits of the minimal lubrication mode, the frequency of the cutting fluid supply pump (12) and the opening of the N cutting fluid nozzle regulating valves are adjusted through interlocking feedback; If the cutting force exceeds the upper limit of the minimal lubrication mode design, the cold air blower (16) and the N cold air nozzle switch valves are shut down in sequence, and as the cutting force changes, the frequency of the cutting fluid supply pump (12) and the opening of the N cutting fluid nozzle regulating valves are adjusted through interlock feedback; 5) According to the display of temperature instrument T2, the circulating cooling water temperature is fed back through the interlock to adjust the power of condenser (7); 6) According to the display of the two liquid level meters, the liquid levels of the cutting waste liquid storage tank (13) and the cutting fluid storage tank (9) are adjusted through interlock feedback to start and stop the cutting waste liquid delivery pump (11) and the frequency, and the opening of the cutting waste liquid regulating valve V13.

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