Center water outlet structure of machine tool spindle

Abstract

The utility model belongs to the technical field of machine tool equipment, and particularly relates to a center water outlet structure of a machine tool spindle. Comprises: a main shaft having a central axis; the water outlet is formed in the central axis of the main shaft; the cooling liquid channel extends to the water outlet from the rear part of the main shaft; the interface is arranged at the rear part of the main shaft and is used for supplying the cooling liquid to the cooling liquid channel; the connecting joint is used for connecting an external cooling system and enhancing the connecting stability of the main shaft and the connecting joint; the connecting joint comprises an internal and external thread seat arranged at the rear part of the main shaft; the nut is arranged on the outer side of the internal and external thread seat; the threaded connector is arranged in the internal and external threaded seat; the thread limiting sleeve is matched with the internal thread of the internal and external thread seat; the sealing washer is arranged between the threaded connector and the threaded limiting sleeve; the water pipe connector is arranged at the rear end of the threaded connector. The utility model provides a central water outlet structure of a machine tool spindle, which enhances the connection stability of the spindle and a water supply joint and enables the spindle and the water supply joint to be tightly connected.

Description

Technical Field

[0001] The utility model belongs to the technical field of machine tool equipment, and in particular relates to a central water outlet structure of a machine tool spindle. Background Art

[0002] After the CNC machine tool spindle is equipped with a tool, water needs to be discharged from the spindle during the processing to cool the blade and processed parts. However, the most common problem at this stage is that water leakage is easy to occur during the tool change and air exchange process, and the leaked water is left in the spindle. Over time, the spindle will rust inside, resulting in changes in accuracy; in severe cases, the spindle will be damaged. In addition, the structure is complex and difficult to assemble.

[0003] The utility model patent with publication number CN220093067U discloses a central water outlet structure of a machine tool spindle, including a fixing part, a connecting part and a control part; the fixing part includes a fixing seat and a water receiving tray fixed at the front end of the fixing seat; a through hole is provided at the axis of the water receiving tray, and an annular water receiving groove is provided at the end face close to the fixing seat, and a drainage port for drainage is provided on the outer wall of the water receiving groove; the connecting part includes a rotating part with a T-shaped structure, the rotating part is slidably installed with the fixing seat along the axis, and an L-shaped water channel connected at both ends is provided in the rotating part; the control part is coaxially fixedly installed with the fixing seat, and can drive the connecting part to move along the axis; when the connecting part is at any extreme position at both ends, the water channel outlet in the axial direction is located inside the fixing seat.

[0004] The central water outlet structure of the machine tool spindle adopts the method of adding a water tray and a built-in rotary joint. Although this technology effectively avoids the rust problem caused by water accumulation in the spindle, the connection stability of the water supply joint of the spindle of this technology is poor when it is in use. It is easy for the connected water supply pipe to fall off due to excessive water supply pressure, which affects the water outlet of the machine tool spindle to cool the blade and processed parts, and the assembly effect is not good. Utility Model Content

[0005] The utility model aims to solve the above-mentioned technical problems and provides a central water outlet structure of a machine tool spindle which can strengthen the stability of the connection between the spindle and the water supply joint so as to enable the spindle to be tightly connected.

[0006] In view of this, the utility model provides a central water outlet structure of a machine tool spindle, comprising:

[0007] A spindle, having a central axis;

[0008] A water outlet is arranged on the central axis of the main shaft;

[0009] A coolant channel extending from the rear of the spindle to the water outlet for supplying coolant to cool the blade and the machined parts;

[0010] An interface, disposed at the rear of the spindle, for supplying coolant to the coolant channel;

[0011] The connecting joint is arranged at the rear of the main shaft, the connecting joint is connected with the interface, and is used to connect to the external cooling system to enhance the stability of the connection between the main shaft and the connecting joint;

[0012] The connection connector includes:

[0013] An internal and external thread seat is arranged at the rear of the spindle and is connected with the interface;

[0014] A nut is arranged outside the internal and external thread seat, and the nut is matched with the external thread of the internal and external thread seat;

[0015] The threaded connector is arranged inside the internal and external threaded seat, and the threaded connector is matched with the internal threads of the internal and external threaded seat;

[0016] The thread limit sleeve cooperates with the internal thread of the internal and external thread seat, and the thread limit sleeve is located at the rear side of the threaded connector;

[0017] A sealing gasket is arranged between the threaded connector and the threaded limiting sleeve, and the threaded limiting sleeve presses the sealing gasket tightly;

[0018] The water pipe joint is arranged at the rear end of the threaded connector, and the water pipe joint coincides with the central axis of the main shaft.

[0019] In the above technical solution, further, the coolant channel passes through the main shaft and is connected to the water outlet so as to effectively guide the coolant to the water outlet.

[0020] In any of the above technical solutions, further, the coolant channel extends along the axial direction of the main shaft and forms a coolant outlet at the water outlet.

[0021] In any of the above technical solutions, further, a blocking mechanism for blocking the coolant from flowing to the coolant outlet is provided on the outer side of the middle portion of the spindle, and the blocking mechanism includes:

[0022] A groove is provided on the right side of the middle of the spindle, and the groove is connected with the coolant channel;

[0023] A blocking block is slidably arranged in the groove;

[0024] A rubber bump is arranged on the left side of the blocking block, the rubber bump is located inside the coolant channel and is slidably connected with the groove;

[0025] The mounting plate is arranged at the upper and lower ends of the right side of the main shaft by bolt connection;

[0026] A guide rail is arranged on the front side of the mounting plate and is fixedly connected to the main shaft;

[0027] Slide blocks are slidably arranged on the guide rails, and both slide blocks are connected to the blocking blocks;

[0028] A connecting plate, arranged on the front right side of the guide rail;

[0029] A guide rod is arranged on the right side of the slide block, and the guide rod is slidably connected with the connecting plate;

[0030] A buffer spring is sleeved on the guide rod and arranged between the slider and the connecting plate;

[0031] A rack, arranged on the upper rear side of the guide rail;

[0032] The cylinder is arranged on the frame, and the cylinder piston rod is connected with the slider.

[0033] In any of the above technical solutions, further, a drain port is provided at the bottom of the main shaft for discharging the coolant remaining in the coolant channel, the drain port runs through the main shaft and is connected to the coolant channel, and a sealing cover is slidably provided in the drain port.

[0034] In any of the above technical solutions, further, the coolant channel has a smooth coating or nano coating on the inner surface to reduce flow resistance and improve cooling efficiency.

[0035] The beneficial effects of the utility model are:

[0036] 1. A stable physical connection is formed between the connecting joint and the spindle. The use of threaded fitting, nut fixing and sealing gasket effectively prevents the loosening or leakage of the connecting parts, ensures the reliable supply of coolant and the stable operation of the system, and provides the required sealing effect, effectively preventing coolant leakage, maintaining the sealing of the system, and ensuring stable connection;

[0037] 2. The cylinder controls the movement of the piston rod to control the operation of the entire blocking mechanism, thereby blocking the connection of the coolant channel and preventing the coolant from flowing to the coolant outlet, thus avoiding water leakage during tool change. This effectively controls the opening and closing of the coolant channel, thereby achieving precise control and regulation of the coolant flow direction, ensuring that the machine tool spindle will not leak during tool change, and improving stable operation and effective cooling;

[0038] 3. In order to drain the coolant that may remain in the coolant channel, directly access the drain port, move the sliding sealing cover to open the drain port, and the coolant remaining in the coolant channel can be smoothly discharged from the spindle through the drain port, preventing the coolant from remaining in the spindle. Over time, the inside of the spindle will rust and cause changes in accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0040] Figure 2 It is a planar cross-sectional view of the utility model;

[0041] Figure 3 It is a three-dimensional cross-sectional view of the utility model;

[0042] Figure 4 It is an exploded view of the connection joint of the utility model;

[0043] Figure 5 It is a three-dimensional structural schematic diagram of the blocking mechanism of the utility model;

[0044] Figure 6 It is a partial three-dimensional structural schematic diagram of the blocking mechanism of the utility model;

[0045] The reference numerals in the figure are: 1. spindle; 2. water outlet; 3. coolant channel; 4. interface; 5. connecting joint; 51. internal and external threaded seat; 52. nut; 53. threaded connector; 54. threaded limit sleeve; 55. sealing gasket; 56. water pipe joint; 6. coolant outlet; 7. blocking mechanism; 71. groove; 72. block; 73. rubber bump; 74. mounting plate; 75. guide rail; 76. slider; 77. connecting plate; 78 guide rod; 79. buffer spring; 710. frame; 711. cylinder; 8. drain outlet; 9. sealing cover. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0047] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0048] Embodiment 1:

[0049] like Figure 1-Figure 4 As shown, this embodiment provides a central water outlet structure of a machine tool spindle 1, comprising:

[0050] A main shaft 1 having a central axis;

[0051] The water outlet 2 is arranged on the central axis of the main shaft 1;

[0052] A coolant channel 3 extends from the rear of the spindle 1 to the water outlet 2 and is used to supply coolant to cool the blade and the processed parts;

[0053] An interface 4 is provided at the rear of the spindle 1 and is used to supply coolant to the coolant channel 3;

[0054] The connecting joint 5 is arranged at the rear of the main shaft 1, and is connected to the interface 4, and is used to connect to an external cooling system to enhance the stability of the connection between the main shaft 1 and the connecting joint 5;

[0055] The connection joint 5 comprises:

[0056] The internal and external thread seat 51 is arranged at the rear of the main shaft 1 and communicated with the interface 4;

[0057] A nut 52 is disposed outside the internal and external thread seat 51, and the nut 52 cooperates with the external thread of the internal and external thread seat 51;

[0058] The threaded connector 53 is disposed inside the internal and external threaded seat 51, and the threaded connector 53 cooperates with the internal threads of the internal and external threaded seat 51;

[0059] The threaded limiting sleeve 54 cooperates with the internal thread of the internal and external thread seat 51, and the threaded limiting sleeve 54 is located at the rear side of the threaded connector 53;

[0060] The sealing gasket 55 is arranged between the threaded connector 53 and the threaded limiting sleeve 54, and the threaded limiting sleeve 54 presses the sealing gasket 55;

[0061] The water pipe joint 56 is arranged at the rear end of the threaded connector 53 , and the water pipe joint 56 coincides with the central axis of the main shaft 1 .

[0062] In the present technical solution, the spindle 1 has a central axis, and the water outlet 2 is arranged on the central axis of the spindle 1, and is used to lead the coolant out of the spindle 1. The coolant channel 3 extends from the rear of the spindle 1 to the water outlet 2, and its function is to transport the coolant to the working area of ​​the blade and the processed parts for effective cooling and lubrication. The interface 4 is arranged at the rear of the spindle 1, and is used to receive the coolant and introduce it into the coolant channel 3. The connecting joint 5 connects the external cooling system to the spindle 1 to ensure the stable supply of the coolant. The internal and external threaded seat 51 is arranged at the rear of the spindle 1, and is connected to the interface 4 to ensure that the coolant can smoothly enter the spindle 1 system. The nut 52 is located on the outside of the internal and external threaded seat 51, and cooperates with the external thread of the internal and external threaded seat 51. The existence of the nut 52 ensures the safe fixation of the connecting joint 5 to prevent it from being accidentally loosened or falling off. The threaded connector 53 is arranged inside the internal and external threaded seat 51, and is tightly matched with the internal thread of the internal and external threaded seat 51. This design ensures that the coolant can enter the spindle 1 system through the connector. The threaded limit sleeve 54 is located at the rear side of the threaded connector 53 and cooperates with the internal thread of the internal and external threaded seat 51. Its function is to limit the position of the threaded connector 53 to ensure the stability and safety of the connection. The sealing gasket 55 is arranged between the threaded connector 53 and the threaded limit sleeve 54 and is pressed by the threaded limit sleeve 54. This configuration effectively prevents coolant leakage, maintains the sealing of the system, and ensures a stable connection. The water pipe joint 56 is arranged at the rear end of the threaded connector 53 and coincides with the central axis of the main shaft 1. Such a design enables the water supply pipe of the external cooling system to be tightly connected to the main shaft 1 system to avoid accidental falling off or movement of the pipe.

[0063] During operation, first, threadedly connect the threaded connector 53 to the internal and external threaded seat 51. After connection, slip the nut 52 over the internal and external threaded seat 51 and turn the nut 52 so that it locks and fixes with the external thread of the internal and external threaded seat 51 during rotation. The presence of the nut 52 ensures the secure fixation of the connection joint 5, preventing accidental loosening or detachment. Next, slip the sealing washer 55 over the threaded connector 53. Then, slip the threaded limit sleeve 54 over the threaded connector 53 and rotate the threaded limit sleeve 54. The threaded limit sleeve 54 mates with the internal thread of the internal and external threaded seat 51, so that the threaded limit sleeve 54 screws into the internal and external threaded seat 51 and is fixedly connected thereto. The threaded limit sleeve 54 restricts the position of the threaded connector 53, ensuring the stability and safety of the connection. At the same time, the threaded limit sleeve 54 presses the sealing washer 55 to ensure its correct position and provide the required sealing effect, effectively preventing coolant leakage and maintaining the system's sealing property, while ensuring stable connection. When in use, install the water supply pipe at the water pipe joint 56. Through the stable connection of the connection joint 5 with the main shaft 1, it is ensured that the water supply pipe will not fall off or become loose due to excessive water supply pressure, improving the stability of the main shaft 1 and the connection joint 5. Through the above design, the connection joint 5 and the main shaft 1 form a stable physical connection. The thread fit, the fixation of the nut 52, and the use of the sealing washer 55 effectively prevent the loosening or leakage problems of the connecting parts, ensuring the reliable supply of coolant and the stable operation of the system, and distributing it to the cutting tool and the machining part through the coolant channel 3 to maintain stable temperature and lubrication conditions during the machining process.

[0064] As Figure 2 , Figure 3 and Figure 6 shown, in this embodiment, optimally, the coolant channel 3 passes through the main shaft 1 and communicates with the water outlet 2 to effectively guide the coolant to the water outlet 2.

[0065] In this technical solution, first, the coolant channel 3 is provided to effectively guide the coolant inside the main shaft 1. The design of the coolant channel 3 can ensure that the coolant can flow inside the main shaft 1 and transfer heat throughout the main shaft 1 structure, which is very important for maintaining the temperature stability of the main shaft 1 during high-speed operation, because the main shaft 1 may be affected by high temperature during the machining process. The central water outlet structure of the machine tool main shaft 1 effectively guides the coolant to the water outlet 2 through the design of the coolant channel 3 to maintain the stable temperature of the main shaft 1 during operation, thereby ensuring the normal operation of the machine tool equipment and the stability of the machining quality.

[0066] As Figure 2 , Figure 3 and Figure 6 shown, in this embodiment, optimally, the coolant channel 3 extends along the axial direction of the main shaft 1 and forms a coolant outlet 6 at the water outlet 2.

[0067] In the present technical solution, the coolant channel 3 extends along the axial direction of the spindle 1, and finally forms a coolant outlet 6 at the water outlet 2. Such a design can ensure that the coolant flows in the spindle 1 and is released at the water outlet 2, thereby effectively supplying the coolant to the tool and processed parts.

[0068] Embodiment 2:

[0069] This embodiment provides a central water outlet structure of a machine tool spindle 1, which, in addition to the technical solutions of the above-mentioned embodiments, also has the following technical features.

[0070] like Figure 1 , Figure 5 and Figure 6 As shown, in this embodiment, the optimized outer side of the middle of the spindle 1 is provided with a blocking mechanism 7 for blocking the coolant from flowing to the coolant outlet 6, and the blocking mechanism 7 includes:

[0071] A groove 71 is provided on the right side of the middle of the spindle 1, and the groove 71 is connected to the coolant channel 3;

[0072] A blocking block 72 is slidably disposed in the groove 71;

[0073] The rubber protrusion 73 is arranged on the left side of the blocking block 72. The rubber protrusion 73 is located inside the coolant channel 3 and is slidably connected with the groove 71.

[0074] The mounting plate 74 is arranged at the upper and lower ends of the right side of the main shaft 1 by bolt connection;

[0075] A guide rail 75 is disposed on the front side of the mounting plate 74 and is fixedly connected to the main shaft 1;

[0076] Slide blocks 76 are slidably disposed on the guide rail 75, and both slide blocks 76 are connected to the blocking block 72;

[0077] A connecting plate 77 is arranged on the front right side of the guide rail 75;

[0078] A guide rod 78 is disposed on the right side of the slider 76, and the guide rod 78 is slidably connected to the connecting plate 77;

[0079] The buffer spring 79 is sleeved on the guide rod 78 and arranged between the slider 76 and the connecting plate 77;

[0080] The frame 710 is arranged on the upper side of the rear portion of the guide rail 75;

[0081] The cylinder 711 is disposed on the frame 710 , and the piston rod of the cylinder 711 is connected to the slider 76 .

[0082] In the present technical scheme, there is a groove 71 on the right side of the middle part of the spindle 1, and a sliding block 72 is arranged inside the groove 71. The block 72 can move along the direction of the groove 71. A rubber protrusion 73 is installed on the left side of the block 72. This protrusion is located inside the coolant channel 3 and is connected to the groove 71. The function of the rubber protrusion 73 is to block the coolant from flowing to the coolant outlet 6 when changing the tool to avoid water leakage during the tool changing process. The mounting plate 74 is fixed to the upper and lower ends of the right side of the spindle 1 by bolts. The guide rail 75 is arranged on the front side of the mounting plate 74 and is fixed to the spindle 1 to ensure the stability and position accuracy of the guide rail 75. Two sliders 76 are slidably mounted on the guide rail 75 and are connected to the block 72. The connecting plate 77 is arranged on the front right side of the guide rail 75. The guide rod 78 is mounted on the right side of the slider 76. The guide rod 78 is slidably connected to the connecting plate 77. The buffer spring 79 is sleeved on the guide rod 78 and is located between the slider 76 and the connecting plate 77 to play a role in buffering and stabilizing sliding. The frame 710 is arranged on the upper side of the rear part of the guide rail 75 , and the cylinder 711 is installed on the frame 710 , and its piston rod is connected to the slider 76 .

[0083] When it is necessary to block the coolant from flowing to the coolant outlet 6, the cylinder 711 controls the operation of the entire blocking mechanism 7 by controlling the movement of the piston rod. When the piston rod of the cylinder 711 extends, the slider 76 moves along the guide rail 75, and the slider 76 drives the guide rod 78 to move along the connecting plate 77. The buffer spring 79 is compressed. At the same time, the slider 76 drives the blocking block 72 and the rubber protrusion 73 to move. The slider 76 and the rubber protrusion 73 move along the groove 71 into the coolant channel 3, so that the rubber protrusion 73 blocks the coolant channel 3, thereby blocking the connection of the coolant channel 3 and preventing the coolant from flowing to the coolant outlet 6, avoiding the occurrence of tool change. In the process of water leakage, after the tool change is completed, on the contrary, when the piston rod of the cylinder 711 is retracted, the positions of the slider 76 and the guide rod 78 are changed, so that the block 72 and the rubber protrusion 73 also move accordingly, and the rubber protrusion 73 moves outward to the groove 71. At this time, the rubber protrusion 73 can prevent the coolant from flowing out of the groove 71 and allow the coolant channel 3 to be reconnected so that the coolant can flow to the coolant outlet 6. In this way, the opening and closing of the coolant channel 3 is effectively controlled, thereby realizing the precise control and adjustment of the coolant flow direction, ensuring that the machine tool spindle 1 will not leak during the tool change process, and improving stable operation and effective cooling.

[0084] Embodiment 3:

[0085] This embodiment provides a central water outlet structure of a machine tool spindle 1, which, in addition to the technical solutions of the above-mentioned embodiments, also has the following technical features.

[0086] like Figure 2 and Figure 3As shown, in this embodiment, it is optimized that a drain port 8 is provided at the bottom of the main shaft 1 for discharging the coolant remaining in the coolant channel 3. The drain port 8 runs through the main shaft 1 and is connected to the coolant channel 3. A sealing cover 9 is slidably provided in the drain port 8.

[0087] In the present technical solution, during the tool changing process of the machine tool spindle 1, the rubber protrusion 73 blocks the connection of the coolant channel 3. In order to discharge the coolant that may remain in the coolant channel 3, the operator directly accesses the drain port 8 and moves the sliding sealing cover 9 to open the drain port 8. Once the sealing cover 9 is opened, the coolant remaining in the coolant channel 3 can be smoothly discharged from the spindle 1 through the drain port 8. After the drainage is completed, the operator can move the sliding sealing cover 9 again to seal the drain port 8 to ensure the normal function and closure of the coolant channel 3 when the spindle 1 is restarted. This design makes it easy to manage and maintain the flow and discharge of the coolant during the operation cycle of the machine tool spindle 1, preventing the coolant from being left in the spindle 1. Over time, the inside of the spindle 1 will rust, resulting in changes in accuracy.

[0088] Embodiment 4:

[0089] This embodiment provides a central water outlet structure of a machine tool spindle 1, which, in addition to the technical solutions of the above-mentioned embodiments, also has the following technical features.

[0090] like Figure 2 , Figure 3 and Figure 6 As shown, in this embodiment, the coolant channel 3 is optimized to have a smooth coating or nano coating on the inner surface to reduce flow resistance and improve cooling efficiency.

[0091] In the present technical solution, the inner surface of the smooth coating or nano coating can significantly reduce the friction resistance of the coolant inside the channel. The traditional rough surface will cause greater resistance when the fluid flows, thus affecting the flow rate and flow of the coolant. The use of smooth coating or nano coating allows the coolant to pass through the channel more smoothly, reducing energy loss and improving the efficiency of the cooling system; the smooth coating or nano coating on the inner surface of the coolant channel 3 can improve the heat transfer performance of the coolant. The smoothness of the surface makes it easier for the coolant to contact the surface of the spindle 1, effectively absorbing and taking away the heat generated by the spindle 1. At the same flow rate, the coolant can take away the heat more quickly, improving the overall cooling efficiency. This is of great significance for protecting the machine tool spindle 1 from overheating, helping to extend the service life of the equipment and improve its working stability; the use of a smooth coating or a nano-coating can reduce the energy consumption of the cooling system. Due to the improved cooling efficiency, the need for frequent maintenance of the cooling system may be reduced, reducing operating costs and equipment downtime. The use of a smooth coating or a nano-coating in the coolant channel 3 can significantly improve the cooling performance and operating efficiency of the machine tool spindle 1, while reducing energy consumption and maintenance costs. It is one of the important technological innovations in the design of modern high-performance machine tools.

[0092] The embodiments of the present application are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A central water outlet structure of a machine tool spindle (1), characterized in that: include: A main shaft (1) having a central axis; A water outlet (2) is arranged on the central axis of the main shaft (1); A coolant channel (3) extending from the rear of the spindle (1) to the water outlet (2) for supplying coolant to cool the blade and the processed parts; An interface (4) is arranged at the rear of the spindle (1) and is used to supply coolant to the coolant channel (3); A connecting joint (5) is arranged at the rear of the main shaft (1), the connecting joint (5) is in communication with the interface (4), and is used to connect to an external cooling system to enhance the stability of the connection between the main shaft (1) and the connecting joint (5); The connecting joint (5) comprises: An internal and external threaded seat (51) is arranged at the rear of the main shaft (1) and is connected to the interface (4); A nut (52) is arranged outside the internal and external thread seat (51), and the nut (52) cooperates with the external thread of the internal and external thread seat (51); A threaded connector (53) is disposed inside the internal and external threaded seat (51), and the threaded connector (53) cooperates with the internal threads of the internal and external threaded seat (51); A threaded limiting sleeve (54) is matched with the internal thread of the internal and external thread seat (51), and the threaded limiting sleeve (54) is located at the rear side of the threaded connector (53); A sealing gasket (55) is arranged between the threaded connector (53) and the threaded limiting sleeve (54), and the threaded limiting sleeve (54) presses the sealing gasket (55); A water pipe joint (56) is arranged at the rear end of the threaded connector (53), and the water pipe joint (56) coincides with the central axis of the main shaft (1).

2. A central water outlet structure for a machine tool spindle (1) according to claim 1, characterized in that: The coolant channel (3) passes through the main shaft (1) and is connected to the water outlet (2) so as to effectively guide the coolant to the water outlet (2).

3. A central water outlet structure of a machine tool spindle (1) according to claim 2, characterized in that: The coolant channel (3) extends along the axial direction of the main shaft (1) and forms a coolant outlet (6) at the water outlet (2).

4. A central water outlet structure for a machine tool spindle (1) according to claim 3, characterized in that: A blocking mechanism (7) is provided on the outer side of the middle portion of the main shaft (1) for blocking the coolant from flowing to the coolant outlet (6), and the blocking mechanism (7) comprises: A groove (71) is provided on the right side of the middle of the main shaft (1), and the groove (71) is connected to the coolant channel (3); A blocking block (72) is slidably disposed in the groove (71); A rubber convex block (73) is arranged on the left side of the blocking block (72), the rubber convex block (73) is located inside the cooling liquid channel (3) and is slidably connected to the groove (71); A mounting plate (74) is arranged at the upper and lower ends of the right side of the main shaft (1) by means of bolt connection; A guide rail (75) is arranged on the front side of the mounting plate (74), and the guide rail (75) is fixedly connected to the main shaft (1); A slider (76) is slidably disposed on the guide rail (75), and both sliders (76) are connected to the block (72); A connecting plate (77) is arranged on the front right side of the guide rail (75); A guide rod (78) is arranged on the right side of the sliding block (76), and the guide rod (78) is slidably connected to the connecting plate (77); A buffer spring (79) is sleeved on the guide rod (78) and is arranged between the slider (76) and the connecting plate (77); A frame (710) is arranged on the upper rear side of the guide rail (75); The cylinder (711) is arranged on the frame (710), and the piston rod of the cylinder (711) is connected to the slider (76).

5. The central water outlet structure of a machine tool spindle (1) according to claim 1, characterized in that: The main shaft (1) has a drain port (8) at the bottom thereof for discharging the coolant remaining in the coolant channel (3); the drain port (8) passes through the main shaft (1) and is connected to the coolant channel (3); a sealing cover (9) is slidably provided in the drain port (8).

6. A central water outlet structure for a machine tool spindle (1) according to claim 1, characterized in that: The cooling liquid channel (3) has a smooth coating or a nano coating on the inner surface to reduce flow resistance and improve cooling efficiency.

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