High-precision numerical control machine tool shaft structure
By designing an external water-cooling mechanism and air-cooling system on the electric spindle, the problems of narrow heat dissipation space and rapid wear are solved, achieving efficient heat dissipation and improved stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG MAIXINGTU INTELLIGENT EQUIP CO LTD
- Filing Date
- 2025-05-13
- Publication Date
- 2026-06-23
Smart Images
Figure CN224389992U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of CNC machine tool technology, and specifically to an axial structure for a high-precision CNC machine tool. Background Technology
[0002] An electric spindle is a transmission structure that integrates an electric motor and a machine tool spindle into one unit. It features high speed, high precision, and low noise. Its internal structure includes a housingless motor, spindle, bearings, spindle unit housing, drive module, and cooling system. This integrated design ensures stability and durability during high-speed rotation. It is suitable for various CNC machine tools, such as machining centers, CNC lathes, grinding machines, and drilling machines, meeting diverse machining needs. However, electric spindles generate significant heat during high-speed rotation. If not cooled promptly, the temperature will rise, causing thermal expansion of the spindle material, leading to decreased precision and even machining errors.
[0003] A search revealed that application CN222002811U discloses a drilling center electric spindle. This spindle mounts drilling tools via a connector. During drilling operations, the spindle body drives the connector and heat dissipation structure to rotate. The airflow generated by the rotation of the heat sinks in the heat dissipation structure carries away the heat transferred to the front cover of the main body, resulting in good heat dissipation. This also prevents dust and drilling particles from entering the spindle's interior, ensuring stable and reliable operation.
[0004] However, certain defects and deficiencies still exist and need to be optimized. The specific defects and deficiencies are as follows: The end face of the mounting ring in the electric spindle of the drilling center is formed by an inclined surface. The inclined surface forms a contact fit or clearance fit with the inner wall of the accommodating cavity, and the heat dissipation space is limited and narrow, which makes it easy to cause mechanical wear and slow heat dissipation during operation. At the same time, because it is closer to the workpiece being processed, the waste particles and dust generated during processing are more likely to block the heat dissipation space and affect heat dissipation. Therefore, it is necessary to design a high-precision CNC machine tool axial structure to solve the problems mentioned in the background technology. Utility Model Content
[0005] The purpose of this utility model is to provide a shaft structure for a high-precision CNC machine tool. This shaft structure effectively solves the technical problems in existing drilling center electric spindles where the end face of the mounting ring is formed by an inclined surface, which forms a contact fit or clearance fit with the inner wall of the accommodating cavity, and the heat dissipation space is limited and narrow. This leads to easy mechanical wear and slow heat dissipation during operation. At the same time, because it is closer to the workpiece being processed, waste particles and dust generated during processing are more likely to block the heat dissipation space, affecting heat dissipation.
[0006] To achieve the above objectives, this utility model provides the following technical solution:
[0007] A high-precision CNC machine tool's axial structure includes an electric spindle housing for the high-precision CNC machine tool. A motor rotor is movably mounted near the center inside the electric spindle housing. A front shaft is fixedly connected to the end of the motor rotor near the workpiece. The front shaft is composed of a thick shaft and a thin shaft. A front end cover is fixedly mounted on the end face of the electric spindle housing near the front shaft. An external water-cooling mechanism is provided on the side of the front end cover away from the electric spindle housing. The external water-cooling mechanism includes a shaft cooling water jacket sleeved on the outer surface of the thin shaft and a mounting column fixedly mounted on the side of the front end cover away from the electric spindle housing. A mounting end plate is fixedly mounted on the end of the shaft cooling water jacket away from the thick shaft. The mounting end plate and the mounting column are fixedly connected by locking bolts. A refrigerant inlet head is fixedly mounted on the top of the outer surface of the shaft cooling water jacket. Refrigerant outlet holes are opened around the perimeter of the mounting end plate near the outer surface of the thin shaft. A sealing ring is embedded between the shaft cooling water jacket and the thin shaft.
[0008] As a preferred embodiment of this utility model, the thin shaft body is located at the end of the thick shaft body away from the motor rotor. A first ball bearing is embedded and installed on the end face of the thick shaft body near the shaft cooling water jacket. A second ball bearing is embedded and installed on the outer surface of the thin shaft body near the mounting end plate. A chuck is provided at the end of the thin shaft body away from the thick shaft body. A front radial bearing and a front radial sensor are provided on the outer surface of the thick shaft body near the interior of the electric spindle housing.
[0009] As a preferred embodiment of this utility model, a motor stator is provided around the outer surface of the motor rotor, and a rear shaft is fixedly connected to the end of the motor rotor away from the front shaft.
[0010] As a preferred embodiment of this utility model, the outer surface of the rear shaft is sequentially provided with a rear radial bearing and a rear radial sensor, a double-sided axial thrust bearing and an axial sensor, and a rear auxiliary bearing. The rear radial bearing and the rear radial sensor are located near the motor rotor, and a cooling fan is fixedly installed at the end of the rear shaft away from the motor rotor.
[0011] As a preferred embodiment of this utility model, a mounting bushing is fixedly installed on the outer surface of the electric spindle housing near the front end cover, and a rear end cover with air holes is fixedly installed on the end of the electric spindle housing away from the front end cover.
[0012] As a preferred embodiment of this utility model, the front end cover and the outer housing of the electric spindle are fixedly connected by fixing bolts. A front auxiliary bearing is embedded in the side of the front end cover near the inside of the outer housing of the electric spindle. Several sets of assembly and installation through holes distributed in a ring are opened around the mounting bushing.
[0013] Compared with the prior art, the beneficial effects of this utility model are:
[0014] In this invention, the external water-cooling mechanism can quickly absorb the heat generated by the motor spindle through an external water-cooling system, thereby facilitating efficient heat dissipation without being limited by heat dissipation space, reducing mechanical wear, and providing a fast heat dissipation rate. Simultaneously, the water absorbed can be drained to reduce dust on the machining head. This effectively solves the technical problems of existing drilling center electric spindles where the mounting ring has a beveled end face, creating a contact or clearance fit between the bevel and the inner wall of the accommodating cavity, resulting in limited and narrow heat dissipation space. This leads to mechanical wear and slow heat dissipation during operation. Furthermore, because it is closer to the workpiece, waste particles and dust generated during processing are more likely to clog the heat dissipation space, affecting heat dissipation. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the overall three-dimensional external structure of this utility model;
[0016] Figure 2 A three-dimensional external structure diagram of the external water-cooling mechanism in this utility model;
[0017] Figure 3 This is a schematic diagram of the overall planar internal structure of this utility model;
[0018] Figure 4 This is a partially enlarged structural diagram of part A in this utility model.
[0019] In the diagram: 1. Electric spindle housing; 11. Motor rotor; 111. Front shaft; 1111. Coarse shaft; 1112. Fine shaft; 1113. First ball bearing; 1114. Second ball bearing; 1115. Chuck; 1116. Front radial bearing; 1117. Front radial sensor; 112. Motor stator; 113. Rear shaft; 1131. Rear radial bearing; 1132. Rear radial sensor; 1133. Double-sided axial thrust bearing; 1 134. Axial sensor; 1135. Rear auxiliary bearing; 1136. Cooling fan; 12. Front end cover; 121. Fixing bolt; 122. Front auxiliary bearing; 13. Mounting bushing; 131. Assembly mounting through hole; 14. Rear end cover with vent; 2. External water cooling mechanism; 21. Shaft cooling water jacket; 22. Mounting column; 23. Mounting end plate; 24. Locking bolt; 25. Refrigerant inlet head; 26. Refrigerant outlet hole; 27. Sealing ring. Detailed Implementation
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.
[0021] Example:
[0022] This utility model provides an axial structure for a high-precision CNC machine tool. This axial structure effectively solves the technical problems in existing drilling center electric spindles where the end face of the mounting ring is formed by an inclined surface, and the inclined surface forms a contact fit or clearance fit with the inner wall of the accommodating cavity. Furthermore, the heat dissipation space is limited and narrow, which leads to easy mechanical wear and slow heat dissipation during operation. At the same time, because it is closer to the workpiece being processed, waste particles and dust generated during processing are more likely to block the heat dissipation space, affecting heat dissipation.
[0023] Please see Figures 1-4 This utility model provides a technical solution:
[0024] A shaft structure for a high-precision CNC machine tool includes an electric spindle housing 1 for the high-precision CNC machine tool. A motor rotor 11 is movably installed inside the electric spindle housing 1 near the center. A mounting bushing 13 is fixedly installed on the outer surface of the electric spindle housing 1 near the front end cover 12. A rear end cover 14 with air holes is fixedly installed at the end of the electric spindle housing 1 away from the front end cover 12.
[0025] A front shaft 111 is fixedly connected to the end of the motor rotor 11 closest to the workpiece. A motor stator 112 is provided around the outer surface of the motor rotor 11. A rear shaft 113 is fixedly connected to the end of the motor rotor 11 away from the front shaft 111. The front cover 12 and the outer housing 1 of the electric spindle are fixedly connected by fixing bolts 121. A front auxiliary bearing 122 is embedded in the side of the front cover 12 closest to the inside of the outer housing 1 of the electric spindle. Several sets of assembly and installation through holes 131 arranged in a ring are opened around the mounting bushing 13. The motor rotor 11 rotates in the magnetic field generated by the motor stator 112, thereby converting electrical energy into mechanical energy.
[0026] The front rotating shaft 111 is composed of a thick shaft body 1111 and a thin shaft body 1112. A front end cover 12 is fixedly installed on one end face of the electric spindle housing 1 near the front rotating shaft 111. An external water cooling mechanism 2 is provided on the side of the front end cover 12 away from the electric spindle housing 1. The external water cooling mechanism 2 includes a shaft cooling water jacket 21 sleeved on the outer surface of the thin shaft body 1112 and a mounting column 22 fixedly installed on the side of the front end cover 12 away from the electric spindle housing 1. A mounting end plate 23 is fixedly installed on the end of the shaft cooling water jacket 21 away from the thick shaft body 1111. The mounting end plate 23 and the mounting column 22 are fixedly connected by locking bolts 24. A refrigerant inlet head 25 is fixedly installed on the top of the outer surface of the shaft cooling water jacket 21. Refrigerant outlet holes 26 are opened around the outer surface of the mounting end plate 23 near the thin shaft body 1112. A tight-fitting device is embedded between the shaft cooling water jacket 21 and the thin shaft body 1112. The sealing ring 27 and the refrigerant inlet head 25 are connected to an external refrigerant source, and the refrigerant enters the shaft cooling water jacket 21 to absorb heat from the rotating shaft body, thereby helping it to dissipate heat efficiently. At the same time, the refrigerant after absorbing heat can be discharged from the refrigerant outlet hole 26 to reduce dust on the machining head. The external water cooling mechanism 2 is located at the end of the electric spindle housing 1 near the machining head, so it is not limited by the heat dissipation space, reducing mechanical wear and providing fast heat dissipation. Meanwhile, the sealing ring 27 can effectively prevent the refrigerant from seeping out from the other end of the shaft cooling water jacket 21 away from the refrigerant outlet hole 26, achieving a waterproof function. The front rotating shaft 111 is composed of a thick shaft body 1111 and a thin shaft body 1112, which can form a height difference to further achieve a waterproof function. The shaft cooling water jacket 21 and the front cover 12 can be fixedly installed by the design of the mounting end plate 23, mounting column 22, and locking bolt 24.
[0027] Furthermore, in this embodiment, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4The thin shaft 1112 is located at the end of the thick shaft 1111 away from the motor rotor 11. A first ball bearing 1113 is embedded in the end face of the thick shaft 1111 near the shaft cooling water jacket 21. A second ball bearing 1114 is embedded in the outer surface of the thin shaft 1112 near the mounting end plate 23. A chuck 1115 is provided at the end of the thin shaft 1112 away from the thick shaft 1111. A front radial bearing 1116 and a front radial sensor 1117 are provided on the outer surface of the thick shaft 1111 near the interior of the electric spindle housing 1. A rear radial bearing 1131 and a rear radial sensor 1132, a double-sided axial thrust bearing 1133 and an axial sensor 1134, and a rear auxiliary bearing 1135 are sequentially provided on the outer surface of the rear shaft 113. The rear radial bearing 1131 and the rear radial sensor 1132 are located near the motor rotor 11, while the rear shaft 113 is located away from the motor rotor 11. A cooling fan 1136 is fixedly mounted on one end of the motor rotor 11. The design of the first ball bearing 1113 and the second ball bearing 1114 makes the shaft run more smoothly. The main function of the front radial bearing 1116 and the rear radial bearing 1131 is to support the spindle, reduce friction, and ensure that the spindle can rotate smoothly and at high speed. At the same time, the main function of the front radial sensor 1117 and the rear radial sensor 1132 is to monitor the spindle speed and angular displacement, ensuring the stability and accuracy of the electric spindle when it is running at high speed. The main function of the double-sided axial thrust bearing 1133 is to bear and balance the axial thrust, ensure the axial positioning of the shaft system, and reduce friction and wear. Meanwhile, the axial sensor 1134 is mainly used to measure the movement of an object in the linear direction. It is usually composed of two bearings, one of which is fixed on the object being measured and the other is fixed on the measuring device. When the object being measured moves, the relative displacement between the bearings will cause the sensor to output a corresponding electrical signal, thereby realizing displacement measurement. The auxiliary bearing 1135, combined with the front auxiliary bearing 122, mainly supports the spindle, reduces friction and wear, and improves machining accuracy and stability. Under the action of the shaft, the cooling fan 1136 rotates accordingly. Combined with the rear end cover 14 with air holes, it can provide air cooling for the outer housing 1 of the electric spindle, further improving the overall heat dissipation effect. This can effectively prevent the material of the electric spindle from thermally expanding, which could lead to a decrease in accuracy or even machining errors.
[0028] It should be noted that the principle of electric spindle is existing technology, and will not be elaborated on here.
[0029] In this embodiment, the specific implementation scenario is as follows: First, the refrigerant inlet 25 is connected to an external refrigerant source, and then the whole system starts to operate. The motor rotor 11 rotates in the magnetic field generated by the motor stator 112, and the refrigerant enters the shaft cooling water jacket 21 to absorb heat from the rotating shaft, thereby helping it to dissipate heat efficiently. At the same time, the refrigerant after absorbing heat can be discharged from the refrigerant outlet hole 26 to reduce dust on the machining head. The external water cooling mechanism 2 is externally located at the end of the electric spindle housing 1 near the machining head. Compared with the existing drilling center electric spindle, it is not limited by heat dissipation space, reduces mechanical wear, and has a fast heat dissipation rate.
[0030] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A shaft structure for a high-precision CNC machine tool, comprising an outer housing (1) for an electric spindle of the high-precision CNC machine tool, characterized in that: Inside the outer housing (1) of the electric spindle, a motor rotor (11) is movably mounted near the center. A front shaft (111) is fixedly connected to the end of the motor rotor (11) near the workpiece. The front shaft (111) is composed of a thick shaft body (1111) and a thin shaft body (1112). A front end cover (12) is fixedly mounted on the end face of the outer housing (1) of the electric spindle near the front shaft body (111). An external water cooling mechanism (2) is provided on the side of the front end cover (12) away from the outer housing (1). The external water cooling mechanism (2) includes a shaft cooling water jacket (21) sleeved on the outer surface of the thin shaft body (1112) and a fixed... A mounting column (22) is installed on the side of the front end cover (12) away from the outer housing (1) of the electric spindle. A mounting end plate (23) is fixedly installed on the end of the shaft cooling water jacket (21) away from the thick shaft body (1111). The mounting end plate (23) and the mounting column (22) are fixedly connected by locking bolts (24). A refrigerant inlet head (25) is fixedly installed on the top of the outer surface of the shaft cooling water jacket (21). A refrigerant outlet hole (26) is opened around the outer surface of the mounting end plate (23) near the thin shaft body (1112). A sealing ring (27) is embedded between the shaft cooling water jacket (21) and the thin shaft body (1112).
2. The axial structure of a high-precision CNC machine tool according to claim 1, characterized in that: The thin shaft (1112) is located at the end of the thick shaft (1111) away from the motor rotor (11). The first ball (1113) is embedded in the end face of the thick shaft (1111) near the shaft cooling water jacket (21). The second ball (1114) is embedded in the outer surface of the thin shaft (1112) near the mounting end plate (23). A chuck (1115) is provided at the end of the thin shaft (1112) away from the thick shaft (1111). A front radial bearing (1116) and a front radial sensor (1117) are provided on the outer surface of the thick shaft (1111) near the inside of the electric spindle outer housing (1).
3. The axial structure of a high-precision CNC machine tool according to claim 1, characterized in that: The motor rotor (11) is provided with a motor stator (112) around its outer surface, and a rear shaft (113) is fixedly connected to the end of the motor rotor (11) away from the front shaft (111).
4. The axial structure of a high-precision CNC machine tool according to claim 3, characterized in that: The outer surface of the rear shaft (113) is sequentially provided with a rear radial bearing (1131) and a rear radial sensor (1132), a double-sided axial thrust bearing (1133) and an axial sensor (1134), and a rear auxiliary bearing (1135). The rear radial bearing (1131) and the rear radial sensor (1132) are located near the motor rotor (11), and a cooling fan (1136) is fixedly installed at the end of the rear shaft (113) away from the motor rotor (11).
5. The axial structure of a high-precision CNC machine tool according to claim 1, characterized in that: An mounting bushing (13) is fixedly installed on the outer surface of the electric spindle housing (1) near the front end cover (12), and a rear end cover (14) with air holes is fixedly installed on the end of the electric spindle housing (1) away from the front end cover (12).
6. The axial structure of a high-precision CNC machine tool according to claim 5, characterized in that: The front cover (12) and the outer housing of the electric spindle (1) are fixedly connected by fixing bolts (121). The front cover (12) is embedded with a front auxiliary bearing (122) on the side of the electric spindle outer housing (1) near the inside. The mounting bushing (13) has several sets of assembly and installation through holes (131) arranged in a ring around it.