Rear motor spindle of numerically controlled lathe

Abstract

The invention discloses a rear motor main shaft of a numerical control lathe, which relates to the technical field of processing machine tools and consists of a rotor assembly, a machine body assembly, a front bearing assembly, a rear bearing assembly, a front end cover, a rear end cover, a motor shell assembly, an encoder assembly and an oil cylinder flange. The rigidity, machining precision and efficiency of the spindle are improved, and the high-precision and high-rotating-speed requirements are met. And the oil cylinder flange and the rotor seat are designed in a split manner, so that the mounting and dismounting convenience and the customizable degree are improved. The stator assembly is made of high-quality magnetic materials, the magnetic circuit design is optimized, and heating is reduced. The motor shell assembly is made of efficient heat dissipation materials and designed, and effective heat dissipation is ensured. A traditional motor stator assembly is difficult to maintain through integrated glue pouring, the stator assembly and the motor shell are detachable in a split mode, the problems of installation complexity and later maintenance are solved, and environmental pollution and human body harm are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of machining machine tools, in particular to a rear motor spindle of a numerically controlled lathe. Background Art

[0002] As an important type of machine tool, lathe is widely used in the processing of various parts. As the core component of the lathe, the performance of the electric spindle is of vital importance to the processing accuracy, speed and stability of the lathe. The spindle of the traditional lathe adopts mechanical transmission methods such as belts or gears. This method is not only inefficient, but also easy to cause errors and vibrations, affecting the accuracy and quality of the processed parts. There are some unavoidable problems in the structural design of the traditional spindle. The traditional spindle relies on gears or belt transmission as the main connection method. Taking gear transmission as an example, the gear transmission design on the spindle can obtain a very accurate transmission ratio, high speed and high rigidity, but gear transmission also means that the overall spindle structure will occupy a very large machine tool space. After the gear transmission has been in operation for a long time, a series of problems may occur, such as the gear fatigue strength reaching the limit, the gear surface has pitting of the tooth surface under oil and high temperature, and the surface wear and transmission gap.

[0003] The existing rear motor manufacturing process is relatively complicated. The motor housing is cast by aluminum liquid, the stator assembly is embedded in it, and then the mold is cast and glued. After glue pouring, the stator assembly is completely integrated with the motor housing and cannot be separated normally. After years of use, if there is an abnormality inside the motor and maintenance is required, it will be quite difficult and the cost of use will increase significantly. Moreover, after glue pouring, the entire stator assembly is wrapped and occupies a large volume inside the motor, which reduces the heat dissipation efficiency of the motor and increases the burden on the motor.

[0004] The existing rotor assembly and cylinder flange of the motor rear spindle are all integrated designs. The magnetic ring needs to be assembled before the stator assembly. Since the rotor assembly contains strong permanent magnets, it is difficult to install and disassemble, and it is easy to cause pollution during assembly. After the rotor assembly and stator assembly are assembled, the magnetic ring cannot be disassembled, the coaxiality between the magnetic ring and the shaft core cannot be adjusted, and the degree of customization is low. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a lathe spindle with a motor at the rear, in view of the deficiencies of the above-mentioned prior art, and in particular to a lathe spindle with a motor at the rear, which has strong radial load-bearing capacity, high precision and high torque.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A rear motor spindle of a CNC lathe, comprising: A rotor assembly is rotatably disposed in the machine body with a central axis; The body component is a hollow structure used to support and accommodate other components; The front bearing assembly and the rear bearing assembly are respectively arranged at the front and rear parts of the machine body and are used to support the rotor assembly; The front cover and the rear cover are respectively arranged at the front and rear ends of the machine body and are used to close the machine body; The motor housing assembly is installed at the rear end of the machine body and is used to accommodate the stator assembly; A stator assembly cooperates with a rotor assembly to generate electromagnetic force; an encoder assembly for detecting a rotational position and speed of the rotor assembly; The oil cylinder flange is arranged at one end of the rotor assembly and is used for connecting the oil cylinder.

[0007] Furthermore, the rotor assembly includes a shaft core, a rotor seat locking nut, a rotor seat and a rotor magnetic part. One end of the shaft core passes through the front bearing assembly, the rear bearing assembly and the motor housing assembly and extends into the cylinder flange, and the other end extends out to be connected to the machine tool chuck for transmission. The rotor magnetic part is installed on the rotor seat, and the rotor seat is arranged at the rear end of the shaft core. The rotor seat and the shaft core are both provided with symmetrical flat key grooves. The shaft core is connected to the rotor seat by embedding a flat key. The rotor seat locking nut is fitted with the end face of the rotor seat and is tightened through the external thread at the rear end of the shaft core to achieve the purpose of tightening the rotor seat.

[0008] Furthermore, the body assembly includes a body, and a front bearing assembly and a rear bearing assembly are arranged in the through holes at the upper and lower parts of the body, a stator assembly is arranged in the through hole in the middle part of the motor housing assembly, and the rotor assembly is axially arranged in the inner cavity of the stator assembly and supported by the front bearing assembly and the rear bearing assembly. The front end cover is arranged under the body and fixed by screws, and the rear end cover is installed on the rear end mounting cavity of the body. The motor housing assembly is installed on the rear end flange of the body, and the fastening ring is fastened to the front end of the body by screws. When the spindle is installed in the spindle box of the machine tool, the rear end uses screws to pass through the through holes of the body flange to lock the body, and the front end is fixed by the fastening ring to ensure the stability of the spindle during use.

[0009] Furthermore, the stator assembly includes a stator jacket for circulating coolant, a stator core in a circular ring shape, and stator winding groups respectively arranged at both ends of the stator core, the stator core is arranged on the outside of the rotor magnetic part, the stator core is formed by stacking and pressing a plurality of silicon steel sheets of equal height, the stator winding group is formed by winding a plurality of enameled wires of equal diameter, a thermistor is arranged in the stator winding group, the stator winding group is electrically connected to a three-phase AC power supply through a power cord, the rotor magnetic part is evenly inlaid with permanent magnets, the stator jacket is sleeved on the outside of the stator core, and the outer circle of the stator jacket is provided with a coolant water channel groove, which can quickly cool the temperature of the stator when it is working.

[0010] Furthermore, a cooling water connector is provided on one side of the motor housing assembly, and a power line plug and a coding line connector are provided on the other side.

[0011] Furthermore, the front bearing assembly includes a plurality of first front high-speed angular contact bearings and second front high-speed angular contact bearings stacked in the vertical direction and sleeved on the front end of the shaft core, as well as a front double-row cylindrical roller bearing, a front bearing spacer ring A and a front bearing spacer ring B, and is pre-tightened by a front bearing locking nut; The rear bearing assembly includes a rear bearing spacer ring C, a rear double-row roller bearing, a rear bearing spacer ring D and a rear bearing locking nut, which are respectively installed. The front bearing locking nut and the rear bearing locking nut are both provided with a number of threaded holes, and organic screwdrivers are provided in the several threaded holes to tighten and prevent loosening. The front double-row cylindrical roller bearing and the rear double-row roller bearing are slightly adjusted in clearance through the tapered inner hole. The taper of the spindle inner hole is 1:12. The inner ring is moved axially to make it expand and deform radially, so as to adjust the radial rigidity and preload. The front bearing spacer ring A, the front bearing spacer ring B, the rear bearing spacer ring C and the rear bearing spacer ring D are all designed with water retaining rings and labyrinth dustproof structures to prevent dust, cuttings and other particles generated during the turning process from damaging and polluting the inside of the spindle.

[0012] Furthermore, the front end cover and the rear end cover are provided with a labyrinth groove, which cooperates with the labyrinth grooves of the front bearing spacer ring A and the rear bearing spacer ring D to form a labyrinth structure. The rear end cover is installed on the rear end mounting cavity of the body assembly, and the front end cover is provided with an annular confluence groove and a plurality of discharge holes.

[0013] Furthermore, the motor housing assembly can be detachably mounted on the mounting cavity at the rear end of the body assembly and fastened by screws. The motor housing assembly includes a motor housing and a plurality of cooling medium connectors. The motor housing is integrally cast and has a cooling medium flow channel designed inside. After being assembled with the stator assembly, a complete circulating water cooling system is formed. A plurality of cooling medium connector screw holes, a power cord interface, an encoder cord interface and an encoder mounting position are arranged on the outside of the motor housing.

[0014] Furthermore, the encoder assembly includes a hollow magnetic ring arranged on the outer circle of the rotor seat, an encoder reader arranged on the motor housing, and an encoder reader bracket. The hollow magnetic ring is provided with a plurality of countersunk holes for fixing and the outer circle of the hollow magnetic ring is provided with a zero point. The cylinder flange at the rear end of the hollow magnetic ring is a detachable design. After the cylinder flange is removed, the hollow magnetic ring can be debugged at any time according to different client requirements, which also facilitates subsequent maintenance work. The encoder reader is fastened to the encoder reader bracket by screws. The encoder reader bracket is provided with a plurality of waist-shaped holes for adjusting the sensing distance between the encoder reader and the encoder magnetic ring during assembly.

[0015] Furthermore, the cylinder flange is provided with a threaded hole connected to the cylinder, the shaft core is provided with a shaft core inner hole through which a connecting rod can be passed through a claw, and the cylinder flange is locked to the rear end of the shaft core by a locking nut and simultaneously locks the rotor seat.

[0016] The present invention provides a rear motor spindle for a CNC lathe. Compared with the prior art, it has the following beneficial effects: 1. The front bearing assembly adopts a new arrangement structure, and uses large-size grease-lubricated angular contact bearings and double-row cylindrical roller bearings, which improves the axial and radial rigidity, processing accuracy and processing efficiency of the spindle, and solves the current market demand for high-precision and high-speed applications of the spindle; 2. The cylinder flange and rotor seat are designed to be split. After the cylinder flange is removed, the encoder assembly can be debugged and replaced according to the requirements of different machine tools, which greatly improves the convenience of installation and disassembly and the degree of customization, and solves the problem of low versatility in the spindle market; 3. When the motor is working, the high-speed rotation of the main shaft will generate a lot of heat energy. Therefore, the present invention has very strict requirements on the structural design of the stator component cooling system and thermal stability. By using high-quality magnetic materials with high magnetic permeability and low remanence ratio, the hysteresis and eddy current losses are reduced. The electromagnetic field simulation software is used to analyze the motor magnetic circuit, optimize the geometric dimensions of the magnetic circuit and the layout of the magnetic materials. Silicon steel sheets of appropriate thickness and material are selected, and coating treatment is performed to reduce contact resistance; 4. Reasonable design of the magnetic circuit of the rotor assembly makes its heat generation extremely low. The motor housing assembly adopts efficient heat dissipation materials and design, and the outer shell is made of aluminum heat dissipation plate to improve heat exchange efficiency; 5. The cooling system is designed with a reasonable circulation path to ensure that the cooling medium effectively absorbs and removes heat. After the stator assembly of a traditional motor is embedded in the motor housing, it is molded and filled with glue as a whole. If the coil or other components are abnormal, they need to be destroyed and the glue injection is difficult to maintain or the motor is directly discarded; 6. The stator assembly and the motor housing are designed as a split and detachable structure. The coil and the water channel jacket of the stator assembly are designed as one body. Sealing rings are provided at the front and back, and a positioning mechanism is designed on the motor housing. This not only solves the problems of cumbersome early installation and difficult later maintenance caused by the integrated structure, but also reduces the environmental pollution and harm to the human body caused by the casting glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-sectional view of the overall internal structure of the main shaft of the lathe with a rear motor according to the present invention.

[0018] Figure 2 It is a structural schematic diagram of the spindle pre-tightening structure of the lathe with a rear motor according to the present invention.

[0019] Figure 3 It is a schematic structural diagram of the spindle rotor assembly of a lathe with a rear motor according to the present invention.

[0020] Figure 4 It is a schematic diagram of the structure of the exterior of the main shaft of the lathe with the motor rear-mounted according to the present invention.

[0021] Figure 5 It is a schematic diagram of the structure of the motor-rear-mounted lathe spindle motor of the present invention.

[0022] In the figure: 1. rotor assembly; 2. machine body assembly; 3. front bearing assembly; 4. rear bearing assembly; 5. front end cover; 6. rear end cover; 7. motor housing assembly; 8. stator assembly; 9. encoder assembly; 10. cylinder flange; 11. shaft core; 12. rotor seat locking nut; 13. rotor seat; 14. rotor magnetic part; 15. machine body; 16. fastening ring; 17. front bearing locking nut; 18. front bearing spacer ring B; 19. first front high-speed angular contact bearing; 20. second front high Angular contact bearing; 21. Front double-row cylindrical roller bearing; 22. Front bearing spacer A; 23. Rear bearing locking nut; 24. Rear bearing spacer D; 25. Rear double-row roller bearing; 26. Rear bearing spacer C; 27. Cooling medium connector; 28. Motor housing; 29. ​​Stator winding group; 30. Stator core; 31. Stator jacket; 32. Magnetic ring; 33. Encoder reader; 34. Encoder reader bracket; 35. Flat key; 36. Power cord connector; 37. Encoder line interface. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1-5 The present invention provides a technical solution: a rear motor spindle of a CNC lathe, comprising a cylinder flange 10, a body assembly 2, a front bearing assembly 3, a rear bearing assembly 4, a front end cover 5, a rear end cover 6 and a motor housing assembly 7, a stator assembly 8, and an encoder assembly 9, which are respectively installed on a rotor assembly 1. The cylinder flange 10, the motor housing assembly 7 and the encoder assembly 9 are sequentially installed on one side of the body assembly 2, the front end cover 5 and the fastening ring 16 are sequentially installed on the other side of the body assembly 2, the rotor assembly 1, the front bearing assembly 3, and the rear bearing assembly 4 are respectively installed in the body 15, the bearing assembly is composed of a front bearing assembly 3 and a rear bearing assembly 4 respectively arranged at both ends of a shaft core 11, the stator assembly 8 is sleeved on the outside of the rotor assembly 1, one end of the rotor assembly 1 is penetrated in the motor housing assembly 7, and is drivably connected to the cylinder flange 10, and the other end is a tapered inner hole and a threaded hole designed for connecting a chuck.

[0025] Among them, the rotor assembly 1 includes an axis core 11, a rotor magnetic part 14, a rotor seat locking nut 12 and a rotor seat 13. The rotor assembly 1 can be rotatably arranged in the body 15 around the central axis. One end of the axis core 11 passes through the rear bearing assembly 4 and the motor housing assembly 7 and extends into the cylinder flange 10, and the other end passes through the front bearing assembly 3. The rotor seat 13 is installed at the rear position of the axis core 11. The rotor magnetic part 14 is arranged on the outer circle of the rotor seat 13. The rotor magnetic part 14 is evenly provided with a plurality of inlay grooves and evenly inlaid with a plurality of permanent magnets. The rotor seat 13 is locked to the rear end of the axis core 11 through the rotor seat locking nut 12, and the rotor assembly is locked.

[0026] Among them, the stator assembly 8 includes a stator jacket 31 provided with a circulating cooling water tank, a ring-shaped stator core 30 and a stator winding group 29 respectively arranged at the upper and lower ends of the stator core 30, the stator core 30 is arranged on the outside of the rotor magnetic part 14, the stator core 30 is formed by stacking and pressing a plurality of silicon steel sheets of equal height, the stator winding group 29 is wound by a plurality of enameled wires of equal diameter, a thermistor is arranged in the stator winding group 29, the stator winding group 29 is electrically connected to the three-phase AC power supply through a power cord, the stator jacket 31 is sleeved on the outside of the stator core 30, the outer circle of the stator jacket 31 is provided with a coolant water channel groove, which can quickly cool the temperature of the stator when working, and the upper and lower ends of the stator jacket are provided with a plurality of sealing ring grooves to prevent the loss of coolant.

[0027] Among them, the front bearing assembly 3 is composed of a plurality of first front high-speed angular contact bearings 19, second front high-speed angular contact bearings 20, front double-row cylindrical roller bearings 21, front bearing spacer rings A22 and front bearing spacer rings B18 stacked in the vertical direction and sleeved on the front end of the shaft core 11, and is pre-tightened by the front bearing locking nut 17. The front end cover 5 is close to the outer ring end face of the front double-row cylindrical roller bearing 21, the front bearing spacer ring A22 is supported on the flange end face of the shaft core 11 and supports the inner ring of the front double-row cylindrical roller bearing 21, and the front bearing spacer ring B18 is close to the inner ring end face of the first front high-speed angular contact bearing 19 and then pre-tightened by the front bearing locking nut 17. The rear bearing assembly 4 includes a rear bearing spacer ring C26, a rear double-row roller bearing 25, a rear bearing spacer ring D24 and a rear bearing locking nut 23 which are installed respectively. The rear bearing spacer ring C is sleeved on the rear end shoulder of the shaft core 11 and supports the inner ring of the rear double-row roller bearing 25. The outer ring of the rear double-row roller bearing 25 rests on the inner end surface of the rear end cavity of the body. The rear end cover is installed in the installation cavity of the body and presses the outer ring of the rear double-row roller bearing 25. The rear bearing spacer ring D24 is stacked on the inner ring of the rear double-row roller bearing 25 and is pre-tightened by the rear bearing locking nut 23. The front bearing locking nut 17 and the rear bearing locking nut 23 are both provided with a plurality of threaded holes, and machine screws are provided in the plurality of threaded holes to tighten and prevent loosening. The dynamic balance of the main shaft can also be adjusted by the machine screws. The front double-row cylindrical roller bearing 21 and the rear double-row roller bearing 25 can adjust the clearance slightly through the conical inner hole. The taper of the spindle inner hole is 1:12. The inner ring is moved axially to make it expand and deform radially, so as to adjust the radial rigidity and preload. The front bearing spacer A22, the front bearing spacer B18, the rear bearing spacer C26 and the rear bearing spacer D24 are designed with water retaining rings and labyrinth dustproof structures to prevent dust, cutting and other particles generated during turning from damaging and polluting the inside of the spindle.

[0028] Among them, the front end cover 5 is provided with a receiving groove and a leakage liquid discharge hole, the receiving groove is connected with the shaft core drainage groove, and the rear end cover 6 is installed on the rear end installation cavity of the body 15. The front end cover 5 and the rear end cover 6 are both provided with a plurality of sealing ring grooves and labyrinth grooves and cooperate with the front bearing spacer ring A22 and the rear bearing spacer ring D24 to form a complete labyrinth structure.

[0029] The motor housing assembly 7 is installed on the installation cavity at the rear end of the machine body 15 and fastened by screws. The motor housing assembly is a motor housing 28 and a plurality of cooling medium connectors 27, including a plurality of "O" type sealing rings and positioning screws. The motor housing 28 is integrally cast and has a cooling medium flow channel designed inside. After being assembled with the stator jacket 31, a complete circulating water cooling system is formed. A plurality of cooling medium connector screws, a power line connector 36, an encoder line interface 37 and an encoder installation position are arranged on the outside of the housing. The stator assembly power line and the thermistor signal line are connected to an external driver or machine tool through the line interface arranged in the motor housing 28.

[0030] Among them, the cylinder flange 10 is provided with a threaded hole for connecting the driving cylinder, the shaft core 11 is provided with a shaft core inner hole through which the pull rod can pass, the cylinder flange 10 is sleeved on the boss of the rotor seat 13 and locked by a number of screws, and the rotor seat 13 is locked by the rotor seat locking nut 12.

[0031] Among them, the encoder assembly 9 includes an encoder magnetic ring 32 and an encoder head bracket 34 and an encoder head 33 arranged on the motor housing 28. The encoder magnetic ring 32 is sleeved on the boss of the rotor seat 13, and the screws lock the magnetic ring on the rotor seat 13 through a plurality of countersunk holes on the end face. The encoder head 33 is tightly locked on the encoder head bracket 34. The sensing distance between the encoder head 33 and the encoder magnetic ring 32 is adjusted by a plurality of waist-shaped grooves arranged on the encoder head bracket 34.

[0032] The present invention discloses a lathe spindle with a rear motor having a strong radial bearing capacity and high precision and high torque, wherein the front end cover 5 is installed at the front end of the machine body 15, and the front bearing spacer ring A22 is installed at the rear end face of the flying disc of the shaft core 11 by sleeve installation, wherein the front bearing spacer ring A22 and the front bearing spacer ring B18 form a structure with multiple bends and interlocking rings, but do not contact with each other and leave a certain amount of gap, and at the same time, the inner side of the front bearing spacer ring A22 and the outer side of the flying disc of the shaft core 11 are provided with a water throwing trough. During operation, foreign matters such as debris and cutting chips outside the machine body will be blocked by the water throwing trough of the shaft core 11 under the high-speed rotation of the rotor assembly, and a small amount of cutting fluid or sewage will be blocked by the labyrinth groove formed by the cooperation of the front bearing spacer ring A22 and the front bearing spacer ring B18 and the water throwing trough inside the front bearing spacer ring A22, and finally, the fluid will be ejected through a plurality of drainage holes at the lower side of the front bearing spacer ring A22 along the annular confluence groove provided by the front bearing spacer ring A22, thereby protecting the normal operation of the spindle.

[0033] Secondly, the coolant is connected to the cooling medium joint 27 and enters the coolant circulation channel interconnected by the motor housing 28 and the stator jacket 31. The upper and lower ends of the stator jacket 31 are provided with multiple layers of sealing rings to form a closed cooling cycle. After circulating in the cooling water channel, it flows into the refrigerator through the coolant outlet joint. Since the coolant circulates back and forth on the outer wall of the stator jacket 31 for many times and reciprocates, it effectively takes away most of the heat energy generated by the stator and the coil, thereby ensuring the stable and continuous operation of the spindle motor at low temperatures.

[0034] During the working process, the actual temperature of the spindle can be monitored in real time through the temperature sensor installed in the stator, so as to effectively protect the normal operation of the electric spindle. The whole electric spindle adopts an adjustable dynamic balance design. In addition to adjusting the balance amount during assembly by the adjusting nuts 17 and 23 at the front and rear ends, the dynamic balance amount can also be adjusted after the spindle is assembled through the many balance holes set on the cylinder flange 10 and the front end of the shaft core 11.

[0035] The present invention replaces the pulley at the rear end of the spindle of a traditional mechanical lathe with a more compact motor assembly. The motor assembly includes a motor housing assembly 7, a stator assembly 8 and a rotor assembly 1. The rotor assembly 1 is installed at the rear end of the shaft core 11. The stator assembly 8 is installed at the rear end of the body 15 corresponding to the rotor assembly 1. The shaft core 11 rotates at high speed under the drive of the rotor assembly 1, thereby forming a spindle structure with the motor at the rear. Designing the motor at the rear end of the spindle can not only provide torque for the spindle, but also solve the problem of uneven force on the rear end of the spindle due to belt pulling, which affects the spindle rotation accuracy. At the same time, the versatility of the spindle is maintained. On the basis that the front end of the spindle composed of the body assembly 2, the front bearing assembly 3, the rear bearing assembly 4, the front cover 5 and the rear cover 6 remain unchanged, it can be directly installed in the spindle of the existing mechanical spindle, and can be directly replaced without unnecessary operation steps, which greatly solves the problem of low versatility in the spindle market. On this basis, the motor assembly is optimized, and the rotor assembly 1 and the cylinder flange 10 are designed to be split. The cylinder flange 10 is positioned through the boss of the rotor seat 13, avoiding the influence of coaxiality differences caused by the split structure, and a number of countersunk holes are provided on the flange end surface to firmly fix it on the rotor seat. Below the cylinder flange 10 is the hollow magnetic ring 32. If the magnetic ring needs to be disassembled or replaced, just loosen the cylinder flange screws, making the rear-end rotor structure more concise and more convenient and quick to debug.

[0036] The present invention eliminates the traditional filling method of the motor casting mold and glue filling, thereby designing a new type of combined fixing structure. Several sealing structures and positioning structures are set on the stator jacket 31 in the stator assembly 8, wherein the stator core 30 and the stator jacket 31 are designed to be assembled into one and then installed in the motor housing 28. The sealing ring on the stator jacket 31 can prevent the coolant from leaking and prevent foreign matter or sewage from entering the motor coolant flow channel. It also has a certain degree of centering effect, and then the positioning structure set in the motor housing 28 locks the position so that the stator assembly will not move. Designing the motor housing 28 and the stator assembly 8 to be detachable greatly reduces the cumbersomeness of producing the motor, and facilitates the maintenance of the spindle in the later stage, saving the spindle maintenance cost.

[0037] When the present invention is working, the motor is started by an external driver, and the motor rotor uses a permanent magnet to generate a fixed magnetic field. When the stator current generates a rotating magnetic field, it interacts with the magnetic field of the permanent magnet to generate torque. According to the instructions of the machine tool system, the frequency converter controls the start and stop, acceleration and deceleration, and steering of the motor. The spindle speed is monitored by the encoder and the information is fed back to the frequency converter. When the spindle reaches the set speed, the cutting process can be started. During the processing, the machine tool system can also adjust the spindle speed according to the processing requirements. Directly driving the spindle through the motor can provide better rigidity, higher precision and more stable processing performance, and reduce the kinetic energy loss and vibration caused by the belt drive.

[0038] Those skilled in the art should understand that the technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A rear motor spindle for a CNC lathe, characterized in that: include: A rotor assembly (1) is rotatably disposed in the machine body with its central axis; The body component (2) is a hollow structure used to support and accommodate other components; A front bearing assembly (3) and a rear bearing assembly (4) are respectively arranged at the front and rear parts of the machine body and are used to support the rotor assembly (1); A front cover (5) and a rear cover (6), respectively arranged at the front and rear ends of the machine body, and used to close the machine body; A motor housing assembly (7) mounted at the rear end of the machine body and used to accommodate the stator assembly (8); The stator assembly (8) cooperates with the rotor assembly (1) to generate electromagnetic force; An encoder assembly (9) for detecting the rotational position and speed of the rotor assembly (1); The oil cylinder flange (10) is arranged at one end of the rotor assembly (1) and is used for connecting to the oil cylinder.

2. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The rotor assembly (1) comprises a shaft core (11), a rotor seat locking nut (12), a rotor seat (13) and a rotor magnetic member (14); one end of the shaft core (11) passes through a front bearing assembly (3), a rear bearing assembly (4) and a motor housing assembly (7) and extends into a cylinder flange (10); the other end extends out to be transmission-connected to a machine tool chuck; the rotor magnetic member (14) is mounted on the rotor seat (13); the rotor seat (13) is arranged at the rear end of the shaft core (11); the rotor seat (13) and the shaft core (11) are both provided with symmetrical flat keyways; the shaft core (11) is connected to the rotor seat (13) by embedding a flat key (35); the rotor seat locking nut (12) is fitted with an end surface of the rotor seat (13) and is tightened via an external thread at the rear end of the shaft core (11) to achieve the purpose of fastening the rotor seat.

3. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The machine body assembly (2) comprises a machine body (15), wherein the through holes at the upper and lower parts of the machine body (15) are provided with a front bearing assembly (3) and a rear bearing assembly (4), and the through hole at the middle part of the motor housing assembly (7) is provided with a stator assembly (8). The rotor assembly (1) is axially arranged in the inner cavity of the stator assembly (8) and supported by the front bearing assembly (3) and the rear bearing assembly (4). The front end cover (5) is arranged below the machine body (15) and fixed by screws, and the rear end cover (6) is installed on the rear end installation cavity of the machine body (15). The motor housing assembly (7) is installed on the rear end flange of the machine body (15), and the fastening ring (16) is fastened to the front end of the machine body by screws. When the spindle is installed on the spindle box of the machine tool, the rear end is screwed through the through hole of the flange of the machine body (15) to lock the machine body (15), and the front end is fixed by the fastening ring (16) to ensure the stability of the spindle when in use.

4. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The stator assembly (8) comprises a stator jacket (31) for circulating coolant, a stator core (30) in an annular shape, and stator winding groups (29) respectively arranged at two ends of the stator core (30), the stator core (30) being arranged outside the rotor magnetic part (14), the stator core (30) being formed by stacking and pressing a plurality of silicon steel sheets of equal height, the stator winding group (29) being formed by winding a plurality of enameled wires of equal diameter, a thermistor being arranged inside the stator winding group (29), the stator winding group (29) being electrically connected to a three-phase AC power supply via a power line, the rotor magnetic part (14) being evenly inlaid with permanent magnets, the stator jacket (31) being sleeved on the outside of the stator core (30), the outer circumference of the stator jacket (31) being provided with a coolant water channel groove, which can quickly cool the temperature of the stator when it is working.

5. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The motor housing assembly (7) is provided with a cooling water connector on one side, and a power line plug and a coding line connector on the other side.

6. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The front bearing assembly (3) comprises a plurality of first front high-speed angular contact bearings (19) and second front high-speed angular contact bearings (20) stacked in a vertical direction and sleeved on the front end of the shaft core (11), as well as a front double-row cylindrical roller bearing (21), a front bearing spacer ring A (22) and a front bearing spacer ring B (18), and is pre-tightened by a front bearing locking nut (17); The rear bearing assembly (4) comprises a rear bearing spacer ring C (26), a rear double-row roller bearing (25), a rear bearing spacer ring D (24) and a rear bearing locking nut (23) which are respectively installed. The front bearing locking nut (17) and the rear bearing locking nut (23) are both provided with a plurality of threaded holes, and a screwdriver is provided in each of the plurality of threaded holes for tightening and preventing loosening. The front double-row cylindrical roller bearing (21) and the rear double-row roller bearing (25) are slightly adjusted in play through a conical inner hole. The taper of the spindle inner hole is 1:

12. The inner ring is axially moved to make it expand and deform radially, so that the radial rigidity and preload can be adjusted. The front bearing spacer ring A (22), the front bearing spacer ring B (18), the rear bearing spacer ring C (26) and the rear bearing spacer ring D (24) are all designed with a water retaining ring and a labyrinth dustproof structure to prevent dust, cuttings and other particles generated during the turning process from damaging and contaminating the inside of the spindle.

7. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The front end cover (5) and the rear end cover (6) are provided with labyrinth grooves, which cooperate with the labyrinth grooves of the front bearing spacer ring A (22) and the rear bearing spacer ring D (24) to form a labyrinth structure. The rear end cover (6) is mounted on the rear end mounting cavity of the body assembly (2). The front end cover (5) is provided with an annular confluence groove and a plurality of discharge holes.

8. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The motor housing assembly (7) is detachably mounted on the mounting cavity at the rear end of the body assembly (2) and is fastened by screws. The motor housing assembly (7) comprises a motor housing (28) and a plurality of cooling medium connectors (27). The motor housing (28) is integrally cast and has a cooling medium flow channel designed therein. After being assembled with the stator assembly (8), a complete circulating water cooling system is formed. A plurality of cooling medium connector screw ports, a power line interface, an encoder line interface and an encoder mounting position are arranged on the outside of the motor housing (28).

9. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The encoder assembly (9) comprises a hollow magnetic ring (32) arranged on the outer circle of the rotor seat, an encoder head (33) arranged on the motor housing (28), and an encoder head bracket (34). The hollow magnetic ring (32) is provided with a plurality of countersunk holes for fixing and the outer circle of the hollow magnetic ring (32) is provided with a zero point. The rear end cylinder flange (10) of the hollow magnetic ring (32) is of a detachable design. After the cylinder flange is removed, the hollow magnetic ring (32) can be debugged at any time according to different client requirements, which also facilitates subsequent maintenance work. The encoder head (33) is fastened to the encoder head bracket (34) by screws. The encoder head bracket (34) is provided with a plurality of waist-shaped holes for adjusting the sensing distance between the encoder head (33) and the encoder magnetic ring (32) during assembly.

10. The rear motor spindle of a CNC lathe according to claim 1, characterized in that: The oil cylinder flange (10) is provided with a threaded hole for connecting to the oil cylinder, the shaft core (11) is provided with a shaft core inner hole through which a connecting rod can pass through a claw, and the oil cylinder flange (10) is locked to the rear end of the shaft core by a locking nut, and the rotor seat (13) is locked at the same time.

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