Workpiece spindle arrangement for a grinding machine

Abstract

The utility model relates to a workpiece shaft device suitable for grinding machine, including the casing, the rotor shaft is installed in the casing, the rotor shaft front end is fixed with the rotary table, is equipped with motor rotor on the rotor shaft, and the motor rotor is connected with the rotor shaft through motor rotor fixed flange, the casing is corresponded motor rotor and is provided with motor stator, the rotor shaft front end is connected with the casing through the first precision bearing, the rotor shaft rear end is arranged in the bearing seat, and the bearing seat is provided with the second precision bearing and third precision bearing, the waterproof cover is set up in the casing front end, the waterproof cover is provided with the first sealing ring between waterproof cover and rotary table, and the waterproof cover is provided with the second sealing ring between waterproof cover and casing, the bearing seat rear end is provided with the gland, and the rotor shaft end is fixed with the encoding wheel, thereby, completely solve the problem that the belt slips, the vibration is big, the rotation speed is limited and the coupling rotation speed is insufficient, and the rotary table rotation speed and power torque are improved obviously, can reduce the power loss, and adapt to the efficient grinding demand.

Description

Technical Field

[0001] This utility model relates to a workpiece shaft, and more particularly to a workpiece shaft device suitable for grinding machines. Background Technology

[0002] In the field of grinding, the workpiece spindle assembly, as the core component driving workpiece rotation, directly determines the grinding quality of the workpiece due to its rotational accuracy, driving efficiency, and service life. Traditional workpiece spindles often use belts or couplings for transmission, which suffers from limited speed, high vibration, and high power loss. To address this issue, existing technologies have begun exploring direct-drive motor solutions. For example, there is a dedicated grinding machine motor that uses a permanent magnet direct-drive motor structure, connecting the spindle and motor rotor through a tapered fit to reduce operating losses and improve efficiency. Simultaneously, there are also direct-drive two-axis linkage structures for external thread grinding machines, where the headstock spindle is directly driven by an internal torque motor, combined with a fully closed-loop control to simplify the mechanical structure and improve accuracy. However, these solutions still have room for optimization in terms of heat dissipation control during high-speed motor operation, precision support of the rotor shaft, and coordinated adaptation of the drive system, making it difficult to simultaneously meet the requirements of high speed, low vibration, and long service life. Furthermore, the rotational accuracy of the workpiece spindle depends on the rational design of the bearing support structure. Existing similar solutions require the use of traditional transmission methods such as synchronous pulleys, without designing a bearing preload adjustment structure specifically for the force characteristics of the direct-drive motor.

[0003] Furthermore, the large amount of dust and splashed cutting fluid generated during grinding operations can easily penetrate the interior of the workpiece shaft, leading to bearing corrosion and motor insulation failure. Therefore, sealing protection is crucial. Existing workpiece shafts cannot form a multi-layered protection system covering the front, middle, and rear ends. They also lack the sealing coordination between dynamic rotating parts and static connection parts. In particular, the isolation and protection effect between the motor cavity and bearing cavity of direct-drive workpiece shafts is limited, making it difficult to meet the long-term use requirements under harsh grinding conditions.

[0004] In view of the above-mentioned shortcomings, the designer has actively researched and innovated in order to create a workpiece shaft device suitable for grinding machines, making it more industrially valuable. Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a workpiece shaft device suitable for grinding machines.

[0006] This utility model discloses a workpiece shaft device suitable for grinding machines, comprising a housing, within which a rotor shaft is installed. A turntable is fixed to the front end of the rotor shaft, and a motor rotor is mounted on the rotor shaft, connected to the rotor shaft via a motor rotor fixing flange. A motor stator is disposed within the housing corresponding to the motor rotor. The front end of the rotor shaft is connected to the housing via a first precision bearing, and the rear end of the rotor shaft passes through a bearing housing containing a second and a third precision bearing. A waterproof cover is provided at the front end of the housing, with a first sealing ring between the waterproof cover and the turntable, and a second sealing ring between the waterproof cover and the housing. A gland is provided at the rear end of the bearing housing, and an encoder wheel is fixed to the end of the rotor shaft.

[0007] Furthermore, in the above-mentioned workpiece shaft device suitable for grinding machines, a motor water jacket is provided on the outer side of the motor stator, and a quick-connect fitting is installed on the motor water jacket. The motor water jacket is used to introduce coolant to cool the motor stator.

[0008] Furthermore, in the aforementioned workpiece shaft assembly for a grinding machine, the second precision bearing and the third precision bearing are back-to-back interlocking ball bearings used to withstand the radial and axial forces of the rotor shaft.

[0009] Furthermore, in the aforementioned workpiece shaft device suitable for grinding machines, a first bearing cover and a second bearing cover are installed inside the bearing housing. The first bearing cover is fixed to the bearing housing by a fixing block and a fifth screw, and the second bearing cover is fixed to the bearing housing by an eleventh screw, a fifth bolt, and a sixth bolt.

[0010] Furthermore, in the aforementioned workpiece shaft assembly suitable for grinding machines, the first precision bearing is a large contact angle thrust bearing used to withstand the axial force of the turntable and the workpiece.

[0011] Furthermore, in the aforementioned workpiece shaft assembly for a grinding machine, the gland is fixed to the rear end of the bearing housing by an eighth screw and a ninth screw, and a labyrinth seal structure is formed between the gland and the rotor shaft.

[0012] Furthermore, in the aforementioned workpiece shaft device suitable for grinding machines, the encoder wheel is fixed to the end of the rotor shaft via an encoder wheel fixing flange and a thirtieth screw. The encoder wheel is used to cooperate with an external speed detection device to detect the speed and position of the rotor shaft.

[0013] Furthermore, in the aforementioned workpiece shaft device suitable for grinding machines, a fourth sealing ring is installed between the bearing housing and the housing, and the bearing housing is fixed to the rear end of the housing by a first bolt and a second bolt.

[0014] Furthermore, in the aforementioned workpiece shaft device suitable for grinding machines, the motor rotor is connected to the motor rotor fixing flange via the eighteenth and nineteenth screws.

[0015] Furthermore, in the aforementioned workpiece shaft device suitable for grinding machines, the rotary table is fixed to the front end of the rotor shaft by a first screw, and a mounting flange is fixed to the rear end of the housing by a sixth screw.

[0016] By means of the above solution, this utility model has at least the following advantages: 1. The housing is made of high-strength cast iron that has undergone aging treatment, effectively eliminating internal stress and preventing deformation under grinding vibration. This provides a precise and stable mounting reference for internal components. The rotor shaft is made of alloy structural steel and undergoes quenching and tempering followed by surface hardening. It possesses both high strength to withstand grinding axial and radial forces and high wear resistance against journal wear and bending deformation. Furthermore, the entire device is fixed in place via a mounting flange that matches the grinding machine bed interface, preventing shaking during grinding operations. This structural design ensures rotor shaft rotation accuracy and reduces grinding errors caused by component deformation or device displacement.

[0017] 2. Replacing traditional belt or coupling drives with direct motor drive completely solves the problems of belt slippage, excessive vibration, limited speed, and insufficient coupling speed, significantly improving turntable speed and power torque. It also reduces power loss and is suitable for high-efficiency grinding requirements. To address the issue of high-speed motor overheating, a water jacket with spiral cooling channels is installed on the outside of the motor stator. Connected to an external system via a quick-connect coupling, a 5% ethylene glycol aqueous solution circulates, keeping the motor stator temperature below 60℃. This prevents insulation aging and magnetic performance degradation caused by high temperatures, ensuring long-term stable motor output.

[0018] 3. The front end uses the first and second sealing rings to prevent seepage through gaps, while the middle end uses the fourth sealing ring (shaft) to isolate impurities from the connection seam. The rear end forms a labyrinth seal, forcing dust and cutting fluid to change their flow direction multiple times and overcome channel resistance, preventing them from penetrating the interior. This avoids corrosion of core components such as bearings and motors by impurities, significantly improving component reliability and the overall service life of the device.

[0019] 4. The front-end large contact angle thrust bearing is specifically designed to withstand the axial force of the turntable and workpiece, while the rear-end back-to-back interlocking ball bearings simultaneously withstand radial and bidirectional axial forces. The preload is controlled by adjusting the tightness of the bearing caps. Meanwhile, the incremental photoelectric encoder wheel at the end of the rotor shaft rotates synchronously with the rotor shaft, generating pulse signals in conjunction with an external photoelectric sensor. These signals are transmitted to the control system to achieve closed-loop speed control, ensuring stable speed during grinding and effectively improving the surface grinding quality and machining consistency of the workpiece.

[0020] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the workpiece shaft device suitable for grinding machines.

[0022] The meanings of the labels in the figures are as follows.

[0023] 1. Turntable; 2. First screw; 3. First sealing ring; 4. Waterproof cover; 5. Second screw; 6. Second sealing ring; 7. Housing; 8. First precision bearing; 9. First bolt; 10. Second bolt; 11. Third sealing ring; 12. Motor water jacket; 13. Motor stator; 14. Motor rotor; 15. Fourth sealing ring; 16. Bearing housing; 17. Motor rotor fixing flange; 18. Third screw; 19. Fourth screw; 20. Quick connector; 21. Second precision bearing; 22. Third precision bearing; 23. First bearing cover; 24. Fixing block; 25. Fifth screw; 26. Mounting flange; 27. Sixth screw; 28. Encoder wheel fixing flange; 29. ​​Encoder wheel; 30. Seventh screw; 31. Gland head; 32. Eighth screw; 33. Ninth screw; 34. Rotor shaft; 35. Third bolt; 36. Fourth bolt; 37. Tenth screw; 38. Second bearing cover; 39. Eleventh screw; 40. Fifth bolt; 41. Sixth bolt. Detailed Implementation

[0024] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0025] like Figure 1The workpiece shaft assembly for grinding machines includes a housing 7, which can be made of high-strength cast iron and undergoes aging treatment to eliminate internal stress, ensuring that it is not easily deformed under the vibration environment of grinding operations and providing a stable mounting reference for internal components. Its unique feature is that the housing 7 has a through-hole along the axial direction for mounting the rotor shaft 34. The rotor shaft 34 is the rotating core of the assembly, made of alloy structural steel, and undergoes tempering and surface hardening treatment, possessing both high strength and high wear resistance. It can withstand axial and radial forces during grinding, preventing journal wear or bending deformation after long-term use. Simultaneously, a turntable 1 is fixed to the shoulder at the front end of the rotor shaft 34 by a first screw 2. Specifically, the turntable 1 has a positioning hole at its center that matches the journal at the front end of the rotor shaft 34. During assembly, the turntable 1 is first press-fitted to the journal at the front end of the rotor shaft 34 through the positioning hole to achieve radial positioning. Subsequently, the turntable 1 is secured to the front end face of the rotor shaft 34 using 3-4 first screws 2 evenly distributed along the circumference of the turntable 1, ensuring no relative rotation between the turntable 1 and the rotor shaft 34. The upper end face of the turntable 1 is the workpiece clamping surface, with T-slots or locating pin holes for clamping the workpiece to be ground, ensuring that the workpiece rotates synchronously with the turntable 1 and avoiding surface quality defects caused by workpiece loosening during grinding. Furthermore, a mounting flange 26 is fixed to the flange face at the rear end of the housing 7 using a sixth screw 27. The external dimensions of the mounting flange 26 are adapted to the mounting interface of the grinding machine bed, and it has several evenly distributed mounting holes around its circumference. During assembly, the entire workpiece shaft assembly is fixed to the designated mounting position on the grinding machine using the mounting flange 26, ensuring the overall stability of the assembly during grinding operations and preventing the rotational accuracy of the rotor shaft 34 from being affected by overall wobbling of the assembly.

[0026] This device uses a direct-drive motor to replace traditional belt or coupling drives. It includes a motor stator 13, a motor rotor 14, and a motor rotor mounting flange 17, aiming to solve the problems of low speed, high vibration, and high power loss associated with traditional drive methods. Specifically, the motor rotor 14 is fitted onto the middle journal of the rotor shaft 34, ensuring that it is stably mounted on the rotor shaft 34 without radial movement. Axial positioning and fixing of the motor rotor 14 are achieved through the motor rotor mounting flange 17. During assembly, the motor rotor mounting flange 17 is divided into left and right parts, which are respectively fitted onto the two journals of the motor rotor 14. The eighteenth screw 18 and the nineteenth screw 19 are used to fasten the motor rotor mounting flange 17 to the end faces of the motor rotor 14. Simultaneously, the inner hole of the motor rotor mounting flange 17 is connected to the middle journal of the rotor shaft 34 via a 6×16 keyway, achieving circumferential fixing between the motor rotor mounting flange 17 and the rotor shaft 34, ultimately ensuring synchronous rotation of the motor rotor 14 and the rotor shaft 34 without relative slippage.

[0027] Further, corresponding radially to the motor rotor 14, a motor stator 13 is fixed in the middle section of the housing 7. The outer circle of the motor stator 13 is interference-fitted with the inner hole of the housing 7 to prevent vibration of the motor stator 13 when energized. Simultaneously, the air gap between the motor stator 13 and the motor rotor 14 is controlled at 0.2-0.3mm to ensure that the rotating magnetic field generated by the motor stator 13 after energization can efficiently drive the motor rotor 14 to rotate, reducing magnetic losses. Furthermore, to address the heat generation problem of the motor stator 13 during high-speed operation, a motor water jacket 12 is fitted on the outer side of the motor stator 13. Specifically, the inner hole of the motor water jacket 12 is tightly fitted with the outer circle of the motor stator 13, and a spiral cooling channel is formed inside the water jacket. Two quick-connect fittings 20 (model PC8-02) are welded to the side of the motor water jacket 12, serving as the inlet and outlet respectively. After the quick-connect connector 20 is quickly connected to the external cooling system piping, the coolant, typically a 5% ethylene glycol aqueous solution, circulates within the spiral flow channel of the motor water jacket 12, carrying away the heat generated by the motor stator 13. This keeps the operating temperature of the motor stator 13 below 60°C, preventing aging of the motor insulation layer or degradation of magnetic properties due to high temperatures.

[0028] In practical implementation, this device ensures the rotational accuracy of the rotor shaft 34 through a dual-stage precision bearing support structure at the front and rear ends, meeting the requirements of radial runout ≤0.001mm and axial movement ≤0.002mm. It includes a first precision bearing 8, a second precision bearing 21, a third precision bearing 22, a bearing housing 16, a first bearing cap 23, and a second bearing cap 38. Specifically, the journal at the front end of the rotor shaft 34 is connected to the front bearing cavity of the housing 7 via the first precision bearing 8. The first precision bearing 8 is a large contact angle thrust bearing, whose main function is to withstand the axial force generated by the turntable 1 and the clamped workpiece. The inner ring of the first precision bearing 8 has an interference fit with the front journal of the rotor shaft 34, while the outer ring has a transition fit with the inner hole of the front bearing cavity of the housing 7. The axial positioning of the bearing is achieved through the shoulder at the front end of the rotor shaft 34 and the step in the front bearing cavity of the housing 7, ensuring that the first precision bearing 8 has no axial movement during operation and providing stable axial support for the turntable 1.

[0029] Meanwhile, the rear journal of the rotor shaft 34 passes through the bearing housing 16. The front flange of the bearing housing 16 is secured to the rear flange of the housing 7 by four bolts (M10×25, evenly distributed circumferentially) via first bolts 9 and second bolts 10, which are external hexagonal bolts, achieving a rigid connection between the bearing housing 16 and the housing 7. The internal cavity of the bearing housing 16 houses a second precision bearing 21 and a third precision bearing 22, both of which are cross-contact ball bearings arranged back-to-back with their outer rings facing each other. This allows the bearing housing 16 to simultaneously withstand the radial force of the rotor shaft 34 (maximum radial load capacity ≥25kN) and the bidirectional axial force (maximum bidirectional axial load capacity ≥15kN), while maintaining high rigidity. This effectively limits the radial runout of the rotor shaft 34, ensuring stability during high-speed rotation.

[0030] Furthermore, to prevent axial movement of the second precision bearing 21 and the third precision bearing 22 during operation, a first bearing cap 23 and a second bearing cap 38 are distributed inside the bearing housing 16. Specifically, the first bearing cap 23 is located at the front end of the third precision bearing 22, near the motor side, and is fixed by a fixing block 24 and a fifth screw 25. The fixing block 24 has an arc-shaped structure that fits into the inner hole of the bearing housing 16, and can be fixed to the inner wall step of the bearing housing 16 by two fifth screws 25. At the same time, the front end face of the first bearing cap 23 fits against the rear end face of the fixing block 24, thereby axially limiting the outer ring of the third precision bearing 22. Meanwhile, a second bearing cap 38 is installed at the rear end of the second precision bearing 21. It can be fixed by an eleventh screw 39, a fifth bolt 40, and a sixth bolt 41. Considering the stability of the connection, the eleventh screw 39 can be a countersunk head hexagonal screw, model M4×6, with 3 screws evenly distributed circumferentially, used for the initial positioning of the second bearing cap 38 and the rear end face of the bearing housing 16. The fifth bolt 40 and the sixth bolt 41 are external hexagonal bolts, model M8×20, with 2 screws symmetrically distributed, used for the rigid fastening of the second bearing cap 38 and the bearing housing 16. The front end face of the second bearing cap 38 fits against the rear end face of the outer ring of the second precision bearing 21, achieving axial limiting of the outer ring of the second precision bearing 21. During assembly, the preload of the second precision bearing 21 and the third precision bearing 22 needs to be controlled within a suitable range by adjusting the tightening force of the first bearing cap 23 and the second bearing cap 38 to ensure that the bearings have no play during high-speed rotation, while avoiding excessive preload that could lead to increased bearing overheating.

[0031] To address the challenges of grinding machine operation, which involves significant dust and fluid splashing, this invention employs a multi-layered protective structure consisting of a front-end static seal, a middle-end static seal, and a rear-end labyrinth seal. This structure includes a waterproof cover 4, a first sealing ring 3, a second sealing ring 6, a fourth sealing ring 15, and a gland 31. The aim is to completely prevent dust and fluid from entering the device, protecting bearings and motor components and extending their service life. Specifically, the waterproof cover 4 is fixed to the front face of the housing 7 via bolts, sharing a mounting hole with the first screw 2. The waterproof cover 4 has an annular structure with an inner diameter slightly larger than the outer diameter of the turntable 1, with a gap controlled at 0.5-1mm to prevent friction between the turntable 1 and the waterproof cover 4 during rotation. Simultaneously, a first sealing ring 3, preferably made of fluororubber, is positioned at the radial gap between the waterproof cover 4 and the turntable 1. This first sealing ring 3 is embedded in an annular groove on the inner wall of the waterproof cover 4, allowing it to fit tightly against the outer surface of the turntable 1, forming the first static seal and preventing fluid from seeping in through the gap between the turntable 1 and the waterproof cover 4.

[0032] Furthermore, this invention also includes a second sealing ring 6 distributed between the waterproof cover 4 and the front end face of the housing 7. This second sealing ring 6 is embedded in the annular groove on the front end face of the housing 7. It can fit tightly against the rear end face of the waterproof cover 4, forming a second static seal to prevent dust and cutting fluid from seeping in from the connection seam between the waterproof cover 4 and the housing 7. A fourth sealing ring 15, made of nitrile rubber O-ring, is provided between the front flange face of the bearing housing 16 and the rear flange face of the housing 7. This fourth sealing ring 15 is embedded in the annular groove on the rear flange face of the housing 7, and can fit tightly against the front flange face of the bearing housing 16, forming a mid-section static seal to prevent dust and cutting fluid from seeping into the interior of the bearing housing 16 from the connection seam between the bearing housing 16 and the housing 7, thus protecting the second precision bearing 21 and the third precision bearing 22.

[0033] In actual assembly, a gland 31 is fixed to the rear center hole of the bearing housing 16 by the eighth screw 32 and the ninth screw 33. The inner hole of the gland 31 forms a labyrinth seal structure with the rear journal of the rotor shaft 34. Specifically, the inner wall of the gland 31 has 2-3 annular bosses, each 0.5mm high and 1mm wide. Simultaneously, the rear journal of the rotor shaft 34 has 2-3 corresponding annular grooves, each 0.5mm deep and 1mm wide. The bosses and grooves mesh with each other, forming a tortuous gap channel with a gap width of 0.1-0.2mm. When dust or cutting fluid attempts to seep into the gap between the gland 31 and the rotor shaft 34, it must repeatedly change its flow direction and overcome channel resistance, ultimately being blocked externally, forming a non-contact seal at the rear. Furthermore, the cable hole of the gland 31 is used to pass through the signal wire of the encoder wheel 29, achieving sealed protection for the signal wire and preventing dust from corroding the signal wire connector.

[0034] To achieve precise control of the rotational speed and position of the rotor shaft 34 and ensure stable rotational speed with fluctuations ≤±1% during grinding, an encoder wheel 29 and an encoder wheel fixing flange 28 are provided at the end of the rotor shaft 34. The encoder wheel 29 used in this invention is an incremental photoelectric encoder wheel, whose center hole is fixed to the end journal of the rotor shaft 34 via the encoder wheel fixing flange 28. Simultaneously, the inner hole of the encoder wheel fixing flange 28 and the end journal of the rotor shaft 34 have a transition fit with a tolerance of H7 / h6. Three countersunk hexagonal head screws (M4×8 type, evenly distributed circumferentially) are used to fasten the encoder wheel 29 to the end face of the encoder wheel fixing flange 28. The inner hole of the encoder wheel fixing flange 28 and the end journal of the rotor shaft 34 are connected by a flat key with a keyway specification of 4×8, achieving synchronous rotation of the encoder wheel 29 and the rotor shaft 34.

[0035] During actual implementation, the encoder wheel 29 is used in conjunction with an external speed detection device. An optional photoelectric sensor is available, with its transmitter and receiver located on opposite sides of the encoder wheel 29. When the encoder wheel 29 rotates, the light-transmitting holes and light-blocking areas on its edge alternately pass through the detection light path of the photoelectric sensor, generating pulse signals. These pulse signals are then transmitted via a signal cable through the cable hole of the gland 31 to the grinding machine's control system. The control system calculates the real-time speed of the rotor shaft 34 based on the frequency of the pulse signals and calculates the rotational position of the rotor shaft 34 based on the count of the pulse signals. Simultaneously, closed-loop control of the rotor shaft 34 speed can be achieved by adjusting the energizing frequency of the motor stator 13, ensuring that the speed remains stable at a set value during grinding, such as 500-3000 r / min, adjusted according to the workpiece material and grinding process.

[0036] Furthermore, the directions or positional relationships described in this utility model are based on the directions or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this utility model and simplifying the description, and are not intended to indicate or imply that the device or structure referred to must have a specific orientation, or to operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A workpiece shaft assembly suitable for a grinding machine, comprising a housing (7) in which a rotor shaft (34) is installed, characterized in that: A turntable (1) is fixed at the front end of the rotor shaft (34), and a motor rotor (14) is sleeved on the rotor shaft (34). The motor rotor (14) is connected to the rotor shaft (34) through a motor rotor fixing flange (17). The housing (7) is provided with a motor stator (13) corresponding to the motor rotor (14). The front end of the rotor shaft (34) is connected to the housing (7) through a first precision bearing (8). The rear end of the rotor shaft (34) passes through a bearing seat (16). The bearing seat (16) is provided with a second precision bearing (21) and a third precision bearing (22). A waterproof cover (4) is provided at the front end of the housing (7), a first sealing ring (3) is provided between the waterproof cover (4) and the turntable (1), and a second sealing ring (6) is provided between the waterproof cover (4) and the housing (7). The bearing housing (16) is provided with a gland head (31) at the rear end, and the rotor shaft (34) is fixed with an encoder wheel (29) at the end.

2. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The motor stator (13) is fitted with a motor water jacket (12) on the outside. A quick-connect connector (20) is installed on the motor water jacket (12). The motor water jacket (12) is used to introduce coolant to cool the motor stator (13).

3. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The second precision bearing (21) and the third precision bearing (22) are back-to-back interlocking ball bearings used to withstand the radial and axial forces of the rotor shaft (34).

4. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The bearing housing (16) is equipped with a first bearing cover (23) and a second bearing cover (38). The first bearing cover (23) is fixed to the bearing housing (16) by a fixing block (24) and a fifth screw (25). The second bearing cover (38) is fixed to the bearing housing (16) by an eleventh screw (39), a fifth bolt (40) and a sixth bolt (41).

5. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The first precision bearing (8) is a large contact angle thrust bearing used to bear the axial force of the turntable (1) and the workpiece.

6. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The gland head (31) is fixed to the rear end of the bearing housing (16) by the eighth screw (32) and the ninth screw (33), and a labyrinth seal structure is formed between the gland head (31) and the rotor shaft (34).

7. The workpiece shaft device for grinding machines according to claim 1, characterized in that: The encoder wheel (29) is fixed to the end of the rotor shaft (34) by the encoder wheel fixing flange (28) and the thirtieth screw (30). The encoder wheel (29) is used to cooperate with an external speed detection device to detect the speed and position of the rotor shaft (34).

8. The workpiece shaft device for grinding machines according to claim 1, characterized in that: A fourth sealing ring (15) is installed between the bearing seat (16) and the housing (7), and the bearing seat (16) is fixed to the rear end of the housing (7) by a first bolt (9) and a second bolt (10).

9. The workpiece shaft device for a grinding machine according to claim 1, characterized in that: The motor rotor (14) is connected to the motor rotor fixing flange (17) by the eighteenth screw (18) and the nineteenth screw (19).

10. The workpiece shaft device for a grinding machine according to claim 1, characterized in that: The turntable (1) is fixed to the front end of the rotor shaft (34) by the first screw (2), and the rear end of the housing (7) is fixed with a mounting flange (26), which is fixed by the sixth screw (27).

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