Main shaft structure of thread rolling machine

Abstract

The utility model discloses a thread rolling machine main shaft structure, especially in numerical control machine tool technical field, including main shaft body, main shaft seat, servo motor and worm gear reducer, the output of servo motor is connected with transmission shaft through flat key no.

Description

Technical Field

[0001] This utility model relates to the field of CNC machine tool technology, and more specifically, to the spindle structure of a thread rolling machine. Background Technology

[0002] Currently, thread rolling machines are widely used as an important processing equipment in the fields of rolling, knurling, and burnishing of worm gears, lead screws, and threaded parts. However, existing thread rolling machines, whether traditional mechanical-hydraulic, semi-servo-semi-hydraulic, or the sporadic fully CNC servo types, all have some room for improvement: Traditional mechanical hydraulic thread rolling machines are usually bulky and heavy, and the operation and debugging process is complicated and inconvenient. Although semi-servo semi-hydraulic equipment has achieved automation in some functions, its overall rolling accuracy is still difficult to meet the processing requirements of high-precision parts. In addition, existing equipment on the market generally suffers from unreasonable spindle structure design, which is mainly manifested in limited load-bearing capacity. When subjected to large rolling forces, it is prone to deformation or vibration, resulting in unstable processing accuracy. At the same time, key components such as bearings are easily damaged due to uneven load distribution or insufficient support, resulting in a short overall equipment life. Crucially, existing thread rolling machines mostly use planetary gear reducers as the core component of the transmission system. Under special working conditions, such as high-frequency forward and reverse rotation and long-term heavy-load operation, the transmission accuracy is poor and there is a certain backlash. It is difficult to meet the stringent requirements of high-precision repeated rolling process for spindle positioning accuracy and motion stability. In view of this, this utility model proposes a spindle structure for thread rolling machines. Utility Model Content

[0003] In order to overcome the above-mentioned defects of the prior art, the present invention provides a spindle structure for a thread rolling machine to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a thread rolling machine spindle structure, including a spindle body, a spindle seat, a servo motor, and a worm gear reducer. The output end of the servo motor is connected to a transmission shaft via a key, and the transmission shaft is connected to the input end of the worm gear reducer via a key. The output end of the worm gear reducer is connected to the input end of the spindle body via a keyway coupling. A bearing assembly for bearing radial and axial loads is installed inside the spindle seat, and an end support device for sharing the load is also provided at the extended end of the spindle body.

[0005] Preferably, the bearing assembly includes two pairs of single-row cylindrical roller bearings and one pair of single-row tapered roller bearings installed in the spindle housing. The two pairs of single-row cylindrical roller bearings are respectively a first single-row cylindrical roller bearing, a second single-row cylindrical roller bearing, a third single-row cylindrical roller bearing, and a fourth single-row cylindrical roller bearing. The one pair of single-row tapered roller bearings is a first single-row tapered roller bearing and a second single-row tapered roller bearing. These bearings, together with the bushing, are arranged sequentially along the axial direction of the spindle body.

[0006] Preferably, it also includes an adjusting ring for adjusting the axial position of the bearing and a spindle locking nut for locking the second single-row tapered roller bearing.

[0007] Preferably, the end support device includes a bracket and a double-row needle roller bearing. The double-row needle roller bearing is installed in the bracket, and its front and rear sides are respectively pressed and limited by a first end cap and a pressure ring, and then pressed by a pressure cap. The bracket is fixedly connected to the spindle seat by multiple external hexagonal bolts and corresponding T-nuts.

[0008] Preferably, a front cover is installed at the front end of the spindle seat, the front cover is fixed by a bolt, and a lip seal is provided on its inner side. The rear end of the spindle seat is pressed by a coupling sleeve and fixed by a bolt.

[0009] Preferably, the keyway coupling is connected to the input end of the main shaft via a flat key, and a limiting sleeve is provided between the coupling and the main shaft seat.

[0010] Preferably, the servo motor is connected to the housing of the worm gear reducer via bolt three, and bolt two is provided on the mounting base of the worm gear reducer to fix the entire reducer to the frame.

[0011] Preferably, the pressure cap is pressed onto the end of the bracket by bolt seven, and the bracket is also provided with bolt six and pin for auxiliary positioning and fixing.

[0012] The technical effects and advantages of this utility model are as follows: By adopting a power transmission scheme of servo motor and worm gear reducer, and with the keyway coupling and flat key connection, the power transmission is precisely controllable and highly reliable. The closed-loop control characteristics of the servo motor itself, combined with the single-stage large transmission ratio and possible reverse self-locking characteristics of the worm gear transmission pair, not only ensure the strong and stable output torque, but also enable the spindle to achieve precise speed and angle control, thereby directly improving the repeatability accuracy of the thread rolling machine and the ability to realize complex processes. By employing a combined support structure of multiple bearing assemblies within the spindle housing and independent end support devices on the spindle body, the overall rigidity and deformation resistance of the spindle system are greatly enhanced. The densely arranged cylindrical roller and tapered roller bearings within the spindle housing effectively distribute radial and axial loads, while the auxiliary support at the end, composed of double-row needle roller bearings, forms a stable two-point support structure with the main support, significantly suppressing the deflection deformation of the spindle overhang. This allows the spindle body to maintain extremely high operational stability even when subjected to heavy thread rolling forces, thereby simultaneously achieving improvements in high load-bearing capacity and long service life. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0014] Figure 2 This is an exploded view of the present invention.

[0015] Figure 3 This is an exploded view of the present invention from another angle.

[0016] Figure 4 This is an assembly structure diagram of the spindle body and spindle seat of this utility model.

[0017] Figure 5 This is a schematic diagram of the servo motor transmission structure of this utility model.

[0018] The attached figures are labeled as follows: 1. Main shaft; 2. Adjusting ring; 3. First single-row tapered roller bearing; 4-1. First single-row cylindrical roller bearing; 4-2. Second single-row cylindrical roller bearing; 5. Bushing; 6-1. Third single-row cylindrical roller bearing; 6-2. Fourth single-row cylindrical roller bearing; 7. Second single-row tapered roller bearing; 8. Main shaft lock nut; 9. Coupling; 10. Limit sleeve; 11. Bolt one; 12. Servo motor; 13. Bolt two; 4. Worm gear reducer; 15. Bolt 3; 17. Coupling sleeve; 18. Bolt 4; 20. Main shaft seat; 22. Front end cover; 23. Lip seal; 24. External hex bolt; 25. T-nut; 27. Pressure ring; 28. Bracket; 29. ​​Double row needle roller bearing; 30. First end cover; 31. Bolt 6; 32. Pressure cap; 33. Bolt 7; 34. Pin; 36. Key 1; 37. Key 2; 38. Key 3; 39. Drive shaft. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] As attached Figure 1-5 The thread rolling machine spindle structure shown includes a spindle body 1, a spindle seat 20, a servo motor 12, and a worm gear reducer 14. The output end of the servo motor 12 is connected to the transmission shaft 39 via a key 36. The transmission shaft 39 is connected to the input end of the worm gear reducer 14 via a key 37. The output end of the worm gear reducer 14 is connected to the input end of the spindle body 1 via a keyway coupling 9. The spindle seat 20 is equipped with a bearing assembly for bearing radial and axial loads. The extended end of the spindle body 1 is also provided with an end support device for sharing the load.

[0021] Specifically, in this structure, the servo motor 12 serves as the power source and achieves precise speed reduction and torque increase through the worm gear reducer 14, forming a high-precision and high-power drive core. The multiple bearing groups arranged in the spindle seat 20 serve as the core load-bearing unit, jointly bearing the radial and axial loads during operation. The independent support device set at the extended end of the spindle body 1 works in conjunction with the bearing groups in the spindle seat 20 to form a stable two-point support structure, which greatly enhances the overall rigidity of the spindle body 1 and effectively suppresses deformation and vibration during the machining process. Thus, they jointly achieve a comprehensive performance improvement of high load-bearing capacity, high transmission accuracy, and long service life.

[0022] In this embodiment, the bearing assembly includes two pairs of single-row cylindrical roller bearings and one pair of single-row tapered roller bearings installed in the spindle housing 20. The two pairs of single-row cylindrical roller bearings are a first single-row cylindrical roller bearing 4-1, a second single-row cylindrical roller bearing 4-2, a third single-row cylindrical roller bearing 6-1, and a fourth single-row cylindrical roller bearing 6-2, respectively. The pair of single-row tapered roller bearings are a first single-row tapered roller bearing 3 and a second single-row tapered roller bearing 7. These bearings are arranged sequentially along the axial direction of the spindle body 1 together with the bushing 5.

[0023] Specifically, in this structure, two pairs of single-row cylindrical roller bearings serve as the core radial support units. With their high radial load capacity and line contact advantages, they are symmetrically and densely distributed at both ends of the main shaft 1, jointly bearing most of the radial cutting force. A pair of single-row tapered roller bearings serve as a composite load-bearing unit. With their ability to withstand both radial and axial loads, they work in conjunction with cylindrical roller bearings to precisely define the axial position of the spindle body 1 and resist the axial thrust generated during machining. Each bearing is precisely positioned and spaced by bushing 5, forming a support system that is closely arranged and has a clear division of labor along the axis of the main shaft 1. This layout greatly enhances the overall rigidity, rotational accuracy and fatigue resistance of the main shaft components, fundamentally ensuring stable operation and long service life under high load thread rolling conditions.

[0024] In this embodiment, it also includes an adjusting ring 2 for adjusting the axial position of the bearing and a spindle locking nut 8 for locking the second single-row tapered roller bearing 7.

[0025] Specifically, in this structure, the adjusting ring 2 serves as a precision axial dimension compensation unit. Its precise thickness dimension is used to set the initial clearance or preload of the bearing assembly, ensuring that all bearings achieve uniform force and minimal vibration under optimal working conditions. The spindle locking nut 8 serves as the final axial locking unit. Through the constant locking torque it applies, it firmly locks the precisely adjusted bearing assembly position, effectively preventing accuracy decay caused by slight movement under high-speed alternating load conditions. This not only ensures the stability of the axial positioning accuracy of the spindle body 1 during long-term heavy-load operation, but also significantly improves the dynamic stiffness and impact resistance of the entire spindle system.

[0026] In this embodiment, the end support device includes a bracket 28 and a double-row needle roller bearing 29. The double-row needle roller bearing 29 is installed in the bracket 28, and its front and rear sides are respectively pressed and limited by the first end cover 30 and the pressure ring 27, and pressed by the pressure cover 32. The bracket 28 is fixedly connected to the spindle seat 20 by multiple external hexagonal bolts 24 and corresponding T-nuts 25.

[0027] Specifically, in this structure, the double-row needle roller bearing 29, with its compact radial structure and strong load-bearing capacity, provides crucial auxiliary radial support for the spindle overhang. The bracket 28, as the load-bearing skeleton, is rigidly connected to the spindle seat 20 through the external hexagonal bolts 24 and T-nuts 25, effectively transferring the end load to the main body. The first end cover 30 and the pressure ring 27 constitute a bidirectional axial constraint for the bearing, ensuring the positioning accuracy of the needle roller bearing during high-speed operation. Finally, the pressure cover 32 completes the axial clamping, forming a stable closed force system, which significantly enhances the spindle system's ability to resist bending deformation and effectively ensures the stability of machining accuracy and the service life of the equipment under heavy-load thread rolling conditions.

[0028] In this embodiment, a front cover 22 is installed at the front end of the spindle seat 20. The front cover 22 is fixed by bolt 11 and a lip seal 23 is provided on its inner side. The rear end of the spindle seat 20 is pressed by a coupling sleeve 17 and fixed by bolt 4 18.

[0029] Specifically, in this structure, the front cover 22 is reliably connected to the spindle seat 20 by bolt 11, and the lip seal 23 provided on its inner side forms a tight dynamic sealing interface with the surface of the spindle body 1, effectively preventing lubricant leakage and external contaminant intrusion. Meanwhile, the coupling sleeve 17 installed at the rear end of the spindle seat 20 achieves precise axial positioning and pre-tightening of the internal bearing assembly through the clamping force applied by the bolts 18, forming a stable rigid support. This ensures the lubrication stability, cleanliness maintenance, and axial positioning accuracy of the spindle body 1 under long-term high-speed operation conditions, thereby significantly improving the reliability and service life of the spindle system.

[0030] In this embodiment, the keyway coupling 9 is connected to the input end of the main shaft 1 via a flat key 38, and a limiting sleeve 10 is provided between the coupling 9 and the main shaft seat 20.

[0031] Specifically, in this structure, the keyway coupling 9 forms a rigid connection with the spindle body 1 without relative rotation via the flat key 38, ensuring accurate and reliable power transmission. The limiting sleeve 10, located between the coupling 9 and the spindle seat 20, serves as a precise positioning element. Its precise axial length not only limits the axial movement of the coupling 9 but also provides a stable axial mounting reference for the bearing assembly within the spindle seat 20. This not only achieves efficient transmission of high torque but also ensures the axial dimensional stability of the entire spindle system under high-speed and heavy-load conditions through mechanical limiting, effectively preventing accuracy loss and equipment damage caused by axial movement.

[0032] In this embodiment, the servo motor 12 is connected to the housing of the worm gear reducer 14 by bolt three 15, and bolt two 13 is provided on the mounting base of the worm gear reducer 14 to fix the entire reducer to the frame.

[0033] Specifically, in this structure, the servo motor 12 is rigidly connected to the housing of the worm gear reducer 14 via bolt three 15, ensuring precise alignment and structural integrity between the power input end and the reduction mechanism. At the same time, the entire transmission unit is firmly fixed to the frame by bolt two 13 on the reducer mounting base, effectively suppressing the reaction torque and vibration generated by the transmission system during start-up, shutdown, and reversal. This provides a stable working foundation for the worm gear transmission pair, ensuring the durability of transmission accuracy and improving the rigidity and stability of the entire machine by effectively distributing the equipment's working load to the frame.

[0034] In this embodiment, the pressure cap 32 is pressed onto the end of the bracket 28 by bolt 33. The bracket 28 is also provided with bolt 31 and pin 34 for auxiliary positioning and fixing.

[0035] Specifically, in this structure, the pressure cap 32, through the uniform clamping force provided by bolt 33, ensures that the double-row needle roller bearing 29 obtains stable axial constraint within the bracket 28, thereby effectively maintaining its working clearance and accuracy. At the same time, the pin 34 achieves precise positioning between the bracket 28 and the spindle seat 20 through interference fit, ensuring the coaxiality requirements of the mounting hole system of the two. Bolt 31, together with the aforementioned hexagonal bolt 24, forms multiple fastening guarantees, further enhancing the reliability of the bracket 28 connection, ensuring the structural stability of the end support device under alternating loads, enabling it to effectively and continuously share the load of the spindle overhang end, and ensuring the operating accuracy of the entire spindle system.

[0036] Working principle of this utility model: This application provides a spindle structure for a thread rolling machine. In practical use, the servo motor 12 serves as the core power source, receiving instructions from the CNC system and outputting precise and controllable rotational motion. This power is transmitted to the worm gear reducer 14 without slippage through the transmission shaft 39 connected by a key. The worm gear mechanism completes the key speed reduction and torque increase here, and finally reliably inputs the smooth and strong power to the spindle body 1 through the keyway coupling 9 and the key. Subsequently, the complex loads borne by the spindle body 1 during rotation are jointly borne by the carefully arranged bearing assembly inside the spindle housing 20 and the independent support device at the end. Inside the spindle housing 20, two pairs of single-row cylindrical roller bearings bear the main radial load with their high radial load capacity, while a pair of single-row tapered roller bearings are responsible for bearing the bidirectional axial force and precisely defining the axial position of the spindle. The optimal bearing clearance is set by the adjusting ring 2 and finally locked by the spindle locking nut 8, forming a rigid core support unit. At the same time, the spindle overhang end obtains key auxiliary radial support through the double-row needle roller bearing 29 on the bracket 28. This end support device works in conjunction with the bearing assembly inside the spindle housing 20 to form an effective two-point support structure, which greatly suppresses the bending deformation of the spindle body 1. Finally, the dynamic sealing interface formed by the front cover 22 and the lip seal 23 effectively keeps the inside of the spindle seat 20 lubricated and clean. The coupling sleeve 17 and the limit sleeve 10 together ensure the stability of the axial dimension of the spindle system. The servo motor 12 and the reducer, the reducer and the frame, and the bracket 28 and the spindle seat 20 are firmly connected and precisely positioned by various bolts and pins 34, ensuring the structural integrity and dynamic stability of the entire transmission system under high-speed and heavy-load conditions. The synergistic effect of all the above-mentioned technical features ultimately achieves a comprehensive improvement in the overall performance of the thread rolling machine spindle structure, including high load-bearing capacity, high precision, long service life, and reliable operation.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. The main shaft structure of a thread rolling machine, characterized in that: It includes a spindle body (1), a spindle seat (20), a servo motor (12), and a worm gear reducer (14). The output end of the servo motor (12) is connected to the drive shaft (39) via a key (36); The drive shaft (39) is connected to the input end of the worm gear reducer (14) via a key (37); The output end of the worm gear reducer (14) is connected to the input end of the main shaft (1) through a keyway coupling (9); The main spindle seat (20) is equipped with a bearing assembly for bearing radial and axial loads; The extended end of the main shaft (1) is also provided with an end support device for sharing the load.

2. The spindle structure of the thread rolling machine according to claim 1, characterized in that: The bearing assembly includes two pairs of single-row cylindrical roller bearings and one pair of single-row tapered roller bearings installed in the main shaft housing (20); The two pairs of single-row cylindrical roller bearings are the first single-row cylindrical roller bearing (4-1), the second single-row cylindrical roller bearing (4-2), the third single-row cylindrical roller bearing (6-1), and the fourth single-row cylindrical roller bearing (6-2). A pair of single-row tapered roller bearings are a first single-row tapered roller bearing (3) and a second single-row tapered roller bearing (7); These bearings, together with the bushings (5), are arranged sequentially along the axial direction of the main shaft (1).

3. The spindle structure of the thread rolling machine according to claim 2, characterized in that: It also includes an adjusting ring (2) for adjusting the axial position of the bearing and a spindle locking nut (8) for locking the second single-row tapered roller bearing (7).

4. The spindle structure of the thread rolling machine according to claim 1, characterized in that: The end support device includes a bracket (28) and a double-row needle roller bearing (29). The double-row needle roller bearing (29) is installed in the bracket (28), and its front and rear sides are respectively pressed and limited by the first end cover (30) and the pressure ring (27), and pressed by the pressure cover (32); The bracket (28) is fixedly connected to the spindle seat (20) by multiple external hexagonal bolts (24) and corresponding T-nuts (25).

5. The spindle structure of the thread rolling machine according to claim 1, characterized in that: The front end of the spindle seat (20) is fitted with a front end cover (22), which is fixed by bolt (11) and has a lip seal (23) on its inner side. The rear end of the main spindle seat (20) is pressed by a coupling sleeve (17) and fixed with bolts four (18).

6. The spindle structure of the thread rolling machine according to claim 1, characterized in that: The keyway coupling (9) is connected to the input end of the main shaft (1) via a flat key (38); A limiting sleeve (10) is provided between the coupling (9) and the main shaft seat (20).

7. The spindle structure of the thread rolling machine according to claim 1, characterized in that: The servo motor (12) is connected to the housing of the worm gear reducer (14) by bolt three (15); The mounting base of the worm gear reducer (14) is provided with bolt two (13) for fixing the entire reducer to the frame.

8. The spindle structure of the thread rolling machine according to claim 4, characterized in that: The pressure cap (32) is pressed into the end of the bracket (28) by bolt seven (33); The bracket (28) is also provided with six bolts (31) and pins (34) for auxiliary positioning and fixing.

Images