Grinding rod structure for grinding internal threads with large length-diameter ratio

Abstract

The utility model provides a grinding rod structure for grinding an internal thread with a large length-diameter ratio, and relates to the technical field of machining equipment. The grinding rod structure comprises a grinding rod body, a base, a turning piece, a grinding assembly, a flexible shaft and a nut. A grinding assembly is arranged on a throttling section of a turning part in a clearance sleeving mode, a fluid cavity is formed between the grinding assembly and the turning part, an annular first dynamic pressure oil groove is formed in the periphery of the throttling section, and an annular second dynamic pressure oil groove is formed in the end face of the grinding assembly. When the grinding assembly does not rotate, due to the fact that fluid has certain pressure at the moment, the grinding assembly can float to be separated from the direction changing piece. During machining, the grinding assembly rotates at a high speed, based on the first dynamic pressure oil groove and the second dynamic pressure oil groove, fluid in the fluid cavity has an obvious dynamic pressure effect, fluid pressure far larger than external pressure can be generated, the rigidity of the bearing is remarkably improved, abrasion is avoided, and the service life is long; and meanwhile, the structural form almost does not generate overturning moment, and the machining precision can be remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of machining equipment technology, and in particular to a grinding rod structure for grinding internal threads with a large length-to-diameter ratio. Background Technology

[0002] When grinding small-hole, large-lead internal threads, due to the existence of the thread helix angle, in order to avoid interference between the grinding rod and the workpiece, the bent rod grinding method is generally adopted. By mounting the grinding tool on the bent rod, the special shape and operability of the bent rod allow the grinding tool to penetrate deep into the thread for grinding.

[0003] The typical structure used is a bent rod with a flexible shaft and miniature bearings. Specifically, the flexible shaft connects the grinding wheel shaft and the main shaft at a certain angle. The flexible shaft is used to transmit power, and the grinding wheel shaft is used to drive the grinding wheel to rotate. The grinding wheel shaft is supported by miniature rolling bearings.

[0004] Due to spatial constraints, the bearings and flexible shaft of the grinding wheel spindle must be very small in size, while simultaneously operating under high speed and high load conditions. This results in insufficient bearing rigidity, making the bearings prone to wear and failure under high speed and high load conditions, leading to a short lifespan. Furthermore, because the miniature bearings have very low rigidity, vibrations during grinding, fluctuations in grinding depth, and feed rate significantly impact the final machining result, causing low machining accuracy of internal threads. Therefore, this type of grinding rod structure severely restricts the machining accuracy and efficiency of internal thread grinding. Utility Model Content

[0005] To address the shortcomings of existing bearing technology, such as insufficient rigidity leading to easy wear and failure under high-speed, high-load conditions and short lifespan, and the significant impact of vibration, grinding depth, and feed rate fluctuations during grinding on the final machining results due to the very low rigidity of miniature bearings, resulting in low machining accuracy of internal threads, this invention provides a grinding rod structure for grinding internal threads with large length-to-diameter ratios. The technical solution is as follows:

[0006] A grinding rod structure for grinding internal threads with a large length-to-diameter ratio is provided, the grinding rod structure comprising:

[0007] Grinding rod body;

[0008] A base is mounted on the grinding rod body, and the base has a liquid inlet channel inside;

[0009] A reversing component is connected to the base at a preset angle. The middle part of the reversing component includes a throttling section. The reversing component is provided with a throttling channel that communicates with the liquid inlet channel. The throttling orifice of the throttling channel is provided in the throttling section. An annular first dynamic pressure oil groove is provided on the outer periphery of the throttling section.

[0010] A grinding assembly, wherein the grinding assembly is fitted onto the throttling section and forms a fluid chamber with the reversing member, the fluid chamber contains a fluid medium for supporting the grinding assembly, and an annular second dynamic pressure oil groove is provided on the end face of the grinding assembly;

[0011] A flexible shaft, which rotatably passes through the base and the reversing member, and extends axially along the base and the reversing member in sequence;

[0012] A nut is connected to the flexible shaft via a set screw. The rear end of the nut is connected to the front end face of the grinding assembly. The flexible shaft drives the grinding assembly to rotate via the nut.

[0013] Optionally, the first dynamic pressure oil groove corresponds to the throttling orifice of the throttling channel.

[0014] Optionally, the grinding assembly includes an outer rotor and a grinding wheel mounted on the outer rotor;

[0015] The outer rotor and the nut are used to secure the grinding wheel from both ends.

[0016] Optionally, the front diameter of the nut is smaller than the rear diameter, and the angle between the sidewall of the nut and the axial direction is greater than or equal to the preset angle.

[0017] Optionally, the inner wall of the nut is provided with an annular groove.

[0018] Optionally, the base is provided with an eccentric hole, and the front end of the base is provided with an oblique hole at a preset angle to the eccentric hole. The eccentric hole and the oblique hole are connected to each other and are used to accommodate the flexible shaft.

[0019] Optionally, a fixing groove is formed at the end of the oblique hole;

[0020] The steering component includes an inner bushing, a bearing shell, and a thrust plate;

[0021] The inner bushing is interference-fitted into the fixing groove, and the bearing bush is interference-fitted onto the inner bushing, forming the throttling channel between the inner bushing and the bearing bush;

[0022] The thrust plate is fitted onto the front end of the inner bushing and presses against the bearing shell. The thrust plate and the bearing shell are used to limit the grinding assembly from both ends.

[0023] Optionally, an annular flow groove is provided on the front end face of the inner liner, and a through hole is provided on the upper part of the inner liner to connect the flow groove and the liquid inlet channel.

[0024] The contact surface between the inner bushing and the bearing bush is also provided with a flow channel connecting the flow groove and the throttling hole, and the through hole, the flow groove, the flow channel and the throttling hole form the throttling channel;

[0025] The number of throttling orifices is at least one pair.

[0026] Optionally, the liquid inlet hole corresponding to the liquid inlet channel is located on the side of the base.

[0027] Optionally, the size of the liquid inlet channel gradually decreases from the liquid inlet hole inwards.

[0028] The beneficial effects of the technical solution provided by this utility model embodiment include at least the following:

[0029] This invention provides a grinding rod structure for grinding internal threads with a large length-to-diameter ratio. The grinding assembly is fitted onto the throttling section of a reversing component, forming a fluid chamber between them. The throttling section has an annular first dynamic pressure oil groove on its outer periphery, and the grinding assembly has an annular second dynamic pressure oil groove on its end face. When the grinding assembly is not rotating, the fluid pressure allows it to float and detach from the reversing component, but its rigidity is determined by the external fluid pressure. During machining, the grinding assembly rotates at high speed. Based on the first and second dynamic pressure oil grooves, the fluid in the fluid chamber experiences significant dynamic pressure, generating a fluid pressure much greater than the external pressure. This significantly improves bearing rigidity, reduces wear, and extends service life. Furthermore, this structure generates almost no overturning moment and significantly improves machining accuracy. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided by an embodiment of this utility model;

[0032] Figure 2 This is a partial structural diagram of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided by an embodiment of this utility model.

[0033] Figure 3 This is a schematic diagram of the intermediate direction changing component and grinding assembly of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided by an embodiment of this utility model.

[0034] Figure label:

[0035] 1. Base; 11. Liquid inlet channel; 12. Eccentric hole; 13. Angled hole; 14. Fixing groove; 15. Liquid inlet hole;

[0036] 2. Reversing component; 21. Throttling channel; 211. Throttling orifice; 212. Flow groove; 213. Through hole; 214. Drainage channel; 22. First dynamic pressure oil groove; 23. Inner bushing; 24. Bearing shell; 25. Thrust plate;

[0037] 3. Grinding assembly; 31. Second hydrostatic oil tank; 32. Outer rotor; 33. Grinding wheel;

[0038] 4. Fluid chamber;

[0039] 5. Flexible shaft;

[0040] 6. Nut; 61. Set screw. Detailed Implementation

[0041] The technical solution of this utility model will now be described with reference to the accompanying drawings.

[0042] In the embodiments of this utility model, words such as "exemplarily" and "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in this utility model should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in the embodiments of this utility model, the meaning expressed by "and / or" can be both, or it can be either one or the other.

[0043] To make the technical problems, technical solutions and advantages of this utility model clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0044] This utility model embodiment provides a grinding rod structure for grinding internal threads with a large length-to-diameter ratio. Figure 1 This is a schematic diagram of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided by an embodiment of this utility model. Please refer to [the diagram]. Figure 1 .

[0045] The grinding rod structure includes: a grinding rod body (not shown in the figure), a base 1, a reversing component 2, a grinding assembly 3, a flexible shaft 5, and a nut 6. Through this grinding rod structure, the grinding assembly 3 is inserted into the threaded hole to grind the internal thread, matching the thread helix angle.

[0046] The aforementioned grinding rod body may or may not include a spindle. The grinding rod body is used to provide power and fluid medium, etc.

[0047] The base 1 is mounted on the grinding rod body via its rear end, and a liquid inlet channel 11 is provided inside the base 1. The front end of the base 1 can be formed into a long rod-like structure for easy partial insertion into the screw hole. The liquid inlet channel 11 is used to supply fluid to the throttling channel 21. Specifically, the fluid has a certain pressure to ensure the provision of a certain dynamic and static pressure.

[0048] The deflector 2 is connected to the base 1 at a preset angle. Specifically, this preset angle can be set as needed. The middle part of the deflector 2 includes a throttling section. The deflector 2 is provided with a throttling channel 21 that communicates with the liquid inlet channel 11. The throttling orifice 211 of the throttling channel 21 is located in the throttling section. That is to say, the throttling orifice 211 is arranged from the inside to the outside and is used to guide the fluid medium to flow out of the deflector 2. When the external pressure oil passes through the throttling orifice 211, a pressure drop is generated due to the reduction of the flow area, forming a stable static pressure oil film, which lifts the shaft and initially supports the load.

[0049] and, Figure 2 This is a partial structural diagram of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided by an embodiment of this utility model. Figure 3 This is a schematic diagram of the reversing component and grinding assembly of a grinding rod structure for grinding internal threads with a large length-to-diameter ratio, provided in an embodiment of this utility model. Please refer to [the diagram]. Figures 2 to 3 The outer periphery of the throttling section is provided with an annular first dynamic pressure oil groove 22. Specifically, when the grinding assembly 3 rotates, the fluid between its surface and the reversing member 2 is dragged by viscosity and flows at high speed along the tangential direction of the first dynamic pressure oil groove 22. The type of the first dynamic pressure oil groove 22 is not limited to stepped grooves, spiral grooves, herringbone grooves, or tilting pads that rely on the wedge principle to generate dynamic pressure. Based on this structure, the fluid is squeezed in the converging gap, and according to the Reynolds equation, the increased flow velocity leads to a sharp increase in fluid dynamic pressure. Finally, a dynamic pressure oil film is formed in the radial gap between the reversing member 2 and the grinding assembly 3, with a pressure much higher than the external static pressure, significantly improving the radial load-bearing capacity and supporting the weight and radial load of the grinding assembly 3.

[0050] The grinding assembly 3 is fitted onto the throttling section with a clearance, meaning that the grinding assembly 3 is installed without contact with the throttling section. This creates a fluid chamber 4 between the grinding assembly 3 and the deflector 2. The throttling section guides the fluid medium into the fluid chamber 4 and adjusts the flow rate and pressure of the fluid medium through its inner diameter, thereby accommodating the fluid medium in the fluid chamber 4 to support the grinding assembly 3. The fluid medium is not limited to liquid media such as water or hydraulic oil, or gaseous media such as air or nitrogen. An annular second dynamic pressure oil groove 31 is provided on the end face of the grinding assembly 3. The type of the first dynamic pressure oil groove 22 is not limited to stepped grooves, spiral grooves, herringbone grooves, or tilting pads that rely on the wedge principle to generate dynamic pressure. The second dynamic pressure oil groove 31 on the end face of the grinding assembly 3 generates centrifugal force with rotation, throwing the fluid radially out and forming an axial dynamic pressure oil film within the gap between the deflector 2 and the end face of the grinding assembly 3. The shape of the oil groove (such as a spiral groove) guides the fluid to generate circumferential flow, forming a pressure wedge in the convergence gap to counteract axial loads (such as axial thrust of the fluid or axial movement of the rotor) and prevent the direction changer 2 from directly contacting the end face of the grinding assembly 3.

[0051] The flexible shaft 5 rotatably passes through the base 1 and the reversing member 2, and extends axially along the base 1 and the reversing member 2 in sequence. The flexible shaft 5 can be connected to the main shaft for transmitting power, or it can be directly connected to the motor. This embodiment does not limit this.

[0052] Nut 6 is connected to flexible shaft 5 by set screw 61. The rear end of nut 6 is connected to the front end of grinding assembly 3. Based on this structure, flexible shaft 5 drives grinding assembly 3 to rotate through nut 6, and nut 6 plays the role of power transmission.

[0053] The reversing element 2 in the above structure forms an external grinding assembly 3 hydrostatic bearing. Specifically, the reversing element 2 is equivalent to the inner ring of the bearing, the fluid medium in the fluid chamber 4 is equivalent to the rolling element, and the grinding assembly 3 is equivalent to the outer ring of the bearing.

[0054] A fluid with a certain pressure flows in through the inlet channel 11 on the base 1, flows through the deflector 2, and flows out through the throttling orifice 211, finally entering the fluid chamber 4. When the grinding assembly 3 is not rotating, the fluid has a certain pressure, which can lift the grinding assembly 3 away from the deflector 2, but its rigidity is determined by the external fluid pressure. During processing, the grinding assembly 3 rotates at high speed. A first dynamic pressure oil groove 22 is provided on the outer circle of the throttling section, and a second dynamic pressure oil groove 31 is provided on the end face of the grinding assembly 3. The fluid in the fluid chamber 4 has a significant dynamic pressure effect, which can generate a fluid pressure much greater than the external pressure, thereby significantly improving the bearing rigidity. At the same time, since the grinding assembly 3 is not cantilevered like the grinding wheel 33 in the traditional bent bar structure, the bearing needs to withstand the overturning moment. The dynamic and static pressure bearing structure of this external grinding assembly 3 hardly generates an overturning moment, which is very beneficial for improving the machining accuracy.

[0055] The grinding rod structure for grinding internal threads with a large length-to-diameter ratio provided by this utility model involves fitting the grinding assembly 3 onto the throttling section of the reversing member 2 with a clearance, forming a fluid chamber 4 between them. The outer periphery of the throttling section is provided with an annular first dynamic pressure oil groove 22, and the end face of the grinding assembly 3 is provided with an annular second dynamic pressure oil groove 31. When the grinding assembly 3 is not rotating, the fluid has a certain pressure, which can lift the grinding assembly 3 away from the reversing member 2, but its rigidity is determined by the external fluid pressure. During processing, the grinding assembly 3 rotates at high speed. Based on the first and second dynamic pressure oil grooves 22 and 31, the fluid in the fluid chamber 4 has a significant dynamic pressure effect, generating a fluid pressure much greater than the external pressure, thereby significantly improving bearing rigidity, eliminating wear, and extending service life. Simultaneously, this structural form generates almost no overturning moment and can significantly improve machining accuracy.

[0056] In one embodiment of this utility model, the first dynamic pressure oil groove 22 corresponds to the throttling orifice 211 of the throttling channel 21. That is, the first dynamic pressure oil groove 22 and the throttling orifice 211 are aligned or connected in space. The fluid medium flowing out of the throttling orifice 211 can directly enter the first dynamic pressure oil groove 22, and form a superposition with the dynamic pressure effect to improve the dynamic pressure effect.

[0057] In one embodiment of this utility model, the grinding assembly 3 includes an outer rotor 32 and a grinding wheel 33 mounted on the outer rotor 32. The outer rotor 32 and a nut 6 are used to fix the grinding wheel 33 from both ends. Specifically, the nut 6 is threadedly connected to the outer rotor 32, and the nut 6 fixes the grinding wheel 33 from the front end. The rear end of the outer rotor 32 is widened to form a boss to fix the grinding wheel 33. The two form an axial clamping force to prevent the grinding wheel 33 from moving along the axial direction when rotating at high speed. Reliable positioning and stable transmission are achieved through mechanical clamping.

[0058] Based on the detachable structure of the outer rotor 32 and the grinding wheel 33, the grinding wheel 33 can be quickly disassembled, making it easy to replace grinding wheels 33 with different grit sizes or shapes, thereby improving processing efficiency.

[0059] The above structure forms a hydrostatic bearing for an outer rotor 32. A pressurized fluid medium can flow out at a certain velocity from the gap between the outer rotor 32 and the reversing member 2. The pressurized fluid medium can also flow out at a certain velocity from the gap between the nut 6 and the flexible shaft 5.

[0060] In one embodiment of this invention, the front diameter of the nut 6 is smaller than the rear diameter, and the angle between the sidewall of the nut 6 and the axial direction is greater than or equal to a preset angle. This structure ensures that the nut 6 will not interfere with the internal thread when working with the grinding structure.

[0061] In one embodiment of this utility model, the inner wall of the nut 6 is provided with an annular groove, which can correspond to the deflector 2 to avoid interference with the deflector 2.

[0062] In one embodiment of this utility model, an eccentric hole 12 is provided inside the base 1, which allows space for the liquid inlet channel 11. By optimizing the spatial layout, the diameter of the long rod-shaped structure at the front end of the base 1 is avoided, which is beneficial for it to be inserted into the screw hole. The front end of the base 1 is provided with an oblique hole 13 at a preset angle to the eccentric hole 12. The eccentric hole 12 and the oblique hole 13 are connected to each other for accommodating the flexible shaft 5. The connection structure between the oblique hole 13 and the eccentric hole 12 can change the direction of the flexible shaft 5 within a limited space.

[0063] Furthermore, in one embodiment of the present invention, a fixing groove 14 is formed at the end of the oblique hole 13; the deflector 2 includes an inner bushing 23, a bearing shell 24, and a thrust plate 25; the inner bushing 23 is interference-fitted in the fixing groove 14, the bearing shell 24 is interference-fitted on the inner bushing 23, and a throttling channel 21 is formed between the inner bushing 23 and the bearing shell 24; the thrust plate 25 is fitted onto the front end of the inner bushing 23 and presses against the bearing shell 24, and the thrust plate 25 and the bearing shell 24 are used to limit the grinding assembly 3 from both ends.

[0064] Pressurized fluid enters the inner bushing 23 through the oblique hole 13, flows into the throttling channel 21 between the inner bushing 23 and the bearing 24, and enters the fluid chamber 4 after passing through the throttling orifice 211. When the outer rotor 32 is stationary, the fluid pressure floats it up, reducing contact friction with the bearing 24 and the thrust plate 25. When the outer rotor 32 rotates at high speed, the first dynamic pressure oil groove 22 on the outer circle of the bearing 24 and the second dynamic pressure oil groove 31 on the end face of the outer rotor 32 cause the fluid in the fluid chamber 4 to generate a dynamic pressure effect, which, combined with the static pressure, forms a strong fluid pressure that supports the outer rotor 32 and drives the grinding wheel 33 to work. The thrust plate 25 and the bearing 24 limit the grinding assembly 3 from both ends, ensuring its stable operation.

[0065] The throttling channel 21, combined with the hydrodynamic oil groove, achieves hydrodynamic and hydrostatic lubrication. Compared with a single lubrication method, it can provide stable support across the entire speed range, reduce wear, and extend service life. The fixed groove 14, inner bushing 23, and other components form a stable installation structure, which, together with the thrust plate 25 and bearing 24, limits the grinding assembly 3, improving the stability and accuracy of the grinding assembly 3 during operation. The oil film formed by fluid lubrication can buffer vibration and impact, reduce noise, improve the smoothness of equipment operation, and at the same time reduce dependence on external high-pressure oil supply systems, thus reducing energy consumption.

[0066] Furthermore, in one embodiment of this utility model, an annular flow groove 212 is provided on the front end face of the inner bushing 23, and a through hole 213 connecting the flow groove 212 and the liquid inlet channel 11 is provided on the upper surface of the inner bushing 23; a drainage channel 214 connecting the flow groove 212 and the throttling hole 211 is also provided on the contact surface between the inner bushing 23 and the bearing 24; the number of throttling holes 211 is at least one pair.

[0067] Pressurized fluid enters the inlet channel 11 through an external pipeline and flows into the annular flow groove 212 on the front end face via the through hole 213 on the inner bushing 23. The fluid in the flow groove 212 is diverted through the guide channel 214 to the throttling orifice 211 at the contact surface between the inner bushing 23 and the bearing bush 24. The annular flow groove 212 acts as a fluid distribution hub, ensuring uniform fluid flow into the throttling channel 21 through the symmetrically distributed guide channels 214 and throttling orifices 211, avoiding wear or vibration caused by uneven loading and extending component life. The flow groove 212, through hole 213, guide channel 214, and other structures are integrated into the inner bushing 23, eliminating the need for additional pipelines or complex seals, simplifying the assembly process, and reducing equipment size. The through hole 213, flow groove 212, guide channel 214, and throttling orifice 211 form the aforementioned throttling channel 21, which is integrated into the inner bushing 23, eliminating the need for additional pipelines or complex seals, simplifying the assembly process, and reducing equipment size.

[0068] In one embodiment of this utility model, the liquid inlet hole 15 corresponding to the liquid inlet channel 11 is provided on the side of the base 1, which facilitates the connection of external pipelines and spatial layout.

[0069] In one embodiment of this utility model, the size of the inlet channel 11 gradually decreases from the inlet hole 15 inwards. The inlet channel 11 adopts a tapered structure, utilizing the Venturi effect in fluid mechanics: on the one hand, fluid with a certain pressure flows into the inlet channel 11 from the inlet hole 15. As the cross-sectional area of ​​the channel gradually decreases, the fluid velocity increases, and some static pressure energy is converted into kinetic energy; on the other hand, when the fluid enters the downstream throttling hole 211 and throttling channel 21, due to the high flow velocity and large kinetic energy, a stable static pressure oil film can be established more quickly after the throttling effect, improving the response speed of the lubrication system.

[0070] The tapered structure accelerates fluid flow, shortening the time difference between fluid supply and pressure build-up. Especially during equipment startup, it allows for faster formation of an oil film to support the grinding assembly 3, reducing dry friction wear. During channel contraction, the increased fluid kinetic energy suppresses oil film instability caused by fluctuations in external fluid supply pressure. Utilizing fluid kinetic energy to assist pressure build-up reduces the demand on the external fluid supply pump's output pressure, making it suitable for lower-power pump stations and reducing energy consumption and equipment costs. The tapered channel ensures more uniform fluid flow, reducing eddies or cavitation caused by abrupt changes in cross-sectional area, thus improving fluid transmission stability. The tapered channel can accelerate fluid within a limited length without requiring additional pipeline extension, making it suitable for equipment with limited internal space in the base 1.

[0071] The grinding rod structure for grinding internal threads with a large length-to-diameter ratio provided by this utility model involves fitting the grinding assembly 3 onto the throttling section of the reversing member 2 with a clearance, forming a fluid chamber 4 between them. The outer periphery of the throttling section is provided with an annular first dynamic pressure oil groove 22, and the end face of the grinding assembly 3 is provided with an annular second dynamic pressure oil groove 31. When the grinding assembly 3 is not rotating, the fluid has a certain pressure, which can lift the grinding assembly 3 away from the reversing member 2, but its rigidity is determined by the external fluid pressure. During processing, the grinding assembly 3 rotates at high speed. Based on the first and second dynamic pressure oil grooves 22 and 31, the fluid in the fluid chamber 4 has a significant dynamic pressure effect, generating a fluid pressure much greater than the external pressure, thereby significantly improving bearing rigidity, eliminating wear, and extending service life. Simultaneously, this structural form generates almost no overturning moment and can significantly improve machining accuracy.

[0072] The bearing structure employs a hydrostatic pressure design, primarily relying on hydrostatic pressure to ensure bearing rigidity (eliminating the need for a complex high-pressure fluid supply system). Simultaneously, the damping of the high-rigidity fluid film effectively suppresses vibrations in the flexible shaft 5 transmission, significantly improving surface finish. The bearing utilizes an external rotor 32 structure, where the grinding reaction force of the grinding wheel 33 acts directly on the external rotor 32, resulting in no overturning moment, high overall rigidity, and high machining accuracy. This bearing exhibits no wear due to non-contact friction and has a long service life.

[0073] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0074] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0075] It should be understood that in the various embodiments of this utility model, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this utility model.

[0076] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A grinding bar structure for internal thread grinding of large length-diameter ratio, characterized by, The grinding rod structure includes: Grinding rod body; A base is mounted on the grinding rod body, and the base has a liquid inlet channel inside; A reversing component is connected to the base at a preset angle. The middle part of the reversing component includes a throttling section. The reversing component is provided with a throttling channel that communicates with the liquid inlet channel. The throttling orifice of the throttling channel is provided in the throttling section. An annular first dynamic pressure oil groove is provided on the outer periphery of the throttling section. A grinding assembly, wherein the grinding assembly is fitted onto the throttling section and forms a fluid chamber with the reversing member, the fluid chamber contains a fluid medium for supporting the grinding assembly, and an annular second dynamic pressure oil groove is provided on the end face of the grinding assembly; A flexible shaft, which rotatably passes through the base and the reversing member, and extends axially along the base and the reversing member in sequence; A nut is connected to the flexible shaft via a set screw. The rear end of the nut is connected to the front end face of the grinding assembly. The flexible shaft drives the grinding assembly to rotate via the nut.

2. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The first dynamic pressure oil groove corresponds to the throttling orifice of the throttling channel.

3. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The grinding assembly includes an outer rotor and a grinding wheel mounted on the outer rotor; The outer rotor and the nut are used to secure the grinding wheel from both ends.

4. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The front diameter of the nut is smaller than the rear diameter, and the angle between the sidewall of the nut and the axial direction is greater than or equal to the preset angle.

5. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The inner wall of the nut is provided with an annular groove.

6. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The base has an eccentric hole, and the front end of the base has an oblique hole at a preset angle to the eccentric hole. The eccentric hole and the oblique hole are connected and are used to accommodate the flexible shaft.

7. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 6, characterized in that, A fixing groove is formed at the end of the oblique hole; The steering component includes an inner bushing, a bearing shell, and a thrust plate; The inner bushing is interference-fitted into the fixing groove, and the bearing bush is interference-fitted onto the inner bushing, forming the throttling channel between the inner bushing and the bearing bush; The thrust plate is fitted onto the front end of the inner bushing and presses against the bearing shell. The thrust plate and the bearing shell are used to limit the grinding assembly from both ends.

8. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 7, characterized in that, The inner liner has an annular flow groove on its front end face and a through hole on its upper surface that connects the flow groove and the liquid inlet channel. The contact surface between the inner bushing and the bearing bush is also provided with a flow channel connecting the flow groove and the throttling hole, and the through hole, the flow groove, the flow channel and the throttling hole form the throttling channel; The number of throttling orifices is at least one pair.

9. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The liquid inlet hole corresponding to the liquid inlet channel is located on the side of the base.

10. The grinding rod structure for grinding internal threads with a large length-to-diameter ratio according to claim 1, characterized in that, The size of the liquid inlet channel gradually decreases from the liquid inlet hole inwards.

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