A grinding machine for ball screw nut

Abstract

The utility model relates to the technical field of machining, especially relates to a grinding rod for processing ball screw nut, including grinding rod main part, base, direction changer, grinding assembly, flexible axle and nut, the base is installed on the grinding rod main part, the base includes seat body, with the integral moulding axle body of seat body, still is equipped with the air supply channel in the axle body, the outer peripheral surface of base is horizontally provided with air inlet, air inlet communicates with the air supply channel, the fixed groove that axle body end portion is equipped with for the embedding of direction changer, the channel wall of fixed groove is all passed to the air supply channel and liquid inlet channel, the utility model has the advantages of: the static pressure bearing that direction changer and grinding assembly form is cooled, effectively alleviates the thermal deformation problem after continuous processing.

Description

Technical Field

[0001] This utility model relates to the field of machining technology, specifically to a grinding rod for machining ball screw nuts. Background Technology

[0002] When machining nuts for large-lead ball screws, the helix angle increases, and the grinding rod tilt angle also increases, causing interference between the edge of the nut's inner hole and the grinding rod. To address this, patent application number 202510711127.2 discloses a grinding rod structure for grinding internal threads with a large length-to-diameter ratio. The structure includes a grinding rod body, a base, a reversing component, a grinding assembly, a flexible shaft, and a nut. The reversing component is connected to the base at a preset angle, which can be set as needed. The grinding assembly extends into the threaded hole to grind the internal thread, matching the helix angle. This improves machining accuracy while machining large-lead ball screw nuts.

[0003] In the aforementioned grinding rod structure, the reversing component and the grinding assembly form a hydrostatic bearing. Due to the lack of a structure for cooling the hydrostatic bearing, thermal deformation of the hydrostatic bearing occurs after continuous processing, affecting the machining accuracy. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a grinding rod for processing ball screw nuts, which cools the hydrostatic bearing formed by the direction change component and the grinding assembly, and effectively alleviates the problem of thermal deformation after continuous processing.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a grinding rod for processing ball screw nuts, comprising a grinding rod body, a base, a reversing component, a grinding assembly, a flexible shaft, and a nut. The grinding rod body includes a spindle. The base is mounted on the grinding rod body and has a fluid inlet channel inside. The 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 has a throttling channel communicating with the fluid inlet channel. The throttling orifice of the throttling channel is located in the throttling section. An annular first dynamic pressure oil groove is provided on the outer periphery of the throttling section. The grinding assembly is fitted onto the throttling section with clearance. A fluid chamber is formed between the reversing components. The fluid chamber contains a fluid medium for supporting the grinding assembly. An annular second dynamic pressure oil groove is provided on the end face of the grinding assembly. The flexible shaft is rotatable. The flexible shaft passes through the base and the deflector, and extends axially along the base and the deflector in sequence. The flexible shaft is connected to the main shaft. The front end face of the grinding assembly is connected to the flexible shaft through a nut. The flexible shaft drives the grinding assembly to rotate through the nut. The base includes a seat body and a shaft body integrally formed with the seat body. The liquid inlet channel is disposed through the shaft body. The outer circumferential surface of the base is provided with a liquid inlet hole, which is connected to the liquid inlet channel. An eccentric hole is provided in the bottom of the seat body. The front end of the shaft body is provided with an oblique hole at a preset angle to the eccentric hole. The eccentric hole and the oblique hole are connected to form the flexible shaft channel. An air supply channel is also disposed through the shaft body. The outer circumferential surface of the base is provided with an air inlet hole, which is connected to the air supply channel. The end of the shaft body is provided with a fixing groove for the deflector to be embedded. Both the air supply channel and the liquid inlet channel pass through the groove wall of the fixing groove.

[0006] The present invention, which has the above-mentioned features, can introduce cold air by adding air supply channels and air supply holes to cool the hydrostatic bearing formed by the reversing component and the grinding assembly, effectively alleviating the problem of thermal deformation after continuous processing and further ensuring processing accuracy.

[0007] A further feature of this invention is that: an oil inlet hole is provided horizontally on the outer circumferential surface of the seat, and an oil outlet channel connected to the oil inlet hole is provided vertically inside the seat, with the oil outlet of the oil outlet channel located at the upper end of the seat.

[0008] The present invention, which has the above-mentioned features, has an oil inlet hole and an oil outlet channel on the base body, so that cooling oil can flow in to cool the workpiece being processed.

[0009] A further feature of this invention is that the reversing component includes an inner bushing, a bearing, and a thrust plate. The bearing includes a first cylindrical body, a second cylindrical body, and a first convex ring located between the first cylindrical body and the second cylindrical body. The first cylindrical body is interference-fitted into a fixed groove, and the first convex ring abuts against the end face of the shaft. The front end face of the inner bushing is provided with a second convex ring, which is placed at the bottom of the fixed groove. The first cylindrical body abuts against the second convex ring. The grinding assembly is sleeved outside the second cylindrical body, and the inner bushing is inserted into the bearing. A throttling channel is formed between the inner bushing and the bearing. The thrust plate is fitted onto the front end of the inner bushing and presses against the second cylindrical body. The thrust plate and the bearing are used to limit the grinding assembly from both ends.

[0010] The present invention having the above features: the bearing bush is positioned by abutting against the end face of the shaft body through the first convex ring, and the inner bushing is fitted with the bottom of the fixing groove through the second convex ring. Combined with the interference fit method, it is ensured that the bearing bush and the inner bushing do not loosen or shift under high-speed rotation conditions. A further feature of this invention is that the throttling orifice is disposed on the second cylinder, the first cylinder is provided with a through hole communicating with the liquid inlet channel, and a flow channel communicating with the throttling orifice and the through hole is provided between the inner bushing and the bearing. The through hole, the flow channel and the throttling orifice form a throttling channel, and the number of the throttling orifice is at least one pair.

[0011] The present invention, which has the above-mentioned features, has a through hole, a drainage channel, and a throttling hole forming a continuous throttling channel, and the throttling hole is at least a pair, to ensure that the fluid in the inlet channel can be uniformly and stably delivered to the fluid chamber, avoiding the problem of inconsistent fluid film thickness caused by uneven fluid supply from a single throttling hole, and ensuring balanced radial and axial load-bearing capacity; the throttling hole is set in the second cylinder, and combined with the guiding effect of the drainage channel, it can accurately control the flow rate and pressure of the fluid entering the fluid chamber, ensuring the stability of the hydrostatic oil film thickness, further improving the bearing rigidity and load fluctuation resistance, and adapting to different grinding load requirements.

[0012] A further feature of this invention is that the first dynamic pressure oil groove is disposed on the second cylinder and corresponds to the throttling orifice.

[0013] The present invention with the above features is characterized in that the first dynamic pressure oil groove and the throttling orifice are aligned and connected in space, so that the fluid medium flowing out of the throttling orifice can directly enter the first dynamic pressure oil groove, reducing gap loss. The fluid medium in the first dynamic pressure oil groove is dragged by the rotation of the grinding component to form a stronger dynamic pressure effect. After superimposing the static pressure, the overall pressure of the fluid chamber is significantly increased, which can support a larger radial grinding load and reduce the deflection deformation of the grinding wheel during the grinding process.

[0014] A further feature of this invention is that the grinding assembly includes an outer rotor and a grinding wheel mounted on the outer rotor. The outer rotor and a nut are used to fix the grinding wheel from both ends, and the second dynamic pressure oil groove is provided on the end face of the outer rotor.

[0015] The present invention with the above features: the flexible shaft drives the grinding assembly to rotate through the nut, and the nut has the function of power transmission; the outer rotor and the nut form an axial clamp on the grinding wheel from both ends, ensuring that the grinding wheel does not loosen or slip under high-speed rotation and grinding impact.

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model.

[0018] Figure 2 This is a cross-sectional view of an embodiment of the present utility model.

[0019] Figure 3 This is a cross-sectional view of the base of an embodiment of the present utility model.

[0020] Figure 4 This is a cross-sectional view of the directional component and grinding assembly according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the second dynamic pressure oil tank in an embodiment of this utility model. Detailed Implementation

[0022] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0023] like Figure 1-5The grinding rod shown is for machining ball screw nuts, including a grinding rod body (not shown), a base 1, a reversing component 2, a grinding assembly 3, a flexible shaft (not shown), and a nut 6. The grinding rod body includes a spindle (not shown) and is used to provide power and fluid medium. The base 1 is mounted on the grinding rod body and has a liquid inlet channel 11 inside. The liquid inlet channel 11 is used to supply fluid to the throttling channel 21. The fluid has a certain pressure to ensure that a certain dynamic and static pressure is provided. The reversing component 2 is connected to the base 1 at a preset angle, which can be set as needed. The middle part of the reversing component 2 includes a throttling section, and the reversing component 2 is provided with a throttling flow that communicates with the liquid inlet channel 11. The throttling orifice 211 of the throttling channel 21 is set in the throttling section. The outer periphery of the throttling section is provided with an annular first dynamic pressure oil groove 22. The grinding assembly 3 is fitted onto the throttling section with gaps. A fluid chamber 4 is formed between the reversing members 2. The fluid chamber 4 contains a fluid medium for supporting the grinding assembly 3. An annular second dynamic pressure oil groove 31 is provided on the end face of the grinding assembly 3. The flexible shaft 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 is connected to the spindle. The front end face of the grinding assembly 3 is connected to the flexible shaft through the nut 6. The nut 6 is connected to the flexible shaft through a fastening screw (not shown in the figure). The flexible shaft drives the grinding assembly 3 to rotate through the nut 6.

[0024] The base 1 includes a seat body 16 and a shaft 17 integrally formed with the seat body 16. A liquid inlet channel 11 is disposed through the shaft 17. A liquid inlet hole 15 is provided horizontally on the outer circumference of the base 1, and the liquid inlet hole 15 communicates with the liquid inlet channel 11. An eccentric hole 12 is provided in the bottom of the seat body 16. An oblique hole 13 is provided at the front end of the shaft 17 at a preset angle to the eccentric hole 12. The eccentric hole 12 and the oblique hole 13 are connected to form a flexible shaft channel 18. An air supply channel 17 is also provided through the shaft 17. 1. An air inlet 10 is provided horizontally on the outer periphery of the base 1. The air inlet 10 is connected to the air supply channel 171. The end of the shaft 17 is provided with a fixing groove 14 for the reversing component 2 to be embedded. The air supply channel 171 and the liquid inlet channel 11 both pass through the groove wall of the fixing groove 14. An oil inlet 161 is provided horizontally on the outer periphery of the seat 16. An oil outlet channel 162 connected to the oil inlet 161 is provided vertically inside the seat 16. The oil outlet of the oil outlet channel 162 is opened at the upper end of the seat 16.

[0025] The deflector 2 includes an inner bushing 23, a bearing shell 24, and a thrust plate 25. The bearing shell 24 includes a first cylindrical body 241, a second cylindrical body 242, and a first convex ring 243 located between the first cylindrical body 241 and the second cylindrical body 242. The first cylindrical body 241 is interference-fitted into the fixing groove 14. The first convex ring 243 abuts against the end face of the shaft body 17. The front end face of the inner bushing 23 is provided with a second convex ring 231. The second convex ring 231 is placed at the bottom of the fixing groove 14. The first cylindrical body 241 abuts against the second convex ring 231. The grinding assembly 3 is sleeved outside the second cylindrical body 242. The inner bushing 23 is inserted into the bearing shell 24. A throttling channel 21 is formed between the inner bushing 23 and the bearing shell 24. The thrust plate 25 is sleeved on the front end of the inner bushing 23 and presses against the second cylindrical body 242. The thrust plate 25 and the bearing shell 24 are used to limit the grinding assembly 3 from both ends.

[0026] A throttling orifice 211 is provided on the second cylinder 242, and a first dynamic pressure oil groove 22 is provided on the second cylinder 242 and corresponds to the throttling orifice 211. The first cylinder 241 is provided with a through hole 213 that connects to the liquid inlet channel 11. A drainage channel 214 that connects the throttling orifice 211 and the through hole 213 is provided between the inner bushing 23 and the bearing 24. The through hole 213, the drainage channel 214 and the throttling orifice 211 form a throttling channel 21. The number of throttling orifices 211 is at least one pair.

[0027] Grinding assembly 3 includes an outer rotor 32 and a grinding wheel (not shown) mounted on the outer rotor 32. The outer rotor 32 and nut 6 are used to fix the grinding wheel from both ends. A second dynamic pressure oil groove 31 is provided on the end face of the outer rotor 32. The shape of the second dynamic pressure oil groove 31 is as follows: Figure 5 As shown, the second dynamic pressure oil groove 31 on the end face of the grinding assembly 3 generates centrifugal force as it rotates, which throws the fluid out radially and forms an axial dynamic pressure oil film in the gap between the reversing member 2 and the end face of the grinding assembly 3.

[0028] 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. The reversing element 2, the fluid chamber 4, and the grinding assembly 3 together form a hydrostatic bearing, which has the advantages of high precision and good stability when machining the internal threads of nuts. Fluid with a certain pressure flows in through the inlet channel 11 on the base 1, flows through the reversing element 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 pressure allows it to float and detach from the reversing element 2, but its rigidity is determined by the externally provided 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. The dynamic and static pressure bearing structure of this external grinding assembly 3 hardly generates an overturning moment, which greatly improves the machining accuracy of the internal thread.

Claims

1. A grinding rod for machining ball screw nuts, comprising a grinding rod body, a base, a reversing component, a grinding assembly, a flexible shaft, and a nut. The grinding rod body includes a spindle. The base is mounted on the grinding rod body and has an inlet channel therein. The reversing component is connected to the base at a preset angle. The reversing component includes a throttling section in its middle. The reversing component has a throttling channel communicating with the inlet channel. A throttling orifice of the throttling channel is disposed in the throttling section. An annular first dynamic pressure oil groove is provided on the outer periphery of the throttling section. The grinding assembly is fitted onto the throttling section with a clearance, and a fluid chamber is formed between the reversing components. The fluid chamber contains a fluid medium for supporting the grinding assembly. An annular second dynamic pressure oil groove is provided on the end face of the grinding assembly. The flexible shaft rotatably passes through the base and the reversing components, and extends axially along the base and the reversing components in sequence. The flexible shaft is connected to the main shaft. The front end face of the grinding assembly is connected to the flexible shaft via a nut. The flexible shaft drives the grinding assembly to rotate via the nut. The characteristic feature is that: The base includes a seat body and a shaft integrally formed with the seat body. The liquid inlet channel is disposed through the shaft body. The outer peripheral surface of the base is provided with a liquid inlet hole, which is connected to the liquid inlet channel. An eccentric hole is provided in the bottom of the seat body. The front end of the shaft body is provided with an oblique hole at a preset angle to the eccentric hole. The eccentric hole and the oblique hole are connected to form a flexible shaft channel. An air supply channel is also disposed through the shaft body. An air inlet hole is disposed across the outer peripheral surface of the base, which is connected to the air supply channel. The end of the shaft body is provided with a fixing groove for embedding a steering component. Both the air supply channel and the liquid inlet channel pass through the groove wall of the fixing groove.

2. The grinding rod for machining ball screw nuts according to claim 1, characterized in that: The outer circumferential surface of the seat is provided with an oil inlet hole, and the interior of the seat is provided with an oil outlet channel connected to the oil inlet hole. The oil outlet of the oil outlet channel is located at the upper end of the seat.

3. The grinding rod for machining ball screw nuts according to claim 1, characterized in that: The reversing component includes an inner bushing, a bearing shell, and a thrust plate. The bearing shell includes a first cylindrical body, a second cylindrical body, and a first convex ring located between the first cylindrical body and the second cylindrical body. The first cylindrical body is interference-fitted into a fixed groove, and the first convex ring abuts against the end face of the shaft. The front end face of the inner bushing is provided with a second convex ring, which is placed at the bottom of the fixed groove. The first cylindrical body abuts against the second convex ring. The grinding assembly is sleeved outside the second cylindrical body. The inner bushing is inserted into the bearing shell, and a throttling channel is formed between the inner bushing and the bearing shell. The thrust plate is sleeved on the front end of the inner bushing and presses against the second cylindrical body. The thrust plate and the bearing shell are used to limit the grinding assembly from both ends.

4. The grinding rod for machining ball screw nuts according to claim 3, characterized in that: The throttling orifice is provided on the second cylinder, and the first cylinder is provided with a through hole that connects to the liquid inlet channel. A drainage channel connecting the throttling orifice and the through hole is provided between the inner bushing and the bearing. The through hole, the drainage channel and the throttling orifice form a throttling channel, and the number of the throttling orifice is at least one pair.

5. A grinding rod for machining ball screw nuts according to claim 4, characterized in that: The first dynamic pressure oil groove is disposed on the second cylinder and corresponds to the throttling orifice.

6. A grinding rod for machining ball screw nuts according to any one of claims 1-5, characterized in that: The grinding assembly includes an outer rotor and a grinding wheel mounted on the outer rotor. The outer rotor and a nut are used to fix the grinding wheel from both ends. The second hydrostatic oil groove is provided on the end face of the outer rotor.

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