Threaded combined static pressure nut and method of manufacturing the same

Abstract

The application discloses a threaded combined static pressure nut and a manufacturing method thereof, which comprises a screw rod, a nut inner sleeve and a nut outer sleeve; the static pressure nut is in a cylindrical shape, and a trapezoidal inner thread is formed in the inside of the static pressure nut; a plurality of fan-shaped oil cavities are formed on each trapezoidal inner thread in a circumferential direction; a spiral cavity is formed on the outside of the nut inner sleeve; a sleeve thread matched with the spiral cavity is formed on the inside of the nut outer sleeve; after the nut inner sleeve and the nut outer sleeve are matched, a rubber sealing ring completely separates a first fan-shaped oil cavity and a second fan-shaped oil cavity, so that the first fan-shaped oil cavity and the second fan-shaped oil cavity can form different pressures according to external loads; the pressure difference between the two fan-shaped oil cavities resists the external loads, and static pressure bearing is realized; the threaded combined static pressure nut reduces manufacturing cost, and avoids the problem that a milling cutter of a five-axis machine tool cannot extend into the inside of the nut to process the static pressure oil cavity due to a certain depth of the traditional static pressure nut.

Description

Technical Field

[0001] This invention relates to the field of hydrostatic screw drive technology, and in particular to a threaded combination hydrostatic nut and its manufacturing method. Background Technology

[0002] Hydrostatic lubrication is a lubrication technique that uses externally injected pressurized lubricating fluid or gas to form a thin, complete lubricating oil film or gas film on the lubrication surface, thereby completely isolating the two moving surfaces to reduce friction.

[0003] Hydrostatic lubrication technology has matured significantly over the past decades, and numerous research findings have demonstrated its unparalleled superiority through practical application. Hydrostatic lubrication technology possesses many advantages that other lubrication technologies lack, making it particularly suitable for high-speed systems.

[0004] In CNC machine tools, the most common feed method is ball screw transmission. Due to its simple structure, stable operation, and smooth transmission, ball screws are favored in ordinary CNC machine tools. However, as high-end CNC machine tools develop towards higher speeds and higher precision, ball screws, due to their inherent structure, exhibit some inherent drawbacks, such as contact wear and low-speed creep. Competitive alternatives to ball screws mainly include linear motors and hydrostatic nut assemblies.

[0005] A hydrostatic nut assembly, consisting of a lead screw and a hydrostatic nut, is a device that converts rotary motion into linear motion using the principle of threaded transmission. The internal thread of the hydrostatic nut has an oil cavity, which is connected to the oil supply system through an oil hole. Lubricating oil is forced into the oil cavity by pressure, forming a hydrostatic oil film between the tooth surfaces of the lead screw and the hydrostatic nut, completely separating the two relatively moving metal surfaces. This results in high load-bearing capacity, high vibration resistance, low-speed creep-free operation, and high positioning accuracy. However, despite its many advantages, the application of hydrostatic nut assemblies is not widespread, with only some applications in high-precision machine tools and crankshaft / camshaft grinding machines. The main reason is that the hydrostatic oil cavity of the hydrostatic nut is located on the helical surface of the internal thread, making machining difficult.

[0006] Hydrostatic nuts are classified into continuous hydrostatic nuts and discontinuous hydrostatic nuts based on the type of oil cavity. Continuous hydrostatic nuts have a long helical groove (i.e., a hydrostatic oil cavity) on each side of the thread. However, there is a section at the beginning and end of the thread without an oil cavity, serving as a sealing surface. Discontinuous hydrostatic nuts have 3 to 4 pairs of axially opposed fan-shaped hydrostatic oil cavities per thread. These fan-shaped oil cavities are not interconnected and can withstand axial loads, radial loads, and overturning moments. However, due to the depth of the nut, milling cutters or grinding wheels on five-axis machine tools cannot easily reach inside the nut to mill or grind the fan-shaped hydrostatic oil cavities, leading to difficult machining challenges.

[0007] Although 3D printing technology can directly print hydrostatic nuts with discontinuous hydrostatic oil chambers, the processing cost of 3D-printed hydrostatic nuts is too high, and the accuracy of the threads is difficult to guarantee. Furthermore, the material for hydrostatic nuts is limited by the 3D printer. The paper "An Easily Manufactured Multi-Cavity Hydrostatic Screw Nut" (from *Machine Tools & Hydraulics*, 1986, No. 4) proposes a hydrostatic nut structure with elliptical small-hole oil chambers. This involves drilling holes radially from the outside in on the nut, forming elliptical small holes on the thread helical surface. Multiple elliptical small holes are used to replace the hydrostatic oil chambers. This method can only simulate the performance of a hydrostatic screw with discontinuous hydrostatic oil chambers, sacrificing the load-bearing capacity and oil film stiffness of the hydrostatic screw. In the invention patent CN105855813B—"Machining Method of Discontinuous Circular Arc Oil Cavity of Hydrostatic Nut," Lu Changhou uses a wire cutting method to process the discontinuous hydrostatic oil cavity: a first hole and a second hole are drilled at opposite positions on the outer circle of the hydrostatic nut, and a wire is passed through the first hole and the second hole to sequentially cut out the outline and width of one side of the discontinuous hydrostatic oil cavity on the hydrostatic nut, as well as the outline and width of the other side. Using this wire cutting method, the entire hydrostatic nut needs to be cut through at each discontinuous hydrostatic oil cavity, resulting in the depth of the hydrostatic spiral oil cavity being equal to the thickness of the nut wall. If the depth is too large, the dynamic stiffness and damping of the hydrostatic nut will be lost.

[0008] It is evident that improving the structure of the hydrostatic nut makes the intermittent hydrostatic oil cavity on the helical surface of the hydrostatic nut easier to process, reduces the manufacturing difficulty and cost of the hydrostatic nut, and ensures the accuracy of the thread transmission. This is of great significance for the promotion and application of hydrostatic screws and the high-speed and high-precision development of high-end CNC machine tools. Summary of the Invention

[0009] The purpose of this invention is to provide a threaded combination hydrostatic nut and its manufacturing method, which improves the hydrostatic lubrication structure of the hydrostatic nut, making the hydrostatic lubrication structure of the hydrostatic nut easier to implement, reducing the manufacturing cost of the hydrostatic nut, and avoiding the technical problem that the milling cutter of a five-axis machine tool cannot smoothly reach into the nut to process the hydrostatic oil cavity due to the certain depth of the traditional hydrostatic nut.

[0010] To achieve the above objectives, the technical solution of this invention is a threaded hydrostatic nut, comprising a lead screw, an inner sleeve, and an outer sleeve; wherein, the inner sleeve is cylindrical, with a trapezoidal internal thread inside, and multiple discontinuous fan-shaped oil cavities evenly distributed along the circumference and with a wrap angle ranging from 30° to 75° on each turn of the trapezoidal internal thread, the fan-shaped oil cavities axially penetrating the two helical surfaces from the inside of the trapezoidal internal thread, and the center line of the fan-shaped oil cavity is located exactly in the middle position of the threaded mating area of ​​the lead screw and nut; the outer side of the inner sleeve has a helical chamber with the same pitch as the tooth tip position of the trapezoidal internal thread, so that the helical chamber can connect all the fan-shaped oil cavities.

[0011] The nut outer sleeve has a sleeve thread that mates with the spiral chamber. The top of the sleeve thread has a spiral sealing groove, and a rubber sealing ring is installed inside the spiral sealing groove. The gap between the rubber sealing ring and the spiral sealing groove is properly designed, so that the rubber sealing ring has a good sealing effect and service life.

[0012] After the outer sleeve of the nut and the inner sleeve of the nut are threaded together, the sleeve thread divides the sector-shaped oil cavity into a first sector-shaped oil cavity and a second sector-shaped oil cavity that are axially opposed. The first sector-shaped oil cavity and the second sector-shaped oil cavity are completely separated by a rubber sealing ring, ensuring that the first sector-shaped oil cavity and the second sector-shaped oil cavity can form different pressures according to the external load. The pressure difference between the two sector-shaped oil cavities resists the external load and realizes static pressure bearing.

[0013] After the inner sleeve of the nut and the lead screw are engaged, a first throttling gap and a second throttling gap are formed between the helical surfaces of the threads, thereby achieving lubrication of the hydrostatic lead screw pair.

[0014] The nut sleeve has multiple circumferentially distributed first fluid inlet holes arranged axially inside. Between the first fluid inlet holes and the helical surface of the sleeve thread, there are multiple radial second fluid inlet holes. The second fluid inlet holes allow lubricating oil to flow into the first sector-shaped oil cavity and the second sector-shaped oil cavity.

[0015] A flange is further provided at one end of the outer sleeve of the nut, and multiple threaded mounting holes are further provided on the flange for the installation of the hydrostatic nut and the nut seat.

[0016] The fluid medium in the threaded hydrostatic nut can be either a liquid medium such as lubricating oil or a gaseous medium. The flow path of the fluid medium is as follows: it enters the first sector-shaped oil cavity and the second sector-shaped oil cavity through the first fluid inlet hole and multiple second fluid inlets holes, and then flows to the first throttling gap and the second throttling gap respectively to achieve hydrostatic support, and then flows out of the hydrostatic nut through the gap between the thread tooth tip and the tooth root.

[0017] When the threaded hydrostatic nut is subjected to external loads, the first throttling gap decreases while the second throttling gap increases. Taking the decrease in the first throttling gap and the increase in the second throttling gap as an example, the decrease in the first throttling gap leads to an increase in the flow resistance of the first throttling gap, which in turn leads to an increase in pressure within the first sector-shaped oil cavity; the increase in the second throttling gap leads to a decrease in the flow resistance of the second throttling gap, which in turn leads to a decrease in pressure within the second sector-shaped oil cavity. The pressure difference between the first and second sector-shaped oil cavities resists the external load, achieving hydrostatic bearing.

[0018] The manufacturing method of the threaded combination hydrostatic nut of the present invention includes the following steps:

[0019] Step 1: Using a cylindrical bar stock, machine the outer cylindrical surface of the cylinder, and perform rough machining, semi-finish machining, and finish machining to produce the trapezoidal internal thread of the inner sleeve of the nut;

[0020] Step 2: Using wire cutting, deep hole drilling or milling, axially drill through the entire trapezoidal internal thread from beginning to end to process multiple fan-shaped oil cavities evenly distributed along the circumference and with a wrap angle range of 30° to 75°.

[0021] Step 3: Use forming turning, milling or grinding to machine a spiral chamber on the outside of the inner sleeve of the nut, so that the spiral chamber can communicate with all the sector oil chambers;

[0022] Step 4: Machining the nut outer sleeve, including: rough machining, semi-finish machining, and finish machining to create sleeve threads that mate with the helical chamber, and machining a helical sealing groove at the top of the sleeve threads; machining multiple first fluid inlet holes evenly distributed along the circumference at one end of the nut outer sleeve, and machining multiple second fluid inlet holes on each first fluid inlet hole; machining a flange and threaded mounting holes at one end of the nut outer sleeve, and performing conventional machining processes such as deburring and final heat treatment;

[0023] Step 5: Assemble the outer sleeve of the nut and the inner sleeve of the nut. After the threaded connection, the sleeve thread divides the sector-shaped oil cavity into a first sector-shaped oil cavity and a second sector-shaped oil cavity that are axially opposed, and the first sector-shaped oil cavity and the second sector-shaped oil cavity are completely separated by a rubber sealing ring.

[0024] The advantages of a threaded combination hydrostatic nut manufactured using the technical solution of the present invention are: (1) By using wire cutting, deep hole drilling or milling, the entire trapezoidal internal thread is axially drilled from beginning to end, resulting in multiple discontinuous fan-shaped oil cavities evenly distributed along the circumferential direction with a wrap angle range of 30° to 75°. This makes the hydrostatic lubrication structure of the hydrostatic nut easier to realize, reduces the manufacturing cost of the hydrostatic nut, and avoids the technical problem that the milling cutter of a five-axis machine tool cannot smoothly reach into the nut to process the hydrostatic oil cavity due to the certain depth of the traditional hydrostatic nut. At the same time, it avoids the problem of using wire cutting to process the hydrostatic oil cavity of the hydrostatic nut in the invention patent CN105855813B, which affects the dynamic stiffness and Damping attenuation; (2) A spiral chamber with the same pitch as the trapezoidal internal thread tooth tip is opened on the outside of the inner sleeve of the nut, and a sleeve thread that matches the spiral chamber is opened inside the outer sleeve of the nut. After the inner sleeve of the nut and the outer sleeve of the nut are fitted together, the rubber sealing ring completely separates the first sector oil chamber and the second sector oil chamber, ensuring that the first sector oil chamber and the second sector oil chamber can form different pressures according to the external load. The pressure difference between the two sector oil chambers resists the external load and realizes static pressure bearing; (3) The fluid medium of the threaded combination static pressure nut of the present invention can be a liquid medium such as lubricating oil, or a gas medium; thus, it can realize the liquid static pressure screw pair transmission or the gas static pressure screw pair transmission. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the threaded combination hydrostatic nut of the present invention;

[0026] Figure 2 This is a longitudinal cross-sectional view of the threaded combination hydrostatic nut of the present invention;

[0027] Figure 3 This is a partial cross-sectional view of the area where the inner sleeve of the nut mates with the threaded part of the lead screw, according to the present invention.

[0028] Figure 4 This is a longitudinal cross-sectional view of the inner sleeve of the nut according to the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the inner sleeve of the nut of the present invention;

[0030] Figure 6 This is a longitudinal cross-sectional view of the nut outer sleeve of the present invention.

[0031] In the above figures,

[0032] 1. Lead screw;

[0033] 2. Nut inner sleeve; 21. Trapezoidal internal thread; 22. Fan-shaped oil cavity; 23. Helical chamber; 21-1. First throttling gap; 21-2. Second throttling gap; 22-1. First fan-shaped oil cavity; 22-2. Second fan-shaped oil cavity;

[0034] 3. Nut outer sleeve; 31. Sleeve thread; 32. Spiral sealing groove; 33. First fluid inlet; 34. Second fluid inlet; 35. Flange; 36. Threaded mounting hole; 37. Rubber sealing ring. Detailed Implementation

[0035] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments:

[0036] A type of threaded combination hydrostatic nut, such as Figure 1 As shown, it includes a lead screw 1, an inner nut sleeve 2, and an outer nut sleeve 3; wherein, the structure of the inner nut sleeve 2 is as follows: Figure 4 and Figure 5 As shown, the inner sleeve 2 of the nut is cylindrical, with a trapezoidal internal thread 21 inside. Each turn of the trapezoidal internal thread 21 has four discontinuous fan-shaped oil cavities 22 evenly distributed along the circumference with a wrap angle of 60°. The fan-shaped oil cavities 22 axially penetrate the two helical surfaces from inside the trapezoidal internal thread 21, ensuring that the center line of the fan-shaped oil cavity 22 is located precisely in the middle of the screw nut thread mating area. Figure 3 As shown; the inner sleeve 2 of the nut has a spiral chamber 23 on the outside that corresponds to the tooth tip position of the trapezoidal internal thread 21 and has the same pitch, so that the spiral chamber 23 can connect all the fan-shaped oil chambers 22.

[0037] The structure of the nut outer sleeve 3 is as follows Figure 6 As shown, the sleeve thread 31 that mates with the spiral chamber 23 is opened inside. The top of the sleeve thread 31 has a spiral sealing groove 32. A rubber sealing ring 37 is installed inside the spiral sealing groove 32. The gap between the rubber sealing ring 37 and the spiral sealing groove 32 is properly designed, so that the rubber sealing ring 37 has a good sealing effect and service life.

[0038] like Figure 2 and 3 As shown, after the outer sleeve 3 and the inner sleeve 2 of the nut are threaded together, the sleeve thread 31 divides the sector-shaped oil cavity 22 into a first sector-shaped oil cavity 22-1 and a second sector-shaped oil cavity 22-2 that are axially opposed. The first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2 are completely separated by the rubber sealing ring 37, ensuring that the first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2 can form different pressures according to the external load. The pressure difference between the two sector-shaped oil cavities resists the external load and realizes static pressure bearing.

[0039] Furthermore, after the inner sleeve 2 of the nut and the lead screw 1 are engaged, a first throttling gap 21-1 and a second throttling gap 21-2 are formed between the helical surfaces of the thread, thus realizing the lubrication of the hydrostatic lead screw pair.

[0040] Furthermore, the inner side of the nut sleeve 3 is provided with four circumferentially distributed first fluid inlet holes 33. Between the first fluid inlet holes 33 and the helical surface of the sleeve thread 31, there are multiple radial second fluid inlet holes 34. The second fluid inlet holes 34 guide the lubricating oil to the first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2.

[0041] Furthermore, a flange 35 is provided at one end of the nut outer sleeve 3, and four threaded mounting holes 36 are provided on the flange 35 for the installation of the hydrostatic nut and the nut seat.

[0042] Furthermore, the fluid medium in the threaded combination hydrostatic nut of the present invention can be either a liquid medium such as lubricating oil or a gas medium. The flow path of the fluid medium is as follows: it enters the first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2 through the first fluid inlet 33 and multiple second fluid inlets 34, and then flows to the first throttling gap 21-1 and the second throttling gap 21-2 respectively to achieve hydrostatic support, and then flows out of the hydrostatic nut through the gap between the thread tooth tip and the tooth root.

[0043] Furthermore, when the threaded combination hydrostatic nut of the present invention bears an external load, it causes one of the first throttling gaps 21-1 and the other of the second throttling gap 21-2 to decrease and the other to increase. Taking the decrease of the first throttling gap 21-1 and the increase of the second throttling gap 21-2 as an example, the decrease of the first throttling gap 21-1 leads to an increase in the flow resistance of the first throttling gap 21-1, which in turn leads to an increase in the pressure in the first sector-shaped oil cavity 22-1; the increase of the second throttling gap 21-2 leads to a decrease in the flow resistance of the second throttling gap 21-2, which in turn leads to a decrease in the pressure in the second sector-shaped oil cavity 22-2. The pressure difference between the first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2 resists the external load and achieves hydrostatic bearing.

[0044] The manufacturing method of the threaded combination hydrostatic nut of the present invention includes the following steps:

[0045] Step 1: Using a cylindrical bar stock, machine the outer cylindrical surface of the cylinder, and perform rough machining, semi-finishing, and finishing to produce the trapezoidal internal thread 21 of the inner sleeve 2 of the nut;

[0046] Step 2: Using wire cutting, deep hole drilling or milling, drill the entire trapezoidal internal thread 21 axially from beginning to end to process 4 fan-shaped oil cavities 22 evenly distributed along the circumference and with a wrap angle of 60°.

[0047] Step 3: Use forming turning, milling or grinding to machine a spiral chamber 23 on the outside of the inner sleeve 2 of the nut, so that the spiral chamber 23 can be connected to all the fan-shaped oil chambers 22;

[0048] Step 4: Machining the nut outer sleeve 3, including: rough machining, semi-finishing, and finishing to produce a sleeve thread 31 that mates with the helical chamber 23, and machining a helical sealing groove 32 at the top of the sleeve thread 31; machining multiple first fluid inlet holes 33 evenly distributed along the circumferential direction at one end of the nut outer sleeve 3, and machining multiple second fluid inlet holes 34 on each first fluid inlet hole 33; machining a flange 35 and a threaded mounting hole 36 at one end of the nut outer sleeve 3, and performing conventional machining processes such as deburring and final heat treatment;

[0049] Step 5: Assemble the outer sleeve 3 of the nut and the inner sleeve 2 of the nut. After the threaded engagement, the sleeve thread 31 divides the sector-shaped oil cavity 22 into a first sector-shaped oil cavity 22-1 and a second sector-shaped oil cavity 22-2 that are axially opposed, and completely separates the first sector-shaped oil cavity 22-1 and the second sector-shaped oil cavity 22-2 by the rubber sealing ring 37.

[0050] In this embodiment, the threaded hydrostatic nut is machined axially from beginning to end through the entire trapezoidal internal thread using methods such as wire cutting, deep hole drilling, or milling. This results in multiple discontinuous fan-shaped oil cavities evenly distributed along the circumference with a wrap angle of 60°. This facilitates the realization of the hydrostatic lubrication structure of the hydrostatic nut, reduces its manufacturing cost, and avoids the technical difficulty of traditional hydrostatic nuts where the milling cutter on a five-axis machine tool cannot easily reach into the nut to machine the hydrostatic oil cavity due to its depth. It also avoids the attenuation of dynamic stiffness and damping caused by the wire cutting method used in the hydrostatic oil cavity machining of the hydrostatic nut in invention patent CN105855813B. In this embodiment, a thread with the same pitch corresponding to the tooth tip position of the trapezoidal internal thread is opened on the outside of the inner sleeve of the nut. The spiral chamber has a sleeve thread inside the nut outer sleeve that mates with the spiral chamber. After the inner sleeve and outer sleeve of the nut are engaged, the rubber sealing ring completely separates the first and second sector-shaped oil chambers, ensuring that the first and second sector-shaped oil chambers can form different pressures according to the external load. The pressure difference between the two sector-shaped oil chambers resists the external load, achieving hydrostatic bearing. In this embodiment, the fluid medium of the threaded combination hydrostatic nut can be a liquid medium such as lubricating oil or a gas medium, thereby realizing the transmission of a liquid hydrostatic screw pair or a gas hydrostatic screw pair. This makes the fluid hydrostatic lubrication structure of the hydrostatic nut easy to implement, which is of great significance for the promotion and application of hydrostatic screws and the development of high-speed and high-precision high-end CNC machine tools.

[0051] The present invention has been described above with reference to preferred embodiments, but the scope of protection of the present invention is not limited thereto. Various modifications can be made to the invention without departing from its scope, and equivalent components can be substituted. As long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner. Furthermore, no reference numerals in the claims should be considered as limiting the scope of the claims. In all respects, the embodiments should be considered exemplary and non-limiting. Therefore, all technical solutions falling within the scope of the claims are within the protection scope of the present invention.

Claims

1. A threaded combination hydrostatic nut, characterized in that, The system includes a lead screw (1), an inner sleeve (2) for the nut, and an outer sleeve (3) for the nut. The inner sleeve (2) for the nut is cylindrical and has a trapezoidal internal thread (21) inside. Each turn of the trapezoidal internal thread (21) has multiple discontinuous fan-shaped oil cavities (22) that are evenly distributed along the circumference and have a wrap angle ranging from 30° to 75°. The fan-shaped oil cavities (22) axially penetrate the two helical surfaces from inside the trapezoidal internal thread (21) and make the center line of the fan-shaped oil cavities (22) exactly located in the middle of the thread mating area of ​​the lead screw and nut. The inner sleeve (2) for the nut has a helical chamber (23) on the outside that corresponds to the tooth tip position of the trapezoidal internal thread (21) and has the same pitch, so that the helical chamber (23) can connect all the fan-shaped oil cavities (22). The inner side of the nut outer sleeve (3) has a sleeve thread (31) that matches the spiral chamber (23). The top of the sleeve thread (31) has a spiral sealing groove (32). A rubber sealing ring (37) is installed inside the spiral sealing groove (32). After the outer sleeve (3) of the nut and the inner sleeve (2) of the nut are threaded together, the sleeve thread (31) divides the sector oil cavity (22) into a first sector oil cavity (22-1) and a second sector oil cavity (22-2) that are axially opposed. The first sector oil cavity (22-1) and the second sector oil cavity (22-2) are completely separated by the rubber sealing ring (37), ensuring that the first sector oil cavity (22-1) and the second sector oil cavity (22-2) can form different pressures according to the external load. The pressure difference between the two sector oil cavities resists the external load and realizes static pressure bearing.

2. The threaded combination hydrostatic nut according to claim 1, characterized in that, After the inner sleeve (2) of the nut and the lead screw (1) are engaged, a first throttling gap (21-1) and a second throttling gap (21-2) are formed between the helical surfaces of the thread, thus realizing the lubrication of the hydrostatic lead screw pair.

3. A threaded combination hydrostatic nut according to claim 1, characterized in that, The nut sleeve (3) has multiple circumferentially distributed first fluid inlet holes (33) inside. Multiple radial second fluid inlet holes (34) are provided between the first fluid inlet holes (33) and the spiral surface of the sleeve thread (31). The second fluid inlet holes (34) pass lubricating oil to the first sector oil cavity (22-1) and the second sector oil cavity (22-2).

4. A threaded combination hydrostatic nut according to claim 1, characterized in that, A flange (35) is further provided at one end of the nut outer sleeve (3), and a plurality of threaded mounting holes (36) are further provided on the flange (35) for the installation of the hydrostatic nut and the nut seat.

5. A threaded combination hydrostatic nut according to claim 1, characterized in that, The fluid medium for threaded hydrostatic nuts can be either a liquid medium such as lubricating oil or a gas medium.

6. A threaded combination hydrostatic nut according to claim 3, characterized in that, The fluid medium enters the first sector oil cavity (22-1) and the second sector oil cavity (22-2) through the first fluid inlet (33) and multiple second fluid inlets (34), and then flows to the first throttling gap (21-1) and the second throttling gap (21-2) respectively to achieve static pressure support, and then flows out of the static pressure nut through the gap between the thread tooth top and the tooth bottom.

7. A threaded combination hydrostatic nut according to claim 2, characterized in that, When the threaded combination hydrostatic nut bears an external load, it causes one of the first throttling gaps (21-1) and the other of the second throttling gap (21-2) to decrease and the other to increase. Taking the decrease of the first throttling gap (21-1) and the increase of the second throttling gap (21-2) as an example, the decrease of the first throttling gap (21-1) leads to an increase in the flow resistance of the first throttling gap (21-1), which in turn leads to an increase in the pressure in the first sector oil cavity (22-1); the increase of the second throttling gap (21-2) leads to a decrease in the flow resistance of the second throttling gap (21-2), which in turn leads to a decrease in the pressure in the second sector oil cavity (22-2). The pressure difference between the first sector oil cavity (22-1) and the second sector oil cavity (22-2) resists the external load and realizes hydrostatic bearing.

8. A method for manufacturing a threaded combination hydrostatic nut according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Using a cylindrical bar stock, process the outer cylindrical surface of the cylinder, and perform rough machining-semi-finish machining-finish machining to produce the trapezoidal internal thread (21) of the inner sleeve (2) of the nut. Step 2: Using wire cutting, deep hole drilling or milling, drill the entire trapezoidal internal thread axially from beginning to end (21) to process multiple fan-shaped oil cavities (22) that are evenly distributed along the circumference and have a wrap angle range of 30° to 75°. Step 3: Use forming turning, milling or grinding to machine a spiral chamber (23) on the outside of the inner sleeve (2) of the nut, so that the spiral chamber (23) can communicate with all the fan-shaped oil chambers (22); Step 4: Machining the nut outer sleeve (4), including: rough machining - semi-finishing - finishing machining to produce sleeve threads (31) that cooperate with the spiral chamber (23), and machining a spiral sealing groove (32) on the top of the sleeve thread (31); machining multiple first fluid inlet holes (33) evenly distributed in the circumferential direction at one end of the nut outer sleeve (3), and machining multiple second fluid inlet holes (34) on each first fluid inlet hole (33); machining a flange (35) and a threaded mounting hole (36) at one end of the nut outer sleeve (3), and performing conventional machining processes such as deburring and final heat treatment; Step 5: Assemble the outer sleeve (3) of the nut and the inner sleeve (2) of the nut. After the threaded connection, the sleeve thread (31) divides the sector oil cavity (22) into the first sector oil cavity (22-1) and the second sector oil cavity (22-2) which are axially opposed. The first sector oil cavity (22-1) and the second sector oil cavity (22-2) are completely separated by the rubber sealing ring (37).

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