Hydrostatic spindle and machine tool

Abstract

This invention discloses a hydrostatic spindle and machine tool. The hydrostatic spindle includes a spindle assembly and a sealing device. The spindle assembly includes a mounting component and a shaft core. The shaft core is rotatably mounted in a mounting hole of the mounting component. An oil return chamber and an oil return gap are provided between the outer circumferential surface of the shaft core and the inner wall surface of the mounting hole. The oil return gap is located on one side of the oil return chamber along the axial direction of the shaft core and communicates with the oil return chamber. The sealing device includes an annular mounting seat, a sealing component, and an elastic telescopic component. The annular mounting seat is sleeved on the shaft core and connected to the mounting component. The sealing component is connected to the side of the annular mounting seat near the oil return gap through the elastic telescopic component and forms an airtight cavity between it and the mounting component. The sealing component can move to a first position to block the oil return gap under the action of the telescopic force of the elastic telescopic component, and move to a second position away from the oil return gap when gas is introduced into the airtight cavity. This invention solves the problem of oil leakage in hydrostatic spindles.

Description

Technical Field

[0001] This application relates to the field of machine tool technology, and more specifically, to a hydrostatic spindle and machine tool. Background Technology

[0002] As a core component of ultra-precision machine tools, the precision and rigidity of the hydrostatic spindle significantly influence the machining accuracy of parts. The hydrostatic spindle uses hydrostatic bearings as support components. These bearings rely on an external hydraulic oil supply system to forcibly inject lubricating oil, creating a pressurized oil film. This pressurized oil film separates the relatively moving parts from the support, achieving full hydrostatic friction. Therefore, hydrostatic spindles possess advantages such as low frictional resistance, long service life, wide speed range, good vibration resistance, high spindle rotation accuracy, and good adaptability, making them widely used in the field of ultra-precision machine tool machining.

[0003] However, the oil leakage problem of the hydrostatic spindle persists even after the machine tool is shut down and the air supply is cut off, especially in vertical spindles where the leakage is more severe. Because the oil return path in a vertical hydrostatic spindle, which connects to the oil return chamber, is vertical, when the air supply to this path is cut off, residual oil flows back into the oil return chamber. After the air seal closes, this residual oil flows out from the oil return chamber along the return path, causing leakage. This leakage affects the amount of oil stored in the hydraulic station, increases the operating cost of the hydrostatic spindle, and also affects the overall aesthetics of the ultra-precision machine tool. Summary of the Invention

[0004] The main objective of this application is to provide a hydrostatic spindle and machine tool to solve the problem of oil leakage in hydrostatic spindles mentioned in the background art.

[0005] According to one aspect of this application, a hydrostatic spindle is provided, comprising:

[0006] A spindle assembly includes a mounting component and a spindle core. The mounting component has a mounting hole, and the spindle core is rotatably mounted in the mounting hole. A return oil chamber and a return oil gap are provided between the outer peripheral surface of the spindle core and the inner wall surface of the mounting hole. The return oil gap is located on one side of the return oil chamber along the axial direction of the spindle core and communicates with the return oil chamber. The return oil gap is used to allow the hydraulic oil in the return oil chamber to flow back to the hydraulic station under venting conditions.

[0007] A sealing device, comprising an annular mounting seat, a sealing component, and an elastic telescopic component, wherein the annular mounting seat is sleeved on the shaft core and connected to the mounting assembly, and the sealing component is connected to the side of the annular mounting seat near the oil return gap through the elastic telescopic component and forms an airtight cavity between the sealing component and the mounting assembly.

[0008] The sealing component has the ability to move to a first position to block the oil return gap under the action of the elastic telescopic force, and to move to a second position away from the oil return gap when gas is introduced into the gas-tight cavity.

[0009] Furthermore, the airtight cavity includes a first airtight cavity, and the sealing component includes:

[0010] An annular mounting component is sleeved on the shaft core, and the side of the annular mounting component away from the oil return gap is connected to the elastic expansion component.

[0011] An annular sealing gasket is disposed on the annular mounting member near the oil return gap. The annular sealing gasket is used to block the oil return gap when the sealing member moves to the first position, and forms a first airtight cavity between the annular mounting member and the mounting assembly. The first airtight cavity communicates with the oil return gap after the annular sealing gasket moves to the second position.

[0012] Furthermore, the shaft core is provided with a first annular flange, which is in clearance fit with the inner wall of the mounting hole to form the oil return gap, and the projection of the oil return gap along the axial direction of the shaft core is located on the annular sealing gasket.

[0013] Furthermore, the mounting assembly is provided with a first air passage, which is connected to the first airtight cavity, and the first air passage is used to introduce airflow into the first airtight cavity.

[0014] Furthermore, the gas-tight cavity also includes a second gas-tight cavity. A second annular flange is provided on the outer periphery of the annular mounting member away from the shaft core. The second annular flange and the mounting assembly surround to form the second gas-tight cavity. The second gas-tight cavity is used to move the annular mounting member to the second position when gas is introduced.

[0015] Furthermore, the mounting assembly is also provided with a second air passage and a first groove. The second air passage is connected to the bottom of the first groove, and the second annular flange is at least partially located in the first groove and forms a second airtight cavity with the bottom of the first groove.

[0016] Furthermore, the sealing component also includes:

[0017] The sealing rings include at least two, which are disposed between the sidewalls of the second annular flange and the first groove and are respectively located on opposite sides of the second annular flange along its own radial direction. The sealing rings are used to seal the installation gap between the second annular flange and the first groove.

[0018] Furthermore, the mounting components include:

[0019] The mounting housing is in which the shaft is mounted via a hydrostatic bearing;

[0020] An oil return block is disposed within the mounting housing. The oil return block has a mounting hole. The shaft core is at least partially inserted into the mounting hole to form the oil return cavity and the oil return gap between the shaft core and the mounting hole. The first air passage and the second air passage are both disposed on the oil return block.

[0021] Furthermore, a third annular flange is provided on the side of the oil return block away from the mounting hole. The third annular flange seals and abuts against the mounting shell and the annular mounting seat. A second groove is provided on the wall of the mounting hole. The oil return cavity is formed between the second groove and the outer peripheral surface of the shaft core. The first groove is provided on the oil return block and is located between the second groove and the third annular flange.

[0022] Furthermore, a fourth annular flange is formed between the first groove and the second groove, and the oil return gap is located between the fourth annular flange and the outer peripheral surface of the shaft core; wherein, the side of the annular sealing gasket near the oil return gap protrudes from the surface of the annular mounting member near the fourth annular flange, and forms the first airtight cavity between the sealing member and the fourth annular flange and the annular mounting member when the sealing member moves to the first position.

[0023] According to another aspect of this application, a machine tool is provided, the machine tool including the aforementioned hydrostatic spindle.

[0024] Compared with the prior art, the technical solution of this application has at least the following technical effects:

[0025] This application provides a sealing component on one side of the return oil gap of a hydrostatic spindle. After the air supply to the return oil gap is cut off, the sealing component moves to a first position, blocking the return oil gap, under the action of the elastic expansion joint, thus preventing hydraulic oil leakage. When gas is introduced into the airtight chamber, the sealing component moves to a second position away from the return oil gap under the pressure of the gas, overcoming the expansion force of the elastic expansion joint, allowing air to pass through the return oil gap to push the hydraulic oil in the return oil chamber to the hydraulic station. Even for vertical spindles with a vertical return oil gap, the sealing component prevents oil from leaking out of the return oil chamber after the air supply to the vertical return oil gap is cut off, thus avoiding oil leakage. Therefore, this application, by using a sealing component to block the return oil gap after the air supply is cut off, ensures the amount of oil remaining in the hydraulic station and reduces the operating cost of the hydrostatic spindle. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0027] Figure 1 This is a schematic diagram of the assembly structure of a hydrostatic spindle and a sealing device according to an embodiment of the present invention;

[0028] Figure 2 for Figure 1 An enlarged schematic diagram of part A in the middle;

[0029] Figure 3 This is a schematic diagram illustrating the connection between the second air passage and the second airtight cavity;

[0030] Figure 4 This is a schematic diagram of a ring-shaped mounting component being mounted on a ring-shaped mounting base via a spring.

[0031] Figure 5 This is a three-dimensional structural diagram of the ring-shaped mounting base;

[0032] Figure 6 This is a schematic diagram of the three-dimensional structure of the oil return block;

[0033] Figure 7 This is a schematic diagram of the structure of the oil return block near the annular mounting component.

[0034] The above figures include the following reference numerals:

[0035] 11. Mounting housing; 12. Oil return block; 121. First air passage; 122. Second air passage; 123. First groove; 124. Mounting hole; 125. Third annular flange; 126. Second groove; 127. Fourth annular flange; 20. Shaft core; 21. First annular flange; 22. Oil return chamber; 23. Oil return gap; 30. Annular mounting seat; 301. Clearance groove; 302. Mounting groove; 31. Annular mounting piece; 311. Second annular flange; 32. Annular sealing gasket; 33. Spring; 34. Sealing ring; 41. First airtight chamber; 42. Second airtight chamber. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0039] To address the oil leakage problem in hydrostatic spindles (especially vertical hydrostatic spindles), the first embodiment of this invention provides a hydrostatic spindle comprising a spindle assembly and a sealing device. Please refer to... Figures 1 to 4 (Since the structure of other parts of the hydrostatic spindle is unrelated to the solution provided in this embodiment of the invention, therefore...) Figure 1 , Figure 3 and Figure 4 (The structure of other parts is omitted by using a break line drawing method). In this embodiment of the invention, the spindle component includes a mounting assembly and a spindle core 20. The mounting assembly is provided with a mounting hole 124, and the spindle core 20 is rotatably mounted in the mounting hole 124. A return oil cavity 22 and a return oil gap 23 are provided between the outer peripheral surface of the spindle core 20 and the inner wall surface of the mounting hole 124. The return oil gap 23 is located on one side of the return oil cavity 22 along the axial direction of the spindle core 20 and communicates with the return oil cavity 22. The return oil gap 23 is used to allow the hydraulic oil in the return oil cavity 22 to flow back to the hydraulic station in the vented state. The sealing device includes an annular mounting seat 30, a sealing component, and an elastic telescopic component. The annular mounting seat 30 is sleeved on the spindle core 20 and connected to the mounting assembly. The sealing component is connected to the side of the annular mounting seat 30 near the return oil gap 23 through the elastic telescopic component and forms an airtight cavity between it and the mounting assembly. The sealing component has the ability to move to a first position to block the return oil gap 23 under the action of the elastic expansion force of the elastic expansion member, and to move to a second position away from the return oil gap 23 when gas is introduced into the gas-tight cavity.

[0040] When no gas is introduced into the gas-sealed cavity, the sealing component remains in the first position, blocking the return oil gap 23. Regardless of whether the hydrostatic spindle is horizontally or vertically positioned, hydraulic oil will not leak from the return oil gap 23. During operation, gas with a predetermined pressure can be introduced into the gas-sealed cavity. Under the pressure of the gas, the sealing component overcomes the elastic force of the telescopic member and moves to the second position, allowing gas to pass through the return oil gap 23 and pushing the hydraulic oil in the return oil cavity 22 to the hydraulic station. After the gas supply to the return oil gap 23 and the gas-sealed cavity in the hydrostatic spindle is cut off, the sealing component moves back to the first position, blocking the return oil gap 23, under the force of the elastic telescopic member to prevent oil leakage. Therefore, this embodiment eliminates oil leakage after the gas supply to the hydrostatic spindle is cut off, saving hydraulic oil, simplifying the cleaning of the machine tool equipped with the hydrostatic spindle, improving the overall aesthetics of the machine tool, and reducing the machine tool's start-up costs.

[0041] Therefore, this embodiment provides a sealing component on one side of the return oil gap 23 of the hydrostatic spindle. After the air supply to the return oil gap 23 is cut off, the sealing component moves to a first position, blocking the return oil gap 23, under the action of the elastic expansion member, thus preventing hydraulic oil leakage from the return oil gap 23. When gas is introduced into the airtight chamber, the sealing component overcomes the expansion force of the elastic expansion member under air pressure and moves to a second position away from the return oil gap 23, allowing the return oil gap 23 to be vented to push the hydraulic oil in the return oil chamber 22 to the hydraulic station. Even in a vertical spindle where the return oil gap 23 is vertical, the sealing component prevents oil leakage from the return oil chamber 22 after the air supply to the vertical return oil gap 23 is cut off. Therefore, this embodiment uses a sealing component to block the return oil gap 23 after the air supply is cut off, ensuring the amount of oil remaining in the hydraulic station and reducing the operating cost of the hydrostatic spindle.

[0042] In this embodiment, the airtight cavity includes a first airtight cavity 41, and the sealing components include an annular mounting member 31 and an annular sealing gasket 32. The annular mounting member 31 is sleeved on the shaft core 20, and the side of the annular mounting member 31 away from the oil return gap 23 is connected to the elastic telescopic member so that it can approach the oil return gap 23 along the axial direction of the shaft core 20 under the action of the telescopic force of the elastic telescopic member. The annular sealing gasket 32 ​​is disposed at the position of the annular mounting member 31 near the oil return gap 23. The annular sealing gasket 32 ​​is used to block the oil return gap 23 when the sealing component moves to the first position, and forms the first airtight cavity 41 between the annular mounting member 31 and the mounting assembly. The first airtight cavity 41 communicates with the oil return gap 23 after the annular sealing gasket 32 ​​moves to the second position. When the machine tool is started, gas at a predetermined pressure can be introduced into the first air-sealed cavity 41. Under the action of air pressure, the annular mounting part 31 drives the annular sealing gasket 32 ​​to move to the second position. At this time, since the first air-sealed cavity 41 is connected to the oil return gap 23, the gas can enter the oil return cavity 22 through the oil return gap 23. The gas and the hydraulic oil in the oil return cavity 22 flow back to the hydraulic station together. When the machine tool is shut down and the air supply is cut off, since the first air-sealed cavity 41 is not vented, the annular mounting part 31 no longer bears the pressure of the air pressure. In other words, at this time, the elastic force of the elastic expansion member is greater than the pressure of the air pressure in the first air-sealed cavity 41. Then, under the action of the elastic force of the elastic expansion member, the annular mounting part 31 can move towards the first position closer to the oil return gap 23 until the annular sealing gasket 32 ​​blocks the oil return gap 23.

[0043] As can be seen, in this embodiment, the first airtight chamber 41, when the machine tool is turned on and air is supplied to it, not only allows the sealing component to move to the second position under air pressure to open the oil return gap 23, but also allows gas to enter the oil return gap 23 through the connection between the oil return gap 23 and the first airtight chamber 41, thereby transporting the hydraulic oil in the oil return chamber 22 to the hydraulic station. After the machine tool is turned off and the air supply is cut off, the sealing component can move back to the first position under the action of elastic extension force to seal the oil return gap 23 and prevent oil leakage. The connection between the first airtight chamber 41 and the oil return gap 23 makes the closing and opening of the oil return gap 23 of the hydrostatic spindle more convenient and faster, with high oil return efficiency, and makes the overall structure of the hydrostatic spindle compact and easy to install.

[0044] In this embodiment, the spindle core 20 of the main spindle component is provided with a first annular flange 21. The first annular flange 21 is clearance-fitted with the inner wall of the mounting hole 124 to form an oil return gap 23, and the projection of the oil return gap 23 along the axial direction of the spindle core 20 is located on the annular sealing gasket 32. Thus, when the sealing component moves to the first position, the annular sealing gasket 32 ​​at least partially abuts against the first annular flange 21 and seals the oil return gap 23, preventing the oil stored in the oil return cavity 22 from leaking out from the oil return gap 23.

[0045] In this embodiment, the annular sealing gasket 32 ​​may include one of expanded polytetrafluoroethylene (PTFE) gaskets, nitrile rubber gaskets, etc. The expanded PTFE gaskets or nitrile rubber gaskets can be pressed against the first annular flange 21 and the mounting assembly under the stretching force of the elastic expansion member, thereby sealing the oil return gap 23 between the first annular flange 21 and the mounting assembly. The elastic expansion member may include a spring 33 or a tubular elastic sensitive element (such as a bellows). In this embodiment, the elastic expansion member is preferably a spring 33. To this end, in order to install the spring 33 on the side of the annular mounting member 31 away from the oil return gap 23, this embodiment provides a clearance groove 301 on the side of the annular mounting seat 30 near the annular mounting member 31. Figure 4 and Figure 5 As shown, the bottom of the clearance groove 301 is provided with multiple mounting grooves 302, which are arranged around the bottom of the clearance groove 301 along the circumference of the shaft core 20. Multiple springs 33 are respectively positioned at one end within each mounting groove 302, and the other end is connected to the annular mounting member 31. This allows the annular mounting member 31, under the elastic force of the multiple springs 33, to drive the annular sealing gasket 32 ​​to tightly seal the oil return gap 23 after the machine tool is shut down and the air supply is cut off. Furthermore, the presence of multiple springs 33 ensures that the annular mounting member 31 is subjected to elastic force along the circumference of the shaft core 20, thereby ensuring that the annular sealing gasket 32 ​​can effectively seal the oil return gap 23 and prevent oil leakage due to localized insufficient force on the annular sealing gasket 32.

[0046] like Figure 1 and Figure 2 As shown, the mounting assembly is equipped with a first air passage 121, which communicates with a first airtight cavity 41. The first air passage 121 is used to introduce airflow into the first airtight cavity 41. When the machine tool is turned on and air is supplied to the first airtight cavity 41, gas is introduced into the first airtight cavity 41 along the first air passage 121, allowing the sealing component to move to the second position under the action of air pressure in the first airtight cavity 41 to open the oil return gap 23. When the oil return gap 23 and the first airtight cavity 41 are connected, the gas entering the first airtight cavity 41 from the first air passage 121 can enter the oil return gap 23 and flow back to the hydraulic station with the hydraulic oil in the oil return cavity 22. After the machine tool is turned off and the air supply is cut off, the first air passage 121 no longer supplies gas to the first airtight cavity 41, and the sealing component can move back to the first position under the action of elastic expansion force, sealing the oil return gap 23 through the annular sealing gasket 32 ​​to prevent oil leakage.

[0047] The airtight cavity also includes a second airtight cavity 42. A second annular flange 311 is provided on the outer periphery of the annular mounting member 31 away from the shaft core 20. The second annular flange 311 and the mounting assembly enclose the second airtight cavity 42. The second airtight cavity 42 is used to move the annular mounting member 31 to the second position when gas is introduced. Thus, based on the first airtight cavity 41, after the machine tool is turned on, in order to ensure that the sealing component can move to the second position to effectively open the return oil gap 23, this embodiment further enhances the pressure of the sealing component to overcome the elastic force of the elastic telescopic member and move to the second position by setting the second airtight cavity 42. This is because if the airflow pressure entering the return oil gap 23 is too high, the return oil path to the hydraulic station will be filled with high-pressure gas, causing the hydraulic oil in the return oil cavity 22 to be unable to return to the hydraulic station. Therefore, under normal circumstances, the pressure of the gas entering the first gas sealing chamber 41 from the first gas passage 121 should not exceed 0.2 MPa (i.e., equal to 0.2 MPa, or slightly less than 0.2 MPa, such as 0.19 MPa, 0.18 MPa, 0.17 MPa, etc.). After the 0.2 MPa gas enters the return oil chamber 22 through the return oil gap 23, the gas can flow back to the hydraulic station together with the hydraulic oil, realizing the return of hydraulic oil. At the same time, after the machine tool is shut down and the gas is cut off, in order to enable the sealing component to move to the first position under the action of the elastic expansion member, so as to achieve tight contact and sealing between the annular sealing gasket 32 ​​and the return oil gap 23, it is also necessary to ensure that the elastic expansion member used, such as the spring 33, has a large elastic force. Therefore, in this embodiment, when the elastic force of the elastic telescopic member is large and the gas pressure entering the first air-sealing cavity 41 is no greater than 0.2 MPa, this embodiment can introduce a gas with a higher pressure (such as gas with a pressure of 0.6 MPa or higher) into the second air-sealing cavity 42. This allows the sealing component to overcome the elastic force and move away from the return oil gap 23 to the second position, thereby ensuring that the annular sealing gasket 32 ​​on the sealing component can completely disengage and open the return oil gap 23. Ultimately, only a pressure of no more than 0.2 MPa flowing out of the first air-sealing cavity 41 is introduced into the return oil gap 23 to effectively pressurize the hydraulic oil to the hydraulic station. This further improves the return oil performance of the hydrostatic spindle, ensuring that the hydraulic oil can be stably and effectively delivered to the hydraulic station. After the machine tool is shut down and the gas supply is cut off, the sealing component can rebound to the first position under the elastic force of the elastic telescopic member to tightly seal the return oil gap 23 and prevent oil leakage.

[0048] like Figure 3As shown, the mounting assembly in this embodiment is further provided with a second air passage 122 and a first groove 123. The second air passage 122 communicates with the bottom of the first groove 123. The second annular flange 311 is at least partially located within the first groove 123 and forms a second airtight cavity 42 with the bottom of the first groove 123. In this embodiment, when the machine tool is started, a high-pressure gas can be introduced into the second airtight cavity 42 through the second air passage 122 to enable the sealing component to overcome the elastic force and move away from the return oil gap 23 to the second position. Furthermore, to enhance the airtightness of the second airtight cavity 42, the sealing component in this embodiment also includes sealing rings 34. There are at least two sealing rings 34, which are disposed between the second annular flange 311 and the sidewall of the first groove 123 and are respectively located on opposite sides of the second annular flange 311 along its own radial direction. The sealing ring 34 is used to seal the installation gap between the second annular flange 311 and the first groove 123, thereby preventing the second air-tight cavity 42 from affecting the effective opening of the oil return gap 23 due to air leakage and / or mutual air leakage with the first air-tight cavity 41.

[0049] like Figure 1 , Figure 3 as well as Figure 4 As shown, the mounting assembly in this embodiment includes a mounting housing 11 and an oil return block 12. The shaft core 20 is mounted inside the mounting housing 11 via a hydrostatic bearing. The oil return block 12 is disposed inside the mounting housing 11, as shown in the figure. Figure 3 and Figure 6 As shown, the oil return block 12 is provided with a mounting hole 124, and the shaft core 20 is at least partially inserted into the mounting hole 124 to form an oil return cavity 22 and an oil return gap 23 between itself and the mounting hole 124. The first air passage 121 and the second air passage 122 are both provided on the oil return block 12. Providing the first air passage 121 and the second air passage 122 on the oil return block 12 reduces the machining difficulty of the first air passage 121 and the second air passage 122. After the oil return block 12 is installed, the first air passage 121 and the second air passage 122 are connected to the corresponding first air-sealing cavity 41 and the second air-sealing cavity 42, which is convenient for machining and has high assembly efficiency.

[0050] like Figure 4 , Figure 6 as well as Figure 7As shown, a third annular flange 125 is provided on the side of the oil return block 12 away from the mounting hole 124. The third annular flange 125 seals against the mounting shell 11 and the annular mounting seat 30. The mounting gap between the third annular flange 125 and the mounting shell 11 and the annular mounting seat 30 can also be sealed by a sealing ring 34, improving the airtightness of the sealing device and ensuring its reliable use. A second groove 126 is provided on the wall of the mounting hole 124, and the second groove 126 and the outer peripheral surface of the shaft core 20 form an oil return cavity 22. A first groove 123 is provided on the oil return block 12 and is located between the second groove 126 and the third annular flange 125. That is, in this embodiment, the first groove 123, the second groove 126, the first air passage 121 and the second air passage 122 can be machined on the annular oil return block 12 in one go, and then sealed against the mounting shell 11 and the annular mounting seat 30 by its third annular flange 125. Simultaneously, the second annular flange 311 of the annular mounting member 31 is at least partially located within the first groove 123 and forms a second airtight cavity 42 between it and the bottom of the first groove 123. The overall structure is easy to process and quick to assemble. In addition, a fourth annular flange 127 is formed between the first groove 123 and the second groove 126, and the oil return gap 23 is located between the fourth annular flange 127 and the outer peripheral surface of the shaft core 20. Specifically, the fourth annular flange 127 is arranged opposite to the first annular flange 21 of the shaft core 20 and is clearance-fitted to form an oil return gap 23 between the fourth annular flange 127 and the first annular flange 21. That is, after machining the second groove 126 on the oil return block 12, the oil return block 12 can be installed on the shaft core 20 to obtain the interconnected oil return cavity 22 and oil return gap 23, which greatly reduces the processing and assembly difficulty of the oil return cavity 22 and oil return gap 23. The annular sealing gasket 32 ​​protrudes from the surface of the annular mounting member 31 near the fourth annular flange 127 on the side closest to the oil return gap 23, and forms a first airtight cavity 41 between the sealing member, the fourth annular flange 127, and the annular mounting member 31 when the sealing member moves to the first position. The first airtight cavity 41 and the second airtight cavity 42 are isolated from each other by a sealing ring 34 to prevent air leakage from affecting the opening of the oil return gap 23.

[0051] Therefore, after the hydrostatic spindle provided in this embodiment of the invention is installed on the machine tool, when the machine tool is started:

[0052] Gas at 0.6 MPa can be transmitted to the second air-sealed cavity 42 through the second air passage 122. Under the action of air pressure, the annular mounting part 31 of the sealing component is pressed down to the second position against the elastic force of the spring 33, causing the annular sealing gasket 32 ​​on the annular mounting part 31 to separate from the first annular flange 21 on the shaft core 20 and the fourth annular flange 127 on the oil return block 12. At the same time, gas at 0.2 MPa enters the first air-sealed cavity 41 through the first air passage 121, and then enters the oil return cavity 22 through the oil return gap 23. The gas at 0.2 MPa flows back to the hydraulic station together with the hydraulic oil in the oil return cavity 22.

[0053] When the machine tool is shut down and the air supply is cut off:

[0054] If it is a vertical hydrostatic spindle, since the oil return gap 23 is vertical, if the air in the vertical oil return gap 23 is cut off, not only should it be sealed and blocked, but oil will flow back and leak. To address this, in this embodiment, multiple springs 33 are provided on the side of the annular mounting member 31 away from the oil return gap 23 (the number of springs 33 can be determined according to actual usage requirements, such as four, five, six, eight, etc., and this embodiment does not impose a unique limitation). After the air in the oil return gap 23 is cut off, both the first air-sealing chamber 41 and the second air-sealing chamber 42 lose pressure. The springs 33 push up the annular mounting member 31, causing the annular sealing gasket 32 ​​on the annular mounting member 31 to fit and press tightly against the first annular flange 21 on the shaft core 20 and the fourth annular flange 127 on the oil return block 12, thereby sealing the oil return gap 23 and preventing hydraulic oil from leaking out from the oil return gap 23.

[0055] A second embodiment of the present invention provides a machine tool including a hydrostatic spindle. The structure of the hydrostatic spindle is described in the first embodiment of the present invention, and will not be repeated here.

[0056] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0057] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0058] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hydrostatic spindle, characterized in that, include: The spindle assembly includes a mounting component and a spindle core (20). The mounting component has a mounting hole (124). The spindle core (20) is rotatably mounted in the mounting hole (124). A return oil chamber (22) and a return oil gap (23) are provided between the outer peripheral surface of the spindle core (20) and the inner wall surface of the mounting hole (124). The return oil gap (23) is located on one side of the return oil chamber (22) along the axial direction of the spindle core (20) and communicates with the return oil chamber (22). The return oil gap (23) is used to allow the hydraulic oil in the return oil chamber (22) to flow back to the hydraulic station in the ventilated state. The sealing device includes an annular mounting seat (30), a sealing component, and an elastic telescopic component. The annular mounting seat (30) is sleeved on the shaft core (20) and connected to the mounting assembly. The sealing component is connected to the side of the annular mounting seat (30) near the oil return gap (23) through the elastic telescopic component and forms an airtight cavity between it and the mounting assembly. The sealing component has a first position where it moves to block the oil return gap (23) under the action of the elastic telescopic force, and a second position where it moves away from the oil return gap (23) when gas is introduced into the gas-tight cavity; The airtight cavity includes a first airtight cavity (41), and the sealing component includes: Annular mounting part (31), the annular mounting part (31) is sleeved on the shaft core (20), and the side of the annular mounting part (31) away from the oil return gap (23) is connected to the elastic expansion member; An annular sealing gasket (32) is disposed on the annular mounting member (31) near the oil return gap (23). The annular sealing gasket (32) is used to block the oil return gap (23) when the sealing member moves to the first position, and forms a first airtight cavity (41) between the annular mounting member (31) and the mounting assembly. The first airtight cavity (41) communicates with the oil return gap (23) after the annular sealing gasket (32) moves to the second position. The shaft core (20) is provided with a first annular flange (21), which is in clearance fit with the inner wall of the mounting hole (124) to form the oil return gap (23), and the projection of the oil return gap (23) along the axial direction of the shaft core (20) is located on the annular sealing gasket (32). The mounting assembly is provided with a first air passage (121), which is connected to the first airtight cavity (41). The first air passage (121) is used to introduce airflow into the first airtight cavity (41). The gas-tight cavity further includes a second gas-tight cavity (42). A second annular flange (311) is provided on the outer periphery of the annular mounting member (31) away from the shaft core (20). The second annular flange (311) and the mounting assembly form the second gas-tight cavity (42). The second gas-tight cavity (42) is used to move the annular mounting member (31) to the second position when gas is introduced.

2. The hydrostatic spindle according to claim 1, characterized in that, The mounting assembly is also provided with a second air passage (122) and a first groove (123). The second air passage (122) is connected to the bottom of the first groove (123). The second annular flange (311) is at least partially located in the first groove (123) and forms a second airtight cavity (42) between it and the bottom of the first groove (123).

3. The hydrostatic spindle according to claim 2, characterized in that, The sealing component further includes: The sealing ring (34) includes at least two sealing rings (34), which are disposed between the sidewalls of the second annular flange (311) and the first groove (123) and are respectively located on opposite sides of the second annular flange (311) along its own radial direction. The sealing ring (34) is used to seal the installation gap between the second annular flange (311) and the first groove (123).

4. The hydrostatic spindle according to any one of claims 2 to 3, characterized in that, The installation components include: Mounting housing (11), the shaft core (20) is mounted inside the mounting housing (11) by a hydrostatic bearing; Oil return block (12), the oil return block (12) is disposed in the mounting shell (11), the oil return block (12) is provided with the mounting hole (124), the shaft core (20) is at least partially inserted into the mounting hole (124) to form the oil return cavity (22) and the oil return gap (23) between the shaft core (20) and the mounting hole (124), and the first air passage (121) and the second air passage (122) are both disposed on the oil return block (12).

5. The hydrostatic spindle according to claim 4, characterized in that, The oil return block (12) is provided with a third annular flange (125) on the side away from the mounting hole (124). The third annular flange (125) seals against the mounting shell (11) and the annular mounting seat (30). A second groove (126) is provided on the hole wall of the mounting hole (124). The second groove (126) and the outer peripheral surface of the shaft core (20) form the oil return cavity (22). The first groove (123) is provided on the oil return block (12) and located between the second groove (126) and the third annular flange (125).

6. The hydrostatic spindle according to claim 5, characterized in that, A fourth annular flange (127) is formed between the first groove (123) and the second groove (126), and the oil return gap (23) is located between the fourth annular flange (127) and the outer peripheral surface of the shaft core (20); wherein, the annular sealing gasket (32) protrudes from the surface of the annular mounting member (31) near the fourth annular flange (127) on the side near the oil return gap (23), and forms the first airtight cavity (41) between the sealing member and the fourth annular flange (127) and the annular mounting member (31) when the sealing member moves to the first position.

7. A machine tool, characterized in that, The machine tool includes the hydrostatic spindle as described in any one of claims 1 to 6.

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