Hydrostatic spindle structure and machine tool having the same

Abstract

The application discloses a kind of static pressure spindle structures and the machine tool with it.The static pressure spindle structure and the machine tool with it include main body component, spindle and sealing component, main body component is equipped with oil return channel, gas seal channel and connecting channel;Spindle is rotatably arranged on main body component, and the outer surface of spindle and the inner wall surface of main body component have oil return cavity, along the radial direction of spindle, gas seal channel is respectively arranged in the two sides of oil return cavity, and the oil return channel is communicated with oil return cavity by connecting channel;Sealing component includes elastic element and seal, the two ends of elastic element are respectively abutted between connecting channel and seal, and seal can be abutted by elastic element to block connecting channel or be opened by the pressure of gas flow transmission in oil return cavity to connect channel.The application can solve the problem that residual hydraulic oil on static pressure spindle is prone to overflow and oil leakage due to residual hydraulic oil and insufficient oil return pressure and other reasons in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical processing, in particular to a static pressure spindle structure and a machine tool with the same. BACKGROUND

[0002] The static pressure spindle is a kind of spindle structure supported by liquid static pressure instead of traditional rolling support. It is widely used in spindle design because of its high rotation accuracy, strong anti-vibration ability and low friction power. In the design of static pressure structure, the design of the internal oil circuit of the spindle as a key link of the oil supply system affects the actual production and application.

[0003] Among them, the design of the oil return channel affects the normal circulation of hydraulic oil, the stability of oil pressure, the temperature rise of hydraulic oil, the cooling of the static pressure system and the overflow and leakage of oil. The overflow and leakage of oil is often ignored by designers, but it brings many troubles to actual production operation. Especially for the vertical operation of the spindle structure, the main reasons are the residual hydraulic oil in the oil return channel, insufficient oil return pressure and poor sealing effect. Therefore, the present application provides a one-way oil return channel structure applied to the internal static pressure spindle to solve the problem of residual hydraulic oil in the static pressure spindle. SUMMARY

[0004] The main purpose of the present application is to provide a static pressure spindle structure which can solve the problem of residual hydraulic oil in the static pressure spindle which is prone to overflow and leakage due to residual hydraulic oil and insufficient oil return pressure and the like in the prior art.

[0005] According to one aspect of the present application, a static pressure spindle structure is provided, comprising:

[0006] A main body part, wherein an oil return channel, an air seal channel and a connecting channel are arranged on the main body part;

[0007] A spindle rotatably arranged in the main body part, wherein an oil return cavity is formed between the outer surface of the spindle and the inner wall surface of the main body part, the air seal channel is arranged on both sides of the oil return cavity along the radial direction of the spindle, and the connecting channel is in communication between the oil return channel and the oil return cavity;

[0008] A sealing part, wherein the sealing part comprises an elastic element and a sealing part, and the two ends of the elastic element are respectively abutted between the connecting channel and the sealing part;

[0009] The sealing part has a first position where the abutting force applied by the elastic element blocks the connecting channel, and a second position where the pressure transmitted by the airflow in the air seal channel overcomes the abutting force applied by the elastic element to open the connecting channel.

[0010] Further, the main body component comprises:

[0011] a shaft sleeve, a through hole being arranged in the shaft sleeve;

[0012] a first end cover, the first end cover being arranged at a first end of the shaft sleeve, and a first mounting hole being arranged on the first end cover, the first mounting hole being coaxially arranged with the through hole;

[0013] a second end cover, the second end cover being arranged at a second end of the shaft sleeve, and a second mounting hole being arranged on the second end cover, the second mounting hole being coaxially arranged with the through hole;

[0014] wherein the main shaft is arranged in the first mounting hole, the through hole and the second mounting hole.

[0015] Further, the oil return channel comprises a first channel segment and a second channel segment which are in communication with each other, the first channel segment is arranged on the shaft sleeve and extends in a direction parallel to the axis of the shaft sleeve, and the second channel segment is arranged on the first end cover and / or the second end cover and extends in a direction parallel to the axis of the shaft sleeve.

[0016] Further, an annular flange is arranged on the main shaft, an annular recess is arranged on the inner wall surface of the end of the through hole close to the second end cover, the second end cover and the annular recess form an annular groove, the annular flange is located in the annular groove and gap fits with the annular groove to form the oil return cavity.

[0017] Further, the connecting channel is arranged on the shaft sleeve and penetrates the shaft sleeve and the oil return channel in the radial direction of the shaft sleeve, and the oil return channel separates the connecting channel into a blocking segment and a communication segment, the communication segment is closer to the oil return cavity than the blocking segment, a blocking member is arranged in the blocking segment, and the sealing component is arranged between the blocking segment and the communication segment.

[0018] Further, a tapered opening is arranged at the end of the communication segment away from the oil return cavity, the cross-sectional area of the tapered opening gradually increases in the direction away from the oil return cavity, and a frustum segment is arranged on the sealing part which is matched with the tapered opening.

[0019] Further, the inner wall surface of the tapered opening is a tapered surface, and the included angle between the tapered surface and the axis of the communication segment is 25° to 35°.

[0020] Further, the blocking member comprises a sealing screw; and / or,

[0021] the elastic element comprises a spring or an elastic rubber column; and / or,

[0022] The sealing part comprises a sealing cover or a sealing column.

[0023] Further, the main shaft and the main body part have a first gap, the main body part is provided with an annular channel on the side surface close to the main shaft, the annular channel is coaxially arranged with the main shaft, the first gap is connected between the annular channel and the oil return cavity, and the first gap and the annular channel form the gas seal channel, and the main body part is provided with an air inlet communicating with the gas seal channel.

[0024] Further, the application also provides a machine tool comprising the hydrostatic spindle structure.

[0025] In the application, according to whether the spindle is in a working state, the hydrostatic spindle structure can be divided into two cases of working state and non-working state. When the spindle stops working, the hydrostatic spindle structure is in the non-working state, no high-pressure gas is introduced into the gas seal channel, at this time, the pressure in the oil return channel is consistent with that in the oil return cavity, the sealing part is in the first position under the abutting force exerted by the elastic element to block the connecting channel. When the spindle works, the hydrostatic spindle structure is in the working state, high-pressure gas is introduced into the gas seal channel, the high-pressure gas in the gas seal channel flows to the oil return cavity to exert pressure on the oil in the oil return cavity, at this time, the pressure of the oil in the oil return cavity increases, and then the pressure can be exerted on the sealing part, when the pressure of the oil in the oil return cavity is greater than the pressure exerted by the elastic element on the sealing part, the sealing part can open the connecting channel, the oil in the oil return cavity can enter the oil return channel from the connecting channel, and finally return to the oil supply system of the hydrostatic spindle structure, that is, the sealing part in the embodiment has the second position which is opened by the pressure transmitted by the gas flow in the gas seal channel to overcome the abutting force exerted by the elastic element. It can be seen that the oil in the hydrostatic spindle structure of the application can realize real-time return during the working process of the spindle, and is not easy to remain in the oil return cavity, and the oil overflow phenomenon is not easy to occur when the spindle stops working. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and serve to explain the principles of the application. In the drawings:

[0027] Figure 1 A front view of the hydrostatic spindle structure provided by the application;

[0028] Figure 2 A sectional view in the first direction of the hydrostatic spindle structure provided by the application;

[0029] Figure 3 AFigure 2 enlarged view of area A in FIG. 1B;

[0030] Figure 4 is Figure 3 enlarged view of area B in FIG. 1B;

[0031] Figure 5 is a sectional view of the hydrostatic spindle structure provided by the present application in the second direction;

[0032] Figure 6 is Figure 5 enlarged view of area C in FIG. 1B.

[0033] Wherein, the above-mentioned drawings include the following reference signs:

[0034] 10, main body part; 101, oil return passage; 1011, first passage section; 1012, second passage section; 102, gas seal passage; 103, connecting passage; 1031, blocking section; 1032, communicating section; 1033, tapered opening; 1034, tapered surface; 104, annular passage; 11, first end cover; 111, first mounting hole; 12, second end cover; 121, second mounting hole; 13, shaft sleeve; 131, through hole; 1311, annular recess; 14, spindle; 141, annular flange; 142, first gap; 20, oil return cavity; 30, sealing part; 31, elastic element; 32, sealing portion; 321, frustum section; 40, blocking member. DETAILED DESCRIPTION

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] The foregoing merely illustrates the principles of the application. It will be apparent to those skilled in the art that the scope of the application is not limited to the details of the foregoing description because the scope of the present application is decided by the claims. Various modifications made within the scope of an equivalent of the concepts and technical solutions of the application will be apparent to those skilled in the art. Any feature in the preceding description and accompanying drawings that can be considered as being inventive in itself also constitutes an independent aspect of the present application. Therefore, the scope of protection of this application is not limited to the specific embodiments described herein, but covers all modifications falling within the scope of the claims.

[0038] As mentioned in the background, the existing static pressure spindle is prone to oil overflow and leakage due to residual hydraulic oil in the oil return channel, insufficient oil return pressure, and poor sealing effect, which causes many troubles to actual production operation. Therefore, the present application provides a static pressure spindle structure and a machine tool with the same to solve the problem of easy overflow of residual hydraulic oil on the static pressure spindle.

[0039] Referring to Figures 1 to 6 The present application provides a static pressure spindle structure, which comprises a main body component 10, a spindle 14, and a sealing component 30.

[0040] The main body component 10 is provided with an oil return channel 101, an air sealing channel 102, and a connecting channel 103; the spindle 14 is rotatably arranged in the main body component 10, and the outer surface of the spindle 14 and the inner wall surface of the main body component 10 have an oil return cavity 20; along the radial direction of the spindle 14, the air sealing channel 102 is arranged on both sides of the oil return cavity 20, respectively; the oil return channel 101 and the oil return cavity 20 are communicated through the connecting channel 103; the sealing component 32 comprises an elastic element 31 and a sealing part 32, and the two ends of the elastic element 31 are respectively abutted between the connecting channel 103 and the sealing part 32; wherein the sealing part 32 has a first position subjected to the abutting force of the elastic element 31 to block the connecting channel 103, and the sealing part 32 also has a second position subjected to the pressure transmitted by the airflow in the air sealing channel 102 to overcome the abutting force of the elastic element 31 to open the connecting channel 103.

[0041] When the static pressure spindle structure in the embodiment is actually used, the static pressure spindle structure is divided into two cases of working state and non-working state according to whether the spindle 14 is in working state. When the spindle 14 stops working, the static pressure spindle structure is in non-working state, the high-pressure gas is not introduced into the gas seal channel 102, at this time, the oil return channel 101 is consistent with the pressure in the oil return cavity 20, the sealing part 32 is in the first position by the sealing force of the elastic element 31 to block the connecting channel 103. When the spindle 14 works, the static pressure spindle structure is in working state, the high-pressure gas is introduced into the gas seal channel 102, the high-pressure gas in the gas seal channel 102 flows to the oil return cavity 20 to apply pressure to the oil in the oil return cavity 20, at this time, the pressure of the oil in the oil return cavity 20 increases, and then the pressure can be applied to the sealing part 32, when the pressure of the oil in the oil return cavity 20 is greater than the pressure of the sealing part 32 applied by the elastic element 31, the sealing part 32 can open the connecting channel 103, the oil in the oil return cavity 20 can enter the oil return channel 101 from the connecting channel 103, and finally return to the oil supply system of the static pressure spindle structure, that is, the sealing part 32 in the embodiment has the second position of opening the connecting channel 103 by the pressure transferred by the gas flow in the gas seal channel 102 to overcome the sealing force of the elastic element 31. It can be seen that the oil of the static pressure spindle structure of the application can realize real-time return during the working process of the spindle 14, and is not easy to remain in the oil return cavity 20, and the oil overflow phenomenon is not easy to occur when the spindle 14 stops working.

[0042] At the same time, since the oil return cavity 20 of the application is provided with the gas seal channel 102 on both sides, the high-pressure gas is introduced into the gas seal channel 102 when the static pressure spindle structure works, which can seal the oil in the oil return cavity 20 and transport the oil in the oil return cavity 20 to the oil return channel 101 for recycling.

[0043] In the embodiment, when the hydrostatic spindle structure is actually used, the hydrostatic spindle structure can realize real-time backflow of oil according to whether the spindle 14 is in a working state. To realize the real-time backflow function of the oil, the main body component 10 is provided with an oil return channel 101, an air seal channel 102 and a connecting channel 103. That is, to connect the oil return cavity 20 and the oil return channel 101, the connecting channel 103 is arranged between the oil return channel 101 and the oil return cavity 20. To enable the oil in the oil return cavity 20 to open the sealing part 32 and flow into the oil return channel 101, the air seal channel 102 is arranged on both sides of the oil return cavity 20 to introduce high-pressure gas to increase the pressure of the oil in the oil return cavity 20. To enable the sealing part 32 to realize the function of automatic closing, the sealing component 30 includes two parts of an elastic element 31 and a sealing part 32, wherein the sealing part 32 can block the connecting channel 103 to prevent the oil in the oil return channel 101 from flowing to the oil return cavity 20 and causing overflow; and the elastic element 31 can stretch and contract according to whether the sealing part 32 is subjected to pressure, so as to realize the blocking of the connecting channel 103 by the sealing part 32.

[0044] Further, the main body component 10 in the embodiment includes a shaft sleeve 13, a first end cover 11 and a second end cover 12. The shaft sleeve 13 is provided with a through hole 131; the first end cover 11 is arranged at a first end of the shaft sleeve 13, and the first end cover 11 is provided with a first mounting hole 111 coaxially arranged with the through hole 131; the second end cover 12 is arranged at a second end of the shaft sleeve 13, and the second end cover 12 is provided with a second mounting hole 121 coaxially arranged with the through hole 131; wherein the spindle 14 is arranged in the first mounting hole 111, the through hole 131 and the second mounting hole 121. That is, the main body component 10 in the embodiment includes the shaft sleeve 13, the first end cover 11 and the second end cover 12 arranged in a split manner rather than an integral molding structure, which is beneficial to the maintenance and cleaning of the hydrostatic spindle 14 structure in the later stage, and is also beneficial to the processing and maintenance of the connecting channel 103 and the sealing part 32 on the main body component 10.

[0045] Further, in order to ensure that the oil can flow back to the oil supply system smoothly, the oil return channel 101 in the embodiment comprises a first channel segment 1011 and a second channel segment 1012 which are in communication with each other, the first channel segment 1011 is arranged on the shaft sleeve 13 and extends in a direction parallel to the axis of the shaft sleeve 13, and the second channel segment 1012 is arranged on the first end cover 11 and / or the second end cover 12 and extends in a direction parallel to the axis of the shaft sleeve 13. That is to say, in the embodiment, by designing the oil return channel 101 to comprise the first channel segment 1011 and the second channel segment 1012 which are in communication with each other and both of which extend in a direction parallel to the axis of the shaft sleeve 13, not only is the processing and manufacturing convenient, but also the practicability of the present application can be improved. At the same time, the first channel segment 1011 arranged on the shaft sleeve 13 and the second channel segment 1012 arranged on the first end cover 11 and / or the second end cover 12 in the embodiment can be processed separately from the first channel segment 1011, which can reduce the production cost of the static pressure spindle structure in the embodiment. Of course, in other embodiments of the present application, the oil return channel 101 can also extend in other directions, as long as other deformation modes that can transport the oil in the oil return cavity 20 to the oil supply system of the static pressure spindle structure are within the protection scope of the present application.

[0046] Further, the main shaft 14 in the embodiment is provided with an annular flange 141, and the inner wall surface of the one end of the through hole 131 close to the second end cover 12 is provided with an annular recess 1311, the second end cover 12 and the annular recess 1311 form an annular groove, and the annular flange 141 is located in the annular groove and gap fits with the annular groove to form the oil return cavity 20. That is to say, in order to solve the problem of limited space in the oil circuit design of the static pressure spindle 14, in the actual processing and production process, only the main shaft 14 needs to be installed in the shaft sleeve 13, and then the second end cover 12 is butt-jointed with the shaft sleeve 13, and the main shaft 14, the shaft sleeve 13 and the second end cover 12 can form the oil return cavity 20 described above, which is simple in structure and easy to realize.

[0047] Further, the connecting channel 103 in the embodiment is arranged on the shaft sleeve 13 and penetrates the shaft sleeve 13 and the oil return channel 101 in the radial direction of the shaft sleeve 13, and the oil return channel 101 separates the connecting channel 103 into the blocking section 1031 and the communicating section 1032, the communicating section 1032 is closer to the oil return cavity 20 than the blocking section 1031, the blocking member 40 is arranged in the blocking section 1031, and the sealing part 30 is arranged between the blocking section 1031 and the communicating section 1032. In actual processing of the connecting channel 103, a hole can be punched on the outer circumferential surface of the shaft sleeve 13 in the radial direction of the shaft sleeve 13 to form the connecting channel 103, the connecting channel 103 penetrates the oil return channel 101 to realize the communication between the connecting channel 103 and the oil return channel 101, at the same time, the other end of the connecting channel 103 extends to the oil return cavity 20, thereby facilitating the communication between the connecting channel 103 and the oil return cavity 20, after processing, the oil return channel 101 can separate the connecting channel 103 into the blocking section 1031 and the communicating section 1032 as described above, at this time, the blocking member 40 as described above is arranged in the blocking section 1031, thereby facilitating the blocking of the side of the connecting channel away from the oil return cavity 20. That is to say, the arrangement of the connecting channel 103 in the embodiment is more suitable for machining. Alternatively, the blocking member 40 in the embodiment can be a blocking screw, a blocking top screw, a blocking rubber plug or the like structure, as long as other deformation modes under the concept of the application, which are within the protection scope of the application.

[0048] Further, in order to make the sealing part 32 have a better sealing effect on the communicating section 1032, the end of the communicating section 1032 away from the oil return cavity 20 is provided with a tapered opening 1033 in the embodiment, the cross-sectional area of the tapered opening 1033 gradually increases in the direction away from the oil return cavity 20, and the tapered section 321 matched with the tapered opening 1033 is arranged on the sealing part 32. In actual work, the sealing part 32 can move towards the direction of the tapered opening 1033 under the abutting force applied by the elastic element 31, at this time, the arrangement of the tapered opening 1033 can give a good guiding effect to the insertion of the sealing part 32, thereby facilitating the sealing part 32 to block the end of the communicating section 1032, so as to prevent the oil from flowing between the oil return channel 101 and the oil return cavity 20.

[0049] Of course, in other embodiments of the application, the opening of the end of the communicating section 1032 away from the oil return cavity 20 can also be an opening with no change in cross-sectional area, as long as the sealing part 32 can block the communicating section 1032.

[0050] Further, the inner wall surface of the tapered opening 1033 in the embodiment is a tapered surface 1034, and the included angle between the tapered surface 1034 and the axis of the communication section 1032 is 25° to 35°, for example, 25°, 28°, 30°, 32°, or 35°. When the included angle between the tapered surface 1034 and the axis of the communication section 1032 is less than 25°, the sealing part 32 is not convenient to insert into the communication section 1032, and when the included angle between the tapered surface 1034 and the axis of the communication section 1032 is greater than 35°, the sealing part 32 has a poor plugging effect on the tapered opening 1033.

[0051] Optionally, the elastic element 31 in the embodiment includes a spring or an elastic rubber column, which can realize the second position that the sealing part 32 is opened to the connecting channel 103 under the pressure of the airflow transmitted in the gas seal channel 102 to overcome the abutting force exerted by the spring or the elastic rubber column. The structure is simple and convenient to realize. Of course, in other embodiments of the application, the elastic element 31 can also be an elastic pad or the like structure, as long as it is other deformation modes under the concept of the application, which are within the protection scope of the application.

[0052] Optionally, the sealing part 32 in the embodiment includes a sealing cover or a sealing column, which is matched with the tapered opening 1033 of the communication section 1032, and is convenient to plug the communication section 1032.

[0053] Further, the main shaft 14 and the main body part 10 have a first gap 142 in the embodiment, the side surface of the main body part 10 close to the main shaft 14 is provided with an annular channel 104, the annular channel 104 is coaxially arranged with the main shaft 14, the first gap 142 is connected between the annular channel 104 and the oil return cavity 20, and the first gap 142 and the annular channel 104 form the gas seal channel 102 described above. The main body part 10 is provided with an air inlet (not shown in the figure) communicated with the gas seal channel 102. In the embodiment, the annular channel 104 is arranged on the main body part 10, and after the main shaft 14 is installed in the main body part 10, the main shaft 14 and the main body part 10 have the first gap 142. At this time, the first gap 142 and the annular channel 104 together constitute the gas seal channel 102 described above, that is to say, when the actual static pressure spindle structure is processed, only an annular channel 104 needs to be processed in the inside of the main body part 10, and an air inlet communicated with the annular channel 104 needs to be processed in the radial direction of the main body part 10, so that the high-pressure gas can be introduced into the gas seal channel 102, and the structure is simple and convenient to realize.

[0054] On the other hand, the application also provides a machine tool, which includes the static pressure spindle structure described above, and therefore, the machine tool includes all the technical effects of the static pressure spindle structure. Since the technical effects of the static pressure spindle structure have been described in detail above, they will not be described here again.

[0055] For purposes of the description hereinafter, spatial relative terms, such as "above", "below", "upper", "lower", and the like, can be used to describe the relative position of one device or feature to another as illustrated in the figures. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, then a dependent "above" or "up" can be oriented "below" or "down" in the inverted orientation. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative terms used herein interpreted accordingly.

[0056] In addition, it should be noted that the use of "first", "second", and the like, herein does not imply that there are only two of these items nor that these items must be in a particular order. These designations are used herein for the convenience of the reader to identify the different components of the application.

[0057] The preferred embodiments of the application are shown and described above. However, the application can be modified in various ways without departing from the spirit and scope of the application. Accordingly, the scope of the application should not be limited to the above described embodiments.

Claims

1. A hydrostatic spindle structure, characterized in that, include: The main body component (10) is provided with an oil return channel (101), an air-tight channel (102) and a connecting channel (103); A main shaft (14) is rotatably mounted on the main body component (10), and an oil return cavity (20) is provided between the outer surface of the main shaft (14) and the inner wall surface of the main body component (10). Along the radial direction of the main shaft (14), the air-tight channels (102) are respectively provided on both sides of the oil return cavity (20), and the oil return channels (101) and the oil return cavity (20) are connected through the connecting channel (103). A sealing component (30) includes an elastic element (31) and a sealing portion (32), wherein the two ends of the elastic element (31) abut against the connection channel (103) and the sealing portion (32), respectively. The sealing part (32) has a first position where the connecting channel (103) is blocked by the pushing force applied by the elastic element (31), and the sealing part (32) also has a second position where the connecting channel (103) is opened by the pressure transmitted by the airflow in the airtight channel (102) to overcome the pushing force applied by the elastic element (31).

2. The hydrostatic spindle structure according to claim 1, characterized in that, The main body component (10) includes: A bushing (13) having a through hole (131) inside; The first end cap (11) is disposed at the first end of the bushing (13), and the first end cap (11) is provided with a first mounting hole (111), which is coaxially disposed with the through hole (131). The second end cap (12) is disposed at the second end of the bushing (13). The second end cap (12) is provided with a second mounting hole (121), which is coaxially disposed with the through hole (131). The main shaft (14) passes through the first mounting hole (111), the through hole (131), and the second mounting hole (121).

3. The hydrostatic spindle structure according to claim 2, characterized in that, The oil return channel (101) includes a first channel section (1011) and a second channel section (1012) that are interconnected. The first channel section (1011) is disposed on the bushing (13) and extends in a direction parallel to the axis of the bushing (13). The second channel section (1012) is disposed on the first end cap (11) and / or the second end cap (12) and extends in a direction parallel to the axis of the bushing (13).

4. The hydrostatic spindle structure according to claim 2, characterized in that, The main shaft (14) is provided with an annular flange (141), and an annular recess (1311) is provided on the inner wall surface of the through hole (131) near the second end cover (12). The second end cover (12) and the annular recess (1311) surround each other to form an annular groove. The annular flange (141) is located in the annular groove and is in clearance fit with the annular groove to form the oil return chamber (20).

5. The hydrostatic spindle structure according to claim 2, characterized in that, The connecting channel (103) is disposed on the bushing (13) and passes through the bushing (13) and the oil return channel (101) in the radial direction of the bushing (13). The oil return channel (101) divides the connecting channel (103) into a blocking section (1031) and a connecting section (1032). The connecting section (1032) is closer to the oil return chamber (20) than the blocking section (1031). A blocking component (40) is disposed in the blocking section (1031). The sealing component (30) is disposed between the blocking section (1031) and the connecting section (1032).

6. The hydrostatic spindle structure according to claim 5, characterized in that, The connecting section (1032) is provided with a conical opening (1033) at one end away from the oil return chamber (20). The cross-sectional area of ​​the conical opening (1033) gradually increases in the direction away from the oil return chamber (20). The sealing part (32) is provided with a frustum section (321) that is adapted to the conical opening (1033).

7. The hydrostatic spindle structure according to claim 6, characterized in that, The inner wall surface of the conical opening (1033) is a conical surface (1034), and the angle between the conical surface (1034) and the axis of the connecting segment (1032) is 25° to 35°.

8. The hydrostatic spindle structure according to claim 5, characterized in that, The sealing element (40) includes a sealing screw; and / or, The elastic element (31) includes a spring or an elastic rubber column; and / or, The sealing part (32) includes a sealing cap or a sealing post.

9. The hydrostatic spindle structure according to any one of claims 1 to 8, characterized in that, There is a first gap (142) between the main shaft (14) and the main body component (10). An annular channel (104) is provided on the side of the main body component (10) near the main shaft (14). The annular channel (104) is coaxially arranged with the main shaft (14). The first gap (142) connects the annular channel (104) and the oil return chamber (20). The first gap (142) and the annular channel (104) form the air-tight channel (102). An air inlet communicating with the air-tight channel (102) is provided on the main body component (10).

10. A machine tool, characterized in that, The machine tool includes the hydrostatic spindle structure as described in any one of claims 1 to 9.

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