A main shaft end gas seal assembly and motorized spindle

Abstract

The application provides a main shaft end gas seal assembly and an electric spindle. The main shaft end gas seal assembly comprises a mandrel, a bearing locking piece, a bearing gland, an end cover and an air inlet channel. The bearing locking piece is arranged on the outer periphery of the mandrel. At least part of the structure of the bearing gland and at least part of the structure of the end cover are arranged on the outer periphery of the part of the structure of the bearing locking piece. A first annular cavity and a first annular gap are arranged between the axial end of the bearing gland facing the end cover and the axial end of the end cover facing the bearing gland. The radial inner end of the first annular gap is in communication with a second annular gap. The radial outer end of the first annular gap is in communication with the first annular cavity. The flow cross-sectional area of the first annular cavity is larger than that of the first annular gap. The air inlet channel can introduce gas into the first annular cavity. According to the application, the uniformity of the circumferential air curtain is improved, thereby enhancing the sealing effect of the electric spindle and solving the problem of uneven circumferential air pressure of the main shaft front end gas seal gap.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of main shaft, in particular to a main shaft end gas seal assembly and an electric main shaft. BACKGROUND

[0002] Most of the machining center main shafts use precision grade and super-precision grade rolling bearings. In order to protect the bearings from the damage of water, oil and chip pollutants in machining, the front end of the main shaft must use a sealing structure to avoid the entry of pollutants and the corrosion of the bearings, thereby reducing the service life of the main shaft.

[0003] Most of the existing main shaft gas seal structures use a gas seal ring to generate a circumferential gas curtain. A limited number of uniformly distributed radial gas holes are formed in the circumferential direction of the gas seal ring, so that the sealing gas enters the sealing gap from the gas holes. The circumferential gas curtain formed by this gas seal ring structure is limited in gas pressure uniformity due to the limited number of gas holes. The gas seal ring is generally made of brass, and the gas hole diameter is very small, which has high processing cost. At the same time, the gas seal ring needs to be applied with an interference amount to be embedded in the stationary assembly, which has great assembly difficulty.

[0004] Due to the technical problems of the non-uniform circumferential gas pressure of the main shaft front end gas seal gap in the prior art, the present application researches and designs a main shaft end gas seal assembly and an electric main shaft. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the defect of the non-uniform circumferential gas pressure of the main shaft front end gas seal gap in the prior art, thereby providing a main shaft end gas seal assembly and an electric main shaft.

[0006] In order to solve the above problems, the present application provides a main shaft end gas seal assembly, which comprises:

[0007] a mandrel, a bearing locking piece, a bearing gland, an end cover and an air inlet channel, the bearing locking piece is arranged on the outer periphery of the mandrel to rotate integrally with the mandrel, at least part of the structure of the bearing gland and at least part of the structure of the end cover are arranged on the outer periphery of the part of the structure of the bearing locking piece, the end cover and the bearing gland have at least part of the structure in contact in the axial direction, and there is a second annular gap between the outer periphery of the bearing locking piece and the inner periphery of the bearing gland;

[0008] a first annular cavity and a first annular gap are arranged between the axial end of the bearing gland facing the end cover and the axial end of the end cover facing the bearing gland, the radial inner end of the first annular gap is in communication with the second annular gap, the radial outer end of the first annular gap is in communication with the first annular cavity, the flow cross-sectional area of the first annular cavity is larger than that of the first annular gap, and the air inlet channel can introduce gas into the first annular cavity.

[0009] In some embodiments,

[0010] The second annular gap further extends between the outer periphery of the bearing lock and the inner periphery of the end cover; the first annular cavity is a cavity formed by recessing an axial end surface of the bearing gland facing the end cover in a direction away from the end cover, the first annular cavity is an annular cavity surrounding the mandrel in a circumferential direction, the first annular gap is an annular gap surrounding the mandrel in a circumferential direction, the axial height of the first annular cavity is higher than the axial height of the first annular gap, and the radial length of the first annular cavity is greater than or equal to the radial length of the first annular gap.

[0011] In some embodiments,

[0012] Further comprising a cover plate, the cover plate is disposed at an axial end of the end cover away from the bearing gland and fixedly connected with the end cover, a radially inner portion of the cover plate extends to be axially opposite to the bearing lock, and a first tortuous gap is provided between the radially inner portion of the cover plate and the bearing lock, a radially inner end of the cover plate has a fitting gap with the mandrel, the fitting gap is in communication with the first tortuous gap, and the first tortuous gap can change the flow direction of fluid flowing into the first tortuous gap through the fitting gap more than once.

[0013] In some embodiments,

[0014] An end of the first tortuous gap away from the fitting gap is in communication with the second annular gap, and gas entering the second annular gap through the first annular cavity can enter the first tortuous gap to prevent fluid at the fitting gap from flowing into the second annular gap.

[0015] In some embodiments,

[0016] At least one protruding structure is provided on the axial end surface of the bearing locking member facing the cover plate, and the protruding structure protrudes in the direction of the bearing locking member; at least one recess structure is provided on the axial end surface of the bearing locking member facing the cover plate, and the recess structure is recessed in the direction away from the cover plate; the protruding structure can be inserted into the recess structure; a second axial gap is formed between the top of the protruding structure and the bottom of the recess structure; a first radial gap is formed between the radial inner end of the protruding structure and the radial inner end of the recess structure; a second radial gap is formed between the radial outer end of the protruding structure and the radial outer end of the recess structure; the recess structure is located between the radial inner end and the radial outer end of the bearing locking member; the part between the radial inner end of the bearing locking member and the recess structure has a first axial gap with the cover plate in the axial direction; the part between the radial outer end of the bearing locking member and the recess structure has a third axial gap with the cover plate in the axial direction; the first tortuous gap includes the first axial gap, the first radial gap, the second axial gap, the second radial gap and the third axial gap.

[0017] In some embodiments,

[0018] A sump is provided at the radial inner end of the end cover, and a drain hole is provided at the radial outer end of the bearing locking member; the sump and the drain hole are in communication through the second annular gap; a drain passage is further provided in the end cover, and one end of the drain passage is in communication with the sump, and the other end of the drain passage is in communication with the outside of the end cover.

[0019] In some embodiments,

[0020] The sump is a recess structure provided at the radial inner end surface of the end cover and formed in the direction away from the bearing locking member; the drain hole is a recess structure provided at the radial outer end surface of the bearing locking member and formed in the direction away from the end cover; the sump is an annular structure; the drain hole is a plurality of hole structures arranged in a circumferential direction; the drain hole is in communication with the first tortuous gap; the radial inner end of the drain passage is in communication with the sump, and the radial outer end of the drain passage extends to the radial outer periphery of the end cover.

[0021] In some embodiments,

[0022] The sump is arranged at a position close to the first tortuous gap relative to the first annular gap in the axial direction; the drain passage is a straight passage, and the central axis of the drain passage is not perpendicular to the central axis of the mandrel; when the central axis of the mandrel extends in the vertical direction, the height of the radial outer end of the drain passage is lower than the height of the radial inner end of the drain passage.

[0023] In some embodiments,

[0024] The cover plate and the end cap are fixed by threaded fasteners; an axial end of the mandrel is connected with a tool shank, and the tool shank and the cover plate are arranged at the axial end of the mandrel.

[0025] In some embodiments,

[0026] Further comprising a bearing arranged at the outer periphery of the mandrel to support the mandrel, and a bearing locking member capable of acting on an axial end of an inner ring of the bearing.

[0027] In some embodiments,

[0028] The gas inlet channel comprises a second gas inlet passage and a third gas inlet passage arranged inside the bearing pressure cover, one end of the third gas inlet passage is in communication with the first annular cavity, the third gas inlet passage is in communication between the second gas inlet passage and the first annular cavity, the extension direction of the second gas inlet passage is not parallel to the extension direction of the third gas inlet passage, and the angle between them is between (0, 90];

[0029] Further comprising a bearing seat arranged at the outer periphery of the bearing to support the bearing, and the gas inlet channel further comprises a first gas inlet passage arranged inside the bearing seat, an axial end of the bearing seat is connected with the bearing pressure cover, one end of the first gas inlet passage can be in communication with the second gas inlet passage, and the other end can introduce gas.

[0030] In some embodiments,

[0031] The gas inlet channel further comprises a fourth gas inlet passage arranged on the bearing pressure cover, the fourth gas inlet passage is in communication between the first gas inlet passage and the second gas inlet passage, the first gas inlet passage and the fourth gas inlet passage are both straight passages, and their central axes coincide and are arranged parallel to the axis of the mandrel, the second gas inlet passage is also a straight passage, and its central axis is perpendicular to the central axis of the fourth gas inlet passage, and the third gas inlet passage is also a straight passage, and its central axis is perpendicular to the central axis of the second gas inlet passage.

[0032] In some embodiments,

[0033] The radially inner side of the axial end of the bearing pressure cover away from the end cap is in axial connection with the outer ring of the bearing; the radially outer end of the second gas inlet passage penetrates to the radially outer peripheral surface of the bearing pressure cover, and a plug is arranged at the radially outer end of the second gas inlet passage; the outer periphery of the bearing seat is further provided with a bearing sleeve.

[0034] In some embodiments,

[0035] Further comprising a seal arranged on the outer periphery of the mandrel to rotate integrally with the mandrel and to act on the axial one end of the inner ring of the bearing, the seal being arranged between the axial one end of the inner ring of the bearing and the bearing locking member, the bearing locking member exerting a fastening force on the inner ring of the bearing through the seal.

[0036] In some embodiments,

[0037] The part structure of the bearing gland opposite to the seal in the radial direction is provided with a first protrusion protruding in the direction of the seal, the seal is provided with a second protrusion protruding in the direction of the bearing gland, a second tortuous gap is formed between the first protrusion and the second protrusion, a second annular cavity is formed between the first protrusion and the bearing locking member, the radial outer end of the second annular cavity communicates with the second annular gap, and the radial inner end of the second annular cavity communicates with the second tortuous gap.

[0038] In some embodiments,

[0039] The first protrusion and the second protrusion are arranged opposite in the axial direction, the first protrusion is provided with at least two first protruding ribs in the direction of the second protrusion, a first recess is formed between two adjacent first protruding ribs, the second protrusion is provided with at least two second protruding ribs in the direction of the first protrusion, a second recess is formed between two adjacent second protruding ribs, the first protruding ribs and the second recesses are inserted and matched, and a first gas gap is formed, the second protruding ribs and the first recesses are inserted and matched, and a second gas gap is formed, and the second tortuous gap includes the first gas gap and the second gas gap.

[0040] The application further provides an electric spindle comprising the spindle shaft end gas seal assembly.

[0041] The spindle shaft end gas seal assembly and the electric spindle provided by the application have the following beneficial effects:

[0042] 1. The present application is characterized in that a first annular cavity and a first annular gap are arranged between the bearing gland and the end cover, the first annular cavity can accommodate the externally introduced gas therein, the gas is buffered and slowed down, and then the gas is supplied to the second annular gap in a permeable manner through the first annular gap, so as to effectively seal the bearing locking part between the bearing gland and the end cover, the structure relies on two axially adjacent parts to form the first annular cavity and the first annular gap in the entire circumferential direction, after the sealing gas enters through the gas inlet channel, it first fills the first annular cavity, and then permeates into the second annular gap from the first annular gap, the uniformity of the gas curtain is greatly enhanced; the impurities (including fluids and the like) entering the matching gap of the cover plate are blocked and sealed, preventing them from entering the internal position of the bearing and the like, and since the first annular cavity and the first annular gap are annular structures, the dispersion area of the gas curtain is increased, the uniformity of the circumferential gas curtain is increased, and the sealing effect of the electric spindle is enhanced, solving the problem of circumferential pressure unevenness of the front end gas seal gap of the spindle;

[0043] 2. The present application is also characterized in that a first tortuous gap is arranged between the matching gap of the cover plate and the second annular gap, the resistance of the fluid entering the first tortuous gap from the matching gap is effectively increased, so as to further prevent the dirty gas at the front end of the cover plate from entering the second annular gap through the matching gap, effectively enhancing the sealing performance of the electric spindle, and since the second annular gap receives the sealing gas sent from the first annular cavity and the first annular gap, and then reaches the first tortuous gap, the dirty gas at the matching gap can be further prevented from entering the second annular gap through the first tortuous gap, further improving the sealing performance of the electric spindle; the present application is also characterized in that a second annular cavity and a second tortuous gap are arranged between the sealing part and the bearing gland, the resistance to the fluid is further increased, the fluid is buffered and slowed down through the second annular cavity, so as to reduce the fluid reaching the bearing part, and the bearing part is sealed, further improving the sealing performance of the electric spindle;

[0044] 3. The present application is also characterized in that a dirt collecting groove, a dirt discharge hole and a dirt discharge channel are arranged in communication with the second annular gap at the end cover, so that the pollutants entering the second annular gap through the first tortuous gap can still be thrown out of the dirt discharge hole to the dirt collecting groove under the action of centrifugal force and discharged along the downwardly inclined dirt discharge channel, ensuring the purity of the gas in the electric spindle assembly, increasing the amount of sealing gas, further improving the sealing performance of the electric spindle, and solving the problem of dirt entering the front end of the spindle. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is the longitudinal section view of the sealing assembly of the vertical machining center electric spindle of the present application;

[0046] Figure 2 isFigure 1 A magnified view of part A;

[0047] Figure 3 This is the invention Figure 1 A three-dimensional structural diagram of the bearing locking component;

[0048] Figure 4 yes Figure 2 A magnified view of part B in the diagram;

[0049] Figure 5 yes Figure 2 A magnified view of part C in the image;

[0050] Figure 6 yes Figure 2 A magnified view of part D in the image.

[0051] The attached figures are labeled as follows:

[0052] 1. Mandrel; 2. Bearing; 3. Bearing locking element; 4. Bearing cap; 5. End cap; 6. First annular cavity; 7. First annular gap; 8. Second annular gap; 9. First air inlet channel; 10. Second air inlet channel; 11. Third air inlet channel; 12. Bearing housing; 13. Fourth air inlet channel; 14. Cover plate; 15. First bend gap; 16. Fitting clearance; 17. Protruding structure; 18. Groove structure; 19. First axial clearance; 2 0. First radial clearance; 21. Second axial clearance; 22. Second radial clearance; 23. Third axial clearance; 24. Seal; 25. First protrusion; 26. Second protrusion; 27. Second zigzag clearance; 28. Second annular cavity; 29. ​​First rib; 30. First recess; 31. Second rib; 32. Second recess; 33. Sewage collection trough; 34. Sewage discharge channel; 35. Knife handle; 36. Bearing sleeve; 37. Sewage discharge hole. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0055] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless specifically so stated. It is also to be understood that the dimensions shown in the drawings are not necessarily to scale, and that the various parts are shown only with the understanding that their dimensions, shapes, and other characteristics can be varied in accordance with the specific application. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as though one skilled in the art had knowledge thereof. In the examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation. Other examples of the example embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the several views, and that the use of the same number or letter in different figures indicates that the parts identified by those numbers or letters are considered to be the same parts, and thus, further discussion of the same parts is not necessary in the subsequent figures.

[0056] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "up", "down", "left", "right", "horizontal", "vertical", "top", "bottom", and the like are generally based on the orientation or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present application; the orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the parts themselves.

[0057] 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 element or feature to another element or feature 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 the device in the figures is turned over, elements described as "above" or "up" other elements or features would then be oriented "below" or "down" the other elements or features. 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.

[0058] In addition, it should be pointed out that the use of the words "first", "second" and the like to define parts is merely for the convenience of distinguishing the corresponding parts, and the words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0059] As shown in the drawings, Figures 1-6 The present application provides a main shaft end gas seal assembly, which comprises:

[0060] A mandrel 1, a bearing locking member 3, a bearing gland 4, an end cover 5 and a gas inlet passage, the bearing locking member 3 is arranged on the outer periphery of the mandrel 1 to rotate integrally with the mandrel 1, at least part of the structure of the bearing gland 4 and at least part of the structure of the end cover 5 are arranged on the outer periphery of the part of the structure of the bearing locking member 3 respectively, the end cover 5 and the bearing gland 4 have at least part of the structure in contact in the axial direction, and there is a second annular gap 8 between the outer periphery of the bearing locking member 3 and the inner periphery of the bearing gland 4.

[0061] A first annular cavity 6 and a first annular gap 7 are arranged between the axial end of the bearing gland 4 towards the end cover 5 and the axial end of the end cover 5 towards the bearing gland 4, the radial inner end of the first annular gap 7 is in communication with the second annular gap 8, the radial outer end of the first annular gap 7 is in communication with the first annular cavity 6, the flow cross-sectional area of the first annular cavity 6 is larger than that of the first annular gap 7, and the gas inlet passage can introduce gas into the first annular cavity 6.

[0062] The first annular cavity and the first annular gap arranged between the bearing gland and the end cover, the first annular cavity can receive the externally introduced gas therein, the gas is buffered and slowed down, and then the gas is supplied to the second annular gap in a permeable mode through the first annular gap, so that the bearing locking part and the bearing gland and the end cover are effectively sealed, the structure relies on two axially adjacent parts to form the first annular cavity and the first annular gap in the entire circumferential direction, after the sealing gas enters through the gas inlet channel, the first annular cavity is filled first, and then the second annular gap is permeated from the first annular gap, so that the uniformity of the gas curtain is greatly enhanced; the impurities (including fluid and the like) entering through the matching gap of the cover plate are blocked and sealed, so that the impurities are prevented from entering the internal position of the bearing and the like, and since the first annular cavity and the first annular gap are annular structures, the dispersion area of the gas curtain is increased, the uniformity of the circumferential gas curtain is increased, and the sealing effect on the motorized spindle is enhanced, so that the problem of circumferential gas pressure unevenness of the front end gas seal gap of the motorized spindle is solved.

[0063] The gas flow of the present application is not directly blown to the axial cylindrical gap (i.e. the second annular gap), but is blown to the first annular cavity formed by the adjacent stationary part in the axial direction, and then permeates into the cylindrical surface gap of the rotating part through the end surface gap formed by the stationary part, compared with the limited uniform hole permeation in the gas seal ring, the gas curtain of the air door is more uniform in the circumferential direction, and the sealing performance is greatly improved compared with the direct blowing structure in the prior art.

[0064] The present application solves the following technical problems:

[0065] 1. The problem of circumferential gas pressure unevenness of the front end gas seal gap of the motorized spindle is solved.

[0066] 2. The problem of pollution entering the front end of the motorized spindle is solved.

[0067] In some embodiments,

[0068] The second annular gap 8 also extends between the outer periphery of the bearing locking part 3 and the inner periphery of the end cover 5; the first annular cavity 6 is a cavity formed by recessing the axial end face of the bearing gland 4 facing the end cover 5 away from the end cover 5, the first annular cavity 6 is a circumferentially surrounding annular cavity around the mandrel 1, the first annular gap 7 is a circumferentially surrounding annular gap around the mandrel 1, the axial height of the first annular cavity 6 is higher than the axial height of the first annular gap 7, and the radial length of the first annular cavity 6 is greater than or equal to the radial length of the first annular gap 7.

[0069] This is a preferred structural form of the second annular gap, the first annular cavity, and the first annular gap of the present invention. Specifically, the second annular gap is formed between the inner circumference of the end cap and the inner circumference of the bearing cap and the outer circumference of the bearing locking member, allowing gas to pass through and seal the rotating part (bearing locking member) and the fixed part (end cap and bearing cap). The first annular cavity is preferably formed by creating a groove in the bearing cap. Both the first annular cavity and the first annular gap are annular structures, which can effectively increase the annular sealing effect between the bearing locking member and the end cap (and / or bearing cap) in the second annular gap, improving the uniformity of the seal. The first annular cavity, with its axial height and radial length greater than the corresponding dimensions of the first annular gap, allows gas to enter and buffer and decelerate, thereby forming a slow, annular permeation into the second annular gap through the first annular gap, improving the uniformity of the seal and enhancing the sealing performance.

[0070] The main improvement of this invention lies in using a first annular chamber formed by adjacent stationary parts to store air, and using the annular gap formed therein to permeate sealing air into the cylindrical gap of the shaft (i.e., the second annular gap) to form a circumferential air curtain. Compared with the sealing air entering the cylindrical gap of the rotating part (shaft or locking nut on the shaft) (i.e., the second annular gap) directly from a single or limited number of radial holes, the air curtain pressure is more uniform in the circumferential direction, and the sealing performance is better.

[0071] In some implementations...

[0072] It also includes a cover plate 14, which is disposed at one axial end of the end cover 5 away from the bearing cap 4 and is fixedly connected to the end cover 5. The radially inner portion of the cover plate 14 extends to be axially opposite to the bearing locking member 3, and a first tortuous gap 15 is provided between the radially inner portion of the cover plate 14 and the bearing locking member 3. The radially inner end of the cover plate 14 has a fitting gap 16 with the spindle 1. The fitting gap 16 communicates with the first tortuous gap 15. The first tortuous gap 15 can change the flow direction of the fluid flowing into the first tortuous gap 15 through the fitting gap 16 more than once.

[0073] The application can fix the axial end of the end cover through the structure of the cover plate, and since the cover plate is a fixed part, a matching gap needs to be arranged between the cover plate and the mandrel of the inner periphery to meet the rotation of the mandrel, but the gap may suck in the contaminants (such as dirty gas) outside the axial direction of the cover plate, which may affect the second annular gap, and even enter the bearing position, resulting in adverse conditions. The application sets a first zigzag gap between the radial inner side part segment of the cover plate and the bearing locking part, effectively increasing the resistance of the fluid entering the first zigzag gap from the matching gap, thereby further preventing the dirty gas at the front end of the cover plate from entering the second annular gap through the matching gap, and effectively enhancing the sealing performance of the internal part of the electric spindle.

[0074] Figure 1 A gas seal structure applied to an electric spindle of a vertical machining center is given. The front end stationary part of the spindle includes a cover plate 14, a front end cover (end cover 5), a front bearing gland (bearing gland 4), a front bearing seat (bearing seat 12) and a bearing sleeve 36; the front end rotating part of the spindle includes a mandrel 1, a front bearing (bearing 2), a front spacer ring (seal 24), a front bearing locking nut (bearing locking part 3) and a tool shank 35. The bearing seat 12 and the bearing gland 4 of the spindle are respectively provided with gas seal inlet flow channels, wherein the first inlet flow channel 9 is opened on the bearing seat, and the second inlet flow channel 10 and the third inlet flow channel 11 are opened on the bearing gland 4 and are connected in communication.

[0075] Figure 2 A partial enlarged view of the sealing structure is given, in which the two axially adjacent parts, the front bearing gland and the front end cover, form a first annular cavity 6 and a first annular gap 7 in the entire circumferential direction. After the sealing gas enters the inlet flow channel, it first fills the first annular cavity 6, and then seeps into the second annular gap 8 from the first annular gap 7 around the whole circumference. The sealing gas flows out from the second annular gap upward and downward, respectively. The upward gas flow flows into the second annular cavity 28, and then flows out from the second zigzag gap 27 formed by the front spacer ring (seal 24) and the bearing gland 4; the downward gas flow flows out from the first zigzag gap 15 formed by the cover plate 14 and the bearing locking part 3. Figure 5 The arrow direction in the figure is the direction of the external chips or dust, contaminants entering the sealing gap of the spindle, which is opposite to the direction of the sealing gas blowing out.

[0076] In some embodiments,

[0077] The end of the first tortuous gap 15 away from the matching gap 16 communicates with the second annular gap 8, and the gas entering the second annular gap 8 from the first annular cavity 6 can enter the first tortuous gap 15 to prevent the fluid at the matching gap 16 from flowing into the second annular gap 8. Since the second annular gap of the present application communicates with the radially outer end of the first tortuous gap, the second annular gap can receive the sealing gas from the first annular cavity and the first annular gap, and then into the first tortuous gap, which can further prevent the dirty gas at the matching gap from entering the second annular gap through the first tortuous gap, and further improve the sealing performance of the internal part of the electric spindle.

[0078] In some embodiments,

[0079] The radially inner portion of the cover plate 14 is provided with at least one protruding structure 17 on the axial end surface thereof facing the bearing locking member 3, the axial end surface of the bearing locking member 3 is provided with at least one recess structure 18 on the axial end surface thereof facing away from the cover plate 14, the protruding structure 17 can be inserted into the recess structure 18, the top of the protruding structure 17 and the bottom of the recess structure 18 have a second axial gap 21, the radially inner end of the protruding structure 17 and the radially inner end of the recess structure 18 have a first radial gap 20, the radially outer end of the protruding structure 17 and the radially outer end of the recess structure 18 have a second radial gap 22, the recess structure 18 is located between the radially inner end and the radially outer end of the bearing locking member 3, and the portion between the radially inner end of the bearing locking member 3 and the recess structure 18 has a first axial gap 19 in the axial direction with the cover plate 14, and the portion between the radially outer end of the bearing locking member 3 and the recess structure 18 has a third axial gap 23 in the axial direction with the cover plate 14, and the first tortuous gap 15 includes the first axial gap 19, the first radial gap 20, the second axial gap 21, the second radial gap 22 and the third axial gap 23.

[0080] This is a further preferred structure of the first tortuous gap of the present application, that is, through the structure of the matching protruding structure and recess structure, the first axial gap, the first radial gap, the second axial gap, the second radial gap and the third axial gap can be sequentially communicated between the matching gap and the second annular gap, which further effectively increases the air flow resistance between the matching gap and the second annular gap, effectively ensures the effective sealing effect at the second annular gap, and further improves the sealing performance of the internal part of the electric spindle.

[0081] The first tortuous gap 15 of this invention forms a three-level labyrinth cavity by combining radial and axial gaps. When contaminants enter at the gap inlet, the contaminants must undergo six 90° deflections at this tortuous gap. Figure 5 Only by following the arrow markings can one enter the second annular gap 8.

[0082] In some implementations...

[0083] The end cover 5 has a sludge collection groove 33 at its radially inner end, and the bearing locking member 3 has a sludge discharge hole 37 at its radially outer end. The sludge collection groove 33 and the sludge discharge hole 37 are connected through the second annular gap 8. The end cover 5 also has a sludge discharge channel 34 inside, with one end connected to the sludge collection groove 33 and the other end connected to the outside of the end cover 5. This invention, by providing a sludge collection groove, a sludge discharge hole, and a sludge discharge channel at the end cover that are connected to the second annular gap, allows contaminants that have entered the second annular gap after overcoming the first tortuous gap to still be thrown out from the sludge discharge hole into the sludge collection groove under centrifugal force and discharged along the downwardly inclined sludge discharge channel. This ensures the purity of the gas inside the electric spindle assembly, increases the amount of sealing gas introduced, further improves the sealing performance inside the electric spindle, and solves the problem of sludge discharge from the front end of the spindle.

[0084] This invention Figure 3 In the bearing locking component 3, three radial drain holes 37 are provided. When contaminants enter, they are thrown out through the drain holes 37 under centrifugal force into the annular collection groove 33 on the front end cover, and then discharged through the drain channel 34. The drain channel 34 is opened at a certain angle to facilitate the outflow of contaminants in vertical installation. For contaminants entering the second annular gap 8, the continuous downward sealing airflow in the second annular gap 8 can seal the contaminants in the collection groove and discharge them.

[0085] In some implementations...

[0086] The sludge collection groove 33 is a recessed groove structure formed on the radially inner end face of the end cover 5 in a direction away from the bearing locking member 3. The sludge discharge hole 37 is a recessed groove structure formed on the radially outer end face of the bearing locking member 3 in a direction away from the end cover 5. The sludge collection groove 33 is an annular structure. The sludge discharge hole 37 is a plurality of holes spaced apart circumferentially. The sludge discharge hole 37 is connected to the first tortuous gap 15 (preferably connected to the groove structure 18). The radially inner end of the sludge discharge channel 34 is connected to the sludge collection groove 33, and the radially outer end extends to the radially outer periphery of the end cover 5 to discharge pollutants (including gas, liquid and solid impurities, etc.).

[0087] This is the preferred formation of the sump and the drain hole of the application, that is, the sump is a groove formed at the radial inner end of the end cover, the drain hole is formed at the radial outer end of the bearing locking member, so that the sump communicates with the drain hole through the second annular gap, the drain hole communicates with the internal recess structure to introduce the dirty gas, and the dirty gas is discharged to the outside of the end cover through the sump and the drain passage, and the dirty gas is thrown out by the rotation centrifugal force of the bearing locking member.

[0088] In some embodiments,

[0089] The sump 33 is arranged at a position close to the first curved gap 15 relative to the first annular gap 7 in the axial direction; the drain passage 34 is a straight passage, the central axis of which is not perpendicular to the central axis of the mandrel 1, and when the central axis of the mandrel 1 extends in the vertical direction, the height of the radial outer end of the drain passage 34 is lower than that of the radial inner end.

[0090] In some embodiments,

[0091] The cover plate 14 and the end cover 5 are fixed by threaded fasteners; one axial end of the mandrel 1 is connected with a tool holder 35, and the tool holder 35 and the cover plate 14 are arranged at the axial end of the mandrel 1; the outer periphery of the bearing seat 12 is further provided with a bearing sleeve 36. The bearing locking member is preferably a bearing locking nut, and the sealing member is preferably a front spacer ring.

[0092] The cover plate of the application is preferably threadedly fastened with the end cover to keep them fixed as a whole, the tool holder structure at one end of the mandrel can process the parts to be machined on the machine tool, and the bearing sleeve can protect and support the bearing seat.

[0093] In some embodiments,

[0094] Further comprising a bearing 2 arranged at the outer periphery of the mandrel 1 to support the mandrel 1, and the bearing locking member 3 can act on the axial end of the inner ring of the bearing 2. The application can support the mandrel thereon and rotate through the arrangement of the bearing, and the bearing locking member acts to pre-tighten the axial end of the inner ring of the bearing, ensuring the stability of the bearing during the rotation of the mandrel.

[0095] In some embodiments,

[0096] The air inlet channel comprises a second air inlet channel 10 and a third air inlet channel 11 arranged inside the bearing gland 4, one end of the third air inlet channel 11 is communicated with the first annular cavity 6, the third air inlet channel 11 is communicated between the second air inlet channel 10 and the first annular cavity 6, the extending direction of the second air inlet channel 10 is not parallel to the extending direction of the third air inlet channel 11, and the included angle between them is between (0, 90].

[0097] The bearing seat 12 is arranged at the outer periphery of the bearing 2 to support the bearing 2, and the air inlet channel further comprises a first air inlet channel 9 arranged inside the bearing seat 12, one end of the bearing seat 12 is connected with the bearing gland 4, one end of the first air inlet channel 9 can be communicated with the second air inlet channel 10, and the other end can introduce gas.

[0098] This is the preferred structure of the air inlet channel of the application, preferably two second and third air inlet channels are arranged inside the bearing gland and communicated with each other, and the first air inlet channel is arranged on the bearing seat, so that the sealing gas introduced from the outside through the first air inlet channel enters the second and third air inlet channels in turn and then enters the first annular cavity, thereby providing the sealing performance between the bearing locking member and the bearing gland and the end cover.

[0099] In some embodiments,

[0100] The air inlet channel further comprises a fourth air inlet channel 13 arranged on the bearing gland 4, the fourth air inlet channel 13 is communicated between the first air inlet channel 9 and the second air inlet channel 10, the first air inlet channel 9 and the fourth air inlet channel 13 are both straight channels, and the center axes of the two are coincident and arranged parallel to the axis of the mandrel 1, the second air inlet channel 10 is also a straight channel, and the center axis thereof is perpendicular to the center axis of the fourth air inlet channel 13, and the third air inlet channel 11 is also a straight channel, and the center axis thereof is perpendicular to the center axis of the second air inlet channel 10.

[0101] The application further preferably arranges a fourth air inlet channel on the bearing gland, which can communicate the first air inlet channel with the second air inlet channel, and the center axes of the first, fourth and third air inlet channels are all parallel to the axis of the mandrel, while the center axis of the second air inlet channel is perpendicular to the center axis of the mandrel, so as to ensure that the sealing gas is effectively transmitted to the first annular cavity.

[0102] In some embodiments,

[0103] The radially inner side of the bearing cover 4 away from the axial end of the end cover 5 is in axial connection with the outer ring of the bearing 2; the radially outer end of the second air inlet channel 10 penetrates to the radially outer circumferential surface of the bearing cover 4, and a plug is arranged at the radially outer end of the second air inlet channel 10.

[0104] The bearing cover of the application is preferably in axial connection with the bearing outer ring, thereby effectively supporting the bearing outer ring; the second air inlet channel penetrates to the radially outer circumferential surface of the bearing cover for the convenience of processing the second air inlet channel; and the plug arranged at the radially outer end ensures that the second air inlet channel can only suck in air from the first air inlet channel, but not from the plug.

[0105] In some embodiments,

[0106] Further comprising a seal 24 arranged on the outer circumferential surface of the mandrel 1 to rotate integrally with the mandrel 1 and to act on the axial end of the inner ring of the bearing 2, the seal 24 is arranged between the axial end of the inner ring of the bearing 2 and the bearing locking member 3, and the bearing locking member 3 applies a fastening force to the inner ring of the bearing 2 through the seal 24.

[0107] The application further transmits the pre-tightening force of the bearing locking member to the axial end of the inner ring of the bearing through the arrangement of the seal, thereby providing pre-tightening force to the inner ring of the bearing; and the seal is preferably a front spacer, which can deform to further enhance the self-adjusting performance of the pre-tightening force to the inner ring of the bearing.

[0108] In some embodiments,

[0109] The part of the structure of the bearing cover 4 is opposite to the seal 24 in the radial direction, the first protruding part 25 is arranged on the part of the structure of the bearing cover 4 opposite to the seal 24 in the radial direction and protrudes towards the seal 24, the second protruding part 26 is arranged on the seal 24 and protrudes towards the bearing cover 4, the second tortuous gap 27 is formed between the first protruding part 25 and the second protruding part 26, the second annular cavity 28 is formed between the first protruding part 25 and the bearing locking member 3, the radially outer end of the second annular cavity 28 is in communication with the second annular gap 8, and the radially inner end of the second annular cavity 28 is in communication with the second tortuous gap 27.

[0110] The first protruding part and the second protruding part arranged between the sealing element and the bearing gland effectively form the second annular cavity and the second tortuous gap, can increase the resistance of the second annular gap flowing towards the bearing direction, buffer and slow down the fluid through the second annular cavity, thereby reducing the fluid reaching the bearing, plays a sealing role on the bearing part and the like, and further improves the sealing performance of the internal part of the electric spindle.

[0111] The second tortuous gap 27 of the electric spindle is also formed by the radial gap and the axial gap to form a labyrinth cavity, prevents the oil gas after lubricating the bearing from entering the second annular cavity, and the upward continuous sealing gas flow in the second annular gap blocks the oil gas into the oil return channel.

[0112] The gap amount of the first annular gap is preferably 0.2 mm (the gap between the bearing gland and the end cover); the gap amount at the second annular gap is preferably 0.25 mm (the gap between the bearing locking element and the bearing gland); and the minimum gap amount at the first tortuous gap and the second tortuous gap is preferably 0.25 mm, and the maximum gap amount is preferably 1 mm.

[0113] In some embodiments,

[0114] The first protruding part 25 and the second protruding part 26 are arranged opposite in the axial direction, at least two first protruding ribs 29 are arranged on the first protruding part 25 in the direction of the second protruding part 26, a first recess 30 is formed between two adjacent first protruding ribs 29, at least two second protruding ribs 31 are arranged on the second protruding part 26 in the direction of the first protruding part 25, a second recess 32 is formed between two adjacent second protruding ribs 31, the first protruding rib 29 and the second recess 32 are inserted and matched, and a first gas gap is formed, the second protruding rib 31 and the first recess 30 are inserted and matched, and a second gas gap is formed, and the second tortuous gap 27 includes the first gas gap and the second gas gap.

[0115] This is a further preferred structure of the second tortuous gap of the electric spindle, which can form a multi-segment bending channel, provide a labyrinth seal, further increase the resistance of the fluid flowing to the bearing, and further enhance the sealing performance of the bearing.

[0116] The electric spindle also provides a spindle shaft end gas seal assembly.

[0117] The improvement of the electric spindle is that:

[0118] 1. A spindle front end gas seal structure is provided, which relies on two axially adjacent parts to form a first annular cavity and a first annular gap in the entire circumferential direction. After the sealing gas enters from the gas inlet channel, it first fills the first annular cavity, and then penetrates into the second annular gap from the first annular gap. The uniformity of the gas curtain is greatly enhanced.

[0119] 2. The entrance of the sealing gap (i.e. the second annular gap) is provided with 6-stage 90° gap deflection, which significantly increases the entry resistance of the contaminants, and 3 blow-off holes are opened on the front bearing locking nut (bearing locking member 3), so that even if the contaminants overcome the multi-stage deflection to enter the sealing gap, they can still be thrown out of the blow-off holes to the collection tank under the action of centrifugal force and discharged along the downwardly inclined blow-off channel.

[0120] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application. The above description is only the preferred embodiment of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and variations can be made, which should be considered as the protection scope of the present application.

Claims

1. A spindle end gas seal assembly, characterized in that: include: The assembly includes a spindle (1), a bearing locking member (3), a bearing cap (4), an end cap (5), and an air intake channel. The bearing locking member (3) is disposed on the outer periphery of the spindle (1) to rotate integrally with the spindle (1). At least a portion of the structure of the bearing cap (4) and at least a portion of the structure of the end cap (5) are respectively disposed on the outer periphery of a portion of the structure of the bearing locking member (3). The end cap (5) and the bearing cap (4) are connected in at least a portion of their structures in the axial direction. A second annular gap (8) exists between the outer periphery of the bearing locking member (3) and the inner periphery of the bearing cap (4). A first annular cavity (6) and a first annular gap (7) are provided between the axial end of the bearing cap (4) facing the end cap (5) and the axial end of the end cap (5) facing the bearing cap (4). The radial inner end of the first annular gap (7) is connected to the second annular gap (8), and the radial outer end of the first annular gap (7) is connected to the first annular cavity (6). The flow cross-sectional area of ​​the first annular cavity (6) is larger than the flow cross-sectional area of ​​the first annular gap (7). The air intake channel can introduce gas into the first annular cavity (6). The end cap (5) has a sludge collection groove (33) at its radial inner end and a sludge discharge hole (37) at its radial outer end. The sludge collection groove (33) and the sludge discharge hole (37) are connected through the second annular gap (8). The end cap (5) also has a sludge discharge channel (34) inside. One end of the sludge discharge channel (34) is connected to the sludge collection groove (33) and the other end is connected to the outside of the end cap (5).

2. The spindle end gas seal assembly according to claim 1, characterized in that: The second annular gap (8) extends to the outer periphery of the bearing locking member (3) and the inner periphery of the end cover (5); the first annular cavity (6) is a cavity formed by the axial end face of the bearing cover (4) facing the end cover (5) in a direction away from the end cover (5); the first annular cavity (6) is an annular cavity that surrounds the spindle (1); the first annular gap (7) is an annular gap that surrounds the spindle (1); the axial height of the first annular cavity (6) is higher than the axial height of the first annular gap (7); and the radial length of the first annular cavity (6) is greater than or equal to the radial length of the first annular gap (7).

3. The spindle end gas seal assembly according to claim 1, characterized in that: It also includes a cover plate (14), which is disposed on the axial end of the end cover (5) away from the bearing cap (4) and is fixedly connected to the end cover (5). The radially inner portion of the cover plate (14) extends to be axially opposite to the bearing locking member (3), and a first tortuous gap (15) is provided between the radially inner portion of the cover plate (14) and the bearing locking member (3). The radially inner end of the cover plate (14) has a fitting gap (16) with the spindle (1). The fitting gap (16) communicates with the first tortuous gap (15). The first tortuous gap (15) can change the flow direction of the fluid flowing into the first tortuous gap (15) through the fitting gap (16) more than once.

4. The spindle end gas seal assembly according to claim 3, characterized in that: One end of the first tortuous gap (15) away from the mating gap (16) is connected to the second annular gap (8). Gas that enters the second annular gap (8) through the first annular cavity (6) can enter the first tortuous gap (15) to prevent fluid at the mating gap (16) from flowing into the second annular gap (8).

5. The spindle end gas seal assembly according to claim 3, characterized in that: The inner radial portion of the cover plate (14) has at least one protruding structure (17) protruding towards the bearing locking member (3) on its axial end face. The bearing locking member (3) has at least one recessed groove structure (18) recessed away from the cover plate (14) on its axial end face. The protruding structure (17) can be inserted into the groove structure (18). There is a second axial gap (21) between the top of the protruding structure (17) and the bottom of the groove structure (18). There is a first radial gap (20) between the inner radial end of the protruding structure (17) and the inner radial end of the groove structure (18). The outer radial end of the protruding structure (17) and the groove structure (18) have a first radial gap (20). The groove structure (18) has a second radial gap (22) between its radial outer ends. The groove structure (18) is located between the radial inner end and the radial outer end of the bearing locking member (3). The portion of the bearing locking member (3) between its radial inner end and the groove structure (18) has a first axial gap (19) between it and the cover plate (14) along the axial direction. The portion of the bearing locking member (3) between its radial outer end and the groove structure (18) has a third axial gap (23) between it and the cover plate (14) along the axial direction. The first tortuous gap (15) includes the first axial gap (19), the first radial gap (20), the second axial gap (21), the second radial gap (22), and the third axial gap (23).

6. The spindle end gas seal assembly according to claim 3, characterized in that: The sludge collection groove (33) is a recessed groove structure formed on the radial inner end face of the end cover (5) in a direction away from the bearing locking member (3). The sludge discharge hole (37) is a recessed groove structure formed on the radial outer end face of the bearing locking member (3) in a direction away from the end cover (5). The sludge collection groove (33) is an annular structure. The sludge discharge hole (37) is a plurality of holes spaced apart along the circumference. The sludge discharge hole (37) is connected to the first tortuous gap (15). The radial inner end of the sludge discharge channel (34) is connected to the sludge collection groove (33), and the radial outer end extends to the radial outer periphery of the end cover (5).

7. The spindle end gas seal assembly according to claim 6, characterized in that: The sludge collection trough (33) is positioned in the axial direction relative to the first annular gap (7) and close to the first tortuous gap (15); the sewage discharge channel (34) is a straight channel, and its central axis is not perpendicular to the central axis of the mandrel (1). When the central axis of the mandrel (1) extends in the vertical direction, the height of the radial outer end of the sewage discharge channel (34) is lower than the height of its radial inner end.

8. The spindle end gas seal assembly according to claim 3, characterized in that: The cover plate (14) and the end cap (5) are fixed by threaded fasteners; a tool holder (35) is connected to one axial end of the spindle (1), and the tool holder (35) and the cover plate (14) are both located at one axial end of the spindle (1).

9. The spindle end gas seal assembly according to any one of claims 1-8, characterized in that: It also includes a bearing (2), which is disposed on the outer periphery of the mandrel (1) to support the mandrel (1), and the bearing locking member (3) can act on one axial end of the inner ring of the bearing (2).

10. The spindle end gas seal assembly according to claim 9, characterized in that: The air intake channel includes a second air intake channel (10) and a third air intake channel (11) disposed inside the bearing cover (4). One end of the third air intake channel (11) is connected to the first annular cavity (6). The third air intake channel (11) is connected between the second air intake channel (10) and the first annular cavity (6). The extension direction of the second air intake channel (10) is not parallel to the extension direction of the third air intake channel (11), and they form an angle between (0, 90). It also includes a bearing housing (12), which is disposed on the outer periphery of the bearing (2) to support the bearing (2). The air intake channel also includes a first air intake channel (9) disposed inside the bearing housing (12). One axial end of the bearing housing (12) is connected to the bearing cap (4). One end of the first air intake channel (9) can communicate with the second air intake channel (10), and the other end can introduce gas.

11. The spindle end gas seal assembly according to claim 10, characterized in that: The air intake channel also includes a fourth air intake channel (13) disposed on the bearing cover (4). The fourth air intake channel (13) is connected between the first air intake channel (9) and the second air intake channel (10). The first air intake channel (9) and the fourth air intake channel (13) are both direct current channels, and their central axes overlap and are arranged parallel to the axis of the spindle (1). The second air intake channel (10) is also a direct current channel and its central axis is perpendicular to the central axis of the fourth air intake channel (13). The third air intake channel (11) is also a direct current channel and its central axis is perpendicular to the central axis of the second air intake channel (10).

12. The spindle end gas seal assembly according to claim 10, characterized in that: The radial inner side of the bearing cap (4) at one end away from the end cap (5) is axially connected to the outer ring of the bearing (2); the radial outer end of the second air intake channel (10) extends to the radial outer circumferential surface of the bearing cap (4), and a plug is provided at the radial outer end of the second air intake channel (10); a bearing sleeve (36) is also provided on the outer circumference of the bearing seat (12).

13. The spindle end gas seal assembly according to claim 9, characterized in that: It also includes a seal (24), which is disposed on the outer periphery of the mandrel (1) to rotate integrally with the mandrel (1) and can act on one axial end of the inner ring of the bearing (2). The seal (24) is disposed between one axial end of the inner ring of the bearing (2) and the bearing locking member (3). The bearing locking member (3) applies a fastening force to the inner ring of the bearing (2) through the seal (24).

14. The spindle end gas seal assembly according to claim 13, characterized in that: A portion of the bearing cap (4) is radially opposite to the seal (24). A first protrusion (25) is provided on the radially opposite portion of the bearing cap (4) towards the seal (24). A second protrusion (26) is provided on the seal (24) towards the bearing cap (4). A second tortuous gap (27) is formed between the first protrusion (25) and the second protrusion (26). A second annular cavity (28) is formed between the first protrusion (25) and the bearing locking member (3). The radially outer end of the second annular cavity (28) communicates with the second annular gap (8), and the radially inner end of the second annular cavity (28) communicates with the second tortuous gap (27).

15. The spindle end gas seal assembly according to claim 14, characterized in that: The first protrusion (25) and the second protrusion (26) are arranged opposite each other along the axial direction, and at least two first ribs (29) are provided on the first protrusion (25) in the direction of the second protrusion (26). A first recess (30) is formed between two adjacent first ribs (29). At least two second ribs (31) are provided on the second protrusion (26) in the direction of the first protrusion (25). A second recess (32) is formed between two adjacent second ribs (31). The first rib (29) and the second recess (32) are inserted and cooperate to form a first gas gap. The second rib (31) and the first recess (30) are inserted and cooperate to form a second gas gap. The second tortuous gap (27) includes the first gas gap and the second gas gap.

16. An electric spindle, characterized in that: Includes the spindle end gas seal assembly according to any one of claims 1-15.

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