A sealing device, an electric spindle, and a CNC machine tool

Abstract

This invention relates to the field of electric motors, specifically to a sealing device, an electric spindle, and a CNC machine tool. The sealing device includes a flange with a flange hole, the flange being fitted onto a rotating shaft through the flange hole, and an air inlet on the flange. The flange hole includes a first inner inclined surface whose diameter gradually increases from the inside to the outside, and the exhaust port of the air inlet is located on the first inner inclined surface. A first sealing ring is fitted onto the rotating shaft and located within the flange hole. The outer circumferential surface of the first sealing ring includes a first outer inclined surface whose diameter gradually increases from the inside to the outside. The first outer inclined surface and the first inner inclined surface are opposite to each other, and a first gap is formed between them, so as to improve the sealing effect on the bearing supporting the rotating shaft when the electric spindle is working.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more specifically to a sealing device, an electric spindle, and a CNC machine tool. Background Technology

[0002] Electric spindles are a new technology in the field of CNC machine tools that integrates the machine tool spindle and spindle motor. Compared to traditional mechanical spindles, electric spindles use an integrated spindle and rotor, replacing the traditional belt and gear transmission methods of mechanical spindles. This greatly improves the spindle's performance at high speeds and makes it more integrated and precise. In recent years, the machining field has developed rapidly, and electric spindle technology, as its core technology, has also made great progress.

[0003] Electric spindles are precision components. Under high-speed operation, even the slightest dust entering the spindle bearings can cause spindle vibration or even seizure. Therefore, the sealing performance of the spindle largely determines its accuracy and lifespan, and proper sealing is essential in the design of electric spindle products. Since the motor of an electric spindle is built-in, moisture and dust inside the motor can deteriorate the insulation of the motor windings, even causing failure and ultimately burning out the motor. Therefore, electric spindles must be dustproof and moisture-proof. The most critical aspect is preventing cutting fluid from entering the spindle bearings during high-speed cutting. In spindle maintenance problems, bearing failure accounts for 60%–70%. Besides issues with the bearing's lifespan and precision, approximately 50% of these failures are caused by water ingress into the bearings. Therefore, the sealing structure design of electric spindles is of paramount importance.

[0004] With the development of machine tool technology and high-speed cutting technology, and the demands of practical applications, increasingly higher requirements are being placed on the performance of machine tool electric spindles. Existing electric spindle sealing structures generally have poor sealing effects. To overcome these shortcomings...

[0005] In the prior art, the locking nut is rotatably mounted on the front cover, and an elastic sealing component is set between the front cover and the locking nut to prevent dust, coolant and other impurities from entering the spindle cavity. However, it lacks axial sealing and the overall sealing performance is poor.

[0006] Another type of sealing structure prevents grease leakage. It has an outer cover oil seal between the outer bearing cover and the motor shaft, and an inner cover oil seal between the inner bearing cover and the motor shaft. The bearing is sealed on both sides by the front and rear oil seals. This sealing method is not clean, is inconvenient to assemble, and has a mediocre sealing effect.

[0007] Another type of airtight structure prevents external liquids and dust from entering by filling the sealing part with high-pressure gas and continuously expelling it through airflow. However, this method does not consider the impact of the rotation of the shaft on the airtightness, so its effectiveness is generally limited. Summary of the Invention

[0008] This invention proposes a sealing device, an electric spindle, and a CNC machine tool, which improves the sealing effect on the bearings supporting the rotation of the spindle when the electric spindle is working.

[0009] In a first aspect, the present invention provides a sealing device for sealing an electric spindle, the electric spindle including a rotating shaft, comprising:

[0010] A flange having a flange hole, the flange being fitted onto the rotating shaft through the flange hole, the flange having an inflation hole, the flange hole including a first inner inclined surface whose diameter gradually increases from the inside to the outside, the vent of the inflation hole being located on the first inner inclined surface;

[0011] The first sealing ring is fitted on the rotating shaft and located in the flange hole. The outer circumferential surface of the first sealing ring includes a first outer inclined surface whose diameter gradually increases from the inside to the outside. The first outer inclined surface and the first inner inclined surface are opposite to each other and a first gap is formed between them.

[0012] Preferably, the flange hole includes a second inner inclined surface whose diameter gradually increases from the inside to the outside, and the second inner inclined surface is located outside the first inner inclined surface; the small end diameter of the second inner inclined surface is d1, and the large end diameter of the first inner inclined surface is d2, then d1≥d2;

[0013] The outer peripheral surface of the first sealing ring includes a second outer inclined surface whose diameter gradually increases from the inside to the outside. The second outer inclined surface is located outside the first outer inclined surface and is opposite to the second inner inclined surface. A second gap is formed between the second outer inclined surface and the second inner inclined surface, and the second gap communicates with the first gap.

[0014] Preferably, the flange is provided with a reserved hole, and the inlet of the reserved hole is located on the second inner inclined surface.

[0015] Preferably, the flange hole includes an inner cylindrical surface, which is disposed between the first inner inclined surface and the second inner inclined surface;

[0016] The outer peripheral surface of the first sealing ring includes an outer cylindrical surface, which is disposed between the first outer inclined surface and the second outer inclined surface and forms a first annular gap with the inner cylindrical surface. The first annular gap communicates with the first gap and the second gap.

[0017] Preferably, a plug is provided in the reserved hole.

[0018] Preferably, the inner end of the flange is provided with a first sealing part, and the rotating shaft is also provided with a second sealing ring, the second sealing ring being located inside the first sealing ring; the second sealing ring is provided with a second sealing part, and a labyrinth seal is formed between the second sealing part and the first sealing part.

[0019] Preferably, a gap is formed between the second sealing ring and the first sealing ring, and an elastic sealing ring is provided in the gap. The elastic sealing ring is fitted on the rotating shaft and elastically contacts the first sealing ring and the second sealing ring.

[0020] Preferably, the sealing device further includes an end cap, which is fitted onto the rotating shaft through a through hole and fixed to the outer end face of the flange.

[0021] Preferably, the flange includes a flange body and a gas-tight ring, and the flange body is provided with an annular relief groove;

[0022] The inner wall of the annular relief groove is provided with a first annular groove; the air inlet is connected to the outside of the flange body and the first annular groove; the gas sealing ring is provided with a plurality of air blowing holes; the gas sealing ring is sealed in the annular relief groove; the air blowing holes are connected to the first annular groove and the inner hole of the gas sealing ring.

[0023] And / or,

[0024] The inner wall of the annular clearance groove is provided with a second annular groove; the reserved hole connects the outside of the flange body and the second annular groove; the gas sealing ring is provided with multiple drain holes; the gas sealing ring is sealed in the annular clearance groove; the drain holes connect the second annular groove and the inner hole of the gas sealing ring.

[0025] Preferably, the first inner inclined surface and the first outer inclined surface are parallel to each other and make an angle α with the axis of rotation, then 30°≤α≤60°.

[0026] Secondly, the present invention also provides an electric spindle, including the rotating shaft and the sealing device.

[0027] Thirdly, the present invention also provides a CNC machine tool, including the aforementioned electric spindle.

[0028] This invention uses an air inlet to inflate the first gap, preventing external dust and liquid from entering the inner side of the flange, i.e., the side where the bearing supporting the shaft is located. Simultaneously, when the shaft rotates, the first outer inclined surface generates centrifugal motion on the dust and liquid entering the first gap. Due to the design of the inclination direction of the first outer inclined surface, the dust and liquid can move towards the direction of discharge from the first gap under the action of centrifugal force, thereby improving the sealing performance between the flange and the shaft, i.e., the sealing performance of the electric spindle. This prevents external impurities from entering the inner side of the flange and affecting the rotation of the bearing supporting the shaft. In other words, this invention improves the sealing performance between the flange and the shaft through the combined effect of continuously introducing high-pressure gas into the first gap and the centrifugal force of the first sealing ring. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the sealing device being mounted on the rotating shaft according to an embodiment of the present invention;

[0030] Figure 2 This is an embodiment of the present invention. Figure 1 Enlarged view of point A in the middle;

[0031] Figure 3 This is a schematic diagram of the axial direction of the front sealing ring in an embodiment of the present invention;

[0032] Figure 4 This is a radial schematic diagram of the front sealing ring in an embodiment of the present invention;

[0033] Figure 5 This is a radial sectional view of the front sealing ring in an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the flange axis according to an embodiment of the present invention;

[0035] Figure 7 This is a radial sectional view of the flange according to an embodiment of the present invention;

[0036] Figure 8 This is an embodiment of the present invention. Figure 7 Enlarged view at point B in the middle;

[0037] Figure 9 This is a radial sectional view of the flange body according to an embodiment of the present invention;

[0038] Figure 10 This is an embodiment of the present invention. Figure 9 Enlarged view at point C;

[0039] Figure 11 This is a radial sectional view of the gas-tight ring according to an embodiment of the present invention;

[0040] Figure 12 This is an axial schematic diagram of the gas sealing ring according to an embodiment of the present invention;

[0041] Figure 13 This is a perspective view of the elastic sealing ring according to an embodiment of the present invention;

[0042] Figure 14 This is a radial cross-sectional view of the elastic sealing ring according to an embodiment of the present invention.

[0043] The reference numerals in the attached figures are as follows:

[0044] 1. Rotating shaft; 2. Flange; 201. Flange body; 202. Gas sealing ring; 203. First sealing part; 2011. First annular groove; 2012. Second annular groove; 2021. Air blowing hole; 2022. Drain hole; 200. Flange hole; 300. Bearing; 301. Air filling hole; 302. Reserved hole; 303. Check valve;

[0045] 400, Spacing; 401, First sealing ring; 402, Second sealing ring; 403, Second sealing part; 404, Elastic sealing ring; 500, End cap; 501, First inner inclined surface; 502, Second inner inclined surface; 503, Relief groove; 504, Bolt; 505, Bearing seat; 601, First outer inclined surface; 602, Second outer inclined surface; 701, First gap; 702, Second gap; 801, Inner cylindrical surface; 802, Outer cylindrical surface; 901, First annular gap; 902, Second annular gap; 903, Third annular gap. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. 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.

[0047] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0048] It should be understood that the term "and / or" used in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship; "first" and "second" are used only to distinguish different technical features, not to indicate a chronological order; and "upper," "lower," "before," and "after" are used only to more conveniently illustrate the positional relationship of technical features and only have meaning when combined with actual usage or the specific location descriptions in the preceding text, and are not absolute positional relationships.

[0049] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0050] This invention relates to the field of electric motors, specifically to a sealing device, an electric spindle, and a CNC machine tool. The electric spindle is a new technology in the field of CNC machine tools that integrates the machine tool spindle and spindle motor. Compared to traditional mechanical spindles, electric spindles use an integrated spindle and rotor, replacing the traditional belt and gear transmission methods of mechanical spindles, greatly improving the spindle's performance at high speeds and making it more integrated and precise. In recent years, the machining field has developed rapidly, and electric spindle technology, as its core technology, has also made significant progress.

[0051] Electric spindles are precision components. Under high-speed operation, even the slightest dust entering the spindle bearings can cause spindle vibration or even seizure. Therefore, the sealing performance of the spindle largely determines its accuracy and lifespan, and proper sealing is essential in the design of electric spindle products. Since the motor of an electric spindle is built-in, moisture and dust inside the motor can deteriorate the insulation of the motor windings, even causing failure and ultimately burning out the motor. Therefore, electric spindles must be dustproof and moisture-proof. The most critical aspect is preventing cutting fluid from entering the spindle bearings during high-speed cutting. In spindle maintenance problems, bearing failure accounts for 60%–70%. Besides issues with the bearing's lifespan and precision, approximately 50% of these failures are caused by water ingress into the bearings. Therefore, the sealing structure design of electric spindles is of paramount importance.

[0052] With the development of machine tool technology and high-speed cutting technology, and the demands of practical applications, increasingly higher requirements are being placed on the performance of machine tool electric spindles. Existing electric spindle sealing structures generally have poor sealing effects. To overcome these shortcomings...

[0053] In the prior art, the locking nut is rotatably mounted on the front cover, and an elastic sealing component is set between the front cover and the locking nut to prevent dust, coolant and other impurities from entering the spindle cavity. However, it lacks axial sealing and the overall sealing performance is poor.

[0054] Another type of sealing structure prevents grease leakage. It has an outer cover oil seal between the outer bearing cover and the motor shaft, and an inner cover oil seal between the inner bearing cover and the motor shaft. The bearing is sealed on both sides by the front and rear oil seals. This sealing method is not clean, is inconvenient to assemble, and has a mediocre sealing effect.

[0055] Another type of airtight structure prevents external liquids and dust from entering by filling the sealing part with high-pressure gas and continuously expelling it through airflow. However, this method does not consider the impact of the rotation of the shaft on the airtightness, so its effectiveness is generally limited.

[0056] To improve the sealing effect of the air seal when the shaft rotates, such as Figure 1-14 As shown, the present invention provides a sealing device for sealing an electric spindle, the electric spindle including a rotating shaft 1, comprising:

[0057] Flange 2 has a flange hole 200. Flange 2 is sleeved on the rotating shaft 1 through the flange hole 200. Flange 2 is provided with an air inlet 301. The flange hole 200 includes a first inner inclined surface 501 whose diameter gradually increases from the inside to the outside. The exhaust port of the air inlet 301 is located on the first inner inclined surface 501.

[0058] The first sealing ring 401 is fitted on the rotating shaft 1 and located in the flange hole 200. The outer peripheral surface of the first sealing ring 401 includes a first outer inclined surface 601 whose diameter gradually increases from the inside to the outside. The first outer inclined surface 601 and the first inner inclined surface 501 are opposite to each other and a first gap 701 is formed between them.

[0059] In the specification and claims, "inner" and "outer" refer to the side of the flange 2 facing the inside of the motor when the sealing device is installed on the electric spindle, and the opposite side is "outer". "Sealing sleeve" means that the first sealing ring 401 is fitted onto the rotating shaft 1, and the inner surface of the first sealing ring 401 maintains a seal with the circumferential surface of the rotating shaft 1. When the electric spindle is in use, the rotating shaft 1 rotates vertically.

[0060] Inflating the first gap 701 through the air inlet 301 prevents external dust and liquid from entering the inner side of the flange 2, i.e., the side where the bearing 300 supporting the shaft 1 is located. Simultaneously, when the shaft 1 rotates, the first outer inclined surface 601 generates centrifugal motion against the dust and liquid entering the first gap 701. Due to the design of the inclination direction of the first outer inclined surface 601, the dust and liquid can move towards the discharge direction of the first gap 701 under the action of centrifugal force, thereby improving the sealing performance between the flange 2 and the shaft 1, i.e., improving the sealing performance of the electric spindle, and preventing external impurities from entering the inner side of the flange 2 and affecting the rotation of the bearing 300 supporting the shaft 1. In other words, this invention improves the sealing performance between the flange 2 and the shaft 1 through the combined effect of continuously introducing high-pressure gas into the first gap 701 and the centrifugal force of the first sealing ring. Specifically, when the shaft 1 rotates, air is injected into the first gap 701 through the air inlet 301. The gas creates a high-pressure environment in the first gap 701 and is continuously discharged from the first gap 701, thereby preventing external liquids and dust from entering the inner side of the flange 2 through the first gap 701, which is an air seal. The gas entering through the air inlet 301 can also flow inward and pass through the bearing 300, which on the one hand dissipates heat from the bearing 300, and on the other hand blows away the dust and debris generated by the wear of the bearing 300, improving the smoothness of the bearing 300's rotation. When the shaft 1 rotates, the shaft 1 drives the first sealing ring 401 to rotate. Since the diameter of the first outer inclined surface gradually increases from the inside to the outside, when the first sealing ring 401 rotates, the liquids and dust and other impurities that have entered the first gap 701 undergo centrifugal motion along the first outer inclined surface and flow outward, thereby allowing the impurities that have entered the first gap 701 to be discharged.

[0061] To ensure a high-pressure environment within the first gap 701, the flow area of ​​the first gap 701 should not exceed the flow area of ​​the air inlet 301. The first sealing ring 401 can be fixed to the rotating shaft 1 by means of threaded fastening.

[0062] When the rotating shaft 1 is installed with the bearing 300 as a support, the end of the flange 2 facing the bearing 300 abuts against the outer ring of the bearing 300, thereby pressing the flange 2 axially.

[0063] Preferred, such as Figure 2-5 As shown in Figure 8, the flange hole 200 includes a second inner inclined surface 502 whose diameter gradually increases from the inside to the outside. The second inner inclined surface 502 is located outside the first inner inclined surface 501. The small end diameter of the second inner inclined surface 502 is d1, and the large end diameter of the first inner inclined surface 501 is d2. Then d1≥d2.

[0064] The outer peripheral surface of the first sealing ring 401 includes a second outer inclined surface 602 whose diameter gradually increases from the inside to the outside. The second outer inclined surface 602 is located outside the first outer inclined surface 601 and is opposite to the second inner inclined surface 502. A second gap 702 is formed between the second outer inclined surface 602 and the second inner inclined surface 502, and the second gap 702 is connected to the first gap 701.

[0065] Gas entering the first gap 701 through the air inlet 301 enters the second gap 702. The centrifugal force generated by the rotation of the shaft 1 causes the gas entering the second gap 702 to carry liquids, dust, and other impurities from both the first and second gaps 701 outwards along the second gap 702, accelerating the discharge of impurities. The second gap 702 and the first gap 701 together form a small-gap sealing structure, further improving the sealing effect. By ensuring d1 ≥ d2, the first gap 701 is located radially outside the second gap 702 in the radial direction; under the action of centrifugal force, impurities in the first gap 701 can enter the second gap 702 more quickly; furthermore, d1 = d2 can be made.

[0066] Preferred, such as Figure 9-10 As shown, a reserved hole 302 is provided on the flange 2, and the air inlet of the reserved hole 302 is located on the second inner inclined surface 502.

[0067] Of the impurities moving outward along the second gap 702, some are discharged through the gap formed between the flange 2 and the first sealing ring 401, while others enter the reserved hole 302 under the action of centrifugal force. In particular, the impurities with larger mass are more affected by centrifugal force and are more likely to move radially outward along the shaft 1 and enter the reserved hole 302 and be temporarily stored in the reserved hole 302. This effectively speeds up the discharge of impurities from the second gap 702.

[0068] Preferred, such as Figure 4 , 5 As shown in Figure 8, the flange hole 200 includes an inner cylindrical surface 801, which is disposed between the first inner inclined surface 501 and the second inner inclined surface 502.

[0069] The outer peripheral surface of the first sealing ring 401 includes an outer cylindrical surface 802. The outer cylindrical surface 802 is disposed between the first outer inclined surface 601 and the second outer inclined surface 602 and forms a first annular gap 901 with the inner cylindrical surface 801. The first annular gap 901 is connected to the first gap 701 and the second gap 702.

[0070] When the spindle is set in the up-down direction, the impurities entering the first gap 701 are affected by gravity in addition to centrifugal force. By setting the first annular gap 901, the impurities can be discharged out faster when entering the first annular gap 901.

[0071] The first gap 701 can be connected to the external environment of the external flange 2 through a second annular gap 902, thereby forming a multi-small gap air seal structure between the first sealing ring 401 and the flange 2, further preventing external impurities from entering the inside of the flange 2.

[0072] Preferred, such as Figure 1 As shown, a plug is installed inside the reserved hole 302.

[0073] When maintaining the electric spindle, the plug can be removed to drain the impurities and cutting fluid stored in the second annular groove 2012. After the impurities and cutting fluid are drained, the plug can be put back on.

[0074] Furthermore, the plug can be a one-way valve 303, which can be opened by filling gas through the air inlet 301.

[0075] When the shaft 1 is not working, that is, when it is not rotating, the one-way valve 303 completely seals the reserved hole 302, thus preventing external impurities from entering the flange 2 through the reserved hole 302 when not in operation. When the shaft 1 rotates, gas is injected into the first gap 701 through the air inlet 301. When this gas enters the reserved hole 302, it applies pressure to the one-way valve 303, causing the one-way valve 303 to open. At this time, impurities entering the reserved hole 302 can be discharged through the one-way valve 303. Since the opening of the one-way valve 303 requires high-pressure gas inside, the one-way valve 303 can only be opened when the shaft 1 is working, thus ensuring that external impurities will not enter through the reserved hole 302 when not in operation. The one-way valve 303 is open under high pressure and closed under normal pressure, without the need for manual opening or closing of the reserved hole 302, saving manpower and avoiding liquid backflow when the reserved hole 302 is manually opened. When the impurities in the second annular groove 2012 are too large to be discharged, or when the electric spindle needs maintenance, the one-way valve 303 can be disassembled to clean the impurities in the second annular groove 2012.

[0076] Preferably, the inner end of the flange 2 is provided with a first sealing part 203, and the rotating shaft 1 is also provided with a second sealing ring 402, which is located inside the first sealing ring; the second sealing ring 402 is provided with a second sealing part 403, and a labyrinth seal is formed between the second sealing part 403 and the first sealing part 203.

[0077] "Inner end" refers to the end of the flange 2 facing the inside of the motor after the sealing device is actually installed on the motor; the second sealing ring 402 is located inside the first sealing ring, meaning that the second sealing ring 402 is closer to the motor than the first sealing ring.

[0078] The labyrinth seal formed between the second sealing part 403 and the first sealing part 203 further improves the sealing performance of the sealing device.

[0079] The second sealing ring 402 abuts against the inner ring of the bearing 300 supporting the rotating shaft 1, thereby positioning the second sealing ring 402 in the axial direction.

[0080] Preferred, such as Figure 1 , 13 As shown in Figure 14, a gap 400 is formed between the second sealing ring 402 and the first sealing ring 401. An elastic sealing ring 404 is provided in the gap 400. The elastic sealing ring 404 is fitted on the rotating shaft 1 and elastically contacts the first sealing ring 401 and the second sealing ring 402.

[0081] Due to vibration, temperature, and pressure changes, the first sealing ring 401 and the second sealing ring 402 may undergo axial deformation and displacement. To prevent compression between the first sealing ring 401 and the second sealing ring 402, a gap 400 is provided between them. An elastic sealing ring 404 is provided within the gap 400. The elastic sealing ring 404 is pre-compressed within the gap 400 and makes sealing contact with the first sealing ring 401, the second sealing ring 402, and the rotating shaft 1, ensuring sealing between the first sealing ring 401 and the elastic sealing ring 404, between the elastic sealing ring 404 and the second sealing ring 402, and between the elastic sealing ring 404 and the rotating shaft 1. Thus, when the seal between the first sealing ring 401 and the rotating shaft 1 or the second sealing ring 402 and the rotating shaft 1 is poor, external impurities and liquids will not enter the interior of the electric spindle through the gaps between the first sealing ring 401 and the rotating shaft 1 or between the second sealing ring 402 and the rotating shaft 1, thereby further improving the sealing performance of the sealing device.

[0082] When the first sealing ring 401 is fixed to the rotating shaft 1 by threads, the elastic sealing ring 404 is compressed to give the first sealing ring 401 a corresponding axial pre-compression force, which prevents the first sealing ring 401 from loosening with the rotating shaft 1 and increases the firmness and stability between the first sealing ring 401 and the rotating shaft 1.

[0083] The reduction in the gap 400 causes the elastic sealing ring 404 to be compressed and undergo radial deformation, leading to contact between the elastic sealing ring 404 and the inner wall surface of the flange hole 200. When the elastic sealing ring 404 rotates with the rotating shaft 1, it will rub against the inner wall surface of the flange hole 200. When the elastic sealing ring 404 rubs, the temperature rises, causing the elasticity of the elastic sealing ring 404 to decrease, which in turn leads to a decrease in the sealing performance of the elastic sealing ring 404 at the gap 400. To avoid this phenomenon, the thickness of the radial outer edge of the elastic sealing ring 404 is reduced. Thus, when the elastic sealing ring 404 is subjected to axial compression, the overall radial deformation of the elastic sealing ring 404 is smaller, thereby avoiding contact between the elastic sealing ring 404 and the inner wall surface of the flange hole 200, ensuring the elastic performance and sealing performance of the elastic sealing ring 404, and improving the sealing performance of the elastic sealing ring 404 at the gap 400.

[0084] The cross-section of the elastic sealing ring 404 can be designed as a right trapezoid, with the inclined waist facing the inner wall of the flange hole 200, and the straight waist sealing sleeve is installed on the rotating shaft 1; furthermore, the angle between the inclined waist and one of the bottom edges is β, 30°≤β≤60°.

[0085] A third annular gap 903 can be designed between the second gap 702 and the interval 400 to guide the airflow, so that the gas flows inward and blows quickly over the bearing 300, thereby radially cooling the bearing 300 and blowing away the dust on the bearing 300.

[0086] Based on the order in which external impurities can enter the inner side of flange 2, this sealing device provides a three-stage seal. The first-stage seal includes a first sealing ring 401 and an internal structure of the flange hole 200 radially opposite to the first sealing ring 401; the second-stage seal includes an elastic sealing ring 404; and the third-stage seal includes a labyrinth seal. This three-stage seal effectively prevents external liquids and dust from entering the inner side of flange 2 and adversely affecting bearing 300, thus improving the service life of bearing 300 and increasing the working efficiency and accuracy of shaft 1. When this sealing device is applied to an electric spindle, it effectively prevents dust and cutting fluid from entering the spindle, thereby ensuring the spindle's accuracy and extending its service life. The three-stage seal, composed of different sealing components, facilitates disassembly and maintenance, significantly improving assembly efficiency.

[0087] Preferred, such as Figure 1 As shown, the sealing device also includes an end cap 500, which is fitted onto the rotating shaft 1 through a through hole and abuts against the outer end face of the flange 2.

[0088] "Outer end" refers to the end of the sealing device that faces away from the inside of the motor when it is installed on the electric spindle; the end cover 500 can protect the first sealing ring 401 and prevent the first sealing ring 401 from being accidentally hit, which would cause the sealing performance to decrease.

[0089] like Figure 1 As shown, the end cover 500 can be connected to the bearing seat 505 by bolts 504 passing through the end cover 500 and the flange 2. The axial thickness of the flange 2 can be adjusted by rotating the bolts 504, thereby adjusting the size of the small gap sealing structure formed between the first sealing ring 401 and the flange 2, and adjusting the size of the gap of the labyrinth seal structure formed between the flange 2 and the second sealing ring 402. On the one hand, this allows the electric spindle to adapt to different working environments. On the other hand, increasing the size of the small gap sealing structure formed between the first sealing ring 401 and the flange 2, and increasing the size of the gap of the labyrinth seal structure formed between the flange 2 and the second sealing ring 402, facilitates quick cleaning during maintenance.

[0090] To facilitate the adjustment of the axial thickness of flange 2, flange 2 can be made of metals with a certain degree of ductility, such as copper or aluminum. By using a ductile metal to make flange 2, the rotation of the adjustable bolt 504 can change the size of the deformation caused by the compression of flange 2, thereby enabling a wider range of adjustment of the size of the small gap sealing structure formed between the first sealing ring 401 and flange 2, and adjusting the size of the gap of the labyrinth sealing structure formed between flange 2 and second sealing ring 402.

[0091] Furthermore, such as Figure 1 As shown, a relief groove 503 can be provided on the side of the end cover 500 facing the flange 2. By providing relief groove 503, the end cover 500 and the first sealing ring 401 do not come into contact, so that the end cover 500 will not squeeze the first sealing ring 401. This avoids the first sealing ring 401 interfering with the end cover 500 when adjusting the axial thickness of the flange 2, making it impossible to effectively squeeze the flange 2.

[0092] Preferred, such as Figure 7 As shown, flange 2 includes flange body 201 and gas sealing ring 202, and flange body 201 is provided with an annular relief groove;

[0093] The inner wall of the annular relief groove is provided with a first annular groove 2011; the air inlet 301 connects the outside of the flange body 201 and the first annular groove 2011; the gas sealing ring 202 is provided with multiple air blowing holes 2021; the gas sealing ring 202 is sealed in the annular relief groove; the air blowing holes 2021 connect the first annular groove 2011 and the inner hole of the gas sealing ring 202.

[0094] And / or,

[0095] The inner wall of the annular relief groove is provided with a second annular groove 2012; the reserved hole 302 connects the outside of the flange body 201 and the second annular groove 2012; the gas sealing ring 202 is provided with multiple drain holes 2022; the gas sealing ring 202 is sealed in the annular relief groove; the drain holes 2022 connect the second annular groove 2012 and the inner hole of the gas sealing ring 202.

[0096] Gas enters the first annular groove 2011 through the inflation hole 301, causing the gas pressure and flow rate to be evenly distributed within the annular groove. After the gas pressure and flow rate are evenly distributed, the gas is discharged into the first gap 701 through the blowing hole 2021 on the airtight ring 202, ensuring the circumferential air pressure and flow rate balance within the first gap 701 and further improving the blocking effect of the first gap 701 on impurities. When the gas entering the first gap 701 flows into the second gap 702, it blows liquid or other impurities into multiple drain holes 2022 for temporary storage, further accelerating the discharge of impurities from the second gap 702.

[0097] Preferred, such as Figure 4 and Figure 11 As shown, the first inner inclined surface 501 and the first outer inclined surface 601 are parallel to each other and make an angle α with the axis of rotation 1. Therefore, 30°≤α≤60°.

[0098] Force analysis is performed on the liquid entering the flange hole 200. Under high-speed rotation, the liquid or dust and other impurities are subjected to their own weight mg and radial centrifugal force F. According to the formula F=mω 2 r, Calculations show that when 30°≤α≤60°, the liquid is most affected by these two forces.

[0099] Secondly, the present invention provides an electric spindle, comprising a rotating shaft 1 and the aforementioned sealing device.

[0100] The electric spindle has a good sealing effect, high assembly efficiency, and is easy to disassemble and maintain.

[0101] Thirdly, the present invention proposes a CNC machine tool, including an electric spindle.

[0102] The machining accuracy of this CNC machine tool can be guaranteed, and its service life can be extended.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A sealing device for the sealing of an electric spindle comprising a rotating shaft (1), characterized in that, The application relates to a flange plate (2) with a flange hole (200), wherein the flange plate (2) is sleeved on the rotating shaft (1) through the flange hole (200), the flange plate (2) is provided with an inflation hole (301), the flange hole (200) comprises a first inner inclined surface (501) with gradually increased diameter from inside to outside, and the exhaust port of the inflation hole (301) is located on the first inner inclined surface (501); a first sealing ring (401) is sealingly sleeved on the rotating shaft (1) and located in the flange hole (200), the outer circumferential surface of the first sealing ring (401) comprises a first outer inclined surface (601) with gradually increased diameter from inside to outside, the first outer inclined surface (601) is opposite to the first inner inclined surface (501) and a first gap (701) is formed between the first outer inclined surface (601) and the first inner inclined surface (501); the flange hole (200) comprises a second inner inclined surface (502) with gradually increased diameter from inside to outside, the second inner inclined surface (502) is located outside the first inner inclined surface (501); the outer circumferential surface of the first sealing ring (401) comprises a second outer inclined surface (602) with gradually increased diameter from inside to outside, the second outer inclined surface (602) is located outside the first outer inclined surface (601) and opposite to the second inner inclined surface (502), a second gap (702) is formed between the second outer inclined surface (602) and the second inner inclined surface (502), and the second gap (702) is communicated with the first gap (701); the flange plate (2) is provided with a reserved hole (302), and the inlet of the reserved hole (302) is located on the second inner inclined surface (502). The small end diameter of the second inner inclined surface (502) is d1, the large end diameter of the first inner inclined surface (501) is d2, and d1>=d2. The flange hole (200) comprises an inner cylindrical surface (801) arranged between the first inner inclined surface (501) and the second inner inclined surface (502); The outer circumferential surface of the first sealing ring (401) comprises an outer cylindrical surface (802) arranged between the first outer inclined surface (601) and the second outer inclined surface (602) and forming a first annular gap (901) with the inner cylindrical surface (801), and the first annular gap (901) is communicated with the first gap (701) and the second gap (702). The reserved hole (302) is provided with a plug.

2. The sealing device of claim 1, wherein The inner end of the flange plate (2) is provided with a first sealing part (203), the rotating shaft (1) is further provided with a second sealing ring (402) in a sealing mode, the second sealing ring (402) is located inside the first sealing ring (401), the second sealing ring (402) is provided with a second sealing part (403), and the second sealing part (403) and the first sealing part (203) form a labyrinth seal.

3. The sealing device of claim 1, wherein ​ ​ 4. The sealing device of claim 1, wherein ​ 5. The sealed device of claim 1, wherein, ​ 6. The sealing device of claim 5, wherein The second sealing ring (402) and the first sealing ring (401) form a gap (400), and an elastic sealing ring (404) is arranged in the gap (400), the elastic sealing ring (404) is sleeved on the rotating shaft (1) and is in elastic contact with the first sealing ring (401) and the second sealing ring (402).

7. The sealed device of claim 1, wherein, The sealing device further comprises an end cover (500), the end cover (500) is sleeved on the rotating shaft (1) through a through hole and is fixed on the outer end surface of the flange plate (2).

8. The sealing device of claim 7, wherein, The flange plate (2) comprises a flange body (201) and a gas sealing ring (202), the flange body (201) is provided with an annular accommodation groove; The inner wall of the annular accommodation groove is provided with a first annular groove (2011); the inflation hole (301) is communicated with the outside of the flange body (201) and the first annular groove (2011), the gas sealing ring (202) is provided with a plurality of air blowing holes (2021), the gas sealing ring (202) is sealingly arranged in the annular accommodation groove, and the air blowing hole (2021) is communicated with the first annular groove (2011) and the inner hole of the gas sealing ring (202); And / or, The inner wall of the annular accommodation groove is provided with a second annular groove (2012); the reserved hole (302) is communicated with the outside of the flange body (201) and the second annular groove (2012), the gas sealing ring (202) is provided with a plurality of liquid discharge holes (2022), the gas sealing ring (202) is sealingly arranged in the annular accommodation groove, and the liquid discharge hole (2022) is communicated with the second annular groove (2012) and the inner hole of the gas sealing ring (202).

9. The sealing device according to any one of claims 1-8, characterized in that The first inner inclined surface (501) and the first outer inclined surface (601) are parallel to each other and form an angle α with the axis of the rotating shaft (1), and 30°≤α≤60°.

10. An electric spindle, characterized by The sealing device comprises the rotating shaft (1) and any one of claims 1-9.

11. A numerically controlled machine tool, characterized by comprising: The electric spindle comprises the electric spindle of claim 10. The electric spindle comprises the electric spindle of claim 10.

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