A gas seal structure, electric spindle and machine tool equipment

Abstract

This application belongs to the field of electric spindle technology, specifically relating to an air-sealing structure, an electric spindle, and machine tool equipment. The air-sealing structure includes a mounting base, a stationary ring, and a rotating ring. The mounting base is located at the front end of the bearing assembly and has an air passage connecting to the outside. The stationary ring and the mounting base enclose a receiving cavity. The rotating ring is sleeved on the rotating shaft and housed within the receiving cavity. An annular air passage connecting the air passage and the air gap is provided at the rear end of the stationary ring. High-pressure airflow forms a continuous closed-loop airflow barrier around the outer periphery of the rotating ring through the annular air passage. This application forms a uniform high-pressure airflow around the entire ring by setting an annular air passage in the stationary ring, achieving 360° airtight protection without dead angles. The annular air passage facilitates the need for quick clearing of blockages after the stationary ring is disassembled, eliminating the need to replace parts. Customers can perform maintenance themselves, which helps improve production efficiency and reduce maintenance and production costs.

Description

Technical Field

[0001] This application belongs to the field of electric spindle technology, specifically relating to an air-sealed structure, an electric spindle, and machine tool equipment. Background Technology

[0002] Electric spindles are one of the core functional components of machine tools, and gas sealing technology is widely used in this field. Existing gas seal structures are relatively complex, typically using multiple tiny vent holes or segmented V-grooves evenly distributed on the stationary ring to generate high-speed airflow. Due to the limited number of evenly distributed holes or grooves, the high-speed airflow pressure distribution is uneven, and there are multiple sealing blind spots on the outer circumference of the moving ring. Metal dust, cutting fluid, oil mist, etc., can easily seep into the spindle from these blind spots, resulting in poor sealing protection for the electric spindle.

[0003] Furthermore, after long-term processing, the holes and grooves of existing air seals are easily clogged by oil and metal debris, leading to airflow attenuation and seal failure. Once blockage occurs, the entire machine must be disassembled and the entire set of sealing components replaced, resulting in high maintenance costs. Moreover, maintenance work requires professional repair personnel, with long repair cycles and uncontrollable repair time, affecting production output and severely impacting production efficiency, making it difficult to meet users' production and usage needs. Summary of the Invention

[0004] The purpose of this application is to solve at least one of the technical problems existing in the prior art, and to provide an air-sealing structure, electric spindle and machine tool equipment, which forms a uniform high-pressure airflow around the entire circle by setting an annular air passage through the stationary ring, so as to achieve 360° airtight protection without dead angles. The setting of the annular air passage facilitates the need to quickly clear blockages after the stationary ring is disassembled, without the need to replace parts. Customers can complete the maintenance themselves, which helps to improve production efficiency and reduce maintenance and production costs.

[0005] The technical solution adopted by this application to solve its technical problem is: In a first aspect, an air seal structure is provided for installation on the front end of a bearing assembly, the bearing assembly being fitted onto the outer periphery of a rotating shaft. The air seal structure includes a mounting base, a stationary ring, and a rotating ring. The mounting base is installed on the front end of the bearing assembly and has an air passage communicating with the outside. The stationary ring is installed on the front end of the mounting base and together with the mounting base forms a receiving cavity. The rotating ring is fitted onto the outer periphery of the rotating shaft and is located within the receiving cavity. An air gap is formed between the stationary ring and the mounting base and the rotating ring. The stationary ring has an annular air passage located on the outer periphery of the moving ring at its rear end. The annular air passage connects the air path channel and the air gap, so that the airflow entering the air path channel can form a closed-loop continuous airflow on the outer periphery of the moving ring through the annular air passage.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the rear end of the stationary ring is provided with a protrusion extending into the mounting base. The protrusion is provided with a stepped structure. The stepped structure has a first end face and a second end face distributed sequentially from the inside to the outside. The second end face abuts against the mounting base. The first end face is lower than the second end face. The first end face and the mounting base enclose the annular air passage.

[0007] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the mounting base is provided with an annular transition groove at the outlet of the gas passage, and the gas passage is connected to the annular gas channel through the annular transition groove.

[0008] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the mounting base forms an inner annular rib on the inner side of the annular transition groove and an outer annular rib on the outer side of the annular transition groove. The end face of the outer annular rib is used to abut against the second end face. The first end face extends radially from the annular transition groove to the front of the inner annular rib, so as to form the annular air passage with the end face of the inner annular rib.

[0009] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the annular air passage is perpendicular to the outer circumferential surface of the moving ring.

[0010] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the width of the air gap formed by the stationary ring in the circumferential direction of the moving ring is 0.1 mm to 0.5 mm.

[0011] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the air gap formed between the rear end of the moving ring and the mounting base is labyrinthine.

[0012] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the mounting base is provided with a connecting base on the outer periphery of the protrusion, the mounting base is detachably connected to the stationary ring through the connecting base, and a sealing ring is provided between the connecting base and the protrusion.

[0013] In a second aspect, an electric spindle includes a rotating shaft, a bearing assembly, and an air seal structure as described in any implementation of the first aspect, wherein the bearing assembly is sleeved on the outer periphery of the rotating shaft, and the air seal structure is disposed at the front end of the bearing assembly and is sleeved on the outer periphery of the rotating shaft via the moving ring.

[0014] In a second aspect, a machine tool device includes an electric spindle as described in any implementation of the second aspect.

[0015] One of the above technical solutions has at least one of the following advantages or beneficial effects: The air seal structure of this application replaces the traditional uniformly distributed micropore and segmented V-groove air outlet structure by setting an annular air channel at the rear end of the stationary ring. The airflow is uniformly output along the entire circle of the moving ring, with no airflow blind spots, and it completely blocks metal dust, cutting fluid, and oil mist from entering the bearing, greatly improving the airtight protection performance. At the same time, since impurities and oil stains mainly accumulate between the front channel position of the stationary ring and the moving ring and the annular air channel (that is, between the air gap in front of the annular air channel and the annular air channel), when the air seal performance of the product fails, only the stationary ring needs to be removed to clean the oil stains on the surface of the moving ring and the stationary ring and the annular air channel, and the air seal performance will be restored immediately without the need to replace any sealing parts. Customers can complete the maintenance independently, which significantly reduces maintenance costs and shortens the equipment downtime cycle. In addition, the air seal structure of this application has no small, easily clogged channel structure, and it is not easy to have airflow attenuation or seal failure failure during long-term operation, thus reducing the spindle failure rate. Attached Figure Description

[0016] The following description, in conjunction with the accompanying drawings, further illustrates this application: Figure 1 This is a schematic diagram of the structure of an electric spindle according to an embodiment of this application; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 yes Figure 1 A cross-sectional schematic diagram of the mounting base of one embodiment is shown; Figure 4 yes Figure 1 The diagram shows a structural schematic of the stationary ring in one embodiment. Figure 5 This is a schematic diagram showing the uneven and discontinuous pressure distribution at the gas seal outlet in the existing design. Figure 6 This is a schematic diagram showing a uniform and continuous pressure distribution at the gas seal outlet in this application.

[0017] Explanation of icon numbers: 1-Stationary ring; 11-Protrusion; 12-Stepped structure; 121-First end face; 122-Second end face; 13-Annular airway; 2-Mounting base; 21-Air passage; 22-Annular transition groove; 23-Inner annular rib; 24-Outer annular rib; 25-Connecting base; 26-Sealing ring; 3-Dynamic ring; 4-Rotating shaft; 5-Bearing assembly; 6-Air gap; 7-Electric spindle; 8-Connecting component. Detailed Implementation

[0018] This section will describe in detail the specific embodiments of this application. Preferred embodiments of this application are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of this application, but they should not be construed as limiting the scope of protection of this application.

[0019] In this application, when directions (up, down, left, right, front, and back) are described, it is only for the purpose of describing the technical solution of this application, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on this application.

[0020] In this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number; "above," "below," "within," etc. are understood to include the stated number. In the description of this application, the terms "first" and "second" are used only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0021] In this application, unless otherwise explicitly defined, the terms "setup," "installation," and "connection" should be interpreted broadly. For example, they can refer to direct connection or indirect connection through an intermediate medium; they can refer to fixed connection, detachable connection, or integral molding; they can refer to mechanical connection, electrical connection, or connection capable of mutual communication; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this application based on the specific content of the technical solution.

[0022] See Figure 1 and Figure 2 This embodiment provides an air seal structure, which is suitable for sealing and protecting the front end of the electric spindle bearing assembly. The bearing assembly 5 is sleeved on the outer circumference of the rotating shaft 4. The rotating shaft 4 is the rotating output shaft of the electric spindle. The motor rotor is installed in the middle section of the rotating shaft 4. The motor stator is fixed inside the spindle housing. When the stator is energized, it drives the rotor and the rotating shaft 4 to rotate synchronously at high speed.

[0023] In this embodiment, the gas seal core includes three main components: mounting base 2, stationary ring 1, and rotating ring 3. The mounting base 2 is fixedly installed on the front end face of the bearing assembly 5 facing the processing side. An air passage 21 is opened inside the mounting base 2. One end of the air passage 21 is connected to the high-pressure air source outside the workshop, and the other end is connected to the internal sealing cavity. The stationary ring 1 is assembled and fixed at the front end of the mounting base 2, and together with the mounting base 2, they form an annular closed receiving cavity.

[0024] The rotating ring 3 is tightly fitted to the outer circumference of the rotating shaft 4 and rotates synchronously with the rotating shaft 4 at high speed. The rotating ring 3 is housed entirely within the receiving cavity. The inner ring surface of the stationary ring 1 facing the rotating ring 3 and the inner side wall of the mounting base 2 are respectively reserved with the rotating ring 3 to form an air gap 6. An annular air passage 13 is provided at the rear end of the stationary ring 1 at a position corresponding to the outer circle of the rotating ring 3. One side of the annular air passage 13 is connected to the air passage 21 of the mounting base, and the other side is connected to the air gap 6.

[0025] After the external high-pressure compressed air is input through the air passage 21, it is all introduced into the annular air passage 13 and output evenly along the entire circle of the annular air passage 13, forming a continuous and uninterrupted closed-loop airflow barrier around the outer periphery of the moving ring 3.

[0026] See Figure 5 Traditional stationary rings use dispersed micropores and segmented V-grooves for air outlet, resulting in segmented airflow and uneven pressure. A blind zone without airflow sealing exists on the outer circumference of the moving ring, leading to uneven and discontinuous pressure distribution at the air seal outlet, i.e., the front outlet of air gap 6, resulting in unsatisfactory sealing and protection. (See also...) Figure 6 In this embodiment, a complete and continuous annular air passage is set at the rear end of the stationary ring, and the output airflow fully covers the outer circumference of the moving ring without any sealing dead corners. The pressure distribution at the air seal outlet, which is also the front outlet of the air gap 6, is continuous and uniform. Furthermore, the annular air passage has no small pores, making it less prone to being blocked by cutting oil or metal powder, thus reducing the spindle failure rate.

[0027] The air seal structure of this application replaces the traditional uniformly distributed micropore and segmented V-groove air outlet structure by setting an annular air passage 13 at the rear end of the stationary ring 1. The airflow is evenly output along the entire circle of the moving ring, with no airflow blind spots, and it completely blocks metal dust, cutting fluid, and oil mist from entering the bearing, greatly improving the airtight protection performance. At the same time, since impurities and oil stains mainly accumulate between the front channel position of the stationary ring 1 and the moving ring 3 and the annular air passage 13 (that is, between the air gap 6 in front of the annular air passage 13 and the annular air passage 13), when the air seal performance fails, only the stationary ring 1 needs to be removed to clean the oil stains on the surface of the moving ring 3, the stationary ring 1, and the annular air passage 13, and the air seal performance will be restored immediately without the need to replace any sealing parts. Customers can complete the maintenance independently, which significantly reduces maintenance costs and shortens the equipment downtime cycle. In addition, the air seal structure of this application has no small, easily clogged channels, and is less prone to airflow attenuation and seal failure during long-term operation, reducing the spindle failure rate.

[0028] Based on the above embodiments, see Figures 1 to 4 The rear end of the static ring 1 is provided with a protrusion 11 extending into the mounting base 2. The protrusion 11 is provided with a stepped structure 12. The stepped structure 12 has a first end face 121 and a second end face 122 distributed sequentially from the inside to the outside. The second end face 12 abuts against the mounting base 2. The first end face 121 is lower than the second end face 122. The first end face 121 and the mounting base 2 form an annular air passage 13.

[0029] The stepped structure can be machined in a single turning operation, resulting in low processing costs. Furthermore, by adjusting the downward height of the first end face 121, the flow cross-sectional area of ​​the annular air passage 13 can be changed, thereby achieving free adjustment of the air seal airflow strength. This adapts to various processing conditions, including dry and wet processes, and meets the different production needs of different customers.

[0030] Furthermore, subsequent cleaning operations can be performed by quickly wiping the stepped structure after removing the stationary ring 1, avoiding the cleaning difficulties caused by the multi-groove design in the existing design, as well as the difficulties in operation and high costs caused by the need to replace parts once the air seal fails.

[0031] Furthermore, the mounting base 2 is provided with an annular transition groove 22 at the outlet of the gas passage 21, and the gas passage 21 is connected to the annular gas channel 13 through the annular transition groove 22. The high-pressure gas first flows into the annular transition groove 22 to complete the circumferential pressure buffering and equal distribution, and then flows into the annular gas channel 13, avoiding local pressure imbalance in the annular gas channel caused by single-point air intake, further improving the uniformity of airflow around the moving ring, and strengthening the airtight barrier effect.

[0032] Furthermore, the mounting base 2 forms an inner annular rib 23 on the inner side of the annular transition groove 22 and an outer annular rib 24 on the outer side of the annular transition groove 22. The end face of the outer annular rib 24 is used to abut against the second end face 122. The first end face 121 extends radially from the annular transition groove 22 to the front of the inner annular rib 23, so as to form an annular air passage 13 with the end face of the inner annular rib 23.

[0033] The annular air passage 13 is formed by the inner annular rib 23 and the outer annular rib 24 together with the first end face 121 of the stationary ring. The inner and outer ribs can form a radial limit and blockage of the airflow, preventing high-pressure gas from radially depressurizing from the inner and outer sides of the annular air passage 13, ensuring that the airflow is directed towards the moving ring 3, so that the airflow output from the annular air passage 13 is uniform and continuous. At the same time, the forming method has a simple processing procedure. During the production process, only the end faces of the inner annular rib 23 at the rear end of the stationary ring 1 and the mounting base 2 at the corresponding height need to be processed to form a complete air passage. The processing difficulty is lower, the forming efficiency is higher, and the overall processing and manufacturing cost is effectively reduced.

[0034] Furthermore, the annular air passage 13 is perpendicular to the outer circumferential surface of the moving ring 3. The high-pressure airflow is injected radially and vertically onto the outer circumferential wall of the moving ring 3, which can prevent the airflow from being axially deflected and dispersed, avoid the attenuation of the airflow pressure inside the air gap 6, and stably maintain the overall strength of the annular airflow barrier on the outer circumference of the moving ring 3. At the same time, in conjunction with the centrifugal force generated by the high-speed rotation of the moving ring 3, the cutting fluid and metal debris falling on the surface of the moving ring 3 are blown away by the airflow and centrifugal force and removed outward, forming a double foreign matter barrier protection, which greatly improves the overall air seal effect.

[0035] In some embodiments, the width of the air gap 6 formed by the stationary ring 1 and the rotating ring 3 in the circumferential direction is 0.1 mm to 0.5 mm; this range is a reasonable gap to adapt to the non-contact seal of the spindle, which avoids thermal expansion and vibration caused by the high-speed operation of the spindle from rubbing against the stationary and rotating rings, and can maintain a stable high-pressure air curtain output from the annular air passage.

[0036] In some embodiments, see Figure 1 and Figure 2 The air gap 6 formed between the rear end of the moving ring 3 and the mounting base 2 is labyrinth-shaped; the airflow output by the annular air passage 13 located at the front end of the labyrinth-shaped air gap 6 can block most external foreign objects, and a small number of tiny particles will turn back and settle in the labyrinth-shaped air gap 6, forming a second layer of passive sealing protection, further reducing the probability of dust and water ingress failure of the bearing assembly 5.

[0037] In some embodiments, the mounting base 2 is provided with a connecting base 25 on the outer periphery of the protrusion 11. The mounting base 2 is detachably connected to the stationary ring 1 through the connecting base 25. Specifically, it can be connected between the connecting base 25 and the stationary ring 1 by a connector 8 arranged in the front-back direction. A sealing ring 26 is provided between the connecting base 25 and the protrusion 11.

[0038] When removing the stationary ring 1, the connecting piece 8 between the connecting base 25 and the stationary ring 1 can be loosened, allowing the stationary ring 1 to be pulled forward without disassembling the spindle core components such as the shaft and bearings. The sealing ring 26 seals the assembly gap between the connecting base 25 and the protrusion 11, preventing high-pressure gas leakage and stabilizing the internal air pressure of the annular air passage 13. When the annular air passage 13 accumulates oil and causes a decrease in sealing performance, performance can be restored simply by disassembling and wiping the stepped structure of the stationary ring. No sealing components need to be replaced throughout the process, and end users can perform maintenance independently.

[0039] See Figure 1 This embodiment provides an electric spindle 7, including a rotating shaft 4, a bearing assembly 5, and an air seal structure as described in any of the above embodiments. The bearing assembly 5 is sleeved on the outer periphery of the rotating shaft 4 to support the high-speed rotation of the rotating shaft 4. The electric spindle has a built-in stator and rotor, with the rotor fixedly sleeved on the rotating shaft 4 and rotating synchronously. The air seal structure is located at the front end of the bearing assembly 5 and is sleeved on the outer periphery of the rotating shaft 4 through a moving ring 3. The annular air passage 13 of the air seal structure continuously outputs a uniform high-pressure airflow, isolating cutting dust and cutting fluid from entering the spindle, protecting the bearings and the built-in motor, and extending the service life of the entire machine.

[0040] This embodiment provides a machine tool, including the electric spindle 7 in the above embodiment; the machine tool is a CNC machining center, CNC milling machine or other metal cutting equipment, the electric spindle 7 is assembled on the machine tool slide as a core cutting component, and the front end air seal of the electric spindle 7 forms a continuous airtight barrier by relying on the annular air passage 13, which ensures the long-term high-precision and stable operation of the electric spindle and reduces the equipment operation and maintenance cost.

[0041] In the description of this specification, references to terms such as "example," "embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An air-sealing structure for mounting on the front end of a bearing assembly, the bearing assembly being fitted onto the outer circumference of a rotating shaft, characterized in that, The air seal structure includes a mounting base, a stationary ring, and a rotating ring. The mounting base is installed at the front end of the bearing assembly and has an air passage connecting to the outside. The stationary ring is installed at the front end of the mounting base and together with the mounting base, they form a receiving cavity. The rotating ring is used to fit around the outer circumference of the rotating shaft and is located within the receiving cavity. An air gap is formed between the stationary ring and the mounting base and the rotating ring. The stationary ring has an annular air passage located on the outer periphery of the moving ring at its rear end. The annular air passage connects the air path channel and the air gap, so that the airflow entering the air path channel can form a closed-loop continuous airflow on the outer periphery of the moving ring through the annular air passage.

2. The gas seal structure according to claim 1, characterized in that, The rear end of the stationary ring is provided with a protrusion extending into the mounting base. The protrusion has a stepped structure, and the stepped structure has a first end face and a second end face distributed sequentially from the inside to the outside. The second end face abuts against the mounting base, and the first end face is lower than the second end face. The first end face and the mounting base form the annular air passage.

3. The gas seal structure according to claim 2, characterized in that, The mounting base is provided with an annular transition groove at the outlet of the gas passage, and the gas passage is connected to the annular gas channel through the annular transition groove.

4. The gas seal structure according to claim 3, characterized in that, The mounting base forms an inner annular rib on the inner side of the annular transition groove and an outer annular rib on the outer side of the annular transition groove. The end face of the outer annular rib is used to abut against the second end face. The first end face extends radially from the annular transition groove to the front of the inner annular rib, so as to form the annular air passage with the end face of the inner annular rib.

5. The gas seal structure according to claim 4, characterized in that, The annular air passage is perpendicular to the outer circumferential surface of the moving ring.

6. The gas seal structure according to claim 1 or 5, characterized in that, The air gap width formed by the stationary ring in the circumferential direction of the moving ring is 0.1 mm to 0.5 mm.

7. The gas seal structure according to claim 1, characterized in that, The air gap formed between the rear end of the moving ring and the mounting base is labyrinthine.

8. The gas seal structure according to claim 2, characterized in that, The mounting base has a connecting base on the outer periphery of the protrusion. The mounting base is detachably connected to the stationary ring through the connecting base. A sealing ring is provided between the connecting base and the protrusion.

9. An electric spindle, characterized in that, The device includes a rotating shaft, a bearing assembly, and an air seal structure as described in any one of claims 1 to 8, wherein the bearing assembly is sleeved on the outer periphery of the rotating shaft, and the air seal structure is located at the front end of the bearing assembly and is sleeved on the outer periphery of the rotating shaft via the moving ring.

10. A machine tool device, characterized in that, Includes the electric spindle as described in claim 9.

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