An active axial combined air bearing

Abstract

The present invention discloses an active shaft-type combined air bearing, which includes an outer bearing seat, an inner bearing seat, a roller shaft, and a number of ball bearings. The inner bearing seat includes an outer ball bearing shaft seat, an inner air shaft seat, and an extended coaxial seat. One end of the extended coaxial seat is connected to a driving motor. When the roller shaft starts to rotate, the driving motor also starts to rotate, but the rotation direction of the driving motor is opposite to the rotation direction of the roller shaft, which increases the relative rotation speed of the roller shaft during takeoff, enabling the roller shaft in the foil ring to take off faster and at a lower rotation speed. When the rotation speed of the roller shaft gradually increases after takeoff, the driving motor gradually decelerates and rotates in the reverse direction, reducing the relative rotation speed between the roller shaft and the inner bearing seat. The original maximum rotation speed of the rotating shaft minus the rotation speed of the inner bearing seat in the same direction is the actual relative rotation speed of the rotating shaft relative to the inner bearing seat, reducing the relative friction and heat generation between the rotating shaft and the inner bearing seat, reducing wear and tear, and improving the service life and quality of the overall product.

Description

Technical Field

[0001] The present invention relates to the technical field of using foil bearings, and specifically to an active shaft-type combined air bearing. Background Art

[0002] Air bearings have been widely used in the industrial field. For conventional mechanically contacting rolling bearings, the higher the rotational speed, the higher the requirements for bearing accuracy, lubrication, etc., and the shorter the service life. Air bearings suspend the spindle in the air without mechanical contact and use clean air as a lubricant, reducing the wear to a minimum. Therefore, they can provide extremely high radial and axial rotational accuracies and show unique advantages in high-speed, low-friction, high-temperature, low-temperature, and radioactive environments.

[0003] However, the take-off speed and the maximum speed are challenges that air bearings need to face in different application conditions. The higher the take-off speed, the higher the probability of contact wear between the foil and the shaft. Similarly, the higher the maximum speed, the higher the bearing friction loss and the greater the bearing heat generation.

[0004] Problems to be Solved by the Invention

[0005] Air bearings require a relatively high rotational speed during take-off. From the start of shaft rotation until take-off, the shaft contacts the surrounding foil, and continuous high-speed friction generates a large amount of heat. At the same time, even if wear-resistant materials are coated on the surfaces of the shaft and the foil, wear still occurs on the shaft and the foil. Heat and wear account for a relatively large proportion of the factors causing failure, and it is necessary to control the heat generation and wear of the shaft and the foil from aspects such as structural design, materials, and processes.

[0006] Although the air bearing moves under the wrap of the air film after take-off and has no contact with the foil, the high-speed shaft still rubs against the high-speed air film, and the high-speed air film still rubs against the bearing. According to the power loss formula caused by bearing friction, the power loss of the bearing is positively correlated with the total frictional torque and rotational speed of the bearing. Among these two factors, it is easier to control the rotational speed than to control the total frictional torque. Summary of the Invention

[0007] The purpose of the present invention is to improve the problem of easy damage of existing foil bearings. By combining a foil bearing, a ball, and a motor, the bearing housing of the foil bearing is rotated, enabling the rollers in the foil ring to take off faster and at a lower rotational speed, and the high-speed roller rotates in the same direction as the low-speed rotating inner bearing housing, reducing the actual relative rotational speed of the rotating shaft, reducing the relative friction and heat generation between the rotating shaft and the inner bearing housing, reducing wear and tear, and improving the service life and quality of the overall product.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] An active shaft-type combined air bearing, comprising an outer bearing seat, an inner bearing seat, a roller and a number of balls. The inner bearing seat includes an outer ball shaft seat, an inner air shaft seat and an extended coaxial seat. Each ball is located between the outer bearing seat and the outer ball shaft seat. A foil ring is provided on the inner wall of the inner air shaft seat. The roller is located within the foil ring. One end of the extended coaxial seat is connected to a driving motor. When the roller starts to rotate, the driving motor also starts to rotate, but the rotation direction of the driving motor is opposite to that of the roller, driving the inner bearing seat to rotate in the reverse direction. At this time, the relative rotational speed between the roller and the inner bearing seat is the sum of their speeds, which increases the relative rotational speed for the roller to take off. The gas outer layer of the air film within the roller rotates following the inner air shaft seat under the action of two opposite forces, and the inner layer rotates following the roller. The relative flow rate of the gas becomes faster (the air film flow requires special design to ensure stable operation of the air film and controlled energy consumption within the air film). The static pressure increases, enabling the roller in the foil ring to take off faster and at a lower rotational speed. When the rotational speed of the roller gradually increases after takeoff, the driving motor gradually decelerates and rotates in the reverse direction, so that when the roller rotates at a high speed, the driving inner bearing seat and the roller can maintain the same rotational direction. The roller rotating at a medium to high speed rotates in the same direction as the inner bearing seat rotating at a low speed, thereby reducing the relative rotational speed between the roller and the inner bearing seat. The original maximum rotational speed of the rotating shaft minus the rotational speed of the inner bearing seat in the same direction is the actual relative rotational speed of the rotating shaft relative to the inner bearing seat, reducing the relative friction and heat generation between the rotating shaft and the inner bearing seat, reducing wear and tear, and improving the service life and quality of the overall product.

[0010] Preferably, the driving motor includes a motor rotating shaft and a motor stator, and the extended coaxial seat is connected to the motor rotating shaft.

[0011] Preferably, during the startup stage of the driving motor: the rotation direction of the motor rotating shaft is opposite to that of the roller. After the roller takes off and stabilizes: the motor rotating shaft gradually decelerates and rotates in the reverse direction, and is the same as the rotation direction of the roller.

[0012] Preferably, the foil ring is composed of at least three independent rigid foils connected end to end in sequence.

[0013] Preferably, the independent rigid foil includes an arc-shaped rigid bearing part and an elastic deformation pin part. After being subjected to external vibration excitation, the independent rigid foil has good deformation space. The shape of the foil ring deforms rapidly following the transfer of the central rotating shaft and the air film. The foil ring has good followability, ensuring that the air film can be evenly distributed along with the vibration of the shaft, and the foil ring is not prone to colliding with the rotating shaft.

[0014] Preferably, the number of independent rigid foils is five.

[0015] Preferably, the outer ball bearing seat, the inner air bearing seat and the extended coaxial seat are integrally formed structures, which improves the stability of the overall structure and ensures that the rotation speed of the motor rotor is synchronized with the roller.

[0016] The beneficial technical effects of the present invention are as follows: the rotation direction of the drive motor is opposite to the rotation direction of the roller, driving the inner bearing seat to rotate in the reverse direction, increasing the relative rotation speed of the roller during takeoff, enabling the roller in the foil ring to take off faster and at a lower rotation speed;

[0017] The high-speed roller rotates in the same direction as the low-speed rotating inner bearing seat, reducing the actual relative rotation speed of the rotating shaft, reducing the relative friction and heat generation between the rotating shaft and the inner bearing seat, reducing wear and tear, and improving the service life and quality of the overall product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 is a front view structure schematic diagram of the present invention;

[0020] Figure 3 is a side view structure schematic diagram of the present invention;

[0021] In the figure: outer bearing seat 1, ball 11, inner bearing seat 2, outer ball bearing seat 21, inner air bearing seat 22, extended coaxial seat 23, foil ring 3, independent rigid foil 31, arc-shaped rigid bearing part 311, elastic deformation pin part 312, roller 4, drive motor 5, motor rotating shaft 51, motor stator 52. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be further described below with reference to the accompanying drawings. Through the description of the embodiments below, it will be more helpful for the public to understand the present invention. However, the specific embodiments given by the applicant should not be regarded as a limitation to the technical solution of the present invention. Any change in the definition of components or technical features or any formal but not substantial transformation of the overall structure should be regarded as the protection scope defined by the technical solution of the present invention. Embodiment

[0023] As Figure 1 shown: A kind of active shaft-type combined air bearing includes an outer bearing seat 1, an inner bearing seat 2, a roller 4 and a plurality of balls 11. Each ball is located between the outer bearing seat and the outer ball bearing seat 21. A foil ring 3 is provided on the inner wall of the inner air bearing seat 22, and the roller 4 is located within the foil ring 3.

[0024] As Figure 2As shown in the figure: The inner bearing housing 2 includes an outer ball bearing housing 21, an inner air bearing housing 22, and an extended coaxial housing 23. The outer ball bearing housing 21, the inner air bearing housing 22, and the extended coaxial housing 23 are of an integrally formed structure. The foil ring 3 is composed of five independent rigid foils 31 connected end to end in sequence. The independent rigid foil 31 includes an arc-shaped rigid bearing portion 311 and an elastic deformation pin portion 312. After the independent rigid foil is subjected to external vibration, it has a good deformation space. The shape of the foil ring deforms rapidly following the transfer of the central rotating shaft and the air film. The foil ring has good followability, ensuring that the air film can be evenly distributed along with the vibration of the shaft, and the foil ring is not likely to collide with the rotating shaft.

[0025] As Figure 3 shown in the figure: The drive motor 5 includes a motor rotating shaft 51 and a motor stator 52. The extended coaxial housing 23 is connected to the motor rotating shaft 51, and a drive motor 5 is connected to one end of the extended coaxial housing 23.

[0026] In this embodiment, when the roller 4 starts to rotate, the drive motor 5 starts to rotate. However, the rotation direction of the drive motor 5 is opposite to the rotation direction of the roller 4. The motor rotating shaft 51 drives the inner bearing housing 2 to rotate in the reverse direction. At this time, the relative rotational speed between the roller 4 and the inner bearing housing 2 is the sum of their rotational speeds. In this way, the relative rotational speed for the roller to take off is relatively increased. The outer layer of the gas in the air film on the roller rotates following the inner air bearing housing under the action of two opposite forces, and the inner layer rotates following the roller. The relative flow rate of the gas becomes faster. (The air film flow needs to be specially designed to ensure that the air film can work stably and the energy consumption in the air film is controlled). The static pressure increases, enabling the roller 4 in the foil ring 3 to take off faster and at a lower rotational speed. When the rotational speed of the roller 4 gradually increases after takeoff, the motor rotating shaft 51 in the drive motor gradually decelerates and rotates in the reverse direction. That is, when the roller 4 rotates at a high speed, the motor rotating shaft 51 drives the inner bearing housing 2 and the roller 4 to rotate in the same direction. The roller 4 rotating at a medium to high speed rotates in the same direction as the inner bearing housing 2 rotating at a low speed, so as to reduce the relative rotational speed between the roller and the inner bearing housing. The original maximum rotational speed of the rotating shaft minus the rotational speed of the inner bearing housing rotating in the same direction is the actual relative rotational speed of the rotating shaft relative to the inner bearing housing. The original rotational speed of the roller relative to the ground remains unchanged, but the rotational speed relative to the inner bearing housing decreases, reducing the relative friction and heat generation between the rotating shaft and the inner bearing housing, reducing wear and tear, and improving the service life and quality of the overall product.

[0027] Of course, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention. However, these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. An active shaft-type combined air bearing, characterized in that: It includes an outer bearing housing (1), an inner bearing housing (2), a roller (4) and a number of ball bearings (11). The inner bearing housing (2) includes an outer ball bearing seat (21), an inner air shaft seat (22) and an extended coaxial seat (23). Each ball bearing is located between the outer bearing housing and the outer ball bearing seat (21). A foil ring (3) is provided on the inner wall of the inner air shaft seat (22). The roller (4) is located within the foil ring (3). One end of the extended coaxial seat (23) is connected to a drive motor (5). The drive motor (5) includes a motor rotating shaft (51) and a motor stator (52). The extended coaxial seat (23) is connected to the motor rotating shaft (51). During the start-up phase of the drive motor (5): the rotation direction of the motor rotating shaft is opposite to the rotation direction of the roller (4). After the roller takes off and stabilizes: the motor rotating shaft gradually decelerates and rotates in the reverse direction, which is the same as the rotation direction of the roller (4).

2. The active shaft-type combined air bearing according to claim 1, wherein The foil ring (3) is composed of at least three independent rigid foils (31) connected end to end in sequence.

3. The active shaft-type combined air bearing according to claim 2, wherein The independent rigid foil (31) includes an arc-shaped rigid bearing portion (311) and an elastic deformation pin portion (312).

4. The active shaft-type combined air bearing according to claim 2, characterized in that, The number of independent rigid foils (31) is five.

5. The active shaft-type combined air bearing according to claim 1, wherein: The outer ball bearing seat (21), the inner air shaft seat (22) and the extended coaxial seat (23) are of an integrally formed structure.

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