CN103216571A - Permanent magnet bearing squeeze oil film damper - Google Patents

Abstract

The invention discloses a squeeze oil film damper for a permanent magnetic bearing, which comprises an oil film journal, a bearing outer ring, a bearing inner ring fixedly fitted on a shaft system, a lubricating oil cavity filled with lubricating oil, a bearing outer ring and an oil film shaft The necks are all located in the lubricating oil chamber, and the outer ring of the bearing is fixedly installed on the inner side of the oil film journal. It also includes an elastic mouse cage. One end of the elastic mouse cage is located outside the lubricating oil cavity and is fixed. The other end of the elastic mouse cage is connected to the The oil film journal is fixedly connected, the bearing inner ring and the bearing outer ring are both radially magnetized, and the opposite sides of the magnetized bearing inner ring and bearing outer ring are the same magnetic poles, and the bearing inner ring and the bearing outer ring There is an air gap in between. The invention can improve the damping capacity of the damper and its radial support rigidity.

Description

Permanent Magnetic Bearing Squeeze Film Damper

technical field

The invention relates to a squeeze oil film damper for a permanent magnetic bearing, which belongs to the technical field of non-contact bearing dampers.

Background technique

At present, in order to ensure the safe and stable operation of the shaft system, in various high-speed vertical rotating machines such as centrifuges, turbines, and energy storage flywheels, the suspended squeeze oil film damper shown in Figure 1 is often used at the upper end of the rotor Dampen the system. However, this kind of damper has two disadvantages: 1) The radial stiffness it can provide is too small and the anti-overturning ability is poor, resulting in too large inclination angle of the flywheel shafting during operation, and it is easy to cause the motor magnetic field to change drastically along the axial direction. Cause low-frequency precession; 2) The damping provided is too small. When the system experiences low-frequency motion, it cannot dissipate the excess energy of the shafting. Therefore, the damper that can provide greater radial stiffness and damping capacity will have important industrial application value.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a permanent magnetic bearing extrusion oil film damper, which can improve the damping capacity and radial support rigidity of the damper.

The technical solution adopted by the present invention to solve the above technical problems is: a permanent magnet bearing squeeze oil film damper, including an oil film journal, a bearing outer ring, a bearing inner ring fixedly fitted on the shafting, and a lubricating oil chamber filled with lubricating oil The body, bearing outer ring and oil film journal are all located in the lubricating oil chamber, and the bearing outer ring is fixedly installed on the inner side of the oil film journal, and also includes elastic squirrel cage bars, one end of the elastic squirrel cage bars is located outside the lubricating oil chamber and fixed, The other end of the elastic squirrel cage bar is fixedly connected to the oil film journal, the bearing inner ring and the bearing outer ring are both radially magnetized, and the opposite sides of the magnetized bearing inner ring and bearing outer ring are magnetic poles of the same sex, There is an air gap between the bearing inner ring and the bearing outer ring.

Further, the bearing inner ring is surrounded by a plurality of inner ring pieces.

Further, one side of the inner ring of the bearing is provided with a rubbing protection sleeve installed coaxially, and the diameter of the rubbing protection sleeve is slightly larger than that of the inner ring of the bearing.

Further, the elastic squirrel cage bars are made of stainless steel.

Further, the oil film journal is made of non-magnetic material.

Furthermore, the friction protection cover is made of bronze or polytetrafluoroethylene.

After adopting above-mentioned technical scheme, the present invention has following beneficial effect:

1. The permanent magnetic bearing composed of radially magnetized bearing inner ring and bearing outer ring not only has the function of automatic centering, but also can realize zero friction due to non-contact;

2. When the inclination angle of the shaft system is large, the elastic squirrel cage strips and the extruded oil film can provide sufficient radial stiffness for the shaft system together;

3. Relying on the repulsive force between the bearing inner ring and the bearing outer ring, the oil film journal is forced to move radially to squeeze the oil film, dissipating the excess energy generated by the system when the system is over critical or low frequency precession occurs;

4. The inner ring of the permanent magnetic bearing is composed of multiple ring pieces, which can greatly reduce the hoop tensile stress that the magnetic material bears when it rotates at high speed, so that it can work safely at a high speed;

5. The setting of the rubbing protection sleeve prevents the shafting from colliding and damaging the inner ring of the bearing when the radial displacement is too large during work.

Description of drawings

Fig. 1 is the structural representation of the suspension type squeeze oil film damper of prior art;

In Fig. 1, 9 is a soft magnetic ring; 10 is lubricating oil; 11 is a steel wire rope; 12 is a permanent magnetic ring;

Fig. 2 is the structural representation of permanent magnetic bearing squeeze oil film damper of the present invention;

Fig. 3 is a structural schematic diagram of the bearing inner ring of the present invention;

Fig. 4 is the top view of Fig. 3;

The arrows in Figure 1, Figure 2 and Figure 4 represent the magnetization direction.

Detailed ways

In order to make the content of the present invention more clearly understood, the present invention will be further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

As shown in Figures 2 to 4, a permanent magnetic bearing squeeze oil film damper includes an oil film journal 2, a bearing outer ring 3, a bearing inner ring 5 fixedly fitted on the shafting 4, and lubricating oil filled with lubricating oil 7 The cavity 8, the bearing outer ring 3 and the oil film journal 2 are all located in the lubricating oil cavity 8, and the bearing outer ring 3 is fixedly installed on the inner side of the oil film journal 2, and also includes elastic squirrel cage bars 1, elastic squirrel cage bars 1 The other end of the elastic squirrel cage bar 1 is fixedly connected with the oil film journal 2, the bearing inner ring 5 and the bearing outer ring 3 are radially magnetized, and the magnetized bearing inner ring The opposite sides of the ring 5 and the bearing outer ring 3 are magnetic poles of the same sex, and there is an air gap between the bearing inner ring 5 and the bearing outer ring 3 .

Bearing inner ring 5 and bearing outer ring 3, the opposite side of both is N pole or S pole.

In order to greatly reduce the hoop tensile stress that the magnetic material bears when it rotates at high speed, so that it can work safely at a high speed, as shown in Figures 3 and 4, the bearing inner ring 5 is composed of a plurality of inner ring pieces 5-1 surrounded. The number of inner ring pieces 5-1 in FIG. 4 is eight, but not limited thereto, and they can be bonded to the shafting 4 with epoxy resin.

In order to prevent the shafting 4 from colliding and damaging the bearing inner ring 5 when the radial displacement is too large during operation, as shown in Figure 2, one side of the bearing inner ring 5 is provided with a rubbing protection sleeve installed with the shafting 4 6. The diameter of the friction protection sleeve 6 is slightly larger than the diameter of the bearing inner ring 5 . The rubbing protection cover 6 can be made of bronze or polytetrafluoroethylene material, but not limited to these materials.

Both the bearing outer ring 3 and the bearing inner ring 5 are made of NdFeB magnetic material. The grade is N40, but is not limited to this material.

The elastic squirrel cage bar 1 is made of stainless steel, the grade is 1Cr18Ni9Ti, but not limited to this material.

The oil film journal 2 is made of magnetic-absolute material, such as duralumin, grade 2A13 or stainless steel, grade 1Cr18Ni9Ti, but not limited to these materials.

The working principle of the present invention is as follows:

When working, the elastic squirrel cage bar 1 and the squeezed oil film together provide the radial support stiffness for the shafting 4; relying on the repulsion between the bearing inner ring 5 and the bearing outer ring 3, the oil film journal 2 is forced to move to squeeze the oil film, To achieve the purpose of dissipating energy.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A permanent magnetic bearing squeeze oil film damper, including oil film journal (2), bearing outer ring (3) and bearing inner ring (5) fixedly set on the shafting (4) and filled with lubricating oil (7 ), the lubricating oil chamber (8), the bearing outer ring (3) and the oil film journal (2) are all located in the lubricating oil chamber (8), and the bearing outer ring (3) is fixedly installed on the oil film journal (2) It is characterized in that: it also includes an elastic squirrel cage (1), one end of the elastic squirrel cage (1) is located outside the lubricating oil cavity (8) and fixed, and the other end of the elastic squirrel cage (1) is in contact with the oil film The journal (2) is fixedly connected, the bearing inner ring (5) and the bearing outer ring (3) are radially magnetized, and the magnetized bearing inner ring (5) and the bearing outer ring (3) are relatively One side is the magnetic pole of the same sex, and there is an air gap between the bearing inner ring (5) and the bearing outer ring (3). 2. The permanent magnetic bearing squeeze oil film damper according to claim 1, characterized in that: the bearing inner ring (5) is surrounded by a plurality of inner ring pieces (5-1). 3. The squeeze oil film damper for permanent magnetic bearings according to claim 1, characterized in that: one side of the bearing inner ring (5) is provided with a rubbing protection sleeve (6) installed on the coaxial system (4), The diameter of this friction protection sleeve (6) is slightly larger than the diameter of the bearing inner ring (5). 4. The permanent magnetic bearing squeeze oil film damper according to claim 1, characterized in that: the elastic squirrel cage (1) is made of stainless steel. 5. The extruded oil film damper for permanent magnetic bearings according to claim 1, characterized in that: the oil film journal (2) is made of a magnetically insulating material. 6. The squeeze oil film damper for permanent magnetic bearings according to claim 1, characterized in that: the friction protection sleeve (6) is made of bronze or polytetrafluoroethylene.

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