Self-aligning pitch bearing

Abstract

The present invention belongs to the technical field of bearing equipment manufacturing, and particularly relates to a self-aligning pitch bearing, which includes a first outer ring, a second outer ring, an inner ring and rollers. An annular boss is provided on the outer diameter of the inner ring. The first outer ring and the second outer ring are respectively arranged on both sides of the annular boss. The two side surfaces of the annular boss form a first raceway and a second raceway. Two rows of tapered rollers are respectively installed in the first raceway and the second raceway. The outer circular surface of the annular boss forms a third raceway, and the self-aligning roller is installed in the third raceway. The pitch bearing of the present invention improves the problem of uneven load distribution while continuously increasing the bearing capacity of the bearing.

Description

Technical Field

[0001] The present invention belongs to the technical field of bearing equipment manufacturing, and particularly relates to a self-aligning pitch bearing. Background Art

[0002] In recent years, with the gradual recognition of clean energy by people, our understanding of wind power generation has become deeper and deeper, and the proportion of wind turbines has also become larger and larger. As a clean and renewable energy source, wind energy has attracted more and more attention from countries around the world. Wind power generation has developed rapidly globally and even become the main power source in some countries. With the continuous development of the wind power industry, small-power and small-megawatt wind turbines have gradually lost their competitive advantages, and domestic and foreign complete machine manufacturing enterprises are eager to develop large-power and large-impeller-diameter wind turbines of 3.0 MW and above.

[0003] The pitch bearing is an indispensable key component in the design of the entire wind turbine. It simultaneously bears the influence of axial load, radial load and overturning moment during operation, and has characteristics such as complex working load conditions, poor working conditions and relatively low overall stiffness. Therefore, the strength of the pitch bearing not only affects the overall life of the bearing, but also has an important impact on the overall stability and efficient and safe operation of the wind turbine generator set. Traditional pitch bearings are prone to eccentric loading, resulting in uneven load distribution on the entire raceway of the bearing and causing problems such as premature failure. Summary of the Invention

[0004] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a bearing with high load-bearing capacity and compact structure, which is mainly applied to the pitch bearing of large-megawatt and large-blade wind turbine generator sets to solve the problem of uneven load distribution during the operation of traditional three-row cylindrical roller pitch bearings.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a self-aligning pitch bearing, including a first outer ring, a second outer ring, an inner ring and rollers. An annular boss is provided on the outer diameter of the inner ring. The first outer ring and the second outer ring are respectively arranged on both sides of the annular boss. The two side surfaces of the annular boss form a first raceway and a second raceway. Two rows of tapered rollers are respectively installed in the first raceway and the second raceway. The outer cylindrical surface of the annular boss forms a third raceway, and a spherical roller is installed in the third raceway.

[0006] Further, the two rows of tapered rollers are axial tapered rollers for bearing axial loads.

[0007] Further, the spherical roller is a radial spherical roller for bearing radial loads, and the third raceway is an arc-shaped raceway.

[0008] Further, the third raceway is arranged in the middle of the outer cylindrical surface of the annular boss.

[0009] Further, the first outer ring and the second outer ring are positioned by cooperating with a frustum of a cone, and together form the outer ring of the pitch bearing.

[0010] Further, the large end sides of the two rows of tapered roller are close to the end with larger roller contact stress.

[0011] Further, the inner ring or the outer ring of the pitch bearing is connected to the blade structure, and the large end sides of the two rows of tapered roller are close to the blade structure.

[0012] Further, the first raceway and the second raceway are of unequal length structures.

[0013] Further, both sides of the pitch bearing are connected to the hub structure through the inner ring or the outer ring, and the axial raceway close to the hub side is longer than the axial raceway on the other side.

[0014] Further, a sealing ring is arranged between the first outer ring and the inner ring, and a sealing ring is arranged between the second outer ring and the inner ring.

[0015] The beneficial effects of the present invention are as follows: the pitch bearing of the present invention improves the problem of uneven load distribution while continuously increasing the bearing capacity of the bearing. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of a pitch bearing;

[0017] Figure 2 is an enlarged view of an axial tapered roller;

[0018] Figure 3 is an enlarged view of a radial self-aligning roller;

[0019] Figure 4 is the contact stress under the maximum contact force of the roller on the blade side;

[0020] Figure 5 is the contact stress under the maximum contact force of the roller on the hub side;

[0021] In the figure: 1. First outer ring, 2. Second outer ring, 3. Inner ring, 4. Axial tapered roller, 5. Radial self-aligning roller, 6. Sealing ring. Detailed Embodiments

[0022] In order to make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

[0023] See the appendix Figures 1 - 3, The self-aligning pitch bearing includes a first outer ring 1, a second outer ring 2, an inner ring 3 and rollers. The outer diameter of the inner ring 3 is provided with an annular boss. The first outer ring 1 and the second outer ring 2 are respectively arranged on both sides of the annular boss. Two side surfaces of the annular boss form a first raceway and a second raceway. Two rows of tapered rollers 4 are respectively installed in the first raceway and the second raceway. The two rows of tapered rollers are axial tapered rollers for bearing axial loads; the outer circumferential surface of the annular boss forms a third raceway. The third raceway is an arc-shaped raceway. The self-aligning roller 5 is installed in the third raceway. The self-aligning roller is a radial self-aligning roller for bearing radial loads.

[0024] Further, the third raceway is arranged in the middle of the outer circumferential surface of the annular boss, which is convenient for balancing the force.

[0025] Further, the first outer ring 1 and the second outer ring 2 are positioned by trapezoidal platform cooperation to jointly form the outer ring of the pitch bearing.

[0026] Further, the inner ring 3 or the outer ring of the pitch bearing is connected to the blade structure, and the other side is connected to the hub structure. The large end sides of the two rows of tapered rollers 4 are close to the blade structure. In this embodiment, Figures 1 - 3 Taking the inner ring connected to the blade structure and the outer ring side connected to the hub structure as an example, that is, the large end sides of the two rows of tapered rollers are close to the inner ring.

[0027] Further, the first raceway and the second raceway are of unequal length structure. The two sides of the pitch bearing are connected to the hub structure through the inner ring or the outer ring. The axial raceway close to the hub side is longer than the axial raceway on the other side.

[0028] Further, a sealing ring is arranged between the first outer ring 1 and the inner ring 3, and a sealing ring 6 is arranged between the second outer ring 2 and the inner ring 3.

[0029] Next, the structure and advantages of the pitch bearing of the present invention will be analyzed and described in combination with specific data.

[0030] 1) Change the structure of the traditional four-point contact ball of the pitch bearing to a three-row cylindrical roller structure, two rows of axial rollers + one row of radial rollers. Compared with the structure of the traditional four-point contact ball, the same size can bear a greater load and be applied to larger models; for the same load, a bearing with a smaller size can be selected, which has a great advantage in cost.

[0031] 2) In the traditional three-row roller bearing, all three rows of rollers are of cylindrical roller structure. This structure has a high load-bearing capacity, but during the operation of the bearing, it is easy to have eccentric loading, resulting in uneven load distribution on the entire raceway of the bearing and causing premature failure. Taking the finite element calculation results of the three-row cylindrical roller pitch bearing of a certain model as an example, the contact stress distribution results of the two rows of axial raceways are shown in Figure 4 and Figure 5 .

[0032] In order to improve this phenomenon, the following adjustments were made:

[0033] a. The three-row roller structure is retained, but the two rows of axial rollers are set as tapered roller structures and the radial rollers are set as spherical roller structures.

[0034] Based on the current limited analysis results, for the two rows of axial raceways, the large end of the tapered roller is set at the end where the contact stress is relatively large, and the small end is placed on the other side, so as to improve the problem of uneven stress distribution, achieve stress matching over the entire raceway length, and improve the strength and life of the entire raceway.

[0035] In the three-row roller bearing structure, compared with the size and complexity of the load-bearing of the two axial rows of rollers, the radial rollers are subjected to relatively small forces. The rollers in this position are set as a self-aligning structure, which can automatically align when the bearing is unbalanced during operation, and always maintain the optimal state to bear the load.

[0036] b. The commonly used connection forms of variable pitch bearings are analyzed, including the inner ring connected blade structure and the outer ring connected blade structure. The common trend is to place the large end of the roller close to the blade side and the small end of the roller away from the blade side.

[0037] c. Based on the analysis results of item b, the two rows of axial raceways are designed to be of unequal length, which can improve the strength of the cantilever beam and avoid raceway root cutting under heavy loads. The length of the two axial raceways is determined according to the stress distribution of the two raceways. The current structure is that the rolling element close to the hub side is longer, which can make the stress distribution of the two rows of raceways more uniform and improve the overall safety margin of the bearing.

[0038] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. Self-aligning pitch bearing, characterized in that: It includes a first outer ring, a second outer ring, an inner ring and rollers. An annular boss is provided on the outer diameter of the inner ring. The first outer ring and the second outer ring are respectively arranged on both sides of the annular boss. Two first raceways and second raceways are formed on two side surfaces of the annular boss. Two rows of tapered rollers are respectively installed in the first raceway and the second raceway. A third raceway is formed on the outer circular surface of the annular boss. A spherical roller is installed in the third raceway; the two rows of tapered rollers are axial tapered rollers for bearing axial loads; the spherical roller is a radial spherical roller for bearing radial loads, and the third raceway is an arc-shaped raceway; the large end sides of the two rows of tapered rollers are close to the end with larger roller contact stress; the inner ring or the outer ring of the pitch bearing is connected to the blade structure, and the large end sides of the two rows of tapered rollers are close to the blade structure; the first raceway and the second raceway are of unequal length structures; both sides of the pitch bearing are connected to the hub structure through the inner ring or the outer ring, and the axial raceway close to the hub side is longer than the axial raceway on the other side.

2. The self-aligning pitch bearing according to claim 1, wherein: The third raceway is arranged in the middle of the outer circular surface of the annular boss.

3. The self-aligning pitch bearing according to claim 1, characterized in that: The first outer ring and the second outer ring are positioned by trapezoidal platform cooperation to jointly form the outer ring of the pitch bearing.

4. The self-aligning pitch bearing according to claim 1, wherein: A sealing ring is arranged between the first outer ring and the inner ring, and a sealing ring is arranged between the second outer ring and the inner ring.

Images