Elliptical bearings for gas turbines

Abstract

The present invention provides an elliptical bearing for a gas turbine, comprising: an upper half bearing, wherein the center of a circle corresponding to a first inner arc surface of the upper half bearing is offset downwardly by a distance L1 relative to the center of the bearing along a vertical reference line, and the radius corresponding to the first inner arc surface is R1; a three-segment profile structure of a lower half bearing comprises a second inner arc surface and a third inner arc surface symmetrically distributed on both sides of the second inner arc surface, the center of a circle corresponding to the second inner arc surface coincides with the center of the bearing, the radius corresponding to the second inner arc surface is R2, the center angle corresponding to the second inner arc surface is α, the center of a circle corresponding to the third inner arc surface is offset upwardly by a distance L2 relative to the center of the bearing along a vertical reference line, and the radius corresponding to the third inner arc surface is R3. The present invention has better radial shock resistance, is more conducive to reducing the power consumption of the elliptical bearing, and enables the elliptical bearing to maintain a relatively low temperature state during high-speed operation of the journal.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to an elliptical bearing for a gas turbine. Background Art

[0002] The rotor bearing system is an important part of the gas turbine. The bearing is used to ensure that the rotor rotates on a fixed axis and bear the static and dynamic forces of the rotor. The radial bearing lifts the journal through the oil wedge at the bottom of the bearing, forming liquid friction between the journal and the bearing to bear the radial force of the rotor.

[0003] As the capacity of gas turbine generator sets continues to increase, the size of the rotor journal continues to increase, the linear speed increases, and the operating conditions of the bearings become increasingly severe. Conventional bearings can no longer meet the requirements of normal operation and are very prone to instability. The existing elliptical bearings include an upper half bearing and a lower half bearing. The inner circumferential wall of the upper half bearing and the inner circumferential wall of the lower half bearing are both composed of a circular arc surface. The journal rotates very unstable in conventional bearings. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the technical problem to be solved by the present invention is to provide an elliptical bearing for a gas turbine, which has better radial vibration resistance, is more conducive to reducing the power consumption of the elliptical bearing, and enables the elliptical bearing to maintain a lower temperature state during high-speed operation of the shaft neck.

[0005] In order to solve the above technical problems, the present invention provides an elliptical bearing for a gas turbine, the elliptical bearing having a bearing center, a horizontal reference line and a vertical reference line passing through the bearing center, and the elliptical bearing comprising:

[0006] The upper half of the bearing shell, the outer peripheral wall of the upper half of the bearing shell is a first outer arc surface, the center of the circle corresponding to the first outer arc surface coincides with the center of the bearing, the inner peripheral wall of the upper half of the bearing shell is a first inner arc surface, the center of the circle corresponding to the first inner arc surface is offset downward by a distance L1 relative to the center of the bearing along the vertical reference line, and the radius corresponding to the first inner arc surface is R1;

[0007] The lower half bearing shell, the outer peripheral wall of the lower half bearing shell is a second outer arc surface, the center of the circle corresponding to the second outer arc surface coincides with the center of the bearing, the inner peripheral wall of the lower half bearing shell presents a three-segment profile structure, the three-segment profile structure includes a second inner arc surface and a third inner arc surface symmetrically distributed on both sides of the second inner arc surface, the center of the circle corresponding to the second inner arc surface coincides with the center of the bearing, the radius corresponding to the second inner arc surface is R2, the center angle corresponding to the second inner arc surface is α, the center of the circle corresponding to the third inner arc surface is offset upward by a distance L2 relative to the center of the bearing along the vertical reference line, and the radius corresponding to the third inner arc surface is R3;

[0008] An oil groove structure, the oil groove structure is arranged at the middle dividing surface between the upper half bearing and the lower half bearing, the oil groove structure comprises an upper half oil groove opened in the upper half bearing and a lower half oil groove opened in the lower half bearing, the upper half oil groove is a fourth inner arc surface, the center of the circle corresponding to the fourth inner arc surface is offset downward by a distance L3 relative to the center of the bearing along the vertical reference line, the radius corresponding to the fourth inner arc surface is R4, and the center angle corresponding to the fourth inner arc surface relative to the center of the bearing is β, the lower half oil groove is a fifth inner arc surface, the center of the circle corresponding to the fifth inner arc surface is offset upward by a distance L4 relative to the center of the bearing along the vertical reference line, the radius corresponding to the fifth inner arc surface is R5, and the center angle corresponding to the fifth inner arc surface relative to the center of the bearing is δ;

[0009] R2<R1=R3, R4>R5, δ≤α≤180°-δ, L3>L1>L2, L3>L4>L2.

[0010] Preferably, the central angle δ>the central angle β.

[0011] As described above, the elliptical bearing for gas turbine of the present invention has the following beneficial effects: In the present invention, compared with the existing elliptical bearing, the outer circumferential wall of the upper half of the bearing and the outer circumferential wall of the lower half of the bearing are unchanged. Compared with the existing elliptical bearing, the inner circumferential wall of the upper half of the bearing and the inner circumferential wall of the lower half of the bearing are optimized as follows: the center of the circle corresponding to the first inner arc surface is offset downward by a distance L1 relative to the center of the bearing along the vertical reference line, the radius corresponding to the first inner arc surface is R1, the inner circumferential wall of the lower half of the bearing presents a three-section profile structure, the three-section profile structure includes a second inner arc surface and a third inner arc surface symmetrically distributed on both sides of the second inner arc surface, the center of the circle corresponding to the second inner arc surface coincides with the center of the bearing, the radius corresponding to the second inner arc surface is R2, the center angle corresponding to the second inner arc surface is α, and the center of the circle corresponding to the third inner arc surface is offset upward by a distance L1 relative to the center of the bearing along the vertical reference line. The distance between the bearing and the bearing is L2, and the radius corresponding to the third inner arc surface is R3, R2<R1=R3, L1>L2. With such a design, compared with the existing elliptical bearing, the top thickness of the upper half of the bearing becomes thicker, and the bottom thickness of the lower half of the bearing becomes thinner. In other words, the absolute eccentricity of the journal in the upper half of the bearing becomes smaller, and the absolute eccentricity of the journal in the lower half of the bearing becomes larger. The journal is more likely to press against the inner circumferential wall of the lower half of the bearing for rotation. In addition, since the lower half of the bearing is the main bearing part and the upper half of the bearing is basically not subjected to force during the rotation of the journal, on the whole, the journal in the elliptical bearing of the present invention has less vibration and rotates more smoothly. That is, the elliptical bearing for gas turbines has better radial seismic resistance. In addition, the oil groove structure is arranged at the middle dividing surface of the upper half bearing and the lower half bearing, and the oil groove structure includes an upper half oil groove opened in the upper half bearing and a lower half oil groove opened in the lower half bearing, the upper half oil groove is a fourth inner arc surface, the center of the circle corresponding to the fourth inner arc surface is offset downward by a distance L3 relative to the center of the bearing along the vertical reference line, the radius corresponding to the fourth inner arc surface is R4, and the center angle corresponding to the fourth inner arc surface relative to the center of the bearing is β, and the lower half oil groove is a fifth inner arc surface, and the center of the circle corresponding to the fifth inner arc surface is relative to The distance that the center of the bearing is offset upward along the vertical reference line is L4, the radius corresponding to the fifth inner arc surface is R5, and the central angle corresponding to the fifth inner arc surface relative to the center of the bearing is δ, R4>R5, L3>L1, L3>L4>L2. With this design, the oil inlet cross-section of the lower oil groove is larger than the oil inlet cross-section of the upper oil groove, so that more turbine oil enters the lower half of the bearing, thereby improving the heat dissipation efficiency and lubrication effect of the lower half of the bearing, and is more conducive to reducing the power consumption of the elliptical bearing, so that the elliptical bearing can maintain a low temperature state during high-speed operation of the shaft neck. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram showing an elliptical bearing for a gas turbine according to the present invention is shown.

[0013] Component number description

[0014] 1 Bearing center

[0015] 2 Horizontal reference line

[0016] 3 Vertical reference line

[0017] 4 Upper half bearing

[0018] 41 First outer arc surface

[0019] 42 First inner arc surface

[0020] 5. Lower half bearing

[0021] 51 Second outer arc surface

[0022] 52 Second inner arc surface

[0023] 53 The third inner arc surface

[0024] 6 Oil tank structure

[0025] 61 Fourth inner arc surface

[0026] 62 Fifth inner arc surface DETAILED DESCRIPTION

[0027] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0028] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0029] like Figure 1 As shown, the present invention provides an elliptical bearing for a gas turbine, the elliptical bearing having a bearing center 1, a horizontal reference line 2 and a vertical reference line 3 passing through the bearing center 1, and the elliptical bearing comprises:

[0030] The upper half bearing 4, the outer peripheral wall of the upper half bearing 4 is a first outer arc surface 41, the center of the circle corresponding to the first outer arc surface 41 coincides with the bearing center 1, the inner peripheral wall of the upper half bearing 4 is a first inner arc surface 42, the center of the circle corresponding to the first inner arc surface 42 is offset downward by a distance L1 relative to the bearing center 1 along the vertical reference line 3, and the radius corresponding to the first inner arc surface 42 is R1;

[0031] The lower half bearing shell 5, the outer peripheral wall of the lower half bearing shell 5 is a second outer arc surface 51, the center of the circle corresponding to the second outer arc surface 51 coincides with the bearing center 1, the inner peripheral wall of the lower half bearing shell 5 presents a three-segment profile structure, the three-segment profile structure includes a second inner arc surface 52 and a third inner arc surface 53 symmetrically distributed on both sides of the second inner arc surface 52, the center of the circle corresponding to the second inner arc surface 52 coincides with the bearing center 1, the radius corresponding to the second inner arc surface 52 is R2, the center angle corresponding to the second inner arc surface 52 is α, the center of the circle corresponding to the third inner arc surface 53 is offset upwardly by a distance L2 relative to the bearing center 1 along the vertical reference line 3, and the radius corresponding to the third inner arc surface 53 is R3;

[0032] The oil groove structure 6 is arranged at the middle dividing surface between the upper half bearing shell 4 and the lower half bearing shell 5. The oil groove structure 6 includes an upper half oil groove opened in the upper half bearing shell 4 and a lower half oil groove opened in the lower half bearing shell 5. The upper half oil groove is a fourth inner arc surface 61. The center of the circle corresponding to the fourth inner arc surface 61 is offset downward by a distance L3 relative to the bearing center 1 along the vertical reference line 3. The radius corresponding to the fourth inner arc surface 61 is R4. The center angle corresponding to the fourth inner arc surface 61 relative to the bearing center 1 is β. The lower half oil groove is a fifth inner arc surface 62. The center of the circle corresponding to the fifth inner arc surface 62 is offset upward by a distance L4 relative to the bearing center 1 along the vertical reference line 3. The radius corresponding to the fifth inner arc surface 62 is R5. The center angle corresponding to the fifth inner arc surface 62 relative to the bearing center 1 is δ.

[0033] R2<R1=R3, R4>R5, δ≤α≤180°-δ, L3>L1>L2, L3>L4>L2.

[0034] In the present invention, compared with the existing elliptical bearing, the outer circumferential wall of the upper half bearing 4 and the outer circumferential wall of the lower half bearing 5 do not change, that is, the outer circumferential wall of the upper half bearing 4 is a first outer arc surface 41, and the center of the circle corresponding to the first outer arc surface 41 coincides with the bearing center 1, and the outer circumferential wall of the lower half bearing 5 is a second outer arc surface 51, and the center of the circle corresponding to the second outer arc surface 51 coincides with the bearing center 1. Compared with the existing elliptical bearing, the inner circumferential wall of the upper half bearing 4 and the inner circumferential wall of the lower half bearing 5 are optimized as follows: the center of the circle corresponding to the first inner arc surface 42 is offset downward by a distance L1 relative to the bearing center 1 along the vertical reference line 3, the radius corresponding to the first inner arc surface 42 is R1, and the inner circumferential wall of the lower half bearing 5 presents a three-section profile structure, which includes a second inner arc surface 52 and a third inner arc surface 53 symmetrically distributed on both sides of the second inner arc surface 52, the center of the circle corresponding to the second inner arc surface 52 coincides with the bearing center 1, the radius corresponding to the second inner arc surface 52 is R2, the center angle corresponding to the second inner arc surface 52 is α, and the center of the circle corresponding to the third inner arc surface 53 is relative to the bearing center 1 along the vertical reference line 3. The upward offset distance of line 3 is L2, and the radius corresponding to the third inner arc surface 53 is R3, R2<R1=R3, L1>L2. With such a design, compared with the existing elliptical bearing, the top thickness of the upper half of the bearing 4 becomes thicker, and the bottom thickness of the lower half of the bearing 5 becomes thinner. In other words, the absolute eccentricity of the journal in the upper half of the bearing 4 becomes smaller, and the absolute eccentricity of the journal in the lower half of the bearing 5 becomes larger. The journal is more likely to press against the inner circumferential wall of the lower half of the bearing 5 for rotation. Since the lower half of the bearing 5 is the main bearing part during the rotation of the journal and the upper half of the bearing 4 is basically not subjected to force, on the whole, the journal vibrates less in the elliptical bearing of the present invention and rotates more smoothly, that is, the elliptical bearing for gas turbines has better radial seismic resistance.

[0035] In addition, the oil groove structure 6 is arranged at the middle dividing surface of the upper half bearing 4 and the lower half bearing 5. The oil groove structure 6 includes an upper half oil groove opened in the upper half bearing 4 and a lower half oil groove opened in the lower half bearing 5. The upper half oil groove is a fourth inner arc surface 61. The center of the circle corresponding to the fourth inner arc surface 61 is offset downward by a distance L3 relative to the bearing center 1 along the vertical reference line 3. The radius corresponding to the fourth inner arc surface 61 is R4. The center angle of the fourth inner arc surface 61 relative to the bearing center 1 is β. The lower half oil groove is a fifth inner arc surface 62. The center of the circle corresponding to the fifth inner arc surface 62 is offset downward by a distance L3 relative to the bearing center 1 along the vertical reference line 3. The radius corresponding to the fourth inner arc surface 61 is R4. The center angle of the circle corresponding to the fourth inner arc surface 61 relative to the bearing center 1 is β. The upward offset distance along the vertical reference line 3 is L4, the radius corresponding to the fifth inner arc surface 62 is R5, and the central angle corresponding to the fifth inner arc surface 62 relative to the bearing center 1 is δ, R4>R5, L3>L1, L3>L4>L2. With such a design, the oil inlet cross-section of the lower oil tank is larger than the oil inlet cross-section of the upper oil tank, so that more turbine oil (that is, turbine oil, which generally has high temperature resistance and wear resistance) enters the lower half of the bearing 5, thereby improving the heat dissipation efficiency and lubrication effect of the lower half of the bearing 5, and is more conducive to reducing the power consumption of the elliptical bearing, so that the elliptical bearing can maintain a low temperature state during high-speed operation of the shaft neck.

[0036] The aforementioned central angle δ>the aforementioned central angle β.

[0037] In summary, the elliptical bearing for gas turbine of the present invention has better radial vibration resistance, is more conducive to reducing the power consumption of the elliptical bearing, and enables the elliptical bearing to maintain a lower temperature state during high-speed operation of the journal. Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An elliptical bearing for a gas turbine, the elliptical bearing having a bearing center (1), a horizontal reference line (2) and a vertical reference line (3) passing through the bearing center (1), characterized in that: The elliptical bearing comprises: The upper half bearing shell (4) has an outer peripheral wall of a first outer arc surface (41), the center of a circle corresponding to the first outer arc surface (41) coincides with the center of the bearing (1), the inner peripheral wall of the upper half bearing shell (4) is a first inner arc surface (42), the center of a circle corresponding to the first inner arc surface (42) is offset downwardly by a distance L1 relative to the center of the bearing (1) along a vertical reference line (3), and the radius corresponding to the first inner arc surface (42) is R1; A lower half bearing shell (5), wherein the outer peripheral wall of the lower half bearing shell (5) is a second outer arc surface (51), the center of the circle corresponding to the second outer arc surface (51) coincides with the center of the bearing (1), the inner peripheral wall of the lower half bearing shell (5) presents a three-segment profile structure, the three-segment profile structure comprises a second inner arc surface (52) and a third inner arc surface (53) symmetrically distributed on both sides of the second inner arc surface (52), the center of the circle corresponding to the second inner arc surface (52) coincides with the center of the bearing (1), the radius corresponding to the second inner arc surface (52) is R2, the center angle corresponding to the second inner arc surface (52) is α, the center of the circle corresponding to the third inner arc surface (53) is offset upwards by a distance L2 relative to the center of the bearing (1) along the vertical reference line (3), and the radius corresponding to the third inner arc surface (53) is R3; The oil groove structure (6) is arranged at the middle dividing surface between the upper half bearing shell (4) and the lower half bearing shell (5), and the oil groove structure (6) includes an upper half oil groove opened in the upper half bearing shell (4) and a lower half oil groove opened in the lower half bearing shell (5), the upper half oil groove is a fourth inner arc surface (61), the center of the circle corresponding to the fourth inner arc surface (61) is offset downward by a distance L3 relative to the center of the bearing (1) along the vertical reference line (3), and the fourth inner arc surface (61) is 1) has a radius R4, a center angle β of the fourth inner arc surface (61) relative to the bearing center (1), the lower half oil groove is the fifth inner arc surface (62), the center of the circle corresponding to the fifth inner arc surface (62) is offset upward by a distance L4 from the bearing center (1) along the vertical reference line (3), the radius R5 of the fifth inner arc surface (62), and the center angle δ of the fifth inner arc surface (62) relative to the bearing center (1); R2<R1=R3, R4>R5, δ≤α≤180°-δ, L3>L1>L2, L3>L4>L2.

2. The elliptical bearing for a gas turbine according to claim 1, characterized in that: The central angle δ>the central angle β.

Images