RU2237199C1 - Radial sliding bearing for rotors of high-power turbine-driven sets - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: enclosing angle of the self-adjusting segment is 95-105⁰. The bearing cylindrical bore is made in the longitudinal bore for receiving the segment throughout the width of the working side of the bottom semi-insert. The passages of the main lubricant supply is made at an angle no less than 15⁰ to the horizontal plane of the semi-insert in the direction of rotation of the shaft. The working side of the segment is additionally provided with pockets having inner cross passages for batched supply of high-pressure lubricant. The passages are arranged symmetrically over the faces of the segment at a distance no less than 8% of the width of the insert and at an angle no less than 14⁰ to its vertical axis.

EFFECT: enhanced reliability and efficiency of the bearing.

4 cl, 3 dwg

Description

The present invention relates to the field of mechanical engineering, specifically turbine engineering, in particular to the production of radial plain bearings for rotors of powerful turbine units and turbogenerators.

Known designs of radial plain bearings of the sleeve type containing the upper and lower half liners with spherical bearing surfaces and internal semi-ring channels for supplying lubricant located in the upper half liner. The lubricant from the channels enters a horizontal recess against the direction of rotation of the shaft (Vishnivetsky MG, Mishchenko Yu.I. Improving radial bearings of turbines. NII INFORMTYAZHMASH, 1975, p. 10 and 11).

The reasons that impede the achievement of the technical result indicated below when using known devices include the fact that in the known devices, the contact of the spherical bearing surfaces of the liner and the bearing housing is made to fit with a slight interference fit and, accordingly, it does not allow the liner to move in the longitudinal direction, as a result of which it is not achieved at all reduction of the temperature and vibration level of the liner in nominal mode, especially with thermal shafts and Renos supports the turbine unit.

Known designs for radial segment bearings of the segment type containing upper and lower half-shells with moving segments supported by a swing rib or with a spherical (point) bearing of segments (Vishnivetsky MG, Mishchenko Yu.I. Improving radial bearings of turbines. NII INFORMTYAZHMASH, 1975 g., p. 23).

However, when using the known device in practice, due to increased contact stresses immediately in the place of abutment (segment - liner body), significant wrinkling of the contact surfaces and, accordingly, a significant limitation of the mobility of the bearing segments, a decrease in their bearing capacity and vibration reliability of the bearing under all possible operating modes of turbomachines are formed.

The closest device of a similar purpose to the proposed design for the totality of features and selected as a prototype is a radial sliding bearing device containing upper and lower half-liners, in the lower of which there is a support element mounted in the longitudinal direction, made in the form of a segment with a length in the circumferential direction of 70- 90 ° and leaning on a swing rib. Lubrication in the bearing is carried out through a channel in the lower half-liner at a horizontal plane in the direction of rotation of the shaft, while an eccentric bore is made in the area where it exits to the working surface. (RF patent No. 2079739, F 16 C 17/03 from 1.02.94, publ. B.I. No. 14, 1997)

The reasons that impede the achievement of the technical result indicated below when using the known device adopted for the prototype include the fact that due to increased contact stresses directly in the place of support along the rocking rib (bearing movable segment - liner body), a continuous, longitudinal, annular groove is directly formed on the supporting contact surface of the liner, due to its insufficient hardness and strength and, accordingly, the mobility of the bearing segment is sharply limited a, leading to its jamming. As a result, the bearing capacity of the bearing is reduced, which contributes to the occurrence of low-frequency vibration and a decrease in the reliability of the turbine unit, especially with thermal alignment of the shaft shaft and distortions of its bearings. With inaccurate manufacture or installation of a bearing segment of a known design, uneven moments of forces at its ends from the current load may occur, which leads to a violation of the stability of the position of the segment relative to the shaft, to a decrease in the bearing capacity and reliability of the bearing. Moreover, the lack of the possibility of additional drainage of the lubricant, as well as the rational organization of its supply, especially in the case of its operation at high specific loads, does not allow for the optimal temperature level, sufficient bearing capacity and operational reliability.

The desired technical result is to ensure the optimum temperature level of the working surface of the liner, increasing the reliability and efficiency of the bearing in all modes of operation, which causes the complex to increase the efficiency and reliability of the turbine unit as a whole.

The specified technical result in the implementation of the proposed technical solution is achieved by the fact that in the radial sliding bearing of the rotors of powerful turbine units containing the upper and lower half-liners, the lower of which has a longitudinally mounted support element-segment with a circumferential length of 70-90 ° and based on a swing rib, while containing a lubricant supply channel located at a horizontal plane in the direction of rotation of the shaft, and an eccentric bore, the self-aligning segment laid in the exit zone of the channel supplying lubricant to the working surface is made with a circumferential angle of coverage of 95-105 °, while the supporting cylindrical bore is made in a longitudinal groove for installing the segment along the entire width of the working surface of the lower half-liner, and the channels the main supply of lubricant is performed at an angle of not less than 15 ° to the horizontal plane of the half-liner in the direction of rotation of the shaft, and on the working surface of the lower half-liner is carried out communicated with the channels The drive has a profiled cavity in the form of a bore of rectangular cross section with a depth of at least 2.5 mm and a width of at least 65% of the width of the working surface of the lower liner, while on the working surface of the segment, pockets with internal cross channels for metered supply of high-pressure lubricant and located symmetrically at the ends of the segment at a distance of at least 8% of the liner width, and made at an angle of at least 14 to its vertical axis, the lower half of the bearing with they come in with a profiled cavity for additional lubricant drainage, which is placed along the entire width of the lower half-liner and at an angle of at least 40 ° to the horizontal plane against the direction of rotation of the shaft and having a rectangular profile with a depth of at least 2 mm, and directly in the specified bore and at a distance of not less than 10% of the liner width, additional radial channels symmetrically perform from its ends, which are positioned at an angle of not more than 42 ° to the horizontal plane against the direction of rotation of the shaft, and to half the liner from both ends of the working surface perform radial bevels with a length of at least 25% of the width of the liner and located at an angle of at least 2 ° to its working surface.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, as well as the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a technical solution characterized by signs identical or equivalent to those proposed.

The determination from the list of identified analogues of the prototype as the closest technical solution for the totality of features made it possible to identify in the claimed device a combination of significant distinguishing features in relation to the technical result perceived by the applicant and set forth in the following claims.

Therefore, the claimed invention meets the criteria of patentability of the invention of "novelty."

To verify the conformity of the proposed technical solution with the patentability criterion of the invention "inventive step", the applicant conducted an additional search using information known from the prior art. The search results showed that the invention does not follow from the prior art in a manner that is explicit for the skilled person. In particular, the invention does not provide for the following:

- addition of a known product by any known part (s) attached to it (by) according to known rules, in order to achieve a technical result in respect of which the effect of such additions is established;

- replacement of any part (s) of a known product with another known part to achieve a technical result, in respect of which the influence of such a replacement is established;

- the exclusion of any part (element) of the device with the simultaneous exclusion due to its function and the achievement of the well-known from the prior art for such an exception, etc .;

- an increase in the number of elements of the same type to enhance the technical result due to the presence in the tool of just such elements;

- the creation of a device consisting of known parts, the choice of which and the relationship between them, are based on known rules, recommendations, and the technical result achieved in this case is due only to the known properties of the parts of this tool and the connections between them.

Moreover, to achieve the desired result, the applicant introduced fundamental and non-obvious design changes into the half-shells of the radial plain bearing of the turbine rotor, and also provided him with new elements and connections. As a result, in the practical implementation of the proposed device, firstly, due to the implementation of the supporting surfaces of the self-aligning segment in the longitudinal direction as cylindrical with a reduced level of contact stresses and the simultaneous organization of an additional metered supply of high pressure lubricant through internal cross channels to the supporting surface of the liner, optimal conditions are created for ensuring uniformity and improvement of thermal conditions and reliability of the bearing at nominal specific and increased specific loads, as well as auto-installation of the bearing segment relative to the turbine unit shafting, which together increases the reliability and maintenance-free period of operation of the turbine unit.

Secondly, by rationally organizing the supply and removal of spent lubricant in the lower and upper half-liners, the temperature of the lubricant supply remains unchanged from the nominal value, which is due to the exception of mixing the supplied and spent lubricant, the intensive removal of which is provided by cavity 14, channels 15, bevels 16 and milled cavities 18 (see figures 1, 2).

Thirdly, due to the implementation of radial bevels 16 in the upper half and the use of movable oil seals 17, free self-installation of the bearing segment relative to the shaft is additionally ensured at all maximum possible thermal misalignments and distortions of the shaft support of the turbine unit during operation.

Fourth, the implementation of the length of the bearing segment in the circumferential direction strictly in the range of 90-105 ° (angle of coverage) is due to the fact that in most radial bearings of turbine units of known design in the nominal operating mode, the developed hydrodynamic wedge region is insufficient and is 95-105 ° with a maximum pressure in the lubricant layer, equal to 5.0-8.0 MPa (depending on the magnitude of the load). Together with pockets and internal cross channels for the metered supply of high-pressure lubricant 10 in the bearing segment at a certain angle to the vertical axis of the liner in the direction of rotation of the shaft “ω” and symmetrically located at the ends of the segment at a certain distance, it provides all modes of operation of the bearing as a result optimal hydrodynamic wedge in the bearing segment through internal cross channels, constant selection and, accordingly, metered supply of high-quality lubricant pressure (5-8 MPa) to the supporting surface 6 of the cylindrical segment directly to the recesses 9. Said constructive change allows a significant improvement in the mobility of the segment due to receipt of high pressure lubrication and increase the damping properties of the bearing.

Thus, we can conclude that the device proposed by the applicant ensures the achievement of the obvious non-obvious technical result, and the claimed invention meets the patentability criterion of "inventive step".

In the drawings explaining the essence of the claimed technical solution, are presented: FIG. 1, which shows a longitudinal section along the plane B-B of the radial plain bearing, and also FIG. 2, which shows a transverse section of the radial plain bearing along the plane A-A.

The radial plain bearing consists of the upper 1 and lower half-shells 2, support pillows 3, the working surface 4, the bearing segment 5 with the supporting cylindrical surface 6 and the internal cross channels of the dosed supply of high-pressure lubricant 7 at a distance l _t of the liner width “l” coming from pockets 8 on the working surface 4 in the recess 9 of the cylindrical surface 6 of the lower half-liner 2, in which the main supply of lubricant through the channels 10 is also made at an angle α ₁ to the horizontal plane of the liner in the direction rotation of the shaft “ω”, and on the working surface 4 there is a profiled eccentric bore 11 of rectangular shape, connected with feed channels 10 and made on intersecting axes, with a depth of at least 2.5 mm and a width of at least 65% of the width of the working surface “ l ”insert.

The mobility of the bearing self-aligning in the longitudinal direction of the segment 5, made with a coverage angle α ₂ = 95-105 ° in the circumferential direction, is provided by the supporting cylindrical surface 6, the gaps C ₁ (between its end surfaces and the ends of the oil seal housing 12) and the radial gaps C ₂ cylindrical fingers 13 installed in the housing of detachable seals 12, designed to fix the bearing segment 5. The latter in the circumferential direction is practically stationary due to its installation in the longitudinal groove of the lower half Adyshev zero or minimum clearance therebetween.

In the lower half-liner 2, there is a rectangular shaped cavity 14 for additional grease removal, the beginning of which is determined by an angle α ₃ to the horizontal plane against the direction of rotation of the shaft “ω” and comprising no more than 45, with a depth of at least 2 mm over the entire width of the lower half-liner “l ”, While directly in the cavity at a distance of at least 25% of the liner“ l ”width from its ends, radial channels 15 are additionally symmetrically designed for additional grease removal, located at an angle of not more than α ₄ = 42 ° to horizontal plane against the direction of rotation of the shaft “ω”, and in the upper half-liner 1 from both ends of the working surface radial bevels 16 are also made for additional greasing, length not less than 25% of liner width “l” (length l ₃ ) and at an angle not less than α ₅ = 2 ° to the working surface.

In the case of the lower halves of the seals 12, equipped with movable oil seals 17, as well as the lower half-liner 2, symmetrical milled cavities 18 are made for draining the waste lubricant from the inter-seal space.

Radial plain bearing operates as follows.

Lubrication at a nominal pressure of 0.06-0.12 MPa enters through the hole in the support cushion 3, channels 10 and cavity 11 to the working surface 4 of the bearing segment 5. With the beginning of rotation of the shaft of the turbomachine and as its speed increases to the nominal value in guaranteed a gap between the shaft and the working surface forms a hydrodynamic wedge, which causes the ascent of the shaft on the lubricating layer, while the bearing capacity of the bearing segment and, accordingly, the bearing, is determined by the magnitude of the ascent of the shaft, its location relative to itelno bore in vertical and horizontal directions, the temperature level of operation at different loads in all possible modes of operation of turbomachinery.

The implementation of the channels for supplying lubricant at an angle of at least 15 ° to the horizontal plane in the direction of rotation of the shaft “ω” provides an increased feed rate, optimizes the conditions of entry and distribution of lubricant on the working surface of the bearing segment and, accordingly, helps increase its bearing capacity.

Fresh lubricant enters from the channels 10 into the profiled cavity 11 of a rectangular profile, while the location of the cavity at an angle α ₁ = 30-32 ° on the cross axes with the supply channels 10 prevents the irregular flow of the supplied lubricant into the upper half-liner and improves the conditions for the lubricant to enter the working surface of the carrier segment.

Under conditions of skewed liner bearings or thermal misalignment of the turbine shaft shafts, respectively, at the ends of the working surface of a radial bearing, the pressure and clearances in the lubricant layer differ significantly in absolute value. The implementation of a longitudinally movable bearing segment already allows for its minimal self-installation and reduction of contact stress due to the use of a supporting cylindrical surface in it, and the organization of internal cross channels for the dosed supply of high-pressure lubricant additionally improves the self-alignment of the bearing segment relative to the shaft due to the automatic receipt of higher pressure on the opposite side of the supporting cylindrical surface of the liner, which ensures It increases the momentum of its rotation, and also helps to increase vibrational reliability due to the complete elimination of distortions on the working surface and the possibility of low-frequency shaft vibration, which generally increases the damping properties and vibrational reliability of the bearing.

In the lower half-liner at the exit from the carrier layer of the hydrodynamic wedge in the zone of angle α ₃ , a region of negative pressures is formed. In order to reduce the grease suction and its transfer to the upper half-liner 1, a cavity 14 and channels 15 are made in this area, through which part of the hot spent grease is discharged directly into the housing of the bearing housing.

The remaining small amount of hot spent grease is transferred to the working surface of the upper half-liner 1. Due to the presence of radial end bevels 16, located at an angle α ₅ to it and with a length of l ₃ , the spent grease is discharged directly into the inter-sealing space and then through the milled cavities 18 in the housing the lower halves of the seals 12 of the lower half-liner 2 is sent to the housing of the bearing housing.

Due to the practical presence of distortions of the supports and thermal misalignment of the shaft of turbine units that constantly occur during their operation, the unevenness of specific loads at the ends of the working surface of the lower half-liners increases, which leads to intensive wear, an increase in the temperature and vibration level due to a decrease in the bearing capacity of the bearings. For the proposed design, all structural arguments are valid at all possible specific loads due to the large reserve for its bearing capacity and vibrational reliability in all operating modes of turbine units.

Thus, the above information indicates that when using the proposed device the following set of conditions:

- a tool that embodies the proposed technical solution in its implementation, is used in the production of pillow block bearings for rotors of powerful turbine units and turbogenerators;

- for the claimed device in the form described in the independent clause of the patent formula for the invention set forth below, the possibility of its implementation using the means and methods known in the application description or known prior to the priority date is confirmed;

- a tool embodying the claimed invention in its implementation is capable of achieving the technical result perceived by the applicant, namely, it provides automatic installation of the bearing bearing segment in the longitudinal direction relative to the shaft shaft at all possible operating modes of turbomachines, which helps to increase vibration reliability and reduce temperature unevenness on the working surface of the bearing at nominal and increased specific loads, which contributes to increased reliability and repair ntoprigodnosti bearing, reduce wear and friction, lubrication and flow respectively increase turbine efficiency by reducing power losses due to friction and increase reliability.

Claims (5)

1. The radial sliding bearing of the rotors of powerful turbine units, containing the upper and lower half-liners, in the lower of which a support element is mounted that is self-aligning in the longitudinal direction, supported by a swing rib and made in the form of a segment, with a coverage angle in the circumferential direction of 70-90 °, and a lubricant supply channel located in an area close to the plane of the bearing connector, and an eccentric bore located in the exit zone of the channel supplying lubricant to the working surface, characterized in that The self-aligning segments are cylindrical in the longitudinal direction, with a reduced level of contact stresses, and the angle of coverage of the segment in the circumferential direction is 95-105 °, while the supporting cylindrical bore is made in the longitudinal groove to install the segment along the entire width of the working surface of the lower half-liner, and the channels the main lubricant supply is performed at an angle of at least 15 ° to the horizontal plane of the lower half-liner in the direction of rotation of the shaft, while on its working surface, at the repenting axes, additionally perform a profiled cavity, which is an eccentric bore of rectangular cross section and communicated with the lubricant supply channels, as well as an additional profiled cavity for drainage of grease, which is arranged at an angle of not more than 45 ° to the horizontal plane against the direction of rotation of the shaft and across the entire working width the surface of the lower half-liner, and directly in the said cavity and at a distance of at least 10% of the width of the liner from its ends, symmetrically perform for additionally radial channels disposed at an angle of not more than 42 ° to the horizontal plane against the direction of shaft rotation, and in the upper semiloose leaves from both ends of its working surfaces operate at an angle to the working surface of the radial chamfers. 2. The radial sliding bearing of the rotors according to claim 1, characterized in that the profiled cavity made on the working surface of the lower half-liner in the form of an eccentric bore of rectangular cross section has a depth of at least 2.5 mm and a width of at least 65% of the working width the surface of the lower half liner. 3. The radial sliding bearing of the rotors according to claim 1, characterized in that the additional profiled cavity for removing grease has a rectangular profile and is made with a depth of at least 2 mm 4. The radial sliding bearing of the rotors according to claim 1, characterized in that the radial bevels in the upper half-liner are made with a length of at least 25% of the width of the working surface of the liner, and are positioned at an angle of at least 2 ° to its working surface. 5. The radial sliding bearing of the rotors according to claim 1, characterized in that on the working surface of the self-aligning segment, pockets are additionally provided with internal cross channels for the metered supply of high-pressure lubricant and which are arranged symmetrically at the ends of the segment at a distance of at least 8% of the width liner, and at an angle of at least 14 ° to its vertical axis.

Images