RU2722107C1 - Reversible plain bearing (embodiments) - Google Patents

Abstract

FIELD: machine building.SUBSTANCE: invention relates to machine building, namely, to plain bearings with self-aligning shoes, and can be used as sliding supports for steam turbines, compressors, pumps and other rotary machines. Reversible sliding bearing includes housing with lubrication feed channels and drain cavity, shaft covered with self-aligning blocks, each of which has hydrostatic pockets on backs of shoe. On the working surface of the lower shoe there is additionally hydrostatic pockets of the lubricant, and in the bearing housing there is an additional hole for supply of lubricant to the hydrostatic pockets on the working surface of the lower shoe, wherein each of the hydrostatic pockets on the working surface of the lower shoe is connected to the additional opening in the bearing housing for supplying lubricant to the said hydrostatic pockets, wherein circumferential length and axial width of working surface of lower shoe is greater than circumferential length and axial width of working surface of any other shoe of bearing. Besides, in body of lower shoe under its working surface there are channels for additional cooling of lower shoe. In the second embodiment of the reversible sliding bearing, the back of each of the bearing blocks and the surface of the housing, which is conjugated with the back of the shoe, have a spherical shape.EFFECT: technical result is creation of reversible sliding bearing with high bearing and damping capacity both during start-up and shutdown, and at working frequencies of rotation at its use in rotor machines with heavy rotors.19 cl, 16 dwg

Description

The invention relates to the field of mechanical engineering, namely, sliding bearings with self-aligning blocks, and can be used as sliding bearings for steam turbines, compressors, pumps and other rotary machines.

A bearing assembly is known, comprising a housing with oil supply channels and a drain cavity, a shaft pin, self-aligning blocks covering a shaft pin, with radial holes made in the central part of the working surface and in the inlet and outlet edges of the distribution grooves, one of which, in the inlet edge, connected through channels in the body of the block to the oil supply channels, and the other, in the starting edge, is made through and parallel to the longitudinal axis of the bearing assembly, fixing screws, oil scraper, and an oil scraper is installed in the space between each block [UA No. 763, F16C 32/06, 2001].

Plain bearings with blocks equipped with a central pocket with a connecting radial bore are reversible and can work when the shaft rotates both clockwise and counterclockwise. Their disadvantage is the low bearing capacity, as well as the instability of operation due to the non-vertical trajectory of the shaft in the bearing.

Closest to the claimed invention is a reversible plain bearing, comprising a housing with oil supply channels and a drain cavity, a shaft surrounded by self-aligning blocks, each of which has a radial hole in the central part of its working surface and a hydrostatic pocket on the inner surface of the housing, one fixing screw with a spherical head, oil scraper tubes made of wear-resistant material installed in the interwell space, while at least one block has a second hydrostatic pocket and a second radial hole [UA No. 20524 U, F16C 32/06, 2007].

The disadvantage of this design is the limited bearing capacity, not optimal for heavy rotors. At the time of start-up, when the working surfaces of the self-aligning shoe and the shaft journal come into contact, they wear out, entailing an increase in the clearance in the bearing, to compensate for which it is necessary to increase the gaps between the rotor and the stator, which reduces the efficiency of the unit. During operation, an unacceptably high temperature of the carrier hydrodynamic film occurs.

The basis of the invention is the task of creating a reversible plain bearing with high bearing and damping ability both during start-up and shutdown, and at operating speeds when used in rotary machines with heavy rotors.

The problem is solved in that in a reversible plain bearing containing a housing with lubricant supply channels and a drain cavity, a shaft surrounded by self-aligning blocks, each of which has hydrostatic pockets on the backs of the block and radial holes connected to them located symmetrically relative to the center of the block, fixing screws with spherical heads, oil scraper installed in the inter-deck space, according to the invention, hydrostatic grease pockets are additionally made on the working surface of the lower block, and an additional hole is provided in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower block, each of which hydrostatic pockets on the working surface of the lower pads connected to an additional hole in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower pads through channels in the body of the lower pads.

Hydrostatic pockets on the working surface of the lower pads can be made in the form of holes and are located in its central part symmetrically with respect to the longitudinal and transverse axis of the lower pads.

To further increase the bearing and damping capacity of the bearing in the body of the lower block due to the presence of channels under its working surface, lubrication can be arranged for additional cooling of the lower block, and holes in the bearing housing are additionally provided for supplying lubricant to the channels for additional cooling of the lower block, this, these channels can be located either only in the rear, or in the rear and front parts of the lower block symmetrically relative to its longitudinal axis.

The circumferential extent (angle of coverage) and the axial width of the working surface of the lower block may be greater than the circumferential length and axial width of the working surface of any other bearing block, respectively.

In addition, pads with a smaller axial width of the working surface can be offset relative to the lower pads in one direction or in opposite directions along the axis of the bearing.

Moreover, each of the pads with a smaller axial width of the working surface can be provided with a groove with a depth of 0.5-1.5 mm or a depth corresponding to the thickness of the pad over the entire circumferential length of the working surface in its central part.

The problem is also solved by the fact that in a reversible plain bearing containing a housing with lubricant supply channels and a drain cavity, a shaft covered by self-aligning blocks, each of which has hydrostatic pockets on the backs of the block and radial holes connected to them, located symmetrically relative to the center of the block, fixing screws with spherical heads, oil scraper installed in the inter-deck space, according to the invention, the back of each of the bearing pads, the surface of the housing that mates with the back of the block, have a spherical shape.

Hydrostatic pockets of grease can be additionally made on the working surface of the lower block, and an additional hole is provided in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower block, each of the hydrostatic pockets on the working surface of the lower block being connected to an additional hole in the bearing housing for supplying lubricant to said hydrostatic pockets by means of channels in the body of the lower block.

Hydrostatic pockets on the working surface of the lower block can be located in its central part symmetrically with respect to the longitudinal and transverse axis of the lower block.

Hydrostatic pockets on the working surface of the lower pads can be made in the form of holes.

Channels for additional cooling of the lower block can be made in the body of the lower block under its working surface, and these channels are located either in the rear, or in the rear and front parts of the lower block symmetrically with respect to its longitudinal axis.

The circumferential length and axial width of the working surface of the lower block is greater than the circumferential length and axial width of the working surface of any other bearing block.

Pads with a smaller axial width of the working surface can be offset relative to the lower block in one direction along the axis of the bearing.

Pads with a smaller axial width of the working surface can be offset relative to the lower block in opposite directions along the axis of the bearing.

Each of the pads with a smaller axial width of the working surface can be provided with a groove 0.5-1.5 mm deep over the entire circumferential length of the working surface in the central part of the shoe.

Each of the blocks with a smaller axial width of the working surface can be provided with a groove with a depth corresponding to the thickness of the block over the entire circumferential length of the block in its central part.

The second option is advisable to use to compensate for the angular displacement of the axis of the neck of the shaft relative to the axis of the bearing and the subsequent uniform distribution of radial load over the entire working surface of the pads.

The above signs of the proposed technical solution are necessary and sufficient to achieve the technical task with the achievement of a qualitative new technical result.

A constructive solution in which on the working surface of the lower block in its central part symmetrically relative to the longitudinal and transverse axis of the lower block additionally in the form of holes are made hydrostatic grease pockets, and in the bearing housing there is an additional hole for supplying grease to the hydrostatic pockets mentioned above on the working surface of the lower pads, moreover, each of the hydrostatic pockets on the working surface of the lower pads is connected to an additional hole in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower pads through additional channels in the body of the lower pads, prevents contact of the pads and the shaft neck at the time of starting the rotary machine due to the supply of grease into these pockets under high pressure through additional holes, both in the block and in the bearing housing, which allows for hydraulic lifting of the shaft at low speeds. The location of the hydrostatic grease pockets on the working surface of the lower block is symmetrical with respect to its longitudinal and transverse axes, which implies the presence of a pair of them and provides a more stable hydraulic lift of the shaft at the time of start-up.

At the same time, in the body of the lower block in the rear and front parts symmetrically with respect to the longitudinal axis of the lower block, under its working surface there are lubricant supply channels for additional cooling of the block, and holes are provided in the bearing housing for supplying lubricant to the channels for additional cooling of the lower pads, allows you to create such a cooling system pads of the thrust bearing, in which due to the direction of part of the lubricating oil to lower the temperature of the working surface of the lower pads, conditions are created that enable the reverse bearing to absorb large radial loads compared to the prototype.

The execution of the circumferential length (angle of coverage) and the axial width of the working surface of the lower block is greater than the circumferential length and the axial width of the working surface of any other bearing block, helps to increase the damping ability of the lower block and provides the ability to place hydrostatic pockets that provide hydraulic lifting at the time of start-up.

To more effectively solve the problem of increasing the bearing capacity of a reversing bearing, the axial width of the working surface of the lower block is additionally larger than any other block. Reducing the axial width of any other pad other than the bottom improves cooling of the bottom pad by reducing the amount of “warm” grease flowing into the bottom pad, that is, into the pad with a larger axial width of the working surface, from the pad with a smaller axial width of the working surface. A reduced amount of “warm” grease is made up for by an additional amount of “cold” grease supplied to the inter-deck space, as a result of which a more “cold” oil enters the lower block.

In this case, one example of such an implementation of the claimed technical solution is achieved in that the pads with a smaller axial width of the working surface are offset relative to the lower pads in one direction along the axis of the bearing; another example is achieved in that the pads with a smaller axial width of the working surface are offset from the lower pads in opposite directions along the axis of the bearing; another example of the implementation of this technical solution is achieved in that each of the pads with a smaller axial width of the working surface is provided with a groove with a depth of 0.5-1.5 mm over the entire circumferential length of the working surface in the central part of the block; and another example of implementation is achieved in that each of the blocks with a smaller axial width of the working surface is provided with a groove with a depth corresponding to the thickness of the block over the entire circumferential length of the block in its central part.

The invention is illustrated by drawings.

In FIG. 1 shows a cross section of a reversing plain bearing with an enlarged angle of coverage of the lower block;

in FIG. 2 is a section along aa of FIG. 1;

in FIG. 3-section according to BB FIG. 14;

in FIG. 4 shows hydrostatic pockets in the bottom block providing hydraulic lift during start-up, and the oil supply to these pockets is shown schematically;

in FIG. 5 schematically shows the supply of oil to the channels for additional cooling pads;

in FIG. 6 - lower block with channels for additional cooling in its rear part;

in FIG. 7 - bottom block with channels for additional cooling in its rear and front;

in FIG. 8 shows the location of the bottom pads, namely, channels for additional cooling pads;

in FIG. 9 schematically shows the oil supply to the oil scraper;

in FIG. 10 - shows the operation of self-aligning pads when rotating counterclockwise;

in FIG. 11 shows the operation of the self-aligning pads during clockwise rotation;

in FIG. 12 schematically shows the displacement of blocks with a reduced axial width of the working surface relative to the lower block in one direction along the axis of the bearing;

in FIG. 13 - offset pads with reduced axial width of the working surface relative to the lower pads in opposite directions along the axis of the bearing;

in FIG. 14 schematically shows pads with a smaller axial width of the working surface, provided with a groove 0.5-1.5 mm deep along the entire circumferential length of the working surface in the central part of the block;

in FIG. 15 - pads with a smaller axial width of the working surface, provided with a groove depth corresponding to the thickness of the pads along the entire circumferential length of the pads in its central part;

in FIG. 16. schematically shows the pairing of the pads and the bearing housing on a spherical surface in accordance with the second embodiment of the technical solution.

Reversed plain bearing, FIG. 1-3; 5; 9, comprises a housing 1 with lubricant supply channels 2 and a drain cavity 3, a shaft 4 covered by self-aligning blocks 5, 6, each of which has hydrostatic pockets 7 on the backs of the block and radial holes 8 connected to them, located symmetrically relative to the center of the block, fixing screws 9 with spherical heads, oil scraper 10 installed in the inter-deck space, FIG. 9, in the body of the lower block 5, FIG. 5-8, under its working surface 11 there are channels 12 for supplying lubricant for additional cooling of the lower block 5, and in the bearing housing 1 holes 13 are additionally provided for supplying lubricant in channels 12 for additional cooling of the lower block 5, while on the working surface 11 of the lower pads, FIG. 2, 4, hydrostatic grease pockets 14 are additionally made, and an additional hole 15 is provided in the bearing housing 1 for supplying grease to the hydrostatic pockets 14 on the working surface of the lower block 5, each of the hydrostatic pockets

14 on the working surface 11 of the lower block 5 is connected to an additional hole

15 in the bearing housing 1 for supplying lubricant to the hydrostatic pockets 14 on the working surface 11 of the lower block 5 by means of channels 16 in the body of the lower block 5, in addition, the circumferential length (angle of coverage) and the axial width of the working surface 11 of the lower block 5 are larger than the circumferential the length and axial width of the working surface 17 of any other block 6 of the bearing.

Moreover, the channels 12 for additional cooling of the lower block are located either in the rear, or in the rear and front parts of the lower block 5, FIG. 6-7, symmetrically with respect to its longitudinal axis, hydrostatic pockets 14 on the working surface 11 of the lower block 5, FIG. 4, are made in the form of holes and are located in its central part symmetrically with respect to the longitudinal and transverse axis of the lower block 5.

In addition, pads 6 with a smaller axial width of the working surface 17 can be offset relative to the lower pads 5 in one direction or in opposite directions along the axis of the bearing, FIG. 12 and 13, respectively.

Moreover, each of the blocks 6 with a smaller axial width of the working surface 17 can be provided with a groove 18 with a depth of 0.5-1.5 mm or a groove 19 with a depth corresponding to the thickness of the block 6 along the entire circumferential length of the working surface in its central part, FIG. 14 and 15, respectively.

According to a second embodiment of the inventive bearing, the back of each of the bearing pads 5, 6, the surface of the housing 1, which mates with the back of the pads 5, 6, have a spherical shape, FIG. sixteen.

Reversible bearing operates as follows.

Before the rotation of the shaft 4, high-pressure grease is supplied to the hydrostatic pockets 14 on the working surface 11 of the lower block 5 through the channels 15 in the housing 1 and channels 16 in the body of the lower block 5. Under the action of high pressure in the hydrostatic pockets 14 on the working surface 11 of the lower block 6 the shaft 4 is detached from the working surface 11 by a certain amount of the thickness of the lubricating layer. Thus, the hydraulic lift of the shaft 4 in the bearing is carried out before starting the turbomachine.

After starting and some time to set the speed of rotation of the shaft 1, the supply of high-pressure lubricant to the hydrostatic pockets 14 on the working surface 11 of the lower block 5 is stopped, and the reversing bearing continues to work on the hydrodynamic film of the lubricant resulting from the involvement of the lubricant by rotating the shaft 4 on the working surfaces 11 and 17 self-aligning blocks 5 and 6, respectively.

After the start of rotation of the shaft 4 in the bearing, the lubricant, which is delivered by a directed oil supply from the oil supply system of the turbomachine through the channels 2 of the housing 1 to the oil scraper 10, enters the working surfaces 11 and 17 of the self-aligning blocks 5 and 6, respectively. Each of the self-aligning blocks rests on a self-generated hydrostatic lubricant film. This film is formed as a result of the selection of a small part (about 10%) of the hydrodynamic lubricant film on the working surfaces 11 and 17 of the self-aligning blocks 5 and 6 in order to create pressure in the pockets 7. The operation of the bearing is reversed by changing the pressure in the hydrostatic pockets 7 when changing the direction of rotation.

In FIG. 10 and 11 show the oil film pressure distribution between the shaft 4 and the self-aligning block 5 when the shaft rotates counterclockwise and clockwise, respectively.

Grease for additional cooling of the lower block 5 is delivered by directed oil supply from the oil supply system of the turbomachine through the channels 13 of the housing 1 to the channels 12 of the lower block 5 and, flowing through the channels 12 under the working surface 11 of the lower block 5, takes part of the heat from the thermally loaded zone of the working surface 11 and thereby additional cooling of the lower block 5. The flow of additional lubricant through the channels 12 can be carried out either in the rear, or in the rear and front parts of the lower block 5 simultaneously and regardless of the direction of rotation of the shaft 4 in the bearing.

The operation of the second embodiment of the inventive bearing is similar to that described above.

Claims (19)

1. Reversible sliding bearing, comprising a housing with lubricant supply channels and a drain cavity, a shaft covered by self-aligning blocks, each of which has hydrostatic pockets on the backs of the block and radial holes connected to them, located symmetrically with respect to the center of the block, fixing screws with spherical heads, oil scraper installed in the inter-deck space, characterized in that hydrostatic grease pockets are additionally made on the working surface of the lower block, and an additional hole is provided in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower block, each of the hydrostatic pockets on the working surface the bottom pads connected to an additional hole in the bearing housing for supplying lubricant to these hydrostatic pockets through channels in the body of the bottom pads. 2. A reversible plain bearing according to claim 1, characterized in that the hydrostatic pockets on the working surface of the lower block are located in its central part symmetrically with respect to the longitudinal and transverse axis of the lower block. 3. Reversible sliding bearing according to claim 1 or 2, characterized in that the hydrostatic pockets on the working surface of the lower pads are made in the form of holes. 4. Reversible plain bearing according to any one of paragraphs. 1-3, characterized in that in the body of the lower block under its working surface channels are made for additional cooling of the lower block, and the channels are located either in the rear, or in the rear and front parts of the lower block symmetrically with respect to its longitudinal axis. 5. The reversible plain bearing according to claim 1, characterized in that the circumferential length and axial width of the working surface of the lower block is greater than the circumferential length and axial width of the working surface of any other bearing block. 6. The reversible plain bearing according to claim 5, characterized in that the pads with a smaller axial width of the working surface are offset relative to the lower block in one direction along the axis of the bearing. 7. The reversible plain bearing according to claim 5, characterized in that the pads with a smaller axial width of the working surface are offset from the lower pads in opposite directions along the axis of the bearing. 8. The reversible plain bearing according to claim 5, characterized in that each of the pads with a smaller axial width of the working surface is provided with a groove 0.5-1.5 mm deep over the entire circumferential length of the working surface in the central part of the block. 9. The reversible plain bearing according to claim 5, characterized in that each of the blocks with a smaller axial width of the working surface is provided with a groove with a depth corresponding to the thickness of the block over the entire circumferential length of the block in its central part. 10. A reversible plain bearing, comprising a housing with lubricant supply channels and a drain cavity, a shaft covered by self-aligning blocks, each of which has hydrostatic pockets on the backs of the block and radial holes connected to them, located symmetrically relative to the center of the block, fixing screws with spherical heads, oil scraper installed in the inter-deck space, characterized in that the back of each of the bearing pads, the surface of the housing that mates with the back of the block, have a spherical shape. 11. The reversible plain bearing according to claim 10, characterized in that hydrostatic grease pockets are additionally made on the working surface of the lower block, and an additional hole is provided in the bearing housing for supplying grease to the hydrostatic pockets on the working surface of the lower block, each of which is hydrostatic the working surface of the lower pads is connected to an additional hole in the bearing housing for supplying lubricant to these hydrostatic pockets through channels in the body of the lower pads. 12. Reversible plain bearing according to claim 11, characterized in that the hydrostatic pockets on the working surface of the lower block are located in its central part symmetrically with respect to the longitudinal and transverse axis of the lower block. 13. Reversible sliding bearing according to claim 11 or 12, characterized in that the hydrostatic pockets on the working surface of the lower pads are made in the form of holes. 14. Reversible plain bearing according to any one of paragraphs. 11-13, characterized in that in the body of the lower block under its working surface channels are made for additional cooling of the lower block, moreover, these channels are located either in the rear, or in the rear and front parts of the lower block symmetrically with respect to its longitudinal axis. 15. The reversible plain bearing according to claim 11, characterized in that the circumferential length and axial width of the working surface of the lower block is greater than the circumferential length and axial width of the working surface of any other bearing block. 16. The reversible plain bearing according to claim 15, characterized in that the pads with a smaller axial width of the working surface are offset relative to the lower block in one direction along the axis of the bearing. 17. Reversible sliding bearing according to claim 15, characterized in that the pads with a smaller axial width of the working surface are offset from the lower pads in opposite directions along the axis of the bearing. 18. Reversible sliding bearing according to claim 15, characterized in that each of the pads with a smaller axial width of the working surface is provided with a groove with a depth of 0.5-1.5 mm over the entire circumferential length of the working surface in the central part of the block. 19. Reversible bearings according to claim 15, characterized in that each of the blocks with a smaller axial width of the working surface is provided with a groove with a depth corresponding to the thickness of the block over the entire circumferential length of the block in its central part.

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