Nuclear main pump medium self-lubricating guide bearing and carbon ring embedding method thereof

Abstract

The invention provides a nuclear main pump medium self-lubricating guide bearing and a carbon ring inlaying method thereof.The nuclear main pump medium self-lubricating guide bearing comprises a metal outer ring, and an annular protrusion is arranged on the outer wall of one end of the metal outer ring and used for fixing the metal outer ring in a bearing chamber; the carbon ring is embedded in the metal outer ring through interference fit; the rotating shaft penetrates through the carbon ring, and a gap exists between the outer wall of the rotating shaft and the inner wall of the carbon ring to serve as a flow channel for fluid medium circulation. The at least one flow guide through hole is formed in the metal outer ring and distributed in the circumferential direction of the metal outer ring at intervals; and the flow guide through hole is communicated with the flow channel and a return pipeline connected with the annular bulge to form a medium self-lubricating circulation loop, so that a fluid medium flows to the return pipeline along the flow guide through hole after flowing through the inner wall of the carbon ring along the flow channel. The guide bearing provided by the invention can bear an over-temperature working condition of 1.1 times of the maximum operating temperature, and has the advantages of simple structure, convenience in disassembly and assembly and durability.

Description

Technical Field

[0001] The invention belongs to the field of guide bearings for nuclear main pumps, and in particular relates to a medium self-lubricating guide bearing for a nuclear main pump and a carbon ring mounting method thereof. Background Art

[0002] The guide bearing is a key device to bear the radial force of the rotor. In addition to bearing the axial force, the guide bearing of the nuclear main pump must also withstand high temperature operating conditions from room temperature to about 350°C. Therefore, the structural design of the guide bearing of the nuclear main pump is very critical. On the one hand, it is necessary to ensure that the guide bearing still has an interference under over-temperature conditions, and on the other hand, it is necessary to prevent excessive interference from causing stress concentration and difficulty in installation. Summary of the invention

[0003] The purpose of the present invention is to provide a nuclear main pump medium self-lubricating guide bearing and a carbon ring installation method thereof. The nuclear main pump medium self-lubricating guide bearing structure can withstand an over-temperature condition of 1.1 times the maximum operating temperature, and at the same time has the advantages of excellent operating performance, simple structure, easy disassembly and assembly, and durability.

[0004] To achieve the above-mentioned purpose, the first aspect of the present invention provides a nuclear main pump medium self-lubricating guide bearing for supporting a rotating shaft, which includes: a metal outer ring, the outer wall of one end of which is provided with an annular protrusion for fixing the metal outer ring in a bearing chamber; a carbon ring, which is embedded in the metal outer ring by interference fit; the rotating shaft is arranged through the carbon ring, and there is a gap between the outer wall of the rotating shaft and the inner wall of the carbon ring as a flow channel for the fluid medium to flow; a plurality of guide holes, which are arranged in the metal outer ring and are distributed at intervals along the circumference of the metal outer ring; the guide holes connect the flow channel and the return pipeline connected to the annular protrusion to form a medium self-lubricating circulation loop, so that the fluid medium flows along the flow channel through the inner wall of the carbon ring and then flows along the guide holes to the return pipeline.

[0005] Optionally, the diameter of the flow-conducting hole ranges from 10 to 18 mm.

[0006] Optionally, the structure of the carbon ring is an integrated whole-segment carbon ring or is composed of several levels of segmented carbon rings.

[0007] Optionally, a groove is provided on the circumference of the annular protrusion, and a sealing ring is provided in the groove to seal the fluid medium in the guide hole.

[0008] Optionally, the annular protrusion is made integrally with the metal outer ring, and the surface of the annular protrusion is coated with a chrome coating.

[0009] A second aspect of the present invention provides a method for inserting a carbon ring of a nuclear main pump guide bearing, which is applicable to the above-mentioned nuclear main pump medium self-lubricating guide bearing, and comprises the following steps:

[0010] Calculate the theoretical minimum interference required for carbon ring installation under operating conditions min_required ;

[0011] Determine the minimum interference delta between the carbon ring and the metal outer ring min and the maximum interference δ max ; The minimum interference δ min Greater than the theoretical minimum interference δ min_required ;

[0012] According to the maximum interference δ max and the required gap Δ for mounting, calculate the mounting temperature t;

[0013] Putting the metal outer ring, the heat-insulating tooling and the thermocouple into a heating device and heating them to the mounting temperature t;

[0014] Measure whether the size change of the metal outer ring after heating meets the gap Δ required for the embedding; if so, insert the carbon ring into the metal outer ring; if not, continue heating until the size change of the metal outer ring meets the gap for the embedding.

[0015] Optionally, the operating condition is an over-temperature condition at 1.1 times the maximum operating temperature, and the theoretical minimum interference amount δ min_required The calculation formula is:

[0016] δ min_required =d f ×(α a -α i )×(1.1×t max -Δ t );

[0017] Among them, the d f is the basic size of the mating surface between the carbon ring and the metal outer ring; α a is the linear expansion coefficient of the metal outer ring; α i is the linear expansion coefficient of the carbon ring; t max is the maximum operating temperature; Δ t is the ambient temperature;

[0018] The method of determining the minimum interference and the maximum interference between the carbon ring and the metal outer ring comprises: based on the theoretical minimum interference δ min_required and the basic dimension d of the mating surface of the carbon ring and the metal outer ring f According to the tolerance band of the tolerance fit of the national standard, the fit tolerance of the metal outer ring and the carbon ring is determined; according to the fit tolerance, the minimum interference amount δ is calculated min and the maximum interference δ max .

[0019] Optionally, before calculating the mounting temperature, the stress distribution analysis of the metal outer ring and the carbon ring is also included. max Whether the stress of the lower guide bearing meets the requirements, the calculation formula of the maximum stress is:

[0020]

[0021] Among them, σ max is the maximum stress; P max is the maximum pressure at the fitting point under the maximum interference; max is the maximum interference; c is the material coefficient; d f C is the basic size of the mating surface between the carbon ring and the metal outer ring; a and C i are the rigidity coefficients of the metal outer ring and the carbon ring respectively; E a and E i are the elastic moduli of the metal outer ring and the carbon ring, respectively;

[0022] If the maximum interference δ max If the stress of the lower guide bearing is less than or equal to the maximum stress, the stress distribution of the guide bearing meets the requirements; otherwise, the stress distribution of the guide bearing does not meet the requirements, and the minimum interference amount δ is recalculated. min and the maximum interference δ max .

[0023] Optionally, the calculation formula for calculating the mounting temperature is:

[0024]

[0025] Where t is the mounting temperature; δ max is the maximum interference; Δ is the required clearance for installation; α a is the linear expansion coefficient of the metal outer ring; d f is the basic size of the mating surface of the carbon ring and the metal outer ring; Δt is the ambient temperature; after obtaining the mounting temperature t, the segmented level of the carbon ring is determined according to the length of the carbon ring, the mounting gap, and the shrinkage rate of the metal outer ring at temperature drop.

[0026] Optionally, the carbon ring installation method of the nuclear main pump guide bearing also includes: inserting the carbon ring into the metal outer ring step by step to complete the installation of all carbon rings at one time; pressing the carbon ring after installation, allowing the metal outer ring to cool and shrink naturally at room temperature, and after standing for a period of time, grinding the inner wall of the carbon ring into a finished product to complete the carbon ring installation.

[0027] In summary, compared with the prior art, the present invention provides a nuclear main pump medium self-lubricating guide bearing and its carbon ring installation method, which have the following beneficial effects: by setting a guide hole connecting the flow channel and the return line in the metal outer ring, a self-circulating loop of the fluid medium is realized, so that the nuclear main pump medium self-lubricating guide bearing structure of the present invention can withstand an over-temperature condition of 1.1 times the maximum operating temperature; at the same time, by setting the carbon ring as a segmented carbon ring, it is easier to install, preventing the carbon ring from getting stuck during installation, and reducing the wear on the carbon ring. Furthermore, through the carbon ring installation method, the installation of the carbon ring and the metal outer ring can be achieved more accurately, ensuring the installation accuracy of the two, and avoiding the problem of stress concentration and installation difficulties caused by excessive interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the medium self-lubricating guide bearing of the nuclear main pump of the present invention;

[0029] Figure 2 It is a schematic diagram of the assembly and circulation circuit of the medium self-lubricating guide bearing of the nuclear main pump of the present invention;

[0030] Figure 3 It is a schematic diagram of the carbon ring mounting of the medium self-lubricating guide bearing of the nuclear main pump of the present invention;

[0031] Figure 4 The present invention is a flow chart of the carbon ring installation of the medium self-lubricating guide bearing of the nuclear main pump. DETAILED DESCRIPTION

[0032] The following will be combined with the attached embodiment of the present invention Figure 1 ~Attached Figure 4 , the technical solutions, structural features, objectives achieved and effects in the embodiments of the present invention are described in detail.

[0033] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of 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.

[0034] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0035] The present invention provides a medium self-lubricating guide bearing for a nuclear main pump. The medium self-lubricating guide bearing for a nuclear main pump is installed in a bearing chamber 4 of the nuclear main pump when in use, and is used to support a rotating shaft 3. Figure 1 and Figure 2 As shown, the medium self-lubricating guide bearing of the nuclear main pump comprises: a metal outer ring 1, the outer wall of one end of which is provided with an annular protrusion 101 for fixing the metal outer ring 1 in the bearing chamber 4; a carbon ring 2, which is embedded in the metal outer ring 1 by means of interference fit through the matching surface 103 between the outer wall of the carbon ring 2 and the inner wall of the metal outer ring 1; the rotating shaft 3 is arranged through the carbon ring 2, and there is a gap between the outer wall of the rotating shaft 3 and the inner wall 201 of the carbon ring 2 as a flow channel 211 for the fluid medium to flow; at least one guide The flow holes 102 are arranged in the metal outer ring and are distributed at intervals along the circumference of the metal outer ring 1; the guide holes 102 connect the flow channel 211 and the return line 113 connected to the annular protrusion 101 to form a medium self-lubricating circulation loop, so that the fluid medium flows along the flow channel 211 through the inner wall 201 of the carbon ring and then flows along the guide holes 102 to the return line 113, and the return line 113 transports the fluid medium back to the guide bearing to complete the circulation of the fluid medium.

[0036] Since the medium self-lubricating guide bearing of the nuclear main pump provided by the present invention is used in a nuclear power plant, the metal outer ring 1 is made of 1.4313 martensitic stainless steel, which has high strength, high corrosion resistance and high temperature resistance, and can withstand the circulation of high temperature and high pressure media in the loop system of a nuclear power plant. Further, in this embodiment, a guide hole 102 is arranged in the circumference of the metal outer ring 1, and the diameter of the guide hole 102 ranges from 10 to 18 mm. By setting the diameter of the guide hole to 10 to 18 mm, on the one hand, it is prevented that the diameter of the guide hole 102 is too small to hinder the circulation of the fluid medium, the flow capacity is insufficient, and sufficient circulation flow cannot be formed. At the same time, the aperture is too small, which makes the processing difficult and the production cost high; on the other hand, the diameter of the guide hole 102 is too large, which causes the wall thickness of the metal outer ring to be insufficient, and it is easy to deform during the shrink-fitting process, causing safety hazards. Preferably, the diameter of the guide hole 102 is 15 mm, and the fluid medium is water, which serves as a lubricating medium and a heat dissipation medium. In other embodiments, the number of the flow-conducting holes 102 is 3 to increase the flow capacity of the fluid medium. The specific number of the flow-conducting holes 102 can be set according to actual heat dissipation requirements, flow requirements, and lubrication requirements.

[0037] Further, if Figure 2 As shown, the rotating shaft 3 includes a shaft body 31 and a shaft sleeve 32 sleeved on the outer wall of the shaft body 31. There is a gap between the outer wall of the shaft sleeve 32 and the inner wall of the carbon ring 2, forming the flow channel 211, so that the fluid medium can flow along the flow channel 211 to achieve lubrication and heat dissipation.

[0038] Among them, Figure 1 and Figure 2 As shown, when the medium self-lubricating guide bearing of the nuclear main pump formed by the carbon ring 2 and the metal outer ring 1 is installed in the bearing chamber 4, the metal outer ring 1 and the carbon ring 2 embedded in the metal outer ring 1 are simultaneously suspended in the bearing chamber 4, so that a cavity 41 is formed between the metal outer ring 1 and the carbon ring 2 and the bottom wall of the bearing chamber 4, and the guide holes 102 are all connected to the cavity 41, and the guide holes 102 and the flow channel 211 are connected through the cavity 41. Further, as Figure 2 As shown, the guide hole 102 includes a first through hole 121 and a second through hole 122. The first through hole 121 is horizontally arranged in the annular protrusion 101, and one end is connected to the return pipe 113; the second through hole 122 is vertically arranged along the axial direction of the metal outer ring 1, one end is connected to the first through hole 121, and the other end is connected to the cavity 41, thereby forming a medium self-lubricating circulation loop, so that the fluid medium flowing through the inner wall 201 of the carbon ring can flow into the cavity 41 and return to the return pipe 113 through the guide hole 102. The structure is simple and compact, and the self-lubricating function of the fluid medium is realized.

[0039] Among them, Figure 1 As shown, a groove 111 is provided around the annular protrusion 101 , and a sealing ring (such as an O-ring) is provided in the groove 111 to seal the fluid medium in the guide hole 102 to prevent leakage of the fluid medium.

[0040] Further, if Figure 1 As shown, the annular protrusion 101 is made integrally with the metal outer ring 1, and the surface of the annular protrusion 101 is coated with a chrome coating 112 to enhance its surface wear resistance and avoid wear caused by repeated disassembly and assembly. The chrome coating 112 can be formed by a surface spraying process such as electroplating or explosion spraying. Furthermore, the surface of the chrome coating 112 can be ground to improve the surface finish of the chrome coating 112, which is beneficial to the disassembly and assembly of the medium self-lubricating guide bearing of the nuclear main pump.

[0041] Among them, Figure 1 The structure of the carbon ring 2 shown is a whole carbon ring made in one piece; in other embodiments, such as Figure 3 As shown, the structure of the carbon ring 2 is composed of several levels of segmented carbon rings ( Figure 3 Compared with a whole carbon ring, the carbon ring 2 composed of several stages of segmented carbon rings is easy to install, and effectively prevents the carbon ring 2 from being too long and getting stuck on the metal outer ring 1, so that the carbon ring 2 cannot be completely embedded in the metal outer ring 1.

[0042] Since the installation of the carbon ring 2 is the key process of the medium self-lubricating guide bearing of the nuclear main pump, the installation of the carbon ring 2 and the metal outer ring 1 is carried out by shrink fitting, such as Figure 3 As shown, the metal outer ring 1 is placed in the heat preservation tooling 4, and the heat preservation tooling 4 is used to keep the heated metal outer ring 1 warm to prevent the metal outer ring 1 from cooling and shrinking too quickly during the installation process. In the process of heating the metal outer ring 1, a thermocouple 5 is arranged on the surface of the annular protrusion 101 at the top and the bottom of the metal outer ring 1 to continuously measure the temperature change of the metal outer ring 1. The carbon ring 2 can be designed as a whole carbon ring or a segmented carbon ring. Regardless of the design, when the temperature of the metal outer ring 1 reaches the requirement, all carbon rings 2 should be installed in the metal outer ring 1 at the same time. After the metal outer ring 1 and the carbon ring 2 are cooled and left to stand for a period of time, the inner wall 201 of the carbon ring 2 is ground to the finished product size.

[0043] Specifically, the present invention also provides a method for installing a carbon ring of a nuclear main pump guide bearing, which is applicable to the nuclear main pump medium self-lubricating guide bearing as described above, such as Figure 4 As shown, it includes the following steps:

[0044] S1. Calculate the theoretical minimum interference required for carbon ring installation under operating conditions. min_required ;

[0045] The operating condition is an over-temperature condition at 1.1 times the maximum operating temperature, and the theoretical minimum interference amount δ min_required The calculation formula is:

[0046] δ min_required =d f ×(α a -α i )×(1.1×t max -Δ t );

[0047] Among them, the d f is the basic size of the mating surface between the carbon ring and the metal outer ring; α a is the linear expansion coefficient of the metal outer ring; α i is the linear expansion coefficient of the carbon ring; t max is the maximum operating temperature; Δ t is the ambient temperature;

[0048] S2. Determine the minimum interference delta between the carbon ring and the metal outer ring min and the maximum interference δ max ; The minimum interference δ min Greater than the theoretical minimum interference δ min_required ;

[0049] The minimum interference amount δ for the carbon ring and the metal outer ring is determined as follows: min and the maximum interference δ max Including: Based on the theoretical minimum interference δ min_required and the basic dimension d of the mating surface of the carbon ring and the metal outer ring f According to the tolerance band of the tolerance fit of the national standard (such as GB / T 1800.3-1998), the fit tolerance of the metal outer ring and the carbon ring is determined; according to the fit tolerance, the minimum interference amount δ is calculated min and the maximum interference δ max .

[0050] The tolerance zone determines the tightness of the fit: the wider the tolerance zone, the looser the fit; the narrower the tolerance zone, the tighter the fit. In a specific embodiment, if the basic size of the metal outer ring 1 is d f1 , the tolerance of the metal outer ring 1 is ±δ1, and the basic size of the carbon ring 2 is d f2 , the tolerance of the carbon ring 2 is ±δ2, then the size range of the metal outer ring 1 is [d f1 -δ1,d f1 +δ1], the size range of the carbon ring 2 is [d f2 -δ2,d f2+δ2], and then get the minimum interference δ min =(d f1 -δ1)-(d f2 +δ2), maximum interference δ max =(d f1 +δ1)-(d f2 -δ2).

[0051] S3. Analysis of stress distribution of metal outer ring and carbon ring. max Whether the stress of the lower guide bearing meets the requirements, the calculation formula of the maximum stress is:

[0052]

[0053] Among them, σ max is the maximum stress; P max is the maximum pressure at the fitting point under the maximum interference; max is the maximum interference; c is the material coefficient; d f C is the basic size of the mating surface between the carbon ring and the metal outer ring; a and C i are the rigidity coefficients of the metal outer ring and the carbon ring respectively; E a and E i are the elastic moduli of the metal outer ring and the carbon ring, respectively;

[0054] If the maximum interference δ max If the stress of the lower guide bearing is less than or equal to the maximum stress, the stress distribution of the guide bearing meets the requirements; otherwise, the stress distribution of the guide bearing does not meet the requirements, and return to steps S1 to S2 to recalculate and determine the minimum interference δ min and the maximum interference δ max .

[0055] S4, according to the maximum interference δ max and the required gap Δ for mounting, calculate the mounting temperature t;

[0056] Wherein, the calculation formula for calculating the mounting temperature is:

[0057]

[0058] Where t is the mounting temperature; δ max is the maximum interference; Δ is the required clearance for installation; α a is the linear expansion coefficient of the metal outer ring; d f is the basic size of the mating surface of the carbon ring and the metal outer ring; Δt is the ambient temperature.

[0059] S5. After obtaining the mounting temperature t, determine the number of segmented carbon rings according to the length of the carbon ring, the mounting gap, and the shrinkage rate of the metal outer ring when the temperature drops, that is, determine how many segmented carbon rings the carbon ring 2 includes. In this embodiment, the number of segmented carbon rings 2 is 3.

[0060] S6. Measure whether the size change of the metal outer ring 1 after heating satisfies the gap Δ required for embedding; if so, insert the carbon ring 2 into the metal outer ring 1; if not, continue heating until the size change of the metal outer ring 1 satisfies the gap Δ required for embedding.

[0061] S7, placing the metal outer ring 1, the heat-insulating tooling 4 and the thermocouple 5 into a heating device and heating them to the mounting temperature t; in this embodiment, the mounting temperature t does not exceed 475°C.

[0062] S8, gradually inserting the carbon ring 2 into the metal outer ring 1, completing the installation of all the carbon rings 2 at one time; after the installation, the carbon ring 2 is pressed tightly, and the metal outer ring 1 naturally cools and shrinks at room temperature. After standing for a period of time (for example, 2 weeks), the inner wall 201 of the carbon ring is ground into a finished product, and the installation of the carbon ring 2 is completed.

[0063] In summary, compared with the prior art, the medium self-lubricating guide bearing of the nuclear main pump and the carbon ring installation method thereof provided by the present invention realize the self-circulation loop of the fluid medium by setting at least one guide hole 102 connecting the flow channel 211 and the return line 113 in the metal outer ring 1, so that the medium self-lubricating guide bearing structure of the nuclear main pump of the present invention can withstand an over-temperature condition of 1.1 times the maximum operating temperature; at the same time, by setting the carbon ring 2 as a segmented carbon ring, it is easier to install, preventing the carbon ring 2 from being stuck during installation, and reducing the wear on the carbon ring 2. Furthermore, through the carbon ring installation method, the installation of the carbon ring 2 and the metal outer ring 1 can be achieved more accurately, ensuring the installation accuracy of the two, and avoiding the problem of stress concentration and installation difficulty caused by excessive interference.

[0064] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A medium self-lubricating guide bearing for a nuclear main pump, used to support a rotating shaft, characterized in that: include: A metal outer ring, the outer wall of which has one end provided with an annular protrusion, which is used to fix the metal outer ring in the bearing chamber; A carbon ring is embedded in the metal outer ring through interference fit; the rotating shaft is arranged through the carbon ring, and a gap between the outer wall of the rotating shaft and the inner wall of the carbon ring serves as a flow channel for the fluid medium to flow; A plurality of guide holes are arranged in the metal outer ring and are distributed at intervals along the circumference of the metal outer ring; The guide hole connects the flow channel and the return pipeline connected to the annular protrusion to form a medium self-lubricating circulation loop, so that the fluid medium flows along the flow channel through the inner wall of the carbon ring and then flows along the guide hole to the return pipeline.

2. The medium self-lubricating guide bearing of the nuclear main pump according to claim 1, characterized in that: The diameter of the flow-conducting hole ranges from 10 to 18 mm.

3. The medium self-lubricating guide bearing of the nuclear main pump according to claim 1, characterized in that: The structure of the carbon ring is a whole carbon ring made in one piece or is composed of several levels of segmented carbon rings.

4. The medium self-lubricating guide bearing of the nuclear main pump according to claim 1, characterized in that: A groove is arranged around the annular protrusion, and a sealing ring is arranged in the groove to seal the fluid medium in the guide hole.

5. The medium self-lubricating guide bearing of the nuclear main pump according to claim 1, characterized in that: The annular protrusion is made in one piece with the metal outer ring, and the surface of the annular protrusion is coated with a chrome coating.

6. A method for inserting a carbon ring of a nuclear main pump guide bearing, applicable to the medium self-lubricating guide bearing of a nuclear main pump as claimed in any one of claims 1 to 5, characterized in that: include: Calculate the theoretical minimum interference required for carbon ring installation under operating conditions min_required ; Determine the minimum interference delta between the carbon ring and the metal outer ring min and the maximum interference δ max ; The minimum interference δ min Greater than the theoretical minimum interference δ min_required ; According to the maximum interference δ max and the required gap Δ for mounting, calculate the mounting temperature t; Putting the metal outer ring, the heat-insulating tooling and the thermocouple into a heating device and heating them to the mounting temperature t; Measure whether the size change of the metal outer ring after heating meets the gap Δ required for the embedding; if so, insert the carbon ring into the metal outer ring; if not, continue heating until the size change of the metal outer ring meets the gap for the embedding.

7. The carbon ring mounting method according to claim 6, characterized in that: The operating condition is an over-temperature condition at 1.1 times the maximum operating temperature, and the theoretical minimum interference amount δ min_required The calculation formula is: d min_required =d f ×(a a -a i )×(1.1×t max -D t ); Among them, the d f is the basic size of the mating surface between the carbon ring and the metal outer ring; α a is the linear expansion coefficient of the metal outer ring; α i is the linear expansion coefficient of the carbon ring; t max is the maximum operating temperature; Δ t is the ambient temperature; The method of determining the minimum interference and the maximum interference between the carbon ring and the metal outer ring comprises: based on the theoretical minimum interference δ min_required and the basic dimension d of the mating surface of the carbon ring and the metal outer ring f According to the tolerance band of the tolerance fit of the national standard, the fit tolerance of the metal outer ring and the carbon ring is determined; according to the fit tolerance, the minimum interference amount δ is calculated min and the maximum interference δ max .

8. The carbon ring mounting method according to claim 6, characterized in that: Before calculating the mounting temperature, the stress distribution analysis of the metal outer ring and the carbon ring is also included. max Whether the stress of the lower guide bearing meets the requirements, the calculation formula of the maximum stress is: Among them, σ max is the maximum stress; P max is the maximum pressure at the fitting point under the maximum interference; max is the maximum interference; c is the material coefficient; d f C is the basic size of the mating surface between the carbon ring and the metal outer ring; a and C i are the rigidity coefficients of the metal outer ring and the carbon ring respectively; E a and E i are the elastic moduli of the metal outer ring and the carbon ring, respectively; If the maximum interference δ max If the stress of the lower guide bearing is less than or equal to the maximum stress, the stress distribution of the guide bearing meets the requirements; otherwise, the stress distribution of the guide bearing does not meet the requirements, and the minimum interference amount δ is recalculated. min and the maximum interference δ max .

9. The carbon ring mounting method according to claim 6, characterized in that: The calculation formula for calculating the mounting temperature is: Where t is the mounting temperature; δ max is the maximum interference; Δ is the required clearance for installation; α a is the linear expansion coefficient of the metal outer ring; d f is the basic size of the mating surface of the carbon ring and the metal outer ring; Δt is the ambient temperature; After the embedding temperature t is obtained, the segmentation level of the carbon ring is determined according to the length of the carbon ring, the embedding gap, and the shrinkage rate of the metal outer ring when the temperature drops.

10. The carbon ring mounting method according to claim 9, characterized in that: Also includes: The carbon rings are inserted into the metal outer ring step by step, and all the carbon rings are installed at one time; after the installation, the carbon rings are pressed tightly, and the metal outer rings are naturally cooled and contracted at room temperature. After standing for a period of time, the inner wall of the carbon ring is ground to a finished product, and the carbon ring installation is completed.

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