A method for adjusting the circumferential clearance of a thrust pad bearing in a marine gearbox

Abstract

This invention discloses a method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox. First, the thrust bearing assembly, excluding the partition plate, is installed. Using a reference transfer method, the position of the output shaft centerline after installation is determined. The positional relationship between the output shaft centerline and the bearing hole centerline of the bearing housing is established through the radial clearance and offset angle α of the supporting bearing. The distance from the reference surface to the arc of the thrust bearing is measured. The position of the center of the two corresponding thrust bearing blocks is determined using the principle of drawing circles at three points on the arc. The symmetrical position of the two thrust bearing blocks during final assembly is determined using the perpendicular line connecting the centers. This process determines the machining drawing of the arcs on both sides of the partition plate. After machining, the total circumferential clearance of the thrust bearing is determined based on the dimensional inspection report and the radius value of the thrust bearing blocks.

Description

Technical Field

[0001] This invention relates to the field of thrust bearing assembly technology, and specifically to a method for adjusting the circumferential clearance of thrust bearings in marine gearboxes. Background Technology

[0002] Thrust bearings are crucial mechanical components, possessing strong axial load-bearing capacity and self-lubricating properties. They are simple in structure, low in maintenance and replacement costs, and highly adaptable, making them widely used in industrial production and machinery manufacturing, and an indispensable key component. Especially in the main propulsion transmission systems of large ships, marine gearboxes, as vital equipment in the propulsion system, have thrust bearings located on both sides of the thrust flange of the output shaft of high-power marine gearboxes to withstand the forward and reverse thrust generated by the propeller during navigation. Marine gearbox forward and reverse thrust bearings are generally composed of multiple thrust pads, symmetrically arranged circumferentially on both sides of the thrust flange of the output shaft. To ensure reliable and stable operation of the forward or reverse thrust bearings in the circumferential direction, and to prevent large-scale rotation or oscillation of the individual thrust pads and the possibility of collisions between adjacent thrust pads, they must be confined within a certain circumferential range by partitions.

[0003] The thrust bearing assembly includes a gearbox and an output shaft passing through the gearbox. A thrust flange, co-centered with the output shaft, is mounted on the shaft body within the gearbox cavity. A support bearing is installed between the output shaft and the bearing hole in the gearbox. Multiple thrust pads and a ring assembly supporting these thrust pads are respectively arranged on both sides of the thrust flange. The thrust pads on the same side are arranged around the centerline of the bearing hole in the gearbox and are close together, forming a total circumferential clearance between two adjacent thrust pads on the same side. An observation hole communicating with the gearbox cavity is opened at the position corresponding to the total circumferential clearance on the top of the gearbox. A cover mounting plane is provided on the top surface of the gearbox corresponding to the observation hole. A cover is installed at the observation hole and used to shield the observation hole. The inner surface of the cover is used for fixed connection to the upper end of a partition. However, during assembly, adjustment, and implementation, on the one hand, the amount of machining on the partition's arc surface needs to be determined multiple times through a "trial machining method," and the partition needs to be assembled and disassembled repeatedly to check the total circumferential clearance, resulting in low adjustment efficiency. On the other hand, due to the limitations of the gearbox structure, the total circumferential clearance of the thrust bearing can only be determined visually, and the circumferential clearance cannot be quantitatively evaluated, leading to different evaluation results from inspectors and making it difficult to guarantee the assembly accuracy of the key dimensions of the thrust bearing. Therefore, how to solve the problem of the amount of machining on the partition in one go, improve the assembly efficiency of the thrust bearing in the circumferential direction, and quantitatively determine the assembly dimensional accuracy of the thrust bearing in the circumferential direction is an important problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a method for adjusting the circumferential clearance of thrust bearings in marine gearboxes, which improves the adjustment efficiency of the partition, reduces the influence of human factors, and ensures the installation dimensional accuracy and assembly performance of the thrust bearing.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for adjusting the circumferential clearance of thrust bearings in marine gearboxes involves using the mounting surface of a partition plate as a measurement reference plane. On the projection plane along the output shaft centerline, the extension line of the shortest distance between the outer circle of the thrust flange on the output shaft and the measurement reference plane is used as a mark line HH. Using the formula ΔL = Sinα × δ / 2, where δ is the radial clearance between the output shaft and the support bearing in a static state, and α is the angle between the measurement reference plane and the horizontal plane, the mark line JJ of HH, based on the offset distance ΔL, is obtained. The projection line G of the measurement reference plane on the projection plane along the output shaft centerline is then used as the final mark line. Establish a central coordinate system using G and the marking line JJ. By measuring the positional relationship of the outer circles of two adjacent thrust pads located on both sides of the total circumferential clearance in the central coordinate system, determine the positions of the centers of the two thrust pads in the central coordinate system. Use the perpendicular bisector of the line connecting the centers of the two thrust pads as the center line of the partition's projection along the output shaft centerline. Use the projection line GG as the installation reference line of the partition to establish the positional relationship between the partition and the two adjacent thrust pads on both sides of the total circumferential clearance. Obtain the machining radius dimensions of the arcs on both sides of the partition. Based on the actual radius dimensions of the outer circles of the two thrust pads, the value of the total circumferential clearance can be calculated.

[0007] As an optimization, when determining the positions of the centers of the two thrust pads in the central coordinate system, at least three different positions on the outer circles of the two thrust pads are used as measurement points on the projection plane along the center line of the output shaft. The distance L between the measurement points and the marking line JJ and the distance H between the measurement points and the projection line GG are measured respectively to obtain the positions of the measurement points based on the central coordinate system. According to the principle of the three-point center determination method, the positions of the centers of the two thrust pads in the central coordinate system are then determined.

[0008] As an optimization, after determining the perpendicular bisector of the line connecting the centers of the two thrust pads, the positions of the two adjacent thrust pads located on both sides of the total circumferential clearance are adjusted so that the perpendicular bisector of the line connecting the centers of the two thrust pads coincides with the marking line JJ, that is, the center line of the partition projected along the output shaft centerline coincides with the perpendicular bisector of the line connecting the centers of the two thrust pads.

[0009] As an optimization, the machining radius of the arc on the partition plate is R = R′ + (K ± T) / 2, where the nominal size of the total circumferential clearance is K = (maximum value + minimum value of the total circumferential clearance requirement) / 2, the tolerance is T = (maximum value - minimum value of the total circumferential clearance requirement) / 2, and R′ is the actual radius of the outer circle of the thrust pad, ensuring the consistency of the ± sign in the calculation formula of the machining radius of the arc on both sides of the partition plate.

[0010] As an optimization, a reference transfer method is adopted, in which a reference measuring block is fixed on the gearbox body corresponding to the position of the thrust flange and the thrust pad on the output shaft, and the measuring reference surface is transferred to the measuring surface parallel to it on the reference measuring block.

[0011] Compared with existing technologies, this invention establishes a unified reference plane for measuring the distance between the thrust bearing block and the outer circle of the thrust flange on the output shaft by using the reference transfer method and the reference measuring block measuring surface. This reduces measurement errors caused by inconsistent references and also makes it easier for operators to perform measurements.

[0012] By using the shortest distance from a straight line to a plane, the shortest distance from the reference plane to the outer circle of the thrust flange is measured. This determines that the position of the output shaft centerline after the thrust bearing is installed must be on the mark line HH. At the same time, the positional relationship between the output shaft centerline and the bearing hole centerline of the gearbox is established by using the radial clearance δ and offset angle α of the support bearing. This determines that the position of the bearing hole centerline on the gearbox must be on the mark line JJ, and this is used as the measurement reference.

[0013] After measuring the distance from the reference plane to the arc of the thrust bearing, the position of the center of the thrust bearing is determined by using the principle of drawing a circle with three points on the arc, and the position of the center point of the bearing hole in the housing is determined by using the vertical line of the line connecting the centers.

[0014] The symmetrical position of the thrust pads during final assembly is determined by the angle between the vertical line (symmetry line) connecting the centers of the thrust pads and the measurement reference line. When the angle is zero, it indicates that the thrust pads are assembled in a symmetrical position. When the angle is not zero, it indicates that the thrust pads are assembled in an asymmetrical position. In this case, the entire thrust pad needs to be rotated relative to the center point of the bearing hole in the housing by a corresponding angle so that it coincides with the measurement reference line to determine the installation position and distance of the thrust pads.

[0015] Considering the actual assembly state and the final machining positioning datum of the partition, a positional relationship diagram between the partition and the thrust pad is established, and the machining diagram of the arcs on both sides of the partition and the alignment datum during machining are determined. This solves the machining dimensions of the partition in one go, improves adjustment efficiency and reduces machining costs.

[0016] Based on the inspection report of the partition size and the radius value of the thrust bearing, the total clearance in the circumferential direction of the side thrust bearing can be quantitatively determined, reducing the problem of different evaluation results caused by different inspectors, and ensuring the assembly accuracy of the key dimensions of the thrust bearing. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention;

[0018] Figure 2 This is an axial sectional view of the thrust bearing structure of the present invention;

[0019] Figure 3 This is a radial sectional view of the thrust bearing structure of the present invention;

[0020] Figure 4 This is a schematic diagram of the actual installation of the thrust bearing and the arrangement of various measuring points in this invention;

[0021] Figure 5 for Figure 4 Rotate view from A direction;

[0022] Figure 6 This is a diagram confirming the center and installation position of the thrust bearing block in this invention;

[0023] Figure 7 This is a diagram showing the position change process of the thrust bearing blocks and the confirmation of the installation distance in this invention;

[0024] Figure 8 This is a diagram showing the machining dimensions of the partition arc in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] like Figures 1 to 8As shown in the figure, a method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox is described. The mounting surface of the partition 1 is used as the measurement reference surface. The output shaft 2 is axially pushed to fix the thrust flange on it to the thrust bearing 4 on the measurement side. On the projection plane along the centerline of the output shaft 2, the extension line of the shortest distance between the outer circle of the thrust flange on the output shaft 2 and the measurement reference surface is used as the mark line HH. According to the formula ΔL = Sinα × δ / 2, where δ is the radial clearance between the output shaft 2 and the support bearing 3 in a static state, and α is the angle between the measurement reference surface and the horizontal plane, the mark line HH is obtained as the mark line JJ based on the offset distance ΔL. The measurement reference surface... A central coordinate system is established on the projection line GG and the marking line JJ on the projection surface along the center line of the output shaft 2. By measuring the positional relationship of the outer circles of the two adjacent thrust pads 4 located on both sides of the total circumferential clearance in the central coordinate system, the positions of the centers of the two thrust pads 4 in the central coordinate system are determined. The perpendicular bisector of the line connecting the centers of the two thrust pads 4 is taken as the center line of the projection of the partition 1 along the center line of the output shaft 2, and the projection line GG is taken as the installation reference line of the partition 1. The positional relationship between the partition 1 and the two adjacent thrust pads 4 on both sides of the total circumferential clearance is established, and the machining radius of the arc on both sides of the partition 1 is obtained. Based on the actual radius of the outer circles of the two thrust pads 4, the value of the total circumferential clearance can be obtained.

[0028] Measure multiple distances h, h1, h2, h3, h4, ... from the reference plane to the outer circle of the thrust flange on the output shaft 2. Based on the minimum measured value, determine the position of the marking line HH. That is, the projection point O1 of the center line of the output shaft 2 must be on the marking line HH. In the static state after assembly, the center line of the output shaft 2 is not in the same position as the center line of the bearing hole. The center line of the output shaft 2 in the static state is lower than the center line of the bearing hole by δ / 2. Then, the marking line JJ after the offset distance ΔL of the marking line HH can be obtained by formula. That is, the projection point O of the center line of the bearing hole of the gearbox 5 on the projection plane must be on the marking line JJ. In addition, when 0 < α < 90°, the marking line JJ is to the right of the marking line HH; when -90° < α < 0°, the marking line JJ is to the left of the marking line HH; when α = 0°, the marking line JJ coincides with the marking line HH, that is, there is no offset.

[0029] In this specific embodiment, when determining the positions of the centers of the two thrust pads 4 in the central coordinate system, at least three different positions on the outer circles of the two thrust pads 4 are used as measurement points on the projection plane along the center line of the output shaft 2. The distance L between the measurement point and the mark line JJ and the distance H between the measurement point and the projection line GG are measured respectively. That is, the first measurement position AA (distance L1), the second measurement position BB (distance L2), the third measurement position CC (distance L3), the fourth measurement position DD (distance L4), the fifth measurement position EE (distance L5), and the sixth measurement position FF (distance L6) are determined by positioning with the mark line JJ. The distances AA1, BB1, CC1, DD1, EE1, and FF1 from the measurement reference plane to the corresponding positions on the outer circles of the thrust pads 5 are measured using a depth gauge and recorded as H3, H2, H1, H6, H5, and H4 respectively. The positions of the measurement points based on the central coordinate system are obtained. According to the principle of the three-point center determination method, the positions of the centers of the two thrust pads 4 in the central coordinate system are then determined. That is, after connecting A1B1, B1C1, D1E1, and E1F1, draw perpendicular lines to each line segment from the center point. Then, the intersection point M of the perpendicular lines A1B1 and B1C1, and the intersection point N of the perpendicular lines D1E1 and E1F1 can be obtained. In other words, the center of the circle after the actual installation of one thrust pad 4 is M, and the center of the circle after the actual installation of the other thrust pad 4 is N.

[0030] In this specific embodiment, after determining the perpendicular bisector OO2 of the line connecting the centers of the two thrust pads 4, based on the perpendicular bisector...

[0031] Adjust the angle β between OO2 and the marking line JJ, and adjust the positions of the two adjacent thrust pads 4 located on both sides of the total circumferential gap so that the perpendicular bisector OO2 of the line connecting the centers of the two thrust pads 4 coincides with the marking line JJ. That is, the center line of the partition 1 projected along the center line of the output shaft 2 coincides with the perpendicular bisector OO2 of the line connecting the centers of the two thrust pads 4.

[0032] In this specific embodiment, the machining radius dimension R of the arc on the partition 1 is R = R′ + (K ± T) / 2, where the nominal dimension of the total circumferential clearance K = (maximum value + minimum value of the total circumferential clearance requirement) / 2, the tolerance T = (maximum value - minimum value of the total circumferential clearance requirement) / 2, and R′ is the actual radius dimension of the outer circle of the thrust pad 4, ensuring the consistency of the ± sign in the calculation formula of the machining radius dimension of the arc on both sides of the partition 1.

[0033] In this specific embodiment, a reference transfer method is adopted. A reference measuring block 6 is fixed on the gearbox 5 at the position corresponding to the thrust flange and thrust bearing 4 on the output shaft 2. The measuring reference surface is then transferred to a measuring surface parallel to it on the reference measuring block 6. The bottom and top surfaces of the reference measuring block 6 are parallel. The bottom surface of the reference measuring block 6 is fixed to the measuring reference surface, ensuring that a feeler gauge with a tolerance of 0.02mm cannot pass through. After passing this requirement, the reference measuring block 6 is fixed to prevent movement or shaking during subsequent measurements.

[0034] This invention can solve the problem of the amount of processing of the partition plate in one go, improve the adjustment efficiency of the partition plate, and avoid the influence of human factors (visual inspection). It can quantitatively evaluate the total clearance in the circumferential direction of the thrust bearing, and ensure the dimensional accuracy and assembly performance of the thrust bearing in the circumferential direction. This invention has the advantages of simple operation, high efficiency, low cost, high dimensional and assembly accuracy, and wide applicability.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox, characterized in that: Using the mounting surface of the partition as the measurement reference plane, on the projection plane along the output shaft centerline, the extension line of the shortest distance between the outer circle of the thrust flange on the output shaft and the measurement reference plane is used as the mark line HH. According to the formula ΔL=Sinα×δ / 2, where δ is the radial clearance between the output shaft and the support bearing in a static state, and α is the angle between the measurement reference plane and the horizontal plane, the mark line JJ based on the offset distance ΔL is obtained from the mark line HH. A center coordinate system is established using the projection line GG of the measurement reference plane on the projection plane along the output shaft centerline and the mark line JJ. The system is established by measuring the positional relationship of the outer circles of two adjacent thrust pads on both sides of the total circumferential clearance in the central coordinate system. The positions of the centers of the two thrust pads in the central coordinate system are determined. The perpendicular bisector of the line connecting the centers of the two thrust pads is used as the center line of the projection of the partition along the output shaft centerline. The projection line GG is used as the installation reference line of the partition. The positional relationship between the partition and the two adjacent thrust pads on both sides of the total circumferential clearance is established, and the machining radius of the arc on both sides of the partition is obtained. Based on the actual radius of the outer circles of the two thrust pads, the value of the total circumferential clearance can be obtained.

2. The method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox according to claim 1, characterized in that: When determining the positions of the centers of the two thrust pads in the central coordinate system, at least three different positions on the outer circles of the two thrust pads are used as measurement points on the projection plane along the center line of the output shaft. The distance L between the measurement points and the marking line JJ and the distance H between the measurement points and the projection line GG are measured respectively to obtain the positions of the measurement points based on the central coordinate system. According to the principle of the three-point center determination method, the positions of the centers of the two thrust pads in the central coordinate system are then determined.

3. The method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox according to claim 1, characterized in that: After determining the perpendicular bisector of the line connecting the centers of the two thrust pads, adjust the positions of the two adjacent thrust pads located on both sides of the total circumferential clearance so that the perpendicular bisector of the line connecting the centers of the two thrust pads coincides with the marking line JJ. That is, the center line of the partition projected along the output shaft centerline coincides with the perpendicular bisector of the line connecting the centers of the two thrust pads.

4. The method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox according to claim 1, characterized in that: The machining radius of the arc on the partition plate is R = R′ + (K ± T) / 2, where the nominal size of the total circumferential clearance is K = (maximum value + minimum value of the total circumferential clearance requirement) / 2, the tolerance is T = (maximum value - minimum value of the total circumferential clearance requirement) / 2, and R′ is the actual radius of the outer circle of the thrust pad, ensuring the consistency of the ± sign in the calculation formula of the machining radius of the arc on both sides of the partition plate.

5. The method for adjusting the circumferential clearance of a thrust bearing in a marine gearbox according to claim 1, characterized in that: By adopting the reference transfer method, a reference measuring block is fixed on the gearbox body corresponding to the position of the thrust flange and the thrust bearing on the output shaft, and the measuring reference surface is transferred to the measuring surface parallel to it on the reference measuring block.

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