A method for assembling a double helical planetary transmission reduction structure
Patent Information
- Application Number
- CN202610580551.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-29
- Publication Date
- 2026-10-20
Smart Images
Figure FT_1 
Figure FT_2 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of mechanical transmission assembly technology, specifically relating to an assembly method for a herringbone planetary transmission reduction structure, which is suitable for test piece assembly scenarios requiring high load uniformity. Background Technology
[0002] Currently, planetary gear drives typically include three transmission forms: spur gear, helical gear, and herringbone gear. Herringbone planetary gear drives, using a pair of symmetrically arranged helical gears with opposite helical directions, can further improve the load-bearing capacity of the reduction mechanism. Simultaneously, they counteract the axial load acting on the bearings in helical gear drives, simplifying the axial support requirements of the gears. This allows the gears to achieve error compensation and load distribution through their own force balance during transmission, significantly improving transmission smoothness and resulting in better noise characteristics. However, in practical engineering applications, the presence of manufacturing and assembly errors can easily lead to uneven meshing contact between the planetary gears and the sun gear and ring gear, resulting in force imbalance among the planetary gears. Furthermore, due to accumulated errors and the presence of assembly chains, after assembling multiple planetary gears, the left and right tooth surfaces of each gear have different centering errors and cannot be within a suitable height difference range, causing uneven force on the evenly distributed left and right tooth surfaces of the planetary gears. These uneven loads can lead to premature wear during product use, generating vibration, impact, and noise, severely reducing the working performance, service life, and reliability of the herringbone planetary gear reduction structure. Traditional assembly methods rely heavily on experience-based adjustments, lacking systematic error matching and dynamic compensation measures, resulting in poor assembly stability and difficulty in meeting the product's requirements for transmission stability. Therefore, achieving uniform force distribution among the planetary gears and between the left and right teeth of the planetary gears in the herringbone planetary transmission reducer structure, and thus achieving good load-sharing performance, is a crucial issue that needs to be addressed in the design of the herringbone planetary transmission reducer structure. Summary of the Invention
[0003] Purpose of the invention: To provide an assembly method for a herringbone planetary transmission reduction structure, particularly suitable for herringbone planetary transmission reduction structures with a large number of planetary gears, improper control of planetary gear manufacturing errors, and complex planetary gear installation and positioning. This method effectively achieves load sharing compensation in the herringbone planetary reduction structure, improving the working performance, service life, and reliability of the gear transmission.
[0004] Technical solution: A method for assembling a herringbone-tooth planetary transmission reduction structure, wherein the planetary transmission reduction structure is as follows: Figure 1 Composed of sun gears 1 and n P The system consists of 15 components: 2. Planetary gear, 3. First internal gear ring, 4. Second internal gear ring, 5. Planetary gear carrier, 6. Planetary gear mounting plate, 7. Planetary gear pin, 8. Planetary gear bearing, 9. Lock nut, 10. Connecting bolt, 11. Spline sleeve, 12. Pressure plate, 13. Spacer sleeve, 14. Positioning bushing, and 15. Screws. The specific assembly steps are as follows: Step 1: Based on the structure of the herringbone planetary transmission reducer, establish the calculation formula for the adjusting shim size chain and generate a data set list; Step 2: Based on the data group list, complete the parts processing and data measurement to form an actual database; Step 3: Based on the actual database, group the planetary gears, sun gear, and ring gear, and perform gear matching based on the grouping to form an assembly unit; Step 4: Assemble each assembly unit separately, calculate the thickness of the adjusting shim corresponding to each planetary gear according to the dimensional chain calculation formula, and install the adjusting shim according to the calculated adjusting shim thickness to pre-position each planetary gear axially. Step 5: Perform tooth contact imprint detection to determine whether the pre-positioned planetary gears meet the requirements. If they do, proceed to the next step; otherwise, return to Step 4 to recheck and fine-tune the adjustment shims. Step Six: Perform floating compensation assembly; Step 7: Conduct a loading test on each planetary gear to verify whether the load distribution coefficient meets the requirements. If it does, proceed to the next step; otherwise, return to step 4 to readjust the thickness of the adjustment pad. Step 8: Solidify, label, and record the assembly status.
[0005] Furthermore, in step one, the specific process is as follows: 1a. Determine the reference surface. Based on the herringbone gear planetary transmission reduction structure, determine the axial positioning reference surface of the planetary gears as the axial limiting surface for the bearing installation of each planetary gear. P Each planetary gear is limited by this surface; such as Figure 3 The planetary carrier mounting disk n shown P The inner ring mounting surface of the planetary gear bearing is formed in one piece, and its flatness is generally required to be controlled within 0.01mm.
[0006] 1b, Determine the positioning dimension H in the i-th planetary gear pair. i The value of i ranges from 1 to n. P Positioning dimension H i This represents the distance between the centerline of the left and right helical teeth of each planetary gear and the reference plane; for n P Planetary transmissions composed of planetary gears have a dimension of n. P indivual.
[0007] 1c, Create a dimension chain calculation formula according to mechanical design principles. All dimensions involved in the dimension chain calculation formula are dimensions from the data group list. 1d, the data set list includes the following dimensions: The alignment error of planetary gears, including the direction of the error; The width of the inner and outer rings of the planetary gear bearing and the height difference between the inner and outer rings in the direction of force; Axial runout and radial clearance of planetary gear bearings; The distance between the locating surface of each planetary gear bearing and the centerline; The tooth thickness of each planetary gear and the sun gear; Tooth direction error of each planetary gear and sun gear; The positional accuracy of each pin hole on the planetary gear carrier.
[0008] Furthermore, in step two, the herringbone tooth surfaces of the sun gear and planetary gears are measured to obtain the tooth thickness deviation at the midpoint of the tooth width, the tooth direction error along the tooth width direction, and the centering error relative to the same measurement surface for each gear; the axial dimensions of the planetary gears and planetary gear bearings are measured to obtain the distance between the planetary gear positioning surface and the center line, the inner and outer ring widths of the planetary gear bearings, and the axial runout; the position accuracy of the planetary gear carrier measuring pin hole is measured. After all data measurements are completed, an actual database containing part numbers and error parameters is established.
[0009] The measurement methods used, such as coordinate measuring machines, gear measuring machines, micrometers, or height gauges, should have a measurement accuracy higher than 0.001 mm.
[0010] Furthermore, in step three, the grouping principles are as follows: Planetary gears are classified into three levels according to the tooth thickness deviation range: negative deviation group, positive deviation group, and neutral group. The neutral group is ±15% of the deviation range, the negative deviation is -50% to -15% of the deviation range, and the positive deviation is +15% to +50% of the deviation range. The planetary gears are further grouped according to the tooth direction error in the tooth thickness grouping state, defining the left and right ends, which should correspond to the sun gear according to the meshing direction; if the left end is thicker and the right end is thinner in the tooth width direction, it is divided into the left-biased group, and if the left end is thinner and the right end is thicker, it is divided into the right-biased group. Sun gears are grouped according to tooth direction error, defining left and right ends. If the left end is thicker and the right end is thinner in the tooth width direction, it is divided into the left-biased group; if the left end is thinner and the right end is thicker, it is divided into the right-biased group. The assembly unit matching principle is as follows: Choose n P All planetary gears, all of which are left-biased, are matched with the right-biased sun gear, and n P Each planetary gear has either a negative deviation, a positive deviation, or a neutral deviation; Choose n P All planetary gears, all of which are right-biased, are matched with the left-biased sun gear, and n P Each planetary gear has either a negative deviation, a positive deviation, or a neutral deviation.
[0011] Further, in step four, the positioning dimensions of each planetary gear within the assembly unit are calculated, and the maximum value is taken as the reference for this assembly unit. The difference between the positioning dimensions of the remaining planetary gears and the reference is calculated, and the corresponding difference is used as the adjustment shim thickness for the remaining planetary gears. The adjustment shim with the difference thickness is installed between the corresponding planetary gear bearing and the planetary carrier mounting plate. After installation, the center lines of the upper and lower helical teeth of each planetary gear will be within the same horizontal deviation.
[0012] Furthermore, in step five, the contact imprint detection is performed individually for each planetary gear, as follows: After assembling the planetary gears and the sun gear, without assembling the gear ring, apply red lead powder to the upper and lower tooth surfaces of the planetary gear being tested, evenly distributed in at least 3 places around the circumference, with at least 3 teeth at each place. Rotate the sun gear 3-5 times and observe the imprints on the planetary gear teeth coated with red lead powder; If the area of the imprint on the upper tooth surface exceeds 55% and that on the lower end is less than 45%, then increase the thickness of the adjusting shim for the corresponding planetary gear; otherwise, decrease the thickness of the adjusting shim for the corresponding planetary gear. Repeat the above operation until n P All planetary gear imprints were inspected and found to meet the requirement that the ratio of the imprint areas on both sides should not exceed 45:55. If the thickness of the adjusting pad varies beyond ±0.05mm, the measurement data and dimensional chain calculation results should be rechecked.
[0013] Furthermore, in step six, a planetary gear bearing is installed between the planetary gear and the planetary carrier pin. The inner bore of the planetary gear mates with the outer ring of the planetary gear bearing, selecting either a transition or interference fit. The inner ring of the bearing mates with the outer diameter of the planetary carrier pin, selecting either a transition or interference fit. Depending on the type of bearing selected, the radial and axial clearances are controlled. The radial clearance after assembly is not less than the positional error of the planetary carrier pin. The axial clearance after assembly is not less than the alignment error of the planetary gear, sun gear, and gear ring.
[0014] Furthermore, in step seven, the assembled planetary gears are meshed with the sun gear and the ring gear, and a 30% rated load is applied to the input end. The force value of each planetary gear is detected by installing a torque sensor at the same position at the output end of each planetary gear shaft. Calculate n P The average force on each planetary gear and the maximum force on each planetary gear; If there exists a difference between the maximum force on the planetary gear and the average force, and n PIf the ratio of the average force on each planetary gear exceeds the design allowable value of the herringbone planetary transmission reducer, a quality re-inspection of the planetary gears, sun gear, ring gear, and planetary carrier assembly is required. The planetary gears with excessive values should be disassembled, and the planetary gear tooth profile / direction, cumulative pitch error, and radial / end face runout should be remeasured. The tooth surface accuracy and coaxiality of the sun gear and ring gear should be checked. The position of the planetary carrier pins and bearing mounting holes should be confirmed. The uniformity of the preload of the planetary gear shaft end nuts should be checked. Positional deviations can be compensated by grinding the planetary carrier pins and fine-tuning the bearing preload, or by replacing parts with large deviations to compensate for accumulated errors. After adjustment, reassemble until n P The difference between the maximum force on each planetary gear and the average force, and n P The ratio of the average force on each planetary gear meets the design allowable value for this herringbone planetary transmission reducer.
[0015] Furthermore, in step eight, the planetary gears are marked with positions, defined as 1, 2...n. P Record the location and thickness of the final adjustment shim according to the part, and record the assembly position and batch information of the sun gear, planetary gears, planetary gear bearings, and planetary gear carrier; mark the error matching group and conversion parameters or codes on the non-working surface of the test piece.
[0016] Furthermore, the torque sensor is installed at the shaft extension end on the planetary carrier side.
[0017] Beneficial effects: This invention proposes an assembly method for a herringbone planetary transmission reduction structure, providing a novel approach to achieving high load uniformity in herringbone planetary transmissions. It compensates for errors through error grouping and matching, achieves dynamic balance through axial adjustment and radial floating, and ensures assembly accuracy through load verification. This method compensates for uneven loads caused by manufacturing and assembly errors. Compared to traditional methods, the method described in this invention reduces the uneven load coefficient of the planetary gears from over 1.25 to below 1.1; improves contact imprint uniformity by 40%; and achieves test data repeatability (standard deviation) ≤3%. This more accurately reflects transmission performance. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2This is a flowchart of the assembly method of a herringbone-tooth planetary transmission reduction structure according to the present invention; Figure 3 This is a schematic diagram of the reference surface of the planetary carrier mounting disk as described in a specific implementation of the present invention; Figure 4 This is a schematic diagram of the positioning dimension Hi as described in a specific implementation of the present invention;
[0020] 1. Sun gear, 2. Planetary gear, 3. First internal gear ring, 4. Second internal gear ring, 5. Planetary gear carrier, 6. Planetary gear mounting plate, 7. Planetary gear pin, 8. Planetary gear bearing, 9. Lock nut, 10. Connecting bolt, 11. Spline sleeve, 12. Pressure plate, 13. Spacer sleeve, 14. Positioning bushing, 15. Screw. Detailed Implementation
[0021] 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 embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0022] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.
[0023] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.
[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.
[0025] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0027] A method for assembling a herringbone-tooth planetary transmission reduction structure, wherein the planetary transmission reduction structure is as follows: Figure 1 Composed of sun gears 1 and n P The system comprises a planetary gear 2, a first internal gear ring 3, a second internal gear ring 4, a planetary gear carrier 5, a planetary gear mounting plate 6, a planetary gear pin 7, a planetary gear bearing 8, a lock nut 9, a connecting bolt 10, a spline sleeve 11, a pressure plate 12, a spacer sleeve 13, a positioning bushing 14, and screws 15. A detailed flowchart of the assembly method for this herringbone planetary transmission reduction structure is shown below. Figure 2 .
[0028] Step 1: Based on the structure of the herringbone planetary transmission reducer, establish the adjustment shim calculation dimension chain, and propose the dimensions and errors related to each component, the dimension chain, and the load sharing, forming a data set list; Step 2: Based on the data list, complete the part preprocessing and data measurement to form an actual database; Step 3: Based on the established database, group the planetary gears, sun gear, and ring gear, and perform gear matching based on the grouping to form an assembly unit; Step 4: Perform assembly. Based on the dimensional chain calculation requirements, perform dimensional chain calculations according to the actual dimensions, determine the thickness of the adjusting shim, and pre-position it in a suitable position to complete the axial pre-positioning. Step 5: Perform tooth contact imprint detection and determine whether the pre-adjustment meets the requirements according to the judgment criteria. If it does not meet the requirements, return to step 4 to recheck and fine-tune the adjustment shim until the contact detection meets the requirements.
[0029] Step Six: If the requirements are met, continue with the floating compensation assembly to complete the assembly.
[0030] Step 7: Under the test conditions, conduct a loading test on each planetary gear to verify whether the load distribution coefficient meets the requirements. If it does not meet the requirements, return to step 4 for readjustment. Step 8: If the requirements are met, the status will be solidified, identified, and recorded.
[0031] Specifically as follows: 1) Establishing a dimension chain and extracting data sets can be done as follows: (a) First, determine the reference surface. Based on the herringbone planetary reducer structure diagram, determine the axial positioning reference surface of the planetary gears. This surface is generally the axial limiting surface for the installation of each planetary gear bearing. P Each planetary gear is limited by this surface, such as Figure 3 The planetary carrier mounting disk n shown P The inner ring mounting surface of the planetary gear bearing is formed in one piece, and its flatness is generally required to be controlled within 0.01mm.
[0032] (b) Determine n again P Positioning dimension H in a planetary gear pair i Location such as Figure 4 As shown. This dimension represents the distance between the centerline of the left and right helical teeth of each planetary gear and the reference plane, for n P Planetary transmissions composed of planetary gears have a dimension of n. P One, size H i In this case, i is from 1 to n P .
[0033] (c) Then establish the dimension chain. According to the dimension chain calculation principle in mechanical design principles, determine the closed loop based on the herringbone planetary reducer structure diagram, find the dimensions of each relevant component in the entire loop, determine the dimension increase and decrease attributes, and list the calculation formula according to Hi being equal to the sum of all increasing loops minus the sum of all decreasing loops. The dimension chain creation is completed. All dimensions involved in the dimension chain calculation are listed in the data group list in (d).
[0034] (d) Finally, a list of data groups is formed. The data in the data list includes, but is not limited to, the following dimensions: The alignment error of planetary gears, including the direction of the error; The width of the inner and outer rings of the planetary gear bearing and the height difference between the inner and outer rings in the direction of force; Axial runout and radial clearance of planetary gear bearings; The distance between the locating surface of each planetary gear bearing and the centerline; The tooth thickness of each planetary gear and the sun gear; Tooth direction error of each planetary gear and sun gear; The positional accuracy of each pin hole on the planetary gear carrier.
[0035] 2) Parts pretreatment and data measurement Using effective measurement methods, the herringbone tooth surfaces of the sun gear and planetary gears are measured to obtain the tooth thickness deviation at the midpoint of the tooth width, the tooth direction error along the tooth width, and the centering error relative to the same measurement surface for each gear. The axial dimensions of the planetary gears and planetary gear bearings are measured to obtain the distance between the planetary gear locating surface and the centerline, the inner and outer ring widths of the planetary gear bearings, and the axial runout. The position accuracy of the pin holes in the planetary gear carrier is measured. The measurement methods used, such as coordinate measuring machines, gear measuring machines, micrometers, or height gauges, should have an accuracy higher than 0.001 mm. After all data measurements are completed, a database containing part numbers and error parameters is established.
[0036] 3) Error grouping and pre-installation matching The parts in the database are classified and matched as follows: (a) Planetary gears are divided into three levels according to the tooth thickness deviation range: negative deviation group, positive deviation group and neutral group. The neutral group takes ±15% of the deviation range, the negative deviation takes -50% to -15% of the deviation range, and the positive deviation takes +15% to +50% of the deviation range.
[0037] (b) The sun gear is grouped according to the tooth direction error, and the left and right ends are defined. If the left end is thicker and the right end is thinner in the tooth width direction, it is the left-biased group. Conversely, if the left end is thinner and the right end is thicker, it is the right-biased group. (c) The planetary gears, after being grouped by tooth thickness, are further subdivided according to tooth direction error, defining left and right ends, which should correspond to the sun gear in the meshing direction. If the left end is thicker and the right end is thinner in the tooth width direction, it is a left-biased group. Conversely, if the left end is thinner and the right end is thicker, it is a right-biased group. (d) The sun gear is matched with the planetary gears, and n is selected. P Each planetary gear has a negative or positive deviation, and is neutral. The tooth direction error is either left-biased or right-biased. The left-biased planetary gear is matched with the right-biased sun gear, and vice versa, to cancel out the errors. This results in multiple matched assembly groups.
[0038] 4) Axial pre-adjustment positioning Based on the dimension chain calculation formula established in 1), and according to the actual dimensions measured in 2), calculate the positioning dimension H of each planetary gear in each assembly group. i Take the maximum value as the reference for this assembly group, calculate the difference between the positioning dimensions of the remaining planetary gears and the reference, and this difference is the theoretical thickness of the adjustment shim to be added to the remaining planetary gears. Install the adjustment shim with the difference thickness between the corresponding planetary gear bearing and the planet carrier mounting plate. After installation, the center lines of the upper and lower helical teeth of each planetary gear will be within the same horizontal deviation.
[0039] 5) Tooth surface contact detection (modified) The tooth surface contact test requires individual testing for each planetary gear. The method is as follows: Assemble all planetary gears according to the matching and adjustment settings described above. After installing the sun gear, without assembling the gear ring, apply red lead powder to the upper and lower tooth surfaces of one planetary gear, distributing it approximately evenly around the circumference at at least three points, with at least three teeth at each point. After assembly, rotate the sun gear 3-5 times and observe the imprints on the planetary gear tooth surfaces coated with red lead powder. If the imprint area on the upper tooth surface exceeds 55% and the lower tooth surface is less than 45%, increase the thickness of the pre-set adjustment shim. Conversely, if the imprint area on the upper tooth surface is less than 55% and the lower tooth surface exceeds 45%, decrease the thickness of the pre-set adjustment shim. Repeat this operation until the planetary gear imprint inspection shows that the ratio of the imprint areas on both sides does not exceed 45:55. Each of the np planetary gears is checked for contact marks. This process is repeated until all np planetary gears have a contact mark area ratio of no more than 45:55 on both sides. The thickness of the adjusting shim should generally be within ±0.05mm. If it exceeds this range, the dimensional chain and measurement data must be rechecked for accuracy.
[0040] 6) Floating compensation assembly Planetary gear bearings are installed between the planetary gears and the planetary carrier pins. Typically, the inner bore of the planetary gear mates with the outer ring of the planetary gear bearing, using either a transition or interference fit. The inner ring of the bearing mates with the outer diameter of the planetary carrier pin, also using either a transition or interference fit; an interference fit is recommended. Depending on the type of bearing selected, radial and axial clearances must be controlled. The radial clearance after assembly should not be less than the positional error of the planetary carrier pin. The axial clearance after assembly should not be less than the alignment error of the planetary gear, sun gear, and ring gear.
[0041] 7) Overall meshing verification and adjustment The assembled planetary gear train is meshed with the sun gear and ring gear. 30% of the rated load is applied to the input end. The force value of each planet gear is detected by installing a torque sensor at the output end of each planet gear shaft. The torque sensors are preferably installed at the shaft extension end on the planet carrier side. P Each planetary gear corresponds to n P Each sensor should be positioned at the exact same location. Collect n data. P Calculate n based on data from each sensor under the same load and time period. P The average force on each planetary gear and the maximum force on each planetary gear. If the difference between the maximum force of one or more planetary gears and the average force is less than n... PIf the average force ratio of the planetary gears exceeds the design allowable value of the herringbone planetary transmission reducer, a quality re-inspection of the planetary gears, sun gear, ring gear, and planet carrier assembly is required. The planetary gears with excessive values should be disassembled, and the tooth profile / direction, cumulative pitch error, and radial / end face runout of the planetary gears should be remeasured. The tooth surface accuracy and coaxiality of the sun gear and ring gear should be checked. The position of the planetary carrier pins and the bearing mounting holes should be confirmed. The preload of the planetary gear shaft end nuts should be checked for uniformity. If there is a deviation from the design allowable unit or a large deviation, such as a large deviation in the position of the planetary carrier pins, the position deviation can be compensated by grinding the planetary carrier pins, fine-tuning the bearing preload, or by replacing the parts with larger deviations to compensate for the accumulated error. After adjustment, reassemble according to the above steps until n P The difference between the maximum force on each planetary gear and the average force on each planetary gear, and n P The ratio of the average force on each planetary gear meets the design allowable value for this herringbone planetary transmission reducer.
[0042] 8) Curing and labeling Position markings are applied to the planetary gears, defining 1, 2, ..., n. P Record the location and thickness of the final adjustment shims by part, and record the assembly position and batch information of the sun gear, planetary gears, planetary gear bearings, and planetary gear carrier. Mark the error matching group and conversion parameters or codes on the non-working surface of the test piece.
[0043] Example According to this method, Figure 1 The herringbone planetary transmission reduction structure shown has undergone assembly adjustments to compensate for its load-sharing characteristics. Specific implementation steps are as follows: 1) Establish a dimension chain and extract data sets. (a) According to the herringbone-tooth planetary deceleration structure diagram ( Figure 1 The axial positioning reference surface of the planetary gears is determined to be the mounting surface of the inner rings of the five planetary gear bearings on the planet carrier mounting plate. Figure 3 ).
[0044] (b) Determine n P The positioning dimension H in a planetary gear pair i i is from 1 to n P Location such as Figure 4 As shown.
[0045] (c) Establish dimension H based on the structural diagram of the herringbone planetary reducer. i The formula for calculating the dimensions is: H i =A-B+C+DE In the formula: A is the width of the inner ring of the planetary gear bearing; B is the height difference between the inner ring end face and the outer ring of the planetary gear; C represents the thickness of the bearing retaining ring; D is the distance from the upper end face of the retaining ring groove to the end face of the planetary gear; E is the distance from the end face of the planetary gear to the actual center line of the left and right teeth of the herringbone gear.
[0046] (d) Form a list of data sets, including the following dimensions: The alignment error S of a planetary gear is positive when pointing upwards and negative when pointing downwards; The inner ring width A of the planetary gear bearing; The height difference B between the inner and outer rings of a planetary gear bearing is positive for the inner ring height. Thickness C of the bearing retaining ring at the outer ring of the planetary gear bearing; The distance D from the upper end face of the retaining ring groove of the planetary gear to the end face of the planetary gear; E is the actual distance E from the end face of the planetary gear to the center line of the left and right teeth of the herringbone gear. Axial displacement F and radial clearance G of planetary gear bearings; Planetary gear tooth thickness J; Sun gear tooth thickness K; Planetary gear tooth direction error L Sun gear tooth direction error M; Planetary gear carrier n p个 The positional accuracy of the pin hole Q I .
[0047] 2) Parts pretreatment and data measurement A gear measuring machine was used to measure the herringbone tooth surfaces of the sun gear and planetary gears, obtaining the tooth thickness deviation at the midpoint of the tooth width, the tooth direction error along the tooth width, and the centering error relative to the same measuring surface for each gear. A micrometer was used to measure the planetary gears and planetary gear bearings, obtaining the distance between the planetary gear end face and the centerline, and the inner and outer ring widths of the planetary gear bearings. A coordinate measuring machine was used to measure the pin hole position accuracy of the planetary gear carrier. After all data measurements were completed, a database containing part numbers and error parameters was established. For example, the planetary gear database is shown in the table below, and must contain at least the information shown in the table.
[0048]
[0049] 3) Error grouping and pre-installation matching The parts in the database are classified and matched as follows: (a) Planetary gears are grouped according to tooth thickness deviation. The tooth thickness is 5.85-0.144-0.169, and the deviation is 0.025mm. The neutral group has a value of 5.85-0.15275-0.16025, the negative deviation group has a value of 5.85-0.16025-0.169, and the positive deviation group has a value of 5.85-0.144-0.15275.
[0050] (b) The sun gear is grouped according to tooth direction error, and the left end, right end, and left offset groups are defined; (c) The planetary gears are further subdivided into groups based on tooth direction error in the tooth thickness grouping state, defining left end, right end, and right offset groups; (d) The sun gear is matched with the planetary gears. Five planetary gears are selected, all of which have negative deviations of 5.85-0.16025-0.169, and the tooth direction errors are all right-biased groups, while the sun gear is left-biased group, thus canceling out the errors.
[0051] 4) Axial pre-adjustment positioning Based on the dimensional chain calculation formula established in 1), and according to the actual dimensions measured in 2), calculate the positioning dimension H of each planetary gear. i The dimensions are as follows: H1 is 47.36mm, H2 is 47.23mm, H3 is 47.39mm, H4 is 47.17mm, and H5 is 47.28mm. Taking the maximum value H3 as the reference, the differences between the positioning dimensions of the remaining planetary gears and the reference are calculated to be 0.03mm, 0.16mm, 0.22mm, and 0.11mm, respectively. The thicknesses of the adjusting shims at planetary gears #1, #2, #4, and #5 are determined to be 0.03mm, 0.16mm, 0.22mm, and 0.11mm, respectively. The adjusting shims are then installed between the lower end face of the inner ring of the planetary gear bearing and the reference surface of the planetary carrier mounting plate.
[0052] 5) Tooth surface contact detection Apply red lead powder to the upper and lower tooth surfaces of a single planetary gear, approximately evenly distributed in three locations around the circumference, with three teeth at each location. After assembly, rotate the sun gear 3-5 times and observe the red lead powder imprints on the tooth surfaces. If the imprint area on the upper tooth surface exceeds 55% and that on the lower tooth surface is less than 45%, increase the thickness of the pre-set adjustment shim. Conversely, if the imprint area on the upper tooth surface is less than 55% and that on the lower tooth surface exceeds 45%, decrease the thickness of the pre-set adjustment shim. Repeat the operation of applying red lead powder to each planetary gear and performing tooth surface contact testing until all five planetary gear imprints meet the requirement that the ratio of the imprint areas on both sides is 45:55.
[0053] 6) Floating compensation assembly A planetary gear bearing is installed between the planetary gear and the planetary carrier pin. The inner bore of the planetary gear and the outer ring of the planetary gear bearing are selected for a transition fit. The inner ring of the bearing is interference-fitted with the outer diameter of the planetary carrier pin. At each selected location, the radial clearance G of the planetary gear bearing is greater than the positional error Q of the planetary carrier pin. The axial clearance F is greater than the alignment error S of the planetary gear.
[0054] 7) Overall meshing verification and adjustment The assembled planetary gear train was meshed with the sun gear and ring gear. A 30% rated load was applied to the input end. Torque sensors were installed on each planetary gear to detect the force values on each planetary gear, which were 35636 N, 37421 N, 35569 N, 36731 N, and 36663 N, respectively. The difference between the maximum force (37421 N) and the minimum force (35569 N) was 1852 N, accounting for 5% of the average value, which met the requirements. The next step was then performed.
[0055] 8) Curing and labeling Mark the positions of the planetary gears, defining positions 1, 2, 3, 4, and 5. Mark the non-working visible surfaces of the planetary gear carrier with numbers 1#, 2#, 3#, 4#, and 5#. Record the thickness of the adjusting shims at each marked location and the batch information of the sun gear, planetary gears, and planetary gear bearings. See the table below for an example.
[0056]
[0057] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.
Claims
1. An assembly method for a herringbone-tooth planetary transmission reduction structure, characterized in that: The steps are as follows: Step 1: Based on the structure of the herringbone planetary transmission reducer, establish the calculation formula for the adjusting shim size chain and generate a data set list; Step 2: Based on the data set list, complete the part preprocessing and data measurement to form an actual database; Step 3: Based on the actual database, group the planetary gears, sun gear, and ring gear, and perform gear matching based on the grouping to form an assembly unit; Step 4: Assemble each assembly unit separately, calculate the thickness of the adjusting shim corresponding to each planetary gear according to the dimensional chain calculation formula, and install the adjusting shim according to the calculated adjusting shim thickness to pre-position each planetary gear axially. Step 5: Perform tooth contact imprint detection to determine whether the pre-positioned planetary gears meet the requirements. If they do, proceed to the next step; otherwise, return to Step 4 to recheck and fine-tune the adjustment shims. Step Six: Perform floating compensation assembly; Step 7: Conduct a loading test on each planetary gear to verify whether the load distribution coefficient meets the requirements. If it does, proceed to the next step; otherwise, return to step 4 to readjust the thickness of the adjustment pad. Step 8: Solidify, label, and record the assembly status.
2. The method according to claim 1, characterized in that: Step one, the specific process is as follows: 1a. Determine the reference surface. Based on the herringbone planetary transmission reduction structure, determine the axial positioning reference surface of the planetary gears as the axial limiting surface for the bearing installation of each planetary gear. P Each planetary gear is limited by this surface; 1b, Determine the positioning dimension H in the i-th planetary gear pair. i The value of i ranges from 1 to n. P Positioning dimension H i This represents the distance between the centerline of the left and right helical teeth of each planetary gear and the reference plane. 1c, Create a dimension chain calculation formula according to mechanical design principles. All dimensions involved in the dimension chain calculation formula are dimensions from the data group list. 1d, the data set list includes the following dimensions: The alignment error of planetary gears, including the direction of the error; The width of the inner and outer rings of the planetary gear bearing and the height difference between the inner and outer rings in the direction of force; Axial runout and radial clearance of planetary gear bearings; The distance between the locating surface of each planetary gear bearing and the centerline; The tooth thickness of each planetary gear and the sun gear; Tooth direction error of each planetary gear and sun gear; The positional accuracy of each pin hole on the planetary gear carrier.
3. The method according to claim 2, characterized in that: In step two, the herringbone tooth surfaces of the sun gear and planetary gears are measured to obtain the tooth thickness deviation at the midpoint of the tooth width, the tooth direction error along the tooth width, and the centering error relative to the same measurement surface for each gear; the axial dimensions of the planetary gears and planetary gear bearings are measured to obtain the distance between the planetary gear positioning surface and the center line, the inner and outer ring widths of the planetary gear bearings, and the axial runout; the position accuracy of the planetary gear carrier measuring pin hole is measured. After all data measurements are completed, an actual database containing part numbers and error parameters is established.
4. The method according to claim 3, characterized in that: In step three, the grouping principles are as follows: Planetary gears are classified into three levels according to the tooth thickness deviation range: negative deviation group, positive deviation group, and neutral group. The neutral group is ±15% of the deviation range, the negative deviation is -50% to -15% of the deviation range, and the positive deviation is +15% to +50% of the deviation range. The planetary gears are further grouped according to the tooth direction error in the tooth thickness grouping state, defining the left and right ends, which should correspond to the sun gear according to the meshing direction; if the left end is thicker and the right end is thinner in the tooth width direction, it is divided into the left-biased group, and if the left end is thinner and the right end is thicker, it is divided into the right-biased group. Sun gears are grouped according to tooth direction error, defining left and right ends. If the left end is thicker and the right end is thinner in the tooth width direction, it is divided into the left-biased group; if the left end is thinner and the right end is thicker, it is divided into the right-biased group. The assembly unit matching principle is as follows: Choose n P All planetary gears, all of which are left-biased, are matched with the right-biased sun gear, and n P Each planetary gear has either a negative deviation, a positive deviation, or a neutral deviation; Choose n P All planetary gears, all of which are right-biased, are matched with the left-biased sun gear, and n P Each planetary gear has either a negative deviation, a positive deviation, or a neutral deviation.
5. The method according to claim 4, characterized in that: In step four, the positioning dimensions of each planetary gear in the assembly unit are calculated, and the maximum value is taken as the reference of this assembly unit. The difference between the positioning dimensions of the remaining planetary gears and the reference is calculated, and the corresponding difference is used as the adjustment shim thickness of the remaining planetary gears.
6. The method according to claim 5, characterized in that: In step five, contact imprint detection is performed individually for each planetary gear, as follows: After assembling the planetary gears and the sun gear, without assembling the gear ring, apply red lead powder to the upper and lower tooth surfaces of the planetary gear being tested, evenly distributed in at least 3 places around the circumference, with at least 3 teeth at each place. Rotate the sun gear 3-5 times and observe the imprints on the planetary gear teeth coated with red lead powder; If the area of the imprint on the upper tooth surface exceeds 55% and that on the lower end is less than 45%, then increase the thickness of the adjusting shim for the corresponding planetary gear; otherwise, decrease the thickness of the adjusting shim for the corresponding planetary gear. Repeat the above operation until n P All planetary gear imprints were inspected and found to meet the requirement that the ratio of the imprint areas on both sides should not exceed 45:
55. If the thickness of the adjusting pad varies beyond ±0.05mm, the measurement data and dimensional chain calculation results should be rechecked.
7. The method according to claim 6, characterized in that: In step six, a planetary gear bearing is installed between the planetary gear and the planetary carrier pin. The inner bore of the planetary gear mates with the outer ring of the planetary gear bearing, selecting either a transition or interference fit. The inner ring of the bearing mates with the outer diameter of the planetary carrier pin, selecting either a transition or interference fit. Depending on the type of bearing selected, the radial and axial clearances are controlled. The radial clearance after assembly is not less than the positional error of the planetary carrier pin. The axial clearance after assembly is not less than the alignment error of the planetary gear, sun gear, and gear ring.
8. The method according to claim 7, characterized in that: In step seven, the assembled planetary gears are meshed with the sun gear and the ring gear. A 30% rated load is applied to the input end. The force value of each planetary gear is detected by installing a torque sensor at the same position at the output end of each planetary gear shaft. Calculate n P The average force on each planetary gear and the maximum force on each planetary gear; If there exists a difference between the maximum force on the planetary gear and the average force, and n P If the ratio of the average force on each planetary gear exceeds the design allowable value of the herringbone planetary transmission reducer, a quality re-inspection of the planetary gears, sun gear, ring gear, and planetary carrier assembly is required. The planetary gears with excessive values should be disassembled, and the planetary gear tooth profile / direction, cumulative pitch error, and radial / end face runout should be remeasured. The tooth surface accuracy and coaxiality of the sun gear and ring gear should be checked. The position of the planetary carrier pins and bearing mounting holes should be confirmed. The uniformity of the preload of the planetary gear shaft end nuts should be checked. Positional deviations can be compensated by grinding the planetary carrier pins and fine-tuning the bearing preload, or by replacing parts with large deviations to compensate for accumulated errors. After adjustment, reassemble until n P The difference between the maximum force on each planetary gear and the average force, and n P The ratio of the average force on each planetary gear meets the design allowable value for this herringbone planetary transmission reducer.
9. The method according to claim 8, characterized in that: In step eight, the planetary gears are marked with positions, defined as 1, 2, ..., n. P Record the location and thickness of the final adjustment shim according to the part, and record the assembly position and batch information of the sun gear, planetary gears, planetary gear bearings, and planetary gear carrier; mark the error matching group and conversion parameters or codes on the non-working surface of the test piece.
10. The method according to claim 9, characterized in that: The torque sensor is installed at the shaft extension end on the planetary carrier side.