Assembly method of reduction gearbox

Abstract

The present invention discloses an assembly method for a speed reducer. After the planetary gear train assembly is independently installed, at least two jacking tools capable of jacking up the ring gear and the fixed sleeve in the planetary gear train are installed on the planet carrier of the planetary gear train assembly. The telescopic end of the jacking tool that can change its length abuts against the bottom of the ring gear. In this way, the height of the ring gear and the relative inclination angle between the planet gear and the ring gear can be adjusted by at least two jacking tools. Then, the planetary gear train assembly equipped with the jacking tools is hoisted onto the thrust head assembly that has been assembled. In this way, the assembly efficiency of the speed reducer is further improved by means of split assembly.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power, and particularly to an assembly method of a reduction gearbox. Background Art

[0002] In a reduction gearbox, how to ensure the coaxiality between various components during the installation process of the reduction gearbox has always affected the assembly efficiency and service life of the reduction gearbox.

[0003] The patent document with the publication number CN20113Y discloses a vertical herringbone gear planetary reducer, which includes an input coupling, a planetary gear train, a housing, radial bearings, a thrust bearing assembly, and an output expansion sleeve mechanism, wherein: the teeth on the sun gear, the carrier gear, and the internal gear ring in the planetary gear train are all herringbone teeth; an input coupling is provided at the upper end of the upright sun gear shaft in the planetary gear train; the internal gear ring in the planetary gear train is fixed by a floating gear ring; the planetary carrier in the planetary gear train is connected to a support frame, and the support frame is positioned in the cover of the housing by radial bearings; the planetary carrier in the planetary gear train is connected to the output shaft by bolts and pins, and the output shaft and the sun gear shaft are on the same axis; the output expansion sleeve mechanism in the output shaft is supported on the reducer bottom plate by the thrust bearing assembly and the radial bearings.

[0004] Since the planet gears and the internal gear ring in the planetary gear train in the prior art can move up and down, during the installation process of such a reducer, usually, after the lower gear ring is sleeved on the output shaft, the planetary carrier is fixed on the top of the output shaft, and then the lower gear ring is lifted; such an installation process is cumbersome and affects the positioning accuracy between various components in the reduction gearbox. Summary of the Invention

[0005] In order to solve the problems of cumbersome assembly process and low assembly efficiency of the reduction gearbox in the prior art; the purpose of the present invention is to provide an assembly method of a reduction gearbox, in which after the planetary gear train assembly is independently installed, at least two jacking tools capable of jacking up the gear ring and the fixed sleeve in the planetary gear train are installed on the planetary carrier of the planetary gear train assembly, and then the planetary gear train assembly installed with the jacking tools is hoisted onto the assembled thrust head assembly, so that two important components of the reduction gearbox can be independently installed, effectively improving the assembly accuracy and assembly efficiency of the reduction gearbox.

[0006] To achieve the above object, the present invention adopts the following technical solutions: An assembly method for a speed reducer, the speed reducer comprising a planetary gear set, a ring gear assembly, a thrust head assembly, an input assembly, a housing, and an upper cover, characterized in that: The planetary gear set is installed on the thrust head assembly, the ring gear assembly is sleeved outside a plurality of planetary gears of the planetary gear set, the planetary gear set is connected to the housing through the ring gear assembly, a plurality of planetary gears of the planetary gear set are in spline fit with the ring gear assembly and axially fixed, the external teeth of the planetary gears are herringbone teeth, the ring gear assembly comprises an upper ring gear, a lower ring gear, and a fixing sleeve, both the upper ring gear and the lower ring gear have internal teeth, and the internal teeth of the upper ring gear and the internal teeth of the lower ring gear can be combined into complete herringbone teeth. The specific assembly steps of this speed reducer are as follows:

[0007] Step 1) Independently assemble the thrust head assembly. Among them, a base, a bearing plate, a bearing housing, a thrust head, and a thrust head spline sleeve are sequentially sleeved on the output shaft of the thrust head assembly from bottom to top. The bottom of the thrust head is inserted into the bearing housing, and the base, the bearing plate, and the bearing housing are fixedly connected. The thrust head, the thrust head spline sleeve, and the output shaft are fixedly connected. The coaxiality error of the output shaft, the base, the bearing plate, and the bearing housing is ≯0.05 mm, and the radial runout error of the output shaft, the thrust head, and the thrust head spline sleeve is not greater than 0.02 mm; After the sun gear is installed on the planet carrier, install a plurality of planetary gears around the sun gear one by one on the planet carrier; After the planetary gears are installed, install the lower ring gear, the upper ring gear, and the fixing sleeve in sequence, so that the internal teeth of the lower ring gear mesh with the lower half of the tooth profiles of the plurality of planetary gears, the internal teeth of the upper ring gear mesh with the upper half of the tooth profiles of the plurality of planetary gears, the fixing sleeve is sleeved outside the upper ring gear and the lower ring gear, and both the upper ring gear and the lower ring gear are in spline fit with the fixing sleeve and axially fixed; Among them, two jacking tools are installed on the planet carrier to support the lower ring gear. The two jacking tools are arranged oppositely. The mounting seat of the jacking tool is fixed on the planet carrier, and the screw threadedly connected to the mounting seat abuts against the bottom of the lower ring gear; Rotating the screws of the two jacking tools can adjust the relative position of the upper ring gear and the lower ring gear, as well as the heights of the upper ring gear, the lower ring gear, the fixing sleeve, the sun gear, and the plurality of planetary gears;

[0008] Step 2) Hoist the planet carrier installed with the jacking tools, the fixing sleeve, the upper ring gear, the lower ring gear, and a plurality of planetary gears above the thrust head assembly, and fixedly connect the planet carrier to the thrust head spline sleeve of the thrust head assembly;

[0009] Step 3) Install the housing, the fixing ring of the ring gear assembly, and the upper cover in sequence, so that the housing is sleeved on the planetary gear train assembly and the thrust head assembly. Then fix the housing to the base of the thrust head assembly. Then hoist the fixing ring and fix it on the top of the housing, and the internal teeth of the fixing ring and the external teeth of the fixing sleeve are meshed and axially fixed through a snap ring. Then remove the two jacking tools. Then fix the upper cover on the top of the fixing ring.

[0010] In this way, the ring gear is jacked up by the jacking tooling, enabling the planetary gear train assembly and the thrust head to be gradually assembled independently, which can improve the overall assembly efficiency and accuracy of the speed reducer; through the calibration tooling, the distances between various components are verified at multiple points, which can effectively ensure the coaxiality between each component and reduce the risk of rework and damage to the speed reducer.

[0011] Preferably, the planetary gear set includes multiple planetary gear shafts, and multiple planetary gears are respectively mounted on the planet carrier through the multiple planetary gear shafts. The planet carrier is provided with multiple second mounting holes for mounting the planetary gear shafts; in the step 1), during the installation of the planetary gear, first move the planetary gear to the planet carrier. After inserting the centering tooling into the second mounting hole and the shaft hole of the planetary gear, install the fixing tooling on the planet carrier to clamp and position the planetary gear with the fixing tooling and the sun gear. Then, take out the centering tooling inserted into the second mounting hole and the shaft hole of the planetary gear, insert the planetary gear shaft into the second mounting hole and the shaft hole of the planetary gear, and after fixing the planetary gear shaft and the planet carrier, remove the fixing tooling.

[0012] Preferably, the centering tooling includes a first centering part and a second centering part in a ring shape. When the second mounting hole of the centering tooling and the shaft hole of the planetary gear are aligned, the first centering part is located inside the shaft hole and is in a tight fit, and the second centering part is located inside the second mounting hole and is in a tight fit. The centering tooling is made of nylon.

[0013] Preferably, the planetary gear shaft is coated with a babbit alloy coating, and the planetary gear shaft is inserted into the second mounting hole and the shaft hole of the planetary gear after being pre-cooled.

[0014] Preferably, the fixing tooling includes a connecting part that can be fixed to the planet carrier, and a blocking part for abutting against the planetary gear protrudes from the top of the connecting part.

[0015] Preferably, the external teeth of the upper ring gear and the external teeth of the lower ring gear are processed simultaneously by installing the upper ring gear and the lower ring gear on the tooth alignment tooling together; first positioning marks are engraved on both the upper ring gear and the lower ring gear. The two first positioning marks are engraved on the upper ring gear and the lower ring gear respectively when the external teeth of the upper ring gear and the external teeth of the lower ring gear are processed; in the step 1), when installing the upper ring gear, before the upper ring gear meshes with multiple planetary gears, rotate the upper ring gear according to the position where the first positioning mark on the lower ring gear is located. After the upper ring gear meshes with multiple planetary gears, rotate the screw of the jacking tooling to make the two first positioning marks located on the upper ring gear and the lower ring gear correspond to each other, realizing fine adjustment of the relative position between the upper ring gear and the lower ring gear, and making the circular runout error between the upper ring gear and the lower ring gear not exceed 0.03 mm.

[0016] Preferably, in the above step 1), during the assembly process of the thrust head assembly, after the output shaft is vertically lifted and moved to the workbench, the base, the bearing plate, the thrust head, and the thrust head spline sleeve are sequentially sleeved on the output shaft. Then, a plurality of thrust bearing assemblies are installed between the thrust head and the bearing plate. Then, the bearing housing is sleeved outside the thrust head and fixed to the base. Then, a plurality of guide bearing assemblies are sequentially installed inside the bearing housing. Among them, the top of the output shaft is inserted into the thrust head spline sleeve, and the output shaft and the thrust head spline sleeve are in spline fit, and the thrust head and the thrust head spline sleeve are fixed on the output shaft. During the assembly process of the thrust head assembly, taking the output shaft of the calibration tooling as a reference, the distances between the output shaft and the base, the bearing plate, and the bearing housing are measured, and the base, the bearing plate, and the bearing housing are moved according to the results of the calibration tooling to make the output shaft, the base, the bearing plate, and the bearing housing coaxial.

[0017] Preferably, the output shaft, the thrust head, and the thrust head spline sleeve are all marked with corresponding second positioning marks. The second positioning marks are respectively marked on the output shaft, the thrust head, and the thrust head spline sleeve after precision grinding when the output shaft, the thrust head, and the thrust head spline sleeve are assembled before the assembly of the thrust head assembly. In the above step 1), during the assembly process of the thrust head assembly, through the second positioning mark on the output shaft, the positions of the thrust head and the thrust head spline sleeve are adjusted so that the relative positions of the second positioning marks located on the output shaft, the thrust head, and the thrust head spline sleeve after assembly are the same as the relative positions of the three second positioning marks located on the output shaft, the thrust head, and the thrust head spline sleeve after precision grinding.

[0018] Preferably, both the inner side and the outer side of the top of the bearing housing have light-exposed sections, and the light-exposed sections are formed on the bearing housing after the base and the bearing housing are installed together. In the above step 1), when positioning the bearing housing, the distance between the light-exposed section and the outer surface of the thrust head is measured by the calibration tooling, and the position of the bearing housing is adjusted according to the results of the calibration tooling to make the bearing housing coaxial with the thrust head.

[0019] Preferably, the calibration tooling includes a depth gauge. The depth gauge includes an abutting portion and a measuring portion with scale marks. The measuring portion is slidably installed on the abutting portion. The abutting portion includes a measuring surface for abutting against the workpiece, and the measuring surface includes an arc-shaped section for abutting against the outer circular surface of the workpiece. In this way, the arc-shaped section of the measuring surface can abut against the outer circular surface of the component, improving the detection accuracy of the depth gauge.

[0020] The beneficial effects of the technical solution of the present invention are as follows: 1) By using the jacking tooling to jack up the ring gear, the planetary gear train assembly and the thrust head can be gradually assembled independently, which can improve the overall assembly efficiency and accuracy of the reduction gearbox. At the same time, the telescopic end on the jacking tooling that can change its length can effectively adjust the abutting position and relative angle between the ring gear and the planetary gear, making the cooperation between the various components of the reducer more smooth. 2) The centering tooling and the fixing tooling can greatly improve the installation efficiency of the planetary gear shaft, avoiding repeated installation and repositioning, as well as the collision between the planetary gear shaft, the planet carrier and the planetary gear during installation. 4) The positioning marks between the thrust head, the output shaft and the thrust head spline sleeve can effectively improve the positioning efficiency and accuracy between the various components, making the transmission of the reduction gearbox more stable. 5) By using the calibration tooling to perform multi-point verification on the spacing between the various components, the coaxiality between the various components can be effectively guaranteed, reducing the risk of rework and damage to the reduction gearbox. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a schematic diagram of the overall structure of the reduction gearbox;

[0022] Figure 2 FIG. is a state diagram of using the centering tooling and the fixing tooling to fix the position of the planetary gear;

[0023] Figure 3 FIG. is a schematic diagram of the structure of the centering tooling;

[0024] Figure 4 FIG. is a schematic diagram of the structure of the fixing tooling;

[0025] Figure 5 FIG. is a state diagram of using the jacking tooling to jack up the lower ring gear and the upper ring gear;

[0026] Figure 6 FIG. is a schematic diagram of the structure of the jacking tooling;

[0027] Figure 7 FIG. is a schematic diagram of the structure of the calibration tooling;

[0028] Figure 8 FIG. is a schematic diagram of the installation structure of the base, the bearing plate and the bearing housing;

[0029] Figure 9 FIG. is a schematic diagram of the structure of the planetary gear shaft.

[0030] Reference Numerals: 1, output shaft; 2, base; 3, bearing housing; 4, thrust bearing assembly; 5, guide bearing assembly; 6, thrust head; 7, spline sleeve of thrust head; 8, planet carrier; 9, lower gear ring; 10, upper gear ring; 11, fixing sleeve; 12, fixing ring; 13, upper cover; 17, mechanical pump assembly; 18, adapter device; 19, central oil pipe; 20, sun gear; 201, intermediate through hole; 21, planet gear shaft; 211, first positioning groove; 212, notch; 22, planet gear; 221, shaft hole; 23, fuel injection pipe; 24, housing; 25, jacking tooling; 251, mounting seat; 252, screw; 26, calibration tooling; 261 depth gauge; 2611, abutting portion; 26111, measuring surface; 2612, measuring portion; 27, centering tooling; 271, first centering portion; 272, second centering portion; 273, lifting hole; 28, fixing tooling; 281, connecting portion; 282, blocking portion; 31, visible section; 33, bearing plate; 34, high-level oil sleeve; 81, cavity; 811, first mounting hole; 812, second mounting hole; 813, third mounting hole; 814, second positioning hole; 82, opening. Detailed Embodiment

[0031] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0033] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more, unless otherwise clearly defined.

[0034] In the present invention, unless otherwise clearly specified or limited, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature. Embodiment

[0036] The assembly method of the speed reducer is used for the assembly of the speed reducer, as Figures 1-9 shown. The speed reducer includes a planetary gear set, a ring gear assembly, a thrust head assembly, an input assembly, a housing and an upper cover. It is characterized in that: the planetary gear set is mounted on the thrust head assembly, the ring gear assembly is sleeved outside a plurality of planetary gears of the planetary gear set, the planetary gear set is connected to the housing through the ring gear assembly, a plurality of planetary gears 22 of the planetary gear set are in spline fit and axially fixed with the ring gear assembly, the external teeth of the planetary gear 22 are herringbone teeth, the ring gear assembly includes an upper ring gear 10, a lower ring gear 9 and a fixing sleeve 11, both the upper ring gear 10 and the lower ring gear 9 have internal teeth, and the internal teeth of the upper ring gear 10 and the internal teeth of the lower ring gear 9 can be combined into a complete herringbone tooth. The specific assembly steps of the speed reducer are as follows:

[0037] Step 1), assemble the thrust head assembly independently. Among them, the output shaft 1 of the thrust head assembly is sleeved with a base 2, a bearing plate 33, a bearing housing 3, a thrust head 6, and a thrust head spline sleeve 7 from bottom to top. The bottom of the thrust head 6 is inserted into the bearing housing 3. The base 2, the bearing plate 33, and the bearing housing 3 are fixedly connected. The thrust head 6, the thrust head spline sleeve 7, and the output shaft 1 are fixedly connected. The coaxiality error of the output shaft 1, the base 2, the bearing plate 33, and the bearing housing 3 is not more than 0.05 mm, and the radial runout error of the output shaft 1, the thrust head 6, and the thrust head spline sleeve 7 is not more than 0.02 mm. After the sun gear 20 is installed on the planet carrier 8, a plurality of planet gears 22 are successively installed on the planet carrier 8 around the sun gear 20. After the installation of the planet gears 22 is completed, the lower ring gear 9, the upper ring gear 10, and the fixing sleeve 11 are installed in sequence, so that the internal teeth of the lower ring gear 9 mesh with the lower half tooth profiles of the plurality of planet gears 22, the internal teeth of the upper ring gear 10 mesh with the upper half tooth profiles of the plurality of planet gears 22, the fixing sleeve 11 is sleeved outside the upper ring gear 10 and the lower ring gear 9, and both the upper ring gear 10 and the lower ring gear 9 are in spline fit with the fixing sleeve 11 and axially fixed. Among them, two jacking tools 25 are installed on the planet carrier 8 to support the lower ring gear 9. The two jacking tools 25 are arranged oppositely. The mounting seat 251 of the jacking tool 25 is fixed on the planet carrier 8, and the screw 252 threadedly connected to the mounting seat 251 abuts against the bottom of the lower ring gear 9. Rotating the screws 252 of the two jacking tools 25 can adjust the relative positions of the upper ring gear 10 and the lower ring gear 9, as well as the heights of the upper ring gear 10, the lower ring gear 9, the fixing sleeve 11, the sun gear 20, and the plurality of planet gears 22.

[0038] Step 2), hoist the planet carrier 8 installed with the jacking tools 25, the fixing sleeve 11, the upper ring gear 10, the lower ring gear 9, and the plurality of planet gears 22 above the thrust head assembly, and fixedly connect the planet carrier 8 with the thrust head spline sleeve 7 of the thrust head assembly.

[0039] Step 3), install the box body 24, the fixing ring 12 of the ring gear assembly, and the upper cover 13 in sequence, so that the box body 24 is sleeved on the planetary gear train assembly and the thrust head assembly. Then fix the box body 24 to the base 2 of the thrust head assembly. Then hoist the fixing ring 12 and fix it on the top of the box body 24. The internal teeth of the fixing ring 12 mesh with the external teeth of the fixing sleeve 11 and are axially fixed by a circlip. Then remove the two jacking tools 25. Then fix the upper cover 13 on the top of the fixing ring 12.

[0040] In this way, during the assembly process of the speed reducer, the planetary gear train assembly and the thrust head assembly, the two main components, are assembled independently and then assembled together, which is convenient for controlling the assembly quality of a single component. During the assembly process of the planetary gear train assembly, the ring gear and the fixed sleeve are jacked up by the jacking tooling. On the one hand, it avoids the weight of the ring gear and the fixed sleeve being always released on the external teeth of the planetary gears and the internal teeth of the ring gear, reducing the impact on the planetary gear train assembly during the assembly process. On the other hand, through the retractable jacking tooling, the inclination angle between the ring gear and the planetary gears can be adjusted, making the transmission of the planetary gear train assembly more stable, avoiding accidents such as tooth breakage, and improving the service life and transmission effect of the speed reducer. During the assembly process of the thrust head assembly, the coaxiality between the various components in the planetary gear set is checked repeatedly, reducing the radial runout between the input end and the output end of the thrust head assembly and reducing the risk of failure of the thrust head assembly.

[0041] In this embodiment, as Figure 2 and Figure 5 shown, the planetary gear set includes a planetary carrier 8, a sun shaft 20, a central oil pipe 19, a plurality of spray oil pipes 23, a plurality of planetary gears 21 and a plurality of planetary gear shafts 22. Among them, the inside of the planetary carrier 8 is a cavity 81 and a plurality of openings 82 communicating with the inside of the planetary carrier 8 are provided on the side surface of the planetary carrier 8. A plurality of mounting holes penetrating the cavity 81 from top to bottom are provided on the planetary carrier 8. The mounting holes include a first mounting hole 811, a plurality of second mounting holes 812 and a plurality of third mounting holes 813. The first mounting hole 811 is located in the middle position of the planetary carrier 8. A plurality of second mounting holes 812 are arranged around the first mounting hole 811. A plurality of third mounting holes 813 are arranged around the first mounting hole 811. A plurality of third mounting holes 813 are located inside a plurality of second mounting holes 812. The planetary gear 22 has a shaft hole 221 for mounting the planetary gear shaft 21. The external teeth of the planetary gear 22 are herringbone teeth. A middle through hole 201 penetrating through itself is provided on the sun gear 20. The external teeth of the sun gear 20 are herringbone teeth. After inserting the plurality of spray oil pipes 23 into the plurality of third mounting holes 813 respectively and fixing the two ends of the spray oil pipes 23 to the upper and lower ends of the planetary carrier 8 respectively, the sun gear 20 is inserted into the first mounting hole 811. Further preferably, as Figures 2-4As shown in the figure, in the above step 1), the installation process of the planet gear 22 is as follows: By visually adjusting the relative positions of the shaft hole 221 of the planet gear 22 and the second mounting hole 812 of the planet carrier 8, the initial centering and positioning of the shaft hole 221 of the planet gear 22 and the second mounting hole 812 of the planet carrier 8 are completed; vertically lift the centering tooling 27, so that the centering tooling 27 is inserted from top to bottom and passes through the second mounting hole 812 on the upper side. After that, the annular first centering part 271 on the centering tooling 27 is inserted into the shaft hole 221 of the planet gear 22, and the annular second centering part 272 on the centering tooling 27 is inserted into the second mounting hole 812 on the lower side. Among them, the first centering part 271 is in interference fit with the shaft hole 221, the second centering part 272 is in interference fit with the second mounting hole 812 on the lower side, and the first centering part 271 and the second centering part 272 are concentric, completing the centering and positioning of the shaft hole 221 of the planet gear 22 and the second mounting hole 812 of the planet carrier 8; Install the fixing tooling 28 on the side of the planet carrier 8, and clamp the planet gear 22 through the fixing tooling 28 and the sun gear 20 to prevent the radial movement of the planet gear. Among them, the external teeth of the planet gear 22 and the external teeth of the sun gear 20 are both herringbone teeth, and the axial movement of the planet gear is prevented by the meshing teeth of the planet gear 22 and the sun gear 20, completing the fixation of the centering position of the shaft hole 221 of the planet gear 22 and the second mounting hole 812 of the planet carrier 8.

[0042] Further preferably, the material of the centering tooling 27 is nylon. With this setting, using a material with relatively soft properties can prevent the centering tooling 27 from damaging the surface of the shaft hole 221. Further preferably, at least two lifting holes 273 for installing lifting rings are provided at the top of the first centering part, and the axis of the lifting hole 273 is parallel to the central axis of the first centering part. Further preferably, a plurality of lifting holes 273 for installing lifting lugs are opened at the top of the first centering part 271. In the above step 2), before moving the centering tooling 27, install lifting lugs at the lifting holes 273, and horizontally lift the centering tooling 27 through the lifting lugs. With this setting, the lifting of the centering tooling is facilitated through the lifting holes. The annular centering tooling effectively reduces its own weight, facilitating the movement of the centering tooling, and can reduce the conflict between the centering tooling and the inner hole of the planet gear during the centering process, reducing the damage to the inner hole of the planet gear.

[0043] Further preferably, the fixing tooling 28 includes a connecting part 281 that can be fixed to the planet carrier 8. A blocking part 282 for abutting against the planet gear 22 protrudes from the top of the connecting part 281, and the connecting part 281 can be fixed to the planet carrier 8 by bolts. With this setting, on the premise of meeting the assembly requirements, the structure of the tooling is simplified, and the manufacturing difficulty and cost of the tooling are reduced.

[0044] Further preferably, the aperture of the second mounting hole 812 on the upper side is larger than that of the second mounting hole 812 on the lower side. The planetary gear shaft 21 is a stepped shaft, with a smaller outer diameter at the bottom of the planetary gear shaft 21. The outer diameter of the first positioning portion 271 in the centering tooling is larger than that of the second positioning portion 272. Such a setting facilitates the positioning of the planetary gear and the installation of the planetary gear shaft.

[0045] Further preferably, one end of the planetary gear shaft 21 is axially fixed to the planet carrier 8, and the other end of the planetary gear shaft 21 is radially fixed to the planet carrier 8. Such a setting avoids the influence of a complex fixing structure on the positional accuracy between the planet carrier and the planetary gear shaft. Further preferably, the top of the planetary gear shaft 21 is in interference fit with the second mounting hole 812 on the upper side. A first positioning hole 815 is reamed at the joint of the planetary gear shaft 21 and the second mounting hole 812 on the upper side, and a first positioning pin is driven into the first positioning hole 815 to prevent the axial rotation of the planetary gear shaft 21; the bottom of the planetary gear shaft 21 is located in the second mounting hole 812 on the lower side, and the bottom of the planetary gear shaft 21 is in interference fit with the second mounting hole 812 on the lower side. An annular positioning groove 211 is provided at the bottom of the planetary gear shaft 21, and a second positioning hole 814 communicating with the second mounting hole 812 on the lower side is provided on the planet carrier 8. A second positioning pin is driven into the second positioning hole 814, and one end of the second positioning pin passes through the second positioning hole 814 and is inserted into the positioning groove 211. Such a setting fixes the planetary gear shaft axially and radially in two ways, and the two positioning methods do not affect each other, making the positioning of the planetary gear shaft and the planet carrier more accurate.

[0046] Further preferably, the planetary gear shaft 21 is coated with a babbit alloy coating, and the planetary gear shaft 21 and the planetary gear 22 slide against each other through the babbit alloy coating; before hoisting the planetary gear shaft 21 in step 3), the planetary gear shaft 21 is pre-cooled to -50 °C, and white oil is applied to the outer surface of the planetary gear shaft 21. Such a setting avoids the collision between the planetary gear shaft and the shaft hole, facilitates the installation of the planetary gear shaft, and improves the installation efficiency and success rate. Further preferably, as Figure 5 shown, a notch 212 is provided on the planetary gear shaft 21; when the planetary gear shaft 21 is installed, the notch of the planetary gear shaft 21 should be parallel to the tangent direction of the rotation path of the planet carrier 8.

[0047] Further preferably, the planet carrier 8 needs to be subjected to a static balance test before assembly, and it is required that the unbalance of the planet carrier 8 ≯ 50 g. Such a setting ensures the stability and reliability of the planetary gear set during operation.

[0048] In this embodiment, before installing the sun gear 20, a plurality of fuel injection pipes 23 are inserted into the third installation holes 813 one by one, and the fuel injection pipes 813 are fixed to the planet carrier 8. After the installation of the fuel injection pipes 23, both ends of the fuel injection pipes 23 do not extend beyond the planet carrier 8. In this way, interference between the fuel injection pipes 23 and other components is avoided. Further preferably, the fuel injection pipes 23 are provided with fuel injection holes, and the fuel injection holes are oriented towards the meshing position of the sun gear 20 and the planet gears 22. With such a setting, lubrication and cooling protection are provided more directly for the internal transmission structure of the planet gear set. Further preferably, the fixing method of the fuel injection pipes 23 is to expand both ends of the fuel injection pipes 23 and fix the fuel injection pipes to the planet carrier 8 through bolts and glue. With such a setting, flaring both ends of the fuel injection pipes 23 can effectively prevent the axial movement of the fuel injection pipes 23 and improve the connection strength and stability of the components in the planet gear set. Further preferably, after the fuel injection pipes are coated with glue, the planet carrier 8 is heated to 150 °C. With such a setting, the solidification of the glue is accelerated and the assembly efficiency is improved. Further preferably, after all the planet gears 22 are installed on the planet carrier 8, the intermediate oil pipe 19 is installed; the first installation hole 811 located on the lower side is a countersunk hole, and a mounting seat is fixedly installed on the bottom end of the intermediate oil pipe 19; the mounting seat is inserted into the countersunk hole and fixedly connected to the bottom of the planet carrier 22.

[0049] In this embodiment, the external teeth of the upper ring gear 10 and the external teeth of the lower ring gear 9 are machined simultaneously by installing the upper ring gear 10 and the lower ring gear 9 together on a tooth alignment tool; first positioning marks are engraved on both the upper ring gear 10 and the lower ring gear 9. The two first positioning marks are engraved on the upper ring gear 10 and the lower ring gear 9 respectively when the external teeth of the upper ring gear 10 and the external teeth of the lower ring gear 9 are machined. In step 1, when installing the upper ring gear 10, before the upper ring gear 10 meshes with the plurality of planet gears 22, the upper ring gear 10 is rotated through the position where the first positioning mark on the lower ring gear 9 is located. After the upper ring gear 10 meshes with the plurality of planet gears 22, the screw 252 of the jacking tool 25 is rotated to make the two first positioning marks located on the upper ring gear 10 and the lower ring gear 9 correspond to each other, realizing fine adjustment of the relative positions of the upper ring gear 10 and the lower ring gear 9, so that the circular runout error between the upper ring gear 10 and the lower ring gear 9 does not exceed 0.03 mm. With such a setting, the installation and positioning of the ring gears are facilitated, the stability of the ring gears during operation is improved, and the assembly efficiency and success rate of the speed reducer are improved.

[0050] Further preferably, after the upper gear ring 10 and the lower gear ring 9 are fixed on the tooth alignment tooling, the distance between the top of the upper gear ring 10 and the bottom of the lower gear ring 9 is greater than the height of the calibration tire. The lower pressing plate of the tooth alignment tooling is fixedly connected to the bottom of the calibration tire and the bottom of the lower gear ring 9 respectively through a plurality of bolts, and is fixedly connected to the top of the calibration tire and the top of the upper gear ring 10 respectively through a plurality of bolts; wherein both the lower pressing plate and the upper pressing plate are circular, the outer diameter of the lower pressing plate is smaller than the root circle diameter of the lower gear ring 9, and the outer diameter of the upper pressing plate is smaller than the root circle diameter of the upper gear ring 10. After the external teeth of the upper gear ring 10 and the lower gear ring 9 are processed, the circular runout error between the upper gear ring 10 and the lower gear ring 9 does not exceed 0.03 mm. With such a setting, the external teeth of the upper gear ring and the lower gear ring have high consistency through the above method, and after being paired by the first positioning mark, the tooth profiles of the external teeth of the upper gear ring are consistent with the tooth profiles of the external teeth of the lower gear ring, reducing errors, improving the installation efficiency and installation accuracy, and making the transmission process more stable.

[0051] Further preferably, the mounting seat 251 of the jacking tooling 25 is fixed to the side of the planet carrier 8 through two bolts. The threaded section of the bolt passes through the mounting seat 251 and is threadedly connected to the planet carrier 8. The two bolts are arranged on both sides of the screw rod 252; when installing the jacking tooling 25, rotate the two bolts respectively to adjust the length of the bolts connected to the planet carrier 8, thereby adjusting the inclination angle of the mounting seat 251, and then finely adjusting the position where the screw rod 252 contacts the lower gear ring 9, and finely adjusting the relative position of the screw rods 252 on the two jacking toolings 25. With such a setting, it is convenient to adjust the accuracy of the relative position between the two screw rods, making the effect of the jacking tooling more obvious and facilitating the adjustment of the relative position between the upper gear ring and the lower gear ring. Further preferably, the screw rod 252 of the jacking tooling 25 abuts against the bottom of the lower gear ring 9 through a gasket. With such a setting, the stress area of the lower gear ring is increased, preventing damage to the lower gear ring 9.

[0052] Further preferably, two annular positioning grooves are provided inside the fixing sleeve 11, and the two positioning grooves are arranged in the vertical direction and are provided on the internal tooth section of the fixing sleeve 11. In step 4) above, the axial fixing method of the upper gear ring 10, the lower gear ring 9 and the fixing sleeve 11 is as follows: before hoisting the fixing sleeve 11, install the upper snap ring 110 in the upper positioning groove, and after the fixing sleeve 11 is hoisted, install the lower snap ring 111 in the lower positioning groove. The external teeth of the upper gear ring 10 and the external teeth of the lower gear ring 9 are located between the upper snap ring 110 and the lower snap ring 111. With such a setting, the axial positions of the upper and lower gear rings are adjusted, enabling the herringbone teeth to be radially meshed and centered, and the external teeth to be aligned, connecting the fixing sleeve, the upper gear ring and the lower gear ring into an integral whole.

[0053] In this embodiment, in the above step 1), during the assembly process of the thrust head assembly, after the output shaft 1 is vertically lifted and moved to the workbench, the base 2, the bearing plate 33, the thrust head 6, and the thrust head spline sleeve 7 are successively sleeved on the output shaft 1. Then, a plurality of thrust bearing assemblies 4 are installed between the thrust head 6 and the bearing plate 33. Then, the bearing housing 3 is sleeved outside the thrust head and fixed to the base 2. Then, a plurality of guide bearing assemblies 5 are successively installed inside the bearing housing 3. Among them, the top of the output shaft 1 is inserted into the thrust head spline sleeve 7, and the output shaft 1 and the thrust head spline sleeve 7 are in spline fit. The thrust head 6 and the thrust head spline sleeve 7 are fixed on the output shaft 1. During the assembly process of the thrust head assembly, taking the output shaft of the calibration tooling 26 as the reference, the distances between the output shaft 1 and the base 2, the bearing plate 33, and the bearing housing 3 are measured, and the base 2, the bearing plate 33, and the bearing housing 3 are moved according to the results of the calibration tooling, so that the output shaft 1, the base 2, the bearing plate 33, and the bearing housing 3 are coaxial. With such a setting, the coaxiality of the thrust head assembly is improved, and the occurrence of bearing burning due to excessive radial runout during operation is avoided.

[0054] Further preferably, before the installation of the thrust head assembly, after the thrust head 6, the thrust head spline sleeve 7, and the output shaft 1 are independently processed, the thrust head 6 and the thrust head spline sleeve 7 are fixed on the output shaft 1, and the input end of the thrust head spline sleeve 7, the output end of the output shaft 1, and the bearing surface of the thrust head 6 are finely ground. After the fine grinding is completed, corresponding second positioning marks are made on the thrust head spline sleeve 7, the output shaft 1, and the thrust head 6 respectively. The bearing housing 3 is fixed to the base 2 to make the base 2 and the bearing housing 3 coaxial, and then light-exposed sections 31 used as measurement references are machined on the inner side and the outer side of the top of the bearing housing 3 respectively. Among them, after the fine grinding, the radial runout error between the thrust head 6, the thrust head spline sleeve 7, and the output shaft 1 is not greater than 0.02 mm, the total runout error on the thrust head 6 does not exceed 0.015 mm, the surface finish of the input end of the thrust head spline sleeve 7 and the output end of the output shaft 1 is not greater than 0.8, the surface finish of the bearing surface of the thrust head is not greater than 0.4, and the cylindricity of the output shaft 1, the thrust head 6, and the thrust head spline sleeve 7 is 0.01.

[0055] Further preferably, when the thrust head assembly is installed, the output shaft 1 is vertically hoisted to a flat workbench, the output end of the output shaft 1 faces downward, and a plurality of equal-height cushion blocks are arranged around the output shaft 1 on the table position. After the base 2 is sleeved on the output shaft, it is placed on the plurality of elevated cushion blocks. Among them, the workbench is circular. When hoisting the output shaft, the distances between the outer circular surface of the output shaft 1 and the outer circular surface of the workbench are measured at multiple points through the calibration tooling 26, and the position of the output shaft 1 is adjusted according to the results of the calibration tooling 26 to make the output shaft 1 coaxial with the workbench. With such a setting, it is ensured that the reducer is always in the middle position of the workbench, and the accuracy of the reducer assembly process is improved.

[0056] Further preferably, during the installation process of the thrust head assembly, the base 2, the bearing plate 33, the thrust head 6, and the thrust head spline sleeve 7 are successively lifted horizontally and then sleeved on the output shaft 1. Then, a plurality of thrust bearing tile assemblies 4 are successively installed in the gap between the thrust head 6 and the bearing plate 33. Then, the bearing housing 3 is installed so that the thrust head 6 and the plurality of thrust bearing tile assemblies 4 are both located inside the bearing housing 3. The distance between the visible section 31 on the bearing housing 3 and the bearing surface of the thrust head 6 is measured by the calibration tooling 26. After adjusting the position of the bearing housing 3 according to the measurement results, the bearing housing 3 is fixed on the bearing plate 33. Then, a plurality of guide bearing tile assemblies 5 are successively installed inside the bearing housing 3. Among them, the base 2 is placed on a plurality of equal-height cushion blocks, and the bearing plate 33 is located above the base 2. The coaxiality of the base 2, the bearing plate 33, and the output shaft 1 is measured at multiple points by using the calibration tooling 26. After adjusting the positions of the base 2 and the bearing plate 33 according to the results of the calibration tooling 26, the bearing plate 33 is fixed on the base 2. When hoisting the thrust head 6 and the thrust head spline sleeve 7, the thrust head 6 and the thrust head spline sleeve 7 are rotated according to the position of the second positioning mark on the output shaft, so that the relative positions of the second positioning marks on the output shaft 1, the thrust head 6, and the thrust head spline sleeve 7 after assembly are the same as the relative positions of the three second positioning marks on the output shaft 1, the thrust head 6, and the thrust head spline sleeve 7 after finish grinding. With such a setting, it is convenient for the installation and positioning of the thrust head assembly, and the installation efficiency and installation accuracy of the thrust head assembly are improved.

[0057] Further preferably, the calibration tooling 26 includes a depth gauge 261, a micrometer, a dial indicator, etc. The depth gauge 261 includes an abutting portion 2611 and a measuring portion 2612 with scale marks. The measuring portion 2612 is slidably installed at the middle position of the abutting portion 2611. The abutting portion 2611 includes a measuring surface 26111 for abutting against the workpiece. The middle position of the measuring surface 26111 is the abutting surface, and the abutting surface is recessed in an arc shape. With such a setting, the problem of measurement distortion caused by the arc-shaped outer circle of the tool is avoided, and the distance between the two arc surfaces can be easily measured by abutting the arc-shaped section of the measuring surface against the outer circle surface, which speeds up the calibration process of the thrust head assembly. Taking the measurement of the coaxiality between the output shaft and the workbench as an example: when using the depth gauge 261 to calibrate the coaxiality of the workbench and the output shaft 1, the abutting surface of the abutting portion 2611 abuts against the outer circle surface of the workbench, the measuring portion 2612 is slid so that one end of it abuts against the output shaft 1, and the value of the measuring portion 2612 is read, then the distance between the outer circle surface of the workbench and the outer circle surface of the output shaft 1 can be obtained. The position of the output shaft 1 is adjusted according to the measurement results of the depth gauge 261 to make the workbench and the output shaft coaxial.

[0058] Further preferably, the thrust head 6 is preheated to 150 °C and then hoisted and sleeved on the output shaft 1. In this way, based on the principle of thermal expansion and contraction, it is convenient for the sleeving of the thrust head 6, reduces the installation difficulty of the thrust head, and reduces the collision between the thrust head and the output shaft during the installation process.

[0059] Further preferably, during the assembly process of the thrust head assembly, after the bearing plate 33 is sleeved and fixed on the high-position oil sleeve 34, the bearing plate 33 and the high-position oil sleeve 34 fixed together are jointly sleeved on the output shaft, and the top section of the high-position oil sleeve 34 is inserted into the thrust head 6; after the thrust head 6 and the thrust head spline sleeve 7 are fixed together, they are installed on the output shaft together. In this way, the assembly efficiency of the thrust head assembly is improved, and the assembly difficulty of the thrust head assembly is reduced. Further preferably, the coaxiality of the base 2, the bearing plate 33, the high-position oil sleeve 34 and the output shaft 1 is not more than 0.05 mm. Further preferably, the bearing housing 3 is composed of two semi-circular bearing housing shells spliced together. Such a setting facilitates the installation of the bearing housing.

[0060] In this embodiment, the output shaft 1 has a shaft shoulder, and the thrust head 6 has a stepped through hole 61. When the thrust head 6 is sleeved on the output shaft 1, the thrust head 6 presses on the shaft shoulder of the output shaft 1, and the thrust head spline sleeve 7 is spline-connected to the output shaft 1; when the thrust head is fixed, the pressing plate presses the thrust head spline sleeve 7 tightly, and the pressing plate is fixedly connected to the top of the output shaft 1 through bolts, thereby fixing the output shaft, the thrust head and the thrust head spline sleeve.

[0061] In this embodiment, after the planetary gear train assembly and the thrust head assembly are spliced, the box body 24, the fixing ring 12 and the upper cover 13 are installed in sequence; wherein the box body 24 is sleeved outside the planetary gear train and the thrust head assembly, and the base 2 is fixed to the box body 24; the fixing ring 12 is installed on the top of the box body 24, the fixing sleeve 11 extends from the inside of the box body 24 to the inside of the fixing ring 12, and the external teeth of the fixing sleeve 11 are engaged with the internal teeth of the fixing ring 12, and the fixing sleeve 11 and the fixing ring 12 are axially fixed; the upper cover 13 is fixed on the top of the fixing ring 12. After the fixing ring 12 is installed, the multiple jacking tools 25 on the planetary gear 22 are removed.

[0062] In this embodiment, a mechanical pump 17 is further installed on the upper cover 13, and the input end of the mechanical pump 17 extends into the box body 24; before the upper cover 13 is installed, a disk device 18 with external teeth is installed on the top of the planetary carrier 8. After the upper cover 13 is installed, the external teeth of the disk device 18 are engaged with the gear on the input end of the mechanical pump 17. The upper cover 13 has a middle hole, the middle of the disk device 18 protrudes upward to form a boss, and a boss middle hole is provided on the boss. The top section of the sun gear 20 is inserted into the boss middle hole. The boss of the disk device 18 extends out of the middle hole of the upper cover 13. After the upper cover 13 is installed, the sealing assembly is installed in the gap between the upper cover 13 and the boss.

[0063] Further preferably, the supporting tooling includes a jack and a wooden cushion block. The jack jacks up the lower gear ring 9 through the wooden cushion block. With such an arrangement, since the fixing sleeve 11 and the upper gear ring 10 need to be hoisted subsequently, at this time, the lower gear ring 9 requires a stable and safe state. The jack can provide sufficient supporting force for the lower gear ring, and the wooden cushion block can prevent damage to the lower gear ring 9.

[0064] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0065] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. An assembly method for a speed reducer, the speed reducer comprising a planetary gear set, a ring gear assembly, a thrust head assembly, an input assembly, a housing and an upper cover, characterized in that: The planetary gear set is installed on the thrust head assembly. The ring gear assembly is sleeved outside multiple planetary gears of the planetary gear set. The planetary gear set is connected to the box body through the ring gear assembly. Multiple planetary gears (22) of the planetary gear set are in spline fit with the ring gear assembly and axially fixed. The external teeth of the planetary gear (22) are herringbone teeth. The ring gear assembly includes an upper ring gear (10), a lower ring gear (9) and a fixing sleeve (11). Both the upper ring gear (10) and the lower ring gear (9) have internal teeth. The internal teeth of the upper ring gear (10) and the internal teeth of the lower ring gear (9) can be combined into complete herringbone teeth. The specific assembly steps of this speed reducer are as follows: 1) Assemble the thrust head assembly independently. Among them, the output shaft (1) of the thrust head assembly is sequentially sleeved with a base (2), a bearing plate (33), a bearing housing (3), a thrust head (6) and a thrust head spline sleeve (7) from bottom to top. The bottom of the thrust head (6) is inserted into the bearing housing (3). The base (2), the bearing plate (33) and the bearing housing (3) are fixedly connected. The thrust head (6), the thrust head spline sleeve (7) and the output shaft (1) are fixedly connected. The coaxiality error of the output shaft (1), the base (2), the bearing plate (33) and the bearing housing (3) is ≯0.05 mm. The radial runout error of the output shaft (1), the thrust head (6) and the thrust head spline sleeve (7) is not greater than 0.02 mm. After the sun gear (20) is installed on the planet carrier (8), multiple planetary gears (22) are sequentially installed on the planet carrier (8) around the sun gear (20). After the installation of the planetary gears (22) is completed, the lower ring gear (9), the upper ring gear (10) and the fixing sleeve (11) are installed in sequence, so that the internal teeth of the lower ring gear (9) are meshed with the lower half of the tooth profiles of multiple planetary gears (22), and the internal teeth of the upper ring gear (10) are meshed with the upper half of the tooth profiles of multiple planetary gears (22). The fixing sleeve (11) is sleeved outside the upper ring gear (10) and the lower ring gear (9). Both the upper ring gear (10) and the lower ring gear (9) are in spline fit with the fixing sleeve (11) and axially fixed. Among them, two jacking tools (25) are installed on the planet carrier (8) to support the lower ring gear (9). The two jacking tools (25) are arranged oppositely. The mounting seat (251) of the jacking tool (25) is fixed on the planet carrier (8). The screw (252) threadedly connected to the mounting seat (251) abuts against the bottom of the lower ring gear (9). Rotating the screws (252) of the two jacking tools (25) can adjust the relative positions of the upper ring gear (10) and the lower ring gear (9), as well as the heights of the upper ring gear (10), the lower ring gear (9), the fixing sleeve (11), the sun gear (20) and multiple planetary gears (22); 2) Lift the planet carrier (8) installed with the jacking tool (25), the fixing sleeve (11), the upper ring gear (10), the lower ring gear (9) and multiple planetary gears (22) above the thrust head assembly, and fixedly connect the planet carrier (8) to the thrust head spline sleeve (7) of the thrust head assembly; 3) Install the box body (24), the fixing ring (12) of the ring gear assembly and the upper cover (13) in sequence, so that the box body (24) is sleeved on the planetary gear train assembly and the thrust head assembly. Then fix the box body (24) to the base (2) of the thrust head assembly. Then lift the fixing ring (12) and fix it on the top of the box body (24). And the internal teeth of the fixing ring (12) mesh with the external teeth of the fixing sleeve (11) and are axially fixed by a circlip. Then remove the two jacking tools (25). Then fix the upper cover (13) on the top of the fixing ring (12).

2. The assembly method of a speed reducer according to claim 1, characterized in that: The planetary gear set includes a plurality of planetary gear shafts (21). A plurality of planetary gears (22) are respectively installed on the planet carrier (8) through the plurality of planetary gear shafts (21). The planet carrier (8) is provided with a plurality of second mounting holes (812) for installing the planetary gear shafts (21). In the process of installing the planetary gear in step 1), first move the planetary gear (22) to the planet carrier (8). After inserting the centering tool (27) into the second mounting hole (812) of the planet carrier (8) and the shaft hole of the planetary gear (22), install the fixing tool (28) on the planet carrier (8) so that the fixing tool (28) and the sun gear (20) clamp and position the planetary gear (22). Then take out the centering tool (27) inserted into the second mounting hole (812) and the shaft hole (221) of the planetary gear (22). After inserting the planetary gear shaft (21) into the second mounting hole (812) and the shaft hole (221) of the planetary gear (22), fix the planetary gear shaft (21) and the planet carrier (8), and then remove the fixing tool (28).

3. The assembly method of a speed reducer according to claim 2, characterized in that: The centering tool (27) includes an annular first centering part (271) and a second centering part (272). When the centering tool (27) is inserted into the second mounting hole (812) of the planet carrier (8) and the shaft hole (221) of the planetary gear (22), the first centering part (271) is located in the shaft hole (221) and is in tight fit, and the second centering part (272) is located in the second mounting hole (812) and is in tight fit. The material of the centering tool (27) is nylon.

4. The assembly method of a speed reducer according to claim 2, characterized in that: The planetary gear shaft (21) is coated with a babbit alloy coating. The planetary gear shaft (21) is inserted into the second mounting hole (812) and the shaft hole (221) of the planetary gear (22) after pre-cooling.

5. The assembly method of a speed reducer according to claim 2, characterized in that: The fixing tool (28) includes a connecting part (281) that can be fixed to the planet carrier (8). A blocking part (282) for abutting against the planetary gear (22) protrudes from the top of the connecting part (281).

6. The assembly method of a speed reducer according to claim 1, characterized in that: The external teeth of the upper gear ring (10) and the external teeth of the lower gear ring (9) are machined while the upper gear ring (10) and the lower gear ring (9) are installed together on the tooth-aligning fixture; first positioning marks are engraved on both the upper gear ring (10) and the lower gear ring (9). The two first positioning marks are engraved on the upper gear ring (10) and the lower gear ring (9) respectively when the external teeth of the upper gear ring (10) and the external teeth of the lower gear ring (9) are machined. The first positioning marks are engraved on the upper gear ring (10) and the lower gear ring (9) respectively after the machining of the external teeth of the upper gear ring (10) and the external teeth of the lower gear ring (9) is completed; in step 1) above, when installing the upper gear ring (10), before the upper gear ring (10) meshes with multiple planet gears (22), the upper gear ring (10) is rotated through the position where the first positioning mark on the lower gear ring (9) is located. After the upper gear ring (10) meshes with multiple planet gears (22), the screw rod (252) of the jacking fixture (25) is rotated to make the two first positioning marks located on the upper gear ring (10) and the lower gear ring (9) correspond to each other, realizing the fine adjustment of the relative positions of the upper gear ring (10) and the lower gear ring (9), so that the circular runout error between the upper gear ring (10) and the lower gear ring (9) does not exceed 0.03 mm.

7. A method for assembling a speed reducer according to claim 1, characterized in that: In step 1) above, during the assembly process of the thrust head assembly, after the output shaft (1) is vertically lifted and moved to the workbench, the base (2), the bearing plate (33), the thrust head (6) and the thrust head spline sleeve (7) are successively sleeved on the output shaft (1). Then, multiple thrust bearing assemblies (4) are installed between the thrust head (6) and the bearing plate (33). Then, the bearing housing (3) is sleeved outside the thrust head and fixed on the base (2). Then, multiple guide bearing assemblies (5) are successively installed inside the bearing housing (3); among them, the top of the output shaft (1) is inserted into the thrust head spline sleeve (7), and the output shaft (1) and the thrust head spline sleeve (7) are in spline fit. The thrust head (6) and the thrust head spline sleeve (7) are fixed on the output shaft (1); during the assembly process of the thrust head assembly, with the output shaft of the calibration fixture (26) as the reference, the distances between the output shaft (1) and the base (2), the bearing plate (33) and the bearing housing (3) are measured, and the base (2), the bearing plate (33) and the bearing housing (3) are moved according to the results of the calibration fixture to make the output shaft (1), the base (2), the bearing plate (33) and the bearing housing (3) coaxial.

8. The assembly method of a speed reducer according to claim 7, characterized in that: The output shaft (1), the thrust head (6), and the spline sleeve (7) of the thrust head are all marked with corresponding second positioning marks. The second positioning marks are respectively marked on the output shaft (1), the thrust head (6), and the spline sleeve (7) of the thrust head after the output shaft (1), the thrust head (6), and the spline sleeve (7) are assembled and precisely ground before the assembly of the thrust head assembly; in the step 1), during the assembly of the thrust head assembly, the positions of the thrust head (6) and the spline sleeve (7) of the thrust head are adjusted through the second positioning mark on the output shaft (1), so that the relative positions of the second positioning marks respectively located on the output shaft (1), the thrust head (6), and the spline sleeve (7) after assembly are consistent with the relative positions of the three second positioning marks respectively located on the output shaft (1), the thrust head (6), and the spline sleeve (7) after the precision grinding is completed.

9. The assembly method of a speed reducer according to claim 7, characterized in that: Both the inner side and the outer side of the top of the bearing housing (3) have light-exposed sections (31). The light-exposed sections (31) are formed on the bearing housing (3) after the base (2) and the bearing housing (3) are installed together; in the step 1), when the bearing housing (3) is positioned, the distance between the light-exposed section (31) and the outer surface of the thrust head (6) is measured by the calibration tooling (26), and the position of the bearing housing (3) is adjusted according to the result of the calibration tooling (26) to make the bearing housing (3) coaxial with the thrust head (6).

10. A method for assembling a speed reducer according to claim 7, characterized in that: The calibration tooling (26) includes a depth gauge (261). The depth gauge includes an abutting portion (2611) and a measuring portion (2612) with scale marks. The measuring portion (2612) is slidably mounted on the abutting portion (2611). The abutting portion (2611) includes a measuring surface (26111) for abutting against the workpiece. The measuring surface (26111) includes an arc-shaped section for abutting against the outer cylindrical surface of the component.

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