A two-stage planetary gear reducer and its transmission structure

Abstract

The present invention relates to the technical field of reducers, specifically a two-stage planetary gear reducer and its transmission structure, including a primary sun gear, an inner ring gear, a primary planet set, a primary planet carrier, a secondary sun gear, a secondary planet set, and a secondary planet carrier, the primary sun gear serves as a primary input end, the secondary sun gear serves as a secondary input end, the primary sun gear and the secondary sun gear can both float and adjust the axial position, the primary planet carrier includes a base frame, a top frame and an adjustment frame, the base frame, the top frame and the adjustment frame rotate synchronously, the inner ring of the inner ring gear is fixedly connected to a positioning ring, the positioning ring is located between the top frame and the base frame, the surfaces of the base frame and the secondary planet carrier are both provided with a plurality of evenly distributed pins, the purpose of the present invention is to solve the problem that after the planet gear deviates downward, the line connecting the center of the planet gear and the center of the sun gear is no longer strictly horizontal.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a double-stage planetary gear reducer and a transmission structure thereof. Background Art

[0002] Planetary reducers are widely used industrial products that can reduce the speed of motors while increasing output torque. As a power transmission device connecting the power source and the actuator, they are indispensable in the transmission equipment field of industries such as lifting, excavation, transportation, construction, metallurgy, and industrial production.

[0003] The transmission structure of a traditional two-stage planetary gear reducer includes a first-stage input stage and a second-stage output stage planetary gear set, and adopts a coaxial and same-direction transmission design. In a vertically installed two-stage planetary gear reducer, the reducer axis is perpendicular to the ground, and the gravity direction of the planetary gear is consistent with the axis direction. Each planetary gear will be continuously affected by its own gravity, causing it to generate a downward static eccentric load on the planetary carrier pin shaft. The planetary gear is installed on the planetary carrier pin shaft through a bearing. Gravity will cause the center of the planetary gear to move slightly downward. After the planetary gear is offset downward, the line connecting its center and the center of the sun gear is no longer strictly horizontal, resulting in differences in the meshing angles of each planetary gear and the sun gear, and uneven load distribution. Summary of the Invention

[0004] The object of the present invention is to provide a two-stage planetary gear reducer and its transmission structure to solve the problem that after the planetary gear deviates downward, the line connecting the center of the planetary gear and the center of the sun gear is no longer strictly horizontal.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A two-stage planetary gear transmission structure includes a first-stage sun gear, an inner ring gear, a first-stage planet set, a first-stage planet carrier, a second-stage sun gear, a second-stage planet set, and a second-stage planet carrier. The first-stage sun gear serves as a first-stage input end, and the second-stage sun gear serves as a second-stage input end. Both the first-stage sun gear and the second-stage sun gear can be floated to adjust the axial position.

[0007] Preferably, the first-stage planetary frame includes a bottom frame, a top frame and an adjusting frame, and the bottom frame, the top frame and the adjusting frame rotate synchronously.

[0008] Preferably, the inner ring of the inner gear ring is fixedly connected to a positioning ring, and the positioning ring is located between the top frame and the bottom frame.

[0009] Preferably, the surfaces of the base frame and the secondary planetary carrier are both provided with a plurality of evenly distributed pins, and each of the pins is provided with an axially adjustable component.

[0010] Preferably, the first-stage planetary group includes a plurality of evenly distributed first planetary gears, and the second-stage planetary groups include a plurality of evenly distributed second planetary gears, and the first planetary gears and the second planetary gears are both connected to the pin shaft through an axially adjustable component.

[0011] Preferably, the first-stage planet carrier and the second-stage planet carrier are both equipped with force sensors, and the force sensors are used to monitor the load of the planetary gear.

[0012] Preferably, balls are provided on the contact surfaces between the positioning ring and the bottom frame and top frame.

[0013] A double-stage planetary gear reducer comprises the transmission structure and a casing, wherein the inner gear ring is fixedly connected to the inner wall of the casing.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The first and second sun gears adopt a floating structure, which can adjust the axial position and compensate for the axial deviation of the planet gears in real time, ensuring good meshing between gears, adjusting the load distribution, avoiding planet gear overload, significantly improving transmission smoothness, and reducing vibration and noise;

[0016] 2. The planetary gears are axially adjusted through axially adjustable components, and are combined with drum-shaped teeth or modified teeth to reduce edge contact stress, adapt to changes in meshing angle caused by slight axial offset, reduce power loss, and significantly improve transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the overall structure of the present invention;

[0018] Figure 2 This is a schematic structural diagram of the first-stage planet carrier of the present invention;

[0019] Figure 3 Schematic diagram of the structure of the planetary gear of the present invention;

[0020] Figure 4 It is a schematic diagram of the vertical cross-section structure of the axially adjustable component of the present invention.

[0021] In the figure: 1. Casing; 2. First-stage sun gear; 3. Hollow shaft; 4. Base frame; 5. Internal gear ring; 6. Second-stage sun gear; 7. Second-stage planetary gear; 8. Second-stage planetary carrier; 9. Fixing pin; 10. Positioning ring; 11. Linear guide column; 12. Top frame; 13. Adjustment frame; 14. Pin shaft. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] See also Figure 1 , the present invention provides a technical solution.

[0024] A two-stage planetary gear transmission structure includes a first-stage sun gear 2, an inner ring gear 5, a first-stage planetary set, a first-stage planetary carrier, a second-stage sun gear 6, a second-stage planetary set, and a second-stage planetary carrier 8. The first-stage sun gear 2 is rigidly connected to the motor input shaft through a flat key and serves as the first-stage power input end. The second-stage sun gear 6 serves as the second-stage input end. The first-stage planetary carrier is connected to the second-stage sun gear 6, and the second-stage planetary carrier 8 outputs. The transmission direction of the transmission structure is coaxial and directional with input and output. The first-stage sun gear 2 and the second-stage sun gear 6 both adopt a floating design, which can balance the load of each planetary gear and improve transmission stability. The first-stage planetary set includes three or four evenly distributed first planetary gears, which are mounted on the pin shaft 14 of the first-stage planetary carrier through an axially adjustable component and can rotate freely around its own axis. The first planetary gears are simultaneously engaged with the outer teeth of the first-stage sun gear 2 and the inner teeth of the inner ring gear 5 to form a planetary transmission pair;

[0025] The first-stage planet carrier serves as the output end of the first stage and is coaxially connected to the outer spline of the second-stage sun gear 6 through splines to transmit power to the second-stage transmission;

[0026] The secondary sun gear 6 is connected to the primary planet carrier. The secondary planetary set includes three or four evenly distributed second planetary gears 7, which are installed on the pin 14 of the secondary planet carrier 8 through an axially adjustable component. The structure is consistent with the first planetary gear. The second planetary gears 7 are simultaneously engaged with the external teeth of the secondary sun gear 6 and the internal teeth of the inner ring gear 5 to form a secondary planetary transmission pair. The secondary planet carrier 8 serves as the output end of the system and is rigidly connected to the load through a flange to transmit torque to the external actuator.

[0027] The first-stage planetary carrier includes a base frame 4, a top frame 12 and an adjusting frame 13. The base frame 4, the top frame 12 and the adjusting frame 13 rotate synchronously. The base frame 4 and the top frame 12 are firmly connected with the help of a fixing pin 9 to construct the basic framework of the first-stage planetary carrier. The adjusting frame 13 and the top frame 12 are floatingly connected. The adjusting frame 13 is coaxially connected to the secondary sun gear 6. The adjusting frame 13 can float flexibly, thereby driving the secondary sun gear 6 to adjust the axial position, thereby realizing adaptive adjustment of the axial offset of the planetary gear.

[0028] The base frame 4 serves as the basic supporting component of the first-level planetary frame. It is made of high-strength alloy steel to withstand the large load generated by the reducer during operation. It is circular in shape and has a pin 14 for installing the first planetary gear. Several through holes matching the fixing pins 9 are evenly distributed on the edge of the base frame 4 for connecting with the top frame 12. The secondary planetary frame 8 also has a pin 14 for installing the second planetary gear 7. The installation method of the second planetary gear 7 is the same as that of the first planetary gear.

[0029] The top frame 12 is located above the bottom frame 4 and is also made of high-strength alloy steel. Its shape echoes the bottom frame 4 and is a circular structure. A central through hole is provided at the center of the adjustment frame 13 to accommodate the top frame 12. A linear guide column 11 is provided around the central through hole on the upper surface of the top frame 12. The top frame 12 corresponds to the position of the through hole on the edge of the bottom frame 4 and is provided with corresponding threaded holes so that it can be connected to the bottom frame 4 through a fixing pin 9.

[0030] The adjustment frame 13 is the core component for realizing the axial position adjustment function. Its main body is a disc-shaped structure. The outer diameter of the disc is equal to the outer diameter of the base frame 4. The adjustment frame 13 is connected to the secondary sun gear 6 through a spline connection, which can not only transmit torque but also drive the secondary sun gear 6 to move axially.

[0031] The fixing pin 9 adopts a high-strength bolt, the specification of which is selected according to the load-bearing capacity and size of the reducer. The length of the bolt must ensure that it can firmly connect the base frame 4 and the top frame 12. At the same time, after tightening, it must be ensured that there is sufficient pre-tightening force to prevent loosening during the operation of the reducer.

[0032] When axial deviation of the planetary gear is found, the adjusting frame 13 is driven to move axially. Since the secondary sun gear 6 is connected to the adjusting frame 13, the secondary sun gear 6 is driven to move up and down, forming a floating connection between the adjusting frame 13 and the top frame 12. In this way, the secondary sun gear 6 can automatically adjust its axial position to adapt to the axial deviation of the planetary gear, ensure normal engagement between the gears, and evenly distribute the load on each planetary gear, thereby improving the transmission performance and stability of the reducer.

[0033] Please refer to Figure 2, an embodiment of driving the adjustment frame 13 to move axially adopts a screw pair structure, the surface thread of the top frame 12 is penetrated and connected with a screw, one end of the screw is rotatably connected to the adjustment frame 13, and the axial movement of the screw is achieved by rotating the screw and the threaded action between the screw and the top frame 12. The movement of the screw drives the adjustment frame 13 to move axially. By setting a position sensor (such as a linear potentiometer) on the screw, the displacement of the adjustment frame 13 is fed back in real time to form a closed-loop control to ensure the axial adjustment accuracy. The adjustment frame 13 can also be directly connected to the sun gear shaft end flange by bolts to ensure that the two move axially synchronously. Two groups of symmetrically distributed linear guide columns 11 are set on the top frame 12, and linear bearings or sliders are installed at the corresponding positions of the adjustment frame 13 to form an axial sliding pair to limit radial offset (precision control The adjustment frame 13 is provided with mechanical limit blocks at both ends of the stroke, and is equipped with proximity switches to prevent gear disengagement or jamming caused by excessive adjustment. The sun gear and the planetary gear use drum-shaped teeth or modified teeth to reduce edge contact stress and adapt to changes in meshing angle caused by slight axial offset. The adjustment frame 13 and the top frame 12 are made of high-strength aluminum alloy (such as 7075) or quenched and tempered steel (such as 42CrMo). The linear guide column 11 is surface-hardened (hardness HRC55-60) to improve wear resistance. The first-stage planetary carrier and the second-stage planetary carrier 8 are both equipped with force sensors, which are used to monitor the load of the planetary gear. When the load of a planetary gear exceeds the limit directly monitored by the force sensor (such as a piezoresistive microsensor), the axial position of the sun gear or the planetary gear needs to be adjusted.

[0034] The floating design of the adjustment frame 13 enables the secondary sun gear 6 to adjust its position according to the actual axial offset of the planetary gears, thereby improving the automation and reliability of the speed reducer.

[0035] By timely adjusting the axial position of the secondary sun gear 6, good meshing between gears is ensured, and the power loss caused by axial offset is reduced, thereby improving the transmission efficiency of the speed reducer.

[0036] Uniform load distribution reduces local wear between gears, while also reducing vibration and noise caused by poor meshing, extending the service life of the gears and improving the working environment.

[0037] The inner ring of the inner gear ring 5 is fixedly connected with a positioning ring 10, which is located between the top frame 12 and the bottom frame 4. By setting the positioning ring 10, it is beneficial to fix the axial position of the bottom frame 4 and the top frame 12. When installing the bottom frame 4 and the top frame 12, first place the top frame 12 on the upper end of the positioning ring 10, and then place the bottom frame 4 on the lower end of the positioning ring 10, and then connect and fix it with a fixing pin. Since the bottom frame 4 and the top frame 12 will rotate, in order to reduce the friction with the positioning ring 10, balls are set on the contact surface of the positioning ring 10 and the bottom frame 4 and the top frame 12 to convert sliding friction into rolling friction.

[0038] The axial position of the primary sun gear 2 can be adjusted in the same manner as that of the secondary sun gear 6 .

[0039] The surfaces of the base frame 4 and the secondary planetary carrier 8 are both provided with a plurality of evenly distributed pins 14, and each pin 14 is provided with an axially adjustable component to realize independent or synchronous axial adjustment of the planetary gears to ensure the axial alignment of the planetary gears. The axially adjustable component includes a hollow shaft 3, an adjusting nut and a locking nut. Each planetary gear is connected to the hollow shaft 3 through a bearing. The hollow shaft 3 is sleeved on the pin 14, and an adjusting nut is provided on the inner ring surface of the hollow shaft 3. The surface of the pin 14 is processed with an external thread, and the pin 14 is movable through the adjusting nut and is threadedly connected to the adjusting nut. A locking nut is configured at the bottom end of the pin 14, and the locking nut is threadedly connected to the pin 14. The hollow shaft 3 is locked by pressing the locking nut against the hollow shaft 3.

[0040] A double-stage planetary gear reducer includes a transmission structure and a housing 1. The housing 1 is split and includes a front cover, a middle cover, and a rear cover, which are connected by bolts to ensure coaxiality. An inner gear ring 5 is fixed to the housing 1.

[0041] The specific solution is as follows: the input shaft drives the first-stage sun gear 2 to rotate, the first planetary gear revolves and rotates, driving the first-stage planetary carrier to rotate, the first-stage planetary carrier drives the second-stage sun gear 6, and then the second planetary gear 7 revolves to drive the second-stage planetary carrier 8 to output low speed and high torque.

[0042] Place the top frame 12 on the upper end of the positioning ring 10, and the bottom frame 4 on the lower end of the positioning ring 10, so that the through hole on the edge of the bottom frame 4 is aligned with the threaded hole of the top frame 12, and use the fixing pin 9 to pass through the through hole and the threaded hole for connection. Tighten the bolts according to the specified torque to ensure that the bottom frame 4 and the top frame 12 are firmly connected to form the basic framework of the first-level planetary frame. Install the three first planetary gears on the pin shaft 14 of the bottom frame 4 through the bearing, and ensure that the planetary gears can rotate freely around their own axes. Check that the bearings are installed in place and there is no skew. Fix the inner ring gear 5 in the casing 1, ensure that the installation position of the inner ring gear 5 and the casing 1 is accurate, and ensure that the first planetary gear is simultaneously aligned with the outer teeth of the first-level sun gear 2 and the inner ring gear 5. The teeth mesh to form a planetary transmission pair. Check the meshing clearance to ensure that it is within the design allowable range (generally 0.1-0.3mm). Securely connect them using bolts or other fixing methods familiar to those skilled in the art. Connect the adjustment frame 13 coaxially to the secondary sun gear 6 to ensure that torque can be transmitted and drive the secondary sun gear 6 to move axially. Install the three second planetary gears 7 on the pin 14 of the secondary planetary carrier 8 through bearings. Make sure that the second planetary gears 7 simultaneously mesh with the external teeth of the secondary sun gear 6 and the internal teeth of the inner ring gear 5 to form a secondary planetary transmission pair. Use the secondary planetary carrier 8 as the system output end and rigidly connect it to the load through a flange to ensure that the flange connection is firm and the coaxiality meets the requirements.

[0043] Turn on the motor power supply and conduct a no-load test run. Start from a low speed and gradually increase the running speed to the rated speed. The running time should be no less than 30 minutes. Monitor the vibration and noise during the operation. The vibration amplitude should not exceed 5mm / s and the noise decibel should not exceed 85dB (A). If any abnormality is found, stop the machine to check the gear meshing condition, bearing installation, etc. If the force sensor finds that the load of a planetary gear exceeds the limit, manually operate the screw to drive the adjusting frame 13 to move axially, adjust the axial position of the secondary sun gear 6, and make the load evenly distributed.

[0044] The axial position of the first-stage sun gear 2 is adjusted in the same way as the second-stage sun gear 6. It is adjusted according to the load conditions of the planetary gears. The axial position of the planetary gears is adjusted by rotating the hollow shaft 3 and adjusting the threaded action between the nut and the pin shaft 14 to make the hollow shaft 3 move axially to realize the movement of the axial position of the planetary gear. After the adjustment is completed, the locking nut is tightened and the hollow shaft 3 is pressed against to lock it, ensuring that the planetary gears are axially aligned. Turn on the motor power supply and start the motor according to the prescribed starting sequence. The input shaft drives the first-stage sun gear 2 to rotate. The first planetary gear revolves around the first-stage sun gear 2 and rotates on its own axis, pushing the first-stage planet carrier to rotate. The first-stage planet carrier drives the second-stage sun gear 6. Then the second planetary gear 7 revolves to drive the second-stage planet carrier 8 to output low speed and high torque. During operation, ensure that the transmission direction is coaxial and in the same direction as the input and output, and there is no abnormal deviation. Check the connecting bolts of each component every quarter, such as the connecting bolts between the base frame 4 and the top frame 12, the connecting bolts of the various parts of the casing 1, etc. Use a torque wrench to retighten them according to the specified torque to prevent loosening.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A two-stage planetary gear transmission structure, comprising a primary sun gear (2), an inner ring gear (5), a primary planetary set, a primary planetary carrier, a secondary sun gear (6), a secondary planetary set, and a secondary planetary carrier (8), characterized in that: The first-stage sun gear (2) serves as a first-stage input end, and the second-stage sun gear (6) serves as a second-stage input end. Both the first-stage sun gear (2) and the second-stage sun gear (6) can be floated to adjust their axial positions. The first-stage planetary frame comprises a bottom frame (4), a top frame (12) and an adjusting frame (13); the bottom frame (4), the top frame (12) and the adjusting frame (13) rotate synchronously; the adjusting frame (13) is coaxially connected to the second-stage sun gear (6); the adjusting frame (13) can float flexibly, thereby driving the second-stage sun gear (6) to adjust its axial position; The inner ring of the inner gear ring (5) is fixedly connected to a positioning ring (10), and the positioning ring (10) is located between the top frame (12) and the bottom frame (4); The surfaces of the base frame (4) and the secondary planetary frame (8) are both provided with a plurality of evenly distributed pins (14), and each pin (14) is provided with an axially adjustable component.

2. A two-stage planetary gear transmission structure according to claim 1, characterized in that: The first-stage planetary group includes a plurality of evenly distributed first planetary gears, and the second-stage planetary groups each include a plurality of evenly distributed second planetary gears (7), and the first planetary gears and the second planetary gears (7) are both connected to the pin shaft (14) via an axially adjustable component.

3. The double-stage planetary gear transmission structure according to claim 1, characterized in that: The first-stage planet carrier and the second-stage planet carrier (8) are both equipped with force sensors, and the force sensors are used to monitor the load of the planetary gears.

4. The double-stage planetary gear transmission structure according to claim 1, characterized in that: Ball bearings are provided on the contact surfaces of the positioning ring (10) with the bottom frame (4) and the top frame (12).

5. A two-stage planetary gear reducer, characterized in that: It comprises the transmission structure according to claim 1 and a housing (1), wherein the inner gear ring (5) is fixedly connected to the inner wall of the housing (1).

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