Planetary gear shaft anti-disengagement structure and method

Abstract

This invention relates to the field of planetary gear technology, specifically to a structure and method for preventing planetary gear shaft detachment. By creating coaxial first and second holes on the planet carrier and planetary gear shaft respectively, an elastic cylindrical pin is inserted into both holes, utilizing its elasticity to provide radial force for radial fastening. A limiting ring prevents the elastic cylindrical pin from detaching, and a clearance fit between a limiting groove and a limiting protrusion further restricts its movement and rotation. The staggered arrangement of the grooves creates a reverse clamping force when the elastic cylindrical pin spirals up, forming a multi-limiting mechanism. This invention absorbs impact through an elastic structure, avoiding the rapid failure problem of traditional fixing methods and improving limiting reliability; it also requires fewer parts and has a simpler manufacturing process.

Description

Technical Field

[0001] This invention relates to the field of planetary gear technology, and specifically to a planetary gear shaft anti-detachment structure and method. Background Technology

[0002] Planetary gears are a type of gear transmission mechanism consisting of a central gear (sun gear), planet gears, a planet carrier, and an internal gear ring. With their core advantages of large transmission ratio, compact structure, strong load-bearing capacity, and high transmission efficiency, they are widely used in various mechanical systems that require deceleration, speed increase, differential speed, or power distribution.

[0003] During planetary gear assembly, a connection must be established between the coaxially aligned planetary gear shaft and the planetary carrier. Effective axial positioning of the planetary gear shaft is crucial to prevent axial movement and ensure stable planetary gear operation. Traditional positioning techniques commonly involve embedding elastic retaining rings (circlips), round nuts, or thrust washers into the planetary carrier's grooves. Axial positioning of the planetary gear shaft is achieved through the elastic deformation of these components. However, such structures have relatively low strength and can only withstand small axial forces, making them prone to failure under heavy loads, impacts, and other complex conditions. Other techniques use bolts or pins for fixing. While this improves axial load capacity, the impact vibrations generated during planetary gear operation are directly transmitted to the bolts or pins, easily leading to loosening and affecting the reliability of the positioning.

[0004] In summary, existing planetary gear shaft limiting technology still has significant shortcomings and cannot guarantee the reliability of the limiting. Summary of the Invention

[0005] This invention provides a planetary gear shaft anti-disengagement structure and method to solve the problem of difficulty in ensuring the reliability of the limit in existing planetary gear shaft limiting technology.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] On the one hand, a planetary gear shaft anti-disengagement structure is provided, comprising:

[0008] The first hole is located on the planet carrier and extends through the planet gear shaft mounting area.

[0009] The second hole is made on the planetary gear shaft. After the planetary gear shaft is installed in the installation area, the second hole is coaxial with the first hole.

[0010] The flexible cylindrical pin is made of spring steel and is interference-fitted into the first hole and the second hole. The flexible cylindrical pin provides radial force to the sidewalls of the first hole and the second hole.

[0011] A limiting ring is fixedly connected to the side of the first hole near the outer circumference of the planetary carrier. The inner diameter of the limiting ring is smaller than the diameter of the elastic cylindrical pin that is interference-fitted in the first and second holes.

[0012] Furthermore, there is a gap between the end face of the limiting ring near the elastic cylindrical pin and the end face of the elastic cylindrical pin near the limiting ring.

[0013] Furthermore, a limiting groove is provided on the inner sidewall of the first hole and / or the inner sidewall of the second hole, and a limiting protrusion is provided on the sidewall of the elastic cylindrical pin. When the elastic cylindrical pin is interference-fitted in the first hole and the second hole, the limiting protrusion is located in the limiting groove, and the limiting protrusion and the limiting groove are clearance-fitted.

[0014] Furthermore, both the inner walls of the first and second holes are provided with limiting grooves, and the sidewalls of the elastic cylindrical pin are provided with limiting protrusions corresponding to the position and number of the limiting grooves.

[0015] Furthermore, the first hole includes a first outer section, and the second hole includes a second outer section; both the first outer section and the second outer section are provided with limiting grooves, and the limiting groove located in the first outer section and the limiting groove located in the second outer section are not at the same height.

[0016] Furthermore, the first hole also includes a first inner section, and the second hole also includes a second inner section; both the first inner section and the second inner section are provided with limiting grooves, and the limiting groove located in the first inner section and the limiting groove located in the second inner section are not at the same height.

[0017] Furthermore, the limiting grooves located in the second outer section and the second inner section are at the same height, and the limiting grooves located in the first outer section and the first inner section are at the same height.

[0018] Furthermore, the projections of the limiting grooves are arranged in pairs on the same radial line of the first hole or the second hole; the elastic cylindrical pin is a spirally wound elastic cylindrical pin, which is spirally wound when subjected to external force, and the maximum diameter of the elastic cylindrical pin in the unwound state is greater than the diameter of the first hole and the second hole.

[0019] Further, the assembly method of the elastic cylindrical pin is as follows: clamp the elastic cylindrical pin so that the maximum diameter of the elastic cylindrical pin is less than or equal to the inner diameter of the limiting ring, pass the elastic cylindrical pin through the limiting ring, the first hole and the second hole in sequence, release the elastic cylindrical pin, push the remaining elastic cylindrical pin outside the limiting ring completely into the first hole and the second hole, rotate the fine-tuning elastic cylindrical pin so that the limiting protrusion is located in the limiting groove.

[0020] Method for disassembling the elastic cylindrical pin: Rotate and push the elastic cylindrical pin outward to disengage the limiting protrusion from the limiting groove. The elastic cylindrical pin remains in a compressed state. Continue to push the elastic cylindrical pin outward until it is completely outside the limiting ring.

[0021] On the other hand, a method for preventing planetary gear shaft from detaching is provided, which is aimed at the above-mentioned planetary gear shaft anti-detachment structure, including: installing the planetary gear shaft onto the mounting area on the planet carrier, passing through the limiting ring, and inserting an elastic cylindrical pin into the first hole and the second hole until the elastic cylindrical pin is completely located in the first hole and the second hole inside the limiting ring, and the elastic cylindrical pin provides radial force to the sidewalls of the first hole and the second hole.

[0022] The technical principles of the above solution are as follows:

[0023] This invention achieves radial fastening between the planetary gear shaft and the planetary carrier by creating a first hole through the planetary carrier and a second hole coaxial with the first hole on the planetary gear shaft. A flexible cylindrical pin passes through the second hole with both ends placed inside the first hole. The elastic restoring force of the flexible cylindrical pin applies a continuous radial force to the sidewalls of the first and second holes. Simultaneously, a limiting ring is placed on the side of the first hole near the outer circumference of the planetary carrier. The inner diameter of this ring is smaller than the maximum natural diameter of the flexible cylindrical pin, forming an axial anti-disengagement barrier to prevent the flexible cylindrical pin from coming out of the first hole.

[0024] Furthermore, by opening limiting grooves on the inner sidewalls of the first hole and / or the second hole, and setting matching limiting protrusions on the sidewalls of the elastic cylindrical pin, the axial movement and circumferential rotation of the elastic cylindrical pin in the hole are restricted by the clearance fit between the limiting protrusions and the limiting grooves; and by staggering the limiting grooves of different hole sections, when the elastic cylindrical pin is subjected to bending moment and torque and generates spiral winding, a reverse clamping force is formed between the limiting protrusions and the limiting grooves, which further counteracts the axial movement tendency of the planetary gear shaft.

[0025] The elastic cylindrical pin adopts a spiral winding structure. When subjected to external force, it undergoes spiral winding deformation. After the external force disappears, it relies on its own elasticity to recover radial force, which not only ensures compressibility during assembly, but also provides a stable fastening force continuously during operation. Combined with the physical blocking of the limiting ring and the biting limiting of the limiting groove and the limiting protrusion, a triple limiting mechanism of radial fastening, axial anti-disengagement and circumferential anti-rotation is formed.

[0026] The above approach has the following beneficial effects:

[0027] 1. This solution uses the radial elastic force of the elastic cylindrical pin to fasten the planetary gear shaft to the planetary carrier. Combined with the physical limiting ring, it replaces the traditional fixing methods such as snap rings and bolts. The elastic cylindrical pin can absorb the impact vibration during the operation of the planetary gear through its own elastic deformation, avoiding failure problems such as snap ring breakage and bolt loosening. It greatly improves the stability and reliability of the planetary gear shaft limiting, and is especially suitable for complex working conditions with heavy load and strong vibration.

[0028] 2. The anti-detachment structure of this solution consists only of an elastic cylindrical pin, a limiting ring, and a matching hole and groove structure. Compared with the existing technology, it has fewer parts and a simpler processing technology, and does not require the addition of a large number of precision positioning pins or complex assembly tooling.

[0029] 3. This solution designs a suitable method for assembling and disassembling the elastic cylindrical pin. Assembly can be completed by clamping the elastic cylindrical pin to make it roll up, and disassembly can be achieved by rotating and squeezing the elastic cylindrical pin. The operation steps are simple, no special tools are required, and the efficiency of disassembly and maintenance of planetary gear shafts is greatly improved.

[0030] 4. This solution, through the staggered arrangement of limiting grooves and limiting protrusions, causes the elastic cylindrical pin to generate a reverse clamping force when it is spirally wound by external force. This not only counteracts the tendency of the planetary gear shaft to move, but also disperses stress concentration, reduces the slippage and wear between the elastic cylindrical pin and the hole wall, extends the overall service life of the anti-detachment structure, and reduces the frequency of later maintenance of the equipment. Attached Figure Description

[0031] Figure 1 This is an isometric view of a planetary gear set according to an embodiment of the present invention;

[0032] Figure 2 This is an exploded view of the star gear assembly according to an embodiment of the present invention;

[0033] Figure 3 This is a top view of the star gear assembly according to an embodiment of the present invention;

[0034] Figure 4 for Figure 3 AA sectional view;

[0035] Figure 5 This is an isometric view of a planetary carrier according to an embodiment of the present invention;

[0036] Figure 6 This is a top view of the planetary carrier according to an embodiment of the present invention;

[0037] Figure 7 for Figure 6 BB cross-sectional diagram;

[0038] Figure 8 A schematic diagram of the elastic cylindrical pin shaft according to an embodiment of the present invention;

[0039] Figure 9 This is an isometric view of the planetary gear shaft according to an embodiment of the present invention;

[0040] Figure 10 This is a top view of the planetary gear shaft according to an embodiment of the present invention;

[0041] Figure 11 for Figure 10 CC cross-sectional view;

[0042] Figure 12 This is a partial sectional view of an anti-detachment structure under an elastic cylindrical pin installation method according to an embodiment of the present invention;

[0043] Figure 13 for Figure 12 A magnified schematic diagram of part D;

[0044] Figure 14 This is a schematic diagram illustrating the working principle of the anti-detachment structure in an embodiment of the present invention;

[0045] Figure 15 This is a partial sectional view of the anti-detachment structure under another elastic cylindrical pin installation method according to an embodiment of the present invention;

[0046] Figure 16 for Figure 15 A magnified view of part E;

[0047] Figure 17 This is a partial sectional view of the anti-detachment structure under another elastic cylindrical pin installation method according to an embodiment of the present invention;

[0048] Figure 18 for Figure 17 A magnified schematic diagram of part F.

[0049] The reference numerals in the accompanying drawings include: 11, planetary carrier; 12, planetary gear; 13, planetary gear shaft; 14, second hole; 141, second outer section; 142, second inner section; 15, needle roller bearing; 16, elastic cylindrical pin; 161, limiting protrusion; 162, limiting groove; 17, first hole; 171, first outer section; 172, first inner section; 18, limiting ring. Detailed Implementation

[0050] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] The following detailed description illustrates the specific implementation method:

[0054] like Figure 1 The figure shown is an isometric view of a planetary gear set with the anti-disengagement structure of the planetary gear shaft in this embodiment (hereinafter referred to as the anti-disengagement structure). The central gear and its accessory structure are not shown. This embodiment uses the planetary gear set to describe the anti-disengagement structure in detail.

[0055] like Figure 2 The diagram shown is an exploded view of a planetary gear set. The planetary gear set mainly consists of a planet carrier 11, planetary gears 12, needle roller bearings 15, and planetary gear shafts 13. The planet carrier 11 has planetary gear shaft holes, which serve as the mounting areas for the planetary gear shafts 13 and are arranged circumferentially around the axis of the planet carrier 11. The planet carrier 11 has mounting spaces for the planetary gears 12. Needle roller bearings 15 are fitted onto the planetary gear shafts 13, and the planetary gears 12 are then fitted onto the needle roller bearings 15. Both the needle roller bearings 15 and the planetary gears 12 are assembled within the mounting spaces for the planetary gears 12. An anti-detachment structure further limits and fixes the planetary gear shafts 13, thus forming the basic planetary gear set structure.

[0056] like Figure 3 The image shows a top view of the planetary gear set. After assembly, the planetary gears 12 in the planetary gear set extend to the middle area of ​​the planet carrier 11. This area is where the central gear and its accessories are located. The assembled central gear meshes with the surrounding planetary gears 12. By rotating the central gear, the planetary gears 12 can be driven to rotate synchronously, thereby driving the planet carrier 11 to rotate.

[0057] like Figure 4 As shown, Figure 3 A cross-sectional view of the planetary gear set (AA section). The anti-disengagement structure includes a first hole 17 and a second hole 14. The first hole 17 is formed in the planet carrier 11, and the second hole 14 is formed in the planetary gear shaft 13. Both holes have the same diameter and are conventional cylindrical holes. The first hole 17 passes through the mounting area of ​​the planetary gear shaft 13, and the second hole 14 passes through the planetary gear shaft 13. The planetary gear shaft 13, which is installed in the mounting area, is coaxial with the planetary gear shaft hole in the planet carrier 11; at the same time, the first hole 17 and the second hole 14 are also coaxial.

[0058] like Figure 5 and Figure 6 The figures shown are an isometric view and a top view of the planet carrier 11, respectively. A non-detachment structure is provided for a flexible cylindrical pin mounting method: the first hole 17 is divided into two parts, located on the side walls of the planet gear shaft hole, with the part located on the outer side of the planet carrier 11 penetrating the planet carrier 11. (See figure) Figure 7 As shown, Figure 6 A BB cross-sectional view of the planetary carrier 11; the anti-detachment structure also includes a limiting ring 18. Referring to the illustration, in this embodiment, the limiting ring 18 is integrally formed with the planetary carrier 11 and is located within the first hole 17 near the outer periphery of the planetary carrier 11. Figures 2-4 and Figures 12-14 As shown, it also includes an elastic cylindrical pin 16, with a second hole 14 that passes through the planetary gear shaft 13. The elastic cylindrical pin 16 completely passes through the second hole 14, and the length of the elastic cylindrical pin 16 is greater than that of the second hole 14. Both ends of the elastic cylindrical pin 16 extend into the first hole 17. In this embodiment, both ends of the elastic cylindrical pin 16 extend into the first hole 17. After the elastic cylindrical pin 16 is installed into the first hole 17 and the second hole 14, it is completely located inside the limiting ring 18.

[0059] In some other embodiments, a rivet stud is riveted to the limiting ring 18 to block the first hole 17, further preventing the elastic cylindrical pin 16 from disengaging. For those skilled in the art, a common needle roller can also be used instead of the elastic cylindrical pin 16; with the above-described structure, the needle roller is also less likely to disengage from the first hole 17 and the second hole 14.

[0060] Some other embodiments provide an anti-detachment structure under another flexible cylindrical pin mounting method: combined with Figure 15 and Figure 16 As shown, the first hole 17 is part of the planet carrier 11; the second hole 14 penetrates the planet gear shaft 13; the elastic cylindrical pin 16 is longer than the second hole 14; one end of the elastic cylindrical pin 16 completely penetrates the planet gear shaft 13 and extends into the first hole 17.

[0061] Some other embodiments also provide an anti-detachment structure under another flexible cylindrical pin mounting method: combined with Figure 17 and Figure 18 As shown, the first hole 17 is part of the planet carrier 11 and is located on the outside of the planet carrier 11; the second hole 14 is located only on one side of the planet gear shaft 13, one end of the elastic cylindrical pin 16 is located in the second hole 14 and extends to the middle of the planet gear shaft 13, and the other end of the elastic cylindrical pin 16 extends into the first hole 17.

[0062] This embodiment mainly describes in detail the improved elastic cylindrical pin 16, the second hole 14 that passes through the planetary gear shaft 13, the elastic cylindrical pin 16 that completely passes through the second hole 14, the two ends of the elastic cylindrical pin 16 that extend into the first hole 17, and the anti-detachment structure that is divided into two parts and located on the side walls of the planetary gear shaft hole, so as to achieve the best anti-detachment effect of the anti-detachment structure.

[0063] like Figure 8 The figure shows an isometric view of the elastic cylindrical pin 16. In this embodiment, the elastic cylindrical pin 16 is rolled from spring steel (65Mn). The diameter of different parts of the rolled elastic cylindrical pin 16 varies slightly. The largest diameter of the elastic cylindrical pin 16 must be greater than the diameter of the first hole 17 and the second hole 14. Preferably, the diameter of each part of the elastic cylindrical pin 16 is greater than the diameter of the first hole 17 and the second hole 14 to ensure an interference fit with the first hole 17 and the second hole 14 after insertion, providing a stable radial force to the sidewalls of the second hole 14 and the first hole 17. In some other embodiments, the elastic cylindrical pin 16 has chamfers at both ends, and chamfers are also provided at the opening end of the first hole 17 and the opening end of the limiting ring 18. During assembly, it is convenient for the elastic cylindrical pin 16 to be inserted into the first hole 17 and the second hole 14 through the limiting ring 18.

[0064] Based on the above structure, the elastic cylindrical pin 16 is compressed to a smaller diameter and then inserted into the first hole 17 and the second hole 14 through the limiting ring 18. After the elastic cylindrical pin 16 is accurately installed, there is a gap between the end face of the limiting ring 18 near the elastic cylindrical pin 16 and the end face of the elastic cylindrical pin 16 near the limiting ring 18. After the compressive force is released, the elastic cylindrical pin 16 generates and maintains a radial force on the sidewalls of the first hole 17 and the second hole 14, thereby limiting and fixing the planetary gear shaft 13. The radial force of the elastic cylindrical pin 16 on the sidewall of the first hole 17 allows it to be stably fixed in the first hole 17 and stably connected to the planet carrier 11; at the same time, the radial force of the elastic cylindrical pin 16 on the sidewall of the second hole 14 allows it to be stably connected to the planetary gear shaft 13; and with the limiting effect of the limiting ring 18, the elastic cylindrical pin 16 can be prevented from dislodging from the first hole 17; through the above-mentioned fastening and limiting effect, the elastic cylindrical pin 16 in this embodiment is not easy to loosen, and the limiting reliability is strong. When the planetary gear set is running, the impact vibration generated is transmitted to the elastic cylindrical pin 16. Since the elastic cylindrical pin 16 has a coiling force, it will coil slightly after being squeezed by external forces such as impact vibration. However, it always has a radial force on the sidewalls of the first hole 17 and the second hole 14. The radial force in the opposite direction to the impact vibration force can promote the reset of the planetary gear shaft 13 that has moved. Under complex working conditions such as impact, it still has a strong limiting and anti-axial movement ability.

[0065] Although the anti-detachment structure of the above embodiment improves the limiting and anti-axial movement capabilities compared to existing structures during actual operation, the duration of maintaining strong limiting and anti-axial movement capabilities is limited. Because the elastic cylindrical pin 16 of the above embodiment is rolled, when subjected to external force, the elastic cylindrical pin 16 is rolled up as a whole, and the overall diameter is reduced. This causes the radial force of the elastic cylindrical pin 16 in a certain area within the first hole 17 and the second hole 14 to fail instantly, which can easily lead to the elastic cylindrical pin 16 moving axially along the first hole 17 and the second hole 14. This accelerates the wear of the surface of the first hole 17, the second hole 14, or the elastic cylindrical pin 16, causing the radial force of the elastic cylindrical pin 16 on the sidewalls of the first hole 17 and the second hole 14 to gradually weaken until it fails. Consequently, the limiting and anti-axial movement capabilities gradually weaken until they fail. For example, when the planetary gear shaft 13 moves upward, the elastic cylindrical pin 16 is squeezed and coiled, reducing its overall diameter. This increases the radial force acting on the top region of the first hole 17, while decreasing or eliminating the radial force acting on the bottom region of the first hole 17. Similarly, it decreases or eliminates the radial force acting on the top region of the second hole 14, while increasing the radial force acting on the bottom region of the second hole 14. To extend the service life of the anti-detachment structure in the above embodiment, the following improved embodiment is proposed:

[0066] like Figures 8-11 As shown, in the first improved embodiment, a limiting groove 162 is formed on the inner sidewall of the first hole 17, and a limiting protrusion 161 is integrally formed on the sidewall of the elastic cylindrical pin 16. The position and number of the limiting protrusions 161 correspond to the limiting groove 162. The limiting groove 162 is a flat-bottomed U-shaped groove with a certain width along the arc direction, and the limiting protrusion 161 is an arc-shaped top protrusion. After the elastic cylindrical pin 16 is installed in place, the limiting protrusion 161 is located in the limiting groove 162 and has a clearance fit with it. In this embodiment, the relative displacement between the elastic cylindrical pin 16 and the first hole 17 is reduced by the limiting protrusion 161 and the limiting groove 162.

[0067] In the second improved embodiment, a limiting groove 162 is formed on the inner sidewall of the second hole 14, and a limiting protrusion 161 is integrally formed on the sidewall of the elastic cylindrical pin 16. The position and number of the limiting protrusions 161 correspond to the limiting groove 162. The limiting groove 162 is also a flat-bottomed U-shaped groove with a certain width along the arc direction, and the limiting protrusions 161 are arc-shaped top protrusions. After the elastic cylindrical pin 16 is installed in place, the limiting protrusions 161 are located in the limiting groove 162 and are in clearance fit with it. In this embodiment, the relative displacement between the elastic cylindrical pin 16 and the second hole 14 is reduced by the limiting protrusions 161 and the limiting groove 162.

[0068] In the third improved embodiment, limiting grooves 162 are formed on the inner sidewalls of both the first hole 17 and the second hole 14, and limiting protrusions 161 are integrally formed on the sidewalls of the elastic cylindrical pin 16. The position and number of the limiting protrusions 161 correspond to the limiting grooves 162. The limiting grooves 162 are also flat-bottomed U-shaped grooves with a certain width along the arc direction, and the limiting protrusions 161 are arc-shaped top protrusions. After the elastic cylindrical pin 16 is installed in place, the limiting protrusions 161 are located within the limiting grooves 162 and are in clearance fit with them. In this embodiment, the relative displacement between the elastic cylindrical pin 16 and the first hole 17 and the second hole 14 is reduced by the limiting protrusions 161 and the limiting grooves 162.

[0069] Based on the above, a preferred embodiment is proposed, wherein limiting grooves 162 are formed on the inner sidewalls of both the first hole 17 and the second hole 14, and the limiting protrusions 161 are clearance-fitted with the corresponding limiting grooves 162. This embodiment further divides the first hole 17 into a first outer segment 171 and a first inner segment 172, and the second hole 14 into a second outer segment 141 and a second inner segment 142. One implementation is to distribute the limiting grooves 162 on the first outer segment 171 and the second outer segment 141; another implementation is to distribute the limiting grooves 162 on the first inner segment 172 and the second inner segment 142; a preferred implementation is that limiting grooves 162 are provided on the first outer segment 171, the second outer segment 141, the first inner segment 172, and the second inner segment 142.

[0070] To avoid stress concentration caused by the limiting areas acting on the elastic cylindrical pin 16 being located in adjacent areas on the same side, a preferred embodiment is to set the limiting groove 162 of the first outer segment 171 and the limiting groove 162 located in the second outer segment 141 at different heights, and to set the limiting groove 162 of the first inner segment 172 and the limiting groove 162 located in the second inner segment 142 at different heights, thereby dispersing stress. Figure 12 and Figure 13 As shown, in this embodiment, a limiting groove 162 is provided on the first outer segment 171, the second outer segment 141, the first inner segment 172, and the second inner segment 142 respectively. The limiting grooves 162 located on the second outer segment 141 and the second inner segment 142 are set at the same height, and the limiting grooves 162 located on the first outer segment 171 and the first inner segment 172 are set at the same height. The projections of the limiting grooves 162 provided on the first outer segment 171 and the second outer segment 141 are located on the same radial line of the first hole 17 or the second hole 14. The projections of the limiting grooves 162 provided on the first inner segment 172 and the second inner segment 142 are located on the same radial line of the first hole 17 or the second hole 14. The limiting grooves 162 provided on the first outer segment 171 and the second outer segment 141 are matched in pairs. The limiting grooves 162 provided on the first inner segment 172 and the second inner segment 142 are matched in pairs.

[0071] Furthermore, in this embodiment, the limiting grooves 162 of the first outer segment 171 and the first inner segment 172 are at the same height, and the limiting grooves 162 of the second outer segment 141 and the second inner segment 142 are at the same height. In a preferred embodiment, the limiting grooves 162 of the second outer segment 141 and the second inner segment 142 are formed on the side of the second hole 14 away from the top surface of the planet carrier 11 (bottom of the second hole 14 of the planetary gear shaft 13), and the limiting grooves 162 of the first outer segment 171 and the first inner segment 172 are formed on the side of the first hole 17 near the top surface of the planet carrier 11 (top of the first hole 17 of the planet carrier 11). Secondly, the protrusion height of the limiting protrusion 161 is adapted to the depth of the limiting groove 162, ensuring that the radial force at the contact position between the limiting protrusion 161 and the limiting groove 162 is consistent with the radial force at the contact position between the sidewall of the elastic cylindrical pin 16 and the sidewalls of the first hole 17 and the second hole 14 on the same straight line.

[0072] Furthermore, the elastic cylindrical pin 16 in this embodiment is a spirally wound elastic cylindrical pin 16, that is, the elastic cylindrical pin 16 in this embodiment spirals when squeezed by external force. When the elastic cylindrical pin 16 in this embodiment is not wound, it has the same shape as the elastic cylindrical pin 16 in the basic embodiment above. The maximum diameter is greater than the diameter of the first hole 17 and the second hole 14. In a preferred embodiment, the diameter of each part of the elastic cylindrical pin 16 in this embodiment is greater than the diameter of the first hole 17 and the second hole 14.

[0073] like Figure 14 As shown, during planetary gear set operation, the elastic cylindrical pin 16 of this embodiment is subjected to the axial force of the planetary gear shaft 13, the centrifugal force of the planet carrier 11 rotation, and the tangential force between the planetary gear shaft 13 and the planet carrier 11. The combination of axial force and centrifugal force constitutes a bending moment that causes the elastic cylindrical pin 16 to bend, while the tangential force constitutes a torque that causes the elastic cylindrical pin 16 to rotate. Bending moment and torque usually coexist. The improved elastic cylindrical pin 16 and its adapting structure in this embodiment can enhance the fixing reliability of the elastic cylindrical pin 16 while increasing its service life.

[0074] Specifically, both bending moment and torque cause the elastic cylindrical pin 16 to tend to coil. After the elastic cylindrical pin 16 in the basic embodiment coils as a whole, the diameter of each part decreases. Due to the presence of bending moment and torque, it is easier for it to slip in the first hole 17 and the second hole 14, resulting in greater wear on the surface of the elastic cylindrical pin 16 body, the sidewall of the first hole 17 and the sidewall of the second hole 14. The limiting reliability weakens rapidly, the service life of the elastic cylindrical pin 16 is also shorter, and the risk of breakage at the long-term wear location increases.

[0075] In this improved embodiment, the elastic cylindrical pin 16 will generate an overall spiral winding, so as to... Figure 14Taking the limiting protrusion 161 and limiting groove 162 in the first outer section 171 and the second outer section 141 as an example; on the one hand, due to the overall spiral winding of the elastic cylindrical pin 16, the limiting protrusion 161 in the first outer section 171 tends to move to the left, and the limiting protrusion 161 in the second outer section 141 tends to move to the right. The limiting protrusion 161 in the first outer section 171 and the limiting protrusion 161 in the second outer section 141 contact and abut against the limiting groove 162. The two limiting protrusions 161 and the limiting groove 162 clamp the planet carrier 11 and the planetary gear shaft 13 with opposite forces. Compared with the simple fixed limiting in the prior art, the anti-derailment of this embodiment is more effective. The structure can reduce the tendency of planetary gear shaft 13 to expand and continue to expand. On the other hand, the limiting protrusion 161 and the limiting groove 162 clamp the planet carrier 11 and the planetary gear shaft 13 with opposite forces, making it difficult for the elastic cylindrical pin 16 to move or slip. Its position in the first hole 17 and the second hole 14 is relatively stable, and the wear caused by slippage between the first hole 17 and the second hole 14 is significantly reduced, and the service life is significantly extended. Moreover, when the planetary gear set is running relatively stably, the elastic cylindrical pin 16 is mainly subjected to centrifugal force, and the conventional cooperation of the limiting protrusion 161 and the limiting groove 162 can also play a good limiting role for the elastic cylindrical pin 16. Furthermore, the anti-detachment structure of this embodiment is more convenient to assemble and disassemble. The specific steps are as follows:

[0076] Assembly method: First, clamp the elastic cylindrical pin 16 to coil it up, making its maximum diameter less than or equal to the inner diameter of the limiting ring 18. Then, continuously pass the elastic cylindrical pin 16 through the limiting ring 18, the first hole 17, and the second hole 14. After the elastic cylindrical pin 16 partially passes through the limiting ring 18, release the elastic cylindrical pin 16 and rotate it so that the movement path of the limiting protrusion 161 does not pass through the limiting groove 162. Continuously push the elastic cylindrical pin 16 into the first hole 17 and the second hole 14. During the process... The limiting protrusion 161 contacts the sidewalls of the first hole 17 and the second hole 14, resulting in less friction and easier insertion. Due to the contact and compression between the limiting protrusion 161 and the sidewalls of the first hole 17 and the second hole 14, the elastic cylindrical pin 16 can be kept in a coiled state. Only the pushing force required into the first hole 17 and the second hole 14 is needed to pass through the limiting ring 18. After the elastic cylindrical pin 16 is inserted into place, rotating the elastic cylindrical pin 16 causes the limiting protrusion 161 to fall into the corresponding limiting groove 162, thus completing the assembly of the anti-detachment structure.

[0077] Disassembly method: First, rotate and push / pull the elastic cylindrical pin 16 outwards to disengage the limiting protrusion 161 from the limiting groove 162. The elastic cylindrical pin 16 remains in a compressed state, keeping it in a coiled state. Continue to push / pull the elastic cylindrical pin 16 outwards until it is completely outside the limiting ring 18, thus completing the disassembly of the anti-detachment structure.

[0078] The specific implementation process of the planetary gear shaft anti-disengagement structure for limiting and fixing the planetary gear shaft 13 in the above embodiment is as follows: The planetary gear shaft 13 is installed into the planetary gear shaft hole on the planet carrier 11, passing through the limiting ring 18, and the elastic cylindrical pin 16 is inserted into the first hole 17 and the second hole 14 until the elastic cylindrical pin 16 is completely located in the first hole 17 and the second hole 14, and the elastic cylindrical pin 16 provides radial force to the sidewalls of the first hole 17 and the second hole 14. If an improved embodiment is adopted, after the elastic cylindrical pin 16 is completely located in the first hole 17 and the second hole 14, the limiting protrusion 161 of the elastic cylindrical pin 16 needs to be accurately placed into the limiting groove 162 in the first hole 17 and the second hole 14, and it should be ensured that the radial force of the limiting protrusion 161 on the bottom of the limiting groove 162 is consistent with the radial force at the contact position between the sidewall of the elastic cylindrical pin 16 and the inner wall of the first hole 17 and the second hole 14.

[0079] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A planetary gear shaft anti-detachment structure, characterized in that, include: The first hole is formed in the planet carrier and penetrates the planet gear shaft mounting area. The first hole includes a first outer section. The second hole is formed on the planetary gear shaft. After the planetary gear shaft is installed in the installation area, the second hole is coaxial with the first hole. The second hole includes a second outer section. An elastic cylindrical pin, which is made of spring steel, is interference-fitted into the first hole and the second hole, and provides radial force to the sidewalls of the first hole and the second hole. A limiting ring is fixedly connected to the side of the first hole near the outer circumference of the planetary carrier. The inner diameter of the limiting ring is smaller than the diameter of the elastic cylindrical pin that is interference-fitted in the first hole and the second hole. A limiting groove is formed on the inner sidewall of the first hole and / or the inner sidewall of the second hole, and a limiting protrusion is provided on the sidewall of the elastic cylindrical pin. When the elastic cylindrical pin is interference-fitted into the first hole and the second hole, the limiting protrusion is located in the limiting groove, and the limiting protrusion and the limiting groove are clearance-fitted. Both the first outer segment and the second outer segment have limiting grooves, and the limiting grooves located in the first outer segment and the second outer segment are not at the same height; the first hole also includes a first inner segment, and the second hole also includes a second inner segment; both the first inner segment and the second inner segment have limiting grooves, and the limiting grooves located in the first inner segment and the second inner segment are not at the same height; the limiting grooves located in the second outer segment and the second inner segment are at the same height, and the limiting grooves located in the first outer segment and the first inner segment are at the same height; The projections of the limiting grooves are arranged in pairs on the same radial line of the first hole or the second hole. The elastic cylindrical pin is a spirally wound elastic cylindrical pin. When the elastic cylindrical pin is wound by external force, it is spirally wound. The maximum diameter of the elastic cylindrical pin in the unwound state is greater than the diameter of the first hole and the second hole. During operation, the elastic cylindrical pin is subjected to the axial force of the planetary gear shaft, the centrifugal force of the planetary carrier rotation, and the tangential force between the planetary gear shaft and the planetary carrier. The combination of the axial force and the centrifugal force constitutes the bending moment that causes the elastic cylindrical pin to bend, while the tangential force constitutes the torque that causes the elastic cylindrical pin to rotate. The bending moment and the torque cause the elastic cylindrical pin to have a coiling tendency. The elastic cylindrical pin coils spirally, and the limiting protrusions in the first outer section and the second outer section contact and abut against the limiting groove. The limiting protrusions in the first outer section and the second outer section generate forces in opposite directions, clamping the planetary carrier and the planetary gear shaft.

2. The planetary gear shaft anti-disengagement structure according to claim 1, characterized in that, There is a gap between the end face of the limiting ring near the elastic cylindrical pin and the end face of the elastic cylindrical pin near the limiting ring.

3. The planetary gear shaft anti-disengagement structure according to claim 1, characterized in that, The inner sidewalls of the first hole and the second hole are both provided with the limiting groove, and the sidewall of the elastic cylindrical pin is provided with limiting protrusions corresponding to the position and number of the limiting groove.

4. The planetary gear shaft anti-disengagement structure according to claim 1, characterized in that, The method for assembling the elastic cylindrical pin is as follows: clamp the elastic cylindrical pin so that the maximum diameter of the elastic cylindrical pin is less than or equal to the inner diameter of the limiting ring; pass the elastic cylindrical pin through the limiting ring, the first hole, and the second hole in sequence; release the elastic cylindrical pin; push the remaining elastic cylindrical pin outside the limiting ring completely into the first hole and the second hole; rotate and fine-tune the elastic cylindrical pin so that the limiting protrusion is located in the limiting groove. The method for disassembling the elastic cylindrical pin is as follows: rotate and push the elastic cylindrical pin outward so that the limiting protrusion disengages from the limiting groove. The elastic cylindrical pin remains in a compressed state. Continue to push the elastic cylindrical pin outward until the elastic cylindrical pin is completely outside the limiting ring.

5. A method for preventing planetary gear shaft from disengaging, based on the planetary gear shaft anti-disengagement structure according to any one of claims 1-4, characterized in that, include: The planetary gear shaft is installed onto the mounting area on the planet carrier. The elastic cylindrical pin is inserted into the first hole and the second hole through the limiting ring until the elastic cylindrical pin is completely located inside the first hole and the second hole on the inner side of the limiting ring. The elastic cylindrical pin provides radial force to the sidewalls of the first hole and the second hole.

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