A three-stage gear box

Abstract

A kind of three-stage gear box, including inner shell, the inner side of the inner shell is provided with ring gear, the inner side of the inner shell is provided with gear carrier, three groups of planetary gear sets are provided on the gear carrier along axis, the planetary gear sets are linked with driving shaft extending out of inner shell, cooling structure is provided on the inner shell, the cooling structure includes axial groove being provided along axis direction, the axial groove is communicated with annular groove being provided along circumference direction, the axial groove is used to guide cooling liquid into annular groove, in turn, flow to the surface of inner shell.By the technical scheme, cooling liquid can be guided into axial groove from annular groove, and is evenly distributed along the circumference of inner shell, overcome the defect that oil liquid in traditional three-stage gear box is slow in part of tooth surface or bearing area, forms "dead zone", realize that cooling liquid is covered to tooth surface and bearing overall, effectively avoid local overheating and fatigue failure.

Description

Technical Field

[0001] This utility model relates to a three-stage gearbox, belonging to the field of gearboxes. Background Technology

[0002] With the development of engineering machinery, rail transportation, and new energy equipment, gearboxes are evolving towards higher speeds, higher torques, higher power densities, and miniaturization. Three-stage gearboxes, due to their ability to achieve large reduction ratios and output stable torque within limited space, are widely used in wind power, vehicle drives, industrial automation, and other applications.

[0003] In existing technologies, common three-stage gearboxes typically employ a combination of spur or helical gears, transmitting power stage by stage through the input shaft, two intermediate shafts, and the output shaft. Oil baths or splash lubrication are installed within the gearbox to remove frictional heat and reduce tooth surface wear. However, this type of structure still suffers from several prominent problems. Due to the limited size of the gearbox, the internal lubrication channels are often simply arranged, resulting in slow oil flow or even "dead zones" at certain tooth surfaces and bearings, causing localized overheating and wear. Maintenance is difficult: most existing three-stage gearboxes are integral housings. If a gear, bearing, or cooling oil circuit in a particular stage is damaged, the entire unit must be disassembled for repair, leading to long maintenance cycles and low efficiency. Similar to the uneven cooling caused by an excessively large oil circuit cross-section in motor cooling structures, existing three-stage gearboxes also suffer from uneven lubrication and load distribution. Some tooth surfaces and bearing areas experience insufficient load or oil flow, while other areas have low utilization rates. This uneven distribution directly leads to reduced heat dissipation capacity, increased tooth surface fatigue, and shortened service life. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a three-stage gearbox.

[0005] A three-stage gearbox includes an inner shell, an annular gear on the inner side of the inner shell, a gear carrier on the inner side of the inner shell, three sets of planetary gears on the gear carrier along an axis, the planetary gear sets being driven by a drive shaft extending out of the inner shell, and a cooling structure on the inner shell, the cooling structure including an axial groove arranged along the axial direction, the axial groove communicating with an annular groove arranged circumferentially, the axial groove being used to guide coolant into the annular groove, and then to the surface of the inner shell.

[0006] This technical solution allows the coolant to be introduced from the annular groove into the axial groove and evenly distributed along the circumference of the inner shell. This overcomes the shortcomings of traditional three-stage gearboxes where the oil flow is slow and forms "dead zones" on certain tooth surfaces or bearing areas. It achieves comprehensive coolant coverage of the tooth surfaces and bearings, effectively preventing localized overheating and fatigue failure. Because the coolant circulates between the annular and axial grooves, a large, uniform cooling zone is formed on the inner shell surface, improving the overall heat dissipation efficiency of the gearbox. Compared to traditional structures relying on oil baths or splash lubrication, this solution can quickly remove frictional heat, reduce gearbox temperature rise, and extend the service life of gears and bearings.

[0007] Furthermore, the annular groove consists of multiple U-shaped grooves arranged circumferentially along the inner shell. The U-shaped grooves are nested and connected end to end from the inside to the outside. Each U-shaped groove has two local grooves arranged circumferentially.

[0008] This technical solution utilizes an annular groove composed of multiple nested U-shaped grooves connected end-to-end from the inside out. This creates multiple flow paths for the coolant around the inner shell, significantly increasing the heat exchange area between the coolant and the inner shell compared to a single annular groove, thereby improving heat dissipation efficiency. The coolant can pass sequentially through each U-shaped groove, avoiding the phenomenon of excessively high or low flow rates in some areas of a single annular groove. This results in a more uniform distribution of coolant on the inner shell surface, enhancing the consistency of lubrication and cooling.

[0009] Preferably, the U-shaped grooves are connected by partial grooves, and the starting end of the annular groove is located on the innermost U-shaped groove.

[0010] This technical solution allows the coolant to flow layer by layer from the inside out, as the starting end of the annular groove is located at the innermost U-shaped groove. This ensures that heat inside the gearbox is carried away first and then transferred outwards, resulting in a more rational cooling sequence and avoiding the phenomenon of the outer layer cooling first while the inner layer lags behind. The multi-layered nested U-shaped groove design allows for flexible design of the number of cooling circuit layers according to the power and speed requirements of different gearboxes, offering good scalability and applicability, and accommodating the heat dissipation needs of both miniaturized and high-power gearboxes.

[0011] Preferably, the outermost U-shaped groove is connected to the center of the axial groove by a transition groove.

[0012] This technical solution allows the coolant to smoothly return to the axial groove after completing multi-stage circulation from the inside out, preventing flow interruption or liquid accumulation and ensuring a closed and stable cooling circuit. Without the transition groove, the coolant might stagnate at the outermost U-shaped groove, preventing heat from being dissipated from the outer shell area in a timely manner. The addition of the transition groove allows the coolant in the outer U-shaped groove to flow back quickly, preventing stagnation and localized overheating.

[0013] Furthermore, the annular grooves are symmetrically arranged on the inner shell wall, the axial groove is connected to the annular grooves on both sides, and the length of the annular grooves is set along the circumference of the inner shell.

[0014] With this technical solution, the annular grooves are symmetrically arranged on the inner shell wall, which can ensure that both sides of the inner shell receive coolant flow at the same time, avoiding the uneven temperature difference between one side being too cold and the other side being too hot, thereby improving the overall thermal balance inside the gearbox.

[0015] Preferably, the local groove and the axial groove are arranged in a rectangular groove.

[0016] This technical solution simplifies the structure of rectangular grooves during machining on the inner wall of the housing, makes machining accuracy easy to control, reduces manufacturing costs, and improves the reliability of communication between grooves.

[0017] Furthermore, the inner shell is covered by an outer shell that seals the axial groove and the annular groove. The outer shell is provided with an injection port for adding coolant to the innermost U-shaped groove, and the injection port is sealed by a sealing plug.

[0018] This technical solution utilizes an outer shell surrounding an inner shell to completely cover the axial and annular grooves, forming a closed cooling chamber. This prevents coolant leakage or evaporation loss during operation, ensuring long-term stable operation of the cooling system. A filler port on the outer shell allows for convenient direct addition of coolant to the innermost U-shaped groove, enabling rapid replenishment and replacement, significantly reducing maintenance difficulty and downtime.

[0019] Preferably, the coolant includes ethylene glycol-based coolant or propylene glycol-based coolant.

[0020] This technical solution enables ethylene glycol-based or propylene glycol-based coolants to exhibit excellent antifreeze properties, ensuring that the three-stage gearbox maintains coolant fluidity even in low-temperature environments, making it suitable for outdoor equipment such as wind power and rail transportation. Ethylene glycol-based and propylene glycol-based coolants typically contain corrosion inhibitors, effectively preventing corrosion of the inner casing and cooling tank due to prolonged contact with the liquid, while also reducing the risk of impurity deposition and channel blockage, ensuring long-term unobstructed cooling channels.

[0021] The beneficial effects of this invention are as follows: The coolant can be introduced into the axial groove from the annular groove and evenly distributed along the circumference of the inner shell, overcoming the defects of slow oil flow and "dead zones" in some tooth surfaces or bearing areas in traditional three-stage gearboxes. This achieves comprehensive coolant coverage of the tooth surfaces and bearings, effectively preventing localized overheating and fatigue failure. Because the coolant can circulate between the annular and axial grooves, a large, uniform cooling zone is formed on the surface of the inner shell, improving the overall heat dissipation efficiency of the gearbox. Compared with traditional structures relying on oil baths or splash lubrication, this solution can quickly remove frictional heat, reduce gearbox temperature rise, and extend the service life of gears and bearings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of this utility model with the inner shell and outer shell removed; Figure 3 This is a schematic diagram of the structure of this utility model with the outer shell removed; Figure 4 This is a planar unfolded schematic diagram of the cooling structure; In the diagram, 1 is the inner shell; 11 is the gear carrier; 12 is the planetary gear set; 13 is the drive shaft; 2 is the cooling structure; 21 is the axial groove; 22 is the annular groove; 221 is the U-shaped groove; 222 is the local groove; 223 is the transition groove; 3 is the outer shell; 31 is the liquid injection port. Detailed Implementation

[0024] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0025] It should be noted that all uses of "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this utility model. Subsequent embodiments will not explain this in detail.

[0026] The directional and positional terms used in this utility model, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0027] like Figure 1-4As shown, this is an embodiment of a three-stage gearbox of the present invention, including an inner shell 1. An annular gear is provided on the inner side of the inner shell 1. A gear carrier 11 is provided on the inner side of the inner shell 1. Three sets of planetary gear sets 12 are provided along the axis on the gear carrier 11. The planetary gear sets 12 are linked to a drive shaft 13 extending out of the inner shell 1. A cooling structure 2 is provided on the inner shell 1. The cooling structure 2 includes an axial groove 21 arranged along the axial direction. The axial groove 21 is connected to an annular groove 22 arranged circumferentially. The axial groove 21 is used to guide the coolant into the annular groove 22 and then flow to the surface of the inner shell 1.

[0028] This technical solution allows the coolant to be introduced from the annular groove 22 into the axial groove 21 and evenly distributed circumferentially along the inner shell 1. This overcomes the shortcomings of traditional three-stage gearboxes where the oil flow is slow and forms "dead zones" on certain tooth surfaces or bearing areas, achieving comprehensive coolant coverage of the tooth surfaces and bearings, effectively preventing localized overheating and fatigue failure. Because the coolant can circulate between the annular groove 22 and the axial groove 21, a large, uniform cooling zone is formed on the surface of the inner shell 1, improving the overall heat dissipation efficiency of the gearbox. Compared to traditional structures relying on oil baths or splash lubrication, this solution can quickly remove frictional heat, reduce gearbox temperature rise, and extend the service life of gears and bearings.

[0029] The annular groove 22 consists of a plurality of U-shaped grooves 221 arranged circumferentially along the inner shell 1. The U-shaped grooves 221 are nested and connected end to end from the inside to the outside. Each U-shaped groove 221 has two local grooves 222 arranged circumferentially.

[0030] This technical solution utilizes an annular groove 22, which consists of multiple nested U-shaped grooves 221 connected end-to-end from the inside out. This creates a multi-loop flow path for the coolant around the inner shell 1, significantly increasing the heat exchange area between the coolant and the inner shell 1 compared to a single annular groove 22, thereby improving heat dissipation efficiency. The coolant can pass sequentially through each U-shaped groove 221, avoiding the phenomenon of excessively high or slow flow rates in some areas of a single annular groove. This results in a more uniform distribution of coolant on the surface of the inner shell 1, enhancing the consistency of lubrication and cooling.

[0031] The U-shaped groove 221 is connected by a local groove 222, and the starting end of the annular groove 22 is located on the innermost U-shaped groove 221.

[0032] With this technical solution, since the starting end of the annular groove 22 is located at the innermost U-shaped groove 221, the coolant can flow layer by layer from the inside out, allowing the heat inside the gearbox to be carried away first and then transferred to the outside. This results in a more rational cooling sequence, avoiding the phenomenon of the outer layer cooling first while the inner layer lags behind. The use of multi-layer nested U-shaped grooves 221 allows for flexible design of the number of cooling circuit layers according to the power and speed requirements of different gearboxes, offering good scalability and applicability, and accommodating the heat dissipation needs of both miniaturized and high-power gearboxes.

[0033] The outermost U-shaped groove 221 is connected to the center of the axial groove 21 by a transition groove 223.

[0034] This technical solution ensures that the coolant, after completing multi-stage circulation from the inside out, can smoothly flow back to the axial groove 21, preventing flow interruption or liquid accumulation and ensuring a closed and stable cooling circuit. Without the transition groove 223, the coolant might stagnate at the outermost U-shaped groove 221, preventing heat from being dissipated from the outer shell 3 area in a timely manner. The addition of the transition groove 223 allows the coolant in the outer U-shaped groove 221 to flow back quickly, preventing stagnation and localized overheating.

[0035] The annular grooves 22 are symmetrically arranged on the inner shell 1 wall, the axial grooves 21 are connected to the annular grooves 22 on both sides, and the length of the annular grooves 22 is arranged along the circumference of the inner shell 1.

[0036] With this technical solution, the annular groove 22 is symmetrically arranged on the wall of the inner shell 1, which can ensure that the coolant flows on both sides of the inner shell 1 at the same time, avoiding the uneven temperature difference between one side being too cold and the other side being too hot, thereby improving the overall thermal balance inside the gearbox.

[0037] The local groove 222 and the axial groove 21 are arranged in a rectangular groove.

[0038] This technical solution simplifies the structure of rectangular grooves during machining on the inner wall of the housing, makes machining accuracy easy to control, reduces manufacturing costs, and improves the reliability of communication between grooves.

[0039] The inner shell 1 is covered by an outer shell 3 that forms a seal between the axial groove 21 and the annular groove 22. The outer shell 3 is provided with a liquid injection port 31 for adding coolant to the innermost U-shaped groove 221. The liquid injection port 31 is sealed by a sealing plug.

[0040] This technical solution involves enclosing the inner shell 1 with the outer shell 3, completely covering the axial groove 21 and the annular groove 22 to form a closed cooling chamber. This prevents coolant leakage or evaporation loss during operation, ensuring long-term stable operation of the cooling system. The outer shell 3 has a filling port 31, allowing for convenient direct addition of coolant to the innermost U-shaped groove 221, enabling rapid replenishment and replacement, significantly reducing maintenance difficulty and downtime.

[0041] The coolant includes ethylene glycol-based coolant or propylene glycol-based coolant.

[0042] This technical solution enables ethylene glycol-based or propylene glycol-based coolants to exhibit excellent antifreeze properties, ensuring the three-stage gearbox maintains coolant fluidity even in low-temperature environments, making it suitable for outdoor equipment such as wind power and rail transportation. Ethylene glycol-based and propylene glycol-based coolants typically contain corrosion inhibitors, effectively preventing corrosion of the inner shell and cooling tank due to prolonged contact with the liquid, while also reducing the risk of impurity deposition and channel blockage, ensuring long-term unobstructed cooling channels.

[0043] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

[0044] Although the present invention has been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A three-stage gearbox, characterized in that: The device includes an inner shell, an inner ring gear, a gear carrier, and three sets of planetary gears along an axis on the gear carrier. The planetary gears are linked to a drive shaft extending out of the inner shell. The inner shell has a cooling structure, which includes an axial groove arranged along the axial direction and connected to an annular groove arranged circumferentially. The axial groove is used to guide coolant into the annular groove and then to the surface of the inner shell.

2. The three-stage gearbox as described in claim 1, characterized in that: The annular groove consists of multiple U-shaped grooves arranged circumferentially along the inner shell. The U-shaped grooves are nested and connected end to end from the inside to the outside. Each U-shaped groove has two local grooves arranged circumferentially.

3. The three-stage gearbox as described in claim 2, characterized in that: The U-shaped grooves are connected by local grooves, and the starting end of the annular groove is located on the innermost U-shaped groove.

4. The three-stage gearbox as described in claim 2, characterized in that: The outermost U-shaped groove is connected to the center of the axial groove by a transition groove.

5. The three-stage gearbox as described in claim 1, characterized in that: The annular grooves are symmetrically arranged on the inner shell wall, the axial groove is connected to the annular grooves on both sides, and the length of the annular grooves is set along the circumference of the inner shell.

6. The three-stage gearbox as described in claim 5, characterized in that: The local groove and the axial groove are arranged in a rectangular groove.

7. The three-stage gearbox as described in claim 1, characterized in that: The inner shell is covered by an outer shell that seals the axial groove and the annular groove. The outer shell is provided with a liquid injection port for adding coolant to the innermost U-shaped groove. The liquid injection port is sealed by a sealing plug.

8. The three-stage gearbox as described in claim 7, characterized in that: The coolant includes ethylene glycol-based coolant or propylene glycol-based coolant.

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