Reduction gearbox
By designing a new oil return port structure with an oil baffle, oil return through hole and curved transition part in the reduction box, the problem of insufficient oil return in the existing reduction box is solved, achieving smooth discharge of lubricating oil and reducing heat generation. , improving the functionality of the reduction gearbox.
Patent Information
- Application Number
- CN202421182665.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-28
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2034-05-28
AI Technical Summary
The oil return port design of the existing gearbox has the problem of insufficient oil return, which leads to accumulation of lubricating oil in the box and the gear oil stirring to generate heat.
A new oil return port structure is designed with an oil baffle, an oil return through hole and a curved surface transition part. The oil baffle plate and the curved surface transition part are arranged on the opposite sides of the oil return through hole. The oil baffle plate starts from the bottom of the box. The wall bulges inward, and the oil return port can also be equipped with an auxiliary oil return port, and when necessary, it can be sunk in whole or in part to increase the distance from the gear device.
By improving the smooth discharge of lubricating oil, it prevents the accumulation of oil in the reduction gear box and the heat generated by gear churning oil, and improves the overall functionality of the reduction gear box.
Smart Images
Figure CN222391918U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of reduction gearboxes, in particular to a reduction gearbox with an oil return port. Background Art
[0002] The reduction box is a transmission system for mechanical equipment such as fracturing equipment. Its function is to convert the power output by the engine through the different speed ratio changes of the gears inside the reduction box, so as to achieve the effect of speed reduction and torque increase and speed increase and torque reduction, and provide different transmission capabilities for mechanical equipment such as fracturing equipment. The design of the reduction box is generally divided into a planetary-level plus parallel-level reduction box and a single parallel-level reduction box. When the existing fracturing equipment uses a single parallel-level reduction box, in order to increase the power, a double-sided single parallel-level reduction box drive is adopted. Its working principle is that the engine drives from one side and connects to the reduction box, and the reduction box on this side is then connected and driven with the reduction box on the other side through the bottom transmission shaft. The reduction box assembly composed of a parallel stage plus a planetary stage, the parallel stage and the planetary stage interface adopt a standardized flange and spline structure, so that the same planetary stage structure can quickly match and switch parallel stage reduction boxes with different speed ratios, thereby realizing the switching of different speed ratios.
[0003] The reduction gearbox is equipped with a lubrication system that can provide lubricating oil. When the reduction gearbox is running, a large amount of lubricating oil needs to circulate into each key friction contact point to form a lubricating oil film on the contact surface to avoid dry friction between the rotating transmission parts, and take away a lot of heat during the circulation process, which is beneficial to the heat dissipation of the system.
[0004] Common lubrication methods include splash (oil immersion) lubrication and forced lubrication. For splash (oil immersion) lubrication, this lubrication method is to sink the rotating gear into or partially sink the lubricating oil in the housing, and splash the oil onto other gears and bearings for lubrication. Therefore, it has a simple structure, low cost and easy maintenance. The disadvantage is that for high-speed gearboxes, this method cannot provide timely and sufficient cooling effect. If the oil level is increased to achieve the cooling effect, the excessively high oil level increases the viscous resistance of the gear to overcome the lubricating oil, and also increases the power loss caused by the pumping effect of the gear meshing on the lubricating oil.
[0005] For high-speed gearboxes, forced lubrication is often used. A certain oil pressure is established through the oil pump, and the oil is led to the friction surface. The amount of oil can be determined according to the heat that needs to be removed. This method avoids oil churning losses and can filter, cool and monitor the oil during circulation. However, the disadvantage is that it requires the design of oil channels to guide the oil, and the lubrication system is relatively complex and difficult to maintain.
[0006] The gearbox can integrate the advantages of the above two lubrication methods according to its design and positioning. When the lubrication requirements are met, splash (oil immersion) lubrication and / or forced lubrication can be selected. Forced lubrication is selected for lightweight positioning gearboxes. Lightweight positioning gearboxes have a relatively simple structure and fewer lubrication points, so forced lubrication is selected. Its oil channel design is simple,
[0007] Maintenance is convenient and the oil demand is low. The oil pump with filter can be shared with the main equipment (such as fracturing pump) without separate equipment. For medium and high speed gearboxes, splash (oil immersion) lubrication is selected for enhanced lubrication. A certain level of oil is stored at the bottom of the gearbox housing. The oil stored at the bottom is used to splash to the required place with the rotation of the gear / bearing to take away a certain amount of heat, making up for the lack of forced lubricating oil. In addition, since the splash (oil immersion) lubrication here is used as an auxiliary, the liquid level here will not be too high.
[0008] Due to the lubricating oil provided by the reduction gearbox lubrication system, an oil return port is usually set on the reduction gearbox body. The reasonable design and layout of the oil return port on the reduction gearbox body can realize the smooth circulation of the lubricating oil and prevent the accumulation of oil in the housing due to poor oil return and the heat generated by gear oil stirring.
[0009] Whether it is a parallel stage plus planetary stage two-stage reduction or a single parallel stage reduction, the lubricating oil return port is arranged at the bottom of the parallel stage housing. The prior art oil return port design has the problem that the oil return is not smooth enough. Utility Model Content
[0010] The purpose of the present application is to provide a reduction gearbox with a novel oil return port structure, which can improve the discharge of lubricating oil through the oil return port, making the oil return smooth, thereby preventing oil accumulation in the reduction gearbox body due to poor oil return and heat generated by gear oil stirring.
[0011] In order to achieve the above-mentioned purpose, according to one aspect of the utility model, the inventor has developed a reduction gearbox, which includes: a housing; and an oil return port, which is arranged on the wall at the bottom of the housing and is used to discharge the lubricating oil inside the housing, and is characterized in that the oil return port has an oil baffle plate, an oil return hole and a curved transition portion, the oil baffle plate and the curved transition portion are arranged on opposite sides of the oil return hole, and the oil baffle plate protrudes from the wall at the bottom of the housing toward the interior of the housing.
[0012] Furthermore, the reduction gearbox further comprises one or more auxiliary oil return ports, and the auxiliary oil return ports are arranged at positions on the box body different from the oil return ports.
[0013] Furthermore, the oil return port is sunken relative to the box body.
[0014] Furthermore, the oil return port and the wall at the bottom of the box body sink as a whole.
[0015] Furthermore, the oil return port is partially sunken within a range of 1 to 3 times the wall thickness of the box body with the center of the oil return through hole as the center of the circle and the diameter as the diameter.
[0016] Furthermore, the sinking height is 1 to 5 times the wall thickness of the box body.
[0017] Furthermore, when the oil return port is sunken relative to the box body, there is a transition portion between the oil return port and the shell of the box body that smoothly transitions along the throwing-out direction of the lubricating oil.
[0018] Furthermore, the reduction box further comprises a gear device arranged inside the box body, and the angle between the transition portion and the tangent direction of the tooth top circle of the gear device is 0 to 20°.
[0019] Furthermore, the reduction box further comprises a gear device arranged inside the box body, and the height of the oil baffle is set to be as high as possible without interfering with the gear device.
[0020] Furthermore, the oil return through hole is in a circular, polygonal or elliptical shape.
[0021] Furthermore, the oil baffle is integrally formed with the box body.
[0022] The technical solution adopted by the utility model can achieve the following beneficial effects:
[0023] According to the utility model, the distance between the oil return port and the tooth top circle of the gear device is increased, which is beneficial to the sedimentation and leakage of the lubricating oil, so that the lubricating oil can be discharged smoothly, and the oil accumulation in the reduction gear box due to poor oil return and the heat generated by gear oil stirring are prevented, thereby improving the overall functionality of the reduction gear box. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0025] Figure 1 is a schematic diagram showing a reduction gearbox according to an example of the utility model;
[0026] Figure 2 It shows Figure 1 An enlarged view of the oil return port;
[0027] Figure 3 is a schematic diagram showing a reduction box according to another example of the utility model, wherein an integrally sunken oil return port is shown;
[0028] Figure 4 is a schematic diagram showing a reduction box according to another example of the utility model, wherein a partially sunken oil return port is shown;
[0029] Figure 5 It shows Figure 4 An enlarged view of the partially sunken oil return port;
[0030] Figure 6 is a schematic diagram showing a reduction box according to another example of the utility model, wherein a partially sunken oil return port is shown;
[0031] Figure 7 It shows Figure 6 An enlarged view of the partially sunken oil return port;
[0032] Figure 8 1 is a schematic diagram showing a reduction box according to another example of the present utility model, wherein an oil return port seen from the inside of the reduction box is shown;
[0033] Fig. 9 It shows Figure 8 An enlarged view of the oil return port;
[0034] Fig.10 It shows Figure 8 A schematic diagram of a reduction gearbox, wherein an oil return port is shown as seen from the outside of the reduction gearbox housing;
[0035] Fig.11 It shows Fig.10 Enlarged view of the oil return port. DETAILED DESCRIPTION
[0036] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in combination with the specific embodiments of the utility model and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0037] The technical solutions disclosed in various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. For the purpose of simplicity, the reference numerals of various components are not necessarily shown in each of the accompanying drawings. Generally, for the purpose of emphasis, some drawings only show the reference numerals of the relevant components described with reference to the drawings in the specification, while omitting the relevant numerals of other components, but the same reference numerals are common for the same components in different drawings.
[0038] Figure 1 is a schematic diagram showing a reduction gearbox 1 according to an example of the present utility model, Figure 2 It shows Figure 1 An enlarged view of the oil return port. Figure 1 As shown, the reduction box 1 includes a housing 2 and a gear device 3. Figure 1 In the example of , the box body 2 includes a left arc portion A, a right arc portion B, an upper flat portion C, and a lower flat portion D as the wall of the box body 2 in the circumferential direction R. The upper flat portion C is tangentially connected to the upper side of the left arc portion A and the upper side of the right arc portion B at the same time, and the lower flat portion D is tangentially connected to the lower side of the left arc portion A and the lower side of the right arc portion B at the same time. Here, the upper flat portion C and the lower flat portion D are described relative to the left arc portion A and the right arc portion B, which means that they are connected in the following manner: Figure 1 The cross-sectional view shown is generally straight, rather than curved like the arc portion A on the left and the arc portion B on the right. It should be noted that the upper flat portion C and the lower flat portion D described here do not limit the surface of the portion to be an absolute plane, but may have a convex portion on its surface for connection, etc. The gear device 3 is arranged inside the housing 2 and generally includes, for example, a set of two gears. When the reduction box is running, the two gears mesh with each other and rotate, thereby transmitting power. Although not shown in detail, the reduction box 1 also includes a lubrication system, which provides lubricating oil required for lubrication of the operation of the reduction box 1, for example, providing lubricating oil to the rotating gear device 3 to reduce dry friction and take away heat. The amount of lubricating oil provided to the inside of the housing 2 needs to be appropriate to ensure that the reduction box operates normally and efficiently. When the amount of lubricating oil inside the reduction box 1 is too low, it may not have sufficient lubrication and heat dissipation effects, and when the amount of lubricating oil inside the reduction box 1 is too high, it may increase the viscous resistance of the gear to overcome the lubricating oil, and also increase the power loss caused by the pumping effect of the gear meshing on the lubricating oil, which may affect the operation effect of the reduction box 1. In this case, it is necessary to discharge the excess lubricating oil from the housing 2. Therefore, the reduction box 1 is also provided with an oil return port 4, through which the excess lubricating oil can be discharged from the housing 2. Figure 1 As shown, the oil return port 4 is arranged on the wall of the housing 2 of the reduction box 1. Figure 1 Two oil return ports 4 are shown in FIG. 1 , but this is only an example, and the number of the oil return ports 4 is not limited to two, and may be one or more.
[0039] In order to ensure the smooth outflow of lubricating oil, for the reduction box 1 with different installation angle requirements, the number and arrangement angle of the oil return port 4 are not limited. After the reduction box is installed, at least one oil return port 4 is provided at the low point. That is to say, in the installation state of the reduction box 1, at least one oil return port 4 is provided on the wall at the bottom of the box body 2. Auxiliary oil return ports (not shown in the figure) can be arranged at any other position of the box body 2, including but not limited to being arranged on the side surrounding surface of the box body 2 (here, the side surrounding surface refers to the side of the box body 2 that partially surrounds the gear device 3, for example, Figure 1 The bottom of the surface of the gear device 3 formed by the left and right sides of the box body 2 is partially surrounded in the view of FIG. Figure 1 The bottom of the left arc part A and the right arc part B shown in the figure. An auxiliary oil return port can also be opened at any angle on the rear end face of the box body 2 (the rear end face of the box body 2 is the end face connected to the power device) to ensure smooth oil return and meet the space for arranging the oil return pipe of the whole machine.
[0040] In addition, if Figure 1 and Figure 2 As shown, near the oil return port 4, the lubricating oil flows along the tangent direction of the gear ( Figure 2 An oil baffle plate 5 is provided on the route where the lubricating oil flies out (as shown by the arrow line in the figure), which can prevent the lubricating oil from being stirred up and flowing out from the oil return hole 6 along the oil baffle plate 5. The oil baffle plate 5 is as high as possible without interfering with the gears of the gear device 3. The higher the oil baffle plate 5 is, the more lubricating oil with excessive tangential speed can be blocked, thereby achieving a better blocking effect. Under the premise of manufacturing through a casting process and considering the uniform casting, the thickness of the oil baffle plate 5 is not limited (for example, the thickness of the oil baffle plate 5 is usually ≥5mm), and the cross-sectional shape of the oil baffle plate 5 is not limited to a regular rectangle, but can also be a trapezoidal cross-section with a reinforced root, or other cross-sections that can achieve an oil blocking effect. Here, the oil baffle plate 5 can be integrally formed with the housing 2, for example, by casting. Alternatively, the oil baffle plate 5 can also be formed into a raised structure with an oil blocking function only by local thickening and accumulation.
[0041] In order to realize the lightweight design of the reduction box 1, the parallel stage housing is designed to be extremely compact, and the inner wall is close to the rotating gear inside. In order to avoid the phenomenon of gear oil stirring due to insufficient space for the lubricating oil to fall into the bottom oil return port after flying out from the tangential direction of the gear teeth, the oil return port 4 of the utility model can have a sinking design, thereby increasing the distance between the oil return port 4 and the tooth top circle of the gear to facilitate the sedimentation and leakage of the lubricating oil. The specific sinking height of the oil return port 4 is not limited, as long as it can ensure smooth oil return and meet the space for arranging the oil return pipe of the whole machine. In addition, the sinking method of the oil return port 4 is not limited, and it can sink as a whole on the bottom surface, or sink locally around the oil return port 4.
[0042] With reference to the accompanying drawings, Figure 3is a schematic diagram showing a reduction box according to another example of the utility model, wherein an integrally sunken oil return port is shown; Figure 4 is a schematic diagram showing a reduction box according to another example of the utility model, wherein a partially sunken oil return port is shown; Figure 5 It shows Figure 4 An enlarged view of the partially sunken oil return port; Figure 6 is a schematic diagram showing a reduction box according to another example of the utility model, wherein a partially sunken oil return port is shown; Figure 7 It shows Figure 6 An enlarged view of the partially sunken oil return port. Figure 3 In FIG. 1 , an example is shown in which the two oil return ports 4 at the bottom of the reduction box 1 and the bottom wall of the housing 2 are integrally sunken relative to the housing 2. Figure 3 As shown, the two oil return ports 4 are arranged on the lower flat portion D of the housing 2, that is, on the wall at the bottom of the housing 2. Here, the wall at the bottom of the housing 2 provided with the two oil return ports 4 is sunken as a whole, specifically, its position is lower relative to the position when a tangential connection is simultaneously formed with the lower side of the left circular arc portion A and the lower side of the right circular arc portion B of the housing 2. In other words, the wall at the bottom of the housing 2 provided with the two oil return ports 4 protrudes from the lower side of the left circular arc portion A and the lower side of the right circular arc portion B of the housing 2 toward the outside of the housing 2, thereby increasing the distance between the gear device 3 and the wall at the bottom of the housing 2, especially the distance between the oil return ports 4, so as to leave a larger space for the flow of lubricating oil. Figure 4 and Figure 5 In FIG. 4 , an example of partial sinking of the oil return port 4 is shown, that is, the oil return port 4 sinks relative to the tank 2 only in the vicinity thereof. Figure 4 and Figure 5 As shown, the oil return port 4 is arranged at the bottom of one side of the housing 2, that is, arranged on the wall at the bottom of the housing 2. Here, the oil return port 4 is partially sunken relative to the housing 2 near it. Specifically, the oil return port 4 protrudes toward the outside of the housing 2 relative to the wall of the housing 2, thereby increasing the distance between the gear device 3 and the oil return port 4, so as to leave a larger space for the flow of lubricating oil. Figure 6 and Figure 7 , another example of partial sinking of the oil return port 4 is shown, in which the oil return port 4 is also arranged at the bottom of one side of the box body 2, and the oil baffle plate 5 is also shown. That is, the sinking design of the oil return port 4 can be combined with the design of the oil baffle plate 5.
[0043] The sinking height of the oil return port 4, that is, the height of the oil return port 4 protruding from the wall of the housing 2 to the outside of the housing 2, is related to factors such as the gear speed, the amount of lubricating oil, and the distance between the gear tooth top circle and the inner wall of the housing 2. Limited by the space for arranging the oil return pipe of the whole machine, the general sinking height of the oil return port 4 is 1 to 5 times the wall thickness of the housing 2. For the local sinking design of the oil return port 4, it is preferred to sink locally within the oil return port area range with the center of the oil return through hole 6 as the center of the circle and 1 to 3 times the wall thickness of the housing 2 as the diameter. There is a transition part between the sinking part and the shell of the housing 2 that smoothly transitions along the direction of the lubricating oil being thrown out, that is, the sinking part and the shell of the housing 2 need to smoothly transition along the direction of the lubricating oil being thrown out, and the angle between the transition part and the tangent direction of the tooth top circle of the gear device 3 is 0 to 20°, and it can be a plane, an inclined surface, an arc surface or any structure that can achieve stable outflow of lubricating oil.
[0044] The connection method between the box body 2 and the sunken oil return port 4 is not limited, and can be a plane connection or a curved surface connection, such as an irregular curved surface connection. The starting range, extension range and inclination angle of the curved surface are not limited, as long as the wall thickness changes evenly and the corner transitions slowly. It should be noted that the curved surface here is a curved surface that is concave downward from the surface to ensure that the lubricating oil flows out smoothly. For example, the utility model provides an implementation form of irregular curved surface connection, that is, using curved surface transition. Referring to the attached drawings, Figure 8 1 is a schematic diagram showing a reduction box according to another example of the present utility model, wherein an oil return port seen from the inside of the reduction box is shown; Fig. 9 It shows Figure 8 An enlarged view of the oil return port; Fig.10 It shows Figure 8 A schematic diagram of a reduction gearbox, wherein an oil return port is shown as seen from the outside of the reduction gearbox housing; Fig.11 It shows Fig.10 An enlarged view of the oil return port. Figure 8-Figure 11As shown, the oil return port 4 of the reduction gearbox 1 has an oil baffle plate 5, an oil return hole 6 and a curved transition portion 7. The oil baffle plate 5 and the curved transition portion 7 are arranged on opposite sides of the oil return hole 6, and the curved transition portion 7 guides the lubricating oil to the oil return hole 6, that is, the lubricating oil from the inside of the housing 2 flows into the oil return hole 6 via the curved transition portion 7, and the oil baffle plate 5 protrudes from the wall at the bottom of the housing 2 toward the inside of the housing 2 to block the lubricating oil and prevent the lubricating oil from being stirred up, that is, to prevent the lubricating oil from splashing forward due to inertia under the high-speed rotation of the gear and failing to be discharged smoothly from the oil return port 4. For example, the curved surface transition part 7 has a smooth curved surface that is concave downward from the surface of the wall of the box body 2 facing the inside of the box body and has a cup-shaped curved surface shape. The end adjacent to the oil return through hole 6 is wider than the end opposite to the end adjacent to the oil return through hole 6 and is concave deeper downward. The concave depth of the curved surface transition part 7 gradually deepens from the end connected to the wall at the bottom of the box body 2 to the end connected to the oil return through hole 6, forming a smooth curved surface, thereby forming a slow drop. In this way, the oil return port 4 adopts a cup-shaped curved surface transition to play the role of guiding and collecting oil, and guides the lubricating oil to accelerate the discharge through a slow height drop.
[0045] Although the shape of the oil return hole 6 is shown as a circle in the attached drawings, this is not restrictive. The shape of the oil return hole 6 can also be a polygon, an ellipse, or any other shape that meets the oil leakage requirements. In addition, the cross-section of the oil return port mounting boss is not limited to a regular rectangle or circle, and can also be an uneven platform or cylinder with non-uniform cross-section, or the rigidity of the oil return hole can be ensured only by irregular accumulation and thickening of local materials. The position of the bolt holes for connecting the oil return pipe is not limited to the rectangular four-corner arrangement shown in the figure, and the number and arrangement orientation of the threaded holes are not limited. They can be arranged along the edge of the oil return port mounting boss, or along the circumference, or staggered, etc., as long as the connection and fixation of the oil return port pipe can be achieved. The oil return hole can be directly formed by casting or machined.
[0046] The beneficial effects of the utility model are:
[0047] According to the utility model, the distance between the oil return port and the tooth top circle is increased, which is beneficial to the sedimentation and leakage of the lubricating oil. The cup-shaped curved surface transition can guide the lubricating oil to accelerate the leakage through a slow height drop under the action of gravity, so that the lubricating oil can be discharged smoothly, thereby improving the overall functionality of the reduction box.
[0048] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.
[0049] List of reference numerals:
[0050] 1 Gearbox
[0051] 2 Cabinet
[0052] 3 Gear unit
[0053] 4 Oil return port
[0054] 5 Oil baffle
[0055] 6 Oil return hole
[0056] 7 Surface transition
[0057] R Circumferential direction
[0058] A Left arc part
[0059] B Right arc part
[0060] C Upper flat part
[0061] D Lower flat part
Claims
1. A reduction gearbox, comprising: Box (2); and An oil return port (4), the oil return port (4) being arranged on the wall at the bottom of the box body (2) and used for discharging lubricating oil inside the box body (2), characterized in that: The oil return port (4) comprises an oil baffle plate (5), an oil return through hole (6) and a curved transition portion (7); the oil baffle plate (5) and the curved transition portion (7) are arranged on opposite sides of the oil return through hole (6), and the oil baffle plate (5) protrudes from the wall at the bottom of the box body (2) toward the inside of the box body (2).
2. The reduction gearbox according to claim 1, characterized in that: The reduction gearbox further comprises one or more auxiliary oil return ports, wherein the auxiliary oil return ports are arranged at positions on the housing (2) different from the oil return port (4).
3. The reduction gearbox according to claim 1, characterized in that: The oil return port (4) is sunken relative to the casing (2).
4. The reduction gearbox according to claim 3, characterized in that: The oil return port (4) sinks integrally with the wall at the bottom of the box body (2).
5. The reduction gearbox according to claim 3, characterized in that: The oil return port (4) is partially sunken within a range of 1 to 3 times the wall thickness of the box body (2) with the center of the oil return through hole (6) as the center and the diameter as the outside.
6. The reduction gearbox according to any one of claims 3 to 5, characterized in that: The sinking height is 1 to 5 times the wall thickness of the box body (2).
7. The reduction gearbox according to claim 3, characterized in that: When the oil return port (4) sinks relative to the box body (2), a transition portion is provided between the oil return port (4) and the shell of the box body (2) for smooth transition along the direction in which the lubricating oil is thrown out.
8. The reduction gearbox according to claim 7, characterized in that: The reduction box further comprises a gear device (3) arranged inside the box body (2), and the angle between the transition portion and the tangent direction of the tooth top circle of the gear device (3) is 0 to 20 degrees.
9. The reduction gearbox according to claim 1, characterized in that: The reduction box further comprises a gear device (3) arranged inside the box body (2), and the height of the oil baffle plate (5) is set to be as high as possible without interfering with the gear device (3).
10. The reduction gearbox according to claim 1, characterized in that: The shape of the oil return through hole (6) is circular, polygonal or elliptical.
11. The reduction gearbox according to claim 1, characterized in that: The oil baffle plate (5) is integrally formed with the box body (2).