Self-lubricating structure of planetary gear train

Abstract

The invention discloses a planetary gear train self-lubricating structure, and belongs to the technical field of speed reducer lubrication of electric aircrafts. The structure comprises an output shaft, a first bearing, a second bearing, a shell, a lubricating impeller, a planet carrier, a sun wheel shaft, a sun wheel, a planet wheel, a planet wheel bearing, an inner gear ring, an input shaft and a lubricating oil way structure. Compared with the prior art, the lubricating device has the following beneficial effects that lubricating oil can be conveyed to the bearing from an oil pool of the gear box only through rotation of the sun gear, the planet gear and the like without additionally adding an oil pump, and the purposes of lubricating oil circulation and bearing lubrication are achieved; the lubricating requirements of the speed reducer in different positions and postures can be met, and the overall structure is compact; the power-to-weight ratio (power / weight) of the structure is large, the transmission ratio is large, the structure is compact, and the weight is light under the condition that the requirements of using working conditions are met.

Description

Technical Field

[0001] The invention belongs to the technical field of reducer lubrication of electric aircraft, and in particular relates to a self-lubricating structure of a planetary gear train. Background Art

[0002] The reducer plays a vital role in electric aircraft. It is mainly used to convert the high-speed rotational power generated by the engine into low-speed, high-torque power suitable for the aircraft's propellers or rotors, so as to achieve the aircraft's take-off, flight, and landing. In multi-rotor electric aircraft, the main reducer, as a central force-bearing component, not only transmits engine power, but also bears all the forces and torques generated by the rotors. Therefore, the performance requirements for the main reducer are extremely high, including high power transmission, light weight, high transmission efficiency, and good reliability. The compact design structure and good lubrication characteristics are of great significance to the lightweight and stable operation of the reducer.

[0003] In the reducer of a multi-rotor electric aircraft, the reducer will change to different positions and attitudes as the overall flight attitude changes during flight, such as common vertical takeoff, tilt and reverse tilt, etc. The flight conditions are relatively harsh, which puts extremely high demands on the lubrication of the reducer bearings. The traditional solution is to use multiple external lubricating oil pumps to transport the lubricating oil from the bottom of the reducer to the bearings or gears that need lubrication to achieve the circulation of the lubricating oil inside the reducer; this method greatly increases the overall weight of the reducer and puts extremely high demands on the oil level line of the reducer (to prevent the lubricating oil pump from pumping air and damaging the lubricating oil pump). The reducer is relatively complex and not easy to design and maintain as a whole. Summary of the invention

[0004] The purpose of an embodiment of the present invention is to provide a planetary gear train self-lubricating structure, which can realize the circulation of lubricating oil inside the reducer by setting a lubricating oil circuit structure and a lubricating impeller, thereby solving at least one technical problem involved in the background technology.

[0005] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0006] The embodiment of the present invention provides a self-lubricating structure of a planetary gear system, comprising an output shaft, a first bearing, a second bearing, a housing, a lubricating impeller, a planet carrier, a sun gear shaft, a sun gear, a planet gear, a planet gear bearing, an inner gear ring, an input shaft and a lubricating oil path structure, wherein the output shaft is rotatably arranged in the housing through the first bearing and the second bearing; the lubricating impeller is rotatably arranged on the output shaft and is located between the first bearing and the second bearing; the planet carrier is fixed on the output shaft; the sun gear shaft is arranged below the output shaft; the sun gear is fixed on the sun gear shaft; the planet gear is rotatably arranged through the planet gear bearing is arranged on the planetary carrier and the planetary gear is meshed with the sun gear; the inner gear ring is fixed on the housing and meshed with the planetary gear; the input shaft is arranged below the sun gear shaft and is fixedly connected to the sun gear shaft; the lubricating oil circuit structure includes an oil circuit input end arranged near the inner gear ring to introduce lubricating oil for lubricating the planetary gear, an oil collecting ring arranged between the first bearing and the second bearing for storing lubricating oil, and an oil inlet pipe connecting the oil circuit input end and the oil collecting ring, and the lubricating impeller is located in the oil collecting ring to bring the lubricating oil in the oil collecting ring into the first bearing and the second bearing by stirring.

[0007] Optionally, the oil collecting ring is also provided with a plurality of vent caps.

[0008] Optionally, the output shaft and the planet carrier are fixedly connected via a spline.

[0009] Optionally, the sun gear and the sun gear shaft are fixedly connected via a spline.

[0010] Optionally, the sun gear shaft and the input shaft are fixedly connected via a spline.

[0011] Optionally, the housing includes an upper housing and a lower housing fixed to a bottom end cover of the upper housing, a first seal is provided between the output shaft and the upper housing, and a second seal is provided between the input shaft and the lower housing.

[0012] Optionally, the input shaft is connected to the external motor via an input flange.

[0013] Optionally, the output shaft is hollow inside and has a sealing end cover at its bottom end.

[0014] Optionally, the sealing end cover is fixed to the bottom end of the output shaft by a locking nut.

[0015] Optionally, an output casing for storing lubricating oil is also provided above the inner gear ring, and the oil circuit input end is connected to the output casing.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention realizes that there is no need to add an additional oil pump. The lubricating oil can be transported from the oil pool of the gear box to the bearing only by utilizing the rotation of the sun gear, planetary gear, etc., so as to achieve the purpose of lubricating oil circulation and bearing lubrication, and can meet the lubrication requirements of the reducer in different positions and postures, and the overall structure is relatively compact.

[0018] 2. The structure of the present invention has a large power-to-weight ratio (power / weight) and a relatively large transmission ratio. While meeting the requirements of the operating conditions, the structure is compact and the weight is light. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0020] Figure 1 A schematic diagram of the overall structure of the planetary gear train self-lubricating structure provided by the present invention;

[0021] Figure 2 A schematic diagram of the structure of the lubricating oil circuit provided by the present invention;

[0022] Figure 3 A schematic diagram of the structure of the upper shell provided by the present invention;

[0023] Figure 4 A schematic diagram of the assembly structure of the lubricating impeller provided by the present invention;

[0024] Figure 5 This is a schematic diagram of the three-dimensional structure of the lubricating impeller provided by the present invention. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figures 1 to 5 As shown, an embodiment of the present invention provides a planetary gear self-lubricating structure, including an output shaft 1, a first bearing 2, a second bearing 3, a housing 4, a lubricating impeller 5, a planet carrier 6, a sun gear shaft 7, a sun gear 8, a planetary gear 9, a planetary gear bearing 10, an inner gear ring 11, an input shaft 12 and a lubricating oil circuit structure.

[0027] The output shaft 1 is hollow inside, and a sealing end cover 13 is provided at the bottom end thereof. Specifically, the sealing end cover 13 is fixed to the bottom end of the output shaft 1 by a locking nut 14 .

[0028] Furthermore, the output shaft 1 is rotatably disposed in the housing 4 via the first bearing 2 and the second bearing 3 .

[0029] The first bearing 2 and the second bearing 3 are arranged vertically and spaced apart from each other.

[0030] The lubricating impeller 5 is rotatably disposed on the output shaft 1 and is located between the first bearing 2 and the second bearing 3 .

[0031] The planet carrier 6 is fixed to the output shaft 1 via splines.

[0032] The sun gear shaft 7 is disposed below the output shaft 1 , and the sun gear 8 is fixed on the sun gear shaft 7 via splines.

[0033] The planetary gear 9 is rotatably disposed on the planetary carrier 6 via a planetary gear bearing 10 and the planetary gear 9 is meshed with the sun gear 8 .

[0034] The inner gear ring 11 is fixed on the housing 4 and meshes with the planetary gears 9 .

[0035] The input shaft 12 is disposed below the sun gear shaft 7 and is fixedly connected to the sun gear shaft 7 via a spline.

[0036] The lubricating oil circuit structure includes an oil circuit input end 15 arranged near the inner gear ring 11 to introduce lubricating oil for lubricating the planetary gear 9, an oil collecting ring 16 arranged between the first bearing 2 and the second bearing 3 for storing lubricating oil, and an oil inlet pipe 17 connecting the oil circuit input end 15 and the oil collecting ring 16. The lubricating impeller 5 is located in the oil collecting ring 16 to bring the lubricating oil in the oil collecting ring 16 into the first bearing 2 and the second bearing 3 through stirring.

[0037] Furthermore, the oil collecting ring 16 is also provided with a plurality of vent caps 161 .

[0038] The housing 4 includes an upper housing 41 and a lower housing 42 fixed to the bottom end cover of the upper housing 41 . A first seal 18 is provided between the output shaft 1 and the upper housing 41 ; a second seal 19 is provided between the input shaft 12 and the lower housing 42 .

[0039] The input shaft 12 is connected to the external motor via an input flange 20 .

[0040] An output casing 21 for storing lubricating oil is also disposed above the inner gear ring 11 , and the oil circuit input end 15 is connected to the output casing 21 .

[0041] The working principle of the planetary gear train self-lubricating structure provided by the embodiment of the present invention is as follows:

[0042] 1) When the planet carrier 6 is arranged vertically, a certain volume of lubricating oil is added to the inside of the housing 4. When the reducer is running, the lubricating oil is quickly led to the planetary gear bearing 10 as the planetary gear 9 rotates, and the lubrication of the planetary gear 9, the sun gear 8, the inner gear ring 11, and the planetary gear bearing 10 is met. With the continuous rotation of the planetary gear 9, the lubricating oil is continuously accelerated under the action of the kinetic energy of the gear, and rotates and flows along the inner wall of the housing 4 of the reducer. At this time, the kinetic energy of the lubricating oil is gradually converted into potential energy, and the lubricating oil is led to the upper part of the second bearing 3 along the oil guide pipe 17 on the housing 4. In the oil collecting ring 16, and under the action of gravity, the lubricating oil flows into the second bearing 3, and then flows out from the bottom of the second bearing 3. The lubricating oil collected in the oil collecting ring 16 is brought into the first bearing 2 under the stirring of the lubricating impeller 5; and two ventilation caps 161 are opened inside the oil collecting ring 16. The ventilation cap 161 balances the pressure in the oil collecting ring area to the external atmospheric pressure, forming a pressure difference with the planetary gear area, which helps the lubricating oil to enter the oil collecting ring 16 from the bottom of the low-pressure area along the oil guide pipe 17, completing the oil lubrication process of the entire reducer, and the bearings and gears of the entire system meet the lubrication requirements.

[0043] 2) When the planet carrier 6 is arranged horizontally, a certain volume of lubricating oil is added to the inside of the housing 4. The lubrication method of the planetary gear bearing 10, the sun gear 8, the planetary gear 9, the inner ring gear 11, etc. is consistent with that when arranged vertically, and the lubrication method of the second bearing 3 and the first bearing 2 is as follows: the lubricating oil continuously accelerates the rotation under the action of the gear kinetic energy, and rotates and flows along the inner wall of the reducer housing. At this time, the kinetic energy of the lubricating oil is gradually converted into potential energy. The lubricating oil is led along the oil circuit input end 15 on the housing to the oil collecting ring 16 above the second bearing 3, and the circulation of the lubricating oil is driven by rotation to meet the lubrication requirements.

[0044] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0045] In addition, it should be noted that the scope of the methods and systems in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0046] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A planetary gear train self-lubricating structure, characterized in that: The invention comprises an output shaft, a first bearing, a second bearing, a housing, a lubricating impeller, a planet carrier, a sun gear shaft, a sun gear, a planet gear, a planet gear bearing, an inner gear ring, an input shaft and a lubricating oil path structure, wherein the output shaft is rotatably arranged in the housing through the first bearing and the second bearing; the lubricating impeller is rotatably arranged on the output shaft and is located between the first bearing and the second bearing; the planet carrier is fixed on the output shaft; the sun gear shaft is arranged below the output shaft; the sun gear is fixed on the sun gear shaft; the planet gear is rotatably arranged on the planet carrier through the planet gear bearing The planetary gear is meshed with the sun gear; the inner gear ring is fixed on the housing and meshed with the planetary gear; the input shaft is arranged below the sun gear shaft and is fixedly connected to the sun gear shaft; the lubricating oil circuit structure includes an oil circuit input end arranged near the inner gear ring to introduce lubricating oil used to lubricate the planetary gear, an oil collecting ring arranged between the first bearing and the second bearing for storing lubricating oil, and an oil inlet pipe connecting the oil circuit input end and the oil collecting ring, and the lubricating impeller is located in the oil collecting ring to bring the lubricating oil in the oil collecting ring into the first bearing and the second bearing through stirring.

2. The self-lubricating structure of the planetary gear train according to claim 1, characterized in that: The oil collecting ring is also provided with a plurality of vent caps.

3. The self-lubricating structure of the planetary gear train according to claim 1, characterized in that: The output shaft and the planet carrier are fixedly connected via splines.

4. The self-lubricating structure of the planetary gear train according to claim 1, characterized in that: The sun gear and the sun gear shaft are fixedly connected via a spline.

5. The self-lubricating structure of the planetary gear train according to claim 1, characterized in that: The sun gear shaft and the input shaft are fixedly connected via a spline.

6. The self-lubricating structure of the planetary gear train according to claim 1, characterized in that: The housing comprises an upper housing and a lower housing fixed to the bottom end cover of the upper housing. A first sealing member is arranged between the output shaft and the upper housing; and a second sealing member is arranged between the input shaft and the lower housing.

7. The self-lubricating structure of a planetary gear train according to claim 1, characterized in that: The input shaft is connected to the external motor via an input flange.

8. The self-lubricating structure of a planetary gear train according to claim 1, characterized in that: The output shaft is hollow inside and has a sealing end cover at its bottom end.

9. The self-lubricating structure of the planetary gear train according to claim 8, characterized in that: The sealing end cover is fixed to the bottom end of the output shaft through a locking nut.

10. The self-lubricating structure of a planetary gear train according to claim 1, characterized in that: An output casing for storing lubricating oil is also provided above the inner gear ring, and the oil circuit input end is connected to the output casing.

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