CN110925364A

CN110925364A - Planetary reducer for coaxial counter-rotating helicopter

Info

Publication number: CN110925364A
Application number: CN201911130141.4A
Authority: CN
Inventors: 吴冲; 许新宇; 鲁公平
Original assignee: Yifei Hainan Technology Co Ltd
Current assignee: Yifei Hainan Technology Co Ltd
Priority date: 2019-11-18
Filing date: 2019-11-18
Publication date: 2020-03-27

Abstract

The invention discloses a planetary reducer for a coaxial contra-rotating helicopter, which comprises an intermediate transmission shaft, a primary sun gear, a plurality of primary planet gears, a primary inner gear ring, a connecting frame, a plurality of secondary planet gears, a secondary sun gear and a secondary planet gear, wherein the primary sun gear is fixed at the top of the intermediate transmission shaft, the plurality of primary planet gears are meshed with the primary sun gear, the primary inner gear ring is meshed with the primary planet gears, the connecting frame is used for fixedly connecting the primary inner gear ring with an outer shaft, the plurality of secondary planet gears are coaxially arranged with the primary planet gears, the secondary sun gear is coaxially arranged above the primary sun gear in a relatively rotating mode and is meshed with the secondary planet gears for transmission, the secondary sun gear is in transmission connection with the inner shaft, the primary planet gears and the secondary planet gears are coaxially arranged in a. The speed reducer of the invention is provided with a group of primary planetary gear trains, which comprise a sun gear, a plurality of planetary gears and an inner gear ring; a group of secondary planetary gear trains comprises a sun gear and a plurality of planetary gears, and is not provided with an inner gear ring. The reducer has a fixed planet carrier, and is shared by a primary planetary gear train and a secondary planetary gear train.

Description

Planetary reducer for coaxial counter-rotating helicopter

Technical Field

The invention belongs to the technical field of mechanical transmission devices, and particularly relates to a planetary reducer for a coaxial contra-rotating helicopter.

Background

The coaxial reverse dual rotors have the structural characteristics that: two-in + two-out, that is, the whole transmission device has two power input shafts which are respectively driven by two engines or motors, and two power output shafts output power outwards. The two power input shafts drive two coaxially sleeved power output shafts through two independent reduction gear mechanisms, and each power output shaft is connected with a rotor wing, so that a technical form of coaxial reverse double-rotor wing driving is formed. Because the two power output shafts are coaxially (called as coaxial) installed, the rotors are driven to rotate in opposite directions during operation, so that the reaction torques generated by the two rotors are mutually offset due to the opposite directions, and a tail rotor is not needed to be arranged to balance the reaction torques of the rotors. Furthermore, because dual rotors are used, the rotor size (disk diameter) required to deliver the same power can be much smaller than that of a single rotor. Therefore, compared with the two technical platforms, the unmanned aerial vehicle manufactured based on the coaxial reverse dual-rotor technology can be made smaller in overall size.

Most of the existing unmanned helicopters with double rotors coaxial and reverse propellers adopt a speed reducer consisting of a driving bevel gear and two driven bevel gears to realize double rotors coaxial and reverse rotation, for example, CN 207644638U discloses a coaxial and reverse rotation double-output transmission device and an unmanned aerial vehicle using the same, wherein the transmission device comprises a main frame, a power input shaft, a power output hub I, a power output hub II and a coupling bevel gear transmission assembly; the power input shaft is arranged in the main frame, the first power output hub is arranged on the power input shaft, and the second power output hub is arranged on the main frame; the power output hub I is provided with a driving bevel gear coaxial with the power output hub I, the power output hub II is provided with a driven bevel gear, and the coupling bevel gear transmission assembly comprises at least two coupling bevel gears meshed with the driving bevel gear and the driven bevel gear and a main frame positioned between the driving bevel gear and the driven bevel gear.

With the development of the coaxial contra-rotating unmanned helicopter towards large-scale and the application of a turboshaft engine, the rotating speed of the engine is increased, and the rotating speed of the rotor wing is reduced, so that a multi-stage gear reducer is required to realize the functions of transmission, reversing and coaxial contra-rotation of double rotor wings. Various planetary reducers are widely applied to helicopters, but the common planetary reducer cannot realize the function of coaxial and reverse rotation of double rotors.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a planetary reducer for a coaxial contra-rotating helicopter, which has the advantages of compact structure and small occupied space of an input shaft.

The invention is realized by the following technical scheme:

a planetary reducer for a coaxial contra-rotating helicopter comprises an intermediate transmission shaft, a primary sun wheel, a plurality of primary planet wheels, a primary inner gear ring, a connecting frame, a plurality of secondary planet wheels, a secondary sun wheel and a secondary planet wheel, wherein the primary sun wheel is fixed at the top of the intermediate transmission shaft, the primary planet wheels are connected with the primary sun wheel in a meshed mode, the primary inner gear ring is meshed with the primary planet wheels, the connecting frame fixedly connects the primary inner gear ring with an outer shaft, the secondary planet wheels are coaxially arranged with the primary planet wheels, the secondary sun wheel is coaxially arranged above the primary sun wheel in a relatively rotating mode and is in meshed transmission with the secondary planet wheels, the secondary sun wheel is connected with the inner shaft in a transmission mode, the primary planet wheels and the secondary planet wheels are coaxially arranged in a one-.

In the technical scheme, an inner sub-opening 21 is formed at the lower end of the secondary sun gear, and a thrust bearing 23 is arranged between the inner sub-opening and the intermediate transmission shaft positioned below the inner sub-opening.

In the technical scheme, the upper surface of the secondary sun gear is connected with the lower end of the inner shaft through a flange type bolt.

In the technical scheme, the upper part of the middle transmission shaft is provided with a convex ring, and the outer surface of the convex ring is provided with a spline or a crowned tooth so as to be in transmission connection with the first-stage sun gear.

In the technical scheme, the upper surface and the lower surface of the secondary sun wheel form a ring groove.

In the technical scheme, the gear ratio of the primary planet gear and the primary inner gear ring of the speed reducer is equal to the gear ratio of the secondary planet gear and the secondary sun gear, so that the output rotating speeds of the primary inner gear ring and the secondary sun gear are completely the same and the rotating directions are opposite.

In the technical scheme, the lower end of the middle transmission shaft is fixedly provided with a bevel gear and a bevel gear shaft matched with the bevel gear, and the power end of the bevel gear shaft is fixedly connected with the engine through a coupler correspondingly.

In the technical scheme, the middle transmission shaft is provided with a lower flange limiting the bevel gear, the upper part of a central hole of the bevel gear is in interference fit with the middle transmission shaft, the middle part of the central hole of the bevel gear is in spline fit with the middle transmission shaft, and the lower part of the central hole of the bevel gear is in transition fit with the middle transmission shaft.

In the technical scheme, the shaft intersection angle of the bevel gear and the bevel gear shaft is 80-90 degrees.

In the above technical solution, the intermediate transmission shaft is tubular.

The invention has the advantages and beneficial effects that:

the speed reducer of the invention is provided with a group of primary planetary gear trains, which comprise a sun gear, a plurality of planetary gears and an inner gear ring; a group of secondary planetary gear trains comprises a sun gear and a plurality of planetary gears, and is not provided with an inner gear ring. The reducer has a fixed planet carrier, and is shared by a primary planetary gear train and a secondary planetary gear train. The two-stage planet gears of the reducer are equal in number and are respectively connected together to form a plurality of groups of duplicate gears which are then connected with the fixed planet carrier. The primary planet gear system of the speed reducer is output by an inner gear ring, and the inner gear ring is connected with an outer shaft through a connecting frame so as to drive the outer shaft to rotate in one direction. The secondary planetary gear system of the reducer is output by a sun gear which is connected with the inner shaft so as to drive the inner shaft to rotate in the opposite direction. The upper part of the middle transmission shaft is provided with a group of drum-shaped external teeth, the internal teeth of the sun gear are identical in tooth number and are in transmission connection through meshing of the internal teeth and the external teeth, and the gear ratio of the primary planet gear and the primary inner gear ring of the speed reducer is equal to the gear ratio of the secondary planet gear and the secondary sun gear, so that the output rotating speeds of the primary inner gear ring and the secondary sun gear are identical in size and opposite in rotating direction, and the rotation of the double-rotor coaxial counter-rotating propeller is.

Drawings

Fig. 1 is a schematic structural view of a planetary reducer for a coaxial contra-rotating helicopter according to the present invention.

FIG. 2 is a schematic view of the lower end power input structure of the middle transmission shaft of the planetary reducer for the coaxial contra-rotating helicopter.

For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the present invention is further described below with reference to specific examples.

Example one

The invention relates to a planetary reducer for a coaxial contra-rotating helicopter, which comprises an intermediate transmission shaft 12, a primary sun gear 1 fixed at the top of the intermediate transmission shaft, a plurality of, such as three or four primary planet gears 2 meshed with the primary sun gear, a primary inner gear ring 3 meshed with the primary planet gears, a connecting frame 6 fixedly connecting the primary inner gear ring with an outer shaft, a plurality of secondary planet gears 4 coaxially arranged with the primary planet gears, a secondary sun gear 5 which can be relatively and rotatably coaxially arranged above the primary sun gear and is meshed with the secondary planet gears for transmission, the secondary sun gear is in transmission connection with the inner shaft, and the upper ends and the lower ends of the primary planet gears and the secondary planet gears which are arranged in a one-to-one up-down correspondence and coaxial manner are respectively in rotatable connection with a fixed planet carrier 9. The gear ratio of the primary planet gear and the primary inner gear ring of the reducer is equal to that of the secondary planet gear and the secondary sun gear, so that the output rotating speeds of the primary inner gear ring and the secondary sun gear are completely the same and the rotating directions are opposite. The planet carrier is fixed with the shell, the secondary planet wheel is a duplex planet gear, and the center of the primary planet wheel is provided with an internal tooth pattern matched with the external tooth pattern at the lower end of the secondary planet wheel to realize meshing positioning.

Preferably, the central transmission shaft and the inner shaft are both hollow tubular, and the outer shaft is coaxially arranged outside the inner shaft in a relatively rotatable manner. .

An inner sub-opening 21 is formed at the lower end of the secondary sun gear, a thrust bearing 23 is arranged between the inner sub-opening and the middle transmission shaft positioned below the inner sub-opening, and the upper surface of the secondary sun gear is connected with a flange type bolt at the lower end of the inner shaft. The bearing is positioned through a retaining shoulder in an inner hole of the secondary sun gear, and the bearing is arranged between the secondary sun gear and the intermediate transmission shaft.

Meanwhile, a through hole is formed in the middle of the secondary sun gear, and a protruding part is formed in the center of the inner shaft and is inserted into the through hole in a matching mode to achieve positioning, so that connection is firmer. The upper and lower surfaces of the secondary sun gear are formed with annular grooves 22. The effect is that the weight is reduced, can also save oil, and some holes are beaten to the recess inside, can make the oil flow to bearing 23 or the meshing department of one-level sun gear and planet wheel.

Furthermore, a convex ring 24 is formed on the upper portion of the middle transmission shaft, splines or crowned teeth are formed on the outer surface of the convex ring to be in transmission connection with the primary sun gear, namely, a group of crowned external teeth are formed on the upper portion of the middle transmission shaft, a group of internal teeth are formed inside the sun gear, the internal teeth and the internal teeth are identical in tooth number and are in transmission connection through meshing of the internal teeth and the external teeth, a bearing is arranged on the upper portion of the convex ring, and an inner opening is formed on the lower surface of the secondary sun gear to embed the bearing. Meanwhile, a bearing is arranged at the lower end part between the outer shaft and the inner shaft so as to ensure that the outer shaft and the inner shaft rotate smoothly relative to each other.

Example two

The lower end of the middle transmission shaft is fixedly provided with a bevel gear 11 and a bevel gear shaft 10 matched with the bevel gear, and the power end of the bevel gear shaft is fixedly connected with the engine through a coupler correspondingly. The middle transmission shaft is provided with a lower flange 15 for limiting the bevel gear, the upper part of a central hole of the bevel gear is in interference fit with the middle transmission shaft, the middle part of the central hole of the bevel gear is in spline fit with the middle transmission shaft, and the lower part of the central hole of the bevel gear is in transition fit with the middle transmission shaft. The shaft intersection angle of the bevel gear and the bevel gear shaft is 80-90 degrees. Namely, the shaft intersection angle of the pair of bevel gears can be 90 degrees or not, so that the input shaft can be inclined in different directions to adapt to different installation positions of the engine; or the output shaft of the speed reducer inclines at a certain angle in different directions. The transmission function of movement and power is realized, different shaft intersection angles can be provided, such as 90-degree shaft intersection angle, forward inclination or backward inclination with a certain angle, such as 3-10-degree inclination arrangement, and the inclination of the output shaft in different directions can be realized.

The bevel gear and the intermediate transmission shaft are connected in a three-section type connection mode, and the bevel gear and the intermediate transmission shaft are composed of a spline connection part, a cylindrical surface interference fit part and a cylindrical surface transition fit part. Under the condition of using the same bevel gear and the intermediate transmission shaft, the torque and the bending moment can be borne by different connecting structures, the stress concentration of the intermediate transmission shaft is reduced, the rigidity of the bevel gear is improved, and the tooth surface contact of the bevel gear is better.

Specifically, as shown, when the bevel gear shaft and bevel gear are engaged, the force applied by the bevel gear can be reduced to three forces at the midpoint of the tooth width, one horizontal leftward force F1, one vertical downward force F2, and one outward force Ft perpendicular to the plane of the paper. The bending moment generated by F1 is borne by the cylindrical interference fit part II, the bending moment generated by F2 is borne by the cylindrical transition fit part III, and the torque generated by Ft is borne by the spline I. Therefore, the stress of the connecting part of the intermediate transmission shaft is dispersed, the support rigidity of the bevel gear is better, and the bevel gear is not easy to deform.

The middle transmission shaft is used for transmitting the power of the input shaft of the speed reducer to the upper rotor and the lower rotor of the coaxial contra-rotating helicopter, namely correspondingly transmitting the power to the inner shaft and the outer shaft, so that the conversion of the rotating speed and the moving direction is realized, and the upper rotor and the lower rotor rotate reversely at the same speed. A pair of bevel gears are used as a first-stage transmission mechanism of the speed reducer, the tooth system of the first-stage transmission mechanism can be Greenson system tapered teeth or Clinberg system high teeth, and the rotation direction of the bevel gears can be left-handed or right-handed according to the rotation direction of an input shaft.

The planetary reducer of the double-rotor coaxial contra-rotating helicopter is used for realizing the functions of transmission, reversing and double-rotor coaxial contra-rotating, has different intersection angles, can adapt to different installation positions of an engine, or realizes that the output shaft of the reducer inclines to a certain angle in different directions. The transmission of intermediate drive shaft and bevel gear comprises spline connection part, face of cylinder interference fit part and face of cylinder transition fit part, effectively improves its atress distribution, uses under the condition of the same bevel gear and intermediate drive shaft, can make moment of torsion and moment of flexure bear by different connection structure, reduces the atress of intermediate drive shaft and concentrates to improve bevel gear's rigidity, make bevel gear's flank of tooth contact better.

Spatially relative terms, such as "upper," "lower," "left," "right," and the like, may be used in the embodiments for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatial terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "lower" can encompass both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Moreover, relational terms such as "first" and "second," and the like, may be used solely to distinguish one element from another element having the same name, without necessarily requiring or implying any actual such relationship or order between such elements.

The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims

1. A planetary reducer for a coaxial contra-rotor helicopter, characterized in that: the planetary gear comprises an intermediate transmission shaft, a primary sun gear fixed at the top of the intermediate transmission shaft, a plurality of primary planet gears connected with the primary sun gear in a meshed mode, a primary inner gear ring meshed with the primary planet gears, a connecting frame fixedly connected with the primary inner gear ring and an outer shaft, a plurality of secondary planet gears coaxially arranged with the primary planet gears, and a secondary sun gear which can be coaxially arranged above the primary sun gear in a relatively rotating mode and is in meshed transmission with the secondary planet gears, wherein the secondary sun gear is connected with the inner shaft in a transmission mode, the primary planet gears and the secondary planet gears are coaxially arranged in a one-to-one up-down correspondence mode, and the upper end and the lower end of each coaxial planet gear are rotatably connected with a fixed planet carrier respectively.

2. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: an inner sub-opening is formed at the lower end of the secondary sun gear, and a thrust bearing is arranged between the inner sub-opening and the intermediate transmission shaft positioned below the inner sub-opening.

3. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: the upper surface of the secondary sun gear is connected with the lower end of the inner shaft through a flange type bolt.

4. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: a convex ring is formed on the upper part of the middle transmission shaft, and a spline or a crowned tooth is formed on the outer surface of the convex ring to be in transmission connection with the first-stage sun gear.

5. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: the upper surface and the lower surface of the secondary sun wheel form a ring groove.

6. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: the gear ratio of the primary planet gear and the primary inner gear ring of the reducer is equal to that of the secondary planet gear and the secondary sun gear, so that the output rotating speeds of the primary inner gear ring and the secondary sun gear are completely the same and the rotating directions are opposite.

7. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: the lower end of the middle transmission shaft is fixedly provided with a bevel gear and a bevel gear shaft matched with the bevel gear, and the power end of the bevel gear shaft is fixedly connected with the engine through a coupler correspondingly.

8. A planetary reducer for a coaxial contra-rotor helicopter according to claim 7, characterized in that: the middle transmission shaft is provided with a lower flange for limiting the bevel gear, the upper part of a center hole of the bevel gear is in interference fit with the middle transmission shaft, the middle part of the center hole of the bevel gear is in spline fit with the middle transmission shaft, and the lower part of the center hole of the bevel gear is in transition fit with the middle transmission shaft.

9. A planetary reducer for a coaxial contra-rotor helicopter according to claim 8, characterized in that: the shaft intersection angle of the bevel gear and the bevel gear shaft is 80-90 degrees.

10. A planetary reducer for a coaxial contra-rotor helicopter according to claim 1, characterized in that: the middle transmission shaft is tubular.