CN111692293B

CN111692293B - Speed reducer and lubricating method

Info

Publication number: CN111692293B
Application number: CN201910189880.4A
Authority: CN
Inventors: 杜宜东; 杨思维; 张燕; 苏新生; 蔡智杰; 尹伟杰
Original assignee: Hunan Aviation Powerplant Research Institute AECC
Current assignee: Hunan Aviation Powerplant Research Institute AECC
Priority date: 2019-03-13
Filing date: 2019-03-13
Publication date: 2022-05-31
Anticipated expiration: 2039-03-13
Also published as: CN111692293A

Abstract

The invention provides a speed reducer and a lubricating method. The speed reducer comprises a sun gear, a planetary gear meshed with the sun gear and an output shaft component which is connected to the planetary gear in a rotating mode, the sun gear is provided with an inner cavity arranged along the axial direction of the sun gear, the inner cavity is provided with a first opening and a second opening, and the output shaft component is connected to the end face of the first opening in a rotating mode. Lubricating oil enters the inner cavity from the second opening, and along with the rotation of the sun gear, the lubricating oil moves towards the first opening along the side wall of the inner cavity until being thrown out of the end face of the first opening. The speed reducer provided by the invention has the advantages of simple structure and good lubricating effect.

Description

Speed reducer and lubricating method

Technical Field

The invention relates to the field of speed reducers in general, and particularly relates to a speed reducer with a centrifugal lubricating structure and a lubricating method of the speed reducer.

Background

The sun gear is the primary power and load transmitting component of the helicopter transmission. At present, the sun gear of the reducer which is researched and used in China adopts a structure with equal wall thickness and only has the function of transmitting torque, and the structure has the main defects of larger weight and incapability of lubricating the rotation between the rotor shaft and the sun gear and the gear pair between the sun gear and the planet gear.

Moreover, because the structure of the gear train formed by the sun gear and the planet gear is compact, the arrangement of a lubricating system is very difficult, only splash lubrication or oil-gas lubrication can be adopted between the sun gear and the rotor shaft, and the two lubricating modes can not provide a lubricating effect well.

The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

It is a primary object of the present invention to overcome at least one of the above-mentioned drawbacks of the prior art and to provide a reducer with a centrifugal lubrication structure to solve the problem of poor lubrication effect in the prior art.

Another main object of the present invention is to overcome at least one of the drawbacks of the prior art described above and to provide a method for lubricating a reducer.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

according to an aspect of the present invention, there is provided a speed reducer having a centrifugal lubrication structure, the speed reducer including a sun gear, a planetary gear meshing with the sun gear, and an output shaft member rotatably connected to the planetary gear, the sun gear having an inner cavity provided along an axial direction thereof, the inner cavity having a first opening and a second opening, the output shaft member being rotatably connected to an end surface of the first opening;

lubricating oil enters the inner cavity from the second opening, and along with the rotation of the sun gear, the lubricating oil moves towards the first opening along the side wall of the inner cavity until being thrown out of the end face of the first opening.

According to an embodiment of the present invention, a friction reducing element is provided between the output shaft member and an end surface of the first opening.

According to an embodiment of the present invention, an acute angle is formed between the incident direction of the lubricating oil and the end surface of the second opening.

According to an embodiment of the present invention, the acute angle is 30 ° to 60 °.

According to an embodiment of the present invention, a portion of the sun gear adjacent to the second opening is in a reduced structure.

According to an embodiment of the invention, the side wall of the inner cavity of the sun gear is in the shape of an inverted cone.

According to an embodiment of the invention, the sun gear is of unequal wall thickness.

According to an embodiment of the present invention, the output shaft member is a rotor shaft.

According to an embodiment of the invention, the reducer comprises a stationary ring gear located outside the planet gears, said stationary ring gear meshing with the planet gears.

According to another aspect of the present invention, there is provided a method of lubricating a reduction gear according to any one of the above aspects, wherein lubricating oil enters the inner cavity through the second opening, and the lubricating oil moves toward the first opening along a side wall of the inner cavity as the sun gear rotates until the lubricating oil is thrown off an end surface of the first opening.

According to the technical scheme, the speed reducer with the centrifugal lubricating structure has the advantages and positive effects that:

compared with the prior art, the speed reducer with the centrifugal lubricating structure has the advantages that the structure is simple, and the lubricating effect is good.

In addition, because a certain amount of lubricating oil always exists in the inner cavity of the sun gear, the lubricating oil can delay the occurrence of the dry grinding state between the sun gear and the antifriction element and the occurrence of the dry grinding state between the sun gear and the planetary gear pair, and the dry running capability of the main speed reducer is effectively improved.

Drawings

The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

FIG. 1 is a partial cross-sectional view of a retarder according to an exemplary embodiment.

FIG. 2 is a cross-sectional view of a sun gear shown according to an exemplary embodiment.

Wherein the reference numerals are as follows:

1. sun gear

11. Inner cavity

111. First opening

112. Second opening

12. Necking structure

2. Planetary gear

3. Output shaft member

4. Wear reducing element

5. Bearing assembly

6. Fixed gear ring

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed description will be omitted.

Although relative terms, such as "upper" and "lower," may be used in this specification to describe one element of an icon relative to another, these terms are used in this specification for convenience only, e.g., in accordance with the orientation of the examples described in the figures. It will be appreciated that if the device of the icon were turned upside down, the element described as "upper" would become the element "lower". The terms "a," "an," "the," and "said" are used to indicate the presence of one or more elements/components/etc.; the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. other than the listed elements/components/etc.; the terms "first," "second," "third," and "fourth," etc. are used merely as labels, and are not limiting as to the number of their objects.

Referring to FIG. 1, a reducer having a centrifugal lubrication configuration that embodies principles of the present invention is representatively illustrated in FIG. 1. In this exemplary embodiment, the reducer with a centrifugal lubrication structure proposed by the present invention is explained taking a transmission system of a helicopter as an example. It should be understood by those skilled in the art that the speed reducer having the centrifugal lubricating structure is applied to other fields, and various modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below while remaining within the scope of the present invention.

FIG. 1 is a partial cross-sectional view of a retarder according to an exemplary embodiment. FIG. 2 is a cross-sectional view of a sun gear shown according to an exemplary embodiment.

The structure, connection mode and functional relationship of the main components of the speed reducer with centrifugal lubrication structure according to the present invention will be described in detail with reference to the drawings.

As shown in fig. 1, the present invention provides a reduction gear having a centrifugal lubrication structure, which includes a sun gear 1, planetary gears 2, an output shaft member 3, and a fixed ring gear 6. The planetary gear 2 is meshed with the sun gear 1 and is driven by the sun gear 1 to rotate and revolve. The output shaft member 3 may be rotatably connected to the planetary gear 2 through a bearing 5, and the output shaft member 3 is rotated by rotation and revolution of the planetary gear 2, and at the same time, the output shaft member 3 is rotatably connected to one end surface of the sun gear 1. The fixed ring gear 6 is located outside the pinion gears 2 and meshes with the pinion gears 2. Accordingly, the central axis of the fixed ring gear 6 coincides with the central axis of the sun gear 1 and the revolution center line of the planetary gear 2.

In addition, since the reduction gear is compact in structure, the gap between the end surface of the sun gear 1 and the output shaft member 3 is small and the rotation speed is different between the two, and in order to avoid friction between the two in extreme operating conditions, an anti-friction element 4, such as an anti-friction pad, is further provided between the end surface of the sun gear 1 and the output shaft member 3.

It will be appreciated that in this embodiment the output shaft member 3 may be a rotor shaft and the reducer may be a final reducer in a helicopter transmission, although the reducer and the output shaft member 3 may also be used in other applications.

With continued reference to fig. 1 and 2, the sun gear 1 has an inner cavity 11 disposed along an axial direction thereof, and the inner cavity 11 has a first opening 111 and a second opening 112. In addition, the part of the sun gear 1 close to the second opening 112 is in the necking structure 12, so that the inner diameter of the necking structure 12 is smaller than that of the other part of the inner cavity 11, and the lubricating oil entering the inner cavity 11 is prevented from sliding out of the second opening 112. The lubricant can be injected into the inner cavity 11 from the second opening 112 through a nozzle or other means, wherein the lubricant can be injected at an acute angle with the end surface of the second opening 112, and preferably, the acute angle can be 30 degrees to 60 degrees, such as 30 degrees, 40 degrees, or 60 degrees. When a certain angle exists between the incident direction of the lubricating oil and the end surface of the second opening 112, the lubricating oil can be ensured to contact the side wall of the inner cavity 11 in the shortest time, and the initial kinetic energy of the lubricating oil can be utilized to the maximum extent, so that the lubricating oil can climb to the first opening 111 rapidly, and the lubricating effect is achieved.

The flow path of the lubricating oil is described in detail below with reference to fig. 1: as shown in the figure, the arrow direction is a flow path of the lubricating oil, after the lubricating oil enters the inner cavity 11, the lubricating oil is sprayed on the side wall of the inner cavity 11, and since the inner diameter of the throat structure 12 is smaller than the inner diameter of the whole inner cavity 11, the lubricating oil cannot flow out of the second opening 112 after entering the inner cavity 11. Meanwhile, as the lubricating oil entering the inner cavity 11 has initial kinetic energy in a certain upward direction, along with the rotation of the sun gear 1, the lubricating oil climbs towards the first opening 111 along the side wall of the inner cavity 11 until being thrown out of the end face of the first opening 111. The lubricating oil thrown out from the end surface of the first opening 111 plays a role of lubricating the sun gear 1 and the friction reducing element 4, and also lubricates the gear pair between the sun gear 1 and the planetary gear 2.

In other embodiments, in order to increase the climbing speed of the lubricating oil entering the inner cavity 11 and to throw the lubricating oil out of the end surface of the first opening 111 as soon as possible, the side wall of the inner cavity 11 of the sun gear 1 is designed to be an inverted cone. Of course, the side walls of the interior 11 can also be designed in other shapes.

In addition, the speed reducer provided by the invention not only ensures the lubricating effect of the sun gear 1 and the antifriction elements 4 under the condition that the lubricating oil pressure operates normally, but also can delay the occurrence of the dry-grinding state when the dry-running state (the lubricating oil pressure is 0) of the speed reducer occurs.

Specifically, taking a main speed reducer of a helicopter as an example, when a lubricating system of the main speed reducer fails, the working temperature of main rotating parts is rapidly increased, the speed reducer rapidly enters a dry running state, and the speed reducer can be damaged in a short time, completely loses the power transmission function and causes a catastrophic accident. In the field of helicopters, in order to ensure the viability of helicopters, the main reducer still can work for at least 30min under specified conditions when the lubrication system of the main reducer fails, so that the helicopter can rapidly evacuate from a dangerous environment and safely land in the time, and therefore, after the lubrication system fails, how to prolong the normal working time of the main reducer is particularly important.

In the prior art, the lubrication of a main speed reducer is mostly performed by adopting splash lubrication or oil-gas lubrication, when a lubrication system fails, the supply of lubricating oil is immediately stopped, and the dry running state of the main speed reducer occurs quickly. However, in the speed reducer of the present invention, the lubricating oil rises through the inner cavity 11 by the centrifugal rotation of the sun gear 1, thereby achieving the lubricating effect. When the pressure of the lubricating oil is reduced to 0, a certain amount of lubricating oil still exists in the inner cavity 11 of the sun gear 1, and the lubricating oil can continuously climb to the end face of the first opening 111, so that the dry grinding state between the sun gear 1 and the antifriction element 4 is delayed, the dry grinding state between the sun gear 1 and the planetary gear 2 is delayed, and the dry running capability of the main speed reducer is effectively improved.

Further, in the present embodiment, in order to reduce the weight of the sun gear 1, the sun gear 1 of the reduction gear according to the present invention has an unequal thickness, and for example, as shown in fig. 2, the thickness of the non-meshing region of the sun gear 1 is smaller than the thickness of the meshing region.

It should be noted herein that the reduction gear having a centrifugal lubrication structure shown in the drawings and described in the present specification is only one example employing the principles of the present invention. It will be clearly understood by those skilled in the art that the principles of the present invention are not limited to any of the details or any of the components of the apparatus shown in the drawings or described in the specification.

The invention also provides a method for lubricating a speed reducer, wherein the speed reducer can be any one of the embodiments. The lubricating oil enters the inner cavity 11 from the second opening 112, and along with the rotation of the sun gear 1, the lubricating oil moves to the first opening 111 along the side wall of the inner cavity 11 until being thrown out of the end face of the first opening 111. The thrown lubricating oil can lubricate the sun gear 1 and the output shaft member 3 and can lubricate a gear pair between the sun gear 1 and the planet gear 2.

In addition, the part of the sun gear 1 close to the second opening 112 is in the necking structure 12, so that the inner diameter of the necking structure 12 is smaller than that of the other part of the inner cavity 11, and the lubricating oil entering the inner cavity 11 is prevented from sliding out of the second opening 112.

In addition, in order to increase the climbing speed of the lubricating oil entering the inner cavity 11 and to achieve the lubricating effect by being thrown out of the end surface of the first opening 111 as soon as possible, the side wall of the inner cavity 11 of the sun gear 1 may be designed to be an inverted cone. Of course, the side walls of the interior 11 can also be designed in other shapes.

In summary, the speed reducer with the centrifugal lubrication structure provided by the invention utilizes the operation of the sun gear 1, and the lubricating oil realizes the lubrication of the parts of the speed reducer through the inner cavity 11 of the sun gear 1.

In addition, when the lubricating system is normal, because a certain amount of lubricating oil always exists in the inner cavity 11 of the sun gear 1, the lubricating oil can delay the occurrence of the dry grinding state between the sun gear 1 and the antifriction elements 4 and the occurrence of the dry grinding state of the gear pair of the sun gear 1 and the planet gears 2, and the dry running capability of the main speed reducer is effectively improved.

It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the description. The invention is capable of other embodiments and of being practiced and carried out in various ways. The foregoing variations and modifications fall within the scope of the present invention. It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute alternative aspects of the present invention. The embodiments described in this specification illustrate the best mode known for carrying out the invention and will enable those skilled in the art to utilize the invention.

Claims

1. A speed reducer for use as a final drive in a helicopter transmission system, said speed reducer comprising a sun gear, a planetary gear in meshing engagement with said sun gear, and an output shaft member rotatably connected to said planetary gear, wherein said sun gear has an internal cavity disposed axially thereof, said internal cavity having a first opening and a second opening, said output shaft member being rotatably connected to an end surface of said first opening, wherein said output shaft member is a rotor shaft;

lubricating oil enters the inner cavity from the second opening, and along with the rotation of the sun gear, the lubricating oil moves to the first opening along the side wall of the inner cavity until being thrown out of the end face of the first opening;

wherein an acute angle is formed between the incident direction of the lubricating oil and the end surface of the second opening;

the part of the sun gear close to the second opening is of a necking structure;

the side wall of the inner cavity of the sun gear is in an inverted cone shape.

2. A speed reducer according to claim 1, wherein a friction reducing element is provided between the output shaft member and an end face of the first opening.

3. A decelerator according to claim 1, wherein the acute angle is 30 ° to 60 °.

4. A reducer according to claim 1 or claim 2, in which the sun gear is of unequal wall thickness.

5. A reducer according to claim 1 or claim 2, in which the reducer includes a fixed ring gear located outside the planet gears, the fixed ring gear meshing with the planet gears.

6. A method of lubricating a speed reducer according to any one of claims 1 to 5, wherein the speed reducer has a structure in which lubricating oil enters the cavity through the second opening, and the lubricating oil moves along the side wall of the cavity toward the first opening until being thrown off the end face of the first opening as the sun gear rotates.