Planetary gear
The planetary gear design is simplified by using two central wheels and spherical rollers as connecting elements, addressing manufacturing complexity and load distribution issues, enhancing load-bearing capacity and reducing axial size and noise.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- FEDERALNOE GOSUDARSTVENNOE BYUDZHETNOE OBRAZOVATELNOE UCHREZHDENIE VYSSHEGO OBRAZOVANIYA IZHEVSKIJ GOSUDARSTVENNYJ TEKHNICHESKIJ UNIV IMENI M T KALASHNIKOVA
- Filing Date
- 2025-12-05
- Publication Date
- 2026-06-30
AI Technical Summary
Existing planetary gear designs face challenges with high manufacturing complexity, large volume of gear-cutting work, low load-bearing capacity, and increased axial size due to the use of toothed cardans and spherical bearings, which complicate the design and reduce efficiency.
The design simplifies the planetary gear by using two central wheels with radial clearance and rollers with spherical surfaces as connecting elements, allowing for manufacturing errors compensation and equalization of load during operation, without adding complex components.
This simplification enhances manufacturability, improves load distribution, and increases load-bearing capacity while reducing the axial size and dynamic load, resulting in smoother operation and reduced noise.
Smart Images
Figure 00000001_ABST
Abstract
Description
[0001] The invention relates to the field of mechanical engineering, in particular to gear transmissions, and can be used in highly loaded mechanical drives with a limited radial dimension.
[0002] A planetary gear is known that contains a sun gear mounted on a toothed cardan, satellites located on axles by means of spherical bearings, a fixed central wheel and a carrier [1].
[0003] Its disadvantages are the large volume of gear-cutting work, which is caused by the presence of a toothed cardan, and low load-bearing capacity (especially with a limited radial size), since each satellite is mounted on the axis by means of one spherical bearing.
[0004] A planetary transmission is known, containing a sun gear, a fixed central wheel, double satellites located on the axles by means of spherical bearings, and a composite carrier, made in the form of a cheek with holes rigidly connected to the output shaft and a self-aligning disk, wherein the disk of the composite carrier is made as a single unit with cylindrical pins installed with a gap in the holes of the cheek of the composite carrier, and with mounting seats for spherical bearings of the axles of the double satellites, on the consoles of which the double satellites are seated by means of spherical bearings [2].
[0005] Its disadvantage is the large axial size due to the increased width of the composite carrier disc, in which high-load-capacity spherical bearings are located.
[0006] Also known is a planetary transmission containing a sun gear, a fixed central wheel installed in the transmission housing by means of connecting elements made in the form of prismatic or cylindrical keys, double satellites, each of which consists of two wheels installed through spherical bearings on a common axis, and a carrier consisting of two rigidly connected cheeks and self-aligning sections with double satellites installed in them (prototype) [3].
[0007] This design is difficult to manufacture and not technologically advanced.
[0008] The objective of this invention is to simplify the design of a planetary gear and increase the level of its manufacturability.
[0009] The solution to the stated problem is achieved in that in a planetary transmission containing a sun gear, a fixed central wheel installed in the transmission housing by means of connecting elements, double satellites, each of which consists of two wheels installed through spherical bearings on a common axis, and a carrier consisting of two rigidly connected cheeks in which the axes of the double satellites are located, the fixed central wheel is made in the form of two central wheels installed in the housing with a radial clearance, and the connecting elements are made in the form of rollers with spherical surfaces at the points of their mating with the housing and the central wheels, wherein the connecting elements are installed in cylindrical grooves of the housing and the central wheels with a clearance.
[0010] The planetary gear design is simplified and its manufacturing efficiency is improved by designing the central gear as two wheels and the connecting elements as rollers with spherical surfaces. This allows for compensation for manufacturing errors in the planetary gear and equalization of the load on the gear meshes during operation, without complicating the carrier design.
[0011] The essence of the invention is explained by the drawings, where Fig. 1 shows a general view of the planetary gear in section, Fig. 2 is a view along A-A in Fig. 1, Fig. 3 is a view along B-B in Fig. 1 of the central wheel, housing and connecting elements, Fig. 4 is a fragment of a general view of the planetary gear in section in the presence of a centering ring (clause 2 of the formula of the invention).
[0012] The planetary gear comprises a sun gear 1, double satellites 2, spherical bearings of the double satellites 3, axles of the double satellites 4, a carrier 5, two central wheels 6, a housing 7, connecting elements 8, a cover 9, high-speed shaft bearings 10, low-speed shaft bearings 11, a rubber centering ring 12 (clause 2 of the formula of the invention).
[0013] Sun gear 1 is integral with the high-speed shaft, and planet carrier 5 is integral with the low-speed shaft so that the planet carrier cheeks are located between the left and right ends of the low-speed shaft. Connecting elements 8 are rollers with spherical surfaces. Cylindrical grooves for mounting connecting elements 8 are provided in housing 7 and central wheels 6.
[0014] The central wheels 6 are mounted in the housing 7 with a radial clearance by means of connecting elements 8. The connecting elements 8 are also mounted in cylindrical grooves of the housing 7 and the central wheels 6 with a clearance. In this case, the two outer spherical surfaces of each connecting element 8 mate with the cylindrical grooves of the central wheels 6, and the middle spherical surface mates with the cylindrical groove of the housing 7.
[0015] The planetary gear assembly is carried out in the following sequence.
[0016] Central wheels 6 are installed in housing 7. Connecting elements 8 are inserted into the grooves of central wheels 6 and housing 7. The left bearing of high-speed shaft 10 is inserted into the mounting seat of planet carrier 5 through its groove. Double satellites 2 assembled with spherical bearings 3 are inserted into the grooves of planet carrier 5. The axes of double satellites 4 are inserted into the holes of planet carrier 5 and into the inner rings of spherical bearings 3 and fixed in them. The satellite block assembled in this way is inserted by axial movement into the low-speed shaft into the housing 7 and into the inner ring of the low-speed shaft bearing 11, which is pre-installed in the housing 7, while the double satellites 2 are brought into engagement with the central wheels 6. The sun gear 1 is inserted with the left end of the high-speed shaft into the inner ring of its bearing 10 and is simultaneously brought into engagement with the double satellites 2. The right bearing of the high-speed shaft 10 is seated in the mounting socket of the planet carrier 5 and simultaneously on the high-speed shaft.The right bearing of the low-speed shaft 11 is installed in the seat of the cover 9, after which the cover 9 is inserted into the housing 7 and at the same time the inner ring of the bearing 11 is seated on the right end of the low-speed shaft.
[0017] To reduce the dynamic load and improve the smooth operation of the planetary gear, it can be equipped with a centering rubber ring 12 (Fig. 4) located between the central wheels 6 and the connecting elements 8.
[0018] To reduce the axial size of the transmission and further simplify its design, the carrier 5 can be made to consist of one cheek, in which the axes of the double satellites 4 are cantilevered.
[0019] The planetary gear works as follows.
[0020] Rotary motion is transmitted from sun gear 1 through double planet gears 2, their spherical bearings 3, double planet gear axles 4, planet carrier 5, and a low-speed shaft integral with it. The load between double planet gears 2 is balanced by the radial clearance between central wheels 6 and housing 7 and by the clearances between their grooves and connecting elements 8, which ensures radial displacement of central wheels 6 and their self-alignment. Uniform load distribution between the two rows of double planet gears 2 is ensured by the angular displacement of connecting elements 8, which allows central wheels 6 to shift circumferentially relative to each other.
[0021] This ensures a highly uniform load distribution across the gear meshes and high load-bearing capacity of the planetary gear. Furthermore, the gearbox does not contain any additional, non-technological elements that complicate the mechanism's design.
[0022] Installing a centering rubber ring on the cylindrical part of the central wheels reduces the dynamic load and noise level of the planetary gear during its operation, and making the carrier consisting of one cheek allows for reducing the axial size of the gear by the thickness of the cheek and simplifying its design.
[0023] SOURCES OF INFORMATION
[0024] 1. Reshetov L.N. Self-aligning mechanisms. Handbook. - M.: Mashinostroenie, 1991. - p. 168, Fig. 8.4.
[0025] 2. Russian Federation Patent No. 2789229 C1, IPC F16H 1 / 32, published 31.01.2023, Bulletin No. 4.
[0026] 3. Auto. date USSR No. 523216, MKI F16H 1 / 48, publ. 07 / 30 / 1976 (prototype).
Claims
1. A planetary transmission comprising a sun gear, a fixed central wheel mounted in the transmission housing by means of connecting elements, double satellites, each of which consists of two wheels mounted through spherical bearings on a common axis, and a carrier consisting of two rigidly connected cheeks in which the axes of the double satellites are located, characterized in that the fixed central wheel is made in the form of two central wheels mounted in the housing with a radial clearance, and the connecting elements are made in the form of rollers with spherical surfaces at the points of their mating with the housing and the central wheels, wherein the connecting elements are installed in cylindrical grooves of the housing and the central wheels with a clearance.
2. A planetary gear according to paragraph 1, characterized in that it is made with a centering rubber ring located between the central wheels and the connecting elements.