Double-sun-gear planetary gear train differential mechanism with planetary gear pairs connected in meshed mode

Abstract

The utility model discloses a double-sun-gear planetary gear train differential mechanism, which is characterized in that a plurality of pairs of planetary gear pairs supported by pivot holes of a planetary gear carrier of a planetary gear train are arranged on the peripheries of two coaxial sun gears of the planetary gear train, and the planetary gear pairs are mutually meshed and connected; different from a common planetary differential mechanism, all pairs of planetary gear pairs are mutually independent, namely, the planetary gear pairs are not mutually meshed and connected. According to the double-sun-gear planetary differential mechanism, under the static balance of acting force borne by each planetary gear, two symmetrical meshing points formed equally divide normal force, and a planetary gear carrier only acts centripetal radial force on the planetary gears. Therefore, the stress state of internal components of the planetary gear train differential mechanism is improved, and the bearing capacity of the differential mechanism is increased. They are suitable for terminal drive systems of ground wheeled vehicles.

Description

[0001] This utility model claims priority to Chinese Patent Application No. 202411333262X, filed on September 24, 2024, entitled "Double Sun Gear Planetary Gear Differential for Intermeshing Connection Between Pairs of Planetary Gears", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This utility model relates to some planetary gear differentials in the terminal transmission system of ground wheeled vehicles, and also to some mechanical limited-slip differentials. Background Technology

[0003] A differential is a two-degree-of-freedom gear transmission system. It is commonly used in wheeled vehicles to control the differential speed and torque between the drive wheels and the drive axle. This allows the drive wheels and drive axle to rotate at different speeds while cornering or driving on inhomogeneous road surfaces, maintaining pure rolling contact with the road surface (David Shearer first used a differential on a motor vehicle in Australia in 1897—later popularly known as a "pumpkin"). It also prevents the final driveline from experiencing "power saturation" ("wind-up") in full-time drive mode, and facilitates operation on uneven road surfaces. μ The differential (-split) transmits the engine's driving torque to the drive wheels and drive shaft as needed. A differential consists of multiple pairs of planetary gears, but generally, each pair of planetary gears is independent of the others, such as CN204099536U, CN 204628482U, CN 105276132A, CN 211693422U, and CN 220286342U. Utility Model Content

[0004] This utility model provides a "dual sun planetary differential with meshing connections between pairs of planetary gears", comprising: a left or front sun gear 1 and a right or rear sun gear 2—both sun gears are connected to the differential output shaft, and several pairs (1,2,...) of planetary gears meshing with each other. i ,…, n Planetary gear pair 3 (where: i —The ordinal number of the planetary gear pair is a positive integer. n—The number of planetary gear pairs (a positive integer greater than 1)—They overlap and mesh on a portion of the width (rotating in opposite directions) and mesh with the sun gears on their adjacent sides on the remaining width of the total width (i.e., each planetary gear pair meshes with and connects to the sun gears on both sides), and the planetary gear carrier 4—connected to the differential input shaft, with each planetary gear's pivot freely rotating within its respective bore. The gears are primarily spur gears or helical gears and other transmission gears (including gearless drives, such as friction traction drives). When the planetary gear carrier rotates (input torque), the sun gears on both sides rotate at the same speed relationship as other types of open (standard) differentials. ω S(L,F) + ω S(R,R) =2× ω C Rotation (output torque), where: ω S(L,F) —Speed ​​of the left or front sun gear, in [rad / s], ω S(R,R) —Right or rear sun gear speed, ω C — Planetary gear carrier speed.

[0005] The feature of this utility model is that each pair of planetary gear pairs is meshed and connected. i and( i +1)| i=1,2,…,(n-1),n(n+1≡1) This results in the forces acting on each planetary gear being evenly distributed at the two symmetrical meshing points under static equilibrium, with the planetary gear carrier only exerting a centripetal radial force on it. This improves the stress state of the internal components of the differential and increases the load-bearing capacity of the differential.

[0006] One objective of this invention is to provide novel dual-sun gear planetary differentials that improve upon the existing technology. Another objective is to provide novel limited-slip planetary differentials with improved technical performance. A further objective is to provide novel limited-slip planetary differentials that are universally applicable to inter-wheel differentials (driven non-steered axles and driven steered axles) and inter-axle differentials / center differentials / transfer cases in vehicles, providing differential speed and torque. A particular objective is to provide novel planetary differentials and limited-slip planetary differentials that are better suited for heavy-duty (ultra-heavy-duty) off-road vehicle configurations, such as inter-axle differentials within the TATRA central back-bone tube frame. Attached Figure Description

[0007] Figure 1 This is a schematic structural perspective view of the present invention. In the figure: 1—left or front sun gear, 2—right or rear sun gear, 3—planetary gear pairs, 4—planetary gear carrier. Figure 1 -1 is a schematic axial view of the structure of this utility model;

[0008] Figure 2 A schematic perspective view of a differential with limited-slip function in helical cylindrical gear transmission;

[0009] Figure 3 The width of the overlapping meshing of the two planetary gears in each planetary gear pair of the differential, and the interlocking meshing portion between each pair of planetary gear pairs, is located on both sides of it;

[0010] Figure 4 for Figure 1 , Figure 2 and Figure 3 A schematic diagram of a limited-slip differential, formed by circumferentially dividing the sun gear and its output connection structure, and then adding a helical spline transmission connection. In the diagram: 5—left or front helical spline transmission mechanism; 6—right or rear helical spline transmission mechanism;

[0011] Figure 5 for Figure 1 , Figure 2 and Figure 3 The diagram illustrates the schematic principle of a differential or limited-slip differential suitable for a central transfer case, characterized by uneven torque output due to the different numbers of sun teeth on both sides (i.e., different reference circles or pitch circles). z S(F(L)) < z S(R(R)) ): 1-1—Front small pitch circle or pitch circle sun gear; 2-1—Rear large pitch circle or pitch circle sun gear;

[0012] Figure 6 for Figure 1 , Figure 2 and Figure 3 The middle part is formed by replacing the external meshing of the sun gear with an internal ring gear, similar to... Figure 5 A schematic diagram of a differential or limited-slip differential with uneven torque output function. In the diagram: 2-2—Internal gear ring;

[0013] Figure 7 for Figure 1 , Figure 2 and Figure 3 A schematic perspective view of a differential or limited-slip differential where the planetary gear pairs are disengaged from each other, meaning each pair of planetary gear pairs is independent. (Figure 3-1—) i ( i =1,2,…, n For planetary gear pairs, 3-2—( i +1)( i =1,2,…, n (n+1≡1) For planetary gear pairs.

[0014] The above figures are only some embodiments of this utility model. Those skilled in the art can obtain other figures based on these figures without any creative effort. Detailed Implementation

[0015] To make the technical solution and beneficial effects of this utility model more apparent and understandable, a detailed description is provided below by listing specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0016] The double sun gear planetary gear differential of this invention, in which the planetary gear pairs mesh with each other, can be applied to passenger cars, commercial vehicles, and other wheeled vehicles.

[0017] The present invention will be further described below with reference to the accompanying drawings, which provide some embodiments.

[0018] See Figure 1 and Figure 1-1 The double sun gear planetary differential shown generally consists of a left or front sun gear 1 and a right or rear sun gear 2, and several pairs of (1, 2, ...) i ,…, n The planetary gear pair 3 and the planetary gear carrier 4 are composed of a planetary gear set 3 and a planetary gear carrier 4. When the planetary gear carrier rotates (input torque), the sun gears on both sides rotate at an angle of ( ω S(L,F) + ω S(R,R) =2× ω C The rotational speed is related to the output torque. The planetary gear pairs of this differential are meshed and connected to each other. i and( i +1)| i=1,2,…,n(n+1≡1) This results in the forces acting on each planetary gear being evenly distributed at the two symmetrical meshing points under static equilibrium, and the planetary gear carrier only exerting a centripetal radial force on it. Therefore, the stress state of the internal components of the differential is improved, thereby increasing the load-bearing capacity of the differential.

[0019] See Figure 2 The double sun gear planetary gear differential shown has a helical spur gear drive instead of a spur gear drive. The axial force generated by these helical spur gears can be used to generate additional frictional torque, which gives the differential a "torque sensing" limited-slip function, thus transforming it into a mechanical limited-slip differential.

[0020] See Figure 3 The double sun gear planetary differential shown in the figure has a "partial width" of meshing between two planetary gears in each pair of planetary gear pairs, which changes from the central position of the total width to the two sides of each pair. The remaining width of the total width that meshes with the sun gear changes from the two sides of each pair to the central position of the total width.

[0021] See Figure 4The dual-sun-gear planetary differential shown has a helical spline transmission mechanism 5 and 6 between each of its two sun gears and their respective output connection structures (generally internal straight splines). That is, the two sun gears and their respective output connection structures are circumferentially divided and then connected by a helical spline transmission mechanism. The helical splines on both sides have different directions of rotation, one to the left and one to the right, and are opposite to the direction of rotation of their respective meshing sun helical gears. This forms a "torque-sensing" limited-slip differential (TorSen LSD). Thus, the limited-slip function is "enhanced" for open differentials with spur gear drives and "strengthened" for limited-slip differentials with helical gear drives.

[0022] See Figure 5 The planetary differential shown has the following tooth counts for its two sun gears: 1-1 (left is the front) and 2-1 (right is the rear). z Sun Different, that is z S(F(L)) < z S(R(R)) (or possible) z S(R(R)) < z S(F(L)) At this point, the rotation axes of the two planetary gears in each planetary gear pair are on different distribution circles; and the ratio of the pitch circle or pitch circle of the sun gears with different numbers of teeth on both sides is... d ( ′ ) (S,F) : d ( ′ ) (S,R) They were determined to be pre-split with uneven torque output for the central transfer case, to distribute uneven torque to the front and rear drive shafts (drive axles), such as 40% front: 60% rear; where: z S(F(L)) —Number of teeth and unit of the front sun gear[1], z S(R(R)) —Number of teeth on the rear sun gear, d ( ′ ) (S,F) —The pitch circle or index circle of the front sun gear, in meters or millimeters. d ( ′ ) (S,R) —The pitch circle or pitch circle of the rear sun gear.

[0023] See Figure 6 The planetary differential shown has one of its externally meshing sun gears transformed into an internally meshing ring gear 2-1, thus converting the differential into a compound planetary gear mechanism. The torque ratio between the sun gear and the ring gear is the ratio of the pitch circle (or pitch circle) of the sun gear to that of the ring gear. d ( ′ ) (Sun,F) : d ( ′ ) (Ring,R) (Generally 2:3), thus forming a transfer case with a preset torque ratio for use in the central transfer case, wherein: d ( ′ ) (Sun,F) —The pitch circle or index circle of the front sun gear d ( ′ ) (Ring,R) —The pitch circle or index circle of the rear gear ring. At this time, the gear ring can also serve as the input shaft or input end of the differential, while the planetary gear carrier serves as an output shaft or output end accordingly.

[0024] See Figure 7 The double sun gear planetary differential shown has planetary gear pairs 3-1 and 3-2 disengaged from each other, meaning that each pair of planetary gear pairs operates independently. At this time, the meshing transmission between each planetary gear pair 3-1 or 3-2 and the sun gears on both sides is a "worm gear" mechanism. The overlapping meshing of the two planetary worm gears in each pair of planetary worm gear pairs is achieved by spur or helical cylindrical gears set on both sides of the same axis.

[0025] See Figure 1 — Figure 7 The double sun gear planetary differential shown has transmission gears with involute tooth profiles, or other conjugate profiles—such as circular or cycloid profiles—or degenerates into toothless profiles (i.e., toothless) and uses friction traction drive—with a loading mechanism; each planetary gear may not have a pivot and instead be directly supported by its tooth tip cylinder within the shaft hole of the planetary gear carrier for free rotation.

[0026] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of this utility model that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of this utility model and do not limit the scope of protection of this utility model patent.

Claims

1. A double-sun gear planetary gear train differential with meshing connections between pairs of planetary gears, comprising: a left or front sun gear and a right or rear sun gear coaxially arranged; a plurality of pairs of planetary gears overlapping and meshing on a portion of the width of the sun gears; on the remaining width of the total width, one planetary gear of each pair meshes with the left or front sun gear, while the other planetary gear meshes with the right or rear sun gear; each pair of planetary gears is freely rotatable by a pivot and within a bore of a planetary gear carrier, characterized in that... The planetary gear pairs of the planetary gear train differential are "mutually meshed".

2. The planetary gear train differential as described in claim 1, characterized in that... The transmission gear composed of the sun gear and planetary gears is a spur gear or a helical gear.

3. The planetary gear train differential as described in claim 1 or 2, characterized in that... The overlapping meshing of the two planetary gears in each planetary gear pair and the interconnection meshing between each pair of planetary gear pairs are located on the central portion of the width of each planetary gear, or on the width of its two sides.

4. The planetary gear train differential as described in claim 1 or 2, characterized in that... The two sun gears and their respective output connection structures can be circumferentially divided and then connected by a helical spline transmission mechanism. The helical splines on both sides have different directions of rotation, one to the left and one to the right, and are opposite to the helical direction of their respective meshing sun helical gears. The output connection structure includes an internal straight spline.

5. The planetary gear train differential as described in claim 1 or 2, characterized in that... Number of teeth on both sides of the sun gear z Sun different, z S(F(L)) < z S(R(R)) or z S(R(R)) < z S(F(L)) At this point, the rotation axes of the two planetary gears in each planetary gear pair are located on different distribution circles; where: z S(F(L)) The number of teeth on the front sun gear. z S(R(R)) This refers to the number of teeth on the rear sun gear.

6. The planetary gear train differential as described in claim 1 or 2, characterized in that... One of the sun gears on both sides that meshes externally with each pair of planetary gear pairs can be an internally meshing ring gear. In this case, the ring gear can also serve as the input shaft or input end of the differential, while the planetary gear carrier serves as an output shaft or output end.

7. The planetary gear train differential as described in claim 1 or 2, characterized in that... The tooth profile of the transmission gear is an involute tooth profile or a general conjugate tooth profile, wherein the conjugate tooth profile includes at least a circular arc tooth profile or a cycloidal tooth profile; or the tooth profile of the transmission gear can be omitted or is toothless, in which case the gear transmission is replaced by friction traction transmission.

8. The planetary gear train differential as described in claim 1 or 2, characterized in that... The meshing between each pair of planetary gears can also be disengaged by reducing the number of pairs, and each pair of planetary gears becomes independent of each other.

9. The planetary gear train differential as described in claim 8, characterized in that... Each planetary gear meshes with the sun gears on both sides for transmission or is a "worm gear-worm" mechanism. In this case, the overlapping meshing of the width of each pair of planetary worm gear pairs is achieved by spur or helical cylindrical gears set on both sides of the same axis.

10. The planetary gear train differential as described in claim 1 or 2, characterized in that... Each planetary gear is not pivoted but is directly supported by its tooth tip cylinder within the shaft hole of the planetary gear carrier and rotates freely.

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