A multi-gear mechanical automatic transmission and a working method thereof

Abstract

The application discloses a kind of multi-gear mechanical automatic transmission and its working method, belong to transmission technical field;Including the shaft and two axes that are sequentially arranged from input end to output end;The two sides of the shaft and two axes are also respectively provided with intermediate shaft;The part of the shaft and intermediate shaft is located in front auxiliary box;The part of the two axes and intermediate shaft is located in main box;The shaft is successively sleeved with shaft speed dividing gear and shaft gear;The two axes are successively sleeved with three gear, two gear, first gear and reverse gear;The intermediate shaft is successively provided with intermediate shaft speed dividing gear, intermediate shaft transmission gear, intermediate shaft three gear, intermediate shaft two gear, intermediate shaft first gear and intermediate shaft reverse gear, which are engaged with each gear on the shaft and two axes.The application cancels rear auxiliary box, reduces transmission gap, reduces the weight of transmission, facilitates vehicle arrangement and reduces fuel consumption.

Description

Technical Field

[0001] This invention belongs to the field of transmission technology and relates to a multi-speed mechanical automatic transmission and its working method. Background Technology

[0002] With the development and upgrading of the passenger transport industry, the market has placed more stringent demands on the overall performance of tourist buses and commercial passenger vehicles. While pursuing higher passenger comfort, fuel economy, operating efficiency, and total lifecycle cost have also become core indicators of concern for users. As a key assembly in the automotive powertrain system, the choice of transmission technology directly affects the vehicle's power, economy, and driving experience.

[0003] In the field of automatic transmissions for commercial vehicles, there are currently two main technical solutions: hydraulic automatic transmissions (AT) and automated manual transmissions (AMT). AT transmissions achieve automatic shifting through a torque converter and planetary gear mechanism, offering advantages such as smooth shifting and high driving comfort. However, their hydraulic transmission efficiency is relatively low, resulting in significantly higher fuel consumption than manual transmissions. This contradicts the current development trend of "cost reduction and efficiency improvement" and energy conservation and emission reduction in the transportation industry, limiting the widespread application of AT transmissions in medium and large-sized buses. In contrast, AMT transmissions are based on traditional manual transmissions with the addition of an automatic shift control system. Their core transmission components still consist of multiple pairs of high-precision gears, thus inheriting the advantages of manual transmissions such as high transmission efficiency, strong load-bearing capacity, good reliability, and low manufacturing cost. In recent years, with continuous advancements in electronic control technology, actuator precision, and shift strategy algorithms, the shifting quality of modern AMT transmissions has been greatly improved. Shift shocks and power interruption times have been significantly reduced, and comfort can now rival or even surpass some AT transmissions, making it one of the preferred technologies for commercial vehicle automation.

[0004] Currently, in passenger vehicle AMT transmissions, a "4×2" structure is commonly used to meet the demands of multiple gears (e.g., 8 gears) and high torque capacity. This structure combines a main gearbox and an auxiliary gearbox, with the auxiliary gearbox providing high-low gear switching, together creating eight or more forward gears. Due to the presence of the rear auxiliary gearbox, the entire transmission chain lengthens, and the accumulated clearances in various components such as gear meshing clearance, spline connection clearance, and bearing clearance result in a larger overall transmission clearance. Under specific operating conditions such as frequent vehicle starts, gear shifts, or drastic load changes, this larger clearance causes repeated knocking of gear teeth, generating significant noise and affecting the vehicle's NVH (noise, vibration, and harshness) performance and ride comfort. Furthermore, the addition of the rear auxiliary gearbox also necessitates a longer housing and more components, directly increasing the overall length and weight of the transmission. This hinders the compact layout of the vehicle chassis and increases the overall vehicle weight, negatively impacting fuel efficiency. When a parallel hydraulic retarder is needed to improve vehicle safety on long downhill slopes, the traditional "4×2" transmission often requires an additional connecting housing after the rear auxiliary gearbox, which further exacerbates the problems of transmission length and weight.

[0005] In summary, how to effectively eliminate the problems of large transmission clearance, high noise, and redundant structure caused by the rear auxiliary gearbox while maintaining the advantages of high efficiency and high reliability of AMT transmission, and how to optimize the matching and installation of the retarder, are technical challenges that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-speed mechanical automatic transmission and its working method to solve the technical problems in the prior art where the presence of the rear auxiliary gearbox of the transmission results in a long transmission chain, large cumulative clearance, which is not conducive to the overall vehicle layout and has high fuel consumption.

[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a multi-speed mechanical automatic transmission, comprising a first shaft and a second shaft arranged sequentially from the input end to the output end; an intermediate shaft is also provided on both sides of the first shaft and the second shaft; a portion of the first shaft and the intermediate shaft is located in the front auxiliary gearbox; a portion of the second shaft and the intermediate shaft is located in the main gearbox; a first shaft distribution gear and a first shaft gear are sequentially loosely fitted on the first shaft; a third gear, a second gear, a first gear and a reverse gear are sequentially loosely fitted on the second shaft; and an intermediate shaft distribution gear, an intermediate shaft transmission gear, an intermediate shaft third gear, an intermediate shaft second gear, an intermediate shaft first gear and an intermediate shaft reverse gear are sequentially arranged on the intermediate shaft, meshing with the gears on the first shaft and the second shaft.

[0008] Furthermore, a spline sleeve is provided at one end of the second shaft near the first shaft; the spline sleeve has an internal spline and an external spline; a third and fourth gear sliding sleeve is installed on the spline sleeve; the third and fourth gear sliding sleeve is connected to the first shaft gear through an internal spline, and the third and fourth gear sliding sleeve is connected to the third gear through an external spline.

[0009] Furthermore, the spline sleeve is axially fixed to the two shafts by a snap ring.

[0010] Furthermore, a reverse gear sliding sleeve is provided between the reverse gear and the first gear; a first and second gear sliding sleeve is provided between the first gear and the second gear.

[0011] Furthermore, the reverse gear and the intermediate shaft reverse gear are driven by a reverse gear intermediary.

[0012] Furthermore, a front and auxiliary gearbox synchronizer is provided between the first shaft speed-dividing gear and the first shaft gear.

[0013] Furthermore, a flange is installed at the end of the two shafts; a retarder driven gear and an odometer rotor are sequentially arranged between the reverse gear and the flange.

[0014] Furthermore, a brake is provided at one end of the intermediate shaft on one side of the two shafts; an oil pump drive interface is provided at one end of the intermediate shaft on the other side of the two shafts, and the brake and the oil pump drive interface are located near the intermediate shaft speed distribution gear.

[0015] Furthermore, the intermediate shaft is connected to the intermediate shaft speed-dividing gear, the intermediate shaft transmission gear, and the intermediate shaft third gear via connecting pins; the front auxiliary housing is equipped with an intermediate shaft speed sensor for monitoring the intermediate shaft speed; and the main housing is equipped with an output shaft speed sensor for monitoring the second shaft speed.

[0016] Secondly, the present invention provides a method for operating a multi-speed mechanical automatic transmission, comprising the following steps: When in first gear, the front auxiliary gearbox synchronizer engages with the first shaft speed distribution gear, and the first and second gear sliding sleeves engage with the first gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft speed distribution gear, the intermediate shaft speed distribution gear, the intermediate shaft, the intermediate shaft first gear, the first gear, and the first and second gear sliding sleeves to the second shaft. When in second gear, the front auxiliary gearbox synchronizer engages with the first shaft gear, and the first and second gear sliding sleeves engage with the first gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft gear, the intermediate shaft transmission gear, the intermediate shaft, the intermediate shaft first gear, the first gear, and the first and second gear sliding sleeves to the second shaft. When in 3rd gear, the front auxiliary gearbox synchronizer engages with the first shaft speed distribution gear, and the first and second gear sliding sleeves engage with the second gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft speed distribution gear, the intermediate shaft speed distribution gear, the intermediate shaft, the intermediate shaft second gear, the second gear, and the first and second gear sliding sleeves to the second shaft. When in 4th gear, the front auxiliary gearbox synchronizer engages with the first shaft gear, and the first and second gear sliding sleeves engage with the second gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft gear, the intermediate shaft transmission gear, the intermediate shaft, the intermediate shaft second gear, the second gear, and the first and second gear sliding sleeves to the second shaft. When in 5th gear, the front auxiliary gearbox synchronizer engages with the first shaft speed distribution gear, and the third and fourth gear sliding sleeves engage with the third gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft speed distribution gear, the intermediate shaft speed distribution gear, the intermediate shaft, the intermediate shaft third gear, the third gear, and the third and fourth gear sliding sleeves to the second shaft. When in 6th gear, the front auxiliary gearbox synchronizer engages with the first shaft gear, and the third and fourth gear sliding sleeves engage with the third gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft gear, the intermediate shaft transmission gear, the intermediate shaft, the intermediate shaft third gear, the third gear, and the third and fourth gear sliding sleeves to the second shaft. When in 7th gear, the front auxiliary gearbox synchronizer engages with the first shaft gear, and the third and fourth gear sleeves engage with the first shaft gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft gear, the intermediate shaft gear, the intermediate shaft, the intermediate shaft transmission gear, the first shaft gear, and the third and fourth gear sleeves to the second shaft. When in 8th gear, the front auxiliary gearbox synchronizer engages with the first shaft gear, and the third and fourth gear sliding sleeves engage with the first shaft gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft gear, and the third and fourth gear sliding sleeves to the second shaft. When reverse gear is engaged, the front auxiliary gearbox synchronizer engages with the first shaft's speed distribution gear, and the reverse gear sleeve engages with the reverse gear. Power is transmitted sequentially through the first shaft, the front auxiliary gearbox synchronizer, the first shaft's speed distribution gear, the intermediate shaft's speed distribution gear, the intermediate shaft, the intermediate shaft's reverse gear, the reverse gear interlocking wheel, the reverse gear, and the reverse gear sleeve to the second shaft.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a multi-speed mechanical automatic transmission and its operating method. By eliminating the rear auxiliary gearbox, all eight gears are integrated into the front auxiliary gearbox and main gearbox, fundamentally eliminating the problems of transmission chain growth and clearance accumulation caused by the rear auxiliary gearbox structure. This significantly reduces the clearance in gear meshing and spline connections, effectively avoiding gear knocking noise caused by excessive clearance under certain operating conditions, and significantly improving the transmission's NVH performance and the overall vehicle ride comfort. While matching a parallel retarder, the new structure can reduce a section of the rear cover housing, significantly shortening the overall axial length of the transmission, making the structure more compact, and greatly reducing weight. This not only benefits the space layout of the vehicle chassis and reduces the vehicle's weight, but also effectively contributes to weight reduction and fuel efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a simplified structural diagram of a multi-speed mechanical automatic transmission according to the present invention; Figure 2 This is a simplified diagram of the two-shaft, three- and four-speed sliding sleeve structure of a multi-speed mechanical automatic transmission according to the present invention.

[0020] Wherein: 1-Shaft 1; 2-Shaft 1 speed divider gear; 3-Front auxiliary gearbox synchronizer; 4-Shaft 1 gear; 5-Intermediate shaft speed divider gear; 6-Intermediate shaft; 7-Intermediate shaft transmission gear; 8-Intermediate shaft third gear; 9-Intermediate shaft second gear; 10-Intermediate shaft first gear; 11-Intermediate shaft reverse gear; 12-Reverse gear intermediate wheel; 13-Odometer rotor; 14-Flange; 15-Retarder driven gear; 16-Reverse gear; 17-Reverse gear sleeve; 18-First gear; 19-First and second gear sleeves; 20-Second gear; 21-Shaft 2; 22-Third gear; 23-Third and fourth gear sleeves; 24-Thrust bearing; 25-Brake; 26-Oil pump drive interface; 27-Connecting pin; 28-Intermediate shaft speed sensor; 29-Output shaft speed sensor; 30-Front auxiliary gearbox; 31-Main gearbox; 32-Snap ring; 33-Spline sleeve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1This invention discloses a multi-speed mechanical automatic transmission, including a primary shaft 1 and a secondary shaft 21 arranged sequentially from the input end to the output end; an intermediate shaft 6 is also arranged on both sides of the primary shaft 1 and the secondary shaft 21; a portion of the primary shaft 1 and the intermediate shaft 6 is located in the front auxiliary gearbox 30; a portion of the secondary shaft 21 and the intermediate shaft 6 is located in the main gearbox 31; a primary shaft distribution gear 2 and a primary shaft gear 4 are loosely fitted on the primary shaft 1 from left to right; a third gear 22, a second gear 20, a first gear 18, and a reverse gear 16 are loosely fitted on the secondary shaft 21; an intermediate shaft distribution gear 5, an intermediate shaft transmission gear 7, an intermediate shaft third gear 8, an intermediate shaft second gear 9, an intermediate shaft first gear 10, and an intermediate shaft reverse gear 11 are arranged sequentially from left to right on the intermediate shaft 6, meshing with the gears on the primary shaft 1 and the secondary shaft 21. Specifically, the first-shaft gear 2 is constantly meshed with the intermediate shaft gear 5, the first-shaft gear 4 is constantly meshed with the intermediate shaft transmission gear 7, the third-speed gear 22 is constantly meshed with the intermediate shaft third-speed gear 8, the second-speed gear 20 is constantly meshed with the intermediate shaft second-speed gear 9, the first-speed gear 18 is constantly meshed with the intermediate shaft first-speed gear 10, and the reverse gear 16 is driven by the reverse gear intermediate wheel 12 and the intermediate shaft reverse gear 11. This invention provides a multi-speed mechanical automatic transmission, employing a 2x4 front auxiliary gearbox and main gearbox structure, which can significantly reduce the transmission backlash of an 8-speed transmission and improve the shifting comfort of the entire transmission system. While matching a parallel retarder, the new structure can reduce a section of the rear cover housing, thereby shortening the length of the transmission, reducing its weight, facilitating vehicle layout, and reducing fuel consumption.

[0028] In one feasible embodiment of the present invention, see [link to relevant documentation]. Figure 2 A spline sleeve 33 is provided at one end of the second shaft 21 near the first shaft 1. The spline sleeve 33 has internal splines and external splines. A third and fourth gear sliding sleeve 23 is installed on the spline sleeve 33. The third and fourth gear sliding sleeve 23 is connected to the first shaft gear 4 via an internal spline, and the third and fourth gear sliding sleeve 23 is connected to the third gear 22 via an external spline. By using splines, the problem of not being able to install internal splines on the first shaft gear 4 is solved, and the structure of the third and fourth gear sliding sleeve 23 is also simplified. The spline sleeve 33 is axially fixed to the second shaft 21 by a snap ring 32.

[0029] In one feasible embodiment of the present invention, a reverse gear sleeve 17 is provided between the reverse gear 16 and the first gear 18; a first-second gear sleeve 19 is provided between the first gear 18 and the second gear 20. The reverse gear 16 and the intermediate shaft reverse gear 11 are driven by a reverse gear intermediate wheel 12. A front and auxiliary gearbox synchronizer 3 is provided between the first shaft speed distribution gear 2 and the first shaft gear 4 on the first shaft 1.

[0030] In one feasible embodiment of the present invention, a flange 14 is installed at the end of the second shaft 21; a retarder driven gear 15 and an odometer rotor 13 are sequentially arranged between the reverse gear 16 and the flange 14. A brake 25 is provided at one end of the intermediate shaft 6 on one side of the second shaft 21 for upshifting the transmission; an oil pump drive interface 26 is provided at one end of the intermediate shaft 6 on the other side of the second shaft 21 for driving the oil pump to provide lubrication for the transmission. The brake 25 and the oil pump drive interface 26 are located near the intermediate shaft's distribution gear 5. In this embodiment, the flange 14 is splined to the second shaft 21 for connecting to the vehicle's drive shaft. A support bearing is installed on the second shaft 21 after the reverse gear 16. Between the rear support bearing of the second shaft 21 and the flange 14, the retarder driven gear 15 and the odometer rotor 13 are installed. The retarder driven gear 15 is splined to the second shaft 21 and meshes with the retarder gear to decelerate the entire transmission system. The odometer rotor 13 is used for mileage counting.

[0031] In one feasible embodiment of the present invention, the intermediate shaft 6 is installed with the intermediate shaft speed-dividing gear 5, the intermediate shaft transmission gear 7 and the intermediate shaft third gear 8 respectively via connecting pins 27; the front auxiliary box 30 is provided with an intermediate shaft speed sensor 28 for monitoring the rotational speed of the intermediate shaft 6; the main box 31 is provided with an output shaft speed sensor 29 for monitoring the rotational speed of the second shaft 21.

[0032] This invention also discloses a method for operating a multi-speed mechanical automatic transmission, comprising the following steps: When in first gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft speed divider gear 2, and the first and second gear sliding sleeve 19 engages with the first gear 18. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft speed divider gear 2, the intermediate shaft speed divider gear 5, the intermediate shaft 6, the intermediate shaft first gear 10, the first gear 18, and the first and second gear sliding sleeve 19 to the second shaft 21. When in second gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft gear 4, and the first and second gear sliding sleeve 19 engages with the first gear 18. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft gear 4, the intermediate shaft transmission gear 7, the intermediate shaft 6, the intermediate shaft first gear 10, the first gear 18, and the first and second gear sliding sleeve 19 to the second shaft 21. When in 3rd gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft speed divider gear 2, and the first and second gear sliding sleeve 19 engages with the second gear 20. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft speed divider gear 2, the intermediate shaft speed divider gear 5, the intermediate shaft 6, the intermediate shaft second gear 9, the second gear 20, and the first and second gear sliding sleeve 19 to the second shaft 21. When in 4th gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft gear 4, and the first and second gear sliding sleeve 19 engages with the second gear 20. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft gear 4, the intermediate shaft transmission gear 7, the intermediate shaft 6, the intermediate shaft second gear 9, the second gear 20, and the first and second gear sliding sleeve 19 to the second shaft 21. When in 5th gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft speed distribution gear 2, and the third and fourth gear sliding sleeve 23 engages with the third gear 22. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft speed distribution gear 2, the intermediate shaft speed distribution gear 5, the intermediate shaft 6, the intermediate shaft third gear 8, the third gear 22, and the third and fourth gear sliding sleeve 23 to the second shaft 21. When in 6th gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft gear 4, and the third and fourth gear sliding sleeve 23 engages with the third gear 22. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft gear 4, the intermediate shaft transmission gear 7, the intermediate shaft 6, the intermediate shaft third gear 8, the third gear 22, and the third and fourth gear sliding sleeve 23 to the second shaft 21. When in 7th gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft speed distribution gear 2, and the third and fourth gear sliding sleeve 23 engages with the first shaft gear 4. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft speed distribution gear 2, the intermediate shaft speed distribution gear 5, the intermediate shaft 6, the intermediate shaft transmission gear 7, the first shaft gear 4, and the third and fourth gear sliding sleeve 23 to the second shaft 21. When in 8th gear, the front auxiliary gearbox synchronizer 3 engages with the first shaft gear 4, and the third and fourth gear sliding sleeve 23 engages with the first shaft gear 4. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft gear 4, and the third and fourth gear sliding sleeve 23 to the second shaft 21. When reverse gear is engaged, the front auxiliary gearbox synchronizer 3 engages with the first shaft speed distribution gear 2, and the reverse gear sleeve 17 engages with the reverse gear 16. Power is transmitted sequentially through the first shaft 1, the front auxiliary gearbox synchronizer 3, the first shaft speed distribution gear 2, the intermediate shaft speed distribution gear 5, the intermediate shaft 6, the intermediate shaft reverse gear 11, the reverse gear interlocking wheel 12, the reverse gear 16, and the reverse gear sleeve 17 to the second shaft 21.

[0033] The working principle of this invention is as follows: This invention relates to a multi-speed mechanical automatic transmission, comprising a primary shaft 1 and a secondary shaft 21 arranged sequentially from the input end to the output end; a primary shaft 1 is loosely fitted with a primary shaft distribution gear 2 and a primary shaft gear 4; the secondary shaft is loosely fitted with a third gear 22, a second gear 20, a first gear 18, and a reverse gear 16; a retarder driven gear 15 is fixed to the end of the secondary shaft via a spline. This invention adopts a 2x4 structure and is a new two-stage 8-speed transmission with a front auxiliary gearbox, a main gearbox, and two intermediate shafts with helical gears, having two intermediate shafts 6 on the left and right sides.

[0034] The power transmission route of this invention is as follows: the engine power is transmitted to the first shaft 1 of the transmission via the clutch. The front auxiliary gearbox synchronizer 3 on the first shaft 1 engages with the first shaft gear 2 or the first shaft gear 4 on the first shaft 1, thereby enabling the gears on the first shaft to mesh with the intermediate shaft gear 5 or the intermediate shaft transmission gear 7, thus driving the intermediate shaft 6 and its gears. At this time, the other gear on the first shaft 1 idles on the first shaft 1. The gears on the intermediate shaft 6 are constantly meshed with the gears on the second shaft 21, so the gears on the second shaft 21 rotate simultaneously. The gears on the second shaft 21 are loosely fitted on the second shaft 21, so the second shaft 21 does not rotate when in neutral (i.e., the reverse gear sleeve 17, the first and second gear sleeves 19, and the third and fourth gear sleeves 23 on the second shaft 21 are in the middle position). When the reverse gear sleeve 17, first and second gear sleeves 19, and third and fourth gear sleeves 23 on the second shaft move to a certain gear position and connect the second shaft gear with the second shaft 21 as one unit, the second shaft 21 begins to rotate, and the power is output to the flange 14.

[0035] Specifically, for each gear, the power transmission route is as follows: 1st gear: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 speed divider gear 2 → Intermediate shaft speed divider gear 5 → Intermediate shaft 6 → Intermediate shaft first gear 10 → First gear 18 → First and second gear sliding sleeve 19 → Second shaft 21 → Flange 14; 2 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 4 → Intermediate shaft transmission gear 7 → Intermediate shaft 6 → Intermediate shaft first gear 10 → First gear 18 → First and second gear sliding sleeve 19 → Second shaft 21 → Flange 14; 3 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 2 → Intermediate shaft gear 5 → Intermediate shaft 6 → Intermediate shaft second gear 9 → Second gear 20 → First and second gear sliding sleeve 19 → Second shaft 21 → Flange 14; 4 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 4 → Intermediate shaft transmission gear 7 → Intermediate shaft 6 → Intermediate shaft second gear 9 → Second gear 20 → First and second gear sliding sleeve 19 → Second shaft 21 → Flange 14; 5 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 2 → Intermediate shaft gear 5 → Intermediate shaft 6 → Intermediate shaft third gear 8 → Third gear 22 → Third and fourth gear sliding sleeve 23 → Shaft 21 → Flange 14; 6 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 4 → Intermediate shaft transmission gear 7 → Intermediate shaft 6 → Intermediate shaft third gear 8 → Third gear 22 → Third and fourth gear sliding sleeve 23 → Shaft 21 → Flange 14; 7 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 2 → Intermediate shaft gear 5 → Intermediate shaft 6 → Intermediate shaft transmission gear 7 → Shaft 1 gear 4 → Third and fourth gear sliding sleeve 23 → Second shaft 21 → Flange 14; 8 gears: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 gear 4 → Third and fourth gear sliding sleeve 23 → Shaft 21 → Flange 14; Reverse gear: Shaft 1 → Front auxiliary gearbox synchronizer 3 → Shaft 1 speed distribution gear 2 → Intermediate shaft speed distribution gear 5 → Intermediate shaft 6 → Intermediate shaft reverse gear 11 → Reverse gear intermediate wheel 12 → Reverse gear 16 → Reverse gear sliding sleeve 17 → Shaft 21 → Flange 14.

[0036] The above describes the power transmission route for a direct-drive transmission. For overdrive transmissions, simply reverse the odd and even positions to refer to the direct-drive transmission route.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-speed mechanical automatic transmission, characterized in that, It includes a first shaft (1) and a second shaft (21) arranged sequentially from the input end to the output end; an intermediate shaft (6) is also arranged on both sides of the first shaft (1) and the second shaft (21); parts of the first shaft (1) and the intermediate shaft (6) are located in the front auxiliary box (30); parts of the second shaft (21) and the intermediate shaft (6) are located in the main box (31); a first shaft gear (2) and a first shaft gear (4) are sequentially fitted on the first shaft (1); a third gear (22), a second gear (20), a first gear (18) and a reverse gear (16) are sequentially fitted on the second shaft (21); an intermediate shaft gear (5), an intermediate shaft transmission gear (7), an intermediate shaft third gear (8), an intermediate shaft second gear (9), an intermediate shaft first gear (10) and an intermediate shaft reverse gear (11) are sequentially arranged on the intermediate shaft (6) to mesh with the gears on the first shaft (1) and the second shaft (21).

2. The multi-speed mechanical automatic transmission according to claim 1, characterized in that, A spline sleeve (33) is provided at one end of the second shaft (21) near the first shaft (1); the spline sleeve (33) has an inner spline and an outer spline; a third and fourth gear sliding sleeve (23) is installed on the spline sleeve (33); the third and fourth gear sliding sleeve (23) is connected to the first shaft gear (4) through an inner spline, and the third and fourth gear sliding sleeve (23) is connected to the third gear (22) through an outer spline.

3. A multi-speed mechanical automatic transmission according to claim 2, characterized in that, The spline sleeve (33) is axially fixed to the second shaft (21) by a snap ring (32).

4. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, A reverse gear sleeve (17) is provided between the reverse gear (16) and the first gear (18); a first and second gear sleeve (19) is provided between the first gear (18) and the second gear (20).

5. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, The reverse gear (16) and the intermediate shaft reverse gear (11) are driven by the reverse gear intermediate wheel (12).

6. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, A front and auxiliary gearbox synchronizer (3) is provided between the first shaft speed distribution gear (2) and the first shaft gear (4) on the first shaft (1).

7. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, A flange (14) is installed at the end of the two shafts (21); a retarder driven gear (15) and an odometer rotor (13) are arranged sequentially between the reverse gear (16) and the flange (14).

8. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, A brake (25) is provided at one end of the intermediate shaft (6) on one side of the two shafts (21); an oil pump drive interface (26) is provided at one end of the intermediate shaft (6) on the other side of the two shafts (21). The brake (25) and the oil pump drive interface (26) are located near the intermediate shaft speed divider gear (5).

9. A multi-speed mechanical automatic transmission according to claim 1, characterized in that, The intermediate shaft (6) is connected to the intermediate shaft speed distribution gear (5), the intermediate shaft transmission gear (7) and the intermediate shaft three-speed gear (8) respectively by connecting pins (27); the front auxiliary box (30) is provided with an intermediate shaft speed sensor (28) for monitoring the speed of the intermediate shaft (6); the main box (31) is provided with an output shaft speed sensor (29) for monitoring the speed of the second shaft (21).

10. A method for operating an 8-speed mechanical automatic transmission according to any one of claims 1 to 9, characterized in that, Includes the following steps: When in first gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft speed divider gear (2), and the first and second gear sliding sleeve (19) engages with the first gear (18). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft speed divider gear (2), the intermediate shaft speed divider gear (5), the intermediate shaft (6), the intermediate shaft first gear (10), the first gear (18), and the first and second gear sliding sleeve (19) to the second shaft (21). When in 2nd gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft gear (4), and the first and second gear sliding sleeve (19) engages with the first gear gear (18). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft gear (4), the intermediate shaft transmission gear (7), the intermediate shaft (6), the intermediate shaft first gear gear (10), the first gear gear (18), and the first and second gear sliding sleeve (19) to the second shaft (21). When in 3rd gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft speed distribution gear (2), and the first and second gear sliding sleeve (19) engages with the second gear (20). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft speed distribution gear (2), the intermediate shaft speed distribution gear (5), the intermediate shaft (6), the intermediate shaft second gear (9), the second gear (20), and the first and second gear sliding sleeve (19) to the second shaft (21). When in 4th gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft gear (4), and the first and second gear sliding sleeve (19) engages with the second gear (20). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft gear (4), the intermediate shaft transmission gear (7), the intermediate shaft (6), the intermediate shaft second gear (9), the second gear (20), and the first and second gear sliding sleeve (19) to the second shaft (21). When in 5th gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft speed distribution gear (2), and the third and fourth gear sliding sleeve (23) engages with the third gear (22). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft speed distribution gear (2), the intermediate shaft speed distribution gear (5), the intermediate shaft (6), the intermediate shaft third gear (8), the third gear (22), and the third and fourth gear sliding sleeve (23) to the second shaft (21). When in 6th gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft gear (4), and the third and fourth gear sliding sleeve (23) engages with the third gear (22). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft gear (4), the intermediate shaft transmission gear (7), the intermediate shaft (6), the intermediate shaft third gear (8), the third gear (22), and the third and fourth gear sliding sleeve (23) to the second shaft (21). When in 7th gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft speed distribution gear (2), and the third and fourth gear sliding sleeve (23) engages with the first shaft gear (4). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft speed distribution gear (2), the intermediate shaft speed distribution gear (5), the intermediate shaft (6), the intermediate shaft transmission gear (7), the first shaft gear (4), and the third and fourth gear sliding sleeve (23) to the second shaft (21). When in 8th gear, the front auxiliary gearbox synchronizer (3) engages with the first shaft gear (4), and the third and fourth gear sliding sleeve (23) engages with the first shaft gear (4). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft gear (4), and the third and fourth gear sliding sleeve (23) to the second shaft (21). When reverse gear is engaged, the front auxiliary gearbox synchronizer (3) engages with the first shaft speed distribution gear (2), and the reverse gear sleeve (17) engages with the reverse gear (16). Power is transmitted sequentially through the first shaft (1), the front auxiliary gearbox synchronizer (3), the first shaft speed distribution gear (2), the intermediate shaft speed distribution gear (5), the intermediate shaft (6), the intermediate shaft reverse gear (11), the reverse gear interlocking wheel (12), the reverse gear (16), and the reverse gear sleeve (17) to the second shaft (21).

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