A 14-speed mechanical automatic transmission

Abstract

The application discloses a 14-gear mechanical automatic transmission, which comprises a transmission shell, a front auxiliary gearbox, a main gearbox and a rear auxiliary gearbox which are sequentially communicated from front to back are arranged in the transmission shell; an axle is arranged in the front auxiliary gearbox, a second axle is arranged in the main gearbox, and a planetary wheel output shaft is arranged in the rear auxiliary gearbox; the axle, the second axle and the planetary wheel output shaft are coaxially connected; a left intermediate shaft and a right intermediate shaft are further arranged in the main gearbox; the transmission is of a three-section structure, 14 gears are arranged through cooperation, the front auxiliary gearbox has two gears, gear switching is realized through cooperation of a synchronizer; the axle and the second axle are connected into a whole, and the axle end is designed to be thinned, so that accidental gear shifting caused by mutual jumping of the axle and the second axle during vehicle running is reduced, accidental gear shifting caused by shaking is reduced, and the reliability of the transmission is improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology and relates to a transmission system, specifically a 14-speed mechanical automatic transmission. Background Technology

[0002] With the continuous development of the commercial vehicle market, the performance requirements for transmissions are also increasing. In the heavy-duty commercial vehicle sector, engine horsepower is increasing, and commercial vehicle transmissions will develop towards higher torque, larger speed ratios, longer lifespan, more gears, and higher reliability. Especially under heavy load and complex operating conditions, transmissions with high torque and a wide speed ratio range are being developed to meet the power needs of commercial vehicles under heavy load starting, acceleration, and climbing conditions.

[0003] Currently, most commercial vehicle transmissions on the market cannot simultaneously meet the demands of heavy-load starting and high-speed driving. The axial forces between the first and second shafts are balanced by thrust bearings. When the transmission is dragged in reverse, the axial forces of the first and second shafts are opposite, and the axial force of the transmission acts directly on the bearings, affecting their service life. At the same time, because the first and second shafts are disconnected, they have greater flexibility and tend to bounce, which can easily cause some gears to disengage during operation. The intermediate shaft assembly structure mostly uses heat-fitting, interference fit, and cylindrical pin fit to connect the gears on the intermediate shaft to transmit torque. However, when the transmitted torque is too large, the gears on the intermediate shaft are prone to relative rotation in the circumferential direction of the intermediate shaft, causing varying degrees of misalignment, sometimes even down to the millimeter level. This can lead to breakage or fracture of the cylindrical pins, making it difficult to guarantee the positional accuracy of the gears on the intermediate shaft. In addition, the existing dual intermediate shaft structure of the rear auxiliary gearbox is prone to pitting of the gears in the low gear range and damage to the synchronizer when the torque is high, which limits the performance of the transmission and urgently needs improvement. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a 14-speed mechanical automatic transmission to solve the technical problem that the transmissions in the existing technology cannot meet the needs of high horsepower heavy load start, low speed vehicle maneuvering and high speed driving.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A 14-speed mechanical automatic transmission includes a transmission housing. Within the transmission housing are a front auxiliary gearbox, a main gearbox, and a rear auxiliary gearbox, connected sequentially from front to back. The front auxiliary gearbox contains a first shaft, the main gearbox contains a second shaft, and the rear auxiliary gearbox contains a planetary gear output shaft. The first shaft, the second shaft, and the planetary gear output shaft are coaxially connected. The main gearbox also contains a left intermediate shaft and a right intermediate shaft, symmetrically arranged on either side of the second shaft. A first reverse gear intermediate shaft is located on the left rear end of the left intermediate shaft, and a second reverse gear intermediate shaft is located on the right rear end of the right intermediate shaft. The shaft is fitted with a speed measuring gear, a middle speed-dividing gear, a front auxiliary gearbox synchronizer, and a shaft transmission gear in sequence from front to back. The two shafts are fitted with a first sliding sleeve, a second gear, a first gear, a second sliding sleeve, a climbing gear, a reverse sliding sleeve, and a reverse gear in sequence from front to back. The left and right intermediate shafts are each provided with, from front to back, intermediate shaft speed distribution gear, intermediate shaft transmission gear, intermediate shaft second gear, intermediate shaft first gear, intermediate shaft creeping gear and intermediate shaft reverse gear; The first and second reverse gear intermediate shafts are each fitted with a reverse gear intermediate wheel that can mesh with the reverse gear of the intermediate shaft; The planetary gear output shaft is arranged from front to back as follows: rear auxiliary box planetary gear assembly, retarder driven gear, output shaft speed measuring rotor, and odometer rotor.

[0007] The present invention also includes the following technical features: Specifically, the two axes have an open end face at one end facing the first axis; The shaft includes a first connecting segment, a second connecting segment, and a third connecting segment that are integrally connected from front to back; The second connecting section is fitted with a first thrust bearing, which meshes with a shaft transmission gear; the third connecting section extends into the inner cavity; the third connecting section is fitted with a two-shaft connecting sleeve, a second thrust bearing, a limiting spacer, and a limiting lock plate in sequence from front to back; the two-shaft connecting sleeve includes a connecting sleeve body, the front end of the connecting sleeve body protrudes outward to form a protrusion, the protrusion is connected to the first thrust bearing and the two shafts respectively, and the connecting sleeve body is connected to the two shafts; the limiting spacer is connected to the third connecting section.

[0008] Furthermore, a first limiting step surface is formed at the connection between the first connecting segment and the second connecting segment, and a second limiting step surface is formed at the connection between the second connecting segment and the third connecting segment; the front end face of the first thrust bearing is in contact with the first limiting step surface, and the rear end face of the first thrust bearing abuts against the front end face of the protrusion; the front end face of the connecting sleeve body abuts against the second limiting step surface, and the rear end face of the connecting sleeve body abuts against the front end face of the second thrust bearing; The connecting sleeve body has a first retaining ring groove along the circumferential direction, and the inner wall of the inner cavity has a second retaining ring groove. The first retaining ring groove and the second retaining ring groove correspond to each other, and a retaining ring is sleeved in the first retaining ring groove. The third connecting section has a first limiting groove along its circumferential direction, and the limiting spacer is fitted inside the first limiting groove.

[0009] Furthermore, the outer wall of the two shafts is provided with keyways that extend axially at circumferential intervals. The keyways include a first keyway and a second keyway that are connected together, and a third limiting step is formed at the connection between the first keyway and the second keyway.

[0010] Furthermore, the rear auxiliary box planetary gear assembly includes a planetary gear mechanism and a synchronizer mechanism; The planetary gear mechanism includes a planet carrier mounted on the planetary gear output shaft, a planetary gear unit mounted on the planet carrier, a planetary gear ring meshing with the planetary gear unit and slidable along the axial direction of the planetary gear unit, a gear ring connecting sleeve meshing with the planetary gear ring, and a sun gear meshing with the planetary gear unit. The sun gear is also coaxially connected to the two shafts. The synchronizer mechanism includes a synchronizer sleeve, a high-gear gear ring, and a low-gear gear ring; the synchronizer sleeve is connected to the gear ring connecting sleeve; the high-gear gear ring is located at the axial front end of the planetary gear unit and is connected to the planet carrier; the low-gear gear ring is located at the axial front end of the high-gear gear ring and is connected to the inner wall of the transmission housing via a central connecting plate. When in high gear, the synchronizer sleeve moves axially backward and engages with the high gear gear ring for transmission; When in low gear, the synchronizer sleeve moves forward axially and engages with the low gear ring for transmission.

[0011] Furthermore, the planetary gear output shaft is connected to the second shaft via a spline sleeve. The front end of the planetary gear output shaft and the rear end of the second shaft both extend into the spline sleeve and are respectively connected to a limiting snap ring arranged axially in the spline sleeve.

[0012] Furthermore, a clutch actuator is also fitted at the front end of the shaft, and the clutch actuator is located in front of the speed measuring gear.

[0013] Furthermore, a lubricating oil pump is installed at the front end of the right intermediate shaft.

[0014] Furthermore, a brake is installed at the front end of the left intermediate shaft.

[0015] Compared with the prior art, the present invention has the following technical effects: (1) The transmission of the present invention adopts a three-section structure. Through the cooperation of the transmission, 14 gear positions are set. The front auxiliary gearbox has 2 gear positions. Through the cooperation of the synchronizer, the gear switching is realized.

[0016] (2) The present invention, through the design of the connection structure of the first shaft and the second shaft, makes the first shaft and the second shaft into a whole, which reduces the occasional disengagement caused by the mutual jumping of the first shaft and the second shaft during vehicle operation. At the same time, it avoids the opposite axial forces of the first shaft and the second shaft when the transmission is dragged. The axial force generated by the meshing of the helical gear inside the transmission directly acts on the bearings at both ends of each shaft, which improves the bearing and transmission life. The thinning tooth structure at the end of the second shaft further reduces the occasional disengagement caused by the vibration of the first shaft and the second shaft, and improves the reliability of the transmission.

[0017] (3) The present invention designs a planetary gear rear auxiliary box assembly structure that can withstand large torque. The load is evenly distributed by the floating of the planetary gear ring, and the load-bearing capacity is stronger. A large-diameter synchronizer is designed so that the gear shift of the rear auxiliary box is fast. At the same time, compared with the existing double intermediate shaft rear auxiliary box, the present invention has a compact structure, short axial dimension, and simple installation structure, which greatly shortens the installation length of the box. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0019] Figure 2 This is a partial structural schematic diagram I of the present invention; Figure 3 This is a schematic diagram of the biaxial keyway of the present invention; Figure 4 This is a partial structural schematic diagram II of the present invention.

[0020] The meanings of the labels in the diagram are as follows: 1-Transmission housing; 2-First shaft; 3-Second shaft; 4-Planetary gear output shaft; 5-Left intermediate shaft; 6-Right intermediate shaft; 7-First reverse gear intermediate shaft; 8-Second reverse gear intermediate shaft; 9-Speed ​​measuring gear; 10-First shaft intermediate gearbox gearbox; 11-Front auxiliary gearbox synchronizer; 12-First shaft drive gear; 13-First sliding sleeve; 14-Second shaft second gear; 15-Second shaft first gear; 16-Second sliding sleeve; 17-Second shaft creep gear; 18-Reverse gear sliding sleeve; 19-Second shaft reverse gear; 20-Intermediate shaft gearbox; 21-Intermediate shaft drive gear. 22-Second gear of intermediate shaft, 23-First gear of intermediate shaft, 24-Climbing gear of intermediate shaft, 25-Reverse gear of intermediate shaft, 26-Reverse gear intermediate wheel, 27-Planetary gear assembly of rear auxiliary gearbox, 28-Retarder driven gear, 29-Speed ​​measuring rotor of output shaft, 30-Odometer rotor, 31-First thrust bearing, 32-Connecting sleeve of first and second shafts, 33-Second thrust bearing, 34-Limiting spacer, 35-Limiting locking plate, 36-Snap ring, 37-Spline sleeve, 38-Limiting snap ring, 39-Clutch actuator, 40-Lubricating oil pump, 41-Brake; 101-Front auxiliary box, 102-Main box, 103-Rear auxiliary box; 201 - First connecting segment, 202 - Second connecting segment, 203 - Third connecting segment; 301-Keyway; 271-Planetary gear mechanism, 272-Synchronizer mechanism, 273-Center plate; 2711-Planet carrier, 2712-Planet gear unit, 2713-Planet gear ring, 2714-Gear ring connecting sleeve, 2715-Sun gear; 2721 - Synchronizer sleeve, 2722 - High-gear gear ring, 2723 - Low-gear gear ring; 321 - Connecting sleeve body; 322 - Protrusion; 3011 - First keyway, 3012 - Second keyway.

[0021] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0022] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0023] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "left," and "right" are generally defined based on the drawing in the corresponding figure; "inner" and "outer" refer to the inner and outer contours of the corresponding component; and "longitudinal," "transverse," and "vertical" refer to the directions marked in the figure.

[0024] Example: This embodiment provides a 14-speed mechanical automatic transmission, such as... Figures 1 to 3 As shown, the transmission includes a transmission housing 1, which adopts a 2X (3X2+1) three-section structure. The transmission housing 1 is provided with a front auxiliary gearbox 101, a main gearbox 102, and a rear auxiliary gearbox 103 connected from front to back. The front auxiliary gearbox 101 is provided with a first shaft 2, the main gearbox 102 is provided with a second shaft 3, and the rear auxiliary gearbox 103 is provided with a planetary gear output shaft 4. The first shaft 2, the second shaft 3, and the planetary gear output shaft 4 are arranged coaxially. The main gearbox 102 is also provided with a left intermediate shaft 5 and a right intermediate shaft 6. The left intermediate shaft 5 and the right intermediate shaft 6 are symmetrically arranged on both sides of the second shaft 3. The left side of the rear end of the left intermediate shaft 5 is provided with a first reverse gear intermediate shaft 7, and the right side of the rear end of the right intermediate shaft 6 is provided with a second reverse gear intermediate shaft 8. A speed measuring gear 9, a first-shaft intermediate speed-dividing gear 10, a front auxiliary box synchronizer 11, and a first-shaft transmission gear 12 are sequentially fitted on shaft 2 from front to back. The second shaft 3 is fitted with the first sliding sleeve 13, the second gear 14, the first gear 15, the second sliding sleeve 16, the climbing gear 17, the reverse sliding sleeve 18, and the reverse gear 19 in sequence from front to back. The left intermediate shaft 5 and the right intermediate shaft 6 are each provided with an intermediate shaft speed distribution gear 20, an intermediate shaft drive gear 21, an intermediate shaft second gear 22, an intermediate shaft first gear 23, an intermediate shaft creep gear 24, and an intermediate shaft reverse gear 25, arranged sequentially from front to back. Among them, the intermediate shaft second gear 22, intermediate shaft first gear 23, intermediate speed distribution gear 20, and intermediate shaft drive gear 21 can be fixed to the intermediate shaft by means of heat fitting, interference fit, and cylindrical pin.

[0025] Both the first reverse gear intermediate shaft 7 and the second reverse gear intermediate shaft 8 are fitted with reverse gear intermediate wheels 26 that can mesh with the reverse gear 25 of the intermediate shaft; The planetary gear output shaft 4 is arranged from front to back with the rear auxiliary gearbox planetary gear assembly 27, the retarder driven gear 28, the output shaft speed measuring rotor 29, and the odometer rotor 30. The retarder driven gear 28 is directly mounted on the planetary carrier, which simplifies the installation structure and greatly shortens the installation length of the gearbox.

[0026] In a preferred embodiment, the second shaft 3 has an open-end cavity at one end facing the first shaft 2; the first shaft 2 includes a first connecting section 201, a second connecting section 202, and a third connecting section 203 integrally connected from front to back; a first thrust bearing 31 is sleeved on the second connecting section 202, and the first thrust bearing 31 meshes with the first shaft transmission gear 12; the third connecting section 203 extends into the inner cavity; a first-second shaft connecting sleeve 32, a second thrust bearing 33, a limiting spacer 34, and a limiting locking piece 35 are sequentially sleeved on the third connecting section 203 from front to back; the first-second shaft connecting sleeve 32 includes a connecting sleeve body 321, the front end of the connecting sleeve body 321 protrudes outward to form a protrusion 322, the protrusion 322 is connected to the first thrust bearing 31 and the second shaft 3 respectively, and the connecting sleeve body 321 is connected to the second shaft 3; the limiting spacer 34 is connected to the third connecting section 203.

[0027] Through this structural design, shaft 2 and shaft 3 become a single unit, reducing occasional gear slippage caused by the mutual movement of shafts 2 and 3 during vehicle operation. Simultaneously, during normal vehicle operation, the axial force generated by the helical gear meshing results in a rearward axial force on shaft 2 and a forward axial force on shaft 3. These axial forces interact on the first thrust bearing 31. By adjusting the gear parameters of shafts 2 and 3, the axial forces can be balanced, preventing the bearings at both ends of each shaft from bearing the axial force generated by the high-torque transmission. When the vehicle descends a long, steep slope and the transmission is dragging backward, the axial forces on shafts 2 and 3 are opposite: the axial force on shaft 2 is forward, and the axial force on shaft 3 is rearward. Shafts 2 and 3 are connected as a single unit via the shaft connecting sleeve 32 and the retaining ring. The axial forces of shafts 2 and 3 interact on the second thrust bearing 33, balancing the axial forces, protecting the transmission bearings, extending the transmission's service life, and improving transmission reliability.

[0028] In a preferred embodiment, a first limiting step surface is formed at the connection between the first connecting segment 201 and the second connecting segment 202, and a second limiting step surface is formed at the connection between the second connecting segment 202 and the third connecting segment 203; the front end face of the first thrust bearing 31 is grounded with the first limiting step surface, and the rear end face of the first thrust bearing 31 abuts against the front end face of the protrusion 322; the front end face of the connecting sleeve body 321 abuts against the second limiting step surface, and the rear end face of the connecting sleeve body 321 abuts against the front end face of the second thrust bearing 33; a first retaining ring groove is provided on the circumferential direction of the connecting sleeve body 321, and a second retaining ring groove is provided on the inner wall of the inner cavity, the first retaining ring groove and the second retaining ring groove are corresponding, and a retaining ring 36 is sleeved in the first retaining ring groove; a first limiting groove is provided on the circumferential direction of the third connecting segment 203, and a limiting spacer 34 is sleeved in the first limiting groove.

[0029] As a preferred embodiment, the outer wall of the two shafts 3 is provided with keyways 301 extending axially at intervals along the circumferential direction. The keyways 301 include a first keyway 3011 and a second keyway 3012 that are connected together. A third limiting step is formed at the connection between the first keyway 3011 and the second keyway 3012.

[0030] As a preferred embodiment, the rear auxiliary box planetary gear assembly 27 includes a planetary gear mechanism 271 and a synchronizer mechanism 272; Specifically, the planetary gear mechanism 271 includes a planet carrier 2711 mounted on the planetary gear output shaft 4, a planetary gear unit 2712 mounted on the planet carrier 2711, a planetary gear ring 2713 that meshes with the planetary gear unit 2712 and can slide along the axial direction of the planetary gear unit 2712, a gear ring connecting sleeve 2714 that can mesh with the planetary gear ring 2713, and a sun gear 2715 that can mesh with the planetary gear unit 2712. The sun gear 2715 is also coaxially connected to the second shaft 3. The central connecting plate 273 is fixed to the transmission housing 1 by a cylindrical pin. The synchronizer mechanism 272 includes a synchronizer sleeve 2721, a high-gear ring gear 2722, and a low-gear ring gear 2723; the synchronizer sleeve 2721 is connected to the ring gear connecting sleeve 2714; the high-gear ring gear 2722 is located at the axial front end of the planetary gear unit 2712 and is connected to the planetary carrier 2711; the low-gear ring gear 2723 is located at the axial front end of the high-gear ring gear 2722 and is connected to the inner wall of the transmission housing 1 via the central connecting plate 273. In this preferred embodiment, the low-gear ring 2723 is fixedly connected to the central connecting plate 273 via a spline, and the high-gear ring 2722 is fixedly connected to the planetary carrier 2711 via a spline and is axially positioned by a retaining ring. The planetary ring 2713 adopts a floating design, and the outer ring of the ring connecting sleeve 2714 is connected to the planetary ring 2713 via an external spline. It is axially positioned by a retaining ring and a spline boss machined on the planetary ring 2713. The inner ring of the ring connecting sleeve 2714 is machined with an internal spline, which can cooperate with the synchronizer sleeve 2721. When in the high gear, the synchronizer sleeve 2721 moves axially backward and meshes with the high-gear ring 2722 for transmission. Specifically, the gear ring connecting sleeve 2714, planetary gear ring 2713, low gear gear ring 2723, synchronizer sliding sleeve 2721 and planet carrier 2711 rotate together. The sun gear 2715 in the planetary gear mechanism rotates as the power input element, and transmits the power to the planet gear output shaft 4 through the planet carrier 2711 and then outputs it through the flange. The rear speed ratio is 1. When in low gear, the synchronizer sleeve 2721 moves forward axially and engages with the low gear ring 2723 for transmission.

[0031] Specifically, the planetary gear ring 2713, the gear ring connecting sleeve 2714, the synchronizer sliding sleeve 2721, the low gear ring 2723 and the central connecting plate 273 are fixed together and cannot rotate. The power is input from the sun gear 2715 and transmitted to the planetary gear output shaft 4 through the planetary gear unit 2712, the planetary gear ring 2713 and the planet carrier 2711.

[0032] In a preferred embodiment, the front end of the sun gear 2715 is connected to the second shaft 3 via a spline sleeve 37. Both the front end of the sun gear 2715 and the rear end of the second shaft 3 extend into the spline sleeve 37 and are respectively connected to the limiting snap rings 38 arranged axially within the spline sleeve 37. The connection between the sun gear 2715 and the second shaft 3 via the spline sleeve 37 ensures that power is transmitted from the second shaft 3 to the rear auxiliary gearbox. The limiting snap rings 28 installed inside the spline sleeve 37 are used to separate the sun gear 2715 and the second shaft 3 in the planetary gear unit, providing axial limiting for the second shaft and the sun gear to each other. The structure is simple and compact.

[0033] In a preferred embodiment, a clutch actuator 39 is further sleeved at the front end of the shaft 2, and the clutch actuator 39 is located in front of the speed measuring gear 9. The clutch actuator 39 is a known prior art device capable of controlling the clutch actuator, brake, gear selection, and shifting actions of the transmission, thereby realizing the automatic shifting function of the automatic transmission.

[0034] As a preferred embodiment, a lubricating oil pump 40 is installed at the front end of the right intermediate shaft 6.

[0035] As a preferred embodiment, a brake 41 is installed at the front end of the left intermediate shaft 5.

[0036] In this embodiment, both the front and rear auxiliary gearboxes are shifted via synchronizers, while the main gearbox uses a sliding sleeve for gear engagement. The sliding sleeve has a longer lifespan and lower cost, but it does not have a synchronizing effect. An external spline drive brake 41 is designed at the front end of the left intermediate shaft. When the transmission shifts up, the brake 41 works to reduce the speed of the intermediate shaft through braking, thereby performing the upshift operation.

[0037] Taking the super climbing gear (first climbing gear) as an example, the power transmission route of this embodiment is explained as follows: When the transmission is engaged in super ramp gear, the upper front auxiliary gearbox synchronizer 11 on the first shaft 2 moves backward and engages with the first shaft drive gear 12. The second sliding sleeve 16 on the second shaft 3 slides backward, and the external spline on the second sliding sleeve 16 engages with the internal spline on the engagement gear ring of the second shaft ramp gear 17. Power is input from the first shaft 2, and through the front auxiliary gearbox synchronizer 11 and the first shaft drive gear 12, the power is split and transmitted to the intermediate shaft drive gear 21, and then the power is transmitted to the left intermediate shaft 5 and the right intermediate shaft 5. The intermediate shaft 6 drives the left intermediate shaft 5 and the right intermediate shaft 6 to rotate. The intermediate shaft creep gear 24 also rotates with the intermediate shaft. The power is transmitted to the second shaft creep gear 17 through the intermediate shaft creep gear 24. The second shaft creep gear 17 meshes with the outer spline of the second sliding sleeve 16 through the inner spline of the gear ring, and transmits the power to the second sliding sleeve 16. The second sliding sleeve 16 is connected to the second shaft 3 through the spline, thus transmitting the power from the first shaft 2 to the second shaft 3. The main gearbox part completes the gear shift.

[0038] Since the crawler gear is in the low gear range, the rear auxiliary gearbox is also in the low gear range. At this time, the TCU controls the movement of the rear auxiliary gearbox shift fork, which drives the synchronizer sleeve 2721 of the rear auxiliary gearbox to move forward. This connects the synchronizer sleeve 2721, the gear ring connecting sleeve 2722, the planetary gear ring 2713, the low gear ring 2723, and the central connecting plate 273 together, preventing them from rotating. The power on the second shaft 3 is transmitted to the sun gear 2715 through the spline sleeve 37. The sun gear 271, as the power input element of the rear auxiliary gearbox, transmits the power to the rear flange of the planetary gear output shaft 4 through the planetary gear unit 2712, the planetary gear ring 2713, and the planet carrier 2711, thus completing the power transmission.

[0039] The specific technical features described in the above embodiments can be combined in any suitable manner without contradiction, as long as they do not violate the spirit of the present invention, and should also be regarded as the content disclosed by the present invention.

Claims

1. A 14-speed mechanical automatic transmission, comprising a transmission housing (1), wherein a front auxiliary gearbox (101), a main gearbox (102), and a rear auxiliary gearbox (103) are arranged sequentially from front to back within the transmission housing (1); a first shaft (2) is arranged within the front auxiliary gearbox (101), a second shaft (3) is arranged within the main gearbox (102), and a planetary gear output shaft (4) is arranged within the rear auxiliary gearbox (103); the first shaft (2), the second shaft (3), and the planetary gear output shaft (4) are coaxially connected, characterized in that, The main box (102) is also provided with a left intermediate shaft (5) and a right intermediate shaft (6). The left intermediate shaft (5) and the right intermediate shaft (6) are symmetrically arranged on both sides of the two shafts (3). A first reverse gear intermediate shaft (7) is provided on the left side of the rear end of the left intermediate shaft (5), and a second reverse gear intermediate shaft (8) is provided on the right side of the rear end of the right intermediate shaft (6). The shaft (2) is provided with a speed measuring gear (9), a shaft intermediate speed dividing gear (10), a front auxiliary box synchronizer (11) and a shaft transmission gear (12) in sequence from front to back. The two shafts (3) are provided with a first sliding sleeve (13), a second gear (14), a first gear (15), a second sliding sleeve (16), a climbing gear (17), a reverse sliding sleeve (18), and a reverse gear (19) in sequence from front to back. The left intermediate shaft (5) and the right intermediate shaft (6) are respectively arranged from front to back as the intermediate shaft speed distribution gear (20), the intermediate shaft transmission gear (21), the intermediate shaft second gear (22), the intermediate shaft first gear (23), the intermediate shaft climbing gear (24), and the intermediate shaft reverse gear (25). The first reverse gear intermediate shaft (7) and the second reverse gear intermediate shaft (8) are both fitted with reverse gear intermediate wheels (26) that can mesh with the reverse gear gear (25) of the intermediate shaft. The planetary gear output shaft (4) is arranged from front to back with the following components: rear auxiliary box planetary gear assembly (27), retarder driven gear (28), output shaft speed measuring rotor (29), and odometer rotor (30).

2. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, The two shafts (3) have an open end face at one end facing the one shaft (2); The shaft (2) includes a first connecting segment (201), a second connecting segment (202) and a third connecting segment (203) that are integrally connected from front to back. The second connecting section (202) is fitted with a first thrust bearing (31), which meshes with a shaft transmission gear (12); the third connecting section (203) extends into the inner cavity; the third connecting section (203) is fitted with a two-shaft connecting sleeve (32), a second thrust bearing (33), a limiting spacer (34) and a limiting lock plate (35) in sequence from front to back; the two-shaft connecting sleeve (32) includes a connecting sleeve body (321), the front end of the connecting sleeve body (321) protrudes outward to form a protrusion (322), the protrusion (322) is connected to the first thrust bearing (31) and the two shafts (3) respectively, and the connecting sleeve body (321) is connected to the two shafts (3); the limiting spacer (34) is connected to the third connecting section (203).

3. The 14-speed mechanical automatic transmission as described in claim 2, characterized in that, A first limiting step surface is formed at the connection between the first connecting segment (201) and the second connecting segment (202), and a second limiting step surface is formed at the connection between the second connecting segment (202) and the third connecting segment (203); the front end face of the first thrust bearing (31) is grounded with the first limiting step surface, and the rear end face of the first thrust bearing (31) abuts against the front end face of the protrusion (322); the front end face of the connecting sleeve body (321) abuts against the second limiting step surface, and the rear end face of the connecting sleeve body (321) abuts against the front end face of the second thrust bearing (33); The connecting sleeve body (321) has a first retaining ring groove along the circumferential direction, and the inner wall of the inner cavity has a second retaining ring groove. The first retaining ring groove and the second retaining ring groove correspond to each other, and a retaining ring (36) is sleeved in the first retaining ring groove. The third connecting section (203) has a first limiting groove along its circumferential direction, and the limiting spacer (34) is fitted inside the first limiting groove.

4. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, The outer wall of the two shafts (3) is provided with keyways (301) that extend axially at intervals along the circumferential direction. The keyways (301) include a first keyway (3011) and a second keyway (3012) that are connected together. A third limiting step is formed at the connection between the first keyway (3011) and the second keyway (3012).

5. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, The rear auxiliary box planetary gear assembly (27) includes a planetary gear mechanism (271) and a synchronizer mechanism (272). The planetary gear mechanism (271) includes a planet carrier (2711) mounted on the planetary gear output shaft (4), a planetary gear unit (2712) mounted on the planet carrier (2711), a planetary gear ring (2713) meshing with the planetary gear unit (2712) and sliding along the axial direction of the planetary gear unit (2712), a gear ring connecting sleeve (2714) meshing with the planetary gear ring (2713), and a sun gear (2715) meshing with the planetary gear unit (2712). The sun gear (2715) is also coaxially connected to the second shaft (3). The synchronizer mechanism (272) includes a synchronizer sleeve (2721), a high-gear ring gear (2722), and a low-gear ring gear (2723); the synchronizer sleeve (2721) is connected to the ring gear connecting sleeve (2714); the high-gear ring gear (2722) is located at the axial front end of the planetary gear unit (2712) and is connected to the planetary carrier (2711); the low-gear ring gear (2723) is located at the axial front end of the high-gear ring gear (2722) and is connected to the inner wall of the transmission housing (1) via the central connecting plate (273); When in high gear, the synchronizer sleeve (2721) moves axially backward and engages with the high gear gear ring (2722) for transmission; When in low gear, the synchronizer sleeve (2721) moves forward axially and engages with the low gear ring (2723) for transmission.

6. The 14-speed mechanical automatic transmission as described in claim 5, characterized in that, The planetary gear output shaft (4) is connected to the second shaft (3) via a spline sleeve (37). The front end of the planetary gear output shaft (4) and the rear end of the second shaft (3) both extend into the spline sleeve (37) and are respectively connected to the limiting snap ring (38) arranged axially in the spline sleeve (37).

7. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, The front end of the shaft (2) is also fitted with a clutch actuator (39), which is located in front of the speed measuring gear (9).

8. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, A lubricating oil pump (40) is installed at the front end of the right intermediate shaft (6).

9. The 14-speed mechanical automatic transmission as described in claim 1, characterized in that, A brake (41) is installed at the front end of the left intermediate shaft (5).

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