Double-intermediate-shaft gearbox with planetary gear set and power split and combination

Abstract

The present application belongs to the technical field of vehicle gearbox, and provides a double-intermediate-shaft gearbox with planetary row power split and flow. The present application comprises a front sub-gearbox, a main gearbox and a rear sub-gearbox, the main gearbox output shaft and the front sub-gearbox input shaft are coaxially arranged, the double-intermediate-shaft structure comprises a first intermediate shaft and a second intermediate shaft which are symmetrically arranged according to the main gearbox output shaft, and the first intermediate shaft and the second intermediate shaft are symmetric, the front sub-gearbox input shaft is sleeved with at least two primary transmission gears, the main gearbox output shaft is sleeved with at least three tertiary transmission gears, the first intermediate shaft and the second intermediate shaft are each provided with at least five secondary transmission gears, the secondary transmission gears correspond to the primary transmission gears and the tertiary transmission gears respectively, and the rear sub-gearbox further comprises at least three gear shifting mechanisms, and the gear shifting mechanisms comprise a reverse gear shifting mechanism. The present application changes the reverse gear function in the main gearbox to the rear sub-gearbox, and adapts to the requirements of heavy truck off-road, reverse gear climbing and other multiple scene requirements.

Description

Technical Field

[0001] This invention relates to the field of vehicle transmission technology, and specifically provides a dual intermediate shaft transmission with planetary gearbox power splitting and merging. Background Technology

[0002] In the field of heavy-duty truck and off-road vehicle transmission systems, dual intermediate shaft transmissions are widely used due to their advantages such as symmetrical structure, high load-bearing capacity, and uniform gear force distribution. Traditional dual intermediate shaft transmissions typically employ a front and rear sub-section structure, with the front sub-transmission responsible for the main speed changes, while the rear sub-transmission is often used as an auxiliary gearbox or reduction mechanism. However, with the increasing demands on vehicle power and adaptability from complex operating conditions such as off-road driving, mountain transportation, and special operations, the limitations of existing transmission structures in terms of functional integration and spatial layout are gradually becoming apparent. First, in traditional transmission layouts, the reverse gear mechanism is usually located inside the main transmission. To achieve reverse gear, an idler gear transmission pair and a corresponding shifting mechanism need to be added to the main transmission. This not only disrupts the original high symmetry of the dual intermediate shaft structure but also increases the number of gears and axial dimensions inside the main transmission, resulting in a bulky overall size that is not conducive to a compact layout within the vehicle chassis. Simultaneously, due to the presence of the reverse gear mechanism, the internal structure of the main transmission is complex, making it difficult to achieve uniform lubrication and heat dissipation, which can easily lead to localized overheating. Furthermore, traditional transmissions typically have only one fixed reverse gear ratio. In scenarios requiring high torque or specific speeds, such as heavy-load reversing, hill climbing, or off-road extrication, this ratio cannot be flexibly adjusted, limiting the vehicle's maneuverability. Existing technology CN120983157A provides a dual-intermediate-shaft electric transmission with a planetary gear reduction mechanism. In this transmission, the planetary gear input shaft and the transmission input shaft are coaxially arranged with the transmission output shaft. The transmission output shaft is parallel to the first and second intermediate shafts, which are symmetrically arranged on both sides of the transmission output shaft. The planetary gear input shaft is connected to a drive motor. The planetary gear input shaft and planetary gears mesh with the internal gear rings of the planetary gears fixed to the housing. The planetary gear input shaft is coaxial with the transmission input shaft, and the transmission input shaft is coaxial with the planetary carrier in a gear meshing manner. An axial fixing device is also provided. Summary of the Invention

[0003] The purpose of this invention is to omit the reverse gear function in the front auxiliary gearbox and move it to the rear auxiliary gearbox, adapting to the needs of heavy trucks in various scenarios such as off-road driving and reverse gear climbing. Secondly, it simplifies the transmission structure of the main gearbox, reduces its size, and allows the vehicle to shift gears even when using the reverse gear function.

[0004] A planetary gearbox with dual intermediate shafts for power splitting and merging includes a front auxiliary gearbox, a main gearbox, a rear auxiliary gearbox, and a reverse gear mechanism. The rear auxiliary gearbox further includes a rear auxiliary output shaft and a rear auxiliary input shaft. The main gearbox output shaft and the rear auxiliary input shaft are poweredly connected. The main gearbox output shaft and the front auxiliary input shaft are coaxially arranged. The rear auxiliary gearbox is composed of a three-speed transmission mechanism including a reverse gear mechanism, a forward gear mechanism, and a parking mechanism. The front auxiliary gearbox is composed of a dual intermediate shaft structure, a main gearbox output shaft, and a front auxiliary input shaft. The main gearbox output shaft and the front auxiliary input shaft are coaxially arranged. The dual intermediate shaft structure includes a first intermediate shaft and a second intermediate shaft symmetrically arranged with respect to the main gearbox output shaft, and the first intermediate shaft and the second intermediate shaft are symmetrical.

[0005] The dual intermediate shaft structure includes a first intermediate shaft and a second intermediate shaft symmetrically arranged according to the output shaft of the main gearbox. The first intermediate shaft and the second intermediate shaft are symmetrical. The front auxiliary input shaft is fitted with at least two primary transmission gears, and the main gearbox output shaft is fitted with at least three tertiary transmission gears. Both the first intermediate shaft and the second intermediate shaft are equipped with at least five secondary transmission gears, and the secondary transmission gears correspond to the primary transmission gears and the tertiary transmission gears, respectively.

[0006] Power is input from the front auxiliary input shaft, then splits through a primary transmission gear to two symmetrically arranged intermediate shafts. From there, secondary transmission gears on the intermediate shafts synchronously transmit power to the tertiary transmission gear on the main gearbox output shaft, achieving power convergence. Finally, the power is transmitted to the rear auxiliary gearbox, where a three-speed transmission mechanism enables forward, parking, and reverse gearing. This technical feature transfers the reverse gear function from the traditional front auxiliary gearbox to the rear auxiliary gearbox, simplifying the transmission structure and reducing the size of both. Furthermore, the vehicle can still shift to at least two gears when using reverse, adapting to various scenarios such as heavy-duty truck off-roading and reverse-climbing.

[0007] Preferably, a connecting structure is provided between the main output shaft and the front auxiliary input shaft. The connecting structure includes a connecting pipe. The main output shaft has a first oil passage along its axis, and the front auxiliary input shaft has two through-type second oil passages along its axis. The first oil passage and the second oil passage are axially positioned by the connecting pipe.

[0008] The coaxially arranged front and auxiliary input shafts and output shafts are axially connected via a connecting pipe. This connecting pipe only serves as a transitional positioning mechanism for the lubrication system and does not transmit torque. Pressurized lubricating oil flows in from the second oil passage, transitions through the connecting pipe into the first oil passage, and provides lubrication to the transmission components on the main gearbox output shaft. This built-in oil passage structure solves the problem of multiple oil passages required for traditional coaxial rotating shaft lubrication. Compared to external lubrication pipe designs, lubricating oil can be delivered synchronously to the transmission meshing surfaces of the two intermediate shafts, and both intermediate shafts have equal amounts of lubricating oil. The floating positioning design of the connecting pipe can compensate for the coaxiality tolerance of the front and rear shafts and eliminates the need for reserved space for external pipe installation. Furthermore, since the front and auxiliary gearboxes eliminate the reverse gear mechanism, they do not need a reverse gear set or reverse idler shaft, resulting in high symmetry. Lubricating oil is supplied from the coaxially arranged and symmetrically positioned internal oil passages of the front and auxiliary input and output shafts, ensuring uniform heat dissipation efficiency and preventing localized overheating.

[0009] Preferably, the connecting pipe has protrusions at both ends, which are radially positioned with the first and second oil passages. The connecting pipe allows relative rotation between the front auxiliary input shaft and the main output shaft. The protrusions at both ends of the connecting pipe engage with the positioning grooves on the inner wall of the oil passages to achieve radial limiting, preventing the connecting pipe from shaking during shaft rotation. At the same time, a small gap is reserved between the outer wall of the connecting pipe and the inner wall of the oil passages, allowing for a speed difference between the front auxiliary input shaft and the output shaft. Lubricating oil can form a hydrodynamic oil film on the contact surface through the gap, reducing rotational friction resistance.

[0010] Preferably, the primary transmission gear includes a first transmission gear and a second transmission gear. A first engagement sleeve is provided between the first transmission gear and the second transmission gear. The first engagement sleeve has inner conical surfaces on both sides. The first transmission gear and the second transmission gear have corresponding outer conical surfaces on the side near the first engagement sleeve. The first engagement sleeve is connected to the front auxiliary input shaft for transmission. The first engagement sleeve can slide along the axial direction on the front auxiliary input shaft to selectively engage with the first transmission gear or the second transmission gear.

[0011] During gear shifting, the first engagement sleeve slides axially along the front auxiliary input shaft. The inner conical surface first contacts and rubs against the outer conical surface of the target gear, synchronizing the speed of the input shaft and the target gear. Then, the engagement sleeve fully meshes with the gear transmission teeth to achieve power transmission.

[0012] Preferably, the three-stage transmission gear also includes a third transmission gear and a second engagement sleeve. The second engagement sleeve is disposed between the third and second transmission gears and is connected to the main gearbox output shaft. The second engagement sleeve can slide axially on the main gearbox output shaft to select whether to engage with the third transmission gear. The second engagement sleeve can either mesh with the third transmission gear to achieve power transmission in the normal gear position of the front and auxiliary gearboxes, or it can be in neutral, allowing the power from the second transmission gear on the front and auxiliary input shafts to be directly transmitted to the rear auxiliary gearbox, achieving cross-stage switching of the power path.

[0013] Preferably, the second engaging sleeve has inner conical surfaces on both sides, and the third transmission gear has a corresponding outer conical surface on the side near the second engaging sleeve. The inner conical surfaces on both sides of the second engaging sleeve respectively adapt to the outer conical surfaces of the second and third transmission gears. When shifting up or down, pre-synchronization can be achieved through conical surface friction before engagement, eliminating the need for an additional reverse gear synchronization structure and enabling smooth reverse gear shifting.

[0014] Preferably, the three-stage transmission gear includes a fourth transmission gear and a fifth transmission gear. A third engaging sleeve is provided between the fourth and fifth transmission gears. The third engaging sleeve has inner conical surfaces on both sides, and the fourth and fifth transmission gears have corresponding outer conical surfaces on the sides near the third engaging sleeve. The third engaging sleeve is connected to the main gearbox output shaft and can slide axially on the main gearbox output shaft to selectively engage with either the fourth or fifth transmission gear. The third engaging sleeve controls the switching of high-speed gears. During gear shifting, rapid synchronization is achieved through the double-conical surface structure, completing the gear shifting of the fourth and fifth transmission gears and undertaking the gear adjustment function under high-speed operating conditions.

[0015] Preferably, the main gearbox output shaft is a gear shaft, comprising a first gear segment and a second gear segment. The first gear segment engages with a second coupling sleeve, and the second gear segment engages with a third coupling sleeve. The main gearbox output shaft also includes a first optical shaft segment and a second optical shaft segment, located between the first and second gear segments. The first and second optical shaft segments sequentially engage with a third transmission gear and a fourth transmission gear. The gear segments are machined with external splines that mesh with the internal splines of the coupling sleeve to transmit torque; the optical shaft segments are precision machined to engage with the inner holes of the third and fourth transmission gears in the empty sleeve, providing radial support.

[0016] Preferably, the second oil passage has a branch oil passage that connects to the inner ring of the third-stage transmission gear. Pressurized lubricating oil is directly sprayed through the branch oil passage of the second oil passage onto the mating surface between the inner ring of the empty third-stage transmission gear and the shaft, forcibly lubricating the friction pair. At the same time, the lubricating oil is thrown onto the meshing tooth surface of the gear through the radial hole inside the gear, achieving dual lubrication of the support surface and the meshing surface. Furthermore, the axial dimension of the gear section is larger than that of the smooth shaft section, and the smooth shaft section forms an annular groove, which helps to restrict the flow of lubricating oil within the smooth shaft section.

[0017] Preferably, the rear auxiliary input shaft has a first splined hub and a sun gear, and the rear auxiliary output shaft has a third splined hub and a second splined hub. The rear auxiliary gearbox also includes a planetary gear set, a first coupling mechanism, and a second coupling mechanism. The planetary gear set includes a sun gear, a ring gear, and at least one planet carrier. The planet carrier is equipped with at least two planet gears. The ring gear and the sun gear are configured to mesh with at least one planet gear. Each planet carrier is connected to the second splined hub. The first coupling mechanism is used to achieve three selective connection states: fixing or rotatable the ring gear; fixing or allowing the planet carrier to revolve around the sun gear; and engaging or disengaging the first splined hub from the planet carrier. The second coupling mechanism is used to selectively engage or disengage the third splined hub from either the ring gear or the second splined hub of the planetary gear set. The first coupling mechanism can selectively lock the ring gear and the planet carrier, or connect the first splined hub to the planet carrier. The second coupling mechanism can selectively connect the third splined hub to either the ring gear or the second splined hub. Through different combinations of states, in conjunction with the gear ratio switching between forward and reverse gears of the front auxiliary gearbox, power is input from the sun gear and output can be selected from the planet carrier or the ring gear.

[0018] This invention has the following significant advantages: The reverse gear function of the front and auxiliary gearboxes is moved to the rear auxiliary gearbox with a three-speed transmission mechanism, significantly simplifying the front and auxiliary gearboxes, achieving a compact and lightweight design, and enabling the vehicle to have multi-speed transmission capability even when reversing, perfectly adapting to harsh working conditions such as heavy-duty truck off-roading and reverse-gear hill climbing; the front and auxiliary gearboxes use coaxial built-in oil passages and are connected by floating connecting pipes, ensuring uniform heat dissipation and reliability of the dual intermediate shaft transmission, and also achieving dual lubrication of the support surface and meshing surface through branch oil passages; multiple coupling sleeves with double-cone synchronizers are integrated on the front and auxiliary input and output shafts, respectively controlling high and low gear switching and power transmission across stages, ensuring smooth and rapid gear shifting under all working conditions. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the transmission structure of the front auxiliary and main gearboxes of the present invention.

[0021] Figure 2 This is a schematic diagram of the transmission structure of the rear auxiliary gearbox of the present invention.

[0022] Figure 3 This is a three-dimensional schematic diagram of the transmission structure of the front auxiliary and main gearboxes of the present invention.

[0023] Figure 4 This is a cross-sectional view of the transmission structure of the front auxiliary and main gearboxes of the present invention.

[0024] Figure 5 For the present invention Figure 4 A magnified view of the connection structure.

[0025] Figure 6 This is a schematic diagram of the main output shaft of the present invention.

[0026] Figure 7 This is a cross-sectional view of the main output shaft of the present invention.

[0027] Legend: 1 Front auxiliary input shaft; 11 First transmission gear; 12 Second transmission gear; 13 First oil passage; 14 Connecting pipe; 21 First intermediate shaft; 22 Second intermediate shaft; 23 Secondary transmission gear; 24 First coupling sleeve; 25 Second coupling sleeve; 26 Third coupling sleeve; 3 Main gearbox output shaft; 31 Third transmission gear; 32 Fourth transmission gear; 33 Fifth transmission gear; 34 Second oil passage; 35 First gear segment; 36 Second gear segment; 37 First optical shaft segment; 38 Second optical shaft segment; 4 Rear auxiliary input shaft; 5 Rear auxiliary output shaft; 61 Sun gear; 62 Gear ring; 63 Planetary carrier; 64 Second splined hub; 65 Third splined hub; 66 First splined hub; 71 First coupling mechanism; 72 Second coupling mechanism. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Example 1 like Figure 1 and Figure 2 As shown, a dual intermediate shaft gearbox with planetary gear set power splitting and combining includes a front auxiliary gearbox at M, a main gearbox at N, and a... Figure 2 The rear auxiliary gearbox shown is as follows: Figure 3As shown, the front and auxiliary gearboxes include a dual intermediate shaft structure, a main gearbox output shaft 3, and a front and auxiliary input shaft 1. The main gearbox output shaft 3 and the front and auxiliary input shaft 1 are coaxially arranged. The dual intermediate shaft structure includes a first intermediate shaft 21 and a second intermediate shaft 22 symmetrically arranged with respect to the main gearbox output shaft 3. The front and auxiliary input shaft 1 is fitted with at least two primary transmission gears, and the main gearbox output shaft 3 is fitted with at least three tertiary transmission gears. Both the first intermediate shaft 21 and the second intermediate shaft 22 are equipped with at least five secondary transmission gears 23, which correspond to the primary and tertiary transmission gears, respectively. The front and auxiliary gearboxes do not include a reverse gear set or a reverse idler shaft. All transmission gears in the front and auxiliary gearboxes are used to form multiple forward gears and cannot individually form a reverse gear; they can only be combined to form a reverse gear. Figure 2 As shown, the rear auxiliary gearbox also includes a rear auxiliary output shaft 5 and a rear auxiliary input shaft 4. The main gearbox output shaft 3 and the rear auxiliary input shaft 4 are poweredly connected. The rear auxiliary gearbox also includes at least a three-speed transmission mechanism, which includes a reverse gear mechanism. The rear auxiliary gearbox is composed of a rear auxiliary input shaft, a rear auxiliary output shaft, and a three-speed transmission mechanism. The three-speed transmission mechanism includes a planetary gear set and at least two coupling mechanisms. The three-speed transmission mechanism can only enable the rear auxiliary gearbox to switch between forward, neutral, or reverse gear states.

[0030] like Figure 2 As shown, the rear auxiliary input shaft 4 is provided with a first splined hub 66 and a sun gear 61, and the rear auxiliary output shaft 5 is provided with a third splined hub 65 and a second splined hub 64. The rear auxiliary gearbox also includes a planetary gear set, a first coupling mechanism 71, and a second coupling mechanism 72. The planetary gear set includes a sun gear 61, a ring gear 62, and at least one planet carrier 63. The planet carrier 63 is equipped with at least two planet gears. The ring gear 62 and the sun gear 61 are configured to mesh with at least one planet gear. Each planet carrier 63 is connected to the second splined hub 64. The first coupling mechanism 71 is used to achieve three selective connection states: fixing or rotatable the ring gear 62; fixing or revolving the planet carrier 63 around the sun gear 61; and engaging or disengaging the first splined hub 66 from the planet carrier 63. The second coupling mechanism 72 is used to selectively engage or disengage the third splined hub 65 from either the ring gear 62 or the second splined hub 64 of the planetary gear set. The first coupling mechanism 71 can selectively lock the ring gear 62 and planet carrier 63, or connect the first spline hub 66 and planet carrier 63. The second coupling mechanism 72 can selectively connect the third spline hub 65 and the ring gear 62 or the second spline hub 64. Through different combinations, the gear ratios of the six forward gears and six reverse gears of the front and auxiliary transmissions are switched. Power is input from the sun gear 61 and can be output from either the planet carrier 63 or the ring gear 62. When the first coupling mechanism fixes the position of the ring gear and the second coupling mechanism engages the second spline and the third spline, the transmission path of the entire transmission mechanism is as follows: the transmission torque is transmitted along the sun gear, planet carrier, and second spline to the third spline, and the overall transmission ratio is... , z s z is the number of teeth on the sun gear. r z1 is the number of teeth on the internal gear ring, z2 is the number of teeth on the planetary gears meshing with the sun gear, and z3 is the number of teeth on the planetary gears meshing with the gear ring.

[0031] When the first coupling mechanism fixes the position of the planet carrier and the second coupling mechanism engages the gear ring with the third spline, the transmission path of the entire transmission mechanism is as follows: the transmission torque is transmitted along the sun gear, planet carrier, planet gears, and gear ring to the third spline, with a transmission ratio of... Therefore, the final result is negative, and reverse gear can be achieved in this state.

[0032] When the first coupling mechanism engages the first spline with the planet carrier, the gear ring is driven to rotate by the planet gears. When the second coupling mechanism engages the second spline with the third spline, the transmission torque is transmitted along the first spline, the first planet carrier, the second spline to the third spline, and the transmission ratio is 1.

[0033] Another idling state is provided, in which the first coupling mechanism and the second coupling mechanism make the planetary carrier and the gear ring not fixed, the second spline and the third spline disengage, and the entire transmission mechanism is in an idling state, that is, the neutral state of the transmission.

[0034] Power is input from the front auxiliary input shaft 1, then splits through a primary transmission gear to two symmetrically arranged intermediate shafts. From there, the secondary transmission gear 23 on the intermediate shafts synchronously transmits the power to the tertiary transmission gear on the main output shaft 3, achieving power convergence. Finally, the power is transmitted to the rear auxiliary gearbox, where a three-speed transmission mechanism enables gear shifting and reverse gear functionality. This technical feature moves the reverse gear function from the traditional front auxiliary gearbox to the rear auxiliary gearbox, simplifying the transmission structure and reducing the size of the front and auxiliary gearboxes. Simultaneously, it allows for gear shifting even when the vehicle is in reverse, adapting to various scenarios such as heavy-duty truck off-roading and reverse-gear hill climbing.

[0035] Combination Figure 4 and Figure 5 As shown, a connecting structure is provided between the main output shaft 3 and the front auxiliary input shaft 1. The connecting structure includes a connecting pipe 14. The main output shaft 3 has a first oil passage 13 along the axis inside, and the front auxiliary input shaft 1 has two through second oil passages 34 along the axis inside. The first oil passage 13 and the second oil passage 34 are axially positioned by the connecting pipe 14.

[0036] The coaxially arranged front and auxiliary input shafts 1 and output shafts are axially connected via connecting pipe 14. Connecting pipe 14 only serves as a transitional positioning function for the lubrication circuit and does not transmit torque. Pressurized lubricating oil flows in from the second oil passage 34, transitions through connecting pipe 14 to the first oil passage 13, and provides lubrication medium for the transmission components on the main gearbox output shaft 3. This built-in oil circuit structure solves the problem of multiple oil passages required for lubrication of traditional coaxial rotating shafts. Compared with external lubrication pipeline design, lubricating oil can be delivered to the transmission meshing surfaces of the two intermediate shafts simultaneously, and both intermediate shafts have an equal amount of lubricating oil. The floating positioning design of connecting pipe 14 can compensate for the installation coaxiality tolerance of the front and rear shafts and eliminates the need to reserve space for external pipeline installation. At the same time, since the reverse gear mechanism is eliminated in the front and auxiliary gearboxes, the front and auxiliary gearboxes have a high degree of symmetry. The supply of lubricating oil from the coaxially arranged front and auxiliary input shafts 1 and output shafts located on the line of symmetry ensures uniform heat dissipation efficiency of the entire front and auxiliary gearboxes and avoids local overheating.

[0037] like Figure 5 As shown, the connecting pipe 14 has protrusions at both ends, which are radially positioned with the first oil passage 13 and the second oil passage 34. The connecting pipe 14 allows relative rotation between the front auxiliary input shaft 1 and the main output shaft 3. The protrusions at both ends of the connecting pipe 14 engage with the positioning grooves on the inner wall of the oil passage to achieve radial limiting, preventing the connecting pipe 14 from shaking during the rotation of the shaft. At the same time, a small gap is reserved between the outer wall of the connecting pipe 14 and the inner wall of the oil passage, allowing a speed difference between the front auxiliary input shaft 1 and the output shaft. The lubricating oil can form a dynamic pressure oil film on the contact surface through the gap, reducing rotational friction resistance.

[0038] Combination Figure 1 and Figure 4 As shown, the primary transmission gear includes a first transmission gear 11 and a second transmission gear 12. A first engagement sleeve 24 is provided between the first transmission gear 11 and the second transmission gear 12. The first engagement sleeve 24 has inner conical surfaces on both sides, and the first transmission gear 11 and the second transmission gear 12 have corresponding outer conical surfaces on the side near the first engagement sleeve 24. The first engagement sleeve 24 is connected to the front auxiliary input shaft 1 for transmission. The first engagement sleeve 24 can slide along the axial direction on the front auxiliary input shaft 1 to selectively engage with the first transmission gear 11 or the second transmission gear 12, realizing the selection... Figure 1 The gear position shown at point A or point B.

[0039] like Figure 4 As shown, during gear shifting, the first engagement sleeve 24 slides axially along the front auxiliary input shaft 1. The inner conical surface first contacts and rubs against the outer conical surface of the target gear transmission gear to achieve synchronization of the speed of the input shaft and the target gear. Then, the engagement sleeve fully meshes with the gear transmission teeth to achieve power transmission.

[0040] like Figure 4As shown, the three-stage transmission gear also includes a third transmission gear 31 and a second engagement sleeve 25. The second engagement sleeve 25 is disposed between the third transmission gear 31 and the second transmission gear 12. The second engagement sleeve 25 is connected to the main gearbox output shaft 3. The second engagement sleeve 25 can slide axially on the main gearbox output shaft 3 to select whether to engage with the third transmission gear 31. The second engagement sleeve 25 can either mesh with the third transmission gear 31 to realize the power transmission of the front and auxiliary gearboxes in the normal gear position, or it can be in neutral, allowing the power of the second transmission gear 12 of the front and auxiliary input shafts 1 to be directly transmitted to the rear auxiliary gearbox, realizing the cross-stage switching of the power path, that is, realizing the selection of... Figure 1 The gear position shown at point C or F.

[0041] The second engaging sleeve 25 has inner conical surfaces on both sides, and the third transmission gear 31 has a corresponding outer conical surface on the side near the second engaging sleeve 25. The inner conical surfaces on both sides of the second engaging sleeve 25 are respectively adapted to the outer conical surfaces of the second transmission gear 12 and the third transmission gear 31. When shifting up or down, pre-synchronization can be achieved through conical surface friction before engagement is completed. Smooth reverse gear shifting can be achieved without the need for an additional reverse gear synchronization structure.

[0042] The three-stage transmission gear system includes a fourth transmission gear 32 and a fifth transmission gear 33. A third engagement sleeve 26 is provided between the fourth transmission gear 32 and the fifth transmission gear 33. The third engagement sleeve 26 has inner conical surfaces on both sides, and the fourth transmission gear 32 and the fifth transmission gear 33 have corresponding outer conical surfaces on the side closest to the third engagement sleeve 26. The third engagement sleeve 26 is connected to the main housing output shaft 3 for transmission. The third engagement sleeve 26 can slide axially on the main housing output shaft 3 to selectively engage with either the fourth transmission gear 32 or the fifth transmission gear 33, thus achieving selective engagement. Figure 1 The gear position is shown at point D or E. The third engagement sleeve 26 controls the switching of high-speed gears. During gear shifting, rapid synchronization is achieved through the double conical surface structure, completing the gear switching between the fourth transmission gear 32 and the fifth transmission gear 33, and undertaking the gear adjustment function under high-speed conditions.

[0043] like Figure 6 As shown, the main gearbox output shaft 3 is a gear shaft, comprising a first gear segment 35 and a second gear segment 36. The first gear segment 35 engages with the second coupling sleeve 25, and the second gear segment 36 engages with the third coupling sleeve 26. The main gearbox output shaft 3 also includes a first optical shaft segment 37 and a second optical shaft segment 38, located between the first gear segment 35 and the second gear segment 36. The first optical shaft segment 37 and the second optical shaft segment 38 sequentially engage with the third transmission gear 31 and the fourth transmission gear 32. The gear segments are machined with external splines that mesh with the internal splines of the coupling sleeve to transmit torque; the optical shaft segments are precision machined to engage with the inner holes of the third and fourth transmission gears in the empty sleeve, providing radial support.

[0044] like Figure 7 As shown, the second oil passage 34 has a branch oil passage that connects to the inner ring of the third-stage transmission gear. Pressurized lubricating oil is directly sprayed through the branch oil passage of the second oil passage 34 onto the mating surface between the inner ring of the empty third-stage transmission gear and the shaft, forcibly lubricating the friction pair. At the same time, the lubricating oil is thrown onto the meshing tooth surface of the gear through the radial hole inside the gear, achieving dual lubrication of the support surface and the meshing surface.

[0045] The present invention has the following significant advantages: by moving the reverse gear function of the front auxiliary gearbox to the rear auxiliary gearbox with a three-speed transmission mechanism, the front and auxiliary gearboxes are significantly simplified, achieving a compact and lightweight design, and enabling the vehicle to have multi-speed transmission capability even when reversing, perfectly adapting to harsh working conditions such as heavy truck off-roading and reverse gear climbing; the front and auxiliary gearboxes adopt coaxial built-in oil passages and are connected through floating connecting pipe 14, ensuring uniform heat dissipation and reliability of the dual intermediate shaft transmission, and also achieving dual lubrication of the support surface and meshing surface through branch oil passages; multiple coupling sleeves with double conical surface synchronizers are integrated on the front and auxiliary input shafts 1 and output shafts, respectively controlling the switching of high and low gears and the cross-stage transmission of power, ensuring smooth and rapid gear shifting under all working conditions.

[0046] The above embodiments and / or implementation methods are merely illustrative of preferred embodiments and / or implementation methods for realizing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art may make some modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but these should still be regarded as the technology or embodiments that are substantially the same as the present invention.

Claims

1. A planetary gearbox with dual intermediate shafts for power splitting and merging, comprising a front auxiliary gearbox, a main gearbox, a rear auxiliary gearbox, and a reverse gear mechanism, wherein the rear auxiliary gearbox further comprises a rear auxiliary output shaft (4) and a rear auxiliary input shaft (3), characterized in that, The rear auxiliary gearbox is composed of a three-speed transmission mechanism including a reverse gear mechanism. The front auxiliary gearbox is composed of a double intermediate shaft structure, a main gearbox output shaft and a front auxiliary input shaft (1). The main gearbox output shaft and the rear auxiliary input shaft (3) are poweredly connected. The rear auxiliary input shaft (3) and the front auxiliary input shaft (1) are arranged coaxially. The double intermediate shaft structure includes a first intermediate shaft (21) and a second intermediate shaft (22) symmetrically arranged according to the main gearbox output shaft, and the first intermediate shaft (21) and the second intermediate shaft (22) are symmetrical.

2. The dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 1, characterized in that, The front auxiliary input shaft (1) is fitted with at least two primary transmission gears, and the main output shaft (3) is fitted with at least three tertiary transmission gears. The first intermediate shaft (21) and the second intermediate shaft (22) are each equipped with at least five secondary transmission gears (23). The secondary transmission gears (23) correspond to the primary transmission gears and the tertiary transmission gears, respectively. A connecting structure is provided between the main output shaft (3) and the front auxiliary input shaft (1). The connecting structure includes a connecting pipe (14). The main output shaft (3) is provided with a first oil passage (13) along the axis inside. The front auxiliary input shaft (1) is provided with two through-flow second oil passages (34) along the axis inside. The first oil passage (13) and the second oil passage (34) are axially positioned by the connecting pipe (14).

3. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 2, characterized in that, The connecting pipe (14) has protrusions at both ends of its edges. The protrusions are radially positioned with the first oil passage (13) and the second oil passage (34). The connecting pipe (14) allows the front auxiliary input shaft (1) and the main output shaft (3) to rotate relative to each other.

4. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 2, characterized in that, The primary transmission gear includes a first transmission gear (11) and a second transmission gear (12). A first engagement sleeve (24) is provided between the first transmission gear (11) and the second transmission gear (12). The first engagement sleeve (24) has inner conical surfaces on both sides. The first transmission gear (11) and the second transmission gear (12) have corresponding outer conical surfaces on the side near the first engagement sleeve (24). The first engagement sleeve (24) is connected to the front auxiliary input shaft (1) for transmission. The first engagement sleeve (24) can slide along the axial direction on the front auxiliary input shaft (1) to select engagement with the first transmission gear (11) or the second transmission gear (12).

5. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 4, characterized in that, The three-stage transmission gear also includes a third transmission gear (31) and a second engagement sleeve (25). The second engagement sleeve (25) is disposed between the third transmission gear (31) and the second transmission gear (12). The second engagement sleeve (25) is connected to the main output shaft (3) for transmission. The second engagement sleeve (25) can slide along the axial direction on the main output shaft (3) to select whether to engage with the third transmission gear (31).

6. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 5, characterized in that, The second coupling sleeve (25) has inner conical surfaces on both sides, and the third transmission gear (31) has a corresponding outer conical surface on the side near the second coupling sleeve (25).

7. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 5, characterized in that, The three-stage transmission gear includes a fourth transmission gear (32) and a fifth transmission gear (33). A third engagement sleeve (26) is provided between the fourth transmission gear (32) and the fifth transmission gear (33). The third engagement sleeve (26) has inner conical surfaces on both sides. The fourth transmission gear (32) and the fifth transmission gear (33) have corresponding outer conical surfaces on the side near the third engagement sleeve (26). The third engagement sleeve (26) is connected to the main box output shaft (3) for transmission. The third engagement sleeve (26) can slide along the axial direction on the main box output shaft (3) to select engagement with the fourth transmission gear (32) or the fifth transmission gear (33).

8. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 7, characterized in that, The main output shaft (3) is a gear shaft. The main output shaft (3) includes a first gear segment (35) and a second gear segment (36). The first gear segment (35) cooperates with the second engagement sleeve (25), and the second gear segment (36) cooperates with the third engagement sleeve (26). The main output shaft (3) also includes a first optical shaft segment (37) and a second optical shaft segment (38). The first optical shaft segment (37) and the second optical shaft segment (38) are located between the first gear segment (35) and the second gear segment (36). The first optical shaft segment (37) and the second optical shaft segment (38) cooperate with the third transmission gear (31) and the fourth transmission gear (32) in sequence.

9. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 2, characterized in that, The second oil passage (34) is provided with a branch oil passage, which is connected to the inner ring of the third-stage transmission gear.

10. A dual intermediate shaft gearbox for planetary gearbox power splitting and merging according to claim 1, characterized in that, The rear auxiliary input shaft (4) is provided with a first splined hub (66) and a sun gear (61), and the rear auxiliary output shaft (5) is provided with a third splined hub (65) and a second splined hub (64). The rear auxiliary gearbox also includes a planetary gear set, a first coupling mechanism (71), and a second coupling mechanism (72). The planetary gear set includes a sun gear (61), a ring gear (62), and at least one planet carrier (63). The planet carrier (63) is equipped with at least two planet gears. The ring gear (62) and the sun gear (61) are configured to mesh with the at least one planet gear. Each of the planetary carriers (63) is connected to a second splined hub (64); the first coupling mechanism (71) is used to achieve three selective connection states: fixing or rotatable the gear ring (62); fixing or revolving the planetary carrier (63) around the sun gear (61); and engaging or disengaging the first splined hub (66) from the planetary carrier (63); the second coupling mechanism (72) is used to selectively engage or disengage the third splined hub (65) from either the gear ring (62) or the second splined hub (64) of the planetary gear set.

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