low speed heavy duty longitudinal transmission

Abstract

This utility model relates to the technical field of motor vehicle transmissions, and discloses a low-speed, heavy-duty, longitudinally mounted transmission. Through the engagement and disengagement of a first, second, third, and fourth clutch, in conjunction with a first, second, third, and fourth planetary gear set assembly, it achieves the switching of multiple forward gears and one reverse gear. Furthermore, by engaging the fourth clutch on a fifth rotating shaft, the third and fourth rotating shafts rotate synchronously. Simultaneously, because the fifth rotating shaft is directly or indirectly connected to the third sun gear and the third planetary carrier, the torque at the engagement of the fourth clutch is relatively small, solving the technical problem in existing technologies where the torque at clutch engagement is large, easily causing transmission damage. This achieves the technical effect of reducing the torque at the fourth clutch and avoiding transmission damage.

Description

Technical Field

[0001] This utility model relates to the field of motor vehicle transmission technology, and in particular to a low-speed, heavy-duty, longitudinally mounted transmission. Background Technology

[0002] A car transmission is a gearbox that coordinates the engine speed and the actual speed of the wheels to optimize engine performance. During vehicle operation, the transmission can create different gear ratios between the engine and wheels, enabling the transmission of different engine speeds.

[0003] Transmissions are divided into manual and automatic types. Manual transmissions are mainly composed of gears and shafts, and different gear combinations produce speed and torque changes. Automatic transmissions (AT) are composed of a torque converter, planetary gears and a hydraulic control system, and achieve speed and torque changes through hydraulic transmission and gear combinations.

[0004] Automatic transmissions, with their advantages of improved driving comfort and reduced driver fatigue, have become a popular trend in modern car configurations. They utilize planetary gear mechanisms to change gears automatically based on accelerator pedal pressure and vehicle speed. Drivers only need to operate the accelerator pedal to control speed, allowing them to focus entirely on the road without the hassle of manual shifting.

[0005] In most transmissions, there are multiple forward gears and one reverse gear, and the transmission can have a high starting gear ratio in the forward direction. Because current transmissions have multiple components for shifting, most achieve shifting through the opening and closing of different clutches. Clutches are engaged and disengaged through the friction and separation of rotating discs and friction plates. However, the engagement of the friction plates and rotating discs in the clutch results in a large torque at the clutch engagement point, which can easily damage the transmission. Utility Model Content

[0006] The purpose of this invention is to provide a low-speed, heavy-load longitudinal transmission that solves the technical problem in the prior art where the torque at the clutch engagement point is too large, which easily causes damage to the transmission.

[0007] To solve the above-mentioned technical problems, this utility model provides a low-speed heavy-duty longitudinal transmission, including: a housing, an input shaft, an output shaft, a first planetary gear set assembly, a second planetary gear set assembly, a third planetary gear set assembly, a fourth planetary gear set assembly, a first clutch, a second clutch, a third clutch, and a fourth clutch.

[0008] The first planetary gear set includes a first sun gear, a first planetary gear, a first planet carrier, and a first ring gear; the second planetary gear set includes a second sun gear, a second planetary gear, a second planet carrier, and a second ring gear; the third planetary gear set includes a third sun gear, a third planetary gear, a third planet carrier, and a third ring gear; the fourth planetary gear set includes a fourth sun gear, a fourth planetary gear, a fourth planet carrier, and a fourth ring gear.

[0009] The input shaft is connected to the second clutch and the second planetary carrier, respectively.

[0010] The first planetary carrier is connected to the first clutch via a second rotating shaft, the first gear ring is fixedly mounted on the inner wall of the housing, and the first sun gear is connected to the inner wall of the housing;

[0011] The second gear ring is connected to the third sun gear via a third rotating shaft;

[0012] The third rotating shaft is connected to the fourth rotating shaft via the fifth rotating shaft, the fourth clutch is disposed on the fifth rotating shaft, and the third planetary carrier is connected to the third clutch via the fourth rotating shaft;

[0013] The third gear ring is connected to the second clutch via the sixth rotating shaft;

[0014] The fourth sun gear is connected to the sixth shaft, the fourth planetary carrier is connected to the third clutch via the seventh shaft, and the output shaft is connected to the fourth planetary carrier via a transmission.

[0015] The fourth gear ring is connected to the first clutch via the eighth rotating shaft.

[0016] In an optional embodiment, the output shaft is drive-connected to the seventh shaft disposed on the fourth planetary carrier.

[0017] In an optional embodiment, the input shaft and the output shaft are coaxially arranged.

[0018] In an optional implementation, the first planetary gear set, the second planetary gear set, the third planetary gear set, and the fourth planetary gear set are arranged sequentially along the axial direction of the output shaft.

[0019] In an optional implementation, a brake is also included;

[0020] The brake is fixedly installed on the inner wall of the housing, and the brake is connected to the first sun gear and the second sun gear respectively through the first rotating shaft.

[0021] In an optional embodiment, a hydraulic assembly is further included, which is connected to the brake, the first clutch, the second clutch, the third clutch, and the fourth clutch, respectively, and the hydraulic assembly is used to provide oil pressure to the brake, the first clutch, the second clutch, the third clutch, and the fourth clutch.

[0022] In an optional implementation, the low-speed, heavy-duty longitudinal transmission includes eight forward gears and one reverse gear:

[0023] The first forward gear is achieved by closing the brake, the first clutch, and the second clutch;

[0024] The second forward gear is achieved by closing the brake, the first clutch, and the fourth clutch;

[0025] The third forward gear is achieved by engaging the first clutch, the second clutch, and the fourth clutch;

[0026] The fourth forward gear is achieved by engaging the first clutch, the third clutch, and the fourth clutch;

[0027] The fifth forward gear is achieved by engaging the first clutch, the second clutch, and the third clutch;

[0028] The sixth forward gear is achieved by engaging the second clutch, the third clutch, and the fourth clutch;

[0029] The seventh forward gear is achieved by closing the brake, the second clutch, and the third clutch;

[0030] The eighth forward gear is achieved by closing the brake, the third clutch, and the fourth clutch;

[0031] Reverse gear is achieved by closing the brake, the first clutch, and the third clutch.

[0032] In an optional embodiment, a hydraulic torque converter is further included, which is disposed within the housing, with one end connected to the engine and the other end connected to the input shaft.

[0033] This utility model provides a low-speed, heavy-duty longitudinally mounted transmission that can be applied to automobiles. During operation, the driver can engage and disengage the first, second, third, and fourth clutches, in conjunction with the first, second, third, and fourth planetary gear sets, to switch between multiple forward gears and one reverse gear. By engaging the fourth clutch on the fifth shaft, the third and fourth shafts rotate synchronously. Furthermore, because the fifth shaft is directly or indirectly connected to the third sun gear and the third planetary carrier, the torque at the engagement of the fourth clutch is relatively low. This solves the technical problem in existing technologies where the torque at the clutch engagement point is high, easily causing transmission damage. The goal is to achieve the technical effect of lower torque at the fourth clutch and avoid transmission damage. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the low-speed heavy-load longitudinal transmission mentioned in the embodiments of this utility model;

[0035] Figure 2 This is a schematic diagram of the shifting logic of the low-speed heavy-load longitudinal transmission mentioned in the embodiments of this utility model.

[0036] In the diagram, P1 is the first planetary gear set; 10 is the first sun gear; 11 is the first planetary carrier; 12 is the first ring gear; P2 is the second planetary gear set; 20 is the second sun gear; 21 is the second planetary carrier; 22 is the second ring gear; P3 is the third planetary gear set; 30 is the third sun gear; 31 is the third planetary carrier; 32 is the third ring gear; P4 is the fourth planetary gear set; 40 is the fourth sun gear; 41 is the fourth planetary carrier; 42 is the fourth ring gear; 50 is the housing; 51 is the input shaft; 52 is the output shaft; 60 is the brake; 61 is the first clutch; 62 is the second clutch; 63 is the third clutch; 64 is the fourth clutch; 71 is the first shaft; 72 is the second shaft; 73 is the third shaft; 74 is the fourth shaft; 75 is the fifth shaft; 76 is the sixth shaft; 77 is the seventh shaft; 78 is the eighth shaft. Detailed Implementation

[0037] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0038] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 this utility model based on the specific circumstances.

[0039] like Figure 1 As shown, some embodiments of this application provide a low-speed, heavy-duty longitudinally mounted transmission including a housing 50, an input shaft 51, an output shaft 52, a first planetary gear set P1, a second planetary gear set P2, a third planetary gear set P3, a fourth planetary gear set P4, a brake 60, a first clutch 61, a second clutch 62, a third clutch 63, and a fourth clutch 64. The brake 60 connects the rotating shafts and controls their axial degree of freedom. Specifically, when the brake 60 is closed, the rotating shaft connected to it is locked and will not rotate circumferentially; when the brake 60 is open, the rotation of the connected rotating shaft is unrestricted. The clutch in this transmission connects two rotating shafts. When the clutch is closed, the two rotating shafts connected to it can rotate synchronously; when the clutch is disengaged, the two rotating shafts connected to it can rotate relative to each other.

[0040] The first planetary gear set P1 includes a first sun gear 10, a first planetary gear, a first planet carrier 11, and a first ring gear 12; the second planetary gear set P2 includes a second sun gear 20, a second planetary gear, a second planet carrier 21, and a second ring gear 22; the third planetary gear set P3 includes a third sun gear 30, a third planetary gear, a third planet carrier 31, and a third ring gear 32; and the fourth planetary gear set P4 includes a fourth sun gear 40, a fourth planetary gear, a fourth planet carrier 41, and a fourth ring gear 42. The transmission process and principle of the planetary gear sets are well known to those skilled in the art and therefore will not be described in detail.

[0041] like Figure 1 As shown, the input shaft 51 is connected to the second clutch 62 and the second planetary carrier 21. Specifically, the rotation of the input shaft 51 can drive the second planetary carrier 21 to rotate. When the second clutch 62 is closed, the input shaft 51 can drive another rotating shaft connected to the second clutch 62 to rotate; when the second clutch 62 is open, the input shaft 51 can rotate relative to the other rotating shaft through the second clutch 62.

[0042] The brake 60 is fixedly mounted on the inner wall of the housing 50, and is connected to the first sun gear 10 and the second sun gear 20 via a first rotating shaft 71. The rotation or locking of the first rotating shaft 71 can be controlled by opening or closing the brake 60. Specifically, when the brake 60 is closed, the first rotating shaft 71 will not rotate, i.e., it will be stationary relative to the housing 50; therefore, the first sun gear 10 and the second sun gear 20 will also not rotate. When the brake 60 is open, the first rotating shaft 71 can rotate relative to the brake 60, and consequently, the first sun gear 10 and the second sun gear 20 connected to it can both rotate.

[0043] The first planetary carrier 11 is connected to the first clutch 61 via the second rotating shaft 72, and the first gear ring 12 is fixedly mounted on the inner wall of the housing 50. Since the first gear ring 12 is fixed to the inner wall of the housing 50, it will not rotate. When the input shaft 51 drives the second planetary carrier 21 to rotate, if the brake 60 is closed, the first rotating shaft 71 will not rotate, and correspondingly, the first sun gear 10, the first planetary carrier 11, and the second rotating shaft 72 will also not rotate. If the brake 60 is open, the rotation of the second planetary carrier 21 drives the second sun gear 20 and the first rotating shaft 71 to rotate, which in turn drives the first sun gear 10 to rotate, and the first sun gear 10 in turn drives the first planetary carrier 11 and the second rotating shaft 72 to rotate.

[0044] The second gear ring 22 is connected to the third sun gear 30 via the third rotating shaft 73. The rotation of the second gear ring 22 can drive the third sun gear 30 to rotate. The third rotating shaft 73 is connected to the fourth rotating shaft 74 via the fifth rotating shaft 75. The fourth clutch 64 is mounted on the fifth rotating shaft 75. The third planetary carrier 31 is connected to the third clutch 63 via the fourth rotating shaft 74. The third gear ring 32 is connected to the second clutch 62 via the sixth rotating shaft 76.

[0045] The connection or disconnection of the input shaft 51 and the sixth shaft 76 is controlled by the engagement and disengagement of the second clutch 62. When the second clutch 62 is engaged, the input shaft 51 and the sixth shaft 76 rotate synchronously; when the second clutch 62 is disengaged, the input shaft 51 and the sixth shaft 76 can rotate relative to each other. The fifth shaft 75 has a third shaft 73 and a fourth shaft 74 respectively connected to its two ends. A fourth clutch 64 can be installed in the middle of the fifth shaft 75, dividing the fifth shaft 75 into two sections. When the fourth clutch 64 is engaged, the third shaft 73 can drive the fourth shaft 74 to rotate through the fifth shaft 75, causing the third shaft 73 and the fourth shaft 74 to rotate synchronously, thereby causing the second ring gear 22, the third sun gear 30, and the third planetary carrier 31 to rotate synchronously. When the fourth clutch 64 is disengaged, the third shaft 73 can rotate relative to the fourth shaft 74. By combining the fourth clutch 64 on the fifth shaft 75, the third shaft 73 and the fourth shaft 74 can rotate synchronously. At the same time, since the fifth shaft 75 is directly or indirectly connected to the third sun gear 30 and the third planetary carrier 31, the torque at the fourth clutch 64 on the fifth shaft 75 can be reduced, effectively increasing the service life of the low-speed heavy-duty longitudinal transmission and avoiding damage.

[0046] The fourth sun gear 40 is connected to the sixth shaft 76, and the rotation of the sixth shaft 76 drives the fourth sun gear 40 to rotate. The fourth planetary carrier 41 is connected to the third clutch 63 via the seventh shaft 77, and the connection relationship between the fourth shaft 74 and the seventh shaft 77 can be controlled by the third clutch 63. Specifically, when the third clutch 63 is closed, the fourth shaft 74 and the seventh shaft 77 rotate synchronously; when the third clutch 63 is open, the fourth shaft 74 and the seventh shaft 77 can rotate relative to each other. The output shaft 52 is driven by the fourth planetary carrier 41, and the rotation of the fourth planetary carrier 41 drives the output shaft 52 to rotate. Preferably, the output shaft 52 is connected to the seventh shaft 77 mounted on the fourth planetary carrier 41, saving equipment costs and reducing space occupation. Specifically, the seventh shaft 77 passes through the fourth planetary carrier 41, with one end of the seventh shaft 77 connected to the output shaft 52 and the other end connected to the third clutch 63. Alternatively, a seventh shaft 77 can be provided at both ends of the fourth planetary carrier 41. The output end of one seventh shaft 77 is connected to the third clutch 63, and the output end of the other seventh shaft 77 is connected to the output shaft 52. The fourth gear ring 42 is connected to the first clutch 61 via an eighth shaft 78, and the connection between the second shaft 72 and the eighth shaft 78 is controlled by the first clutch 61. Specifically, when the first clutch 61 is closed, the second shaft 72 and the eighth shaft 78 rotate synchronously; when the first clutch 61 is open, both the second shaft 72 and the eighth shaft 78 rotate relative to the first clutch 61. The input shaft 51 and the output shaft 52 are coaxially arranged, which can effectively reduce the space occupied by the low-speed heavy-load longitudinal transmission.

[0047] Combination Figure 1 and Figure 2 As shown, the first planetary gear set P1, the second planetary gear set P2, the third planetary gear set P3, and the fourth planetary gear set P4 are arranged sequentially along the direction towards the output shaft 52, facilitating the installation of the low-speed, heavy-duty longitudinally mounted transmission. Furthermore, the arrangement of the planetary gear sets in this application is not limited to this specific arrangement; operators can reasonably adjust the positions of the first planetary gear set P1, the second planetary gear set P2, the third planetary gear set P3, and the fourth planetary gear set P4 according to the internal space of the housing 50 and the distance relationships between the mechanical components.

[0048] The low-speed heavy-duty longitudinal transmission provided in this application can achieve three drive modes: pure electric, engine-driven, and hybrid. During operation, the driver can engage and disengage the first clutch 61, second clutch 62, third clutch 63, and fourth clutch 64, in conjunction with the first planetary gear set P1, second planetary gear set P2, third planetary gear set P3, and fourth planetary gear set P4, to switch between multiple forward gears and one reverse gear. By engaging the fourth clutch 64 on the fifth rotating shaft 75, the third rotating shaft 73 and the fourth rotating shaft 74 rotate synchronously. Furthermore, since the fifth rotating shaft 75 is directly or indirectly connected to the third sun gear 30 and the third planetary carrier 31, the torque at the engagement of the fourth clutch 64 is relatively small. This solves the technical problem in existing technologies where the torque at the clutch engagement point is large, easily causing transmission damage, thus achieving the technical effect of lower torque at the fourth clutch and avoiding transmission damage. By combining the above components, the fatigue safety factor of some gears is increased, the damage rate of some bearings is reduced, thereby increasing the safety factor and service life of the low-speed heavy-duty longitudinal transmission. In addition, this combination method effectively reduces the number of internal components of the low-speed heavy-duty longitudinal transmission and reduces manufacturing costs.

[0049] The low-speed, heavy-duty longitudinal transmission includes not only the aforementioned planetary gear mechanism, but also a torque converter, a dual-mass flywheel, a hybrid module, a hydraulic system, a shift unit, a hydraulic pump, and an electric pump. The torque converter is housed within the housing 50, with one end connected to the engine and the other end connected to the input shaft 51. The hybrid module is connected to both the dual-mass flywheel and the input end of the input shaft 51. The hydraulic system provides hydraulic pressure to the brake 60, the first clutch 61, the second clutch 62, the third clutch 63, and the fourth clutch 64, thereby controlling their opening and closing, and also provides lubrication. Since these components are relatively common in low-speed, heavy-duty longitudinal transmissions, they are not described in detail.

[0050] like Figure 2As shown, the low-speed, heavy-duty longitudinal transmission includes eight forward gears and one reverse gear. Different gears can be shifted through five shifting components, four planetary gear sets, and various combinations of multiple shafts. The specific shifting operation is as follows:

[0051] First forward gear: Close the brake 60, first clutch 61 and second clutch 62; release the third clutch 63 and fourth clutch 64.

[0052] Because brake 60 is closed, the first shaft 71 will not rotate, causing the first planetary carrier 11 and the second shaft 72 to stop rotating. Because the first clutch 61 is closed, the second shaft 72 and the eighth shaft 78 are connected, therefore the eighth shaft 78 will also not rotate. Simultaneously, because the third clutch 63 and the fourth clutch 64 are open, power cannot be transmitted to the output shaft 52 via the third planetary carrier 31. Because the second clutch 62 is closed, power can be transmitted from the input shaft 51 to the sixth shaft 76. Since the fixed eighth shaft 78 is connected to the fourth ring gear 42, the fourth ring gear 42 is fixed, and the sixth shaft 76 drives the fourth sun gear 40 to rotate, thereby driving the output shaft 52 to rotate.

[0053] Second forward gear: Close brake 60, first clutch 61 and fourth clutch 64; release second clutch 62 and third clutch 63.

[0054] Because the second clutch 62 is open, the input shaft 51 cannot directly drive the sixth shaft 76 to rotate. The third clutch 63 is disengaged, therefore, the seventh shaft 77 cannot be driven to rotate via the fourth shaft 74. Because the brake 60 and the first clutch 61 are closed, according to the principle of the first forward gear, the first shaft 71 and the eighth shaft 78 will not rotate. The power from the input shaft 51 is transmitted to the third shaft 73 via the second planetary gear assembly P2. Because the fourth clutch 64 is closed, the rotation of the third sun gear 30 drives the fourth shaft 74 and the fifth shaft 75 to rotate synchronously. Because the third clutch 63 is released, the third planetary gear assembly P3 transmits power to the sixth shaft 76, and then through the fourth planetary gear assembly P4 to the output shaft 52, completing the power transmission.

[0055] Third forward gear: Close the first clutch 61, the second clutch 62 and the fourth clutch 64; release the brake 60 and the third clutch 63.

[0056] Power is input through input shaft 51. Because brake 60 is disengaged, first shaft 71 can rotate with second sun gear 20, thereby driving first sun gear 10 to rotate. First sun gear 10 then drives first planetary carrier 11 and second shaft 72 to rotate. Because first clutch 61 is engaged, second shaft 72 can drive eighth shaft 78 to rotate, thus power can be transmitted to fourth ring gear 42. Because second clutch 62 and fourth clutch 64 are engaged, power can be transmitted through sixth shaft 76 to the sun gear of fourth planetary gear assembly P4, thereby driving output shaft 52 to rotate, completing the power transmission.

[0057] Fourth forward gear: Close the first clutch 61, the third clutch 63 and the fourth clutch 64; release the brake 60 and the second clutch 62.

[0058] Power is input through the input shaft 51. Because the brake 60 is disengaged and the first clutch 61 is engaged, as can be seen from the principle of the third forward gear, the power from the input shaft 51 can be transmitted to the third sun gear 30. Because the fourth clutch 64 and the third clutch 63 are engaged, the power can be transmitted to the seventh shaft 77, thereby causing the output shaft 52 to rotate.

[0059] Fifth forward gear: Close the first clutch 61, the second clutch 62 and the third clutch 63; release the brake 60 and the fourth clutch 64.

[0060] Power is input through the input shaft 51. Because the brake 60 is disengaged and the first clutch 61 is engaged, power can be transmitted to the third ring gear 32. Because the second clutch 62 is engaged, power can be directly transmitted through the input shaft 51 to the sixth shaft 76, and then to the third ring gear 32. Because the fourth clutch 64 is disengaged and the third clutch 63 is engaged, the third planetary carrier 31 can output power to the output shaft 52.

[0061] Sixth forward gear: Close the second clutch 62, the third clutch 63 and the fourth clutch 64; release the brake 60 and the first clutch 61.

[0062] With the second clutch 62 engaged, the power from the input shaft 51 can be directly transmitted to the sixth shaft 76, and then to the third ring gear 32. Since both the brake 60 and the first clutch 61 are engaged, power cannot be transmitted to the fourth ring gear 42 via the first planetary carrier 11. With the third clutch 63 engaged, the third planetary carrier 31 can transmit power to the output shaft 52. Furthermore, with the fourth clutch 64 engaged, the third planetary carrier 31 and the third sun gear 30 rotate at the same speed.

[0063] Seventh forward gear: Close the brake 60, the second clutch 62 and the third clutch 63; release the first clutch 61 and the fourth clutch 64.

[0064] Power is input through input shaft 51. Because brake 60 is closed and first clutch 61 is open, first shaft 71 is stationary. At the same time, the power from input shaft 51 is transmitted to second ring gear 22 through second planetary carrier 21, and then to third sun gear 30. Because second clutch 62 and third clutch 63 are closed, the power from input shaft 51 can be transmitted to third ring gear 32 through sixth shaft 76, and then to output shaft 52 through third planetary carrier 31.

[0065] Eighth forward gear: Close the brake 60, the third clutch 63 and the fourth clutch 64; release the first clutch 61 and the second clutch 62.

[0066] Power is input from the input shaft 51. Because the brake 60 is closed, the first shaft 71 is stationary. Power is transmitted from the second ring gear 22 of the second planetary gear assembly P2 to the third planetary gear assembly P3. The third clutch 63 and the fourth clutch 64 are closed, and power is transmitted to the output shaft 52 through the planet carrier of the third planetary gear assembly P3.

[0067] Reverse (R): Close the brake 60, the first clutch 61 and the third clutch 63; release the second clutch 62 and the fourth clutch 64.

[0068] Power is input through the input shaft 51. Because the brake 60 and the first clutch 61 are closed, the eighth shaft 78 and the first shaft 71 do not rotate. Power is transmitted from the second ring gear 22 of the second planetary gear assembly P2 to the third planetary gear assembly P3, and then from the third planet carrier 31 of the third planetary gear assembly P3 to the output shaft 52.

[0069] The first sun gear 10 and the second sun gear 20 of this application adopt a left-handed design, while the third sun gear 30 and the fourth sun gear 40 adopt a right-handed design. Taking the second forward gear as an example, the stress analysis of the corresponding components is as follows:

[0070] When the car is in second forward gear, brake 60, first clutch 61, and fourth clutch 64 are engaged; second clutch 62 and third clutch 63 are disengaged. Figure 1As shown, during transmission operation, the input shaft 51 rotates, driving the second planetary carrier 21 to rotate. Since the second sun gear 20 remains stationary, the second planetary carrier 21 drives the second ring gear 22 to rotate. The second ring gear 22 is connected to the third sun gear 30, and because the fourth clutch 64 is engaged, the third planetary gear assembly P3 is integrated, meaning the third sun gear 30, the third planetary carrier 31, and the third ring gear 32 all rotate at the same speed. The third ring gear 32 drives the fourth sun gear 40 to rotate. Because the brake 60 and the first clutch 61 are engaged, the fourth ring gear 42 does not rotate, thus driving the fourth planetary carrier 41 to rotate via the fourth sun gear 40.

[0071] The second gear is a forward gear; therefore, both the input shaft 51 and the output shaft 52 rotate clockwise. Clockwise rotation here refers to the direction of rotation of the input shaft 51 and output shaft 52 when viewed from the output end of the transmission towards the input end. Since the fourth clutch 64 is engaged, the fourth planetary gear set P4 initiates power transmission. Because the fourth sun gear 40 has a right-handed design, it transmits axial force to the left. The force on the fourth sun gear 40 is to the left; therefore, the bearings on the right side of the fourth sun gear 40 and the bearings on the right side of the fourth planetary carrier 41 are not subjected to force. The axial force is transmitted to the left through the fourth sun gear 40, and then through the spline and the inner hub of the corresponding clutch to the third sun gear 30, causing the third sun gear 30 to experience a leftward force. Bearings are located adjacent to the spline and between the inner hub. On the other hand, the input shaft 51 drives the second planetary carrier 21 to rotate. Since the second sun gear 20 adopts a left-handed design, the axial force on the second sun gear 20 is to the right. As is well known, in a planetary gear set, the axial forces on the sun gear and the ring gear are in opposite directions, and the axial force on the planetary carrier is canceled out. Therefore, the force on the second ring gear 22 is to the left. The third sun gear 30 is connected to the second ring gear 22, so the axial force on the third sun gear 30 is to the left, which in turn causes the axial force on the third ring gear 32 to be to the right. The third ring gear 32 is connected to the fourth sun gear 40, so the axial force exerted by the third ring gear 32 on the fourth sun gear 40 is to the right, which cancels out part of the axial force on the fourth sun gear 40 to the left, thereby reducing the force on each bearing between the third sun gear 30 and the fourth sun gear 40.

[0072] During operation, power flows through the third planetary gear set P3, causing it to generate a force that balances the output of the fourth sun gear 40. This reduces the stress on the bearings between the third and fourth planetary gear sets P3 and P4. Furthermore, the bearings near the output shaft 52 experience significant stress throughout the transmission. Therefore, this design effectively reduces the stress on these bearings, thereby lowering the bearing damage rate.

[0073] Among them, the left and right directions mentioned above are relative to the attached... Figure 1 Specifically, to the left is towards the input end of the transmission, and to the right is towards the output end. Furthermore, in existing transmissions, the axial connections of all rotating components are via bearings, allowing relative rotation between adjacent rotating components and providing axial support and force transmission. This connection method is common knowledge to those skilled in the art; therefore, the bearing positions disclosed herein are obvious to those skilled in the art and have not been described in detail.

[0074] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low-speed, heavy-duty, longitudinally mounted transmission, characterized in that, include: Housing, input shaft, output shaft, first planetary gear assembly, second planetary gear assembly, third planetary gear assembly, fourth planetary gear assembly, first clutch, second clutch, third clutch, and fourth clutch; The first planetary gear set includes a first sun gear, a first planetary gear, a first planet carrier, and a first ring gear; the second planetary gear set includes a second sun gear, a second planetary gear, a second planet carrier, and a second ring gear; the third planetary gear set includes a third sun gear, a third planetary gear, a third planet carrier, and a third ring gear; the fourth planetary gear set includes a fourth sun gear, a fourth planetary gear, a fourth planet carrier, and a fourth ring gear. The input shaft is connected to the second clutch and the second planetary carrier, respectively. The first planetary carrier is connected to the first clutch via a second rotating shaft, the first gear ring is fixedly mounted on the inner wall of the housing, and the first sun gear is connected to the inner wall of the housing; The second gear ring is connected to the third sun gear via a third rotating shaft; The third rotating shaft is connected to the fourth rotating shaft via the fifth rotating shaft, the fourth clutch is disposed on the fifth rotating shaft, and the third planetary carrier is connected to the third clutch via the fourth rotating shaft; The third gear ring is connected to the second clutch via the sixth rotating shaft; The fourth sun gear is connected to the sixth shaft, the fourth planetary carrier is connected to the third clutch via the seventh shaft, and the output shaft is connected to the fourth planetary carrier via a transmission. The fourth gear ring is connected to the first clutch via the eighth rotating shaft.

2. The low-speed, heavy-duty, longitudinally mounted transmission according to claim 1, characterized in that, The output shaft is connected to the seventh shaft mounted on the fourth planetary carrier.

3. The low-speed, heavy-duty longitudinally mounted transmission according to claim 1, characterized in that, The input shaft and the output shaft are coaxially arranged.

4. The low-speed, heavy-duty longitudinally mounted transmission according to claim 3, characterized in that, The first planetary gear set, the second planetary gear set, the third planetary gear set, and the fourth planetary gear set are arranged sequentially along the axial direction of the output shaft.

5. The low-speed, heavy-duty longitudinally mounted transmission according to claim 1, characterized in that, It also includes brakes; The brake is fixedly installed on the inner wall of the housing, and the brake is connected to the first sun gear and the second sun gear respectively through the first rotating shaft.

6. The low-speed, heavy-duty longitudinally mounted transmission according to claim 5, characterized in that, It also includes a hydraulic assembly connected to the brake, the first clutch, the second clutch, the third clutch and the fourth clutch respectively, the hydraulic assembly being used to provide oil pressure to the brake, the first clutch, the second clutch, the third clutch and the fourth clutch.

7. The low-speed, heavy-duty longitudinally mounted transmission according to claim 5, characterized in that, The low-speed, heavy-duty, longitudinally mounted transmission includes eight forward gears and one reverse gear: The first forward gear is achieved by closing the brake, the first clutch, and the second clutch; The second forward gear is achieved by closing the brake, the first clutch, and the fourth clutch; The third forward gear is achieved by engaging the first clutch, the second clutch, and the fourth clutch; The fourth forward gear is achieved by engaging the first clutch, the third clutch, and the fourth clutch; The fifth forward gear is achieved by engaging the first clutch, the second clutch, and the third clutch; The sixth forward gear is achieved by engaging the second clutch, the third clutch, and the fourth clutch; The seventh forward gear is achieved by closing the brake, the second clutch, and the third clutch; The eighth forward gear is achieved by closing the brake, the third clutch, and the fourth clutch; Reverse gear is achieved by closing the brake, the first clutch, and the third clutch.

8. The low-speed, heavy-duty longitudinally mounted transmission according to claim 1, characterized in that, It also includes a hydraulic torque converter disposed within the housing, one end of which is connected to the engine and the other end of which is connected to the input shaft.

Images