Hydraulic-mechanical continuously variable transmission for heavy construction vehicles

Abstract

The application discloses a kind of heavy engineering vehicle hydraulic mechanical compound continuously variable transmission, the continuously variable transmission includes input mechanism, hydraulic speed regulation loop, power coupling mechanism, shift mechanism and output mechanism;Three planetary rows are used as power coupling mechanism, the compound of hydraulic speed regulation loop and mechanical loop is carried out, and only partial power is transmitted in hydraulic road, high transmission efficiency and stepless speed regulation are realized.Compared with the traditional heavy engineering vehicle gearbox, the above continuously variable transmission uses small-power hydraulic components to realize high-power transmission, does not need to customize transmission components, is conducive to reducing research and development cost, can greatly improve transmission efficiency, and can make engine work in economic speed interval, reduce the oil consumption and noise level of heavy engineering vehicle.

Description

Technical Field

[0001] This invention belongs to the field of power transmission technology, specifically relating to a hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles, suitable for applications such as high-power loaders of 10 tons or more and heavy-duty tracked tractors of 400 to 600 horsepower. Background Technology

[0002] Currently, heavy-duty off-road engineering vehicles such as large loaders with engine power exceeding 500 horsepower generally employ hydraulic transmission systems, which suffer from low transmission efficiency and significant power loss. Due to low sales volume, these transmission systems are primarily imported. With the development of agricultural technology, domestic demand for heavy-duty tractors is gradually increasing. However, due to the lack of corresponding transmission systems, the 400-600 horsepower heavy-duty tracked tractor market is largely monopolized by foreign brands.

[0003] Hydraulic-mechanical composite continuously variable transmissions (CVTs) combine mechanical and hydraulic power to achieve highly efficient continuously variable transmission, maintaining stable engine load and improving fuel economy, making them one of the development directions for engineering vehicle transmission systems. Transmission giant ZF has developed a series of hydraulic-mechanical CVT devices for heavy-duty engineering vehicles, with a maximum power exceeding 600 horsepower.

[0004] The components of high-power, high-efficiency transmission devices for existing heavy engineering vehicles need to be custom-developed, which is costly and time-consuming. Summary of the Invention

[0005] This invention provides a hydraulic-mechanical composite continuously variable transmission device for heavy-duty engineering vehicles. This continuously variable transmission device is suitable for heavy-duty engineering vehicles, uses low-power hydraulic components to achieve high-power transmission, eliminates the need for customized transmission parts, and helps reduce R&D costs. It includes four different working sections to adapt to various working conditions of heavy-duty engineering vehicles. Each working section has continuous speed change, the speed of the hydraulic components changes continuously, the clutch switches without speed difference, the operation is simple, the transmission efficiency is high, the required power of the hydraulic components is small, and it has high transmission efficiency for both low-speed operation and high-speed driving. It can significantly improve the transmission efficiency of the transmission device and allow the engine to operate in the economic speed range, reducing the fuel consumption and noise level of heavy-duty engineering vehicles.

[0006] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0007] A hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles, comprising an input mechanism, a hydraulic speed regulating circuit, a power coupling mechanism, a shifting mechanism, and an output mechanism;

[0008] The input mechanism includes an input shaft, a first gear, a second gear, a third gear, a first shaft, a second shaft, and a fourth gear, used to connect to the engine to input power;

[0009] The hydraulic speed control circuit includes a bidirectional variable pump, a fixed displacement motor, and a replenishing pump. The bidirectional variable pump and the fixed displacement motor form a closed hydraulic circuit. The replenishing pump maintains the low pressure of the closed hydraulic circuit and provides control oil pressure for the bidirectional variable pump and the fixed displacement motor.

[0010] The power coupling mechanism consists of three planetary gear sets, including a sun gear shaft, a first sun gear, a first planet carrier, a first ring gear, a first ring gear 1, a first gear, a first ring gear 2, a first planet carrier gear, a second sun gear, a second planet carrier, a second ring gear, a third sun gear, a third planet carrier, a third ring gear, a third ring gear, and a third planet carrier gear. Mechanical power is input from the first planet carrier and the second ring gear via the input mechanism through the first planet carrier gear, while hydraulic power is input from the sun gear shaft via the fixed displacement motor. The power coupling mechanism is used to couple mechanical power and hydraulic power before outputting them.

[0011] The shifting mechanism includes a first clutch C1, a second clutch C2, a third clutch C3, a fourth clutch C4, a fifth gear, a sixth gear, a third shaft (11), a seventh gear, an eighth gear, a ninth gear, a fourth shaft, and a tenth gear, which are used to switch between four working stages and to transmit the power of the power coupling mechanism to the output mechanism.

[0012] The output mechanism consists of a forward / reverse output mechanism and a PTO mechanism, including a forward gear clutch CV, a reverse gear clutch CR, a CPTO clutch, an eleventh gear, a fourth planetary carrier, a fifth planetary carrier, an output shaft sun gear, an output shaft, a twelfth gear, and a PTO output shaft, used to output power.

[0013] Furthermore, the first gear and the second gear are fixedly mounted on the input shaft; the first gear meshes with the twelfth gear to transmit the input power to the PTO output shaft;

[0014] The second gear meshes with the third gear and the first planetary carrier gear to transmit input power to the hydraulic speed control circuit and the power coupling mechanism.

[0015] Furthermore, the driving end of the CPTO clutch is fixedly connected to the twelfth gear, and the driven end is fixedly mounted on the PTO output shaft.

[0016] Furthermore, the third gear meshes with the fourth gear; the fourth gear is fixedly mounted on the second shaft;

[0017] The bidirectional variable pump is arranged coaxially with the second shaft;

[0018] The quantitative motor is arranged coaxially with the sun gear shaft.

[0019] Furthermore, the first sun gear, the second sun gear, and the third sun gear are all fixedly mounted on the sun gear shaft;

[0020] The first planetary carrier is fixedly connected to the second gear ring, and the first planetary carrier gear is fixedly installed thereon;

[0021] Both the first gear ring gear one and the first gear ring gear two are fixedly installed on the first gear ring.

[0022] The second planetary carrier is fixedly connected to the third gear ring, and the third gear ring gear is also fixedly connected thereto.

[0023] The third planetary carrier gear is fixedly connected to the third planetary carrier;

[0024] Power is coupled through three planetary gear sets and then transmitted to the first stage clutch C1 via the third planetary carrier gear, to the second stage clutch C2 via the first ring gear, to the third stage clutch C3 via the third ring gear, and to the fourth stage clutch C4 via the first ring gear.

[0025] Furthermore, the driven end of the first clutch C1 is fixedly connected to the driven end of the fourth clutch C4, and is also fixedly connected to the tenth gear; the driving end of the first clutch C1 is fixedly connected to the eighth gear, which meshes with the third planetary carrier gear to transmit power from the power coupling mechanism; the tenth gear meshes with the eleventh gear.

[0026] The driving end of the fourth clutch C4 is fixedly connected to the ninth gear, which meshes with the first gear ring gear to transmit power from the power coupling mechanism.

[0027] The driven end of the second-stage clutch C2 is fixedly connected to the driven end of the third-stage clutch C3, and is also fixedly connected to the seventh gear; the driving end of the second-stage clutch C2 is fixedly connected to the sixth gear, which meshes with the first gear ring gear to transmit power from the power coupling mechanism; the seventh gear meshes with the eleventh gear.

[0028] The fifth gear is fixedly connected to the driving end of the third stage clutch C3. The fifth gear meshes with the third gear ring gear to transmit power from the power coupling mechanism.

[0029] When the forward gear clutch CV is engaged, the three planetary gear sets rotate as a whole, and the sun gear on the output shaft outputs power.

[0030] When the reverse clutch CR is engaged, the fourth planetary carrier and the fifth planetary carrier receive power, and the sun gear on the output shaft outputs power.

[0031] Furthermore, the eleventh gear is loosely fitted onto the output shaft; the sun gear of the output shaft is fixedly mounted on the output shaft; both the fourth planet carrier and the fifth planet carrier are fixedly connected to the eleventh gear; the fifth planet carrier meshes with the sun gear of the output shaft; and the fourth planet carrier meshes with the output ring gear.

[0032] The driving end of the forward gear clutch CV is fixedly connected to the output gear ring, and the driven end is fixedly connected to the output shaft;

[0033] The driving end of the reverse clutch CR is the braking end, and the driven end is fixedly connected to the output gear ring. When the reverse clutch CR is engaged, the output gear ring brakes.

[0034] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0035] 1. The continuously variable transmission (CVT) of this invention is suitable for heavy-duty engineering vehicles. It uses three planetary gear sets as power coupling mechanisms to combine hydraulic and mechanical power. It switches between four working sections through a shifting mechanism and forward / reverse gears through a forward / reverse gear mechanism. It adopts a four-section continuous design, with each of the four working sections being a hydraulic-mechanical composite transmission section. It provides stepless speed regulation throughout the entire process. The lower working section is used for starting and high-traction operation, and for low-speed driving and high-traction conditions. The higher working section is used for high-speed driving conditions. It can achieve a large transmission efficiency within each working section, realizing a wide range of stepless speed change. The vehicle can smoothly connect the various stages without interrupting the vehicle's power during forward and segment transitions, improving power performance, significantly improving the transmission efficiency of the transmission device, and enhancing the adaptability of engineering machinery to various working conditions.

[0036] 2. The continuously variable transmission (CVT) device of this invention employs a combination of hydraulic and mechanical power. The hydraulic circuit transmits only a portion of the power, while the majority is transmitted through the mechanical circuit, achieving high transmission efficiency and continuously variable speed. This improves operational efficiency, reduces engine fuel consumption, enhances vehicle maneuverability, and increases vehicle load capacity. Gear shifting is achieved via a wet clutch. Due to the hydraulic speed control system, power shifting is possible; the clutch for the next gear is engaged before disengaging the clutch for the previous gear, ensuring uninterrupted power output and improving operational efficiency.

[0037] 3. The continuously variable transmission device of this invention uses low-power hydraulic components to achieve high-power transmission without the need for customized transmission parts, which helps reduce R&D costs. Each working section features continuous speed change, with the hydraulic components' speed changing continuously. The clutch switches without speed difference, making operation simple, transmission efficiency high, and requiring relatively low-power hydraulic components that are readily available on the civilian market. Attached Figure Description

[0038] Figure 1 This is a simplified transmission diagram of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention;

[0039] Figure 2 This is a simplified transmission diagram of the power coupling mechanism;

[0040] Figure 3 This is a speed lever diagram of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention;

[0041] Figure 4 This is a diagram showing the motor speed control of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention.

[0042] Figure 5 This is a diagram showing the motor working pressure of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention.

[0043] Figure 6 This is a diagram showing the output torque of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention.

[0044] Figure 7 This is a diagram showing the output traction force of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention.

[0045] Figure 8 This is a diagram showing the transmission efficiency of the hydraulic mechanical composite continuously variable transmission device for heavy engineering vehicles according to the present invention.

[0046] Wherein, 1-input shaft, 2-first gear, 3-second gear, 4-third gear, 5-first shaft, 6-power coupling mechanism, 7-fifth gear, 8-sixth gear, 9-third-stage clutch C3, 10-second-stage clutch C2, 11-third shaft, 12-seventh gear, 13-eighth gear, 14-ninth gear, 15-first-stage clutch C1, 16-fourth-stage clutch C4, 17-tenth gear, 18-fourth shaft, 19-eleventh gear, 20-reverse clutch CR, 21-fourth planetary carrier, 22-forward clutch CV, 23-fifth planetary carrier, 24-output shaft sun gear, 25-output shaft, 26-second shaft 27-Fourth gear, 28-Twelfth gear, 29-CPTO clutch, 30-PTO output shaft, 31-Bidirectional variable pump, 32-Fixed displacement motor, 33-Maintenance pump, 34-Output ring gear, 610-Sun gear shaft, 611-First sun gear, 612-First planetary carrier, 613-First ring gear, 614-First ring gear one, 615-First ring gear two, 616-First planetary carrier gear, 621-Second sun gear, 622-Second planetary carrier, 623-Second ring gear, 631-Third sun gear, 632-Third planetary carrier, 633-Third ring gear, 634-Third ring gear, 635-Third planetary carrier gear. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] like Figure 1 As shown in the structure, this embodiment provides a hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles. The continuously variable transmission device includes an input mechanism, a hydraulic speed regulation circuit, a power coupling mechanism 6, a shifting mechanism, and an output mechanism.

[0049] The input mechanism includes an input shaft 1, a first gear 2, a second gear 3, a third gear 4, a first shaft 5, a second shaft 26, and a fourth gear 27, for connecting to the engine to input power; the first gear 2 and the second gear 3 are fixedly mounted on the input shaft 1; the first gear 2 meshes with the twelfth gear 28 for transmitting the input power to the PTO output shaft 25; the second gear 3 meshes with the third gear 4 and the first planetary carrier gear 616 for transmitting the input power to the hydraulic speed control circuit and the power coupling mechanism 6; the third gear 4 meshes with the fourth gear 27; the fourth gear 27 is fixedly mounted on the second shaft 26.

[0050] The hydraulic speed control circuit includes a bidirectional variable pump 31, a fixed displacement motor 32, and a replenishing pump 33. The bidirectional variable pump 31 and the fixed displacement motor 32 form a closed hydraulic circuit. The replenishing pump 33 maintains the low pressure of the closed hydraulic circuit and provides control oil pressure for the bidirectional variable pump 31 and the fixed displacement motor 32. The bidirectional variable pump 31 is coaxially arranged with the second shaft 26. The fixed displacement motor 32 is coaxially arranged with the sun gear shaft 610 of the power coupling mechanism 6.

[0051] like Figure 1 and Figure 2 As shown, the power coupling mechanism 6 consists of three planetary gear sets and includes a sun gear shaft 610, a first sun gear 611, a first planet carrier 612, a first ring gear 613, a first ring gear 614, a first ring gear 615, a first planet carrier gear 616, a second sun gear 621, a second planet carrier 622, a second ring gear 623, a third sun gear 631, a third planet carrier 632, a third ring gear 633, a third ring gear 634, and a third planet carrier gear 635; the three planetary gear sets are... The planetary gears are designated as first planetary gear set k1, second planetary gear set k2, and third planetary gear set k3. Mechanical power is input via the input mechanism through the first planetary carrier gear 616 from the first planetary carrier 612 and the second ring gear 623. Hydraulic power is input via the fixed displacement motor 32 from the sun gear shaft 610. The power coupling mechanism 6 couples the mechanical and hydraulic power before outputting them. The first sun gear 611, second sun gear 621, and third sun gear 631 are all fixedly mounted on the sun gear shaft 610. The first planetary carrier 612 and the second planetary gear set k3 are connected to the first planetary carrier gear 612 and the third planetary carrier gear 623. The second planetary carrier 623 is fixedly connected to and has a first planetary carrier gear 616 fixedly mounted on it; the first planetary carrier gear 616 rotates synchronously with the first planetary carrier 612; the first ring gear 614 and the first ring gear 615 are both fixedly mounted on the first ring gear 613, and the first ring gear 614 and the first ring gear 615 rotate synchronously with the first ring gear 613; the second planetary carrier 622 is fixedly connected to the third ring gear 633, and has a third ring gear 634 fixedly connected to it; the third ring gear 634 and... The third ring gear 633 rotates synchronously; the third planetary carrier gear 635 is fixedly connected to the third planetary carrier 632, and the third planetary carrier gear 635 and the third planetary carrier 632 rotate synchronously; the power is coupled through the three planetary gear sets and then transmitted through the third planetary carrier gear 635 to the first clutch C115, through the second ring gear 615 to the second clutch C210, through the third ring gear 634 to the third clutch C39, and through the first ring gear 614 to the fourth clutch C416.

[0052] The gear shifting mechanism includes a first-stage clutch C115, a second-stage clutch C210, a third-stage clutch C39, a fourth-stage clutch C416, a fifth gear 7, a sixth gear 8, a third shaft 11, a seventh gear 12, an eighth gear 13, a ninth gear 14, a fourth shaft 18, and a tenth gear 17, used to switch between four working stages and transmit the power of the power coupling mechanism 6 to the output mechanism; the driven end of the first-stage clutch C115 is fixedly connected to the driven end of the fourth-stage clutch C416, and the tenth gear 17 is also fixedly connected thereto; The driving end of the first clutch C115 is fixedly connected to the eighth gear 13, which is coaxially arranged with the first clutch C115. The eighth gear 13 meshes with the third planetary carrier gear 635 and transmits power from the power coupling mechanism 6. The tenth gear 17 meshes with the eleventh gear 19. The driving end of the fourth clutch C416 is fixedly connected to the ninth gear 14, which is coaxially arranged with the fourth clutch C416. The ninth gear 14 meshes with the first gear ring gear 614 and transmits power from the power coupling mechanism 6. The driven end of the second-stage clutch C210 and the driven end of the third-stage clutch C39 are fixedly connected, and a seventh gear 12 is also fixedly connected thereto. The driving end of the second-stage clutch C210 is fixedly connected to a sixth gear 8, which meshes with a first gear ring 615 to transmit power from the power coupling mechanism 6. The seventh gear 12 meshes with an eleventh gear 19. The driving end of the third-stage clutch C39 is fixedly connected to a fifth gear 7, which is coaxially arranged with the third-stage clutch C39. The fifth gear 7 meshes with a third gear ring 634 to transmit power from the power coupling mechanism 6.

[0053] The output mechanism consists of a forward / reverse output mechanism and a PTO mechanism, including a forward clutch CV22, a reverse clutch CR20, a PTO clutch 29, an eleventh gear 19, a fourth planetary carrier 21, a fifth planetary carrier 23, an output shaft sun gear 24, an output shaft 25, a twelfth gear 28, and a PTO output shaft 25, used for outputting power. The input shaft 1, first shaft 5, output shaft 25, second shaft 26, and sun gear shaft 610 are arranged in parallel. The driving end of the PTO clutch 29 is fixedly connected to the twelfth gear 28, and the driven end is fixedly mounted on the PTO output shaft 25. When the forward clutch CV22 is engaged, the three planetary gear sets rotate as a whole, and the output shaft sun gear 24 outputs power; when the reverse clutch CR20 is engaged, the fourth planetary carrier 21 and the fifth planetary carrier 23 input power, and the output shaft sun gear 24 outputs power. Eleventh gear 19 is loosely fitted onto output shaft 25; output shaft sun gear 24 is fixedly mounted on output shaft 25; fourth planetary carrier 21 and fifth planetary carrier 23 are both fixedly connected to eleventh gear 19; fifth planetary carrier 23 meshes with output shaft sun gear 24; fourth planetary carrier 21 meshes with output ring gear 34; the driving end of forward gear clutch CV22 is fixedly connected to output ring gear 34, and the driven end is fixedly connected to output shaft 25; the driving end of reverse gear clutch CR20 is the braking end, and the driven end is fixedly connected to output ring gear 34. When reverse gear clutch CR20 is engaged, output ring gear 34 brakes.

[0054] The switching logic of the continuously variable transmission device described above is shown in Table 1 below.

[0055] Table 1. Switching Logic of the Continuously Variable Transmission System

[0056]

[0057] Taking the forward movement of a heavy engineering vehicle as an example, the working principle of the four working sections of the continuously variable transmission device described above is explained. All four working sections are hydraulic-mechanical composite transmission sections, namely the first section, the second section, the third section, and the fourth section.

[0058] In the first stage, the first-stage clutch C115 engages with the forward gear clutch CV22, while the second-stage clutch C210, third-stage clutch C39, fourth-stage clutch C416, and reverse gear clutch CR20 disengage, allowing the continuously variable transmission (CVT) to enter the first transmission stage of forward gear. Engine power is transmitted to the CVT via input shaft 1, where it is split into hydraulic and mechanical power. The hydraulic power is transmitted to the hydraulic speed control circuit via the second gear 3, third gear 4, and fourth gear 27, and then via the bidirectional variable pump 31, fixed displacement motor 32, and sun gear shaft 610 to the power coupling mechanism 6. The mechanical power is transmitted to the power coupling mechanism 6 via the second gear 3 and first gear ring 613, where it is coupled with the hydraulic power from the hydraulic speed control circuit. After power coupling, the output is transmitted to the forward / reverse gear output mechanism via the third planetary carrier gear 635, eighth gear 13, first-stage clutch C115, and tenth gear 17, and then output via the eleventh gear 19, fourth planetary carrier 21, forward gear clutch CV22, and output shaft 25.

[0059] In the second stage, the second-stage clutch C210 engages with the forward gear clutch CV22, while the first-stage clutch C115, the third-stage clutch C39, the fourth-stage clutch C416, and the reverse gear clutch CR20 disengage. The transmission then enters the second forward gear transmission stage. The input, splitting, and coupling process of engine power is consistent with the first transmission stage. After power coupling in the second transmission stage, the output is via the first ring gear 615, then through the sixth gear 8, the second-stage clutch C210, and the seventh gear 12 to the forward and reverse gear output mechanism. Finally, the output is transmitted through the eleventh gear 19, the fourth planetary carrier 21, the forward gear clutch CV22, and the output shaft 25.

[0060] In the third stage, the third-stage clutch C39 engages with the forward gear clutch CV22, while the first-stage clutch C115, the second-stage clutch C210, the fourth-stage clutch C416, and the reverse gear clutch CR20 disengage, and the transmission enters the third forward gear transmission stage. The input, splitting, and coupling process of engine power is consistent with the first transmission stage. After power coupling in the third transmission stage, it is output through the third ring gear 634, then through the fifth gear 7, the third-stage clutch C39, and the seventh gear 12 to the forward and reverse gear output mechanism. Finally, it is output through the eleventh gear 19, the fourth planetary carrier 21, the forward gear clutch CV22, and the output shaft 25.

[0061] In the fourth stage, the fourth-stage clutch C416 engages with the forward gear clutch CV22, while the first-stage clutch C115, second-stage clutch C210, third-stage clutch C39, and reverse gear clutch CR20 disengage. The transmission then enters the fourth forward gear transmission stage. The input, splitting, and coupling process of engine power is consistent with the first transmission stage. After power coupling in the fourth transmission stage, the output is via the first ring gear 614, then through the seventh gear 12, the fourth-stage clutch C416, and the tenth gear 17 to the forward / reverse gear output mechanism. Finally, the output is transmitted through the eleventh gear 19, the fourth planetary carrier 21, the forward gear clutch CV22, and the output shaft 25.

[0062] Like the forward gears, reverse gear also has four operating stages. When the reverse clutch CR20 engages and the forward clutch CV22 disengages, the continuously variable transmission (CVT) enters reverse gear. The other clutches engage and disengage according to the different operating stages. The power transmission route in reverse gear is basically the same as in forward gear, except that the power output goes through the eleventh gear 19, the fifth planetary carrier 23, the sun gear 24 on the output shaft, and the output shaft 25.

[0063] Figure 3 This is a speed lever diagram of the hydraulic mechanical composite continuously variable transmission device for heavy engineering vehicles of the present invention. The five lever nodes in the diagram represent different components of the power coupling mechanism, which intuitively shows the rotational speed relationship inside the power coupling mechanism. When the input speed and motor speed are determined, four output speeds can be determined according to the lever principle. The final output speed of the power coupling mechanism is determined according to the different working sections.

[0064] Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The main dynamic characteristics of the hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles of the present invention are shown, demonstrating the changes in the dynamic characteristics of some core components of the present invention with the speed of heavy engineering vehicles, such as: motor speed, output speed, motor pressure difference, traction force, output torque, transmission efficiency, etc. The components of the present invention can meet all the required working conditions, and the dynamic characteristics are reasonable, indicating the feasibility of the structural and parameter design of the present invention.

[0065] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A hydraulic-mechanical composite continuously variable transmission device for heavy engineering vehicles, characterized in that, It includes an input mechanism, a hydraulic speed control circuit, a power coupling mechanism (6), a gear shifting mechanism, and an output mechanism; The input mechanism includes an input shaft (1), a first gear (2), a second gear (3), a third gear (4), a first shaft (5), a second shaft (26), and a fourth gear (27), which are used to connect to the engine to input power; The hydraulic speed control circuit includes a bidirectional variable pump (31), a fixed displacement motor (32), and a replenishing pump (33). The bidirectional variable pump and the fixed displacement motor form a closed hydraulic circuit. The replenishing pump maintains the low pressure of the closed hydraulic circuit and provides control oil pressure for the bidirectional variable pump and the fixed displacement motor. The power coupling mechanism consists of three planetary gear sets, including a sun gear shaft, a first sun gear, a first planet carrier, a first ring gear, a first ring gear 1, a first gear, a first ring gear 2, a first planet carrier gear, a second sun gear, a second planet carrier, a second ring gear, a third sun gear, a third planet carrier, a third ring gear, a third ring gear, and a third planet carrier gear. Mechanical power is input from the first planet carrier and the second ring gear via the input mechanism through the first planet carrier gear, while hydraulic power is input from the sun gear shaft via the fixed displacement motor. The power coupling mechanism is used to couple mechanical power and hydraulic power before outputting them. The shifting mechanism includes a first clutch C1 (15), a second clutch C2 (10), a third clutch C3 (9), a fourth clutch C4 (16), a fifth gear (7), a sixth gear (8), a third shaft (11), a seventh gear (12), an eighth gear (13), a ninth gear (14), a fourth shaft (18), and a tenth gear (17), which are used to switch between the four gears and transmit the power of the power coupling mechanism to the output mechanism. The output mechanism consists of a forward / reverse output mechanism and a PTO mechanism, including a forward gear clutch CV (22), a reverse gear clutch CR (20), a CPTO clutch (29), an eleventh gear (19), a fourth planetary carrier (21), a fifth planetary carrier (23), an output shaft sun gear (24), an output shaft (25), a twelfth gear (28), an output gear ring (34), and a PTO output shaft (30), used to output power; The first gear and the second gear are fixedly mounted on the input shaft; The first gear meshes with the twelfth gear to transmit input power to the PTO output shaft; The second gear meshes with the third gear and the first planetary carrier gear to transmit input power to the hydraulic speed control circuit and the power coupling mechanism; The driving end of the CPTO clutch is fixedly connected to the twelfth gear, and the driven end is fixedly installed on the PTO output shaft. The third gear meshes with the fourth gear; the fourth gear is fixedly mounted on the second shaft; The bidirectional variable pump is coaxially connected to the second shaft; The quantitative motor is coaxially connected to the sun gear shaft; The first sun gear, the second sun gear, and the third sun gear are all fixedly mounted on the sun gear shaft; The first planetary carrier is fixedly connected to the second gear ring, and the first planetary carrier gear is fixedly installed thereon; Both the first gear ring gear one and the first gear ring gear two are fixedly installed on the first gear ring. The second planetary carrier is fixedly connected to the third gear ring, and the third gear ring gear is also fixedly connected thereto. The third planetary carrier gear is fixedly connected to the third planetary carrier; Power is coupled through three planetary gear sets and then transmitted to the first stage clutch C1 via the third planetary carrier gear, to the second stage clutch C2 via the first ring gear, to the third stage clutch C3 via the third ring gear, and to the fourth stage clutch C4 via the first ring gear. The driven end of the first clutch C1 is fixedly connected to the driven end of the fourth clutch C4, and is also fixedly connected to the tenth gear; the driving end of the first clutch C1 is fixedly connected to the eighth gear, which meshes with the third planetary carrier gear to transmit power from the power coupling mechanism; the tenth gear meshes with the eleventh gear. The driving end of the fourth clutch C4 is fixedly connected to the ninth gear, which meshes with the first gear ring gear to transmit power from the power coupling mechanism. The driven end of the second-stage clutch C2 is fixedly connected to the driven end of the third-stage clutch C3, and is also fixedly connected to the seventh gear; the driving end of the second-stage clutch C2 is fixedly connected to the sixth gear, which meshes with the first gear ring gear to transmit power from the power coupling mechanism; the seventh gear meshes with the eleventh gear. The fifth gear is fixedly connected to the driving end of the third stage clutch C3. The fifth gear meshes with the third gear ring gear to transmit power from the power coupling mechanism. The eleventh gear is loosely fitted onto the output shaft; the sun gear of the output shaft is fixedly mounted on the output shaft; both the fourth planet carrier and the fifth planet carrier are fixedly connected to the eleventh gear; the fifth planet carrier meshes with the sun gear of the output shaft; the fourth planet carrier meshes with the output ring gear. The driving end of the forward gear clutch CV is fixedly connected to the output gear ring, and the driven end is fixedly connected to the output shaft; The driving end of the reverse clutch CR is the braking end, and the driven end is fixedly connected to the output gear ring. When the reverse clutch CR is engaged, the output gear ring brakes.

2. The transmission device as described in claim 1, characterized in that, When the forward gear clutch CV is engaged, the three planetary gear sets rotate as a whole, and the sun gear on the output shaft outputs power. When the reverse clutch CR is engaged, the fourth planetary carrier and the fifth planetary carrier receive power, and the sun gear on the output shaft outputs power.

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