Continuously variable transmission and wheeled machine

Abstract

The application relates to a continuously variable transmission mechanism and a wheeled machine in the technical field of transmission. The continuously variable transmission mechanism comprises a planetary gear transmission system, a driving mechanism and a hydraulic closed system. The planetary gear transmission system comprises an internal gear, a sun gear and a planet carrier. The driving mechanism is in transmission connection with the planet carrier. The hydraulic closed system is coupled with the internal gear and the sun gear, and converts the power of the internal gear and the sun gear into low-speed section output or high-speed section output. A clutch system is used for switching to the low-speed section or the high-speed section. An output shaft is connected with the clutch system. The continuously variable transmission mechanism increases the speed regulation range, and the speed regulation process from 0 speed to the maximum working speed does not need to switch the clutch. The transmission efficiency of the starting stage gearbox is high, and the service life and working efficiency of each element are improved.

Description

Technical Field

[0001] This application relates to the field of transmission technology, and in particular to a continuously variable transmission mechanism and wheeled machinery. Background Technology

[0002] Currently, wheeled machinery, including agricultural and construction machinery, mostly uses manual shift gearboxes for their drive transmission. Some gearboxes have a hydraulic torque converter at the input to reduce shift shock. In addition, some equipment has begun to adopt a transmission scheme that achieves continuously variable transmission through mechanical-hydraulic coupling.

[0003] However, these manual transmission devices have drawbacks such as discontinuous speed ratios and discontinuous power transmission during the shifting process, which can lead to high fuel consumption, complex operation, and difficulty in achieving automatic control. Some mechanical hydraulic continuously variable transmission (CVT) solutions also have drawbacks such as complex structure and discontinuous power transmission during the shifting process. From 0 speed to the maximum operating speed, there are usually two or more shifting segments, and the transmission efficiency of the gearbox is very low during the starting phase. For operating scenarios with frequent starts, accelerations, decelerations, and stops, the overall transmission efficiency of the vehicle will be low, and frequent segment switching will affect the lifespan of components and operating efficiency. Summary of the Invention

[0004] In view of the problems existing in the background technology, this application provides a continuously variable transmission mechanism and wheeled machinery. This continuously variable transmission mechanism increases the speed range. The speed change process from 0 speed to the maximum working speed does not require switching the clutch. The transmission efficiency of the gearbox is high in the starting stage, which improves the life of each component and the working efficiency.

[0005] According to one aspect of the present invention, a continuously variable transmission mechanism is provided, comprising: a planetary gear transmission system including an internal gear, a sun gear, and a planet carrier, wherein a drive mechanism is drively connected to the planet carrier; a hydraulic closed system coupling the internal gear and the sun gear to convert the power of the internal gear and the sun gear into a low-speed output or a high-speed output; a clutch system for switching to the low-speed segment or the high-speed segment; and an output shaft connected to the clutch system.

[0006] In some embodiments of the present invention, the hydraulic closed system includes a variable pump and a variable motor, wherein the input shaft of the variable pump is connected to the sun gear via a first gear pair, and the output end of the variable motor is connected to the internal gear via a second gear pair.

[0007] In some embodiments of the present invention, the clutch system includes a first clutch and a second clutch, the output shaft is connected to the internal gear via the first clutch and a third gear pair, and the output shaft is connected to the sun gear via the second clutch and a fourth gear pair.

[0008] In some embodiments of the present invention, both the first clutch and the second clutch are jaw clutches.

[0009] In some embodiments of the present invention, both the first clutch and the second clutch are plate clutches.

[0010] In some embodiments of the present invention, both the first clutch and the second clutch are normally open.

[0011] In some embodiments of the present invention, the variable motor is a bent-shaft type.

[0012] In some embodiments of the present invention, the low-speed section includes a reversing low-speed section and a forward low-speed section, and the high-speed section is a forward high-speed section.

[0013] In some embodiments of the present invention, the maximum value of the forward low-speed section is greater than or equal to the maximum operating speed required by the vehicle.

[0014] According to another aspect of the present invention, a wheeled machine is provided, comprising the continuously variable transmission mechanism described above.

[0015] This application provides a continuously variable transmission (CVT) mechanism. This CVT mechanism uses a variable pump and a variable motor, both of which are variable elements, to couple the internal gear and the sun gear, achieving dual-variable composite speed regulation. This increases the speed range, allowing for speed changes from 0 speed to maximum operating speed without the need for clutch switching. During the forward drive phase, no circulating power is generated, resulting in high transmission efficiency, especially noticeable during start-up. Furthermore, from the maximum reverse speed to the maximum forward speed, the entire speed change process involves only one segment switch with zero differential switching, ensuring uninterrupted power transmission and improving operational efficiency. The planetary gear transmission mechanism features low rotational speeds for each component, facilitating high-reliability design and extending the lifespan of each component. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0017] Figure 1 This is a schematic diagram of the overall structure of the continuously variable transmission mechanism according to the embodiments of this application;

[0018] Figure 2 It is a graph showing the relationship between the rotational speed of each component and the vehicle speed.

[0019] The labels in the attached diagram are as follows:

[0020] 1. First gear pair; 2. Variable pump; 3. Variable motor; 4. Second gear pair; 5. Internal gear; 6. Planetary carrier; 7. Sun gear; 8. Third gear pair; 9. First clutch; 10. Second clutch; 11. Fourth gear pair; 12. Output shaft;

[0021] 51. Variable pump speed; 52. Output shaft speed; 53. Variable motor speed; 54. Internal gear speed; 55. Planetary carrier speed; 56. Sun gear speed. Detailed Implementation

[0022] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0023] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0024] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0025] This application discloses a continuously variable transmission mechanism. For example... Figure 1 As shown, the continuously variable transmission mechanism includes a planetary gear transmission system, a hydraulic closed system, a clutch system, and an output shaft 12.

[0026] Furthermore, the planetary gear transmission system includes an internal gear 5, a sun gear 7, planet gears, and a planet carrier 6. The planet gears rotate around the sun gear 7. The internal gear 5 meshes with the planet gears. The planet carrier 6 serves as the input end of the continuously variable transmission mechanism. The drive mechanism (engine) is connected to the planet carrier 6, and the drive mechanism directly causes the planet carrier 6 to rotate.

[0027] The hydraulic closed-loop system couples the internal gear 5 and the sun gear 7, converting the power from the internal gear 5 and the sun gear 7 into either low-speed or high-speed output. It should be noted that the hydraulic closed-loop system used in this embodiment consists entirely of variable displacement elements.

[0028] The output shaft 12 is connected to the clutch system. The output shaft 12 serves as the output end of the continuously variable transmission mechanism. The clutch system is used to switch the output shaft 12 to the low-speed range or the high-speed range after the hydraulic closed system converts the power of the internal gear 5 and the sun gear 7 into the low-speed range or the high-speed range output.

[0029] Furthermore, the low-speed section includes the reversing low-speed section and the forward low-speed section, and the high-speed section is the forward high-speed section; among them, the maximum value of the forward low-speed section is greater than or equal to the maximum operating speed required by the vehicle.

[0030] In some implementations, such as Figure 1 As shown, the hydraulic closed system includes a variable pump 2 and a variable motor 3. The input shaft of the variable pump 2 is connected to the sun gear 7 through a first gear pair 1, and the output end of the variable motor 3 is connected to the internal gear 5 through a second gear pair 4.

[0031] It is understandable that the start of the drive mechanism causes the planet carrier 6 and planet gears to rotate, which in turn causes the sun gear 7 to rotate. At this time, the speed of the sun gear 7 is in the same direction as the speed of the planet carrier 6. By changing the displacement of the variable motor 3 and / or the variable pump 2, and through the transmission of the first gear pair 1 and the second gear pair 4, the speed of the internal gear 5 and the sun gear 7 can be changed simultaneously.

[0032] It should be noted that the variable motor 3 in this embodiment is a bent shaft type; furthermore, the hydraulic closed system in this embodiment can also use an electric motor to replace the variable pump 2 and the variable motor 3, and the subsequent stepless speed regulation is achieved by electrodes to achieve electromechanical coupling stepless speed change.

[0033] In some implementations, such as Figure 1 As shown, the clutch system includes a first clutch 9 and a second clutch 10. The output shaft 12 is connected to the internal gear 5 through the first clutch 9 and the third gear pair 8, and the output shaft 12 is connected to the sun gear 7 through the second clutch 10 and the fourth gear pair 11.

[0034] Understandably, when the first clutch 9 is engaged and the second clutch 10 is disengaged, the internal gear 5 causes the output shaft 12 to rotate via the third gear pair 8. When the second clutch 10 is engaged and the first clutch 9 is disengaged, the sun gear 7 causes the output shaft 12 to rotate via the fourth gear pair 11. Specifically, in this embodiment, when the variable pump 2 and the variable motor 3 convert the power coupled between the internal gear 5 and the sun gear 7 into a low-speed reverse output or a low-speed forward output, the first clutch 9 is engaged and the second clutch 10 is disengaged; when the variable pump 2 and the variable motor 3 convert the power coupled between the internal gear 5 and the sun gear 7 into a high-speed forward output, the second clutch 10 is engaged and the first clutch 9 is disengaged.

[0035] Specifically, in this embodiment, both the first clutch 9 and the second clutch 10 are either dog clutches or plate clutches; dog clutches have lower power consumption, while plate clutches can reduce control difficulty; furthermore, both the first clutch 9 and the second clutch 10 are normally open.

[0036] like Figure 1 and Figure 2 As shown, the speed change process of the continuously variable transmission mechanism described above is as follows:

[0037] Figure 2 The horizontal axis represents vehicle speed, and the vertical axis represents the rotational speed of each component. Among them, 51 represents the relationship between the rotational speed of variable pump 2 and vehicle speed, 52 represents the relationship between the rotational speed of output shaft 12 and vehicle speed, 53 represents the relationship between the rotational speed of variable motor 3 and vehicle speed, 54 represents the relationship between the rotational speed of internal gear 5 and vehicle speed, 55 represents the relationship between the rotational speed of planetary carrier 6 and vehicle speed, and 56 represents the relationship between the rotational speed of sun gear 7 and vehicle speed.

[0038] Initially, the variable displacement motor 3 is at its maximum, the variable displacement pump 2 is at 0, and both the first clutch 9 and the second clutch 10 are disengaged. The engine starts and runs at its normal operating speed, driving the planetary carrier 6 to rotate. At this time, the internal gear 5 and the output shaft 12 both rotate at 0, and the sun gear 7 rotates in the same direction as the planetary carrier 6.

[0039] Based on the aforementioned initial state, combined with the first clutch 9, the displacement of the variable pump 2 is adjusted to gradually increase the speed of the variable motor 3 from zero to negative. At the same time, the speed of the internal gear 5 is gradually increased from zero to positive, and the speed of the sun gear 7 is gradually increased from the first set speed to negative. This causes the speed of the output shaft 12 to gradually increase from zero to negative until the speed of the output shaft 12 reaches the highest negative value. During this stage, the output shaft 12 will drive the entire vehicle to reverse until the reverse speed reaches the maximum reverse speed in the low-speed section of reversing.

[0040] Based on the aforementioned initial state, and in conjunction with the first clutch 9, the displacement of the variable pump 2 is adjusted to gradually increase the speed of the variable motor 3 from zero. At the same time, this causes the speed of the internal gear 5 to gradually increase from zero, and the speed of the sun gear 7 to gradually decrease from the first set speed. This causes the speed of the output shaft 12 to gradually increase from zero until the speed of the output shaft 12 reaches the highest value in the forward low-speed section. During this stage, the output shaft 12 will drive the entire vehicle forward until the vehicle's forward speed reaches the maximum forward speed in the forward low-speed section.

[0041] It should be noted that during the process of increasing the displacement of the variable pump 2 and decreasing the displacement of the variable motor 3 to continuously increase the vehicle's forward speed, the rotational speed relationships of the various components of the continuously variable transmission mechanism continuously change. Specifically, the rotational speed of the internal gear 5 gradually increases negatively, while the rotational speed of the sun gear 7 gradually decreases negatively from the first set speed. This causes the speed difference between the engaging parts of the second clutch 10 to gradually decrease until it reaches zero. At this point, the vehicle speed reaches the highest value in the low-speed forward section. Engaging the second clutch 10 and disengaging the first clutch 9 completes the shift in gear ratio, entering the high-speed forward section. Because there is no speed difference between the engaging parts during the shift, a smooth transition can be achieved. Furthermore, it should be noted that the highest value in the low-speed forward section should not be lower than the maximum operating speed requirement.

[0042] After entering the high-speed section, gradually increase the displacement of variable motor 3 to the maximum, then decrease the displacement of variable pump 2 and continue to increase it in the opposite direction. This will cause the speed of sun gear 7 to gradually increase in the negative direction, and the speed of internal gear 5 to gradually decrease in the negative direction and then gradually increase in the positive direction. Output shaft 12 will drive the whole vehicle to continue to increase the vehicle speed. When the displacement of variable pump 2 reaches the maximum in the reverse direction, the vehicle speed reaches the highest value in the positive direction.

[0043] By using the continuously variable transmission mechanism in this technical solution, a variable pump 2 and a variable motor 3, both of which are variable elements, are used to couple the internal gear 5 and the sun gear 7 to achieve dual-variable composite speed regulation, increasing the speed regulation range. During the forward driving phase, the speed change process from 0 speed to the maximum working speed can be completed without switching the clutch. There is no circulating power generation during the forward drive phase, resulting in high transmission efficiency, especially at the start-up stage. Moreover, from the maximum reverse speed to the maximum forward speed, the entire speed change process only involves one segment switch, and it is a zero differential switch, that is, switching from the forward low-speed segment to the forward high-speed segment, which can achieve uninterrupted power transmission and improve work efficiency. The planetary gear transmission mechanism has low rotational speeds for each component, which makes it easy to achieve a high-reliability design and improves the lifespan of each component.

[0044] In addition, for applications where the reversing speed requirement is relatively high, a reversing mechanism can be added to the input or output end of the continuously variable transmission mechanism to replace the method of reversing by reverse variable of variable pump 2 in this invention. If this method is used to achieve reversing, the requirement for reverse variable of variable pump 2 can be eliminated, but variable pump 2 must be allowed to operate in reverse.

[0045] This embodiment also provides a wheeled machine, which includes the aforementioned continuously variable transmission mechanism. Specifically, the wheeled machine is agricultural machinery and construction machinery, such as tractors, loaders, and off-road vehicles.

[0046] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A continuously variable transmission mechanism, characterized by comprising: include: A planetary gear transmission system includes an internal gear, a sun gear, and a planet carrier, with a drive mechanism connected to the planet carrier in a transmission connection. A hydraulic closed system couples the internal gear and the sun gear, converting the power of the internal gear and the sun gear into low-speed or high-speed output. A clutch system for switching to the low-speed range or the high-speed range; The output shaft is connected to the clutch system; The hydraulic closed system includes a variable pump and a variable motor. The input shaft of the variable pump is connected to the sun gear through a first gear pair, and the output end of the variable motor is connected to the internal gear through a second gear pair. The clutch system includes a first clutch and a second clutch. The output shaft is connected to the internal gear via the first clutch and a third gear pair, and the output shaft is connected to the sun gear via the second clutch and a fourth gear pair.

2. The continuously variable transmission mechanism according to claim 1, characterized in that, Both the first clutch and the second clutch are jaw clutches.

3. The continuously variable transmission mechanism according to claim 1, characterized in that, Both the first clutch and the second clutch are plate clutches.

4. The continuously variable transmission mechanism according to claim 1, characterized in that, Both the first clutch and the second clutch are normally open.

5. The continuously variable transmission mechanism according to claim 1, characterized in that, The variable displacement motor is a bent-shaft type.

6. The continuously variable transmission mechanism according to claim 1, characterized in that, The low-speed section includes a reversing low-speed section and a forward low-speed section, and the high-speed section is a forward high-speed section.

7. The continuously variable transmission mechanism according to claim 6, characterized in that, The maximum value of the forward low-speed section is greater than or equal to the maximum operating speed required by the vehicle.

8. A wheeled machine, characterized in that, Including the continuously variable transmission mechanism as described in any one of claims 1 to 7.

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