CVT speed change mechanism

Abstract

The CVT speed change mechanism comprises a box body, and the box body is provided with a driving belt wheel assembly and a driven belt wheel assembly; the driving belt wheel assembly comprises a conical driving fixed disc and a driving movable disc, a movable shaft is coaxially and rotatably connected to the side, back to the driving fixed disc, of the driving movable disc, the movable shaft is in sliding fit with the box body in the axial direction, and a fixed shaft is coaxially and rotatably arranged on the movable shaft; the fixed shaft and the movable shaft are connected through a cylindrical cam mechanism, the fixed shaft is connected with a worm and gear mechanism, and a motor connected with the worm and gear mechanism is installed on the box body. According to the scheme, the problem that in the prior art, a CVT speed change mechanism is single in performance is solved, and the CVT speed change mechanism can meet different use performance requirements such as dynamic performance, economical efficiency and balance.

Description

Technical Field

[0001] This invention relates to a continuously variable transmission device, specifically a CVT transmission mechanism. Background Technology

[0002] A CVT transmission is a continuously variable transmission that can achieve any gear ratio within its speed range. Traditional CVT transmissions are controlled by a purely mechanical structure, and the same transmission mechanism can only meet one requirement: either good power performance, low fuel consumption, or a balance between the two.

[0003] Chinese patent document CN205371498U discloses a metal belt continuously variable transmission (CVT) with speed regulation controlled by an electric motor, comprising: a drive shaft rotatably supported on a transmission housing for receiving rotational power from an engine or electric motor; a driven shaft rotatably supported on the transmission housing for outputting rotational power; a first lead screw shaft, hollow inside with threads on its outer surface, and rotatably fixed to the drive shaft; a second lead screw shaft, hollow inside with threads on its outer surface, and rotatably fixed to the driven shaft; a first speed regulating mechanism rotatably supported on a drive movable cone disc, and threadedly fitted with the first lead screw shaft, capable of driving the drive cone disc to move axially along the drive shaft; a second speed regulating mechanism rotatably supported on a driven movable cone disc, and threadedly fitted with the second lead screw shaft, capable of driving the driven movable cone disc to move axially along the driven shaft; a first motor driving the first lead screw shaft to rotate; and a second motor driving the second lead screw shaft to rotate. The advantages of this prior art are as follows: the pressurized speed regulating mechanism using a motor-controlled mechanical transmission reduces hydraulic components and maintenance difficulty, and the use of multi-screw drive improves transmission efficiency; the output shaft brake clutch of the speed regulating motor is coaxial with the speed regulating motor to achieve a fixed speed ratio output, prevent motor stalling, and extend the service life of the motor; the power input shaft of the clutch is coaxial with the power input shaft of the transmission, enabling the switching between forward and reverse gears of the transmission.

[0004] Although the aforementioned existing technologies can also achieve transmission ratio adjustment, their complex structure and high manufacturing cost make them unsuitable for widespread application. Summary of the Invention

[0005] The purpose of this invention is to provide a CVT transmission mechanism to solve the problem of limited performance of existing CVT transmission mechanisms.

[0006] To achieve the above objectives, the basic solution of the present invention provides a CVT transmission mechanism, including a housing, wherein the housing is provided with a driving pulley assembly and a driven pulley assembly; the driving pulley assembly includes a conical driving fixed disc and a driving movable disc, wherein a movable shaft is coaxially rotatably connected to the side of the driving movable disc opposite to the driving fixed disc, the movable shaft is slidably engaged with the housing along the axial direction, a fixed shaft is coaxially rotatably provided with the movable shaft, the fixed shaft and the movable shaft are connected by a torsion cam mechanism, the fixed shaft is connected to a worm gear mechanism, and a motor connected to the worm gear mechanism is mounted on the housing.

[0007] The beneficial effects of this basic scheme are as follows: By controlling the motor to drive the worm gear to rotate, the worm gear drives the worm wheel to rotate, which in turn drives the fixed shaft to rotate. This causes the fixed shaft and the moving shaft to rotate relative to each other, which in turn causes the fixed shaft to drive the moving shaft axially via a torsion cam mechanism. This, in turn, causes the moving shaft to drive the active moving disc to move. When the active moving disc moves towards the active fixed disc, the active pulley assembly compresses the belt, increasing the effective rotation radius of the active pulley assembly while the total length of the belt remains unchanged. Consequently, the effective rotation radius of the driven pulley assembly decreases, causing the transmission ratio of the CVT transmission mechanism to change from large to small. Furthermore, the worm gear mechanism has a self-locking function, allowing the transmission ratio of the CVT transmission mechanism to be stabilized at the corresponding position. This scheme simplifies the structure of the CVT transmission mechanism, makes the transmission ratio adjustment convenient and reliable, and enables the CVT transmission mechanism to meet different performance requirements such as power, economy, and balance, thus improving the practicality of the CVT transmission mechanism.

[0008] Preferably, the movable shaft is sleeved on the outside of the fixed shaft. This arrangement enhances structural stability and reduces space requirements.

[0009] Preferably, the torsion cam mechanism includes a guide pin extending radially along a fixed shaft, the guide pin being connected to the fixed shaft. The torsion cam mechanism also includes a slide groove disposed on a movable shaft, the slide groove being in sliding engagement with the guide pin. This configuration simplifies the design of the torsion cam mechanism, improves the transmission reliability between the movable and fixed shafts, and reduces maintenance operations.

[0010] Preferably, the housing includes a guide rod arranged parallel to the moving shaft, and the moving shaft is slidably connected to the guide rod. This arrangement simplifies and ensures reliable sliding contact between the moving shaft and the housing, thereby improving structural reliability.

[0011] Preferably, the active moving disk is connected to the moving shaft via a bearing. This arrangement allows the active moving disk to move axially together with the moving shaft while reducing wear between them, thereby improving structural reliability.

[0012] Preferably, an oil baffle is fitted on the outer side of the moving shaft, with both ends of the oil baffle sealingly fitted to the moving shaft. An oil seal is provided between the moving shaft and the fixed shaft near the end of the worm gear mechanism. This arrangement, by filling the space between the moving shaft and the fixed shaft with lubricating oil and sealing it with the oil baffle and oil seal, reduces wear between the moving shaft and the fixed shaft, thus extending service life and reducing maintenance. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of an embodiment of a CVT transmission mechanism according to the present invention; Figure 2 for Figure 1 Cross-sectional view of the central drive pulley assembly; Figure 3 for Figure 2 A schematic diagram of the active moving disc of the central active belt pulley assembly after it moves toward the active fixed disc. Detailed Implementation

[0014] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: 1. Driven pulley assembly; 2. Driven fixed disc; 3. Driven moving disc; 4. Motor; 5. Housing; 6. Guide rod; 7. Worm gear; 8. Slide groove; 9. Guide pin; 10. Worm wheel; 11. Bearing; 12. Oil baffle; 13. Moving shaft; 14. Fixed shaft; 15. Displacement cylinder; 16. Displacement sensor; 17. Controller.

[0015] The basic implementation examples are as follows: Figures 1 to 3 The diagram shows a CVT transmission mechanism, including a housing 6. The housing 6 houses a drive pulley assembly and a driven pulley assembly 1, which are connected by a transmission belt 2. The drive pulley assembly includes a conical drive fixed disc 3 and a drive moving disc 4. A spacer cylinder 16 is positioned between the drive fixed disc 3 and the drive moving disc 4, and the drive moving disc 4 slides in contact with the spacer cylinder 16.

[0016] The active moving disk 4 is coaxially rotatably connected to the moving shaft 14 on the side opposite to the active fixed disk 3. In this embodiment, the active moving disk 4 is connected to the moving shaft 14 via a bearing 12. The moving shaft 14 is slidably engaged with the housing 6 along the axial direction. In this embodiment, the housing 6 includes a guide rod 7 arranged parallel to the moving shaft 14, and the moving shaft 14 is provided with a sliding hole that engages with the guide rod 7, allowing the guide rod 7 to pass through the sliding hole and be slidably connected to the moving shaft 14. A fixed shaft 15 is coaxially rotatably arranged on the moving shaft 14. In this embodiment, the moving shaft 14 is sleeved on the outside of the fixed shaft 15. The fixed shaft 15 and the moving shaft 14 are connected by a torsion cam mechanism. In this embodiment, the torsion cam mechanism includes a guide pin 10 extending radially along the fixed shaft 15, and the guide pin 10 is connected to the fixed shaft 15; the torsion cam mechanism also includes a sliding groove 9 provided on the moving shaft 14, and the sliding groove 9 is slidably engaged with the guide pin 10.

[0017] A worm gear mechanism is connected to the fixed shaft 15, and a motor 5 connected to the worm gear mechanism is mounted on the housing 6. Specifically, the fixed shaft 15 is coaxially connected and fixed to the worm wheel 11, and the motor 5 is connected and fixed to the worm 8, so that the motor 5 drives the worm wheel 11 to rotate through the worm 8. An oil baffle 13 is fitted on the outer side of the moving shaft 14, and the two ends of the oil baffle 13 are sealed to the moving shaft 14. An oil seal is provided between the moving shaft 14 and the end of the fixed shaft 15 near the worm gear mechanism. A displacement sensor 17 for detecting the moving distance of the active moving disc is provided on the housing 6. The motor 5 is connected to a controller 18, which facilitates precise control of the motor 5.

[0018] The specific implementation process is as follows: Motor 5 drives worm 8 to rotate, which in turn drives worm wheel 11. This worm wheel 11 then drives fixed shaft 15 to rotate, causing fixed shaft 15 to rotate relative to moving shaft 14. Fixed shaft 15, through a torsion cam mechanism, drives moving shaft 14 axially, which in turn drives active moving disc 4. When active moving disc 4 moves towards active fixed disc 3, the active pulley assembly compresses the belt, increasing its effective rotation radius while maintaining the same belt length. Consequently, the effective rotation radius of driven pulley assembly 1 decreases, causing the CVT transmission ratio to change from large to small. Furthermore, the worm gear mechanism has a self-locking function, ensuring the CVT transmission ratio remains stable at the appropriate position. This solution simplifies the structure of the CVT transmission mechanism, makes transmission ratio adjustment convenient and reliable, and allows the CVT transmission mechanism to meet different performance requirements such as power, economy, and balance, thus improving its practicality.

[0019] When the CVT transmission mechanism of this invention is used in a vehicle, it enables the vehicle to have Sport mode, Economy mode, Balanced mode, and Autonomous control mode. For example, the controller 18 controls the motor 5 to adjust the transmission ratio of the CVT transmission mechanism. In Sport mode, the controller 18 sets the engine speed when the motor controls the CVT transmission mechanism to a high speed, such as when the speed is 1000 rpm higher than the torque point, resulting in strong power during vehicle start-up and acceleration. In Economy mode, the controller 18 sets the engine speed when the motor controls the CVT transmission mechanism to a low speed, such as when the speed is 1000 rpm lower than the torque point, resulting in weaker power during vehicle start-up and acceleration, but lower fuel consumption. In Balanced mode, the controller sets the engine speed when the motor controls the CVT transmission mechanism to a moderate speed, such as when the speed is at the torque point, resulting in a relatively balanced power and fuel consumption. In Autonomous control mode, the operator can adjust the engine speed when the motor controls the CVT transmission mechanism according to their preference.

[0020] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics in the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A CVT variator mechanism comprising a housing provided with a drive pulley assembly and a driven pulley assembly; the drive pulley assembly comprising a conical drive fixed disc and a drive mobile disc, characterised in that: The side of the active moving disc opposite to the active fixed disc is coaxially connected with a moving shaft, the moving shaft is in sliding fit with the box body in the axial direction, the moving shaft is coaxially provided with a fixed shaft, the fixed shaft and the moving shaft are connected through a torsion cam mechanism, the fixed shaft is connected with a worm and gear mechanism, and the box body is provided with a motor connected with the worm and gear mechanism.

2. A CVT variator mechanism according to claim 1, characterised in that: The moving shaft is sleeved on the outside of the fixed shaft.

3. A CVT variator according to claim 2, characterised in that: The torsion cam mechanism comprises a guide pin extending in the radial direction of the fixed shaft, the guide pin is connected with the fixed shaft, and the torsion cam mechanism further comprises a sliding groove provided on the moving shaft, and the sliding groove is in sliding fit with the guide pin.

4. A CVT variator according to claim 3, characterised in that: The box body comprises a guide rod arranged in parallel with the moving shaft, and the moving shaft is in sliding connection with the guide rod.

5. A CVT variator mechanism according to claim 4, characterised in that: The active moving disc is connected with the moving shaft through a bearing.

6. A CVT variator mechanism according to claim 5, characterised in that: An oil baffle is sleeved on the outside of the moving shaft, the two ends of the oil baffle are in sealing fit with the moving shaft, and an oil seal is arranged between the moving shaft and the end of the fixed shaft close to the worm and gear mechanism.

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