CONTROL MECHANISM DEVELOPED FOR CONTINUOUSLY VARIABLE TRANSMISSION (CVT)SYSTEM

Abstract

The invention relates to the control mechanism developed for continuously variable transmission systems which are chain/belt-driven and which are used in the vehicles with electrical, hybrid and conventional internal combustion engine as an automatic gearbox system in the automotive industry.

Claims

1- A control mechanism for transmitting the power from the input part to the output part uninterruptedly, non-gradually and continuously by means of the Continuous Variable Transmission (SDA, CVT) systems, it comprises; an input pulley (101) that transmits the torque from the input to the output part over a transmission element (103), an output pulley (102) that transmits the torque transmitted by the transmission element (103) to the related machine element over the output shaft, the transmission element (103) that transmits torque from the input pulley (101) to the output pulley (102), characterized by comprising; a control arm (107) providing gear shifting in the continuous variable transmission system, a drive element (108) providing determining the gear ratio by thrusting the control arm (107) back and forth, a control roller (104) which is a protrusion of the control arm (107), and which is thrusted by the drive element (108) to control the position of the transmission element (103). a control arm trajectory (105) thrusted by the drive element (108) to determine the cycle ratio of the continuously variable transmission, a control arm bearing (106) providing bearing of the control arm (107) from top. a drive arm (109) providing the movement of the control arm (107) through converting the thrust rotation movement from the drive element (108) into the thrust movement, an input pressure spring (110) providing the non-slidable rotation of the transmission element by pressing the contact points of the transmission element (103) between the input pulleys (101), an output pressure spring (111) enables the non-slidable rotation of the transmission element by pressing the contact points of the transmission element (103) between the output pulleys (102).

2- A control mechanism (100) according to claim 1, characterized by comprising; the drive element (108), which provides determining the gear ratio by thrusting the control arm (107) back and forth, is selected as servo motor.

3- A control mechanism (100) according to claim 1, characterized by comprising; said drive arm (108), which provides movement of the control arm (107) is a worm gear.

4- A control mechanism (100) according to claim 1, characterized by comprising; said control roller (104) is an external roller.

5- A control mechanism (100) according to claim 1, characterized by comprising; said transmission element (103) is chain or belt.

6- A control method for transmitting the power from the input part to the output part uninterruptedly, non-gradually and continuously by means of the Continuous Variable Transmission (SDA, CVT) systems, characterized by comprising; the follow method steps of; determining the gear ratio mechanically by the drive element (108) in the Continuous Variable Transmission (CVT) system, moving the drive arm (109) back and forth by rotating drive element (108) in different directions, moving the control arm (107) in trajectory (105) as a result of the back-and-forth movement of the drive arm (109).

7- A control method for transmitting the power from the input part to the output part uninterruptedly, non-gradually and continuously by means of the Continuous Variable Transmission (SDA, CVT) systems according to claim 6, characterized by comprising; the method step of raising or lowering of the chain by forcing the chain/belt of the continuously variable transmission system such that the control roller (104) moves to follow the control arm trajectory (105) with the movement of the control arm (107) in the trajectory (105).

Description

FIGURES FOR A BETTER UNDERSTANDING OF THE INVENTION

[0019] The present invention should be evaluated together with the figures explained below, in order to better understand the embodiment of the invention and its advantages with the additional elements.

[0020] FIG. 1; two-dimensional view of the continuously variable transmission control mechanism according to the invention in equilibrium.

[0021] FIG. 2 two-dimensional view of the continuously variable transmission control mechanism according to the invention with reduced output speed.

[0022] FIG. 3 two-dimensional view of the continuously variable transmission control mechanism according to the invention with increased output speed.

LIST OF REFERENCE NUMBERS

[0023] 100—Control mechanism [0024] 101—Input pulley [0025] 102—Output pulley [0026] 103—Transmission element [0027] 104—Control roller [0028] 105—Control arm trajectory [0029] 106—Control arm bearing [0030] 107—Control arm [0031] 108—Drive element [0032] 109—Drive arm [0033] 110—Input pressure spring [0034] 111—Output pressure spring

DETAILED DESCRIPTION OF THE INVENTION

[0035] The invention enables providing a power transmission with only one servo motor in order to ensure that the power transmission control of Continuous Variable Transmission (CVT) systems is produced with a mechanical solution instead of a hydraulic power unit.

[0036] In order to ensure transmitting the power from the input part to the output part uninterruptedly, non-gradually and continuously by means of the Continuous Variable Transmission (SDA, CVT) systems, there is provided an input pulley (101) that transmits the torque from the input to the output part over a transmission element (103). An output pulley (102) transmits the torque transmitted by the transmission element (103) to the related machine element over the output shaft. Power transmission element (103) which is selected as chain-belt transmits the torque from the input pulley (101) to the output pulley (102).

[0037] Control arm (107) provides gear shifting in the continuous variable transmission system. The drive element (108) selected as servo motor provides determining the gear ratio by thrusting the control arm back and forth There is provided the control roller (104) thrusted by the drive element (108) to control the position of the transmission element (103). There is provided a control arm trajectory (105) thrusted by the drive element (108) to determine the cycle ratio of the continuously variable transmission. A control arm bearing (106) enables bearing of the control arm (107) from top. There is provided the drive arm (109) enabling the movement of the control arm (107) through converting the thrust rotation movement from the drive element (108) into the thrust movement. Said drive arm (109) is preferably a worm gear. Input pressure spring (110) enables the non-slidable rotation of the transmission element by pressing the contact points of the transmission element (103) between the input pulleys (101). An output pressure spring (111) enables the non-slidable rotation of the transmission element by pressing the contact points of the transmission element (103) between the output pulleys (102).

[0038] A control method providing transmitting the power from the input part to the output part uninterruptedly, non-gradually and continuously by means of the Continuous Variable Transmission (SDA, CVT) systems, wherein; it comprises the steps of determining gear ratio by means of drive element (108) in the Continuous Variable Transmission (CVT) system, moving the drive arm (109) back and forth by rotating drive element (108) in different directions, moving the control arm (107) in trajectory (105) as a result of the back and forth movement of the drive arm (109), raising or lowering of the chain by forcing the chain/belt of the continuously variable transmission system such that the roller (104) moves to follow the trajectory (105) with the movement of the control arm (107) in the trajectory (105). The control roller (104) which is a protrusion of said control arm (107), is preferably an external roller.

[0039] Continuous Variable Transmission (SDA, CVT) control mechanism according to the invention has an operation principle as follows;

[0040] FIG. 1 shows two-dimensional view of the Continuously Variable Transmission control mechanism (100) according to the invention in equilibrium. As shown in the figure, the drive element (108), selected as a servo motor is used for CVT gear ratio control. Thanks to said motor (108), it is provided to control the position of the chain and belt, and mechanically determine the gear ratio. In order to achieve this, it is provided to move the drive arm (109) back and forth with respect to the rotation direction of the servo motor (108), and to move the control arm (107) within the bearing (106).

[0041] FIG. 2 shows two-dimensional view of the continuously variable transmission control mechanism (100) according to the invention with reduced output speed. In a case where the control arm (107) is thrusted forward, the pulley (104) is moved to the right in the trajectory (105). As a result of this movement, transmission element (103), selected as chain/belt widens along the right output pulley (102) and the radius of contact thereof increases. Since the length of the chain/belt is fixed, the distance between the left pulleys (101) becomes larger and the chain/belt, namely the transmission element (103) moves downward. At the same time, the distance between the right output pulleys (102) becomes smaller and the area of the chain/belt on this side moves upward. Therefore, the cycle ratio of the CVT system has altered and speed on the outlet part is reduced thus the torque is increased. As a result of this, the compression springs (110) (111) which makes the chain/belt non-slidable will be compressed and expanded, respectively.

[0042] FIG. 3 shows two-dimensional view of the continuously variable transmission control mechanism (100) according to the invention with increased output speed. Similarly, thanks to the servo motor (108), the control arm (107) is thrusted to the left in order to increase the speed of the CVT system on the outlet side and the position of the chain/pulley between the pulleys (101) is changed such that it is the opposite of the abovementioned position and gear ratio is changed thus output speed is increased.

[0043] Therefore, the gear (cycle) ratio of the CVT system is adjusted by continuously changing the position of the chain/belt with regard to the rotation angle of the servo motor (108) based on the trajectory (105) such that the ratio remains within the determined maximum and minimum values. The change limits and the change of positions thereof is controlled by the motor (108) through a control algorithm.