Technical Field

The present invention relates to the transmissions useful for decreasing and increasing the number of revolutions of rotary systems.

Prior Art

At the present, various transmission systems have begun to be used especially in the motor vehicles. As known, conventional transmission systems decrease and increase the number of revolutions in a stepwise manner. During the recent years, the transmission systems with the ability of decreasing and increasing the number of revolutions in a stepless manner have also begun to be used. These are generally called the CVT transmission systems.

However, the known CVT transmission systems have drawbacks in two respects. Firstly, they are limited in terms of increasing the gear ratio. Secondly, they are required to decrease the pulley bevel angles in order to be able to slightly increase the ratio. This in turn causes the transmission belt to become jammed inside the acute angled pulley and hence, the problems of friction, heating and efficiency loss emerge. In the state of the art CVT system, this angle has been reduced down to 9+9=18 degrees.

Object of the Invention

The present invention paves the way for the manufacture of the higher ratio CVTs, since, based on its structure, it has no limitation in terms of increasing the ratio. Further, because it will be possible to employ the pulley sides with obtuse angle, the problems of jamming of the belt inside the pulley, friction and heating encountered in the known CVTs will be solved. Whereas the necessity exists in the known CVTs to use a steel belt due to their acute angle, it will be possible with the invention to use also the less costly conventional V-belt.

Description of the Figures

The High Ratio CVT Transmission realized to achieve the object of the present invention is shown in the enclosed figures.

Figure 1: A perspective view of the High Ratio CVT Transmission according to the invention

Figure 2: A top view of the invention Figure 3: A top view of the invention Figure 4: A perspective view of the two-piece pulley Figure 5: A perspective view of the two-piece pulley Figure 6: A perspective view of the two-piece pulley Figure 7: An interior view of a pulley piece Figure 8: An exterior view of a pulley piece Figure 9: A view of the motion arm

Figure 10: A detailed sectional view of the pulley and the pulley shaft

Description of the Reference Numerals in the Figures

1: Input shaft 2: Output shaft 3: Spline shafts 4: Moving pulley piece 5: Fixed pulley piece 6: Motion arm 7: Bearing 8: Bearing shaft 9: Chassis 10: Gear belt

11: V-belt 12: Geared reel

13: Spline shafts control extension

14: Pulley fixing piece

15: Bearing groove

16: Motion arm nut

17: Pulley protrusions

18: Pulley grooves

19: Bearing ball

20: Input pulley

21: Output pulley

Description of the Invention

The present invention, which is a High Ratio CVT Transmission enabling the rotational movement applied to the input shaft (1) to be output from the output shaft (2) either by increasing or decreasing, is enclosed in all directions by the chassis (9). (Some of the covers of the chassis (9) have been removed from the view in Figure 1 in order to facilitate the description of the invention). The invention has two main shafts (1-2) whereby the input and output of the rotational power are performed. One of these is the input shaft (1) and the other is the output shaft (2). These shafts (1-2) are fitted in the bearing manner to the chassis (9) on two ends. Two pulleys (20-21) are present in the middle of these two shafts (1-2). One of these is the input pulley (20) and the other is the output pulley (21). On these two pulleys (20-21), there is present the V-belt (11) enabling the transfer of power from one pulley to the other pulley. There are also present 6 spline shafts (3) fitted in the bearing manner to the chassis (9), 2 gear belts (10) enabling these shafts (3) to rotate synchronously in the same direction and 8 geared reels (12) to which said belts are connected. The opening and closing positions of the pulleys (20-21) are determined via the forward and backward rotations performed by means of the spline shafts control extension (13) formed by way of extension out of the chassis (9) from any one of the spline shafts (3) and in any direction. The opening and closing of said pulleys (20-21) are provided by the motion arms (6) that move on the spline shafts (3) and the bearings (7) connected to the same. 4 motion arms (6) that are available in the system move in a synchronous manner to keep under control the moving pulley piece (4) that is pressed outward by the V-belt (11), via the bearings (7) on the same.

Reference will be made to Figure 2 and Figure 3 to describe the operating logic of the invention. Assume that a rotational movement at 3000 rpm is input via the input shaft (1) of Figure 2. Since the diameter of the output pulley (21) in Figure 2 is 3 times greater than that of the input pulley (20), the number of revolutions of the output shaft (2) will be 1000 rpm. The motion arms (6) are shifted to the left by way of intervention from the spline shafts control extension (13). In this case, the diameter of the input pulley (20) becomes 3 times greater, and conversely, the diameter of the output pulley (21) becomes 3 times smaller. The pulleys (20-21) assume the position in Figure 3. According to Figure 3, the value of 3000 rpm applied to the input shaft (1) will exhibit a threefold increase at the output shaft (2) to reach 9000 rpm. In other words, the ratio between the smallest gear position and the greatest gear position of the invention is 9. Knowing that the gear ratios employed in the automobiles of the present are around 4 - 4,5, this feature of the invention will be better appreciated.

We can consider the features of the High Ratio CVT Transmission according to the invention under 3 headings.

1- Special pulley structure: The pulleys (20-21) of the invention consist of two pieces (4-5) and the pulley pieces (4-5) are able to approach towards and move away from one another to a greater extent owing to the pulley protrusions (17) and pulley grooves (18) available on said two pieces (4-5). In other words, they are able to get in and out of each other.

2- Motion arms: The system that moves the pulley pieces (4-5) closer to and away from one another to such an extent to enable the same to get in and out of each other is the motion arms (6). The motion arms (6) that move together on the spline shafts (3) press on the rotating pulleys (20-21) by means of the bearings (7) located on the same, to thereby position said pulleys (20-21). 3- Linear bearing: In the system, the fixed pulley pieces (5) remain stationary, whereas the moving pulley pieces (4) perform the reciprocal motion. There is present the linear bearing between the pulley protrusions (17) of the moving pulley piece (4) and the input and output shafts (1-2) to enable said motion to occur in a manner free of friction. It is the bearing grooves (15) and the bearing balls (19) that provide for said bearing.

Industrial Applicability of the Invention

The high ratio CVT transmission is suitable for use in all the machines and implements operating based on rotational movement.