LV15703B - Stepless belt transmission - Google Patents

Abstract

The invention relates to a stepless belt transmission. The continuously variable belt transmission (20) contains the first shaft (1); the second shaft (2); adjustable V-belt pulley (3) mounted on the first shaft (i). The transmission (20) comprises a toothed pulley (6) attached to the second shaft (2) and a toothed V-belt (7) arranged on the adjustable V-belt pulley (3) and the driven toothed pulley (6) to transmit power from the V-belt pulley (3) to the toothed pulley (6). The transmission (20) additionally contains a belt tensioner (8) which is located between the V-belt pulley (3) and the toothed pulley (6). The belt tensioner (8) contains two tensioning rollers (10; 11) arranged against each other and the outer flanges of the toothed V-belt (7) so that the tensioning rollers (10; 11) can apply force to the toothed V-belt (7) from both sides , by tensioning the mentioned V-belt (7) from both sides.

Description

DESCRIPTION OF THE INVENTION

Technical sector

[001] The invention relates to a stepless belt drive.

Analysis of the prior art

[002] The prior art describes various stepless belt drives. A typical stepless belt drive is described in US Patent Publication Nos. US 4541821 and US4717368, European patent application publication no. EP2487386 and Chinese patent application publication no. CN101245851. The aforementioned publications describe a stepless belt drive comprising a first shaft, an adjustable belt pulley having two side discs mounted on the first shaft, wherein at least one side disc is axially adjustable along the first shaft, a second shaft positioned parallel to the first for the shaft, a driven pulley attached to the second shaft, and an endless belt placed on the adjustable belt pulley and the driven pulley to transmit power from the adjustable belt pulley to the driven pulley.

[003] In order to ensure effective engagement between the pulleys, a tension roller may be inserted into the stepless belt conveyor as indicated in Japanese Patent Application Publication No. JPS5926654.

[004] The object of the invention is to create a stepless belt drive that provides the best possible engagement between the drive pulley and the driven pulley, as well as improved belt performance compared to the prior art. A further object of the invention is to simplify the transmission without reducing its efficiency.

Outline of the invention

[005] The object is achieved by designing a stepless belt drive comprising a first shaft, a second shaft parallel to the first shaft, an adjustable V-belt pulley comprising two side discs mounted on the first shaft, and a driven toothed pulley attached to second shafts. At least one of the two side discs of the adjustable V-belt pulley is axially adjustable along the first shaft. The side disk can be axially adjusted mechanically, hydraulically, pneumatically or electronically, so that during adjustment the diameter of the V-belt pulley changes in the contact circle of the endless toothed V-belt. The endless V-belt itself is located on the adjustable V-belt pulley and the driven toothed pulley to transmit the power from the adjustable V-belt pulley to the driven toothed pulley.

[006] The continuously variable belt drive also includes a belt tensioner located between the adjustable V-belt pulley and the driven toothed pulley. The belt tensioner comprises a guide and two tensioning rollers slidably mounted on the guide and positioned against each other and on the outer flange of the endless toothed V-belt so that the tensioning rollers apply a force to both sides of the toothed V-belt toward each of the tensioning rollers or to tension said V-belt from both sides of it.

[007] The present invention includes a mechanically, hydraulically, pneumatically, electronically or otherwise adjustable V-belt pulley. The adjustment is made by moving its side discs further or closer to each other (axial movement), so the diameter of the V-belt pulley decreases or increases in the circle of V-belt contact, where the angle of the V-belt corresponds to the angle of the groove of the V-belt pulley. The tooth profile of the toothed pulley corresponds to a toothed V-belt. Changes in timing belt tension in the carriage resulting from adjusting the diameter of the V-belt pulley in the timing belt contact circle are compensated by the aforementioned belt tensioner.

[008] In a preferred embodiment of this invention, the guide comprises a trapezoidal lead screw with a right-hand thread on one side and a left-hand thread on the other side. One tension roller is placed on the right-hand thread of the trapezoidal lead screw, and the other tension roller is placed on the left-hand thread of the trapezoidal leadscrew, so that when the trapezoidal leadscrew rotates in one direction, the two tension rollers are directed toward each other, and when the trapezoidal leadscrew rotates in the opposite direction, both tensioners the vertebrae are pushed away from each other.

[009] The following invention provides an efficient transmission while maintaining the ability to adjust the gear ratio by acting on only one of the elements (driving or driven). In addition, the use of two tension rollers provides a larger contact surface between the V-belt and the adjustable V-belt pulley and toothed pulley. In addition, the use of two tension rollers allows the V-belt to be tensioned at a wider angle than would be possible with only one tension roller. Also, on a toothed pulley, the V-belt works with the teeth, while on an adjustable V-belt pulley, the V-belt works with the side surfaces. Thus, the load is distributed between the teeth and the side surface of the V-belt and the service life of the V-belt is increased.

List of drawings

[010] The drawings illustrate various embodiments of the invention by way of examples.

[011] Fig. 1 is a front perspective view of a kart (30) equipped with a stepless belt drive (20).

[012] Fig. 2 is a close-up of the stepless belt drive (20) shown in Fig. 1.

[013] Fig. 3 is a top view of the stepless belt drive (20) shown in Figs. 1 and 2.

[014] Fig. 4 is a front perspective view of the stepless belt drive (20) shown in Figures 1 to 3 equipped with a toothed V-belt (7).

[015] Fig. 5 is a front view of the stepless belt drive (20) shown in Figs. 1 to 4, where the two tension rollers (10; 11) are moved farthest apart.

[016] Fig. 6 is a front view of the stepless belt drive (20) shown in Fig. 1 to

Fig. 5, where the two tensioning pulleys (10; 11) are pulled farthest from each other.

[017] Fig. 7 is a front view of the stepless belt drive (20) shown in Fig. 1 to

Fig. 5, where two tension rollers (10; 11) are moved closest to each other.

Detailed presentation of examples of implementation of the invention

[018] Preferred embodiments of the invention are described below with reference to the drawings in order to illustrate the purpose, advantages and effectiveness of the present invention.

[019] Fig. 1 shows a go-kart (30) equipped with a stepless belt drive (20). The stepless belt drive (20) is mounted on the kart (30) frame (31).

[020] Figures 2 to 6 shows a continuously variable belt drive (20) containing the first shaft (1). The first shaft (1) is the shaft of the electric motor (32) installed on the kart (30) frame (31). The continuously variable belt drive (20) contains an adjustable V-belt pulley (3) which contains two side pulleys (4;5) mounted on the first shaft (1). One side pulley (4) is axially adjustable along the first shaft (1). The axial adjustment of one side pulley (4) relative to the other side pulley (5) is realized using a mechanical actuator (12). The stepless belt drive (20) contains a second shaft (2) positioned parallel to the first shaft (1). In this embodiment of the invention, the second shaft (2) is a driven shaft (2) with kart (30) wheels (33) attached to it. A toothed pulley (6) is attached to the second shaft (2). The stepless belt drive (20) includes an endless toothed V-belt (7) located on the adjustable V-belt pulley (3) and the driven toothed pulley (6) to transmit power from the adjustable V-belt pulley (3) to the driven toothed pulley (6).

[021] The stepless belt drive (20) is characterized in that the stepless belt drive contains a belt tensioner (8) which is placed between the adjustable V-belt pulley (3) and the driven toothed pulley (6) so that the belt tensioner (8) ) could automatically tension the endless toothed V-belt (7) placed between them. The belt tensioner (8) comprises a guide (9) and two tension rollers (10; 11) which are slidably mounted on the guide (9) and are positioned against each other and on the outer flange of the endless toothed V-belt (7) so that the tension rollers (10; 11), moving towards each other, would press the endless toothed V-belt (7) from both sides (see fig. 2 to 6).

[022] In the preferred embodiment of this invention, shown in Figs. 1 to 6, the guide (9) of the belt tensioner (8) contains a trapezoidal lead screw (91) with a right-hand thread on one side and a left-hand thread on the other side. One tension roller (10; 11) is placed on the right thread of the trapezoidal lead screw (91), and the other tension roller (10;l 1) is placed on the left thread of the trapezoidal leadscrew (91) so that when turning the trapezoidal leadscrew (91) in one direction , the two tensioning rollers (10; 11) are moved towards each other and by turning the trapezoidal lead screw (91) in the opposite direction, the two tensioning pulleys (10; 11) are moved away from each other. The rotation of the trapezoidal lead screw (91) is provided with the help of an electric motor - stepper motor (92), which is connected to the said lead screw (91).

[023] Fig. 4 shows a continuously variable belt transmission (20) containing the endless toothed V-belt (7). Fig. 3 and 6 illustrates the stepless belt drive (20) without the endless toothed V-belt (7) to facilitate understanding of other elements of the stepless belt drive (20). The adjustable V-belt pulley (3) with two side pulleys (4; 5) and the toothed pulley (6) can be seen more clearly without the endless toothed V-belt (7).

[024] Figures 4 to 6 shows the operation of the stepless belt drive (20), particularly the operation of the belt tensioner (8) and its tensioning rollers (10; 11). Figs. 4 and 6 illustrates the situation when the two tensioning rollers (10; 11) are moved as close as possible to each other and the endless toothed V-belt (7), as seen in Fig. 4, is maximally tensioned. Fig. 5 illustrates the situation when both tensioning rollers (10; 11) are moved away from each other in their farthest positions and the endless toothed V-belt (7) will not be tensioned at all, as can be seen in Fig. 4.

[025] While the invention may be susceptible to various modifications and alternative forms, specific solutions of which are exemplified in the drawings and described in detail herein, it is to be understood that the invention is not intended to be limited to the forms specifically disclosed herein. Rather, the invention includes all modifications, equivalents, and alternatives that fall within the scope of the invention as defined in the following claims.

Claims (4)

1. Continuous belt transmission (20) containing: - the first shaft (1); - an adjustable V-belt pulley (3) containing two side discs (4;5) mounted on the first shaft (1), in addition, at least one side disc (4 or 5) is axially adjustable along the first shaft (1); - the second shaft (2), placed parallel to the first shaft (1); - driven toothed belt pulley (6) attached to the second shaft (2); - an endless toothed V-belt (7) placed on the adjustable V-belt pulley (3) and the drive toothed pulley (6) to transfer power from the adjustable V-belt pulley (3) to the driven toothed belt pulley (6), characterized by the fact that the stepless belts transmission (20) contains a belt tensioner (8) located between the adjustable V-belt pulley (3) and the driven toothed belt pulley (6), in addition, the belt tensioner (8) contains a guide (9) and two tension rollers (10; 11) which slidably mounted on a guide (9), further, two tensioning rollers (10; 11) are arranged against each other and on the outer flange of the endless toothed V-belt (7), and further, the guide (9) is configured to move the two tensioning rollers (10; 11) so that the tensioning rollers (10; 11) tension the endless toothed V-belt (7) from both sides towards each of the tensioning rollers (10; 11). 2. A continuously variable belt transmission (20) according to claim 1, characterized in that the guide (9) comprises a trapezoidal lead screw (91) with a right-hand thread on one side and a left-hand thread on the other side, where one tension roller (10;ll ) is placed on the right thread of the trapezoidal lead screw (91) and the second tension roller (10; 11) is placed on the left thread of the trapezoidal lead screw (91) so that when the trapezoidal lead screw (91) is turned in one direction, both tension rollers (10; 11) ) move towards each other and when turning the trapezoidal lead screw (91) in the opposite direction, the two tension rolls (10; 11) move away from each other. 3. Continuous belt transmission (20) according to claim 1 or 2, characterized in that at least one side pulley (4;5) is mechanically, hydraulically, pneumatically or electronically movable axially, so that during adjustment the V-belt pulley (3 ) diameter changes in the contact arc of the toothed V-belt (7). A continuously variable belt drive (20) according to any one of claims 1 to 3, characterized in that the guide (9) simultaneously moves both tension rollers (10; 11) towards and away from the endless toothed V-belt (7).