WO2020108828A1

WO2020108828A1 - Flexible drive means for a flexible drive

Info

Publication number: WO2020108828A1
Application number: PCT/EP2019/076363
Authority: WO
Inventors: Hubert Göser; Andre Kucharczyk
Original assignee: Contitech Antriebssysteme Gmbh
Priority date: 2018-11-28
Filing date: 2019-09-30
Publication date: 2020-06-04
Also published as: DE102018220416A1

Abstract

The invention relates to a flexible drive means for a flexible drive (10), in the case of which a flexible drive means drive wheel (5) is drive-connected via a flexible drive means (9) to a flexible drive means output wheel (8). The flexible drive means drive wheel (5) and the flexible drive means output wheel (8) are configured in each case as a toothed pulley (12, 13), and the flexible drive means (9) is configured as a toothed belt (11). The toothed belt (11) has a belt body (14), in which reinforcing members (16) are arranged. A belt upper side (15) is adjoined by radially inwardly extending side flanks (17, 18), the spacing of which on the belt upper side (15) forms the belt width (b). The two side flanks (17, 18) are adjoined radially on the inside by in each case one tooth flank (20, 21) of the belt teeth (19), which tooth flanks (20, 21) end radially on the inside at a common tooth tip (22). In order for it to be possible for alignment errors between the toothed pulleys (12, 13) to be compensated for, it is provided that at least one tooth flank (20; 21) of the respective belt teeth (19; 19a) has a tooth wedge flank (36) which opens into the tooth tip (22) and which forms a run-in slope (32) of the toothed belt (11), and that the tooth width (bZ) of the tooth tip (22) is smaller than the belt width (b). The invention also relates to the use of said flexible drive means and of a flexible drive (10) equipped therewith in industrial applications and on a vehicle.

Description

description

Traction device for a traction drive

The invention relates to a traction mechanism for a traction mechanism drive, in which a traction mechanism drive wheel is drive-connected via a traction mechanism to a traction mechanism output wheel, the traction mechanism drive wheel and the traction mechanism output wheel each being designed as a toothed pulley and the traction mechanism as a toothed belt having a plurality of belt teeth, the toothed belt being a belt body has, in which thread-like strength members are arranged, the belt body having a belt top radially outside, to which radially inward extending side flanks are connected, the two side flanks in the area of the belt top having an axial distance from one another forming the belt width, and in that a tooth flank of the belt teeth connects to the two side flanks radially on the inside, which end at a common tooth head, which is aligned parallel to the top of the belt and forms the radial inside of the toothed belt.

Generic toothed belts and traction drives are used for example in industrial applications and vehicles. Relevant industrial applications are, for example, different types of actuators, such as finear drives, door drives or drives for compressors and pumps. In vehicles such Zugmittelan drives, for example in two-wheeled vehicles, such as motorcycles and bicycles for appli cation. For example, bicycles usually have a traction mechanism drive which has a traction mechanism drive wheel which is mounted in a bottom bracket and is connected to pedals and which is drive-connected via an endless traction mechanism to a traction mechanism drive wheel arranged on a hub of a drivable rear wheel. Regardless of the type of application, the traction device is usually a chain. Such chains as traction devices have the disadvantage that they lengthen during operation and have to be excited. In addition, chains tend to rattle and harbor the risk of soiling the driver's clothing.

Traction drives for bicycles have also been proposed, in which a toothed belt is used instead of a chain. Such a solution is described for example in DE 36 29 789 C2.

Compared to chains as traction devices, toothed belts have the advantage that they do not lengthen, or at least only to a small extent, are lighter and function practically noiselessly during operation. For example, when using such a Zugmittelan drive on a bicycle, however, there are particular problems which have their cause in the comparatively strong torsion of the frame of the bicycle during its operation. This twisting of the frame means that an exact alignment of the two tooth lock washers is not possible under all circumstances. The consequence of this is that the toothed belt does not run exactly into the associated toothed pulley and, in spite of the inclined run-in angles of the flanged wheels of the toothed pulleys, runs and tears on the flanged wheels or even jumps off the toothed pulley. Such a problem can also occur in the above-mentioned industrial applications if, for whatever reason, there is no exact alignment of the two toothed disks with one another.

The invention was therefore based on the object to remedy this situation and to design a traction mechanism of the type mentioned in such a way that the existing disadvantages do not occur with the traction mechanism drives mentioned. In particular, a traction device should be created, in which a damage-free entry of the traction device into the toothed washer is ensured and a jumping off of the traction device from the toothed washer is excluded. Finally, this traction drive should be used in all types of industrial applications and vehicles.

This object is achieved by a traction device with the features of claim 1.

Another independent claim relates to a traction mechanism drive which is equipped with a traction device according to the invention. Advantageous further developments are in the dependent claims. The claims 12 to 14 indicate advantageous uses of the traction drive according to the invention.

The invention accordingly relates to a traction device for a traction drive, in which a traction drive wheel is antriebsverbun via a traction device with a traction drive wheel, the traction drive wheel and the traction drive wheel each as a toothed disk and the traction device as a toothed belt with a plurality of belt teeth being formed, the Toothed belt has a belt body, in which thread-like strength members are arranged, the belt body having a belt upper side radially on the outside, to which radially inwardly extending side flanks are connected, the two side flanks in the region of the belt upper side being at an axial distance from one another forming the belt, and in which a tooth flank of the belt teeth adjoins the two side flanks radially inside, which end at a common tooth head, which is aligned parallel to the top of the belt and forms the radial inside of the toothed belt.

In order to achieve the object, this traction device provides that at least one tooth flank of the respective belt teeth has a tooth wedge flank which opens into the tooth head, which forms an entry slope of the toothed belt, and that the tooth width of the tooth head is smaller than the belt width.

The invention was based on the knowledge that the task can be solved in a surprisingly simple manner in that the belt teeth each have a toothed wedge flank at least on one side in the region of the transition to the tooth head, which forms a run-in slope of the belt tooth or the toothed belt. The toothed belt itself thus has at least one run-in slope, which supports damage-free entry of the toothed belt into the respective toothed pulley even when the two toothed pulleys are offset from one another. This has proven to be sufficient to reliably prevent the toothed belt from tearing or running off.

In addition, it can be provided that the tooth flanks of the belt teeth at least in a tooth wedge segment opening into the tooth head at a tooth flank angle. are aligned, which deviates from the orientation of at least one of the side flanks and is between 5 ° and 45 °, preferably between 10 ° and 20 °.

According to another advantageous development, it can be provided that the height of the respective toothed wedge segment is between 50% and 100%, preferably 80%, of the total height of the belt tooth.

Another embodiment of the invention provides that the tooth flanks of the toothed belt, which form a straight toothed segment, extend radially inward and run perpendicularly with respect to an imaginary plane below the reinforcement bars, this imaginary plane geometrically separating the belt body from the respective toothed segment, and that the beveled tooth wedge segment connects to this straight tooth segment, the height of the straight tooth segment being less than the total height of the belt tooth.

It is also within the scope of the invention to provide that the belt teeth are designed asymmetrically, the opposing tooth flanks being aligned in different tooth flank angles or inclined angles or being provided with different heights.

Also particularly advantageous is an embodiment of the invention, which is characterized in that the tooth flanks are provided with a friction and noise-reducing coating.

It can further be provided that at least one entire side flank of the toothed belt is formed into an entry slope which begins at the top of the belt and extends at a constant slope angle to the tooth head over the entire belt height. This configuration can be supplemented by the fact that the bevel angle is between 5 ° and 45 °, preferably between 10 ° and 20 °.

Alternatively, it can be provided that the belt teeth are formed symmetrically, the tooth flanks lying opposite one another under the same tooth flank. are aligned or are seen with the same heights in the tooth flank angle or helical angle and each with a similarly designed inlet bevel.

A traction mechanism drive equipped with the traction device according to the invention is characterized in that the inner side walls of at least one toothed pulley are provided with a friction and noise-reducing coating at least in the area of the toothed belt. In addition, it can be provided that the toothed disks each have flanged axially axially on both sides with inlet slopes arranged radially on the outside.

The toothed belt described and the traction mechanism drive are particularly advantageous in industrial applications, such as different types of actuators, such as linear drives, door drives or drives for compressors and pumps, and in vehicles, for example in two-wheeled vehicles, which also include motorcycles and bicycles.

Further features, advantages and details of the invention are described in more detail with reference to the accompanying drawing, which schematically represents exemplary embodiments of the invention. It shows

1 an embodiment of a traction drive of a bicycle seen from the side,

FIG. 2 shows the traction mechanism drive in cross section along the line A-A 'according to FIG. 1 in a partial view, and

3 shows a cross-sectional view of a toothed belt designed according to the invention in accordance with a second embodiment.

In Fig. 1, a traction drive of a bicycle 1 is schematically shown, which is designed according to the inven tion and uses a traction device having the features of the invention. The use of this timing belt is not limited to such or other vehicles, but can also in industrial applications, such as different types of Actuators, such as linear drives, door drives or drives for compressors and pumps.

The bicycle 1 has a frame 2 in a manner known per se, in which a steerable front wheel 3 and a drivable rear wheel 4 are each mounted in a rotating bar. A Zugmit telantriebsrad 5 is connected to the frame 2 via a bottom bracket, not shown.

The traction drive wheel 5 is rigidly connected to two pedal levers 6, 7, by means of which the traction drive wheel 5 can be set in rotation.

A hub of the rear wheel 4, which cannot be seen in FIG. 1, is operatively connected to a traction mechanism output wheel 8, the traction mechanism output wheel 8 being rigidly connected to the hub or indirectly connected to the hub via a hub switching device. Traction drive wheel 5 and traction drive 8 are connected to each other by a traction means 9. The traction drive wheel 5, the traction drive wheel 8 and the traction device 9 together form the traction drive 10. The traction device 9 is a toothed belt 11 and, accordingly, the traction drive wheel 5 and the traction drive wheel 8 each form a toothed pulley 12, 13. For the sake of clarity, the toothed belt is shown exaggeratedly thick in FIG. 1.

2, the traction mechanism drive 10 is shown in section along the section line A-A 'according to FIG. 1 in a partial view. The traction device 9 designed as a toothed belt 11 has, in a known manner, a belt body 14 made of an elastomeric material radially on the outside, in which thread-like reinforcement members 16 are arranged radially on the outside toward the top 15 of the belt. At the top 15 of the belt there are two side flanks 17, 18, which extend perpendicularly with respect to the top 15 of the belt and radially inward therefrom. The side flanks 17, 18, which are aligned parallel to one another, are axially spaced from one another, so that they form the belt width b in the area of the upper side 15 of the belt or in the area of the arrangement of the strength members 16.

Belt teeth 19 each adjoin the side flanks 17, 18 radially on the inside, of which only one belt tooth 19 is shown in FIG. 2. Two lateral tooth flanks 20, 21 of the belt tooth 19 end radially on the inside at a common tooth head 22, the Surface is aligned parallel to the top 15 of the belt and forms the radial inside of the toothed belt 11.

The traction drive wheel 8 designed as a toothed disk 13 has a disk base body 23 radially on the inside, through whose radial center, not shown in FIG. 2, the axis of rotation of the toothed disk 13 runs. Radially and axially outside two flanges 24, 25 are integrally formed on the base body 23. Inner side walls 26, 27 of the flanges 24, 25 have a course corresponding to the course of the side flanks 17, 18 of the toothed belt 11.

The course of the outboard walls 28, 29 of the flanges 24, 25 in the radial direction is also perpendicular with respect to the axis of rotation of the toothed disk 13, but they can also have a different course. The axial distance between the inner side walls 26, 27 corresponds to the belt width b in the exemplary embodiment. The inner side walls 26, 27 of the toothed pulley 13 are provided, at least in the region of the contact of the toothed belt 11, with a friction and noise-reducing coating, which is not shown in the drawing in FIG. 2.

On the outer diameter or radially on the outside, the flanges 24, 25 each have a run-in slope 30, 31 through which the flanges 24, 25 are widened axially outwards in a funnel-like manner. The inlet slopes 30, 31 serve to facilitate the entry of the toothed belt 11 into the toothed pulley 13. Accordingly, the inlet slopes 30, 31 serve to ensure that the toothed belt 11 threads itself self-centering into the toothed disk 13 and does not or only to an acceptable extent on the Flanged wheels 24, 25 runs up, which could damage the toothed belt 11.

The toothed disc 12 of the traction drive wheel 5 according to FIG. 1 is basically the same as the toothed disc 13 and differs from it only by a larger diameter.

Since it is not always guaranteed in the case of traction drives of bicycles by twisting of the frame that the two toothed disks 12, 13 are exactly aligned with one another, is a smooth running of the toothed belt 11 into the respective toothed pulley 13, 12 is not guaranteed under all circumstances. Therefore, according to the invention, the toothed belt 11 itself is provided with at least one run-in slope. In the exemplary embodiment according to FIG. 2, it is precisely a run-in slope 32 which is located on the right-hand side of the toothed belt 11 shown in FIG. 2 and radially below the right tooth flank 21.

The left side of the toothed belt 11 runs radially in a conventional manner, that is to say that the left tooth flank 20 extends perpendicular to the axis of rotation of the toothed pulley 13 as far as the tooth head 22 as an extension of the side flank 17. The right tooth flank 21 deviates from there also initially perpendicularly and in a straight line an imaginary plane 33 radially below half of the strength members 16. The height of this straight toothed segment 34 is noticeably lower than the total height hs2 of the belt tooth 19. A straight toothed wedge segment 35 connects seamlessly to the straight toothed segment 34 radially on the inside. This tooth wedge segment 35 is asymmetrical in cross section and has a height hsl, which is less than the total height hs2 of the belt tooth 19. While the left tooth flank 20 of the tooth wedge segment 35 runs radially straight in continuation of the left side flank 17, the right one Tooth flank 21 in the region of the toothed wedge segment 35 is provided with a toothed wedge flank 36 which opens into the tooth head 22 and which forms the run-in slope 32 of the toothed belt 11.

The tooth wedge flank 36 is oriented at a tooth flank angle ZFW of 5 ° to 45 °, preferably between 10 ° and 20 °, to the vertical defined by the two side flanks 20, 21 and by the straight tooth element 34. In the illustrated embodiment, the tooth flank angle ZFW is approximately 15 °.

Due to the run-in slope 32, a tooth width bZ of the tooth head 22 is less than the belt width b. The lead-in bevel 32 thus enables the toothed belt 11 to gently enter the respective toothed pulley 12, 13 even when the toothed pulleys 12, 13 are not aligned with one another. The reduced tooth width bZ of the belt tooth 22 is acceptable here and in no way reduces the functionality of the traction mechanism drive 10 Wise. The strength members of the toothed belt 11 are made of steel cord in the exemplary embodiment, but they can also consist of another suitable material, for example of aramid or carbon. The belt teeth 19 are provided in the region of the tooth flanks 20, 21 with a friction and noise-reducing coating not shown in FIG. 2, which in the exemplary embodiment consists of PTFE.

In Fig. 3 a second embodiment of a toothed belt 1 la is shown as a traction means of the traction drive 10 in cross section corresponding to that of FIG. 2, the same reference numerals being used for the same parts and components.

The right side of the toothed belt 1 la is formed exactly like the right side of the toothed belt 11 according to FIG. 2. Accordingly, the right tooth flank 21 initially also runs radially perpendicular and straight to the imaginary plane 33 below the mounting bracket 16. The height of this along the tooth flank 21 straight tooth segment 34a is less than the total height hs2 of the belt tooth 19a. The toothed wedge segment 35a connects seamlessly to the toothed segment 34a, which also extends radially perpendicular to the upper side 15 of the toothed belt 11. This toothed wedge segment 35a is also of asymmetrical cross-section, but different from the exemplary embodiment according to FIG. 2.

While the right tooth flank 21 of the tooth wedge segment 35a is also provided with a tooth wedge flank 36, which forms a run-in slope 32, the left tooth flank 20a of the tooth wedge segment 35a does not run straight as a continuation of the side flank 17a, but rather the entire left side or the left side flank 17a of the toothed belt 11a is formed into a run-in slope 32a. This entry slope 32a begins directly on the belt top 15 and extends at the same slope angle SW up to the tooth head 22a. The helix angle is between 5 ° and 45 °, preferably between 10 ° and 20 °. In the illustrated embodiment, the helix angle SW is approximately 25 °. The entry slope 32a extends recognizably over the entire belt height h.

In deviation from the exemplary embodiments according to FIGS. 2 and 3, the run-in slopes 32, 32a can also be formed symmetrically to one another. So a toothed belt on both sides of the same design in terms of height and Have angles of the run-in bevels, for example have a configuration on both sides which would correspond to the right side of the toothed belt 11 shown in FIG. 2, or a symmetrical configuration with run-in bevels 32a running through on both sides corresponding to the left side of the toothed belt 11a according to FIG. 3. Also within the scope of the invention are configurations with heights hsl of the inlet slopes, which are between 30% and 80% of the belt height h. Finally, it can be provided that the contour of the run-in bevels on the toothed belt is not straight, but has a curved course.

Reference symbol list

1 vehicle, bike

2 frames

3 front wheel

4 rear wheel

5 traction drive wheel

6 First pedal lever

7 Second pedal lever

8 traction drive wheel

9 traction means

10 traction drive

11 timing belts

11a timing belt

12 tooth lock washer

13 tooth lock washer

14 belt body

15 top of belt

16 reinforcements

17 side flank

17a side flank

18 side flank

19 Belt tooth

19a belt tooth

20 tooth flank

20a tooth flank

21 tooth flank

22 tooth head

23 disk base body

24 First flanged wheel

25 Second flanged wheel

26 First inner side wall 27 Second inner side wall

28 First outer side wall

29 Second outer side wall

30 lead-in slopes

31 entry slope

32 chamfer of the toothed belt 11, 11a

32a inlet slope of the toothed belt 11a

33 level below the reinforcement 16

34 Straight tooth segment

34a Straight tooth segment on one side

35 spline segment

35a wedge segment

36 tooth wedge flank

A-A ’cut line

b belt width

bZ tooth width

h height of the toothed belt 11, 11a hsl tooth wedge height of the toothed wedge segment 32 hs2 total height of the belt tooth 19, 19a

SW slope angle of the inlet slope 32a

ZFW tooth flank angle

Claims

1. traction means for a traction means drive (10), in which a traction means drive wheel (5) via a traction means (9) with a traction means driven wheel (8) is drive-connected, the Zugmit telantriebsrad (5) and the traction means driven wheel (8) each as a toothed disc (12 , 13) and the traction means (9) are designed as toothed belts (11; 11a) with a plurality of belt teeth (19; 19a), the toothed belt (11; 11a) having a belt body (14) in which thread-like strength members (16 ) are arranged, the belt body (14) having a belt top (15) radially on the outside, to which radially inwardly extending side flanks (17, 18) are connected, the two side flanks (17, 18) in the region of the belt top (15 ) have an axial distance from one another which forms the belt width (b), and in which a tooth flank (20, 21; 20a) of the belt teeth (19; 19a) adjoins the two side flanks (17, 18) radially on the inside, which adjoins one common tooth head (22; 22a), which is oriented parallel to the upper side of the belt (15) and forms the radial inside of the toothed belt (11; 11a), characterized in that at least one tooth flank (20; 21; 20a) of the respective belt teeth (19; 19a) has a tooth wedge flank (36) opening into the tooth head (22; 22a), which forms an entry slope (32; 32a) of the toothed belt (11; 11a), and that the tooth width (bZ) of the tooth head (22; 22a) is smaller than the belt width (b).

2. traction device according to claim 1, characterized in that the tooth flanks (20, 21; 20a) of the belt teeth (19; 19a) at least in a tooth wedge segment (35; 35a) opening into the tooth head (22) at a tooth flank angle (ZWF) are aligned with one another, which deviates from the alignment of at least one of the side flanks (17; 18) and is between 5 ° and 45 °, preferably between 10 ° and 20 °.

3. traction device according to claim 2, characterized in that the height (hsl) of the tooth wedge segment (35; 35a) is between 50% and 100%, preferably 80%, of the total height (hs2) of the belt tooth (19; 19a).

4. traction means according to one of claims 1 to 3, characterized in that the tooth flanks (20, 21) of the toothed belt (11) forming a straight toothed segment (34) extend radially inwards and in relation to an imaginary plane (33) below the strength carrier (16) runs vertically, this imaginary plane (33) geometrically separating the belt body (14) from the respective toothed segment (34), and that the beveled toothed wedge segment (35) adjoins this straight toothed segment (34), where the height of the straight tooth segment (34) is less than the total height (hs2) of the belt tooth (19).

5. traction means at least according to claim 2, characterized in that the belt teeth (19; 19a) are asymmetrical, the opposite tooth flanks (20; 20a; 21) are aligned in different tooth flank angles or helix angles (ZFW; SW).

6. Traction device according to one of claims 1 to 5, characterized in that the tooth flanks (20, 21; 20a, 21a) are provided with a friction and noise-reducing coating.

7. traction device according to one of claims 1 to 6, characterized in that at least one entire side flank (17a) of the toothed belt (11a) is formed into a run-in slope (32a) which begins at the top of the belt (15) and is at a constant slope angle (SW) extends to the tooth head (22a) over the entire belt height (h).

8. traction device according to claim 7, characterized in that the inclined angle (SW) is between 5 ° and 45 °, preferably between 10 ° and 20 °.

9. traction means at least according to claim 1, characterized in that the belt teeth (19; 19a) are symmetrical, the opposing tooth flanks (20; 20a; 21) are aligned at the same tooth flank angle (ZFW; SW) or with the same in Tooth flank angle (ZFW) or bevel angle (SW) led heights (h; hs2; hsl) and are each provided with an identical bevel (32; 32a).

10. traction drive (10) with a traction means (9) according to at least one of the preceding claims, characterized in that inner side walls (26, 27) of the flanges (24, 25) at least one toothed washer (12, 13) at least in the area of the system Toothed belts (11, 11a) are provided with a friction and noise-reducing coating.

11. traction mechanism drive (10) according to claim 10, characterized in that the toothed disks ben (12, 13) axially on both sides each have flanges (24, 25) with radially outer inlet bevels (30, 31).

12. Use of the traction drive (10) with the features of claim 10 or claim 11 in a vehicle.

13. Use of the traction drive (10) with the features of claim 10 or claim 11 in a bicycle (1).

14. Use of the traction drive (10) with the features of claim 10 or claim 11 in finear drives, door drives or drives for compressors and pumps.