DE102018220416A1 - Traction device for a traction drive - Google Patents

Abstract

The invention relates to a traction mechanism for a traction mechanism drive (10), in which a traction mechanism drive wheel (5) is drive-connected to a traction mechanism output wheel (8) via a traction mechanism (9). The traction drive wheel (5) and the traction drive wheel (8) are each designed as a toothed pulley (12, 13) and the traction device (9) as a toothed belt (11). The toothed belt (11) has a belt body (14) in which strength members (16) are arranged. A belt top (15) is adjoined by radially inwardly extending side flanks (17, 18), the spacing of which on the belt top (15) forms the belt width (b). A tooth flank (20, 21) of the belt teeth (19) adjoins the two side flanks (17, 18) radially on the inside, which end radially on the inside on a common tooth head (22). In order to be able to compensate for misalignments between the toothed pulleys (12, 13), 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 head (22) and which has a run-in slope (32) of the toothed belt (11), and that the tooth width (bZ) of the tooth head (22) is smaller than the belt width (b). The invention also relates to the use of this traction device and a traction device drive (10) equipped with it in industrial applications and on a vehicle.

Description

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 with a plurality of belt teeth, the toothed belt having a belt body , in which thread-like reinforcements are arranged, the belt body having a belt top radially on the outside, to which radially inwardly extending side flanks are connected, the two side flanks in the area of the belt top having an axial distance from one another which forms the belt width, and in which the A tooth flank of the belt teeth adjoins both 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. Related industrial applications are, for example, different types of actuators, such as linear drives, door drives or drives for compressors and pumps. Such traction mechanism drives are used in vehicles, for example in two-wheeled vehicles, such as motorcycles and bicycles. 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 connected via a continuous 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 retensioned. In addition, chains tend to rattle and harbor the risk of soiling the driver's clothing.

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

Compared to chains as traction devices, toothed belts have the advantage that they do not elongate, or at least only to a small extent, are lighter and function practically noiselessly during operation. For example, when using such a traction mechanism drive on a bicycle, however, special problems arise which are caused by the comparatively strong twisting 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, despite the inclined entry of the flanges of the toothed pulleys, runs onto the flanges and tears, 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 lock washer and a jumping off of the pulling device from the lock washer is excluded. After all, this traction drive should be usable in all types of industrial applications and vehicles.

This object is achieved by a traction device with the features of claim 1. A further independent patent claim relates to a traction device drive which is equipped with a traction device according to the invention. Advantageous further developments are defined in the dependent claims. Claims 12 to 14 indicate advantageous uses of the traction drive according to the invention.

The invention accordingly 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 toothed pulleys and the traction mechanism being designed as a toothed belt with a plurality of belt teeth, the toothed belt being a belt body has, in which thread-like reinforcements are arranged, the belt body having a belt top radially on the outside, to which radially inwardly extending side flanks connect, the two side flanks in the area of the belt top having an axial distance from one another which forms the belt width, and in which the two side flanks radially inside each have a tooth flank of the belt teeth, 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.

To solve the problem, this traction device provides that at least one Tooth flank of the respective belt teeth has a tooth wedge flank opening 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 finding that the object can be achieved 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.

It can also be provided that the tooth flanks of the belt teeth are aligned with one another at least in a tooth wedge segment opening into the tooth head at a tooth flank angle which deviates from the alignment 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 adjoins 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 opposite tooth flanks being oriented at 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 °.

As an alternative to this, it can be provided that the belt teeth are symmetrical, the opposing tooth flanks being aligned at the same tooth flank angle or having the same heights guided in the tooth flank angle or helical angle and each being provided with an identical trained 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.

• 1 ein Ausführungsbeispiel eines Zugmittelantriebes eines Fahrrades von der Seite gesehen,
• 2 den Zugmittelantrieb im Querschnitt entlang der Linie A-A' gemäß 1 in einer Teilansicht, und
• 3 eine Querschnittansicht eines erfindungsgemäß ausgebildeten Zahnriemens gemäß einer zweiten Ausführungsform.

Further features, advantages and details of the invention are described in more detail with reference to the attached 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,
• 2nd the traction drive in cross section along the line A-A ' according to 1 in a partial view, and
• 3rd a cross-sectional view of a toothed belt designed according to the invention according to a second embodiment.

In 1 is schematically a traction drive of a bicycle 1 shown, which is designed according to the invention 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 bike 1 has a frame in a manner known per se 2nd on, each of which rotates a steerable front wheel 3rd and a drivable rear wheel 4th are stored. A traction drive wheel 5 is over a bottom bracket with the frame, not shown 2nd connected. The traction drive wheel 5 is rigid with two pedal levers 6 , 7 connected through which the traction drive wheel 5 can be rotated.

One in 1 not recognizable hub of the rear wheel 4th is with a traction drive wheel 8th operatively connected, the traction drive wheel 8th rigidly connected to the hub or indirectly connected to the hub via a hub switching device. Traction drive wheel 5 and traction drive wheel 8th are by a traction device 9 connected with each other. The traction drive wheel 5 , the traction drive wheel 8th and the traction device 9 together form the traction drive 10th . The traction device 9 is as a timing belt 11 and correspondingly are traction drive wheel 5 and traction drive wheel 8th each as a toothed washer 12 , 13 educated. The timing belt is in for clarification 1 shown exaggeratedly thick.

In 2nd is the traction drive 10th on average along the cutting line A-A ' according to 1 shown in a partial view. That as a timing belt 11 trained traction devices 9 has a belt body radially outside in a known manner 14 Made of an elastomeric material, in the radially outside to the top of the belt 15 towards thread-like reinforcements 16 are arranged. To the top of the belt 15 two side edges close 17th , 18th which is in relation to the top of the belt 15 extend vertically from this radially inwards. The side flanks aligned parallel to each other 17th , 18th are axially spaced from one another so that they are in the area of the top of the belt 15 or in the area of the arrangement of the strength members 16 the belt width b form.

On the side flanks 17th , 18th belt teeth close radially on the inside 19th of which in 2nd just a belt tooth 19th is shown. Two side tooth flanks 20th , 21st of the belt tooth 19th end radially inwards on a common tooth head 22 whose surface is parallel to the top of the belt 15 is aligned and the radial inside of the toothed belt 11 forms.

That as a tooth lock washer 13 trained traction drive wheel 8th has a disk base radially inside 23 on, by whose in 2nd Radial center, not shown, the axis of rotation of the toothed disc 13 runs. Radially and axially outside are two flanged wheels 24th , 25th on the disc base 23 molded. Interior side walls 26 , 27th of the flanged wheels 24th , 25th show the course of the side flanks 17th , 18th of the timing belt 11 corresponding course.

The course of outboard walls 28 , 29 of the flanged wheels 24th , 25th in the radial direction is also perpendicular with respect to the axis of rotation of the toothed disc 13 , but they can also have a different course. The axial distance between the inner side walls 26 , 27th corresponds to each other in the embodiment of the belt width b . The inner side walls 26 , 27th the tooth lock washer 13 are at least in the area of the toothed belt 11 are provided with a friction and noise reducing coating, which in 2nd is not shown in the drawing.

The flanged disks have an outer diameter or radially outside 24th , 25th one entry slope each 30th , 31 through which the flanged wheels 24th , 25th are expanded like a funnel axially outwards. The inlet slopes 30th , 31 serve to facilitate the running-in of the toothed belt 11 in the tooth lock washer 13 . Accordingly, the inlet slopes serve 30th , 31 to the timing belt 11 quasi self-centering in the tooth lock washer 13 threading and not or only to an acceptable extent on the flanged wheels 24th , 25th runs up, which damages the toothed belt 11 could lead.

The tooth lock washer 12 the traction drive wheel 5 according to 1 is basically the same as the lock washer 13 trained and differs from this only by a larger diameter.

Since it is not always guaranteed that the two toothed lock washers in the case of traction drives of bicycles due to twisting of the frame 12 , 13 Aligning each other exactly is a smooth running-in of the timing belt 11 into the respective tooth lock washer 13 , 12 not guaranteed under all circumstances. Therefore, according to the invention, the toothed belt 11 even provided with at least one entry slope. In the embodiment according to 2nd it’s exactly a run-in slope 32 which are on the in 2nd shown right side of the timing belt 11 and radially below the right tooth flank 21st located.

The left side of the timing belt 11 runs radially conventional, that is, the left tooth flank 20th runs in the extension of the side flank 17th perpendicular to the axis of rotation of the toothed disc 13 to the tooth head 22 . The right tooth flank 21st deviating from this, it also runs perpendicular and straight to an imaginary plane 33 radially below the reinforcement 16 . The height of this straight tooth segment 34 is noticeably less than the total height hs2 of the belt tooth 19th . The straight tooth segment 34 closes seamlessly radially on the inside a beveled wedge segment 35 at. This wedge segment 35 is asymmetrical in cross-section and has a height hs1 which is less than the total height hs2 of the belt tooth 19th . While the left tooth flank 20th of the wedge segment 35 in continuation of the left side flank 17th is the right tooth flank 21st in the area of the tooth wedge segment 35 with one in the tooth head 22 mouth wedge flank 36 provided which the inlet slope 32 of the timing belt 11 forms.

The tooth wedge flank 36 is at a tooth flank angle ZFW from 5 ° to 45 °, preferably between 10 ° and 20 °, through the two side flanks 20th , 21st and through the straight tooth element 34 defined perpendicular. In the illustrated embodiment, the tooth flank angle is ZFW about 15 °.

Through the inlet slope 32 is a tooth width bZ of the tooth head 22 less than the belt width b . The inlet slope 32 thus enables toothed washers that are not aligned with one another 12 , 13 a smooth running-in of the timing belt 11 into the respective tooth lock washer 12 , 13 . The reduced tooth width bZ of the belt tooth 22 is acceptable here and reduces the functionality of the traction drive 10th in no way.

The strength members of the timing belt 11 consist of steel cord in the exemplary embodiment, but they can also consist of another suitable material, for example aramid or carbon. The belt teeth 19th are in the area of the tooth flanks 20th , 21st with one in 2nd provided friction and noise-reducing coating, not shown in the drawing, which in the exemplary embodiment consists of PTFE.

In 3rd is a second embodiment of a timing belt 11a as a traction mechanism of the traction mechanism drive 10th in cross section corresponding to that of 2nd shown, the same reference numerals being used for the same parts and components.

The right side of the timing belt 11a is designed exactly like the right side of the toothed belt 11 according to 2nd . The right tooth flank runs accordingly 21st initially also radially perpendicular and straight to the imaginary plane 33 below the reinforcement 16 . The height of this along the tooth flank 21st straight tooth segment on one side 34a is less than the total height hs2 of the belt tooth 19a . On the radially perpendicular to the top 15 of the timing belt 11 trending tooth segment 34a the spline segment closes seamlessly 35a at. This wedge segment 35a is also designed asymmetrically in cross section, but different from the embodiment according to 2nd .

While the right tooth flank 21st of the wedge segment 35a also with a tooth wedge flank 36 is provided, which is an inlet slope 32 forms, the left tooth flank runs 20a of the wedge segment 35a not in continuation of the side flank 17a straight, but the entire left side or the left side flank 17a of the timing belt 11a is at an entry slope 32a shaped. This entry slope 32a starts directly on the top of the belt 15 and extends at the same helix angle SW 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 is SW about 25 °. The inlet slope 32a extends visibly over the entire belt height H .

In deviation from the exemplary embodiments according to the 2nd and 3rd can the inlet slopes 32 , 32a also be symmetrical to each other. For example, a toothed belt can have the same configuration on both sides with regard to the height and angle of the inlet bevels, for example a configuration on both sides which is the 2nd shown right side of the timing belt 11 would correspond, or a symmetrical design with a continuous bevel on both sides 32a corresponding to the left side of the timing belt 11a according to 3rd . Embodiments with heights are also within the scope of the invention hs1 of the chamfers, which are between 30% and 80% of the belt height H be. 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, bicycle

2nd

frame

3rd

Front wheel

4th

Rear wheel

5

Traction drive wheel

6

First pedal lever

7

Second pedal lever

8th

Traction drive wheel

9

Traction means

10th

Traction drive

11

Timing belt

11a

Timing belt

12

Tooth lock washer

13

Tooth lock washer

14

Belt body

15

Top of the belt

16

Reinforcement

17th

Side flank

17a

Side flank

18th

Side flank

19th

Belt tooth

19a

Belt tooth

20th

Tooth flank

20a

Tooth flank

21st

Tooth flank

22

Tooth head

23

Disk base body

24th

First flanged wheel

25th

Second flanged wheel

26

First inner side wall

27th

Second inner side wall

28

First outer side wall

29

Second outer side wall

30th

Entry slope

31

Entry slope

32

Inlet slope 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

Tooth wedge segment

35a

Tooth wedge segment

36

Tooth wedge flank

A-A '

Cutting line

b

Belt width

bZ

Tooth width

H

Height of the timing belt 11 , 11a

hs1

Tooth wedge height of the tooth wedge segment 32

hs2

Total height of the belt tooth 19th , 19a

SW

Bevel angle of the inlet slope 32a

ZFW

Tooth flank angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 3629789 C2 [0003]

Claims (14)

Traction means for a traction means drive (10), in which a traction means drive wheel (5) is drive-connected via a traction means (9) to a traction means output wheel (8), the traction means drive wheel (5) and the traction means output 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 , wherein the belt body (14) has a belt top (15) radially on the outside, to which radially inward extending side flanks (17, 18) are connected, the two side flanks (17, 18) in the area of the belt top (15) joining one another Belt width (b) have an axial distance, and in each case a tooth flank (20, 21; 20a) of the belt teeth (19; 19a) adjoins the two side flanks (17, 18) radially on the inside, which tooth flank (19; 19a) connects to a common tooth head (22 ; 22a) ends, which is aligned parallel to the upper side of the belt (15) and 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 has an inlet 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). Traction means to Claim 1 , characterized in that the tooth flanks (20, 21; 20a) of the belt teeth (19; 19a) are aligned with one another at least in a toothed wedge segment (35; 35a) opening into the tooth head (22) at a tooth flank angle (ZWF) which is different from that Alignment of at least one of the side flanks (17; 18) deviates and is between 5 ° and 45 °, preferably between 10 ° and 20 °. Traction means to Claim 2 , characterized in that the height (hs1) of the toothed wedge segment (35; 35a) is between 50% and 100%, preferably 80%, of the total height (hs2) of the belt tooth (19; 19a). Traction device according to one of the Claims 1 to 3rd , characterized in that the tooth flanks (20, 21) of the toothed belt (11), forming a straight toothed segment (34), extend radially inward and run perpendicularly with respect to an imaginary plane (33) below the strength members (16), these imaginary plane (33) geometrically separates the belt body (14) from the respective toothed segment (34), and that the beveled toothed wedge segment (35) connects to this straight toothed segment (34), the height of the straight toothed segment (34) being lower than the total height (hs2) of the belt tooth (19). Traction means at least after Claim 2 , characterized in that the belt teeth (19; 19a) are asymmetrical, the opposite tooth flanks (20; 20a; 21) being aligned at different tooth flank angles or bevel angles (ZFW; SW). Traction device according to one of the Claims 1 to 5 , characterized in that the tooth flanks (20, 21; 20a, 21a) are provided with a friction and noise-reducing coating. Traction device according to one of the 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 extends to the tooth head (22a) at a constant slope angle (SW) entire belt height (h). Traction means to Claim 7 , characterized in that the helix angle (SW) is between 5 ° and 45 °, preferably between 10 ° and 20 °. Traction means at least after Claim 1 , characterized in that the belt teeth (19; 19a) are symmetrical, the opposing tooth flanks (20; 20a; 21) being aligned at the same tooth flank angle (ZFW; SW) or with the same tooth flank angle (ZFW) or helical angle ( SW) guided heights (h; hs2; hs1) and each with an identically designed inlet slope (32; 32a). 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 flanged wheels (24, 25) of at least one toothed pulley (12, 13) at least in the area of the toothed belt ( 11, 11a) are provided with a friction and noise-reducing coating. Traction drive (10) after Claim 10 , characterized in that the toothed disks (12, 13) each have flanges (24, 25) axially on both sides with radially outwardly arranged run-in slopes (30, 31). Use of the traction drive (10) with the features of Claim 10 or Claim 11 in a vehicle. Use of the traction drive (10) with the features of Claim 10 or Claim 11 with a bicycle (1). Use of the traction drive (10) with the features of Claim 10 or Claim 11 for linear drives, door drives or drives for compressors and pumps.

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