DE102019111102A1 - Traction drive - Google Patents

Abstract

Traction drive with an endless traction means for transferring drive power, from a first drive wheel to a second drive wheel, this endless traction means for power transmission contacting both this first and this second drive wheel and moving in one direction of movement during the power transmission and the endless traction means forming one Load side and a slack side, characterized in that
the traction drive has a first pressing device and
that the first pressing device contacts the traction means in the direction of movement of the traction means simultaneously with the first drive wheel or in front of the first drive wheel
and
that the endless traction means in the load strand between the first and the second drive wheel runs at least substantially along a straight line and
that at least one first and one second deflection roller are provided which contact this endless traction means in the empty tower and that these two deflection rollers are arranged in the direction of movement of the traction means after the first drive wheel and in front of the second drive wheel.

Description

The invention relates to a traction drive according to the preamble of the first claim. A traction drive according to the preamble of the first claim is known from the prior art, in particular from US Pat DE 10 2014 015 156 A1 .

The invention is described below on the basis of a traction drive in the form of a chain drive; this is not to be understood as a limitation of the invention. It is known that in a chain transmission, part of the friction during the power transmission by means of the chain leads to losses. These losses can arise from the fact that the chain is deformed from the curved state to the straight state under load, for example when revolving around a sprocket and especially in the load side, the same applies to the reverse movement. In general, such losses are caused when the loaded chain section runs up or down.

Against this background, it is an object of the invention to specify a traction mechanism drive with low power dissipation during power transmission. This object is achieved by a traction drive according to the first patent claim; preferred embodiments of the invention are the subject matter of the dependent claims.

A basic idea of the invention is therefore to avoid the endless traction means provided for power transmission from being deformed during the power transmission under load from the curved to the straight state or vice versa.

In the context of the invention, a traction drive is to be understood as a traction drive for transmitting drive power with an endless traction. The endless traction means is preferably designed as a form-fitting traction means, preferably as a toothed or ribbed belt and particularly preferably as a chain.

A chain is preferably designed as a roller chain and particularly preferably as a so-called O-ring chain. More preferably, such a chain has a friction-reducing coating. Such a traction mechanism drive is used in particular in a motorcycle drive, that is to say in particular for driving the rear wheel of the motorcycle.

To transmit the drive power, the traction drive has a first drive wheel, which can preferably be driven by a drive machine, and a second drive wheel to which the drive power, in particular provided by the drive machine, can be transmitted with the endless traction means. In the sense of a motorcycle drive, the first drive wheel would be coupled or can be coupled to an internal combustion engine and the second drive wheel would be coupled or coupled to the rear wheel. Accordingly, the first and the second drive wheel are contacted by the endless traction means for power transmission and the endless traction means continues to move in one direction of movement during the power transmission from the first to the second drive wheel.

In the prior art, it is customary to designate that section which is provided for power transmission (preferably tensile or compressive stress) as the load strand and that section of the endless traction means which is moved almost without tension as the slack strand or, figuratively speaking, the load strand or tensile strand is the side the endless traction device (chain, rope or belt), which is pulled and is taut and a slack strand is the loose, not pulled and sagging strand.

Furthermore, the traction mechanism drive has a first pressing device which is set up to achieve reliable contact between the endless traction mechanism and the first drive wheel during the power transmission. In order to achieve reliable contact with the first drive wheel, the first pressure device makes contact with the traction means in the direction of movement of the traction means during power transmission at the same time as the first drive wheel or in front of the first drive wheel. In particular, the first pressing device makes it possible to keep a contact area between the first drive wheel and the endless traction means small; this contact area can also be understood as a wrap angle or can be described by means of such an angle.

More preferably, the endless traction mechanism also contacts the second drive wheel and, during the power transmission between the first and the second drive wheel, in particular in the load side, runs at least substantially along a straight line. At least essentially along a straight line refers in particular to the fact that, due to the mechanical relationships, there is always a certain sagging of the endless traction mechanism, or that there may be slight deviations from a straight line due to vibrations of the endless traction mechanism during power transmission. The endless traction means preferably runs without deflection in the load strand. In particular, through this configuration of the traction mechanism drive, it can be achieved that the endless traction mechanism is not deflected in the load side and this results in a low power loss.

The traction mechanism drive also preferably has a first and a second deflection roller, which contact this endless traction mechanism in the empty tower. In this case, these two deflection rollers are thus arranged in such a way that they are arranged in the direction of movement of the traction means after the first drive wheel and in front of the second drive wheel. And further preferably, at least the first deflection roller is designed to reduce the contact area between the endless traction means and the first drive wheel.

In a preferred embodiment of the traction mechanism drive, the endless traction mechanism contacts the first drive wheel along a first contact section. Furthermore, in this embodiment of the invention, the first deflection roller is arranged such that this first contact section is smaller than 45 °, so preferably a first wrap angle of the endless traction means around the first drive wheel is smaller than 45 °. The first contact section is preferably smaller than 30 ° and preferably smaller than 15 ° and particularly preferably the first contact section is smaller than 5 °. Further preferably, the endless traction means runs in the direction of movement of the traction means between the first drive wheel and the first deflection roller at least essentially along a straight line. In particular, such a configuration of the traction mechanism drive means that the endless traction mechanism is not deflected on or by the first drive wheel, but rather by the first deflection roller. In contrast to the first drive wheel, a particularly low-loss deflection is made possible on the first deflection roller, which is arranged in the slack strand of the endless traction mechanism as explained, and a traction mechanism drive with high efficiency can thus be achieved.

In a preferred embodiment of the invention, at least one further deflection roller is provided. Further preferably, this at least one further deflection roller is arranged in the direction of movement of the endless traction means after the second deflection roller and in front of the second drive wheel, and this further deflection roller preferably contacts the endless traction means in the slack strand. Preferably, several further deflection rollers are provided, preferably exactly three deflection rollers are provided and particularly preferably exactly 4 deflection rollers are provided.

In a preferred embodiment, the endless traction means contacts the second drive wheel along a second contact section; figuratively speaking, the endless traction means wraps around the second drive wheel with a second wrap angle. Furthermore, the at least one further deflection roller is preferably arranged in such a way that this second contact section or this second wrap angle is smaller than 45 °. The second contact section is preferably smaller than 30 ° and preferably smaller than 15 ° and particularly preferably the second contact section is smaller than 5 °. Further preferably, the further deflection roller is arranged such that the endless traction means runs in the direction of movement of the traction means between the further deflection roller and the second drive wheel at least essentially along a straight line. In particular, through such an embodiment of the traction mechanism drive, the endless traction mechanism only revolves around the second drive wheel with a small second wrap angle, and thus a low degree of loss in power transmission can be achieved.

In a preferred embodiment of the traction mechanism drive, a second pressing device is provided. Furthermore, this second pressing device is preferably designed in such a way that the endless traction means is contacted by the second pressing device in the load strand. The second pressing device is preferably arranged in such a way that it contacts the traction device in the direction of movement of the traction device at the same time as the second drive wheel or after the second drive wheel and in any case before the first pressing device. The traction means preferably runs between the second drive wheel and the second pressing device, at least essentially, along a straight line. Furthermore, the second pressing device is preferably set up to ensure reliable contact between the endless traction means and the second drive wheel.

Preferably at least one or both pressure devices has a pressure roller for contacting the endless traction means. Such a pressure roller is preferably designed as a chain wheel and preferably as a cylindrical roller, ie preferably as a pressure roller without toothing. Preferably, at least one of the two pressure rollers or these two pressure rollers are not arranged symmetrically to the first / second drive wheel with respect to the endless traction mechanism and these are then designed either as a pressure roller with (chain wheel) or as a pressure roller without teeth. Otherwise (symmetrical arrangement of the two pressure rollers to the first / second drive wheel) these are designed as pressure rollers without teeth. The pressure rollers ensure the engagement of the two drive wheels in the endless traction means, which is preferably designed as a roller chain.

Preferably, at least one of the deflection rollers or several of these deflection rollers is designed as a chain wheel. Further preferably, at least one of these deflection rollers or several of the deflection rollers are designed without a toothing and preferably in such a way that this deflection roller or deflection rollers on rollers, one especially designed as a roller chain endless traction means, and thus run without teeth.

In a preferred embodiment of the invention, at least one of the deflection rollers is designed as a tensioning roller. Such a tensioning roller is preferably movable in such a way that it impresses a predeterminable tension on the endless traction mechanism. Tensioning rollers as such are known from the prior art in traction mechanism drives.

• 1: zeigt eine erste Ausführungsform der Erfindung mit vier Umlenkrollen,
• 2: zeigt eine zweite Ausführungsform der Erfindung mit vier Umlenkrollen,
• 3: zeigt eine dritte Ausführungsform der Erfindung mit drei Umlenkrollen.

In a preferred embodiment, the traction means is designed as a form-fitting traction means. The traction mechanism drive is also preferably designed as a drive device for a rear wheel of a single-track vehicle, preferably as a motorcycle drive device.

• 1 : shows a first embodiment of the invention with four pulleys,
• 2 : shows a second embodiment of the invention with four pulleys,
• 3 : shows a third embodiment of the invention with three pulleys.

In Figure one is a first embodiment of the invention with four swivel castors ( 6th , 7th , 8th , 9 ) shown. The endless traction device 1 is designed as an O-ring chain. The traction mechanism drive shown also has two pressure devices, each of which is the first pressure roller 4th and the second pressure roller 5 are shown. There are the first and second pressure rollers 4th , 5 arranged in such a way that these are each simultaneously with the first drive wheel 2 and the second drive wheel 3 the endless traction means 1 to contact.

In the load side 12th the endless traction mechanism runs 1 straight forward. In contrast to a conventional traction mechanism, the traction mechanism is endless 1 not through the first drive wheel 2 deflected but according to the invention runs in a straight line starting from the first drive wheel 2 after leaving the first contact section 14th straight ahead to the first pulley 6th . From the first pulley 6th becomes the endless traction mechanism 1 towards the second pulley 7th deflected, both the first pulley are located 6th as well as the second pulley 7th , in the empty run 13 . Starting from the second pulley 7th the endless traction mechanism runs 1 by two more pulleys (third pulley 8th , fourth pulley 9 ) before starting from the fourth pulley 9 straight into the second contact section 15th on the second drive wheel 3 running. The second pressure roller 5 contacts the endless traction mechanism 1 simultaneously with this second drive wheel 3 . It can be clearly seen that in the load side 12th , which between the first contact area 14th and the second contact area 15th lies, no deflection of the endless traction device under tension there 1 takes place and thus the endless traction mechanism 1 digit only in the unloaded slack side 13 by means of the pulley 6th to 9 is diverted. In particular through this distribution of the deflection of the endless traction mechanism 1 completely or at least almost completely in the slack strand 13 a particularly low-loss traction drive can be shown. Since, in particular, the angle of oscillation of the endless traction mechanism 1 around the drive wheels 2 , 3 is low, set the two pressure rollers 4th , 5 a safe power transmission between the endless traction mechanism 1 and these two drive wheels 2 , 3 for sure.

In 2 an embodiment of the invention that is slightly modified compared to the embodiment of the invention shown in FIG. The following description mainly focuses on the differences in 2 illustrated embodiment of the invention compared to the in 1 shown embodiment received. The two pressure rollers 4th , 5 are in the load strand 12th moved so that this is the endless traction device 1 no longer simultaneously with the first or second drive wheel ( 2 , 3 ) but before or after these drive wheels.

In 3 a further embodiment of the invention is shown, the differences between this embodiment and the embodiments shown in the previous figures are essentially discussed. In the 3 The illustrated embodiment of the invention has only a single further deflection roller (third deflection roller 8th ), namely the third pulley 8th on. From this another pulley 8th , the endless traction mechanism runs 1 straight into the second contact section 15th . The pressure rollers 4th , 5 are like in the in 1 illustrated embodiment of the invention arranged.

• - die Umlenkrollen sind der Art angeordnet, dass diese sicherstellen, dass die Kette ab Last-Aufnahme bzw. bis zur Lastabgabe nicht mehr gekrümmt wird,
• - die Andrückrollen sind der Art angeordnet, dass die Kette bei Last-Aufnahme bzw. Last-Abgabe in Eingriff bleibt,
• - eine der Umlenkrollen ist gleichzeitig als Spannrolle ausgebildet,
• - wenigstens eine der Umlenkrollen oder mehrere dieser können in einer Ausführungsform der Erfindung auch nicht als Kettenrad ausgebildet sein, die Umlenkrollen können in diesem Fall der Art ausgebildet sein, dass diese auf Rollen eines als Rollenkette ausgebildeten endlos Zugmittels laufen,
• - wenigstens zwei der Andrückrollen können in einer Ausführungsform der Erfindung bezüglich des endlos Zugmittels nicht symmetrisch zum ersten/zweiten Antriebsrad angeordnet sein, diese können entweder als Rolle oder als Kettenrad ausgeführt sein. Andernfalls (symmetrische Anordnung) können diese als Rolle ausgeführt sein und stellen den Eingriff der Rollen einer Rollenkette in die Verzahnung von erstem/zweiten Antriebsrad sicher.

In other words, individual embodiments of the invention provide at least one of the following features or several of these features:

• - The deflection pulleys are arranged in such a way that they ensure that the chain is no longer bent from the point at which the load is picked up or until the load is transferred,
• - the pressure rollers are arranged in such a way that the chain remains in engagement when the load is picked up or released,
• - one of the pulleys is also designed as a tension pulley,
• - At least one of the deflection rollers or several of these can also not be designed as a chain wheel in one embodiment of the invention; the deflection rollers in this case can be designed in such a way that they are on rollers of a endless traction means designed as a roller chain run,
• In one embodiment of the invention, at least two of the pressure rollers can not be arranged symmetrically to the first / second drive wheel with respect to the endless traction means; Otherwise (symmetrical arrangement) these can be designed as a roller and ensure the engagement of the rollers of a roller chain in the toothing of the first / second drive wheel.

With the proposed invention, in particular, a traction mechanism drive with reduced frictional power can be achieved; in particular, when using such a drive as a motorcycle drive, more drive power can be delivered to the driven rear wheel or a higher degree of efficiency can be achieved.

List of reference symbols

1

endless traction mechanism

2

first drive wheel

3

second drive wheel

4th

first pressure roller

5

second pressure roller

6th

first pulley

7th

second pulley

8th

third pulley

9

fourth pulley

10

Drive direction of rotation

11

Direction of movement from 1

12

Load strand

13

Empty run

14th

first contact section

15th

second contact section

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely 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 102014015156 A1 [0001]

Claims (7)

Traction drive with an endless traction means (1) for transmitting drive power, from a first drive wheel (2) to a second drive wheel (3), this endless traction means (1) for power transmission both this first and this second drive wheel (2, 3) contacted and moves in a direction of movement (11) during the power transmission and the endless traction means (1) forms a load strand (12) and a slack strand (13), characterized in that the traction mechanism drive has a first pressing device (4) and that the first pressing device (4) contacts the traction means (1) in the direction of movement (11) of the traction means simultaneously with the first drive wheel (2) or in front of the first drive wheel (2) and that the endless traction means (1) in the load strand (12) between the first and second drive wheels (2, 3) run at least substantially along a straight line and that at least one first and one second deflection roller (6, 7) are provided, which e Contact the traction means (1) in the empty tower (12) and that these two pulleys (6, 7) are arranged in the direction of movement (11) of the traction means after the first drive wheel (2) and in front of the second drive wheel (3). Traction drive according to Claim 1 , characterized in that the endless traction means (1) contacts the first drive wheel (2) along a first contact section (14), that the first deflection roller (6) is arranged such that this first contact section (14) is smaller than 45 ° and that the endless traction means (1) runs in the direction of movement of the traction means between the first drive wheel (2) and the first deflection roller (6) at least essentially along a straight line. Traction drive according to one of the preceding claims, characterized in that at least one further deflection roller (8) is provided, that this at least one further deflection roller (8) in the direction of movement (11) of the endless traction device (1) after the second deflection roller (7) and before the second drive wheel (3) is arranged and that this further deflection roller (8) contacts the endless traction means (1) in the slack strand (13). Traction drive according to Claim 3 , characterized in that the endless traction means (1) contacts the second drive wheel (3) along a second contact section (15), that the at least one further deflection roller (8) is arranged such that this second contact section (15) is smaller than 45 ° and that the endless traction means (1) runs in the direction of movement (11) of the traction means between the further deflection roller (8) and the second drive wheel (3) at least essentially along a straight line. Traction drive according to one of the preceding claims, characterized in that a second pressure device (5) is provided and that the endless traction device (1) in the load strand (12) is contacted by the second pressure device (5) and that the second pressure device (5) in Direction of movement (11) of the traction mechanism contacts the traction mechanism (1) simultaneously with the second drive wheel (3) or after the second drive wheel (3) and in any case before the first pressing device (4) and that the traction mechanism (1) is between the second drive wheel (3 ) and the second pressing device (5) runs at least substantially along a straight line. Drive device according to one of the preceding claims, characterized in that at least one of the deflection rollers (6-9) is designed as a tensioning roller. Drive device according to one of the preceding claims, characterized in that the traction means is designed as a form-fitting traction means.

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