DE102007016007A1 - Automatic clamping system for use in internal combustion engine of motor vehicle, has spreading unit formed as auxiliary aid arranged between housing part and arm that is spaced in mounting position opposite to part - Google Patents

Abstract

The system has a clamping arm (1) pivoted at a machine part over a housing part, where the arm is provided with a clamping roller (2) for supporting in a traction mechanism. A damping unit (10) damps clamping arm movements, and a path limit (23) includes clamping arm-sided and housing part-sided limitation units (5, 7, 8) for limiting a maximum operating area (6) of the arm. A spreading unit i.e. spring element, is formed as an auxiliary aid that is arranged between a housing part (3) and the arm that is axially spaced in a mounting position opposite to the housing part. An independent claim is also included for a method for assembling an automatic clamping system for a traction mechanism drive for use in internal combustion engines of motor vehicle.

Description

Name of the invention

automatically Clamping system for a traction drive and method for Assembly of such a clamping system

Field of the invention

The The invention relates to an automatic clamping system for a traction drive, for example for use on internal combustion engines of motor vehicles, comprising one about a housing part on a machine part rotatably storable clamping arm with at least a tensioning roller for supporting on a traction means, a used in the housing part, with a torque the tension arm effective torsion spring to produce a continuous Preload of the traction device, a damping unit for damping von Spannarmbewegungen, as well as a Wegbegrenzung with corresponding clamping arm side and housing part-side limiting means to limit a maximum working range of the clamping arm. The invention further relates to a method of assembling such a clamping system.

Background of the invention

flexible drives, In particular, belt drives for driving auxiliary units, for example generators, Fans, compressors and pumps, on internal combustion engines in Motor vehicles need to avoid hitting or belt slipping a certain belt pretension. Basically also need chain drives with Sprockets and positive toothed belt drives a certain bias to a flawless and quiet To ensure running behavior. To over the entire Life of the traction mechanism drive as uniform as possible bias Maintaining automatic clamping systems are usually used. Such clamping systems are mechanical or hydraulic devices realized in many ways and for a long time known.

at a common construction of mechanical belt tensioner is pivotable on the crankcase of the internal combustion engine slidably mounted clamping arm, which carries a tension roller, which is spring-loaded on the belt, wherein the clamping arm over a torsion spring is acted upon by a torque. The tensioner transfers one pre-tension set during assembly on the belt and holds this by a corresponding pivoting of the lever in operation upright. Unlike manual clamping devices is thus an adjustment of the tensioning arm or tensioning roller is not required.

Farther A damping unit is mandatory for vibrations and shocks from the internal combustion engine, transmit the driven units and the belt drive itself be dampened to minimize wear and tear on and to enable low-noise and storage-friendly operation.

modern Traction drives, in a common drive, for example via particularly flexible V-ribbed belts, power several units, are subject to increasingly high tensile and bearing loads. Corresponding the demands on the automatic clamping units increase Function and service life. Increasingly, due to larger and additional aggregates as well as by design specifications of limited space available. additionally especially for energy saving reasons and for Good driving dynamics generally the lowest possible Weight of components installed in vehicles, including the Clamping systems required.

This makes a constant development of traction drives for vehicles necessary. The DE 42 20 879 A1 and EP 0 780 597 B1 For example, show improvements in terms of relief of storage, while the DE 43 00 178 C1 and the DE 601 05 759 T2 aimed at a permanently consistent damping effect or a more effective damping mechanism.

Use some clamping systems, such as in the DE 100 55 594 A1 shown, as a damping unit with a rotatably connected to the clamping arm, axially loaded friction disc, which cooperates with a surface of a corresponding friction lining on a stationary housing part to produce a Spanarmbewegungen the opposing friction torque. To achieve the required friction work such Reibscheibenspanneinheiten require a relatively high axial force, which usually has to be applied by a correspondingly large dimensioned Axialkraftkomponente designed as a helical spring torsion spring.

Other clamping systems separate the torsional moment and the axial force. In the DE 103 28 900 A1 For example, a torsion spring is used to generate the torsional moment. For axial contact pressure of a friction disc, an additional compression spring is provided.

Furthermore, various clamping systems are known, the damping function is realized by a arranged on the sliding bearing of the clamping arm friction sleeve instead of a friction disc. Particularly compact build so-called Konusspann systems with conical friction liners used as plain bearings. The DE 101 52 364 A1 shows, for example, such a clamping unit in which is used to achieve a required contact force on the conical friction bushing a conically wound, adapted to the friction bushing helical torsion spring. Another conical friction bushing on a clamping system shows the DE 10 2004 028 485 A1 ,

A Applicant's new generation of tensioning systems uses torsion springs, the only relatively low axial forces during operation because their damping units are designed so that they are contrary to the conventional clamping systems no high axial force required to achieve the friction work need. The friction work can with these clamping systems at least predominantly via radially effective friction linings be generated. To compensate for axial tolerances is also usually provided an axial bearing. Accordingly is the torsional moment of the torsion spring only a relatively small Axialkraft superimposed, so that in principle space-saving cost Torsion springs are used with low axial force component can.

there However, there is a mounting problem by a conventional Way arranged Wegbegrenzung that a pivot or work area of Clamping arm limited. For this purpose, a projection of the stationary housing engages axially in a window of the clamping arm, that of two end stops is limited. The tensioning arm can be within the specified working range pivot, the end stops, if necessary Striking (snapping) to withstand the shear forces occurring have to. This is done by one, taking into account the material of the limiting elements, for example aluminum die casting, certain, sufficiently dimensioned axial overlap ensured by projection and end stop.

to Assembly of the clamping system must first clamping arm and housing part according to the overlap of the Travel limit relative to each other at least as far raised that a relative rotation for the purpose of biasing the torsion spring can take place without the boundary elements with each other in collision. Only then is an axial Translation, in which the clamping arm and the housing part completely put together as well as the lead engages with the bounding window.

at conventional clamping systems is the mentioned Raising of clamping arm or housing part over the anyway sufficiently large axial force spring rate in the Usually applied as a helical compression spring torsion spring applied. In the new clamping systems described above, the axial spring rate the torsion spring but this insufficient, so that the torsion spring for assembly reasons, in particular to ensure a Mounting with automatic mounting equipment, with a higher spring rate must be designed than this to their Operation function would actually be necessary. this in turn leads to larger sized springs, So those with greater space requirements than actually necessary.

By the comparatively increased applied axial forces to realize the translation movement during assembly with the stronger spring can also arise an increased installation costs. Since the adapted with respect to the axial force springs under certain circumstances have a comparatively large winding distance can they are in the usual storage as bulk material easily get caught in each other in their storage containers, which in the Result requires a time-consuming manual separation at the assembly site. As a result, thus the advantages of the type described above come so far only imperfectly to bear.

Object of the invention

Of the Invention is therefore based on the object as possible compactly built automatic tensioning system for a traction mechanism drive to develop and to provide a method for its assembly, which Avoid the disadvantages described above, in particular assembly technology simplified and yet inexpensive.

Summary of the invention

Of the The invention is based on the recognition that automatic belt tensioning systems, to fulfill their function torsion springs with relative high torsional moment but only low axial forces need to be advantageously equipped with these springs can, if additional measures to Guaranteed automatic assembly made which are in particular a danger of collisions arranged by Avoid path limiting means during assembly.

The invention is therefore based on an automatic tensioning system for a traction mechanism drive, for example for use on internal combustion engines of motor vehicles, comprising a clamping arm rotatably supported by a housing part on a machine part with at least one tensioning pulley for supporting on a traction means, one used in the housing part, with a Torque on the tension arm effective torsion spring to produce a continuous bias of the traction means, a damping unit for damping of Clamping arm movements, as well as a travel limit with corresponding clamping arm side and housing part-side limiting means for limiting a maximum working range of the clamping arm.

moreover is in this clamping system according to the invention provided that between the housing part and the clamping arm a spreading means designed as an assembly aid is arranged above that the clamping arm in a mounting position relative to the Housing part is axially spaced.

By This structure is advantageously achieved that in clamping systems space- and inexpensive torsion springs with comparatively low Axialkraftkomponenten can be used without thereby affecting their automatic mountability or an additional installation effort arises.

This can be particularly simple by a spring element, for example a Spring ring, can be achieved, in a mounting position clamping arm and housing part corresponding to the axial overlap of the Wegbegrenzungsmittel, the housing side an axial projection on a base plate and tension arm side two the maximum working range the clamping arm limiting radially projecting end stops having the projection in the mounting position to the work area axially spaced and engages in a working position in the work area, keeps apart.

at a particularly compact design is the damping unit formed as an annular friction element, with the Clamping arm axially displaceable over a non-rotatable connection is connectable and has a circumferentially forming friction lining, the associated with the housing part, accordingly trained contact surfaces in frictional contact can be adjusted. The damping unit is facing on the clamping arm arranged front end of the housing part.

The Torsion spring is designed as a helical spring, that of the damping unit is disposed upstream of the clamping arm facing away from the front side, wherein she with her one end of the spring in an annular Recording of the friction element and with its other spring end inside supported by the housing part, so that at a rotation of the rotatably connected to the clamping arm friction element, the torsion spring generates a restoring torque. If necessary, can the torsion spring acting as a compression spring, in addition Compensate axial bearing tolerances of the clamping system.

Of the Spring ring can be advantageously integrated into the damping unit be. In this case, the spring ring facing on the clamping arm Side fixed to the friction element on one side by means of a fastening, So for example, be selectively attached or held, where the spring washer outside the mounting in the mounting position protrudes axially to fulfill the expansion function and in the assembled state in a receptacle, for example in a Groove is sunk on the friction element.

By this arrangement, the friction element is used as a multifunction part, which produces both the friction work for damping the Schwenkarmbewegung, as well as the torsional moment of the torsion spring for generating the Belt tension transfers and over the Integrated spring ring as a so-called "lifter" or lifter acts in the mounting or lifting position. Instead of an integrated one Spring element are also separate spring elements, for example in shape a wave spring, possible. Basically come Other suitable spreading, for example, variable in length Spacers or releasable locks, into consideration.

Essential for the assembly and the function of the clamping system is included a rotationally fixed axially displaceable connection of friction element and Tensioning arm to the torsional moment of the spring also in the raised To be able to transfer the assembly position (lift position). This can be particularly easy, easy to install and secure by a shaft-hub connection in the form of a sliding spline be realized with a splined profile, wherein the spline by a formed on the tension arm wave or axis-shaped approach with an external toothing and one on the friction element trained hub with a corresponding internal toothing is formed. Possible for a proper Positive locking is also a particularly cost-effective connection with corresponding and interlocking ones D-shaped fasteners.

Furthermore, the invention is based on a method for mounting an automatic tensioning system for a traction mechanism drive, for example for use on internal combustion engines of motor vehicles, comprising a clamping arm rotatably supported by a housing part on a machine part with at least one tensioning pulley for supporting on a traction means, one in the housing part with a torque acting on the tensioning arm torsion spring for generating a continuous bias of the traction means, a damping unit for damping Spannarmbewegungen, and a travel limit with corresponding clamping arm side and housing part-side limiting means for limiting a maximum working range of the clamping arm. In addition, according to the method is provided that during assembly of the clamping arm relative to the housing part by means of a between the Housing part and the clamping arm arranged as an assembly aid spreading is axially spaced in a mounting position.

Thereby will ensure that the means to limit travel Housing part and clamping arm when manufacturing the clamping system do not bother. The torsion spring of the clamping system is doing from the spreading function to overcome an overlap of interlocking path limiting means during assembly freed. Thus, this property does not need in the selection of the torsion spring to be considered, which is space and cost and mounting technology advantageous.

• a) Zusammensetzen der Baugruppe, im Wesentlichen umfassend die Dämpfungseinheit mit dem Spreizmittel, die Torsionsfeder, das Gehäuseteil sowie den Spannarm, wobei der Spannarm verdrehgesichert wird,
• b) Ausrichten und Stabilisieren der Baugruppe, wobei die Torsionsfeder sich mit einem Federende an dem Gehäuseteil und mit dem anderen Federende an der Dämpfungseinheit abstützt und die Dämpfungseinheit axial verschiebbar drehfest mit dem Spannarm verbunden wird,
• c) Verdrehen des Gehäuseteils unter Mitnahme des gehäuseteilseitigen Federendes in der Montageposition, bis eine vorgegebene Vorspannung der Torsionsfeder erreicht ist, wobei die korrespondierenden Begrenzungsmittel der Wegbegrenzung in eine Verriegelungsstellung zueinander ausgerichtet werden,
• d) Verschieben des Gehäuseteils mit Torsionsfeder und Dämpfungseinheit in Richtung zum Spannarm bis zu einen axialen Endanschlag, wobei das Spreizmittel komprimiert wird und die Wegbegrenzungsmittel ineinander greifen, und
• e) Sicherung des Spannarms mittels einer Axialsicherung in einer Endposition, beispielsweise durch Verstemmen benachbarter Fügeteile.

In a particularly advantageous embodiment of the method, an assembly sequence can be provided with the following steps:

• a) assembling the assembly, essentially comprising the damping unit with the spreading means, the torsion spring, the housing part and the clamping arm, wherein the clamping arm is secured against rotation,
• b) aligning and stabilizing the assembly, wherein the torsion spring is supported with a spring end on the housing part and with the other spring end of the damping unit and the damping unit is axially displaceable rotatably connected to the clamping arm,
• c) rotation of the housing part with entrainment of the housing-side spring end in the mounting position until a predetermined bias of the torsion spring is achieved, wherein the corresponding limiting means of Wegbegrenzung are aligned in a locking position to each other,
• d) moving the housing part with torsion spring and damping unit in the direction of the clamping arm up to an axial end stop, wherein the spreading means is compressed and the Wegbegrenzungsmittel interlock, and
• e) securing the clamping arm by means of an axial securing in an end position, for example by caulking adjacent joining parts.

By this assembly sequence can, in operative connection with the spreading, an automatic assembly, in particular the assembly steps c) Twist (rotation) and d) Translation, one such clamping system by means of an automatic mounting device be guaranteed.

Brief description of the drawings

The The invention will be described below with reference to the accompanying drawings some embodiments explained in more detail. It shows

1 a perspective view of an automatic clamping system,

2 a perspective view of a clamping arm with a spline for connection to a friction element,

3a the friction element with an integrated spring element as a spreading means, in a perspective view obliquely from below,

3b the friction element according to 3a in a further perspective view obliquely from above,

4 a clamping system in longitudinal section in a mounting position, and

5 the completely assembled clamping system in longitudinal section.

Detailed description the drawings

The 1 shows an automatic clamping system of a belt drive for driving ancillaries on an internal combustion engine of a motor vehicle. The operation of such a mechanical belt tensioner is known per se. The description is therefore limited to the components essential to the invention and a method according to the invention for Mon days of such a clamping system and its preparation for Einssatz on a belt drive.

The clamping system has a clamping arm 1 on, a rotatably mounted tensioner 2 for resilient support on a (not shown) belt carries. The tension arm 1 is frontally on a housing part 3 (in 1 is for simplicity only a base plate 4 shown) rotatably mounted. The housing part 3 respectively. 4 is fixed to a machine part, not shown, for example, a crankcase of the internal combustion engine, fastened. The base plate 4 has at its front side the clamping arm 1 facing the end an axial projection 5 up in a window 6 engages, the circumference or angle angle related to a working area of the clamping arm 1 within which it is pivotable defined. The workspace 6 is by two radially projecting end stops 7 . 8th of the tensioning arm 1 limited. The lead 5 and the end stops 7 . 8th form a path limitation in operative connection 23 of the clamping system. Furthermore, are radially inside the base plate 4 a torsion spring 9 and a damping unit 10 indicated.

The in 2 shown clamping arm 1 has a hollow shaft 11 with an outer multi-tooth profile 12 on that together with a hub 13 the damping unit 10 ( 3a and 3b ), at which an ent talking inside variety profile 14 is formed, advantageously designed as a spline form-fitting rotationally fixed shaft-hub connection 15 ( 4 ) between the tensioning arm 1 and the damping unit 10 form.

In the 3a and 3b shown damping unit 10 is advantageous as an annular friction element with a circumferential, at an opening gap 18 interrupted, friction lining 16 educated. The friction lining 16 , is at a fortification 17 held, with the opening gap 18 the attachment 17 opposite. The attachment 17 is formed as a ring segment-like web, which is the hub 13 and the friction lining 16 spaced connects.

On the tension arm 1 facing end face of the friction element 10 the bridge closes 17 a trained as an open spring ring axial expansion 19 one. The spring ring 19 gets through the jetty 17 held unilaterally, so that its opening or interruption 22 the jetty 17 It is circumferentially opposite and it is outside the fixture 17 protrudes frontally, thereby providing an axially directed spring force.

4 shows the clamping system in a mounting position, wherein the friction element 10 and the torsion spring 9 in the housing part 3 are used. The friction element 10 is at the tension arm 1 facing front end of the housing part 3 arranged and with the hub 13 positive locking against rotation on the shaft 11 of the tensioning arm 1 attached. The open annular friction lining 16 is with radial bias in the housing part 3 used, so that the opening gap 18 within the housing part 3 closes and the friction lining 16 with unspecified explained, the housing part 3 associated contact surfaces is in frictional contact.

The thighless torsion spring 9 supports with a spring end within the housing part 3 and with her other spring end on the tension arm 1 facing away from the front side of the friction element 10 within the friction element 10 off so that on the friction element 10 a radial force and a relative rotation between clamping arm 1 and housing part 3 a torsional moment of the torsion spring 9 is produced. The tension arm 1 is also by means of a sliding bearing 25 in the housing part 3 rotatably mounted. This is the hollow shaft 11 on a coaxial with the hollow shaft 11 on the housing part 3 trained, frontally in the direction of the clamping arm 1 protruding wave 24 placed.

The spring ring 19 is supported by a contact surface 20 of the tensioning arm 1 spring-loaded and ensured - as long as it is not compressed axially - an axial distance from the clamping arm 1 and housing part 3 , It defines the axial length and the axial angle of the spring ring 19 the axial distance between the housing part 3 and tension arm 1 firmly in the mounting position. The axia le length and the axial angle of the spring ring 19 are chosen so that in the mounting position (lift position) of the projection 5 the path limitation 23 ( 1 ) axially not with the end stops 7 . 8th of the work window 6 overlaps.

The 5 finally shows the clamping system in fully assembled state. Here is the spline 15 ( 4 ) pushed so far that the front end of the housing part 3 or the shaft 24 at an axial end stop 21 of the tensioning arm 1 is applied and, for example, axially secured by caulking unspecified explained adjacent joining parts. Here is the spring washer 19 compressed after fulfillment of its assembly function and flat in the friction element 10 sunk.

For simplicity, in 4 and 5 has been dispensed with the representation of a tensioner. In addition, it is irrelevant for the invention, whether the tension roller 2 on the tension arm 1 on the housing side, as in 1 , or on the housing part 3 opposite side, as in 2 , is arranged. Also clamping arms with two levers for attaching two oppositely effective tension rollers are possible.

To mount such a clamping system using an automatic mounting device, the housing and Spanarmbauteile are first placed step by step and then centered and stabilized in one operation, wherein the clamping arm 1 and with this the tension arm 1 non-rotatably connected friction element 10 , For example by means of an external tool, which in a positive reception of the clamping arm 1 is used, is secured against rotation.

After that, the base plate 4 or the housing part 3 taking along the housing-side spring end of the torsion spring 9 twisted until the projection 5 of the housing part 3 into the work window 6 can engage, causing the torsion spring 9 or the clamping arm 1 is biased. This is the base plate 4 opposite the clamping arm 1 by means of the spreading agent 19 so far raised axially that projection 5 and end stops 7 . 8th the path limitation 23 are sufficiently axially spaced so that they can not collide with each other during rotation.

If the lead 5 the working window 6 is opposite, then the base plate 4 or the housing part 3 with the friction element 10 and the torsion spring 9 axially in the direction of the clamping arm 1 up to the axial end stop 21 postponed, where the spline 15 further pushes each other and the spreading is compressed axially.

Finally the assembly is secured axially by caulking. The Clamping system is then - after removing the anti-rotation - to Use on traction drive ready.

1

clamping arm

2

idler

3

housing part

4

baseplate

5

head Start

6

Workspace

7

end stop

8th

end stop

9

torsion spring

10

damping unit

11

wave

12

Multi-tooth profile

13

hub

14

Multi-tooth profile

15

Connection, splines

16

friction lining

17

attachment

18

opening

19

spreading

20

contact surface

21

end stop

22

opening

23

travel limitation

24

wave

25

bearings

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4220879 A1 [0007]
• EP 0780597 B1 [0007]
• - DE 4300178 C1 [0007]
• - DE 60105759 T2 [0007]
• - DE 10055594 A1 [0008]
• - DE 10328900 A1 [0009]
• DE 10152364 A1 [0010]
• DE 102004028485 A1 [0010]

Claims (21)

Automatic tensioning system for a traction mechanism drive, for example for use on internal combustion engines of motor vehicles, comprising a housing part ( 3 ) on a machine part rotatably storable clamping arm ( 1 ) with at least one tensioning roller ( 2 ) for supporting on a traction means, one in the housing part ( 3 ), with a torque on the clamping arm ( 1 ) effective torsion spring ( 9 ) for generating a continuous bias of the traction means, a damping unit ( 10 ) for damping tension arm movements, as well as a travel limit ( 23 ) with corresponding clamping arm-side and housing-part limiting means ( 5 . 7 . 8th ) to limit a maximum workspace ( 6 ) of the tensioning arm ( 1 ), characterized in that between the housing part ( 3 ) and the tensioning arm ( 1 ) designed as a mounting aid spreading ( 19 ) is arranged, over that the tensioning arm ( 1 ) in a mounting position relative to the housing part ( 3 ) is axially spaced. Tensioning system according to claim 1, characterized in that the spreading means ( 19 ) is formed as a spring element. Clamping system according to claim 1 or 2, characterized in that the spreading means ( 19 ) in the damping unit ( 10 ) is integrated. Clamping system according to claim 1 or 2, characterized in that the spreading means ( 19 ) is formed as a separately arranged spring element. Clamping system according to at least one of the claims 1 to 4, characterized in that the spring element as a spring ring, a spring washer or a corrugated spring is formed. Clamping system according to at least one of claims 1 to 5, characterized in that the damping unit ( 10 ) is formed as an annular friction element, which with the clamping arm ( 1 ) via a non-rotatable connection ( 15 ) is axially slidably connectable, and that the damping unit ( 10 ) a friction lining forming the circumference ( 16 ), which is connected to the housing part ( 3 ) associated, correspondingly trained contact surfaces in frictional contact can be adjusted. Clamping system according to at least one of claims 1 to 6, characterized in that the spring element ( 19 ) as one in the friction element ( 10 ) integrated spring ring is formed. Clamping system according to claim 7, characterized in that the spring ring ( 19 ) on the tensioning arm ( 1 ) facing side on the friction element ( 10 ) by means of a fastening ( 17 ) is fixed on one side, wherein the spring ring ( 19 ) outside the attachment ( 17 ) protrudes in the mounting position to fulfill the expansion function frontally and in the assembled state in a receptacle on the friction element ( 10 ) is sunk. Clamping system according to at least one of claims 1 to 8, characterized in that the rotationally fixed connection ( 15 ) between the friction element ( 10 ) and the tensioning arm ( 1 ) is formed as a positive shaft-hub connection. Clamping system according to at least one of claims 1 to 9, characterized in that the rotationally fixed connection ( 15 ) between the friction element ( 10 ) and the tensioning arm ( 1 ) is designed as a spline. Clamping system according to claim 10, characterized in that the spline ( 15 ) by one on the clamping arm ( 1 ) formed wavy approach ( 11 ) with an external toothing ( 12 ) and one on the friction element ( 10 ) trained hub ( 13 ) with a corresponding internal toothing ( 14 ) is formed. Clamping system according to at least one of claims 1 to 9, characterized in that a rotationally fixed connection between the friction element ( 10 ) and the tensioning arm ( 1 ) is designed as a rotational lock. Clamping system according to claim 12, characterized in that the rotational locking by a on the clamping arm ( 1 ) formed D-shaped shaft projection and one on the friction element ( 10 ) formed hub with a corresponding D-shaped recess is formed. Clamping system according to at least one of claims 1 to 13, characterized in that the damping unit ( 10 ) on which the tensioning arm ( 1 ) facing the front end of the housing part ( 3 ) is arranged, and that the torsion spring ( 9 ) of the damping unit ( 10 ) on the tensioning arm ( 1 ) facing away from the end of the damping unit ( 10 ) is upstream. Clamping system according to at least one of claims 1 to 14, characterized in that the torsion spring ( 9 ) is designed as a helical spring which, with its one spring end in a ringförmi gene recording of the friction element ( 10 ) and with its other spring end within the housing part ( 3 ) is supported, so that in a rotation of the with the clamping arm ( 1 ) rotatably connected friction element ( 10 ) the torsion spring ( 9 ) generates a restoring torque. Clamping system according to claim 15, characterized in that the helical spring ( 9 ), an axial bearing tolerances compensating, axial force component has. Clamping system according to at least one of claims 1 to 16, characterized in that the travel limit ( 23 ) on the housing side an axial projection ( 5 ) on a base plate ( 4 ) and tension arm side two the maximum working area ( 6 ) of the tensioning arm ( 1 ) limiting radially projecting end stops ( 7 . 8th ), wherein the projection ( 5 ) in the mounting position to the work area ( 6 ) is axially spaced and in a working position in the work area ( 6 ) intervenes. Clamping system according to at least one of claims 1 to 17, characterized in that means for mutual axial securing of clamping arm ( 1 ) and housing part ( 3 ) are provided in the assembled state. Method for mounting an automatic tensioning system for a traction mechanism drive, for example for use on internal combustion engines of motor vehicles, comprising a housing part ( 3 ) on a machine part rotatably storable clamping arm ( 1 ) with at least one tensioning roller ( 2 ) for supporting on a traction means, one in the housing part ( 3 ) with a torque on the clamping arm ( 1 ) effective torsion spring ( 9 ) for generating a continuous bias of the traction means, a damping unit ( 10 ) for damping tension arm movements, as well as a travel limit ( 23 ) with corresponding clamping arm-side and housing-part limiting means ( 5 . 7 . 8th ) to limit a maximum workspace ( 6 ) of the tensioning arm, characterized in that during assembly of the tensioning system the tensioning arm ( 1 ) relative to the housing part ( 3 ) by means of a between the housing part ( 3 ) and the tensioning arm ( 1 ) arranged as an assembly aid spreading ( 19 ) is axially spaced in a mounting position. A method according to claim 19, characterized in that during assembly of the clamping system, an assembly sequence is carried out with the following steps: a) assembly of the assembly, essentially comprising the damping unit ( 10 ) with the spreading agent ( 19 ), the torsion spring ( 9 ), the housing part ( 3 ) and the tensioning arm ( 1 ), whereby the tensioning arm ( 1 ) is secured against rotation, b) aligning and stabilizing the assembly, wherein the torsion spring ( 9 ) with a spring end on the housing part ( 3 ) and with the other spring end on the damping unit ( 10 ) and the damping unit ( 10 ) axially displaceable rotationally fixed with the clamping arm ( 1 ), c) twisting the housing part ( 3 ) with entrainment of the housing-side spring end in the mounting position until a predetermined bias of the torsion spring ( 9 ), the corresponding limiting means ( 5 . 7 . 8th ) of the path limitation ( 23 ) are aligned in a locking position to each other, d) displacement of the housing part with torsion spring ( 9 ) and damping unit ( 10 ) in the direction of the tensioning arm ( 1 ) up to an axial end stop ( 21 ), wherein the spreading agent ( 19 ) is compressed and the Wegbegrenzungsmittel ( 5 . 7 . 8th ) and e) securing the clamping arm ( 1 ) by means of an axial securing in an end position. Method according to claim 20, characterized in that that at least the assembly steps twisting (c) and moving (D) carried out by means of an automatic mounting device become.