DE102006054963A1 - Clamping device of a traction mechanism drive - Google Patents

Abstract

The invention relates to a tensioning device of a traction mechanism drive, comprising a tensioning lever (2) mounted rotatably on a base housing (4) and radially spaced from the axis of rotation (5) of the sc). The tension lever (2) is secured by a helical spring (15 ) formed coaxially with the pivot bearing (3), and at the spring ends (16, 17) housing side with the base housing (4) and lever side with the clamping lever (2) operatively connected torsion spring (14) rehachse (5) of the pivot bearing ( 3) can be acted upon, wherein the pivot bearing (3) by a bearing pin (8), a bearing hub (9) and at least one between the bearing pin (8) and the bearing hub (9) arranged plain bearing bush (10) is formed, and wherein a middle Radial force application plane of the tension roller to a central radial bearing plane of the pivot bearing (3) is axially spaced. To improve the balance of the pivot bearing and the adjustability of the friction damping of the clamping lever is the lever-side spring end (16) of the torsion spring (14) via a wedge element (20) and a lever-fixed driver (21) with the clamping lever (2) in connection, wherein the wedge element (20) with an axially-radially aligned pressure surface (22) on the lever-side spring end (16) of the coil spring (15) is present, and with a radially outward of the lever-side spring end (16) away ...

Description

Field of the invention

The Invention relates to a tensioning device of a traction mechanism drive, with one over a pivot bearing rotatably mounted on a base housing and radially spaced from the pivot axis of the pivot bearing with a rotatable tensioner pulley provided tension lever, by means of a thighless coil spring trained, arranged coaxially to the pivot bearing and to the Spring ends on the housing side with the base housing and on the lever side in operative connection with the clamping lever Torsion spring with a torsional moment about the axis of rotation of the pivot bearing can be acted upon, wherein the pivot bearing by a bearing pin, a bearing hub and at least one between the bearing pin and the bearing hub arranged plain bearing bush is formed, and wherein a mean radial force application plane of the tension roller to a middle Radial bearing plane of the pivot bearing is axially spaced.

Background of the invention

jigs with a plain bearing designed as a plain bearing, one as a coil spring trained torsion spring and an axially beab stood arrangement The tensioner and the pivot bearing come in different embodiments preferred for accessory trains of internal combustion engines for use. Such tensioning devices are both in an internally mounted design with a storage of rigidly connected to the clamping lever bearing pin in the one component of the base housing forming bearing hub as well as in an externally mounted design with a bearing rigidly connected to the clamping lever bearing hub on the one part of the base housing forming bearing pin known. Here is the base housing in each case for fastening the respective clamping device to a Motor housing, such as. the crankcase or the control housing a combustion piston engine provided.

Regarding the arrangement of the tension roller can in such a clamping device additionally between a so-called offset or Z design, in which the tension roller axially on the of the base housing opposite outside of the clamping lever is arranged, and a so-called inline design or U-execution, in which the tension roller radially on the side of the base housing axially the base housing facing the inside of the clamping lever is arranged, distinguished become.

The Swivel bearing, through which the radial bearing of the clamping lever in or on the base housing is accomplished, has at least one plain bearing bush, which is arranged between the bearing hub and the bearing pin and mostly of a resistant and at the same time low-friction plastic material. The plain bearing bush and the inner bearing wall of the bearing hub in contact therewith and outer storage wall of the bearing pin can formed in a known manner cylindrical or conical cylindrical be, wherein in a cylindrical pivot bearing an additional Thrust bearing, e.g. in the form of a between a housing fixed and a lever-mounted bearing plate arranged plain bearing disc is required, whereas a conical-cylindrical pivot bearing in conjunction with an axial bias of the torsion spring thrust bearing of the clamping lever includes.

Independent of the geometric structure of the pivot bearing acts on the at least a plain bearing bush is a resultant radial force resulting from the force acting on the clamping lever spring force of the torsion spring and that of the traction means over the tension pulley exerts on the tension lever exerted reaction force. But there at least one of the radial planes in which the spring force the torsion spring and the reaction force of the traction means on the clamping lever acting, usually axially spaced from a central radial Bearing level of the pivot bearing and the plain bearing bush of the pivot bearing is, inevitably results a resulting tilting moment about a tilt axis perpendicular to the Rotary axis of the pivot bearing is located in the middle storage level.

This Tilting momentarily causes an uneven, so axially end diagonally opposite effective, one-sided load of the pivot bearing with a high local pressure and edge load of the plain bearing bush to uneven wear of the plain bearing bush and therefore undesirable Misalignment of the clamping lever and attached to this tensioner in terms of of the traction device leads.

In order to achieve the most complete possible balancing of the pivot bearing and thus a tilting moment-free and thus uniform loading of the plain bearing bush and at the same time an effective friction damping pivotal movement of the clamping lever and thus a vibration of the tensioning roller running on the tension roller is in the not previously published patent application DE 102 006 014 942.4 the Applicant has already proposed a novel tensioning device, in which the torsion spring is designed as a legless helical spring capable of loading in the opening direction. The lever-side spring end of the torsion spring is located on an axially-radially aligned Anschlagflä che of a lever-proof driver. The driver is with respect to the rotational axis of the pivot bearing circumferentially arranged such that the stop surface is aligned normal to a resultant reaction force of a traction means on the tension roller. The support of a reaction force of the clamping lever on the coil spring takes place relative to the base housing. The middle of the lever-side spring end is axially spaced apart from the central bearing plane of the pivot bearing, so that the tilting moments of the tangential spring force of the coil spring and the effective over the tensioning roller on the clamping lever resulting reaction force of the traction device largely cancel each other out.

The support the reaction force of the clamping lever takes place on the coil spring preferably over a shoe, which is about the axis of rotation of the pivot bearing on the outer lever-side turn the coil spring from the stop surface of the driver to about Rearranged 90 ° is radially inward on the outer lever side Winding the coil spring is applied, in a radial guidance of the Clamping levers guided radially movable is, and radially outside with a friction surface a cylindrical inner wall of the base housing rests. This results a high spring force proportional and thus of the current Position of the clamping lever dependent friction damping the pivoting movement of the clamping lever.

One additional friction torque for damping a pivoting movement of the clamping lever and a further leverage for balancing the pivot bearing can by a corresponding Arrangement of a second shoe on the outer housing side turn of the coil spring be achieved. The local reaction force of the base housing on the Coil spring is both as a radial contact force of the shoe against a cylindrical inner wall of the clamping lever as well as balancing leverage around the tilt axis of the plain bearing bush of the pivot bearing effectively.

Despite the benefits of the DE 102 006 014 942.4 known clamping device may in certain applications, the existing options may not be sufficient or, for example due to cramped space at the installation, not used or optimally utilized to achieve a complete balance of the pivot bearing and / or setting a desired damping behavior of the jig.

Object of the invention

It is therefore the object of the present invention, from the DE 102 006 014 942.4 known tensioning device in terms of alternative and / or complementary opportunities for balancing the pivot bearing and to adjust the friction damping of the clamping lever.

Summary of the invention

The invention is based on the finding that a friction torque for friction damping of a pivoting movement of the tensioning lever can also be generated by a support of the lever-side tangential spring force F _{F_T of} the torsion spring with respect to the lever-fixed driver via a wedge element. In this case, a radial contact force F _{K_R is} generated by a support of the wedge element on the driver on both sides wedge surfaces, pressed with the wedge element radially outward with an outer cylindrical friction surface against a cylindrical inner wall of the base housing and thus during a pivoting movement of the clamping lever due to the tangential relative movement between the Wedge element and the base housing a friction torque is generated.

The invention therefore relates to a tensioning device of a traction mechanism drive, with a rotatably mounted on a base housing via a pivot bearing and radially spaced from the axis of rotation of the pivot bearing provided with a rotatable tension roller clamping lever, which is arranged by means of a thighless helical spring, coaxial with the pivot bearing and to the Spring ends on the housing side with the base housing and lever side operatively connected to the tensioning lever torsion spring with a torsional moment M _T is acted upon about the axis of rotation of the pivot bearing, wherein the pivot bearing is formed by a bearing pin, a bearing hub and at least one arranged between the bearing pin and the bearing hub plain bearing bush, and wherein a central radial force application plane of the tension roller is axially spaced from a central radial bearing plane of the pivot bearing. According to the invention, it is additionally provided that the lever-side spring end of the torsion spring is connected to the tension lever via a wedge element and a lever-fixed catch, wherein the wedge element rests against the lever-side spring end of the coil spring with an axially-radially aligned pressure surface, with a radially outward distance from the latter Lever-side spring end away inclined wedge surface rests against an equally inclined wedge surface of the driver, and rests with an outer cylindrical friction surface on a cylindrical inner wall of the base housing.

Due to the wedge element, the lever-side tangential spring force F _{F_T of} the torsion spring whose height increases or decreases in proportion to the current torsional moment between the tensioning lever and the base housing, depending on the inclination of Wedge surfaces of the wedge element and the driver according to the vectorial balance of forces on the wedge element in a normal standing on the wedge surface of the wedge element support force F _{K_N} and converted into a radial contact force F _{K_R} . While the support force F _{K_N is introduced} via the wedge surface of the driver in the clamping lever and is used to balance the at least one plain bearing bushing of the pivot bearing, the wedge member is pressed by the radial contact force F _{K_R} with its outer cylindrical friction surface against the cylindrical inner wall of the base housing, whereby a Friction torque for friction damping of a pivoting movement of the clamping lever is generated about the axis of rotation of the pivot bearing.

The angle of inclination of the two wedge surfaces serves as an adjustment parameter for adjusting the height and direction of the support force F _{K_N} and the height of the radial contact force F _{K_R} . Due to the wedge element also results in the positive side effect that by the tangential friction force F _{R_T} between the wedge member and the clamping lever, the radial contact force F _{K_R} and thus the effective friction torque at a compression of the clamping lever with respect to the torsion spring, a swinging of the tensioning roller of the traction means corresponds to, additionally increased and at a rebound of the clamping lever with respect to the torsion spring, which corresponds to a pivoting of the tensioning roller to the traction means out, is additionally reduced.

This Effect is quite desirable as an outward swing the traction means characterized due to the increased friction damping of the Clamping lever in addition is inhibited, and inward swinging the tension means the tension roller due to the reduced friction damping of the clamping lever largely delay-free tracked becomes. With the use of the wedge element is thus a simple as well as space-saving option a further adjustment of the balance of the pivot bearing and an additional or alternative friction damping of the clamping lever available.

advantageous Embodiments and developments of the clamping device according to the invention are in the claims 2 to 20 indicated.

The driver is preferably arranged circumferentially with respect to the axis of rotation of the pivot bearing such that the wedge surfaces of the wedge element and the driver are aligned largely normal, ie perpendicular, to a resultant reaction force F _{Z_R of} a traction device on the tension roller, since this directly compensates for the overturning moment of the reaction force F _{Z_R of} the pulling means on the tensioning roller about the tilting axis of the pivot bearing by the tilting moment of the supporting force F _{K_N} on the driver and thus a uniform load on the plain bearing _{bushing of} the pivot bearing is possible.

The angle of inclination of the wedge surfaces of the wedge element and the driver with respect to the pressure surface of the wedge element, via which the height and direction of the used for balancing the pivot bearing support force F _{K_N} and the amount of radial contact force F _{K_R} and thus used for the friction _{damping of} the clamping lever friction torque relative to the tangential spring force F _{F_T of} the torsion spring is adjustable, suitably lies in a range between 30 ° and 60 °.

To achieve a desired, determined by the height of the radial contact force F _{K_N of} the wedge element on the cylindrical inner wall of the base housing and the coefficient of friction between the outer cylindrical friction surface of the wedge element and the cylindrical inner wall of the base housing damping behavior, the friction surface of the wedge element and / or the cylindrical Be provided inside wall of the base housing with a friction lining. However, it is also possible that the entire wedge element consists of a resistant and friction-resistant plastic, which is in frictional contact directly with its outer cylindrical friction surface with the provided with or without friction lining cylindrical inner wall of the base housing.

to Reduce the number of components and simplify assembly the tensioning device is the wedge element expediently integral with an open bearing ring connected between the outer lever side Winding the coil spring and the clamping lever is arranged, the spaced from the wedge element against the clamping lever against form fit against a twisting is secured, and the immediately adjacent to the wedge surface of the Wedge element completely open is. In this embodiment is through the opening removed the bearing ring and its positive attachment from the wedge element sufficient mobility of the wedge element guaranteed in the circumferential direction as well as in the radial direction.

Around In this case, to achieve a space-saving design, the wedge element Advantageously protrude at least partially axially outside of the bearing ring and in a provided with the lever-side wedge surface radial groove of the Engage clamping lever.

The Radialnut of the clamping lever can circumferentially with both sides a wedge surface be provided, as this is an identical clamping lever both for a clamping device with clockwise rotating lever as well as for a clamping device with counterclockwise cocking lever is used.

In a particularly advantageous embodiment the tensioning device according to the invention, the wedge member and the driver are integrally connected to a slotted bearing ring which is disposed between the outer lever-side winding of the coil spring and the clamping lever, which is secured near the driver against the clamping lever form-fitting against rotation and against radial displacement, and between the wedge surface of the wedge element and the wedge surface of the driver is provided with a separating slot. As a result, the application-specific design features, such as the circumferential orientation and the angle of inclination of the wedge surfaces of the wedge element and the driver, combined in the bearing ring, wherein the positive fixation of the bearing ring on the clamping lever, the functional fixation of the driver and the separating slot, the relative mobility of the wedge member is ensured opposite the wedge surface of the driver.

The positive Connection of the bearing ring with the clamping lever can be appropriate by each an axial bore and a bolt inserted into the axial bores be formed. The adaptation of the peripheral position and the Direction of rotation of the clamping lever to the respective application can in a simple way by the positioning of the lever-side axial bore done in a standardized clamping lever.

Alternatively, the positive connection of the bearing ring with the clamping lever can also be formed by an axially aligned inner radial groove of the bearing ring and engaging in this, axially extending outer radial web of the clamping lever, since a load of the driver by the supporting force F _{K_N} on the relevant wedge surface only occurs in the circumferential direction and radially inward. Due to the positioning of the radial web, however, the clamping lever in this case represents an application-specific component.

Analogous to the lever-side spring end of the torsion spring, the housing-side spring end of the torsion spring can also be connected to the base housing via a wedge element and a housing-mounted driver, wherein the wedge element bears against the housing-side spring end of the helical spring with an axially-radially aligned pressure surface, with one radially outside of the housing side spring end inclined wedge surface rests against an equally inclined wedge surface of the driver, and rests with an outer cylindrical friction surface on a cylindrical inner wall of the clamping lever. Since in this case the radial contact force F _{K_R of} the wedge element is effective on the clamping lever, on the housing side by the radial contact force F _{K_R} not only a frictional torque about the axis of rotation of the pivot bearing but also a usable for balancing the pivot bearing tilting moment about one in the middle bearing plane of the Slide bearing lying tilting axis generated.

In order to achieve in connection with the lever-side radial contact force F _{K_R of} the wedge element on the clamping lever a residual torque-free compensation of the tilting moment of the reaction force F _{Z_R of} the traction means on the tensioning roller about the tilting axis of the pivot bearing and thus a uniform load of the plain bearing bushing of the pivot bearing, the housing-fixed driver expedient with respect to the axis of rotation of the pivot bearing circumferentially arranged such that an imaginary, the radial contact force F _{K_R} of Keilelemen tes containing radial surface is aligned substantially parallel to the resulting reaction force F _{Z_R of} the traction means on the tension roller.

The another, previously for the lever-side spring end of the torsion spring or the lever-side area the clamping device specified design features are under consideration a construction-related permutation of clamping lever and base housing as well on the housing side Spring end of the torsion spring or the housing-side region of the clamping device applicable.

As in principle already from the DE 102 006 014 942.4 is known, the lever-side support of the reaction force F _{F_R of} the clamping lever on the coil spring to generate a further friction torque via a sliding shoe, which is arranged offset back about the axis of rotation of the pivot bearing of the lever-side spring end by about 90 °, radially inward on the outer lever-side winding of the coil spring rests, is guided radially movable in a radial guide of the clamping lever, and rests with an outer cylindrical friction surface on a cylindrical inner wall of the base housing.

In this case, an increasingly rotationally dependent friction torque can be achieved, that the sliding shoe and the radial guide circumferentially on the side facing the lever side spring end each have a radially outwardly inclined to the lever side spring end wedge surface. Due to the wedge surfaces, the sliding _shoe is additionally pressed radially outwardly with a compression of the tensioning lever with respect to the torsion spring and thus the friction torque generated by the reaction force F _{F_R} is increased.

Likewise, the housing-side support of the reaction force F _{F_R of} the base housing can take place on the helical spring via a sliding shoe, which is arranged offset back about 90 ° about the axis of rotation of the pivot bearing of the housing-side spring end, radially inward on the outer housing side winding of the coil spring rests, is guided radially movable in a radial guide of the base housing, and rests with an outer cylindrical friction surface on a cylindrical inner wall of the clamping lever, wherein the sliding shoe and the radial guide circumferentially on the housing side spring end side facing one radially outward to the have housing-side spring end inclined wedge surface.

at two Gleitschuhanordnungen is the inclination angle of the wedge surfaces of the Sliding shoe and the radial guide across from an imaginary, the axis of rotation of the pivot bearing and containing the outside cylindrical friction surface of the shoe in approximately halving radial plane, over the the direction of rotation dependent reinforcement the friction torque is adjustable, each preferably in a range between 30 ° and 60 °.

at sufficient flexibility of the respective bearing ring, the shoe can be integral with be associated with the respective bearing ring, whereby the number of components reduces and the assembly of the clamping device is facilitated.

In case of a housing-side use of a wedge element and a sliding shoe, which are both pressed against a cylindrical inner wall of the clamping lever, the resultant force vector from the radial contact force F _{K_R of} the wedge element and effective as a radial contact force of the sliding shoe reaction force F should for the fullest possible balancing of the pivot bearing _{F_R be aligned} largely parallel to the resulting reaction force F _{Z_R of} the traction device on the tension roller.

As an alternative to the use of a sliding _shoe, the lever-side support of the reaction force F _{F_R of} the tensioning lever on the helical spring can also be achieved via direct contact of a portion of the outer lever-side turn of the helical spring with a cylindrical portion lying about 90 ° past the axis of rotation of the pivot bearing from the lever-side spring end Inner wall of the base housing, wherein at least the outer lever-side turn of the coil spring and / or the cylindrical inner wall of the base housing is provided with a friction coating.

In the same way, the housing-side support of the reaction force F _{F_R of} the base housing on the coil spring via an immediate contact of a about the axis of rotation of the pivot bearing of the housing side spring end of about 90 ° back portion of the outer housing side winding of the coil spring with a cylindrical inner wall of the Clamping levers take place, wherein also at least the outer housing-side winding of the coil spring and / or the cylindrical inner wall of the clamping lever is provided with a friction coating.

at a direct frictional contact of the outer turn of the coil spring with the base housing and / or the tensioning lever can advantageously complete with the coil spring be provided a friction coating. This friction coating works at the same time as corrosion protection, leaving an otherwise required Corrosion protection treatment of the coil spring can be omitted.

In conclusion, be It should be noted that the above-described embodiments, such as the use of a lever-side wedge element, a housing-side Wedge element, a lever-side sliding shoe with a wedge surface, one the housing side Sliding shoe with a wedge surface and a direct lever side and / or housing side frictional contact of the Coil spring with the base housing or with the clamping lever can be combined with each other and at least partially applicable to other types of clamping devices are.

Brief description of the drawings

The Invention will now be described with reference to the accompanying drawings some embodiments explained in more detail. In this shows

1 a preferred embodiment of the clamping device according to the invention in a perspective exploded view,

2 an enlarged section of 1 .

3 an axial view of a bearing ring of the clamping device according to 1 and 2 with axially outward looking direction,

4a at a wedge element of the clamping device according to the 1 to 3 attacking forces in a schematic representation,

4b the static equilibrium of forces on the wedge element 4a in a vector representation,

4c the dynamic balance of forces on the wedge after 4a in a torsion spring exciting pivotal movement of the clamping lever in a vector representation,

4d the dynamic balance of forces on the wedge after 4a when the torsion spring relaxing pivotal movement of the clamping lever in a vector representation,

5 an alternative embodiment of a clamping device according to the invention in a partially sectioned axial view,

6a a bearing ring of a further embodiment of the clamping device according to the invention in a schematic axial view,

6b a tensioning lever of the further variant of the tensioning device according to the invention 6a in a schematic axial view,

7 a first embodiment of a spring force support of the torsion spring of the tensioning device in a schematic axial view, and

8th a second embodiment of a spring force support of the torsion spring of the tensioning device in a schematic sectional view.

Detailed description the drawings

Since the basic structure and operation of the generic, provided with a thighless coil spring tensioning device already in the DE 102 006 014 942.4 has been described and explained in detail, the following description is limited to the novel features of the present invention.

A preferred embodiment of the tensioning device according to the invention 1 a traction drive is in 1 shown in a perspective exploded view. In a so-called offset or Z arrangement is a tension lever 2 over a pivot bearing 3 rotatable on a pot-shaped base housing 4 stored. Radially spaced from the axis of rotation 5 of the pivot bearing 3 is the cocking lever 2 with a not shown here, about an axis-parallel axis of rotation 6 provided rotatable tension pulley over which the traction means of a traction mechanism drive is guided in the installed state.

The pivot bearing 3 is presently cylindrical and is made of a via a serration 7 rigid with the base housing 4 connected bearing pin 8th , one rigid with the tension lever 2 connected bearing hub 9 and one between the bearing pin 8th and the warehouse hub 9 arranged plain bearing bush 10 educated. For axial bearing of the clamping lever 2 is a plain bearing disc 11 provided, which integral with the plain bearing bush 10 is connected and between a lever-proof bearing plate 12 and one rigid with the bearing pin 8th connected storage plate 13 is arranged. The tension lever 2 and the base housing 4 stand over a torsion spring 14 positively in operative connection with each other, acting as a legless helical spring which can be loaded in the opening direction 15 with blunt spring ends 16 . 17 formed and coaxial on the pivot bearing 3 is arranged.

When installed, the clamping lever 2 for tensioning the supplied arrange traction means by means of the coil spring 15 with a torsional moment M _T about the axis of rotation 5 of the pivot bearing 3 subjected to, whereby the tensioning roller over the clamping lever 2 spring-loaded on the traction means and thus the traction means is tensioned.

Between the outer lever-side turn 18 the coil spring 15 and the tension lever 2 is a bearing ring 19 made of a durable plastic. As in the enlarged section of 1 in 2 and the axial view of the bearing ring 19 in 3 is clearly visible, is the lever-side spring end 16 the torsion spring 14 over a wedge element 20 and a lever-proof driver 21 with the clamping lever 2 in connection. The wedge element 20 lies with an axially-radially aligned pressure surface 22 at the lever-side spring end 16 the coil spring 15 and with a radially outward of the lever-side spring end 16 tilted wedge surface 23 on an equally inclined wedge surface 24 of the driver 21 and with an external cylindrical friction surface 25 on a cylindrical inner wall 26 of the base housing 4 at.

In the present embodiment, the tensioning device 1 are the wedge element 20 and the driver 21 integral with the bearing ring 19 connected. The bearing ring 19 is near the driver 21 opposite the clamping lever 2 positively secured against rotation and against radial displacement, and between the wedge surface 23 of the wedge element 20 and the wedge surface 24 of the driver 21 with a separating slot 27 Mistake.

The positive connection of the bearing ring 19 with the clamping lever 2 is presently by an axially aligned inner radial groove 28 of the bearing ring 19 and an engaging axially extending outer radial web 29 of the clamping lever 2 educated. For damping vibrations of the coil spring 15 is the bearing ring also with sleeve segments 30 provided in the mounted state radially inward on the turns of the coil spring 15 issue.

To illustrate the balance of forces on the wedge element 20 are in 4a the on the wedge element 20 according to 3 represented effective forces. Normal, ie perpendicular to the printing surface 22 of the wedge element 20 the tangential spring force F _{F_T of} the spring end acts 16 the coil spring 15 , normal to the wedge surface 23 of the wedge element 20 the reaction force of the driver acts 21 on the supporting force F _{K_N of} the wedge element 20 , and normal or radial on the friction surface 25 of the wedge element 20 the reaction force of the cylindrical interior acts wall 26 of the base housing 4 on the radial contact force F _{K_R of} the wedge element 20 ,

At one regarding the torsion spring 14 resilient pivoting movement 31 of the clamping lever 2 In addition, the friction force F _{R_T} shown in solid _{lines acts} on the friction surface 25 of the wedge element 20 , In an opposing spring-out swinging motion 32 of the clamping lever 2 acts in the opposite direction, the dashed lines shown friction force F _{R_T} on the friction surface 25 of the wedge element 20 ,

In 4b is the static balance of forces at the wedge element 20 shown, which is at a certain position of the clamping lever 2 without setting a pivoting movement. In 4c is the dynamic balance of forces at the wedge element 20 shown, which is at a certain position of the clamping lever 2 during one with respect to the torsion spring 14 resilient pivoting movement 31 of the clamping lever 2 adjusts, resulting in an increase in the radial contact force F _{K_R of} the wedge element 20 and consequently an increase in the friction damping of the pivoting movement 31 results.

In 4d is the dynamic balance of forces at the wedge element 20 shown, which is at a certain position of the clamping lever 2 during one with respect to the torsion spring 14 springing out pivoting movement 32 of the clamping lever 2 adjusts, resulting in a reduction of the radial contact force F _{K_R of} the wedge element 20 and consequently a reduction in the frictional damping of the pivoting movement 32 established. This ensures that the clamping lever 2 an outward swinging of the traction means opposes an increased resistance, whereas a swinging inward of the traction means is opposed to a reduced resistance, so that at the clamping lever 2 mounted tension roller follows the movement of the traction means and remains in contact with this.

An alternative embodiment of the tensioning device according to the invention 1' is in 5 in a simplified, partially sectioned axial view looking from the base housing to the outer clamping lever 2 shown. The tension lever 2 is from the coil spring 15 with opposite direction of rotation to the clamping device 1 according to 1 to 3 subjected to the torsional moment M _T , whereby the tensioning roller 33 is sprung to an associated traction means and a resultant reaction force F _{Z_R} on the tension roller 33 or the tension lever 2 is produced. The wedge element 20 and the driver 21 are integral with the bearing ring as in the previously described embodiment 19 connected, which consists of an elastic and resistant plastic, between the outer lever-side winding 18 the coil spring 15 and the tension lever 2 is arranged as well as between the wedge surfaces 23 . 24 of the wedge element 20 and the driver 21 a separating slot exaggerated here 27 having.

For the most complete compensation of a by the reaction force F _{Z_R of} the traction means on the tensioning roller 33 caused tilting moment about a tilting axis of the pivot bearing are the wedge surfaces 23 . 24 of the wedge element 20 and the driver 21 aligned largely normal to the reaction force F _{Z_R} . The non-rotatable and radially fixed connection of the bearing ring 19 with the clamping lever 2 is present, as in 5 just hinted, in the form of a close to the driver 21 on the bearing ring 19 arranged axial bore 34 , one on the tension lever 2 arranged axial bore 35 and one in the axial bores 34 . 35 used bolt 36 educated. The lever-side axial bore 35 Can be applied depending on the application in different angular positions, so that the use of a largely identical clamping lever 2 in several different fixtures is possible.

A further embodiment of the tensioning device according to the invention 1'' is in 6a and 6b in each case in a simplified, partially sectioned axial view looking from the base housing to the outer clamping lever 2 shown. 6a shows the lever-side bearing ring 19 ' with the outer lever-side turn 18 the coil spring 15 while in 6b the tension lever 2 with the tension roller 33 is shown. The wedge element 20 is integral with the bearing ring 19 ' connected, the immediately adjacent to the wedge surface 23 of the wedge element 20 a radially continuous opening 37 having. The driver 21 with the local wedge surface 24 is in the present case practically in the clamping lever 2 ' integrated by placing this one through the wedge surface 24 limited radial groove 38 is provided, in the mounted state, an axial extension of the wedge element 20 with its wedge surface 23 intervenes. To the tension lever 2 ' to use even with a clamping device with opposite pivoting direction, is the radial groove 38 circumferentially opposite by another wedge surface 24 ' limited.

In 7 is a schematic axial view of the lever-side support of the reaction force F _{F_R of} the clamping lever 2 on the coil spring 15 over a slide shoe 39 represented, whereby an additional friction torque for damping a pivoting movement of the clamping lever 2 is produced. The sliding shoe 39 is about the axis of rotation 5 of the pivot bearing 3 from the lever-side spring end 16 arranged offset by about 90 °, lies radially inward on the outer lever-side turn 18 the coil spring 15 on, is in a radial guidance 40 of the clamping lever 2 guided radially movable, and lies with an external cylindrical friction surface 41 on a cylindrical inner wall 26 of the base housing 4 at. On the circumference of the lever-side spring end 16 turned side are the side walls 42 . 43 of the sliding shoe 39 and the radial guide 40 aligned radially-parallel. On the circumference of the lever-side spring end 16 facing side are the side walls 44 . 45 of the sliding shoe 39 and the radial guide 40 in contrast, as radially outward to the lever-side spring end 16 wedge-shaped wedge surfaces formed, whereby the effective friction torque at a relative to the coil spring 15 resilient pivoting movement 31 of the clamping lever 2 is reinforced.

In the schematic sectional view according to 8th is for the lever end of the coil spring 15 illustrates that the support of the reaction force F _{F_R of} the coil spring 15 alternatively also by an immediate contact of the outer lever-side turn 18 the coil spring 15 with the cylindrical inner wall 26 of the base housing 4 can be done. For this purpose, at least the outer lever-side turn 18 the coil spring 15 with a friction coating 46 Mistake. Advantageously, in this case, the coil spring 15 but completely with a friction coating 46 provided, as hereby an otherwise required corrosion protection treatment of the coil spring 15 can be omitted.

1

jig

1'

jig

1''

jig

2

clamping lever

2 '

clamping lever

3

pivot bearing

4

base housing

5

axis of rotation of clamping lever and pivot bearing

6

axis of rotation

7

serration

8th

bearing bolt

9

bearing hub

10

plain bearing bush

11

slide bearing disk

12

bearing plate

13

bearing plate

14

torsion spring

15

coil spring

16

lever-page spring end

17

housing-sided spring end

18

Outer lever side Winding of the coil spring

19

bearing ring

19 '

bearing ring

20

key member

21

takeaway

22

Printing surface of the key member

23

Wedge surface of the key member

24

Wedge surface of the follower

24 '

Wedge surface of the follower

25

Friction surface of the key member

26

inner wall in the base housing

27

separating slot of the bearing ring

28

radial groove of the bearing ring

29

radial web of the clamping lever

30

sleeve segment

31

pivotal movement of the clamping lever

32

pivotal movement of the clamping lever

33

idler

34

Axial bore of the bearing ring 19

35

axial bore in the cocking lever

36

bolt

37

Opening of the bearing ring 19 '

38

radial groove in the cocking lever

39

shoe

40

radial guide

41

Friction surface of the sliding shoe

42

Side wall of the sliding shoe

43

Side wall the radial guide

44

Side wall, wedge surface of the sliding shoe

45

Side wall, wedge surface the radial guide

46

friction coating the coil spring

F _{F_R}

Radial reaction force (from 2 . 20 ), Supporting force of the coil spring

F _{F_T}

Tangential spring force (from 15 . 20 )

F _{K_N}

Normal support force (from 20 . 21 )

F _{K_R}

Radial contact pressure (from 20 . 26 )

F _{R_T}

Tangential frictional force (from 20 . 26 )

F _{Z_R}

radial Reaction force of the traction device

M _T

Torsional moment (of 14 . 15 )

Claims (20)

Tensioning device of a traction mechanism drive, with a via a pivot bearing ( 3 ) rotatable on a base housing ( 4 ) and radially spaced from the axis of rotation ( 5 ) of the pivot bearing ( 3 ) with a rotatable tension roller ( 33 ) provided tensioning lever ( 2 ), which by means of a thighless coil spring ( 15 ), coaxial with the pivot bearing ( 3 ) and at the spring ends ( 16 . 17 ) on the housing side with the base housing ( 4 ) and lever side with the clamping lever ( 2 ) in operative connection torsion spring ( 14 ) with a torsional moment (M _T ) about the axis of rotation ( 5 ) of the pivot bearing ( 3 ) is acted upon, wherein the pivot bearing ( 3 ) by a bearing pin ( 8th ), a bearing hub ( 9 ) and at least one between the bearing pin ( 8th ) and the bearing hub ( 9 ) arranged plain bearing bush ( 10 ), and wherein a central radial force application plane of the tensioning roller to a central radial bearing plane of the pivot bearing ( 3 ) is axially spaced, characterized in that the lever-side or housing-side spring end ( 16 ) of the torsion spring ( 14 ) over at least one wedges lement ( 20 ) and a lever-proof driver ( 21 ) with the clamping lever ( 2 ), wherein the wedge element ( 20 ) with an axially-radially aligned pressure surface ( 22 ) on the lever-side spring end ( 16 ) of the coil spring ( 15 ) is applied, with a radially outward of the lever-side spring end ( 16 ) sloping wedge surface ( 23 ) on an equally inclined wedge surface ( 24 ) of the driver ( 21 ) is applied, and with an outer cylindrical friction surface ( 25 ) on a cylindrical inner wall ( 26 ) of the base housing ( 4 ) is present. Clamping device according to claim 1, characterized in that the driver ( 21 ) with respect to the axis of rotation ( 5 ) of the pivot bearing ( 3 ) is arranged circumferentially such that the wedge surfaces ( 23 . 24 ) of the wedge element ( 20 ) and the driver ( 21 ) largely normal to a resulting reaction force (F _{Z_R} ) of a traction device on the tensioning roller ( 33 ) are aligned. Clamping device according to claim 1 or 2, characterized in that the angle of inclination of the wedge surfaces ( 23 . 24 ) of the wedge element ( 20 ) and the driver ( 21 ) opposite the printing surface ( 22 ) of the wedge element ( 20 ) is in a range between 30 ° and 60 °. Clamping device according to at least one of claims 1 to 3, characterized in that the friction surface ( 25 ) of the wedge element ( 20 ) and / or the cylindrical inner wall ( 26 ) of the base housing ( 4 ) is provided with a friction lining. Clamping device according to at least one of claims 1 to 4, characterized in that the entire wedge element ( 20 ) consists of a resistant and friction-resistant plastic. Clamping device according to at least one of claims 1 to 5, characterized in that the wedge element ( 20 ) in one piece with an open bearing ring ( 19 ) connected between the outer lever-side winding ( 18 ) of the coil spring ( 15 ) and the tensioning lever ( 2 ) spaced from the wedge element (Fig. 20 ) relative to the tensioning lever ( 2 ) is positively secured against rotation, and immediately adjacent to the wedge surface ( 23 ) of the wedge element ( 20 ) is completely open. Clamping device according to claim 6, characterized in that the wedge element ( 20 ) at least partially axially outside of the bearing ring ( 19 ' protrudes) and in one with the lever-side wedge surface ( 24 ' ) provided radial groove ( 38 ) of the clamping lever ( 2 ) intervenes. Clamping device according to claim 7, characterized in that the radial groove ( 38 ) of the clamping lever ( 2 ) in the circumferential direction on both sides with a wedge surface ( 24 . 24 ' ) is provided. Clamping device according to at least one of claims 1 to 5, characterized in that the wedge element ( 20 ) and the driver ( 21 ) in one piece with a slotted bearing ring ( 19 ) connected between the outer lever-side winding ( 18 ) of the coil spring ( 15 ) and the tensioning lever ( 2 ), which is close to the driver ( 21 ) relative to the tensioning lever ( 2 ) is positively secured against rotation and against a radial displacement, and between the wedge surface ( 23 ) of the wedge element ( 20 ) and the wedge surface ( 24 ) of the driver ( 21 ) with a separating slot ( 27 ) is provided. Clamping device according to claim 9, characterized in that the positive connection of the bearing ring ( 19 ) with the clamping lever ( 2 ) by an axial bore ( 34 . 35 ) and one in the axial bores ( 34 . 35 ) ( 36 ) is formed. Clamping device according to claim 9, characterized in that the positive connection of the bearing ring ( 19 ) with the clamping lever ( 2 ) by an axially extending inner radial groove ( 28 ) of the bearing ring ( 19 ) and an engaging in this axially extending outer radial web ( 29 ) of the clamping lever ( 2 ) is formed. Clamping device according to at least one of claims 1 to 11, characterized in that the housing-side spring end ( 17 ) of the torsion spring ( 14 ) via a wedge element and a housing-fixed driver with the base housing ( 4 ), wherein the wedge element with an axially-radially aligned pressure surface on the housing-side spring end ( 17 ) of the coil spring ( 15 ) is applied, with a radially outward of the housing-side spring end ( 17 ) inclined inclined wedge surface rests against an equally inclined wedge surface of the driver, and with an outer cylindrical friction surface on a cylindrical inner wall of the clamping lever ( 2 ) is present. Clamping device according to claim 12, characterized in that the housing-fixed driver with respect to the axis of rotation ( 5 ) of the pivot bearing ( 3 ) is arranged circumferentially such that an imaginary, the radial contact force (F _{K_R} ) of the wedge element containing radial surface largely parallel to the resulting reaction force (F _{Z_R} ) of the traction means on the tension roller ( 33 ) is aligned. Clamping device according to at least one of claims 1 to 13, characterized in that the lever-side support of the reaction force (F _{F_R} ) the clamping lever ( 2 ) on the coil spring ( 15 ) via a sliding shoe ( 39 ), which is about the axis of rotation ( 5 ) of the pivot bearing ( 3 ) from the lever-side spring end ( 16 ) is arranged offset by about 90 °, radially inward on the outer lever-side winding ( 18 ) of the coil spring ( 15 ) is present, in a radial guide ( 40 ) of the clamping lever ( 2 ) is guided radially movable, and with an outer cylindrical friction surface ( 41 ) on a cylindrical inner wall ( 26 ) of the base housing ( 4 ), wherein the sliding shoe ( 39 ) and the radial guidance ( 40 ) circumferentially on the lever-side spring end ( 16 ) facing side in each case a radially outward to the lever-side spring end ( 16 ) wedge surface ( 44 . 45 ) exhibit. Clamping device according to at least one of claims 1 to 14, characterized in that the housing-side support of the reaction force (F _{F_R} ) of the base housing ( 4 ) on the coil spring ( 15 ) takes place via a sliding shoe, which is about the axis of rotation ( 5 ) of the pivot bearing ( 3 ) from the housing-side spring end ( 17 ) is arranged offset back by about 90 °, radially inwardly on the outer housing-side winding of the coil spring ( 15 ) rests in a radial guide of the base housing ( 4 ) is guided radially movable, and with an outer cylindrical friction surface on a cylindrical inner wall of the clamping lever ( 2 ), wherein the sliding shoe and the radial guide circumferentially on the housing-side spring end ( 17 ) facing side in each case a radially outward to the housing side spring end ( 17 ) have wedge surface inclined. Clamping device according to claim 14 or 15, characterized in that the angle of inclination of the wedge surfaces of the sliding shoe and the radial guide relative to an imaginary, the axis of rotation ( 5 ) of the pivot bearing ( 3 ) and the outer cylindrical friction surface of the sliding shoe is approximately in a bisecting radial plane in a range between 30 ° and 60 °. Clamping device according to at least one of claims 14 to 16, characterized in that the sliding shoe ( 39 ) in one piece with the associated bearing ring ( 19 ) connected is. Clamping device according to at least one of claims 1 to 13, characterized in that the lever-side support of the reaction force (F _{F_R} ) of the clamping lever ( 2 ) on the coil spring ( 15 ) via an immediate contact of one about the axis of rotation ( 5 ) of the pivot bearing ( 3 ) from the lever-side spring end ( 16 ) from about 90 ° back portion of the outer lever-side winding ( 18 ) of the coil spring ( 15 ) with a cylindrical inner wall ( 26 ) of the base housing ( 4 ), wherein at least the outer lever-side winding ( 18 ) of the coil spring ( 15 ) and / or the cylindrical inner wall ( 26 ) of the base housing ( 4 ) with a friction coating ( 46 ) is provided. Clamping device according to at least one of claims 1 to 13 or 18, characterized in that the housing-side support of the reaction force (F _{F_R} ) of the base housing ( 4 ) on the coil spring ( 15 ) via an immediate contact of one about the axis of rotation ( 5 ) of the pivot bearing ( 3 ) from the housing-side spring end ( 17 ) from about 90 ° back portion of the outer housing side winding of the coil spring ( 15 ) with a cylindrical inner wall of the clamping lever ( 2 ), wherein at least the outer housing-side turn of the coil spring ( 15 ) and / or the cylindrical inner wall of the clamping lever ( 2 ) with a friction coating ( 46 ) is provided. Clamping device according to claim 18 or 19, characterized in that the helical spring ( 15 ) completely with a friction coating ( 46 ) is provided.