DE102008014325A1 - Belt tensioner for motor vehicle, has torsion spring formed as coil spring whose end center spaced to swivel bearing plane so that tilting torques of tangential spring force and resulting reaction force cancel each other around tilting axis - Google Patents

Abstract

The tensioner (1) has a damping device with a flat spiral spring (15), and a torsion spring (11) formed as an arm-less coil spring (12) with edges spring ends (13, 14). A center of the end (13) is axially spaced to a middle radial bearing plane (21) of an swivel bearing (3) so that tilting torques of a tangential spring force (Ff-t) of the coil spring and the resulting reaction force (Fz-r) of a power transmission belt cancel each other around a tilting axis (22). The axis intersects a rotation axis (5) of the bearing in the plane and is perpendicular to the spring and reaction forces.

Description

Field of the invention

The The invention relates to a belt tensioner, with an over a pivot bearing rotatably mounted on a base housing and radially spaced from the axis of rotation of the pivot bearing with a rotatable tensioner provided tension lever, which by means of a Coil spring formed, arranged coaxially to the pivot bearing, and at the two spring ends on the housing side with the base housing and lever side associated with the tension lever torsion spring acted upon by a torsional moment about the axis of rotation of the pivot bearing is, wherein the pivot bearing at least one bearing pin and a Bearing hub comprises, as well as with a damping device, the one damping sleeve and one adapted to the damping sleeve Band spring comprises, wherein the band spring between the damping sleeve and torsion spring is arranged and wherein the band spring and the Torsion spring are connected in series, with the band spring with one end against the cocking lever and with its other end against one end of the torsion spring is supported, the other end the torsion spring is clamped against the base housing.

Background of the invention

From the DE 101 31 916 A1 a belt tensioner is known in which a band spring encloses a damping bushing, wherein both are arranged at a distance from a helical torsion spring, which is located on a larger radius and is connected to a rotationally secured to the receiving housing and the other with the hub. The spring force of the torsion spring is transmitted via a roller carrier and a roller as a biasing force on a tensioning belt, wherein the damping mechanism fulfills the task of calming the described spring-mass system and to avoid undesirable belt vibrations. The attenuation here is clearly asymmetrical, with a higher attenuation when the band spring moves in and a lower attenuation when the band spring opens. Such a belt tensioner can provide satisfactory, but not optimal, damping rates in many cases.

From the DE 696 12 174 T1 For example, a belt tensioner is known which has a pivot arm which is attached to an offset cylinder part which supports the pivot arm and is rotatable about a pivot pin fixed to a base. A arranged on the pivot pin sleeve-like bush has a bearing surface which carries the cylinder part. Attached to the pivot arm is a pulley which engages a belt of a belt drive system and receives a belt load which generates a belt force component for transmission to the cylinder part. The hub load and the normal force component generated by the damping mechanism are held by at least one or two bushings having two axially spaced bearing surfaces. The bushings have an axial length by which the bearing surfaces are sized for such average pressure contact that each bearing surface wears radially at substantially the same rate. Due to the largely equal radial rate of wear of La gerflächen the pulley alignment over the expected life of the clamping device should be ensured. A similar solution is from the DE 600 16 031 T2 known.

Moreover, from the DE 10 2004 047 422 A1 a belt tensioner having a substantially cylindrical receiving housing and a hub coaxially inserted therein, said receiving housing and hub are rotatably supported against each other and supported with a helical torsion spring against each other with bias, and with a damping device having a circumferentially slotted damping bushing and one to the damping bushing adapted band spring comprises. The damping bushing is located on the inside of a housing connected to the hub of a tensioning arm of the belt tensioner, wherein the band spring between the damping bushing and torsion spring, in such a way that the band spring and the torsion spring are connected in series, wherein the torsion spring on the stationary housing of the belt tensioner and the band spring is supported on the housing of the tensioning arm.

These Arrangement has the advantage that a very compact and space-saving Structure of the belt tensioner is made possible. However, the Friction work between the moving with the clamping arm or clamping lever Friction lining of the damping bush and the fixed housing the belt tensioner performs, what in terms of oscillating Movements of the tensioner arm to increased wear and tear thus leading to premature failure of the belt tensioner can. Furthermore, it can by the band spring and by with her in Actively connected damping sleeve to cogging moments or due to friction delays, which can lead to unwanted vibrations. One particularly serious disadvantage is that the two-piece plain bearing bushing undergoes an edge load, so that this plain bearing bushing wears out relatively quickly.

Finally, out of the DE 10 2006 014 942 A1 the Applicant a tensioning device of a traction mechanism known, with a rotatably mounted on a pivot bearing on a base housing and radially spaced from the axis of rotation of the pivot bearing provided with a rotatable tension roller Tensioning lever which is acted upon by means of a helical spring, arranged coaxially to the pivot bearing and at both spring ends housing side with the base housing and the lever side associated with the tensioning lever torsion spring with a torsional moment about the axis of rotation of the pivot bearing, wherein the pivot bearing a bearing pin, a bearing hub and at least one plain bearing bush disposed between the bearing pin and the bearing hub, and wherein a central radial force application plane of the tensioning roller is axially spaced from a central radial bearing plane of the pivot bearing.

These Clamping device is also characterized in that the torsion spring as a legless helical spring resilient in the opening sense is formed with blunt spring ends whose lever-side spring end at an axially-radially aligned stop surface of a with the clamping lever connected driver, wherein the driver with respect to the axis of rotation of the pivot bearing circumferentially is arranged such that the stop surface normal to a resultant reaction force of a traction means on the tension roller aligned, wherein the support of a reaction force of the clamping lever on the coil spring relative to the base housing takes place, and wherein the center of the lever-side spring end to the Middle bearing plane of the pivot bearing axially spaced so is that the tilting moments of a over the stop surface on the clamping lever effective tangential spring force of the coil spring and the effective over the tension roller on the clamping lever resulting Reaction force of the traction means about an imaginary, perpendicular to the Spring force and the reaction force the axis of rotation of the pivot bearing in the middle bearing plane perpendicularly intersecting tilting axis mutually cancel.

Object of the invention

Of the Invention has for its object to provide a belt tensioner, which eliminates the disadvantages described. In particular, a should inexpensive to manufacture and compact constructed belt tensioner be created at which vibration damping effectively and be produced wear.

Summary of the invention

Of the Invention is based on the finding that the asked Task in a surprisingly simple way thereby lets solve that the force-effective components the belt tensioner are matched to one another such that the system is balanced, so storage instead of a Edge load experiences a much more gentle line load.

The invention is therefore based on a belt tensioner, 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 helical spring, coaxial with the pivot bearing, and at both Spring ends on the housing side with the base housing and the lever side associated with 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 comprises at least one bearing pin and a bearing hub, and with a damping device comprising a damping sleeve and a to the Damping sleeve adapted band spring comprises, wherein the band spring between the damping sleeve and torsion spring is arranged and wherein the band spring and the torsion spring are connected in series, wherein the band spring with one end against the clamping lever and with its other E hands against one end of the torsion spring, and wherein the other end of the torsion spring is braced against the base housing. In addition, it is provided that the torsion spring is designed as a resilient in the open sense legless coil spring with blunt spring ends, and that the support of a reaction force of the clamping lever on the coil spring relative to the base housing, wherein the center of the lever-side spring end to the central bearing plane of the pivot bearing axially is spaced so that the tilting moments of an acting on the tensioning lever on the tension spring tangential spring force of the coil spring and acting on the tensioning roller on the tensioning lever resulting reaction force of the traction means about an imaginary, perpendicular to the spring force and the reaction force the axis of rotation of the pivot bearing in the cancel each other in the middle bearing plane perpendicularly intersecting tilting axis.

By this construction is advantageously achieved that the friction lining of the damping sleeve, although, as already from the DE 10 2004 047 422 A1 is known, acts against the oscillating lever, however, the tangential force of the spring is designed by the inventive design in relation to the resultant force on the tension roller. By positioning the tangential force in the direction and height depending on the clamping force, the bearing load of the plain bearing bush can be changed from a conventional edge load to a uniform line contact. As a result, a better utilization of the sliding bearing or plain bearing bush is possible and it can be achieved a longer life. To control a dynamic tumbling of the lever, the axial force of the torsion spring is used to assist. As a result, a balance of the force-dynamic components of the belt tensioner ge create, which can significantly increase the life of the belt tensioner.

By this balance will make it even possible on one Sliding bearing or a plain bearing bush without doing so to violate the Winkligkeitsforderung on the tensioner. The episode is a significant cost savings.

In addition, it can be provided that the torsional moment M _{T is introduced} via the lever-side spring end of the coil spring in the form of a tangential spring force F _{F_T} in the angled end of the _band spring and the free end of the _band spring in the clamping lever, wherein the effective torsional moment M _T from of the tangential spring force F _{F_T} multiplied by half the diameter D _F / 2 of the coil spring, so that for this the equation M _T = F _{F_T} × D _F / 2 applies.

In another practical development can be provided that against the torsional moment M _{T of} the coil spring effective in a central radial force _{application plane} of the tension roller resulting reaction force F _{Z_R of} the traction means on the tension roller multiplied by the effective, right-angled distance R _{H_eff} the axis of rotation of the tension roller to the The axis of rotation of the pivot bearing holds the balance, so that for the moment equilibrium the equation M _T = F _{F_T} × D _F / 2 = F _{Z_R} × R _{H_eff} applies.

Another embodiment of the invention provides that the radially inwardly bent end of the hinge spring with respect to the axis of rotation of the pivot bearing is circumferentially arranged such that the stop surface formed by the bent end of the coil _spring aligned normal to the resulting reaction force F _{Z_R of} the traction means on the tension roller is.

Likewise, it is within the scope of the invention to provide that the middle of the lever-side spring end to the central bearing plane of the pivot bearing has such an axial distance L ₂ that the tilting moment M _K = F _{F_T} exerted by the tangential spring force F F _T about the tilt axis on the tension lever × L ₂ with opposite direction of rotation corresponds to the _overturning moment M _K = F _{Z_R} × L _{1 of} the reaction force F _{Z_R of} the traction means on the tensioning lever, so that the moment equilibrium M _K = F _{Z_R} × L ₁ = F _{F_T} × L ₂ applies.

In a particularly practical development of the invention, it is provided that the diameter D _{FB of} the spring band is smaller or larger than the diameter D _{F of} the torsion spring.

Also particularly advantageous is an embodiment of the invention, which is characterized in that for the generated by the spring band radial force F _FB , acting on the damping sleeve radial force F _DH , for the diameter D _{DH of} the damping sleeve and for the voltage applied to the clamping lever Forces, the relation F _FR = F F _{- T} ± F _FB - ΣF _DH holds, where ΣF _DH = (F F _{- R} ± F _FB ) × μ.

It is also within the scope of the invention to provide that the pivot bearing the bearing pin, the bearing hub and one between the bearing pin and the bearing hub arranged plain bearing bush comprises, wherein the plain bearing bush made of a plastic.

These Design can also be supplemented by that the plain bearing bush made of a plastic with an internal, So there is encapsulated lubricant.

A Development of the latter embodiment of the invention sees prior to that said lubricant being replaced by PA46PTFE15 (high temperature polyamide + Polytetrafluoroethylene) or by a plastic with a chemical bonded PTFE (polytetrafluoroethylene) with a proportion between 5% and 30% is formed.

Other practical embodiments of the invention are characterized by in that a circumferential sealing lip is molded onto the plain bearing bush.

Also in the context of the invention it is to provide that the plain bearing bush radially outwardly has a conical lateral surface, at which the bearing hub of the clamping arm with a radially inner conical Lateral surface is supported radially.

In a particularly practical supplement of the invention provided that the bearing pin integral with the Aluminum die-cast existing base housing connected is.

In another practical development can be provided that the damping sleeve in one piece to the Band spring is formed.

Especially finally advantageous is an embodiment of the invention, which is characterized in that the damping sleeve by injection or rolling in one piece with the band spring connected is.

Brief description of the drawings

The Invention will become more apparent in the following with reference to the accompanying drawings explained. It shows

1 a first embodiment of a belt tensioner according to the invention in longitudinal cut,

2 the belt tensioner the 1 in cross section in the region of the damping device, and

3 A second embodiment of a belt tensioner according to the invention in longitudinal section.

Detailed description the drawing

In the 1 and 2 is a first embodiment of an inventive, serving as a tensioning device of a traction drive belt tensioner 1 shown in longitudinal section and in cross section. In a so-called offset or Z arrangement is a tension lever 2 over a pivot bearing 3 rotatable on a base housing 4 stored, and radially from the axis of rotation 5 of the pivot bearing 3 spaced with a rotatable tensioner 6 Mistake. The pivot bearing 3 is from a bearing pin 7 , a warehouse hub 8th and one between the bearing pin 7 and the warehouse hub 8th arranged plain bearing bush 9 formed, in the present case the bearing pin 7 integral with the aluminum base housing 4 connected and the bearing hub 8th a component of the clamping lever 2 is. The base housing 2 is for attachment to another housing, eg. B. a crankcase or a control housing of a drive motor of a motor vehicle with a central bore 10 provided through which, for example, a fastening screw can be passed.

According to the invention, one between the clamping lever 2 and the base housing 4 arranged torsion spring 11 as a legless helical spring resilient in the opening sense 12 with blunt spring ends 13 and 14 educated. The coil spring 12 is coaxial with the pivot bearing 3 arranged and stands with a spring end 14 positive fit axially on the housing side with the base housing 4 in connection. Lever side supports the legless spring end 13 the torsion spring 11 , this in 2 is clearly recognizable, on a band spring 15 from whose free end 16 is bent radially inward and the other end 17 secured against rotation on the clamping lever 2 is fixed. The torsion spring 11 and the band spring 15 are in this way between the base housing 4 and the warehouse hub 8th connected in series. The feathers 11 and 15 are biased here, wherein they are radially drawn, so are widened. Radially outside the band spring 15 is a damping sleeve 18 indirectly from the torsion spring 11 and directly from the band spring 15 is acted upon radially with a force F _FB and the axially above and radially inside the base housing 4 supported.

The base housing 4 moreover, has a known, but not shown, rotation stop, which with an inner recess, not shown on the clamping arm 2 interacts. In this way, the base housing 4 and the camp hub 8th the work area according to only limited against each other rotatable.

For tensioning a tension roller when installed 6 partially entraining traction means of a traction mechanism drive is the tensioning lever 2 by means of the coil spring 12 with a torsional moment M _{T of} the coil spring 12 around the axis of rotation 5 of the pivot bearing 3 acted upon. The torsional moment M _T is on the lever-side spring end 13 the coil spring 12 in the form of a tangential spring force F _{F_T} first in the angled end 16 the band spring 15 and from there under extension of the band spring 15 about the free end 17 the band spring 15 in the cocking lever 2 initiated. The effective torsional _moment M _T thus results from the tangential spring force F _{F_T} multiplied by half the diameter D _F / 2 of the coil spring 12 (ie M _T = F _{F_T} × D _F / 2).

Against the torsional moment M _{T of} the coil spring 12 holds them in a middle radial force application plane 19 the tension roller 6 effective resultant reaction force F _{Z_R of} the traction means on the tensioning roller 6 multiplied by the effective, ie rectangular distance R _{H_eff} the axis of rotation 20 the tension roller 6 to the rotation axis 5 of the pivot bearing 3 the equilibrium such that for the _{instantaneous} equilibrium of the tensioning device the equation M _T = F _{F_T} × D _F / 2 = F _{Z_R} × R _{H_eff} holds.

Due to its axial distance L ₁ to a central radial bearing plane 21 of the pivot bearing 3 the resultant reaction force F _{Z_R of} the pulling means also has a tilting moment M _K = F _{Z_R} × L ₁ about an imaginary tilting axis 22 result, perpendicular to the reaction force F _{F_T of} the traction means and the axis of rotation 5 of the pivot bearing 3 in the middle camp level 21 which, without a torque compensation to a high local edge load of the plain bearing bush 9 and consequently premature wear thereof or the belt tensioner 1 would lead.

Therefore, the radially inwardly bent end 16 the band spring 15 with respect to the axis of rotation 5 of the pivot bearing 3 circumferentially arranged such that by the bent end 16 the band spring 15 formed stop surface normal to the resulting reaction force F _{Z_R of} the traction means on the tension roller 6 is aligned, and the center of the lever-side spring end 13 to the middle storage level 21 of the pivot bearing 3 such an axial distance L ₂ , that by the tangential spring force F _{F_T} about the tilt axis 22 on the cocking lever 2 applied tilting moment M _K = F _{F_T} × L ₂ with opposite direction of rotation the tilting moment M _K = F _{Z_R} × L _{1 of} the reaction force F _{Z_R of} the traction means on the clamping lever 2 corresponds, whereby a torque-free load of the plain bearing bushing 9 is achieved. As a result, the moment equilibrium M _K = F _{Z_R} × L ₁ = F _{F_T} × L _{2 holds} .

Due to the valid moment and force _{relationships} with M _T = F _{F_T} × D _F / 2 = F _{Z_R} × R _{H_eff} or F _{F_T} / F _{Z_R} = R _{H_eff} / D _F / 2 and M _K = F _{Z_R} × L ₁ = F _{F_T} × L ₂ or F _{F_T} / F _{Z_R} = L ₁ / L ₂ may be required for torque compensation axial distance L _{2 of} the lever-side spring end 13 the coil spring 12 to the middle storage level 21 of the pivot bearing 3 with otherwise given dimensions according to the equation L ₂ = L ₁ × D _F / (2 × R _{H_eff} ) can be determined.

The lever-side support of the reaction force F _{F_R of} the clamping lever 2 on the tangential spring force F _{F_T of} the coil spring 12 occurs without influencing the moment equilibrium of the clamping lever 2 opposite the base housing 4 about the arrangement of strip spring 15 and damping sleeve 18 , which oscillations of the tension lever acted upon by the traction means 2 on the belt tensioner 1 in addition to the plain bearing bush 9 should compensate. This results in the most uniform possible force distribution in the tangential, axial and radial directions both on the plain bearing bushing 9 , the damping sleeve 18 , as well as on tension arm 2 and base housing 4 and in order to create a fully balanced system in terms of power, the torsion spring 11 and the band spring 15 in terms of the diameter, the length and the balance of power optimally matched.

Here, the diameter D _{FB of} the spring band 15 smaller or larger than the diameter D _{F of} the torsion spring 11 , For the balance of power between torsion spring 11 , Ribbon spring 15 , Damping sleeve 18 and the tension lever 2 Ideally, the relationship applies F F_R = F F_T ± F FB - ΣF DH . With F DH = (F F_R ± F FB ) × μ

Here, F _{FB is} the spring band 15 generated radial force and F _DH acting on the damping sleeve radial force, which in 2 with several force arrows F _{DH is} indicated. D _DH is the diameter of the damping sleeve 18 ,

To calculate the clamping torque, the relationship F _{F_R} × R _{H_eff} applies here.

To calculate the friction torque applies

By positioning the tangential force F _{F_T} in the direction and height depending on the clamping force, the bearing load of the plain bearing _bush 9 be changed from a usual in the art edge load on a regular line contact. As a result, a better utilization of the plain bearing is possible and it can have a longer life of the plain bearing bushing 9 and thus the belt tensioner 1 be achieved. To the dynamics of the clamping lever 2 To keep under control, the axial force of the torsion spring 11 used for support.

By balancing by a balanced design of the effective forces by adjusting the force components of the torsion spring 11 , the band spring 15 and the damping sleeve 18 it is even possible with optimal design, on the plain bearing bush 9 to do without the Winkligkeitsforderung on the tensioner 6 to hurt. But at least it is possible, compared to conventional solutions less expensive or expensive designed plain bearing bushing 9 to use plastic, since the usual maximum surface pressure at the sliding bearing edges no longer occurs.

So it is possible to have an in 1 illustrated plain bearing bush 9 made of plastic with an internal, so used in the plastic lubricant, the lubricant may be selected for example by a plastic such as PA46PTFE15 (high temperature polyamide + polytetrafluoroethylene). Since the lubricant is not always present in sufficient quantities on the surface of these materials, a plastic with chemically bound polytetrafluoroethylene (PTFE) can alternatively be selected, here the lubricant is available directly on the surface. By using plastic with chemically coupled PTFE, the noise potential is significantly reduced even with reduced PTFE contents of up to 15%, whereby the strength of the material is higher than with conventional mixtures. This also PTFE shares are up to 30% in question.

To the sealing effect of existing from such a plastic plain bearing bush 9 against the tension arm 2 is to increase the plain bearing bushing 9 a circumferential sealing lip 23 molded.

In 3 is a second embodiment of the belt tensioner according to the invention 1 shown in longitudinal section, which largely the in 1 illustrated embodiment of the belt tensioner 1 corresponds and uses the same reference numerals for the same parts. Also with this Rie menspanner 1 is a tension lever 2 over a pivot bearing 3 rotatable on a base housing 4 stored, and radially from the in 3 not shown rotation axis of the pivot bearing 3 spaced provided with a rotatable tension roller, not shown. The pivot bearing 3 is also made of a bearing pin 7 , a warehouse hub 8th and one between the bearing pin 7 as well as the warehouse hub 8th arranged plain bearing bush 9 ' formed, wherein the bearing pin 7 integral with the base housing 4 connected, and the bearing hub 8th a component of the clamping lever 2 is. The base housing 4 is for attachment to another housing, eg. B. a crankcase or a control housing of a drive motor of a motor vehicle with a central bore 10 provided by a fixing screw 24 passed through.

According to the invention is also one between the clamping lever 2 and the base housing 4 effectively arranged torsion spring 11 as a legless helical spring resilient in the opening sense 12 with blunt spring ends 13 and 14 educated. The coil spring 12 is coaxial with the pivot bearing 3 arranged and stands with a spring end 14 positive fit axially on the housing side with the base housing 4 in connection. The lever end is supported by the spring end 13 the torsion spring 11 on a ribbon spring 15 from whose free end 16 is bent radially inward and the other end 17 secured against rotation on the clamping lever 2 is fixed. The torsion spring 11 and the band spring 15 are in this way between the base housing 4 and the warehouse hub 8th connected in series. The feathers 11 and 15 are biased here, wherein they are radially raised, ie expanded. Radially outside the band spring 15 is a damping sleeve 18 indirectly from the torsion spring 11 and directly from the band spring 15 is applied radially with a force, and the axially above and radially inside the base housing 4 supported. With regard to the balance of power also apply to the in 3 illustrated embodiment with respect to 1 and 2 made statements.

In contrast to the first embodiment, the belt tensioner has a preferably slotted plain bearing bush ( 9 ' ) on. This can be created a backlash-free storage. This has radially outwardly a truncated conical or conical lateral surface 25 on. On this lateral surface 25 the bearing hub is supported 8th of the tensioning arm 2 with a radially inner frustoconical or conical lateral surface 26 radially off. By this configuration, torsion spring can be 11 and tension arm 2 even better balance, because the conical plain bearing bushing 9 ' and the conical seat 26 of the tensioning arm 2 make balancing even easier. The plain bearing bush 9 ' can according to the plain bearing bush 9 of the 1 and 2 consist of a plastic with embedded lubricants.

As a supplement to the embodiments described above can be provided, the damping sleeve 18 in one piece to the band spring 15 to form, namely the fact that the material of the damping sleeve 18 , For example, a polymer plain bearing material, to the band spring 15 molded or the band spring 15 of the material of the damping sleeve 18 is overmoulded. However, it is also possible, for example, a plastic with dry lubricant to the band spring 15 roll to produce in this way a metal-polymer composite part. Of course, the invention can also be applied to so-called inline clamping units (Pulley bearings).

1

tensioner

2

clamping lever

3

pivot bearing

4

base housing

5

axis of rotation

6

idler

7

bearing bolt

8th

bearing hub

9

plain bearing bush

9 '

plain bearing bush

10

central bore

11

torsion spring

12

coil spring

13

spring end

14

spring end

15

band spring

16

Free end of the band spring 15

17

End of the band spring 15

18

damping sleeve

19

radial Force application level

20

axis of rotation

21

middle radial bearing plane

22

tilt axis

23

sealing lip

24

fixing screw

25

Conical surface of the plain bearing bush 9 '

26

Conical lateral surface of the bearing hub 8th

D _F

Diameter of the coil spring 12

F _{F_R}

radial reaction force of the coil spring 12

F _{F_T}

Tangential spring force of the coil spring 12

F _{Z_R}

radial reaction force

L ₁

axial distance

L ₂

axial distance

R _{H_eff}

more effective radial distance

F _FB

radial reaction force of the spring band 15

F _DH

Radial reaction force on the damping sleeve 18

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 10131916 A1 [0002]
• - DE 69612174 T1 [0003]
• - DE 60016031 T2 [0003]
• - DE 102004047422 A1 [0004, 0011]
• DE 102006014942 A1 [0006]

Claims (15)

Belt tensioner ( 1 ), 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 ( 6 ) provided tensioning lever ( 2 ), which by means of a coil spring ( 12 ), coaxial with the pivot bearing ( 3 ), and at both spring ends ( 13 . 14 ) on the housing side with the base housing ( 4 ) and lever side with the clamping lever ( 2 ) associated torsion spring ( 11 ) 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 ) at least one bearing pin ( 7 ) and a bearing hub ( 8th ), and with a damping device comprising a damping sleeve ( 18 ) and one to the damping sleeve ( 18 ) adapted strip spring ( 15 ), wherein the band spring ( 15 ) between damping sleeve ( 18 ) and torsion spring ( 11 ) and wherein the band spring ( 15 ) and the torsion spring ( 11 ) are connected in series, wherein the band spring ( 15 ) with one end ( 17 ) against the tensioning lever ( 2 ) and with its other end ( 16 ) against an end ( 13 ) of the torsion spring ( 11 ), the other end ( 14 ) of the torsion spring ( 11 ) against the base housing ( 4 ), characterized in that the torsion spring ( 11 ) as a legless helical spring resilient in the open sense (US Pat. 12 ) with blunt spring ends ( 13 . 14 ), and that the support of a reaction force (F _{F_R} ) of the clamping lever ( 2 ) on the coil spring ( 12 ) relative to the base housing ( 4 ), wherein the middle of the lever-side spring end ( 13 ) to the middle storage level ( 21 ) of the pivot bearing ( 3 ) is axially spaced such that the tilting moments (M _K ) one over the band spring ( 15 ) on the cocking lever ( 2 ) effective tangential spring force (F _{F_T} ) of the coil spring ( 12 ) and the over the tension pulley ( 6 ) on the cocking lever ( 2 ) effective reaction force (F _{Z_R} ) of the traction means about an imaginary perpendicular to the spring force (F _{F_T} ) and the reaction force (F _{Z_R} ) the axis of rotation ( 5 ) of the pivot bearing ( 3 ) in the middle storage level ( 21 ) vertically crossing tilting axis ( 22 ) cancel each other out. Belt tensioner according to claim 1, characterized in that the torsional moment (M _T ) over the lever-side spring end ( 13 ) of the coil spring ( 12 ) in the form of a tangential spring force (F _{F_T} ) in the angled end ( 16 ) of the band spring ( 15 ) and the free end ( 17 ) of the band spring ( 15 ) in the cocking lever ( 2 ), wherein the effective torsional _moment (M _T ) of the tangential spring force (F _{F_T} ) multiplied by half the diameter (D _F / 2) of the coil spring ( 12 ), so that the equation M _T = F _{F_T} × D _F / 2 holds for this. Belt tensioner according to claim 1 or 2, characterized in that against the torsional moment (M _T ) of the helical spring ( 12 ) in a middle radial force application plane ( 19 ) of the tension roller ( 6 ) effective reaction force (F _{Z_R} ) of the traction means on the tension roller ( 6 ) multiplied by the effective, rectangular distance (R _{H_eff} ) of the axis of rotation ( 20 ) of the tension roller ( 6 ) to the axis of rotation ( 5 ) of the pivot bearing ( 3 ) holds the equilibrium, so that for the _{instantaneous} equilibrium the equation M _T = F _{F_T} × D _F / 2 = F _{Z_R} × R _{H_eff} holds. Belt tensioner at least according to claim 1, characterized in that the radially inwardly bent end ( 16 ) of the band spring ( 15 ) with respect to the axis of rotation ( 5 ) of the pivot bearing ( 3 ) is arranged circumferentially such that through the bent end ( 16 ) of the band spring ( 15 ) formed stop surface normal to the resulting reaction force (F _{Z_R} ) of the traction means on the tension roller ( 6 ) is aligned. Belt tensioner at least according to claim 4, characterized in that the middle of the lever-side spring end ( 13 ) to the middle storage level ( 21 ) of the pivot bearing ( 3 ) has such an axial distance (L ₂ ), that by the tangential spring force (F _{F_T} ) about the tilt axis ( 22 ) on the cocking lever ( 2 ) applied tilting moment M _K = F _{F_T} × L ₂ with opposite direction of rotation of the tilting moment M _K = F _{Z_R} × L _{1 of} the reaction force (F _{Z_R} ) of the traction means on the clamping lever ( 2 ), so that the moment equilibrium M _K = F _{Z_R} × L ₁ = F _{F_T} × L ₂ holds. Belt tensioner according to one of the preceding claims, characterized in that the diameter (D _FB ) of the spring band ( 15 ) smaller or larger than the diameter (D _F ) of the torsion spring ( 11 ). Belt tensioner according to claim 5 or 6, characterized in that for those of the spring band ( 15 ) generated radial force (F _FB ), for the on the damping sleeve ( 18 ) acting radial force (F _DH ), for the diameter (D _DH ) of the damping sleeve ( 18 ) and for the tension lever ( 2 ) adjoining forces the relationship F F_R = F F_T ± F FB - ΣF DH applies, where ΣF DH = (F F_R ± F FB ) × μ. Belt tensioner according to one of the preceding claims, characterized in that the pivot bearing ( 3 ) the bearing pin ( 7 ), the bearing hub ( 8th ) and one between the bearing pin ( 7 ) and the bearing hub ( 8th ) arranged plain bearing bush ( 9 ; 9 ' ), wherein the plain bearing bush ( 9 ; 9 ' ) consists of a plastic. Belt tensioner according to claim 8, characterized in that the plain bearing bush ( 9 . 9 ' ) consists of a plastic with an internal lubricant. Belt tensioner according to claim 9, characterized that the lubricant is replaced by PA46PTFE15 (high temperature polyamide + Polytetraflourethylen) or by a plastic with chemical bonded PTFE (polytetrafluoroethylene) with a proportion between 5% and 30% is formed. Belt tensioner according to one of the preceding claims, characterized in that on the plain bearing bush ( 9 ) a circumferential sealing lip ( 23 ) is injected. Belt tensioner according to one of the preceding claims, characterized in that the plain bearing bush ( 9 ' ) is slotted and radially outside a conical surface ( 25 ), on which the bearing hub ( 8th ) of the tensioning arm ( 2 ) with a radially inner conical lateral surface ( 26 ) is radially supported. Belt tensioner according to one of the preceding claims, characterized in that the bearing pin ( 7 ) integral with the aluminum housing ( 4 ) connected is. Belt tensioner according to one of the preceding claims, characterized in that the damping sleeve ( 18 ) in one piece to the band spring ( 15 ) is formed. Belt tensioner according to claim 14, characterized in that the damping sleeve ( 18 ) by injection or rolling integrally with the band spring ( 15 ) connected is.