DE102008028457A1 - Tensioning device i.e. short-arm tightener, for traction mechanism drive e.g. belt drive, in internal combustion engine, has tightener carrier prestressed at base part by spring elements so that carrier sums spring forces of elements - Google Patents

Abstract

The device has a tightener carrier (6) rotatably supported on a centrally arranged bearing journal (2) of a fixed base part (1) over a sliding bearing (4) by a hub-shaped bearing part (5). The carrier is prestressed at the base part by two spring elements (11, 12) such that the carrier sums operative spring forces of the spring elements. The spring elements concentrically surround the bearing part, and are arranged concentric to each other and supported at the base part at one end and at the carrier at another end. The elements are formed by screw and/or spiral-shaped torsion springs.

Description

Name of the invention

The The invention relates to a clamping device for a Traction drive according to the feature combination of Patent claim 1.

description

Background of the invention

Clamping devices for a traction drive have long been known in a variety of embodiments. So is out of the DE 37 16 571 C1 For example, a tensioning device for belt in the manner of a so-called long arm tensioner with a friction bushing and cooperating with this coil spring, also known as torsion springs, to achieve a cushioning and damping of vibrations and shocks small amplitudes known.

The DE 10 2005 046 068 A1 further describes a tensioning device for a traction means, such as a belt, with a tensioning roller for the traction means, for example, an engine block rotatably about an axis to be arranged clamping lever and with a arranged on the one hand on the engine block and on the other hand on the clamping lever clamping-damping element , preferably with hydraulic damping mechanism, as well as with one, optionally supporting the clamping-damping element acting, on the one hand positionally stable and on the other hand arranged on the clamping lever, the tensioning lever biasing spring element, which is formed by a torsion spring. The combination of the integrated in the clamping-damping element compression spring with the torsion spring an extremely large bias is to be achieved with simultaneous given linear damping.

Furthermore, from the DE 44 26 666 A1 a tensioning device in the manner of a so-called Kurzarmspanners known, with a base part and a tension roller carrier, which are arranged partially concentric with each other, wherein a these parts bracing, guided on a sleeve torsion spring is used. Between the sleeve and the inner diameter of the torsion spring an inwardly fitting to the torsion spring longitudinally slotted clamping bush is arranged to prevent adverse spring vibrations and resulting noise excitations.

Also by the DE 44 28 560 A1 is a Kurzarmspanner exposed with a tensioner having tension arm. On the clamping arm, a sleeve is integrally formed, which surrounds a pivot axis of a housing concentrically. In a limited by the sleeve and the pivot axis annulus a slide bearing ring is housed. A helical torsion spring is attached on the one hand to the clamping arm and on the other hand to the housing. The helical torsion spring is enclosed in a space which is delimited by the clamping arm and the housing, and peripherally by the pivot axis and the sleeve. A torsion bar arranged concentrically to the pivot axis is fastened on the one hand to the tensioning arm and on the other hand to a radial flange, a friction disk being arranged between the same and the housing. The friction disc is axially clamped due to the axial force component of the helical torsion spring.

From the DE 35 90 411 C2 Furthermore, a belt tensioning device in the manner of a long-arm tensioner with a friction damping device is known which, instead of a helical torsion spring, has a flat coil spring.

In contrast, is from the DE 20 2007 005 928 U1 a belt tensioner in the manner of a double eccentric tensioner with a so-called adjustment eccentric and a Federkraftbeaufschlagten working eccentric known, wherein the adjusting eccentric essentially serves to increase the Installationshubes and is part of a base plate device with a hollow pin designed as a journal, while the spring-loaded working eccentric of the compensation of tolerance -, wear and temperature-related changes in length of the traction device or belt is used and is supported by a plain bearing bushing on the hollow pin and carries a roller bearing roller bearing, which is intended to be brought into operative connection with the tension means to be braced. For applying force to the working eccentric, a torsion spring is provided which is arranged axially in a region of the belt tensioner facing the load-bearing component between the bearing of the running disk and the base plate device.

In the DE 100 84 444 T1 Finally, a belt tensioner is disclosed in the manner of a so-called simple eccentric tensions, in which dispenses with a separate adjustment eccentric. This tensioner has in addition to the known per se Schraubentorsionsfeder for bracing the traction means via a so-called anti-rebound mechanism, which is coupled to the working eccentric and a sudden rebound movement of the same, so a sudden, relatively large movement of the belt tensioner away from the belt tensioning direction should stop. This anti-rebound mechanism has a one-way wrap spring clutch and a self-adjusting clutch, wherein the wrap spring is disposed concentric with the helical torsion spring, which is made of a spring wire material. due to the rebounding movement of the working eccentric contracts around the clutch and thus the rebounding movement of the working eccentric stops by frictional engagement with the clutch.

Alles the aforementioned clamping devices is common, the same over a single spring element in the form of a helical or spiral Torsion spring for tensioning the traction means have, wherein the clamping moment exclusively by the interpretation of the respective selected spring element is determined and with regard to in particular helical torsion springs an increased axial Space is required to apply the necessary clamping torque to be able to.

Object of the invention

Of the Invention is based on the object, a clamping device of generic type to improve such that with small axial space within wide limits a finer vote the applied spring force or the applied clamping torque is permitted and the constructive freedom with regard to the interaction Storage of the oscillating tensioning roller carrier and the Friction mechanism is extended.

Summary of the invention

Solved The object is achieved according to the features of the main claim by a tensioning device for a traction drive, with a stationary base part and with a via a sliding bearing on a centrally arranged bearing journal of the base part by means of a hub-shaped bearing part rotatably mounted tension roller carrier with at least one tension roller, wherein the tension roller carrier by means of at least two parallel connected, largely concentric arranged to each other and the bearing part concentrically surrounding Spring elements, each one at the base and at the other end on Clamping roller carrier are supported, the base part so is biased that the acting spring forces of add at least two spring elements connected in parallel.

By This structure is on the one hand a significant reduction the required axial space for the clamping device to record, since the total clamping torque on the at least two split in parallel spring elements, so that the same, in particular with regard to helical torsion springs, in their axial Building length can be shorter. On the other hand can spring elements with different wire geometry, Wire size, dimension etc. and accordingly different Tensioning moment and torque gradients are combined in such a way that a finer tuning of the required applied clamping torque is allowed. Finally, due to the flat design and the enlarged diameter of the tensioning device as a result of concentrically arranged spring elements a improved balance of the clamping arm of the tensioning device to record.

The Most mechanical belt tensioners see a torsion spring in helical or spiral form to initiate the belt tensioning torque before, wherein the torsion spring functionally not infrequently axial Compressive or tensile forces are superimposed.

The usually made of round wire Schraubentorsionsfedern can differently executed so-called legs for introduction have the clamping forces. Opposite that also a so-called legless helical Use torsion spring.

a lot of Clamping devices is common that the forces of action of Spring elements in addition to the initiation of a belt tension and normal forces to provide a mechanical friction work and in particular by targeted arrangement of the spring coil ends for a Balancing and stabilization of the oscillating tensioning roller carrier to care. Ie. the spring element contributes to a quasi edge-free Stress of the mostly executed as sliding bearing Storage of the tension roller carrier at.

Typical embodiments of a balanced tensioning device can the writings DE 10 2006 014 942 A1 and EP 0780 597 A1 be removed.

The Subclaims describe preferred developments or Embodiments of the invention.

After that the stationary base part of the clamping device can be cup-shaped Have shape and thus between the inner contour of the wall of the cup-shaped base part and the hub-shaped bearing part of the tension roller carrier form an annular space in which arranged the at least two parallel spring elements are. The spring elements are advantageous as helical or spiral Torsion springs formed.

Advantageously, the annulus receiving the spring elements by means of one or more in the direction of the axis of rotation of the tension roller carrier extending annular and arranged on the base part and / or on the tension roller carrier Axialstege or Axialsteg sections corresponding to the selected number of spring elements in concentric be mutually arranged, each having a spring element receiving annular space areas to be divided. The annular Axialstege or Axialsteg sections can here largely fully or partially extend through the annulus.

Further It may be provided that at least one of the spring elements a mechanical damping device is assigned. The Damping device can by at least one for at least one spring element in series switched band spring element be formed, which with the base part or the tension roller carrier can be brought into contact and next to the elastic band spring a having friction lining coupled thereto.

The Clamping device according to the invention can both as known per se or short-arm tensioner, wherein the tension roller carrier a swing arm, in turn, the at least one tensioning roller as well as a known double or single eccentric clamp, its tension roller carrier by a tension roller bearing Work eccentric is formed, be trained.

Short description of the drawing

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

1 an axial section through an inventively designed clamping device according to a first preferred embodiment variant (section II 2 )

2 a sectional view taken along the section line II-II according to 1 , and

3 an axial section through the inventively designed clamping device according to a second preferred embodiment variant.

Detailed description the drawings

The 1 and 2 schematically show a clamping device in the manner of a so-called Kurzarmspanners for a traction mechanism, not shown, such as a belt or chain drive, with a on a supporting component or unit, such as a not shown housing of an internal combustion engine fixable and thus stationary base 1 ,

The base part 1 has a cup-shaped shape and has a centrally disposed bearing pin 2 with an axial bore 3 for receiving a likewise not shown in detail, known per se mechanical fastening element, such as a fastening screw. On the centrally arranged bearing journal 2 of the base part 1 is via a sliding bearing 4 in the form of a bearing bush by means of a hub-shaped bearing part 5 a tension roller carrier 6 rotatably mounted. It has a swivel arm 7 , which in turn at its free end at least one known tension roller 8th wearing.

Within the between the inner contour of the wall 9 of the cup-shaped base part 1 and the journal 2 the same and the hub-shaped bearing part 5 of the tension roller carrier 6 formed annulus 10 are at least two parallel, largely concentric with each other and the hub-shaped bearing part 5 likewise concentrically surrounding spring elements 11 . 12 arranged, which the tension roller carrier 6 to the base part 1 with a certain axial compressive force and a total torque bias by each spring element 11 . 12 at one end on the base part 1 and at the other end on the tension roller carrier 6 supported. This results in an addition of each spring element 11 . 12 on the tension roller carrier 6 acting spring forces recorded. Find here as spring elements 11 . 12 Torsional springs known per se use, optionally superimposed with an axial force.

As already stated above, with regard to the prior art, which predominantly uses torsion springs, a significant reduction in the required axial installation space for the clamping device can be recorded, since this is essentially dependent on the axial extent of the spring elements 11 . 12 or the torsion springs. Next can spring elements 11 . 12 are combined with different wire geometry, wire size, dimension, etc. and accordingly different clamping torque or torque rate such that a finer tuning of the required applied clamping torque, the bearing and the friction mechanism is allowed by adapting to current constraints, for example, a plurality of vorhalter spring elements 11 . 12 is selected with different spring force. Furthermore, due to the flat design and the increased diameter of the tensioning device due to the concentric spring elements 11 . 12 to note an improved balance or stabilization of the oscillating tensioning arm of the tensioning device. In addition, the system according to the invention has a positive effect on the Temperaturverältnisse. Last but not least, the security against breakage of the oscillatory spring elements can be adjusted.

However, the invention is not limited to the use of helical Torsionsfe But also recorded known per se, not shown here coil springs, which, where appropriate in combination with torsion springs, advantageous effect in the context of the invention and in particular small axial space allow fine tuning of the applied clamping torque and a better balance of the tensioning device.

As the 1 and 2 further show that is the two concentrically arranged spring elements 11 . 12 receiving annulus 10 by means of a in the direction of the axis of rotation 13 of the tension roller carrier 6 extending annular and present on the tension roller carrier 6 arranged, preferably integrally formed with the same axial web 14 in two annulus areas 15 and 16 split, in each of which a spring element 11 . 12 located. As a result, the spatial separation of the spring elements 11 . 12 secured to, for example, an undesirable, but possibly unavoidable fracture of a spring element 11 . 12 a hindrance of the still functional spring element 11 . 12 to avoid and thus to ensure the function of the clamping device still within limits.

In the present case is the axial web 14 designed such that this largely completely by the annulus 10 extends, so is a ring land.

Are more than two parallel and concentrically arranged spring elements 11 . 12 provided, it may of course be indicated, a corresponding number of annulus areas 15 . 16 by means of a plurality of concentrically arranged axial webs 14 form (not shown in detail).

The spring elements 11 . 12 or torsion springs are according to 1 in the present case, at least at one end, preferably at both ends, without legs, and with the at least one limb-free spring end they rest stump-like on a mechanical damping device 17 . 18 from, each of which is formed by a torsion spring connected in series band spring element. The radially outer spring element 11 or the torsion spring is supported with its lower end not shown in detail directly on the base part 1 and with its upper end on the damping device 17 on the tension roller carrier 6 from.

In contrast, the radially inner spring element is supported 12 or the torsion spring with its lower end on the base part 1 and on the damping device 18 over the axial bridge 14 of the tension roller carrier 6 from.

In essence, the two spring elements 11 and 12 , in the present case by the torsion springs, as a function of the oscillating movement and accordingly the pivoting direction of the tensioning roller carrier 6 a more or less force on the damping devices 17 . 18 or a clamping torque on the tension roller carrier 6 applied.

As a friction partner for the damping devices 17 and 18 act with respect to the radially outer spring element 11 the wall 9 of the cup-shaped base part 1 and with respect to the radially inner spring element 12 the adjacent inner circumferential surface 19 of the inner spring element 12 radially outside arranged axial web 14 of the tension roller carrier 6 ( 1 and 2 ).

The friction lining 18 consists for example of a suitable plastic, here polyamide with dry lubricant, eg. As PTFE, has proven to be practical.

This in 3 illustrated embodiment is different 1 only by a reverse arrangement of the two damping elements.

The above embodiments are based on a clamping device in the manner of a so-called Kurzarmspanners. In contrast, however, are also long-arm clamp and double and single eccentric according to the invention, ie with at least two parallel connected, largely concentric with each other arranged spring elements 11 . 12 can be formed and thus also covered by the invention (not shown).

1

base

2

pivot

3

axial bore

4

plain bearing

5

bearing part

6

Utility Carrier

7

swivel arm

8th

idler

9

Wall of base part 1 or tension roller carrier 6

10

annulus

11

spring element

12

spring element

13

axis of rotation

14

axial web

15

ring space area

16

Annulus area

17

damping device

18

damping device

19

Inner lateral surface at the axial web 14

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 3716571 C1 [0002]
• - DE 102005046068 A1 [0003]
• - DE 4426666 A1 [0004]
• - DE 4428560 A1 [0005]
• - DE 3590411 C2 [0006]
• - DE 202007005928 U1 [0007]
• - DE 10084444 T1 [0008]
• DE 102006014942 A1 [0016]
• - EP 0780597 A1 [0016]

Claims (9)

Clamping device for a traction mechanism drive, with a stationary base part ( 1 ) and with a via a sliding bearing ( 4 ) on a centrally arranged bearing journal ( 2 ) of the base part ( 1 ) by means of a hub-shaped bearing part ( 5 ) rotatably mounted tension roller carrier ( 6 ) with at least one tension roller ( 8th ), wherein the tension roller carrier ( 6 ) by means of at least two parallel connected, largely concentrically arranged to one another and the bearing part ( 5 ) concentrically surrounding spring elements ( 11 . 12 ), each one at the base part ( 1 ) and at the other end on the tension roller carrier ( 6 ), to the base part ( 1 ) is biased such that the acting spring forces of the at least two parallel spring elements ( 11 . 12 ) add. Clamping device according to claim 1, characterized in that the spring elements ( 11 . 12 ) are formed by helical and / or spiral torsion springs. Clamping device according to claim 1 or 2, characterized in that the stationary base part ( 1 ) has a pot-shaped shape and between the inner contour of the wall ( 9 ) of the cup-shaped base part ( 1 ) and the hub-shaped bearing part ( 5 ) of the tension roller carrier ( 6 ) a ring space ( 10 ) is formed, in which the at least two parallel spring elements ( 11 . 12 ) are arranged. Clamping device according to claim 1 or 2, characterized in that the movable tensioning roller carrier ( 6 ) has a pot-shaped shape and between the inner contour of the wall ( 9 ) and the hub-shaped bearing part ( 5 ) of an annulus ( 10 ) is formed, in which the at least two parallel spring elements ( 11 . 12 ) are arranged. Clamping device according to claim 3 or 4, characterized in that the spring elements ( 11 . 12 ) receiving annulus ( 10 ) by means of one or more in the direction of the axis of rotation ( 13 ) of the tension roller carrier ( 6 ) extending annular and the base part ( 1 ) and / or on the tension roller carrier ( 6 ) arranged axial webs ( 14 ) or axial web sections corresponding to the selected number of spring elements ( 11 . 12 ) in concentric with each other, each a spring element ( 11 . 12 ) receiving annulus areas ( 15 . 16 ) is divided. Clamping device according to claim 3 or 4, characterized in that the annular axial webs ( 14 ) or Axialsteg sections are largely full or partially through the annulus ( 10 ). Clamping device according to one of claims 1 to 6, characterized in that at least one of the spring elements ( 11 . 12 ) a mechanical damping device ( 17 . 18 ) assigned. Clamping device according to one of claims 1 to 7, characterized in that it is designed as a per se known long or Kurzarmspan ner, wherein the tension roller carrier ( 6 ) a swivel arm ( 7 ), which in turn has the at least one tensioning roller ( 8th ) wearing. Clamping device according to one of claims 1 to 7, characterized in that it is designed as a per se known double or single eccentric, wherein the tension roller carrier ( 6 ) by a tension roller ( 8th ) supporting working eccentric is formed.