WO2004015305A1

WO2004015305A1 - Tensioning device for a belt drive

Info

Publication number: WO2004015305A1
Application number: PCT/EP2003/008273
Authority: WO
Inventors: Gunnar Pralle; Bernd Hartmann
Original assignee: Ina-Schaeffler Kg
Priority date: 2002-08-02
Filing date: 2003-07-26
Publication date: 2004-02-19
Also published as: DE10235285A1; AU2003253337A1

Abstract

The invention relates to a tensioning device for a belt drive, comprising a device housing (5) for accommodating spring and damping elements with a tensioning arm (4) rotatably mounted thereon, in addition to a pressure element (3) that is located on the free end of the tensioning arm (4). To improve a tensioning device of this type, the damping element consists of a hollow cylindrical outer part (7, 10, 13) and a cylindrical inner part (8, 11, 14), between which rolling or sliding bodies (9, 12, 15) are arranged, and the inner face of the outer part (7, 10, 13), the outer face of the inner part (8, 11, 14) and/or the rolling or sliding bodies (9, 12, 15) are configured in such a way that on said parts or on the surfaces lying opposite said parts, a surface deformation of the components occurs in a macroscopically reversible elastic manner when said parts are exposed to a force (F1, F2) or displaced in relation to one another, said deformation increasing the rolling or sliding resistance of the rolling or sliding bodies (9, 12, 15). This increase in rolling or sliding resistance causes the damping of pivoting displacements of the tensioning arm (4).

Description

Tensioning device for a belt drive

description

Field of application of the invention

The invention relates to a tensioning device for a belt drive, with a device housing for receiving spring and damping means, with a tensioning arm rotatably mounted thereon and with a pressure means arranged at the free end of the tensioning arm.

Background of the inventor

To prevent a drive belt from slipping on the drive pulleys of a belt drive, the drive belt is generally deflected from its uninfluenced wrap path by means of a tensioning device acting on the belt between the drive pulleys, thus generating the necessary pretensioning force which presses the belt onto the drive pulleys. Such clamping devices consist essentially of a non-rotatably arranged housing on which a clamping arm for a Riemena press roller is pivotally mounted. A spring damping device is located in the housing, the spring being supported on the one hand on the housing and acting on the tension arm with its other end. The damping mechanism ensures that the belt vibrations occurring in such a drive system are limited to a tolerable level. According to the prior art, such a damping device usually consists of brake bodies, which are either attached to the housing. se or are attached to the tension arm and act with a certain contact force on an effective surface with respect to the rotational movement of the tension arm. Such belt tensioning devices are known, for example, from DE 34 19 969 A1 and DE 37 28 158 A1, in which annular rubber-elastic elements fulfill the braking or vibration damping function. The disadvantage of these damping devices is that they are subject to abrasive wear and in some cases, lubricants must also be used in order to achieve a desired damping effect.

In addition, CH 31 62 36 and CH 32 49 87 show rolling bearings which essentially consist of an outer part, an inner part and rubber-elastic rolling elements arranged in between. In the case of these roller bearings, the distance between the bearing parts which are movable relative to one another is smaller than the diameter of the roller bodies before they are inserted into the roller bearing, so that a radially acting prestress acts on the roller bodies used. Before being introduced into the space between the inner bearing part and the outer bearing part, the rolling elements have an approximately round cross section. Depending on the preload given to the rolling elements, due to molecular rearrangement within them, which, however, proceed without any further external change in shape, rotation of the two parts mentioned with respect to one another has a greater or lesser resistance. According to these publications, such bearings can also be used to a certain extent as a movement damper.

Object of the invention

Based on this prior art, the object of the invention is to further develop a belt tensioning device according to DE 34 19 969 A1 in such a way that more cost-effective production and better operating behavior can be achieved. Summary of the invention

This object is achieved from the features of the main claim, while advantageous refinements and developments of the invention can be found in the subclaims.

Accordingly, it is provided that the tensioning device for a belt drive is designed with a device housing for receiving spring and damping means, with a tensioning arm rotatably mounted thereon and with a pressure means arranged on the free end of the tensioning arm in such a way that the damping means consists of a there is a hollow cylindrical outer part and a cylindrical inner part, between which rolling or sliding bodies are arranged, with the inside of the outer part, the surface of the inner part and / or the rolling or sliding bodies being formed in such a way that on or on them of the surface opposite these components when a force is applied to them and when they move relative to one another, a macroscopic surface deformation of the components that increases and dampens the rolling or sliding resistance of the rolling or sliding bodies is produced. The outer part can be designed as an outer housing part and the inner part as an inner housing part.

It can also be provided that one or both of the opposite sides of the outer part and the inner part of the damping device are visually elastic or automatically designed to be reversibly flexible and the rolling or sliding bodies are made of a metallic material. With a relative movement of the inner part and outer part to each other and when the rolling elements are subjected to a contact pressure, these rolling elements can penetrate into this elastic layer and constantly perform deformation work along their runway, which has a damping effect on the movement of the tensioning arm. This deformation behavior is achieved, for example, by the fact that the outer part and / or the inner part of the damping device have surfaces that face one another and that consist of an elastomer or another, preferably a polymer material, that permit reversible deformation of the surfaces. In contrast, it can be provided in another embodiment of the invention that the inner part and the outer part have rigid surfaces and the rolling bodies consist of an elastomer or another elastic material. This ensures that these rolling elements are deformed in macroscopic dimensions when subjected to a preload or normal force such that when the outer part or the inner part moves relative to one another, the deformation work has a damping effect on the mobility of the clamping arm of the clamping device. In this damping device, elastically non-deformable rolling elements are also arranged between the inside of the outer part and the surface of the inner part, which serve as spacers for the elastically deformable rolling elements. The diameter of the elastically deformable rolling elements is larger than the diameter of the elastically non-deformable rolling elements.

In a further variant of the invention, the inside of the outer part, the surface of the inner part and / or the surface of the rolling or sliding bodies consists of a flexible or elastic material layer which includes a viscous material, the rolling bodies in turn consisting of a material which is not independently reversibly deformable.

Another variant of the design principle according to the invention provides that the inside of the outer part or the surface of the inner part has a rigid surface with sliding bodies formed thereon, while the opposite surface has a comparatively soft surface made of a material with automatically reversible elastic deformation behavior.

Finally, it can be provided that the damping device is a component of the pivot bearing for the tensioning arm and is preferably designed as a tapered roller, inclined ball or deep groove ball bearing, wherein the rolling or sliding bodies can have a spherical, cylindrical, conical or needle-shaped geometry.

Ultimately, it is considered sensible if the pressure means of the tensioning device is designed as a roller or sliding shoe. Brief description of the drawings

The invention can be explained on the basis of exemplary embodiments which are illustrated in the accompanying drawing. In it show:

FIG. 1 shows a schematic illustration of a belt tensioning device,

FIG. 2 shows a schematic cross-sectional illustration of the damping device of the belt tensioning device,

Figure 3 shows another variant of the damping device and

Figure A is a damping device without rolling elements.

Detailed description of the drawings

The illustration according to FIG. 1 shows a schematic side view of a belt tensioning device 1 with which a drive belt 2 is deflected into a pretensioned position. The belt tensioning device 1 essentially consists of a housing 5 which is fastened in a rotationally fixed manner to a component 16 of a drive device by means of a connecting piece 6. At the free end of this connector 6, an inner part 8 of the housing 5 is fixed non-rotatably, which is coaxially surrounded by a housing outer part 7. Rolling elements 9 are inserted between these two housing parts 7, 8, so that the outer housing part 7 and the inner housing part 8 can be rotated relative to one another.

With the housing outer part 7 a S arm 4 is connected, which carries a pressure roller 3 for the drive belt 2 at its free end. The tensioning arm 4 is pressed together with the pressure roller 3 by a spring (not shown separately) with a force F against the drive belt 2, so that the latter is accordingly pre-tensioned.

The belt tensioning device 1 also has a damping mechanism, which ensures that the tensioning arm 4 lies quietly on the drive belt 2 and is not excited ^to torsional vibrations due to belt vibrations.

As can be seen in FIG. 2, the embodiment of the damping device according to the invention shown there, deviating from the previously customary damping systems, consists of macroscopically non-deformable rolling elements 9 which are arranged between the macroscopically automatically reversibly deformable surfaces 18, 19 of the outer part 7 and the inner part 8 of the housing 5 , These deformable surfaces 18, 19 can be formed from an elastomer layer or another suitable polymer material layer, which are formed on the inside of the housing outer part 7 and / or on the outside of the inner part 8.

The rolling elements 9 arranged between the housing inner part 8 and the housing outer part 7 cause an elastic deformation of the surfaces 18, 19 of the housing outer part 7 and the housing inner part 8 when these parts 7, 8 are acted upon by a force F1, F2 9 as a result of the relative movement of these two parts 7, 8 from one another. The deformation energy used is expressed in the rolling elements 9 in an increased rolling resistance compared to non-deformable rolling surfaces, which is used as a damping effect for the belt tensioning system. The force F1, F2 acting on the rolling elements 9 is preferably generated by an axial spring acting axially on the outer housing part 7 or the inner housing part 8, which is not shown separately here.

In another embodiment of the invention it can be provided that at least one of the mutually facing surfaces of the housing outer part 7 and / or the housing inner part 8 consist of a flexible plastic film. This flexible plastic film encloses itself between the metallic part of the housing and / or housing adjoining part 7, 8 a viscoelastic liquid which ensures the desired elastic deformation of the plastic film which has a damping effect on the rotary movement of the tensioning arm 4 when the rolling elements 9 roll past , The rolling elements 9 themselves can be designed as steel balls and can be components of the rolling bearing with which the pivoting of the tensioning arm 4 is achieved. This ball bearing can be designed as a tapered roller bearing, an inclined ball bearing or also as a deep groove ball bearing, wherein the rolling elements 9 can have a spherical, a cylindrical, a conical or a needle-shaped geometry. This integration of the damping device in the ball bearing for the tensioning arm 4 allows a particularly compact and inexpensive manufacture of the belt tensioning device according to the invention.

In the variant of the belt tensioning device according to the invention shown in FIG. 3, the inside of the outer housing part 10 and the outside of the inner housing part 11 have a hard and macroscopically non-deformable surface. Rolling elements 1 are arranged between these housing parts, which are not elastically deformable and determine the distance between the inside of the housing outer part 10 and the surface of the housing inner part 11 under the action of a force F1, F2. In addition, rolling elements 12 are arranged in this intermediate space, which are reversibly elastically deformable, so that deformation work must be performed when they roll off.

As can be clearly seen in FIG. 3, the distance between the inside of the outer housing part 10 and the surface of the inner housing part 11 is selected such that it is smaller than the diameter of an elastically not deformed and initially approximately circular rolling element 12. These rolling elements 12 can be made from an elastomer or another self-reversibly deforming polymer material. In addition, it can be provided that the rolling elements 12 consist of a spherical plastic film which includes a viscoelastic liquid 16.

The elastically non-deformable rolling elements 17 fulfill, in addition to their usual bearing tasks in a rolling bearing, also the function of spacers for the elastic rolling elements 12 which are larger in diameter, so that this damping-acting bearing for the tensioning arm 4 of a belt tensioning device 1 also possibly without an axial force can be produced on the spring generating elastic rolling elements 12. This embodiment of the invention acts solely by the form-fitting assembly of the two housing parts 7, 8 with the interposition of the elastically non-deformable rolling elements 17 on the elastically deformable rolling elements 12, a normal force F1, F2, which in the static state causes the rolling elements 12 to flatten and with a relative movement of the outer housing part 10 and the inner housing part 11 to each other caused a circumferential deformation of the elastic rolling elements 12. In this way, a rolling resistance is generated, as a result of which a damping effect on the deflection movement of the tensioning arm 4 of the belt tensioning device 1 is brought about.

FIG. 4, on the other hand, shows another embodiment of the design principle according to the invention, in which the damping device manages without V-shaped bodies between the inside of the outer housing part 13 and the surface of the inner housing part 14. For this purpose, rigid sliding bodies 15 are formed on the inside of the outer housing part 13, the ends of which slide radially inward and are pressed into the elastically reversibly deformable material 20 of the inner housing part 14. In the event of a relative movement of these two housing parts 13, 14 to one another, indicated by the horizontal arrow, and the action of a force F1, F2 on at least one of these housing parts, the sliding bodies 15 cause the elastic material 20 of the housing interior 14 to deform, which automatically reversibly reforms, when the respective sliding body 15 moves away from this location. The necessary deformation work causes the described damping behavior with regard to the mobility of the clamping arm 4. In this damping device, a lubricant must be used in individual cases between the surfaces that come into contact, with the aid of which adhesive forces between the sliding bodies 15 and the inner surface 20 can be reduced , Reference numbers list

1 belt tensioner

drive belts

3 pressure means

clamping arm

casing

connector

7 outer part

8 inner part

9 rolling elements

10 outer part

11 inner part

12 rolling elements

13 outer part

14 inner part

15 sliding bodies

16 Viscous material

17 Non-elastic rolling elements

18 Reversible elastic material

19 Reversible elastic material

20 reversible elastic material

F1 force

F2 force

Claims

claims

1. Tensioning device for a belt drive, with a device housing (5) for receiving spring and damping means, with a tensioning arm (4) rotatably mounted thereon and with a pressing means (3) arranged on the free end of the tensioning arm (4), characterized that the damping means consists of a hollow cylindrical outer part (7, 10, 13) and a cylindrical inner part (8, 11, 14), between which rolling or sliding bodies (9, 12, 15) are arranged, and that the inside of the outer part ( 7, 10, 13), the surface of the inner part (8, 11, 14) and / or the rolling or sliding bodies (9, 12, 15) are formed in such a way that on or on the surface opposite these components the application of a force (F1, F2) and when moving relative to each other occurs a rolling or sliding resistance of the rolling or sliding body (9, 12, 15) increasing macroscopic surface deformation.

2. Tensioning device for a belt drive according to claim 1, characterized in that the side (18) of the outer part (77) and / or the side (1S, 20) that comes into contact with the rolling or sliding bodies (9, 12, 15) of the inner part (8, 14) have an automatically reversible elastic deformation behavior.

3. tensioning device for a belt drive nacri claim 2, characterized in that the outer part (7) and the inner part (8, 14) facing surfaces (18, 19, 20) made of an elastomer or of another automatically reversibly elastic material, preferably a polymer material.

4. Clamping device for a belt drive according to claim 1, characterized in that the rolling bodies (12) made of an elastomer or egg nem other automatically reversible elastic material, preferably a polymer material.

5., tensioning device for a belt drive according to claim 4, characterized in that elastically non-deformable rolling elements (17) are arranged between the elastically non-deformable inside of the housing outer part (10) and the elastically non-deformable surface of the housing inner part (11).

6. Clamping device for a belt drive according to claim 4 and 5, characterized in that the diameter of the elastically deformable rolling elements (12) is larger than the diameter of the elastically non-deformable rolling elements (17).

7. tensioning device for a belt drive according to at least one of claims 1 to 3, characterized in that the inside of the outer part (7, 10, 13), the surface of the inner part (8, 11, 14) and / or the surface of the roller - Or sliding body (9, 12, 15) consists of a flexible material layer, which includes a viscous material (16).

8. Tensioning device for a belt drive according to at least one of the preceding claims, characterized in that the rolling or sliding bodies (9, 15, 17) consist of a metallic material.

9. Clamping device for a belt drive according to at least one of the preceding claims, characterized in that the damping means are components of a rolling bearing, preferably a tapered roller, angular ball or deep groove ball bearing in particular for mounting the tensioning arm (4).

10. Clamping device for a belt drive according to claim 8, characterized in that the rolling or sliding bodies (9, 12, 15, 17) have a spherical, cylindrical, conical or needle-shaped geometry.

11. Clamping device for a belt drive according to at least one of the preceding claims, characterized in that the inside of the outer part (13) or the surface of the inner part (14) has a rigid surface with sliding bodies (15) formed thereon, while the opposite surface a material (20) with viscoelastic or automatically reversible elastic deformation behavior exists.

12. Tensioning device for a belt drive according to at least one of the preceding claims, characterized in that the pressing means (3) is designed as a roller or sliding shoe.