WO2008107249A1

WO2008107249A1 - Clamping device for a traction mechanism drive

Info

Publication number: WO2008107249A1
Application number: PCT/EP2008/051313
Authority: WO
Inventors: Johann Singer; Christoph Broese; Bernhard RÖLL; Lajos Farkas
Original assignee: Schaeffler Kg
Priority date: 2007-03-06
Filing date: 2008-02-04
Publication date: 2008-09-12
Also published as: DE102007010713A1

Abstract

The problem addressed by the invention, that of creating a simple and cost-effective clamping device for a traction mechanism drive, which, while ensuring more reliable operation with regard to known technical solutions, requires a lower manufacturing cost in particular and a simplified installation of the tensioning pulley (8) at the swiveling arm (6), is substantially solved by the fact that, while a conventionally provided centering pin is avoided, the inner bearing ring (11) of the roller bearing (7) of the tensioning pulley (8) is supported axially on a first base surface (10) constructed to be flat, by the fact that the radial support of the tensioning pulley (8) is implemented exclusively by means of a fastening screw (12) passing through the roller bearing (7) in the axial direction, and by the fact that the tensioning pulley (8) has at least one axially aligned ring-shaped or partially ring-shaped flange (18) which penetrates into a corresponding annular groove (17) of a stepped second, radially outer and largely flat base surface (16) in such a manner that unhindered rotation of the tensioning pulley (8) is possible during the operation of the clamping device.

Description

Name of the invention

Clamping device for a traction mechanism drive

Field of the invention

The invention relates to a tensioning device for a traction mechanism drive according to the features of patent claim 1.

Background of the invention

Clamping devices for traction drives, such as belt or chain drives, are for quite some time in a variety of embodiments, for example from DE 43 45 150 A1, DE 698 05 018 T2, DE 102 25 617 A1, DE 102 48 352 A1, the DE 10 2004 025 739 A1 and DE 10 2005 029 789 A1.

Essentially, these clamping devices consist of a stationary base part, with a pivotally mounted at one end and spring-loaded swivel arm of different lengths. At the other end, the swivel arm carries at least one tensioning roller, which is mounted rotatably predominantly by means of a roller bearing.

A functionally relevant requirement of such tensioning devices is the maintenance of Zugmittelführung. The squareness of the housing to the swivel arm, a precisely fitting radial and axial Schwenkarmlagerung and low wear rates of the bearing components ensure the function of Zugmittelführung, in particular a belt guide.

The pivot arms are preferably formed as a die-cast, and for example made of die-cast aluminum. However, even under optimum production conditions, in particular tensioners with die-cast pivot arms can be used for so-called te "Long-arm clamping devices" with 70 mm to 120 mm swing arm length Add up component tolerances to a maximum of 1.5 ° squareness deviation, which requires machining of the relevant connection surfaces of the components to be joined together.

Thus, the belt tensioning device according to DE 43 45 150 A1 has a pivot arm with a roller-side plan base on which the bearing inner ring of the roller bearing of the tensioning roller is axially supported. For fixing the tension roller on the pivot arm, a screw is provided which passes through the pot-shaped bearing inner ring axially, supported by means of the screw head at the bottom of the cup-shaped bearing inner ring and engages in a corresponding threaded bore of the pivot arm. Although may be realized with such a fixture, the rectangularity of the system, however, the exact centering of the bearing inner ring or the tensioning roller with respect to the pivot arm or its threaded bore is not always guaranteed lack of centering, which in turn may result in functional disadvantages of the clamping device.

To address this problem, it has largely prevailed in the art to thread the idler during assembly with its bearing inner ring on a centering of the pivot arm, whereby an exact radial support of the bearing inner ring of the tensioner and a simplified assembly are given the same. The bearing screw penetrating the bearing inner ring, which may optionally have a step for radial connection to the inner contour of the bearing inner ring, essentially serves exclusively to fix the tensioning roller on the pivoting arm (see the documents DE 698 05 018 T2, DE 102 25 617 A1 DE 102 48 352 A1, DE 10 2004 025 739 A1 and DE 10 2005 029 789 A1).

The well-known technical solutions in the latter documents, however, have the common feature that they require a considerable manufacturing effort, since the machining of the connection surface of the pivot arm for receiving the tension roller together with rolling bearing by "roundabout lead "of the tool (in particular end mill) to the said centering pin is comparatively expensive.

Object of the invention

The invention has for its object to provide a simple and cost-effective clamping device for a traction mechanism, which in particular requires a reduced manufacturing effort while ensuring safe operation in view of the prior art. Furthermore, a simpler installation of the tension roller to the swivel arm is to be achieved.

Summary of the invention

The invention is based on the finding that despite dispensing with a favored by experts, but consuming to produce centering pin for centering the tensioner on the swing arm still safe and quality-appropriate fixing the tensioner on the swing arm is possible if further measures are provided, in particular the exact Concentrate the tensioning roller with respect to the swivel arm.

According to the features of the main claim, the stated object is achieved by a tensioning device for a traction drive, with one on a stationary base end rotatably mounted and spring-loaded pivot arm, the other end carries a rotatably mounted by means of at least one roller bearing tension roller, the pivot arm while avoiding a conventional provided centering pin has a relation to the axis of rotation of the tensioning roller radially inner and planar formed first base surface, the surface largely corresponds to the surface of the bearing inner ring of the rolling bearing spanned plane, wherein the bearing inner ring of at least one rolling bearing axially supported on this first base, wherein the Radial support of the tension roller realized exclusively by means of a rolling bearing in the axial direction passing through fastening screw is, which in turn engages in a threaded bore of the pivot arm penetrating the first base surface, wherein the tension roller has at least one axially aligned annular or partially annular flange, which in the mounted state of the tensioning roller on the pivoting arm in a corresponding annular groove of a radially outer and the first base area stepped second, largely plan base has penetrated, that during assembly, although a pre-positioning and securing the tension roller against slipping in relation to the pivot arm is ensured, however, an unhindered rotation of the tension roller is possible during operation of the tensioning device.

The subclaims describe preferred developments or refinements of the invention.

Thereafter, in a further embodiment of the invention according to a first possible embodiment, that the fastening screw has at least one penetrating into the bore of the bearing inner ring and radially to the inner contour of the bearing inner ring snug centering for exact centering of the tension roller on the pivot arm. The at least one centering step of the fastening screw can be cylindrical as well as conical.

In contrast, according to a further possible embodiment for exact centering of the tensioning roller with respect to the pivoting arm, one or more suitable contours and / or attachments, such as splash guard protections, etc., may be provided on the tensioning roller and / or the pivoting arm.

As the invention finally still provides, at least the pivot arm is formed as a metal die-cast part and the first base surface for axial support of the bearing inner ring of the at least one roller bearing machined by milling or planing means a Walzenframes or the like, which in view of the conventional processing one with one cent rierzapfen provided connection surface by means of a finger milling cutter faster and cheaper to accomplish.

Brief description of the drawings

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

1 shows an inventively designed clamping device without tensioning roller in a sectional view, and

2 shows the swivel arm of the clamping device according to FIG. 1 with a clamping roller which can be laid on it in an exploded view.

Detailed description of the drawings

The tensioning device shown in FIG. 1 for a traction mechanism, not shown, which may be a belt or chain drive, initially comprises a base part 1, the same via a contact surface 2 thereof by at least one not shown here, but known per se, an axial bore 3 of the base part 1 penetrating mechanical fastener, such as a fastening screw, fixed to a supporting member, also not shown in detail, for example, on a crankcase of an internal combustion engine of a motor vehicle, can be fastened.

The base part 1 is preferably formed as a metal die-cast part. Centrally within the base part 1 a said axial bore 3 having bearing receptacle 4 is arranged, on which via a slide bearing 5, a pivot arm 6 is rotatably mounted.

The swivel arm 6 can be equipped at its free end with a tensioning roller 8, known per se and rotatably mounted by means of at least one roller bearing 7 (FIG. 2). The tensioning roller 8 is in turn adjustable against the traction mechanism drive by means of a torsionally concentric surrounding the bearing support 4 spring 9, which is supported at one end on the base part 1 and the other end on the pivot arm 6, the pivot arm 6 is biased to the base part 1 and is prestressed. The pivot arm 6 is also formed as a metal die-cast part, for example as an aluminum die-cast part.

As shown in FIG. 2 it can be seen further, the pivot arm 6, in contrast to the favored by the art construction over a with respect to the axis of rotation of the tension roller 8 radially inner and planar formed first base 10, on soften the bearing inner ring 11 of the bearing 7 of the tension roller 8 is axially supported. This first base 10 is formed such that on the same exclusively the bearing inner ring 11 is axially supported. In essence, the surface area of the first base surface 10 is selected so that it largely corresponds to the surface area of the spanned by the bearing inner ring 11 of the rolling bearing 7 level. As can be seen, the first base surface 10 is formed axially raised and adapted in diameter to the outer diameter of the bearing inner ring 11.

The radial support of the tension roller 8 is accomplished by means of a rolling bearing 7 in the axial direction passing through fastening screw 12, which in turn engages in a first base 10 centrally penetrating threaded bore 13 of the pivot arm 6. In the present case, the fastening screw 12 has a screw bolt 12a with a smaller diameter compared to the inner diameter of the bearing inner ring 11, but it has a centering step 15 penetrating into the bore 14 of the bearing inner ring 11 and fitting radially to the inner contour of the bearing inner ring 11 an exact centering of the tension roller 8 is ensured on the pivot arm 6.

By this constructive construction, a simple centering and fixing of the rolling bearing 6 together with connected tensioning roller 8 is accomplished, the axial support of the tensioning roller 8 alone on the flat first base 10 of the pivot arm 6 and the radial support waiving a conventional one-piece on the Swivel arm designed centering tap exclusively by the said fastening screw 12 takes place. Slippage of the tension roller 8 with respect to the pivot arm 6 both during assembly and during operation of the tensioner is effectively avoided.

The embodiment preferably shows only one centering stage 15, which is considered sufficient. Of course, it is also possible to dispense with centering steps 15 entirely and to design the bolts 12a in such a way that they conform to the inner contour of the bearing inner ring 11 over substantially the entire length or screwed into the bearing inner ring (not shown in detail).

As shown in FIG. 2 further shows, the centering 15 is cylindrical. Appraised as appropriate and accordingly detected by the invention with but also not shown conical outer surface of the centering 15, as this allows a further simplified assembly and centering.

The above embodiment is based on a centering exclusively by means of the fastening screw 12, which in turn preferably has at least one centering stage 15. However, it is also possible and is accordingly also covered by the invention, for centering the tension roller 8 with respect to the same supporting pivot arm 6 one or more suitable contours, which can be easily and inexpensively produced in the course of the actual casting process, and / or Attachments, such as protections against spray and / or the like, to provide the tension roller 8 and / or the pivot arm 6.

As already mentioned in the introduction, pivoting arms require 6 for so-called "long-arm tensioners" increased manufacturing costs by a machining of the pads, here in the speech standing first base 10 to ensure the required perpendicularity of the jig. This machining operation is conventionally costly and time-consuming, for example by means of a milling cutter, by "bringing it" around the centering pin favored by the experts, as already explained above, due to the fact that such a centering pin is not provided in the device according to the invention , the machining of the first base 10 can be carried out much cheaper by milling / planning by means of a Walzenfrirners or the like.

Notwithstanding the fact that a sufficient determination of the tension roller 8 is ensured on the pivot arm 6 by the inventive design of the tensioning device, according to Figures 1 and 2 to further facilitate the assembly of the tension roller 8, a second, largely planar base 16 is provided on the pivot arm 6, which adjoins the first base surface 10 radially outward, but is stepped down to the same axially downwards.

This second base 10 has an annular groove 17 which can be produced simply and inexpensively during the actual casting process. In this annular groove 17 penetrates during assembly an axially aligned annular or semi-annular flange 18 of the tension roller 8, in such a way that during assembly, although a pre-positioning and extensive securing of the tension roller 8 is ensured against slipping, but during operation of the clamping device an unobstructed rotation of the tension roller 8 is possible.

A subsequent machining of the second base surface 16 together with the annular groove 17 is not required because they serve only the pre-positioning and securing the tension roller in the assembly process. reference numeral

1 base part

2 contact surface 3 axial bore

4 bearing support

5 plain bearing

6 swivel arm

7 Rolling bearings 8 Tensioning roller

9 torsion spring

10 first floor space

11 bearing inner ring of the rolling bearing

12 fixing screw 12a screw bolt

13 threaded hole on the swing arm 6th

14 hole in the bearing inner ring 11th

15 centering stage

16 second base 17 annular groove

18 flange on the tension roller 8

Claims

claims

1. Clamping device for a Zugmitteltheb, with one on a stationary base (1) rotatably mounted at one end and spring-loaded pivot arm (6), the other end by means of at least one roller bearing (7) rotatably mounted tension roller (8), wherein the pivot arm (6) below Avoiding a conventionally provided centering pin has a with respect to the axis of rotation of the tension roller (8) radially inner and planar formed first base surface (10) whose area content largely corresponds to the surface of the bearing inner ring (11) of the rolling bearing (7) spanned plane wherein the bearing inner ring (11) of the at least one rolling bearing (7) is axially supported on this first base surface (10), the radial support of the tensioning roller (8) exclusively by means of a fastening screw (12) passing through the rolling bearing (7) in the axial direction ) is accomplished, which in turn in a first base surface (10) penetrating threaded bore (13) of the pivoting arm (6) engages, wherein the tensioning roller (8) has at least one axially aligned annular or partially annular flange (18), which in the assembled state of the tensioning roller (8) on the pivot arm (6) in such a corresponding annular groove ( 17) of a radially outer and the first base surface (10) graduated second, largely plan base (16) has penetrated, that during assembly, although a pre-positioning and securing the tension roller (8) against slipping in relation to the pivot arm (6) is guaranteed, however, an unhindered rotation of the tension roller (8) is possible during operation of the clamping device.

2. Clamping device according to claim 1, characterized in that the fastening screw (12) at least one in the bore (14) of the bearing inner ring (11) penetrating and radially to the inner contour of

Having bearing inner ring (11) fitting centering step (15) for exact centering of the tensioning roller (8) on the pivot arm (6).

3. Clamping device according to claim 2, characterized in that the at least one centering step (15) of the fastening screw (12) is cylindrical or conical.

4. Clamping device according to claim 1, characterized in that for centering the tensioning roller (8) with respect to the pivot arm (6) one or more suitable contours and / or attachments, such as protection against spray water and / or the like, on the tension roller (8 ) and / or the pivot arm (6) are provided.

5. Clamping device according to at least one of claims 1 to 4, characterized in that the pivot arm (6) is formed as a metal-cast part, and that the first base surface (10) for axially supporting the bearing inner ring (11) of the at least a rolling bearing (7) is machined by milling or planing by means of a roll end mill.