GB2329228A

GB2329228A - Tensioning device for drive belts

Info

Publication number: GB2329228A
Application number: GB9811011A
Authority: GB
Inventors: Manfred Brandenstein; Friedrich Wolfgang; Roland Haas; Roland Harich; Gerhard Herrmann; Josef Stork
Original assignee: SKF GmbH
Current assignee: SKF GmbH
Priority date: 1997-07-12
Filing date: 1998-05-21
Publication date: 1999-03-17
Anticipated expiration: 2018-05-21
Also published as: GB2329228B; DE19729994A1; GB9811011D0; FR2765940A1

Abstract

In a drive belt tensioning device there is provided a spring module 4 which can be readily flange-mounted and which is connected to a support member 1 and to a pivot member 2 in a manner precluding relative rotation. The spring module 4 comprises two cup-shaped housing parts 5,6 which form an annular chamber, in which the tensioning spring 7 is inserted, and the ends 12 of which spring are fastened to the housing parts 5,6. The parts 5,6 can rotate relative to one another to a limited extent and are secured via retaining projections 14,15.

Description

1 p 1 TENSIONING DEVICE FOR DRIVE BELTS 2329228 The invention relates to a

tensioning device for drive belts.

DE 42 09 914 A1 discloses a tensioning device which has a tensioning spring disposed axially adjacent to the tensioning pulley. The rolling bearing of the tensioning pulley is shrunk on a pivot member which is pivotably mounted on the journal of a support member via a plain bearing mounted eccentrically relative to the axis of rotation of the tensioning pulley. A suitably formed flange extension of the pivot member forms an annular housing for the tensioning spring together with the support member, in particular with its mounting plate.

The tensioning spring is thus a fixed component part of the tensioning device and always has to be tensioned and installed during assembly. This individual assembly prevents economical production of the spring feature in the housing, although the same spring is used for many installationdependent structural modifications.

On the other hand, in the event of altered requirements in respect of the tensioning forces, it is not simple to achieve this solely by changing the tensioning spring, since usually the fastening of the spring ends also has to be altered.

It is an object of the invention to devise a tensioning device which can be produced in a modular construction, and which can be adapted to various applications by combining function elements and which enables simple assembly to be performed.

This object is achieved in that the tensioning spring is incorporated in a two-part modular housing, wherein fastening elements for one spring end are provided on one housing part. On the other housing 2 is part are provided fastening elements for the other spring end and connecting elements for the nonrotational connection with the pivot member.

As a result of the modular construction there is a separation between the function of the tensioning spring and the eccentric movement of the pivot member on the support member.

The module can be produced and assembled separately, the tensioning spring being installed under tension. After assembly, the housing parts and the tensioning spring are secured against rotation in the "relaxed" direction and allow the required pivot range in the -tensioning" direction. The flangemounting on the pivot member and the load-bearing fastening elements is effected by connecting elements.

As a result of the way in which this object is achieved by the invention it is possible for modules of different tensioning force, pivot angle, diameter, etc., to be combined as desired with a variety of tensioning devices using the same connecting elements.

The separate production of the modules makes favourably priced calculations in respect of series production or with sub-contractors possible.

The invention will be described below with reference to the example of an embodiment illustrated in the drawings, wherein:

Figure 1 shows a longitudinal section through a tensioning device with a flangemounted spring module, and Figure 2 shows a side view of the tensioning device according to Figure 1.

The tensioning device illustrated in the drawings substantially comprises a support member 1, a pivot member 2 mounted thereon and a tensioning pulley 3 3 is arranged eccentrically thereon. These components are indicated by dashed lines.

A spring module 4 is also flange mounted which, being an essential part of the invention, is illustrated normally. It comprises two substantially cup-shaped housing parts 5,6 of sheet material, which enclose a tensioning spring 7. The axially inner housing part 6 is located on a shoulder 8 of the pivot member 2 and, by means of a radial projection 9, is connected thereto in a manner precluding relative rotation. The axially outer housing part 5 is located on the mounting flange 10 of the support member 1 and is also connected by a radial projection 11 in a manner precluding relative rotation.

The radially bent ends 12 of the tensioning spring 7 are each fastened via bores 13 to the housing parts 5,6 in a form-locking manner.

Three circumferentially spaced retaining projections 14 are formed on the periphery of the inner housing part 6, and can be snap-fitted in a position locking manner over a peripheral flange 15 on the outer housing part 5. On the outer housing part 5 there is formed an anchor plate 16 with a locating projection 17 so as to brace'the spring moment, for example against an engine block.

on the inner housing part 6 is formed a position indicator 18 which limits the pivotal movement and the spring deflection between two retaining projections 14 of the outer housing part 5. The pivot angle can be determined by the circumferential distance between these retaining projections 14, for example + 30 degrees.

During the assembly of the spring module 4 the spring ends 12 of the tensioning spring 7 are inserted into the housing parts 5,6 and are guided into the bores 13. Subsequently, by relative rotation of the 4 housing parts 5,6, the tensioning spring 7 is preloaded and by axial pressing together of the housing parts 5,6 the snap-fit connection is established via the peripheral retaining projections 14,15. The spring modules 4 can be stocked in this form.

The flange mounting on a prepared tensioning device 2,3 is effected in this example with the support member 1 removed, which is subsequently installed and secured.

Claims

CLAIMS:

1. A tensioning device for drive belts comprising a support member, a pivot member carrying the tensioning pulley and a tensioning spring disposed between them, in which the tensioning spring is contained in a twopart modular housing, wherein fastening elements for one spring end are provided on one housing part and on the other housing part are provided fastening elements for the other spring end and connecting elements for non-rotational connection with the pivot member.

2. A tensioning device according to Claim 1, in which at least one housing part is cup-shaped, wherein the circumference thereof has retaining projections which are secured axially with respect to one another and which, during installation, are arranged to allow relative rotation of the housing parts without obstruction.

is

3. A tensioning device according to Claim 1 or 2, in which limiting elements for a predetermined pivot range are provided on the housing parts.

4. A tensioning device according to any one of the preceding Claims, in which the tensioning spring is installed preloaded.

5. A tensioning device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

5. A tensioning device according to any one of the preceding Claims, in which the tensioning spring and the module housing form a separately produced, assembled unit which can be connected to the pivot member and the support member by snap-fitting.

6

6. A tensioning device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Amendments to the claims have been filed as follows CT.A T MR - 1. A tensioning device for drive belts comprising a support member, a pivot member carrying the tensioning pulley and a tensioning spring disposed between them, in which the tensioning spring is contained in a twopart modular housing, wherein fastening elements for one spring end are provided on one housing part and on the other housing part are provided fastening elements for the other spring end and connecting elements for non-rotational connection with the pivot member, in which at least one housing part is cup shaped, wherein is the circumference thereof has retaining projections which are secured axially with respect to one another and which, during instillation, are arranged to allow relative rotation of the housing parts without obstruction.

2. A tensioning device according to Claim 1, in which limiting elements for a predetermined pivot range are provided on the housing parts.

3. A tensioning device according-to any one of the preceding Claims, in which the tensioning spring is installed preloaded.

4. A tensioning device according to any one of the preceding Claims, in which the tensioning spring and the module housing form a separately produced, assembled unit which can be connected to the pivot member and the support member by snap-fitting.