EP2083956B1 - Method for the production of a one-piece metallic multiple whee and multiple wheel - Google Patents

Abstract

The invention relates to a method for the production of a one-piece metallic multiple wheel (2) for a traction mechanism, having at least two single wheels (3, 4) disposed next to each other, each having a wheel body (5, 6) with an exterior circumference (7, 8), wherein teeth (9, 10) are distributed across the outer circumference (7, 8) for engaging the traction mechanism, and wherein at least one of the at least two single wheels (3, 4) is configured as a chain, gear, or toothed belt wheel. The chain, gear, or toothed belt wheel is produced having a rough contour, wherein the tooth thickness of the rough contour - in an axial view - is larger than the tooth thickness of the final contour of the finished chain, gear, or toothed belt wheel, and this rough contour is then reformed by means of non-machining reforming, particularly by means of rolling, into the finished tooth contour as a function of the traction mechanism used, wherein a toothed belt wheel contour is produced from a chain wheel, or gear wheel contour, or a chain wheel contour is produced from a gear wheel or toothed belt wheel contour, or a gear wheel contour is produced from a toothed belt wheel or a chain wheel. The invention further relates to a preform for the production of a multiple wheel, and to a multiple wheel.

Description

The invention relates to a method for producing a one-piece, metallic multi-wheel for a traction mechanism drive according to the preamble of claim 1, as well as an integral, metallic Mehrfachrad according to the preamble of claim 5 (see, respectively WO-A-01/74514 ).

Multiple sprockets are already known from the prior art. So describes z. B. the DE 102 16 524 A a chain drive with two side by side and on multiple sprockets arranged drive chains. Such multiple sprockets are either formed in several pieces, wherein a plurality of single sprockets are connected to each other, but also in one piece, wherein a wheel body has a plurality of single gears with corresponding teeth on the outer peripheries. The tooth geometry is determined both in the one-piece and in the multi-piece variant in the manufacturing process. It is therefore necessary to keep suitable molds and tools for each multi-sprocket with the particular tooth geometry.

Object objective invention is to provide a way to make the production of multiple wheels for a traction drive variable.

This object of the invention is solved by a method having the features of claim 1 or by a multi-wheel with the features of claim 5.

With the aid of the invention, the respective desired wheel, for example gear wheel, sprocket or toothed belt wheel, can be produced from a preform depending on the intended traction means, so that it is possible to prefabricate corresponding preforms independently of the final tooth geometry, thereby responding more quickly to customer demand can, in which only the appropriate deformation in the final tooth geometry is required. It is thus possible to produce these preforms in stock, so that production bottlenecks can be compensated by appropriate pre-production in times of lower capacity utilization. The invention is thus to be seen in the fact that either the finished tooth contour of the chain or gear or the finished tooth contour of a toothed belt wheel is produced from the raw contours. The non-cutting shaping, in particular the rolling, is also achieved that the material waste in comparison to previous manufacturing processes in which the tooth geometry has been made from the original mold, can be significantly reduced. In addition, it is also relatively easy to produce multiple wheels that can not be produced with normal sintering or only with significantly higher cost, such as a triple wheel, in which the middle single wheel has a smaller diameter than the two marginal single wheels.

According to one embodiment variant of the method, the tooth height can be reduced before the forming, so that the variability of the tooth contour to be determined can be increased. It can thus be better responded to different diameters of single wheels.

According to one embodiment of the preform according to the invention it is provided that the rough contour of the teeth is at least approximately evolvent-like, whereby the non-cutting deformation, so the material displacement, can be facilitated. It can thus be achieved with a lesser degree of wear of the forming tools or forming machines.

The preform may further consist of a sintered metal or a sintered metal alloy. It is advantageous, since such components have a more or less high porosity after the sintering, that the deformation can be facilitated in which the porosity is lowered at least in the outer region, that is, the component is compressed in these areas. Due to the higher density in the outer area of the component can also achieve a better wear resistance. In addition, a smoothing of the surface or a better surface quality is thus achieved, for example, the teeth have no transverse grooves, as they normally arise during the compression of a sintered metal powder due to the process.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

Fig. 1

eine Ausführungsvariante der Vorform als Zweifachrad in Schrägansicht;

Fig. 2

die Vorform nach Fig..1 in Stirnansicht;

Fig. 3

eine erste Ausführungsvariante der Zahnumformung;

Fig. 4

eine weitere Ausführungsvariante der Zahnumformung.

Each shows in a schematically simplified representation:

Fig. 1

an embodiment of the preform as a double wheel in an oblique view;

Fig. 2

the preform after Fig..1 in front view;

Fig. 3

a first embodiment of the tooth transformation;

Fig. 4

a further embodiment of the tooth transformation.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation.

All statements on ranges of values in the description of the present invention should be understood to include any and all sub-ranges thereof, e.g. is the statement 1 to 10 to be understood that all sub-areas, starting from the lower limit 1 and the upper limit 10 are included, ie. all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

The Fig. 1 and 2 show a preform 1 for producing a multi-wheel 2 for a traction mechanism drive. Such traction drives are, for example, chain drives or belt drives (belt drive).

That from the preform 1 after FIG. 1 produced Mehrfachrad 2 has two single wheels 3, 4. Each of these single wheels 3, 4 comprises a wheel body 5, 6 with an outer circumference 7, 8 over which distributed teeth 9, 10 are arranged for engagement of the traction means.

In this embodiment of the multiple wheel 2, the two single wheels 3, 4 have a different diameter 11, 12 (FIG. FIG. 2 ) on. Of course, it is possible that the two single wheels 3, 4 have the same diameter 11, 12.

Furthermore, it is possible that the multiple wheel 2 not only has two single wheels 3, 4 but that more than two, for example. 3, 4, 5, etc. multiple wheels 3, 4 are arranged. Also, there is the possibility that these single wheels 3, 4 have a different diameter or all single wheels 3, 4 have the same diameter, or more than two. In preferred embodiments, the multi-wheel 2 has two three single wheels 3, 4 with decreasing diameter 11, 12, wherein the teeth 9 of the single wheel 3 with the largest diameter 11 and optionally subsequent thereto single wheel are designed for a chain drive and the smallest single wheel 4 for the engagement of a toothed belt is formed.

As in the Fig. 1 and 2 can be seen, the multi-wheel 2 has a central bore 13 for receiving a shaft or the like.

In the preferred embodiment, the multi-wheel 2 or the preform 1 of a Formed sintered metal or a sintered metal alloy. These may be formed, for example, on an aluminum, iron, copper, magnesium base. Examples of such sintered metal alloys can be found in DIN V 30 910 Part 4, page 3.

Since the person skilled in the principle of production of sintered components is known, reference is made at this point to the literature. In particular, the production of sintered components comprises the process steps mixing the powder, optionally with additives and auxiliaries, powder compaction to a green compact, sintering of the green compact, optionally calibration and / or densification of the sintered component.

FIG. 3 shows a first embodiment variant for the transformation and final production of the tooth contour for the multi-wheel 2. This is in FIG. 3 only one tooth 10 is shown. In particular, its tooth contour 14 is called a contour for a toothed belt, hereinafter toothed belt wheel contour 15, as a contour for a toothed chain, hereinafter referred to as sprocket contour 16 (dashed line) and shown as a rough contour 17 (dash-dotted line). The rough contour 17 is preferably produced as a rough contour 17 for the production of teeth 10 for engagement of a toothed chain. In particular, this is the rough contour 17 after sintering of the respective preform 1.

How out FIG. 3 it can be seen, the rough contour 17 of the tooth 10 in the region of a tooth flank 18 is thicker than a tooth flank thickness 19 of the finished tooth 10 for engagement of a toothed chain. For the final production of the tooth 10 from this rough contour 17 takes place a non-cutting deformation, wherein the material from the region of the excess of the tooth flank 18 in a tooth tip region 20 is at least partially spent. At the same time, in this deformation, a compression in the peripheral region of the tooth 10 of the sintered material can take place.

In order to produce a tooth 10 for engagement of a toothed belt (toothed belt wheel contour 15) from this rough contour 17, the deformation is designed so that at least part of the excess material of the rough contour 17 is again moved in the area of the tooth flank 18 in the direction of the tooth head region 20, However, after the teeth 10 for the engagement of a toothed belt, in principle, look different from the teeth 10 for engagement of a toothed chain, the tooth flank region 21 adjoining the tooth tip region 20 is broadened with respect to the rough contour 17 and, if necessary, also made of material during this deformation In the tooth neck region, the toothed belt wheel contour 15 can overlap with the rough contour 17 of the tooth 10.

It should be mentioned at this point that the illustrated embodiment has only exemplary character, so that the final tooth geometry can be quite different from the illustrated. In that respect should FIG. 3 merely to illustrate the principle of the production of the multiple wheel 2 from the preform 1 ( FIG. 1 ) serve.

The rough contour 17 is in the variant after FIG. 3 formed approximately involute, whereby the advantage is achieved that sufficient material for the forming and / or compression is available to make it, as needed, a tooth 10 for a toothed chain or a toothed belt. The maximum extent of the excess width in the region of the tooth flank 18 can have a value (in each case left or right oversize) which is selected from a range with an upper limit of at most 25%, based on the tooth flank thickness 19 of the sprocket contour 16 of the tooth 10. This upper limit is to be understood that the excess over the height of the tooth flank 18 is variable and can be based on the particular desired tooth geometry. Of course, the oversize for relatively slender, small teeth 10 is different than for thicker, larger teeth 10. Compared over the entire tooth geometry of the finished tooth 10, the excess may range from -25% to + 25%, especially -20% to + 20%, fluctuate, as suggested Fig. 3 is apparent.

Although in this embodiment, the preform 1 is symmetrical with respect to the tooth geometry, there is also the possibility that the extent of the oversize of the rough contour 17 with respect to the sprocket contour 16 on the left tooth flank is different from the right flank.

The single wheel 3 is formed in this variant as a sprocket, but may also be a gear. This single wheel preferably already has its final shape prior to forming the teeth 10 of the second single wheel 4.

In FIG. 4 an embodiment of the invention is shown in which the tooth 10 of the Toothed belt wheel contour 15 (full lines) compared to the tooth 10 of the sprocket contour 16 (dashed lines) has a significantly lower tooth height 22. In order to enable this difference 23 (for example, the tooth 10 of the toothed belt wheel contour 15 can have a tooth height 22 that is half the tooth height 22 of the sprocket contour 16), a part of the tooth 10 in the tooth head region 20 is removed by machining, since such a large tooth Reduction can not be accomplished by forming alone. The removal of the material of the tooth 10 follows, for example. By turning up to a tooth height 24 of the rough contour 17 (dash-dotted lines). The tooth 10 of the toothed belt wheel contour 15 produced by the deformation has after the deformation in comparison to the embodiment according to FIG. 3 a larger tooth height 22 than the tooth height 24 of the rough contour 17, so it is more material removed than would be required solely due to the tooth height. This ensures that the material can be moved from the tooth flank region 18 in the region of the tooth head by the deformation.

Both off FIG. 3 as well as out FIG. 4 It can be seen that, depending on the deformation, the steepness of the tooth flank and the region of the tooth head are changed (steep tooth flank and wider tooth head for toothed belt drive in comparison to the toothed chain drive).

The forming itself is plastic, in particular by rolling. On the other hand, it is also possible to carry out the forming by means of split dies, wherein a pressure is applied laterally to the corresponding rough contour 17 via the divided die and thus the material displacement is carried out in the corresponding area. The forming itself can be carried out both as hot forming and as cold forming.

With the aid of the method according to the invention, it is therefore possible to provide preforms 2, from which a multiple wheel 1 with at least one toothed, toothed belt or sprocket can be produced as required, the latter being produced from the preform 2 by non-cutting shaping. So it can be made of a contour for a toothed belt or a sprocket, a sprocket from a contour for a toothed belt or a gear or a gear from a contour for a toothed belt or sprocket a timing belt from a contour, where necessary, the rough contour of the Preform 2 also in the respective final contour for the originally envisaged teeth 9, 10 can be finished without cutting, so from the preform 2 for a gear a gear, the preform 2 for a sprocket sprocket or the preform 2 for a toothed belt a timing belt ,

The embodiments show a possible embodiment of the method, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof.

For the sake of order, it should finally be pointed out that in order to better understand the structure of the preform 1, these or their constituents have been shown partly unevenly and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

REFERENCE NUMBERS

1

preform

2

multiple wheel

3

single wheel

4

single wheel

5

Wheel center

6

Wheel center

7

scope

8th

scope

9

tooth

10

tooth

11

diameter

12

diameter

13

drilling

14

tooth contour

15

toothed belt wheel

16

sprocket wheel

17

rough contour

18

tooth flank

19

Tooth flank thickness

20

Tooth head area

21

Tooth flank region

22

tooth height

23

difference

24

tooth height

Claims (5)

1. Method of producing a one-piece, metal multiple wheel (2) for a traction mechanism comprising at least two adjacently disposed single wheels (3, 4), each comprising a wheel body (5, 6) having an outer circumference (7, 8), and teeth (9, 10) for engaging the traction mechanism are arranged in a distributed manner around the outer circumference (7, 8), and at least one of the at least two single wheels (3, 4) is configured as a sprocket, gear or toothed belt wheel, and the sprocket, gear or toothed belt wheel is produced with a rough contour (17), and a tooth thickness of the rough contour (17), in axial view, is thicker than the tooth thickness of the final contour of the finished sprocket, gear or toothed belt wheel and thereafter, depending on the traction means used, this rough contour (17) is reformed by non-machining reforming, in particular by rolling, into the finished tooth contour, characterised in that a toothed belt wheel contour is produced from a sprocket wheel or gear wheel contour, or a sprocket wheel contour is produced from a gear wheel or toothed belt wheel contour, or a gear wheel contour is produced from a toothed belt or sprocket wheel, and to this end, at least some of the surplus material of the rough contour (17) in the region of a tooth flank (18) of the teeth (9, 10) is moved in the direction towards a tooth tip region (20).
2. Method as claimed in claim 1, characterised in that the tooth height is reduced prior to reforming.
3. Method as claimed in claim 1 or 2, characterised in that a preform (1) is used, the rough contour (17) of which contains surplus material, with a thicker tooth thickness, in axial view, in the region of the tooth flank (18) than the tooth thickness of the finished tooth contour, and the surplus material of the entire tooth geometry fluctuates compared with the finished tooth geometry by in the range of between - 25% and + 25 %.
4. Method as claimed in claim 3, characterised in that a preform (1) is used, the rough contour (17) of which for the teeth (10) is of an at least approximately involute design.
5. One-piece, metal multiple wheel (2) for a traction mechanism comprising at least two adjacently disposed single wheels (3, 4), each comprising a wheel body (5, 6) having an outer circumference (7, 8), and teeth (9, 10) for engaging the traction mechanism are arranged in a distributed manner around the outer circumference (7, 8), and the two single wheels (3, 4) are configured as a sprocket, gear or toothed belt wheel, with the proviso that the two single wheels are configured for engaging different traction means, and at least one of the two single wheels is produced by non-machining reforming, in particular by rolling, from a rough contour (17) for a sprocket, gear or toothed belt wheel, characterised in that a toothed belt wheel contour is formed from a sprocket wheel or gear wheel contour to produce the at least one single wheel, or a sprocket wheel contour is produced from a gear wheel or toothed belt wheel contour, or a gear wheel contour is produced from a toothed belt or sprocket wheel, and to this end, at least some of the surplus material of the rough contour (17) in the region of a tooth flank (18) of the teeth (9, 10) is moved in the direction towards a tooth tip region (20).

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