WO2006010602A2

WO2006010602A2 - Assembled gearwheel

Info

Publication number: WO2006010602A2
Application number: PCT/EP2005/008145
Authority: WO
Inventors: Matthias BÖNING
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2004-07-27
Filing date: 2005-07-27
Publication date: 2006-02-02
Also published as: WO2006010602A3; DE102004036336A1

Abstract

An assembled gearwheel is disclosed, for which the teeth (1) and a toothed wheel body (17) are produced from different materials. It is thus possible to economically produce high-load gearwheels with low requirement for complex devices and machines, whereby said gearwheels as a rule are much easier to produce than conventional gearwheels produced from one workpiece.

Description

Title: Built gear

description

The invention relates to a gear with a hub having a plurality of teeth and with a hub and ring gear connecting gear body and a rack.

Usually gears are worked out, for example, from a forging blank or a cast blank or from the solid. This means that, first, the manufacturing cost is very large and second, with the exception of the hub, the entire gear is made of a, usually very high quality and expensive material. Since these materials usually have a high specific gravity, the total weight of the known from the prior art gears is usually relatively high.

From US 5,203,861 a sprocket is known, which has a base body with distributed over the circumference recesses. The main body is made of plastic. In the recesses of the body teeth can be inserted laterally, which are held by frictional engagement in the body. In this sprocket, both the gear body and the teeth are designed pictorially in separate manufacturing processes and only then joined together. A disadvantage of this sprocket is its relatively low load capacity.

The invention has for its object to provide gears and racks that can be made easier and cheaper and their weight is significantly reduced compared to conventional gears or racks. The load capacity of a conventional gear made of steel should be approximated. In addition, the production of various gears, the

BESTÄTIGUWGSKQPSe means gears with different modules and different numbers of teeth, to be possible without the need of expensive gear milling machines.

This object is achieved with a gear having a hub, with a plurality of teeth and with a hub and ring gear connecting gear body, with the characterizing features of claim 1. Thus, it is possible to produce the teeth, for example, from high-strength hardened steel, while the gear body Alloy or plastic is produced. In the manufacture of the gear, the individual teeth are initially designed pictorially. By means of a primary molding process, the teeth are firmly connected to the gear body in the subsequent production of the gear.

A particular advantage of this built gear is that, regardless of the number of teeth of the gear to be built, only one type of tooth must be made for each module. These tooth types can be produced, for example, as a drawn profile, forged part or by investment casting and are then cut to the desired tooth width. This cutting can be done for example by sawing, milling or other separation process. In other words, with a very manageable number of different teeth, which differ only in terms of the module, gears in any size and tooth widths can be made economically even in the smallest series or even as individual pieces.

Characterized in that the material of the gear body is different from the material of the teeth, in the low-loaded gear body, a lightweight material that is easy to work, are used, so that firstly the manufacture of the gear is simplified and the moment of inertia of a gear according to the invention compared to a conventional, made of a material, gear is significantly reduced.

The teeth of the gear constructed according to the invention can be produced by cutting to length a corresponding extruded profile or, alternatively, be made by investment casting or sheet metal forming. Which of the above or other manufacturing methods is given preference in individual cases depends on the loads and the other boundary conditions and must be decided on a case-by-case basis.

In a further advantageous embodiment of the invention, the teeth have a U-shaped cross section with two legs, wherein the tooth flanks of the teeth are part of the legs. This construction allows on the one hand the formation of a snap connection to the teeth to secure the teeth to a ring and on the other hand it allows a particularly good positive and resilient connection between the teeth and the gear body. As a result, the load capacity of the gear according to the invention is increased.

To ensure that the teeth with the gear body enter into a durable and resilient connection, a fastener is provided at the foot of each tooth. This fastener is formed integrally with the tooth, so that it can not lead to a separation of tooth and fastener.

Advantageously, such a fastening element has at least one projection and / or at least one recess, so that a positive connection with the gear body is possible. In order to reduce the notch effect can be seen in that the transitions between the projection and / or the recess are rounded and have a radius. In order to achieve a very strong connection between the gear body and the tooth, the fastening element preferably extends over the entire tooth width. Alternatively, the fastener may also be formed pin-shaped. This can be advantageous if a helical gearing is to be produced and thus the teeth must be rotated relative to the gear body.

A particularly advantageous embodiment of the invention provides that the fastening element is designed as part of a snap connection. In this case, snap connections with closed or interrupted Formschiusswirkflache are possible. If the fastener is formed as part of a snap connection with interrupted Formschlusswirkflache, the tooth can be made very economically, for example by extrusion or (sheet) forming on the one hand and on the other hand, by the snap connection of the tooth on a ring, this ring with the pre-assembled teeth can subsequently Also very simple way to be connected to the gear body and the scar, so that there is an easy to manufacture yet very precise built gear.

It has proved to be advantageous if the legs of the tooth are designed as Schnapphacken.

Alternatively, it is also possible that fastener form a slot, wherein the slot extends over only a part of the width of the tooth.

It has proved to be particularly advantageous to produce the gear body made of plastic, in particular a thermosetting or thermoplastic plastic, or metal, in particular light metal. The use of plastic in the gear body, the strength and damping properties as well as the Resilience of the gear body can be adjusted within wide limits to the requirements of a specific application, so that there is an optimal performance of the gear according to the invention in almost all situations.

Through the use of metal, in particular light metal, for the construction of the gear body high loads can be transmitted at the same time low weight.

In addition, it is readily possible and particularly advantageous to produce the gear body by extrusion. This results in a very high precision at the same time low weight of the gear body.

In order to achieve a highly resilient connection between the gear body and teeth, the invention is provided in a further supplement that the gear body and the fastening elements of the teeth are positively and / or materially connected to each other.

On the one hand to simplify the production and on the other hand to increase the capacity of the built-in gear according to the invention, can be provided in a further supplement of the invention to connect the teeth of the gear by a ring. This ring may for example consist of a bent sheet metal strip or be shaped like a washer, wherein recesses are provided on the outer diameter or the inner diameter of this washer, which form a positive connection with the fastening elements of the teeth.

In an advantageous further embodiment of the ring according to the invention it is provided that it has slots for receiving the teeth. This makes it possible to position the teeth in a simple manner relative to each other and at the same time the diameter of the ring through the diameter of the ring To set gear. This simplifies the manufacture and improves the accuracy of the built-up gear according to the invention. A similar effect can also be achieved if the recesses in the ring interact with the legs of the teeth designed as snap hooks so that the teeth can be resiliently engaged in the recesses. This results in a snap connection between the ring and the teeth, which also has the advantage of a further increased load capacity with respect to the torque transmission from the teeth to the gear body in addition to the advantages mentioned. Also, this variant is very easy to automate, since snap connections can be easily added nowadays by handling facilities fully automated.

Regardless of the design of the ring, the ring and the teeth can be welded, glued or soldered together. This ensures in each case that the teeth have the correct distance from each other, this distance ultimately being determined by the modulus of the teeth. It is therefore possible to equip, for example, an endless metal strip with teeth and then, depending on the number of teeth of the gear to be built, cut a piece of this sheet metal strip, to bend this metal strip in a circle and to weld the joint parts. Subsequently, this structure is potted with the gear body and a hub mounted in the gear body.

The inventively constructed gears may be straight-toothed or helical teeth, they may have an involute or cycloid teeth and can be designed both as a spur gear and as a gear with internal teeth. Also worm wheels or helical gears are possible. It is also possible to form the gear as a toothed segment. It goes without saying that gears with an infinitely large pitch circle diameter are possible, so that the gear according to the invention passes into a built rack.

The object according to the invention is also achieved by a method for producing a toothed wheel with a plurality of teeth, with a hub and with a toothed wheel body by the following method steps:

- Making multiple teeth, each tooth has a fastener.

- Arranging the teeth in the desired position and filling the gap between the hub and the teeth with a pourable or moldable material, so that the fastening elements of the teeth are enclosed by the potting compound.

By this method according to the invention gears of different diameters and numbers of teeth as well as with different modules can be produced in a simple manner and without the use of complicated and expensive Zahnradfräsmaschinen.

Alternatively, gears according to the invention can also be produced by making a plurality of teeth in a first step, wherein each tooth has a fastening element, in a second step a prismatic gear body is produced, wherein the toothed body has a means for positively securing a tooth per tooth, and that subsequently the teeth are fastened by means of the fastening elements in the gear body.

This makes it possible to produce a metallic gear body, for example made of aluminum or other light metal, and to connect the teeth firmly and positively with the gear body. It is it is possible to make the gear body as wide as the tooth width of the teeth or alternatively cut out the gear body from a sheet, for example by laser cutting. In this case, it is possible, for example, by stacking a plurality of such sheet metal blanks, to make the gear body so wide that the teeth are sufficiently firmly connected to the gear body. An advantage of this variant is that no tool for extrusion must be produced, but can be produced by a comparatively easily programmable control program for a laser cutting machine, gear body for a variety of pitch circle diameter and hub diameter if required. This variant is characterized, among other things, by particularly low tool and machine costs.

To complete the gear according to the invention can be provided to attach a hub in the gear body. This hub may be designed as plain bearings or rolling bearings, as well as the hub may also have a splined, a groove for a key or other means for transmitting torque between the gear according to the invention and a shaft to which the gear is pushed, have.

The gear body can be produced by prototyping or forming, in particular by extrusion, or by cutting out of a metal sheet.

The teeth can be made by extrusion, casting or forging or other molding process.

It is particularly advantageous if the teeth are hardened and / or ground. If the highest demands are placed on the accuracy of the teeth, the teeth can also after connecting the teeth with the gear body, that is, when the gear according to the invention already finished, sanded or lapped. As a result, manufacturing inaccuracies are compensated and the gear quality of a gear according to the invention corresponds to that of a one-piece conventional gear.

Further advantages and advantageous embodiments of the invention, the following drawings, the description and the claims are taken. All of the features disclosed in the drawing, the description and the claims can be essential to the invention both individually and in any combination with one another.

Show it:

1 shows a tooth according to the invention in an isometric view;

Figure 2 shows a first embodiment of a gear according to the invention in a side view;

Figure 3 is an isometric view of the gear of Figure 2;

Figure 4 more, attached to a metal strip

Teeth;

Figure 5 shows a second embodiment of a gear according to the invention;

Figure 6 shows a third embodiment of a gear according to the invention;

Figure 7 is a manufactured by extrusion or laser cutting gear body in a side view; FIG. 8 shows the gear body according to FIG. 7 in an isometric view;

FIG. 9 shows a toothed rack according to the invention;

Figures 10 -15 representations of further embodiments of inventive gears and their components.

Description of the embodiments

Figure 1 shows a tooth according to the invention, which was provided in its entirety by the reference numeral 1 in an isometric view. The tooth 1 has two tooth flanks 3, a tooth head 5 and a tooth root 7. At the tooth root 7, a fastener 9 connects. The fastening element 9 shown in Figure 1 is symmetrical and has three projections 11 and two recesses 13 on each side. As a result, as shown in FIG. 2, a highly loadable, positive connection with a gear body (not shown) is possible.

The tooth flank 13 may be formed as involute or cycloidal. Other tooth shapes are also possible.

In the embodiment according to FIG. 1, both the tooth flanks 3 and the fastening element 9 with their projections 11 and recesses 13 extend over an entire width B of the tooth 1. In other words, the tooth 1 with the fastening element 9 is a prismatic body which can be produced particularly well by extrusion or rolling. Depending on the desired tooth width B, a tooth 1 is produced from this profile material by cutting to length.

In order to reduce the notch effect, the transitions between the projections 11 and the recesses 13 may also be rounded. However, it is also possible, the fastening element 9 as a radially arranged pin (not shown) form. This pin-shaped fastening element preferably also has projections 11 and / or recesses 13, so that a positive connection with the gear body is possible.

2 shows a first embodiment of a gear according to the invention is shown in a side view. This gear consists of a plurality of teeth 1 according to Figure 1. In the center of the gear, a hub 15 is provided. This hub 15 may be formed as a plain bearing or roller bearings when the gear is rotatably mounted on a shaft, not shown.

If torques are to be transmitted between the shaft and the gear, not shown, the hub 15 is formed accordingly. For example, a toothing (not shown) may be provided. Alternatively, a groove (not shown) may be provided in the hub 15 in which a key or a disc spring is inserted. The design of the hub 15 may have any known from the prior art shape and expression in a gear according to the invention.

Between the hub 15 and the teeth 1 of the gear is the gear body 17. In the present

Embodiment, the gear body 17 consists of a potting compound, for example, if necessary, fiber-reinforced resin.

The gear shown in Figure 2 is prepared by the teeth 1 and the hub 15 are arranged in the desired position and then the space between the teeth 1 and hub 15 are filled with a potting compound. It is important that the fastening elements 9 of the teeth 1 are completely surrounded by the potting compound, so that a very reliable positive and cohesive connection between the gear body 17 and the teeth 1 results. It goes without saying that the connection between teeth 1 and gear body 17 is of crucial importance for the load capacity of the gear according to the invention. By a suitable choice of the material of the gear body 17, the strength, the vibration behavior, the weight and the

Damping properties of the gear can be adjusted within wide limits to the intended application.

It is also possible, if the highest demands are placed on the precision of the teeth to grind after the casting of hub 15 and teeth 1, the tooth flanks 3 of the teeth on a conventional gear grinding and / or fine machining the tooth flanks by lapping. As a result, the gear according to the invention can meet the highest requirements with regard to the quality of the toothing.

In Figure 3, the previously described gear is shown again in an isometric view. From this representation it is clear that the gear body 17 extends over the entire tooth width B of the teeth 1. As a result, a very durable and durable connection of the teeth 1 with the gear body 17 is possible.

In the embodiment according to Figures 2 and 3 is a spur gear. However, the invention is not limited to spur gears or racks, but can be used with the same advantages in helical gears (not shown). It is advantageous if the individual teeth 1 are formed as a prismatic body in order to enable economical and efficient production of the individual teeth 1. On the basis of the first embodiment according to Figures 2 and 3 it is clear that with a type of teeth 1 gears with different numbers of teeth without complicated and expensive manufacturing equipment can be produced. It only needs to be in stock of one type of teeth 1 with the desired module, for example in the form of a profile bar. From this profile bar teeth 1 are then cut to the desired tooth width B and joined together with the hub 15 and the gear body 17 to form a gear.

FIGS. 4 and 5 show a variant of a production method according to the invention. In this manufacturing method, the teeth 1 are mounted on a metal strip 19 at the desired distance. The teeth 1 can be connected by welding, soldering or gluing with the metal strip 19. Alternatively, it is also possible by a snap connection (not shown) to lock the teeth with the metal strip 19. In FIG. 4, welding seams or spot welds which connect the teeth 1 to the sheet metal strip 19 are identified by the reference numeral 21. The metal strip 19 may have one or more holes 23 so that the metal strip 19 is permeable to the potting compound. In a further manufacturing step, the metal strip 19 is bent into a circle and welded to the resulting impact 26. Subsequently, the teeth 1 and the metal strip 19 with the hub 15 in a similar manner as in the

Embodiment shed according to Figure 2 and 3. FIG. 5 shows a side view of this embodiment of a gear according to the invention.

This variant simplifies the exact positioning of the teeth 1 and at the same time allows the transmission of larger forces between the teeth 1 and the gear body 17. It is also possible in this embodiment, to secure the teeth 1 on an endless metal strip 19 and, if necessary, a metal strip 19 in to cut off the required length and turn into a ring. As a result, gears can be produced in a particularly simple manner as individual pieces or in small series without great tool and machine costs.

It is also possible, for example, abroad or if a damaged gear is not available to produce a damaged gear by a novel, newly manufactured gear on site.

6 shows a further embodiment of a gear according to the invention is shown in a side view. In this embodiment, the teeth 1 are held in position by a ring 25. The ring 25 has the form of a washer in this embodiment. For each tooth 1, a recess 27 is provided in the ring 25, which allows a positive connection with the fastening elements 9 of the teeth 1.

Such a ring 25 can be cut out of a metal sheet, for example by laser cutting. When such a program has been created to control a ^'laser cutting machine, less dimensions of the ring 25 and the module of the teeth 1 inserted, the number of recesses can be determined 27 and the ring 25 be tailored made for the desired application by simply changing. This variant has the advantage that the tool costs are almost negligible and nevertheless a very precise positioning of the teeth 1 is made possible. In addition, because of the positive connection between the fastening elements 9 and the ring 25, the load capacity of the teeth 1 is very high.

If necessary, a plurality of rings 25 made of sheet-metal blanks 25 can be superimposed to further increase the load capacity of the gear. Particularly advantageous in this variant is that by Twisting two such superposed rings against each other an inclination of the teeth 1 and thus a helical gear can be achieved in a simple manner.

If desired, the teeth 1 can also be welded to the ring 25. The welds are not shown in Figure 6 for reasons of clarity. This results in a further increased load capacity of the gear according to the invention.

Subsequently, the teeth 1 and the ring 25 are potted together with the hub 15 in the manner already described, so that between the hub 15 and the teeth 1 of the gear body 17 is formed.

In this embodiment, a particularly good introduction of force from the teeth 1 via the ring 25 in the gear body 17 is possible. Due to the number of rings 25, their distance from each other and the nature of the connection between teeth 1 and rings 25, the properties of the gear according to the invention in terms of its elasticity, its damping behavior and its capacity in a wide range of the desired application can be adjusted.

FIG. 7 shows a further exemplary embodiment of a gear body 17 according to the invention. This gear body 17 can be produced by extrusion. In this case, it is very advantageous if the gear body 17 is made of aluminum or another light metal suitable for extrusion. This results in a very high weight saving and the precision of a provided with such a gear body 17 gear according to the invention is very high. In this embodiment, the hub 15 is equal integrated in the gear body 17, which brings more weight and cost advantages. In the recesses 27 of the gear body 17 shown in Figure 7 teeth according to Figure 1 can be inserted. Advantageously, an interference fit between the recesses 27 and the fastening elements 9 of the teeth 1 (see FIG. 1) is provided. Alternatively, however, it is also possible to press the teeth with the gear body 17, to glue or to connect permanently to the gear body 17 by means of a spot weld.

As an alternative to producing the gear body 17 from an extruded profile, it is also possible to construct the gear body 17 by cutting from a plurality of sheets quasi-layer by layer. As a result, the production of an extrusion die is avoided and by a suitable programmable programming of the controller, such as a laser cutting machine, gears with different numbers of teeth and pitch circle diameter can be made in the simplest way and without significant additional costs. As a result, it is also possible, for example for repairing a machine, when an original spare part is not available, to manufacture a gearwheel as a one-off product quickly and inexpensively.

In FIG. 8, the exemplary embodiment according to FIG. 7 is drawn in an isometric view without teeth 1.

FIG. 9 shows a gearwheel according to the invention with an infinitely large pitch circle diameter. This means nothing else than that the gear has gone into a rack. It is obvious that by the appropriate arrangement of teeth 1 in a uniform distance from each other and subsequent casting of these teeth 1, the production of built racks or toothed segments in a simple manner possible. An advantageous embodiment of this rack according to the invention provides that the teeth 1 on a Sheet metal strips 19 are arranged, which simplifies the casting or the positioning of the teeth. With regard to the attachment of the teeth 1 on the sheet metal strip 19, the statements made in connection with FIGS. 4 and 5 apply correspondingly.

In the rack according to Figure 9, the potting compound between the teeth 1, which also surrounds the metal strip 19, provided with the reference numeral 30.

Both with gears and with racks, the potting compound 30 may consist of thermoplastics, thermosets and / or metal foams.

Finally, it should be noted that with the method according to the invention also built internal gears gearing can be produced. In this case, for example, on a ring 25, the recesses 27 (see Figure 6 or 7) are not provided on the outer diameter but on the inner diameter. Again, shows the flexibility and variability of the gear according to the invention, since it can be dispensed with the use of hobbing or gear grinding machines.

FIG. 10 shows a tooth 1 with a U-shaped cross-section. In this case, both the tooth flanks 3 and the fastening elements 9 form the two legs (without reference numerals) of the U-shaped cross section. In the area of Befestigungselernente 9, a slot 29 is provided which does not extend over the entire width B of the tooth 1. In the embodiment shown in FIG. 10, the slot 29 has approximately a depth which corresponds to half the width B of the tooth 3. Alternatively, it would also be possible to provide a slot of correspondingly reduced depth at both ends of the tooth 1. This embodiment is not shown. Because of the U-shaped cross-section of the tooth 1 according to FIG. 10, one slot 29 is provided in each of the two legs of the tooth 1. FIG. 11 shows a cylindrical ring 25 which has various slots 31. These slots 31 of the ring 25 are matched with the slots 29 of the tooth 1 (see FIG. 10) with respect to depth and width and spacing such that the teeth 1 according to FIG. 10 can be pushed onto the ring 25 according to FIG. As a result, first, the teeth 1 are positioned relative to each other and in the desired diameter. In addition, can be derived from the teeth 1 by the positive connection formed by means of the slots 29 and 31, the force acting on the teeth during operation bending moment in the ring 25. This increases the load capacity of the built-up gear. In addition, when the ring 25 equipped with the teeth 1 is poured into a gear body (not shown), the rigidity of the teeth 1 can be increased and the load capacity of the gear can be increased as a whole. This effect is due to the positive connection between teeth 1 and ring 25 but also the good positive connection to the gear body (not shown) when it is poured in the interior of the ring 25 and below the tooth flanks 3 of the teeth 1.

In Figure 12, a ring 25 is shown in the several teeth 1 were inserted. From this presentation, the advantages mentioned above become clear. The gear body is not shown in this embodiment.

FIGS. 13 to 15 show a further exemplary embodiment of a built-up gear according to the invention. Also in this embodiment, the teeth 1 have a u-shaped cross-section, which allows the two legs (without reference numerals) of the U-shaped cross section to be elastically deformed towards each other elastically when the snap connection between the tooth 1 and the ring 25 (FIG. see FIG. 14). In this Embodiment, the fastening element is designed as a snap hook 33. In addition, a stop 35 is formed on both legs of the tooth 1, which on the one hand ensures that the tooth 1 can not be inserted too deeply into the ring 25 (see FIG. 14). On the other hand, the stops 35 also serve to support the tooth 1 on the ring 25, so that during operation the tilting moment acting on the teeth 1 is best diverted into the ring 25.

In the ring 25 different recesses 27 are provided. In each of these recesses 27, a snap hook 33 of the tooth 1 according to Figure 13 engage. FIG. 15 shows a segment of a ring 25 into which several teeth 1 have been snapped. From this representation, it is readily apparent how the stops 35 on the one hand cause the radial fixing and positioning of the teeth 1 relative to the ring 25 and on the other hand initiate the bending moments acting on the teeth 1 during operation in the ring 25. Also in this embodiment, it is possible to produce a very powerful frictional and positive connection between the teeth 1 and the ring 25 on the one hand and the later added gear body 17 (not shown).

Since in this embodiment, even the teeth 1 can be filled with the same material as the gear body, this results in a particularly good introduction of force from the teeth 1 in the gear body, which further increases the performance of the gear according to the invention. In addition, a further weight saving can be realized by this type with U-shaped teeth.

In order to further increase the efficiency of the gear according to the invention, the gear body can also consist of a hollow sphere structure. The hollow spheres may consist of a metallic or ceramic material. For example, the hollow balls may consist of aluminum foam balls.

Such hollow spheres are manufactured, for example, in the fluidized bed process and are available on the market in various diameters. Usually, the hollow spheres are produced in diameter ranges from 3 mm to 4 mm, 6 mm to 7 mm and 9 mm to 10 mm.

In this case, the entire gear body 17 may consist of hollow balls. So that the hollow balls reaches the mechanical load capacity required for the transmission of torques, the intermediate spaces between the hollow balls can be filled with the potting compound 30. Hollow balls made of aluminum foam, which is infiltrated by the liquid potting compound of a polymer or another material, are particularly suitable for this variant.

In this variant, the hollow spheres serve to increase the strength of the gear body and at the same time to improve the heat dissipation from the teeth 1 in the gear body 17. As a result, the thermal load of the teeth 1 is reduced and also reduces the temperature at the contact point between the teeth 12 and the gear body 17. As a result, the potting compound 30 is protected from softening, which also has a positive effect on the load capacity of the gear.

Finally, the hollow ball structures have a high internal damping which contributes to a quiet running of the gear according to the invention and reduces the vibration excitation of a gear equipped with gears according to the invention.

Alternatively, it is also possible to connect the hollow spheres by sintering and / or soldering with each other and with the teeth 1, so that an intrinsically stable hollow sphere structure with minimal weight and high strength results. In this case, the Verguzssmasse 30 can be omitted.

By grading, the properties of the hollow sphere structure can be anisotropic, i. H. depending on the direction.

It has also proven to be advantageous if the gear body consists partially or completely of a metal foam. The filling materials (metal foams) are arranged in the region of the gear body in such a way that energy is removed from the structure-borne noise resulting from the meshing action and that, e.g. In the wave and thus in the conversion parts forwarded body sound component is reduced. In addition, the vibrations that occur during the use of gear, are effectively damped by the use of the filler metal foam.

Inter alia, metal foams based on iron, zinc, tin, lead, aluminum and their alloys are suitable. For the production of metal foams, various methods are conceivable, which are briefly explained below:

In the production of foam from the metallic melt, a distinction is made between discontinuous and continuous production

In the batchwise production, an aluminum melt is produced, which is excited by mechanical stirring of a powdery blowing agent for expansion. To increase the viscosity, the melt may additionally be treated with elements such as e.g. Calcium, to be spiked. The expansion takes place in a closed mold.

In the continuous production, a foaming agent (gas, solid) is supplied in a heated mold of a molten metal with a lance, resulting in foaming of the molten metal. To increase viscosity, the Melt additionally with additives, such as calcium, added. By suitable transformation of the still partially liquid foam, a solid foam material is produced.

To increase the strength and particle-reinforced metal foams are used. For this purpose, a cell-forming gas or gas mixture is introduced into a melt of metal with finely divided reinforcing agents. The accumulating at the surface of metal foam is removed and cooled so that it solidifies.

Alternatively, metal foams can also be produced from a solid semi-finished product. Four different methods can be considered in this regard. These differ essentially in the nature and integration of the introduced propellant.

In the generation of foam by evaporation of a volatile metal finely divided volatile metals are introduced in a foaming material. The total mass is heated to its melting point under atmospheric pressure and then subjected to low pressure. This has the consequence that the volatile metal evaporates and foams.

In foam generation by expansion of an enclosed gas, a capsule is filled with a corresponding matrix metal and a metal powder. Subsequently, the evacuation and flooding of the capsule is carried out with argon. During hot isostatic pressing of the capsule, the inclusion of argon under high pressure into the metallic matrix.

The generation of foam by splitting off a dissolved gas utilizes the effect that some metals for gases exhibit significant solubility jumps when exceeding phase boundaries. The dissolved in excess elements are released during remelting under atmospheric pressure and form gas bubbles, which are preserved at a correspondingly faster cooling.

Finally, foams can also be produced by decomposition of propellant powder. In the case of aluminum foams, for example, the starting products, i. a powder of an aluminum alloy (e.g., AlSil2) and a propellant of titanium hydride are mixed. In the subsequent manufacturing step, we compacted this mixture under controlled conditions to a semi-finished product (axial hot pressing or extrusion). By heating the semifinished product to just above its melting point, the metal is melted and triggered the gas release of the blowing agent and thus the actual foaming process. In this case, the volume of the semifinished product increases by a factor of 4, whereby a porous structure is formed (spherical and / or ellipsoidal pore shape). Manufacturing parameters would be e.g. Composition, structure, density distribution, porosity, etc.

Claims

claims

A gear having a hub (15), a gear body (17) connecting a plurality of teeth (1) and a hub (15) and teeth (1), the teeth (1) being made of a different material than the gear body (17). consist, characterized in that the gear body (17) and the teeth (1) are cohesively connected to each other.

2. Gear according to claim 1, characterized in that the gear body (17) at least partially consists of a potting compound (30), and that the potting compound

(30) partially surrounds the teeth (1).

3. Gear according to claim 1 or 2, characterized in that the gear body (17) consists at least partially of hollow balls.

4. Gear according to claim 3, characterized in that the potting compound (30) at least partially surrounds the hollow balls and the teeth (1).

5. Gear according to claim 3 or 4, characterized in that the hollow balls are connected to each other and to the teeth (1) of the gear by sintering and / or soldering.

6. Gear according to one of claims 3 to 5, characterized in that the hollow balls consist of a metallic or ceramic material.

7. Gear according to claim 6, characterized in that the hollow balls consist of aluminum foam.

8. Gear according to claim 1 or 2, characterized in that the gear body (17) consists at least partially of metal foam.

9. Gear according to one of the preceding claims, characterized in that the teeth (1) are designed as extruded profile or sheet metal forming part.

10. Gear according to one of the preceding claims, characterized in that the teeth (1) have a U-shaped cross-section with two legs (), and that the tooth flanks () of the teeth () are part of the legs ().

11. Gear according to one of the preceding claims, characterized in that on a tooth root (3) of each tooth

(I) a fastening element (9) is provided, and that the fastening element (9) is formed integrally with the tooth (1).

12. Gear according to claim 11, characterized in that the fastening element (9) has at least one projection

(II) and / or at least one recess (13).

13. Gear according to claim 11 or 12, characterized in that the fastening element (9) extends over the entire tooth width (B).

14. Gear according to claim 11 or 12, characterized in that the fastening element (9) is pin-shaped.

15. A gear according to claim 11, characterized in that the fastening element (9) as a slot (29) is formed, and that the slot (29) extends over only a part of a width (B) of the tooth (1).

16. A gear wheel according to claim 11, characterized in that the Befestigungselernent is formed as part of a snap connection with closed positive engagement surface.

17. Gear according to claim 11 or 12, characterized in that the fastening element as part a snap connection is formed with an interrupted positive engagement surface, and that the legs of the tooth (1) are designed as snap hooks (33).

18. Gear according to one of the preceding claims, characterized in that the gear body (17) made of plastic, in particular a thermosetting or thermoplastic plastic, or metal, in particular light metal.

19. Gear according to one of the preceding claims, characterized in that the gear body (17) is made by extrusion or laser cutting.

20. Gear according to one of the preceding claims, characterized in that the gear body (17) and the fastening elements (9) of the teeth are positively connected and / or cohesively connected to each other.

21. Cogwheel according to one of the preceding claims, characterized in that the teeth (1) of the gear made of steel, in particular hardened steel.

22. Gear according to one of the preceding claims, characterized in that the teeth (1) of the gear by a ring (19, 25,) are interconnected.

23. Gear according to claim 22, characterized in that the ring (25) is made of a bent sheet metal strip (19).

24. Gear according to one of claim 22 or 23, characterized in that the ring (19, 25) and the teeth (1) are welded together.

25. Cogwheel according to one of claims 22 to 24, characterized in that the ring (19, 25) has at least one recess (27) per tooth (1), and that the at least one recess (27) with the fastening element (9) of a tooth (1) forms a positive connection.

26. Gear according to claim 24, characterized in that the recesses () for receiving the teeth (), in particular for receiving the formed as snap hook legs of the teeth (1) are formed.

27. Gear according to claim 22 or 23, characterized in that the ring (25) has slots (29) for receiving the teeth (1).

28. Gear according to one of the preceding claims, characterized in that the gear is helically toothed.

29. Cogwheel according to one of the preceding claims, characterized in that the gear has an involute toothing.

30. Cogwheel according to one of the preceding claims, characterized in that the gear has a cycloidal toothing.

31. Gear according to one of the preceding claims, characterized in that the gear is a spur gear.

32. Gear according to one of the preceding claims, characterized in that the gear has an internal toothing.

33. Gear according to one of the preceding claims, characterized in that the gear is a worm wheel

34. Gear according to one of the preceding claims, characterized in that the gear is a helical gear.

35. Gear according to one of the preceding claims, characterized in that the gear is formed as a toothed segment.

36. Gear according to one of the preceding claims, characterized in that the pitch diameter of the gear goes to infinity and that the gear is formed as a rack.

37. A method for producing a gear with a plurality of teeth (1), with a hub (15) and with a gear body (17), characterized by the following method steps:

Producing a plurality of teeth (1), each tooth having a fastening element (9),

Arranging the teeth (1) in the desired position in a mold and

Filling the gap between the hub (15) and the teeth (1) with a pourable or sprayable potting compound (30), so that the fastening elements (9) of the teeth (1) are enclosed by the potting compound (30).

38. A method according to claim 37, characterized in that in the region of the gear body (17) in the mold before pouring with the potting compound (30) hollow balls and / or metal foam is introduced.

39. A method for producing a gear with a plurality of teeth (1), with a hub (15) and with a gear body (17), characterized by the following method steps:

Producing a plurality of teeth (1), each tooth having a fastening element (9),

Arranging the teeth (1) in the desired position in a mold and

Filling the gap between the hub (15) and the teeth (1) with hollow balls, and Connecting the hollow balls with each other and with the teeth (1) by sintering and / or soldering.

40. A method for producing a gear with a plurality of teeth (1), with a hub (15) and with a gear body (17), characterized by the following method steps:

Producing a plurality of teeth (1), each tooth having a fastening element (9),

Arranging the teeth (1) in the desired position in a mold and

Filling the gap between the hub (15) and the teeth (1) with a metal foam and

Filling the gear body (17) with a pourable or sprayable potting compound (30), so that the fastening elements (9) of the teeth (1) and the metal foam are enclosed by the potting compound (30).

41. A method for producing a gear with a plurality of teeth (1), with a hub (15) and with a gear body (17), characterized by the following method steps:

Producing a plurality of teeth (1), each tooth having a fastening element (9),

Producing a prismatic gear body (1), wherein the gear body (17) per tooth (1) has a means for the positive fastening of a tooth (1), and

Attaching the teeth (1) by means of the fastening elements (9) in the gear body (17).

42. The method according to claim 37 to 41, characterized in that a hub (15) in the gear body (17) is attached.

43. The method according to any one of claims 37 to 42, characterized in that the gear body (17) is produced by extrusion or laser cutting.

44. The method according to any one of claims 37 to 43, characterized in that the teeth (1) by profile drawing, casting, forging or forming, in particular sheet metal forming, are produced.

45. The method of claim 37 to 44, characterized in that the individual teeth (1) are produced by cutting a prismatic tooth blank.

46. The method according to any one of claims 37 to 45, characterized in that the teeth (1) are hardened and / or ground.

47. The method according to claim 46, characterized in that the teeth (1) are ground and / or lapped after connecting the teeth (1) to the gear body (17).