Quiet Gear Wheel and Method for Producing Such a Gear Wheel

Abstract

The present invention relates to a gear wheel containing at least one sintered material having a porosity, the gear wheel having, in addition to the porosity, another noise-reducing means.

Claims

1. A gear wheel comprising at least one sintered material with a porosity, wherein the gear wheel has, in addition to the porosity, another noise reducing structure.

2. The gear wheel as claimed in claim 1, wherein an at least partially acoustic decoupling of a tooth ring of the gear wheel and a hub is produced, along with a refraction of sound waves by a variation of density in the wheel body, which interrupts a transmission path of the structure-borne sound waves from the generation at the tooth ring to the hub and/or refracts, absorbs or reflects sound waves so that a structure-borne sound signal at an output in the form of a shaft of the gear wheel or a bore of the gear wheel seems less pronounced.

3. The gear wheel as claimed in claim 1, wherein there is a radial variation of a density in a wheel body of the gear wheel.

4. The gear wheel as claimed in claim 1, wherein a structure-borne sound is refracted, absorbed and/or reflected by chambers which are introduced in a wheel body of the gear wheel.

5. The gear wheel as claimed in claim 4, wherein the chambers are empty and/or filled with a medium selected from an oil and/or a loose powder.

6. The gear wheel as claimed in claim 1, wherein the gear wheel has at least one or more of the following noise reducing structures: a refraction, an absorption and/or reflection of sound waves by filled and/or unfilled chambers in the gear wheel, a combination of different densities and/or materials which extend in the radial direction to form ring-shaped, rings of different density and/or materials.

7. The gear wheel as claimed in claim 1, wherein an axial density variation is provided.

8. The gear wheel as claimed in claim 7, wherein the gear wheel has a disk-like construction of different densities.

9. The gear wheel as claimed in claim 1, wherein a sound channel runs in the gear wheel along which a structure-borne sound is guided.

10. The gear wheel as claimed in claim 9, wherein specifically introduced conduits as noise channels hinder a structure-borne sound from getting directly to an output in the form of a shaft or bore of the gear wheel.

11. The gear wheel as claimed in claim 9, wherein a material with a higher density forms the sound channel.

12. The gear wheel as claimed in claim 9, wherein the sound channel is provided with a material identical to the surroundings of the sound channel with a lesser porosity.

13. The gear wheel as claimed in claim 9, wherein the sound channel has rotational symmetry about an axis of rotation of the gear wheel.

14. The gear wheel as claimed in claim 1, wherein the gear wheel has a vibration-dampening coating.

15. The gear wheel as claimed in claim 1, wherein the gear wheel has a bracing, while the braces of the bracing have a vibration-dampening coating.

16. The gear wheel as claimed in claim 1, wherein one or more asymmetrical geometries are present in the gear wheel, which influence an eigenfrequency of the gear wheel.

17. The gear wheel as claimed in claim 1, wherein the gear wheel has a quality grade of the designed gear wheel per DIN 3961 and DIN 3962 in terms of at least one parameter selected from a total profile error F.sub.a, a profile angle error f.sub.Ha and/or a profile form error f.sub.a, of at least the gearing quality 6 or better.

18. A method for production of a gear wheel comprising the following steps: designing a sintered gear wheel using predetermined geometry and loading data, simulating a load computation and a noise prediction for the designed gear wheel, selecting at least one noise reducing structures as claimed in claim 1, verifying a load computation and a noise prediction, adapting of the gear wheel if necessary and repeating of at least the verifiying of the noise prediction or the load computation, drafting of manufacturing data and manufacturing of the gear wheel on the basis of the manufacturing data.

19. The method as claimed in claim 18, wherein several different noise reducing structures are simulated until a choice of one or more noise reducing structures is made with the aid of predetermined criteria.

20. The method as claimed in claim 18, wherein a quality grade of the designed gear wheel per DIN 3961 and DIN 3962 in terms of one parameter selected from a total profile error F.sub.a, a profile angle error f.sub.Ha and a profile form error f.sub.a, is adapted each time to the gearing quality 6 or better.

21. The method for production of a gear wheel as claimed in claim 18, wherein a selection of a manufacturing method is made from predetermined manufacturing technology, load analysis, and noise abatement aspects.

22. The method for production of a sintered gear wheel as claimed in claim 1, wherein at least one of the following manufacturing methods is used to form a noise reducing structure in the gear wheel: a surface rolling and/or surface compacting of the teeth to adjust a porosity from noise reduction aspects, a simultaneous arrangement of two or more different powders to be sintered jointly in the same pressing mold for the forming of a noise reducing structure in the gear, inserting of one or more bodies in and/or on a material to be sintered of the gear wheel to be produced, selected from a brace, a vibration system, a hollow body or a fluid-filled body.

23. A computer program product for the production of a gear wheel with computer program code on a data medium for executing a method as claimed in claim 18.

24. (canceled)

Description

[0057] The following figures show various sample embodiments of modified wheel bodies with which a noise reduction is possible. The details presented in the individual figures, however, are not confined to the particular embodiment. Instead, one or more features from one or more figures as well as from the corresponding and/or the above specification can be interrelated to other embodiments in order to realize a solution according to the invention. There are shown:

[0058] FIGS. 1 and 2: gear wheels resembling a composite gear wheel, consisting of several individual components produced by powder metallurgy with different densities,

[0059] FIG. 3: individual components with different densities in the axial direction which can be varied in their shape,

[0060] FIGS. 4 to 6: local, nonsymmetrically arranged density variations both in the radial and in the axial direction,

[0061] FIG. 7: a disk-shaped arrangement of elements of different density in the preferred direction,

[0062] FIG. 8: a disk-shaped arrangement of elements of different densities at an angle to a gear wheel axis,

[0063] FIG. 9: schematically, sound guiding channels in various configurations,

[0064] FIG. 10: a topology-optimized rod structure with dampening coated rods,

[0065] FIG. 11: one possible construction of a spring-mass cell, and

[0066] FIG. 12: a gear wheel according to the invention.

[0067] FIG. 1 and FIG. 2 show different designs of gear wheels 1 closed density variations 3 arranged around the axis of rotation 2. The respective geometry of the regions of different density may have a fluid transition 4 or also an abrupt density difference. They may pass into one another and have wavy or also jagged configurations.

[0068] FIG. 3 shows that the individual parts 5 with different densities 3 may be varied in shape in the axial direction. Along an axial extension, these density differences may run parallel to the axis of rotation 2 or also make an angle 6 with it.

[0069] FIGS. 4 to 6 show local, preferably nonsymmetrically arranged density variations 8 both in the radial 7 and the axial direction 2. Furthermore, on the one hand, the stiffness and thus the eigenfrequency of the gear wheel 1 can be influenced. On the other hand, a structure-borne sound can be absorbed, deflected, or also redirected by this shape.

[0070] FIG. 7 shows a disk-shaped construction 9 of the gear wheel 1, each layer having a different density from a neighboring layer 9. This allows, for example, a dampening of the structure-borne sound in the axial direction 2, while the strength of the gear wheel 1 may also still be designed so that high torques can still be transmitted.

[0071] FIG. 8 shows an angled arrangement of disks 9 of different density. The gear wheel 1 in particular may also have regions having only density disks running parallel and perpendicular to the axis of rotation 2, as well as regions which are transverse to the axis of rotation.

[0072] FIG. 9 shows in a sample view several channels 10 which are arranged to guide the sound in the gear wheel 1. The course of the sound-conducting channels 10 can be made dependent on how the excitation by a gearbox, for example, will then occur. The channels 10 may be entirely filled. But it is likewise possible for the channels to be only incompletely filled with a different material.

[0073] FIG. 10 shows a configuration in which the gear wheel 1 has several braces 11. The braces 11 serve for stabilizing and stiffening the gear wheel 1 while at the same time influencing the bending strength. The braces 11 may be fully or partly surrounded by sintered material. One or more segments of a brace may also be at least partly free of sintered material. Furthermore, the possibility exists for a bracing to comprise a jacketing, especially a coating. The coating preferably additionally dampens a structure-borne sound. For this, the coating is preferably open-pore, but it may also be closed-pore.

[0074] FIG. 11 shows in only schematically indicated sample form a vibrational system which can be arranged in the gear wheel 1. Preferably a liquid filling is done for this. The vibrational system is preferably designed with knowledge of the later primary speed range of the gear wheel. In this way, on the one hand, it can be active in this region. But according to one modification, it can also be designed on the basis of an eigenfrequency of the gear wheel, for example, in order to counteract an eigenfrequency.

[0075] FIG. 12 shows in a sample embodiment a gear wheel with internal predetermined cavities 12, which may be filled for example, or remain clear. For example, such a gear wheel 1 can be made by means of additive powder bed methods. Preferably, a metallic powder is filled into the cavities 12, which is loosely baked together and thereby serves as an adsorber for sound. Preferably, a cavity is filled with a bulk density of 2.5 to 3.5 g/cm.sup.3, and this only in part, preferably so that at least 50% of the cavity is filled with air. The loose material can be the same material as the gear wheel 1 or a different material. It should also be considered preferably in the case of honeycomb arrangements 13 that these may have slight deviations from each other. Preferably, the sintering neck is utilized in gear wheels, this one as well as others, for example by supplying of oil or another fluid. Copper can also be added to the sintered gear wheel. Preferably more copper is added to the inside than the outside.

[0076] The invention may be used for different gear wheels, especially spur gears, with oblique or straight teeth, and also for bevel gears. Different gear wheels, designed in this way, may find use in the most varied of applications, such as engines of every type, shift-type gearboxes, E-drive systems, household appliances, hand-operated machines, hand-guided machines, and vehicles of every kind.