Gear wheel, method for producing same and use of same

Abstract

The invention relates to a gear wheel (1) comprising a metal main body (2), which has teeth (3), and a coating (7), the coating (7) covering a circumference of the main body (2) in the region of the teeth (3) and the coating (7) being made completely from at least one amorphous metal. The invention further relates to a method for producing the gear wheel (1) and to the use of same.

Description

[0001] gear, method for its manufacture and its use

[0002] The invention relates to a gear comprising a metallic base body with teeth and a coating, wherein the coating covers a circumference of the base body in the region of the teeth. The invention further relates to a method for the additive manufacturing of such a gear and its use.

[0003] Coated gears and their production using additive manufacturing processes are known. DE 10 2017 210 877 A1 describes a 3D-printed gear. EP 3 477 158 A1 also discloses a gear produced by an additive manufacturing process, such as selective laser melting (SLM) or selective laser sintering (SLS).

[0004] EP 2 974 812 A1 describes a process for manufacturing a component from a metal alloy. For this purpose, a powder consisting of an at least partially amorphous phase is provided, and a semi-finished product is manufactured from the powder by applying the powder in layers and melting the surface through targeted local heat input. The resulting semi-finished product is then hot-pressed under mechanical pressure at a temperature between the transformation temperature and the crystallization temperature of the amorphous phase. The resulting component is used as a gear, friction wheel, wear-resistant component, housing, or part of a transmission, or as a semi-finished product.

[0005] DE 10 2020 134 672 A1 describes a wear part, for example a gear, with a wear layer and a wear indicator, each formed by additive manufacturing, preferably 3D printing.

[0006] Wear-resistant gears, due to their typically hard surfaces, exhibit high noise emissions during operation. Because of the stringent requirements for wear resistance, the use of plastics to reduce contact stiffness and noise emissions is often not feasible. The object of the present invention is to provide a wear-resistant gear that exhibits reduced noise emissions during operation. Furthermore, the invention provides a method for its manufacture.

[0007] This problem is solved for the gear by the features of independent claim 1. Further advantageous embodiments are the subject of dependent claims 2 to 4.

[0008] The gear according to the invention comprises a metallic base body with teeth and a coating, the coating covering a circumference of the base body in the region of the teeth. According to the invention, the coating is formed entirely of at least one amorphous metal.

[0009] The amorphous metal of the coating exhibits lower stiffness and a lower modulus of elasticity than crystalline wear-resistant coatings and is more flexible. Nevertheless, it offers high hardness and thus wear resistance.

[0010] The gear according to the invention has the advantage that less noise is generated during the gear's rotation. Amorphous metals have a low modulus of elasticity, which results in low contact stiffness and reduces friction in the area of ​​parts interacting with the gear.

[0011] Noise generated during the operation of the gear, where the teeth of at least two gears touch, for example during a change of direction of rotation, is significantly reduced.

[0012] The base body is made of a crystalline material, while the coating is an amorphous metallic coating. In particular, the materials of the base body and the coating also differ.

[0013] The metallic base body of the gear is preferably made of steel, such as low-alloy steel, or aluminum or an aluminum alloy, or at least one non-ferrous metal, such as bronze, or a copper alloy. The amorphous metallic coating of the gear is preferably a zirconium-, iron-, or nickel-based coating. Furthermore, steel, aluminum, a copper alloy, or a porous material can be used for the amorphous metal coating.

[0014] The coating of the gear preferably has a layer thickness in the range of 10 to 2000 pm.

[0015] The problem is further solved by a method for manufacturing a gear according to the invention as per claim 5.

[0016] The method for manufacturing a gear according to the invention includes forming the metallic base body either by mechanical processing and / or by additive manufacturing, wherein the base body is coated by forming the coating on its circumference in the area of ​​the teeth using additive manufacturing.

[0017] This method allows for quick and cost-effective production of the gear. Mass production is also possible at reasonable costs.

[0018] For the additive manufacturing of the coating and optionally also of the base body, a laser powder bed fusion (L-PBF) process is preferably used.

[0019] In a preferred embodiment of the method, the coating in the area of ​​the teeth is mechanically post-processed.

[0020] The use of a gear according to the invention to create acoustic decoupling from other parts that touch the at least one gear in a tooth engagement area, in particular in an e-axle, a roll stabilizer or a rear axle steering system, has proven successful.

[0021] The invention is explained below by way of example with reference to Figures 1 to 3.

[0022] This shows

[0023] Figure 1 is a three-dimensional view of a coated gear, Figure 2 is an enlarged section of the gear according to Figure 1 in the area of ​​two teeth, and

[0024] Figure 3 shows a section through a tooth of the gear according to Figure 2.

[0025] Figure 1 shows a gear 1 in a three-dimensional view and comprises a base body 2 with teeth 3 forming external teeth. The circumference of the gear 1 is covered with an amorphous metallic coating 7. Thus, the coating 7 covers the teeth 3 with their tooth flanks 5 and tooth tips 6, as well as each tooth root 4 arranged between the teeth.

[0026] Figure 2 shows an enlarged section of the gear 1 according to Figure 1 in the area of ​​the second teeth 3. In this view, the amorphous metallic coating 7, which is applied to the circumference of the base body 2 in the area of ​​the external teeth, can be seen.

[0027] Figure 3 shows a section through a tooth 3 of the gear 1 according to Figure 2. The base body 2 and the coating 7, which has a layer thickness SD, are visible. The base body 2 can be conventionally machined or additively manufactured. The base body 2 is preferably made of metal, in particular steel. The coating 7 is applied to the previously machined base body 2 by means of an additive manufacturing process, either or alternatively, simultaneously with the additive manufacturing of the base body 2.

[0028] The external gear teeth can then be mechanically post-processed, whereby the coating 7 on its side facing away from the base body 2 receives its final shape. This post-processing can be carried out, for example, by grinding and / or honing.

[0029] The gear 1 shown is chosen only as an example to visualize the position of the coating 7. However, other types of gears, differing in their tooth shape, number of teeth, and the like, also fall under the scope of the present invention. List of reference symbols

[0030] 1 gear

[0031] 2 basic shapes

[0032] 3 teeth

[0033] 4 Tooth base

[0034] 5 Tooth flank

[0035] 6 Tooth head

[0036] 7 amorphous metallic coating

[0037] SD layer thickness

Claims

Patent claims 1. Gear (1) comprising a metallic base body (2) with teeth (3) and a coating (7), wherein the coating (7) covers a circumference of the base body (2) in the region of the teeth (3), and wherein the coating (7) is formed entirely of at least one amorphous metal.

2. Gear (1) according to claim 1, wherein the metallic base body (2) is made of steel or aluminium or an aluminium alloy or a non-ferrous metal or a copper alloy.

3. Gear (1 ) according to claim 1 or 2, wherein the coating (7) is a zirconium, iron or nickel-based amorphous metallic coating.

4. Gear (1 ) according to one of claims 1 to 3, wherein the coating (7) has a layer thickness (SD) in the range of 10 to 2000 m.

5. Method for manufacturing a gear (1) according to any one of claims 1 to 4, wherein the metallic base body (2) is formed either by mechanical processing and / or by additive manufacturing, and wherein the base body (2) is coated by forming the coating (7) on its circumference in the area of ​​the teeth (3) by means of additive manufacturing.

6. The method of claim 5, wherein a laser powder bed fusion process is used to produce the coating (7).

7. Method according to claim 5 or 6, wherein a laser powder bed fusion process is used for the additive manufacturing of the base body (7).

8. Method according to any one of claims 5 to 7, wherein the coating (7) is mechanically post-processed in the area of ​​the teeth (3).

9. Use of at least one gear (1 ) according to one of claims 1 to 4 to form an acoustic decoupling from further parts that touch the at least one gear (1 ) in a tooth engagement area.

10. Use according to claim 9, wherein the at least one gear (1 ) is installed in an E-axle, a roll stabilizer or a rear axle steering system.

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