AT527314B1 - torque transmission device - Google Patents

Abstract

The invention relates to a multi-track torque transmission device (1) comprising a first track (3) and a second track (4), wherein the first track (3) has a first hub (9) on which the second track (4) is arranged, for which purpose the second track (4) has an opening in the axial direction (2) which is delimited by an inner circumferential surface (18), and the second track (4) is materially connected to the first hub (9) and a plurality of centering elements (21) are arranged between the first hub (9) and the inner circumferential surface (18).

Description

Description

[0001] The invention relates to a multi-track torque transmission device comprising a first track and a second track, wherein the first track has a hub on which the second track is arranged, for which purpose the second track has an opening in the axial direction which is delimited by an inner circumferential surface.

[0002] Furthermore, the invention relates to a method for producing a multi-track torque transmission device comprising a first track and a second track, wherein the first track is produced with a hub on which the second track is arranged, for which purpose an opening is formed in the axial direction in the second track, which is delimited by an inner circumferential surface.

[0003] In electric axles, two-stage reduction gears parallel to the axis are often installed for torque conversion. The architecture is usually in the form of a two-stage spur gear set that is mounted on an intermediate shaft. For manufacturing reasons, the larger gear is usually pressed on and/or welded to the shaft. The pressed-on gears can be made of steel or sintered material.

[0004] The material-locking connection of sintered components is known from the prior art. Due to the characteristics of sintered components, in particular their porosity due to their production, a material-locking connection of sintered components is not easy to implement. Processes are often carried out, as described for example in AT 513 429 A1, according to which the area to be welded is oxidized with steam and then carburized before welding. Compared to pressing, this is a relatively complex process.

[0005] The present invention is based on the object of creating a possibility for the use of sintered components in multi-stage transmission units that can be easily implemented on a large scale.

[0006] The object is achieved in the torque transmission device mentioned at the outset in that the second track is integrally connected to the hub and that several centering elements are arranged between the hub and the inner circumferential surface.

[0007] Furthermore, the object of the invention is achieved with the method mentioned at the outset, according to which a plurality of centering elements are arranged between the hub and the inner circumferential surface, so that when the second track is arranged on the hub of the first track, a joining gap is formed in which a material connection is established between the first track and the second track.

[0008] The advantage here is that, thanks to the centering elements, the gap between the hub and the second track for the additive to form the material-locking connection can be made very even over the entire circumference, so that the bond strength can be completely equalized. The centering elements can also ensure a minimum gap for receiving the additive to form the material-locking connection. In addition, the centering elements can prevent a radial offset of the two tracks. The advantage here is that centering elements are relatively easy to produce using pressing technology, so that mechanical post-processing can be omitted, which can improve the cost-effectiveness of manufacturing the torque transmission device.

[0009] According to one embodiment of the invention, it can be provided that the centering elements are arranged on an outer surface of the hub and/or on the inner surface of the second track. This arrangement of the centering elements not only achieves the centering of the two tracks to be joined, but also creates a receiving space for a pasty additive. This enables, among other things, a variant of the method according to which a pasty sintered solder is used, which is arranged between the centering elements.

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[0010] To improve the bond strength, according to a further embodiment of the invention, the centering elements can have a radial height of between 0.05 mm and 2 mm. Below a height of 0.05 mm, the formation of a complete material bond between the tracks can only be achieved with greater effort, which reduces the cost-effectiveness of the production of the torque transmission device. At a height of more than 2 mm, undesirable metallic phases can sometimes form between the additive and one of the two stages of the torque transmission device to be connected, which can reduce the bond strength.

[0011] According to a preferred embodiment of the invention, centering elements can be formed integrally with the first track and/or centering elements can be formed integrally with the second track, whereby the assembly of the two tracks can be simplified.

[0012] An easily implementable variant of the centering elements or the centered arrangement of the second track to the hub can be achieved if the centering elements are tooth-shaped.

[0013] According to a further embodiment of the invention, it can also be provided that the centering elements are designed in a ramp shape. With the ramp-shaped design of the centering elements, designs of the torque transmission device can also be created in which a readjustment of the two tracks is possible during the joining process. It is therefore also possible to take existing manufacturing tolerances of the tracks into account by offsetting the longitudinal center axes of the two tracks in relation to one another in the radial direction, in order to be able to arrange, for example, an off-center toothing of the first track without a radial offset to the second track.

[0014] For easier (automated) centering of the two tracks relative to each other, according to an embodiment variant of the invention, it can be provided that at least three centering elements are arranged on the hub and/or at least three centering elements are arranged on the second track.

[0015] According to another embodiment of the invention, the centering elements can be arranged on an end face of the hub and/or on an end face of the second track. If only these centering elements are provided, the joint gap can be formed continuously in the circumferential direction, which can influence the bond strength, so that a radial width of the joint gap can be reduced if necessary.

[0016] A simple automation of the joining process can be achieved if, according to an embodiment variant of the invention, the centering elements are conical in shape.

[0017] Preferably, according to an embodiment of the invention, the material-locking connection is a sintered soldered connection, since this allows the above-mentioned problems when welding sintered components to be avoided due to the comparatively lower temperature during sintered soldering.

[0018] According to a further preferred embodiment, the first track is produced by a powder metallurgical process so that the centering elements can be more easily taken into account during powder pressing.

[0019] According to a variant of the method, in order to simplify the process sequence, it can be provided that the sinter soldering and the sintering of the first track are carried out in a common process step. With this variant, the bond strength can also be improved, since the bond formation in the edge layers of the joint gap can be formed to extend deeper into the first track.

[0020] For a better understanding of the invention, it is explained in more detail with reference to the following figures.

[0021] They show in a simplified, schematic representation:

[0022] Fig. 1 shows a longitudinal section through a torque transmission device; [0023] Fig. 2 shows a variant embodiment of centering elements;

[0024] Fig. 3 shows another embodiment of centering elements;

[0025] Fig. 4 shows a further embodiment of centering elements;

[0026] Fig. 5 shows a further embodiment of centering elements;

[0027] Fig. 6 shows a further embodiment of centering elements;

[0028] Fig. 7 shows a ramp-shaped centering element;

[0029] Fig. 8 shows a further embodiment of centering elements.

[0030] To begin with, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or identical component designations, whereby the disclosures contained in the entire description can be transferred analogously to identical parts with identical reference symbols or identical component designations. The position information chosen in the description, such as top, bottom, side, etc., also refers to the figure directly described and shown, and these position information must be transferred analogously to the new position in the event of a change in position.

[0031] In Fig. 1, a multi-stage torque transmission device 1 is shown in longitudinal section.

[0032] Multi-stage means that the torque transmission device 1 has at least two stages that are arranged one behind the other in an axial direction 2 of the torque transmission device 1. The stages form a first track 3 and a second track 4. The torque transmission device 1 can therefore also be referred to as a multi-track torque transmission device 1.

[0033] The torque transmission device 1 can also have more than two tracks 3, 4, for example three or four or five.

[0034] The first track 3 is preferably a gear wheel and in this embodiment has a spur gear 5. However, the first track 3 can also be a V-belt wheel or a toothed belt wheel.

[0035] The second track 4 is preferably also a gear wheel and in this embodiment has a spur gear 6. However, the second track 4 can also be a V-belt wheel or a toothed belt wheel.

[0036] Mixed variants are also possible. For example, one of the tracks 3, 4 can be a gear wheel and the other track 4, 3 a toothed belt wheel or a V-belt wheel.

[0037] The first track 3 has a first outer diameter 7. The second track 4 has a second outer diameter 8. The outer diameters 7, 8 are the outermost diameters of the tracks 3, 4. In the design variant as gears, the outer diameters 7, 8 are equal to the tip diameters of the spur gears 5, 6.

[0038] Preferably, the first outer diameter 7 is larger than the second outer diameter 8. However, the first outer diameter 7 can also be the same size or smaller than the second outer diameter 8.

[0039] The first track 3 has a hub 9. The hub 9 is preferably formed integrally with the rest of the first track 3. The second track 4 is at least partially arranged on this hub 9.

[0040] To accommodate a shaft or axle not shown in Fig. 1, the first track 3 has a recess 10 (bore). A first bearing element 11, for example a rolling bearing, can be arranged in this recess 10 between the shaft or axle and the first track 3.

[0041] The second track 4 can also have a second hub 12 on which a second bearing element 13 is arranged. The second track 4 can also be arranged on a shaft or axle on which the second bearing element 13 is optionally arranged. For example, the second hub 12 can be an intermediate shaft. The second track 4 is preferably formed in one piece with the second hub 12 or the shaft or the axle. The second track 4 can also be connected to the second hub 12 in a materially bonded and/or positively bonded and/or non-positively bonded manner.

[0042] The second track 4 can also have an opening 14 running in the axial direction 2. An inner diameter 15 of the opening 14 can be the same size as an inner diameter 16 of the first hub 9.

[0043] The first hub 9 can be designed or arranged in the axial direction 2 directly adjacent to the second hub 12 or the (intermediate) shaft or at a distance therefrom.

[0044] For its arrangement on the first hub 9, the second track 4 has an opening 17 running in the axial direction 2, which is delimited by an inner circumferential surface 18 of the second track 4. An annular web 20 can be formed on an outer circumferential surface 19 of the first hub 9, against which the second track 4 can be arranged adjacently.

[0045] The second spur gear 6 can - viewed in the axial direction 2 - be arranged at a distance from the first spur gear 5, as can be seen from Fig. 1.

[0046] In the preferred embodiment, the first track 3 is a sintered component, i.e. manufactured using a powder metallurgical process. Furthermore, the second track 4 in the preferred embodiment is a component made of a solid material, for example a component made of a cast material.

[0047] In comparison to a sintered component, a component made of a solid material has no pores, except for defects.

[0048] The second track 4 can also be a sintered component. In this case, the second track 4 is arranged on an (intermediate) shaft which consists of a solid material. In the event that the second track 4 is also designed as a sintered component, the following embodiments can also be used for connecting the second track 4 to the (intermediate) shaft.

[0049] The second track 4 is integrally connected to the first hub 9. Preferably, the second track 4 is connected to the first hub 9 by sintering soldering. Other methods for integrally connecting the second track 4 to the first hub 9 are also possible, although not preferred.

[0050] Sinter soldering is a known process in itself, so that further details can be found in the relevant prior art. It should only be mentioned that a solder can be used which forms the sinter solder connection between the first hub 9 and the second track 4 at sintering temperatures in the range between 700 °C and 1,300 °C. The solder can be applied in solid or pasty form, for example. For example, the solder can be a copper foil or a powder, which may be pressed into a tablet, a wire, etc. Different combinations of copper, iron, nickel, manganese, tin, etc. can be used as solder materials. In the event that the first track 3 is designed as a sintered component, the sintering solder can be applied to the already sintered first track 3 or to the pre-sintered first track 3 and then, after the second track 4 has been arranged on the first hub 9, subjected to a further heat treatment at a temperature from the above-mentioned range or to final sintering to form the sintering solder connection. According to one embodiment of the invention, the sintering solder can be applied to the green compact and, after the second track 4 has been arranged on the first hub 9, can be sintered together with the green compact in one or more stages.

[0051] The sintering can be carried out for a period of between 10 seconds and 180 minutes. Furthermore, the sintering can be carried out under an inert gas atmosphere if necessary.

Preferably, the sintering process is carried out in a continuous furnace.

[0052] The production of a sintered component is also known per se. This method comprises the steps of powder pressing to produce a green compact and sintering the green compact.

[0053] It is provided that a plurality of centering elements 21 are arranged between the first hub 9 and the inner surface 18, as can be seen from an embodiment variant in Fig. 2. In general, centering elements 21 can be arranged on the outer surface 19 of the first hub 9 (as shown in Fig. 2) and/or on the inner surface 18 of the second track 4.

[0054] Centering elements 21 arranged or formed on the first hub 9 can, as shown in Fig. 2, rest on the inner circumferential surface 18 of the second track 4. Centering elements 21 arranged or formed on the inner circumferential surface 18 can rest on the first hub 9, i.e. the outer circumferential surface 19.

[0055] According to another embodiment variant, it can be provided that centering elements 21 on the first hub 9 rest against centering element 21 on the inner circumferential surface 18 of the second track 4.

[0056] According to one embodiment variant, the centering elements 21 can have a radial height 22 (height 22 in the radial direction) between 0.05 mm and 2 mm, in particular between 0.05 mm and 1 mm.

[0057] Furthermore, the centering elements 21 can have a length in the axial direction 2 (see Fig. 1) between 20% and 100%, in particular between 50% and 100%, of a length 23 (see Fig. 1) of the entire overlap section between the first hub 9 and the second track 4.

[0058] All centering elements 21 of the torque transmission device 1 can be designed the same. However, it is also possible to arrange centering elements 21 with different designs. The differences can relate, for example, to the radial height 22 and/or the length in the axial direction 2.

[0059] In principle, it is conceivable that the centering elements 21 are inserted, for example pushed, into a gap 24 between the outer surface 19 of the first hub 9 and the inner surface 18 of the second track 4. If necessary, grooves can be formed in one of the above-mentioned surfaces to accommodate the centering elements 21. In the preferred embodiment, however, the centering elements 21 are integral with the first track 3 and/or the centering elements 21 are integral with the second track 4. In particular, the centering elements 21 can be integral with the first track 3, since they can thus be easily produced using a powder metallurgical process.

[0060] For the sake of completeness, it should be noted that the intermediate space 24 results from the fact that the first hub 9 has a smaller outer diameter than an inner diameter of the second track 4 in the area of the overlap section. The intermediate space 24 serves to accommodate the additional material, i.e. preferably the sintering solder, for forming the material-locking connection between the first and second tracks 3, 4. The centering elements 21 thereby ensure that the intermediate space 24 has as uniform a height as possible in the radial direction, which is achieved by centering the first hub 9 in the opening 14 of the second track 4 in the overlap section between the first and second tracks 3, 4.

[0061] In the embodiment of the centering elements 21 shown in Fig. 2, these are tooth-shaped. They have a rectangular cross-section. However, the centering elements 21 can also have a different cross-sectional shape. For example, they can be square or trapezoidal. For better contact with the inner surface 18 of the second track 4, the tooth heads resting against it can be rounded, in particular with a rounding radius that corresponds to the rounding radius of the second track 4 on the inner surface 18. However, it is also possible for the rounding radius of the

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Tooth heads are smaller than the said rounding radius of the second track 4, whereby the contact surfaces of the centering elements 21 on the inner surface 18 can be reduced. This means that an additive for the connection formation between the first and second tracks 3, 4 can also be introduced into these areas.

[0062] The flanks of the tooth-shaped centering elements 21 can be flat, as shown in Fig. 2. However, they can also be rounded - viewed in cross section - as is known, for example, from the teeth of gear teeth. The rounding of the tooth flanks of the centering elements 21 can improve the flow of the additive, particularly during sinter soldering.

[0063] For better adhesion of the additive to the centering elements 21 before the formation of the material connection of the two tracks 3, 4, the flanks or generally the centering elements 21 can be provided with a surface structure or a surface roughness.

[0064] Fig. 3 shows a further embodiment of centering elements 21. These centering elements 21 are ramp-shaped.

[0065] In the embodiment according to Fig. 3, both the first hub 9 on the outer surface 19 and the second track 4 on the inner surface 18 have ramp-shaped centering elements 21 in cross section. This design allows the ramp surfaces of the centering elements 21 of the first hub 9 and the centering elements 21 of the second track 4 that are adjacent to them to slide off one another by rotating the first hub 9 and/or the second track 4 relative to one another, thus centering the second track 4 with respect to the first hub 9. The radial height 22 of the centering elements 21 can also be a maximum of the desired radial height of the intermediate space 24 in this embodiment (as in the embodiment according to Fig. 2).

[0066] Fig. 4 shows another embodiment of ramp-shaped centering elements 21. The ramp surfaces extend through the decrease in the radial height 22 in the axial direction 2 in the longitudinal extension of the centering elements 21 in the axial direction 2.

[0067] In addition, the centering elements 21 may optionally also have a course of the ramp surfaces with a radial height 22 increasing in the circumferential direction (as in the embodiment according to Fig. 3).

[0068] In the embodiment according to Fig. 4, only one centering element 21 is shown on the first hub 9. In this embodiment, this can also interact with a further centering element 21 on the inner surface 18 of the second track 4, as is shown, for example, in Fig. 3. Thus, in the embodiment of the centering elements 21 according to Fig. 4, (the) centering elements 21 can also be arranged on the first hub 9 and/or (the) centering elements 21 on the second track 4.

[0069] According to a preferred embodiment of the torque transmission device 1, at least three centering elements 21 are arranged on the first hub 9 and/or at least three centering elements 21 on the second track 4. The number of centering elements 21 on the first hub 9 and/or on the second track 4 can be selected from a range of three to ten centering elements 21.

[0070] Preferably, the centering elements 21 are evenly distributed over the circumference of the first hub 9 or over the inner circumference of the second track 4. For example, three centering elements 21 are arranged offset from one another by 120° (each measured between the centers of the width of the centering elements 21 in the circumferential direction).

[0071] Fig. 5 shows another embodiment of centering elements 21 which can be arranged alternatively or in addition to the above-described centering elements 21 of the torque transmission device 1. In this embodiment, the centering elements 21 are arranged on an end face of the first hub 9 and/or on an end face of the second track 4. In the specific embodiment shown, the centering elements 21

conical, whereby the two conical surfaces can slide against each other for centering from the first hub 9 to the second track 4. The conical surfaces form the transition from an end face 25 of the second track 4 to its inner surface 18 and the transition from an end face 26 of the first track 3 to the outer surface 19 of the first hub 9. The end face 26 of the first track 3 can be formed, for example, on the annular web 20 shown in Fig. 1.

[0072] Fig. 6 shows a section of a further embodiment of the torque transmission device 1. Again, sections of the second track 4 and the first hub 9 on which the second track 4 is arranged can be seen. Reference is made to the above explanations.

[0073] In this embodiment, one or more centering elements 21 are arranged on the inner surface 18 of the second track 4 and one or more centering elements 21 on the outer surface of the hub 9, in particular formed integrally with the respective component. The centering elements 21 are designed as projections and protrude into the gap 24 between the second track 4 and the hub 9. One centering element 21 on the inner surface 18 and one centering element 21 on the outer surface 19 of the hub 9 work together to form the most uniform gap 24 possible between the second track 4 and the hub 9. The radial height of a combination of a centering element 21 on the inner surface 18 and a centering element 21 on the outer surface 19 of the hub 9 is dimensioned such that an overlap is formed in the assembled state of the torque transmission device 1. For assembly, the second track 4 and the hub 9 are positioned relative to one another such that the at least one centering element 21 on the inner surface 18 of the second track 4 is arranged in the circumferential direction 27 next to the centering element 21 on the outer surface 19 of the hub 9. After the second track 4 has been pushed onto the hub 9 or the hub 9 has been pushed into the second track 4, they are rotated relative to one another in the circumferential direction 27 so that the centering elements 21 are arranged one above the other in the radial direction and the overlap is formed, as shown in Fig. 6.

[0074] Preferably, one of the centering elements 21 of a pair of centering elements 21 has a greater length in the circumferential direction 27 than the second centering element 21 of the pair. Preferably, this is the centering element 21 on the inner circumferential surface 18 of the second track, as shown in Fig. 6.

[0075] In order to simplify the rotatability in the circumferential direction 27, a centering element 21 or both centering elements 21 of a pair can be designed with ramps 28 (bevels) at the beginning and/or at the end, as shown in particular in Fig. 7 as an example of a centering element 21. The ramps 28 can enclose an angle 29 between 45°, in particular 60°, and 88°, in particular 75°, with the radial direction. In addition, transitions between the individual sections of the centering elements 21 can be rounded, i.e. not sharp-edged.

[0076] Fig. 8 shows a section of a variant of the torque transmission device 1 with conical centering elements 21. A centering element 21, preferably fully continuous in the circumferential direction 27, is arranged on the inner surface 18 of the second track 4 and a centering element 21, preferably fully continuous in the circumferential direction 27, is arranged on the outer surface 19 of the hub 9. The two centering elements 21 work together to form the intermediate space 24 in that the surfaces of the centering elements 21 facing one another slide on one another.

[0077] The conical surfaces can enclose an angle of between 10°, in particular 20°, and 50°, in particular 30°, with the axial direction 2. In addition, transitions in the area of the centering elements 21 can be rounded, i.e. not sharp-edged.

[0078] With the centering elements 21, a joint gap (the gap 24) is formed when the second track 4 is arranged on the first hub 9 of the first track 3, in which the material

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a coherent connection is established between the first track 3 and the second track 4.

[0079] For the sake of clarity, it should finally be pointed out that for a better understanding of the structure of the torque transmission device 1, the latter is not necessarily shown to scale.

REFERENCE SYMBOL LIST

1 torque transmission device

2 axial direction

3 lane

4 lane

5 spur gearing

6 spur gearing

7 outer diameters

8 outer diameters

9 hub

10 recess

11 bearing element

12 hub

13 bearing element

14 breakthrough

15 inner diameter

16 inner diameters

17 breakthrough

18 lateral surface

19 lateral surface

20 Ringsteg

21 Centering element 22 Height

23 length

24 gap 25 front surface

26 frontal area

27 Circumferential direction 28 Ramp

29 angles

Claims (14)

patent claims 1. Multi-track torque transmission device (1) comprising a first track (3) and a second track (4), wherein the first track (3) has a first hub (9) on which the second track (4) is arranged, for which purpose the second track (4) has an opening in the axial direction (2) which is delimited by an inner circumferential surface (18), characterized in that the second track (4) is materially connected to the first hub (9) and that a plurality of centering elements (21) are arranged between the first hub (9) and the inner circumferential surface (18). 2, Torque transmission device (1) according to claim 1, characterized in that centering elements (21) are arranged on an outer surface (19) of the first hub (9) and/or on the inner surface (18) of the second track (4). 3. Torque transmission device (1) according to claim 2, characterized in that the centering elements (21) have a radial height between 0.05 mm and 2 mm. 4. Torque transmission device (1) according to claim 2 or 3, characterized in that centering elements (21) are formed integrally with the first track (3) and/or that centering elements (21) are formed integrally with the second track (4). 5. Torque transmission device (1) according to one of claims 1 to 4, characterized in that the centering elements (21) are tooth-shaped. 6. Torque transmission device (1) according to one of claims 1 to 4, characterized in that the centering elements (21) are ramp-shaped. 7. Torque transmission device (1) according to one of claims 1 to 6, characterized in that at least three centering elements (21) are arranged on the first hub (9) and/or at least three centering elements (21) on the second track (4). 8. Torque transmission device (1) according to one of claims 1 to 7, characterized in that the centering elements (21) are arranged on an end face (26) of the first hub (9) and/or on an end face (25) of the second track (4). 9. Torque transmission device (1) according to one of claims 1 to 8, characterized in that the centering elements (21) are conical. 10. Torque transmission device (1) according to one of claims 1 to 9, characterized in that the material-locking connection is a sintered solder connection. 11. Method for producing a multi-track torque transmission device (1) comprising a first track (3) and a second track (4), wherein the first track (3) is produced with a first hub (9) on which the second track (4) is arranged, for which purpose an opening is formed in the axial direction (2) in the second track (4), which is delimited by an inner circumferential surface (18), characterized in that a plurality of centering elements (21) are arranged between the first hub (9) and the inner circumferential surface (18), so that when the second track (4) is arranged on the first hub (9) of the first track (3), a joining gap is formed in which a material connection is established between the first track (3) and the second track (4). 12. The method according to claim 11, characterized in that the first track (3) is produced by a powder metallurgical process and the material-locking connection is produced by means of sintering soldering. 13. Method according to claim 12, characterized in that a pasty sintered solder is used, which is arranged between the centering elements (21). 14. Method according to one of claims 11 to 13, characterized in that the sintering soldering and the sintering of the first track (3) are carried out in a common method step. Here 3 sheets of drawings